Restraint member and power storage device

Abstract

To provide a binding member and a power storage device capable of promoting the discharge of gas generated within a power storage module.SOLUTION: A binding member 4 includes a pair of holding portions 10, a plurality of pressurizing portions 20, and a pair of pressing portions 30. Each of the pressurizing portions 20 has a shape in which a dimension in a third direction perpendicular to both the first direction and the second direction is longer than a dimension in the first direction and a dimension in the second direction, and is in contact with the holding portion 10 and the pressing portion 30. Each of the holding portions 10 includes a pressurizing region 10P that overlaps each of the pressurizing portions 20 in the first direction, and a low pressurizing region 10γ that does not overlap the pressurizing portion 20 in the first direction.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present disclosure relates to a restraining member and an electricity storage device. [Background technology]

[0002] For example, Japanese Patent Application Laid-Open No. 2021-82407 discloses a battery module including a stack of multiple battery cells and a pressure mechanism that applies pressure to the stack in the stacking direction. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2021-82407 Summary of the Invention [Problem to be solved by the invention]

[0004] The battery module described in JP 2021-82407 A leaves room for improvement in the discharge of gas generated within the storage cells.

[0005] An object of the present disclosure is to provide a restraint member and an electricity storage device that can promote the discharge of gas generated within an electricity storage module. [Means for solving the problem]

[0006] According to one aspect of the present disclosure, the restraint member includes a pair of clamping portions that clamp a storage module including a plurality of storage cells stacked in a first direction from both sides in the first direction; a plurality of pressure applying portions arranged outside each of the pair of clamping portions in the first direction and spaced apart in a second direction perpendicular to the first direction; and a pair of pressing portions that are arranged outside the plurality of pressure applying portions in the first direction and press the plurality of pressure applying portions toward each of the pair of clamping portions, wherein each of the plurality of pressure applying portions has a dimension in a third direction perpendicular to both the first direction and the second direction that is longer than its dimension in the first direction and its dimension in the second direction, and is in contact with the clamping portion and the pressing portion, and each of the pair of clamping portions includes a pressure applying region that overlaps with each of the pressure applying portions in the first direction and a low pressure applying region that does not overlap with the pressure applying portions in the first direction.

[0007] Also, an energy storage device according to one aspect of the present disclosure is an energy storage device including the restraining member and the energy storage module, wherein the energy storage module is restrained by the restraining member from both sides in the first direction. [Effects of the Invention]

[0008] According to the present disclosure, it is possible to provide a restraint member and an electricity storage device that can promote the discharge of gas generated in an electricity storage module. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a perspective view schematically illustrating an electric storage device including a restraint member according to an embodiment of the present disclosure. [Figure 2] FIG. 2 is a cross-sectional view taken along line II-II in FIG. [Figure 3] FIG. 2 is a diagram schematically showing the behavior of gas generated in a power storage cell. [Figure 4] FIG. 10 is a cross-sectional view schematically showing a modified example of the restraining member. [Figure 5] FIG. 10 is a cross-sectional view schematically showing a modified example of the restraining member. [Figure 6]FIG. 10 is a perspective view schematically showing a modified example of the pressure unit. [Figure 7] FIG. 10 is a cross-sectional view schematically showing a modified example of the pressure unit. DETAILED DESCRIPTION OF THE INVENTION

[0010] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] The present disclosure will be described with reference to the accompanying drawings, in which the same or corresponding elements are designated by the same reference numerals.

[0011] Fig. 1 is a perspective view schematically illustrating an energy storage device including a restraint member according to an embodiment of the present disclosure. Fig. 2 is a cross-sectional view taken along line II-II in Fig. 1. As shown in Figs. 1 and 2, the energy storage device 1 includes an energy storage module 2 and a restraint member 4.

[0012] The energy storage module 2 includes a plurality of energy storage cells 2a (see FIG. 3) stacked in a first direction. As shown in the enlarged view of a portion of the energy storage cell 2a in FIG. 3, the energy storage module 2 may be, for example, a bipolar battery in which a plurality of electrodes, including a bipolar electrode in which a positive electrode layer 102 is formed on one side of a current collector 101 and a negative electrode layer 103 is formed on the other side, are alternately stacked with separators 110 in the first direction, or may be a monopolar battery. The energy storage module 2 is formed, for example, in a rectangular shape with one side measuring 0.2 m or more in plan view.

[0013] The restraining member 4 is suitable for use in restraining the energy storage module 2. The restraining member 4 is a member that restrains the energy storage module 2 from both sides in the first direction. As shown in FIG. 1 , the restraining member 4 includes a pair of clamping portions 10, a plurality of pressure applying portions 20, a pair of pressing portions 30, and a tightening member 40.

