JP2019029227A - Power storage element - Google Patents

Abstract

To provide a power storage element in which a compressed convex part of a gasket is preferably compressed at the time of caulking, and which has excellent airtightness and watertightness.SOLUTION: A power storage element 1 comprises: a case having a rid plate 2 and a case main body; an axial part 41 penetrating the rid plate 2 and having a caulking part 42 in one end of an axial direction; an insulation plate 5 that is arranged onto a first surface of the rid plate 2, and is interposed between the caulking part 42 and the rid plate 2; and a gasket 6 arranged onto a second surface of the rid plate 2. The gasket 6 includes a compressed convex part 62 at a position where the caulking part 42 is overlapped in the axial direction. The insulation plate 5 includes an energization part 53 pressing the compressed convex part 62 through the rid plate 2 at a position overlapped with the caulking part 42 and the compressed convex part 62 in the axial direction.SELECTED DRAWING: Figure 2

Description

  The present invention relates to an electricity storage device including an insulating plate disposed on one surface of a cover plate and a gasket disposed on the other surface.

  Storage elements such as lithium ion secondary batteries have been used as power sources for mobile devices such as notebook computers and mobile phones. In recent years, it has been used in a wide range of fields such as EV (electric vehicle), HEV (hybrid electric vehicle), and PHEV (plug-in hybrid electric vehicle) power supplies.

In general, in an electric storage element, an electrode body formed by laminating or winding a positive electrode plate and a negative electrode plate via a separator is hermetically accommodated in a case together with an electrolytic solution. The positive electrode terminal and the negative electrode terminal that are electrically connected to the electrode body are provided on the cover plate of the case.
A gasket or an insulating plate is disposed between the case and the terminal and between the case and the current collector.

  In order to improve hermeticity, the electric storage element of Patent Document 1 is configured to insert a sealing member facing the concave portion into a concave portion provided on the surface of the case.

Japanese Patent Laid-Open No. 2006-173902

  An object of this invention is to provide the electrical storage element which has favorable airtightness and watertightness.

  An electricity storage device according to the present invention is disposed on a first surface of a cover plate, a case having a cover plate and a case body, a shaft portion penetrating the cover plate and having a caulking portion at one end in an axial direction. And an insulating plate interposed between the caulking portion and the lid plate, and a gasket disposed on the second surface of the lid plate, wherein the gasket overlaps the caulking portion in the axial direction. The insulating plate presses the compressed convex portion via the lid plate at a position overlapping the crimped portion and the compressed convex portion in the axial direction. There is an urging section to do.

  In the present invention, when one end portion of the shaft portion is caulked, a compressive force is effectively applied to the urging portion provided at a position overlapping with the caulking portion, and the urging portion is provided at a position overlapping with the urging portion. The force almost straight advances to the compressed convex portion, and the compressed convex portion is pressed. Therefore, the to-be-compressed convex part is compressed well, and good air tightness and water tightness are obtained.

It is a perspective view of the electrical storage element which concerns on 1st Embodiment. It is the II-II sectional view taken on the line of FIG. FIG. 3 is a partially enlarged view of FIG. 2. It is sectional drawing of an insulation plate. It is a perspective view of an insulating plate. It is a perspective view of an insulating plate. It is sectional drawing which shows the cover plate of the conventional electrical storage element. It is a microscope picture which shows the cross section when caulking a shaft part when it has a conventional insulating plate. It is a microscope picture which shows the cross section when the shaft part is caulked when it has the insulating plate which concerns on 1st Embodiment. It is a front view which shows the electrical storage module which has an electrical storage element. It is a top view which shows the cover plate of the electrical storage element which concerns on 2nd Embodiment. It is the XII-XII sectional view taken on the line of FIG.

