1
FORM 2
THE PATENTS ACT, 1970
(39 of 1970)
&
THE PATENTS RULES, 2003
COMPLETE SPECIFICATION
(See Section 10 and Rule 13)
TITLE OF INVENTION:
BATTERY PACK AND MANUFACTURING METHOD THEREFOR
APPLICANT:
LG CHEM, LTD.
A Company incorporated in South Korea
Having address:
128, Yeoui-daero Yeongdeungpo-gu Seoul 07336
Republic of Korea
The following specification describes the invention and the manner in which it is to
be performed.
2
CROSS-REFERENCE TO RELATED APPLICATIONS AND PRIORITY
The present application claims priority from PCT application Number
PCT/KR2016/004481 filed on April 28, 2016 further claims priority from Korean
Patent Application No. 10-2015-0061977 filed on April 30, 2015 in the Republic of
5 Korea.
TECHNICAL FIELD
The present disclosure relates to a battery including at least one secondary cell, and
more particularly, to a battery pack having improved energy density, assemblability,
and durability, an automobile including the battery pack, and a method of
10 manufacturing the battery pack.
BACKGROUND ART
Examples of currently commercialized secondary cells include nickel-cadmium cells,
nickel-metal hydride cells, nickel-zinc cells, and lithium secondary cells. Among
15 such various secondary cells, lithium secondary cells are freely rechargeable
because of having substantially no memory effect compared with nickel-based
secondary cells, and have a very low self-discharge rate and high energy density.
Owing to these merits, there has been high interest in lithium secondary cells.
In general, lithium secondary cells use a lithium-based oxide as a positive electrode
20 active material and a carbonaceous material as a negative electrode active material.
A lithium secondary cell may include: an electrode assembly in which a positive
electrode plate coated with such a positive electrode active material and a negative
electrode plate coated with such a negative electrode active material are disposed
with a separator therebetween; and a case, that is, a cell case in which the electrode
25 assembly and an electrolytic solution are sealed.
In general, according to case types, lithium secondary cells may be classified into a
can type in which an electrode assembly is accommodated in a metal can, and a
pouch type in which an electrode assembly is accommodated in a pouch formed of
3
an aluminum laminate sheet.
In recent years, secondary cells have been widely used not only in small-sized
devices such as portable electronic devices, but also in medium to large-sized
devices such as automobiles or power storage devices. For use in such medium to
large-sized devices, a large number of secondary cells 5 may be electrically connected
to increase capacity and output power. In particular, pouch-type secondary cells
are widely used in medium to large-sized devices owing to merits such as lightness
and ease of stacking.
In the related art, when a battery pack is constructed by stacking a plurality of
10 pouch-type secondary cells to form a cell assembly and accommodating the cell
assembly in a pack case, end plates may be provided on both the outermost sides of
the cell assembly in the stacking direction of the pouch-type secondary cells. In
general, such end plates are formed of a metallic material and have a function of
protecting and fixing secondary cells and cartridges and maintaining surface
15 pressure.
However, in such a battery pack structure of the related art, it is necessary to fix a
cell assembly and a pack case to each other in addition to fixing end plates to the
cell assembly. Typically, the cell assembly may be fixed by using fastening
members such as bolts and nuts between the pack case and the end plates of the cell
20 assembly. In this case, additional spaces are necessary in the pack case and the end
plates for such fastening members. In addition, it may be necessary to form or
prepare an additional space in the pack case for a process of fastening the cell
assembly to the pack case. However, since these spaces are not used to
accommodate secondary cells, the energy density of the battery pack may be
25 decreased, and the structure of the battery pack may be complicated.
In addition, the structure in which the end plates and the pack case are fixed using
fastening members may not be effective in stably maintaining a fixed state of the
cell assembly in the pack case because the fastening members may become loose as
the battery pack is exposed to vibrations or impacts during use. This may cause
4
breakage or damage of various components included in the battery pack, and thus
the battery pack may malfunction or break down.
Furthermore, the battery pack structure of the related art makes it difficult to
assemble the end plates and the pack case and requires the use of additional
fastening members for coupling the end plates 5 and the pack case, and a process of
previously placing such fastening members on the pack case is not easy to perform,
thereby decreasing productivity and increasing manufacturing costs.
Furthermore, in general, pack cases of battery packs accommodating cell assemblies
are formed of a plastic material, and are thus vulnerable to impacts or the like
10 because of low rigidity.
DISCLOSURE
Technical Problem
The present disclosure is designed to solve the problems of the related art, and
therefore the present disclosure is directed to providing a battery pack having
15 improved assemblability, processability, and productivity, and configured to reduce
manufacturing costs and enhance the sealability and durability of a pack case, and
providing a method of manufacturing the battery pack and an automobile including
the battery pack.
These and other objects and advantages of the present disclosure may be understood
20 from the following detailed description and will become more fully apparent from
the exemplary embodiments of the present disclosure. Also, it will be easily
understood that the objects and advantages of the present disclosure may be realized
by the means shown in the appended claims and combinations thereof.
Technical Solution
25 To achieve the objectives, the present disclosure provides a battery pack including: a
cell assembly including a plurality of secondary cells and a plurality of cartridges,
the cartridges being configured to be stacked on one another and to accommodate
5
the secondary cells while surrounding outer circumferential portions of the
secondary cells from outsides of the secondary cells; a lower housing having an
empty inner space to accommodate the cell assembly in the inner space, the lower
housing being opened on an upper side thereof; a lower end plate including a plateshaped
metallic material and placed in surface 5 contact with a lower surface of the
lower housing; and a lower cover placed on a lower portion of the lower end plate to
cover the lower end plate, the lower cover being fixedly coupled to the lower
housing.
Here, the lower cover may be fixedly coupled to the lower housing by a laser
10 welding method.
Furthermore, the lower cover and the lower housing may include the same plastic
material.
