Battery pack and method of manufacturing the battery pack

Abstract

To provide a battery pack and a method of manufacturing a battery pack, capable of reducing manufacturing costs.SOLUTION: Two spacers 150 of a battery pack 1 adjacent to each other via a battery cell 100 include two sets of a seal structure 170 each including a bar part 161, a hollow part 171, and a fin part 174. The bar part 161 is provided at one spacer 150 and extends to a side of the other spacer 150. The hollow part 171 is provided at the other spacer 150, into which the bar part 161 provided at the one spacer 150 is press-fitted. The fin part 174 is provided on a lower face 173 of the hollow part 171 and has a tip 176 contacting the bottom inner wall face 203 of a case member 200. A cooling passage 300 is formed between the fin parts 174 of the two sets of the seal structure 170 at a space between a battery stack 10 and the bottom inner wall face 203 of the case member 200.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The disclosed technology relates to a battery pack having a battery stack formed by stacking battery cells and a case member that houses the battery stack, and a method for manufacturing the battery pack. [Background technology]

[0002] A battery pack is generally constructed by housing a battery stack, which is made by stacking multiple battery cells with spacers between them, in a case. Patent Document 1 describes an example of a spacer used in such a battery pack. In this document, the battery cells are stacked while being assembled into a battery holder that serves as a spacer to separate the battery cells. The battery holder has passages through which cooling air passes to cool the battery cells. In the battery pack, the passages in the battery holder fit together and connect to form cooling passages that pass cooling air in the stacking direction of the battery cells. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2008-103248 Summary of the Invention [Problem to be solved by the invention]

[0004] It is desirable for the battery pack to have as simple a structure as possible, as this reduces the manufacturing cost of the battery pack. However, the above-mentioned conventional technology has the problem that the battery holder has to have passages for passing cooling air, which makes the shape of the battery holder complex.

[0005] The present disclosure has been made to solve the problems of the conventional technology described above. That is, the object of the disclosure is to provide a battery pack and a method for manufacturing the battery pack that can reduce manufacturing costs. [Means for solving the problem]

[0006] One aspect of the disclosed technology is a battery pack having a battery stack formed by stacking multiple battery cells with spacers interposed between them, and a case that houses the battery stack from one end side in the stacking direction of the battery cells, and a cooling passage provided between the inner wall surface of the case and the battery stack for passing a fluid that cools the battery cells in the stacking direction, and the spacer has two sets of sealing structures for two adjacent spacers separated by a battery cell, each of which has a bar portion provided on one side and extending in the stacking direction toward the other side, a deformed portion provided on the other side and deformed due to the bar portion on the one side being pressed against it, and a fin portion provided on the deformed portion and whose tip is in contact with the inner wall surface of the case, and the cooling passage is formed between the fin portions of the two sets of sealing structures between the inner wall surface of the case and the battery stack.

[0007] In the battery pack of the above aspect, a cooling passage is provided between the two sets of fins of the sealing structure between the inner wall surface of the case and the battery stack, which allows the spacer structure to be simplified, thereby reducing the manufacturing cost of the battery pack.

[0008] In the battery pack of the above aspect, it is further preferable that the case has a groove extending in the stacking direction at the location of the cooling passage on the inner wall surface, the spacer has a fixing portion that fixes adjacent battery cells in the width direction of the groove, and the tips of the fin portions of the two sets of sealing structures are respectively in contact with different of two opposing side surfaces of the groove. In this way, the fin portions of the two sets of sealing structures receive a reaction force from the opposing different side surfaces of the groove. This reaction force allows the spacer and the battery cells fixed to the spacer to be properly aligned in the stacking direction. In other words, the configuration for forming the cooling passage can even align the battery cells in the battery stack. Therefore, there is no need to provide a special configuration for aligning the battery cells. This reduces the manufacturing cost of the battery pack.

[0009] In the battery pack of the above aspect, it is further preferable that the deformation portion deforms so as to swing the fin portion by pressing the bar portion against the fin portion, compared to when the bar portion is not pressed against the fin portion. In this way, the fin portion that moves to swing can be deformed so as to bend overall and contact the inner wall surface of the case. This makes it possible to properly form a cooling passage while preventing damage to the sealing structure and the case.

[0010] In the battery pack of the above aspect, it is further preferable that the deforming portion has a space formed therein extending in the stacking direction, and is deformed by the bar portion being press-fitted into the space. In this way, the deforming portion can be easily deformed by the bar portion being press-fitted, while being less likely to deform due to vibration or the like before the bar portion is press-fitted.

[0011] In the battery pack of the above aspect, the case preferably further includes a floor portion located below the battery stack, an end panel attached to one end in the stacking direction, and an end wall portion located on the other end opposite the end panel attachment location and integral with the floor portion, and the battery stack is held in the case while being sandwiched between the end panel and the end wall portion. In this manner, the battery stack and the end panel can be fixed by the compressive reaction force of the battery stack. In other words, for example, fastening or joining to fix the end panel is not required. This reduces the manufacturing cost of the battery pack.

[0012] Another aspect of the disclosed technology is a manufacturing method for a battery pack having a battery stack formed by stacking a plurality of battery cells with spacers interposed therebetween, and a case that houses the battery stack from one end side in the stacking direction of the battery cells, and a cooling passage that allows a fluid that cools the battery cells to pass in the stacking direction between the inner wall surface of the case and the battery stack, and the spacers include, for two adjacent spacers separated by a battery cell, a bar portion that is provided on one side and extends in the stacking direction toward the other side, a deformation portion that is provided on the other side and deforms when the bar portion on the one side is pressed against it, and a tip of the bar portion that is provided on the deformation portion and that extends in the stacking direction toward the inside of the case when the bar portion is not pressed against the deformation portion and is not in a pressed state. In a pressed state in which the bar portion is pressed against the deformed portion without contacting the wall surface and the deformed portion is deformed, the battery stack is pressed from one end side of the case while the bar portion is not pressed against the deformed portion, thereby inserting the battery stack into the case from one end side of the case, and further, while applying a compressive load in the stacking direction to the battery stack, the bar portion is pressed against the deformed portion, and as the bar portion is pressed against the deformed portion, the tip of the fin portion comes into contact with the inner wall surface of the case, thereby forming a cooling passage between the fin portions of the two sets of seal structures between the inner wall surface of the case and the battery stack.