Hereinafter, the present invention will be specifically described with reference to the drawings showing embodiments thereof.
(First embodiment)
1 is a perspective view of a power storage device 1 according to the first embodiment, FIG. 2 is a cross-sectional view taken along the line II-II of FIG. 1, FIG. 3 is a partially enlarged view of FIG. FIG. 5 is a perspective view of the insulating plate 5, and FIG. 6 is a perspective view of the insulating plate 5. Here, the electrical storage element 1 is a lithium ion secondary battery.
The power storage element 1 includes a case 11 having a cover plate 2 and a case body 3, a positive terminal 4, a negative terminal 8, insulating plates 5 and 9, gaskets 6 and 10, current collectors 7 and 12, a rupture valve 20, and an electrode body 21. A positive electrode tab 22 and a negative electrode tab 23.

  The case 11 is made of, for example, a metal such as aluminum, an aluminum alloy, or stainless steel, or a synthetic resin. The case 11 has a rectangular parallelepiped shape and accommodates the electrode body 21 and an electrolytic solution (not shown).

As shown in FIGS. 2 and 3, the positive electrode terminal 4 includes a shaft portion 41 that penetrates the cover plate 2, a caulking portion 42 that caulks one end portion of the shaft portion 41, and a plate provided at the other end of the shaft portion 41. A welding terminal portion 43 is provided. In this embodiment, the shaft portion 41 and the welding terminal portion 43 are formed of the same member, but these are formed of different members, and the positive members 4 are formed by integrating these separate members. Also good. Instead of the welding terminal portion 43, a connecting conductive plate that connects a rivet that forms the shaft portion 41 and a bolt that is spaced apart may be provided at the other end of the shaft portion 41.
The gasket 6 is made of a synthetic resin such as polyphenylene sulfide (PPS) or polypropylene (PP). The gasket 6 includes a plate portion 60 disposed on the outer surface (second surface of claim 1) of the lid plate 2 and a surrounding portion 61 that surrounds the shaft portion 41. On the outer peripheral side of the shaft portion 41 on the outer surface and inner surface of the plate portion 60, a ring-shaped compressed convex portion 62 is provided. The to-be-compressed convex part 62 is not limited to a ring shape, and a plurality of compressed convex parts 62 may be provided at intervals in the circumferential direction.
The current collector 7 has a plate shape, and is made of, for example, aluminum. The current collector 7 is disposed on the inner surface (first surface of claim 1) of the lid plate 2 and has an insertion hole 70 through which one end portion of the shaft portion 41 is inserted. The current collector 7 has a joint portion 71 that joins the positive electrode tab 22 and is disposed outside the other portion (near the lid plate 2) near the center in the longitudinal direction of the lid plate 2. The caulking portion 42 is formed by caulking one end portion of the shaft portion 41 inserted through the insertion hole 70.
The compressed convex portion 62 is provided at a position overlapping the caulking portion 42 in the axial direction of the shaft portion 41.

As shown in FIG. 2, the negative electrode terminal 8 includes a shaft portion 81 that penetrates the cover plate 2, a caulking portion 82 that caulks one end portion of the shaft portion 81, and a plate-like shape provided at the other end of the shaft portion 81. A welding terminal portion 83 is provided. In the present embodiment, the shaft portion 81 and the welding terminal portion 83 are formed by different members, and the negative members 8 are formed by integrating these separate members, but they are formed by the same member. Also good. Instead of the welding terminal portion 83, a connecting conductive plate that connects a rivet that forms the shaft portion 81 and a bolt that is spaced apart may be provided at the other end of the shaft portion 81.
The gasket 10 is made of, for example, PPS or PP, and includes a plate portion 100 disposed on the outer surface of the lid plate 2 and an enclosing portion 101 that surrounds the shaft portion 81. On the outer peripheral side of the shaft portion 81 on the outer surface and inner surface of the plate portion 100, a ring-shaped compressed convex portion 102 is provided. The to-be-compressed convex portions 102 are not limited to a ring shape, and a plurality of compressed convex portions 102 may be provided at intervals in the circumferential direction.
The current collector 12 has a plate shape, and is made of, for example, copper. The current collector 12 is disposed on the inner surface of the lid plate 2 and has an insertion hole 120 through which one end portion of the shaft portion 81 is inserted. The current collector 12 has a joint portion 121 that joins the negative electrode tab 23, which is disposed near the center in the longitudinal direction of the lid plate 2 and outside the other portions (near the lid plate 2). The caulking portion 82 is formed by caulking one end portion of the shaft portion 81 inserted through the insertion hole 120.
The compressed convex portion 102 is provided at a position overlapping the caulking portion 82 in the axial direction of the shaft portion 81.

