Battery pack and method of manufacturing the battery pack

Abstract

To provide a battery pack capable of reducing a manufacturing cost, and provide a manufacturing method of the battery pack.SOLUTION: A battery pack 1 includes: a battery stack 10 in which a plurality of battery cells 100 is laminated; and a case member 200 housing the battery stack 10. The case member 200 includes: an integrated end wall part 220 that is positioned at an end part of one of a lamination direction of the battery stack 10, and is connected to a floor part; and a third attachment formation part 233 that is positioned at an end part on the side opposite to the end wall part 220, and to which a panel-like member is attached. The battery stack 10 is held by the case member 200 while being nipped by the end wall part 220 and an end panel 250 on the other end side. The end panel 250 is fixed to a third attachment shape part 233 with a pressure toward a direction separated from the end wall part 220 by a compression stress of the battery stack 10.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] An example of a conventional battery pack is described in Patent Document 1. In this battery pack, end plates are placed on both ends of a battery stack formed by stacking battery cells in the stacking direction, and the end plates are connected to each other by a bind bar. The bind bar is provided with an expansion / contraction mechanism that expands and contracts in the stacking direction of the battery cells, allowing the expansion / contraction mechanism of the bind bar to be fixed at any position. This allows the battery stack to be fixed while applying appropriate pressure in the stacking direction, even if there is variation in the length of the battery stack in the stacking direction. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2012-243534 Summary of the Invention [Problem to be solved by the invention]

[0004] The above-described conventional techniques have the problem of increasing the manufacturing costs of battery packs. For example, if the bind bar is provided with an extension function to accommodate individual differences in the length of the battery stack in the stacking direction, a component for the extension function and a component for fixing the extension function after adjusting the extension function are required. This increases the number of components in the battery pack. Furthermore, as the number of components increases, the adjustment and assembly processes tend to become more complicated.

[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 in which multiple battery cells are stacked, and a case member that houses the battery stack, wherein the case member has a floor portion located below the battery stack, an end wall portion located at one end of the battery stack in the stacking direction and connected to the floor portion as an integral part, and an attachment shape portion located at the end opposite the end wall portion and for attaching a panel-like member, the battery pack having an end panel attached to the attachment shape portion, the battery stack being held by the case member while being sandwiched between the end wall portion and the end panel, and the end panel being pressed against the attachment shape portion in a direction away from the end wall portion by the compressive reaction force of the battery stack and fixed thereto.

[0007] In the battery pack of the above embodiment, the battery stack and the end panel are fixed together by the compressive reaction force of the battery stack. That is, for example, fastening or joining to fix the end panel is not required. Therefore, the battery pack of this embodiment can be manufactured inexpensively.

[0008] In the battery pack of the above aspect, it is further preferable that the case member has mounting shapes formed at multiple locations on the end opposite the end wall portion, and the end panel is attached to one of the multiple mounting shapes. In this way, the position of the end panel is appropriately adjusted according to individual differences in the length of the battery stack in the stacking direction. No special parts or processes are required to adjust the position of the end panel according to individual differences in the length of the battery stack in the stacking direction. Therefore, even when there is a large difference in the length of the battery stack in the stacking direction, manufacturing costs are reduced.

[0009] In the battery pack of the above aspect, it is further preferable that the floor portion is formed with an alignment portion that aligns the battery cells of the battery stack in the stacking direction, and that the battery stack includes a fitting member that fits into the alignment portion along with the plurality of battery cells. In this way, a battery pack in which the battery cells are aligned in the stacking direction can be achieved with an inexpensive configuration using the alignment portion and the fitting member.

[0010] In the battery pack of the above aspect, the battery stack further includes end plates located outward of the battery cells located at both ends in the stacking direction, and a first separation prevention portion is provided at the bottom of the end panel to prevent a first end plate, which is an adjacent end plate, from moving upward and separating from the case member, and the first end plate is preferably provided with a first catch portion that catches on the first separation prevention portion when it moves upward. This prevents the first end plate from moving upward and separating from the case member. In other words, a battery pack can be achieved in which separation of the battery stack from the case member is appropriately prevented.

[0011] In the battery pack of the above aspect, the end wall portion may further include a second separation prevention portion that prevents the adjacent second end plate from moving upward and separating from the case member, and the second end plate may be provided with a second catch portion that catches on the second separation prevention portion when it moves upward. This prevents both the first end plate and the second end plate from moving upward and separating from the case member. In other words, a battery pack in which the battery stack is appropriately prevented from separating from the case member can be achieved.

[0012] In the battery pack of the above aspect, the second separation prevention portion is preferably provided at a position higher than the first separation prevention portion, and the length of the first hook portion is preferably longer than the length of the second hook portion in the stacking direction of the battery stack. This more reliably prevents both the first end plate and the second end plate from moving upward and separating from the case member.

[0013] In the battery pack of the above aspect, the battery stack further includes end plates located outside the battery cells located at both ends in the stacking direction, the case member includes a plurality of fixed portions in the stacking direction of the battery stack that are fixed to the external fixing portions, the center of gravity of the battery pack is located closer to the eccentric fixed portion of one of the fixed portions at both ends than the midpoint between the end fixed portions in the stacking direction of the battery stack, and one of the end wall portions and the end panel, which is farther from the eccentric fixed portion in the stacking direction of the battery stack, is provided with a separation prevention portion that prevents the adjacent end plate from moving upward and detaching from the case member, and the end plate adjacent to the one portion is preferably provided with a catch portion that catches on the separation prevention portion when it moves upward. In this way, the end plate at both ends in the stacking direction of the battery stack that is prone to movement due to vibration is prevented from detaching from the case member. In other words, a battery pack can be achieved in which the battery stack is appropriately prevented from detaching from the case member.

[0014] Another aspect of the disclosed technology is a method for manufacturing a battery pack having a battery stack formed by stacking a plurality of battery cells and a case member that houses the battery stack, wherein the case member has a floor portion located below the battery stack, an end wall portion located at one end of the battery stack in the stacking direction and connected to the floor portion as one unit, and an attachment shape portion located at the end opposite the end wall portion and for attaching a panel-like member, wherein the battery stack is compressed in the stacking direction while one end of the stacking direction is pressed against the end wall portion, an end panel is attached to the attachment shape portion, and the compression of the battery stack is released to bring the other end of the stacking direction into contact with the end panel, thereby holding the battery stack between the end wall portion and the end panel and being held by the case member, and the end panel is pressed against the attachment shape portion in a direction away from the end wall portion by the compression reaction force of the battery stack and fixed thereto.

[0015] In the battery pack manufacturing method according to the above aspect, the battery stack and the end panel can be fixed together by the compressive reaction force of the battery stack. That is, for example, fastening or welding to fix the end panel is not required. Therefore, the battery pack can be manufactured inexpensively.

[0016] In the battery pack manufacturing method of the above aspect, it is further preferable to use a case member having mounting shapes formed at multiple locations on the end opposite the end wall portion, press the battery stack against the end wall portion by advancing the battery stack from the mounting shapes toward the end wall portion, compress the battery stack until at least a portion of the mounting shapes that was hidden by the battery stack before compression is exposed, and attach an end panel to the mounting shapes exposed by the compression of the battery stack. This allows the position of the end panel to be appropriately adjusted in accordance with individual differences in the length of the battery stack in the stacking direction. No special components or processes are required to adjust the position of the end panel in accordance with individual differences in the length of the battery stack in the stacking direction. Therefore, manufacturing costs are reduced even when there is significant individual difference in the length of the battery stack in the stacking direction.

[0017] In the battery pack manufacturing method of the above aspect, it is further preferable to use a case member in which an alignment portion that aligns the battery cells of the battery stack in the stacking direction is formed in the floor portion, and to use a battery stack that includes a fitting member that fits into the alignment portion along with the plurality of battery cells, and to press the battery stack against the end wall portion while fitting the fitting member into the alignment portion. In this way, a battery pack in which the battery cells are aligned in the stacking direction can be manufactured with an inexpensive configuration using the alignment portion and the fitting member. Furthermore, no special process is required for aligning the battery cells in the stacking direction, thereby reducing the manufacturing cost of the battery pack.

[0018] In the battery pack manufacturing method of the above aspect, the battery stack preferably includes end plates positioned outside the battery cells at both ends in the stacking direction, an end panel having a first anti-detachment portion at its lower portion that prevents a first end plate, which is an adjacent end plate, from moving upward and separating from the case member, and a first hook portion that hooks onto the first anti-detachment portion when the first end plate moves upward from its state housed in the case member. The end panel is preferably attached to the mounting portion by lowering the end panel with the first anti-detachment portion facing downward from above the mounting portion. This prevents the first end plate from moving upward and separating from the case member. In other words, a battery pack can be manufactured in which the battery stack is appropriately prevented from separating from the case member.

[0019] In the battery pack manufacturing method of the above aspect, it is further preferable to use a case member in which an end wall portion is provided with a second separation prevention portion that prevents an adjacent second end plate from moving upward and separating from the case member, and to use a case member in which the second end plate is provided with a second catch portion that catches on the second separation prevention portion when the second end plate moves upward from a state where it is housed in the case member. In this way, both the first end plate and the second end plate are prevented from moving upward and separating from the case member. In other words, it is possible to manufacture a battery pack in which separation of the battery stack from the case member is appropriately prevented.