[0013] The battery pack manufacturing method according to the above aspect can prevent the fins from coming into contact with the case when the battery stack is inserted into the case. Furthermore, the fins can be brought into contact with the inner wall surface of the case while the battery stack is inserted into the case, forming a cooling passage. Therefore, a cooling passage can be provided between the fins of the two sets of sealing structures between the inner wall surface of the case and the battery stack, while preventing damage to the fins or the case due to contact. A spacer with a simple structure is used to form the cooling passage. This allows high-quality battery packs to be manufactured inexpensively.

[0014] In the battery pack manufacturing method of the above aspect, it is further preferable to use a case having a groove extending in the stacking direction at the location of the cooling passage on the inner wall surface, and a spacer having a fixing portion that fixes adjacent battery cells in the width direction of the groove, and having a bar portion pressed against the deformation portion, such that the tips of the fin portions associated with the two sets of sealing structures contact different opposing side surfaces of the groove. This allows the battery stack to be housed in the case, and the fin portions associated with the two sets of sealing structures to contact different opposing side surfaces of the groove. The resulting reaction force then allows the spacers and the battery cells fixed to the spacers to be properly aligned in the stacking direction. In other words, the configuration for forming the cooling passages can even align the battery cells in the battery stack. Therefore, no special configuration for aligning the battery cells is required. This reduces the manufacturing cost of the battery pack.

[0015] In the battery pack manufacturing method of the above aspect, it is further preferable to use a spacer that displaces the fin portion of the deformation portion so as to swing the fin portion when the portion where the fin portion is provided changes from a non-pressed state to a pressed state. This allows the battery stack to be housed in the case, and the fin portion that moves in a swinging manner can be deformed so as to bend overall and contact the inner wall surface of the case. Furthermore, the amount of deformation of the deformation portion can be kept small while ensuring a large amount of movement of the tip of the fin portion. This suppresses deformation of the hollow portion and suppresses damage thereto, while ensuring sufficient clearance between the fin portion and the case when inserting the battery stack into the case member. This prevents damage to the sealing structure and the case and allows for an appropriate cooling passage to be formed.

[0016] In the battery pack manufacturing method of the above aspect, it is further preferable to use a spacer in which the deformation portion has a space formed therein extending in the stacking direction and which deforms when the bar portion is press-fitted into the space. In this way, the deformation portion can be easily deformed by press-fitting the bar portion, while being less susceptible to deformation due to vibration or the like before press-fitting the bar portion. This more reliably prevents the fin portion from coming into contact with the case when inserting the battery stack into the case.

[0017] The battery pack manufacturing method of the above aspect further includes using a case having a floor portion located below the battery stack, an end panel attached to one end of the battery stack in the stacking direction, and an end wall portion located at the other end opposite the end panel attachment location and integral with the floor portion. The battery stack is pressed from one end without the bar portion pressed against the deformation portion, and the other end of the battery stack is pressed against the end wall portion, applying a compressive load to the battery stack in the stacking direction while pressing the bar portion against the deformation portion. The end panel is then attached to the case, and the pressure on the battery stack from the one end is released, bringing the one end of the battery stack into contact with the end panel, thereby sandwiching the battery stack between the end wall portion and the end panel and holding it in the case. In this manner, the battery stack and the end panel can be fixed by the compressive reaction force of the battery stack. That is, for example, fastening or joining to secure the end panel is not required. This reduces the manufacturing cost of the battery pack. [Effects of the Invention]

[0018] According to the disclosed technique, a battery pack and a method for manufacturing the battery pack that can reduce manufacturing costs are provided. [Brief explanation of the drawings]

[0019] [Figure 1] 1 is an external perspective view of a battery pack according to an embodiment; [Figure 2] FIG. 2 is an exploded perspective view of a battery cell and a spacer according to an embodiment. [Figure 3] FIG. 2 is a perspective view of a spacer according to an embodiment. [Figure 4] 2 is a cross-sectional view in the width direction of the battery pack according to the embodiment. FIG. [Figure 5] FIG. 10 is a diagram showing a state before a bar portion is press-fitted into a hollow portion of the spacer according to the embodiment. [Figure 6] FIG. 2 is a diagram illustrating a state before the battery pack according to the embodiment is assembled. [Figure 7]1A and 1B are diagrams illustrating how the battery pack according to the embodiment is assembled. DETAILED DESCRIPTION OF THE INVENTION

[0020] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments embodying the present disclosure will be described in detail with reference to the accompanying drawings.

[0021] In this embodiment, the disclosed technology is applied to a battery pack 1 whose overall configuration is shown in Fig. 1. The battery pack 1 in Fig. 1 has a battery stack 10 housed inside a battery case 20.

[0022] The battery stack 10 is configured to include a plurality of rectangular battery cells 100. The plurality of battery cells 100 in the battery stack 10 are stacked in the X direction shown in FIG. 1. The battery cells 100 shown in FIG. 1 are shown with their width direction aligned in the Y direction and their height direction aligned in the Z direction. The battery pack 1 of this embodiment has two battery stacks 10 arranged side by side in the Y direction. The X and Y directions are horizontal directions, and the Z direction is vertical. The plurality of battery cells 100 in the battery stack 10 are stacked with spacers 150 interposed between them.

[0023] The battery case 20 has a bottom 22 located below the battery stack 10 and side walls 23 extending upward from the bottom 22, and is generally box-shaped with an open top. The battery case 20 has two storage spaces 21 formed by being surrounded by the bottom 22 and the side walls 23. The two battery stacks 10 are housed in the two storage spaces 21, respectively.

