WO2019131356A1

WO2019131356A1 - Electricity storage device

Info

Publication number: WO2019131356A1
Application number: PCT/JP2018/046674
Authority: WO
Inventors: 美恵子山崎; 憲利前田
Original assignee: 株式会社Ｇｓユアサ
Priority date: 2017-12-28
Filing date: 2018-12-19
Publication date: 2019-07-04
Also published as: JPWO2019131356A1

Abstract

An electricity storage device (electricity storage element (10)) comprises a first member (positive electrode current collector (500) (electrode connection unit (520))), and a second member (electrode body (400) (positive electrode convergence section (410))) disposed on a first direction side of the first member. The first member and the second member have a crimp junction section (20) having an uneven structure that protrudes towards the first direction. The crimp junction section (20) has a first protrusion (electrode body first protrusion (411)) where the second member protrudes in the first direction, a first recess (current collector first recess (523)) where the first member is recessed in the first direction, and a second recess (current collector second recess (524)) that is recessed in the first direction from the first recess.

Description

Power storage device

The present invention relates to a power storage device comprising two members joined by caulking.

2. Description of the Related Art Conventionally, a power storage device comprising two members joined by caulking is known. In Patent Document 1, in a tab lead formed by joining a metal plate for solder connection to a lead body connected to an electrode in a non-aqueous electrolyte device, the lead body has a hook portion, and the metal plate A non-aqueous electrolyte battery (power storage device) is disclosed that is configured to wrap around a portion and be fitted into the bowl.

Unexamined-Japanese-Patent No. 2015-32441

However, in a configuration in which two members are crimped and joined as in the above-mentioned conventional power storage device, there is a risk that the joining of the two members may be loosened or separated due to external vibration or impact. . Therefore, further improvement of the bonding strength of the two members is desired.

An object of the present invention is to provide a power storage device capable of improving the bonding strength of two members joined by caulking.

A power storage device according to one aspect of the present invention is a power storage device including a power storage element, comprising: a first member; and a second member disposed on a first direction side of the first member, The member and the second member have a caulking joint portion formed of a concavo-convex structure projecting in the first direction, and the caulking joint portion is a first member in which the second member protrudes in the first direction. It has a convex part, the 1st crevice in which the said 1st member was dented in the said 1st direction, and the 2nd crevice dented in the said 1st direction from the 1st crevice.

According to the power storage device of the present invention, the bonding strength of the two members joined by caulking can be improved.

FIG. 1 is a perspective view showing the appearance of a storage element according to the embodiment. FIG. 2 is a perspective view showing components arranged inside the container of the storage element according to the embodiment. FIG. 3 is an exploded perspective view showing each component by decomposing the storage element according to the embodiment. FIG. 4 is a cross-sectional view showing a configuration in which the positive electrode current collector according to the embodiment is joined to the positive electrode focusing portion of the electrode assembly. FIG. 5 is a perspective view and a cross-sectional view showing the configuration of a crimp joint according to the embodiment. FIG. 6 is a cross-sectional view showing the configuration of a crimp joint according to Modification 1 of the embodiment. FIG. 7 is a cross-sectional view showing the configuration of a crimp joint according to Modification 2 of the embodiment.

According to this, in the power storage device, the crimped joint portion formed on the first member and the second member includes the first convex portion in which the second member protrudes in the first direction, and the first member is recessed in the first direction. And a second recess recessed from the first recess in the first direction. That is, at the caulking joint portion, the first convex portion is formed in the second member, and the first concave portion is formed in the first member to form the second concave portion in the first concave portion. As described above, by forming the second recess in the first recess at the time of caulking bonding, the portion located at the position of the second recess spreads to the outside of the second recess, and the bonding portion is compressed. Thereby, the joint strength of the crimped joint can be improved, and the joint strength of the two members (first member and second member) joined by caulking can be improved.

The first concave portion may have an end on the first direction side inward of an outer edge of the first convex portion on the first direction side when viewed from the first direction.

According to this, in the caulking joint, the first concave portion is arranged such that the end on the first direction side is inward of the outer edge of the first convex portion on the first direction side when viewed from the first direction. It is done. That is, at the time of caulking and bonding, the first concave portion is formed inward of the first convex portion. As a result, the portion at the position of the first recess can be spread outside the first recess with a relatively small force, and the bonding portion can be pressed, so that the bonding strength of the caulked bonding portion can be relatively easily improved.

The first member has a first portion disposed on the first direction side of the second recess, and a thickness of the first portion in the first direction is the first direction of the second recess. It may be smaller than the depth.

According to this, in the caulking joint, the first member has the first portion disposed on the first direction side of the second recess, and the thickness of the first portion is smaller than the depth of the second recess. That is, the first part is pressed until the thickness of the first part on the first direction side of the second recess in the first member becomes smaller than the depth of the second recess. Thereby, since the 1st part which existed in the position of the 2nd recessed part spreads on the outer side of the 2nd recessed part, and a junction part is pressed, the junction intensity of a crimp junction part can be improved.

The first member includes a first portion disposed on the first direction side of the second recess, and a second portion disposed on the second direction side intersecting the first direction of the first recess. The thickness in the first direction of the first part may be smaller than the thickness in the second direction of the second part.

According to this, in the caulking joint portion, the first member is disposed in the second direction side intersecting the first direction of the first recess portion and the first portion disposed in the first direction side of the second recess portion And a thickness of the first part is smaller than a thickness of the second part. That is, the first part is pressed until the thickness of the first part on the first direction side of the second recess in the first member is smaller than the thickness of the second part on the second direction side of the first recess. Thereby, since the 1st part which existed in the position of the 2nd recessed part spreads on the outer side of the 2nd recessed part, and a junction part is pressed, the junction intensity of a crimp junction part can be improved.

The caulking joint further includes a second convex portion in which the first member protrudes in the first direction, and a third convex portion which protrudes in the first direction from the second convex portion. It is also good.

According to this, the caulking joint portion has the second convex portion in which the first member protrudes in the first direction, and the third convex portion which protrudes in the first direction from the second convex portion. That is, at the crimped joint, the first member has the two-step convex portion. Thereby, a two-step interlock is applied between the first member and the second member, and the bonding strength of the crimped joint can be further improved.

The storage element may have an electrode body, and the first member and the second member may be conductive members disposed in a path of current flowing through the electrode body.

According to this, since the first member and the second member are conductive members disposed in the path of the main current, there is a possibility that the performance of the power storage device may be reduced due to the decrease in the bonding strength. For this reason, the effect by the improvement of the joint strength of the first member and the second member is large.

