Battery module and method for manufacturing the battery module

Abstract

To cause a restraining member and an end plate to realize restraining and holding different from mechanical fastening in a battery module and a manufacturing method of the battery module in which rectangular battery cells are laminated in the thickness direction and restrained.SOLUTION: A battery module includes a plurality of prismatic battery cells 12 stacked in the thickness direction, a cooling device 20 (restraining member) made of a metal plate that restrains the battery cells 12 from both sides intersecting the stacking direction, and end plates 30 made of metal plates that sandwich the battery cell 12 from both ends in the stacking direction of the battery cell 12, and further includes a joint 40 joined by laser welding in a state in which the cooling device 20 (restraining member) and the end plate 30 are superimposed in the plate thickness direction, and the plurality of battery cells 12 are restrained and held by the cooling device 20 (restraining member) and the end plate 30 which are joined by the joint 40.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present invention relates to a battery module and a method for manufacturing a battery module. [Background technology]

[0002] Conventionally, a battery module such as that described in Patent Document 1 has been known. The battery module in Patent Document 1 has a plurality of rectangular battery cells stacked in the thickness direction, metal plate restraining members that restrain the battery cells from both sides intersecting the stacking direction, and metal plate end plates that sandwich the battery cells from both ends in the stacking direction. In order to restrain and maintain the stacked state of the battery cells, a structure has been used in which the restraining members and the end plates are fixed by mechanical fastening means such as bolts, nuts, rivets, etc. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2005-339929 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, the mechanical fastening means described above has concerns that the structure is bulky, making the battery module larger, and that the weight of the fastening members increases the weight of the entire battery module. In addition, there are concerns about slippage and loosening associated with the mechanical fastening means, and further improvements are desired.

[0005] The present invention was devised in light of these circumstances, and the problem that the present invention aims to solve is to provide a battery module and a manufacturing method for a battery module in which rectangular battery cells are stacked in the thickness direction and held in a restraining manner that differs from mechanical fastening, in which restraining members and end plates are used. [Means for solving the problem]

[0006] In order to solve the above problems, the battery module of the present invention takes the following measures: First, a first invention has a plurality of rectangular battery cells stacked in the thickness direction, metal plate restraining members that restrain the battery cells from both sides that intersect with the stacking direction, and metal plate end plates that sandwich the battery cells from both ends in the stacking direction, with joints where the restraining members and the end plates are joined by laser welding while overlapping in the plate thickness direction, and the plurality of battery cells are restrained and held by the restraining members and the end plates joined by the joints.

[0007] Next, a second invention is a battery module according to the first invention, wherein the restraint member is made of multiple metal plates stacked at the portion where it overlaps with the end plate, and the joint is configured such that the restraint member of the multiple metal plates and the end plate are melted in the plate thickness direction to be integrated.

[0008] Next, a third invention is a battery module according to the first or second invention, wherein the joint has a linear first weld extending in a direction intersecting the stacking direction of the battery cells, and a linear second weld extending in the stacking direction of the battery cells.

[0009] Next, a fourth invention is the battery module according to the third invention, wherein the joint portion is configured by the first welded portion and the second welded portion being linearly connected to each other.

[0010] Next, a fifth invention is a battery module according to any one of the first to fourth inventions, wherein the restraint member is formed by welding the peripheral edges of two metal plates together to form a sealed space, and a refrigerant-filled chamber filled with refrigerant is defined within the sealed space, and the battery module is arranged vertically to provide a function of cooling the battery cells from the sides.

[0011] Next, a manufacturing method of a battery module of the present invention takes the following steps. A sixth invention includes a step of stacking a required number of rectangular battery cells having multiple rectangular battery cells stacked in the thickness direction, metal plate restraining members that restrain the battery cells from both sides intersecting the stacking direction, and metal plate end plates that sandwich the battery cells from both ends of the battery cell stacking direction, a step of compressing the battery cells while the end plates are in surface contact with both ends of the battery cell stacking direction, a step of setting the restraining members from both sides in a state compressed in the stacking direction of the battery cells, and a step of laser welding the restraining members and the end plates overlapping in the plate thickness direction with the end plates at both ends of the battery cells and the restraining members on both sides set to form joints, and the multiple battery cells are restrained and held by the restraining members and the end plates joined by the joints.

