JP7095293B2 - Power storage element - Google Patents

Description

The present invention relates to a power storage element including an insulating member arranged between a container and a current collector.

Conventionally, a power storage element including a container, an electrode terminal, a current collector, and an insulating member is widely known. For example, Patent Document 1 discloses a power storage element including a container, an electrode terminal, a current collector electrically connected to the electrode terminal, and an insulating member arranged between the container and the current collector. Has been done.

Japanese Unexamined Patent Publication No. 2013-93160

By the way, even if an insulating member exists between the current collector and the container, creeping discharge or a tracking phenomenon may occur inside the container. In particular, in a power storage element whose inside of a container has been made denser, since the insulating member becomes smaller, these events are likely to occur, and there is a possibility that it becomes electrically unstable.

An object of the present invention is to provide a power storage element capable of enhancing electrical stability.

In order to achieve the above object, the power storage element according to one aspect of the present invention is an arrangement of an electrode terminal provided in a container, a current collector electrically connected to the electrode terminal, and a container and a current collector. It is provided with an insulating member arranged so as to be accommodated in the direction, and an inwardly recessed step portion is provided on the outer surface of the insulating member.

According to this, since the stepped portion is formed on the outer surface of the insulating member, the creepage distance between the container and the current collector can be extended by the stepped portion. As a result, it is possible to suppress the occurrence of creeping discharge and tracking phenomenon.

Further, assuming that there is no step, if the entire outer surface of the insulating member gets wet with the electrolytic solution, the container and the current collector are electrically connected by the electrolytic solution, and minute discharges and liquid entanglements occur. However, if there is a stepped portion on the outer surface of the insulating member, the creepage distance is extended, so that conduction between the container and the current collector by the electrolytic solution is less likely to occur. Furthermore, since the electrolytic solution is trapped in the stepped portion, the electrolytic solution is less likely to drip to the current collector. From these facts, it is possible to suppress minute discharges and liquid entanglements caused by the electrolytic solution. Therefore, the electrical stability of the power storage element can be improved.

Further, the step portion is recessed inward from the outer surface of the current collector.

According to this, since the stepped portion is recessed inward from the outer surface of the current collector, the creepage distance can be made longer, and the occurrence of creepage discharge and tracking phenomenon can be suppressed more reliably. ..

Further, the outer surface of the insulating member is located outside the outer surface of the current collector.

According to this, since the outer surface of the insulating member is located outside the outer surface of the current collector, the creepage distance can be extended. Further, since the outer surface of the insulating member protrudes from the outer surface of the current collector, the electrolytic solution adhering to the outer surface of the insulating member is less likely to get wet and spread on the outer surface of the current collector. Therefore, it is possible to further suppress minute discharges and liquid entanglements caused by the electrolytic solution, and it is possible to improve the electrical stability of the power storage element.

Further, the step portion is provided at a position facing the container along the side of the container when the container is viewed in a plan view.

Here, in the insulating member, in the portion that does not face the side of the container when the container is viewed in a plan view, since the restriction by the container is small, it is possible to form a large size and extend the creepage distance. On the other hand, in the insulating member, the portion facing the side of the container when the container is viewed in a plan view is largely restricted by the container, and it is difficult to form a large size. Therefore, if the stepped portion is provided at a position facing the container along the side of the container when the container is viewed in a plan view, the creepage distance can be extended by the stepped portion even in a place where there are many restrictions. be. Therefore, the electrical stability of the power storage element can be improved.

Further, the stepped portion is continuously provided with respect to a plurality of sides of the container.

According to this, since the insulating member is provided with the stepped portion at a position continuous with respect to the plurality of sides of the container, the creepage distance at the place where the restriction is large can be extended as a whole. Therefore, the electrical stability of the power storage element can be improved.

Further, the step portion is provided at the end portion on the outer surface of the insulating member on the container side.

