【Technical Field】
This application claims the benefit of Korean Patent 5 Application No. 10-
2015-0172265 filed on December 4, 2015 with the Korean Intellectual Property
Office, the disclosure of which is herein incorporated by reference in its entirety.
The present invention relates to an indirect cooling system capable of
uniformly cooling battery modules and a battery pack including the same.
10 【Background】
In recent years, a secondary battery, which can be charged and
discharged, has been widely used as an energy source for wireless mobile
devices. In addition, the secondary battery has attracted considerable
attention as a power source for electric vehicles (EV), hybrid electric vehicles
15 (HEV), and plug-in hybrid electric vehicles (Plug-in HEV), which have been
developed to solve problems, such as air pollution, caused by existing gasoline
and diesel vehicles that use fossil fuels.
Small-sized mobile devices use one or a few battery cells for each
device. On the other hand, middle or large-sized devices, such as vehicles,
20 use a battery module including a plurality of modularized battery cells or a
battery pack including a plurality of battery modules electrically connected to
each other, because high output and large capacity are necessary for such
middle or large-sized devices.
3
Preferably, a middle or large-sized battery module or a middle or largesized
battery pack is manufactured so as to have as small a size and weight as
possible. For this reason, a prismatic battery or a pouch-shaped battery, which
can be stacked with high integration and has a small weight to capacity ratio, is
usually used as a battery cell (i.e. a unit cell) of the middle 5 or large-sized battery
module or the middle or large-sized battery pack. In particular, much interest
is currently focused on the pouch-shaped battery, which uses an aluminum
laminate sheet as a sheathing member, because the pouch-shaped battery is
lightweight, the manufacturing cost of the pouch-shaped battery is low, and it is
10 easy to modify the shape of the pouch-shaped battery.
Battery cells constituting the middle or large-sized battery module or the
middle or large-sized battery pack are secondary batteries that can be charged
and discharged. Consequently, a large amount of heat is generated from the
high-output, large-capacity secondary batteries during the charge and discharge
15 of the secondary batteries. In particular, the laminate sheet of a pouch-shaped
battery cell has a polymer material exhibiting low thermal conductivity coated on
the surface thereof, with the result that it is difficult to effectively lower the
overall temperature of the battery cell.
If heat, generated from the battery cells during the charge and
20 discharge of the battery cells, is not effectively removed from the battery cells,
the heat accumulates in the battery cells, with the result that deterioration of the
battery cells is accelerated. According to circumstances, the battery cells may
even catch fire or explode. For this reason, a high-output, large-capacity
battery module or a high-output, large-capacity battery pack needs a cooling
4
system for cooling battery cells mounted in the battery module or the battery
pack.
Meanwhile, at least one battery module mounted in a middle or largesized
battery pack is generally manufactured by stacking a plurality of battery
cells with high integration. In this case, the battery cells 5 are stacked in the
state in which the battery cells are arranged at predetermined intervals such
that heat, generated from the battery cells during the charge and discharge of
the battery cells, is removed. For example, the battery cells may be
sequentially stacked in the state in which the battery cells are arranged at
10 predetermined intervals without using an additional member. Alternatively, in
the case in which the battery cells have low mechanical strength, one or more
battery cells may be mounted in a cartridge, and a plurality of cartridges may be
stacked to constitute a battery module. In the above structure, refrigerant flow
channels may be defined between the stacked battery cells or between the
15 stacked battery modules such that heat accumulating between the stacked
battery cells or between the stacked battery modules is effectively removed.
In the battery pack cooling structure described above, however, a
plurality of refrigerant flow channels must be provided so as to correspond to a
plurality of battery cells or battery modules, with the result that the overall size
20 of the battery pack is increased.
In addition, if the battery pack includes a larger number of battery cells,
a larger number of parts are added to the cooling structure, with the result that
the volume of the battery pack is increased, the manufacturing process is
complicated, and cost incurred to design the cooling structure is greatly
5
increased.
Furthermore, a plurality of parts is used to constitute a structure in
which heat from the battery modules or the battery cells is transferred to the
refrigerant flow channels, by which the heat is removed, with the result that
thermal conductivity is lowered and thus cooling 5 efficiency is reduced.
Therefore, there is a high necessity for a cooling system that can be
designed so as to have a compact structure while exhibiting high cooling
efficiency.
【Technical Problem】
10 The present invention has been made to solve the above problems and
other technical problems that have yet to be resolved.
Specifically, it is an object of the present invention to provide a cooling
system having a compact structure that is capable of uniformly removing heat
generated from battery modules without using a large number of members.
15 It is another object of the present invention to provide a battery pack
configured to be installed in a device, such as a vehicle, without positional
limitations.
【Technical Solution】
In accordance with one aspect of the present invention, the above and
20 other objects can be accomplished by the provision of a cooling system for
cooling a plurality of battery modules, the cooling system including a
refrigerant introduction port, through which liquid refrigerant is introduced, a
refrigerant discharge port, through which the liquid refrigerant is discharged, a
plurality of refrigerant pipes configured to communicate with the refrigerant
6
introduction port or the refrigerant discharge port, one or more pipe connection
members configured to interconnect two or more of the refrigerant pipes such
that the refrigerant pipes communicate with each other, the pipe connection
members being configured to divide the liquid refrigerant or to change the flow
direction of the liquid refrigerant between the connected refrigerant 5 pipes, and
a plurality of cooling plates, each of which has a hollow flow channel
communicating with at least one of the refrigerant pipes and each of which has
one surface on which a corresponding one of the battery modules is mounted,
the liquid refrigerant being circulated along the hollow flow channel, wherein
10 the liquid refrigerant is divided by the pipe connection members, the divided
streams of liquid refrigerant are supplied to the respective cooling plates, and
the divided streams of liquid refrigerant are combined after being discharged
from the respective cooling plates, whereby the battery modules are cooled by
the respective cooling plates as the result of thermal conduction of the divided
15 streams of liquid refrigerant.
That is, in the cooling system according to the present invention, the
coolant flow channels are defined in the cooling plates, on which the battery
modules are mounted. Compared to the structure in which the coolant flow
channels are defined between the battery modules or between the battery
20 cells, therefore, the cooling system according to the present invention has a
compact structure. In addition, the divided streams of liquid refrigerant are
introduced into the respective cooling plates to independently cool the battery
modules mounted on the respective cooling plates, thereby achieving high
uniformity of cooling of the battery modules.
7
Particularly, in the cooling system according to the present invention,
the liquid refrigerant is supplied to the respective cooling plates in the state in
which the temperature of the liquid refrigerant is almost uniform as the result of
systematic coupling among the refrigerant pipes. Hereinafter, the structure of
the cooling system according to the present invention will 5 be described in
detail through the following non-limiting examples.
In a concrete example, the refrigerant pipes may include a first
refrigerant pipe connected to the refrigerant introduction port, a second
refrigerant pipe connected to the refrigerant discharge port, a plurality of third
10 refrigerant pipes disposed between the first refrigerant pipe and the second
refrigerant pipe in the state of being connected to the respective pipe
connection members such that the third refrigerant pipes communicate with
the first refrigerant pipe and the second refrigerant pipe, and a plurality of
fourth refrigerant pipes connected to the third refrigerant pipes via the pipe
15 connection members, the fourth refrigerant pipes also being connected to the
flow channels of the respective cooling plates.
More specifically, in the present invention, the third refrigerant pipes
may be connected to the pipe connection members in order to guide the overall
circulation of the liquid refrigerant. In addition, some of the third refrigerant
20 pipes may be connected to the first refrigerant pipe and the second refrigerant
pipe, with the result that the refrigerant introduction port and the refrigerant
discharge port may communicate with the third refrigerant pipes.
Consequently, the liquid refrigerant may flow from the refrigerant
introduction port to the first refrigerant pipe, and may then be circulated along
8
the third refrigerant pipes. Subsequently, the liquid refrigerant may be
discharged through the refrigerant discharge port via the second refrigerant
pipe.
The fourth refrigerant pipes are pipes disposed between the third
refrigerant pipes, along which the liquid refrigerant is circulated, 5 and the
cooling plates for interconnecting the third refrigerant pipes and the cooling
plates. The fourth refrigerant pipes may guide the liquid refrigerant from the
third refrigerant pipes to the cooling plates, or may guide the liquid refrigerant
from the cooling plates to the third refrigerant pipes.
10 The first refrigerant pipe and the second refrigerant pipe may each
have an inner diameter greater than the inner diameter of each of the other
refrigerant pipes such that a large amount of liquid refrigerant can be
introduced into the first refrigerant pipe and a large amount of liquid refrigerant
can be discharged from the second refrigerant pipe and such that the liquid
15 refrigerant can be pressurized and accelerated when the liquid refrigerant flows
from a refrigerant pipe having a larger inner diameter to a refrigerant pipe
having a smaller inner diameter. Specifically, the first refrigerant pipe and the
second refrigerant pipe may each have an inner diameter equivalent to 101%
to 200% of the inner diameter of each of the third refrigerant pipes.
20 If the first refrigerant pipe and the second refrigerant pipe each have
an inner diameter less than 101% of the inner diameter of each of the third
refrigerant pipes, the amount of liquid refrigerant that is introduced and
discharged is too small to be smoothly circulated in the cooling system, and
the liquid refrigerant is not sufficiently pressurized or accelerated, which is not
9
desirable.