[0020] In the battery pack manufacturing method of the above aspect, it is further preferable to use a case member in which the second separation prevention portion is located above the first separation prevention portion, and to use a first end plate in which the length of the first hook portion is longer than the length of the second hook portion in the stacking direction of the battery stack. This more reliably prevents both the first end plate and the second end plate from moving upward and separating from the case member. [Effects of the Invention]

[0021] 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]

[0022] [Figure 1] 1 is an external perspective view of a battery pack according to a first embodiment. [Figure 2] FIG. 2 is an exploded perspective view of a battery stack that constitutes a battery pack according to the first embodiment. [Figure 3] FIG. 2 is an exploded perspective view of a battery case that constitutes a battery pack according to the first embodiment. [Figure 4] 2 is a cross-sectional view (cross-section AA shown in FIG. 1) in the stacking direction of the battery pack according to the first embodiment. [Figure 5] 5 is a cross-sectional view in the width direction of the battery pack according to the first embodiment (cross-section BB shown in FIG. 4). [Figure 6] 4A to 4C are diagrams illustrating how the battery stack according to the first embodiment is inserted into a case member. [Figure 7] 4A to 4C are diagrams illustrating a specific example of how the battery stack according to the first embodiment is inserted into a case member. [Figure 8] FIG. 2 is a diagram illustrating a battery stack aligned in a case member according to the first embodiment. [Figure 9] 10A and 10B are diagrams illustrating how an end panel is attached while compressing a battery stack according to the first embodiment. [Figure 10]FIG. 10 is a schematic cross-sectional view of a battery pack according to a second embodiment. [Figure 11] FIG. 10 is a perspective view showing the vicinity of a first end plate and an end panel of a battery pack according to a second embodiment. [Figure 12] 10A and 10B are diagrams illustrating why the battery stack is prevented from coming off the case member when the battery pack according to the second embodiment is vibrated. [Figure 13] 5A to 5C are schematic diagrams illustrating a method for manufacturing a battery pack according to a second embodiment. [Figure 14] 10A to 10C are schematic diagrams illustrating a manufacturing method of a battery pack according to a comparative example of the battery pack according to the second embodiment. [Figure 15] FIG. 10 is a plan view of a battery pack according to a third embodiment. [Figure 16] 10A and 10B are diagrams illustrating modified examples of the structure of the battery stack. DETAILED DESCRIPTION OF THE INVENTION

[0023] Hereinafter, embodiments embodying the present disclosure will be described in detail with reference to the accompanying drawings. First, a first embodiment embodying the present disclosure will be described, and then, the other embodiments will be described with respect to differences from the above-described embodiment.

[0024] (First form) In the first embodiment, the disclosed technology is applied to a battery pack 1, the overall configuration of which is shown in Fig. 1. The battery pack 1 in Fig. 1 has a battery stack 10 housed inside a battery case 20.

[0025] 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.

[0026] 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.

[0027] 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 constitutes the bottom portion 22. The case member 200 also has an end wall portion 220 that constitutes a side wall 23 at one end in the stacking direction of the battery stack 10. The floor portion 210 and the end wall portion 220 are part of the case member 200 and are connected to each other.

[0028] The case member 200 has an opening 225 at an end opposite the end wall portion 220 in the stacking direction of the battery stack 10. An attachment portion 230 is provided at the edge of the opening 225 of the case member 200. An end panel 250 is attached to the attachment portion 230 provided at the opening 225 of the case member 200. Details of the attachment portion 230 will be described later. The opening 225 of the case member 200 is closed by the end panel 250 attached to the attachment portion 230. Note that a cover member or the like that covers the upper part of the battery pack 1 is attached as appropriate depending on the actual usage situation, etc.

[0029] 2 is an exploded perspective view of a battery stack 10. The battery stack 10 includes battery cells 100, spacers 150, and end plates 160. The battery cells 100 of this embodiment are exteriorly made of a conductive metal. Two pole terminals 102 are provided on an upper surface 101 of the battery cells 100. One of the two pole terminals 102 is a positive electrode and the other is a negative electrode.

[0030] The spacer 150 is made of an insulating material. For example, an insulating resin can be used as the material for the spacer 150. Note that a material with high thermal conductivity is preferable for the spacer 150 in order to improve the heat dissipation of the battery cell 100. The spacer 150 has a recess 151 on the side of the battery cell 100. Inside the recess 151, the spacer 150 has inner wall surfaces 152 located on both ends of the battery cell 100 in the width direction. The battery cell 100 and the spacer 150 are assembled by fitting the battery cell 100 into the recess 151 of the spacer 150.

[0031] The inner wall surface 152 of the spacer 150 comes into contact with the battery cell 100 assembled to the spacer 150. This positions the battery cell 100 and the spacer 150 in the width direction. In the battery stack 10, multiple assemblies of battery cells 100 and spacers 150 are arranged in the X direction. This insulates the battery cells 100 from one another in the battery stack 10. Two alignment protrusions 155 are provided below the spacer 150. The two alignment protrusions 155 are arranged with a gap between them in the width direction. Figure 2 shows the battery cell 100 and spacer 150 closest to the end panel 250 in the battery pack 1.

[0032] As shown in FIG. 2 , the end plate 160 is disposed on the end panel 250 side of the battery cell 100 in the battery stack 10 that is closest to the end panel 250. The end plate 160 can be made of the same material as the spacer 150. The end plate 160 is an L-shaped member having a facing portion 161 and a bottom portion 162. The facing portion 161 extends upward from the bottom portion 162 along the outer surface of the opposing battery cell 100. The end plate 160 also has multiple ribs 163 connected to the facing portion 161 and the bottom portion 162. Spaces 164 are formed between the multiple ribs 163 and outside the ribs 163 located at both ends in the width direction.

[0033] 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, the pole terminals 102 can be easily and appropriately connected by the bus bar 30.

[0034] FIG. 3 is an exploded perspective view of the battery case 20. FIG. 3 shows an enlarged view of the vicinity of the mounting portion 230 of the case member 200, together with the end panel 250. Three grooves are formed in the mounting portion 230 of the case member 200 along the edge of the opening 225. These three grooves are spaced apart in the stacking direction of the battery stack 10. These three grooves, in order from closest to the opening 225, are a first mounting shape portion 231, a second mounting shape portion 232, and a third mounting shape portion 233. The widths of the first mounting shape portion 231, the second mounting shape portion 232, and the third mounting shape portion 233 in the stacking direction are large enough to allow the end panel 250 to be inserted.

[0035] The end panel 250 is a flat member. The end panel 250 is attached to the attachment portion 230 by being inserted from above into one of the first attachment shape portion 231, the second attachment shape portion 232, and the third attachment shape portion 233. In FIG. 3, hatched areas indicate the portions of the end panel 250 that are pressed against the attachment portion 230. For example, to prevent water from entering the battery pack 1, elastic seal members can be provided at the hatched areas of the end panel 250. This can improve the waterproofness of the battery pack 1.

[0036] Two alignment grooves 240 extending in the stacking direction of the battery stack 10 are formed on the upper surface of the floor portion 210 of the case member 200. The alignment grooves 240 extend from the opening 225 side to the end wall portion 220. The width and spacing of the two alignment grooves 240 correspond to the sizes of the two alignment protrusions 155 of the spacer 150.

[0037] 4 is a cross-sectional view of the battery pack 1 in the stacking direction of the battery cells 100 (cross-section AA shown in FIG. 1). As shown in FIG. 4, an end plate 160 is arranged at the end of the battery stack 10 on the end panel 250 side in the stacking direction. In addition, an end plate 170 is arranged at the end of the battery stack 10 on the end wall portion 220 side in the stacking direction. The end plate 170 in this embodiment is positioned relative to adjacent battery cells 100 and has a protrusion similar to the alignment protrusion 155 of the spacer 150.

[0038] In the battery pack 1 shown in Fig. 4, the end panel 250 is attached to the third mounting shape portion 233 of the attachment portion 230. The battery stack 10 in the battery pack 1 is compressed in the stacking direction. That is, the length of the battery stack 10 in the stacking direction when attached to the battery pack 1 is shorter than the length in the uncompressed state before attachment to the battery pack 1. Therefore, the end plates 160, 170 located at both ends of the battery stack 10 press the end wall portion 220 and the end panel 250 in directions away from each other due to the compression reaction force of the compressed battery stack 10.

[0039] The end panel 250 is pressed against the third mounting portion 233 to which it is attached in a direction away from the end wall portion 220. Specifically, the end panel 250 is pressed against the inner wall of the groove-shaped third mounting portion 233, the inner wall farther from the end wall portion 220. This pressing force due to the compression reaction force of the battery stack 10 generates a strong frictional force between the end panel 250 and the third mounting portion 233. This frictional force prevents the end panel 250 from moving in an upward direction away from the third mounting portion 233. Therefore, the end panel 250 is fixed to the third mounting portion 233. In this embodiment, the case member 200 and the end panel 250 receive the compression reaction force of the battery stack 10. Therefore, the case member 200 and the end panel 250 may be made of a material that can appropriately compress the battery stack 10 while withstanding the compression reaction force.