Furthermore, the lower cover may be fixedly coupled to the lower housing along
and outside an edge of the lower end plate.
15 Furthermore, at least one opening may be formed in a center portion of the lower
end plate, and the lower cover may be fixedly coupled to the lower housing through
the opening.
Furthermore, the lower housing and the lower cover may include concave and
convex portions corresponding to each other.
20 Furthermore, the lower end plate may include at least one bolt protruding upward,
and at least one through-hole may be formed in the lower housing to pass the bolt
through the through-hole.
Furthermore, at least one insertion hole may be formed in the cell assembly, and the
bolt may be inserted in the insertion hole.
25 Furthermore, the secondary cells and the cartridges of the cell assembly may be
vertically stacked, and a lowermost cartridge of the cell assembly may be placed in
the inner space of the lower housing in contact with a bottom surface of the lower
6
housing.
Furthermore, the battery pack may further include an upper end plate including a
plate-shaped metallic material and provided on an upper portion of the cell assembly
to cover the upper portion of the cell assembly.
Furthermore, the battery pack may further 5 include an upper housing coupled to the
opened upper side of the lower housing to seal the opened upper side.
Furthermore, in addition, to achieve the objectives, the present disclosure provides
an automobile including the battery pack.
In addition, to achieve the objectives, the present disclosure provides a method of
10 manufacturing a battery pack, the method including: placing a lower end plate
including a plate-shaped metallic material on a lower portion of a lower housing
including an empty inner space and an opened upper side such that the lower end
plate makes surface contact with the lower portion of the lower housing; placing a
lower cover on a lower portion of the lower end plate to cover the lower end plate;
15 fixedly coupling the lower cover and the lower housing to each other; and stacking
secondary cells and cartridges in the inner space of the lower housing, the cartridges
accommodating the secondary cells while surrounding outer circumferential
portions of the secondary cells from outsides of the secondary cells.
Here, in the fixedly coupling of the lower cover and the lower housing to each other,
20 the lower cover and the lower housing may be fixedly coupled to each other by a
laser welding method.
Furthermore, the lower end plate may include at least one bolt protruding upward,
and the lower housing may include at least one through-hole, and in the placing of
the lower end plate, the bolt of the lower end plate may be passed through the
25 through-hole of the lower housing.
Furthermore, at least one insertion hole may be formed in each of the cartridges, and
in the stacking of the secondary cells and the cartridges, the bolt of the lower end
7
plate may be inserted into the insertion holes of the cartridges.
Advantageous Effects
According to an aspect of the present disclosure, the lower end plate and the pack
case do not require an additional 5 structure for coupling the lower end plate to the
pack case for protecting the cell assembly and ensuring the rigidity of the cell
assembly.
Therefore, according to this aspect of the present disclosure, the assemblability and
processability of the battery pack may be improved, and since the number of
10 components of the battery pack is reduced, the manufacturing costs and time of the
battery pack may be decreased. In addition, according to this aspect of the present
disclosure, spaces such as a space for a coupling structure between the lower end
plate and the pack case and a work space for the coupling structure are not required
in the pack case. Therefore, the spatial efficiency of the battery pack may be
15 increased, and unnecessary spaces may be removed from the inside of the battery
pack, thereby improving the energy density of the battery pack and reducing the size
of the battery pack.
In addition, according to an aspect of the present disclosure, the coupling between
the lower end plate and the pack case may not be released or loosened, and thus the
20 cell assembly may be stably fixed inside the pack case. Therefore, breakage or
malfunction of the battery pack may not be caused due to relative movement of the
cell assembly.
According to an aspect of the present disclosure, since the lower end plate is
provided in the pack case, particularly between the lower housing and the lower
25 cover, the rigidity of the pack case may be improved. Therefore, according to this
aspect of the present disclosure, even when the pack case is impacted, the pack case,
particularly the lower housing, may not be broken, and thus components of the
battery pack placed inside the lower housing, such as the cell assembly or other
8
electric components, may be safely protected.
In addition, according to an aspect of the present disclosure, the sealability of the
pack case may be improved owing to the lower end plate placed in the pack case.
For example, even if the lower cover is somewhat damaged by an impact applied to
the pack case, permeation of foreign substances 5 such as moisture, nail-shaped parts,
or stones into the lower housing may be prevented owing to the lower end plate. In
particular, when the battery pack is used in an electric vehicle, the possibility of
permeation of foreign substances may be high. However, according to this aspect
of the present disclosure, the durability of the battery pack may be guaranteed.
10
DESCRIPTION OF DRAWINGS
The accompanying drawings illustrate preferred embodiments of the present
disclosure and together with the foregoing disclosure, serve to provide further
understanding of the technical features of the present disclosure, and thus, the
15 present disclosure is not construed as being limited to the drawings.
FIG. 1 is a perspective view schematically illustrating an assembled state of a
battery pack according to an embodiment of the present disclosure.
FIG. 2 is an exploded perspective view illustrating the battery pack of FIG. 1.
FIG. 3 is a perspective view schematically illustrating a configuration of cartridges
20 and secondary cells according to an embodiment of the present disclosure.
FIG. 4 is a perspective view schematically illustrating an assembly of a lower cover
and a lower housing.
FIG. 5 is a cross-sectional view taken along line A1-A1' of FIG. 4.
FIG. 6 is a bottom view of the assembly shown in FIG. 4.
25 FIG. 7 is an exploded perspective view schematically illustrating a configuration of
9
a battery pack according to an embodiment of the present disclosure.
FIG. 8 is an assembled perspective view illustrating the battery pack shown in FIG.
7.
FIG. 9 is a flowchart schematically illustrating a method of manufacturing a battery
5 pack according to an embodiment of the present disclosure.
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
10 should be understood that the terms used in the specification and the appended
claims should not be 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.
15 Therefore, the description proposed herein is just a preferable example for the
purpose of illustrations only, not intended to limit the scope of the disclosure, so it
should be understood that other equivalents and modifications could be made
thereto without departing from the scope of the disclosure.
