Battery module and spacer

Abstract

To provide a battery module capable of appropriately cooling a battery cell, and provide a spacer.SOLUTION: In a battery module, a plurality of battery cells 20 and a synthetic resin spacer 13 that is arranged between the battery cells 20 are alternately laminated. The spacer 13 includes: a plurality of bar parts 50 that is arranged with an interval along each battery cell 20; a first fin part 56 that is formed so as to incline relative to an arrangement direction and extend to a side of a first battery cell 20A, and is in contact with the first battery cell 20A; and a second fine part 57 that is formed so as to incline relative to the arrangement direction and extend to the side of a second battery cell 20B, and is in contact with the surface of the second battery cell 20B. Each of a third bar part 53 and a fourth bar part 54 is an end part bar part arranged nearer to an end part of an electrode body 23 than the first bar part 51 and the second bar part 52. A connection position of a fin part 55 provided on the end part bar part and the end part bar part is positioned on an inner side from the end part of the end part bar part in an orthogonal direction.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present invention relates to a battery module and a spacer. [Background technology]

[0002] In the battery module described in Patent Document 1, spacers are placed between the battery cells. The spacers have wall portions sandwiched between the main surfaces of the adjacent battery cells, and notches that penetrate the wall portions in the thickness direction are formed in the wall portions. By using such spacers and passing cooling gas through the notches, the temperature difference between the adjacent battery cells through the spacers is reduced. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2014-82170 Summary of the Invention [Problem to be solved by the invention]

[0004] However, with the technology described in Patent Document 1, there is a risk that the passageway for the cooling gas that penetrates the spacer in the thickness direction may become narrower than expected. That is, the internal pressure of the battery cells in the battery module may increase due to gas generated inside the case, causing them to expand. Part of the expanded battery cell may enter the passageway for the cooling gas provided in the spacer. In other words, if the battery cell expands, the passageway for the cooling gas provided in the spacer may become narrower than when the battery cell does not expand. This may result in inadequate cooling of the battery cell. [Means for solving the problem]

[0005] The battery module that solves the above problem is a battery module in which a plurality of battery cells and spacers made of synthetic resin that are arranged between the battery cells are alternately stacked, and the spacers each include a plurality of bar sections that are arranged at intervals along the battery cells, a first fin section that is provided on the bar sections and extends toward one of the battery cells at an angle with respect to the arrangement direction of the bar sections, and contacts a surface of the one of the battery cells, and a second fin section that is provided on the bar sections and extends toward the other battery cell that is different from the one of the battery cells at an angle with respect to the arrangement direction, and contacts a surface of the other battery cell. and a second fin portion that contacts the surface of the battery cell, the bar portion having an end bar portion, the portion of the electrode body that does not contact the inner wall when the electrode body stored in the battery cell is in an unpressed state where it is not pressed against the inner wall of the battery cell case, the end bar portion is positioned closer to the end of the electrode body than the other bar portions, and only one of the first fin portion and the second fin portion is provided as a fin portion, and the connection position of the end bar portion with the fin portion is located more inward than the end of the end bar portion in a direction perpendicular to the arrangement direction.

[0006] According to the above configuration, the first fin portion contacts the surface of one of the battery cells, thereby ensuring an appropriate distance from the surface of the one battery cell, and the second fin portion contacts the surface of the other battery cell, thereby ensuring an appropriate distance from the surface of the other battery cell. Therefore, the spacer ensures an appropriate distance between adjacent battery cells. Therefore, heat is appropriately dissipated into the space between the battery cells, allowing the battery cells to be appropriately cooled. Furthermore, when the end bar portion is in a non-pressured state, the electrode body housed in the battery cell is positioned closer to the end that is not pressed against the inner wall of the battery cell case. Therefore, the distance between the bar portions can be wider than when the electrode body is positioned in a position where the inner wall of the battery cell case and the electrode body are in contact in a non-pressured state, thereby widening the cooling path. Furthermore, the connection position between the end bar portion and the fin portion is located inside the end of the end bar portion. Therefore, the end bar portion can press the battery cell case without being obstructed by the fin portion, further supporting the electrode body.

[0007] In the battery module, the thickness of the end bar portion preferably corresponds to the distance between the inner wall of the case and the electrode assembly in an unpressurized state. With this configuration, the thickness of the end bar portion corresponds to the distance between the inner wall of the case and the electrode assembly when the spacer is not pressed, so that when the spacer is pressed against the battery cell, the end bar portion further presses the case, further supporting the electrode assembly.

[0008] In the battery module, it is preferable that the first fin portion and the second fin portion are provided on the same bar portion among the plurality of bar portions. According to the above configuration, the first fin portion and the second fin portion are provided on the same bar portion, so that the first fin portion and the second fin portion come into contact with both adjacent battery cells, thereby ensuring insulation.

[0009] In the battery module, it is preferable that the first fin portion is inclined with respect to a first arrangement direction of the arrangement direction, and the second fin portion is inclined with respect to a second arrangement direction opposite to the first arrangement direction.

[0010] According to the above configuration, the first fin portion is inclined with respect to the first arrangement direction, and the second fin portion is inclined with respect to the second arrangement direction, so that the first fin portion and the second fin portion contact adjacent battery cells at different positions, thereby ensuring insulation.

[0011] In the above battery module, it is preferable that the first fin portion is provided on a first bar portion of the plurality of bar portions, and the second fin portion is provided on a second bar portion of the plurality of bar portions that is different from the first bar portion.

[0012] According to the above configuration, the first fin portion is provided on the first bar portion, and the second fin portion is provided on the second bar portion different from the first bar portion. Therefore, the first fin provided on the first bar portion and the second fin provided on the second bar portion contact each of the adjacent battery cells separately, thereby ensuring insulation.

[0013] It is preferable that the above battery module has two first fin portions, one of which is inclined with respect to a first arrangement direction of the arrangement direction and the other of which is inclined with respect to a second arrangement direction opposite to the first arrangement direction, and that the battery module has two second fin portions, one of which is inclined with respect to the first arrangement direction and the other of which is inclined with respect to the second arrangement direction.

[0014] According to the above configuration, the first bar section has first fin sections that are inclined with respect to the first arrangement direction and second fin sections that are inclined with respect to the second arrangement direction, and the second bar section has first fin sections that are inclined with respect to the first arrangement direction and second fin sections that are inclined with respect to the second arrangement direction. As a result, at least two fin sections from each bar section come into contact with the battery cells, thereby ensuring insulation between adjacent battery cells.

[0015] In the above battery module, it is preferable that the first fin portion is inclined with respect to a first arrangement direction of the arrangement direction, the second fin portion is inclined with respect to the first arrangement direction, and the battery module is provided with a first stopper portion formed on the first bar portion and extending in a second arrangement direction opposite to the first arrangement direction, and a second stopper portion formed on the second bar portion and extending in the second arrangement direction.

[0016] According to the above configuration, the first bar section is provided with first fin sections inclined with respect to the first arrangement direction and first stopper sections extending in the second arrangement direction, and the second bar section is provided with first fin sections inclined with respect to the first arrangement direction and second stopper sections extending in the second arrangement direction. As a result, at least the fin sections and stopper sections of each bar section come into contact with the battery cells, thereby ensuring insulation between adjacent battery cells.

[0017] The spacer that solves the above problem is a spacer made of synthetic resin and placed between multiple battery cells that make up a battery module, and includes: multiple bar portions arranged at intervals from each other; first fin portions provided on the bar portions and extending in a first orthogonal direction perpendicular to a first arrangement direction in which the bar portions are arranged, and formed at an angle with respect to a first arrangement direction in which the bar portions are arranged; and second fin portions provided on the bar portions and extending in the first orthogonal direction and at an angle with respect to a second arrangement direction opposite to the first arrangement direction, wherein the bar portions include end bar portions, and when an electrode body housed in the battery cell is not pressed against the inner wall of the battery cell case in an unpressed state, the portion of the electrode body that does not contact the inner wall is the end portion, and the end bar portions are positioned closer to the end portion of the electrode body than the other bar portions, and only one of the first fin portion and the second fin portion is provided as a fin portion, and the connection position of the end bar portion with the fin portion is located more inward than the end of the end bar portion in the orthogonal direction perpendicular to the arrangement direction.

[0018] According to the above configuration, the first fin portion contacts the surface of one of the battery cells, thereby ensuring an appropriate distance from the surface of the one battery cell, and the second fin portion contacts the surface of the other battery cell, thereby ensuring an appropriate distance from the surface of the other battery cell. Therefore, the spacer ensures an appropriate distance between adjacent battery cells. Therefore, heat is appropriately dissipated into the space between the battery cells, allowing the battery cells to be appropriately cooled. Furthermore, when the end bar portion is in a non-pressed state, the electrode body housed in the battery cell is positioned closer to the end that is not pressed against the inner wall of the battery cell case. Therefore, the distance between the bar portions can be wider than when the electrode body housed in the battery cell is located in a position where the inner wall of the battery cell case and the inner wall of the battery cell case are in contact in a non-pressed state, thereby widening the cooling path. Furthermore, the connection position between the end bar portion and the fin portion is located inside the end of the end bar portion. Therefore, the end bar portion can press the battery cell case without being obstructed by the fin portion, further supporting the electrode body.

[0019] In the spacer, the thickness of the end bar portion is preferably a thickness that corresponds to the distance between the inner wall of the case and the electrode body in an unpressed state. With this configuration, the thickness of the end bar portion corresponds to the distance between the inner wall of the case and the electrode assembly when the spacer is not pressed, so that when the spacer is pressed against the battery cell, the end bar portion further presses the case, further supporting the electrode assembly. [Effects of the Invention]

[0020] According to the present invention, the battery cells can be cooled appropriately. [Brief explanation of the drawings]

[0021] [Figure 1] 1 is a perspective view showing a schematic configuration of a battery module according to a first embodiment. [Figure 2] 2 is a cross-sectional view of the battery module of the embodiment taken along line 2-2 of FIG. 1. [Figure 3] FIG. 2 is a perspective view of the spacer of the embodiment. [Figure 4] 4 is a cross-sectional view of a space forming portion of the spacer in an uncompressed state according to the embodiment; FIG. [Figure 5] 4 is a cross-sectional view of a space forming portion of the spacer in a compressed state according to the embodiment. FIG. [Figure 6] FIG. 4 is an enlarged cross-sectional view of a space forming portion of the spacer in a compressed state according to the embodiment. [Figure 7] FIG. 10 is an enlarged cross-sectional view of a space forming portion of a modified spacer in a compressed state. [Figure 8] FIG. 10 is a cross-sectional view of a space forming portion of a spacer in a non-compressed state according to a second embodiment. [Figure 9] 4 is a cross-sectional view of a space forming portion of the spacer in a compressed state according to the embodiment. FIG. [Figure 10] FIG. 11 is a cross-sectional view of a space forming portion of a spacer in a non-compressed state according to a third embodiment. [Figure 11] 4 is a cross-sectional view of a space forming portion of the spacer in a compressed state according to the embodiment. FIG. [Figure 12] FIG. 10 is a cross-sectional view of a space forming portion of a modified spacer in a compressed state. DETAILED DESCRIPTION OF THE INVENTION

[0022] (First embodiment) A first embodiment of a battery module and a spacer will be described below with reference to FIGS.

