TECHNICAL FIELD
The present disclosure relates to a battery pack including two or more battery
modules, and more particularly, to a battery pack having a thermal diffusion prevention
structure for effectively preventing propagation of heat generated from any one battery
10 module to other battery modules in the vicinity.
The present application claims priority to Korean Patent Application No. 10-2020-
0117919 filed on September 14, 2020 in the Republic of Korea, the disclosure of which is
incorporated herein by reference.
15 BACKGROUND ART
A battery that converts electric energy into chemical energy and is repeatedly
chargeable or dischargeable is called a secondary battery, to distinguish the same from a
primary battery which cannot be used again after one use.
Examples of the secondary battery include lithium secondary batteries, nickel20 cadmium (Ni-Cd) batteries, lead storage batteries, nickel-hydrogen (Ni-MH) batteries, zincair batteries, and alkaline manganese batteries. Among them, lead storage batteries and
lithium secondary batteries are the most actively commercialized secondary batteries.
In particular, lithium secondary batteries have advantages such as a high energy
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storage density, a light weight and a compact size, high safety, a low discharge rate, and a
long lifespan, and thus are widely used as a battery for electric vehicles. For reference,
lithium secondary batteries are generally classified into cylindrical, prismatic, and pouch
types according to their manufacturing type, and their uses range from batteries for electric
5 vehicles to batteries for ESS and other electric devices.
Currently, however, it is difficult to obtain sufficient output that allows to drive an
electric vehicle, from a single lithium secondary battery (cell). In order to apply a
secondary battery as an energy supply for an electric vehicle, a battery module in which a
plurality of lithium-ion battery cells are connected in series and/or in parallel is to be
10 configured, and in general, a battery pack is configured, in which the battery modules are
connected in series and which includes a battery management system (BMS) that
functionally retains the battery modules, a cooling system, a battery disconnection unit
(BDU), an electric wiring cable, or the like.
Since secondary batteries involve a chemical reaction during charging and
15 discharging, performance thereof may decrease when the secondary batteries are used in an
environment at a higher temperature than the appropriate temperature, and there is a risk of
ignition or explosion if the temperature rises significantly above the appropriate temperature.
In a battery module having a structure in which the secondary batteries described above are
intensively accommodated in a module housing, heat emitted from the secondary batteries
20 may be summed to increase the temperature of the battery module even more rapidly and
significantly.
Moreover, a battery pack includes a plurality of battery modules, and heat may be
generated due to an abnormal situation occurring in some battery modules or in secondary
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batteries among those secondary batteries constituting the battery module, and the heat may
continuously increase the temperature of the corresponding battery module to be higher than
a certain threshold temperature, causing even other battery modules in the vicinity to
undergo a thermal runaway. If such heat or thermal runaway is not properly controlled, the
5 safety of the battery pack cannot be guaranteed.
DISCLOSURE
Technical Problem
The present disclosure is designed to solve the problems of the related art, and
10 therefore the present disclosure is directed to providing an insulation and heat dissipation
structure for effectively preventing propagation of thermal runaway caused by heat
generated in some battery modules among a plurality of battery modules, to other battery
modules in the vicinity.
However, the technical objectives to be solved by the present disclosure are not
15 limited to the above ones, and other objectives not mentioned herein will be clearly
understood by those skilled in the art from the description of the present disclosure given
below.
Technical Solution
20 In one aspect of the present disclosure, there is provided a battery pack including a
plurality of battery modules including a plurality of battery cells and a module housing
accommodating the plurality of battery cells, a pack case accommodating the plurality of
battery modules, a plurality of insulating materials arranged between two battery modules
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facing each other among the plurality of battery modules, and a thermally conductive sheet
having one side arranged between the insulating materials and the other side provided to be
in contact with the pack case.
The pack case may include a heat transfer material on an inner surface thereof, and
5 the thermally conductive sheet may include a heat dissipating portion having a bent upper
portion to be in surface contact with the inner surface of the pack case.
When the two battery modules facing each other are specified as a first battery
module and a second battery module, the insulating materials may include a first insulation
pad provided to surround one side of the first battery module and a portion of an upper
10 surface thereof, a second insulation pad provided to surround one side of the second battery
module and a portion of an upper surface thereof, and a third insulation pad arranged between
the first insulation pad and the second insulation pad.