FIG. 1 is a perspective view schematically illustrating an assembled state of a
20 battery pack according to an embodiment of the present disclosure. In addition,
FIG. 2 is an exploded perspective view illustrating the battery pack of FIG. 1.
Referring to FIGS. 1 and 2, the battery pack of the present disclosure includes a cell
assembly 100, a lower housing 200, a lower end plate 300, and a lower cover 400.
The cell assembly 100 may include a plurality of secondary cells and a plurality of
25 cartridges.
Here, the secondary cells are components for storing or discharging electrical energy
10
through charging and discharging operation steps. In particular, the secondary
cells may be pouch-type secondary cells. Each of the secondary cells may include
an electrode assembly, an electrolyte, and a pouch-type case. In addition, the
secondary cells of the present disclosure may be lithium secondary cells.
The electrode assembly may be formed by arranging 5 at least one positive electrode
plate and at least one negative electrode plate with a separator therebetween. More
specifically, examples of the electrode assembly includes a wound-type electrode
assembly in which one positive electrode plate and one negative electrode plate are
wound together with a separator, and a stacked-type electrode assembly in which a
10 plurality of positive electrode plates and a plurality of negative electrode plates are
alternately stacked with separators therebetween .
In addition, the pouch-type case may include an external insulating layer, a metal
layer, and an internal adhesive layer. The pouch-type case may include a thin
metal film such as a thin aluminum film for protecting internal components such as
15 the electrode assembly and the electrolyte, complementing the electrochemical
properties of the electrode assembly and the electrolyte, and guaranteeing heat
dissipation. In addition, the thin aluminum film may be placed between insulating
layers formed of an insulating material, that is, between the external insulating layer
and the internal adhesive layer, so as to electrically insulate internal components of
20 the secondary cell such as the electrode assembly and the electrolyte from other
components located outside the secondary cell.
In particular, the pouch-type case may include two pouches, and a concave inner
space may be formed in at least one of the two pouches. The electrode assembly
may be accommodated in the inner space of the pouch. In addition, sealing
25 portions may be provided on peripheral surfaces of the two pouches, and these
sealing portions may be fused to each other to seal the inner space in which the
electrode assembly is accommodated.
In addition, the electrode plates of the electrode assembly may be provided with
electrode tabs, respectively, and at least one of the electrode tabs may be connected
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to an electrode lead. In addition, the electrode lead may be disposed between the
sealing portions of the two pouches and exposed to the outside of the pouch-type
case, and thus the electrode lead may function as an electrode terminal of the
secondary cell.
According to an aspect of the present disclosure, the 5 cell assembly 100 may include
various pouch-type secondary cells known at the time of filing the present
application.
The plurality of secondary cells may be included in the battery pack. In particular,
the plurality of secondary cells may be vertically arranged in a lying position such
10 that relatively large surfaces of the secondary cells may face upward and downward.
The cartridges may accommodate the secondary cells in inner spaces thereof. In
particular, the cartridges may be configured to surround outer circumferential
portions of the secondary cells from the outsides of the secondary cells.
FIG. 3 is a perspective view schematically illustrating a configuration of cartridges
15 120 and secondary cells 110 according to an embodiment of the present disclosure.
Referring to FIG. 3, each of the cartridges 120 may include a main frame 121
having a substantially tetragonal ring shape. In this case, the main frame 121 of
the cartridge 120 may include four unit frames connected to each other at both ends
thereof. The unit frames of the cartridge 120 may be separately manufactured and
20 then assembled together, or may be manufactured in one piece from the beginning.
In particular, the secondary cells 110 may be pouch-type secondary cells having a
substantially tetragonal shape. In the present embodiment, the main frames 121
may have a tetragonal ring shape as described above, and thus the secondary cells
110 may be placed in center empty spaces of the main frames 121 so as to surround
25 edge portions of the secondary cells 110 from the outside. Therefore, the
cartridges 120 may accommodate the secondary cells 110 and protect outer sides of
the secondary cell 110.
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In addition, each of the cartridges 120 may include a cooling plate 122 formed of a
thermally conductive material and located in a center region thereof. For example,
the cooling plate 122 of the cartridge 120 may be formed of aluminum and located
in a center region of a tetragonal ring defined by the main frame 121. In this case,
each of the cartridges 120 may 5 include two cooling plates 122, that is, an upper plate
and a lower plate that are spaced a predetermined distance from each other in a
vertical direction. A flow path P may be formed between the two cooling plates
122 to allow a coolant such as air to flow along the flow path P. In the this
cartridge structure, a secondary cell 110 may be placed on an upper side of the upper
10 plate, and another secondary cell 110 may be placed on a lower side of the lower
plate. In this case, it may be considered that one cartridge 120 accommodates two
secondary cells 110. Heat generated from a secondary cell 110 may be transferred
to an adjacent cooling plate 122 and dissipated to the outside by the coolant flowing
along the flow path P between the cooling plates 122.
15 In addition, the cartridges 120 may be configured to be placed one on top of another.
In particular, the plurality of cartridges 120 included in the battery pack may be
stacked in a vertical direction as shown in FIG 3. In this case, stacking surfaces of
the cartridges 120, for example, upper and lower surfaces of the main frames 121,
may have concave and convex structures corresponding to each other. In this case,
20 owing to the concave and convex structures of the cartridges 120, the cartridges 120
may be more reliably coupled to and fixed to each other, and it may be easy to
assemble the cartridges 120 because the concave and convex structures function as
guides.
As described above, the cartridges 120 may accommodate pouch-type secondary
25 cells 110 in inner spaces formed as the cartridges 120 are stacked, thereby limiting
exposure of the secondary cells 110 to protect the secondary cells 110 from external
physical or chemical agents, guiding arrangement of the secondary cells 110, and
preventing relative movement of a stack of the secondary cells 110.