Here, when assembling the container, the insulating member, and the current collector to the electrode terminal, the container, the insulating member, and the current collector are attached to the shaft portion in this order with the shaft portion of the electrode terminal facing upward. May be installed. For example, a feeder device is used at the time of assembly, but the insulating member has a flat surface facing upward in contact with the current collector, and the flat surface is attracted by the feeder. Therefore, the wider the flat surface of the insulating member that comes into contact with the current collector, the more stable adsorption is possible, which is preferable. For example, if the step portion is provided at the end portion on the outer surface of the insulating member on the current collector side, the flat surface becomes narrow. On the other hand, as described above, if a step portion is provided at the end portion of the outer surface of the insulating member on the container side, the size of the flat surface can be increased. That is, the feeder device makes it possible to stably adsorb the insulating member, and by extension, the accuracy of the assembly itself can be improved. If the insulating member and other members can be assembled accurately, it is possible to suppress the formation of a gap between them, and it is possible to improve the insulating property and the airtightness. That is, the electrical stability of the power storage element can be improved.

Further, a concave portion into which the container fits is formed on the contact surface of the insulating member with which the container abuts, and the step portion is provided at the end portion on the outer surface of the insulating member on the current collector side and the concave portion. It is located outside.

According to this, since the step portion is provided at the end portion on the outer surface of the insulating member on the current collector side and is located outside the recess, the insulating member is evenly covered by the step portion and the recess. It can be formed thick. If the wall thickness of the insulating member is uniform, the insulating member can be easily molded, and the insulating member with high dimensional accuracy can be realized. If the dimensional accuracy of the insulating member is high, it is possible to improve the electrical stability of the power storage element.

According to the power storage element in the present invention, electrical stability can be enhanced.

It is a perspective view which shows the appearance of the power storage element which concerns on embodiment. It is an exploded perspective view which shows each component by disassembling the power storage element which concerns on embodiment. It is a perspective view which shows the structure of the current collector which concerns on embodiment. It is a perspective view which shows the structure of the lower gasket which concerns on embodiment. It is sectional drawing which shows the structure in the state which the lower gasket, the upper gasket, the current collector and the electrode terminal which concerns on embodiment are attached to a lid body. It is a perspective view which shows the structure of the lower gasket which concerns on the modification of embodiment.

Hereinafter, the power storage element according to the embodiment (and its modification) of the present invention will be described with reference to the drawings. It should be noted that all of the embodiments described below are comprehensive or specific examples. The numerical values, shapes, materials, components, arrangement positions and connection forms of the components, manufacturing processes, order of manufacturing processes, etc. shown in the following embodiments are examples, and are not intended to limit the present invention. Further, among the components in the following embodiments, the components not described in the independent claim indicating the highest level concept are described as arbitrary components. Further, in each figure, the dimensions and the like are not exactly shown.

Further, in the following description and drawings, the arrangement direction of the pair of electrode terminals (positive electrode and negative electrode, the same applies hereinafter) of the power storage element, the arrangement direction of the pair of current collectors, the arrangement direction of the pair of upper gaskets, and the pair of lower parts. The alignment direction of the gaskets, the alignment direction of both ends of the electrode body (a pair of active material layer non-forming portions), the winding axis direction of the electrode body, or the facing direction of the short side surface of the container is defined as the X-axis direction. Further, the opposite direction of the long side surface of the container, the short side direction of the short side surface of the container, the thickness direction of the container, or the arrangement direction of the legs (electrode body connection part) in one current collector is defined as the Y-axis direction. do. Further, the alignment direction between the container body and the lid of the power storage element, the longitudinal direction of the short side surface of the container, or the extension direction of the leg portion (electrode body connection portion) of the current collector is defined as the Z-axis direction. These X-axis directions, Y-axis directions, and Z-axis directions intersect each other (orthogonally in the present embodiment). Further, in the following description, for example, 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 the power storage element 10]
First, with reference to FIGS. 1 and 2, a general description of the power storage element 10 according to the present embodiment will be given. FIG. 1 is a perspective view showing the appearance of the power storage element 10 according to the present embodiment. Further, FIG. 2 is an exploded perspective view showing each component by disassembling the power storage element 10 according to the present embodiment.