The thermally conductive sheet may include a first thermally conductive sheet
arranged between the first insulation pad and the third insulation pad, and a second thermally
15 conductive sheet arranged between the second insulation pad and the third insulation pad.
The first thermally conductive sheet and the second thermally conductive sheet may
be provided in a symmetrical structure to each other.
The first thermally conductive sheet may include a first heat absorbing portion that
is in contact with one surface of the first insulation pad and one surface of the third insulation
20 pad and a first heat dissipating portion that is in contact with an upper surface of the first
insulation pad and the inner surface of the pack case, and the second thermally conductive
sheet may include a second heat absorbing portion that is in contact with one surface of the
second insulation pad and the other surface of the third insulation pad and a second heat
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dissipating portion that is in contact with an upper surface of the second insulation pad and
the inner surface of the pack case.
The thermally conductive sheet may include a material having a thermal
conductivity of 200 W/mk or more.
5 The thermally conductive sheet may include at least one material of aluminum (Al)
and graphite.
The module housing may include a top plate and a bottom plate which respectively
form an upper portion and a lower portion of the module housing and a pair of side plates
respectively forming a left side and a right side of the module housing, and the battery cells
10 may include pouch-type battery cells, and be stacked and arranged such that broad surfaces
of the battery cells are arranged to stand and accommodated such that outermost battery cells
among the battery cells are arranged to face the pair of side plates in the module housing,
and the insulating materials may be arranged in contact with each side plate of the two battery
modules facing each other.
15 The battery pack may further include an anti-compression body that is formed of a
rigid material and penetrates through the insulating materials and the thermally conductive
sheet to be arranged in contact with outer surfaces of the two battery modules with both ends
facing each other.
The anti-compression body may be formed of a cured ceramic fiber.
20 In another aspect of the present disclosure, there is provided an electric vehicle
including the above-described battery pack.
Advantageous Effects
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According to one aspect of the present disclosure, transfer of heat generated from
some battery modules to other battery modules in the vicinity may be prevented or dissipated
to a pack case having a relatively large thermal capacity, thereby effectively preventing
thermal runaway propagation between the battery modules.
5 In detail, according to the present disclosure, when heat is generated from a battery
module, transfer of heat between battery modules may be primarily prevented by using an
insulating material, and a heat source going beyond the primary prevention by the insulating
material may be dissipated to a pack case by using a thermally conductive sheet.
Accordingly, according to this aspect of the present disclosure, thermal runaway propagation
10 between the battery modules may be effectively prevented, thereby further improving the
safety of the battery pack.
The effects of the present disclosure are not limited to the above-described effects,
and effects not mentioned herein will be clearly understood by those of ordinary skill in the
art to which the present disclosure belongs, from the present specification and accompanying
15 drawings.
DESCRIPTION OF DRAWINGS
FIG. 1 is a schematic view of a battery pack in which insulating materials and a
thermally conductive sheet, according to an embodiment of the present disclosure are applied
20 between battery modules.
FIG. 2 illustrates a state in which the insulating materials and the thermally
conductive sheet are separated in some battery modules of FIG. 1.
FIG. 3 is a front view taken from a front side of some battery modules inside a
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battery pack, according to an embodiment of the present disclosure.
FIG. 4 is an enlarged view of region A of FIG. 3.
FIG. 5 is a partial cross-sectional view of a battery pack to illustrate an insulation
and heat dissipation structure between battery modules, according to an embodiment of the
5 present disclosure.
FIG. 6 is an enlarged partial view of FIG. 5.
FIG. 7 is a view for describing an example in which an anti-compression body is
applied to a battery pack according to another embodiment of the present disclosure.
FIG. 8 is an exploded perspective view of insulating materials, a thermally
10 conductive sheet, and an anti-compression body, according to another embodiment of the
present disclosure.
FIG. 9 is a partial cross-sectional view of a battery pack to illustrate an insulation
and heat dissipation structure between battery modules, according to another embodiment of
the present disclosure.
15
BEST MODE
Hereinafter, preferred embodiments of the present disclosure will be described in
detail with reference to the accompanying drawings. Prior to the description, it should be
understood that the terms used in the specification and the appended claims should not be
20 construed as limited to general and dictionary meanings, but interpreted based on the
meanings and concepts corresponding to technical aspects of the present disclosure on the
basis of the principle that the inventor is allowed to define terms appropriately for the best
explanation. Therefore, the configurations disclosed in the preferred embodiments and
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drawings of the present specification are examples of preferred embodiments of the present
disclosure, and thus it should be understood that there can be alternative equivalents or
modification examples that can replace the preferred embodiments at the point of the filing
of the present application.