[0012] Next, a seventh invention is a manufacturing method for a battery module related to the sixth invention, wherein the restraint member is made of multiple metal plates stacked at a portion where it is overlapped with the end plate, and the joint is configured such that the restraint member of the multiple metal plates and the end plate are melted in the plate thickness direction to be integrated.

[0013] Next, an eighth invention is a manufacturing method for a battery module according to the sixth or seventh invention, wherein the joint has a linear first weld extending in a direction intersecting the stacking direction of the battery cells, and a linear second weld extending in the stacking direction of the battery cells.

[0014] A ninth aspect of the present invention is a method for manufacturing a battery module according to the eighth aspect of the present invention, wherein the joint portion is formed by linearly connecting the first welded portion and the second welded portion.

[0015] Next, a tenth invention is a manufacturing method for a battery module according to any one of the sixth to ninth inventions, wherein the restraint member is formed by welding the peripheral portions of two metal plates together with their faces together to form a sealed space, and a refrigerant-filled chamber is formed within the sealed space in which a refrigerant is filled, and the restraint member is arranged vertically to provide a function of cooling the battery cells from the sides. Effect of the Invention

[0016] By adopting the means described above, the present invention can provide a battery module and a manufacturing method for a battery module in which rectangular battery cells are stacked in the thickness direction and held in a restraining manner that differs from mechanical fastening by the restraining members and end plates. [Brief description of the drawings]

[0017] [Figure 1] FIG. 1 is an overall perspective view showing an embodiment of the present invention. [Diagram 2] FIG. 2 is a perspective view showing a restraining member and an end plate according to the present embodiment. [Diagram 3] 4 is a cross-sectional view of the restraining member of the present embodiment. FIG. [Figure 4] 5 is a schematic diagram showing a joint between a restraining member and an end plate in the present embodiment. FIG. [Diagram 5] 5 is a schematic diagram showing a joint between a restraining member and an end plate in the present embodiment. FIG. [Figure 6] 10 is a schematic diagram showing a first modified example of a joint between a restraining member and an end plate in the present embodiment. FIG. [Figure 7] 10 is a schematic diagram showing a modified example 2 of the joint between the restraining member and the end plate in the present embodiment. FIG. [Figure 8] 13 is a schematic diagram showing a third modified example of a joint between a restraining member and an end plate in the present embodiment. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0018] Hereinafter, an embodiment for carrying out the present invention will be described with reference to Figs. 1 to 5.

[0019] For example, vehicles (not shown) include electric automobiles, gasoline hybrid vehicles, and fuel cell hybrid vehicles that run using an electric motor (not shown) as a drive source. Such vehicles are equipped with a battery pack (not shown) as a battery that stores power supplied to the electric motor under a floor panel (not shown) that constitutes the vehicle floor. The battery pack incorporates a plurality of battery modules 10 and a battery ECU (not shown), and is formed into a flat box shape as a unit that can be mounted on a vehicle as a battery system. Here, the battery module 10 has both functions of discharging and charging electric energy for driving a motor, and is composed of a plurality of rectangular single cells called battery cells 12 connected together. The battery cells 12 are storage batteries that use lithium ion batteries, nickel metal hydride batteries, or the like. The battery ECU is an electronic control unit of the battery pack.

[0020] This embodiment will be described by taking as an example a battery module 10 used in an electric vehicle. Here, the directions of the battery module 10 will be described as the X direction (or X1, X2 side), the Y direction (or Y1, Y2 side), and the Z direction (or Z1, Z2 side), as indicated by the X, Y, and Z arrows in the figure. Here, the Z direction is the direction of gravity. These directions are the same in each figure.