The power storage element 10 is a secondary battery capable of charging electricity and discharging electricity, and specifically, is a non-aqueous electrolyte secondary battery such as a lithium ion secondary battery. The power storage element 10 is used, for example, as a power source for automobiles such as an electric vehicle (EV), a hybrid electric vehicle (HEV), or a plug-in hybrid electric vehicle (PHEV), a power source for electronic devices, a power source for power storage, and the like. Further, the power storage element 10 may be mounted on a vehicle such as a gasoline vehicle or a diesel vehicle as a battery for starting an engine. The power 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. Further, the power storage element 10 may be a primary battery that can use the stored electricity without being charged by the user, instead of the secondary battery. Further, the power storage element 10 may be a battery using a solid electrolyte. Further, in the present embodiment, the storage element 10 having a rectangular cuboid shape (square shape) is shown, but the shape of the power storage element 10 is not limited to the rectangular cuboid shape, and is other than the cylindrical shape, the oblong columnar shape, or the rectangular cuboid shape. It may have a polygonal column shape or the like, or it may be a laminated type power storage element.

As shown in FIG. 1, the power storage element 10 includes a container 100, electrode terminals 200 for positive and negative electrodes, and an upper gasket 300 for positive and negative electrodes. Further, as shown in FIG. 2, the lower gasket 400 of the positive electrode and the negative electrode, the current collector 500 of the positive electrode and the negative electrode, and the electrode body 600 are housed inside the container 100. An electrolytic solution (non-aqueous electrolyte) is sealed inside the container 100, but the illustration is omitted. The type of the electrolytic solution is not particularly limited as long as it does not impair the performance of the power storage element 10, and various types can be selected. Further, in addition to the above components, spacers arranged on the sides of the current collector 500 of the positive electrode and the negative electrode, an insulating film for wrapping the electrode body 600, and the like may be arranged.

The container 100 is composed of a container main body 110 having a rectangular tubular shape and a bottom, and a lid 120 which is a plate-shaped member that closes the opening of the container main body 110. Further, the container 100 can be sealed inside by accommodating the electrode body 600 or the like inside and then welding the container body 110 and the lid body 120 or the like. The material of the container body 110 and the lid 120 is not particularly limited, and can be a weldable metal such as stainless steel, aluminum, or an aluminum alloy, but a resin can also be used. Further, the lid 120 has a gas discharge valve 125 that releases the pressure when the pressure inside the container 100 rises, and a liquid injection unit (shown) for injecting the electrolytic solution into the inside of the container 100. ) Etc. are also provided.

The electrode body 600 includes a positive electrode plate, a negative electrode plate, and a separator, and is a power 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-shaped current collecting foil made of aluminum, an 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-shaped current collecting foil made of copper, a copper alloy, or the like. As the current collector foil, known materials such as nickel, iron, stainless steel, titanium, calcined carbon, conductive polymer, conductive glass, and Al—Cd alloy can also be used as appropriate. Further, 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 absorbing and releasing lithium ions. Further, as the separator, for example, a microporous sheet made of resin or a non-woven fabric can be used.

The electrode body 600 is formed by arranging and winding a separator between the positive electrode plate and the negative electrode plate. Specifically, in the electrode body 600, the positive electrode plate and the negative electrode plate are wound so as to be displaced from each other in the direction of the winding axis (virtual axis parallel to the X-axis direction in the present embodiment) via the separator. ing. Then, in the positive electrode plate and the negative electrode plate, a portion where the active material is not applied (the active material layer is not formed) and the base material layer is exposed (active material layer non-formed portion) at the end portions in the shifted directions. )have. That is, the electrode body 600 has a positive electrode focusing portion in which the active material layer non-forming portion of the positive electrode plate is laminated and bundled at one end portion 610, and the active material layer of the negative electrode plate is provided at the other end portion 610. It has a negative electrode focusing portion in which non-forming portions are laminated and bundled. In the present embodiment, an elliptical shape is shown as the cross-sectional shape of the electrode body 600, but the cross-sectional shape of the electrode body 600 may be a circular shape, an elliptical shape, or the like.

The electrode terminal 200 is a terminal (positive electrode terminal and negative electrode terminal) electrically connected to the positive electrode plate and the negative electrode plate of the electrode body 600 via the current collector 500. That is, the electrode terminal 200 leads the electricity stored in the electrode body 600 to the external space of the power storage element 10, and also introduces electricity into the internal space of the power storage element 10 in order to store electricity in the electrode body 600. It is a metal member of. Further, the electrode terminal 200 is attached to a lid 120 arranged above the electrode body 600. Specifically, as shown in FIG. 2, in the electrode terminal 200, the shaft portion 210 collects the through hole 300a of the upper gasket 300, the through hole 120a of the lid body 120, and the through hole 410a of the lower gasket 400. By being inserted into the through hole 510a of the electric body 500 and crimped, it is fixed to the lid 120 together with the current collector 500. The electrode terminal 200 is made of aluminum, an aluminum alloy, copper, a copper alloy, or the like.