5 FIG. 1 is a schematic view of a battery pack in which insulating materials and a
thermally conductive sheet, according to an embodiment of the present disclosure are applied
between battery modules. FIG. 2 illustrates a state in which the insulating materials and
the thermally conductive sheet are separated in some battery modules of FIG. 1.
Referring to these drawings, the battery pack according to an embodiment of the
10 present disclosure may be configured to include a plurality of battery modules 100, a
plurality of insulating materials 200, a thermally conductive sheet 300, and a pack case 400.
The battery modules 100 may include a plurality of battery cells 110. While a
secondary battery, specifically, a pouch-type secondary battery is applied as the battery cell
110 according to the present embodiment, the battery module 100 is not necessarily
15 configured as pouch-type secondary batteries. That is, the battery module 100 may be
configured as a cylindrical or prismatic secondary battery.
The secondary battery may include an electrode assembly, an electrolyte, and an
exterior material. The electrode assembly is an assembly of an electrode and a separator,
and may be configured in a form in which one or more positive electrode plates and one or
20 more negative electrode plates are arranged with a separator therebetween. In addition,
each electrode plate of the electrode assembly may be provided with an electrode tab to be
connected to an electrode lead. In particular, in a pouch-type secondary battery, one or
more electrode tabs may be connected to an electrode lead, and the electrode lead may be
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arranged between pouch exterior materials such that one end of the electrode lead is exposed
to the outside, and thus the electrode lead may function as an electrode terminal. The
exterior material may have a hollow space therein to accommodate the electrode assembly
and the electrolyte, and may be configured in a sealed form. The exterior material of a can5 type secondary battery may be formed of a metal material, and the exterior material of a
pouch-type secondary battery may include an external insulating layer, a metal layer, and an
internal adhesive layer.
The configuration of the secondary batteries described above is obvious to those
skilled in the art to which the present disclosure pertains, and thus a detailed description
10 thereof will be omitted. In addition, various secondary batteries known at the time of filing
of the present disclosure may be employed in the battery pack according to the present
disclosure.
The battery module 100 may include a module housing to accommodate the battery
cells 110. The module housing may be regarded to constitute the exterior or an outer
15 surface of the battery module 100, and the plurality of battery cells 110 may be
accommodated in the module housing.
In the present embodiment, the pouch-type battery cells 110 are arranged to stand
and stacked horizontally (±X-axis direction) to be accommodated in the module housing.
In this case, an outermost battery cell 110 in the stacking arrangement may be arranged to
20 face a pair of side plates 123 and 124 to be described later. According to the
accommodation structure of the battery cells 110, the energy density of each battery module
100 may be maximized.
The module housing may be formed in a substantially rectangular parallelepiped
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shape. The module housing may include a top plate 121 and a bottom plate 122
respectively forming an upper portion and a lower portion, and a right side plate 123 and a
left side plate 124 forming a right side and a left side, respectively. In addition, the module
housing may be configured in a form in which front and rear ends are opened, a hollow inner
5 space is formed to accommodate the battery cells 110, and a front cover 125 covering the
front end and a rear cover 126 covering the rear end are included. A module terminal may
be provided on at least one of the front cover 125 and the rear cover 126.
The module housing may be configured in a sealed form to protect the battery cells
110 accommodated therein from external physical and chemical factors. For example, as
10 illustrated in FIG. 1, the module housing may be configured in a form in which top, bottom,
left, right, front, and rear portions thereof are closed to not expose the top, bottom, left, right,
front, and rear portions of the battery cells 110 to the outside. According to the above
configuration, the module housing may be a component forming the outside of one battery
module 100 and function as a boundary dividing the outside of the battery module 100 from
15 the inside of the battery module 100.
The module housing may include a rigid material such as metal, for securing
mechanical rigidity, and an electrically insulating material for securing electrical insulation
outside and inside the battery module 100. Moreover, the module housing may be formed
of other various materials or may further include other materials.