In addition, each of the cartridges 120 may include a coupling hole formed in at
30 least one side thereof. For example, as indicated by H1 in FIG. 3, each of the
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cartridges 120 may include a coupling hole vertically formed through at least one of
the four unit frames or in a corner at which two unit frames meet each other.
The lower housing 200 may have an empty inner space therein to accommodate the
cell assembly 100. In addition, the lower housing 200 may have an opened upper
side, and the cell assembly 100 may 5 be inserted into the inner space through the
opened upper side. That is, the lower housing 200 may have an inner space closed
on bottom and lateral sides thereof and opened on an upper side thereof.
The lower housing 200 may include a plastic material. The plastic material is easy
to shape, light in weight, and highly electrically insulative, thereby improving the
10 productivity of the battery pack, reducing the weight of the battery pack, and
guaranteeing insulation of the battery pack.
As shown in FIG. 2, the lower end plate 300 may have a plate shape, that is, a wide
plate shape. In addition, the lower end plate 300 may include a metallic material
having rigidity. For example, the lower end plate 300 may be a rectangular plate
15 formed of steel.
In particular, in the battery pack of the present disclosure, the lower end plate 300
may be placed on a lower portion of the lower housing 200. That is, the lower end
plate 300 may be placed on the lower portion of the lower housing 200 in a state in
which the lower end plate 300 is laid in parallel to the ground, and an upper surface
20 of the lower end plate 300 may be directly brought into contact with a lower surface
of the lower housing 200.
The lower cover 400 may have a plate shape and placed on a lower portion of the
lower end plate 300 to cover the lower end plate 300. For example, the lower
cover 400 may have a larger area than a surface area of the lower end plate 300 such
25 that a lower surface of the lower end plate 300 may not be exposed to the outside.
In addition, like the lower housing 200, the lower cover 400 may include a plastic
material.
In particular, the lower cover 400 may be coupled to the lower housing 200.
14
FIG. 4 is a perspective view schematically illustrating an assembly of the lower
cover 400 and the lower housing 200. In addition, FIG. 5 is a cross-sectional view
taken along line A1-A1' of FIG. 4, and FIG. 6 is a bottom view of the assembly
shown in FIG. 4.
Referring to FIGS. 4 to 6, at least a portion of 5 the lower cover 400 may be coupled
to the lower housing 200 to fix the lower cover 400 to the lower housing 200. In
this case, the lower end plate 300 may be placed between the lower cover 400 and
the lower housing 200. That is, the lower end plate 300 may be placed between the
lower cover 400 and the lower housing 200 that are coupled to each other, and thus,
10 on the whole, the lower end plate 300 may not be exposed to the outside. In this
case, it may be considered that a pack case of the battery pack of the present
disclosure includes the lower housing 200, the lower end plate 300, and the lower
cover 400.
In particular, the lower cover 400 and the lower housing 200 may include a polymer
15 material such as a plastic material, and the lower end plate 300 may include a
metallic material.
In this case, it may be said that the pack case is configured by embedding a metal
plate in a main body formed of a plastic material. According to this configuration
of the present disclosure, the pack case is mainly formed of a polymer material, and
20 thus characteristics such as electrical insulation, lightness, and formability may be
guaranteed. In addition, since the rigidity of the pack case is improved owing to
the metallic lower end plate 300 embedded in the pack case, the pack case may not
be easily broken by an external impact or the like, and thus other components placed
inside the battery pack may be protected. In addition, owing to the lower end plate
25 300 formed of a metallic material and embedded in the pack case, the sealability of
the pack case may be improved, and thus moisture or foreign substances such as a
nail-shaped part may not be introduced through the pack case.
Preferably, the lower cover 400 may be fixedly coupled to the lower housing 200 by
a laser welding method. For example, the lower cover 400 may be fused to the
15
lower housing 200 by irradiating contact portions of the lower cover 400 and the
lower housing 200 with a laser beam. In this case, the lower cover 400 may
transmit a laser beam, and the lower housing 200 may absorb the laser beam.
In the case of laser welding, the intensity of welding is controllable, and fine area
welding is possible by focusing a laser beam on a 5 very small area and transferring
energy to the very small area. In addition, thermal deformation or property
deterioration of workpieces, that is, the lower cover 400 and the lower housing 200
may occur to a small extent. According to the present disclosure, the lower cover
400 and the lower housing 200 of the battery pack may be coupled to each other by
10 various laser welding methods known at the time of filing the present application
such as a CO2 laser welding method or a YAG laser welding method.
In particular, the lower cover 400 and the lower housing 200 may include the same
plastic material. According to this aspect of the present disclosure, the lower
housing 200 and the lower cover 400 may be laser-welded to each other with
15 improved weldability, and thus the coupling strength between the lower housing 200
and the lower cover 400 may be stably maintained.
As described above, the lower cover 400 may be directly brought into contact with
the lower housing 200 and fixedly coupled to the lower housing 200 by a laser
welding method or the like.
20 In particular, the lower cover 400 may be fixedly coupled to the lower housing 200
along and outside an edge of the lower end plate 300. For example, the lower
cover 400 may be welded to the lower housing 200 by irradiating outer
circumferential portions indicated by L1 in FIGS. 5 and 6 with a laser beam. In
this case, the shape of the portions welded with a laser beam may have an
25 approximately rectangular shape.
Since the lower end plate 300 is placed between the lower cover 400 and the lower
housing 200, the lower cover 400 and the lower housing 200 may be directly
coupled to each other through portions on which the lower end plate 300 is not
placed. That is, the lower cover 400 may be directly brought into contact with the
16
lower housing 200 and welded to the lower housing 200 along and outside the edge
of the lower end plate 300 as indicated by L1 in FIG. 5. To easily achieve this
structure, the lower cover 400 may have a horizontal surface area similar to a lower
surface area of the lower housing 200 but larger than the lower end plate 300. That
is, the lower end plate 300 may have a horizontal surface 5 area slightly smaller than
those of the lower housing 200 and the lower cover 400. Then, owing to this size
difference, an outer circumferential portion of the lower cover 400 may be coupled
to the lower housing 200.