The present invention can be realized not only as such a power storage device, but also as two members (a first member and a second member) included in the power storage device.

Hereinafter, an electric storage device as an electric storage device according to the embodiment of the present invention (and its modification) will be described with reference to the drawings. The embodiments described below are all inclusive or specific examples. The numerical values, shapes, materials, components, arrangement positions and connection forms of the components, and the like described in the following embodiments are merely examples, and are not intended to limit the present invention. Among the components in the following embodiments, components that are not described in the independent claim indicating the highest concept are described as optional components. In each of the drawings, the dimensions and the like are not strictly illustrated.

In the following description and drawings, the arrangement direction of a pair of electrode terminals of a storage element, the arrangement direction of a pair of current collectors, the arrangement direction of both end portions of an electrode body (a pair of active material layer non-formed parts), an electrode body The winding axial direction, the width direction of the legs of the current collector, or the opposing direction of the short side of the container is defined as the X-axis direction. The opposing direction of the long side of the container, the lateral direction of the short side of the container, the thickness direction of the container, the stacking direction of the electrode plates of the electrode assembly at the caulking joint, or the collector and the electrode body at the caulking joint The alignment direction with the plate is defined as the Y-axis direction. The direction in which the container body and the lid of the storage element are aligned, the longitudinal direction of the short side of the container, or the extending direction of the leg portion of the current collector is defined as the Z-axis direction. The X-axis direction, the Y-axis direction, and the Z-axis direction are directions intersecting with each other (orthogonal in the present embodiment). In the following description, the X axis plus direction indicates the arrow direction of the X axis, and the X axis minus direction indicates the direction opposite to the X axis plus direction. The same applies to the Y-axis direction and the Z-axis direction.

Embodiment
[1. General Description of Storage Element 10]
First, general description of the storage element 10 according to the present embodiment will be given using FIGS. 1 to 3. The storage element 10 is an example of a storage device including a storage element. That is, when the storage device includes only one storage element 10, the storage device is the storage element 10. Therefore, hereinafter, the storage element 10 will be described as an example of the storage device.

FIG. 1 is a perspective view showing the appearance of a storage element 10 according to the present embodiment. FIG. 2: is a perspective view which shows the component arrange | positioned inside the container 100 of the electrical storage element 10 which concerns on this Embodiment. Specifically, FIG. 2 is a perspective view showing a configuration in which the container body 111 is separated from the storage element 10. That is, the figure shows a state after the positive electrode current collector 500 and the negative electrode current collector 600 are joined to the electrode body 400. FIG. 3 is an exploded perspective view showing each component by decomposing the storage element 10 according to the present embodiment. That is, the figure shows a state before the positive electrode current collector 500 and the negative electrode current collector 600 are bonded to the electrode body 400. The container main body 111 is omitted in FIG.

The storage element 10 is a secondary battery capable of charging and discharging electricity, and specifically, a non-aqueous electrolyte secondary battery such as a lithium ion secondary battery. The storage element 10 is used as an automotive power supply such as an electric vehicle (EV), a hybrid electric vehicle (HEV), or a plug-in hybrid electric vehicle (PHEV), a power supply for electronic devices, or a power storage power supply.

The storage element 10 is not limited to the non-aqueous electrolyte secondary battery, and may be a secondary battery other than the non-aqueous electrolyte secondary battery, or may be a capacitor. The storage element 10 may not be a secondary battery, but may be a primary battery that can use the stored electricity without charging by the user. The storage element 10 may be a battery using a solid electrolyte. In the present embodiment, a rectangular parallelepiped (square) storage element 10 is illustrated, but the shape of the storage element 10 is not limited to a rectangular parallelepiped, and may be a cylinder, a long cylinder, or a polygonal column other than a rectangular parallelepiped. Or a laminate type storage element.

As shown in FIG. 1, the storage element 10 includes a container 100, a positive electrode terminal 200, and a negative electrode terminal 300. As shown in FIG. 2, an electrode assembly 400, a positive electrode current collector 500, and a negative electrode current collector 600 are accommodated inside the container 100.

Gaskets and the like are disposed between the lid 110 and the positive electrode terminal 200 and between the lid 110 and the positive electrode current collector 500 in order to enhance the insulation and air tightness, but are omitted in the figure. Is shown. The same applies to the negative electrode side. Although an electrolytic solution (non-aqueous electrolyte) is enclosed in the inside of the container 100, illustration is abbreviate | omitted. The type of the electrolyte is not particularly limited as long as it does not impair the performance of the storage element 10, and various types can be selected. In addition to the above components, a spacer disposed laterally of the positive electrode current collector 500 and the negative electrode current collector 600, a gas discharge valve for releasing the pressure when the pressure in the container 100 is increased, or An insulating film or the like that wraps the electrode body 400 or the like may be disposed.

The container 100 is configured of a container body 111 having a rectangular cylindrical bottom and a bottom, and a lid 110 which is a plate-like member for closing the opening of the container body 111. The container 100 is configured such that the lid 110 and the container body 111 are welded or the like after the electrode body 400 and the like are accommodated therein, and the inside can be sealed. The material of the lid 110 and the container body 111 is not particularly limited, and may be a weldable metal such as stainless steel, aluminum, or an aluminum alloy, but a resin may also be used.

The electrode assembly 400 includes a positive electrode plate, a negative electrode plate, and a separator, and is a storage element (power generation element) capable of storing electricity. The positive electrode plate is an electrode plate in which a positive electrode active material layer is formed on a positive electrode base material layer which is a long strip-like current collector foil made of aluminum, aluminum alloy or the like. The negative electrode plate is an electrode plate in which a negative electrode active material layer is formed on a negative electrode base material layer which is a long strip-like current collector foil made of copper, copper alloy or the like. As the current collector foil, known materials such as nickel, iron, stainless steel, titanium, sintered carbon, conductive polymer, conductive glass, Al-Cd alloy and the like can be used appropriately. As the positive electrode active material and the negative electrode active material used for the positive electrode active material layer and the negative electrode active material layer, known materials can be appropriately used as long as they are active materials capable of inserting and extracting lithium ions. The separator can be a microporous sheet made of resin or a non-woven fabric.

In the electrode body 400, a separator is disposed and wound between a positive electrode plate and a negative electrode plate. Specifically, in the electrode body 400, the positive electrode plate and the negative electrode plate are wound so as to be mutually shifted in the direction of the winding axis (virtual axis parallel to the X-axis direction in this embodiment) via the separator. ing. The positive electrode plate and the negative electrode plate have a portion (active material layer non-forming portion) where the active material is not applied (the active material layer is not formed) and the base material layer is exposed at the end in the shifted direction. Have.