The current collector 500 is a member (positive electrode current collector and negative electrode current collector) arranged on both sides of the electrode body 600 in the X-axis direction and connected to the end portion 610 of the electrode body 600. Specifically, the current collector 500 is arranged between the end portion 610 of the electrode body 600 and the side wall of the container body 110, and the positive electrode focusing portion and the negative electrode focusing portion and the electrode terminal 200 of the end portion 610 of the electrode body 600 are arranged. It is a member having conductivity and rigidity which is electrically connected to and. Further, the current collector 500 is fixedly connected (bonded) to the lid body 120 and the end portion 610 of the electrode body 600, and with this configuration, the electrode body 600 is connected to the lid body 120 by the current collector 500. It is held (supported) in a suspended state, and shaking due to vibration or impact is suppressed. The material of the current collector 500 is not limited, but for example, the current collector 500 on the positive electrode side is formed of aluminum or an aluminum alloy, like the positive electrode base material layer of the electrode body 600, and is a current collector on the negative electrode side. The 500 is made of copper, a copper alloy, or the like, like the negative electrode base material layer of the electrode body 600.

The current collector 500 has a terminal connection portion 510 and two electrode body connection portions 520 arranged side by side in the Y-axis direction on the negative side in the Z-axis direction of the terminal connection portion 510. The terminal connection portion 510 is a base of the current collector 500 arranged on the electrode terminal 200 side (upper side, positive side in the Z-axis direction) of the current collector 500. The terminal connection portion 510 includes the above-mentioned through hole 510a.

The electrode body connecting portion 520 is a leg portion of the current collector 500 arranged on the electrode body 600 side (lower side, negative side in the Z-axis direction) of the current collector 500. Specifically, the electrode body connecting portion 520 has a long and flat plate shape extending from one end of the terminal connecting portion 510 in the X-axis direction and both ends in the Y-axis direction toward the minus side in the Z-axis direction. Is electrically and mechanically connected (bonded) to the end portion 610 of the electrode body 600.

The upper gasket 300 is arranged between the lid 120 of the container 100 and the electrode terminal 200, and is a member (positive electrode upper gasket and negative electrode upper gasket) that insulates and seals between the lid 120 and the electrode terminal 200. Is. Specifically, the upper gasket 300 has a shape in which a through hole 300a into which the shaft portion 210 of the electrode terminal 200 is inserted is formed in the central portion of the rectangular substantially plate-shaped member, and the through hole 300a is formed. The upper gasket 300 is fixed to the lid 120 by inserting and caulking the shaft portion 210. The upper gasket 300 is, for example, polypropylene (PP), polyethylene (PE), or polyphenylene sulfide resin (PPS), polyetheretherketone (PEEK), tetrafluoroethylene / perfluoroalkyl vinyl ether (PFA), polytetrafluoroethylene. It is formed of a resin such as (PTFE), polybutylene terephthalate (PBT), poly ether sulfone (PES) and the like.

The lower gasket 400 is a member (positive positive lower gasket and negative negative lower gasket) that is arranged between the lid 120 of the container 100 and the current collector 500 and insulates between the lid 120 and the current collector 500. Specifically, the lower gasket 400 has a shape in which a through hole 410a into which the shaft portion 210 of the electrode terminal 200 is inserted is formed in a substantially central portion of a rectangular substantially plate-shaped member. The lower gasket 400 is fixed to the lid 120 by inserting and crimping the shaft portion 210 into the 410a. The lower gasket 400 is formed of, for example, a resin such as PP, PE, PPS, PEEK, PFA, PTFE, PBT, PES and the like. A detailed description of the configuration of the lower gasket 400 will be described later.

