Power storage module

Abstract

To provide a power storage module including a plate member capable of fixing a plurality of power storage cells that are stacked, while the increase in temperature near electrode terminals of the power storage cells is suppressed.SOLUTION: A power storage module includes a plurality of power storage cells that are stacked in a first direction, and at least one plate member that is adjacent in the first direction to at least one power storage cell among the plurality of power storage cells. The power storage cell includes a pair of electrode terminals disposed at cell end parts on both sides in a second direction that is orthogonal to the first direction. The plate member includes a plate central part projecting toward the adjacent power storage cell on the central side in the second direction, a plate end part that is depressed in the first direction relative to the plate central part on both sides in the second direction, a groove disposed near the electrode terminal and formed on a surface of the plate end part that faces the adjacent power storage cell, and a thermally conductive adhesive member accommodated in the groove so as to be in contact with the adjacent power storage cell.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present disclosure relates to an energy storage module, and more particularly to an energy storage module having a plurality of energy storage cells stacked in a first direction. [Background technology]

[0002] In recent years, vehicles that move using motor torque generated by a motor, such as electric vehicles and hybrid vehicles, have become increasingly popular. Such vehicles are equipped with a power storage module that stores power to supply to the motor.

[0003] As an example of an energy storage module, Patent Document 1 discloses a battery module including a cell assembly having a plurality of battery cells stacked in the left-right direction and a module housing that houses the cell assembly. Patent Document 1 describes that the module housing includes an upper plate that covers the upper part of the cell assembly, a left plate that covers the left side of the cell assembly, a right plate that covers the right side of the cell assembly, and a lower plate that covers the lower part of the cell assembly, and that at least one of the left plate and the right plate has a support portion that protrudes from an inner surface facing the plurality of battery cells toward the cell assembly so as to pressurize at least a portion of the cell assembly that has relatively little volumetric expansion. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 2023-523207 Summary of the Invention [Problem to be solved by the invention]

[0005] Incidentally, each of the multiple storage cells (battery cells) included in the energy storage module includes positive and negative electrode terminals. In an energy storage module having multiple stacked storage cells, current tends to concentrate near the electrode terminals of the storage cells during charging and discharging. Therefore, the technology described in Patent Document 1 has a problem in that the temperature tends to rise near the electrode terminals of the multiple stacked storage cells. This problem becomes particularly noticeable in long energy storage modules in which a large number of storage cells are stacked.

[0006] The present disclosure has been made to solve such problems, and aims to provide a storage module having a plate member that can fix storage cells while suppressing a rise in temperature near the electrode terminals of multiple stacked storage cells. [Means for solving the problem]

[0007] A storage module according to one embodiment includes a plurality of storage cells stacked in a first direction and at least one plate member adjacent in the first direction to at least one of the plurality of storage cells, wherein the storage cell includes a pair of electrode terminals arranged at both ends of the cell in a second direction perpendicular to the first direction, and the plate member includes a plate central portion protruding toward the adjacent storage cell at the center in the second direction, plate ends recessed in the first direction relative to the plate central portion on both sides of the second direction, a groove arranged near the electrode terminal and formed on the surface of the plate end facing the adjacent storage cell, and a thermally conductive adhesive member housed in the groove so as to contact the adjacent storage cell. [Effects of the Invention]

[0008] The present disclosure makes it possible to provide an energy storage module having a plate member capable of fixing energy storage cells while suppressing a rise in temperature near the electrode terminals of a plurality of stacked energy storage cells. [Brief explanation of the drawings]

[0009] [Figure 1]1 is a side view showing a part of the electricity storage module according to the first embodiment. [Figure 2] FIG. 2 is a top view showing a part of the power storage module according to the first embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0010] Embodiment 1 Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. However, the present disclosure is not limited to the following embodiments. Furthermore, for clarity of explanation, the following description and drawings have been simplified as appropriate. What is shown in the drawings is only a part of the whole, and in reality, many other configurations not shown are included. In the following description, the same or equivalent elements are given the same reference numerals, and redundant explanations will be omitted.