[0040] In the battery pack 1 of this embodiment, no special fastening or joining is required to secure the end panel 250. This reduces the manufacturing cost of the battery pack 1. Furthermore, as described above, if a seal member is provided at the location of the end panel 250 that comes into contact with the third mounting shape portion 233, the compressive reaction force of the battery stack 10 will enhance the watertightness at that location. In other words, the waterproofness of the battery pack 1 can be improved without joining the end panel 250 and the case member 200, for example.

[0041] FIG. 5 is a cross-sectional view of the battery pack 1 in the width direction of the battery cell 100 (cross-section BB shown in FIG. 4). As shown in FIG. 5, two alignment protrusions 155 provided on the lower side of the spacer 150 are fitted into two alignment grooves 240 provided on the upper surface of the floor portion 210 of the case member 200. As a result, the positions of the multiple spacers 150 in the battery stack 10 relative to the case member 200 are constant in the width direction of the battery cells 100. Furthermore, the positions of the multiple battery cells 100 assembled to the spacer 150 relative to the case member 200 in the width direction are also constant. Therefore, in the battery stack 10 of the battery pack 1, the pole terminals 102 of the multiple battery cells 100 are aligned in the stacking direction. Therefore, the alignment grooves 240 provided in the floor portion 210 function as alignment shapes that align the battery cells 100 of the battery stack 10 in the stacking direction. Furthermore, the spacer 150 having the alignment protrusion 155 functions as a fitting member that fits into the alignment groove 240 .

[0042] Next, a description will be given of a method for manufacturing the battery pack 1 of this embodiment. In this embodiment, the battery pack 1 is manufactured by first inserting the battery stack 10 into the case member 200, and then assembling the end panel 250.

[0043] 6 is a diagram showing how the battery stack 10 is inserted into the case member 200. The battery stack 10 is constructed by stacking a plurality of assemblies of battery cells 100 and spacers 150 before being inserted into the case member 200. In this embodiment, an end plate 160 is stacked on the end of the battery stack 10 that faces the end panel 250 in the stacking direction. Then, as shown in FIG. 6, the battery stack 10 is inserted into the case member 200 from the end plate 170 on the opposite side to the end plate 160.

[0044] The battery stack 10 can be inserted into the case member 200 by, for example, holding the battery stack 10 with a chuck device that clamps the battery stack 10 in the width direction or the up-down direction, and moving at least one of the battery stack 10 or the case member 200. Note that the case member 200 may be provided with a recess as needed to avoid interference with the chuck device that holds the battery stack 10.

[0045] FIG. 7 shows a specific example of a spacer 150 for inserting a battery stack 10 into a case member 200 while sandwiching it in the width direction. The spacer 150A shown in FIG. 7 has protrusions 156 that protrude outward on both ends in the width direction. When using the spacer 150A, the battery stack 10 can be held by chuck claws 300 as shown in FIG. 7. The chuck claws 300 support the lower sides of the protrusions 156 and sandwich the battery stack 10 in the width direction below the protrusions 156. Therefore, the battery stack 10 can be inserted into the case member 200 with the battery cells 100 of the battery stack 10 aligned in the stacking direction in advance on the equipment side equipped with the chuck claws 300.

[0046] The battery stack 10 is inserted into the accommodation space 21 of the case member 200 through the opening 225 of the case member 200 while aligning the lower surface of the battery stack 10 along the floor portion 210. The battery stack 10 is inserted into the case member 200 until the end plate 170 abuts against the end wall portion 220, for example.

[0047] An alignment protrusion 155 provided on the spacer 150 protrudes below the battery stack 10. Therefore, when the battery stack 10 is inserted into the case member 200, the alignment protrusion 155 fits into the alignment groove 240. Furthermore, when the battery stack 10 subsequently moves to the back of the accommodation space 21 of the case member 200, the alignment protrusion 155 moves while being guided by the alignment groove 240.

[0048] Fig. 8 is a plan view of the battery stack 10 inserted into the case member 200. As shown in Fig. 8, in the battery stack 10 inserted into the case member 200 while the alignment protrusions 155 are guided by the alignment grooves 240, the positions of the battery cells 100 in the width direction are constant. In other words, the multiple battery cells 100 are aligned in the stacking direction. Therefore, the pole terminals 102 of the multiple battery cells 100 are also aligned in the stacking direction.

[0049] As shown in Fig. 8, the battery stack 10 in an uncompressed state that is simply inserted into the case member 200 overlaps and hides at least one of the first mounting shape portion 231, the second mounting shape portion 232, and the third mounting shape portion 233. The battery stack 10 shown in Fig. 8 hides the third mounting shape portion 233.

[0050] FIG. 9 is a diagram illustrating the assembly of the end panel 250. The assembly of the end panel 250 is performed while compressing the battery stack 10 in the stacking direction. In this embodiment, the battery stack 10 is compressed using a pressing device having a pressing part 400 that presses the end plate 160. The tip 401 of the pressing part 400 has a shape (e.g., a comb shape) that allows it to be inserted into the space 164 while avoiding interference with the multiple ribs 163. Such a pressing part 400 is pressed against the end plate 160 as shown in FIG.

[0051] That is, the pressing unit 400 advances the battery stack 10 from the mounting unit 230 side toward the end wall portion 220. As a result, the battery stack 10 is compressed in the stacking direction while the end plate 170 on the opposite side to the side receiving the pressure is pressed against the end wall portion 220. In this embodiment, the pressing unit 400 compresses the battery stack 10 with a predetermined constant pressure. During this compression, the battery cells 100 in the battery stack 10 move toward the end wall portion 220. However, because the alignment protrusions 155 of the spacer 150 and the alignment grooves 240 of the case member 200 fit together, the alignment of the battery cells 100 is not disrupted.

[0052] Here, there are individual differences in the length in the stacking direction among the constituent members such as the battery cells 100 and spacers 150 that make up the battery stack 10. When multiple battery cells 100 and spacers 150 with individual differences are stacked, the individual differences in the length in the stacking direction in the battery stack 10 tend to become large.

[0053] For this reason, the position of the pressing unit 400 when the battery stack 10 is compressed with a constant pressure may differ for each battery stack 10. Therefore, in this embodiment, the position of the pressing unit 400 compressing the battery stack 10 in the stacking direction is detected by the detection unit 310. The detection unit 310 has a first detection unit 311, a second detection unit 312, and a third detection unit 313. The first detection unit 311, the second detection unit 312, and the third detection unit 313 are arranged in order from farthest from the end wall portion 220.

[0054] The first detection unit 311 detects the pressing unit 400 when the position of the end of the end plate 160 of the battery stack 10 being compressed (contact surface 165 in contact with the end panel 250) is closer to the end wall portion 220 than the right inner wall surface 231a of the first mounting shape portion 231 and closer to the opening 225 than the right inner wall surface 232a of the second mounting shape portion 232. The second detection unit 312 detects the pressing unit 400 when the position of the end of the end plate 160 of the battery stack 10 being compressed is closer to the end wall portion 220 than the right inner wall surface 232a of the second mounting shape portion 232 and closer to the opening 225 than the right inner wall surface 233a of the third mounting shape portion 233. The third detection unit 313 detects the pressing unit 400 when the end position of the end plate 160 of the compressed battery stack 10 is closer to the end wall portion 220 than the right inner wall surface 233a of the third mounting shape portion 233.

[0055] Then, depending on the detection state of the detection unit 310, the end panel 250 is assembled by inserting it from above into the mounting portion 230. Specifically, when the first detection unit 311 is in the detecting state, the end panel 250 is assembled to the first mounting shape portion 231. When the second detection unit 312 is in the detecting state, the end panel 250 is assembled to the second mounting shape portion 232. When the third detection unit 313 is in the detecting state, the end panel 250 is assembled to the third mounting shape portion 233. In other words, the end panel 250 is assembled at a position where the gap between the end plate 160 and the end panel 250 in the compressed battery stack 10 is smallest. In FIG. 9 , the third detection unit 313 of the detection unit 310 is in the detecting state, so the end panel 250 is assembled to the third mounting shape portion 233.

[0056] Thereafter, the pressing portion 400 is pulled upward to release the compression of the battery stack 10 by the pressing portion 400. When the compression is released, the battery stack 10, which had been compressed in the stacking direction, expands. The difference in the overall length of the battery stack 10 in the stacking direction between the compressed and uncompressed states according to this embodiment is greater than the pitch between the first mounting shape portion 231, the second mounting shape portion 232, and the third mounting shape portion 233. This pitch is the distance between the left inner wall surfaces 231b, 232b, and 233b of the first mounting shape portion 231, the second mounting shape portion 232, and the third mounting shape portion 233. Furthermore, the length of the battery stack 10 with the shortest overall length is longer than the distance from the end wall portion 220 to the left inner wall surface 233b of the third mounting shape portion 233 in the uncompressed state. Therefore, the battery stack 10 is inserted between the end wall portion 220, which has a length shorter than the overall length in the uncompressed state, and the end panel 250.

