Energy Storage Stack

Abstract

To provide a power storage stack capable of suppressing an increase in a restraint load due to expansion while suppressing a decrease in energy density.SOLUTION: A power storage stack 100 includes: a plurality of power storage cells 10 stacked in a stacking direction; a first end member 21 and a second end member 22 arranged to sandwich the plurality of power storage cells 10 on both sides of the plurality of power storage cells 10 in the stacking direction; and a connecting member 30 connecting the first end member 21 and the second end member 22. The connecting member 30 includes: a first member 31 connected to the first end member 21; a second member 32 connected to the second end member 22; and an elastic member 33 arranged between the first member 31 and the second member 32 and provided to be elastically deformable in a shear direction.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present disclosure relates to an energy storage stack mounted on a vehicle. [Background technology]

[0002] As a conventional electricity storage stack, JP 2019-114477 A (Patent Document 1) discloses a configuration in which a plurality of stacked electricity storage cells are sandwiched between a pair of end plates and the pair of end plates are connected with a tension band (connecting member) to restrain the plurality of electricity storage cells. The tension band is made of metal or fiber-reinforced plastic, and is provided with an elastically deformable uneven portion. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2019-114477 A Summary of the Invention [Problem to be solved by the invention]

[0004] In the case where the tension band that restrains the multiple energy storage cells is made of a highly rigid material such as metal, the restraining load applied to the multiple energy storage cells increases when the multiple energy storage cells expand. In general, it is known to dispose an elastic spacer between adjacent energy storage cells in order to suppress the increase in the restraining load applied during expansion.

[0005] However, when the elastic spacers are arranged as described above, the proportion of the power storage cells that occupy the power storage stack decreases (the total number of power storage cells decreases), which reduces the energy density of the power storage stack.

[0006] The present disclosure has been made in consideration of the above-mentioned problems, and an object of the present disclosure is to provide an energy storage stack that can suppress a decrease in energy density while suppressing an increase in restraining load due to expansion. [Means for solving the problem]

[0007] A power storage stack according to the present disclosure includes a plurality of power storage cells stacked in a stacking direction, a first end member and a second end member arranged on both sides of the plurality of power storage cells in the stacking direction so as to sandwich the plurality of power storage cells therebetween, and a connecting member connecting the first end member and the second end member. The connecting member includes a first member connected to the first end member, a second member connected to the second end member, and an elastic member arranged between the first member and the second member and elastically deformable in a shear direction.

[0008] According to the above configuration, multiple storage cells are stacked without any elastic spacers being placed between the multiple storage cells, so that the proportion of storage cells in the storage stack is increased, and a decrease in energy density can be suppressed.

[0009] In addition, when the stack of multiple energy storage cells expands, the elastic member disposed between the first member connected to the first end member and the second member connected to the second end member elastically deforms in the shear direction, thereby absorbing part of the reaction force from the first end member and the second end member acting on the multiple energy storage cells as the stack expands. As a result, an increase in the restraining load on the multiple energy storage cells as the stack expands can be suppressed.

[0010] In the energy storage stack based on the present disclosure, a cooling path through which cooling air flows to cool the plurality of energy storage cells may be provided between the connecting member and the plurality of energy storage cells.

[0011] According to the above-mentioned configuration, the connecting member can be cooled by the cooling air. Therefore, the elastic member can also be cooled, and thermal deterioration of the elastic member can be suppressed. As a result, a decrease in the restraining load due to deterioration of the elastic member can be suppressed.

[0012] In the power storage stack according to the present disclosure, each of the plurality of power storage cells may be provided with an exhaust valve. In this case, the connecting member may be disposed to face the exhaust valve of each of the plurality of power storage cells.