That is, the electrode assembly 400 has stacked electrode plates (a positive electrode plate and a negative electrode plate). The electrode body 400 has a positive electrode focusing portion 410 in which an active material layer non-forming portion of the positive electrode plate is stacked and bundled at one end portion in the winding axis direction (the end portion in the X axis plus direction). The electrode body 400 has a negative electrode focusing portion 420 in which the active material layer non-forming portion of the negative electrode plate is stacked and bundled at the other end portion in the winding axis direction (the end portion in the X axis minus direction). The thickness of the active material layer non-forming portion (current collecting foil) of the positive electrode plate and the negative electrode plate is about 5 μm to 20 μm, and by bundling about 30 to 40 sheets, the positive electrode focusing portion 410 and the negative electrode focusing portion 420 It is formed. In the present embodiment, an oval shape is illustrated as the cross-sectional shape of the electrode body 400, but it may be circular or elliptical.

The positive electrode terminal 200 is an electrode terminal electrically connected to the positive electrode plate of the electrode body 400, and the negative electrode terminal 300 is an electrode terminal electrically connected to the negative electrode plate of the electrode body 400. That is, positive electrode terminal 200 and negative electrode terminal 300 lead the electricity stored in electrode assembly 400 to the external space of storage element 10, and the electricity in the internal space of storage device 10 for storing electricity in electrode assembly 400. It is a metal electrode terminal for introducing The positive electrode terminal 200 and the negative electrode terminal 300 are attached to a lid 110 disposed above the electrode assembly 400. Specifically, as shown in FIG. 3, in the positive electrode terminal 200, the protrusion 210 is inserted into the through hole 110a of the lid 110 and the opening 511 of the positive electrode current collector 500 and caulking is performed. It is fixed to the lid 110 together with the current collector 500. The same applies to the negative electrode terminal 300.

The positive electrode current collector 500 is disposed between the positive electrode focusing portion 410 of the electrode body 400 and the side wall of the container body 111, and has conductivity and rigidity electrically connected to the positive electrode terminal 200 and the positive electrode plate of the electrode body 400. And a member provided with The negative electrode current collector 600 is disposed between the negative electrode focusing portion 420 of the electrode body 400 and the sidewall of the container body 111, and has conductivity and rigidity electrically connected to the negative electrode terminal 300 and the negative electrode plate of the electrode body 400. And a member provided with

Specifically, the positive electrode current collector 500 and the negative electrode current collector 600 are arranged in a bent state along the side wall and the lid 110 from the side wall of the container body 111 to the lid 110. It is a member. The positive electrode current collector 500 and the negative electrode current collector 600 are fixedly connected (joined) to the lid 110. The positive electrode current collector 500 and the negative electrode current collector 600 are fixedly connected (joined) to the stacked electrode plates of the electrode assembly 400, that is, the positive electrode focusing portion 410 and the negative electrode focusing portion 420. With this configuration, the electrode assembly 400 is held (supported) in a state of being suspended from the lid 110 by the positive electrode current collector 500 and the negative electrode current collector 600, and shaking due to vibration or impact is suppressed.

Although the material of the positive electrode current collector 500 is not limited, it is formed of aluminum or an aluminum alloy as in the case of the positive electrode base layer of the electrode assembly 400. The material of the negative electrode current collector 600 is not limited, but is made of copper or a copper alloy as in the case of the negative electrode base layer of the electrode assembly 400.

[Description of configuration around caulking joint 20]
As shown in FIG. 2, the positive electrode current collector 500 is joined to the positive electrode focusing portion 410 of the electrode assembly 400 at a plurality of caulking joints 20. The negative electrode current collector 600 is joined to the negative electrode focusing portion 420 of the electrode assembly 400 at a plurality of caulking junctions 30. The schematic configuration around the caulking joints 20 and 30 will be described below with reference to FIG. Since the positive electrode side caulking junction 20 and the negative electrode caulking portion 30 have the same configuration, the configuration around the positive electrode caulking portion 20 will be described below. The description of the configuration around the caulking joint 30 is omitted.

FIG. 4 is a cross-sectional view showing a configuration in which positive electrode current collector 500 according to the present embodiment is joined to positive electrode focusing portion 410 of electrode assembly 400. Specifically, this figure shows the configuration in the case where the positive electrode current collector 500 and the positive electrode focusing portion 410 shown in FIG. 2 are cut along the YZ plane passing through the caulking joint portion 20.

As shown in FIGS. 3 and 4, the positive electrode current collector 500 includes a terminal connection portion 510 and two electrode connection portions extended from both end portions of the terminal connection portion 510 in the Y-axis direction in the Z-axis negative direction. And 520. FIG.

The terminal connection portion 510 is a base of the positive electrode current collector 500 connected (joined) to the positive electrode terminal 200. That is, the terminal connection portion 510 is a flat plate-like portion disposed on the positive electrode terminal 200 side (upper side, Z-axis plus direction) of the positive electrode current collector 500, and is electrically and mechanically connected to the positive electrode terminal 200. .

The electrode connection portion 520 is a leg portion of the positive electrode current collector 500 connected (joined) to the electrode body 400. That is, the electrode connection portion 520 is a portion disposed on the electrode body 400 side (lower side, Z-axis negative direction side) of the positive electrode current collector 500, and is electrically and mechanically connected to the electrode body 400. Specifically, the electrode connection portion 520 is a long and flat portion extending in the Z-axis direction, and in two positive flat focusing portions of the positive electrode focusing portion 410 of the electrode assembly 400, two electrode flat portions are provided. The electrode connection parts 520 are respectively joined.

As shown in FIG. 4, a backing plate 700 is disposed inside the positive electrode focusing portion 410, and the electrode connection portion 520, the positive electrode focusing portion 410, and the backing plate 700 are mechanically joined to form four (2 Two crimped joints 20 are formed on each of the two electrode connections 520. That is, the electrode connection portion 520 and the positive electrode focusing portion 410 are provided with the caulking joint portion 20 which is fitted to each other in a concavo-convex structure in which either one protrudes toward the other. Specifically, caulking joint portion 20 is formed with a concavo-convex structure in which electrode connection portion 520 and positive electrode focusing portion 410 project in the positive Y-axis direction or the negative Y-axis direction (hereinafter also referred to as the first direction). The electrode connecting portion 520 and the positive electrode focusing portion 410 are fitted and joined to each other. The crimped joint 20 can be formed by caulking and plastically deforming the electrode connection portion 520, the positive electrode focusing portion 410, and the backing plate 700 (specifically, by performing a crimped crimped joint).