In addition to the outer circumferential portion of the lower cover 400, another
10 portion of the lower cover 400 may be fixedly coupled to the lower housing 200.
For example, the lower cover 400 may be directly welded to the lower housing 200
by irradiating center portions indicated by L2 in FIGS. 5 and 6 with a laser beam.
In this configuration of the present disclosure, since the lower cover 400 is coupled
to the lower housing 200 in a center region by a method such as a laser welding
15 method, the coupling strength between the lower cover 400 and the lower housing
200 may be stably maintained. In particular, according to this configuration of the
present disclosure, the center region of the lower cover 400 may not be separated
away from the lower end plate 300 or the lower housing 200.
In particular, the lower cover 400 and the lower housing 200 may have a rectangular
20 shape when viewed from below. In this case, the lower cover 400 may be welded
to the lower housing 200 in zones shaped like rods extending in parallel to long
sides of the lower cover 400. Two or more such rod-shaped weld zones may be
spaced apart from each other by a predetermined distance in a short-side direction of
the lower cover 400 and a predetermined distance in a long-side direction of the
25 lower cover 400.
According to this configuration of the present disclosure, a laser welding process
may be easily performed, and fixing strength by the laser welding process may be
stably maintained.
According to this configuration, center portions of the lower cover 400 and the
17
lower housing 200 are directly brought into contact with and coupled to each other,
and thus the lower end plate 300 placed between the lower cover 400 and the lower
housing 200 may have openings at positions corresponding to the coupling portions.
For example, as indicated by O in FIG. 2 and FIG. 6, a plurality of openings may be
vertically formed through center 5 portions of the lower end plate 300. In addition,
the lower cover 400 may be directly brought into contact with the lower housing 200
through the openings O of the lower end plate 300 and may be coupled to the lower
housing 200 by a method such as a welding method.
In the above embodiment, the case of coupling the lower cover 400 and the lower
10 housing 200 to each other by a laser welding method is mainly described.
However, this coupling method is not a limiting example. That is, the lower cover
400 and the lower housing 200 may be fixedly coupled to each other by a method
other than a laser welding method. For example, the lower cover 400 and the
lower housing 200 may be formed by an insert injection molding method. That is,
15 injection molding may be performed by inserting the metallic lower end plate 300
into a polymer material for forming the lower cover 400 and the lower housing 200,
and thus a structure in which the lower cover 400 and the lower housing 200
surround the lower end plate 300 may be obtained. In another example, the lower
cover 400 may be formed by an over-molding method. That is, in a state in which
20 the lower end plate 300 is mounted on the lower portion of the lower housing 200,
the lower cover 400 may be molded on the lower portion of the lower end plate 300,
and thus the lower end plate 300 may be placed between the lower housing 200 and
the lower cover 400.
In addition, preferably, the lower housing 200 and the lower cover 400 may have
25 concave and convex portions corresponding to each other.
For example, as indicated by L1 in FIG. 5, the lower housing 200 may include a
concave portion recessed in an upward direction, and the lower cover 400 may
include a convex portion protruding in the upward direction. In this case, the
convex portion of the lower cover 400 may be formed in a ring shape along the
30 outer circumferential portion of the lower cover 400. In addition, as indicated by
18
L2 in FIG. 5, the lower housing 200 may include convex portions protruding in a
downward direction, and the lower cover 400 may include concave portions
recessed in the downward direction. In this case, the positions and shapes of the
convex and concave portions may correspond to each other. When the lower cover
400 is placed below the lower housing 5 200 and the lower end plate 300, the convex
portions may be inserted into the concave portions corresponding thereto.
According to this configuration of the present disclosure, the coupling position of
the lower cover 400 may be easily determined with respect to the lower housing 200,
and thus the lower housing 200 and the lower cover 400 may be easily assembled.
10 In addition, the concave and convex portions may reduce horizontal relative
movement of the lower housing 200 and the lower cover 400 during a coupling
process such as a welding process, and thus the lower housing 200 and the lower
cover 400 may be easily coupled to each other with high reliability, thereby
guaranteeing stable coupling strength.
15 In addition, such concave and convex portions may be formed between the lower
housing 200 and the lower end plate 300 and/or between the lower cover 400 and
the lower end plate 300. For example, protrusions may protrude downward from
the lower surface of the lower end plate 300, and downwardly-recessed concave
portions may be formed in an upper surface of the lower cover 400 such that the
20 protrusions may be inserted into the concave portions. In addition, protrusions
may protrude upward from the upper surface of the lower end plate 300, and
upwardly-recessed concave portions corresponding to the protrusions may be
formed in the lower surface of the lower housing 200.
In this case, the lower end plate 300 may be easily assembled together with the
25 lower housing 200 or the lower cover 400.
In addition, preferably, the lower end plate 300 may include at least one bolt 310
protruding upward.
For example, referring to FIG. 2, the lower end plate 300 may include a plurality of
long bolts 310 extending upward, and lower ends of the long bolts 310 may be
19
fixedly coupled to a plate-shaped main body of the lower end plate 300. For
example, the lower ends of the long bolts 310 may be fixedly coupled to the main
body of the lower end plate 300 using nuts.
In this configuration, the lower housing 200 may include at least one through-hole to
5 receive the at least one bolt 310.
For example, referring to FIG. 2, the lower housing 200 may includes a plurality of
through-holes H2 in positions and shapes corresponding to the long bolts 310.
Therefore, when the lower end plate 300 is placed on the lower portion of the lower
housing 200, the long bolts 310 of the lower end plate 300 may be placed in the
10 inner space of the lower housing 200 through the through-holes H2.