[0011] An energy storage module 1 according to this embodiment will be described with reference to Fig. 1 and Fig. 2. Fig. 1 is a side view showing a part of the energy storage module according to the first embodiment. Fig. 2 is a top view showing a part of the energy storage module according to the first embodiment.

[0012] The energy storage module 1 shown in Figures 1 and 2 is mounted on an electric vehicle (hereinafter sometimes referred to as a vehicle), such as a hybrid vehicle that can run using the power of at least one of a motor and an engine, or an electric car that runs using driving force obtained from electrical energy.

[0013] 1 and 2, the energy storage module 1 has a stack 11 of a plurality of energy storage cells 10 stacked in a first direction (DR1), and a housing 30 that accommodates the stack 11. Note that the first direction is parallel to, for example, the width direction of the vehicle when the energy storage module 1 is mounted on the vehicle.

[0014] 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 may use a liquid electrolyte or a solid electrolyte. The power storage cell 10 may also be a unit capacitor configured to be able to store electricity.

[0015] The energy storage cell 10 has a power generating element, a cell case 12, and a pair of electrode terminals 13. The power generating element is configured by stacking positive and negative electrode plates with a separator interposed therebetween. The cell case 12 is a housing that houses the battery element. The cell case 12 has, for example, a substantially rectangular parallelepiped shape that is flattened in a first direction. The cell case 12 is formed from a conductive material such as a metal (for example, aluminum or an aluminum alloy).

[0016] The cell case 12 has a pair of main surface portions 12a facing each other in a first direction, a pair of side surface portions 12b facing each other in a second direction (DR2) perpendicular to the first direction, an upper surface portion 12c, and a lower surface portion 12d. The upper surface portion 12c and the lower surface portion 12d face each other in a vertical direction (DR3) perpendicular to the first and second directions. A power generating element is accommodated together with an electrolyte in the internal space of the cell case 12 formed by the pair of main surface portions 12a, the pair of side surface portions 12b, the upper surface portion 12c, and the lower surface portion 12d. Note that the second direction is, for example, parallel to the front-to-rear direction of the vehicle when the energy storage module 1 is mounted on the vehicle.

[0017] The pair of electrode terminals 13 are arranged at cell end portions 10a on both sides in the first direction of each storage cell 10. The pair of electrode terminals 13 are attached to the top surface portion 12c. The pair of electrode terminals 13 protrude upward from the top surface portion 12c. However, the pair of electrode terminals 13 may also be attached to the pair of side surface portions 12b so as to protrude outward in the second direction from the pair of side surface portions 12b.

[0018] One of the pair of electrode terminals 13 is a positive terminal connected to a positive electrode plate. The other of the pair of electrode terminals 13 is a negative terminal connected to a negative electrode plate. The electrode terminals 13 of the storage cells 10 adjacent to each other in the first direction are connected to each other by a bus bar. The multiple storage cells 10 are stacked, for example, with their orientations alternately reversed so that the positive terminals and negative terminals of the storage cells 10 adjacent to each other in the first direction are adjacent to each other. In this case, the bus bar connects the positive terminal of one storage cell 10 to the negative terminal of the adjacent storage cell 10. This connects the multiple storage cells 10 in series.

[0019] 1 and 2 show one laminate 11 housed in the housing 30. The housing 30 may house one laminate 11 in this manner, or may house two or more laminates 11. When the housing 30 houses multiple laminates 11, the multiple laminates 11 housed in the housing 30 may be arranged so as to line up along the second direction.

[0020] The housing 30 is made of a conductive material such as metal. The housing 30 has a bottom member 31 and at least one plate member 32. As shown in FIG. 1, the bottom member 31 is a substantially rectangular flat member extending in the first direction and the second direction so as to cover the lower surface of the laminate 11. The bottom member 31 is disposed below the laminate 11. The laminate 11 is placed on the bottom member 31 with a thermally conductive layer 40 interposed therebetween. Note that FIG. 1 shows a cross-sectional view of the housing 30 as viewed from the second direction.