The electrode connection portion 520 (positive electrode current collector 500) is an example of a first member, and the positive electrode focusing portion 410 (electrode assembly 400) is an example of a second member disposed on the first direction side of the first member. is there. The electrode connection portion 520 (positive electrode current collector 500) and the positive electrode focusing portion 410 (electrode assembly 400) are examples of a conductive member disposed in the path of the current flowing through the electrode assembly 400. The current flowing through the electrode body 400 is a charging current of the storage element 10 or a discharge current (main current) of the storage element 10. The current path is a current path between the electrode body 400 and the positive electrode terminal 200 and the negative electrode terminal 300 or a current path from the positive electrode terminal 200 and the negative electrode terminal 300 to the outside of the storage element 10.

The caulking joint 20 is a cylindrical projecting portion, and two caulking joints 20 are disposed so as to protrude toward each other at positions facing each other. That is, the first member and the second member have two (two pairs) of a pair of caulking joints 20 at opposite positions in the Y-axis direction. A detailed description of the configuration of the caulking joint 20 will be described later.

The backing plate 700 is a cover that is disposed at a position sandwiching the positive electrode focusing portion 410 with the electrode connection portion 520 and that protects the positive electrode focusing portion 410. Specifically, the backing plate 700 is a rectangular and flat plate-like member extending in the Z-axis direction along the positive electrode focusing portion 410, and in the state before bonding, the thickness is uniform. There is. The material of the backing plate 700 is not particularly limited, but, like the positive electrode base layer of the electrode assembly 400, it is a metal member formed of aluminum or an aluminum alloy. Similarly, a backing plate is disposed on the negative electrode side, and the material of the backing plate on the negative electrode side is not particularly limited, but is made of copper or copper alloy as in the case of the negative electrode base layer of the electrode assembly 400. It is a metal member.

[Description of the configuration of the caulking joint 20]
Next, the configuration of the caulking joint 20 will be described in more detail. FIG. 5 is a perspective view and a cross-sectional view showing the configuration of the crimp joint 20 according to the present embodiment. Specifically, (a) of FIG. 5 is a perspective view of the crimped joint 20 on the Y-axis negative direction side shown in FIG. 4 as viewed from the caulking plate 700 side (projecting side). (B) of FIG. 5 is a cross-sectional view showing a configuration when the crimped joint 20 shown in (a) of FIG. 5 is cut along the YZ plane including the Vb-Vb line. The crimped joint 20 on the Y-axis plus direction side shown in FIG. 4 has the opposite direction of the crimped joint 20 on the Y-axis minus direction side and the Y-axis direction, but the configuration is the same. Do.

As shown in FIG. 5, the caulking joint 20 is a circular top joint in a top view that protrudes in the Y-axis plus direction. In the same figure, the top view is viewed from the Y-axis plus direction. The top view circular shape means having a circular shape when viewed from the Y-axis plus direction. Specifically, in the caulking joint portion 20, the electrode connection portion 520 of the positive electrode current collector 500 protrudes toward the positive electrode focusing portion 410 of the electrode assembly 400, and the bottomed substantially cylindrical portion of the electrode connection portion 520 is It has a shape of a concavo-convex structure protruding toward the bottomed substantially cylindrical portion of the positive electrode focusing portion 410. In the caulking joint portion 20, the positive electrode focusing portion 410 protrudes toward the backing plate 700, and the bottomed substantially cylindrical portion of the positive electrode focusing portion 410 protrudes toward the bottomed substantially cylindrical portion of the backing plate 700. It can be said that it is the shape of the concavo-convex structure.

In such a configuration, the electrode connection portion 520, the positive electrode focusing portion 410, and the backing plate 700 project from the first protrusion (the current collector first protrusion 521, the electrode) in the first direction in the caulking joint 20. Body first projecting portion 411 and contact plate first projecting portion 701). The first direction is the direction in which the first protrusion protrudes, that is, the direction from the electrode connection portion 520 toward the backing plate 700, and in FIG. 5, is the Y-axis plus direction. The said 1st protrusion part has the 2nd protrusion (The collector 2nd protrusion part 522 and the electrode body 2nd protrusion part 412) which protrudes in the 2nd direction which cross | intersects a 1st direction. In the present embodiment, the second direction is a direction orthogonal to the first direction, and is all directions in the XZ plane (both sides in the Z-axis direction in FIG. 5).

Specifically, the electrode connection portion 520 has a current-collector first projecting portion 521 that protrudes toward the positive electrode focusing portion 410 in the first direction (the Y-axis plus direction). The current-collector first protrusion 521 is a bottomed substantially cylindrical convex portion in which the surface on the positive electrode focusing portion 410 side of the electrode connection portion 520 protrudes toward the positive electrode focusing portion 410. In other words, the surface of the current-collector first protrusion 521 opposite to the positive electrode focusing portion 410 of the electrode connection portion 520 has a concaved shape toward the positive electrode focusing portion 410 side. That is, the current-collector first projecting portion 521 is formed with a current-collector first concave portion 523 in which the electrode connection portion 520 is recessed in the first direction. The current collector first concave portion 523 is a circular concave portion formed on the back side of the current collector first projecting portion 521 in a top view. The current collector first concave portion 523 is an example of the first concave portion in which the first member is concaved in the first direction.

In the current-collector first projecting portion 521, a current-collector second concave portion 524 recessed from the current-collector first concave portion 523 in the first direction is formed. The current collector second concave portion 524 is a concave portion in a top view circular shape formed by recessing the central portion of the bottom portion positioned on the first direction side of the current collector first projecting portion 521 in the first direction. As a result, a current collector first portion 525 which is a thin portion is formed on the current collector first protrusion 521 on the first direction side of the current collector second concave portion 524. The current collector first portion 525 is a thin-walled portion in a circular shape (disk shape) in a top view formed in the central portion of the bottom portion of the current collector first concave portion 523. The current collector second recess 524 is an example of a second recess recessed from the first recess in the first direction. The current collector first portion 525 is an example of a first portion disposed on the first direction side of the second recess.

The thickness of the current-collector first portion 525 is smaller than the depth of the current-collector second recess 524. That is, the thickness D1 of the current-collector first portion 525 in the first direction is smaller than the depth D2 of the current-collector second recess 524 in the first direction. The minimum value of thickness D1 of current-collector first portion 525 may be smaller than the maximum value of depth D2 of current-collector second recess 524, but the maximum value of thickness D1 of current-collector second portion 525 is Preferably, it is smaller than the minimum value of the depth D2 of the current-collector second concave portion 524.

