Power storage device

Abstract

A power storage device according to the present disclosure includes: a power storage cell including an electrode body, a bottomed cylindrical housing that accommodates the electrode body, and a plate-shaped member that at least partially closes off an opening of the housing and has an edge portion fixed to a caulking portion of the housing; a holder that holds the power storage cell therein; and an annular elastic body having one surface which is in contact with at least one among the caulking portion and an inner portion of a surface, of the plate-shaped member, adjacent to the caulking portion, and the other surface which is positioned on the opposite side of the one surface and is in contact with the holder.

Description

Power storage device

[0001] The present disclosure relates to a power storage device.

[0002] In order to protect a power storage cell composed of a secondary battery or the like from an external impact or the like, a power storage device in which the power storage cell is housed in a holder is known. For example, Japanese Patent Application Laid-Open No. 2016-207569 describes a battery pack including a battery holder that holds a plurality of cylindrical batteries in an aligned state.

[0003] By the way, many power storage cells contain a liquid such as an electrolyte inside, or contain a material that corrodes due to moisture. Therefore, maintaining the airtightness of the power storage cell is important for avoiding problems with the power storage device. However, there is still room for improvement in the existing power storage device from the perspective of the airtightness of the power storage cell.

[0004] In view of the above problems, an object of the present disclosure is to provide a power storage device that suppresses a decrease in the airtightness of a power storage cell.

[0005] To achieve the above object, a power storage device according to a first aspect of the present disclosure includes an electrode body, a bottomed cylindrical housing that houses the electrode body, a plate-like member that at least partially closes an opening of the housing and has an edge fixed to a caulking portion of the housing, a power storage cell including the above, a holder that holds the power storage cell inside, the caulking portion, and an annular elastic body in which at least one of the caulking portion and an inner portion adjacent to the caulking portion on the surface of the plate-like member abuts on one surface, and the other surface located on the opposite side of the one surface abuts on the holder.

[0006] In the power storage device according to the first aspect, by pressing the caulking portion or its periphery with an annular elastic body to bring the caulking portion and the plate-like member into close contact, the airtightness of the caulking portion can be improved.

[0007] A power storage device according to a second aspect of the present disclosure is the power storage device according to the first aspect of the present disclosure, wherein the one surface of the elastic body faces the caulking portion.

[0008] In the power storage device according to the second aspect, the caulking portion can be directly pressed, and the caulking portion and the plate-like member can be brought into close contact.

[0009] A third aspect of the present disclosure relates to a power storage device according to the first aspect of the present disclosure, wherein one surface of the elastic body faces the inner portion adjacent to the crimped portion of the surface of the plate-like member.

[0010] In the third embodiment of the energy storage device, the crimped portion and the plate-shaped member can be brought into close contact by pressing the inner side adjacent to the crimped portion of the plate-shaped member. In addition, the end of the crimped portion can be closed by covering the portion adjacent to the crimped portion with an elastic material.

[0011] A fourth aspect of the present disclosure relates to a power storage device according to the first aspect of the present disclosure, wherein one surface of the elastic body faces the crimped portion and the inner portion of the surface of the plate-like member adjacent to the crimped portion.

[0012] In the fourth embodiment of the energy storage device, both the crimped portion and the inner side adjacent to the crimped portion of the plate-like member can be pressed, allowing the crimped portion and the plate-like member to be brought into close contact. In addition, the end of the crimped portion can be closed by covering the portion adjacent to the crimped portion with an elastic material.

[0013] A fifth aspect of the present disclosure relates to a fourth aspect of the present disclosure, wherein the thickness of the elastic body in the first portion facing the crimped portion is thinner than the thickness of the second portion facing the inner portion adjacent to the crimped portion on the surface of the plate-like member.

[0014] In the fifth embodiment of the energy storage device, both the crimped portion and the inner side adjacent to the crimped portion of the plate-shaped member can be pressed with a desired pressing force.

[0015] A sixth aspect of the present disclosure relates to a power storage device according to the first aspect of the present disclosure, wherein the holder includes a support surface that faces the crimped portion and the inner portion of the surface of the plate-like member adjacent to the crimped portion.

[0016] In the sixth embodiment of the energy storage device, the portion of the elastic body facing the crimped portion and the inner portion of the plate-shaped member adjacent to the crimped portion can be supported by being sandwiched between the holder and the energy storage cell, and a desired pressing force can be applied to the crimped portion and the inner portion of the plate-shaped member adjacent to the crimped portion.

[0017] A seventh aspect of the present disclosure is a power storage device according to any one of the first to sixth aspects of the present disclosure, wherein the plate-shaped member comprises a valve having a pressure-sensitive portion that operates based on pressure in the center of a plan view and a non-pressure-sensitive portion located around the pressure-sensitive portion and having its edge fixed to the crimped portion, and the one surface of the elastic body is in contact with the non-pressure-sensitive portion.

[0018] In the seventh embodiment of the energy storage device, since the elastic body does not come into contact with the pressure-sensitive part, the function of the valve is not obstructed.

[0019] An energy storage device according to the eighth aspect of the present disclosure is an energy storage device according to any one of the first to sixth aspects of the present disclosure, wherein the plate-shaped member comprises a valve having a vent hole provided adjacent to the center of the plate-shaped member in a plan view, and the one surface of the elastic body abuts outward from the vent hole of the plate-shaped member.