[0057] In this way, at least a portion of the first mounting shape portion 231, the second mounting shape portion 232, and the third mounting shape portion 233, where the end panel 250 is ultimately attached, is hidden by the battery stack 10 before the battery stack 10 is compressed in the stacking direction. The battery stack 10 is kept in a compressed state until the first mounting shape portion 231, the second mounting shape portion 232, and the third mounting shape portion 233, where the end panel 250 is ultimately attached, is exposed. Thereafter, the end panel 250 is attached, and the pressing portion 400 is removed, thereby releasing the compression of the battery stack 10. Thus, the end plate 160 of the decompressed battery stack 10 comes into contact with the end panel 250. This completes the manufacture of the battery pack 1. After that, the bus bar 30 and other procedures are appropriately attached to the battery stack 10 of the battery pack 1.

[0058] After the battery stack 10 is released from the compressed state and stretches to contact the end panel 250, it remains in a more contracted state than in the uncompressed state. Therefore, the battery stack 10 in the battery pack 1 is sandwiched between the end wall portion 220 and the end panel 250. This holds the battery stack 10 in the accommodation space 21 of the battery case 20. Furthermore, the end panel 250 in the battery pack 1 is pressed against the third mounting shape portion 233 (specifically, the left inner wall surface 233b in FIG. 8 ) in a direction away from the end wall portion 220 by the compression reaction force of the battery stack 10. This prevents the end panel 250 from falling off the third mounting shape portion 233. Therefore, the battery stack 10 and the end panel 250 are appropriately prevented from falling off the case member 200. That is, no special fastening or joining is required to secure the battery stack 10 and the end panel 250.

[0059] Furthermore, in the battery pack 1, three grooves are provided in the case member 200 as locations for attaching the end panel 250: a first mounting shape portion 231, a second mounting shape portion 232, and a third mounting shape portion 233. The end panel 250 is attached to one of the first mounting shape portion 231, the second mounting shape portion 232, and the third mounting shape portion 233 at a location that can adequately withstand the compressive reaction force of the battery stack 10. Attaching the end panel 250 does not require complicated position adjustments according to individual differences in the battery stack 10 or a complex mechanism for such position adjustments. Therefore, the battery pack 1 can be manufactured inexpensively even when battery stacks 10 with large individual differences are used.

[0060] Furthermore, the multiple battery cells 100 in the battery stack 10 are aligned in the stacking direction by fitting the alignment protrusions 155 of the spacers 150 into the alignment grooves 240 of the case member 200. The alignment of the battery cells 100 occurs when the battery stack 10 is inserted into the case member 200 before the end panel 250 is attached. The end panel 250 is then attached while the battery stack 10 is compressed with the battery cells 100 aligned. Even if the battery stack 10 moves due to this compression, disruption of the alignment is suppressed. Furthermore, even in the battery stack 10 in a compressed state after the end panel 250 is attached, movement of the aligned battery cells 100 is suppressed. In other words, the multiple battery cells 100 are appropriately aligned despite the simple configuration. No special process is required to align this battery stack 10. In addition, because the battery cells 100 are aligned, subsequent attachment of the bus bar 30 is less likely to result in poor joining or fastening, and the bus bar 30 can be attached accurately. Therefore, the battery pack 1 with aligned battery cells 100 can be manufactured inexpensively.

[0061] As described above in detail, this embodiment uses a case member 200 that includes a floor portion 210, an end wall portion 220, and an attachment portion 230. The floor portion 210 is a portion located below the battery stack 10. The end wall portion 220 is located at one end of the battery stack 10 in the stacking direction and is an integral portion connected to the floor portion 210. The attachment portion 230 is located at the end opposite the end wall portion 220 and has a third attachment shape portion 233 for attaching a panel-shaped end panel 250. The battery stack 10 is then compressed in the stacking direction, with one end of the stacking direction pressed against the end wall portion 220. Next, the end panel 250 is attached to the third attachment shape portion 233. Next, the compression of the battery stack 10 is released, and the other end of the stacking direction is brought into contact with the end panel 250. As a result, the battery stack 10 is sandwiched between the end wall portion 220 and the end panel 250 and held by the case member 200. Furthermore, the end panel 250 is pressed against the third mounting shape portion 233 in a direction away from the end wall portion 220 by the compressive reaction force of the battery stack 10 and fixed thereto. The battery pack 1 manufactured in this manner does not have any components that require length adjustment in accordance with variations in the length of the battery stack 10 in the stacking direction. This realizes a battery pack 1 and a manufacturing method thereof that can reduce manufacturing costs.

[0062] (Second form) Next, a second embodiment will be described. This embodiment has a detachment prevention structure that can more reliably prevent the battery stack housed in the case member from detaching from the case member. Therefore, this embodiment uses a battery pack that is partly different from that of the first embodiment. In the description of this embodiment, components that are different from those of the first embodiment will be described using different reference numerals from those of the first embodiment. Components that are similar to those of the first embodiment will be described using the same reference numerals as those of the first embodiment.

[0063] 10 is a schematic cross-sectional view of the battery pack 2 of this embodiment. The battery pack 2 includes a battery stack 11, a case member 600, and an end panel 650.

[0064] The battery stack 11 has end plates 560, 570 at both ends in the stacking direction of the battery cells 100. In this embodiment, the end plate on the end panel 650 side is referred to as the first end plate 560, and the end plate on the end wall portion 620 side of the case member 600 is referred to as the second end plate 570. That is, in the battery pack 2, the first end plate 560 and the end panel 650 are provided adjacent to each other. Also, in the battery pack, the second end plate 570 and the end wall portion 620 are provided adjacent to each other.

[0065] In the battery stack 11 of this embodiment, multiple battery cells 100 are stacked in the X direction between a first end plate 560 and a second end plate 570. The battery cells 100 are appropriately attached to spacers 150. In this respect, this embodiment is similar to the first embodiment. Note that in Figure 10 and subsequent figures, details of the battery cells 100 and spacers 150 may be omitted.

[0066] The first end plate 560 is disposed closest to the end panel 650 in the battery stack 11. That is, the first end plate 560 is positioned outward of the battery cell 100 located at the end of the battery stack 11 closest to the end panel 650 in the stacking direction of the battery cells 100 in the battery stack 11. The first end plate 560 is provided with a first catch portion 561 that protrudes toward the end panel 650. The first catch portion 561 is provided at a lower portion on the end panel 650 side. FIG. 10 shows the length L1 of the first catch portion 561 of the first end plate 560.

[0067] End panel 650 is provided with a first separation prevention portion 651 that restricts upward movement of adjacent first end plates 560. First separation prevention portion 651 is provided on the lower part of end panel 650. First separation prevention portion 651 is located above first catch portion 561 of first end plate 560. Therefore, when first end plate 560 moves upward, upper surface 561A of first catch portion 561 of first end plate 560 catches on lower surface 651A of first separation prevention portion 651. This prevents first end plate 560 from moving upward and separating from case member 600.

[0068] The second end plate 570 is disposed closest to the end wall portion 620 in the battery stack 11. That is, the second end plate 570 is positioned outward of the battery cell 100 positioned closest to the end wall portion 620 in the stacking direction of the battery cells 100 in the battery stack 11. The second end plate 570 is provided with a second hook portion 571 that protrudes toward the end wall portion 620. FIG. 10 shows the length L2 of the second hook portion 571 of the second end plate 570. In this embodiment, the length L1 of the first hook portion 561 of the first end plate 560 is longer than the length L2 of the second hook portion 571 of the second end plate 570.

[0069] The end wall portion 620 is provided with a second separation prevention portion 621 that restricts upward movement of the adjacent second end plate 570. The second separation prevention portion 621 of the end wall portion 620 is a recessed portion shaped to correspond to the second catch portion 571 of the second end plate 570. The second catch portion 571 of the second end plate 570 is inserted inside the second separation prevention portion 621 of the end wall portion 620. The second separation prevention portion 621 is provided on the upper portion of the end wall portion 620. When the second end plate 570 moves upward, an upper surface 571A of the second catch portion 571 of the second end plate 570 catches on the upper inner wall 621A of the second separation prevention portion 621, which is a recessed portion. This prevents the second end plate 570 from moving upward and separating from the case member 600. The second catch portion 571 of the second end plate 570 and the second separation prevention portion 621 of the end wall portion 620 are located above the first catch portion 561 of the first end plate 560 and the first separation prevention portion 651 of the end panel 650.

[0070] 11 is a perspective view showing the vicinity of the first end plate 560 and end panel 650 of the battery pack 2. As shown in FIG. 11, two first catch portions 561 are provided on the lower part of the first end plate 560. The two first catch portions 561 are provided spaced apart in the width direction of the battery cell 100. The first end plate 560 has a pressed portion 562 on its surface facing the end panel 650. The pressed portion 562 is a portion that receives pressure from the tip surface 411 of the pressing portion 410 when, for example, compressing the battery stack 11 in the stacking direction of the battery cells 100.