[0014] The pair of clamping parts 10 sandwich the energy storage module 2 including the plurality of energy storage cells 2a from both sides in the first direction. Each clamping part 10 is formed in a flat plate shape. The outer shape of each clamping part 10 in a plan view is larger than the outer shape of the energy storage module 2 in a plan view. The thickness of each clamping part 10 is set to, for example, 10 mm or less. Each clamping part 10 is made of aluminum or the like.

[0015] Each pressure unit 20 is disposed on the outside of each of the pair of clamping units 10 in the first direction. As shown in FIG. 2 , the multiple pressure units 20 disposed on the outside of one clamping unit 10 and the multiple pressure units 20 disposed on the outside of the other clamping unit 10 face each other in the first direction, sandwiching the energy storage module 2 therebetween. Each pressure unit 20 is in contact with the outer surface 10S of the clamping unit 10 in the first direction. The pressure units 20 are disposed so as to be spaced apart in a second direction perpendicular to the first direction. The pressure units 20 are preferably disposed so as to be equally spaced apart in the second direction. Each pressure unit 20 has a shape extending in a third direction perpendicular to both the first and second directions. Specifically, the dimension of each pressure unit 20 in the third direction is larger than the dimension of each pressure unit 20 in the first direction and the dimension of each pressure unit 20 in the second direction. In this embodiment, each pressure unit 20 is formed from a so-called square pipe, which is a hollow cylindrical square tube formed from a strip-shaped plate material with a uniform thickness. That is, each pressure member 20 is formed in a rectangular tubular shape, extending such that its longitudinal direction coincides with the third direction and having a rectangular cross section perpendicular to the third direction. Each pressure member 20 is made of aluminum or the like.

[0016] The outer shape of the region in which the multiple pressure applying units 20 are arranged in a plan view (hereinafter referred to as the "pressure applying region") can be set appropriately depending on the size of the energy storage module 2. The outer shape of the pressure applying region is preferably formed to be the same as or larger than the outer shape of the energy storage module 2 in a plan view. For example, if the outer shape of the energy storage module 2 in a plan view is a rectangle with a side of 0.2 m, the outer shape of the pressure applying region is formed to be a rectangle with a side of 0.2 m or more. In this embodiment, the length of each pressure applying unit 20 in the third direction is set to be equal to or greater than the length of the energy storage module 2 in the third direction. Furthermore, the pressure applying unit 20 that is arranged outermost in the second direction among the multiple pressure applying units 20 is arranged in contact with the end of the energy storage module 2, and its outer surface 21S in the second direction is flush with or positioned outer than the outer surface 2S of the energy storage module 2 in the second direction.

[0017] Each pressure applying portion 20 has a pair of high pressure applying portions 21, a medium pressure applying portion 22, and a connecting portion 23.

[0018] The high pressure sections 21 face each other at intervals in the second direction. In this embodiment, each high pressure section 21 is formed of a flat plate that is perpendicular to the second direction. Each high pressure section 21 contacts the outer surface 10S of the clamping section 10 in the first direction.

[0019] The intermediate pressure section 22 connects the pair of high pressure sections 21. In this embodiment, the intermediate pressure section 22 is configured as a flat plate section that is perpendicular to the first direction. The intermediate pressure section 22 is in contact with the outer surface 10S of the clamping section 10 in the first direction.

[0020] The connecting portion 23 connects the outer ends in the first direction of the pair of high pressure portions 21. In this embodiment, the connecting portion 23 is formed of a flat plate portion that is perpendicular to the first direction.

[0021] The pair of pressing units 30 presses the multiple pressure units 20 toward each of the pair of clamping units 10. Each pressing unit 30 is disposed outside the multiple pressure units 20 in the first direction. Each pressing unit 30 is formed in a flat plate shape. The connecting unit 23 of each pressing unit 20 contacts the inner surface 30S of the pressing unit 30 in the first direction. The outer shape of each pressing unit 30 in a planar view is larger than the outer shape of the energy storage module 2 in a planar view. Furthermore, the outer shape of each pressing unit 30 in a planar view is preferably formed to be the same as or larger than the pressure region in a planar view. The thickness of each pressing unit 30 may be, for example, 10 mm or less. The thickness or Young's modulus of each pressing unit 30 may be larger than the thickness or Young's modulus of each clamping unit 10 so that the bending rigidity of each pressing unit 30 is higher than the bending rigidity of each clamping unit 10. Each pressing unit 30 is made of aluminum or the like.