[0020] In the energy storage device according to the eighth embodiment, the elastic body does not block the vent hole, and therefore does not impede the function of the valve.

[0021] An energy storage device according to a ninth aspect of the present disclosure is an energy storage device according to a first aspect of the present disclosure, wherein the holder includes a fitting portion that fits with the elastic body.

[0022] In the energy storage device according to the ninth embodiment, the positioning of the elastic body relative to the holder can be reliably achieved.

[0023] A power storage device according to a tenth aspect of the present disclosure is a power storage device according to a first aspect of the present disclosure, wherein the elastic body further includes a lip portion that extends from an arbitrary position on the first portion facing the crimping portion toward the inner portion of the surface of the plate-like member adjacent to the crimping portion, and whose end portion abuts against the inner portion of the surface of the plate-like member adjacent to the crimping portion.

[0024] In the energy storage device according to the tenth embodiment, the lip portion can close the end of the crimped portion, and an improvement in the airtightness of the crimped portion can be expected.

[0025] An energy storage device according to an eleventh aspect of the present disclosure is an energy storage device according to the first aspect of the present disclosure, wherein the elastic body further includes a third portion extending from the outside of the first portion facing the crimped portion along the outer surface of the housing.

[0026] In the energy storage device according to the eleventh embodiment, positioning between the elastic body and the energy storage cell becomes easier.

[0027] The energy storage device of this disclosure can suppress the deterioration of the airtightness of the energy storage cell.

[0028] This is a schematic cross-sectional view showing an example of an energy storage device according to the first embodiment of the present disclosure. This is an enlarged cross-sectional view of part A in Figure 1. This is an enlarged cross-sectional view of a main part showing a first modified example of the elastic body. This is an enlarged cross-sectional view of a main part showing a second modified example of the elastic body. This is an enlarged cross-sectional view of a main part showing a third modified example of the elastic body. This is an enlarged cross-sectional view of a main part showing a fourth modified example of the elastic body. This is an enlarged cross-sectional view showing an example of an energy storage device according to the second embodiment of the present disclosure. This is an enlarged cross-sectional view showing a modified example of the energy storage device shown in Figure 7.

[0029] The following describes various embodiments for implementing this disclosure with reference to the drawings. In the following, only the necessary parts for explaining the objectives of this disclosure are schematically shown, and the explanation will primarily focus on the parts necessary for explaining the relevant sections of this disclosure. Any parts omitted from the explanation will be considered to be based on prior art. Furthermore, identical or equivalent components in the drawings are denoted by the same or similar reference numerals, and redundant explanations are omitted. Additionally, if multiple identical or equivalent components are included in the drawings, reference numerals may be assigned to only some of them for clarity.

[0030] <First Embodiment> Figure 1 is a schematic cross-sectional view illustrating an example of an energy storage device according to the first embodiment of the present disclosure. Figure 2 is an enlarged cross-sectional view of part A in Figure 1. The energy storage device 1 according to this embodiment includes an energy storage cell 10 and a holder 30 that houses the energy storage cell 10, as shown in Figures 1 and 2. In the following description, the direction of arrow X in Figure 1 may be referred to as the width direction or lateral direction, and the direction of arrow Y may be referred to as the up-down direction or height direction.

[0031] The energy storage cell 10 according to this embodiment can be made of a battery containing an electrolyte, such as a lithium-ion battery. This energy storage cell 10 includes at least an electrode body 11, a housing 12 that houses the electrode body 11 together with the electrolyte, and a plate-shaped member 13 that at least partially closes the opening of the housing 12. In this embodiment, an example of an energy storage cell 10 containing an electrolyte is shown, but an energy storage cell that does not contain liquid may also be used.

[0032] The electrode body 11 can be constructed, for example, as a wound electrode body. This electrode body 11 may have a structure in which a strip-shaped positive electrode 14 and a negative electrode 15 are wound together with a strip-shaped separator 16 interposed between them. For the positive electrode 14, metals such as cobalt, nickel, manganese, or iron phosphate-based materials can be used, either alone or in combination. For the negative electrode 15, carbon-based materials or other alloys can be used. Furthermore, a porous sheet having ion permeability and insulating properties can be used for the separator 16, and materials such as polyethylene, polyolefin resins including polypropylene, or cellulose can be used.

[0033] Furthermore, the electrolyte sealed inside the energy storage cell 10 can be an organic solvent such as ethylene carbonate, dimethyl carbonate, or diethyl carbonate in which lithium electrolyte salt is dissolved. The materials and shapes of each component constituting the electrode body 11, the type of electrolyte, etc., may be appropriately selected and adopted based on the intended use of the energy storage device 1.

[0034] The electrode body 11 may be provided with an upper insulating plate 17 and a lower insulating plate 18, respectively. The upper insulating plate 17 may have a through hole (not shown) into which a positive electrode lead 19, one end of which is electrically connected to the middle part of the winding direction of the positive electrode 14, is inserted. The other end of the positive electrode lead 19 may be electrically connected to a terminal plate 21, which will be described later.