[0023] (Battery module 10) As shown in FIG. 1 , the battery module 10 has a lower case 11 and multiple battery cells 20 housed within it. The lower case 11 is a box-shaped member with an open top. The battery cells 20 have a flattened rectangular parallelepiped outer shape. The multiple battery cells 20 are stacked and arranged within the lower case 11. Each battery cell 20 has a surface in the X direction, which is the stacking direction of the battery cells 20. Surface 21 of the battery cell 20 is the largest outer surface. The battery module 10 houses two rows of battery groups each made up of multiple stacked battery cells 20. The direction in which the rows of battery groups of battery cells 20 are arranged is the Y direction. The direction toward the top of the lower case 11 is the Z direction. Bus bars, pole terminals, an upper case, etc. are actually attached to the battery module 10, but these are omitted from the illustration.

[0024] As shown in FIG. 2, the lower case 11 has a floor portion 11A and an end wall portion 11B. The floor portion 11A is a portion of the lower case 11 located below the multiple battery cells 20. The end wall portion 11B is a portion of the lower case 11 located to the side of the multiple battery cells 20. The multiple battery cells 20 housed in the lower case 11 are stacked alternately with spacers 13. In other words, the spacers 13 are arranged between the battery cells 20. End plates 14 are sandwiched between the battery cells 20 on both ends and the end wall portions 11B. The spacers 13 and end plates 14 are made of synthetic resin. The spacers 13 and end plates 14 are insulating and have a certain degree of flexibility.

[0025] The battery cells 20, spacers 13, and end plates 14 are constrained by the end wall portions 11B at both ends in the stacking direction (X direction). As a result, the battery cells 20, spacers 13, and end plates 14 are subjected to a compressive load in the stacking direction (X direction). When compressed and housed in the battery module 10, the battery cells 20, spacers 13, and end plates 14 are compressed in the stacking direction (X direction) more than when they are uncompressed.

[0026] (Spacer 13) 3, the spacer 13 has a space-forming portion 13C. The space-forming portion 13C is provided in the center portion of the spacer 13. The space-forming portion 13C is a portion that forms a space between the battery cells 20 located on both sides of the spacer 13.

[0027] The spacer 13 has a plurality of bar portions 50 in the space forming portion 13C. The bar portions 50 extend in the longitudinal direction (Y direction) of the surface 21 of the battery cell 20. The plurality of bar portions 50 are arranged at intervals from one another in the vertical direction (Z direction) along the surface 21 of the battery cell 20. Fin portions 55 are provided on the plurality of bar portions 50. The space forming portion 13C is composed of the bar portions 50 and the fin portions 55.

[0028] (Space forming part 13C) Next, the space forming portion 13C will be described in detail with reference to Figures 4 and 5. Figures 4 and 5 are cross-sectional views of the space forming portion 13C of the spacer 13. Figure 4 shows the space forming portion 13C in an uncompressed state together with the adjacent battery cells 20 on both sides. Figure 5 shows the space forming portion 13C in a compressed state together with the adjacent battery cells 20 on both sides.

[0029] As shown in FIG. 4 , the bar portion 50 includes, from top to bottom, a third bar portion 53, a first bar portion 51, a second bar portion 52, and a fourth bar portion 54. The battery cell 20 houses an electrode body 23 wound in a case 22. The ends of the electrode body 23 in the vertical direction (Z direction) are arc-shaped. Therefore, the distance between the inner wall 22A of the case 22 of the battery cell 20 and the electrode body 23 housed in the battery cell 20 increases as the distance approaches the top and bottom ends in the arrangement direction (Z direction) in which the bar portions 50 are arranged. Therefore, the third bar portion 53 and the fourth bar portion 54 are provided near the ends where the inner wall 22A of the case 22 of the battery cell 20 and the electrode body 23 housed in the battery cell 20 do not come into contact in an unpressured state in the orthogonal direction (X direction) perpendicular to the arrangement direction (Z direction) in which the bar portions 50 are arranged. The non-pressurized state is an uncompressed state in which the electrode body 23 is not pressed against the inner wall 22A of the case 22. The third bar portion 53 and the fourth bar portion 54 correspond to end bar portions. The fin portion 55 has a first fin portion 56 and a second fin portion 57.

[0030] The first bar portion 51 and the second bar portion 52 are provided with a first fin portion 56 and a second fin portion 57. The first fin portion 56 is inclined at a first angle θA with respect to a first arrangement direction (upward direction) in the arrangement direction (Z direction) in which the bar portions 50 are arranged, and extends in a first orthogonal direction (rightward in the figure) perpendicular to the arrangement direction (Z direction). The second fin portion 57 is inclined at a second angle θB with respect to a second arrangement direction (downward direction) opposite to the first arrangement direction, and extends in a second orthogonal direction (leftward in the figure) opposite to the first orthogonal direction. The first fin portion 56 contacts the surface 21 of the first battery cell 20A on the right side in the figure. The second fin portion 57 contacts the surface 21 of the second battery cell 20B on the left side in the figure. The first angle θA and the second angle θB are the same angle.

[0031] A second fin portion 57 is provided on the third bar portion 53. The second fin portion 57 is inclined at a second angle θB with respect to the second arrangement direction (downward) and extends in a second orthogonal direction (leftward in the figure). The second fin portion 57 contacts the surface 21 of the second battery cell 20B on the left side.

[0032] A first fin portion 56 is provided on the fourth bar portion 54. The first fin portion 56 is inclined at a first angle θA with respect to the first arrangement direction (upward) and extends in a first orthogonal direction (rightward in the figure). The first fin portion 56 contacts the surface 21 of the first battery cell 20A on the right side.

[0033] The connection position between the first fin portion 56 provided on the first bar portion 51 and the first bar portion 51 is located at the end of the first bar portion 51 facing the first battery cell 20A in the orthogonal direction (X direction). The connection position between the second fin portion 57 provided on the first bar portion 51 and the first bar portion 51 is located at the end of the first bar portion 51 facing the second battery cell 20B in the orthogonal direction (X direction). The connection position between the first fin portion 56 provided on the second bar portion 52 and the second bar portion 52 is located at the end of the second bar portion 52 facing the first battery cell 20A in the orthogonal direction (X direction). The connection position between the second fin portion 57 provided on the second bar portion 52 and the second bar portion 52 is located at the end of the second bar portion 52 facing the second battery cell 20B in the orthogonal direction (X direction).

[0034] The connection position between the second fin portion 57 provided on the third bar portion 53 and the third bar portion 53 is located more inward in the orthogonal direction (X direction) than the end of the third bar portion 53. Similarly, the connection position between the first fin portion 56 provided on the fourth bar portion 54 and the fourth bar portion 54 is located more inward in the orthogonal direction (X direction) than the end of the fourth bar portion 54.

[0035] (uncompressed state) As shown in FIG. 4, in the uncompressed state, the tip of the first fin portion 56 provided on the first bar portion 51 protrudes toward the first battery cell 20A side on the right side in the drawing rather than the first bar portion 51. In the uncompressed state, the tip of the second fin portion 57 provided on the first bar portion 51 protrudes toward the second battery cell 20B side on the left side in the drawing rather than the first bar portion 51. In the uncompressed state, the tip of the first fin portion 56 provided on the second bar portion 52 protrudes toward the first battery cell 20A side on the right side in the drawing rather than the second bar portion 52. In the uncompressed state, the tip of the second fin portion 57 provided on the second bar portion 52 protrudes toward the second battery cell 20B side on the left side in the drawing rather than the second bar portion 52. The tip of the second fin portion 57 provided on the third bar portion 53 protrudes toward the second battery cell 20B side on the left side rather than the third bar portion 53. The tip of the first fin portion 56 provided on the fourth bar portion 54 protrudes toward the first battery cell 20A side on the right side rather than the fourth bar portion 54. The first bar portion 51, the second bar portion 52, the third bar portion 53, and the fourth bar portion 54 do not contact either the surface 21 of the first battery cell 20A on the right side or the surface 21 of the second battery cell 20B on the left side.

[0036] The first fin length LA, which is the length of the first fin portion 56 from the first bar portion 51, and the second fin length LB, which is the length of the second fin portion 57 from the third bar portion 53, are both shorter than the distance P between the first bar portion 51 and the third bar portion 53 (LA < P, LB < P). The first fin length LA and the second fin length LB are the same length (LA = LB). The sum of the first fin length LA and the second fin length LB is longer than the distance P between the first bar portion 51 and the third bar portion 53 (LA + LB > P).

[0037] The second fin length LB, which is the length of the second fin portion 57 from the first bar portion 51, and the first fin length LA, which is the length of the first fin portion 56 from the second bar portion 52, are both shorter than the distance P between the first bar portion 51 and the second bar portion 52 (LB < P, LA < P). The second fin length LB and the first fin length LA are the same length (LB = LA). The sum of the second fin length LB and the first fin length LA is longer than the distance P between the first bar portion 51 and the second bar portion 52 (LB + LA > P).

[0038] The second fin length LB, which is the length of the second fin portion 57 from the second bar portion 52, and the first fin length LA, which is the length of the first fin portion 56 from the fourth bar portion 54, are both shorter than the interval P between the second bar portion 52 and the fourth bar portion 54 (LB < P, LA < P). The second fin length LB and the first fin length LA are of the same length (LB = LA). The sum of the second fin length LB and the first fin length LA is longer than the interval P between the second bar portion 52 and the fourth bar portion 54 (LB + LA > P).

[0039] The sum of the projection lengths LZA and LZB in the arrangement direction (Z direction) of the first fin portion 56 and the second fin portion 57 is shorter than the interval P between the first bar portion 51 and the third bar portion 53 in the non-compressed state (LZA + LZB < P). For this reason, in the non-compressed state, a gap G is provided in the arrangement direction (Z direction) between the tips of the first fin portion 56 and the second fin portion 57. Thereby, the first fin portion 56 and the second fin portion 57 are prevented from overlapping in the arrangement direction (Z direction). Such a spacer 13 can be manufactured at a low cost.

[0040] The sum of the projection lengths LZB and LZA in the arrangement direction (Z direction) of the second fin portion 57 and the first fin portion 56 is shorter than the interval P between the first bar portion 51 and the second bar portion 52 in the non-compressed state (LZB + LZA < P). For this reason, in the non-compressed state, a gap G is provided in the arrangement direction (Z direction) between the tips of the second fin portion 57 and the first fin portion 56. Thereby, the second fin portion 57 and the first fin portion 56 are prevented from overlapping in the arrangement direction (Z direction). Such a spacer 13 can be manufactured at a low cost.

[0041] The sum of the projected length LZB in the arrangement direction (Z direction) of the second fin portion 57 and the projected length LZA in the arrangement direction (Z direction) of the first fin portion 56 is shorter than the distance P between the second bar portion 52 and the fourth bar portion 54 in the non-compressed state (LZB + LZA < P). Therefore, in the non-compressed state, a gap G is provided in the arrangement direction (Z direction) between the tips of the second fin portion 57 and the first fin portion 56. As a result, the second fin portion 57 and the first fin portion 56 are prevented from overlapping in the arrangement direction (Z direction). Such a spacer 13 can be manufactured at a low cost.