In addition, the bolts 310 of the lower end plate 300 placed in the inner space of the
lower housing 200 may penetrate portions of the cell assembly 100 as shown in FIG.
1. That is, as indicated by H1 in FIG. 2, one or more insertion holes may be
vertically formed through the cell assembly 100, and the bolts 310 of the lower end
15 plate 300 may be inserted into the insertion holes H1 of the cell assembly 100.
In this case, the insertion holes H1 of the cell assembly 100 may be formed in each
of the cartridges 120. For example, when the cell assembly 100 includes a
plurality of cartridges 120 accommodating secondary cells 110 and stacked in a
vertical direction, the insertion holes H1 may be vertically formed through outer
20 circumferential portions of the cartridges 120 as shown in FIG. 3. In addition,
when the cartridges 120 are stacked, the insertion holes H1 may be connected to
each other, and the bolts 310 of the lower end plate 300 may be inserted into the
connected insertion holes H1.
Thus, according to this configuration of the present disclosure, relative movement of
25 the cartridges 120 is prevented in the inner space of the lower housing 200, and thus
relative movement of the secondary cells 110 accommodated in the inner spaces of
the cartridges 120 may also be prevented. In addition, when the plurality of
cartridges 120 are stacked in the inner space of the lower housing 200, since the
bolts 310 of the lower end plate 300 are inserted into the insertion holes H1 of the
20
cartridges 120, the stacking of the cartridges 120 may be guided.
In addition, according to this configuration of the present disclosure, the lower end
plate 300 including the bolts 310 is placed at and fixed to the lower portion of the
lower housing 200, and the bolts 310 are placed in the inner space of the lower
housing 200 through the through-5 holes H2. Thus, the positions of the bolts 310
may not be varied while the battery pack is used. Therefore, even when the battery
pack is impacted or vibrated, the positions of the bolts 310 may not be varied, and
thus the cell assembly 100 may not be relatively moved.
In addition, according to this configuration of the present disclosure, a process of
10 forming the cell assembly 100 and a process of accommodating the cell assembly
100 in the lower housing 200 may be performed at the same time, instead of
stacking the plurality of cartridges 120 and the plurality of secondary cells 110 to
form the cell assembly 100 and then fixedly accommodating the cell assembly 100
in the lower housing 200. Therefore, according to this aspect of the present
15 disclosure, the battery pack may be manufactured in a short time with high
processability.
In particular, in the battery pack of the present disclosure, the cell assembly 100 may
be constructed by vertically stacking the secondary cells 110 and the cartridges 120,
and the lowermost cartridge 120 of the cell assembly 100 may be placed on a
20 bottom surface of the lower housing 200 in the inner space of the lower housing 200.
That is, in the battery pack of the present disclosure, the lower end plate 300
complementing the rigidity of the cell assembly 100 is provided in the pack case.
Therefore, it is not necessary to place an additional metallic end plate on a lower
portion of the cell assembly 100. Therefore, in the battery pack of the present
25 disclosure, not an end plate but a cartridge 120 may be located on the lower portion
of the cell assembly 100, and the cartridge 120 may be placed on the lower surface
of the lower housing 200 in the inner space of the lower housing 200.
Therefore, according to this aspect of the present disclosure, since the lower housing
200, which may include a plastic material, is placed between the cell assembly 100
21
and the lower end plate 300, electrical insulation between the cell assembly 100 and
the lower end plate 300 may be ensured. In addition, the lower end plate 300 may
complement the rigidity of the pack case and the rigidity of the cell assembly 100 as
well.
FIG. 7 is an exploded perspective view schematically 5 illustrating a configuration of
a battery pack according to an embodiment of the present disclosure, and FIG. 8 is
an assembled perspective view illustrating the battery pack shown in FIG. 7.
Referring to FIG. 7, the battery pack of the embodiment of the present disclosure
may further include an upper end plate 600.
10 The upper end plate 600 may include a plate-shaped metallic material and may be
provided on an upper portion of a cell assembly 100. The upper end plate 600 may
cover the upper portion of the cell assembly 100 to fix the cell assembly 100 in the
upper portion of the cell assembly 100, complement the rigidity of the cell assembly
100, and maintain surface pressure acting on the upper portion of the cell assembly
15 100. In addition, the upper end plate 600 may protect the cell assembly 100 from
external impacts.
Furthermore, bolts 310 of a lower end plate 300 may penetrate the upper end plate
600. That is, the bolts 310 of the lower end plate 300 may be inserted through
coupling holes H1 of cartridges 120 and the upper end plate 600 as well.
20 In this case, the upper end plate 600 may be fixed using the bolts 310 of the lower
end plate 300. Therefore, according to this configuration of the present disclosure,
fastening parts or spaces for fixing the upper end plate 600 to the lower housing 200
or the cell assembly 100 may be reduced in number or may not be used. Therefore,
manufacturing processes may be simplified, manufacturing costs and times may be
25 reduced, and the inner space of the battery pack may be more efficiently used.
In addition, preferably, the battery pack of the embodiment of the present disclosure
may further include an electric-component plate 700 as shown in FIG. 7.
22
The electric-component plate 700 has a plate shape, and at least one electric
component such as a BMS, a current sensor, a relay, and a fuse may be mounted on
the electric-component plate 700. The electric-component plate 700 may be
electrically connected to secondary cells 110 of the cell assembly 100.
Here, the BMS refers to a battery management 5 system configured to control
charging and discharging operation steps of the battery pack. In general, such a
BMS is included in a battery pack. The current sensor is a component configured
to sense charge and discharge currents of the battery pack. The relay is a switching
device configured to selectively open and close a charge/discharge path through
10 which charge and discharge currents of the battery pack flow. In addition, the fuse
is provided along the charge/discharge path of the battery pack, and if an abnormal
situation occurs, the fuse melts and blocks charge/discharge current of the battery
pack. The current sensor, the relay, and the fuse may exchange information with
the BMS, and may be controlled by the BMS.