[0035] The housing 12 can be constructed as an outer container made of a bottomed cylindrical metal container. An opening 12A is provided at the top of the housing 12, and this opening 12A is closed by a plate-shaped member 13 after the electrode body 11 and electrolyte are inserted. Furthermore, this housing 12 can function as a negative electrode terminal electrically connected to the negative electrode 15 by connecting a negative electrode lead (not shown) electrically connected to the end of the wound negative electrode 15 or to an appropriate location on the negative electrode 15. This housing 12 can be manufactured by forming a bottomed cylindrical shape from a metal plate by drawing or the like.

[0036] The plate-shaped member 13 can be configured as a sealing body that closes the opening 12A of the housing 12. The plate-shaped member 13 in this embodiment may include a terminal plate 21 to which the other end of the positive lead 19 is attached by welding or the like, a valve 22 positioned opposite the terminal plate 21, and an insulating plate 23 positioned between the terminal plate 21 and the valve 22.

[0037] The terminal plate 21 can be made of a roughly disc-shaped plate made of metal, such as aluminum, an aluminum alloy, or stainless steel (SUS). The central portion 21A of the terminal plate 21 may be made thinner than the other portions, and the central portion of the valve 22 may be joined to the upper surface of the central portion 21A by welding or adhesive bonding. In addition, a plurality of vents 21B may be formed at positions radially separated from the central portion 21A of the terminal plate 21 by a predetermined distance.

[0038] The valve 22 can be made of a roughly disc-shaped plate body with a larger diameter than the terminal plate 21. This valve 22 can be manufactured by press-forming a sheet of metal, such as aluminum or an aluminum alloy, or stainless steel. If aluminum or an aluminum alloy is used for the valve 22, the material can be shared with the terminal plate 21, and joining the valve 22 and the terminal plate 21 by welding or other means can be facilitated.

[0039] Furthermore, the valve 22 in this embodiment has different wall thicknesses in the radial direction. Specifically, a thin-walled portion 22C is provided so as to connect the radial central portion 22A and the outer peripheral portion 22B of the valve 22. In addition, the lower surface of the central portion 22A of the valve 22 is shaped to bulge downward in order to facilitate joining with the central portion 21A of the terminal plate 21. Furthermore, one or more support walls 22D may be formed on the lower surface of the outer peripheral portion 22B to support the outer peripheral edge of the insulating plate 23.

[0040] The insulating plate 23 can be made up of a substantially annular plate body with a through hole formed in the center. This insulating plate 23 is arranged so as to be sandwiched between the upper surface of the terminal plate 21 and the lower surface of the valve 22. One or more support walls 23A extending downward are formed on the outer peripheral edge of the insulating plate 23 to support the outer peripheral edge of the terminal plate 21. The terminal plate 21 is supported by the support walls 23A of the insulating plate 23, which makes it easy to position the terminal plate 21 and the valve 22. In addition, the insulating plate 23 may have multiple vents 23B formed so as to communicate with the vents 21B of the terminal plate 21 and the thin-walled portion 22C of the valve 22.

[0041] The valve 22 described above functions as a so-called explosion-proof valve, preventing damage to the housing 12 by having the thin-walled portion 22C pressed and inverted by the pressure when the pressure inside the housing 12 rises. More specifically, when the pressure inside the housing 12 rises above a predetermined value, a part of the terminal plate 21 breaks, and the central portion 21A of the terminal plate 21 and the central portion 22A of the valve 22 are displaced upward, thereby forcibly interrupting the current supplied from the energy storage cell 10. In relation to the above function, the central portion 22A of the valve 22 may be provided with a weak portion to facilitate the breakage of the terminal plate 21 when the pressure inside the housing 12 rises above a predetermined value. Furthermore, in the following description, the part of the valve 22 that operates in response to the rise in pressure inside the housing 12 will be called the pressure-sensitive portion 24, and the part that does not operate will be called the non-pressure-sensitive portion 25. In the valve 22 of this embodiment, the pressure-sensitive portion 24 corresponds to the central portion 22A and the thin-walled portion 22C, and the non-pressure-sensitive portion 25 corresponds to the outer circumference 22B.

[0042] The energy storage cell 10 is sealed by crimping and fixing the edge of the plate-shaped member 13, which includes the above-described configuration, to the crimping portion F1. Therefore, an example of the structure of the crimping portion F1 will be described below.

[0043] The caulking portion F1 is formed at the opening 12A portion of the housing 12, and caulks and fixes the outer peripheral portion 22B of the valve 22 as an example of the edge portion of the plate-like member 13 with a gasket 26 interposed therebetween. The caulking portion F1 can be clamped and caulked by a pressing device (not shown) from the vertical direction after being bent into a shape surrounding, for example, the periphery of the outer peripheral portion 22B of the valve 22. The gasket 26 functions as a sealing material for maintaining the airtightness of the power storage cell 10. In addition, the gasket 26 also has a function of electrically insulating the housing 12 and the terminal plate 21. In this regard, the gasket 26 can be made of a relatively flexible insulating material such as synthetic resin.

[0044] An annular recess 12B recessed inwardly over the entire circumference of the housing 12 may be formed between the opening 12A in the height direction of the housing 12 and the accommodation position of the upper insulating plate 17. This annular recess 12B supports the electrode body 11 and the like housed in the housing 12 within the housing 12. In addition, the upper surface of this annular recess 12B functions as a mounting surface on which the outer peripheral portion 22B of the valve 22 is placed via the gasket 26.