[0042] (Compressed state) As shown in FIG. 5, in the compressed state, the right side surface of the bar portion 50 is in contact with the surface 21 of the first battery cell 20A on the right side. The surface 21 of the second battery cell 20B on the left side is in contact with the left side surface of the bar portion 50. That is, in the compressed state, the bar portion 50 is sandwiched between the surface 21 of the first battery cell 20A and the surface 21 of the second battery cell 20B, and is compressed in the stacking direction (X direction). Further, the bar portion 50 presses the surface 21 of the first battery cell 20A and the surface 21 of the second battery cell 20B away from each other by the reaction force against the compression. As a result, the contact between the adjacent battery cells 20 is suppressed by the bar portion 50. And a space 15 is formed between the two bar portions 50 adjacent to each other vertically, in which the surfaces 21 of the battery cells 20 adjacent to both sides of the spacer 13 are separated from each other.

[0043] Since the surface 21 of the first battery cell 20A on the right side is in contact with the right side surface of the first bar portion 51, the first fin portion 56 provided on the first bar portion 51 is pressed to the left by the surface 21 of the first battery cell 20A on the right side. By this pressing, the first fin portion 56 is in a state of being bent to the left more than in the non-compressed state along the surface 21 of the first battery cell 20A on the right side. The bent first fin portion 56 extends upward along the surface 21 of the first battery cell 20A on the right side. And the bent first fin portion 56 presses the surface 21 of the first battery cell 20A on the right side to the right by the reaction force of the bending.

[0044] Because the surface 21 of the second left battery cell 20B is in contact with the left side surface of the first bar portion 51, the second fin portion 57 provided on the first bar portion 51 is pressed to the right by the surface 21 of the second left battery cell 20B. Due to this pressing, the second fin portion 57 is bent more to the right than in the uncompressed state along the surface 21 of the second left battery cell 20B. In this bent state, the second fin portion 57 extends downward along the surface 21 of the second left battery cell 20B. In this bent state, the second fin portion 57 presses the surface 21 of the second left battery cell 20B to the left due to the reaction force of the bending.

[0045] Because the surface 21 of the first right battery cell 20A is in contact with the right side surface of the second bar portion 52, the first fin portion 56 provided on the second bar portion 52 is pressed to the left by the surface 21 of the first right battery cell 20A. Due to this pressing, the first fin portion 56 is bent more to the left than in the uncompressed state along the surface 21 of the first right battery cell 20A. In this bent state, the first fin portion 56 extends upward along the surface 21 of the first right battery cell 20A. In this bent state, the first fin portion 56 presses the surface 21 of the first right battery cell 20A to the right due to the reaction force of the bending.

[0046] Because the surface 21 of the second left battery cell 20B is in contact with the left side surface of the second bar portion 52, the second fin portion 57 provided on the second bar portion 52 is pressed to the right by the surface 21 of the second left battery cell 20B. Due to this pressing, the second fin portion 57 is bent more to the right than in the uncompressed state along the surface 21 of the second left battery cell 20B. In this bent state, the second fin portion 57 extends downward along the surface 21 of the second left battery cell 20B. In this bent state, the second fin portion 57 presses the surface 21 of the second left battery cell 20B to the left due to the reaction force of the bending.

[0047] Because the surface 21 of the second left battery cell 20B is in contact with the left side surface of the third bar portion 53, the second fin portion 57 provided on the third bar portion 53 is pressed to the right by the surface 21 of the second left battery cell 20B. Due to this pressing, the second fin portion 57 is bent more to the right than in the uncompressed state along the surface 21 of the second left battery cell 20B. In this bent state, the second fin portion 57 extends downward along the surface 21 of the second left battery cell 20B. In this bent state, the second fin portion 57 presses the surface 21 of the second left battery cell 20B to the left due to the reaction force of the bending.

[0048] Because the surface 21 of the first right battery cell 20A is in contact with the right side surface of the fourth bar portion 54, the first fin portion 56 provided on the fourth bar portion 54 is pressed to the left by the surface 21 of the first right battery cell 20A. Due to this pressing, the first fin portion 56 is bent more to the left than in the uncompressed state along the surface 21 of the first right battery cell 20A. In this bent state, the first fin portion 56 extends upward along the surface 21 of the first right battery cell 20A. In this bent state, the first fin portion 56 presses the surface 21 of the first right battery cell 20A to the right due to the reaction force of the bending.

[0049] As described above, the first fin length LA of the first fin portion 56 and the second fin length LB of the second fin portion 57 are both shorter than the distance P between the first bar portion 51 and the third bar portion 53. Therefore, there is a portion of the surface 21 of the first right-side battery cell 20A that is not covered by the first fin portion 56 within the distance P between the first bar portion 51 and the third bar portion 53. Similarly, there is a portion of the surface 21 of the second left-side battery cell 20B that is not covered by the second fin portion 57 within the distance P between the first bar portion 51 and the third bar portion 53.

[0050] Similarly, the second fin length LB of the second fin portion 57 and the first fin length LA of the first fin portion 56 are both shorter than the distance P between the first bar portion 51 and the second bar portion 52. Therefore, there is a portion of the surface 21 of the first right-side battery cell 20A that is not covered by the second fin portion 57 within the distance P between the first bar portion 51 and the second bar portion 52. Similarly, there is a portion of the surface 21 of the second left-side battery cell 20B that is not covered by the second fin portion 57 within the distance P between the first bar portion 51 and the second bar portion 52.

[0051] Similarly, the second fin length LB of the second fin portion 57 and the first fin length LA of the first fin portion 56 are both shorter than the distance P between the second bar portion 52 and the fourth bar portion 54. Therefore, there is a portion of the surface 21 of the second left battery cell 20B that is not covered by the second fin portion 57 within the distance P between the second bar portion 52 and the fourth bar portion 54. Also, there is a portion of the surface 21 of the first right battery cell 20A that is not covered by the first fin portion 56 within the distance P between the second bar portion 52 and the fourth bar portion 54.

[0052] Therefore, the surfaces 21 of the battery cells 20 on both sides of the spacer 13 have portions exposed to the space 15 at the interval P between the bar portions 50. In other words, when the battery cells 20 on both sides of the spacer 13 generate heat, they can dissipate the heat into the space 15. The space 15 is a passageway for cooling gas in the battery module 10, through which gas for cooling the battery cells 20 flows. As a result, the spacer 13 can cool the battery cells 20 on both sides while preventing the temperature difference between the adjacent battery cells 20 from becoming too large.

[0053] As described above, the sum of the first fin length LA of the first fin portion 56 and the second fin length LB of the second fin portion 57 is longer than the distance P between the first bar portion 51 and the third bar portion 53. Therefore, in the compressed state, the first fin portion 56 and the second fin portion 57 overlap in the arrangement direction (Z direction). That is, there is an overlap L between the tip of the first fin portion 56 and the tip of the second fin portion 57. Therefore, the first fin portion 56 presses at least a region of the first right battery cell 20A that faces a region of the second left battery cell 20B that is not pressed by the second fin portion 57. The second fin portion 57 presses at least a region of the second left battery cell 20B that faces a region of the first right battery cell 20A that is not pressed by the first fin portion 56. In other words, there is no gap between the battery cells 20 on either side of the spacer 13 in the arrangement direction (Z direction) at the distance P between the first bar portion 51 and the third bar portion 53, and the battery cells 20 on either side of the spacer 13 are pressed away from each other by at least one of the first fin portion 56 and the second fin portion 57. Furthermore, the battery cells 20 on either side of the spacer 13 do not come into contact with each other between the first bar portion 51 and the third bar portion 53. For example, even if the adjacent battery cells 20 expand and enter the space 15 while bending their respective first fin portions 56 and second fin portions 57, at least one of the first fin portion 56 and the second fin portion 57 will always be present between the adjacent battery cells 20 on either side. This allows the spacer 13 to reliably maintain insulation between the adjacent battery cells 20 on either side.

[0054] Similarly, the sum of the second fin length LB of the second fin portion 57 and the first fin length LA of the first fin portion 56 is longer than the distance P between the first bar portion 51 and the second bar portion 52. Therefore, in the compressed state, the second fin portion 57 and the first fin portion 56 overlap in the arrangement direction (Z direction). That is, there is an overlap L between the tip of the second fin portion 57 and the tip of the first fin portion 56. Therefore, the second fin portion 57 presses at least a region of the second left battery cell 20B that faces a region of the first right battery cell 20A that is not pressed by the first fin portion 56. The first fin portion 56 presses at least a region of the first right battery cell 20A that faces a region of the first right battery cell 20A that is not pressed by the second fin portion 57. In other words, the battery cells 20 on either side of the spacer 13 have no gap in the arrangement direction (Z direction) at the distance P between the first bar portion 51 and the second bar portion 52, and are pressed away from each other by at least one of the second fin portion 57 and the first fin portion 56. Furthermore, the battery cells 20 on either side of the spacer 13 do not come into contact with each other between the first bar portion 51 and the second bar portion 52. For example, even if the adjacent battery cells 20 expand and enter the space 15 while bending their respective second fin portions 57 and first fin portions 56, at least one of the second fin portion 57 and the first fin portion 56 will always be present between the adjacent battery cells 20. This allows the spacer 13 to reliably maintain insulation between the adjacent battery cells 20 on either side.

[0055] Similarly, the sum of the second fin length LB of the second fin portion 57 and the first fin length LA of the first fin portion 56 is longer than the distance P between the second bar portion 52 and the fourth bar portion 54. Therefore, in the compressed state, the second fin portion 57 and the first fin portion 56 overlap in the arrangement direction (Z direction). That is, there is an overlap L between the tip of the second fin portion 57 and the tip of the first fin portion 56. Therefore, the first fin portion 56 presses at least a region of the right-side first battery cell 20A that faces a region of the left-side second battery cell 20B that is not pressed by the second fin portion 57. The second fin portion 57 presses at least a region of the left-side second battery cell 20B that faces a region of the right-side first battery cell 20A that is not pressed by the first fin portion 56. In other words, the battery cells 20 on either side of the spacer 13 have no gap in the arrangement direction (Z direction) at the distance P between the second bar portion 52 and the fourth bar portion 54, and are pressed away from each other by at least one of the first fin portion 56 and the second fin portion 57. Furthermore, the battery cells 20 on either side of the spacer 13 do not come into contact with each other between the second bar portion 52 and the fourth bar portion 54. For example, even if the adjacent battery cells 20 expand and enter the space 15 while bending their respective second fin portions 57 and first fin portions 56, at least one of the second fin portion 57 and the first fin portion 56 will always be present between the adjacent battery cells 20. This allows the spacer 13 to reliably maintain insulation between the adjacent battery cells 20 on either side.

[0056] As shown in FIG. 6 , the fourth bar portion 54 is provided closer to the end of the electrode assembly 23 in the arrangement direction (Z direction) of the bar portions 50. The fourth bar portion 54 is closer to the end of the electrode assembly 23 than the portion of contact between the inner wall 22A of the case 22 and the electrode assembly 23, indicated by the dashed line. The thickness of the fourth bar portion 54 corresponds to the distance between the inner wall 22A of the case 22 and the electrode assembly 23 in the non-pressed state. That is, because the fourth bar portion 54 is located closer to the end of the electrode assembly 23, the thickness of the fourth bar portion 54 is greater than the thickness of the first bar portion 51 and the thickness of the second bar portion 52. Therefore, when the fourth bar portion 54 is in the compressed state, it pushes the case 22 and contacts the electrode assembly 23, thereby holding the electrode assembly 23. The third bar portion 53 is similar to the fourth bar portion 54.