[0022] The tightening members 40 tighten the pair of pressing portions 30 from both sides in the first direction. The tightening members 40 tighten the pair of pressing portions 30 so that a pressing force of 10 N to 400 N acts on each pressing portion 30. The tightening members 40 are attached to the ends of each pressing portion 30 in the third direction. The tightening members 40 are configured, for example, as bands. Note that a plurality of tightening members 40 may be provided at the ends of each pressing portion 30 in the third direction, as well as at intermediate portions of each pressing portion 30 in the third direction. The tightening members 40 may also be configured to tighten the pair of pressing portions 30 from both sides in the first direction using fastening members such as bolts. As shown in FIGS. 2 and 3 , a pressurized region 10P and a low-pressure region 10γ are formed in each clamping portion 10 by tightening with the tightening members 40.

[0023] The pressure region 10P is an area that overlaps with each pressure member 20 in the first direction. The pressure region 10P is an area that receives pressure from each pressure member 20. The pressure region 10P has a pair of high pressure regions 10α and a medium pressure region 10β.

[0024] Each high pressure region 10α is a region that overlaps with each high pressure portion 21 in the first direction and receives pressure from each high pressure portion 21.

[0025] The medium pressure region 10β is a region that overlaps with the medium pressure unit 22 in the first direction and is a region that receives pressure from the medium pressure unit 22. As shown by the arrows in Fig. 3, the force Fβ acting on the energy storage module 2 from the medium pressure region 10β is smaller than the force Fα acting on the energy storage module 2 from the high pressure region 10α.

[0026] The low pressure region 10γ is a region that does not overlap with any of the pressure members 20 in the first direction. As shown by the arrows in Fig. 3, the force Fγ acting on the energy storage module 2 from the low pressure region 10γ is smaller than the force Fβ acting on the energy storage module 2 from the medium pressure region 10β.

[0027] As described above, in the restraint member 4 of this embodiment, the force Fγ acting on each energy storage cell 2a from the low pressure region 10γ is smaller than the forces Fα and Fβ acting on each energy storage cell 2a from the pressure region 10P. Therefore, as shown in Fig. 3, the gas G generated in the energy storage module 2 moves from a portion of the energy storage module 2 that overlaps with the pressure region 10P in the first direction to a portion that overlaps with the low pressure region 10γ in the first direction, and also moves along the third direction. This promotes the discharge of the gas G generated in the energy storage module 2. Note that in Fig. 3, the gas G before it moves is indicated by a two-dot chain line.

[0028] Furthermore, each pressure member 20 has a high pressure portion 21 extending along the third direction, which increases the bending rigidity of the restraint member 4. This prevents the clamping portion 10, pressure member 20, and pressing portion 30 from being bent due to tightening by the tightening member 40. This effectively ensures the restraint pressure of the energy storage module 2 at the center of the restraint member 4 in the third direction.

[0029] Furthermore, since each pressure applying portion 20 is formed hollow, the heat capacity and weight of the restraining member 4 are reduced.

[0030] In the above embodiment, as shown in Fig. 4, a general-purpose aluminum frame (an aluminum frame with grooves formed on each side) generally known as a structural material may be used as each pressure unit 20. The grooves on each side extend in the third direction. In the embodiment shown in Fig. 2 and the embodiment shown in Fig. 4, the clamping unit 10 and the multiple pressure units 20 may be integrally formed.

[0031] 5, the clamping unit 10, the pressure applying units 20, and the pressing unit 30 may be integrally formed by pultrusion, extrusion, etc. In this example, each pressure applying unit 20 is composed of only a high pressure applying unit 21, and the clamping unit 10 has only a high pressure applying region 10α and a low pressure applying region 10γ.

[0032] 6, each pressure applying unit 20 may have a honeycomb structure. The honeycomb structure has a plurality of cylindrical portions, each of which is formed into a hexagonal cylindrical shape with its central axis parallel to the first direction. An adhesive member may be provided between each pressure applying unit 20 and the pressing unit 30.

[0033] As shown in FIG. 7, the connecting portion 23 of the pressure applying portion 20 may be omitted.

[0034] It will be appreciated by those skilled in the art that the exemplary embodiments described above are examples of the following aspects.

[0035] In the above embodiment, the restraint member includes a pair of clamping portions that clamp a storage module including a plurality of storage cells stacked in a first direction from both sides in the first direction; a plurality of pressure applying portions arranged outside each of the pair of clamping portions in the first direction and spaced apart in a second direction perpendicular to the first direction; and a pair of pressing portions that are arranged outside the plurality of pressure applying portions in the first direction and press the plurality of pressure applying portions toward each of the pair of clamping portions, wherein each of the plurality of pressure applying portions has a shape whose dimension in a third direction perpendicular to both the first direction and the second direction is longer than its dimension in the first direction and its dimension in the second direction, and is in contact with the clamping portion and the pressing portion, and each of the pair of clamping portions includes a pressure applying region that overlaps with each of the pressure applying portions in the first direction and a low pressure applying region that does not overlap with the pressure applying portions in the first direction.