[0021] <Overall composition> As shown in Figs. 1 to 3, the battery module 10 is formed by connecting a plurality of rectangular battery cells 12 in series. The battery cells 12 are stacked in the thickness direction (stacking direction) and combined in the required number. The battery module 10 is integrated by being held and restrained on all four sides by a cooling device 20 as a restraining member and an end plate 30. The cooling device 20 has a function as a restraining member that restrains the positions of the plurality of battery cells 12 on both sides (X direction), and also has a function of restraining the plurality of battery cells 12 in the stacking direction (Y direction) in cooperation with the end plate 30 by fixing the end plate 30 described later. The cooling device 20 has a function of cooling each battery cell 12 from both sides. The end plate 30 has a function of sandwiching and restraining the battery cells 12 from both ends in the stacking direction (Y direction) of the plurality of battery cells 12 in cooperation with the cooling device 20 as the above-mentioned restraining member. Here, the restraining member is also called a "restraint band" or "tension plate".

[0022] <Cooling device 20 (restraint member)> 1 to 3, the cooling device 20 (restraint member) is a metal plate member that restrains the battery cells 12 from both sides (X direction) that intersect with the stacking direction. The cooling device 20 is composed of two steel plates 20a, 20b whose peripheral edges are welded together with their faces joined to form a sealed space, and the sealed space is filled with hydrofluorocarbon (HFC) as a refrigerant to form a refrigerant-filled chamber 21. The cooling device 20 is arranged vertically to have the function of cooling the battery cells 12 from the sides. In other words, the steel plates 20a, 20b also function as heat transfer plates in the refrigerant-filled chamber 21.

[0023] 1 and 3, one side in the Y direction of the refrigerant filling chamber 21 is provided with a refrigerant outlet path 22 through which the refrigerant vaporized by heat from the battery cells 12 flows out. The refrigerant outlet path 22 and the condenser 3 are connected via a flow path 4. The other side in the Y direction of the refrigerant filling chamber 21 is provided with a refrigerant inlet path 24 through which the refrigerant that has been condensed and cooled in the condenser 3 and is circulated flows into the refrigerant filling chamber 21. The condenser 3 and the refrigerant inlet path 24 are connected via a flow path 5.

[0024] With this configuration, in the refrigerant charging chamber 21, the refrigerant vaporized by the heat of each battery cell 12 flows out of the refrigerant outlet passage 22 and is sent to the condenser 3 through the passage 4 as shown by the arrow in FIG. 1. The refrigerant that is condensed, cooled, and re-liquefied in the condenser 3 is circulated from the refrigerant inlet passage 24 to the refrigerant charging chamber 21 through passage 5 as shown by the arrow in FIG. 1. This action is repeated to cool each battery cell 12 by the refrigerant charging chamber 21. The refrigerant liquefied in the refrigerant charging chamber 21 is maintained at a constant liquid level. Thus, the refrigerant charging chamber 21 functions as a refrigerant passage through which the refrigerant flows in the sealed space between the steel plates 20a, 20b. As described above, the cooling device 20 is a boiling cooling type device in which the refrigerant charging chamber 21, filled with the refrigerant that vaporizes by the heat of the battery cells 12, is disposed to the side of the battery cells 12, and cooling is performed by boiling heat transfer via the steel plates 20a, 20b in the refrigerant charging chamber 21.

[0025] <End plate 30> The end plate 30 is a member made of a metal plate and has clamping surfaces 32 that clamp the battery cells 12 from both ends in the stacking direction (Y direction) of the battery cells 12, and joint surfaces 34 that are bent at both ends of the clamping surfaces 32 to face the steel plate 20a of the cooling device 20. Here, the steel plates 20a, 20b of the cooling device 20 and the joint surfaces 34 of the end plates 30 are superimposed on each other.

[0026] <Joining of Cooling Device 20 and End Plate 30> Next, the structure of the joint between the cooling device 20 and the end plate 30 will be described. As shown in Fig. 4, the steel plates 20a, 20b of the cooling device 20 and the joint surface 34 of the end plate 30 have a joint 40 that is joined by laser welding while overlapping in the plate thickness direction. The joint 40 is configured such that the steel plates 20a, 20b of the cooling device 20 and the joint surface 34 of the end plate 30 are melted in the plate thickness direction to be integrated. Here, as shown in Fig. 5, the joint 40 has a linear first welded portion 41 that extends in a direction (Z direction) that intersects with the stacking direction of the battery cells 12. The joint 40 also has a linear second welded portion 42 that extends in the stacking direction of the battery cells 12 (Y direction). The first welded portion 41 and the second welded portion 42 are linearly connected to each other to form a substantially U-shape.