As shown in FIG. 2, the electrode body 21 includes a main body 210 in which a plurality of positive electrodes and negative electrodes are alternately stacked via separators and formed in a rectangular parallelepiped shape, and a positive electrode extending from the main body 210 toward the lid plate 2. It has a tab 22 and a negative electrode tab 23. The positive electrode tab 22 is joined to the joint portion 71 of the current collector 7. The negative electrode tab 23 is bonded to the bonding portion 121 of the current collector 12.
The electrode body 21 may be obtained by laminating a positive electrode plate and a negative electrode plate via a separator and winding them flat.

The positive electrode plate is obtained by forming a positive electrode active material layer on a positive electrode base foil that is a long strip-shaped metal foil made of aluminum, an aluminum alloy, or the like. The negative electrode plate is obtained by forming a negative electrode active material layer on a negative electrode substrate foil that is a long strip-shaped metal foil made of copper, a copper alloy, or the like. The separator is a microporous sheet made of resin.
As the positive electrode active material used for the positive electrode active material layer or the negative electrode active material layer used for the negative electrode active material layer, any known material can be used as long as it is a positive electrode active material or negative electrode active material capable of occluding and releasing lithium ions. .

Examples of the positive electrode active material include polyanion compounds such as LiMPO ₄ , LiMSiO ₄ , LiMBO ₃ (M is one or more transition metal elements selected from Fe, Ni, Mn, Co, etc.), and lithium titanate. , Spinel compounds such as lithium manganate, lithium transition metal oxides such as LiMO2 (M is one or more transition metal elements selected from Fe, Ni, Mn, Co, etc.), and the like can be used.

Examples of the negative electrode active material include lithium metal and lithium alloy (lithium metal-containing alloys such as lithium-aluminum, lithium-silicon, lithium-lead, lithium-tin, lithium-aluminum-tin, lithium-gallium, and wood alloy). In addition, alloys that can occlude and release lithium, carbon materials (eg, graphite, non-graphitizable carbon, graphitizable carbon, low-temperature calcined carbon, amorphous carbon, etc.), metal oxides, lithium metal oxides (Li ₄ Ti ₅ O _12, etc.), and the like polyphosphoric acid compound.

The burst valve 20 is provided at the center of the lid plate 2. The rupture valve 20 is a safety valve that forms an opening and releases the gas inside the case 11 to reduce the internal pressure when gas is generated inside the case 11 and the internal pressure reaches a constant pressure.
The rupture valve 20 has a rupture portion 200 formed by partially reducing the plate thickness. When the internal pressure of the electricity storage element 1 is increased, the battery element breaks along the breaking portion 200 to form a tongue-like portion, and the portion jumps outward to form an opening in the lid plate 2.

As shown in FIGS. 3 to 6, the insulating plate 5 includes an insertion hole 50, an urging portion 53 having a lever portion 51 and a first contact portion 52, and a storage portion 56. The insulating plate 5 is made of a synthetic resin such as PPS or PP.
The insertion hole 50 is provided at one end of the insulating plate 5 in the longitudinal direction, and the ends of the shaft portion 41 and the surrounding portion 61 are inserted as shown in FIG. The storage portion 56 is provided at the other end of the insulating plate 5, protrudes outward so as to form a step with one end, and stores the joint portion 71 of the current collector 7.