[0013] According to the above configuration, when the temperature of some of the storage cells rises and high-temperature gas is exhausted from the exhaust valve, heat is transferred to the connecting member by the gas, and the elastic force of the elastic member is reduced or lost. This reduces the restraining load applied to the multiple storage cells by the connecting member, and also reduces the adhesion between adjacent storage cells. As a result, it is possible to suppress thermal chain reaction from the storage cell with the increased temperature to the adjacent storage cells. Effect of the Invention

[0014] According to the present disclosure, it is possible to provide an energy storage stack that can suppress a decrease in energy density and an increase in restraining load associated with expansion. [Brief description of the drawings]

[0015] [Figure 1] 1 is a schematic top view of a power storage stack according to a first embodiment. [Diagram 2] FIG. 2 is a schematic cross-sectional view taken along line II-II shown in FIG. [Diagram 3] 5A and 5B are diagrams illustrating a state in which a stack in which a plurality of power storage cells are stacked expands in the power storage stack according to the first embodiment. [Figure 4] 11 is a schematic top view of a power storage stack according to a second embodiment. FIG. [Diagram 5] FIG. 11 is a schematic top view of a power storage stack according to a third embodiment. [Figure 6]FIG. 11 is a front view of a first end member according to a third embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. In the embodiments described below, the same or common parts are denoted by the same reference characters in the drawings, and the description thereof will not be repeated.

[0017] (Embodiment 1) Fig. 1 is a schematic top view of a power storage stack according to embodiment 1. Fig. 2 is a schematic cross-sectional view taken along line II-II shown in Fig. 1. The power storage stack 100 according to embodiment 1 will be described with reference to Figs. 1 and 2.

[0018] The power storage stack 100 according to the first embodiment is mounted on a hybrid vehicle capable of running using at least one of the power of a motor and an engine, or on an electric vehicle that runs using driving force obtained from electric energy.

[0019] 1 and 2, the electricity storage stack 100 includes a stack 1 in which a plurality of electricity storage cells 10 are stacked in a stacking direction (DR1 direction in the drawings), a first end member 21, a second end member 22, a connecting member 30 (first connecting member), and a connecting member 40 (second connecting member). The electricity storage stack 100 is accommodated in a housing case (not shown).

[0020] The storage cell 10 includes a housing 11, a positive electrode terminal 12, and a negative electrode terminal 13. The housing 11 accommodates a battery element therein. The housing 11 has, for example, a rectangular shape. The housing 11 has an upper surface 11a and a lower surface 11b. The positive electrode terminal 12 and the negative electrode terminal 13 are provided on the upper surface 11a. The positive electrode terminal 12 and the negative electrode terminal 13 are arranged at an interval in the width direction of the storage cell 10 (direction DR2 in FIG. 1) perpendicular to the stacking direction. The positive electrode terminal 12 and the negative electrode terminal 13 are electrically insulated from the upper surface 11a.

[0021] The multiple storage cells 10 are arranged so that adjacent storage cells 10 are in close contact with each other. That is, the multiple storage cells 10 are arranged so that the casings 11 of adjacent storage cells 10 are in contact with each other.

[0022] The multiple storage cells 10 are arranged in the stacking direction, inverted one by one, so that the positive electrode terminals 12 and the negative electrode terminals 13 are arranged alternately. The multiple storage cells 10 are connected in series by alternately electrically connecting the positive electrode terminals 12 and the negative electrode terminals 13 adjacent to each other in the stacking direction at both ends of the storage cells 10 in the width direction.

[0023] The power storage cell 10 is, for example, a secondary battery such as a nickel-metal hydride battery or a lithium-ion battery. The power storage cell 10 is, for example, a secondary battery having a rectangular shape, and may use a liquid electrolyte or a solid electrolyte.

[0024] The first end member 21 is disposed on one end side of the laminate 1 in the stacking direction. The second end member 22 is disposed on the other end side of the laminate 1 in the stacking direction. The first end member 21 and the second end member 22 are disposed so as to sandwich the laminate 1 therebetween.