[0021] The thermally conductive layer 40 also functions as an adhesive layer, adhesively fixing the stack 11 to the bottom member 31. The thermally conductive layer 40 keeps the stack 11 in thermal contact with the inner surface 31a of the bottom member 31.

[0022] The thermally conductive layer 40 is made of a thermally conductive resin material. Examples of the resin material that can be used to form the thermally conductive layer 40 include adhesives containing silicone resin, acrylic resin, urethane resin, and epoxy resin.

[0023] Thus, in a storage module 1 having a plurality of stacked storage cells 10, current tends to concentrate near the electrode terminals 13 of the storage cells 10 during charging and discharging. Therefore, Joule heat tends to increase the temperature near the electrode terminals 13 of the stacked storage cells 10. This phenomenon becomes particularly noticeable in a long storage module 1 in which a large number of storage cells 10 are stacked.

[0024] Therefore, the energy storage module 1 according to this embodiment has a plate member 32 that can cool the vicinity of the electrode terminals 13 of the adjacent energy storage cells 10.

[0025] As shown in FIGS. 1 and 2 , the plate member 32 is arranged on one end side of the stack body 11 in the first direction. The plate member 32 can be arranged not only on one end side of the stack body 11 in the first direction but also on the other end side. In this embodiment, the energy storage module 1 has a pair of plate members 32, including a plate member 32 arranged on one end side of the stack body 11 and a plate member 32 arranged on the other end side of the stack body 11. In this way, the pair of plate members 32 arranged on both ends of the stack body 11 in the first direction sandwich the stack body 11 from both sides in the first direction. The pair of plate members 32 apply a load to the stack body 11 that restrains the stack body 11 sandwiched between them.

[0026] 1 and 2 show the plate member 32 of the pair of plate members 32 arranged on one end side of the laminate 11. In this embodiment, the plate member 32 arranged on the other end side of the laminate 11 is configured symmetrically in the first direction with the plate member 32 arranged on one end side of the laminate 11. Therefore, in the following description, the configuration of the plate member 32 arranged on one end side of the laminate 11 will be described in detail, and a description of the plate member 32 arranged on the other side of the laminate 11 will be omitted. However, the pair of plate members 32 are not limited to being configured symmetrically in the first direction, and for example, the plate member 32 arranged on the other end side of the laminate 11 may be replaced with another member.

[0027] The plate member 32 is a substantially rectangular flat member extending in the first direction and in the up-down direction so as to cover the main surface portion 12a arranged on one side in the first direction of the end storage cell 10. Here, the "end storage cell 10" refers to the storage cell 10 arranged on one end of the stack 11 on one side in the first direction. The plate member 32 extends upward from the end of the bottom member 31 on one side in the first direction. The plate member 32 may be connected to the bottom member 31 or may be formed integrally with the bottom member 31.

[0028] The plate member 32 has a first main surface 33, a second main surface 34, a pair of grooves 35, and an adhesive member 36. The first main surface 33 is the surface of the plate member 32 that faces the energy storage cell 10 adjacent to the plate member 32. The second main surface 34 is the surface of the plate member 32 opposite to the first main surface 33.

[0029] As shown in FIG. 2 , a pair of grooves 35 are formed in the first main surfaces 33 of the plate ends 32a on both sides in the second direction, which is the width direction of the plate member 32. The pair of grooves 35 are provided at positions corresponding to the cell ends 10a on both sides. That is, the grooves 35 are arranged near the electrode terminals 13. The groove 35 arranged on one side in the second direction is arranged near the electrode terminal 13 arranged on one side in the second direction and is formed on the first main surface 33 of the plate end 32a arranged on one side in the second direction. The groove 35 arranged on the other side in the second direction is arranged near the electrode terminal 13 arranged on the other side in the second direction and is formed on the first main surface 33 of the plate end 32a arranged on the other side in the second direction. The grooves 35 are recessed from the first main surface 33 toward the second main surface 34. That is, the grooves 35 are recessed on the side opposite to the energy storage cell 10 adjacent to the plate member 32 in which the grooves 35 are formed. The grooves 35 extend in the vertical direction. The groove 35 accommodates an adhesive member 36 .