[0057] 7, the thickness of the fourth bar portion 54 may be increased if the fourth bar portion 54 is positioned closer to the end of the electrode assembly 23 in the arrangement direction (Z direction). In this way, the amount by which the fourth bar portion 54 is pressed into the case 22 increases in a compressed state according to the position of the fourth bar portion 54 in the arrangement direction (Z direction), thereby enabling the electrode assembly 23 to be held. The third bar portion 53 is similar to the fourth bar portion 54.

[0058] Even if the battery cell 20 expands for some reason, the spacer 13 can prevent the battery cell 20 from entering the space 15 by the first fin portion 56 and the second fin portion 57 pressing against the battery cell 20. In other words, even if the battery cell 20 expands, the spacer 13 can prevent the length of the space 15 in the stacking direction (X direction) from becoming narrower, thereby ensuring an appropriate space 15. Therefore, the spacer 13 can prevent the flow rate of the cooling gas flowing through the space 15 from decreasing due to the expansion of the battery cell 20. Therefore, the spacer 13 can prevent a decrease in the cooling function of the cooling gas flowing through the space 15 for the battery cell 20. Furthermore, even if the battery cell 20 expands for some reason, the third bar portion 53 and the fourth bar portion 54 can press the case 22 of the battery cell 20, thereby holding the electrode body 23.

[0059] Next, the effects of the first embodiment will be described. (1-1) The first fin portion 56 and the fourth fin portion 59 contact the surface 21 of the first battery cell 20A, thereby ensuring an appropriate distance from the surface 21 of the first battery cell 20A, and the second fin portion 57 and the third fin portion 58 contact the surface 21 of the second battery cell 20B, thereby ensuring an appropriate distance from the surface 21 of the second battery cell 20B. Therefore, the spacer 13 can ensure an appropriate distance between adjacent battery cells 20. As a result, heat is appropriately dissipated into the space between the battery cells 20, allowing the battery cells 20 to be appropriately cooled. Furthermore, when the third bar portion 53 and the fourth bar portion 54 are not pressed, the electrode body 23 housed in the battery cell 20 is positioned near the end that is not pressed against the inner wall 22A of the case 22 of the battery cell 20. Therefore, the distance between the bar portions 50 can be made wider than if the bar portions 50 were located at a position where the inner wall 22A of the case 22 of the battery cell 20 and the electrode body 23 were in contact in a non-pressured state, thereby widening the cooling path. Also, the connection positions with the fin portions 55 provided on the third bar portion 53 and the fourth bar portion 54 are located more inward than the ends of the bar portions 50. Therefore, the third bar portion 53 and the fourth bar portion 54 can press into the case 22 of the battery cell 20 without being obstructed by the fin portions 55, thereby further holding the electrode body 23.

[0060] (1-2) The thickness of the third bar portion 53 and the fourth bar portion 54 corresponds to the distance between the inner wall 22A of the case 22 and the electrode body 23 in the non-pressed state. Therefore, when the spacer 13 is pressed against the battery cell 20, the third bar portion 53 and the fourth bar portion 54 further press into the case 22, enabling the electrode body 23 to be held in place even more.

[0061] (1-3) The first fin portion 56 and the second fin portion 57 are provided on the same bar portion 50. Therefore, the first fin portion 56 and the second fin portion 57 contact both adjacent battery cells 20, thereby ensuring insulation.

[0062] (1-4) The first fin portion 56 is inclined with respect to the first arrangement direction, and the second fin portion 57 is inclined with respect to the second arrangement direction. Therefore, the first fin portion 56 and the second fin portion 57 contact adjacent battery cells 20 at different positions, thereby ensuring insulation.

[0063] (Second embodiment) A second embodiment of the battery module and spacer will be described below with reference to Figures 8 and 9. The battery module and spacer of the second embodiment differ from those of the first embodiment in the space forming portion. The following description will focus on the differences from the first embodiment.

[0064] (Space forming part 13A) Next, the space forming portion 13A will be described in detail with reference to Figures 8 and 9. Figures 8 and 9 are cross-sectional views of the space forming portion 13A of the spacer 13. Figure 8 shows the space forming portion 13A in an uncompressed state together with the adjacent battery cells 20 on either side. Figure 9 shows the space forming portion 13A in a compressed state together with the adjacent battery cells 20 on either side.

[0065] As shown in FIG. 8 , the bar portion 30 includes, from top to bottom, a third bar portion 33, a first bar portion 31, a second bar portion 32, and a fourth bar portion 34. The battery cell 20 houses a wound electrode body 23 in a case 22. The ends of the electrode body 23 in the vertical direction (Z direction) are arc-shaped. Therefore, the distance between the inner wall 22A of the case 22 of the battery cell 20 and the electrode body 23 housed in the battery cell 20 increases as the distance approaches the top and bottom ends in the arrangement direction (Z direction) in which the bar portions 30 are arranged. Therefore, the third bar portion 33 and the fourth bar portion 34 are provided near the ends where the inner wall 22A of the case 22 of the battery cell 20 and the electrode body 23 housed in the battery cell 20 do not come into contact in an unpressured state in the orthogonal direction (X direction) perpendicular to the arrangement direction (Z direction) in which the bar portions 30 are arranged. The non-pressurized state is an uncompressed state in which the electrode body 23 is not pressed against the inner wall 22A of the case 22. The third bar portion 33 and the fourth bar portion 34 correspond to end bar portions. The fin portion 35 has a first fin portion 36, a second fin portion 37, a third fin portion 38, and a fourth fin portion 39.

[0066] The first bar portion 31 is provided with a first fin portion 36 and a second fin portion 37. The first fin portion 36 is inclined at a first angle θA with respect to a first arrangement direction (upward direction) in the arrangement direction (Z direction) in which the bar portions 30 are arranged, and extends in a first orthogonal direction (rightward in the figure) that is perpendicular to the arrangement direction (Z direction). The second fin portion 37 is inclined at a second angle θB with respect to a second arrangement direction (downward direction) that is opposite to the first arrangement direction, and extends in the first orthogonal direction (rightward in the figure). The first fin portion 36 and the second fin portion 37 are in contact with the surface 21 of the first battery cell 20A on the right side. The first angle θA and the second angle θB are the same angle.

[0067] The second bar portion 32 is provided with a third fin portion 38 and a fourth fin portion 39. The third fin portion 38 is inclined at a third angle θC with respect to the first arrangement direction (upward) and extends in a second orthogonal direction (leftward in the figure) that is opposite to the first orthogonal direction (rightward in the figure). The fourth fin portion 39 is inclined at a fourth angle θD with respect to the second arrangement direction (downward) and extends in the second orthogonal direction (leftward in the figure). The third fin portion 38 and the fourth fin portion 39 are in contact with the surface 21 of the second battery cell 20B on the left side. The third angle θC and the fourth angle θD are the same angle. The first angle θA and the third angle θC are the same angle.

[0068] A fourth fin portion 39 is provided on the third bar portion 33. The fourth fin portion 39 is inclined at a fourth angle θD with respect to the second arrangement direction (downward) and extends in the second orthogonal direction (leftward in the figure). The fourth fin portion 39 contacts the surface 21 of the second battery cell 20B on the left side.

[0069] The fourth bar portion 34 is provided with a first fin portion 36. The first fin portion 36 is inclined at a first angle θA with respect to the first arrangement direction (upward) and extends in a first orthogonal direction (rightward in the figure). The first fin portion 36 contacts the surface 21 of the first battery cell 20A on the right side.

[0070] The connection position between the first fin portion 36 provided on the first bar portion 31 and the first bar portion 31 is located at the end of the first bar portion 31 facing the first battery cell 20A in the orthogonal direction (X direction). The connection position between the second fin portion 37 provided on the first bar portion 31 and the first bar portion 31 is located at the end of the first bar portion 31 facing the first battery cell 20A in the orthogonal direction (X direction). The connection position between the third fin portion 38 provided on the second bar portion 52 and the second bar portion 32 is located at the end of the second bar portion 32 facing the second battery cell 20B in the orthogonal direction (X direction). The connection position between the fourth fin portion 39 provided on the second bar portion 32 and the second bar portion 32 is located at the end of the second bar portion 32 facing the second battery cell 20B in the orthogonal direction (X direction).

[0071] The connection position between the fourth fin portion 39 provided on the third bar portion 33 and the third bar portion 33 is located more inward in the orthogonal direction (X direction) than the end of the third bar portion 33. Similarly, the connection position between the first fin portion 36 provided on the fourth bar portion 34 and the fourth bar portion 34 is located more inward in the orthogonal direction (X direction) than the end of the fourth bar portion 34.

[0072] (uncompressed state) As shown in Fig. 8, in the uncompressed state, the tips of the first fin portion 36 and the second fin portion 37 on the first bar portion 31 protrude further toward the first battery cell 20A on the right side of the first bar portion 31 in the figure. In addition, in the uncompressed state, the tips of the third fin portion 38 and the fourth fin portion 39 on the second bar portion 32 protrude further toward the second battery cell 20B on the left side of the second bar portion 32. The tip of the third fin portion 38 on the third bar portion 33 protrudes further toward the second battery cell 20B on the left side of the third bar portion 33. The tip of the first fin portion 36 on the fourth bar portion 34 protrudes further toward the first battery cell 20A on the right side of the fourth bar portion 34. The first bar portion 31, the second bar portion 32, the third bar portion 33, and the fourth bar portion 34 are not in contact with the surface 21 of the first battery cell 20A on the right side or the surface 21 of the second battery cell 20B on the left side.

[0073] The first fin length LA, which is the length of the first fin portion 36 from the first bar portion 31, and the fourth fin length LD, which is the length of the fourth fin portion 39 from the third bar portion 33, are both shorter than the interval P between the first bar portion 31 and the third bar portion 33 (LA < P, LD < P). The first fin length LA and the fourth fin length LD are of the same length (LA = LD). The sum of the first fin length LA and the fourth fin length LD is longer than the interval P between the first bar portion 31 and the third bar portion 33 (LA + LD > P).

[0074] The second fin length LB, which is the length of the second fin portion 37 from the first bar portion 31, and the third fin length LC, which is the length of the third fin portion 38 from the second bar portion 32, are both shorter than the interval P between the first bar portion 31 and the second bar portion 32 (LB < P, LC < P). The second fin length LB and the third fin length LC are of the same length (LB = LC). The sum of the second fin length LB and the third fin length LC is longer than the interval P between the first bar portion 31 and the second bar portion 32 (LB + LC > P).

[0075] The fourth fin length LD, which is the length of the fourth fin portion 39 from the second bar portion 32, and the first fin length LA, which is the length of the first fin portion 36 from the fourth bar portion 34, are both shorter than the interval P between the second bar portion 32 and the fourth bar portion 34 (LD < P, LA < P). The fourth fin length LD and the first fin length LA are of the same length (LD = LA). The sum of the fourth fin length LD and the first fin length LA is longer than the interval P between the second bar portion 32 and the fourth bar portion 34 (LD + LA > P).

[0076] The sum of the projection lengths LZA and LZD in the arrangement direction (Z direction) of the first fin portion 36 and the fourth fin portion 39 is shorter than the interval P between the first bar portion 31 and the third bar portion 33 in the non-compressed state (LZA + LZD < P). Therefore, in the non-compressed state, a gap G is provided in the arrangement direction (Z direction) between the tips of the first fin portion 36 and the fourth fin portion 39. As a result, the first fin portion 36 and the fourth fin portion 39 do not overlap in the arrangement direction (Z direction). Such a spacer 13 can be manufactured at a low cost.