[0045] The opening 12A is bent with the gasket 26 interposed therebetween so as to surround the lower surface, side surface, and upper surface of the outer peripheral portion 22B of the valve 22 placed on the upper surface of the annular recess 12B. Then, by pressing from the vertical direction using a pressing device (not shown), as shown in FIGS. 1 and 2, the gasket 26 and the outer peripheral portion 22B of the valve 22 are caulked and fixed inside the opening 12A. By interposing the gasket 26 between the housing 12 and the valve 22, the caulking portion F1 ensures the airtightness of the portion and also realizes insulation between the housing 12 and the valve 22.

[0046] The holder 30 houses the power storage cell 10 with the above-described configuration and can be made of an insulating material such as a resin material. As shown in FIGS. 1 and 2, the holder 30 of the present embodiment is composed of an upper holder 31 that houses the positive electrode side of the power storage cell 10 and a lower holder 32 that houses the negative electrode side of the power storage cell 10. Note that the configurations of the upper holder 31 and the lower holder 32 may be substantially the same. In FIG. 1, one upper holder 31 and one lower holder 32 are each illustrated, but a plurality of upper holders 31 or lower holders 32 may be connected in the lateral direction.

[0047] The upper holder 31 and the lower holder 32 may include lid portions 33 and 34 that protect the power storage cell 10 by contacting the upper surface or the lower surface of the power storage cell 10, and peripheral wall portions 35 and 36 that extend along the height direction from the outer periphery of the lid portions 33 and 34 and surround the outer periphery of the power storage cell 10. Among these, the lid portions 33 and 34 can be composed of substantially disk-shaped members in which through holes for inserting a positive electrode bus bar lead 53 or a negative electrode bus bar lead 54, which will be described later, are formed at the central portions. Further, the lower surface of the lid portion 33 constitutes a support surface 37 for supporting an elastic body 40, which will be described later. Furthermore, the upper surface of the lid portion 34 constitutes a support surface 38 for supporting the bottom portion of the housing 12.

[0048] The peripheral wall portions 35 and 36 are substantially cylindrical members, and the diameter of the inner peripheral surface thereof may be adjusted to be slightly larger than the outer diameter of the power storage cell 10 housed in the holder 30. The length along the height direction of the peripheral wall portions 35 and 36 is preferably adjusted such that when the power storage cell 10 is housed in the holder 30, the tip portions of both face each other with a slight gap.

[0049] A positive electrode bus bar 51 is attached to the upper surface of the lid portion 33 of the upper holder 31. The positive electrode bus bar 51 is electrically connected to the positive electrode of the power storage cell 10, specifically, the valve 22 joined to the terminal plate 21 via the positive electrode bus bar lead 53. Similarly, a negative electrode bus bar 52 is attached to the lower surface of the lid portion 34 of the lower holder 32. The negative electrode bus bar 52 is electrically connected to the negative electrode of the power storage cell 10, specifically, the housing 12 via the negative electrode bus bar lead 54.

[0050] In the energy storage cell 10 with the configuration described above, leakage may occur due to, for example, an increase in pressure inside the housing 12 or an external impact. In addition, most of the aforementioned leakage occurs around the crimped portion F1. Therefore, ensuring the airtightness of the crimped portion F1 is important for preventing leakage. Taking the above points into consideration, the energy storage device 1 of this embodiment employs a leakage prevention structure using an elastic body 40. The leakage prevention structure will be described below.

[0051] As shown in Figures 1 and 2, the elastic body 40 may be installed between the upper outer circumference where the crimped portion F1 of the energy storage cell 10 is located and the holder 30, more specifically the upper holder 31. The elastic body 40 can be an annular member having a predetermined thickness, and a flexible material with sealing properties such as synthetic resin may be used. One surface of the elastic body 40, for example the lower surface, abuts against at least one of the crimped portion F1 and the inner portion of the surface of the plate-shaped member 13 adjacent to the crimped portion F1, while the other surface opposite to the first surface, for example the upper surface, abuts against the holder 30.

[0052] The lower surface of the elastic body 40 in this embodiment faces both the crimped portion F1 and the inner portion of the plate-shaped member 13 adjacent to the crimped portion F1, more specifically the surface of the outer peripheral portion 22B of the valve 22. In this regard, below, the outer peripheral portion of the elastic body 40 in this embodiment that faces the crimped portion F1 will be referred to as the first portion 41, and the inner peripheral portion that faces the outer peripheral portion 22B of the valve 22 adjacent to the crimped portion F1 will be referred to as the second portion 42.

[0053] It is preferable to adjust the outer diameter of the elastic body 40 so that it is substantially the same as the inner diameter of the peripheral wall portion 35 of the upper holder 31, as this makes it easy to position the elastic body 40 relative to the upper holder 31. Furthermore, the inner diameter of the elastic body 40 is adjusted so that the inner surface of the elastic body 40 is located outside the boundary between the pressure-sensitive portion 24 and the non-pressure-sensitive portion 25 of the valve 22. By adjusting the inner diameter of the elastic body 40 as described above, the second portion 42 does not come into contact with the pressure-sensitive portion 24, so that the valve 22 and the elastic body 40 do not come into contact when the valve 22 operates, and the function of the valve 22 can be maintained.