[0030] The adhesive member 36 is made of a thermally conductive resin material, such as an adhesive containing a silicone resin, an acrylic resin, a urethane resin, or an epoxy resin.

[0031] The adhesive member 36 is housed in the groove 35 so as to be in contact with the energy storage cell 10 adjacent to the plate member 32. The adhesive member 36 housed in the groove 35 adhesively fixes the energy storage cell 10 adjacent to the plate member 32 to the plate member 32. The energy storage cell 10 adjacent to the plate member 32 is in thermal contact with the first main surface 33 of the plate member 32 by the adhesive member 36. In this embodiment, the energy storage cell 10 adjacent to the plate member 32 is an end storage cell 10.

[0032] The adhesive member 36 is housed in the groove 35, and therefore the adhesive strength can be increased by the anchor effect. The adhesive member 36 is also attached to the vicinity of the electrode terminal 13 of the energy storage cell 10 adjacent to the plate member 32. The adhesive member 36 has thermal conductivity, and therefore can cool the vicinity of the electrode terminal 13 of the energy storage cell 10 adjacent to the plate member 32.

[0033] Here, when the electrode terminals 13 are attached to the upper surface portion 12c, the grooves 35 preferably extend in the vertical direction up to the upper end of the plate member 32. This increases the contact area between the adhesive member 36 and the energy storage cells 10, and can further enhance the effect of cooling the vicinity of the electrode terminals 13 of the energy storage cells 10 adjacent to the plate member 32. From the viewpoint of further improving the cooling effect, it is particularly preferable that the grooves 35 extend from the upper end to the lower end of the plate member 32.

[0034] The adhesive member 36 can be formed by injecting a molten adhesive into the groove 35. This prevents the adhesive member 36 from dripping when it is formed, and allows the adhesive member 36 to be formed with a uniform thickness (thickness along the first direction) up to the upper end or from the upper end to the lower end of the plate member 32. The adhesive member 36 with a uniform thickness adheres favorably to the vicinity of the electrode terminal 13 of the energy storage cell 10 adjacent to the plate member 32, thereby enhancing the effect of the adhesive member 36 in cooling the vicinity of the electrode terminal 13 of the energy storage cell 10 adjacent to the plate member 32.

[0035] Furthermore, it is preferable that at least a portion of the groove surface 35a of the groove 35 has an uneven shape. The uneven shape of the groove surface 35a increases the adhesion area between the adhesive member 36 housed in the groove 35 and the plate member 32, thereby improving the adhesive strength. From the viewpoint of further improving the adhesive strength, the convex portion of the uneven groove surface 35a may be formed, for example, so that the cross-sectional area gradually decreases toward the tip. Preferred shapes of the convex portion include tapered shapes such as a truncated cone shape or a truncated pyramid shape.

[0036] The plate member 32 has plate end portions 32a on both sides in the second direction and a plate central portion 32b sandwiched between the plate end portions 32a from both sides in the second direction. The plate central portion 32b is arranged on the center side of the plate member 32 in the second direction. The plate central portion 32b is provided at a position facing the cell central portion 10b in the second direction of the adjacent energy storage cell 10. The plate central portion 32b supports the adjacent energy storage cell 10 and applies a load in the second direction to the stack 11.

[0037] The thickness of the plate central portion 32b in the first direction is formed to be greater than the thickness of the plate end portions 32a on both sides in the first direction. That is, the plate member 32 includes the plate central portion 32b that protrudes toward the energy storage cells 10 in the first direction at the center side in the second direction, and the plate end portions 32a that are recessed in the first direction relative to the plate central portion 32b on both sides in the second direction.