The thickness of the current-collector second portion 525 is smaller than the thickness of the current-collector second portion 526 disposed on the second direction side intersecting the first direction of the current-collector first recess 523. The current collector second portion 526 is a substantially cylindrical portion that forms the side wall of the current collector first protrusion 521. That is, the thickness D1 of the current-collector first portion 525 in the first direction is smaller than the thickness D3 of the current-collector second portion 526 in the second direction. The minimum value of thickness D1 of current collector first portion 525 may be smaller than the maximum value of thickness D3 of current collector second portion 526, but the maximum value of thickness D1 of current collector first portion 525 is It is preferable to be smaller than the minimum value of the thickness D3 of the current collector second portion 526. The current collector second portion 526 is an example of a second portion disposed on the second direction side intersecting the first direction of the first recess.

The current-collector first protrusion 521 has a current-collector second protrusion 522 that protrudes in the second direction. The current collector second projection 522 has an annular top view that protrudes from the end on the first direction side of the current collector first projection 521 toward the electrode body first projection 411 along the entire circumference. It is a site.

The positive electrode focusing portion 410 is disposed on the first direction side (Y-axis plus direction side) of the current-collector first projecting portion 521 of the electrode connection portion 520, and the electrode body that protrudes in the first direction toward the contact plate 700. One projecting portion 411 is provided. The electrode body first projecting portion 411 is a bottomed substantially cylindrical convex portion in which the surface of the positive electrode focusing portion 410 on the backing plate 700 side protrudes toward the backing plate 700. In other words, the electrode body first projecting portion 411 has a shape in which the surface of the positive electrode focusing portion 410 on the electrode connection portion 520 side is recessed toward the backing plate 700 side. That is, in the electrode body first projecting portion 411, an electrode body first concave portion 413 in which the positive electrode focusing portion 410 is recessed in the first direction is formed. The electrode body first concave portion 413 is a circular concave portion formed on the back side of the electrode body first projecting portion 411 in a top view.

The electrode body first projecting portion 411 has an electrode body second portion 414 which is a disk-like bottom portion located in the first direction side, and an electrode body second portion 415 which is a substantially cylindrical side wall. The electrode body first portion 414 is a portion disposed on the first direction side of the current collector first portion 525, and the electrode body second portion 415 has an entire periphery along the outer periphery of the current collector second portion 526. It is a part arranged at That is, as viewed from the first direction, the end portion on the first direction side of the current collector second portion 526 is disposed inward of the end portion on the first direction side of the electrode body second portion 415. In other words, when viewed from the first direction, the current collector first concave portion 523 has the end on the first direction side disposed inward of the outer edge of the first direction end of the electrode body first protrusion 411. It is done.

The electrode body first protrusion 411 has an electrode body second protrusion 412 that protrudes in the first direction and the second direction. The electrode body second projection 412 extends from the end of the electrode body first projection 411 on the first direction side to the contact plate first projection 701 and the contact plate second projection 702 described later over the entire circumference. It is a part of the top view annular shape which protruded. The electrode body first protruding portion 411 is an example of a first convex portion in which the second member protrudes in the first direction.

The contact plate 700 is disposed on the first direction side (the Y-axis plus direction side) of the electrode body first projecting portion 411 of the positive electrode focusing portion 410, and protrudes in the first direction away from the positive electrode focusing portion 410. It has a plate first protrusion 701. The first plate projecting portion 701 is a bottomed substantially cylindrical convex portion whose surface on the opposite side to the positive electrode focusing portion 410 of the backing plate 700 protrudes on the opposite side to the positive electrode focusing portion 410. In other words, the contact plate first protrusion 701 has a shape in which the surface on the positive electrode focusing portion 410 side of the backing plate 700 is recessed toward the opposite side to the positive electrode focusing portion 410. That is, the contact plate first projection 701 is formed with a contact plate first concave portion 703 in which the contact plate 700 is recessed in the first direction. The target plate first concave portion 703 is a circular shaped concave portion in a top view formed on the back side of the target plate first protrusion 701.

The first plate projecting portion 701 includes a second plate portion 704 which is a disk-shaped bottom portion positioned in the first direction and a second plate portion 705 which is a substantially cylindrical side wall. The first plate portion 704 is a portion disposed on the first direction side of the first electrode portion 414, and the second plate portion 705 is disposed along the entire outer circumference of the second electrode portion 415. Site to be That is, as viewed from the first direction, the end on the first direction side of the electrode body second portion 415 is disposed inward of the end on the first direction side of the contact plate second portion 705. In other words, when viewed from the first direction, the electrode body first concave portion 413 has the end on the first direction side disposed inward of the outer edge of the first direction end of the contact plate first projecting portion 701. ing.

The abutment plate first projecting portion 701 has an abutment plate second projecting portion 702 having an annular top view and projecting toward the first direction at an end portion on the first direction side.

The current collector first protrusion 521, the electrode body first protrusion 411, the contact plate first protrusion 701, the current collector second protrusion 522, the electrode second protrusion 412 and the contact plate second protrusion 702 The protruding direction is not limited to the above direction. It may be a direction inclined from the above direction, and the projecting shape is not limited to the above. The current collector second protrusion 522 may also protrude in the first direction. The electrode body second protrusion 412 may not protrude in the first direction. The target plate second protrusion 702 may not protrude in the first direction.

The second plate projection portion 702 may protrude in the second direction from the first direction end of the first plate projection portion 701. However, after the joining operation, the caulking joint portion 20 is a die of a joining tool. In order to make it easy to remove it, it is preferable that the contact plate second projecting portion 702 be configured not to protrude in the second direction. Similarly, in order to make the crimped joint 20 easier to remove from the die, the width in the second direction (the width in the Z-axis direction in FIG. 5) of the contact plate first protrusion 701 and the contact plate second protrusion 702 is It is preferable to become smaller toward the tip (end on the first direction side). Similarly, in order to facilitate removal of the crimped joint 20 from the punch, the width in the second direction (the width in the Z-axis direction in FIG. 5) of the current collector first concave portion 523 and the current collector second concave portion 524 is It is preferable to be smaller toward (the end on the first direction side).