[0024] The battery case 20 has a case member 200 and an end panel 250 assembled to the case member 200. The case member 200 has a floor portion 210 that forms the bottom 22. The case member 200 also has an end wall portion 220 that forms the side wall 23 at one end in the stacking direction of the battery cells 100. The floor portion 210 and the end wall portion 220 are part of the case member 200 and are connected to each other.

[0025] The case member 200 has an opening 225 at the end opposite the end wall portion 220 in the stacking direction of the battery cells 100. An attachment portion 226 is provided on the edge of the opening 225 of the case member 200. A plate-shaped end panel 250 is attached to the attachment portion 226 of the case member 200. The attachment portion 226 is a groove-shaped groove provided on the inside of the side wall 23 along the opening 225 of the case member 200. The end panel 250 is attached by being inserted into the attachment portion 226 of the case member 200 from above. The opening 225 of the case member 200 is closed by the end panel 250 attached to the attachment portion 226. A cover member or the like that covers the upper part of the battery pack 1 may be attached as appropriate depending on the actual usage situation, etc.

[0026] The battery stack 10 has end plates 180, 190 at both ends in the stacking direction of the battery cells 100. The end plate on the end panel 250 side is referred to as the first end plate 180, and the end plate on the end wall portion 220 side of the case member 200 is referred to as the second end plate 190.

[0027] The first end plate 180 of this embodiment is composed of a base plate 181 and a pressed plate 182. The pressed plate 182 is located closer to the end panel 250 than the base plate 181. The pressed plate 182 is provided with a pressed portion 183. The pressed portion 183 is a portion that receives pressure when the battery stack 10 is pressed in the stacking direction of the battery cells 100 during the manufacturing process of the battery pack 1.

[0028] The pressed plate 182 is held on the base plate 181 by a plate holding portion 184 provided on the base plate 181. The plate holding portion 184 in this embodiment is a snap fit. The base plate 181 may be made of a material such as an insulating resin. The pressed plate 182 has a higher strength than the base plate 181. The pressed plate 182 may be made of a material such as a metal.

[0029] Furthermore, end panel 250 of this embodiment has an upper surface portion 251 at its upper part. Upper surface portion 251 is a portion that receives downward pressure when end panel 250 is attached to attachment portion 226. End panel 250 has a recess 252. Recess 252 is provided in a position corresponding to pressed portion 183 of first end plate 180. Recess 252 has a notch shape that is formed from the lower end of end panel 250 to the upper side. Recess 252 has a shape that allows end panel 250 to be attached to attachment portion 226 while pressing first end plate 180.

[0030] A cooling passage 300 is provided between the battery stack 10 and the battery case 20 in the battery pack 1. The cooling passage 300 is a space through which a fluid for cooling the battery cells 100 passes in the stacking direction of the battery cells 100. The cooling passage 300 in this embodiment is provided in the lower part of the battery pack 1.

[0031] 2 is an exploded perspective view of a battery cell 100 and a spacer 150 to which the battery cell 100 is assembled. The battery cell 100 of this embodiment uses a conductive metal for the exterior. Two pole terminals 102 are provided on the top surface 101 of the battery cell 100. One of the two pole terminals 102 is a positive electrode and the other is a negative electrode.

[0032] 2 shows a bus bar 30 for electrically connecting the pole terminals 102 of the multiple battery cells 100 to each other. As shown in FIG. 1, the bus bar 30 in the battery pack 1 is connected to all of the battery cells 100. Therefore, in the battery pack 1, it is preferable that the positions of the pole terminals 102 of the multiple battery cells 100 are aligned. Specifically, it is preferable that the positions of the pole terminals 102 in the width direction are constant for all of the multiple battery cells 100 in the battery pack 1. This is because, when the multiple pole terminals 102 are aligned in the stacking direction of the battery cells 100, the pole terminals 102 can be easily and appropriately connected by the bus bar 30.

[0033] The spacers 150 are made of an insulating material. For example, insulating resin can be used as the material for the spacers 150. The spacers 150 have recesses 151 on the side of the battery cells 100 to be assembled. In the battery stack 10, the battery cells 100 are fitted into the recesses 151 of the spacers 150. This allows the battery cells 100 and the spacers 150 to be assembled and fixed to each other. In other words, the spacers 150 fix adjacent battery cells 100 in the width direction by fixing surfaces 152 located at both ends of the battery cells 100 in the width direction.

[0034] In the battery stack 10, multiple assemblies of battery cells 100 and spacers 150 are arranged in the X direction. As a result, in the battery stack 10, multiple battery cells 100 are stacked with the spacers 150 interposed between them. The spacers 150 insulate the battery cells 100 from one another in the battery stack 10.

[0035] Two alignment protrusions 153 are also provided below the spacer 150. The two alignment protrusions 153 are arranged with a gap between them in the width direction of the battery cell 100. Furthermore, two seal portions 160 are provided between the two alignment protrusions 153. The two seal portions 160 provided on the spacer 150 have symmetrical shapes with respect to the width direction of the battery cell 100.

[0036] The sealing portion 160 has a bar portion 161 that extends in the stacking direction of the battery cells 100. In the battery stack 10, the bar portion 161 protrudes toward the adjacent spacer 150 via the battery cell 100 fixed to the spacer 150. The bar portion 161 also has a protrusion 163 on its underside 162. The protrusion 163 is provided continuously along the bar portion 161 in the stacking direction of the battery cells 100. Figure 2 shows the dimension L1 of the bar portion 161. The dimension L1 is the length of the bar portion 161, including the protrusion 163, in the height direction of the battery cell 100.