15 The electric-component plate 700 may be provided above the cell assembly 100.
In addition, in an embodiment in which the upper end plate 600 is provided above
the cell assembly 100, the electric-component plate 700 may be placed above the
upper end plate 600. According to this configuration of the present disclosure,
electric components may be easily mounted, assembled, and replaced.
20 In addition, the bolts 310 of the lower end plate 300 may penetrate the electriccomponent
plate 700. That is, the bolts 310 of the lower end plate 300 may
penetrate the coupling holes H1 of the cartridges 120, the upper end plate 600, and
the electric-component plate 700 as well.
According to this configuration of the present disclosure, fastening parts or spaces
25 for fixing the electric-component plate 700 inside a pack case may be decreased in
number or may not be used. Therefore, in this case, manufacturing processes may
be simplified, manufacturing costs and times may be reduced, and the inner space of
the battery pack may be more efficiently used.
In addition, the battery pack of the present disclosure may further include a duct D
23
for allowing a coolant such as air to flow into and out of the cell assembly 100. In
particular, the duct D may include an inlet duct for introducing the coolant into the
cell assembly 100, and an outlet duct for discharging the coolant from the cell
assembly 100. The inlet duct and the outlet duct may be located at opposite sides
5 for smooth flow of the coolant.
Furthermore, the coolant introduced through the inlet duct may flow between the
secondary cells 110. In particular, each of the cartridges 120 may include two
cooling plates 122 spaced a predetermined distance from each other, and the coolant
may be introduced through gaps between the cooling plates 122. The coolant
10 flowing through the gaps between the cooling plates 122 of the cartridges 120 may
be discharged to the outside through the outlet duct.
In addition, preferably, as shown in FIGS. 7 and 8, the battery pack of the present
disclosure may further include an upper housing 500.
The upper housing 500 may be coupled to an opened upper side of the lower
15 housing 200 to seal the opened upper side. The upper housing 500 may include a
plastic material to guarantee electrical insulation, lightness, and formability.
In particular, the upper housing 500 may be fastened and fixed to the lower housing
200 using the bolts 310 of the lower end plate 300. That is, the upper housing 500
may include coupling holes H5 at positions corresponding to the bolts 310 of the
20 lower end plate 300, and the bolts 310 of the lower end plate 300 may be inserted
through the coupling holes H5 and protrude from an upper portion of the upper
housing 500. In addition, fastening members such as nuts may be coupled to
protruding upper ends of the bolts 310, so as to fasten and fix the upper housing 500
to the bolts 310. The bolts 310 are mounted on the lower end plate 300 which is
25 fixed to a lower portion of the lower housing 200, and thus the upper housing 500
fastened and fixed to the bolts 310 may be regarded as being fastened and fixed to
the lower housing 200.
According to this configuration of the present disclosure, since the lower housing
200 and the upper housing 500 are fixedly coupled to each other using the bolts 310
24
of the lower end plate 300, additional fastening members are not required to fasten
the lower housing 200 and the upper housing 500 to each other. Therefore,
according to this aspect of the present disclosure, the processability and productivity
of the battery pack may be improved, and the structure of the battery pack may be
simplified. Furthermore, according to 5 the present disclosure, the lower end plate
300 is placed below the lower housing 200, and the upper housing 500 is coupled to
the bolts 310 of the lower end plate 300. Thus, the coupling strength between the
lower housing 200 and the upper housing 500 may be high.
In addition, a sealing member may be included between the upper housing 500 and
10 the lower housing 200. For example, a sealing member formed of rubber or
silicone may be provided in a ring shape along contact edge portions of the upper
housing 500 and the lower housing 200. According to this configuration of the
present disclosure, sealing between the upper housing 500 and the lower housing
200 may be improved owing to the sealing member, thereby preventing permeation
15 of moisture or foreign substances such as dust between the upper housing 500 and
the lower housing 200. In addition, according to this configuration of the present
disclosure, even when gas is generated from the secondary cells 110, it is possible to
discharge the gas along an intended path, thereby preventing the gas from leaking
through an unexpected path and users from breathing in the gas.
20 The battery pack of the present disclosure may further include other elements in
addition to the above-described elements. For example, the battery pack of the
present disclosure may further include a bus bar for transmitting charge or discharge
power to or from the cell assembly 100, a cable for transmitting electric signals, and
a power terminal for connection to an external charge/discharge device.
25 The battery pack of the present disclosure may be applied to automobiles such as
electric or hybrid vehicles. That is, according to the present disclosure, an
automobile may include the battery pack according to the present disclosure. In
particular, a vehicle such as an electric vehicle obtaining driving power from a
battery may include a middle to large-sized battery pack, and in this case, factors
30 such as ensuring the rigidity and coupling strength of the battery pack, improving
25
the energy density of the battery pack, and reducing the weight and size of the
battery pack may be important. Therefore, when the battery pack of the present
disclosure is applied to such a vehicle, these factors may be improved.
FIG. 9 is a flowchart schematically illustrating a method of manufacturing a battery
5 pack according to an embodiment of the present disclosure.
Referring to FIG. 9, according to the embodiment of the present disclosure, the
method of manufacturing a battery pack includes: placing a lower end plate 300 on a
lower portion of a lower housing 200 (S110); placing a lower cover 400 on a lower
portion of the lower end plate 300 (S120); fixedly coupling the lower cover 400 and
10 the lower housing 200 to each other (S130); and stacking secondary cells 110 and
cartridges 120 in an inner space of the lower housing 200 (S140).
In operation step S110, the lower end plate 300, which is formed of a plate-shaped
metallic material, may be brought into surface contact with the lower portion of the
lower housing 200 having an empty inner space and an opened upper side.
15 In operation step S120, the lower cover 400 may be placed on the lower portion of
the lower end plate 300 to cover the lower end plate 300. In operation step S130,
at least a side of the lower cover 400 and at least a side of the lower housing 200
may be fixedly coupled to each other.