[0027] <Manufacturing Method (Assembly) of Battery Module 10> The manufacturing method (assembly method) of the battery module 10 will be described. First, a required number of rectangular battery cells 12 are stacked together (stacking process). Next, the battery cells 12 are compressed in a state where the clamping surfaces 32 of the end plates 30 are in surface contact with both ends of the stacking direction (Y direction) of the battery cells 12 (compression process). Next, while the battery cells 12 are compressed in the stacking direction (Y direction), the cooling devices 20 (restraint members) are set (applied, arranged, installed) from both sides (X direction) (setting process). Next, with the end plates 30 at both ends (Y direction) of the battery cells 12 and the cooling devices 20 at both sides (X direction) set, the steel plates 20a, 20b of the cooling devices 20 and the joint surfaces 34 of the end plates 30 are stacked in the plate thickness direction, and laser welding is performed to provide the above-mentioned joints 40 (joining process). The cooling device 20 (restraint member) and the end plates 30 joined by the joints 40 restrain and hold the multiple battery cells 12 on all four sides to form an integrated battery module 10.

[0028] <Modification> In the above, the joint 40 is configured to be substantially U-shaped, but the present invention is not limited thereto, and may be configured as shown in, for example, Figs. 6 to 8. For example, Fig. 6 shows a schematic diagram of a joint 140 between the cooling device 20 (restraint member) and the end plate 30 as a first modified example of the present embodiment. For example, the first welded portion 141 and the second welded portion 142 may be separated. The number of the second welded portions 142 is not limited to two, and may be three or more. Although not shown, the first welded portion 141 may also be configured to have a plurality of portions. For example, Fig. 7 shows a schematic diagram of a joint 240 between the cooling device 20 (restraint member) and the end plate 30 as a second modified example of the present embodiment. For example, the first welded portion 241 and the second welded portion 242 may be joined to have a substantially E-shaped configuration. For example, Fig. 8 shows a schematic diagram of a joint 340 between the cooling device 20 (restraint member) and the end plate 30 as a third modified example of the present embodiment. For example, the joint 340 may have a wavy or substantially W-shaped configuration in which the first welded portion 341 and the second welded portion 342 are linearly connected.

[0029] <Actions and Effects> The battery module 10 of this embodiment has a structure in which the cooling device 20 (restraint member) and the end plate 30 are joined by welding to overlap and restrain the battery cells 12. Here, the cooling device 20 (restraint member) and the end plate 30 are pressed steel plate products, and laser welding is used for welding them together. The reason for using laser welding is that the welding penetration force into the steel plate is high, the thermal impact on surrounding parts due to localized heat generation is small, and there is little deterioration in accuracy due to thermal distortion. In contrast, when arc welding is used, the welding heat input is large, and there is a concern that the accuracy will deteriorate due to thermal distortion. Furthermore, since the welding penetration force into the steel plate is low with arc welding, the steel plate (steel plate 20a in this embodiment) on the cooling device 20 (restraint member) side and the joint surface 34 are welded one by one, which is considered to reduce the strength. Furthermore, when spot welding is used, there is a concern that the product will become larger because the required flat surface for welding is large. Furthermore, with spot welding, there is a concern that the strength will decrease because the welding point pitch (welding point dimension) is wide. Furthermore, the battery cells 12 need to be restrained and held so that they do not come apart due to vehicle vibration. In addition, in order to fully utilize the performance of the battery cells 12, it is considered good to increase the adhesion inside the battery by restraining and holding the battery cells 12 in a state where a compressive load is applied to the front surface (stacking direction) of the battery cells 12. Here, when assembling the battery cells 12 in a compressed state, the overall length may vary for each battery module 10 due to variations in the dimensions of the individual battery cells 12. In order to deal with this, for example, when fastening and fixing using bolts and nuts is adopted, it becomes necessary to make the fastening holes elongated in order to absorb the above-mentioned variations. Here, when fastening and fixing using bolts and nuts via elongated holes, the contact area of ​​the fastening surfaces is reduced, so that the surface pressure becomes insufficient, and there is a concern that slippage and loosening may occur. In contrast, by adopting laser welding, it is possible to suppress these concerns of slippage and loosening. For the above reasons, laser welding has been adopted.