[0037] FIG. 3 shows the side opposite the recessed portion 151 of the spacer 150. As shown in FIG. 3, the sealing portion 160 has a hollow portion 171 on the side opposite the bar portion 161. The hollow portion 171 has a space 172 formed therein that extends in the stacking direction of the battery cells 100. In the battery stack 10, the bar portion 161 of another spacer 150 is press-fitted into the space 172 of the hollow portion 171. FIG. 3 also shows the dimension L2 of the hollow portion 171. The dimension L2 is the length of the space 172 in the height direction of the battery cell 100. The dimension L2 of the space 172 of the hollow portion 171 is smaller than the dimension L1 of the bar portion 161. Therefore, when the bar portion 161 is press-fitted into the space 172, the hollow portion 171 is deformed so as to expand in the height direction of the battery cell 100.

[0038] Of the outer surfaces of the hollow portion 171, a lower surface 173 located on the lower side is provided with fin portions 174. The fin portions 174 are provided continuously along the hollow portion 171 in the stacking direction of the battery cells 100.

[0039] FIG. 4 is a cross-sectional view of the battery pack 1 in the width direction. FIG. 4 shows only one of the two battery stacks 10 in the battery pack 1. The case member 200 has inner wall surfaces 201 that form the storage space 21, including side inner wall surfaces 202 and a bottom inner wall surface 203. The bottom inner wall surface 203 is the upper surface of the floor portion 210. The bottom inner wall surface 203 is the surface that forms the lower side of the storage space 21. The side inner wall surfaces 202 are the surfaces that form both ends of the storage space 21 in the width direction of the battery cells 100. In other words, there are two side inner wall surfaces 202 for one storage space 21. These two side inner wall surfaces 202 face each other. In the battery pack 1 of this embodiment, the cooling passage 300 is provided between the bottom inner wall surface 203 of the case member 200 and the lower surface 12 of the battery stack 10.

[0040] In this embodiment, ventilation grooves 240 extending in the stacking direction of the battery cells 100 are provided in the bottom inner wall surface 203 of the case member 200 at the location of the cooling passage 300. The ventilation grooves 240 extend from the end panel 250 side to the end wall portion 220. In the battery pack 1, the battery cells 100 are cooled by air flowing through the cooling passage 300. This suppresses a rise in the temperature of the battery cells 100.

[0041] As shown in Figure 4, two alignment rail sections 230 extending in the stacking direction of the battery cells 100 are provided on the bottom inner wall surface 203, which is the upper surface of the floor section 210 of the case member 200. The alignment rail sections 230 extend from the end panel 250 side to the end wall section 220. The ventilation groove 240 is located between the two alignment rail sections 230.

[0042] Furthermore, the two alignment rail portions 230 are located slightly inside the two alignment protrusions 153 of the spacer 150 in the width direction of the battery cells 100. Therefore, when the spacer 150 rotates so that one of the two alignment protrusions 153 moves more in the stacking direction of the battery cells 100 than the other, the alignment protrusion 153 comes into contact with the alignment rail portion 230. In other words, the alignment protrusions 153 fit into the alignment rail portion 230, preventing the spacer 150 and the battery cells 100 from rotating relative to the case member 200 around a rotation axis that extends in the height direction of the battery cells 100.

[0043] The ventilation groove 240 has two groove side surfaces 241 positioned opposite each other and a groove bottom surface 242 connecting the two groove side surfaces 241. Both the groove side surfaces 241 and the groove bottom surface 242 are part of the bottom inner wall surface 203 of the case member 200. The width and depth directions of the ventilation groove 240 are the same as the width and height directions of the battery cell 100, respectively.

[0044] As shown in FIG. 4 , in the battery pack 1, both of the two seal portions 160 of the spacer 150 are located between the two groove side surfaces 241 of the ventilation groove 240. A bar portion 161 is press-fitted into the hollow portion 171 of the seal portion 160. By press-fitting the bar portion 161 into the hollow portion 171, the bar portion 161 is pressed against the inner surface of the hollow portion 171. The bar portion 161 press-fitted into the hollow portion 171 is the bar portion 161 of another spacer 150 that is adjacent to the spacer 150 having the hollow portion 171 with a battery cell 100 interposed therebetween. The protrusion 163 of the bar portion 161 is provided in the center of the battery cell 100 in the width direction. Meanwhile, the fin portion 174 of the hollow portion 171 is provided in a base portion 175 that is located outside the protrusion 163 in the width direction of the battery cell 100. Therefore, in the press-fit state where the bar portion 161 is press-fitted, the base portion 175 of the hollow portion 171 is displaced so as to swing the fin portion 174 compared to the non-press-fit state where the bar portion 161 is not press-fitted. The displacement of the base portion 175 of the hollow portion 171 is a displacement in the direction of bringing the tip 176 of the fin portion 174 closer to the groove side surface 241.

[0045] In this embodiment, the two hollow portions 171 are each displaced so that the tips 176 of the two fin portions 174 are open in the width direction of the ventilation groove 240. As a result, the spacer 150 has the tips 176 of the two fin portions 174 in contact with different groove side surfaces 241. That is, for two spacers 150 adjacent to each other with a battery cell interposed therebetween, the gap between the underside 12 of the battery stack 10 and the ventilation groove 240 is blocked by a sealing structure 170 formed by one bar portion 161 and the other hollow portion 171 and fin portion 174. That is, the cooling passage 300 is formed between the fin portions 174 of the two sets of sealing structures 170 between the ventilation groove 240 provided in the bottom inner wall surface 203 of the case member 200 and the underside 12 of the battery stack 10. In the cooling passage 300, the tip 176 of the fin portion 174 is in contact with the groove side surface 241, which prevents the air flowing through the cooling passage 300 in the stacking direction of the battery cells 100 from leaking in the width direction of the battery cells 100.

[0046] In the battery stack 10, when the bar portion 161 is press-fitted into the hollow portion 171, the fin portions 174 adjacent to each other in the stacking direction of the battery cells 100 are in close contact with each other so that no gaps are formed between them. This prevents air flowing through the cooling passage 300 from leaking between the fin portions 174 adjacent to each other in the stacking direction of the battery cells 100. Alternatively, the fin portions 174 adjacent to each other in the stacking direction of the battery cells 100 may each be provided with an overlap portion that overlaps with the adjacent fin portion 174. This makes it possible to more appropriately prevent air from leaking from the cooling passage 300.