The urging portion 53 is provided at a position overlapping the caulking portion 42 and the compressed convex portion 62 in the axial direction of the shaft portion 41. The first abutting portion 52 of the urging portion 53 is provided on the outer periphery of the insertion hole 50 on the outer surface of the insulating plate 5 and abuts on the inner surface of the lid plate 2. The first contact portion 52 only needs to be able to contact the lid plate 2 and the contact surface may not be flat.
The lever portion 51 of the urging portion 53 is provided on the outer periphery of the groove 54 provided on the outer periphery of the first contact portion 52 and the insertion hole 50 on the inner surface of the lever portion 51, and contacts the outer surface of the current collector 7. 2 contact portions 55. A tapered surface is formed on the outer peripheral side of the second contact portion 55, and the second contact portion 55 protrudes from the other portion of the insulating plate 5 toward the current collector 7.

In the present embodiment, when the one end portion of the shaft portion 41 is caulked to the current collector 7 and the caulking portion 42 is formed, the lever portion 51 receives a compressive force and applies a pressing force to the first contact portion 52. . That is, the lever part 51 exerts an elastic force like a spring washer, and stress concentrates on the first contact part 52 having a small area and a high surface pressure. Therefore, as indicated by the arrows in FIG. 3, the compressive force due to caulking is directed to the first abutment portion 52 so as to effectively and substantially straighten with respect to the compressed convex portion 62.
Since the axial thickness of the first contact portion 52 of the insulating plate 5 is thicker than the axial thickness of the lever portion 51, the rigidity of the portion where the first contact portion 52 is provided is high. Accordingly, the force applied to the first contact portion 52 can be increased, and the force transmitted to the compressed convex portion 62 is increased, so that the compressed convex portion 62 is compressed well and the airtightness and water tightness are improved. Become.

The urging portion 53 is not limited to a case where the urging portion 53 is continuously provided on the outer peripheral side of the insertion hole 50. For example, it may be provided at intervals in the circumferential direction.
The shape of the lever part 51 is not limited to the above case.
The lever part 51 may have only one of the groove 54 and the second contact part 55.
The groove 54 may be formed on the inner surface of the insulating plate 5, and the second contact portion 55 may be formed on the outer surface, that is, upside down with respect to this embodiment.

Similarly to the positive electrode insulating plate 5, the negative electrode insulating plate 9 includes an insertion hole 90, a biasing part 93 having a lever part 91 and a first contact part 92, and a storage part 96.
The shaft portion 81 and one end portion of the surrounding portion 101 are inserted through the insertion hole 90. The urging portion 93 is provided on the outer peripheral side of the insertion hole 90. The first contact portion 92 is provided at a position that overlaps the caulking portion 82 and the compressed convex portion 102.

  When one end portion of the shaft portion 81 is caulked to the current collector 12 and the caulking portion 82 is formed, the lever portion 91 receives a compressive force and applies a pressing force to the first contact portion 92. As a result, the to-be-compressed convex part 102 is compressed well, and the airtightness and watertightness are improved.

Hereinafter, the results of examining the degree of compression of the compressed convex portion when the shaft portion is caulked when the conventional insulating plate is provided and when the insulating plate according to the present embodiment is provided will be described.
FIG. 7 is a cross-sectional view showing a cover plate 13 of a conventional power storage element having a positive insulating plate 14 and a negative insulating plate 15. In the figure, the same parts as those in FIG.
As shown in FIG. 7, both the insulating plate 14 and the insulating plate 15 have flat outer surfaces and inner surfaces on the outer peripheral sides of the shaft portions 41 and 81, and the thickness is uniform.

  FIG. 8 is a photomicrograph showing a cross section when the shaft portion 41 is caulked when the conventional insulating plate 14 is provided. Since the compressed convex portions 62 on both surfaces of the gasket 6 are not compressed, gaps are generated between the outer surface of the gasket 6 and the welding terminal portion 43 and between the inner surface and the cover plate 2 as shown by the enclosure. I understand that.