20 The plurality of battery modules 100 may be accommodated in the pack case 400
including a tray 420 and a pack cover 410 provided to be coupled to each other, as illustrated
in FIG. 1. Although not shown for convenience of illustration, a battery management
system (BMS), a cooling system, a battery disconnection unit (BDU), an electric wiring
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cable, and the like may be further accommodated in the pack case 400.
The plurality of battery modules 100 may be arranged horizontally (±X-axis
direction) in a form in which side surfaces thereof face each other in the tray 420. That is,
the plurality of battery modules 100 may be horizontally arranged with the right side plate
5 123 and the left side plate 124 facing each other, respectively.
The insulating material 200 may be arranged between the plurality of battery
modules 100. For example, as illustrated in FIG. 2, the insulating material 200 may be
arranged between every two battery modules 100 facing each other in the entire battery
module 100 included in the battery pack. That is, when N battery modules 100 are included
10 in a battery pack, and the N battery modules 100 are arranged horizontally, N-1 insulating
materials 200 may be arranged between every two battery modules 100.
The insulating material 200 may be formed of a material having high insulation and
heat resistance characteristics. For example, a material such as foamed polystyrene or
phenolic foam may be used to manufacture the insulating material 200. The insulating
15 material 200 may be used to prevent heat generated in the battery module 100 from leaking
to the outside or prevent heat from the outside from flowing into the battery module 100.
Therefore, even when heat is generated from some of the battery modules 100
included in the battery pack, propagation of the heat to other battery modules 100 in the
vicinity may be blocked or considerably delayed.
20 Although the insulating material 200 is formed of a material having a very low
thermal conductivity, it is not that heat conduction does not occur at all, and furthermore,
there is a difference in insulation performance depending on the material or thickness of the
insulating material 200.
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Accordingly, the battery pack according to the present disclosure further includes
the thermally conductive sheet 300 provided between the insulating materials 200.
The thermally conductive sheet 300 includes heat dissipating portions 310b and
320b provided in a form in which a top portion thereof is bent and extended to be in surface
5 contact with an inner surface of the pack case 400, and dissipates heat propagated from any
one battery module 100 over the insulating material 200 to elsewhere with a large thermal
capacity, thereby preventing or further delaying heat propagation to other battery modules
100.
In detail, an example in which the insulating material 200 and the thermally
10 conductive sheet 300 are applied together between the battery modules 100 according to an
embodiment of the present disclosure will be described in detail with reference to FIGS. 3
through 6 together with FIG. 2.
Hereinafter, for convenience of description, two battery modules 100 which are
adjacent to each other and face each other are arbitrarily selected from among the battery
15 modules 100 included in the battery pack, and the left one will be referred to as a first battery
module 100A, and a right one will be referred to as a second battery module 100B.
First, as illustrated in FIG. 2, the insulating material 200 according to the present
embodiment includes a first insulation pad 210, a second insulation pad 220, and a third
insulation pad 230.
20 The first insulation pad 210 may be provided in a form that may surround the entire
right side plate 123 and at least a portion of the top plate 121 of the first battery module
100A, and in a symmetrical structure to the first insulation pad 210, the second insulation
pad 220 may be provided in a form that may surround the entire left side plate 124 and at
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least a portion of the top plate 121 of the second battery module 100B.
In detail, as illustrated in FIGS. 3 through 5, the first insulation pad 210 and the
second insulation pad 220 may respectively include wall portions 210a and 220a formed
with areas respectively corresponding to the side plates 123 and 124 and bent portions 210b
5 and 220b bent at the upper ends of the wall portions 210a and 220a and arranged in parallel
to the top plate 121.
According to the configuration of the wall portions 210a and 220a and the bent
portions 210b and 220b, the inflow and outflow of heat through the entire side plates 123
and 124 and corner areas connected to the side plates 123 and 124 and the top plate 121 may
10 be blocked.
In addition, the bent portions 210b and 220b may be arranged on the top plate 121,
and the bent portions 210b and 220b may be provided to be thicker than the wall portions
210a and 220a. The bent portions 210b and 220b may act as a cushioning material
protecting the battery modules 100 from vibration or impact that may be transmitted from
15 the pack cover 410.
In addition, as the first insulation pad 210 and the second insulation pad 220 are
provided with the bent portions 210b and 220b on the upper portion thereof, when the first
insulation pad 210 and the second insulation pad 220 are arranged between the battery
modules 100, they may be mounted on the upper left portion and the right upper portion of
20 the battery modules 100. This works as an advantage in terms of assembly convenience,
as the above feature allows to place the first insulation pad 210 on the first battery module
100A and the second insulation pad 220 on the second battery module 100B and easily attach
the same to each other.