If the first refrigerant pipe and the second refrigerant pipe each have
an inner diameter greater than 200% of the inner diameter of each of the third
refrigerant pipes, on the other hand, the overall size of the cooling system is
increased, and the mobility of the liquid refrigerant in the 5 pipe connection
members connected to the third refrigerant pipes is reduced due to excessive
fluid pressure, which is also not desirable.
Meanwhile, at least one of the pipe connection members may be
connected to at least one of the third refrigerant pipes and at least one of the
10 fourth refrigerant pipes such that the liquid refrigerant is divided and distributed
into the at least one of the third refrigerant pipes and the at least one of the
fourth refrigerant pipes, thereby adjusting the flow direction of the liquid
refrigerant.
That is, some of the liquid refrigerant may flow into a fourth refrigerant
15 pipe through a pipe connection member, and the remainder of the liquid
refrigerant may flow along a third refrigerant pipe.
Subsequently, the remainder of the liquid refrigerant may be divided
and distributed into another fourth refrigerant pipe and another third refrigerant
pipe through another pipe connection member.
20 Alternatively, at least one of the pipe connection members may be
connected to at least one of the third refrigerant pipes and at least one of the
fourth refrigerant pipes such that liquid refrigerant divided and distributed into
the at least one of the third refrigerant pipes and the at least one of the fourth
refrigerant pipes is combined into a single body of liquid refrigerant, thereby
10
adjusting the flow rate of the liquid refrigerant.
Specifically, the liquid refrigerant is circulated along the flow channels
defined in the cooling plates, flows into the fourth refrigerant pipes, and reaches
the pipe connection members. Since the third refrigerant pipes are connected
to the pipe connection members, the liquid refrigerant 5 flowing in the fourth
refrigerant pipes is combined with the liquid refrigerant flowing in the third
refrigerant pipes in the pipe connection members.
Each of the pipe connection members may include a plurality of
connection conduits connected to the refrigerant pipes in order to adjust the
10 flow direction of the liquid refrigerant and to combine the divided streams of
liquid refrigerant.
Specifically, each of the pipe connection members may include n
(n≥2) connection conduits for interconnecting the refrigerant pipes in the state
in which ends of the connection conduits are inserted into the refrigerant
15 pipes. When n is equal to or greater than 3, at least one of the connection
conduits may have an inner diameter equivalent to 5% to 99% of the inner
diameter of each of the other connection conduits.
Consequently, the liquid refrigerant may be divided and distributed into
the respective connection conduits such that the liquid refrigerant can be
20 guided to different refrigerant pipes.
In addition, the liquid refrigerant may be divided and distributed into
the connection conduits at different flow speeds and flow rates due to different
inner diameters of the connection conduits.
In general, cooling speed is greatly affected by the circulation of the
11
liquid refrigerant. For this reason, the flow speed of the liquid refrigerant is
critical. As a result, it is advantageous to supply the liquid refrigerant to the
cooling plates, in which cooling is actually performed, at a high flow speed.
Consequently, the connection conduits through which the liquid refrigerant is
distributed into the cooling plates may have a relatively small 5 inner diameter.
The fourth refrigerant pipes, which communicate with the respective cooling
plates, may be connected to the connection conduits through which the liquid
refrigerant is distributed into the cooling plates.
Meanwhile, it is advantageous for a large amount of liquid refrigerant
10 not having undergone heat exchange, i.e. a large amount of liquid refrigerant
having a temperature substantially equal to the temperature of the liquid
refrigerant when the liquid refrigerant is introduced through the refrigerant
introduction port, to flow along the third refrigerant pipes, which guide the
overall circulation of the liquid refrigerant, and to be divided and distributed
15 through the respective pipe connection members, before the liquid refrigerant
is supplied to the cooling plates. For this reason, the connection conduits
connected to the third refrigerant pipes may have a relatively large inner
diameter.
That is, in the cooling system according to the present invention, the
20 connection conduits connected to the respective refrigerant pipes may have
different inner diameters such that the liquid refrigerant can be distributed into
the respective refrigerant pipes at different flow speeds and different flow rates.
As described above, the difference in inner diameter between the connection
conduits may be 5% to 99%.
12
If the difference in inner diameter between the connection conduits is
less than 1%, the liquid refrigerant is little pressurized and accelerated when
the liquid refrigerant is divided, with the result that rapid circulation in the
cooling plates is not achieved, which is not desirable. If the difference in inner
diameter between the connection conduits is greater than 5 99%, on the other
hand, the flow pressure of the liquid refrigerant is increased, whereas the flow
speed of the liquid refrigerant is decreased, which is also not desirable.
In consideration of the above description, the difference in inner
diameter between the connection conduits may be specifically 10% to 90%, and
10 more specifically 30% to 80%.
As described above, the flow speed and flow rate of the liquid
refrigerant affect the cooling uniformity and efficiency of the cooling system.
In the present invention, therefore, the inner diameters of the refrigerant pipes
may also be designed in consideration of the flow speed and flow rate of the
15 liquid refrigerant. Consequently, the flow speed and flow rate of the liquid
refrigerant flowing in the refrigerant pipes may be set based on the inner
diameters of the connection conduits and the inner diameters of the refrigerant
pipes connected to the connection conduits.
In the cooling system according to the present invention, however, in
20 the case in which the third refrigerant pipes, which guide the overall circulation
of the liquid refrigerant, and the fourth refrigerant pipes, which guide only a
portion of the liquid refrigerant, are considerably different from each other in
terms of the flow speed and flow rate of the liquid refrigerant, the overall
mobility of the liquid refrigerant may be reduced or the liquid refrigerant may
13
stagnate at specific points in the cooling system (for example, the pipe
connection members through which the liquid refrigerant is combined), with
the result that the cooling efficiency of the cooling system may be greatly
reduced. For this reason, the ratio of the inner diameter of the fourth
refrigerant pipes to that of the third refrigerant pipes may have 5 a specific value.
In a concrete example, each of the fourth refrigerant pipes may have
an inner diameter equivalent to 5% to 99% of the inner diameter of each of the
third refrigerant pipes.
The inner diameter of each of the fourth refrigerant pipes may be set
10 to accelerate the liquid refrigerant toward the cooling plates in the same
manner as in the pipe connection members. If the difference in inner
diameter between the fourth refrigerant pipes and the third refrigerant pipes is
less than 1%, the liquid refrigerant is little accelerated, with the result that rapid
circulation in the cooling plates is not achieved, which is not desirable. If the
15 difference in inner diameter between the fourth refrigerant pipes and the third
refrigerant pipes is greater than 99%, on the other hand, the flow pressure of
the liquid refrigerant is increased and fluid resistance is increased, with the
result that the flow speed of the liquid refrigerant is greatly decreased, which is
also not desirable.
20 In the present invention, as previously described, the fourth refrigerant
pipes may be classified into fourth refrigerant pipes for guiding the liquid
refrigerant to the cooling plates and fourth refrigerant pipes for guiding the
liquid refrigerant from the cooling plates to the pipe connection members.
The fourth refrigerant pipes for guiding the liquid refrigerant to the cooling
14
plates and the fourth refrigerant pipes for guiding the liquid refrigerant from the
cooling plates to the pipe connection members may be different from each
other in terms of size.
Specifically, the fourth refrigerant pipes for guiding the liquid refrigerant
from the cooling plates to the pipe connection members may 5 have a relatively
large inner diameter, which is advantageous in discharging a large amount of
liquid refrigerant from the cooling plates to the pipe connection members.
However, it is not desirable for the inner diameter of the fourth refrigerant pipes
to be equal to the inner diameter of the third refrigerant pipes, since it is
10 advantageous for the flow speed of the liquid refrigerant to be high even in the
above structure. In this case, therefore, each of the fourth refrigerant pipes
may have an inner diameter equivalent to 30% to 99%, and specifically 60% to
99%, of the inner diameter of each of the third refrigerant pipes.
On the other hand, the fourth refrigerant pipes for guiding the liquid
15 refrigerant to the cooling plates may have a relatively small inner diameter in
order to accelerate the liquid refrigerant. For example, each of the fourth
refrigerant pipes may have an inner diameter equivalent to 30% to 99%,
specifically 10% to 90%, and more specifically 50% to 80%, of the inner
diameter of each of the third refrigerant pipes.
20 Each of the connection conduits is inserted into a corresponding one
of the refrigerant pipes in an interference fitting fashion such that the refrigerant
pipes are connected to the connection conduits. For such interference fitting,
each of the refrigerant pipes may have an inner diameter smaller than the
diameter of a corresponding one of the connection conduits. Specifically,
15
each of the refrigerant pipes may have an inner diameter equivalent to 70% to
100% of the diameter of a corresponding one of the connection conduits. In
addition, in this structure, the liquid refrigerant may be accelerated when the
liquid refrigerant flows into the refrigerant pipes through the connection
5 conduits.
If each of the refrigerant pipes has an inner diameter less than 70% of
the diameter of a corresponding one of the connection conduits, the liquid
refrigerant does not smoothly flow to the refrigerant pipes since the inner
diameter of each of the refrigerant pipes is too small. Furthermore,
10 interference fitting is substantially impossible, which is not desirable. If each
of the refrigerant pipes has an inner diameter greater than 100% of the
diameter of a corresponding one of the connection conduits, each of the
refrigerant pipes and a corresponding one of the connection conduits cannot
be securely coupled to each other, which is also not desirable.
15 The refrigerant pipes may be configured to have at least one selected
from between a straight structure and a curved structure.