[0054] The energy storage device 1, including the elastic body 40 described above, can be assembled by, for example, performing the following process. Specifically, first, the elastic body 40 is inserted into the upper holder 31 so that one surface of the elastic body 40 is in contact with the support surface 37. Next, the positive electrode side of the energy storage cell 10 is inserted into the peripheral wall portion 35 of the upper holder 31 into which the elastic body 40 is inserted, and the crimped portion F1 of the energy storage cell 10 and the outer circumference 22B of the valve 22 adjacent to the crimped portion F1 are brought into contact with the elastic body 40. Next, the housing portion 12 of the energy storage cell 10 that is exposed outside the upper holder 31 is inserted into the lower holder 32 and housed there, and the upper holder 31 and the lower holder 32 are fixed to each other with fixing means such as bolts (not shown). At this time, it is preferable to fix the upper holder 31 and the lower holder 32 with a predetermined pressure applied so as to press the positive electrode end of the energy storage cell 10 against the elastic body 40. Finally, the assembly of the energy storage device 1 is completed by fixing the positive electrode busbar 51 and the negative electrode busbar 52 to the upper holder 31 and the lower holder 32 by welding or other means.

[0055] The upper surfaces of the first portion 41 and the second portion 42 of the elastic body 40 in this embodiment both abut against the support surface 37 of the upper holder 31. In other words, the support surface 37 of the upper holder 31 faces the crimped portion F1 and the inner portion of the surface of the plate-shaped member 13 adjacent to the crimped portion F1, i.e., the outer circumference 22B of the valve 22. More preferably, the dimensions of the upper holder 31 are adjusted so that the position of the inner circumference surface of the lid portion 33 is located inward from the position of the inner circumference surface of the elastic body 40. In addition, the thickness H1 of the first portion 41 of the elastic body 40 is adjusted to be thinner than the thickness H2 of the second portion 42. With the above configuration, when the energy storage device 1 is assembled, for example, by the process described above, the elastic body 40 of this embodiment presses the crimped portion F1 and the outer circumference 22B of the valve 22 downward with a generally equal force.

[0056] The first portion 41 of the elastic body 40 described above is pressed against the support surface 37 of the upper holder 31, thereby pressing the crimped portion F1 of the energy storage cell 10 downward. This allows the crimped portion F1 to adhere more firmly to the plate-shaped member 13 and the gasket 26, thereby improving the airtightness of the energy storage cell 10. The second portion 42 of the elastic body 40 abuts against the outer circumference 22B so as to cover the end of the crimped portion F1, more specifically the tip of the opening 12A. Therefore, even if electrolyte leaks from the tip of the opening 12A, for example, the gap between the elastic body 40 and the plate-shaped member 13 can hold the leaked electrolyte, preventing it from leaking outside the energy storage device 1. In this regard, by adjusting the position and length of the second portion 42 so as to seal the tip of the opening 12A, the elastic body 40 can also close the tip of the opening 12A.

[0057] In addition, since the energy storage cell 10 is housed in the holder 30 via the elastic body 40, it is also possible to attenuate external inputs to the holder 30, for example. Therefore, it can be said that the energy storage device 1 of this embodiment suppresses the occurrence of leakage caused by external forces by employing the elastic body 40.

[0058] As described above, according to the energy storage device 1 of this embodiment, the crimped portion F1 and the plate-shaped member 13 can be firmly bonded together by pressing the crimped portion F1 and the inner portion of the plate-shaped member 13 adjacent to the crimped portion F1 with the elastic body 40. Therefore, the airtightness of the energy storage cell 10 can be improved. In addition, even if electrolyte leaks out from the tip of the opening 12A, the second portion 41 of the elastic body 40 can prevent leakage to the outside, thus ensuring reliable prevention of leakage. In this embodiment, the case in which the energy storage cell contains liquid has been described as an example, but even if the energy storage cell does not contain liquid, the improved airtightness described above can prevent the intrusion of liquid or outside air into the energy storage cell, thereby preventing corrosion of the electrode body, etc.

[0059] In the first embodiment described above, the elastic body 40 was exemplified as including a first portion 41 that abuts against the crimped portion F1 and a second portion 42 that abuts against the outer circumference 22B of the valve 22 adjacent to the crimped portion F1. However, this disclosure is not limited thereto. Hereinafter, several modifications of the elastic body will be described with reference to Figures 3 to 6. In each of the modifications described below, the explanation will focus on parts that are different from the components of the energy storage device 1 according to the first embodiment described above. Parts that are the same as the components of the energy storage device 1 are given the same reference numerals as those used in the first embodiment and their explanations are omitted. Furthermore, the figures shown in Figures 3 to 6 are enlarged views of only the left portion of the cross-sectional view shown in Figure 2.

[0060] Figure 3 is an enlarged cross-sectional view of the main part showing the first modified example of the elastic body. As shown in Figure 3, the lower surface of the elastic body 40A according to the first modified example faces the crimped portion F1. In other words, the elastic body 40A of this modified example includes a first portion that faces the crimped portion F1, but does not include a second portion that faces the outer circumference 22B of the valve 22, which is located inside the aforementioned crimped portion F1. In relation to the structure of the elastic body 40A described above, the lid portion 33A of the upper holder in this modified example can also be shaped to face only the crimped portion F1.

[0061] Even when an elastic body 40A is used as shown in this modified example, the crimped portion F1 and the plate-shaped member 13 can be firmly pressed together by directly pressing the crimped portion F1 with the elastic body 40A, thereby improving the airtightness of the energy storage cell 10.