[0077] The total of the projection length LZB in the arrangement direction (Z direction) of the second fin portion 37 and the projection length LZC in the arrangement direction (Z direction) of the third fin portion 38 is shorter than the interval P between the first bar portion 31 and the second bar portion 32 in the non-compressed state (LZB + LZC < P). For this reason, in the non-compressed state, a gap G is provided in the arrangement direction (Z direction) between the tips of the second fin portion 37 and the third fin portion 38. Thereby, the second fin portion 37 and the third fin portion 38 are prevented from overlapping in the arrangement direction (Z direction). Such a spacer 13 can be manufactured at a low cost.

[0078] The total of the projection length LZD in the arrangement direction (Z direction) of the fourth fin portion 39 and the projection length LZA in the arrangement direction (Z direction) of the first fin portion 36 is shorter than the interval P between the second bar portion 32 and the fourth bar portion 34 in the non-compressed state (LZD + LZA < P). For this reason, in the non-compressed state, a gap G is provided in the arrangement direction (Z direction) between the tips of the fourth fin portion 39 and the first fin portion 36. Thereby, the fourth fin portion 39 and the first fin portion 36 are prevented from overlapping in the arrangement direction (Z direction). Such a spacer 13 can be manufactured at a low cost.

[0079] (Compressed state) As shown in FIG. 9, in the compressed state, the right side surface of the bar portion 30 is in contact with the surface 21 of the right first battery cell 20A. The surface 21 of the left second battery cell 20B is in contact with the left side surface of the bar portion 30. That is, in the compressed state, the bar portion 30 is sandwiched between the surface 21 of the first battery cell 20A and the surface 21 of the second battery cell 20B, and thus is compressed in the stacking direction (X direction). Further, the bar portion 30 presses the surface 21 of the first battery cell 20A and the surface 21 of the second battery cell 20B in a direction away from each other by the reaction force against the compression. Thereby, the contact between the adjacent battery cells 20 on both sides is suppressed by the bar portion 30. And a space 15 in which the surfaces 21 of the battery cells 20 adjacent to both sides of the spacer 13 are separated is formed between two adjacent bar portions 30 vertically.

[0080] Because the surface 21 of the first right battery cell 20A is in contact with the right side surface of the first bar 31, the first fin 36 provided on the first bar 31 is pressed to the left by the surface 21 of the first right battery cell 20A. Due to this pressing, the first fin 36 is bent more to the left than in the uncompressed state along the surface 21 of the first right battery cell 20A. In this bent state, the first fin 36 extends upward along the surface 21 of the first right battery cell 20A. The reaction force from this bending causes the bent first fin 36 to press the surface 21 of the first right battery cell 20A to the right.

[0081] Because the surface 21 of the first right battery cell 20A is in contact with the right side surface of the first bar 31, the second fin 37 provided on the first bar 31 is pressed to the left by the surface 21 of the first right battery cell 20A. Due to this pressing, the second fin 37 is bent more to the left than in the uncompressed state along the surface 21 of the first right battery cell 20A. In this bent state, the second fin 37 extends downward along the surface 21 of the first right battery cell 20A. In this bent state, the second fin 37 presses the surface 21 of the first right battery cell 20A to the right due to the reaction force of the bending.

[0082] Because the surface 21 of the second left battery cell 20B is in contact with the left side surface of the second bar portion 32, the third fin portion 38 provided on the second bar portion 32 is pressed to the right by the surface 21 of the second left battery cell 20B. Due to this pressing, the third fin portion 38 is bent more to the right than in the uncompressed state along the surface 21 of the second left battery cell 20B. In this bent state, the third fin portion 38 extends upward along the surface 21 of the second left battery cell 20B. In this bent state, the third fin portion 38 presses the surface 21 of the second left battery cell 20B to the left due to the reaction force of the bending.

[0083] Because the surface 21 of the second left battery cell 20B is in contact with the left side surface of the second bar portion 32, the fourth fin portion 39 provided on the second bar portion 32 is pressed to the right by the surface 21 of the second left battery cell 20B. Due to this pressing, the fourth fin portion 39 is bent more to the right than in the uncompressed state along the surface 21 of the second left battery cell 20B. In this bent state, the fourth fin portion 39 extends downward along the surface 21 of the second left battery cell 20B. The reaction force from this bending causes the fourth fin portion 39 to press the surface 21 of the second left battery cell 20B to the left.

[0084] Because the surface 21 of the second left battery cell 20B is in contact with the left side surface of the third bar portion 33, the fourth fin portion 39 provided on the third bar portion 33 is pressed to the right by the surface 21 of the second left battery cell 20B. Due to this pressing, the fourth fin portion 39 is bent more to the right than in the uncompressed state along the surface 21 of the second left battery cell 20B. In this bent state, the fourth fin portion 39 extends downward along the surface 21 of the second left battery cell 20B. The reaction force of this bending causes the bent fourth fin portion 39 to press the surface 21 of the second left battery cell 20B to the left.

[0085] Because the surface 21 of the first right battery cell 20A is in contact with the right side surface of the fourth bar 34, the first fin 36 provided on the fourth bar 34 is pressed to the left by the surface 21 of the first right battery cell 20A. Due to this pressing, the first fin 36 is bent more to the left than in the uncompressed state along the surface 21 of the first right battery cell 20A. In this bent state, the first fin 36 extends upward along the surface 21 of the first right battery cell 20A. In this bent state, the first fin 36 presses the surface 21 of the first right battery cell 20A to the right due to the reaction force of the bending.

[0086] As described above, the first fin length LA of the first fin portion 36 and the fourth fin length LD of the fourth fin portion 39 are both shorter than the distance P between the first bar portion 31 and the third bar portion 33. Therefore, there is a portion of the surface 21 of the first right-side battery cell 20A that is not covered by the first fin portion 36 within the distance P between the first bar portion 31 and the third bar portion 33. Similarly, there is a portion of the surface 21 of the second left-side battery cell 20B that is not covered by the fourth fin portion 39 within the distance P between the first bar portion 31 and the third bar portion 33.

[0087] Similarly, the second fin length LB of the second fin portion 37 and the third fin length LC of the third fin portion 38 are both shorter than the distance P between the first bar portion 31 and the second bar portion 32. Therefore, there is a portion of the surface 21 of the first right-side battery cell 20A that is not covered by the second fin portion 37 within the distance P between the first bar portion 31 and the second bar portion 32. Furthermore, there is a portion of the surface 21 of the second left-side battery cell 20B that is not covered by the third fin portion 38 within the distance P between the first bar portion 31 and the second bar portion 32.

[0088] Similarly, the fourth fin length LD of the fourth fin portion 39 and the first fin length LA of the first fin portion 36 are both shorter than the distance P between the second bar portion 32 and the fourth bar portion 34. Therefore, there is a portion of the surface 21 of the second left battery cell 20B that is not covered by the fourth fin portion 39 within the distance P between the second bar portion 32 and the fourth bar portion 34. Also, there is a portion of the surface 21 of the first right battery cell 20A that is not covered by the first fin portion 36 within the distance P between the second bar portion 32 and the fourth bar portion 34.

[0089] Therefore, the surfaces 21 of the battery cells 20 on both sides of the spacer 13 have portions exposed to the space 15 at the interval P between the bar portions 30. In other words, when the battery cells 20 on both sides of the spacer 13 generate heat, they can dissipate the heat into the space 15. The space 15 is a passageway for cooling gas in the battery module 10, through which gas for cooling the battery cells 20 flows. As a result, the spacer 13 can cool the battery cells 20 on both sides while preventing the temperature difference between the adjacent battery cells 20 from becoming too large.

[0090] As described above, the sum of the first fin length LA of the first fin portion 36 and the fourth fin length LD of the fourth fin portion 39 is longer than the distance P between the first bar portion 31 and the third bar portion 33. Therefore, in the compressed state, the first fin portion 36 and the fourth fin portion 39 overlap in the arrangement direction (Z direction). That is, there is an overlap L between the tip of the first fin portion 36 and the tip of the fourth fin portion 39. Therefore, the first fin portion 36 presses at least a region of the first right battery cell 20A that faces a region of the second left battery cell 20B that is not pressed by the fourth fin portion 39. The fourth fin portion 39 presses at least a region of the second left battery cell 20B that faces a region of the first right battery cell 20A that is not pressed by the first fin portion 36. In other words, the battery cells 20 on either side of the spacer 13 have no gap in the arrangement direction (Z direction) at the interval P between the bar portions 30, and are pressed away from each other by at least one of the first fin portion 36 and the fourth fin portion 39. Furthermore, the battery cells 20 on either side of the spacer 13 do not come into contact with each other between the first bar portion 31 and the third bar portion 33. For example, even if the adjacent battery cells 20 expand and enter the space 15 while bending their respective first fin portion 36 and fourth fin portion 39, at least one of the first fin portion 36 and the fourth fin portion 39 will always be present between the adjacent battery cells 20. This allows the spacer 13 to reliably maintain insulation between the adjacent battery cells 20 on either side.

[0091] Similarly, the sum of the second fin length LB of the second fin portion 37 and the third fin length LC of the third fin portion 38 is longer than the distance P between the first bar portion 31 and the second bar portion 32. Therefore, in the compressed state, the second fin portion 37 and the third fin portion 38 overlap in the arrangement direction (Z direction). That is, there is an overlap L between the tip of the second fin portion 37 and the tip of the third fin portion 38. Therefore, the second fin portion 37 presses at least a region of the first right-side battery cell 20A that faces a region of the second left-side battery cell 20B that is not pressed by the third fin portion 38. The third fin portion 38 presses at least a region of the second left-side battery cell 20B that faces a region of the first right-side battery cell 20A that is not pressed by the second fin portion 37. In other words, the battery cells 20 on either side of the spacer 13 have no gap in the arrangement direction (Z direction) at the interval P between the bar portions 30, and are pressed away from each other by at least one of the second fin portion 37 and the third fin portion 38. Furthermore, the battery cells 20 on either side of the spacer 13 do not come into contact with each other between the first bar portion 31 and the second bar portion 32. For example, even if the adjacent battery cells 20 expand and enter the space 15 while bending their respective second fin portions 37 and third fin portions 38, at least one of the second fin portion 37 and the third fin portion 38 will always be present between the adjacent battery cells 20. This allows the spacer 13 to reliably maintain insulation between the adjacent battery cells 20.

[0092] Similarly, the sum of the fourth fin length LD of the fourth fin portion 39 and the first fin length LA of the first fin portion 36 is longer than the distance P between the second bar portion 32 and the fourth bar portion 34. Therefore, in the compressed state, the fourth fin portion 39 and the first fin portion 36 overlap in the arrangement direction (Z direction). That is, there is an overlap L between the tip of the fourth fin portion 39 and the tip of the first fin portion 36. Therefore, the first fin portion 36 presses at least a region of the first right battery cell 20A that faces a region of the second left battery cell 20B that is not pressed by the fourth fin portion 39. The fourth fin portion 39 presses at least a region of the second left battery cell 20B that faces a region of the first right battery cell 20A that is not pressed by the first fin portion 36. In other words, the battery cells 20 on either side of the spacer 13 have no gap in the arrangement direction (Z direction) at the interval P between the bar portions 30, and are pressed away from each other by at least one of the first fin portion 36 and the fourth fin portion 39. Furthermore, the battery cells 20 on either side of the spacer 13 do not come into contact with each other between the second bar portion 32 and the fourth bar portion 34. For example, even if the adjacent battery cells 20 expand and enter the space 15 while bending their respective fourth fin portions 39 and first fin portions 36, at least one of the fourth fin portion 39 and the first fin portion 36 will always be present between the adjacent battery cells 20. This allows the spacer 13 to reliably maintain insulation between the adjacent battery cells 20 on either side.