For example, each of the fourth refrigerant pipes, which are connected
to the cooling plates, may have a curved structure such that the fourth
refrigerant pipes can be flexibly connected to the cooling plates regardless of
20 the positions of the cooling plates. The third refrigerant pipes, which guide the
overall circulation of the liquid refrigerant in the cooling system, may have a
straight structure such that the length of the third refrigerant pipes is minimized.
Each of the straight refrigerant pipes may be made of a rigid plastic
material. For example, the rigid plastic material may be high-strength nylon
16
or polyvinyl chloride, which exhibits high mechanical strength and high
insulation for the liquid refrigerant. However, the present invention is not
limited thereto.
In addition, each of the straight refrigerant pipes may be coupled to a
corresponding one of the pipe connection members as the 5 result of the end of
each of the straight refrigerant pipes wrapping the corresponding one of the
pipe connection members by thermal shrinkage. According to circumstances,
each of the straight refrigerant pipes and a corresponding one of the pipe
connection members may be more securely coupled to each other using a
10 binding member, such as a clamping member.
Each of the curved refrigerant pipes may be made of a flexible rubber
material that is capable of being partially stretched or curved such that the
curved refrigerant pipes can be flexibly connected to the cooling plates.
Specifically, each of the curved refrigerant pipes may be made of ethylene
15 propylene diene monomer (EPDM), which exhibits high elasticity and
mechanical strength.
In addition to the fourth refrigerant pipes, the first refrigerant pipe and
the second refrigerant pipe may be curved so as to flexibly correspond to the
positions of the refrigerant introduction port and the refrigerant discharge port.
20 In addition, each of the curved refrigerant pipes may be securely
coupled to a corresponding one of the pipe connection members as the result
of a clamping member wrapping the end of the curved refrigerant pipe in the
state in which the curved refrigerant pipe is inserted into a corresponding one
of the connection conduits of the pipe connection member.
17
Meanwhile, in a concrete example, each of the cooling plates may be
configured to have a structure in which a first conduit and a second conduit,
which communicate with the hollow flow channel in the cooling plate, protrude
outward from the cooling plate, the first conduit of each of the cooling plates
may be connected to a corresponding one of the fourth refrigerant 5 pipes into
which the liquid refrigerant is introduced, and the second conduit of each of
the cooling plates may be connected to a corresponding one of the fourth
refrigerant pipes from which the liquid refrigerant is discharged.
Each of the cooling plates may include a base plate having a plurality
10 of protrusions formed thereon and a cover plate coupled to the base plate in
the state of being in tight contact with the protrusions for defining a flow
channel in the remaining space of the base plate excluding the protrusions.
Consequently, each of the cooling plates may be configured to have a
structure in which the flow channel, along which the liquid refrigerant flows, is
15 defined in the space in the base plate defined by the protrusions. The base
plate and the cover plate may be fastened to each other using mechanical
fastening members, such as bolts and nuts. In addition, a water-tight
member, made of rubber or silicon, may be provided between the base plate
and the cover plate in order to prevent the leakage of liquid refrigerant from
20 between the base plate and the cover plate.
The protrusions may include first protrusions discontinuously
protruding from one end of the base plate toward the other end of the base
plate and a second protrusion disposed between the first protrusions, the
second protrusion continuously protruding from one end of the base plate
18
toward the other end of the base plate.
A vortex may be generated in the liquid refrigerant between the
discontinuously protruding first protrusions, whereby the flow speed of the
liquid refrigerant may be increased.
In general, cooling speed is proportional to the 5 flow speed of liquid
refrigerant before heat exchange and to the speed at which the liquid
refrigerant is distributed over the area to be cooled. Therefore, it is
advantageous for the liquid refrigerant to rapidly flow and be distributed in the
flow channel defined in each of the cooling plates, in which cooling is
10 performed through actual heat exchange.
In the present invention, as described above, a vortex may be
generated in the liquid refrigerant between the discontinuously protruding first
protrusions, by which the liquid refrigerant is irregularly divided, with the result
that the liquid refrigerant may flow while being more rapidly distributed,
15 thereby increasing the cooling speed of each of the cooling plates and thus
improving the cooling efficiency of each of the cooling plates.
Each of the first protrusions may be generally configured to have a
streamlined structure in order to reduce fluid resistance to the liquid
refrigerant. In addition, the first protrusions may have different sizes and
20 shapes. Alternatively, the first protrusions may have the same size and
shape. In addition, the distributed liquid refrigerant is circulated along the
hollow flow channel while being guided by the continuously protruding second
protrusions.
The base plate may be provided on the surface thereof opposite the
19
surface on which the protrusions are formed with an insulating material, such
as plastic foam or heat-resistant ceramic, in order to prevent the introduction
of heat into the flow channel from the outside, excluding a corresponding one
of the battery modules.
The cover plate may be provided on the 5 surface thereof that is
disposed in tight contact with a corresponding one of the battery modules,
specifically on the surface thereof opposite the surface that faces the base
plate, with a thermal interface material (TIM) pad for accelerating thermal
conduction in order to achieve more efficient thermal conduction between the
10 cover plate and the battery module. The thermal interface material pad
reduces thermal conduction resistance in the state of being in contact with the
battery module.
The thermal interface material pad may be made of thermally
conductive grease, thermally conductive epoxy-based bond, thermally
15 conductive silicone, thermally conductive adhesive tape, or a graphite sheet.
However, the present invention is not limited thereto. Any one of the abovementioned
materials may be used, or two or more of the above-mentioned
materials may be combined.
As described above, each of the cooling plates is configured to have a
20 structure in which heat generated from a corresponding one of the battery
modules is removed by the liquid refrigerant flowing in the cooling plate.
Specifically, each of the cooling plates may be configured such that a
corresponding one of the battery modules is mounted on the cover plate and
such that each of the cooling plates receives heat from a corresponding one of
20
the battery modules and transfers the heat to the liquid refrigerant flowing in the
hollow flow channel, thereby cooling the battery module. Consequently, it is
possible for the cooling plates to cool the battery modules through the abovedescribed
process.
In addition, at least one of the cooling plates 5 may have an area
equivalent to 100% to 300% of the area of each of the other cooling plates,
and the at least one of the cooling plates may be different in size and shape of
the protrusions from the other cooling plates.
The area of each of the cooling plates may correspond to the size of a
10 corresponding one of the battery modules, which is mounted on the cooling
plate. In the cooling system according to the present invention, a plurality of
battery modules having different sizes and shapes may be mounted on cooling
plates having different areas such that the battery modules can be cooled by
the respective cooling plates.
15 In a middle or large-sized battery pack including a plurality of battery
modules, however, the overall performance of the battery pack is reduced if
the performance of some of the battery modules is reduced. One of the main
factors that cause such performance nonuniformity is nonuniformity of cooling
between the battery modules. For this reason, it is necessary for the cooling
20 system to have a structure that is capable of minimizing the temperature
difference between the battery modules.
In the cooling system according to the present invention, therefore, the
flow speed and flow rate of the liquid refrigerant may be set based on the inner
diameters of the connection conduits and the inner diameters of the refrigerant
21
pipes connected to the connection conduits, as described above.
Consequently, the flow speed and flow rate of the liquid refrigerant may be
changed in the cooling plates, which have different cooling areas, whereby the
cooling speed in the cooling plates may be maintained uniform.
In addition, the flow speed and flow rate of the liquid 5 refrigerant in
each of the cooling plates may be changed by varying the size and the shape
of the protrusions.
For example, a cooling plate having a relatively small cooling area
may be configured such that a small number of protrusions are provided and
10 the shape of the protrusions is relatively small. As a result, the liquid
refrigerant may be circulated along the hollow flow channel defined in the
cooling plate at a relatively low flow speed and a relatively low flow rate. On
the other hand, a cooling plate having a relatively large cooling area may be
configured such that a large number of protrusions are provided and the shape
15 of the protrusions is relatively large. As a result, the liquid refrigerant may be
circulated along the hollow flow channel defined in the cooling plate at a
relatively high flow speed and a relatively high flow rate.
The cover plate and the base plate of each of the cooling plates may
be made of a material that exhibits high thermal conductivity. Specifically, the
20 cover plate and the base plate of each of the cooling plates may be made of at
least one selected from among copper, aluminum, tin, nickel, stainless steel,
and thermally conductive polymer. However, the present invention is not
limited thereto.
In brief, the cooling structure of the cooling system according to the
22
present invention is configured such that the liquid refrigerant is circulated
along the third refrigerant pipes, some of the liquid refrigerant in the third
refrigerant pipes is introduced into the cooling plates through the pipe
connection members, cooling is performed in the cooling plates as described
above, and the liquid refrigerant is gathered in the third 5 refrigerant pipes.
More specifically, the liquid refrigerant introduced into the first
refrigerant pipe through the refrigerant introduction port may be divided into
first liquid streams, which flow in the third refrigerant pipes via the pipe
connection members, and second liquid streams, which flow in the fourth
10 refrigerant pipes via the pipe connection members.
The second liquid streams may be introduced into the hollow flow
channels in the cooling plates via the fourth refrigerant pipes and the first
conduits connected to the fourth refrigerant pipes, may flow along the hollow
flow channels, and may be discharged from the cooling plates via the second
15 conduits and the fourth refrigerant pipes connected to the second conduits.
Subsequently, the discharged second liquid streams may be guided to
the pipe connection members via the fourth refrigerant pipes connected to the
second conduits and may be combined with the first liquid streams flowing in
the third refrigerant pipes connected to pipe connection members, and the
20 combined liquid refrigerant may be discharged through the refrigerant
discharge port via the second refrigerant pipe.