[2 Detailed description of the configuration of the lower gasket 400]
Next, the configuration of the lower gasket 400 will be described in detail. FIG. 3 is a perspective view showing the configuration of the lower gasket 400 according to the present embodiment. Further, FIG. 4 is a cross-sectional view showing a configuration in which the lower gasket 400, the upper gasket 300, the current collector 500 and the electrode terminal 200 according to the present embodiment are attached to the lid body 120. FIG. 5 is a bottom view showing a configuration in which the lower gasket 400, the upper gasket 300, the current collector 500, and the electrode terminal 200 according to the present embodiment are attached to the lid 120. FIG. 4 is a cross-sectional view of the cut surface including the IV-IV line in FIGS. 3 and 5. Here, the lower gasket 400 on the negative electrode side will be described as an example, but the same applies to the positive electrode side.

As shown in FIGS. 3 to 5, the lower gasket 400 has a first gasket portion 410 and a second gasket portion 420. The first gasket portion 410 is arranged on the outside (plus side in the X-axis direction) of the lower gasket 400, and is a rectangular and flat plate-shaped portion parallel to the XY plane in which the above-mentioned circular through hole 410a is formed. Further, the first gasket portion 410 has a flat rectangular flat portion 411 on the lower surface (the surface on the minus side in the Z-axis direction). The flat surface portion 411 is arranged to face the terminal connection portion 510 of the current collector 500 and abuts on the upper surface of the terminal connection portion 510. Further, on the outer surface 415 of the first gasket portion 410, a stepped portion 413 recessed inward of the first gasket portion 410 is formed. The step portion 413 is continuously formed along the edge of the upper end portion (end portion on the plus side in the Z-axis direction) of the first gasket portion 410. That is, the step portion 413 is provided at the end portion on the outer surface 415 of the lower gasket 400 on the lid body 120 side. Specifically, the step portion 413 extends along the X-axis direction of the first gasket portion 410, and extends along the Y-axis direction of the first gasket portion 410 with a pair of edges facing each other in the Y-axis direction. It is provided continuously with the edge on the plus side in the X-axis direction. As shown in FIG. 5, in a state where the lower gasket 400, the upper gasket 300, the current collector 500, and the electrode terminal 200 are attached to the lid body 120, the step portion 413 corresponds to the case where the lid body 120 is viewed in a plan view. It is provided at a position facing each other along the side of the lid 120. That is, the step portion 413 is continuously provided with respect to the plurality of sides of the lid body 120.

In the present embodiment, the step portion 413 is illustrated in the case where the step portion 413 is not provided on the edge on the minus side in the X-axis direction of the first gasket portion 410, but the step portion 413 is provided on the edge. You may.

Further, as shown in FIG. 4, in the first gasket portion 410, each of the pair of outer surfaces 415 facing each other in the Y-axis direction is the outer surface 521 of the pair of electrode body connecting portions 520 of the current collector 500. It is located outward with a width of H1 or more.

Further, as shown in FIGS. 3 and 4, the upper surface (the surface on the plus side in the Z-axis direction) of the first gasket portion 410 is a recess that is continuous along the entire circumference of the through hole 410a, for example, an annular recess in a plan view. 412 is formed. As shown in FIG. 4, a part of the lid body 120 is housed in the recess 412. Specifically, on the lower surface of the lid 120 (the surface that abuts on the lower gasket 400), for example, a convex portion 121 that is continuous along the entire circumference of the through hole 120a and is annular in a plan view is formed. The convex portion 121 is accommodated in a state of being fitted to the concave portion 412 of the lower gasket 400. The upper surface of the lid 120 (the surface that abuts on the upper gasket 300) is provided with a recess 122 at a position corresponding to the convex portion 121. The recess 122 is formed, for example, in an annular shape in a plan view, which is continuous along the entire circumference of the through hole 120a.

A part of the upper gasket 300 is housed in the recess 122 of the lid 120. Specifically, on the lower surface of the upper gasket 300 (the surface that abuts on the lid 120), for example, a convex portion 301 that is continuous along the entire circumference of the through hole 300a and is annular in a plan view is formed. The convex portion 301 is accommodated in a state of being fitted to the concave portion 122 of the lid body 120. The upper surface of the upper gasket 300 (the surface that abuts on the electrode terminal 200) is provided with a recess 302 at a position corresponding to the convex portion 301. The recess 302 is formed, for example, in an annular shape in a plan view, which is continuous along the entire circumference of the through hole 300a.