[0093] When compressed, the first fin portion 36 and the second fin portion 37 on the first bar portion 31 are pressed by the first battery cell 20A on the right side. At this time, both the first fin portion 36 and the second fin portion 37 are pressed to the left. Therefore, if the first bar portion 31 is used as the center of rotation, the force from the first fin portion 36 to the first bar portion 31 and the force from the second fin portion 37 to the first bar portion 31 are in opposite directions and cancel each other out. This prevents the first bar portion 31 from rotating.

[0094] Similarly, the third fin portion 38 and the fourth fin portion 39 on the second bar portion 32 are pressed by the second battery cell 20B on the left side during compression. At this time, both the third fin portion 38 and the fourth fin portion 39 are pressed to the right. Therefore, if the second bar portion 32 is used as the center of rotation, the force from the third fin portion 38 to the second bar portion 32 and the force from the fourth fin portion 39 to the second bar portion 32 are in opposite directions and cancel each other out. This prevents the second bar portion 32 from rotating.

[0095] Even if the battery cell 20 expands for some reason, the spacer 13 can prevent the battery cell 20 from entering the space 15 by the first fin portion 36, the second fin portion 37, the third fin portion 38, and the fourth fin portion 39 pressing against the battery cell 20. In other words, even if the battery cell 20 expands, the spacer 13 can prevent the length of the space 15 in the stacking direction (X direction) from becoming narrower, thereby ensuring an appropriate space 15. Therefore, the spacer 13 can prevent the flow rate of the cooling gas flowing through the space 15 from decreasing due to the expansion of the battery cell 20. Therefore, the spacer 13 can prevent a decrease in the cooling function of the cooling gas flowing through the space 15 for the battery cell 20 from decreasing. Furthermore, even if the battery cell 20 expands for some reason, the third bar portion 53 and the fourth bar portion 54 can press the case 22 of the battery cell 20, thereby holding the electrode body 23.

[0096] Next, the effects of the second embodiment will be described. (2-1) The first fin portion 36 and the second fin portion 37 contact the surface 21 of the first battery cell 20A, thereby ensuring an appropriate distance from the surface 21 of the first battery cell 20A, and the third fin portion 38 and the fourth fin portion 39 contact the surface 21 of the second battery cell 20B, thereby ensuring an appropriate distance from the surface 21 of the second battery cell 20B. Therefore, the spacer 13 can ensure an appropriate distance between adjacent battery cells 20. As a result, heat is appropriately dissipated into the space between the battery cells 20, allowing the battery cells 20 to be appropriately cooled. Furthermore, when the third bar portion 33 and the fourth bar portion 34 are not pressed, the electrode body 23 housed in the battery cell 20 is positioned near the end that is not pressed against the inner wall 22A of the case 22 of the battery cell 20. This allows the spacing between the bar portions 30 to be wider than if the inner wall 22A of the case 22 of the battery cell 20 and the electrode body 23 were in contact in a non-pressured state, thereby widening the cooling path. Also, the connection positions with the fin portions 35 provided on the third bar portion 33 and the fourth bar portion 34 are located more inward than the ends of the bar portions 30. This allows the third bar portion 33 and the fourth bar portion 34 to press into the case 22 of the battery cell 20 without being obstructed by the fin portions 35, thereby further supporting the electrode body 23.

[0097] (2-2) The thickness of the third bar portion 33 and the fourth bar portion 34 corresponds to the distance between the inner wall 22A of the case 22 and the electrode body 23 in the non-pressed state. Therefore, when the spacer 13 is pressed against the battery cell 20, the third bar portion 33 and the fourth bar portion 34 further press into the case 22, enabling the electrode body 23 to be held in place even more.

[0098] (2-3) The first fin portion 36 and the second fin portion 37, which correspond to the first fin portion, are provided on the first bar portion 31, and the third fin portion 38 and the fourth fin portion 39, which correspond to the second fin portion, are provided on the second bar portion 32, which is different from the first bar portion 31. Therefore, the fin portion 35 provided on the first bar portion 31 and the fin portion 35 provided on the second bar portion 32 are in contact with both of the adjacent battery cells 20 separately, thereby ensuring insulation.

[0099] (2-4) The first bar portion 31 is provided with a first fin portion 36 that is inclined with respect to the first arrangement direction and a second fin portion 37 that is inclined with respect to the second arrangement direction, and the second bar portion 32 is provided with a third fin portion 38 that is inclined with respect to the first arrangement direction and a fourth fin portion 39 that is inclined with respect to the second arrangement direction. As a result, at least two fin portions 35 from each bar portion 30 come into contact with the battery cells 20. This ensures insulation between adjacent battery cells 20.

[0100] (Third embodiment) A third embodiment of a battery module and a spacer will be described below with reference to Figures 10 and 11. The battery module and spacer of the third embodiment differ from those of the first embodiment in the space-forming portion. The following description will focus on the differences from the first embodiment.

[0101] (Space forming part 13B) 10 and 11 are cross-sectional views of the space-forming portion 13B of the spacer 13. Fig. 10 shows the space-forming portion 13B in an uncompressed state together with the adjacent battery cells 20 on either side. Fig. 11 shows the space-forming portion 13B in a compressed state together with the adjacent battery cells 20 on either side.

[0102] As shown in FIG. 10 , the bar portion 40 includes, from top to bottom, a third bar portion 43, a first bar portion 41, a second bar portion 42, and a fourth bar portion 44. The battery cell 20 houses a wound electrode body 23 in a case 22. The ends of the electrode body 23 in the vertical direction (Z direction) are arc-shaped. Therefore, the distance between the inner wall 22A of the case 22 of the battery cell 20 and the electrode body 23 housed in the battery cell 20 increases as the distance approaches the top and bottom ends in the arrangement direction (Z direction) in which the bar portions 30 are arranged. Therefore, the third bar portion 33 and the fourth bar portion 34 are provided near the ends where the inner wall 22A of the case 22 of the battery cell 20 and the electrode body 23 housed in the battery cell 20 do not come into contact in an unpressured state in the orthogonal direction (X direction) perpendicular to the arrangement direction (Z direction) in which the bar portions 30 are arranged. The non-pressurized state is an uncompressed state in which the electrode body 23 is not pressed against the inner wall 22A of the case 22. The third bar portion 43 and the fourth bar portion 44 correspond to end bar portions. The fin portion 45 has a first fin portion 46A, a first stopper portion 46B, a second fin portion 47A, a second stopper portion 47B, a third fin portion 48, and a fourth fin portion 49.

[0103] The first bar portion 41 is provided with a first fin portion 46A and a first stopper portion 46B. The first fin portion 46A is inclined at a first angle θA with respect to a first arrangement direction (downward direction) in the arrangement direction (Z direction) in which the bar portions 40 are arranged, and extends in a first orthogonal direction (rightward in the figure) that is perpendicular to the arrangement direction (Z direction). The first stopper portion 46B is formed to extend in a second arrangement direction (upward) that is opposite to the first arrangement direction. The first fin portion 46A contacts the surface 21 of the first battery cell 20A on the right side in the figure. It is desirable that the first stopper portion 46B does not deform when compressed, so the thickness of the first stopper portion 46B is preferably greater than the thickness of the first fin portion 46A.

[0104] The second bar portion 42 is provided with a second fin portion 47A and a second stopper portion 47B. The second fin portion 47A is inclined at a second angle θB with respect to the second arrangement direction (upward) and extends in a second orthogonal direction (leftward in the figure) opposite to the first orthogonal direction (rightward in the figure). The second stopper portion 47B is formed to extend in the first arrangement direction (downward). The second fin portion 47A contacts the surface 21 of the second battery cell 20B on the left side in the figure. The first angle θA and the second angle θB are the same angle. It is desirable that the second stopper portion 47B does not deform when compressed, so the thickness of the second stopper portion 47B is preferably greater than the thickness of the second fin portion 47A.

[0105] The third bar portion 43 is provided with a third fin portion 48. The third fin portion 48 is inclined at a third angle θC with respect to the first arrangement direction (downward) and extends in the second orthogonal direction (leftward in the figure). The third fin portion 48 contacts the surface 21 of the second battery cell 20B on the left side.

[0106] A fourth fin portion 49 is provided on the fourth bar portion 44. The fourth fin portion 49 is inclined at a fourth angle θD with respect to the second arrangement direction (upward) and extends in the first orthogonal direction (rightward in the figure). The fourth fin portion 49 contacts the surface 21 of the first battery cell 20A on the right side.

[0107] The connection position between the first fin portion 46A provided on the first bar portion 41 and the first bar portion 41 is located at the end of the first bar portion 41 facing the first battery cell 20A in the orthogonal direction (X direction). The connection position between the first stopper portion 46B provided on the first bar portion 41 and the first bar portion 41 is located at the end of the first bar portion 41 facing the first battery cell 20A in the orthogonal direction (X direction). The connection position between the second fin portion 47A provided on the second bar portion 42 and the second bar portion 42 is located at the end of the second bar portion 42 facing the second battery cell 20B in the orthogonal direction (X direction). The connection position between the second stopper portion 47B provided on the second bar portion 42 and the second bar portion 42 is located at the end of the second bar portion 42 facing the second battery cell 20B in the orthogonal direction (X direction).

[0108] The connection position between the third fin portion 48 provided on the third bar portion 43 and the third bar portion 43 is located inside the end of the third bar portion 43 in the orthogonal direction (X direction). Similarly, the connection position between the fourth fin portion 49 provided on the fourth bar portion 44 and the fourth bar portion 44 is located inside the end of the fourth bar portion 44 in the orthogonal direction (X direction).

[0109] (Non-compressed state) As shown in FIG. 10, in the non-compressed state, the tip of the first fin portion 46A provided on the first bar portion 41 protrudes toward the first battery cell 20A on the right side of the first bar portion 41 in the figure. In the non-compressed state, the tip of the second fin portion 47A provided on the second bar portion 42 protrudes toward the second battery cell 20B on the left side of the second bar portion 42. In the non-compressed state, the tip of the third fin portion 48 provided on the third bar portion 43 protrudes toward the second battery cell 20B on the left side of the third bar portion 43. In the non-compressed state, the tip of the fourth fin portion 49 provided on the fourth bar portion 44 protrudes toward the first battery cell 20A on the right side of the fourth bar portion 44. The first bar portion 41, the second bar portion 42, the third bar portion 43, and the fourth bar portion 44 do not contact the surface 21 of the first battery cell 20A on the right side or the surface 21 of the second battery cell 20B on the left side.

[0110] The first fin length LA, which is the length of the first fin portion 46A from the first bar portion 41, and the second fin length LB, which is the length of the second fin portion 47A from the second bar portion 42, are both shorter than the distance P between the first bar portion 41 and the second bar portion 42 (LA < P, LB < P). The sum of the first fin length LA and the second fin length LB is longer than the distance P between the first bar portion 41 and the second bar portion 42 (LA + LB > P).