In a concrete example, the cooling system may be configured such
that N-1 (N≥3) cooling plates are arranged side by side in the lateral direction
to constitute a cooling plate array, a first cooling plate is disposed in front of the
23
cooling plates so as to correspond to the middle part of the cooling plate array,
and the refrigerant introduction port and the refrigerant discharge port are
arranged side by side in front of the first cooling plate in the state in which the
refrigerant introduction port and the refrigerant discharge port are connected to
the first refrigerant pipe and the second refrigerant p 5 ipe, respectively.
In this case, the first cooling plate and the N-1 (N≥3) cooling plates
may be arranged to have an overall T-shaped structure when viewed from
above.
The refrigerant introduction port and/or the refrigerant discharge port
10 may be provided therein with a temperature sensor for measuring the
temperature of the liquid refrigerant that passes through the refrigerant
introduction port and/or the refrigerant discharge port.
Some of the third refrigerant pipes may be arranged along opposite
sides of the first cooling plate in the state of being connected to the first
15 refrigerant pipe and the second refrigerant pipe via corresponding ones of the
pipe connection members, and the other third refrigerant pipes may be
connected to the third refrigerant pipes that are arranged along the opposite
sides of the first cooling plate via corresponding ones of the pipe connection
members disposed between the first cooling plate and the cooling plate array.
20 The fourth refrigerant pipes may be further connected to the pipe
connection members, and the cooling plates may communicate with the
refrigerant introduction port or the refrigerant discharge port in the state of
being connected to the fourth refrigerant pipes.
In accordance with another aspect of the present invention, there is
24
provided a battery pack including the cooling system with the above-stated
construction, the battery pack including a plurality of battery modules, each of
which includes a plurality of battery cells and which are mounted on the
cooling plates of the cooling system in the state of being in tight contact with
the cooling plates, a bottom housing, on which the battery 5 modules and the
cooling system are mounted, and a top housing coupled to an outer edge of
the bottom housing for isolating the battery modules and the cooling system
from the outside, wherein at least one of the battery modules is different from
the other battery modules in terms of the direction in which the batteries are
10 arranged.
The battery pack according to the present invention includes battery
modules configured to have different battery cell arrangement structures,
whereby it is possible to configure the battery pack such that the battery pack
has various sizes, shapes, and structures. Consequently, it is possible to
15 overcome limitations in installation of the battery pack in a device, such as a
vehicle, and to minimize the ratio of the volume to the capacity of the battery
pack, whereby it is possible to maximize the utilization of the space in the
device. In addition, it is possible to more easily repair or inspect the battery
pack in the limited space.
20 In a concrete example, the battery modules may be classified into a
first battery module assembly and a second battery module assembly, and the
direction in which the battery cells belonging to the first battery module
assembly are arranged may be different from the direction in which the battery
cells belonging to the second battery module assembly are arranged.
25
In other words, the battery modules constituting the battery pack
according to the present invention may be classified into a first battery module
assembly and a second battery module assembly depending on the direction
in which the battery cells constituting the battery modules are arranged.
The first battery module assembly may be mounted 5 on the first cooling
plate and/or the cooling plate located at the middle part of the cooling plate
array, and the second battery module assembly may be mounted on the other
cooling plates of the cooling plate array.
The battery pack is configured to have a structure in which the battery
10 module assemblies are generally arranged in a T shape. Consequently, in
the case in which the battery pack is installed in the central region of a device,
such as a vehicle, when viewed from above, weight may be equally applied to
the left and right sides of the device, whereby it is possible to dynamically
design the device in consideration of the weight applied to the device by the
15 battery pack with greater ease.
In the battery pack according to the present invention, the kind of each
of the battery cells is not particularly restricted. In a concrete example, the
battery cell may be a lithium secondary battery, such as a lithium ion battery or
a lithium ion polymer battery, which exhibits high energy density, discharge
20 voltage, and output stability.
In general, a lithium secondary battery includes a positive electrode, a
negative electrode, a separator, and a non-aqueous electrolytic solution
containing lithium salt.
The positive electrode may be manufactured, for example, by applying
26
a mixture of a positive electrode active material, a conductive agent, and a
binder to a positive electrode current collector and drying the mixture. A filler
may be further added to the mixture as needed.
The positive electrode active material may be, but is not limited to, a
layered compound, such as a lithium cobalt oxide (LiCoO2) 5 or a lithium nickel
oxide (LiNiO2), or a compound replaced by one or more transition metals; a
lithium manganese oxide represented by a chemical formula Li1+xMn2-xO4
(where x = 0 to 0.33) or a lithium manganese oxide, such as LiMnO3, LiMn2O3,
or LiMnO2; a lithium copper oxide (Li2CuO2); a vanadium oxide, such as LiV3O8,
10 LiFe3O4, V2O5, or Cu2V2O7; an Ni-sited lithium nickel oxide represented by a
chemical formula LiNi1-xMxO2 (where M= Co, Mn, Al, Cu, Fe, Mg, B, or Ga, and
x = 0.01 to 0.3); a lithium manganese composite oxide represented by a
chemical formula LiMn2-xMxO2 (where M= Co, Ni, Fe, Cr, Zn, or Ta, and x = 0.01
to 0.1) or a chemical formula Li2Mn3MO8 (where M= Fe, Co, Ni, Cu, or Zn);
15 LiMn2O4 having Li of a chemical formula partially replaced by alkaline earth
metal ions; a disulfide compound; or Fe2(MoO4)3.
The conductive agent is generally added so that the conductive agent
has 1 to 30 weight% based on the total weight of the compound including the
positive electrode active material. The conductive agent is not particularly
20 restricted so long as the conductive agent exhibits high conductivity while the
conductive agent does not induce any chemical change in a battery to which the
conductive agent is applied. For example, graphite, such as natural graphite
or artificial graphite; carbon black, such as carbon black, acetylene black,
Ketjen black, channel black, furnace black, lamp black, or summer black;
27
conductive fiber, such as carbon fiber or metallic fiber; metallic powder, such as
carbon fluoride powder, aluminum powder, or nickel powder; conductive
whisker, such as a zinc oxide or potassium titanate; a conductive metal oxide,
such as a titanium oxide; or conductive materials, such as polyphenylene
derivatives, may be used as 5 the conductive agent.
The binder is a component assisting in binding between the active
material and conductive agent and in binding with the current collector. The
binder is generally added in an amount of 1 to 30 weight% based on the total
weight of the compound including the positive electrode active material. As
10 examples of the binder, there may be used polyvinylidene fluoride, polyvinyl
alcohol, carboxymethylcellulose (CMC), starch, hydroxypropylcellulose,
regenerated cellulose, polyvinyl pyrollidone, tetrafluoroethylene, polyethylene,
polypropylene, ethylene-propylene-diene terpolymer (EPDM), sulfonated
EPDM, styrene butadiene rubber, fluoro rubber, and various copolymers.
15 The filler is an optional component used to inhibit expansion of the
positive electrode. There is no particular limit to the filler so long as it does
not cause chemical changes in a battery to which the filler is applied, and is
made of a fibrous material. As examples of the filler, there may be used
olefin polymers, such as polyethylene and polypropylene; and fibrous
20 materials, such as glass fiber and carbon fiber.
The negative electrode may be manufactured by applying and drying a
negative electrode active material to a negative electrode current collector.
The above-described components may be selectively added to the negative
electrode active material as needed.
28
As the negative electrode active material, for example, there may be
used carbon, such as non-graphitizing carbon or graphite-based carbon; a
metal composite oxide, such as LixFe2O3 (0≤x≤1), LixWO2 (0≤x≤1), SnxMe1-
xMe’yOz (Me: Mn, Fe, Pb, Ge; Me’: Al, B, P, Si, Group 1, 2 and 3 elements of
the periodic table, halogen; 0≤x≤1; 1≤y≤3; 1≤z≤8); a lithium 5 metal; a lithium
alloy; a silicon-based alloy; a tin-based alloy; a metal oxide, such as SnO,
SnO2, PbO, PbO2, Pb2O3, Pb3O4, Sb2O3, Sb2O4, Sb2O5, GeO, GeO2, Bi2O3,
Bi2O4, or Bi2O5; a conductive polymer, such as polyacetylene; or a Li-Co-Ni
based material.
10 The separator is interposed between the positive electrode and the
negative electrode. As the separator, for example, an insulative thin film
exhibiting high ion permeability and high mechanical strength may be used.
The separator generally has a pore diameter of 0.01 to 10 ㎛ and a thickness
of 5 to 300 ㎛. As the material for the separator, for example, a sheet or non15
woven fabric made of olefin polymer, such as polypropylene, which exhibits
chemical resistance and hydrophobicity, glass fiber, or polyethylene is used.
In a case in which a solid electrolyte, such as a polymer, is used as an
electrolyte, the solid electrolyte may also function as the separator.
In addition, in a concrete example, the separator may be an
20 organic/inorganic composite porous safety reinforcing separator (SRS) for
improving the safety of a battery.
The SRS separator may be manufactured by applying inorganic
particles and a binder polymer, as active layer components, to a polyolefin
separator base. In addition to a porous structure included in the separator
29
base, a uniform porous structure may be formed due to interstitial volumes
among the inorganic particles, as the active layer component.