Further, on the peripheral edge of the through hole 300a of the upper gasket 300, a cylindrical portion 305 protruding downward from the convex portion 301 is formed. The cylindrical portion 305 penetrates the through hole 120a of the lid 120 and the through hole 410a of the lower gasket 400. The tip of the cylindrical portion 305 is in contact with the upper surface of the terminal connection portion 510 of the current collector 500. In this state, the through hole 300a of the cylindrical portion 305 and the through hole 510a of the current collector 500 communicate with each other coaxially.

A part of the electrode terminal 200 is housed in the recess 302 of the upper gasket 300. Specifically, on the lower surface of the electrode terminal 200 (the surface that abuts on the upper gasket 300), for example, a convex portion 211 that is continuous along the entire circumference of the shaft portion 210 and is annular in a plan view is formed. The convex portion 211 is housed in a state of being fitted to the concave portion 302 of the upper gasket 300. The shaft portion 210 of the electrode terminal 200 is crimped to the tip portion 212 of the shaft portion 210 in a state of penetrating the through hole 300a of the upper gasket 300 and the through hole 510a of the current collector 500.

As shown in FIG. 4, when the lower gasket 400, the upper gasket 300, the current collector 500, and the electrode terminal 200 are attached to the lid 120, the step portion 413 is inside the outer surface 521 of the current collector 500. It is dented toward you. For example, assuming that there is no step portion 413, the creepage distance between the lid body 120 and the current collector 500 is the length L1. However, if the lower gasket 400 is provided with the step portion 413, the width H2 of the bottom surface of the step portion 413 is added to the length L1, so that the creepage distance can be extended. Further, in the present embodiment, the outer surface 415 of the first gasket portion 410 is located outside the outer surface 521 of the electrode body connecting portion 520 of the current collector 500 by a width H1 or more. Since this width H1 also joins the length L1 and the width H2, the creepage distance can be further extended.

[3 Explanation of effect]
As described above, according to the power storage element 10 according to the embodiment of the present invention, the electrode terminal 200 provided on the lid 120 of the container 100 and the current collector 500 electrically connected to the electrode terminal 200. A lower gasket 400 (insulating member) arranged so as to be accommodated between the lid 120 and the current collector 500 in the alignment direction is provided, and the outer surface 415 of the lower gasket 400 has a stepped portion 413 recessed inward. Is provided.

According to this, since the step portion 413 is formed on the outer surface 415 of the lower gasket 400, the creepage distance between the lid body 120 and the current collector 500 can be extended by the step portion 413. As a result, it is possible to suppress the occurrence of creeping discharge and tracking phenomenon.

Further, assuming that there is no step portion 413, if the entire outer surface 415 of the lower gasket 400 gets wet with the electrolytic solution, the lid body 120 and the current collector 500 are electrically connected by the electrolytic solution, resulting in a minute discharge. A liquid entanglement will occur. However, if the step portion 413 is provided on the outer surface 415 of the lower gasket 400, the creepage distance is extended, so that conduction between the lid 120 and the current collector 500 by the electrolytic solution is less likely to occur. Further, since the electrolytic solution is captured by the step portion 413, the electrolytic solution is less likely to drip to the current collector 500. From these facts, it is possible to suppress minute discharges and liquid entanglements caused by the electrolytic solution. Therefore, the electrical stability of the power storage element 10 can be improved.

Here, even if the step portion 413 is not provided, the creepage distance can be extended by forming the lower gasket 400 in a large size and projecting it to the outside of the current collector 500. However, the lower gasket 400 is preferably small in size because the inside of the container 100 is becoming denser in order to increase the capacity of the power storage element 10. As described above, if the step portion 413 is provided on the outer surface 415 of the lower gasket 400, the creepage distance can be extended even if the amount of the lower gasket 400 protruding from the outer surface 521 of the current collector 500 is small. can. That is, even in the power storage element 10 in which the inside of the container 100 has been made denser, the electrical stability can be improved.

Further, the step portion 413 is recessed inward from the outer surface 521 of the current collector 500.

According to this, since the step portion 413 is recessed inward from the outer surface 521 of the current collector 500, the creepage distance can be made longer, and the occurrence of creepage discharge and tracking phenomenon can be more reliably suppressed. be able to.