[0071] Moreover, the first end plate 560 of this embodiment is composed of a base portion 560A and a pressed plate 560B. The pressed plate 560B is located closer to the end panel 650 than the base portion 560A. The pressed portion 562 is provided on the pressed plate 560B. The pressed plate 560B is held to the base portion 560A by a plate holding portion 563 provided on the base portion 560A. The plate holding portion 563 of this embodiment is a snap fit. The base portion 560A can be made of a material such as an insulating resin. The pressed plate 560B has a higher strength than the base portion 560A. The pressed plate 560B can be made of a material such as a metal.

[0072] The end panel 650 is attached to the mounting portion 230 of the case member 600 by being inserted from above. This is the same as in the first embodiment. The end panel 650 is provided with two first separation prevention portions 651. The two first separation prevention portions 651 are provided in positions corresponding to the two first hook portions 561 of the first end plate 560. Note that, like the first hook portions 561 and first separation prevention portions 651, the second hook portions 571 and second separation prevention portions 621 of this embodiment are also provided in pairs, spaced apart in the width direction of the battery cell 100.

[0073] Furthermore, end panel 650 of this embodiment has an upper surface portion 652 at its upper part. Upper surface portion 652 is a portion that receives downward pressure when end panel 650 is attached to attachment portion 230. End panel 650 has a recess 653. Recess 653 is provided in a position corresponding to pressed portion 562 of first end plate 560. Recess 653 has a notch shape that is formed from the lower end of end panel 650 to the upper side. Therefore, end panel 650 can be attached to attachment portion 230 while first end plate 560 is pressed by pressing portion 410.

[0074] In this embodiment, an air passage 660 is provided on the upper surface of the floor portion 610 of the case member 600. The air passage 660 is a groove-like passage formed between the two alignment groove portions 240 in the width direction of the battery cell 100. The air passage 660 extends from the end panel 650 side to the end wall portion 620. In the battery pack 2, air flows through the air passage 660, which prevents the temperature of the battery cell 100 from rising.

[0075] In this embodiment, first separation prevention portion 651 of end panel 650 has a notch shape formed from the lower end of end panel 650 to the upper side. First catch portion 561 is provided above ventilation passage 660. Therefore, first catch portion 561 is prevented from obstructing the flow of air in ventilation passage 660.

[0076] In the battery pack 2 of this embodiment, a separation prevention structure is provided by the first catch portion 561, the second catch portion 571, the first separation prevention portion 651, and the second separation prevention portion 621, thereby preventing the battery stack 11 from separating from the case member 600. This will be described below.

[0077] For example, when the battery pack 2 is mounted on an electric vehicle, it may vibrate in response to vibrations of the body of the electric vehicle. The battery stack 11 of the vibrated battery pack 2 may deform so that the center in the stacking direction of the battery cells 100 is further away from the floor portion 610 of the case member 600, as shown in Fig. 12. This is because the battery stack 11 is housed in the case member 600 by being sandwiched between the end wall portion 620 and the end panel 650.

[0078] When the battery stack 11 deforms so as to move away from the floor portion 610 of the case member 600 toward the center in the stacking direction of the battery cells 100, a gap is formed between the first end plate 560 and the end panel 650. Alternatively, even if the deformation of the battery stack 11 due to vibration is not so great as to form a gap between the first end plate 560 and the end panel 650, the pressure (surface pressure) with which the first end plate 560 and the end panel 650 press against each other decreases. When a gap is formed between the first end plate 560 and the end panel 650, or when the pressure with which they press against each other decreases, the frictional force between the first end plate 560 and the end panel 650 decreases. When the frictional force between the first end plate 560 and the end panel 650 decreases, the first end plate 560 may move upward relative to the end panel 650.

[0079] Furthermore, if the battery stack 11 deforms so as to move away from the floor portion 610 of the case member 600 toward the center in the stacking direction of the battery cells 100, the second end plate 570 may also move upward relative to the end wall portion 620. Then, as the first end plate 560 and the second end plate 570 move upward, there is a risk that the battery stack 11 may become detached from the case member 600.

[0080] In this embodiment, the above-described problem is solved by providing the first catch portion 561, the second catch portion 571, the first separation prevention portion 651, and the second separation prevention portion 621. That is, when the first end plate 560 moves upward relative to the end panel 650, the first catch portion 561 of the first end plate 560 catches on the first separation prevention portion 651 of the end panel 650, as shown in FIG. 12 . This prevents the first end plate 560 from moving upward relative to the end panel 650.

[0081] 12 , when the second end plate 570 moves upward relative to the end wall portion 620, the second catch portion 571 of the second end plate 570 catches on the second separation prevention portion 621 of the end wall portion 620. This prevents the second end plate 570 from moving upward relative to the end wall portion 620. Therefore, in this embodiment, the battery stack 11 is prevented from being separated from the case member 600.

[0082] Furthermore, when a gap is formed between the second end plate 570 and the end wall portion 620 due to deformation of the battery stack 11 caused by vibration, the gap tends to become larger the further downwards. The second catch portion 571 and the second separation prevention portion 621 are provided on the upper portions of the second end plate 570 and the end wall portion 620, respectively. In other words, the second catch portion 571 and the second separation prevention portion 621 are provided at positions where the gap formed between the second end plate 570 and the end wall portion 620 is small. Therefore, the length of the second catch portion 571 and the second separation prevention portion 621 can be short in the stacking direction of the battery cells 100.

[0083] On the other hand, it is preferable to provide the first separation prevention portion 651 in the lower part of the end panel 650. As described above, the end panel 650 is assembled by lowering it from above the case member 600. For this reason, a passage is required below the first separation prevention portion 651 to allow the first catch portion 561 to pass through when assembling the end panel 650. Furthermore, the higher the first separation prevention portion 651 is provided, the more the strength and rigidity of the end panel 650 will be reduced. Therefore, in this embodiment, the first separation prevention portion 651 is provided in the lower part of the end panel 650.

[0084] Furthermore, since the first separation prevention portion 651 is provided at the bottom of the end panel 650, the first catch portion 561 is also provided at the bottom of the first end plate 560. The bottom portions of the end panel 650 and the first end plate 560 are locations where, if a gap forms between the first end plate 560 and the end panel 650 due to deformation of the battery stack 11 caused by vibration, the gap is more likely to become larger than at the top. Therefore, the length L1 of the first catch portion 561 located at the bottom in the stacking direction of the battery cells 100 is made longer than the length L2 of the second catch portion 571. This ensures that the first catch portion 561 is reliably caught by the first separation prevention portion 651, even if a gap forms between the first end plate 560 and the end panel 650.

[0085] In this embodiment, the first separation prevention portion 651 has a notch shape formed from the lower end of the end panel 650 to the upper side. In other words, the first separation prevention portion 651 is located slightly above the lower end of the end panel 650. This allows the first catch portion 561 to be located as far upward as possible.

[0086] Fig. 13 is a schematic diagram showing a manufacturing method of the battery pack 2. When manufacturing the battery pack 2, as shown in Fig. 13(A), the battery stack 11 is inserted into the inside of the case member 600 while aligning the lower surface thereof with the floor portion 610. Note that Fig. 13(A) shows the battery stack 11 in an uncompressed state.

[0087] Next, as shown in FIG. 13(B), the end panel 650 is assembled to the mounting portion 230 of the case member 600 while compressing the battery stack 11 in the stacking direction of the battery cells 100. The battery stack 11 is compressed by pressing the first end plate 560 toward the end wall portion 620 with the pressing portion 410. The end panel 650 can be assembled by pressing the upper surface portion 652 from above. As with the first embodiment, the assembly position of the end panel 650 can be determined according to the length of the battery stack 11 in the compressed state.

[0088] Thereafter, as shown in FIG. 13(C), the compression of the battery stack 11 is released, so that the battery stack 11 is sandwiched between the end wall portion 620 and the end panel 650. This causes the battery stack 11 to be held in the case member 600. The end panel 650 is fixed in place by the compression reaction force of the battery stack 11. Then, as shown in FIG. 13, in this embodiment, the battery pack 2 can be manufactured using the same procedure as in the first embodiment.

[0089] 13 also shows distances S1 and S2 related to the overall length of the battery stack 11 that change in the stacking direction of the battery cells 100 when manufacturing the battery pack 2. Distance S1 is a compression distance that indicates the difference between the overall length of the battery stack 11 in an uncompressed state and the overall length of the battery stack 11 in a compressed state. Distance S2 is a compression release distance that indicates the difference between the overall length of the battery stack 11 in a compressed state and the overall length of the battery stack 11 after it has been released from compression and housed in the case member 600. That is, the overall length of the battery stack 11 is shortened from the uncompressed state by the compression distance S1 during the manufacturing process due to compression, and then extends from the compressed state by the compression release distance S2 due to the release of compression.

[0090] FIG. 14 shows a comparative battery pack 9 for comparison with the battery pack 2 of the present embodiment. The battery pack 9 has a configuration as described in, for example, Japanese Patent Application Laid-Open No. 2020-95895. The battery pack 9 is similar to the battery pack 2 of the present embodiment in that the battery pack 9 is designed to prevent the battery stack 911 from being separated from the case member 900. The battery pack 9 is also similar to the battery pack 2 of the present embodiment in that the battery pack 9 is manufactured by storing the battery stack 911 in a compressed state in the case member 900 and then releasing the compression to hold the battery stack 911 in the case member 900.