[0062] Figure 4 is an enlarged cross-sectional view of the main part showing a second modified example of the elastic body. As shown in Figure 4, the lower surface of the elastic body 40B according to the second modified example faces the outer circumference 22B of the valve 22. In other words, the elastic body 40B of this modified example faces only the outer circumference 22B of the valve 22, whose surface is exposed inside the crimped portion F1, and does not face the crimped portion F1.

[0063] In this modified example, the elastic body 40B is preferably positioned so as to overlap the bottom of the annular recess 12B (specifically, the part indicated by the straight line L in Figure 4) in a plan view, as this makes it less likely for the housing 12 to deform due to the downward pressure applied by the elastic body 40B. In addition, it is even more preferable to position the outer peripheral end of the elastic body 40B adjacent to or partially overlapping the gasket 26, as shown in Figure 4, as this suppresses leakage from the gasket 26.

[0064] Even when an elastic body is used as shown in this modified example, the elastic body 40B can press against the outer circumference 22B of the valve 22 adjacent to the crimped portion F1, thereby firmly bonding the crimped portion F1 and the plate-shaped member 13, and improving the airtightness of the energy storage cell 10.

[0065] Figure 5 is an enlarged cross-sectional view of a key part showing a third modified example of the elastic body. As shown in Figure 5, the elastic body 40C according to the third modified example further includes a first portion 41 facing the crimped portion F1 and a second portion 42 facing the outer circumference 22B of the valve 22 adjacent to the crimped portion F1, as well as a third portion 43 extending from the outside of the first portion 41 along the outer surface of the housing 12.

[0066] As shown in Figure 5, the third portion 43 of this modified example has its outer circumferential surface in contact with the peripheral wall portion 35 of the upper holder 31, and its inner circumferential surface is formed as a tapered surface. By configuring the third portion 43 as described above, the third portion 43 can function as a guide when inserting the energy storage cell 10 into the upper holder 31. Furthermore, by adopting the third portion 43, the contact area between the elastic body 40C and the peripheral wall portion 35 of the upper holder 31 is increased, and the position of the elastic body 40C relative to the upper holder 31 can be made more stable. In addition, since the elastic body 40C of this modified example includes the first portion 41 and the second portion 42, the same effects as the first embodiment described above can be obtained.

[0067] Furthermore, in order to more reliably position the elastic body 40C relative to the upper holder 31, as shown in Figure 5, one or more protrusions 39 can be used on the inner surface of the upper holder 31 as an example of a fitting portion that engages with the elastic body 40C. These protrusions 39 can be formed, for example, to stand upright on the support surface 37 of the upper holder 31. It is also preferable to provide fitting holes (not shown) at corresponding positions on the elastic body 40C into which the protrusions 39 are inserted or press-fitted. By using the above-described protrusions 39 on the upper holder 31, the elastic body 40C can be supported at a desired position regardless of its outer diameter, etc. In this modified example, a case in which multiple protrusions 39 are used as fitting portions is illustrated, but the shape, number, and arrangement of the fitting portions can be appropriately changed within a range that maintains the function of supporting the elastic body. In addition, the configuration of the third portion 43 and the protrusions 39 described above can be additionally applied to each embodiment and each modified example illustrated in this specification.

[0068] Figure 6 is an enlarged cross-sectional view of the main part showing a fourth modified example of the elastic body. The elastic body 40D according to the fourth modified example is common with the elastic body 40A according to the first modified example described above, in that it has a first portion facing the crimped portion F1, as shown in Figure 6. On the other hand, the elastic body 40D of this modified example further includes a lip portion 44 that extends from an arbitrary position on the first portion facing the crimped portion F1 toward the inner portion adjacent to the crimped portion F1 on the surface of the plate-shaped member 13. The lip portion 44 of this modified example extends diagonally from the inner circumferential surface of the first portion of the elastic body 40D toward the non-pressure-sensitive portion 25 of the plate-shaped member 13, more specifically toward the outer circumferential portion 22B of the valve 22, and its tip abuts against the outer circumferential portion 22B of the valve 22. Because the elastic body 40D has the above-described configuration, the tip of the opening 12A of this modified example is covered by the lip portion 44.

[0069] When an elastic body 40D as shown in this modified example is used, in addition to the effects described in the first modified example, the tip of the opening 12A is sealed by the lip portion 44, thus reliably preventing leakage.

[0070] <Second Embodiment> In the first embodiment described above, the energy storage cell 10 was exemplified as having a valve 22 including a pressure-sensitive part 24 and a non-pressure-sensitive part 25. However, the energy storage cells that can be used in this disclosure are not limited to this. Therefore, below, as a second embodiment of this disclosure, an energy storage device 100 including an energy storage cell 110 with a different configuration from the energy storage cell 10 described above will be described exemplarily. Note that some of the components of the energy storage device 100 according to this embodiment are common to the energy storage device 1 according to the first embodiment described above. Therefore, in the following description, components that are the same as those in the first embodiment will be denoted by the same reference numerals and their descriptions will be omitted. Also, for components with the same names as components in the first embodiment, the detailed configuration etc. can be reused from the description in the first embodiment, so detailed descriptions will be omitted below.