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The third insulation pad 230 may be provided in a rectangular plate shape and
arranged between the first insulation pad 210 and the second insulation pad 220. The third
insulation pad 230 has a function of blocking heat exchange between a first thermally
conductive sheet 310 and a second thermally conductive sheet 320 to be described later.
5 Referring back to FIGS. 2 through 6, the thermally conductive sheet 300 according
to the present embodiment includes the first thermally conductive sheet 310 and the second
thermally conductive sheet 320, and may include a material having a thermal conductivity
of 200 W/mK or more. As the material of the thermally conductive sheet 300, for example,
aluminum (Al) or graphite may be used. It may be regarded that using graphite, which is a
10 non-metal based material, is advantageous in terms of electrical insulation. However,
aluminum may be used as an alternative to graphite, or graphite and aluminum may be used
in combination

WHAT IS CLAIMED IS:
1. A battery pack comprising:
a plurality of battery modules comprising a plurality of battery cells and a module
5 housing accommodating the plurality of battery cells;
a pack case accommodating the plurality of battery modules;
a plurality of insulating materials arranged between two battery modules facing each
other among the plurality of battery modules; and
a thermally conductive sheet having one side arranged between the insulating
10 materials and the other side provided to be in contact with the pack case.
2. The battery pack of claim 1, wherein the pack case comprises a heat transfer
material on an inner surface thereof, and
the thermally conductive sheet comprises a heat dissipating portion having a bent
15 upper portion to be in surface contact with the inner surface of the pack case.
3. The battery pack of claim 1, wherein when the two battery modules facing
each other are specified as a first battery module and a second battery module,
the insulating materials comprise:
20 a first insulation pad provided to surround one side of the first battery module and a
portion of an upper surface thereof; a second insulation pad provided to surround one side
of the second battery module and a portion of an upper surface thereof; and a third insulation
pad arranged between the first insulation pad and the second insulation pad.
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4. The battery pack of claim 3, wherein the thermally conductive sheet
comprises:
a first thermally conductive sheet arranged between the first insulation pad and the
5 third insulation pad; and
a second thermally conductive sheet arranged between the second insulation pad
and the third insulation pad.
5. The battery pack of claim 4, wherein the first thermally conductive sheet and
10 the second thermally conductive sheet are provided in a symmetrical structure to each other.
6. The battery pack of claim 5, wherein the first thermally conductive sheet
comprises a first heat absorbing portion that is in contact with one surface of the first
insulation pad and one surface of the third insulation pad and a first heat dissipating portion
15 that is in contact with an upper surface of the first insulation pad and the inner surface of the
pack case, and
the second thermally conductive sheet comprises a second heat absorbing portion
that is in contact with one surface of the second insulation pad and the other surface of the
third insulation pad and a second heat dissipating portion that is in contact with an upper
20 surface of the second insulation pad and the inner surface of the pack case.
7. The battery pack of claim 1, wherein the thermally conductive sheet
comprises a material having a thermal conductivity of 200 W/mk or more.
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8. The battery pack of claim 7, wherein the thermally conductive sheet
comprises at least one material of aluminum (Al) and graphite.
5 9. The battery pack of claim 1, wherein the module housing comprises:
a top plate and a bottom plate which respectively form an upper portion and a lower
portion of the module housing; and a pair of side plates respectively forming a left side and
a right side of the module housing,
the battery cells comprise pouch-type battery cells, and are stacked and arranged
10 such that broad surfaces of the battery cells are arranged to stand and accommodated such
that outermost battery cells among the battery cells are arranged to face the pair of side plates
in the module housing, and
the insulating materials are arranged in contact with each side plate of the two
battery modules facing each other.
15
10. The battery pack of claim 1, further comprising an anti-compression body
that is formed of a rigid material and penetrates through the insulating materials and the
thermally conductive sheet to be arranged in contact with outer surfaces of the two battery
modules with both ends facing each other.
20
11. The battery pack of claim 10, wherein the anti-compression body is formed
of a cured ceramic fiber.
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12. A vehicle comprising the battery pack according to any one of claims 1
through 11.