[0091] Specifically, the battery stack 911 of the battery pack 9 is formed by stacking multiple battery cells 912 in the left-right direction in Fig. 14. As shown in Fig. 14(A), the battery stack 911 has a first end plate 960 at one end in the stacking direction of the battery cells 912 and a second end plate 970 at the other end. Both the first end plate 960 and the second end plate 970 have an inclined shape that widens outward in the stacking direction of the battery cells 912 as they approach the lower portions.

[0092] The case member 900 has a floor portion 910 located below the battery stack 911, and a first end wall portion 921 and a second end wall portion 922 provided at both ends of the floor portion 910 in the stacking direction of the battery cells 912. Both the first end wall portion 921 and the second end wall portion 922 have an inclined shape that widens outward in the stacking direction of the battery cells 912 as they approach the lower portions. In addition, the distance between the top of the first end wall portion 921 and the top of the second end wall portion 922 in the stacking direction of the battery cells 912 is shorter than the overall length of the battery stack 911 in an uncompressed state shown in FIG. 14(A).

[0093] The battery pack 9 is manufactured by changing the battery stack 911 from the uncompressed state shown in FIG. 14(A) to the compressed state shown in FIG. 14(B) and then housing it inside the case member 900. In the stacking direction of the battery cells 912, the overall length of the battery stack 911 in the compressed state is shorter than the distance between the upper parts of the first end wall portion 921 and the second end wall portion 922. The compressed battery stack 911 is then passed between the first end wall portion 921 and the second end wall portion 922 and inserted into the case member 900. Thereafter, as shown in FIG. 14(C), the compression of the battery stack 911 is released, and the battery stack 911 is housed inside the case member 900. In the stacking direction of the battery cells 912, the length of the lower part of the battery stack 911 is longer than the distance between the upper parts of the first end wall portion 921 and the second end wall portion 922. Therefore, in the battery pack 9, the battery stack 911 is prevented from coming off the case member 900.

[0094] 14 also shows distances T1, T2, and T3 related to the overall length of the battery stack 911 that change in the stacking direction of the battery cells 912 during the manufacture of the battery pack 9. Distance T1 is a compression distance that indicates the difference between the overall length of the battery stack 911 in an uncompressed state and the overall length of the battery stack 911 in a compressed state. Distance T2 is the distance that the first end wall portion 921 moves from the compressed state until the first end plate 960 comes into contact with the first end wall portion 921 after the compression is released. Distance T3 is the distance that the second end wall portion 922 moves from the compressed state until the second end plate 970 comes into contact with the second end wall portion 922 after the compression is released. Therefore, the sum of distances T2 and T3 is the compression release distance that indicates the difference between the overall length of the battery stack 911 in a compressed state and the overall length of the battery stack 911 after the compression is released and the battery stack 911 is housed in the case member 900. That is, during the manufacturing process, the total length of the battery stack 911 is compressed by a compression distance T1 from the uncompressed state, and then, when the compression is released, it expands from the compressed state by the combined distance of distances T2 and T3.

[0095] When comparing the change in overall length during the manufacturing process between the battery pack 2 according to the present embodiment and the battery pack 9 according to the comparative example, the battery pack 2 according to the present embodiment has a smaller change. That is, the compressed distance S1 of the battery pack 2 according to the present embodiment is shorter than the compressed distance T1 of the battery pack 9 according to the comparative example. Furthermore, the uncompressed distance S2 of the battery pack 2 according to the present embodiment is shorter than the combined distance of the uncompressed distances T2 and T3 according to the comparative example.

[0096] Therefore, the configuration of the battery pack 2 according to this embodiment can accommodate a variety of battery stacks compared to the configuration of the battery pack 9 according to the comparative example. Specifically, the configuration of the battery pack 9 according to the comparative example can only accommodate a battery stack 911 whose overall length can be significantly reduced. That is, for example, if battery cells 912 that are difficult to deform in the stacking direction are used, there is a possibility that the battery stack 911 cannot be housed in the case member 900. In contrast, the configuration of the battery pack 2 according to this embodiment can also accommodate a battery stack 11 whose overall length cannot be significantly reduced.

[0097] Furthermore, in the battery pack 9 according to the comparative example, the more one tries to reliably prevent the battery stack 911 from coming off the case member 900, the narrower the gap between the upper part of the first end wall portion 921 and the upper part of the second end wall portion 922. In other words, in the battery pack 9 according to the comparative example, unless a battery stack 911 whose overall length can be significantly reduced is employed, it may not be possible to reliably prevent the battery stack 911 from coming off the case member 900.

[0098] On the other hand, in the battery pack 2 according to this embodiment, the length L1 of the first hooking portion 561 and the length L2 of the second hooking portion 571 need to be increased to reliably prevent the battery stack 11 from being separated from the case member 600. In particular, the first hooking portion 561 and the first separation prevention portion 651 are provided at the lower portions of the first end plate 560 and the end panel 650. Therefore, as described above, the length L1 of the first hooking portion 561 needs to be increased to some extent. However, in the configuration of the battery pack 2 according to this embodiment, even if the length L1 of the first hooking portion 561 and the length L2 of the second hooking portion 571 are increased, the amount of change in the overall length of the battery stack 11 when the battery stack 11 is accommodated in the case member 600 does not change. In other words, even when a battery stack 11 whose overall length cannot be significantly reduced is used, the length L1 of the first hooking portion 561 can be sufficiently ensured.

[0099] As described above in detail, according to this embodiment, the battery stack 11 of the battery pack 2 includes a first end plate 560 and a second end plate 570. The first end plate 560 and the second end plate 570 are located outside the battery cells 100 located at both ends in the stacking direction of the battery cells 100. A first separation prevention portion 651 is provided at the bottom of the end panel 650 to prevent the adjacent first end plate 560 from moving upward and separating from the case member 600. The first end plate 560 is also provided with a first catch portion 561 that catches on the first separation prevention portion 651 when the first end plate 560 moves upward. In manufacturing the battery pack 2, the end panel 650 is attached to the mounting portion 230 by lowering the end panel 650, with the first separation prevention portion 651 facing downward, from above the mounting portion 230. In the battery pack 2 manufactured in this manner, the first end plate 560 is prevented from moving upward and separating from the case member 600. This allows for a reduction in manufacturing costs, and realizes a battery pack 2 in which separation of the battery stack 11 from the case member 600 is appropriately suppressed, and a manufacturing method thereof.

[0100] Furthermore, according to the present embodiment, the end wall portion 620 is provided with a second separation prevention portion 621 that prevents the adjacent second end plate 570 from moving upward and separating from the case member 600. The second separation prevention portion 621 is located higher than the first separation prevention portion 651. The second end plate 570 is also provided with a second catch portion 571 that catches on the second separation prevention portion 621 when the second end plate 570 moves upward. The length L1 of the first catch portion 561 is longer than the length L2 of the second catch portion 571 in the stacking direction of the battery cells 100 in the battery stack 11. This prevents the second end plate 570 from moving upward and separating from the case member 600 in the battery pack 2. Therefore, a battery pack 2 in which the battery stack 11 is more reliably prevented from separating from the case member 600 and a manufacturing method thereof are realized.

[0101] (Third Form) Next, a third embodiment will be described. Like the second embodiment, this embodiment is also configured to appropriately prevent the battery stack housed in the case member from separating from the case member. However, in this embodiment, a separation prevention structure is provided on the end plates at both ends in the stacking direction of the battery cells that are most susceptible to vibration, depending on the overall configuration of the battery pack. In this embodiment, some parts of the battery pack are different from those in the previously described embodiments. In the description of this embodiment, parts that differ from those in the previously described embodiments will be described using different reference numerals. Parts that are similar to those in the previously described embodiments will be described using the same reference numerals.

[0102] 15 is a plan view of the battery pack 3 of this embodiment. The battery pack 3 has a battery stack 12, a case member 700, an end panel 655, and an on-board device 800.

[0103] The battery stack 12 has a first end plate 565 at the end on the end panel 655 side in the stacking direction of the battery cells 100. The battery stack 12 also has a second end plate 570 at the end on the end wall portion 720 side of the case member 700 in the stacking direction of the battery cells 100. Unlike the second embodiment, the first end plate 565 does not have a catch portion. The first end plate 565 is the same as the second embodiment except that it does not have a catch portion. The second end plate 570 is the same as that described in the second embodiment. That is, the second end plate 570 is provided with a second catch portion 571.

[0104] The case member 700 has a configuration similar to that of the second embodiment with respect to the area that houses the battery stack 12. That is, the end wall portion 720 is provided with a second detachment prevention portion 621 that can prevent the second end plate 570 from moving upward and detaching from the case member 700 by being caught by the second catch portion 571 of the second end plate 570. In addition, an end panel 655 is attached to the attachment portion 230 of the case member 700. Unlike the second embodiment, the end panel 655 does not have a detachment prevention portion. The end panel 655 is the same as that of the second embodiment except that it does not have a detachment prevention portion.