[0025] The first end member 21 and the second end member 22 are made of, for example, end plates. The first end member 21 and the second end member 22 are made of, for example, a metal member such as stainless steel, a resin member, or the like.

[0026] The first end member 21 and the second end member 22 have a generally plate-like shape. The first end member 21 has an upper surface 21a and a lower surface 21b. Similarly, the second end member 22 has an upper surface 22a and a lower surface 22b. The upper surface 22a of the second end member 22 is located lower than the upper surface 21a of the first end member 21. The lower surface 22b of the second end member 22 is located lower than the lower surface 21b of the first end member 21.

[0027] The connecting member 30 and the connecting member 40 connect the first end member 21 and the second end member 22. As a result, a restraining load acts on the plurality of energy storage cells 10, and the plurality of energy storage cells 10 are restrained.

[0028] The connecting members 30, 40 are arranged side by side in a direction intersecting the stacking direction. Specifically, the connecting members 30, 40 are arranged at intervals in the up-down direction (direction DR3 in FIG. 2). The up-down direction is a direction perpendicular to the stacking direction and the width direction. A plurality of storage cells 10 are arranged between the connecting members 30 and 40.

[0029] The connecting member 30 connects the first end member 21 and the second end member 22 above the multiple energy storage cells 10. More specifically, the connecting member 30 connects an upper surface 21a of the first end member 21 and an upper surface 22a of the second end member 22.

[0030] The connecting member 30 includes a first member 31, a second member 32, and an elastic member 33. The first member 31 and the second member 32 each have, for example, a plate-like shape.

[0031] The first member 31 is connected to the first end member 21. Specifically, an end of the first member 31 located on one side in the stacking direction is connected to the upper surface 21a of the first end member 21. The end may be fastened and fixed to the upper surface 21a by a fastening member or the like, or may be joined to the upper surface 21a by welding, an adhesive, or the like. On the other hand, an end of the first member 31 located on the other side in the stacking direction is not connected to the second end member 22.

[0032] The second member 32 is connected to the second end member 22. Specifically, the end of the second member 32 located on the other side in the stacking direction is connected to the upper surface 22a of the second end member 22. The end may be fastened and fixed to the upper surface 22a by a fastening member or the like, or may be joined to the upper surface 22a by welding, an adhesive, or the like. On the other hand, the end of the second member 32 located on the other side in the stacking direction is not connected to the first end member 21.

[0033] The elastic member 33 is provided so as to be elastically deformable in the shear direction. The elastic member 33 is disposed between the first member 31 and the second member 32. The elastic member 33 is sandwiched between the first member 31 and the second member 32. The elastic member 33 has a substantially plate-like shape.

[0034] The elastic member 33 has a first main surface 33a and a second main surface 33b facing each other in the up-down direction. The first main surface 33a may be joined to a facing surface (first facing surface) of the first member 31 facing the first main surface 33a by welding, an adhesive, or the like. Similarly, the second main surface 33b may be joined to a facing surface (second facing surface) of the second member 32 facing the second main surface 33b by welding, an adhesive, or the like.

[0035] The connecting member 40 connects the first end member 21 and the second end member 22 on the lower side (the other side in the direction DR3 in FIG. 2) of the multiple energy storage cells 10. More specifically, the connecting member 40 connects the lower surface 21b of the first end member 21 and the lower surface 22b of the second end member 22.

[0036] The connecting member 40 includes a first member 41 (third member), a second member 42 (fourth member), and an elastic member 43. An end of the first member 41 on one side in the stacking direction is connected to the lower surface 21b of the first end member 21. On the other hand, an end of the first member 41 on the other side in the stacking direction is not connected to the second end member 22. An end of the second member 42 on the other side in the stacking direction is connected to the lower surface 22b of the second end member 22. On the other hand, an end of the second member 42 on one side in the stacking direction is not connected to the first end member 21. The elastic member 43 is disposed between the first member 41 and the second member 42, and is provided so as to be elastically deformable in the shear direction.