  FIG. 9 is a photomicrograph showing a cross section when the shaft portion 41 is caulked when the insulating plate 5 of the present embodiment is provided. Since the compressed convex portions 62 on both surfaces of the gasket 6 are compressed and crushed, it can be seen that there are no gaps between the outer surface of the gasket 6 and the welding terminal portion 43 and between the inner surface and the cover plate 2. .

  In Table 1 below, when the insulating plate 5 according to the embodiment is used (Example) and when the conventional insulating plate 14 is used (Comparative Example), the shaft portion 41 is caulked to the current collector 7. The result of calculating | requiring the compression amount of the to-be-compressed convex part 62 is shown. The original height of the compressed convex portion 62 is 0.15 mm. In Examples 1 to 3, the caulking stroke and height are changed as shown in Table 1.

  From Table 1, when Example 1 and Comparative Example 1 in which the caulking stroke and height are substantially the same are compared, Example 1 shows that the amount of compression of both the convex portions 62 to be compressed is larger than Comparative Example 1. I understand. By comparing Examples 1 to 3, it can be seen that increasing the amount of compression of caulking tends to increase the amount of compression of the compressed convex portion.

  As described above, by having the insulating plates 5 and 9 according to the present embodiment, the amount of compression of the compressed convex portions 62 and 102 is increased, no gap is generated between the members, airtightness is improved, and leakage and moisture are increased. It was confirmed that the invasion of water was prevented.

FIG. 10 is a front view showing a power storage module 26 having the power storage element 1.
The power storage module 26 is configured by alternately storing the power storage element 1 and the power storage element 1 a in which the power storage element 1 and the welding terminal portions 43 and 83 are opposite to each other in the vertical direction. Instead of the case 24, the holding member may hold the plurality of power storage elements 1 and 1a.
Bus bar 25 connects adjacent power storage element 1 and welding terminal portion 83 and welding terminal portion 43 of power storage element 1a, and power storage element 1 and power storage element 1a are electrically connected in series.

  When the bus bar 25 is welded to the welding surfaces of the welding terminal portions 43 and 83, an external force acts on the gaskets 6 and 10 in the direction in which the gaskets 6 and 10 are compressed in the axial direction. Since external force does not act in the direction to release the compressed state of the convex portions 62 and 102 to be compressed, the compressed state of the convex portions 62 and 102 to be compressed is maintained even after the bus bar 25 is attached, and airtightness and water tightness are maintained. Can be maintained.

(Second Embodiment)
11 is a plan view showing the cover plate 2 of the energy storage device according to the second embodiment, and FIG. 12 is a cross-sectional view taken along line XII-XII in FIG. In the present embodiment, the current collector and the shaft portion are integrated.
The power storage element has a cover plate 2 and includes a positive electrode side current collector 16, a welding terminal 17, an insulating plate 18, and a gasket 19. 11 and 12, the configuration on the negative electrode side is omitted.

The current collector 16 includes a plate portion 160, a shaft portion 161 that penetrates the lid plate 2, and a caulking portion 162 that is formed at one end of the shaft portion 161.
The gasket 19 includes a plate portion 190 interposed between the current collector 16 and the inner surface of the lid plate 2, a surrounding portion 191 that surrounds the shaft portion 161, and ring-like shapes provided on both surfaces on the outer peripheral side of the surrounding portion 191. Compression target protrusions 192 and 192. The compressed convex portion 192 is not limited to a ring shape, and a plurality of the compressed convex portions 192 may be provided at intervals in the circumferential direction.

  The welding terminal 17 has an insertion hole 171 through which the shaft portion 161 is inserted. The insertion hole 171 has a larger diameter on the outer surface side than the inner surface side, and has a stepped portion 172. By caulking the shaft portion 161 to the step portion 172, the caulking portion 162 is formed, and the current collector 16 is electrically connected to the welding terminal 17.