In operation step S140, the secondary cells 110 and the cartridges 120
20 accommodating the secondary cells 110 while surrounding outer circumferential
portions of the secondary cells 110 from the outsides of the secondary cells 110 may
be stacked in the inner space of the lower housing 200.
In operation step S130, preferably, a laser welding method may be used.
In addition, preferably, the lower end plate 300 may include at least one bolt 310
25 protruding upward, and the lower housing 200 may include at least one through-hole
H2. Therefore, in operation step S110, the bolt 310 of the lower end plate 300 may
be inserted through the through-hole H2 of the lower housing 200.
26
In addition, preferably, each of the cartridges 120 may include at least one insertion
holes H1. Thus, in operation step S140, the bolt 310 of the lower end plate 300
may be inserted through the insertion holes H1 of the cartridges 120.
Furthermore, after operation step S140, the method may further include an operation
step of placing an upper end plate 600, which 5 is formed of a plate-shaped metallic
material, on an upper portion of the cell assembly 100. In this case, the bolt 310 of
the lower end plate 300 may be inserted through the upper end plate 600.
In addition, after operation step S140, the method may further include an operation
step of placing an electric-component plate 700, on which at least one of a BMS, a
10 current sensor, a relay, and a fuse is mounted, on the upper portion of the cell
assembly 100. In this case, the bolt 310 of the lower end plate 300 may be inserted
through the electric-component plate 700. In addition, if the battery pack includes
the upper end plate 600, the electric-component plate 700 may be placed on an
upper end of the upper end plate 600.
15 In addition, after the operation step S140, the method may further include an
operation step of coupling an upper housing 500 to the opened upper side of the
lower housing 200 in a state in which the bolt 310 of the lower end plate 300 is
inserted through the upper housing 500 and an operation step of coupling a fastening
member such as a nut to the bolt 310 of the lower end plate 300 protruding upward
20 from the upper housing 500.
While embodiments of the present disclosure has been described with reference to
the accompanying drawings, it should be understood that the embodiments are given
by way of illustration only, and various changes and modifications within the scope
of the disclosure as defined by the appended claims will become apparent to those
25 skilled in the art.
In the present disclosure, terms indicating directions such as upward and downward
are used to express relative positions. These terms are for ease of description, and
it will be apparent to those skilled in the art that these terms may vary depending on
the position of an object or an observer.
27
WE CLAIM: -
1. A battery pack comprising:
a cell assembly comprising a plurality of secondary cells and a plurality of
cartridges, the cartridges being configured 5 to be stacked on one another and to
accommodate the secondary cells while surrounding outer circumferential
portions of the secondary cells from outsides of the secondary cells;
a lower housing having an empty inner space to accommodate the cell assembly
in the inner space, the lower housing being opened on an upper side thereof;
10 a lower end plate comprising a plate-shaped metallic material and placed in
surface contact with a lower surface of the lower housing; and
a lower cover placed on a lower portion of the lower end plate to cover the
lower end plate, the lower cover being fixedly coupled to the lower housing.
2. The battery pack of claim 1, wherein the lower cover is fixedly coupled to the
15 lower housing by a laser welding method.
3. The battery pack of claim 2, wherein the lower cover and the lower housing
comprise the same plastic material.
4. The battery pack of claim 1, wherein the lower cover is fixedly coupled to the
lower housing along and outside an edge of the lower end plate.
20 5. The battery pack of claim 1, wherein at least one opening is formed in a center
portion of the lower end plate, and
the lower cover is fixedly coupled to the lower housing through the opening.
6. The battery pack of claim 1, wherein the lower housing and the lower cover
comprise concave and convex portions corresponding to each other.
25 7. The battery pack of claim 1, wherein the lower end plate comprises at least one
bolt protruding upward, and
at least one through-hole is formed in the lower housing to pass the bolt through
the through-hole.
28
8. The battery pack of claim 7, wherein at least one insertion hole is formed in the
cell assembly, and
the bolt is inserted in the insertion hole.
9. The battery pack of claim 1, wherein the secondary cells and the cartridges of
the c 5 ell assembly are vertically stacked, and
a lowermost cartridge of the cell assembly is placed in the inner space of the
lower housing in contact with a bottom surface of the lower housing.
10. The battery pack of claim 1, further comprising an upper end plate comprising a
plate-shaped metallic material and provided on an upper portion of the cell
10 assembly to cover the upper portion of the cell assembly.
11. The battery pack of claim 1, further comprising an upper housing coupled to the
opened upper side of the lower housing to seal the opened upper side.
12. An automobile comprising the battery pack of any one of claims 1 to 11.
13. A method of manufacturing a battery pack, the method comprising:
15 placing a lower end plate comprising a plate-shaped metallic material on a
lower portion of a lower housing comprising an empty inner space and an
opened upper side such that the lower end plate makes surface contact with the
lower portion of the lower housing;
placing a lower cover on a lower portion of the lower end plate to cover the
20 lower end plate;
fixedly coupling the lower cover and the lower housing to each other; and
stacking secondary cells and cartridges in the inner space of the lower housing,
the cartridges accommodating the secondary cells while surrounding outer
circumferential portions of the secondary cells from outsides of the secondary
25 cells.
14. The method of claim 13, wherein, in the fixedly coupling of the lower cover and
the lower housing to each other, the lower cover and the lower housing are
fixedly coupled to each other by a laser welding method.
29
15. The method of claim 13, wherein the lower end plate comprises at least one bolt
protruding upward, and the lower housing comprises at least one through-hole,
and
in the placing of the lower end plate, the bolt of the lower end plate is passed
5 through the through-hole of the lower housing.
16. The method of claim 15, wherein at least one insertion hole is formed in each of
the cartridges, and in the stacking of the secondary cells and the cartridges, the
bolt of the lower end plate is inserted into the insertion holes of the cartridges.