[0037] The shapes, members, arrangements, and other configurations of the first member 41, the second member 42, and the elastic member 43 are almost the same as those of the first member 31, the second member 32, and the elastic member 33 described above, so their explanations will be omitted.

[0038] Fig. 3 is a diagram illustrating a state in which a stack in which a plurality of storage cells are stacked expands in the storage stack according to the first embodiment. Note that in Fig. 3, for the sake of convenience, the size of each storage cell 10 before expansion is shown by a dashed line in schematic form. In other words, the dashed line does not mean that the storage cells 10 are spaced apart from each other before expansion.

[0039] As shown in FIG. 3, when the laminate 1 expands, the first end member 21 and the second end member 22 are pressed by the laminate 1 in directions in which they move away from each other.

[0040] At this time, the first member 31 connected to the first end member 21 side is pulled toward one side in the stacking direction, and the second member 32 connected to the second end member 22 side is pulled toward the other side in the stacking direction. As a result, an elastic biasing force acts toward the other side in the stacking direction as indicated by arrow AR2 on the part of the elastic member 33 located on the first end member 21 side, and an elastic biasing force acts toward one side in the stacking direction as indicated by arrow AR3 on the part of the elastic member 33 located on the second end member 22 side.

[0041] Similarly, the first member 41 connected to the first end member 21 side is pulled toward one side in the stacking direction, and the second member 42 connected to the second end member 22 side is pulled toward the other side in the stacking direction. As a result, an elastic biasing force acts toward the other side in the stacking direction as indicated by arrow AR4 in the portion of the elastic member 43 located on the first end member 21 side, and an elastic biasing force acts toward one side in the stacking direction as indicated by arrow AR5 in the portion of the elastic member 43 located on the second end member 22 side.

[0042] As described above, when an elastic biasing force acts, the elastic members 33, 43 elastically deform in the shear direction, and thus can absorb a part of the reaction force from the first end member 21 and the second end member 22 acting on the multiple energy storage cells 10 (stack 1) as the energy storage cells 10 expand. As a result, an increase in the restraining load on the multiple energy storage cells 10 as the energy storage cells 10 expands can be suppressed.

[0043] In addition, in the energy storage stack 100 of this embodiment, multiple energy storage cells 10 are stacked without any elastic spacers being placed between the multiple energy storage cells 10, so that the proportion of the energy storage cells 10 in the energy storage stack 100 is increased, and a decrease in energy density can be suppressed.

[0044] (Embodiment 2) Fig. 4 is a schematic top view of a power storage stack according to embodiment 2. With reference to Fig. 4, a power storage stack 100A according to embodiment 2 will be described.

[0045] 4, the power storage stack 100A according to the second embodiment is different from the power storage stack 100 according to the first embodiment mainly in that an exhaust valve 14 is provided in the housing 11 of the power storage cell 10. The other configurations are almost the same.

[0046] Exhaust valve 14 is provided on upper surface 11a of housing 11. Exhaust valve 14 is provided, for example, between positive electrode terminal 12 and negative electrode terminal 13. Exhaust valve 14 exhausts high-temperature gas from inside housing 11 to the outside of housing 11 when the pressure inside housing 11 reaches a predetermined level or higher due to gas generated inside housing 11 as a result of heat generation from power storage cell 10.

[0047] The connecting member 30 is disposed so as to face the exhaust valve 14 of each of the plurality of energy storage cells 10. More specifically, the elastic member 33 is disposed so as to cover the plurality of exhaust valves 14 when viewed from above. As a result, when gas is exhausted from the exhaust valves 14, heat is transferred to the connecting member 30, and the elastic force of the elastic member 33 decreases or is lost. As a result, the restraining load applied to the plurality of energy storage cells 10 by the connecting member 30 decreases, and the adhesion between adjacent energy storage cells 10 also decreases. As a result, it is possible to suppress a thermal chain reaction from a storage cell 10 with an increased temperature to an adjacent storage cell 10.