The insulating plate 18 has an insertion hole 180 through which the surrounding portion 191 is inserted, and is interposed between the outer surface of the cover plate 2 and the inner surface of the welding terminal 17.
The insulating plate 18 also includes a biasing portion 183 having a lever portion 181 and a first contact portion 182.

The urging portion 183 is provided at a position overlapping the caulking portion 162 and the compressed convex portion 192 in the axial direction. The first contact portion 182 is provided on the outer periphery of the insertion hole 180 and contacts the outer surface of the lid plate 2. The first contact portion 182 only needs to be able to contact the lid plate 2 and is not limited to the case where the contact surface is flat.
The lever portion 181 includes a groove 184 provided on the outer periphery of the first contact portion 182 and a second contact portion 185 provided on the outer periphery of the insertion hole 180 and contacting the inner surface of the welding terminal 17. A tapered surface is formed on the outer peripheral side of the second contact portion 185, and the second contact portion 185 protrudes from the other part of the insulating plate 18.

In the present embodiment, when the one end portion of the shaft portion 161 is caulked to the step portion 172 of the welding terminal 17 and the caulking portion 162 is formed, the lever portion 181 receives a compressive force and presses against the first contact portion 182. Is granted. The lever portion 181 exhibits an elastic force like a spring washer, and stress concentrates on the first contact portion 182 having a small area and a high surface pressure. Therefore, the compressive force due to caulking is applied to the compressed convex portion 192 effectively and almost straightly.
Since the axial thickness of the first contact portion 182 of the insulating plate 18 is thicker than the axial thickness of the lever portion 181, the portion where the first contact portion 182 is provided has high rigidity. Therefore, a large force can be applied to the first contact portion 182 and the pressing force applied to the compressed convex portion 192 can be increased.
Therefore, the to-be-compressed convex part 192 is compressed satisfactorily, and airtightness and watertightness are improved.

The urging portion 183 is not limited to a case where the urging portion 183 is continuously provided on the outer periphery of the insertion hole 180. For example, it may be provided at intervals in the circumferential direction.
The shape of the lever portion 181 is not limited to the above case.
The lever portion 181 may have only one of the groove 184 and the second contact portion 185.
The groove 184 may be formed on the inner surface of the welding terminal 17, and the second contact portion 185 may be formed on the outer surface of the lid plate 2, that is, upside down with respect to the present embodiment.

  A power storage element module is configured by electrically connecting a plurality of power storage elements in series. When a bus bar is welded to connect a welding terminal 17 of one storage element and a welding terminal having a different polarity from the welding terminal 17 of another storage element, the gasket 19 is compressed in the axial direction. External force acts in the direction of Since external force does not act in the direction to release the compressed state of the compressed convex portion 192, the compressed state of the compressed convex portion 192 can be maintained and the airtightness and water tightness can be maintained even after the bus bar is attached. .

  As described above, the power storage element is disposed on the first surface of the cover plate, the case having the cover plate and the case main body, the shaft portion penetrating the cover plate and having the caulking portion at one end in the axial direction. An insulating plate interposed between the caulking portion and the lid plate, and a gasket disposed on the second surface of the lid plate, the gasket overlying the caulking portion in the axial direction. There is a compressed convex portion at a wrapping position, and the insulating plate has the compressed convex portion via the lid plate at a position overlapping the caulking portion and the compressed convex portion in the axial direction. It has a biasing part to press.

  According to the above configuration, when one end portion of the shaft portion is caulked, a compressive force is effectively applied to the urging portion provided at a position overlapping with the caulking portion, and the urging portion is provided at a position overlapping with the urging portion. The force advances substantially straight to the compressed convex part, and the compressed convex part is pressed. Therefore, the to-be-compressed convex part is compressed well, and good air tightness and water tightness are obtained.

  In the power storage device described above, the urging portion includes a contact portion that contacts the first surface of the lid plate, and a lever portion that receives a force from the caulking portion and applies a pressing force to the contact portion. And have.