[0030] Furthermore, when a battery cell is charged and discharged, the battery itself expands and contracts repeatedly. Particularly during expansion, a large tensile load is applied to the cooling device 20 and the end plate 30, raising concerns that the joints may be damaged. To address this, measures to strengthen the joints and their surroundings, and structural measures to reduce the stress that occurs are required. Thus, joints 40, 140, 240, and 340 are formed by laser welding the steel plates 20a and 20b of the cooling device 20 (restraint member) and the joint surface 34 of the end plate 30 together. This provides a structure in which the steel plates 20a and 20b can withstand the tensile load, thereby reducing the stress that occurs. The joints 40, 140, 240, and 340 each have a linear first weld 41, 141, 241, and 341 that extend in a direction (Z direction) intersecting the stacking direction of the battery cells 12, and a linear second weld 42, 142, 242, and 342 that extend in the stacking direction of the battery cells 12 (Y direction). This allows the generated stress to be decomposed into two components, a stress in the peeling direction and a stress in the shearing direction, and each generated stress can be efficiently reduced. Therefore, the joints 40, 140, 240, and 340 can be structured to be less susceptible to localized stress concentration. Therefore, because the joints 40, 140, 240, and 340 are configured by laser welding, there is no need to use other members to make the structure stronger, and weight and costs can be reduced.

[0031] Although the embodiment of the present invention has been described above, the battery module 10 of the present invention is not limited to this embodiment and can be embodied in various other forms. For example, in this embodiment, the cooling device 20 is exemplified as the restraining member, but the "restraining member" does not have to be a cooling device. In other words, the restraining member may be a plurality of metal plates and the joining surfaces 34 of the end plates 30 may be overlapped and laser welded.

[0032] In addition, in the present embodiment, the battery module 10 used in an electric vehicle has been described as an example of the battery, but the present invention can be applied to various battery modules 10. For example, the present embodiment may be applied to a battery for supplying home power, a battery for vehicles other than automobiles, etc. In addition, in the present embodiment, the battery cells 12 are connected in series to form one battery module 10, but the battery cells 12 may be connected in parallel, or a combination of series and parallel.

[0033] In addition, the cooling device 20 is shown to be made of steel plates 20a, 20b, but may be made of copper, aluminum, etc. Although hydrofluorocarbons (HFCs) are exemplified as refrigerants, alternative fluorocarbons such as hydrofluoroolefins (HFOs) may also be used.

[0034] <Effects of the above embodiments corresponding to each invention> Finally, the effects of the above-described embodiments corresponding to the first and subsequent inventions in the "Means for Solving the Problems" section will be described below.

[0035] According to the first aspect of the present invention, a battery module 10 includes a plurality of rectangular battery cells 12 stacked in the thickness direction, a cooling device 20 (restraint member) made of a metal plate that restrains the battery cells 12 from both sides intersecting the stacking direction, and end plates 30 made of a metal plate that sandwich the battery cells 12 from both ends in the stacking direction. The cooling device 20 (restraint member) and the end plates 30 have joints 40, 140, 240, 340 that are joined by laser welding while overlapping in the plate thickness direction. The cooling device 20 (restraint member) and the end plates 30 joined by the joints 40, 140, 240, 340 restrain and hold the plurality of battery cells 12. Therefore, due to the configuration of the joints 40, 140, 240, 340 by laser welding, it is possible to suppress an increase in weight of the fastening members, unlike a mechanical fastening configuration. In addition, slippage, loosening, and the like that accompany mechanical fastening are less likely to occur.

[0036] According to the second invention, the cooling device 20 (restraint member) is made of multiple metal plates overlapping at the portion where it is joined to the end plate 30, and the joints 40, 140, 240, 340 are configured such that the cooling device 20 (restraint member) made of multiple metal plates and the end plate 30 are melted in the plate thickness direction to be integrated together. Therefore, the cooling device 20 (restraint member) made of multiple metal plates and the end plate 30 are melted in the plate thickness direction to be integrated together. In other words, the mechanical strength is improved because multiple metal plates are welded together.