[0047] Fig. 5 shows hollow portion 171 before bar portion 161 is press-fitted into space 172. As shown in Fig. 5, in spacer 150, in a non-press-fit state before bar portion 161 is press-fitted into hollow portion 171, tip end 176 of fin portion 174 is not in contact with case member 200, and a gap is formed therebetween. In seal structure 170, when bar portion 161 is press-fitted into hollow portion 171, hollow portion 171 is deformed into a press-fit state, and tip end 176 of fin portion 174 comes into contact with groove side surface 241 of ventilation groove 240 of case member 200, as shown in Fig. 4.

[0048] Next, a manufacturing method of the battery pack 1 of this embodiment will be described with reference to Figs. 6 and 7. Fig. 6 is a diagram showing the battery stack 10, case member 200, and end panel 250 before they are assembled. Fig. 7 is a diagram showing the battery stack 10, case member 200, and end panel 250 being assembled. Both Figs. 6 and 7 are schematic cross-sectional views taken along the line AA in Fig. 1. For example, Figs. 6 and 7 omit details of the battery cells 100 and spacers 150 in the battery stack 10. In this embodiment, the battery pack 1 is manufactured by first housing the battery stack 10 in the case member 200, and then assembling the end panel 250.

[0049] As shown in FIG. 6, the battery stack 10 is constructed by stacking multiple assemblies of battery cells 100 and spacers 150 before they are housed in the case member 200. As described above, the spacer 150 is provided with a seal portion 160 having a bar portion 161, a hollow portion 171, and a fin portion 174. The seal portion 160 faces downward. A first end plate 180 is stacked on the end of the battery stack 10 that faces the end panel 250. A second end plate 190 is stacked on the end of the battery stack 10 that faces the end wall portion 220.

[0050] The orientation of multiple assemblies of battery cells 100 and spacers 150 is the same in the stacking direction of the battery cells 100. In the battery stack 10 of this embodiment, the bar portion 161 faces the first end plate 180, and the hollow portion 171 faces the second end plate 190. In this embodiment, the second end plate 190 is provided with a bar portion 161 that is press-fitted into the hollow portion 171 of the spacer 150 that is located closest to the second end plate 190 in the stacking direction of the battery cells 100. The spacer 150 that is located closest to the first end plate 180 in the stacking direction of the battery cells 100 does not have a bar portion 161. This is because there are no other spacers 150 that have a hollow portion 171 into which the bar portion 161 can be press-fitted. The spacer 150 that is located closest to the first end plate 180 may be provided with a bar portion 161.

[0051] Before being housed in the case member 200, the battery stack 10 has the seal structure 170 in an unpressed state. That is, before assembly, the bar portion 161 of one of two spacers 150 adjacent to each other across a battery cell 100 is not press-fit into the hollow portion 171 of the other spacer 150. Therefore, the distance between the spacers 150 is wider when the seal structure 170 is unpressed than when it is pressed. As shown in FIG. 6 , the battery stack 10 is assembled into the case member 200 by housing the battery stack 10 inside the case member 200 from the side of the mounting portion 226 of the end panel 250 of the case member 200.

[0052] The battery stack 10 can be accommodated in the case member 200 by moving at least one of the battery stack 10 and the case member 200 toward the other. In this embodiment, while the case member 200 is fixed, the battery stack 10 is pressed from the first end plate 180 side by the pressing portion 400, as shown in FIG. 7(A). The pressing portion 400 presses the pressed portion 183 of the first end plate 180. In this way, the battery stack 10 is moved toward the end wall portion 220 and is accommodated in the case member 200 until the second end plate 190 comes into contact with the end wall portion 220.

[0053] When the battery stack 10 is accommodated in the case member 200, the battery stack 10 moves along the bottom inner wall surface 203 of the case member 200. As described above, the bottom inner wall surface 203 of the case member 200 is provided with the alignment rail portion 230, and the spacers 150 of the battery stack 10 are provided with the alignment protrusions 153 that fit into the alignment rail portion 230. This makes it possible to prevent the battery cells 100 and the spacers 150 from rotating in the case member 200 when the battery stack 10 is accommodated in the case member 200. In other words, the battery stack 10 can be smoothly accommodated in the case member 200 without meandering in the stacking direction of the battery cells 100.

[0054] 7(A), in this embodiment, the bar portion 161 is not press-fit into the hollow portion 171 until the battery stack 10 is accommodated in the case member 200 from the outside thereof and the second end plate comes into contact with the end wall portion 220. In other words, the seal structure 170 is maintained in a non-press-fit state from the time the battery stack 10 enters the case member 200 from the outside thereof until the time the battery stack 10 comes into contact with the end wall portion 220. Therefore, as described in FIG. 5, the fin portion 174 of the seal structure 170 can be accommodated in the case member 200 until the battery stack 10 comes into contact with the end wall portion 220 without contacting the case member 200.

[0055] The battery stack 10 that has come into contact with the end wall portion 220 is further pressed by the pressing portion 400. That is, the second end plate 190 on the opposite side of the battery stack 10 from the side receiving the pressure is pressed against the end wall portion 220, while being compressed in the stacking direction of the battery cells 100. This pressing applies a compressive load to the battery stack 10 in the stacking direction of the battery cells 100.

[0056] Furthermore, by continuing to press the battery stack 10 with the pressing portion 400 even after the second end plate has contacted the end wall portion 220, the sealing structure 170 is brought into a press-fit state as shown in FIG. 7(B). That is, for two spacers 150 adjacent to each other with a battery cell 100 interposed between them, the bar portion 161 provided on one of the spacers is press-fit into the hollow portion 171 provided on the other spacer. This deforms the hollow portion 171, and brings the tip 176 of the fin portion 174 into contact with the groove side surface 241. This allows the cooling passage 300 described in FIG. 4 to be formed. Furthermore, by bringing the sealing structure 170 into the press-fit state, the gap between the spacers 150 becomes narrower than in the non-press-fit state before the press-fit state was reached.