  According to the above configuration, the lever portion receives a compressive force and applies a pressing force to the contact portion. That is, the lever portion exhibits an elastic force like a spring washer, and stress concentrates on the contact portion where the area is small and the surface pressure is high. Therefore, the compressive force by caulking is applied to the compressed convex portion effectively and almost straightly.

  In the power storage element described above, the contact portion and the compressed convex portion overlap in the axial direction.

  According to the said structure, a pressing force can be made to act on a to-be-compressed convex part effectively.

  In the power storage device described above, the insulating plate has an axial thickness at the contact portion larger than an axial thickness at the lever portion.

  According to the said structure, since the rigidity of the part in which the contact part is provided is high, a big force can be provided to a contact part and a pressing force can be made to act on a to-be-compressed convex part effectively.

  The power storage element described above further includes a welding terminal that is integrally formed with the other axial end of the shaft portion and has a welding surface that extends substantially parallel to the surface of the lid plate and to which a bus bar is welded. Is interposed between the welding terminal and the lid plate.

  According to the said structure, when welding a bus-bar to the welding surface of a welding terminal, external force acts on the gasket in the direction which compresses a gasket to an axial direction. Since the external force in the direction to release the compressed state of the compressed convex portion does not act, even after the bus bar is attached to the welding terminal, the compressed state of the compressed convex portion can be maintained and the air tightness and the water tightness can be maintained.

The present invention is not limited to the contents of the above-described embodiments, and various modifications can be made within the scope shown in the claims. That is, embodiments obtained by combining technical means appropriately changed within the scope of the claims are also included in the technical scope of the present invention.
In 1st Embodiment and 2nd Embodiment, although the case where the electrical storage element 1 is a lithium ion secondary battery is demonstrated, the electrical storage element 1 is not limited to a lithium ion secondary battery. The power storage element 1 may be another secondary battery such as a nickel metal hydride battery, a primary battery, or an electrochemical cell such as a capacitor.

DESCRIPTION OF SYMBOLS 1 Power storage element 2 Cover plate 3 Case main body 4 Positive electrode terminal 5, 9, 18 Insulating plate 50, 180 Insertion hole 51, 91, 181 Lever part 52, 92, 182 First contact part 53, 93, 183 Energizing part 54 , 184 Groove 55, 185 Second contact portion 8 Negative electrode terminal 6, 10, 19 Gasket 60, 100, 190 Plate portion 61, 101, 191 Surrounding portion 62, 102, 192 Compressed convex portion 7, 12, 16 Current collector Body 70, 120 Insertion hole 71, 121 Joint part 160 Plate part 11 Case 17 Welding terminal 20 Rupture valve 21 Electrode body 26 Power storage module

Claims (5)

A case having a cover plate and a case body;
A shaft portion that penetrates the lid plate and has a caulking portion at one end in the axial direction;
An insulating plate disposed on the first surface of the lid plate and interposed between the caulked portion and the lid plate;
A gasket disposed on the second surface of the lid plate,
The gasket has a convex portion to be compressed at a position overlapping the caulking portion in the axial direction,
The electrical storage element, wherein the insulating plate has a biasing portion that presses the compressed convex portion via the lid plate at a position overlapping the caulking portion and the compressed convex portion in the axial direction.   The urging portion includes a contact portion that contacts the first surface of the lid plate, and a lever portion that receives a force from the caulking portion and applies a pressing force to the contact portion. The electrical storage element as described in.   The power storage element according to claim 2, wherein the contact portion and the compressed convex portion overlap in the axial direction.   The electric storage element according to claim 2, wherein the insulating plate has an axial thickness at the contact portion larger than an axial thickness at the lever portion. A welding terminal formed integrally with the other axial end of the shaft portion, and having a welding surface extending substantially parallel to the surface of the lid plate and welded to the bus bar;
The power storage device according to claim 1, wherein the gasket is interposed between the welding terminal and the lid plate.