In the case in which the organic/inorganic composite porous separator
is used, it is possible to restrain the increase in thickness of the battery due to
swelling at the time of formation as compared with the case 5 in which a normal
separator is used. In addition, in the case in which a polymer that can gel at
the time of impregnating a liquid electrolytic solution is used as the binder
polymer, the polymer may also be used as an electrolytic.
In addition, the organic/inorganic composite porous separator may
10 exhibit excellent adhesive characteristics by adjusting the contents of the
inorganic particles and the binder polymer, which are active layer components
in the separator. Consequently, a battery assembly process may be easily
carried out.
The inorganic particles are not particularly restricted so long as the
15 inorganic particles are electrochemically stable. That is, the inorganic
particles that can be used in the present invention are not particularly
restricted so long as the inorganic particles are not oxidized and/or reduced
within an operating voltage range (e.g. 0 to 5 V based on Li/Li+) of a battery to
which the inorganic particles are applied. In particular, in the case in which
20 inorganic particles having ion conductivity are used, it is possible to improve
ion conductivity in an electrochemical element, thereby improving the
performance of the battery. Consequently, it is preferable that ion
conductivity of the inorganic particles be as high as possible. In addition, in
the case in which the inorganic particles have high density, it may be difficult
30
to disperse the inorganic particles at the time of coating, and the weight of the
battery may increase. For these reasons, it is preferable that density of the
inorganic particles be as low as possible. Additionally, in the case in which
the inorganic particles have high permittivity, a degree of dissociation of
electrolyte salt, such as lithium salt, in a liquid electrolyte 5 may increase,
thereby improving ion conductivity of the electrolytic solution.
The non-aqueous electrolytic solution containing lithium salt is
composed of a polar organic electrolytic solution and lithium salt. As the
electrolytic solution, a non-aqueous liquid electrolytic solution, an organic solid
10 electrolyte, or an inorganic solid electrolyte may be used.
As examples of the non-aqueous liquid electrolytic solution, mention
may be made of non-protic organic solvents, such as N-methyl-2-pyrollidinone,
propylene carbonate, ethylene carbonate, butylene carbonate, dimethyl
carbonate, diethyl carbonate, gamma-butyro lactone, 1,2-dimethoxy ethane,
15 tetrahydroxy Franc, 2-methyl tetrahydrofuran, dimethylsulfoxide, 1,3-dioxolane,
formamide, dimethylformamide, dioxolane, acetonitrile, nitromethane, methyl
formate, methyl acetate, phosphoric acid triester, trimethoxy methane,
dioxolane derivatives, sulfolane, methyl sulfolane, 1,3-dimethyl-2-
imidazolidinone, propylene carbonate derivatives, tetrahydrofuran derivatives,
20 ether, methyl propionate, and ethyl propionate.
As examples of the organic solid electrolyte, mention may be made of
polyethylene derivatives, polyethylene oxide derivatives, polypropylene oxide
derivatives, phosphoric acid ester polymers, poly agitation lysine, polyester
sulfide, polyvinyl alcohols, polyvinylidene fluoride, and polymers containing ionic
31
dissociation groups.
As examples of the inorganic solid electrolyte, mention may be made of
nitrides, halides, and sulphates of lithium (Li), such as Li3N, LiI, Li5NI2, Li3N-LiILiOH,
LiSiO4, LiSiO4-LiI-LiOH, Li2SiS3, Li4SiO4, Li4SiO4-LiI-LiOH, and Li3PO4-
5 Li2S-SiS2.
The lithium salt is a material that is readily soluble in the abovementioned
non-aqueous electrolyte, and may include, for example, LiCl, LiBr,
LiI, LiClO4, LiBF4, LiB10Cl10, LiPF6, LiCF3SO3, LiCF3CO2, LiAsF6, LiSbF6,
LiAlCl4, CH3SO3Li, CF3SO3Li, (CF3SO2)2NLi, chloroborane lithium, lower
10 aliphatic carboxylic acid lithium, lithium tetraphenyl borate, and imide.
In addition, in order to improve charge and discharge characteristics
and flame retardancy, for example, pyridine, triethylphosphite, triethanolamine,
cyclic ether, ethylenediamine, n-glyme, hexaphosphoric triamide, nitrobenzene
derivatives, sulfur, quinone imine dyes, N-substituted oxazolidinone, N,N15
substituted imidazolidine, ethylene glycol dialkyl ether, ammonium salts, pyrrole,
2-methoxy ethanol, aluminum trichloride, or the like may be added to the nonaqueous
electrolytic solution. According to circumstances, in order to impart
incombustibility, the non-aqueous electrolytic solution may further include
halogen-containing solvents, such as carbon tetrachloride and ethylene
20 trifluoride. Furthermore, in order to improve high-temperature retention
characteristics, the non-aqueous electrolytic solution may further include carbon
dioxide gas.
In accordance with a further aspect of the present invention, there is
provided a device including the battery pack. The device may be any one
32
selected from the group consisting of an electric vehicle, a hybrid electric
vehicle, and a plug-in hybrid electric vehicle.
【Brief Description of Drawings】
The above and other objects, features and other advantages of the
present invention will be more clearly understood from the 5 following detailed
description taken in conjunction with the accompanying drawings, in which:
FIGS. 1 and 2 are perspective views showing a cooling system
according to an embodiment of the present invention;
FIG. 3 is an enlarged view showing a refrigerant introduction port;
10 FIG. 4 is an enlarged view showing the connection between a pipe
connection member and refrigerant pipes;
FIG. 5 is an enlarged view showing the connection between another
pipe connection member and other refrigerant pipes;
FIGS. 6 and 7 are enlarged views showing a cooling plate;
15 FIGS. 8 and 9 are enlarged views showing another cooling plate; and
FIGS. 10 and 11 are perspective views showing a battery pack
according to an embodiment of the present invention.
【Detailed description of the Embodiments】
Now, exemplary embodiments of the present invention will be described
20 in detail with reference to the accompanying drawings. It should be noted,
however, that the scope of the present invention is not limited by the illustrated
embodiments.
33
FIGS. 1 and 2 are perspective views showing a cooling system
according to an embodiment of the present invention, and FIG. 3 is an
enlarged view showing a refrigerant introduction port.
Referring to these figures, the cooling system, denoted by reference
numeral 100, includes a refrigerant introduction port 102, through 5 which liquid
refrigerant is introduced, a refrigerant discharge port 104, through which the
liquid refrigerant is discharged, a plurality of refrigerant pipes 131, 132, 140a,
140b, 142a, 142b, 150a, 150b, 152a, 152b, 154a, 154b, 156a, and 156b
configured to communicate with the refrigerant introduction port 102 and the
10 refrigerant discharge port 104, pipe connection members 160, 162, 164, and
166 configured to interconnect two or more of the refrigerant pipes such that
the refrigerant pipes communicate with each other, and a plurality of cooling
plates 110, 122, 124, and 126, each of which has one surface on which a
corresponding battery module is mounted.
15 In the refrigerant introduction port 102 is mounted a temperature
sensor 170 for measuring the temperature of the liquid refrigerant that passes
through the refrigerant introduction port 102. In the present invention, for
example, water, R-11, R-12, R-22, R-134A, R-407C, or R-410A may be used
as the liquid refrigerant.
20 The cooling plates 110, 122, 124, and 126 include a cooling plate array
120, in which the cooling plates 122, 124, and 126 are arranged side by side in
the lateral direction, and a first cooling plate 110 disposed in front of the cooling
plates 122, 124, and 126 so as to correspond to the middle part of the cooling
plate array 120.
34
Consequently, the cooling plates 110, 122, 124, and 126 are arranged
to have an overall T-shaped structure.
The refrigerant pipes 131, 132, 140a, 140b, 142a, 142b, 150a, 150b,
152a, 152b, 154a, 154b, 156a, and 156b include a first refrigerant pipe 131
connected to the refrigerant introduction port 102, a second 5 refrigerant pipe
132 connected to the refrigerant discharge port 104, a plurality of third
refrigerant pipes 140a, 140b, 142a, and 142b connected to the pipe connection
members 160, 162, 164, and 166, respectively, for guiding the liquid refrigerant
such that the liquid refrigerant flows from the refrigerant introduction port 102
10 to the refrigerant discharge port 104, and a plurality of fourth refrigerant pipes
150a, 150b, 152a, 152b, 154a, 154b, 156a, and 156b connected to the third
refrigerant pipes 140a, 140b, 142a, and 142b via the pipe connection members
160, 162, 164, and 166, the fourth refrigerant pipes 150a, 150b, 152a, 152b,
154a, 154b, 156a, and 156b also being connected to the cooling plates 110,
15 122, 124, and 126.
The refrigerant introduction port 102 and the refrigerant discharge port
104 are arranged side by side in front of the first cooling plate 110 in the state
in which the refrigerant introduction port 102 and the refrigerant discharge port
104 are connected to the first refrigerant pipe 131 and the second refrigerant
20 pipe 132, respectively.
The third refrigerant pipe 140a is connected to the first refrigerant pipe
131 via the pipe connection member 160. The third refrigerant pipe 140b is
connected to the second refrigerant pipe 132 via the pipe connection member
162.
35
The third refrigerant pipes 140a and 140B are arranged along the
opposite sides of the first cooling plate 110.
The third refrigerant pipes 140a and 140B, arranged along the opposite
sides of the first cooling plate 110, are connected respectively to the third
refrigerant pipes 142a and 142B via the pipe connection 5 members 164 and
166, which are disposed between the first cooling plate 110 and the cooling
plate array 120.