[4 Description of effect]
As described above, according to power storage device 10 as a power storage device according to the embodiment of the present invention, electrode connection portion 520 (first member) of positive electrode current collector 500 and positive electrode focusing portion 410 (electrode member 400) In the crimped joint portion 20 formed on the two members, the electrode body first projecting portion 411 (first convex portion) in which the positive electrode focusing portion 410 protrudes in the first direction, and the electrode connecting portion 520 are recessed in the first direction The current collector first concave portion 523 (first concave portion) and the current collector second concave portion 524 (second concave portion) recessed from the current collector first concave portion 523 in the first direction are included. That is, in the caulking joint portion 20, when the electrode body first projecting portion 411 is formed in the positive electrode focusing portion 410 and the current collector first concave portion 523 is formed in the electrode connecting portion 520, the current collector first portion is formed. A current collector second recess 524 is formed in the one recess 523. As described above, by forming the current collector second concave portion 524 in the current collector first concave portion 523 at the time of caulking bonding, the portion which was at the position of the current collector second concave portion 524 becomes the current collector second portion. It spreads out of the recess 524 and the joint is compressed. As a result, the bonding strength of the caulking joint 20 can be improved, and the bonding strength of the two caulked members (the positive electrode current collector 500 and the electrode assembly 400) can be improved.

In the caulking joint portion 20, the current collector first concave portion 523 has an end on the first direction side, as viewed from the first direction, within the outer edge of the first direction end of the electrode body first projecting portion 411. It is arranged in the direction. That is, at the time of caulking bonding, the current collector first concave portion 523 is formed inside the electrode body first projecting portion 411. As a result, the portion at the current collector first concave portion 523 can be expanded to the outside of the current collector first concave portion 523 with a relatively small force, and the bonding portion can be pressed, so that the caulking bonding is relatively easy. The bonding strength of the portion 20 can be improved.

In the caulking joint portion 20, the electrode connection portion 520 includes the current collector first portion 525 (first portion) disposed on the first direction side of the current collector second concave portion 524, and the current collector first portion The thickness of 525 is smaller than the depth of the current collector second recess 524. That is, until the thickness of the current-collector first portion 525 on the first direction side of the current-collector second concave portion 524 in the electrode connection portion 520 becomes smaller than the depth of the current-collector second concave portion 524, The part 525 is pressed. As a result, the current collector first portion 525 located at the position of the current collector second concave portion 524 spreads to the outside of the current collector second concave portion 524 and the joint portion is compressed, so that the caulking joint portion 20 is joined. The strength can be improved.

In the caulking joint portion 20, the electrode connection portion 520 has a current collector second portion 526 (second portion) disposed on the second direction side intersecting the first direction of the current collector first concave portion 523; The thickness of the current-collector first portion 525 is smaller than the thickness of the current-collector second portion 526. That is, the thickness of the current-collector first portion 525 on the first direction side of the current-collector second concave portion 524 in the electrode connection portion 520 corresponds to the current-collector second portion on the second direction side of the current-collector first concave portion 523. The current collector first portion 525 is pressed to a thickness smaller than 526. As a result, the current collector first portion 525 located at the position of the current collector second concave portion 524 spreads to the outside of the current collector second concave portion 524 and the joint portion is compressed, so that the caulking joint portion 20 is joined. The strength can be improved.

Since the electrode connection portion 520 and the positive electrode focusing portion 410 are conductive members disposed in the path of the main current, there is a possibility that the performance of the storage element 10 may be degraded due to the decrease in bonding strength. For this reason, the effect by the joint strength improvement of the electrode connection part 520 and the positive electrode focusing part 410 is large.

Generally, when two conductive members are crimped and joined, the contact area tends to be smaller than joining such as ultrasonic welding, but the electrode connection portion 520 and the positive electrode focusing portion 410 have main current Since it is a flowing part, when the contact area decreases, the conduction resistance increases. Therefore, by forming the current collector second concave portion 524 in the caulking joint portion 20 and widening the joint portion to the outside, the contact area can be increased, and an increase in current-carrying resistance can be suppressed.

By performing two-step (double) caulking, it is possible to form two-step concave portions (current collector first concave portion 523 and current collector second concave portion 524), but in this case, the positive electrode focusing portion 410 and the backing plate Since the two-step convex portion is formed in 700, the protruding height of the caulking joint becomes high. For this reason, compared with the case where two-step caulking bonding is performed, the caulking bonding portion 20 in the present embodiment can suppress the protruding height to a low level, and can achieve space saving.

The negative electrode current collector 600 side also has the same configuration as that of the positive electrode current collector 500 side, so that the same effect can be obtained.

[Description of Modification of Fifth Embodiment]
(Modification 1)
Next, a first modification of the above embodiment will be described. FIG. 6 is a cross-sectional view showing the configuration of a crimp joint 20 a according to a first modification of the present embodiment. The figure is a figure corresponding to (b) of FIG.

As shown in FIG. 6, the caulking joint portion 20a in this modification has a current collector first projecting portion 521a in place of the current collector first projecting portion 521 of the caulking joint portion 20 in the above embodiment. ing. The current-collector first projecting portion 521 a is the current-collector first concave portion 523, the current-collector second concave portion 524, the current-collector second portion 525, and the current collector of the current-collector first protruding portion 521 in the above embodiment. In place of the second body portion 526, a current collector first concave portion 523a, a current collector second concave portion 524a, a current collector first portion 525a, and a current collector second portion 526a are provided. The other configuration of this modification is the same as that of the above embodiment, and the detailed description will be omitted.

Specifically, a current collector second concave portion 524 a having a depth greater than that of the current collector second concave portion 524 in the above-described embodiment is formed in the current collector first projecting portion 521 a. That is, the current collector second concave portion 524a is formed to be recessed in the first direction from the Y axis negative direction side with respect to the central position of the current collector first concave portion 523a in the Y axis direction. As a result, on the first direction side of the current collector second concave portion 524a, the current collector first portion 525a in a circular shape (disk shape) in a top view larger in diameter than the current collector first portion 525 in the above embodiment. Is arranged. A substantially cylindrical current collector second portion 526a is disposed on the second direction side of the current collector second concave portion 524a. Similar to the above embodiment, the thickness D1 of the current-collector first portion 525a in the first direction is smaller than the depth D2 of the current-collector second recess 524a in the first direction, and the current-collector second portion 526a Is smaller than the thickness D3 in the second direction of

As described above, according to the crimp joint portion 20a according to the present modification, the same effect as that of the above embodiment can be obtained. In particular, in the present modification, by forming the current collector second concave portion 524 a having a deep depth, the bonding strength of the crimped joint portion 20 can be improved.