[0111] The third fin length LC, which is the length of the third fin portion 48 from the third bar portion 43, and the fifth fin length LE, which is the length of the first stopper portion 46B from the first bar portion 41, are both shorter than the distance P between the first bar portion 41 and the third bar portion 43 (LC < P, LE < P). The sum of the third fin length LC and the fifth fin length LE is longer than the distance P between the first bar portion 41 and the third bar portion 43 (LC + LE > P).

[0112] The sixth fin length LF, which is the length from the second bar portion 42 of the second stopper portion 47B, and the fourth fin length LD, which is the length from the fourth bar portion 44 of the fourth fin portion 49, are both shorter than the interval P between the second bar portion 42 and the fourth bar portion 44 (LF < P, LD < P). The sum of the sixth fin length LF and the fourth fin length LD is longer than the interval P between the second bar portion 42 and the fourth bar portion 44 (LF + LD > P).

[0113] The sum of the projection lengths LZA and LZB in the arrangement direction (Z direction) of the first fin portion 46A and the second fin portion 47A is shorter than the interval P between the first bar portion 41 and the second bar portion 42 in the non-compressed state (LZA + LZB < P). Therefore, in the non-compressed state, a gap G1 is provided in the arrangement direction (Z direction) between the tips of the first fin portion 46A and the second fin portion 47A. As a result, the first fin portion 46A and the second fin portion 47A do not overlap in the arrangement direction (Z direction). Such a spacer 13 can be manufactured at a low cost.

[0114] The sum of the projection length LZC in the arrangement direction (Z direction) of the third fin portion 48 and the fifth fin length LE of the first stopper portion 46B is shorter than the interval P between the first bar portion 41 and the third bar portion 43 in the non-compressed state (LZC + LE < P). Therefore, in the non-compressed state, a gap G2 is provided in the arrangement direction (Z direction) between the tips of the third fin portion 48 and the first stopper portion 46B. As a result, the third fin portion 48 and the first stopper portion 46B do not overlap in the arrangement direction (Z direction). Such a spacer 13 can be manufactured at a low cost.

[0115] The total of the projection length LZD in the array direction (Z direction) of the fourth fin portion 49 and the sixth fin length LF of the second stopper portion 47B is shorter than the interval P between the second bar portion 42 and the fourth bar portion 44 in the non-compressed state (LZD + LF < P). Therefore, in the non-compressed state, a gap G3 is provided in the array direction (Z direction) between the tips of the fourth fin portion 49 and the second stopper portion 47B. As a result, the fourth fin portion 49 and the second stopper portion 47B are prevented from overlapping in the array direction (Z direction). Such a spacer 13 can be manufactured at a low cost.

[0116] (Compressed state) As shown in FIG. 11, in the compressed state, the right side surface of the bar portion 40 is in contact with the surface 21 of the right first battery cell 20A. The surface 21 of the left second battery cell 20B is in contact with the left side surface of the bar portion 40. That is, in the compressed state, the bar portion 40 is sandwiched between the surface 21 of the first battery cell 20A and the surface 21 of the second battery cell 20B, and is compressed in the stacking direction (X direction). Further, the bar portion 40 presses the surface 21 of the first battery cell 20A and the surface 21 of the second battery cell 20B away from each other by the reaction force against the compression. As a result, the contact between the adjacent battery cells 20 on both sides is suppressed by the bar portion 40. And a space 15 is formed between the surface 21 of the battery cells 20 adjacent to both sides of the spacer 13 between the two bar portions 40 adjacent to each other vertically.

[0117] Since the surface 21 of the right first battery cell 20A is in contact with the right side surface of the first bar portion 41, the first fin portion 46A provided on the first bar portion 41 is pressed to the left by the surface 21 of the right first battery cell 20A. By this pressing, the first fin portion 46A is in a state of being bent to the left more than in the non-compressed state along the surface 21 of the right first battery cell 20A. The bent first fin portion 46A extends downward along the surface 21 of the right first battery cell 20A. And the bent first fin portion 46A presses the surface 21 of the right first battery cell 20A to the right by the reaction force of the bending.

[0118] Because the surface 21 of the second left battery cell 20B is in contact with the left side surface of the second bar portion 42, the second fin portion 47A provided on the second bar portion 42 is pressed to the right by the surface 21 of the second left battery cell 20B. Due to this pressing, the second fin portion 47A is bent more to the right than in the uncompressed state along the surface 21 of the second left battery cell 20B. In this bent state, the second fin portion 47A extends upward along the surface 21 of the second left battery cell 20B. The reaction force of the bending of the second fin portion 47A presses the surface 21 of the second left battery cell 20B to the left.

[0119] Because the surface 21 of the second left battery cell 20B is in contact with the left side surface of the third bar portion 43, the third fin portion 48 provided on the third bar portion 43 is pressed to the right by the surface 21 of the second left battery cell 20B. Due to this pressing, the third fin portion 48 is bent more to the right than in the uncompressed state along the surface 21 of the second left battery cell 20B. In this bent state, the third fin portion 48 extends downward along the surface 21 of the second left battery cell 20B. In this bent state, the third fin portion 48 presses the surface 21 of the second left battery cell 20B to the left due to the reaction force of the bending.

[0120] Because the surface 21 of the first right battery cell 20A is in contact with the right side surface of the fourth bar portion 44, the fourth fin portion 49 provided on the fourth bar portion 44 is pressed to the right by the surface 21 of the first right battery cell 20A. Due to this pressing, the fourth fin portion 49 is bent more to the left than in the uncompressed state along the surface 21 of the first right battery cell 20A. In this bent state, the fourth fin portion 49 extends upward along the surface 21 of the first right battery cell 20A. In this bent state, the fourth fin portion 49 presses the surface 21 of the first right battery cell 20A to the right due to the reaction force of the bending.

[0121] As described above, the first fin length LA of the first fin portion 46A and the second fin length LB of the second fin portion 47A are both shorter than the distance P between the first bar portion 41 and the second bar portion 42. Therefore, there is a portion of the surface 21 of the first right-side battery cell 20A that is not covered by the first fin portion 46A within the distance P between the first bar portion 41 and the second bar portion 42. Similarly, there is a portion of the surface 21 of the second left-side battery cell 20B that is not covered by the second fin portion 47A within the distance P between the first bar portion 41 and the second bar portion 42.

[0122] Similarly, the third fin length LC of the third fin portion 48 and the fifth fin length LE of the first stopper portion 46B are both shorter than the distance P between the first bar portion 41 and the third bar portion 43. Therefore, there is a portion of the surface 21 of the first right-side battery cell 20A that is not covered by the first stopper portion 46B within the distance P between the first bar portion 41 and the third bar portion 43. Furthermore, there is a portion of the surface 21 of the second left-side battery cell 20B that is not covered by the third fin portion 48 within the distance P between the first bar portion 41 and the third bar portion 43.

[0123] Similarly, the sixth fin length LF of the second stopper portion 47B and the fourth fin length LD of the fourth fin portion 49 are both shorter than the distance P between the second bar portion 42 and the fourth bar portion 44. Therefore, there is a portion of the surface 21 of the second left battery cell 20B that is not covered by the second stopper portion 47B within the distance P between the second bar portion 42 and the fourth bar portion 44. Furthermore, there is a portion of the surface 21 of the first right battery cell 20A that is not covered by the fourth fin portion 49 within the distance P between the second bar portion 42 and the fourth bar portion 44.

[0124] Therefore, the surfaces 21 of the battery cells 20 on both sides of the spacer 13 have portions exposed to the space 15 in the gap between the bar portions 40. In other words, when the battery cells 20 on both sides of the spacer 13 generate heat, they can dissipate the heat into the space 15. The space 15 is a passageway for cooling gas in the battery module 10, through which gas for cooling the battery cells 20 flows. As a result, the spacer 13 can cool the battery cells 20 on both sides while preventing the temperature difference between the adjacent battery cells 20 from becoming too large.

[0125] As described above, the sum of the fifth fin length LE of the first stopper portion 46B and the third fin length LC of the third fin portion 48 is longer than the distance P between the first bar portion 41 and the third bar portion 43. Therefore, in the compressed state, the first stopper portion 46B and the third fin portion 48 overlap in the arrangement direction (Z direction). That is, there is an overlap L2 between the tip of the first stopper portion 46B and the tip of the third fin portion 48. Therefore, the first stopper portion 46B presses at least a region of the first right battery cell 20A that faces a region of the second left battery cell 20B that is not pressed by the third fin portion 48. The third fin portion 48 presses at least a region of the second left battery cell 20B that faces a region of the first right battery cell 20A that is not pressed by the first stopper portion 46B. In other words, there is no gap between the battery cells 20 on either side of the spacer 13 in the arrangement direction (Z direction) at the distance P between the first bar portion 41 and the third bar portion 43, and the battery cells 20 on either side of the spacer 13 are pressed away from each other by at least one of the first stopper portion 46B and the third fin portion 48. Furthermore, the battery cells 20 on either side of the spacer 13 do not come into contact with each other between the first bar portion 41 and the third bar portion 43. For example, even if the adjacent battery cells 20 expand and enter the space 15 while bending the first stopper portion 46B and the third fin portion 48, at least one of the first stopper portion 46B and the third fin portion 48 will always be present between the adjacent battery cells 20 on either side. This allows the spacer 13 to reliably maintain insulation between the adjacent battery cells 20 on either side.

[0126] Similarly, the sum of the first fin length LA of the first fin portion 46A and the second fin length LB of the second fin portion 47A is longer than the distance P between the first bar portion 41 and the second bar portion 42. Therefore, in the compressed state, the first fin portion 46A and the second fin portion 47A overlap in the arrangement direction (Z direction). That is, there is an overlap L1 between the tip of the first fin portion 46A and the tip of the second fin portion 47A. Therefore, the first fin portion 46A presses at least a region of the first right battery cell 20A that faces a region of the second left battery cell 20B that is not pressed by the second fin portion 47A. The second fin portion 47A presses at least a region of the second left battery cell 20B that faces a region of the first right battery cell 20A that is not pressed by the first fin portion 46A. In other words, the battery cells 20 on either side of the spacer 13 have no gap in the arrangement direction (Z direction) at the distance P between the first bar portion 41 and the second bar portion 42, and are pressed away from each other by at least one of the first fin portion 46A and the second fin portion 47A. Furthermore, the battery cells 20 on either side of the spacer 13 do not come into contact with each other between the first bar portion 41 and the second bar portion 42. For example, even if the adjacent battery cells 20 expand and enter the space 15 while bending their respective first fin portions 46A and second fin portions 47A, at least one of the first fin portion 46A and the second fin portion 47A will always be present between the adjacent battery cells 20. This allows the spacer 13 to reliably maintain insulation between the adjacent battery cells 20.