Further, the outer surface 415 of the lower gasket 400 is located outside the outer surface 521 of the current collector 500.

According to this, since the outer surface 415 of the lower gasket 400 is located outside the outer surface 521 of the current collector 500, the creepage distance can be extended. Further, since the outer surface 415 of the lower gasket 400 protrudes from the outer surface 521 of the current collector 500, the electrolytic solution adhering to the outer surface 415 of the lower gasket 400 is the outer surface 521 of the current collector 500. It becomes difficult to get wet and spread. Therefore, it is possible to further suppress minute discharges and liquid entanglements caused by the electrolytic solution, and it is possible to improve the electrical stability of the power storage element 10.

Further, the step portion 413 is provided at a position facing the lid 120 along the side of the lid 120 when the lid 120 of the container 100 is viewed in a plan view.

Here, in the lower gasket 400, when the lid 120 is viewed in a plan view, the portion that does not face the side of the lid 120 may be formed large and the creepage distance may be extended because the restriction by the container 100 is small. It is possible. On the other hand, in the lower gasket 400, when the lid 120 is viewed in a plan view, the portion facing the side of the lid 120 is largely restricted by the container 100, and it is difficult to form the lower gasket 400 in a large size. Therefore, if the step portion 413 is provided at a position facing the lid 120 along the side of the lid 120 when the lid 120 is viewed in a plan view, the creeping distance is provided by the step portion 413 even in a place where the restriction is large. Can be extended. Therefore, the electrical stability of the power storage element 10 can be improved.

Further, the step portion 413 is continuously provided with respect to a plurality of sides of the lid body 120 of the container 100.

According to this, since the lower gasket 400 is provided with the step portion 413 at a position continuous with respect to the plurality of sides of the lid body 120, the creepage distance at the place where the restriction is large can be extended as a whole. Therefore, the electrical stability of the power storage element 10 can be improved.

Further, the step portion 413 is provided at the end portion on the outer surface 415 of the lower gasket 400 on the lid body 120 side.

Here, when assembling the lid 120, the lower gasket 400, and the current collector 500 to the electrode terminal 200, the lid 120, with respect to the shaft 210, with the shaft 210 of the electrode terminal 200 facing upward. The lower gasket 400 and the current collector 500 may be attached in this order. For example, a feeder device is used at the time of assembly, but the lower gasket 400 has a flat surface facing upward in contact with the current collector 500, and the flat surface is attracted by the feeder. Therefore, the wider the flat surface of the lower gasket 400 that abuts on the current collector 500, the more stable adsorption is possible, which is preferable. For example, if the step portion 413 is provided at the end portion of the outer surface 415 of the lower gasket 400 on the current collector 500 side, the flat surface becomes narrow. On the other hand, as described above, if the step portion 413 is provided at the end portion of the outer surface 415 of the lower gasket 400 on the lid 120 side, the width of the flat surface can be increased. That is, the feeder device makes it possible to stably adsorb the lower gasket 400, and by extension, the accuracy of the assembly itself can be improved. If the lower gasket 400 and other members can be assembled accurately, it is possible to suppress the formation of a gap between them, and it is possible to improve the insulating property and the airtightness. That is, the electrical stability of the power storage element 10 can be improved.

[Explanation of Modifications of 4 Embodiments]
Next, a modified example of the above embodiment will be described. FIG. 6 is a perspective view showing the configuration of the lower gasket 400B according to the modified example of the present embodiment. Specifically, FIG. 6 is a diagram corresponding to FIG. 4. In the following description, the same parts as those in the above embodiment may be designated by the same reference numerals and the description thereof may be omitted.

As shown in FIG. 6, a stepped portion 413b recessed inward of the first gasket portion 410b is formed on the outer surface 415 of the first gasket portion 410b of the lower gasket 400B according to the modified example. The step portion 413b is continuously formed along the edge of the lower end portion (end portion on the minus side in the Z-axis direction) of the first gasket portion 410. That is, the step portion 413b is provided at the end portion on the outer surface 415b of the lower gasket 400B on the current collector 500 side. Further, the step portion 413b is located outside the recess 412 of the lower gasket 400B.