[0038] The plate central portion 32b presses against the cell central portions 10b of the adjacent energy storage cells 10, and therefore, the load can be applied more uniformly to the plurality of energy storage cells 10 that make up the stack 11. Furthermore, by making the thickness of the plate central portion 32b in the plate member 32 relatively thick, the strength of the plate central portion 32b that receives the reaction force from the energy storage cells 10 can be improved.

[0039] In this way, the plate member 32 can apply a load more uniformly to the plurality of energy storage cells 10 constituting the stack 11 by the plate center portion 32b while fixing the stack 11 with the adhesive member 36 housed in the groove 35. When the load is applied uniformly to the plurality of energy storage cells 10, an increase in the internal resistance of the energy storage cells 10 caused by unevenness in the distance between the electrodes or unevenness in the concentration of the electrolyte is suppressed.

[0040] As described above, the energy storage module 1 according to this embodiment includes a plurality of energy storage cells 10 stacked in a first direction, and at least one plate member 32 adjacent in the first direction to at least one of the plurality of energy storage cells 10. The energy storage cell 10 includes a pair of electrode terminals 13 arranged at cell end portions 10a on both sides in a second direction perpendicular to the first direction. The plate member 32 includes a plate central portion 32b that protrudes toward the adjacent energy storage cell 10 at the center in the second direction, plate end portions 32a that are recessed in the first direction relative to the plate central portion 32b on both sides in the second direction, grooves 35 that are arranged near the electrode terminals 13 and formed on the surfaces of the plate end portions 32a that face the adjacent energy storage cell 10, and a thermally conductive adhesive member 36 accommodated in the groove 35 so as to contact the adjacent energy storage cell 10.

[0041] According to this embodiment, it is possible to provide a storage module 1 having plate members 32 capable of fixing the storage cells 10 while suppressing a rise in temperature near the electrode terminals 13 of the stacked storage cells 10.

[0042] The present disclosure is not limited to the above-described embodiment and can be modified as appropriate without departing from the spirit of the present disclosure. For example, in the above-described embodiment, the plate member 32 is adjacent to the end storage cell 10. However, the plate member 32 may be disposed between at least one of the adjacent storage cells 10 among the plurality of storage cells 10, so that the plate member 32 is adjacent to the storage cell 10 that is not at the end. By disposing the plate member 32 between the adjacent storage cells 10, the vicinity of the electrode terminal 13 of the storage cell 10 disposed at the center of the stack 11 in the first direction can be cooled, thereby further enhancing the cooling effect. The plate member 32 disposed between the adjacent storage cells 10 also functions as a partition member that separates the adjacent storage cells 10.

[0043] Furthermore, the plate member 32 arranged between adjacent energy storage cells 10 may have grooves 35 accommodating adhesive members 36 formed not only on the first main surface 33 but also on the second main surface 34. When the plate member 32 is arranged between adjacent energy storage cells 10, the plate member 32 adjacent to the end energy storage cell 10 may be omitted. [Explanation of symbols]

[0044] 1. Energy storage module 10: Energy storage cell; 10a: Cell edge; 10b: Cell center 11 Laminate 12 Cell case 12a Main surface part 12b Side part 12c Top surface part 12d Bottom surface part 13 Electrode terminal 30 Housing 31 Bottom member 31a Inner surface 32 Plate member 32a Plate end 32b Plate center 33 First principal surface 34 Second principal surface 35 Groove 35a Groove surface 36 Adhesive material 40 Thermal Conduction Layer

Claims

[Claim 1] a plurality of storage cells stacked in a first direction; at least one plate member adjacent to at least one storage cell of the plurality of storage cells in the first direction; The storage cell is a pair of electrode terminals disposed at cell ends on both sides in a second direction perpendicular to the first direction; The plate member is a plate central portion protruding toward the adjacent energy storage cell at a central side in the second direction; plate ends recessed in the first direction from the plate center on both sides in the second direction; a groove disposed near the electrode terminal and formed on a surface of the plate end facing the adjacent energy storage cell; a thermally conductive adhesive member accommodated in the groove so as to be in contact with adjacent ones of the power storage cells; A storage module including:

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