[0071] Figure 7 is a schematic enlarged cross-sectional view showing an example of a power storage device according to a second embodiment of the present disclosure. Figure 7 is an enlarged view of a portion of the power storage device 100 according to this embodiment that is the same as portion A shown in Figure 1. As shown in Figure 7, the power storage device 100 according to this embodiment includes a power storage cell 110, a holder 30 that houses the power storage cell 110, and an elastic body 140. Of these, the holder 30 may be the same as that of the first embodiment.

[0072] The energy storage cell 110, like the energy storage cell 10 described above, includes an electrode body 111 formed by winding a positive electrode 114, a negative electrode 115, and a separator 116, a bottomed cylindrical housing 112 that houses the electrode body 111, and a plate-shaped member 113 that closes the opening 112A of the housing 112. In Figure 7, reference numeral 117 indicates the upper insulating plate.

[0073] The plate-shaped member 113 in this embodiment is composed of a valve 120. The valve 120 may include a terminal plate 121, an electrode cover 122, and a valve body 123.

[0074] The terminal plate 121 can be made of a roughly disc-shaped plate made of metal, such as aluminum, an aluminum alloy, or stainless steel. The terminal plate 121 may be electrically connected to the positive electrode 114 by connecting the positive electrode lead 119 to an appropriate location on its lower surface. In addition, a vent 124 is formed in the center of the terminal plate 121, and the area around the vent 124 functions as a valve seat that supports the valve body 123.

[0075] The electrode cover 122 is positioned above the terminal plate 121 and can be made of a plate-shaped member including a raised portion 122A that rises upward in its center. This electrode cover 122 can be made of metal, such as aluminum or an aluminum alloy similar to the terminal plate 121, or stainless steel. The electrode cover 122 is connected to the positive electrode busbar 51 by connecting the positive electrode busbar lead 53 to the upper surface of the raised portion 122A. The outer periphery of the electrode cover 122, which is provided around the raised portion 122A, may be attached to the upper surface of the terminal plate 121 by welding or the like. The outer periphery of the electrode cover 122 and the outer periphery of the terminal plate 121 are placed on the annular recess 112B via a gasket 126 and crimped and fixed to the crimped portion F2 of the housing 112. Furthermore, one or more ventilation holes 125 may be provided at a position adjacent to the center of the electrode cover 122, specifically on the side surface of the raised portion 122A.

[0076] The valve body 123 can be a roughly tablet-shaped (roughly cylindrical) member housed within the area enclosed by the central part 122A of the electrode cover 122 and the terminal plate 121, so as to block the vent 124. The valve body 123 is lifted upward when the pressure inside the energy storage cell 110 rises, thereby releasing the pressure inside the energy storage cell 110 to the outside through the vent hole 125.

[0077] The elastic body 140, like the elastic body 40 in the first embodiment described above, can be an annular member having a predetermined thickness, and is installed between the upper outer circumference of the energy storage cell 110 and the upper holder 31. The lower surface of the elastic body 140 abuts against the crimped portion F2 and the inner portion adjacent to the crimped portion F2 on the surface of the plate-shaped member 113, more specifically the surface of the electrode cover 122 of the valve 120, and the upper surface abuts against the holder 30.

[0078] The elastic body 140 of this embodiment includes a first portion 141 facing the crimped portion F2 and a second portion 142 facing the outer peripheral portion located outside the raised portion 122A of the electrode cover 122. Here, the inner diameter of the elastic body 140 is adjusted so that the inner surface of the elastic body 140 is located outside the ventilation hole 125. By adjusting the inner diameter of the elastic body 140 as described above, the second portion 142 does not block the ventilation hole 125, and thus the function of the valve 120 can be maintained.

[0079] The energy storage device 100 having the above-described configuration can also obtain the same effects as those described for the energy storage device 1 of the first embodiment. Furthermore, the energy storage device 100 according to the second embodiment can also adopt the configuration exemplified as a modification in the first embodiment.

[0080] Figure 8 is an enlarged cross-sectional view showing a modified example of the energy storage device shown in Figure 7. In the second embodiment, the energy storage device 100 is exemplified by using a substantially tablet-shaped valve body 123 as the valve 120 of the energy storage cell, but the present disclosure is not limited thereto. Hereafter, as a modified example of the second embodiment, an energy storage device 100A in which the plate-shaped member included in the energy storage cell is changed will be described below with reference to Figure 8. Note that the energy storage device 100A according to this modified example may have the same configuration as the energy storage device 100 according to the second embodiment, except that the configuration of the energy storage cell 110A, or more specifically the configuration of the plate-shaped member 213 included in the energy storage cell 110A, is different. Therefore, in the following description of the energy storage device 100A according to this modified example, components of the energy storage device 100A according to this modified example that are the same as those in the second embodiment will be denoted by the same reference numerals and their descriptions will be omitted.

[0081] As shown in Figure 8, the energy storage cell 110A of the energy storage device 100A according to this modified example includes an electrode body 111, a housing 112, and a plate-shaped member 213. Of these, the plate-shaped member 213 includes a valve 220 and a terminal plate 221.

[0082] The terminal plate 221 can be made of a roughly disc-shaped plate made of metal, such as aluminum, an aluminum alloy, or stainless steel. The terminal plate 221 may be electrically connected to the positive electrode 114 by connecting the positive electrode lead 119 to an appropriate location on its lower surface. In addition, multiple ventilation holes 221A may be formed in appropriate locations on the terminal plate 221, for example, around the central part.