[0048] As described above, in the energy storage stack 100A of embodiment 2, in addition to providing substantially the same effects as the energy storage stack 100 of embodiment 1, the effect of being able to suppress thermal chain reaction to adjacent energy storage cells 10 when the temperature of some of the multiple energy storage cells 10 rises can be obtained.

[0049] (Embodiment 3) Fig. 5 is a schematic top view of a power storage stack according to embodiment 3. With reference to Fig. 5, a power storage stack 100B according to embodiment 3 will be described.

[0050] 5, the energy storage stack 100B according to the third embodiment differs from the energy storage stack 100 according to the first embodiment in that the connecting members 30, 40 are disposed in a different manner, and that cooling paths P1, P2 are provided between the connecting members 30, 40 and the stack 1 (the plurality of energy storage cells 10). The other configurations are substantially the same.

[0051] The first end member 21 has side surfaces 21c and 21d facing each other in the width direction (DR2 direction) of the energy storage cell 10. The side surface 21c is located on one side in the width direction. The side surface 21d is located on the other side in the width direction.

[0052] The second end member 22 has side surfaces 22c and 22d that face each other in the width direction of the energy storage cell 10. The side surface 22c is located on one side in the width direction. The side surface 22d is located on the other side in the width direction.

[0053] In the present embodiment, the upper surface 21a of the first end member 21 and the upper surface 22a of the second end member 22 may be located at the same height position. On the other hand, the side surface 22c of the second end member 22 is located on the other side in the width direction than the side surface 21c of the first end member 21. Similarly, the side surface 22d of the second end member 22 is located on the other side in the width direction than the side surface 21d of the first end member 21.

[0054] The connecting members 30, 40 are arranged side by side in a direction intersecting the stacking direction. Specifically, the connecting members 30, 40 are arranged at intervals in the width direction. A plurality of energy storage cells 10 are arranged between the connecting members 30 and 40.

[0055] The connecting member 30 connects the first end member 21 and the second end member 22 on one side in the width direction. More specifically, the connecting member 30 connects the side surface 21c of the first end member 21 and the side surface 22c of the second end member 22.

[0056] Specifically, almost similar to the first embodiment, an end of the first member 31 located on one side in the stacking direction is connected to a side surface 21c of the first end member 21, and an end of the second member 32 located on the other side in the stacking direction is connected to a side surface 22c of the second end member 22. The elastic member 33 is disposed between the first member 31 and the second member 32, and is provided so as to be elastically deformable in the shear direction. The end of the first member 31 located on the other side in the stacking direction is not connected to the second end member 22, and the end of the second member 32 located on one side in the stacking direction is not connected to the first end member 21.

[0057] The connecting member 40 connects the first end member 21 and the second end member 22 on the other side in the width direction. More specifically, the connecting member 30 connects the side surface 21c of the first end member 21 and the side surface 22c of the second end member 22.

[0058] Specifically, in a manner similar to that described above, an end of the first member 41 located on one side in the stacking direction is connected to a side surface 21d of the first end member 21, and an end of the second member 42 located on the other side in the stacking direction is connected to a side surface 22d of the second end member 22. The elastic member 43 is disposed between the first member 41 and the second member 42, and is provided so as to be elastically deformable in the shear direction. The end of the first member 41 located on the other side in the stacking direction is not connected to the second end member 22, and the end of the second member 42 located on one side in the stacking direction is not connected to the first end member 21.

[0059] Between the connecting members 30 and the plurality of energy storage cells 10, cooling paths P1 and P2 are provided through which cooling air flows.

[0060] Specifically, the cooling path P1 is defined by the space between a side surface 1c of the laminate 1 located on one side in the width direction and the connecting member 30. The cooling path P2 is defined by the space between a side surface 1d of the laminate 1 located on the other side in the width direction and the connecting member 40.