[0037] According to the third aspect of the present invention, the joints 40·140·240·340 have first linear welds 41·141·241·341 extending in a direction intersecting the stacking direction of the battery cells 12, and second linear welds 42·142·242·342 extending in the stacking direction of the battery cells 12. Therefore, by having linear welds extending in different directions, the joints 40·140·240·340 can decompose the tensile load caused by battery expansion due to charging / discharging of the battery cells into two components, a stress in the peeling direction and a stress in the shearing direction, thereby efficiently reducing the respective stresses. Therefore, the joints 40·140·240·340 can have a structure that is less susceptible to local stress concentration.

[0038] According to the fourth aspect of the present invention, the joints 40, 140, 240, and 340 are formed by linearly connecting the first welded parts 41, 141, 241, and 341 and the second welded parts 42, 142, 242, and 342. Therefore, the joints 40, 140, 240, and 340 can be formed efficiently.

[0039] According to the fifth aspect of the invention, cooling device 20 (restraint member) is configured by welding the peripheral portions of two metal plates together to form a sealed space, and refrigerant filled chamber 21 is configured in the sealed space filled with refrigerant, and is arranged vertically to provide a function of cooling the battery cells from the side. Providing a cooling function in the restraint member makes it possible to provide a more functional battery module 10.

[0040] According to the sixth aspect of the present invention, a manufacturing method of a battery module 10 includes a step of stacking a required number of rectangular battery cells 12, the battery cells 12 having a plurality of rectangular battery cells 12 stacked in the thickness direction, a cooling device 20 (restraint member) made of a metal plate that restrains the battery cells 12 from both sides intersecting the stacking direction, and end plates 30 made of a metal plate that sandwich the battery cells 12 from both ends in the stacking direction of the battery cells 12, a step of compressing the battery cells 12 while the end plates 30 are in surface contact with both ends in the stacking direction, and and with the end plates 30 at both ends of the battery cells 12 and the cooling devices 20 on both sides set, the cooling devices 20 and the end plates 30 are stacked in the plate thickness direction and laser welding is performed to provide joints 40, 140, 240, 340, so that the multiple battery cells 12 are restrained and held by the cooling devices 20 and end plates 30 joined by the joints 40, 140, 240, 340. This provides a manufacturing method for a battery module 10 in which rectangular battery cells 12 are stacked and held in the thickness direction and in which the cooling devices 20 (restraint members) and end plates 30 achieve restraint and holding in a manner different from mechanical fastening.

[0041] According to the seventh aspect of the invention, in the manufacturing method for the battery module 10, the cooling device 20 (restraint member) is made of a plurality of metal plates overlapping at a portion where it is to be joined with the end plate 30, and the joints 40, 140, 240, 340 are configured such that the cooling device 20 (restraint member) made of a plurality of metal plates and the end plate 30 are melted in the plate thickness direction to be integrated together. Therefore, the cooling device 20 (restraint member) made of a plurality of metal plates and the end plate 30 are melted in the plate thickness direction to be integrated together. In other words, the mechanical strength is improved by welding together a plurality of metal plates.

[0042] According to the eighth aspect of the invention, in the manufacturing method for the battery module 10, the joints 40, 140, 240, 340 have linear first welds 41, 141, 241, 341 extending in a direction intersecting the stacking direction of the battery cells 12, and linear second welds 42, 142, 242, 342 extending in the stacking direction of the battery cells 12. Therefore, by having linear welds in different directions, the joints 40, 140, 240, 340 can decompose the tensile load caused by the expansion of the battery due to charging / discharging of the battery cells into two components, a stress in the peeling direction and a stress in the shearing direction, and thereby efficiently reduce each generated stress. Therefore, the joints 40, 140, 240, 340 can be structured to be less susceptible to localized stress concentration.