[0127] Similarly, the sum of the sixth fin length LF of the second stopper portion 47B and the fourth fin length LD of the fourth fin portion 49 is longer than the distance P between the second bar portion 42 and the fourth bar portion 44. Therefore, in the compressed state, the second stopper portion 47B and the fourth fin portion 49 overlap in the arrangement direction (Z direction). That is, an overlap L3 is provided between the tip of the second stopper portion 47B and the tip of the fourth fin portion 49. Therefore, the second stopper portion 47B presses at least a region of the first right battery cell 20A that faces a region of the second left battery cell 20B that is not pressed by the fourth fin portion 49. The fourth fin portion 49 presses at least a region of the second left battery cell 20B that faces a region of the first right battery cell 20A that is not pressed by the second stopper portion 47B. In other words, there is no gap between the battery cells 20 on either side of the spacer 13 in the arrangement direction (Z direction) at the distance P between the second bar portion 42 and the fourth bar portion 44, and the battery cells 20 on either side of the spacer 13 are pressed away from each other by at least one of the second stopper portion 47B and the fourth fin portion 49. Furthermore, the battery cells 20 on either side of the spacer 13 do not come into contact with each other between the second bar portion 42 and the fourth bar portion 44. For example, even if the battery cells 20 on either side expand and enter the space 15 while bending the second stopper portion 47B and the fourth fin portion 49, at least one of the second stopper portion 47B and the fourth fin portion 49 will always be present between the adjacent battery cells 20 on either side. This allows the spacer 13 to reliably maintain insulation between the adjacent battery cells 20 on either side.

[0128] Even if the battery cell 20 expands for some reason, the spacer 13 can prevent the battery cell 20 from entering the space 15 by the first fin portion 46A, the first stopper portion 46B, the second fin portion 47A, the second stopper portion 47B, the third fin portion 48, and the fourth fin portion 49 pressing against the battery cell 20. In other words, even if the battery cell 20 expands, the spacer 13 can prevent the length of the space 15 in the stacking direction (X direction) from becoming narrower, thereby ensuring an appropriate space 15. Therefore, the spacer 13 can prevent the flow rate of the cooling gas flowing through the space 15 from decreasing due to the expansion of the battery cell 20. Therefore, the spacer 13 can prevent a decrease in the cooling function of the cooling gas flowing through the space 15 for the battery cell 20 from decreasing. Furthermore, even if the battery cell 20 expands for some reason, the third bar portion 33 and the fourth bar portion 34 can press the case 22 of the battery cell 20, thereby holding the electrode body 23.

[0129] Next, the effects of the third embodiment will be described. (3-1) The first fin portion 46A and the first stopper portion 46B contact the surface 21 of the first battery cell 20A, thereby ensuring an appropriate distance from the surface 21 of the first battery cell 20A. The second fin portion 47A and the second stopper portion 47B contact the surface 21 of the second battery cell 20B, thereby ensuring an appropriate distance from the surface 21 of the second battery cell 20B. Therefore, the spacer 13 can appropriately ensure the distance between adjacent battery cells 20. As a result, heat is appropriately dissipated into the space 15 between the battery cells 20, allowing the battery cells 20 to be appropriately cooled. Furthermore, when the third bar portion 43 and the fourth bar portion 44 are not pressed, the electrode body 23 housed in the battery cell 20 is positioned near the end that is not pressed against the inner wall 22A of the case 22 of the battery cell 20. This allows the spacing between the bar portions 40 to be wider than if the bar portions 40 were located at a position where the inner wall 22A of the case 22 of the battery cell 20 and the electrode body 23 were in contact in an unpressured state, thereby widening the cooling path. Also, the connection positions with the fin portions 45 provided on the third bar portion 43 and the fourth bar portion 44 are located more inward than the ends of the bar portions 40. This allows the third bar portion 43 and the fourth bar portion 44 to press into the case 22 of the battery cell 20 without being obstructed by the fin portions 45, thereby further holding the electrode body 23.

[0130] (3-2) The thickness of the third bar portion 43 and the fourth bar portion 44 corresponds to the distance between the inner wall 22A of the case 22 and the electrode body 23 in the non-pressed state. Therefore, when the spacer 13 is pressed against the battery cell 20, the third bar portion 43 and the fourth bar portion 44 further press into the case 22, enabling the electrode body 23 to be held in place even more.

[0131] (3-3) The first fin portion 46A is provided on the first bar portion 41, and the second fin portion 47A is provided on a second bar portion 42 that is different from the first bar portion 41. Therefore, the first fin portion 46A provided on the first bar portion 41 and the second fin portion 47A provided on the second bar portion 42 contact each other separately with adjacent battery cells 20, thereby ensuring insulation.

[0132] (3-4) The first bar portion 41 is provided with first fin portions 46A that are inclined with respect to the first arrangement direction and first stopper portions 46B that extend in the second arrangement direction, and the second bar portion 42 is provided with second fin portions 47A that are inclined with respect to the second arrangement direction and second stopper portions 47B that extend in the first arrangement direction. As a result, at least the fin portions and stopper portions of each bar portion 40 come into contact with the battery cells 20. This ensures insulation between adjacent battery cells 20.

[0133] (Other embodiments) The above-described embodiments can be modified as follows: The above-described embodiments and the following modifications can be combined with each other within the scope of technical compatibility.

[0134] In the above embodiments, the thickness of the end bar portion is set to a thickness that corresponds to the distance between the inner wall 22A of the case 22 and the electrode body 23 in the unpressed state. However, the thickness of the end bar portion may be set to the same thickness regardless of the distance between the inner wall 22A of the case 22 and the electrode body 23 in the unpressed state.

[0135] In each of the above embodiments, four bar portions are provided, but five or more bar portions may be provided. In the above embodiments, the third bar portion 53 and the fourth bar portion 54 are provided near the ends where the inner wall 22A of the case 22 of the battery cell 20 and the electrode body 23 housed in the battery cell 20 do not come into contact in an unpressured state. However, multiple bar portions may be provided on the top and bottom of the case 22, respectively, near the ends where they do not come into contact in an unpressured state.

[0136] In the above embodiments, the cross-sectional shape of the bar portion is rectangular. However, the cross-sectional shape of the bar portion may be other than rectangular. It may also be shaped to follow the arc shape of the wound electrode body 23. In this way, the electrode body 23 can be more reliably held by the bar portion.

[0137] In the above embodiment, the wound electrode assembly 23 is housed in the case 22. However, as shown in FIG. 12 , stacked electrode assemblies 24 may also be housed in the case 22. In this case, the third bar portion 53 and the fourth bar portion 54 are positioned near the electrode assembly 24 in a portion where no electrode assembly 24 is present. By arranging them in this manner, when the spacer 13 is pressed against the battery cell 20, the third bar portion 53 and the fourth bar portion 54 press into the case 22, thereby ensuring that the electrode assembly 24 is held securely.

[0138] In the above embodiments, the arrangement direction of the bar portions is the vertical direction (Z direction) of the battery cells 20. However, the arrangement direction of the bar portions may also be the width direction (Y direction) of the battery cells 20. Furthermore, the number of bar portions can be changed as appropriate.

[0139] The above embodiments are applicable to any type of battery, such as a nickel-metal hydride secondary battery or a lithium-ion secondary battery, and there is no particular limitation thereon. [Explanation of symbols]

[0140] 10...Battery module 11...Lower case 11A...Floor section 11B...End wall section 13...Spacer 13A…Space forming part 13B…Space forming part 13C…Space forming part 14...End plate 15…Space 20...Battery cell 20A…1st battery cell 20B...2nd battery cell 21...face 22…Case 22A…Inner wall 23...Electrode body 24...Electrode body 30...Bar section 31...First bar section 32...Second bar section 33...Third bar section 34...4th bar section 35...Fin section 36...First fin part 37...Second fin part 38...Third fin part 39...Fourth fin 40...Bar section 41...First bar section 42...Second bar section 43...Third bar section 44...4th bar section 45...Fin section 46A...First fin section 46B...First stopper part 47A...Second fin section 47B...Second stopper part 48...Third fin part 49...Fourth fin 50...Bar section 51...First bar section 52...Second bar section 53...Third bar section 54...4th bar section 55...Fin section 56...First fin part 57...Second fin part 58...Third fin part 59...Fourth fin LA...First fin length LB: Second fin length LC: Third fin length LD...4th fin length LE: 5th fin length LF...6th fin length P...Spacing

Claims

1. A battery module in which a plurality of battery cells and synthetic resin spacers disposed between the battery cells are alternately stacked, The spacer is a plurality of bar portions arranged at intervals along the battery cell; a first fin portion provided on the bar portion, extending toward one of the battery cells at an angle with respect to the arrangement direction of the bar portions, and contacting a surface of the one of the battery cells; a second fin portion that is provided on the bar portion, is inclined with respect to the arrangement direction, extends toward the other battery cell that is different from the one battery cell, and comes into contact with a surface of the other battery cell; the bar portion comprises an end bar portion; an end portion of the electrode body that does not contact the inner wall when the electrode body is not pressed against the inner wall of the battery cell case; the end bar portion is disposed closer to the end of the electrode body than the other bar portions, and only one of the first fin portion and the second fin portion is provided as a fin portion, The connection position of the end bar portion with the fin portion is located inside the end of the end bar portion in a direction perpendicular to the arrangement direction. Battery module.

2. The thickness of the end bar portion is determined according to the distance between the inner wall of the case and the electrode body in an unpressurized state. The battery module according to claim 1 .

3. The first fin portion and the second fin portion are provided on the same bar portion among the plurality of bar portions. The battery module according to claim 1 or 2.

4. the first fin portion is inclined with respect to a first arrangement direction of the arrangement direction, The second fin portion is inclined with respect to a second arrangement direction opposite to the first arrangement direction. The battery module according to claim 3 .

5. the first fin portion is provided on a first bar portion of the plurality of bar portions, The second fin portion is provided on a second bar portion different from the first bar portion among the plurality of bar portions. The battery module according to claim 1 or 2.

6. Two of the first fin portions are provided, one of the first fin portions is inclined with respect to a first arrangement direction of the arrangement direction, the other of the first fin portions is inclined with respect to a second arrangement direction opposite to the first arrangement direction, Two of the second fin portions are provided, one of the second fin portions is inclined with respect to the first arrangement direction, The other of the second fin portions is inclined with respect to the second arrangement direction. The battery module according to claim 5 .

7. the first fin portion is inclined with respect to a first arrangement direction of the arrangement direction, the second fin portion is inclined with respect to the first arrangement direction, a first stopper portion formed on the first bar portion and extending in a second arrangement direction opposite to the first arrangement direction; a second stopper portion formed on the second bar portion and extending in the second arrangement direction; The battery module according to claim 5 .

8. A spacer made of synthetic resin and arranged between a plurality of battery cells that constitute a battery module, A plurality of bar portions arranged at intervals from each other; a first fin portion provided on the bar portion, the first fin portion being formed to extend in a first orthogonal direction perpendicular to the arrangement direction and inclined with respect to a first arrangement direction in which the bar portions are arranged; a second fin portion provided on the bar portion and extending in the first orthogonal direction at an angle with respect to a second arrangement direction opposite to the first arrangement direction; the bar portion comprises an end bar portion; an end portion of the electrode body that does not contact the inner wall when the electrode body is not pressed against the inner wall of the battery cell case; the end bar portion is disposed closer to the end of the electrode body than the other bar portions, and only one of the first fin portion and the second fin portion is provided as a fin portion, The connection position of the end bar portion with the fin portion is located inside the end of the end bar portion in a direction perpendicular to the arrangement direction. Spacer.

9. The thickness of the end bar portion is determined according to the distance between the inner wall of the case and the electrode body in an unpressurized state. The spacer according to claim 8 .

Images