[0061] The cooling air is introduced, for example, from the first end member 21 side and discharged from the second end member 22 side. Specifically, for example, the cooling air flows in the cooling path P1 as shown by the arrow AR6, and the cooling air flows in the cooling path P2 as shown by the arrow AR7. Note that the flow direction of the cooling air may be the opposite direction to that described above.

[0062] Fig. 6 is a front view of a first end member according to embodiment 3. As shown in Fig. 6, the first end member 21 is provided with a plurality of inlet holes 21h communicating with the cooling paths P1 and P2 so that cooling air can be introduced into the cooling paths P1 and P2. Similarly, the second end member 22 is provided with a plurality of outlet holes communicating with the cooling paths P1 and P2.

[0063] The cooling air flows through the cooling paths P1, P2, thereby cooling the connecting members 30, 40. Therefore, the elastic members 33, 43 can also be cooled, and thermal deterioration of the elastic members 33, 43 can be suppressed. This makes it possible to suppress a decrease in the restraining load due to deterioration of the elastic members 33, 43. In other words, the durability of the connecting members 30, 40 can be improved.

[0064] In the energy storage stack 100B of embodiment 3 configured as described above, by providing the connecting members 30, 40, it is possible to obtain substantially the same effects as the energy storage stack 100 of embodiment 1, and also to obtain the effect of suppressing the decrease in the restraining load due to deterioration of the elastic member, as described above.

[0065] (Other variations) In the above-mentioned first embodiment, the connecting member 30 connects the upper surface 21a of the first end member 21 and the upper surface 22a of the second end member 22, and the connecting member 40 connects the lower surface 21b of the first end member 21 and the lower surface 22b of the second end member 22, but this is not limiting. For example, as in the third embodiment, the connecting member 30 may connect the side surface 21c of the first end member 21 and the side surface 22c of the second end member 22, and the connecting member 40 may connect the side surface 21d of the first end member 21 and the side surface 22d of the second end member 22.

[0066] Furthermore, in the above-mentioned embodiment 2, as long as cooling paths P1, P2 are formed between the connecting members 30, 40 and the stack 1, the connecting member 30 may connect the upper surface 21a of the first end member 21 and the upper surface 22a of the second end member 22, and the connecting member 40 may connect the lower surface 21b of the first end member 21 and the lower surface 22b of the second end member 22.

[0067] The embodiments disclosed herein are illustrative and not restrictive in all respects. The scope of the present invention is defined by the claims, and includes all modifications within the meaning and scope of the claims. [Explanation of symbols]

[0068] 1 laminate, 1c, 1d side, 10 energy storage cell, 11 housing, 11a upper surface, 11b lower surface, 12 positive electrode terminal, 13 negative electrode terminal, 14 exhaust valve, 21 first end member, 21a upper surface, 21b lower surface, 21c, 21d side, 21h introduction hole, 22 second end member, 22a upper surface, 22b lower surface, 22c, 22d side, 30 connecting member, 31 first member, 32 second member, 33 elastic member, 33a first main surface, 33b second main surface, 40 connecting member, 41 first member, 42 second member, 43 elastic member, 100, 100A, 100B energy storage stack.

Claims

1. A plurality of storage cells stacked in a stacking direction; a first end member and a second end member arranged on either side of the plurality of storage cells in the stacking direction so as to sandwich the plurality of storage cells; a connecting member connecting the first end member and the second end member, The connecting member includes a first member connected to the first end member, a second member connected to the second end member, and an elastic member arranged between the first member and the second member and capable of elastically deforming in a shear direction.

2. The power storage stack according to claim 1 , further comprising a cooling path provided between the connecting member and the plurality of power storage cells, through which cooling air flows to cool the plurality of power storage cells.

3. Each of the plurality of power storage cells is provided with an exhaust valve, The electricity storage stack according to claim 1 , wherein the connecting member is disposed so as to face the exhaust valve of each of the plurality of electricity storage cells.

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