[0057] Furthermore, while the pressing portion 400 is applying a compressive load to the battery stack 10, the end panel 250 is attached to the mounting portion 226. The end panel 250 can be attached to the mounting portion 226 by pressing the upper surface portion 251 toward the mounting portion 226. Furthermore, the end panel 250 has a relief portion 252 formed at the location of the pressing portion 400, so that it does not interfere with the pressing portion 400.

[0058] Thereafter, the pressure applied by the pressing unit 400 is released. When the pressure applied by the pressing unit 400 is released, the battery stack 10, which has been compressed and shrunk in the stacking direction of the battery cells 100, expands. As a result, the first end plate 180 of the battery stack 10, which has now been released from compression, comes into contact with the end panel 250. In this way, the battery pack 1 is manufactured. After that, the bus bar 30 is attached to the battery stack 10 of the battery pack 1 as appropriate.

[0059] Even if the battery stack 10 expands from the compressed state to contact the end panel 250 after the compression is released, the battery stack 10 remains in a state that is smaller than the uncompressed state before being accommodated in the case member 200. That is, each battery cell 100 in the battery stack 10 is compressed in the stacking direction. Therefore, the battery stack 10 in the battery pack 1 is sandwiched between the end wall portion 220 and the end panel 250. This allows the battery stack 10 to be held within the accommodation space 21 of the battery case 20. Furthermore, the end panel 250 in the battery pack 1 is pressed against the outer surface of the groove-shaped attachment portion 226 in the stacking direction of the battery cells 100 in a direction away from the end wall portion 220 due to the compression reaction force of the battery stack 10. This prevents the end panel 250 from falling off the attachment portion 226, etc. This appropriately prevents the battery stack 10 and the end panel 250 from falling off the case member 200, etc. That is, no special fastening or joining is required to fix the battery stack 10 or the end panel 250. Therefore, the battery pack 1 requires fewer parts, which reduces manufacturing costs.

[0060] Furthermore, in this embodiment, as described above, the battery stack 10 can be housed in the case member 200 until it contacts the end wall portion 220 without the fin portion 174 of the seal structure 170 coming into contact with the case member 200. This prevents the fin portion 174 from interfering with the case member 200. In other words, damage to the fin portion 174 and the case member 200 can be prevented. After the battery stack 10 is housed in the case member 200 until it contacts the end wall portion 220, the seal structure 170 can be press-fitted to form the cooling passage 300. This allows the cooling passage 300 to be appropriately formed using a spacer 150 with a simple configuration.

[0061] Unlike the present embodiment, a seal structure using an elastic material such as a sponge may be used instead of the seal structure 170. Specifically, for example, a sponge may be fixed to the inner wall surface of the bottom of the case member, with the sponge being high enough to contact the underside of the battery stack. To ensure a certain level of airtightness using the sponge, the sponge must be high enough to be pressed against the underside of the battery stack. However, in such a configuration, the sponge comes into contact with the battery stack when the battery stack is moved in the stacking direction of the battery cells and inserted into the case member. The sponge that comes into contact with the battery stack may be peeled off or damaged. Furthermore, the sponge tends to generate large frictional resistance, which may cause the battery cells to tip over when the battery stack is inserted into the case member. In contrast, in the present embodiment, the fin portion 174 can be brought into contact with the inner wall surface 201 of the case member 200 after the battery stack 10 is inserted into the case member 200. Therefore, the battery pack 1 of the present embodiment does not suffer from the above-described problems associated with the use of a seal structure such as a sponge.

[0062] Furthermore, the case member 200 of this embodiment has ventilation grooves 240 formed on the bottom inner wall surface 203. The spacer 150 has fixing surfaces 152 that fix adjacent battery cells 100 in the width direction. The width direction of the battery cells 100 is the same as the width direction of the ventilation grooves 240. Furthermore, with the bar portions 161 press-fitted into the hollow portions 171, the two sets of seal structures 170 associated with the spacer 150 have their tips 176 of the two fin portions 174 contact different groove side surfaces 241 of the two groove side surfaces 241 of the ventilation grooves 240. In other words, with the two sets of seal structures 170 in a press-fit state, the two fin portions 174 each receive a reaction force from the opposing different groove side surfaces 241. These reaction forces allow the width direction position of all the battery cells 100 to be stably determined relative to the ventilation grooves 240. That is, the battery cells 100 can be aligned without meandering in the stacking direction. In addition, by increasing the cross-sectional area of ​​the cooling passage 300 by using the ventilation grooves 240, the flow rate of air flowing through the cooling passage 300 can be made sufficient.

[0063] In this embodiment, the base 175 of the spacer 150, on which the fin portion 174 is provided in the hollow portion 171, displaces so as to swing the fin portion 174 when the bar portion 161 is press-fitted into the hollow portion 171. Therefore, the amount of displacement of the base 175 can be small. That is, a large amount of movement of the tip 176 of the fin portion 174 can be ensured while suppressing deformation of the hollow portion 171. This reduces the pressing force required to press-fit the bar portion 161 into the hollow portion 171. Furthermore, the amount of deformation of the hollow portion 171 can be reduced, thereby suppressing damage to the hollow portion 171. Furthermore, by ensuring a large amount of movement of the tip 176 of the fin portion 174, a sufficient clearance can be ensured between the fin portion 174 and the case member 200 when the battery stack 10 is inserted into the case member 200. Furthermore, for example, if hollow portion 171 into which bar portion 161 is press-fitted is significantly deformed, fin portion 174 also moves significantly toward inner wall surface 201 of case member 200. Even in such a case, fin portion 174, which has moved in a swinging manner, can be deformed so as to bend overall when it comes into contact with side inner wall surface 202. This makes it possible to prevent damage to seal structure 170 and the like, and to properly form cooling passage 300.