That is, in the present invention, the third refrigerant pipes 140a, 140b,
142a, and 142b are connected to the pipe connection members 160, 162, 164,
10 and 166 in order to guide the overall circulation of the liquid refrigerant.
In addition, some of the third refrigerant pipes, i.e. the third refrigerant
pipes 140a and 140B, are connected to the first refrigerant pipe 131 and the
second refrigerant pipe 132, respectively, with the result that the refrigerant
introduction port 102 and the refrigerant discharge port 104 communicate with
15 the third refrigerant pipes 140a, 140b, 142a, and 142b.
The fourth refrigerant pipes 150a, 150b, 152a, 152b, 154a, 154b, 156a,
and 156b are pipes for interconnecting the third refrigerant pipes 140a, 140b,
142a, and 142b, along which the liquid refrigerant is circulated, and the cooling
plates 110, 122, 124, and 126 between the third refrigerant pipes 140a, 140b,
20 142a, and 142b and the cooling plates 110, 122, 124, and 126. A pair of
fourth refrigerant pipes is connected to each of the cooling plates, and a pair of
fourth refrigerant pipes is connected to different third refrigerant pipes.
The liquid refrigerant is introduced into the first cooling plate 110 and is
discharged from the first cooling plate 110 as follows. One selected from
36
between a pair of fourth refrigerant pipes 150a and 150b, i.e. the fourth
refrigerant pipe 150a, guides the liquid refrigerant from the third refrigerant
pipe 140a to the first cooling plate 110, and the other selected from between the
fourth refrigerant pipes 150a and 150b, i.e. the fourth refrigerant pipe 150b,
guides the liquid refrigerant from the first cooling plate 5 110 to the third
refrigerant pipe 140b. The flow of the liquid refrigerant to the other cooling
plates 122, 124, and 126 is the same as the flow of the liquid refrigerant to first
cooling plate 110.
Consequently, the fourth refrigerant pipes 150a and 150b communicate
10 with the third refrigerant pipes 140a, 140b, 142a, and 142b, with the result that
the fourth refrigerant pipes 150a and 150b communicate with the refrigerant
introduction port 102 and the refrigerant discharge port 104, respectively.
The first refrigerant pipe 131 has a larger inner diameter than the third
refrigerant pipe 140a such that a large amount of liquid refrigerant is introduced
15 into the first refrigerant pipe 131 and such that the liquid refrigerant is
accelerated in the third refrigerant pipe 140a. The same equally applies to the
second refrigerant pipe 132.
In addition, the third refrigerant pipes 140a, 140b, 142a, and 142b have
a larger inner diameter than the fourth refrigerant pipes 150a, 150b, 152a,
20 152b, 154a, 154b, 156a, and 156b.
FIGS. 4 and 5 show the structure of the pipe connection members.
For the sake of convenience, the structure in which the pipe connection
members are connected to the first refrigerant pipe 131 and the second
refrigerant pipe 132 will be described by way of example.
37
Referring first to FIG. 4, the pipe connection member 160 includes a
first connection conduit 180, a second connection conduit 182 and a third
connection conduit 184, ends of which are inserted into the refrigerant pipes in
order to interconnect the refrigerant pipes.
The first connection conduit 180 is inserted into 5 one end of the first
refrigerant pipe 131 in an interference fitting fashion.
In addition, the first refrigerant pipe 131 may be securely coupled to the
pipe connection member 160 by a clamping member 192, which is disposed so
as to wrap the end of the first refrigerant pipe 131, in the state in which the first
10 connection conduit 180 of the pipe connection member 160 is inserted into the
end of the first refrigerant pipe 131.
The second connection conduit 182 is inserted into one end of the third
refrigerant pipe 140a in an interference fitting fashion. In this state, the third
refrigerant pipe 140a thermally shrinks such that the end of the third refrigerant
15 pipe 140a wraps the second connection conduit 182. Although not shown in
the figure, the third refrigerant pipe 140a may be more securely coupled to the
pipe connection member 160 by a binding member, such as a clamping
member.
The third connection conduit 184 is inserted into one end of the fourth
20 refrigerant pipe 150a in an interference fitting fashion.
In addition, the fourth refrigerant pipe 150a may be securely coupled to
the pipe connection member 160 by a clamping member 193, which is
disposed so as to wrap the end of the fourth refrigerant pipe 150a, in the state
in which the third connection conduit 184 of the pipe connection member 160 is
38
inserted into the end of the fourth refrigerant pipe 150a.
When the liquid refrigerant reaches the pipe connection member 160
through the first connection conduit 180 via the first refrigerant pipe 131, the
liquid refrigerant is divided and distributed into the second connection conduit
182 and the third connection conduit 184. Specifically, the liquid 5 refrigerant is
divided into a first liquid stream 191, which flows in the third refrigerant pipe
140a, and a second liquid stream 192, which flows in the fourth refrigerant pipe
150a.
In addition, the connection conduits 180, 182, and 184 have different
10 inner diameters. Specifically, the inner diameter of the first connection conduit
180 is greater than the inner diameter of the second connection conduit 182,
and the inner diameter of the second connection conduit 182 is greater than the
inner diameter of the third connection conduit 184.
As a result, the first liquid stream 191, which flows from the first
15 connection conduit 180 to the second connection conduit 182, is accelerated,
and the second liquid stream 192, which flows from the first connection conduit
180 to the third connection conduit 184, is accelerated.
The pipe connection member 162 (see FIG. 5), which is connected to
the second refrigerant pipe 132, has a structure identical to the structure of the
20 pipe connection member 160.
However, the liquid refrigerant flows in the pipe connection member
162, which is connected to the second refrigerant pipe 132, toward the
refrigerant discharge port 104. As a result, a first liquid stream 191a, which
flows in the third refrigerant pipe 140b, and a second liquid stream 192a, which
39
flows in the fourth refrigerant pipe 150b are combined in the pipe connection
member 162. The combined liquid refrigerant is discharged through the
refrigerant discharge port 104 via the second refrigerant pipe 132.
The structure of the pipe connection members 164 and 166 is
substantially identical to the structure of the pipe connection 5 members 160 and
162 except that each of the pipe connection members 164 and 166 has a
different number of connection conduits from the number of the connection
conduits of each of the pipe connection members 160 and 162 so as to
correspond to the number of refrigerant pipes connected to each of the pipe
10 connection members 164 and 166.
In addition, all of the pipe connection members 160, 162, 164, and 166
have the same structure in which the liquid refrigerant is divided and distributed
into the third refrigerant pipe and the fourth refrigerant pipe and the same
structure in which the liquid refrigerant flowing in the third refrigerant pipe and
15 the liquid refrigerant flowing in the fourth refrigerant pipe are combined.
FIGS. 6 and 7 show the cooling plate 124.
Referring to FIGS. 6 and 7, the cooling plate 124 includes a base plate
220 having a plurality of protrusions 222, 224, and 226 formed thereon and a
cover plate 210 coupled to the base plate 220 in the state of being in tight
20 contact with the protrusions 222, 224, and 226 for defining a flow channel 230
in the remaining space of the base plate 220 excluding the protrusions 222,
224, and 226.
That is, the cooling plate 124 is configured to have a structure in which
the flow channel 230, along which the liquid refrigerant flows, is defined in the
40
space in the base plate 220 defined by the protrusions 222, 224, and 226.
The cover plate 210 is provided on the surface thereof that is disposed
in tight contact with a corresponding battery module with a thermal interface
material pad 212 for accelerating thermal conduction in order to achieve more
efficient thermal conduction between the cover plate 5 210 and the battery
module.
The base plate 220 is provided on the surface thereof opposite the
surface on which the protrusions are formed with an insulating material 228 for
preventing the introduction of heat into the flow channel 230 from the outside,
10 excluding the battery module.
In addition, the base plate 220 and the cover plate 210 are fastened to
each other using bolts and nuts.
Meanwhile, the protrusions 222, 224, and 226 include first protrusions
222 and 224, which protrude from one end of the base plate 220 toward the
15 other end of the base plate 220, and a second protrusion 226, which is
disposed between the first protrusions 222 and 224 and which protrudes from
one end of the base plate 220 toward the other end of the base plate 220.
Each of the first protrusions 222 and 224 has a length smaller than the
length of the second protrusion 226. In the present invention, the shape of
20 each of the first protrusions 222 and 224, which separately protrude from the
base plate 220, is defined as a discontinuous shape. On the other hand, the
shape of the second protrusion 226, which extends from one end of the base
plate 220, is defined as a continuous shape.
In the above structure, the liquid refrigerant is irregularly divided by the
41
first protrusions 222 and 224, with the result that the liquid refrigerant is
distributed more rapidly and, at the same time, a vortex is generated in the
region in which the liquid refrigerant is divided, whereby the flow speed of the
liquid refrigerant is increased.
Each of the first protrusions 222 and 224 is generally 5 configured to
have a streamlined structure in order to reduce fluid resistance to the liquid
refrigerant.
The divided and distributed liquid refrigerant flows along the second
protrusion 226, which is longer than each of the first protrusions 222 and 224.
10 The flow direction of the liquid refrigerant is changed by about 180 degrees at
the end of the second protrusion 226.
The above structure has an advantage in that the flow distance of the
liquid refrigerant that flows along the hollow flow channel 230 defined in the
cooling plate 124 is increased, thereby improving cooling efficiency.