(Modification 2)
Next, a second modification of the above embodiment will be described. FIG. 7 is a cross-sectional view showing the configuration of a crimp joint portion 20b according to a second modification of the present embodiment. The figure is a figure corresponding to (b) of FIG.

As shown in FIG. 7, the caulking joint portion 20 b in this modification is a current collector in place of the current collector first projecting portion 521 and the electrode body first projecting portion 411 of the caulking joint portion 20 in the above embodiment. It has the 1st protrusion part 521b and the electrode body 1st protrusion part 411b. The current-collector first protrusion 521 b is a convex portion in which the electrode connection portion 520 protrudes in the first direction, and includes a current-collector third protrusion 527 protruding in the first direction. The electrode body first projecting portion 411 b is a convex portion in which the positive electrode focusing portion 410 projects in the first direction, and includes an electrode body third projecting portion 416 projecting in the first direction. The other configuration of this modification is the same as that of the above embodiment, and the detailed description will be omitted.

As described above, each of the current-collector first protrusion 521 b and the electrode body first protrusion 411 b has a two-step protrusion. The first-stage convex portion of the current-collector first projecting portion 521b is an example of a second convex portion in which the first member protrudes in the first direction, and the second-stage convex portion (current-collector third projecting portion 527) is an example of the 3rd convex part which protruded in the 1st direction from the 2nd convex part.

As described above, the crimp joint portion 20b according to the present modification has the same effect as that of the above-described embodiment. In particular, in the present modified example, in the crimped joint 20 b, the current-collector first projecting portion 521 b has a two-step convex portion. Thereby, a two-stage interlock is applied between the electrode connection portion 520 and the positive electrode focusing portion 410, and the bonding strength of the crimped joint portion 20b can be improved. Since the electrode body first protrusion 411b also has a two-step convex portion, a two-step interlock is also applied between the positive electrode focusing portion 410 and the backing plate 700 to further improve the bonding strength of the caulking joint 20b. it can.

In the present modification, at least one of the current-collector first protrusion 521 b and the electrode body first protrusion 411 b may have a two-step protrusion. That is, the electrode body first projecting portion 411b may not have the two-step convex portion, and the current collector first projecting portion 521b may not have the two-step convex portion.

(Other modifications)
As mentioned above, although the electrical storage element as an electrical storage apparatus which concerns on embodiment of this invention and its modification was demonstrated, this invention is not limited to this embodiment and its modification. That is, it should be understood that the embodiment disclosed this time and the modification thereof are illustrative in all points and not restrictive. The scope of the present invention is indicated not by the above description but by the claims, and is intended to include all the modifications within the meaning and scope equivalent to the claims.

In the crimped joint portion 20 of the above-described embodiment and the modification, an interatomic bond may be formed between the current-collector

first portion

525, 525a and the electrode body first portion 414. That is, at the time of current collecting and caulking, the oxide film present on the surface of the current collector first portion 525 is broken to expose a new metal surface, and an interatomic bond is formed with the electrode body first portion 414. Ru. Thereby, the bonding strength of the crimped joint 20 can be further improved.

In the above-mentioned embodiment and its modification, it was decided that a pair of caulking joints are arranged at mutually opposing positions. However, the crimped joints do not have to be arranged at opposite positions. The number of crimped joints is not particularly limited, and any number of crimped joints may be formed in the electrode connection 520. The number of electrode connection portions 520 is not limited, and the positive electrode current collector 500 may have only one electrode connection portion 520, and has three or more electrode connection portions 520. It may be good. When the number of the electrode connection portions 520 is one, since the die and the punch can be easily disposed on both sides of the electrode connection portion 520, the caulking bonding portion can be easily formed.

In the above embodiment and its modification, the positive electrode current collector 500 has a crimp joint formed on both of the two electrode connection parts 520, but only one of the electrode connection parts 520 is formed. A configuration in which a caulking joint is formed may be used. In the storage element, the bonding portion is formed on both of the positive electrode current collector 500 and the negative electrode current collector 600. However, the bonding portion is formed on only one of the positive electrode current collector 500 and the negative electrode current collector 600. May be formed.

In the above-described embodiment and its modification, the crimped joint portion protrudes in the Y-axis plus direction or the minus side (Y-axis plus direction in FIGS. 5 to 7). That is, the crimped joint portion is a joint portion of a concavo-convex structure in which the positive electrode current collector 500 protrudes toward the electrode body 400 and the backing plate 700. However, the caulking joint may be a joint of a concavo-convex structure in which the caulking plate 700 and the electrode assembly 400 protrude toward the positive electrode current collector 500. When the cover plate 700 is thicker than the positive electrode current collector 500, this configuration is preferable. The caulking joint may be squeezed in the height direction (Y-axis direction) to have a shape in which the protruding height is lowered.

In the above-mentioned embodiment and its modification, the caulking joint portion has an outer shape in a top view circular shape. However, the external shape of the caulking joint may be an oval shape, an elliptical shape, a polygonal shape, or the like in top view. Similarly, the first concave portion formed in the caulking joint may have an oval shape, an elliptical shape, a polygonal shape, or the like in top view.

In the above-described embodiment and its modification, in the caulking joint portion, the second concave portion having a circular shape in top view is formed in the central portion of the bottom portion of the first concave portion. However, the second recess may be formed at the end of the bottom of the first recess, and the shape is also not particularly limited, and may be oval, elliptical or polygonal in top view It is also good.

In the above-described embodiment and its modification, the caulking joint is formed with one second recess in the first recess. However, the caulking joint may have a plurality of second recesses formed in the first recess, and a third recess may be further formed in the second recess, so that three or more recesses are formed. It may be done.

In the above-mentioned embodiment and its modification, in the caulking joint portion, the thickness of the first portion is smaller than the depth of the second recess and smaller than the thickness of the second portion. However, the thickness of the first part may be larger than the depth of the second recess, or may be larger than the thickness of the second part.

In the above-mentioned embodiment and its modification, the first recess and the second recess of the caulking joint may be formed by one caulking operation or may be divided into a plurality of caulking operations.

In the above-described embodiment and the modification, the electrode assembly 400 is a so-called longitudinally wound winding-type electrode assembly in which the winding axis is parallel to the lid 110. However, the electrode assembly 400 may be a so-called laterally wound winding electrode assembly in which the winding axis is perpendicular to the lid 110. The shape of the electrode body 400 is not limited to the winding type, and may be a stack type in which flat plate-like electrode plates are stacked, or a shape in which electrode plates and / or separators are folded in a bellows shape.