[0064] As described above in detail, according to this embodiment, the battery pack 1 includes a battery stack 10 and a battery case 20. The battery stack 10 is formed by stacking a plurality of battery cells 100 with spacers 150 interposed therebetween. The battery case 20 houses the battery stack 10 from the mounting portion 226 side of the end panel 250, which is one end side in the stacking direction of the battery cells 100. In the battery pack 1, a cooling passage is provided between the battery stack 10 and the bottom inner wall surface 203 of the case member 200 constituting the battery case 20, allowing air to pass in the stacking direction of the battery cells 100 to cool the battery cells 100. The spacers 150 have two sets of sealing structures 170, each consisting of a bar portion 161, a hollow portion 171, and a fin portion 174, for two adjacent spacers 150 separated by a battery cell 100. The bar portion 161 is provided on one spacer 150 and extends in the stacking direction of the battery cells 100 toward the other spacer 150. The hollow portion 171 is provided in the other spacer 150, and defines a space 172 extending in the stacking direction of the battery cells 100. A bar portion 161 provided in one of the spacers 150 is press-fitted into the space 172. The fin portion 174 is provided on a lower surface 173 of the outer surface of the hollow portion 171, and a tip 176 thereof contacts a bottom inner wall surface 203 of the case member 200. The cooling passage 300 is formed between the fin portions 174 of the two sets of seal structures 170 between the bottom inner wall surface 203 of the case member 200 and the battery stack 10. In addition, in a non-press-fit state where the bar portion 161 is not press-fitted into the hollow portion 171, the tip 176 of the fin portion 174 of the spacer 150 does not contact the inner wall surface 201 of the case member 200. On the other hand, in a press-fit state in which the bar portion 161 is press-fitted into the hollow portion 171 and the hollow portion 171 is deformed, the tip 176 comes into contact with the bottom inner wall surface 203 of the case member 200. Then, the battery pack 1 is inserted into the case member 200 by pressing the battery stack 10 from the first end plate 180 side in a state in which the bar portion 161 is not press-fitted into the hollow portion 171. Furthermore, the bar portion 161 is press-fitted into the hollow portion 171 while applying a compressive load to the battery stack 10 in the stacking direction of the battery cells 100. This forms a cooling passage 300 for the battery pack 1.The spacer 150 does not have a complicated seal structure 170 for forming the cooling passage 300. In other words, the configuration for providing the cooling passage 300 is simple, and the cost of each component can be reduced. This allows for the realization of a battery pack 1 and a manufacturing method thereof that can reduce manufacturing costs.

[0065] The above-described embodiments and examples are merely illustrative and do not limit the present disclosure in any way. Therefore, the present disclosure can be naturally improved and modified in various ways without departing from the spirit and scope of the present disclosure.

[0066] For example, in the above embodiment, the mounting portion for attaching the end panel is described as being composed of a single groove-shaped mounting portion. However, the mounting portion of the end panel may be provided with multiple mounting portions at different positions in the stacking direction of the battery cells. The end panel may be attached to one of the multiple mounting portions depending on the length of the compressed battery stack in the stacking direction of the battery cells. The relationship between the length of the compressed battery stack and the mounting portion for attaching the end panel may be determined in advance. This allows the battery stack to be appropriately compressed in the stacking direction of the battery cells. It also allows the reaction force that the end panel receives from the battery stack to be appropriate.

[0067] In the above embodiment, the tip of the fin portion of the seal structure is described as contacting the bottom inner wall surface of the case member. However, for example, the location where the tip of the fin portion contacts may be any inner wall surface of the case member, including a side inner wall surface. In the above embodiment, an example is described in which a groove is provided in the location of the cooling passage on the inner wall surface of the case member. However, for example, the location of the cooling passage of the case member may be a flat inner wall surface without a groove. In this case, the fin portion of the seal structure in the pressed state may contact the flat inner wall surface.

[0068] In the above embodiment, an example was described in which the battery cells were assembled to the spacers on the end wall side of the battery cells. However, the battery cells may also be assembled to the spacers on the end panel side of the battery cells. In the above embodiment, the same spacers were used, and the cooling passages were described as being formed continuously from the end panel side to the end wall side. However, for example, a configuration could be adopted in which a spacer without fins is provided in some areas, and the cooling passages are branched at those positions.

[0069] Furthermore, for example, when the battery stack is housed in the case member, the tips of the bar portions may partially enter the space of the hollow portion before the battery stack abuts against the end wall portion, as long as the fin portions do not come into contact with the inner wall surface of the case member. Then, once the battery stack abuts against the end wall portion, the bar portions may be press-fitted into the hollow portion, and the tips of the fin portions may come into contact with the inner wall surface of the case member.

[0070] In the above embodiment, the deformation portion of the spacer that deforms when the bar portion is pressed against it is a hollow portion with an internal space. However, the deformation portion that deforms when the bar portion is pressed against it does not necessarily have to be hollow. That is, the deformation portion provided with the fin portion may be deformed when the bar portion is pressed against it, so that the fin portion can contact the inner wall surface of the case member. Specifically, for example, a spacer may be used in which the two hollow portions according to the above embodiment are replaced with two deformation portions shaped as if the wall portions located on the inner side in the width direction of the battery cell were removed from each of the two hollow portions. Even in a spacer with such deformation portions, the fin portion can be changed from a non-pressed state before the bar portion is pressed against the deformation portion to a pressed state in which the bar portion is pressed against the deformation portion, thereby changing the state in which the fin portion is not in contact with the inner wall surface of the case member to a contact state. Note that adopting a shape similar to the hollow portion according to the above embodiment for the deformation portion can make it less susceptible to deformation due to vibration or the like before the bar portion is pressed against it. In other words, vibration of the fin portion can be suppressed, and the fin portion can be more reliably prevented from contacting the case member when inserting the battery stack into the case member. Furthermore, even if the deforming portion has a hollow shape, it can be easily deformed by press-fitting the bar portion.