15 The cooling plate 124 is configured to have a structure in which a first
conduit 201 and a second conduit 202, which communicate with the hollow
flow channel 230, protrude outward from the cooling plate 124.
The fourth refrigerant pipe 154a, into which the liquid refrigerant is
introduced, is connected to the first conduit 201, and the fourth refrigerant pipe
20 154b, from which the liquid refrigerant is discharged, is connected to the
second conduit 202.
Consequently, the second liquid stream of the liquid refrigerant is
introduced into the hollow flow channel 230 of the cooling plate 124 through
the first conduit 201 via the fourth refrigerant pipe 154a, and performs cooling
42
while flowing along the hollow flow channel 230.
Subsequently, the second liquid stream is discharged from the cooling
plate 124 via the second conduit 202 and the fourth refrigerant pipe 154b,
which is connected to the second conduit 202.
The discharged second liquid stream is guided to 5 the pipe connection
member 164 (see FIG. 2) via the fourth refrigerant pipe 154b, which is
connected to the second conduit 202, and is combined with the first liquid
stream in the third refrigerant pipe 142b (see FIG. 1), which is connected to the
pipe connection member 164. The combined liquid refrigerant may be
10 discharged through the refrigerant discharge port 104 via the second
refrigerant pipe 132.
The cooling and flow processes of the liquid refrigerant in each of the
cooling plates 110, 122, and 126 are identical to those of the liquid refrigerant
in the cooling plate 124.
15 FIGS. 8 and 9 show a cooling plate having a larger cooling area than
the cooling plate shown in FIGS. 6 and 7.
Referring to FIGS. 8 and 9, the cooling plate 122 has a cooling area
equivalent to about 200% of the cooling area of the cooling plate 124 shown in
FIGS. 6 and 7.
20 That is, the cooling plate 122 is similar in basic structure to the cooling
plate 124 shown in FIGS. 6 and 7. However, the size of the cooling plate 122
is different from the size of the cooling plate 124. In addition, as shown in
FIG. 9, the size and shape of protrusions 251 and 252 formed on a base plate
250 are different from the size and shape of the protrusions formed on the
43
base plate of the cooling plate 124 shown in FIGS. 6 and 7.
Specifically, the protrusions 251 and 252 of the cooling plate 122
include first protrusions 251, which discontinuously protrude from one end of
the base plate 250 toward the other end of the base plate 250, and second
protrusions 252, which are disposed between the first protrusions 5 251 and
which continuously protrude from one end of the base plate 250 toward the
other end of the base plate 250.
In the above structure, the liquid refrigerant is divided by the
discontinuously protruding first protrusions 251, and a vortex is generated due
10 to the irregular flow of the liquid refrigerant, thereby increasing the flow speed
of the liquid refrigerant while improving the distribution of the liquid refrigerant.
In the cooling system 100 according to the present invention described
above, the coolant flow channels are defined in the cooling plates, on which
the battery modules are mounted. Compared to the structure in which the
15 coolant flow channels are defined between the battery modules or between
the battery cells, therefore, the cooling system according to the present
invention has a compact structure. In addition, the divided liquid refrigerant is
introduced into the respective cooling plates to independently cool the battery
modules mounted on the respective cooling plates, thereby achieving high
20 cooling uniformity with respect to the battery modules.
Meanwhile, FIG. 10 is a partial perspective view showing a battery
pack according to an embodiment of the present invention including the
cooling system shown in FIGS. 1 to 9, and FIG. 11 is an overall perspective
view of the battery pack according to the embodiment of the present invention.
44
Referring to FIGS. 10 and 11, the battery pack, denoted by reference
numeral 300, includes a cooling system 100, a plurality of battery modules
321, 322, 323, and 324, each of which includes a plurality of battery cells and
which are mounted on cooling plates 110, 122, 124, and 126 of the cooling
system 100 in the state of being in tight contact with the 5 cooling plates 110,
122, 124, and 126, a bottom housing 310, on which the battery modules 321,
322, 323, and 324 and the cooling system 100 are mounted, and a top
housing 390 coupled to the outer edge of the bottom housing 310 for isolating
the battery modules 321, 322, 323, and 324 and the cooling system 100 from
10 the outside.
The bottom housing 310 includes a first bottom housing 311, which is
configured to have a rectangular structure when viewed from above, and a
second bottom housing 312, which is configured to have a rectangular structure
when viewed from above. The second bottom housing 312 is connected to the
15 middle region of a longer side of the outer edge of the first bottom housing 311.
A plurality of first fastening holes 313, through which the bottom
housing 310 is coupled to the top housing 390 using coupling members, and a
plurality of second fastening holes 314, through which the battery pack 300 is
mounted and fixed to a device, are formed in the outer edge of the bottom
20 housing 310.
The battery modules 321, 322, 323, and 324 are classified into a first
battery module assembly 321 and 322 and a second battery module assembly
323 and 324. The direction in which battery cells belonging to the first battery
module assembly 321 and 322 are arranged is different from the direction in
45
which battery cells belonging to the second battery module assembly 323 and
324 are arranged. In addition, the size of each battery module of the first
battery module assembly 321 and 322 is different from the size of each battery
module of the second battery module assembly 323 and 324.
Each battery module of the first battery module assembly 5 321 and 322
includes a single unit module constituted by a plurality of battery cells. One
battery module of the second battery module assembly 323 and 324 includes
three unit modules 323a, 323b, and 323c, which are arranged adjacent to each
other, and the other battery module of the second battery module assembly
10 323 and 324 includes three unit modules 324a, 324b, and 324c, which are
arranged adjacent to each other.
Referring to FIG. 11, the top housing 390 is coupled to the outer edge
of the bottom housing 310 using a plurality of fastening members 315 in the
state in which the battery modules 321, 322, 323, and 324 are mounted in the
15 top housing 390.
The top housing 390 is provided on the outer edge thereof with a
plurality of beads 391 for improving rigidity of the top housing 390.
In various device operating conditions, therefore, it is possible to more
effectively and safely protect the battery modules 321, 322, 323, and 324 in the
20 battery pack 300 against external physical impact or stress.
The top housing 390 is provided at one side surface thereof with a vent
unit 393 for discharging gas from the top housing 390.
The vent unit 393 is configured to have a structure in which each
through hole 393a formed in one surface of the top housing 390 is covered by a
46
micro-porous gas transmission film 393b.
The top housing 390 is provided in a region thereof corresponding to a
manual service device 341 and a fuse box with an opening 392. The manual
service device 341 is exposed outward through the opening 392 of the top
5 housing 390.
At the time of repairing or inspecting the battery pack 300, therefore, it
is possible for a worker to break the electrical connection of the battery pack
300 using the manual service device 341 and the fuse box, which are exposed
through the opening 392 of the top housing 390, without removing the top
10 housing 390 from the battery pack 300. Consequently, it is possible to
effectively prevent the occurrence of an electrical accident, which may occur
when the top housing 390 is removed from the battery pack 300.
Although the exemplary embodiments of the present invention have
been disclosed for illustrative purposes, those skilled in the art will appreciate
15 that various modifications, additions and substitutions are possible, without
departing from the scope and spirit of the invention as disclosed in the
accompanying claims.
【Industrial Applicability】
As is apparent from the above description, in the cooling system
20 according to the present invention, the coolant flow channels are defined in the
cooling plates, on which the battery modules are mounted. Compared to the
structure in which the coolant flow channels are defined between the battery
modules or between the battery cells, therefore, the cooling system according
to the present invention has a compact structure. In addition, the divided
47
liquid refrigerant is introduced into the respective cooling plates to
independently cool the battery modules mounted on the respective cooling
plates, thereby achieving high cooling uniformity with respect to the battery
modules.
In addition, the battery pack according to the 5 present invention
includes battery modules configured to have different battery cell arrangement
structures, whereby it is possible to configure the battery pack such that the
battery pack has various sizes, shapes, and structures. Consequently, it is
possible to overcome limitations in installation of the battery pack in a device,
10 such as a vehicle, and to minimize the ratio of the volume to the capacity of
the battery pack, whereby it is possible to maximize the utilization of space in
the device. In addition, it is possible to more easily repair or inspect the
battery pack in the limited space.

We Claims: -
【Claim 1】
A cooling system for cooling a plurality of battery modules, the cooling
system comprising:
a refrigerant introduction port, through which liquid 5 refrigerant is
introduced, and a refrigerant discharge port, through which the liquid
refrigerant is discharged;
a plurality of refrigerant pipes configured to communicate with the
refrigerant introduction port or the refrigerant discharge port;
10 one or more pipe connection members configured to interconnect two
or more of the refrigerant pipes such that the refrigerant pipes communicate
with each other, the pipe connection members being configured to divide the
liquid refrigerant or to change a flow direction of the liquid refrigerant between
the connected refrigerant pipes; and
15 a plurality of cooling plates, each of which has a hollow flow channel
communicating with at least one of the refrigerant pipes and each of which has
one surface on which a corresponding one of the battery modules is mounted,
the liquid refrigerant being circulated along the hollow flow channel, wherein
the liquid refrigerant is divided by the pipe connection members, the
20 divided liquid refrigerant is supplied to the respective cooling plates, and the
divided liquid refrigerant is combined after being discharged from the
respective cooling plates, whereby the battery modules are cooled by the
respective cooling plates as a result of thermal conduction of the divided liquid
refrigerant.