[0105] The case member 700 has a mounting area 701 in addition to the components of the second embodiment. The mounting area 701 is provided on the opposite side of the end wall portion 720 from the battery stack 12 side. The mounting area 701 mounts mounted devices 800. The mounted devices 800 include, for example, a control unit that controls charging and discharging of the battery stack 12, acquires information related to the battery stack 12, and outputs the information to external devices. The mounted devices 800 are lighter than the battery stack 12. In the battery pack 3, the weight of the battery stack 12 accounts for a large proportion of the total weight.

[0106] The case member 700 further has a first mounting portion 730, a second mounting portion 740, a third mounting portion 750, and a fourth mounting portion 760. The case member 700 of this embodiment is placed on and fixed to the first base portion 830, the second base portion 840, the third base portion 850, and the fourth base portion 860. The first base portion 830, the second base portion 840, the third base portion 850, and the fourth base portion 860 are all components external to the battery pack 3. The first mounting portion 730, the second mounting portion 740, the third mounting portion 750, and the fourth mounting portion 760 are portions that come into contact with the tops of the first base portion 830, the second base portion 840, the third base portion 850, and the fourth base portion 860, respectively.

[0107] The first mounting portion 730, the second mounting portion 740, the third mounting portion 750, and the fourth mounting portion 760 each have fixed portions 731, 741, 751, and 761 with through holes formed therein. The first base portion 830, the second base portion 840, the third base portion 850, and the fourth base portion 860 each have fixing portions 831, 841, 851, and 861 with screw holes formed at positions corresponding to the fixed portions 731, 741, 751, and 761. The fixed portions 731, 741, 751, and 761 are fixed to the fixing portions 831, 841, 851, and 861, respectively, by fastening with bolts 810.

[0108] The first installation portion 730 and the second installation portion 740 are provided on one outer edge of the battery cell 100 in the width direction. The fixed portion 731 of the first installation portion 730 and the fixed portion 741 of the second installation portion 740 are provided at different positions in the stacking direction of the battery cells 100. The third installation portion 750 and the fourth installation portion 760 are provided on the outer edge of the battery cell 100 on the opposite side in the width direction from the first installation portion 730 and the second installation portion 740. The fixed portion 751 of the third installation portion 750 and the fixed portion 761 of the fourth installation portion 760 are provided at different positions in the stacking direction of the battery cells 100.

[0109] The fixed portion 731 of the first installation portion 730 and the fixed portion 741 of the second installation portion 740 are provided near the heavy battery stack 12. On the other hand, the fixed portion 751 of the third installation portion 750 and the fixed portion 761 of the fourth installation portion 760 are provided at a location farther from the battery stack 12. Furthermore, when the fixed portion 751 of the third installation portion 750 is compared with the fixed portion 761 of the fourth installation portion 760, the fixed portion 761 of the fourth installation portion 760 is provided at a location farther from the battery stack 12. The third installation portion 750 is connected from the fixed portion 751 to the vicinity of the battery stack 12. The fourth installation portion 760 is connected from the fixed portion 761 to the vicinity of the battery stack 12. Therefore, when the first mounting portion 730, the second mounting portion 740, the third mounting portion 750, and the fourth mounting portion 760 are fixed by the respective fixed portions 731, 741, 751, and 761, they can appropriately support the heavy battery stack 12.

[0110] The fixed portion 751 of the third installation portion 750 and the fixed portion 761 of the fourth installation portion 760 are respectively located at both ends of the fixed portions 731, 741, 751, and 761 in the stacking direction of the battery cells 100. Fig. 15 shows an intermediate position C1 between the fixed portion 751 of the third installation portion 750 and the fixed portion 761 of the fourth installation portion 760, which are located at both ends in the stacking direction of the battery cells 100. The intermediate position C1 is a position where the distance from the fixed portion 751 of the third installation portion 750 and the distance from the fixed portion 761 of the fourth installation portion 760 in the stacking direction of the battery cells 100 are both distance D1.

[0111] In the battery pack 3, the center of gravity and the arrangement of the fixing points may not be well balanced due to various factors. In the battery pack 3, the mounted device 800 is mounted, which causes a bias in the arrangement of the battery stack 12 in the battery pack 3. As shown in Fig. 15 , in the battery pack 3, the battery stack 12 is located on the fixed part 751 side of the third mounting part 750, and the mounted device 800 is located on the fixed part 761 side of the fourth mounting part 760.

[0112] 15 shows the position C2 of the center of gravity of the battery stack 12 in the stacking direction of the battery cells 100, and the position C3 of the center of gravity of the battery pack 3 in the stacking direction of the battery cells 100. The position C3 of the center of gravity of the battery pack 3 is located closer to the position C2 of the center of gravity of the heavier battery stack 12 than to the intermediate position C1 between the fixed portion 751 of the third installing portion 750 and the fixed portion 761 of the fourth installing portion 760. In other words, the fixed portion 751 of the third installing portion 750 is the eccentric fixed portion that is closer to the position C3 of the center of gravity of the battery pack 3 than to the intermediate position C1, of the fixed portion 751 of the third installing portion 750 and the fixed portion 761 of the fourth installing portion 760 that are located at both ends.

[0113] 15 also shows a distance D2 between the end panel 655 and the fixed portion 751 of the third mounting portion 750 in the stacking direction of the battery cells 100. Distance D2 is the distance between the end panel 655 and the fixed portion 751 of the third mounting portion 750 or the fixed portion 761 of the fourth mounting portion 760, whichever is closer to the end panel 655, and the end panel 655. FIG. 15 also shows a distance D3 between the end wall portion 720 and the fixed portion 761 of the fourth mounting portion 760 in the stacking direction of the battery cells 100. Distance D3 is the distance between the end wall portion 720 and the fixed portion 751 of the third mounting portion 750 or the fixed portion 761 of the fourth mounting portion 760, whichever is closer to the end wall portion 720, and the end wall portion 720.

[0114] In such a battery pack 3 configuration, when vibration occurs in the battery pack 3, of the first end plate 565 and the second end plate 570, it is the second end plate 570 that is most likely to move in a direction that causes it to separate from the case member 700 due to the influence of the vibration. This is because, in the battery pack 3, the acceleration caused by the vibration is more likely to be greater at the position of the second end plate 570 than at the position of the first end plate 565. Therefore, in this embodiment, a separation prevention structure is provided for the second end plate 570, which is more likely to move due to the influence of the vibration of the battery pack 3. That is, a second separation prevention portion 621 is provided on the end wall portion 720 adjacent to the second end plate 570, and a second catch portion 571 is provided on the second end plate 570.

[0115] As described above in detail, according to this embodiment, the battery stack 12 of the battery pack 3 has a first end plate 565 and a second end plate 570. The first end plate 565 and the second end plate 570 are located outside the battery cells 100 located at both ends in the stacking direction of the battery cells 100. The case member 700 has fixed portions 751 and 761 fixed to external fixing portions 851 and 861. The fixed portions 751 and 761 are located at both ends in the stacking direction of the battery cells 100. The center of gravity position C3 of the battery pack 3 is located closer to the fixed portion 751, which is the eccentric fixed portion, than the intermediate position C1 between the fixed portions 751 and 761 in the stacking direction of the battery cells 100. The end wall portion 720 is provided with a second separation prevention portion 621 that prevents the adjacent second end plate 570 from moving upward and separating from the case member 700. The second end plate 570 is also provided with a second catch portion 571 that catches on the second separation prevention portion 621 when it moves upward. The end wall portion 720 is the end wall portion 720 or the end panel 655 that is farthest from the fixed portion 751 in the stacking direction of the battery cells 100. In other words, when the battery pack 3 vibrates, the second end plate 570 adjacent to the end wall portion 720 is easily affected by the vibration and moves. In the battery pack 3, the second end plate 570, which is easily affected by the vibration, can be prevented from separating from the case member 700. Therefore, this embodiment reduces manufacturing costs and realizes a battery pack 3 in which separation of the battery stack 12 from the case member 700 is appropriately prevented.

[0116] The above-described embodiments and examples are merely illustrative and do not limit the present disclosure. Therefore, the present disclosure can be improved and modified in various ways without departing from the spirit and scope of the present disclosure. For example, in the first embodiment described above, the mounting portion for mounting the end panel is configured to include three groove-shaped portions: a first mounting portion 231, a second mounting portion 232, and a third mounting portion 233. However, the number and shapes of the mounting portions can be changed as appropriate.

[0117] In the first embodiment, the mounting portion for mounting the end panel 250 is described as being located at a position where the gap between the end panel 250 and the end plate 160 of the battery stack 10 in a compressed state is smallest. However, the position of the mounting portion for mounting the end panel 250 may be any position that allows the battery stack 10 in the battery pack 1 to be compressed to a desired degree. That is, the relationship between the position of the mounting portion for mounting the end panel 250 and the length of the battery stack 10 in the stacking direction in a compressed state can be determined in advance. Then, in manufacturing the battery pack 1, a detection value indicating the length of the battery stack 10 in the stacking direction in a compressed state is detected, and the position of the mounting portion for assembling the end panel 250 is determined based on the detection value. That is, the mounting portion for assembling the end panel 250 may be at least partially hidden when the battery stack 10 is in an uncompressed state and exposed when the battery stack 10 is in a compressed state.