[0043] According to the ninth aspect of the present invention, in the manufacturing method for the battery module 10, the joints 40, 140, 240, 340 are formed by linearly connecting the first welded parts 41, 141, 241, 341 and the second welded parts 42, 142, 242, 342. Therefore, the joints 40, 140, 240, 340 can be formed efficiently.

[0044] According to the tenth aspect of the invention, in a manufacturing method for a battery module 10, a cooling device 20 (restraint member) is formed by welding the peripheral portions of two metal plates together to form a sealed space, and a refrigerant-filled chamber 21 filled with a refrigerant is configured within the sealed space, and the cooling device 20 is arranged vertically to provide a function of cooling the battery cells from the side. Providing a cooling function to the restraint member makes it possible to provide a more functional battery module 10. [Explanation of symbols]

[0045] 3. Condenser 4 Flow Path 5 Flow Path 10 Battery module 12 Battery Cells 20 Cooling device (restraint member) 20a, 20b steel plate 21 Refrigerant filling room 22 Refrigerant outlet path 24 Refrigerant inflow path 30 End Plate 32 Clamping surface 34 Joint surface 40·140·240·340 Joint 41·141·241·341 First weld 42·142·242·342 Second weld

Claims

1. A plurality of rectangular battery cells stacked in a thickness direction; a metal plate restraining member that restrains the battery cells from both sides that intersect with the stacking direction; and end plates made of metal plates that sandwich the battery cells from both ends in a stacking direction of the battery cells, a joint portion where the restraint member and the end plate are joined by laser welding in a state where they are overlapped in a plate thickness direction, and the multiple battery cells are restrained and held by the restraint member and the end plate joined by the joint portion, The joint is a linear first weld portion extending in a direction intersecting the stacking direction of the battery cells; and a linear second weld portion extending in the stacking direction of the battery cells. Battery module.

2. The battery module according to claim 1 , The restraint member includes a plurality of metal plates overlapped at a portion where the restraint member overlaps the end plate, The joint is a battery module configured such that the restraint members of the plurality of metal plates and the end plates are integrated by being melted in the plate thickness direction.

3. A battery module according to claim 1 or claim 2, The joint is a battery module in which the first welded portion and the second welded portion are linearly connected.

4. A battery module according to any one of claims 1 to 3, The restraint member is a battery module in which the peripheral portions of two metal plates are welded together by flush-fitting to form a sealed space, a refrigerant-filled chamber is formed within the sealed space and is arranged vertically to provide cooling from the sides of the battery cells.

5. A plurality of rectangular battery cells stacked in a thickness direction; a metal plate restraining member that restrains the battery cells from both sides that intersect with the stacking direction; and end plates made of metal plates that sandwich the battery cells from both ends in a stacking direction of the battery cells, stacking a required number of rectangular battery cells; a step of compressing the end plates in a state of surface contact with both ends of the battery cells in a stacking direction; a step of setting the restraining members from both sides in a state in which the battery cells are compressed in a stacking direction; and a step of performing laser welding to form joints in a state in which the end plates at both ends of the battery cell and the restraining members on both sides are set and the restraining members and the end plates are overlapped in a plate thickness direction, the plurality of battery cells are restrained and held by the restraint member and the end plate joined by the joint, The joint is a linear first weld portion extending in a direction intersecting the stacking direction of the battery cells; and a linear second weld portion extending in the stacking direction of the battery cells. A method for manufacturing a battery module.

6. A method for manufacturing a battery module according to claim 5, comprising: The restraint member includes a plurality of metal plates overlapped at a portion where the restraint member overlaps the end plate, A method for manufacturing a battery module, wherein the joint is configured such that the restraint members of the plurality of metal plates and the end plates are melted in the plate thickness direction to be integrated together.

7. A method for manufacturing a battery module according to claim 5 or claim 6, comprising: The method for manufacturing a battery module, wherein the joint is formed by linearly connecting the first welded portion and the second welded portion.

8. A method for manufacturing a battery module according to any one of claims 5 to 7, comprising: The restraint member is a battery module manufactured by welding the peripheral portions of two metal plates together to form a sealed space, and a refrigerant-filled chamber is formed within the sealed space and is arranged vertically to provide cooling from the sides of the battery cells.

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