[0083] The valve 220 may include an electrode cover 222, an upper valve body 223, a lower valve body 224, and an insulating plate 227. Of these, the electrode cover 222 is disposed above the terminal plate 221 and can be made of a plate-shaped member including a raised portion 222A that rises upward in its central part. This electrode cover 222 can be made of metal, such as aluminum, an aluminum alloy, or stainless steel, similar to the terminal plate 221. The electrode cover 222 is connected to the positive electrode busbar 51 by a positive electrode busbar lead 53 being connected to its upper surface. Furthermore, one or more ventilation holes 225 may be provided at a position adjacent to the central part of the electrode cover 222, specifically at the corner above the raised portion 122A.

[0084] The upper valve body 223 can be made of a relatively thin, roughly disc-shaped member that is installed below the electrode cover 222 and electrically connected to the electrode cover 222. The lower valve body 224 can also be made of a relatively thin, roughly disc-shaped member that is laminated on the upper surface of the terminal plate 221 and electrically connected to the terminal plate 221. The central portion 224A of the lower valve body 224 is raised upward, and this central portion 224A may be joined to the lower surface of the upper valve body 223 by welding or using a conductive adhesive or the like.

[0085] The insulating plate 227 can be made up of a substantially annular plate body with a through hole formed in the center. This insulating plate 223 is arranged so as to be sandwiched between the upper valve body 223 and the lower valve body 224.

[0086] In the energy storage cell 110A, which includes the plate-shaped member 213 with the above configuration, if the internal pressure inside the energy storage cell 110A rises due to, for example, heat generation from the electrode body 111, the lower valve body 224 deforms and breaks, pushing up the upper valve body 223. The breakage of the lower valve body 224 interrupts the electrical connection between the terminal plate 221 and the electrode cover 222. In addition, the gas inside the energy storage cell 110A is discharged to the outside through the vent hole 225 via the broken lower valve body 224.

[0087] In this modified example, the energy storage cell 110A has the outer periphery of the plate-shaped member 213 with the above-described configuration crimped and fixed to the crimped portion F3 of the housing 112 via a gasket 126. Then, at least one of the crimped portion F3 and the inner portion of the plate-shaped member 213 adjacent to the crimped portion F3 comes into contact with the elastic body 140, thereby improving the airtightness of the crimped portion F3, similar to the second embodiment.

[0088] This disclosure is not limited to the embodiments described above, and can be implemented with various modifications without departing from the spirit of this disclosure. All such modifications are included in the technical concept of this disclosure. Furthermore, unless otherwise specified in the specification, each component of this disclosure is not limited to one, but may exist in multiple forms.

[0089] The disclosure of Japanese Patent Application No. 2024-166567, filed on 25 September 2024, is incorporated herein by reference in its entirety. All documents, patent applications, and technical standards described herein are incorporated herein by reference in the same way as if the incorporation of each individual document, patent application, and technical standard were specifically and individually described.

Claims

1. An energy storage device comprising: an electrode body; a bottomed cylindrical housing housing the electrode body; a plate-shaped member that at least partially closes the opening of the housing and whose edge is fixed to a crimped portion of the housing; a holder that holds the energy storage cell internally; and an annular elastic body whose one surface abuts against the crimped portion and at least one inner portion of the surface of the plate-shaped member adjacent to the crimped portion, and whose other surface located opposite the one surface abuts against the holder.

2. The energy storage device according to claim 1, wherein one surface of the elastic body faces the crimped portion.

3. The energy storage device according to claim 1, wherein the one surface of the elastic body faces the inner portion adjacent to the crimped portion of the surface of the plate-shaped member.

4. The energy storage device according to claim 1, wherein one surface of the elastic body faces the crimped portion and the inner portion of the surface of the plate-like member adjacent to the crimped portion.

5. The energy storage device according to claim 4, wherein the thickness of the first portion of the elastic body facing the crimped portion is thinner than the thickness of the second portion facing the inner portion of the surface of the plate-like member adjacent to the crimped portion.

6. The energy storage device according to claim 1, wherein the holder includes a support surface that faces the crimped portion and the inner portion of the surface of the plate-like member adjacent to the crimped portion.

7. The energy storage device according to any one of claims 1 to 6, wherein the plate-shaped member comprises a valve having a pressure-sensitive portion that operates based on pressure in the center of a plan view and a non-pressure-sensitive portion located around the pressure-sensitive portion and whose edge is fixed to the crimping portion, and one surface of the elastic body is in contact with the non-pressure-sensitive portion.

8. The energy storage device according to any one of claims 1 to 6, wherein the plate-shaped member comprises a valve having a ventilation hole provided adjacent to the center of the plate-shaped member in a plan view, and the one surface of the elastic body abuts outward from the ventilation hole of the plate-shaped member.

9. The energy storage device according to claim 1, wherein the holder comprises a fitting portion that engages with the elastic body.

10. The energy storage device according to claim 1, wherein the elastic body further comprises a lip portion that extends from an arbitrary position on the first portion facing the crimping portion toward the inner portion of the surface of the plate-like member adjacent to the crimping portion, and whose end contacts the inner portion of the surface of the plate-like member adjacent to the crimping portion.

11. The energy storage device according to claim 1, wherein the elastic body further comprises a third portion extending from the outside of the first portion facing the crimping portion along the outer surface of the housing.

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