[0071] In the above embodiment, the sealing structure is described as an example in which a protrusion is formed on the bar portion and the hollow portion where the protrusion of the bar portion contacts is flat. However, for example, a protrusion protruding toward the bar portion may be provided within the space of the hollow portion, and the bar portion may not have a protrusion. In other words, the shape of the bar portion and the hollow portion may be configured so that the hollow portion is deformed when the bar portion is press-fitted, and as a result, the fin portion provided on the outer surface of the hollow portion moves so that its tip comes into contact with the inner wall surface of the case member.

[0072] Furthermore, for example, the fluid flowing through the cooling passage is not limited to air, and may be a gas other than air. Furthermore, there is no particular limitation on the type of battery (nickel-metal hydride battery, lithium-ion battery, etc.) to which the above embodiment is applicable. [Explanation of symbols]

[0073] 1 battery pack 10 Battery stack 12 Bottom side 20 Battery case 100 battery cells 150 spacer 161 Bar Section 170 Seal structure 171 Hollow part 174 Fin section 176 Tip 200 Case material 203 Bottom inner wall 240 Ventilation groove 241 Groove side 250 End Panel 300 Cooling passage

Claims

1. A battery pack comprising: a battery stack formed by stacking a plurality of battery cells with spacers interposed therebetween; and a case that houses the battery stack from one end side in the stacking direction of the battery cells, wherein a cooling passage is provided between an inner wall surface of the case and the battery stack, through which a fluid for cooling the battery cells passes in the stacking direction; The spacers are arranged such that two adjacent spacers are spaced apart from each other by the battery cell. a bar portion provided on one side and extending toward the other side in the stacking direction; a deformation portion provided on the other side and deformed by the bar portion provided on the one side being pressed against the deformation portion; a fin portion provided at the deformation portion, the tip of the fin portion being in contact with the inner wall surface of the case; The cooling passage is formed between the fin portions of the two sets of the sealing structures between the inner wall surface of the case and the battery stack.

2. 2. The battery pack according to claim 1, the case has an inner wall surface provided with a groove extending in the stacking direction at a location of the cooling passage, The spacer is a fixing portion that fixes the adjacent battery cells in the width direction of the groove, The battery pack has two sets of fin portions each having a tip end in contact with a different one of two opposing side surfaces of the groove portion.

3. 3. The battery pack according to claim 1 or 2, The deformation portion is deformed by the bar portion being pressed against the battery pack so as to swing the fin portion compared to when the bar portion is not pressed against the battery pack.

4. 3. The battery pack according to claim 1 or 2, The deformation portion has a space formed therein that extends in the stacking direction, and the bar portion is press-fitted into the space, thereby causing the battery pack to deform.

5. 3. The battery pack according to claim 1 or 2, The case is a floor portion located below the battery stack; an end panel attached to one end side in the stacking direction; an end wall portion located on the other end side opposite to the attachment point of the end panel and integrally connected to the floor portion; The battery pack includes a battery stack sandwiched between the end panel and the end wall portion and held in the case.

6. A method for manufacturing a battery pack including a battery stack formed by stacking a plurality of battery cells with spacers interposed therebetween, and a case that houses the battery stack from one end side in a stacking direction of the battery cells, and a cooling passage that passes a fluid for cooling the battery cells in the stacking direction between an inner wall surface of the case and the battery stack, As the spacer, two adjacent spacers disposed between the battery cells are a bar portion provided on one side and extending toward the other side in the stacking direction; a deformation portion provided on the other side and deformed when the bar portion provided on the one side is pressed against the deformation portion; a fin portion provided on the deformation portion, the fin portion having a tip that does not contact the inner wall surface of the case in a non-pressure-contact state where the bar portion is not pressed against the deformation portion, and a tip that contacts the inner wall surface of the case in a pressurized state where the bar portion is pressed against the deformation portion and the deformation portion is deformed, The battery stack is inserted into the case from the one end side of the case by pressing the battery stack from one end side with the bar portion not being pressed against the deformation portion, and further, the bar portion is pressed against the deformation portion while applying a compressive load to the battery stack in the stacking direction; A method for manufacturing a battery pack in which the bar portion is pressed against the deformation portion, thereby bringing the tip of the fin portion into contact with the inner wall surface of the case and forming the cooling passage between the fin portions of the two sets of the sealing structure between the inner wall surface of the case and the battery stack.

7. 7. A method for manufacturing a battery pack according to claim 6, comprising the steps of: The case has a groove portion extending in the stacking direction provided in an inner wall surface at a location of the cooling passage, As the spacer, a fixing portion that fixes the adjacent battery cells in the width direction of the groove, A method for manufacturing a battery pack in which the bar portion is pressed against the deformation portion, and the tips of the fin portions of the two sets of the sealing structures are brought into contact with different of two opposing side surfaces of the groove portion.

8. A method for manufacturing a battery pack according to claim 6 or 7, comprising the steps of: A method for manufacturing a battery pack using a spacer in which the portion of the deformation portion where the fin portion is provided displaces so as to oscillate the fin portion when it changes from the non-pressurized state to the pressed state.

9. A method for manufacturing a battery pack according to claim 6 or 7, comprising the steps of: A method for manufacturing a battery pack using, as the spacer, a space formed in the deformation portion that extends in the stacking direction and that deforms when the bar portion is pressed into the space.

10. A method for manufacturing a battery pack according to claim 6 or 7, comprising the steps of: In the above case, a floor portion located below the battery stack; an end panel attached to one end side in the stacking direction; The end panel is attached to the other end of the building, and the end wall is integral with the floor. pressing the battery stack from one end side in a state in which the bar portion is not pressed against the deformation portion, thereby pressing the other end side of the battery stack against the end wall portion and applying a compressive load in the stacking direction to the battery stack while pressing the bar portion against the deformation portion; attaching the end panel to the case; A method for manufacturing a battery pack, in which the pressure on one end of the battery stack is released and the one end in the stacking direction is brought into contact with the end panel, so that the battery stack is held in the case while being sandwiched between the end wall portion and the end panel.

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