49
【Claim 2】
The cooling system according to claim 1, wherein the refrigerant pipes
comprise:
a first refrigerant pipe connected to the refrigerant introduction port;
a second refrigerant pipe connected to the refrigerant d 5 ischarge port;
a plurality of third refrigerant pipes disposed between the first
refrigerant pipe and the second refrigerant pipe in a state of being connected
to the respective pipe connection members such that the third refrigerant pipes
communicate with the first refrigerant pipe and the second refrigerant pipe;
10 and
a plurality of fourth refrigerant pipes connected to the third refrigerant
pipes via the pipe connection members, the fourth refrigerant pipes also being
connected to the flow channels defined in the respective cooling plates.
【Claim 3】
15 The cooling system according to claim 2, wherein at least one of the
pipe connection members is connected to at least one of the third refrigerant
pipes and at least one of the fourth refrigerant pipes such that the liquid
refrigerant is divided and distributed into the at least one of the third refrigerant
pipes and the at least one of the fourth refrigerant pipes, thereby adjusting the
20 flow direction of the liquid refrigerant.
【Claim 4】
50
The cooling system according to claim 2, wherein at least one of the
pipe connection members is connected to at least one of the third refrigerant
pipes and at least one of the fourth refrigerant pipes such that liquid refrigerant
divided and distributed into the at least one of the third refrigerant pipes and the
at least one of the fourth refrigerant pipes is combined into 5 a single body of
liquid refrigerant, thereby adjusting a flow rate of the liquid refrigerant.
【Claim 5】
The cooling system according to claim 2, wherein each of the fourth
refrigerant pipes has an inner diameter equivalent to 5% to 99% of an inner
10 diameter of each of the third refrigerant pipes.
【Claim 6】
The cooling system according to claim 2, wherein the first refrigerant
pipe and the second refrigerant pipe each have an inner diameter equivalent
to 101% to 200% of an inner diameter of each of the third refrigerant pipes.
15 【Claim 7】
The cooling system according to claim 2, wherein each of the pipe
connection members comprises n (n≥2) connection conduits for
interconnecting the refrigerant pipes in a state in which ends of the connection
conduits are inserted into the refrigerant pipes, and wherein, when n is equal
20 to or greater than 3, at least one of the connection conduits has an inner
51
diameter equivalent to 5% to 99% of an inner diameter of each of the other
connection conduits.
【Claim 8】
The cooling system according to claim 7, wherein a flow rate of the
liquid refrigerant flowing in the refrigerant pipes is set 5 based on the inner
diameters of the connection conduits and the inner diameters of the refrigerant
pipes connected to the connection conduits.
【Claim 9】
The cooling system according to claim 7, wherein each of the
10 refrigerant pipes connected to the connection conduits has an inner diameter
equivalent to 70% to 100% of a diameter of each of the connection conduits.
【Claim 10】
The cooling system according to claim 1, wherein the refrigerant pipes
are classified into straight refrigerant pipes, each of which is made of a rigid
15 plastic material, and curved refrigerant pipes, each of which is made of a
flexible rubber material.
【Claim 11】
The cooling system according to claim 10, wherein each of the straight
refrigerant pipes is coupled to a corresponding one of the pipe connection
52
members as a result of an end of each of the straight refrigerant pipes
wrapping the corresponding one of the pipe connection members by thermal
shrinkage, and wherein each of the curved refrigerant pipes is coupled to a
corresponding one of the pipe connection members as a result of a clamping
member wrapping an end of the curved 5 refrigerant pipe.
【Claim 12】
The cooling system according to claim 2, wherein
each of the cooling plates is configured to have a structure in which a
first conduit and a second conduit, which communicate with the hollow flow
10 channel in the cooling plate, protrude outward from the cooling plate,
the first conduit of each of the cooling plates is connected to a
corresponding one of the fourth refrigerant pipes into which the liquid
refrigerant is introduced, and
the second conduit of each of the cooling plates is connected to a
15 corresponding one of the fourth refrigerant pipes from which the liquid
refrigerant is discharged.
【Claim 13】
The cooling system according to claim 12, wherein the liquid
refrigerant introduced into the first refrigerant pipe through the refrigerant
20 introduction port is divided into first liquid streams, which flow in the third
refrigerant pipes via the pipe connection members, and second liquid streams,
which flow in the fourth refrigerant pipes via the pipe connection members.
53
【Claim 14】
The cooling system according to claim 13, wherein the second liquid
streams are introduced into the hollow flow channels in the cooling plates via
the fourth refrigerant pipes and the first conduits connected to the fourth
refrigerant pipes, flow along the hollow flow channels, and 5 are discharged from
the cooling plates via the second conduits and the fourth refrigerant pipes
connected to the second conduits.
【Claim 15】
The cooling system according to claim 14, wherein the discharged
10 second liquid streams are guided to the pipe connection members via the
fourth refrigerant pipes connected to the second conduits and are combined
with the first liquid streams flowing in the third refrigerant pipes connected to
pipe connection members, and the combined liquid refrigerant is discharged
through the refrigerant discharge port via the second refrigerant pipe.
15 【Claim 16】
The cooling system according to claim 2, wherein each of the cooling
plates comprises:
a base plate having a plurality of protrusions formed thereon; and
a cover plate coupled to the base plate in a state of being in tight
20 contact with the protrusions for defining a flow channel in a remaining space of
54
the base plate excluding the protrusions.
【Claim 17】
The cooling system according to claim 16, wherein the protrusions
comprise:
first protrusions discontinuously protruding from 5 one end of the base
plate toward the other end of the base plate; and
a second protrusion disposed between the first protrusions, the
second protrusion continuously protruding from one end of the base plate
toward the other end of the base plate, and wherein
10 a vortex is generated in the liquid refrigerant between the
discontinuously protruding first protrusions, whereby a flow speed of the liquid
refrigerant is increased.
【Claim 18】
The cooling system according to claim 16, wherein the base plate is
15 provided on a surface thereof opposite a surface on which the protrusions are
formed with an insulating material.
【Claim 19】
The cooling system according to claim 16, wherein the cover plate is
provided on a surface thereof opposite a surface that faces the base plate with
20 a thermal interface material pad for reducing thermal conduction resistance in
55
a state of being in contact with a corresponding one of the battery modules.
【Claim 20】
The cooling system according to claim 16, wherein each of the cooling
plates is configured such that a corresponding one of the battery modules is
mounted on the cover plate and wherein each of the cooling 5 plates receives
heat from a corresponding one of the battery modules and transfers the heat to
the liquid refrigerant flowing in the hollow flow channel, thereby cooling the
battery module.
【Claim 21】
10 The cooling system according to claim 16, wherein at least one of the
cooling plates has an area equivalent to 100% to 300% of an area of each of
the other cooling plates, and wherein the at least one of the cooling plates is
different in size and shape of the protrusions from the other cooling plates.
【Claim 22】
15 The cooling system according to claim 1, wherein the refrigerant
introduction port and/or the refrigerant discharge port is provided therein with a
temperature sensor for measuring temperature of the liquid refrigerant that
passes through the refrigerant introduction port and/or the refrigerant
discharge port.
56
【Claim 23】
The cooling system according to claim 2, wherein
N-1 (N≥3) cooling plates are arranged side by side in a lateral
direction to constitute a cooling plate array,
a first cooling plate is disposed in front of the cooling 5 plates so as to
correspond to a middle part of the cooling plate array, and
the refrigerant introduction port and the refrigerant discharge port are
arranged side by side in front of the first cooling plate in a state in which the
refrigerant introduction port and the refrigerant discharge port are connected to
10 the first refrigerant pipe and the second refrigerant pipe, respectively.
【Claim 24】
The cooling system according to claim 23, wherein
some of the third refrigerant pipes are arranged along opposite sides of
the first cooling plate in a state of being connected to the first refrigerant pipe
15 and the second refrigerant pipe via corresponding ones of the pipe connection
members, and
the other third refrigerant pipes are connected to the third refrigerant
pipes arranged along the opposite sides of the first cooling plate via
corresponding ones of the pipe connection members disposed between the first
20 cooling plate and the cooling plate array.
【Claim 25】
57
The cooling system according to claim 24, wherein the fourth
refrigerant pipes are further connected to the pipe connection members, and
wherein the cooling plates communicate with the refrigerant introduction port
or the refrigerant discharge port in a state of being connected to the fourth
5 refrigerant pipes.
【Claim 26】
A battery pack comprising the cooling system according to any one of
claims 1 to 25, the battery pack comprising:
a plurality of battery modules, each of which comprises a plurality of
10 battery cells and which are mounted on the cooling plates of the cooling
system in a state of being in tight contact with the cooling plates;
a bottom housing, on which the battery modules and the cooling
system are mounted; and
a top housing coupled to an outer edge of the bottom housing for
15 isolating the battery modules and the cooling system from an outside, wherein
at least one of the battery modules is different from the other battery
modules in terms of a direction in which the batteries are arranged.
【Claim 27】
The battery pack according to claim 26, wherein the battery modules
20 are classified into a first battery module assembly and a second battery
module assembly, and wherein a direction in which battery cells belonging to
the first battery module assembly are arranged is different from a direction in
58
which battery cells belonging to the second battery module assembly are
arranged.
【Claim 28】
The battery pack according to claim 27, wherein
the first battery module assembly is mounted on the 5 first cooling plate
and/or the cooling plate located at the middle part of the cooling plate array,
and
the second battery module assembly is mounted on the other cooling
plates of the cooling plate array.
10 【Claim 29】
A device comprising the battery pack according to claim 26.