[0036] In this restraint member, the force acting on the energy storage module from the low-pressure region is smaller than the force acting on the energy storage module from the pressurized region, so gas generated in the energy storage module moves from the portion of the energy storage module that overlaps with the pressurized region in the first direction to the portion that overlaps with the low-pressure region in the first direction, and also moves along the third direction, thereby facilitating the discharge of gas generated in the energy storage module.

[0037] Furthermore, each of the pressure applying sections may have a pair of high pressure applying sections that face each other at a distance in the second direction and contact the clamping section and the pressing section, and a medium pressure applying section that connects the pair of high pressure applying sections and contacts the clamping section, and the pressure applying region may have a pair of high pressure applying regions that overlap with each of the pair of high pressure applying sections in the first direction and are subjected to pressure from each of the high pressure applying sections, and a medium pressure applying region that overlaps with the medium pressure applying section in the first direction and is subjected to pressure from the medium pressure applying section.

[0038] In this way, gas is effectively discharged from the portion of the power storage cell that overlaps with the low pressure region in the first direction, as well as from the portion that overlaps with the medium pressure region in the first direction.

[0039] Each of the pressure applying portions may further include a connecting portion that connects outer ends of the pair of high pressure applying portions in the first direction and that contacts the pressing portion.

[0040] Furthermore, it is preferable that the outer shape of the energy storage module in a planar view is rectangular with one side measuring 0.2 m or more, and that the outer shape of the area in which the multiple pressure applying sections are arranged in a planar view is the same as or larger than the outer shape of the energy storage module in a planar view.

[0041] In this embodiment, it is possible to restrict the entire area of ​​the electricity storage module formed in a rectangular shape with one side of 0.2 m or more in plan view.

[0042] Moreover, the power storage device in the above embodiment includes the restraining member and the power storage module, and the power storage module is restrained by the restraining member from both sides in the first direction.

[0043] It should be noted that the embodiments disclosed herein are illustrative in all respects and should not be considered limiting. The scope of the present invention is defined by the claims rather than the description of the above embodiments, and further includes all modifications within the meaning and scope of the claims. [Explanation of symbols]

[0044] 1 Energy storage device, 2 Energy storage module, 2a Energy storage cell, 4 Restraint member, 10 Clamping portion, 10P Pressure region, 10α High pressure region, 10β Medium pressure region, 10γ Low pressure region, 20 Pressure portion, 21 High pressure portion, 22 Medium pressure portion, 30 Pressing portion, 40 Fastening member, 101 Current collecting foil, 102 Positive electrode layer, 103 Negative electrode layer, 110 Separator.

Claims

1. a pair of clamping portions that clamp a storage module including a plurality of storage cells stacked in a first direction from both sides in the first direction; a plurality of pressure units arranged at intervals in a second direction perpendicular to the first direction on the outer sides of each of the pair of clamping units in the first direction; a pair of pressing units that are arranged outside the plurality of pressure units in the first direction and press the plurality of pressure units toward each of the pair of clamping units, each of the plurality of pressure applying portions has a shape in which a dimension in a third direction perpendicular to both the first direction and the second direction is longer than a dimension in the first direction and a dimension in the second direction, and is in contact with the clamping portion and the pressing portion; Each of the pair of clamping portions is a pressure region overlapping each of the pressure portions in the first direction; a low pressure region that does not overlap with the pressure portion in the first direction, Each of the pressure applying units is a pair of high pressure sections that face each other at an interval in the second direction and are in contact with the clamping section and the pressing section; a medium pressure section that connects the pair of high pressure sections and is in contact with the clamping section, The pressure region is a pair of high pressure regions overlapping the pair of high pressure portions in the first direction and receiving pressure from the pair of high pressure portions; a medium pressure region that overlaps with the medium pressure portion in the first direction and receives pressure from the medium pressure portion.

2. The restraining member according to claim 1 , wherein each of the pressure applying portions further includes a connecting portion that connects outer ends of the pair of high pressure applying portions in the first direction and that contacts the pressing portion.

3. 3. The restraint member according to claim 1, wherein the outer shape of the energy storage module in plan view is formed into a rectangular shape with sides of 0.2 m or more, and the outer shape of the area in which the plurality of pressure members are arranged in plan view is formed to be the same as or larger than the outer shape of the energy storage module in plan view.

4. A restraining member according to any one of claims 1 to 3; a power storage device including the power storage module, The energy storage device, wherein the energy storage module is restrained from both sides in the first direction by the restraining members.

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