[0118] In the first embodiment described above, the spacer 150 of the battery stack 10 is provided with the alignment protrusion 155, and the floor portion 210 of the case member 200 is provided with the alignment groove 240. However, for example, a configuration in which a groove is provided on the spacer 150 side and a protrusion is provided on the floor portion 210 side is also possible. Furthermore, the portion of the battery stack 10 that fits into the shape of the floor portion 210 may be provided somewhere other than the spacer 150, as long as it is positioned with respect to the battery cells 100 in the width direction. In other words, the floor portion 210 of the case member 200 is formed with an alignment shape portion that aligns the battery cells 100 of the battery stack 10, and the battery stack 10 includes a fitting member that fits into the alignment shape portion along with the plurality of battery cells 100.

[0119] In the first embodiment described above, the battery cells 100 in the battery stack 10 are aligned on the equipment side before being inserted into the case member 200. However, the alignment of the battery cells 100 in the battery stack 10 before being inserted into the case member 200 may be performed by a configuration on the battery stack 10 itself. FIG. 10 shows a specific example in which a configuration that allows the alignment of the battery cells 100 is added to the battery stack 10. FIG. 10 is a cross-sectional view of a battery stack 10 having a spacer 150B according to a modified example. Note that FIG. 10 is a cross-sectional view of the battery stack 10 cut horizontally. The spacer 150B shown in FIG. 10 has a positioning portion 157 in addition to the shape of the spacer 150. The positioning portion 157 extends to the adjacent spacer 150B in the battery stack 10. The adjacent spacer 150B fits into the positioning portion 157. This allows the spacer 150B to align the battery cell 100 assembled in the recess 151 with the adjacent spacer 150B in the width direction. This allows the adjacent battery cells 100 to be aligned in the stacking direction. Note that the spacer can also be designed so that both adjacent battery cells 100 can be fitted into it.

[0120] In the second and third embodiments, the end wall of the case member is provided with a recess as a separation prevention portion, and the second end plate is provided with a protrusion as a hook portion. However, the end wall may be provided with a protrusion as a separation prevention portion, and the second end plate may be provided with a recess as a hook portion.

[0121] In the third embodiment, the battery pack is described in which the second endplate is more susceptible to vibration than the other endplates in the stacking direction of the battery cells. However, if the first endplate is more susceptible to vibration, i.e., if the arrangement of the end wall portion and the end panel is the opposite of that shown in Figure 15, it is preferable to provide a separation prevention structure for the first endplate.

[0122] Furthermore, the application of the above embodiment is not particularly limited with respect to the type of battery (nickel-metal hydride battery, lithium-ion battery, etc.). [Explanation of symbols]

[0123] 1, 2, 3 Battery Pack 10, 11, 12 Battery stack 100 battery cells 150 Spacer (fitting part) 155 Alignment convex part 200, 600, 700 case material 210, 610 floor section 220, 620, 720 End wall section 230 Mounting part 231 First mounting shape portion (mounting shape portion) 232 Second mounting shape portion (mounting shape portion) 233 Third mounting shape part (mounting shape part) 240 Alignment groove section (alignment shape section) 250, 650, 655 End Panel 560 First end plate 570 Second end plate 561 First hook 571 Second hook 621 Second Withdrawal Suppression Unit 651 First Detachment Suppression Unit 751, 761 Fixed part 851, 861 Fixed part

Claims

1. A battery pack including a battery stack in which a plurality of battery cells are stacked, and a case member that houses the battery stack, The case member is a floor portion located below the battery stack; an end wall portion located at one end of the battery stack in the stacking direction and integral with the floor portion; The end wall portion is located at an end opposite to the end wall portion, and has a mounting shape portion for mounting a panel-shaped member, an end panel attached to the mounting profile; the battery stack is sandwiched between the end wall portion and the end panel and held by the case member, the end panel is pressed against the mounting portion in a direction away from the end wall portion by a compressive reaction force of the battery stack and fixed thereto; the case member has the mounting shape portions formed at a plurality of locations on an end portion opposite to the end wall portion, The end panel is attached to one of the attachment portions at a plurality of locations on the battery pack.

2. 2. The battery pack according to claim 1, an alignment shape portion that aligns the battery cells of the battery stack in a stacking direction is formed on the floor portion; The battery pack includes a fitting member that fits into the alignment portion in the battery stack, along with the plurality of battery cells.

3. 3. The battery pack according to claim 1 or 2, the battery stack has end plates located outward from battery cells located at both ends in the stacking direction, a first separation prevention portion is provided at a lower portion of the end panel to prevent a first end plate, which is an adjacent end plate, from moving upward and separating from the case member; The battery pack has a first catch portion provided on the first end plate that catches on the first separation prevention portion when the first end plate moves upward.

4. A battery pack according to claim 3, a second separation prevention portion is provided on the end wall portion to prevent the second end plate, which is the adjacent end plate, from moving upward and separating from the case member; The battery pack is provided with a second catch portion on the second end plate that catches on the second separation prevention portion when the second end plate moves upward.

5. A battery pack according to claim 4, The second separation prevention portion is provided at a position higher than the first separation prevention portion, The battery pack, wherein the length of the first hook portion is longer than the length of the second hook portion in the stacking direction of the battery stack.

6. 3. The battery pack according to claim 1 or 2, the battery stack has end plates located outward from battery cells located at both ends in the stacking direction, the case member has a plurality of fixed portions that are fixed to external fixing portions in a stacking direction of the battery stack, a center of gravity of the battery pack is located closer to the eccentric fixed portion of one of the fixed portions at both ends than to an intermediate position between the fixed portions at both ends of the plurality of fixed portions in a stacking direction of the battery stack, a separation prevention portion that prevents the adjacent end plate from moving upward and separating from the case member is provided on one of the end wall portion and the end panel that is farther from the eccentric-side fixed portion in the stacking direction of the battery stack, The battery pack has a catch portion on the end plate adjacent to the one portion that catches on the separation prevention portion when the end plate moves upward.

7. A method for manufacturing a battery pack having a battery stack in which a plurality of battery cells are stacked, and a case member that houses the battery stack, comprising: The case member includes: a floor portion located below the battery stack; an end wall portion located at one end of the battery stack in the stacking direction and integral with the floor portion; The end wall portion is located at an end opposite the end wall portion, and has a mounting shape portion for mounting a panel-shaped member. pressing one end of the battery stack in the stacking direction against the end wall portion while compressing the battery stack in the stacking direction; Attaching an end panel to the mounting configuration; The compression of the battery stack is released to bring the other end of the stacking direction into contact with the end panel, The battery stack is sandwiched between the end wall portion and the end panel and held by the case member, A method for manufacturing a battery pack, wherein the end panel is pressed against the mounting shape portion in a direction away from the end wall portion and fixed thereto by a compressive reaction force of the battery stack.

8. A method for manufacturing a battery pack according to claim 7, comprising: The case member has the mounting shape portions formed at a plurality of locations on an end portion opposite to the end wall portion, the pressing of the battery stack against the end wall portion is performed by moving the battery stack from the mounting shape portion side toward the end wall portion; compressing the battery stack until at least a portion of the mounting shape portion that was hidden by the battery stack before the battery stack was compressed is exposed among the plurality of mounting shape portions; The end panel is attached to the attachment portion exposed by compressing the battery stack.

9. A method for manufacturing a battery pack according to claim 7 or claim 8, comprising: The case member has an alignment shape portion formed on the floor portion that aligns the battery cells of the battery stack in a stacking direction, the battery stack includes a fitting member that fits into the alignment portion together with the plurality of battery cells; The method for manufacturing a battery pack includes pressing the battery stack against the end wall portion while fitting the fitting member and the alignment portion together.

10. A method for manufacturing a battery pack according to claim 7 or claim 8, comprising: The battery stack has end plates positioned outward from the battery cells positioned at both ends in the stacking direction, The end panel has a first separation prevention portion provided at a lower portion thereof for preventing a first end plate, which is an adjacent end plate, from moving upward and separating from the case member, The first end plate is provided with a first catch portion that catches on the first separation prevention portion when the first end plate moves upward from a state where it is housed in the case member, A method for manufacturing a battery pack in which the end panel is attached to the mounting shape portion by lowering the end panel, with the first removal prevention portion facing downward, from above the mounting shape portion.

11. A method for manufacturing a battery pack according to claim 10, comprising: The case member is provided with a second separation prevention portion in the end wall portion that prevents a second end plate, which is the adjacent end plate, from moving upward and separating from the case member, A method for manufacturing a battery pack using a second end plate that is provided with a second hook portion that hooks onto the second separation prevention portion when moved upward from a state housed in the case member.

12. A method for manufacturing a battery pack according to claim 11, comprising: As the case member, the second separation prevention portion is provided at a position higher than the first separation prevention portion, A method for manufacturing a battery pack, wherein the first end plate has a length of the first hook portion that is longer than a length of the second hook portion in the stacking direction of the battery stack.

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