Although the positive electrode current collector 500, the electrode assembly 400, and the backing plate 700 are joined in the above embodiment and its modification, members other than these may be joined together. Alternatively, the pressure plate 700 may not be provided, and the positive electrode current collector 500 and the electrode assembly 400 may be bonded to form a crimped joint.

Although the positive electrode current collector 500 and the electrode assembly 400 are joined only at the caulking joint portion in the above embodiment and the modification thereof, in addition to the joining at the caulking joint portion, the joining by another joining method May be performed. Other joining methods include ultrasonic welding, resistance welding, arc welding, or welding by laser or electron beam irradiation. As described above, by performing bonding by another bonding method in addition to the caulking bonding portion, the bonding strength can be improved and the contact resistance can be reduced.

In the above-mentioned embodiment and its modification, it was decided that one caulking joint is formed independently. However, a plurality of crimped joints may be formed in series. The adjacent portions of two caulking joints may be integrated to form a shape in which two caulking joints are connected (twin point), or a shape in which three or more caulking joints are connected in an integrated manner may be used. . Such a configuration can improve the bonding strength and reduce the contact resistance.

In the above embodiment and its modification, clinching and caulking is exemplified as an example of plastically deforming the positive electrode current collector 500 and the electrode body 400 when the positive electrode current collector 500 and the electrode body 400 are bonded. However, the present invention is not limited to this, and bonding by caulking in a form different from clinching caulking may be used.

In the above embodiment and the modification, the first member is the current collector (the electrode connection portion 520 of the positive electrode current collector 500), and the second member is the electrode body 400 (the positive electrode focusing portion 410). And However, the first member and the second member may be two members disposed in the path of the current flowing through the electrode assembly 400 and joined to each other, and are not limited to the current collector and the electrode assembly 400. When a conductive member such as a lead is disposed between the electrode body 400 and the current collector, the first member and the second member may be the electrode body 400 and the conductive member, or the current collector And it may be the conductive member concerned. When the electrode terminal (the positive electrode terminal 200 or the negative electrode terminal 300) is composed of two members, the first member and the second member may be the two members constituting the electrode terminal. When the current collector (the positive electrode current collector 500 or the negative electrode current collector 600) is composed of two members, the first member and the second member may be the two members that constitute the current collector. Good. The first member and the second member may be an electrode terminal and a current collector. When the container 100 is dropped to the potential of the positive electrode or the negative electrode, the first member and the second member may be the electrode terminal and the container 100, or may be the current collector and the container 100.

In the above embodiment and its modification, the storage device includes only one storage element (that is, the storage device is a storage element), and the first member and the second member are two members included in the storage element. I decided to However, the storage device is a module having a plurality of storage elements or a pack having a plurality of the modules, and the first member and the second member may be two members of the module or the pack. Good. When the first member and the second member are provided in the module, the first member and the second member are a bus bar between the electrode terminal of the storage element and the storage element, and a bus bar connected to the electrode terminal of the storage element And the external terminals of the module, or the two members in the case where these bus bars are formed by two members. When the first member and the second member are provided in the pack, the first member and the second member may be a bus bar between the external terminal of the module and the module and a bus bar connected to the external terminal of the module and the pack It may be an external terminal, or may be two members in the case where these bus bars are formed by two members. When the storage device is provided with a relay or a fuse, the first member and the second member may be a bus bar and a relay, or a bus bar and a fuse. Also in these cases, the configurations of the first member and the second member and the effects thereof are the same as those of the above-described embodiment and the modifications thereof.

Furthermore, the first member and the second member may be two metal members in the module or pack not disposed in the path of the current flowing through the electrode body 400. As the first member and the second member, an end plate disposed at both ends of a plurality of storage elements for sandwiching the plurality of storage elements, and a restraint bar connected to the end plate to restrain the plurality of storage elements are considered. Be Alternatively, as the first member and the second member, an exterior body main body and a lid of an exterior body that accommodates a plurality of power storage elements can be considered. The first member and the second member may be two adjacent casings (two adjacent module cases, two adjacent pack cases, etc.).

The first and second members may not be two metal members but two plates other than metal members such as reinforced plastic in a module or pack. As the first member and the second member, the above-described end plate and restraining bar, the exterior body main body and the lid of the exterior body, and the like can be considered. The first member and the second member may be two adjacent casings (two adjacent module cases, two adjacent pack cases, etc.).

A form constructed by arbitrarily combining the components included in the above embodiment and the modification thereof is also included in the scope of the present invention.

The present invention is applicable to a power storage device provided with a power storage element such as a lithium ion secondary battery.

10

storage element

20, 20a, 20b, 30 caulking joint 400 electrode body 410 positive

electrode focusing portion

411, 411b electrode body first projecting portion 412 electrode body second projecting portion 413 electrode body first concave portion 414 electrode body first portion 415 electrode Body second part 416 electrode body third projecting portion 500 positive electrode current collector 520

electrode connecting portion

521, 521a, 521b current collector first projecting portion 522 current collector second projecting

portion

523, 523a current collector first

concave portion

524 , 524a current collector second

concave portion

525, 525a current collector

first portion

526, 526a current collector second part 527 current collector third projecting portion

Claims

A storage device comprising a storage element, wherein
A first member, and a second member disposed on the first direction side of the first member,
Each of the first member and the second member has a caulking joint formed of a concavo-convex structure protruding in the first direction,
The caulking joint is
A first convex portion in which the second member protrudes in the first direction;
A first recess in which the first member is recessed in the first direction;
And a second recess recessed from the first recess in the first direction.
When viewed from the first direction, the first recess has an end on the first direction side disposed inward of an outer edge of the end on the first direction side of the first protrusion. Power storage device as described in.
The first member has a first portion disposed on the first direction side of the second recess,
The power storage device according to claim 1, wherein a thickness in the first direction of the first part is smaller than a depth in the first direction of the second recess.
The first member includes a first portion disposed on the first direction side of the second recess, and a second portion disposed on the second direction side intersecting the first direction of the first recess. Have
The power storage device according to any one of claims 1 to 3, wherein a thickness of the first part in the first direction is smaller than a thickness of the second part in the second direction.
The caulking joint further comprises:
A second convex portion in which the first member protrudes in the first direction;
The power storage device according to any one of claims 1 to 4, further comprising: a third convex portion protruding from the second convex portion in the first direction.
The storage element has an electrode body,
The power storage device according to any one of claims 1 to 5, wherein the first member and the second member are conductive members disposed in a path of a current flowing through the electrode body.