As described above, according to the power storage element according to the present modification, the same effect as that of the above embodiment can be obtained. In particular, in this modification, the step portion 413b is provided at the end of the outer surface 415b of the lower gasket 400B on the current collector 500 side, and is located outside the recess 412. Therefore, the lower gasket 400B can be formed to have a uniform wall thickness by the stepped portion 413b and the recessed portion 412. If the wall thickness of the lower gasket 400B is uniform, the lower gasket 400B can be easily molded, and the lower gasket 400B with high dimensional accuracy can be realized. If the dimensional accuracy of the lower gasket 400B is high, it is possible to improve the electrical stability of the power storage element.

(Other variants)
Although the power storage element according to the embodiment of the present invention and the modified example thereof has been described above, the present invention is not limited to the embodiment and the modified example thereof. That is, it should be considered that the embodiments disclosed this time and examples thereof are exemplary in all respects and are not restrictive. The scope of the present invention is shown by the scope of claims rather than the above description, and is intended to include all modifications within the meaning and scope equivalent to the scope of claims.

For example, in the above-described embodiment and its modification, the case where the stepped portion 413, 413b is provided at one end of the outer surface 415, 415b of the lower gaskets 400 and 400B is exemplified. However, the position of the step portion may be arbitrary as long as it is provided on the outer surface of the lower gasket. For example, a step portion may be provided at the center of the outer surface of the lower gasket.

Further, in the above embodiment, the stepped portion 413 recessed inward from the outer surface 521 of the current collector 500 is exemplified. However, the step portion does not have to reach the outer surface of the current collector.

Further, in the above embodiment, the case where the outer surface 415 of the lower gasket 400 is located outside the outer surface 521 of the current collector 500 is illustrated. However, the outer surface of the lower gasket may be flush with the outer surface of the current collector, or may be located inward of the outer surface of the current collector.

Further, in the above embodiment, the case where the step portion 413 is continuously provided on the plurality of sides of the lid 120 is illustrated, but the step portion is intermittent with respect to the plurality of sides of the lid 120. It may be provided in.

Further, in the above-described embodiment and its modification, the electrode body 600 is a so-called vertically wound winding type electrode body in which the winding axis is parallel to the lid body 120. However, the electrode body 600 may be a so-called horizontal winding type electrode body in which the winding axis is perpendicular to the lid body 120. Further, the shape of the electrode body 600 is not limited to the winding type, but a stack type in which flat plate-shaped electrode plates are laminated, or a shape in which the electrode plate and / or the separator is folded in a bellows shape (a rectangular electrode plate is formed by folding the separator in a zigzag shape). It may be sandwiched, or the electrode plate and the separator may be overlapped and then folded in a zigzag manner).

Further, in the above-described embodiment and its modification, both the positive electrode side and the negative electrode side have the above configuration, but only one of the positive electrode side and the negative electrode side has the above configuration. It may be absent.

Further, a form constructed by arbitrarily combining the components included in the above-described embodiment and its modifications is also included in the scope of the present invention.

Further, the present invention can be realized not only as such a power storage element but also as a lower gasket 400 (or 401) included in the power storage element.

The present invention can be applied to a power storage element such as a lithium ion secondary battery.

10 Power storage element 100 Container 110 Container body 120 Lid 120a, 300a, 410a, 510a Through holes 121, 211, 301 Convex 122, 302, 412 Concave 125 Gas discharge valve 200 Electrode terminal 210 Shaft 212 Tip 300 Upper gasket 305 Cylindrical part 400, 400B Lower gasket part 410, 410b First gasket part 411 Flat part 413, 413b Step part 415, 415b, 521 Outer side surface 420 Second gasket part 500 Current collector 510 Terminal connection part 520 Electrode body connection part 600 Electrode body 610 Ends H1, H2 Width L1 Length

Claims (8)

The electrode terminals provided on the container and
A current collector electrically connected to the electrode terminal and
It is provided with an insulating member arranged so as to be accommodated between the container and the current collector in the arrangement direction.
The outer surface of the insulating member is provided with an inwardly recessed step portion .
The step portion has facing surfaces facing the container or the current collector so as not to come into contact with the container, and is provided with respect to a plurality of sides of the container.
Power storage element. The power storage element according to claim 1, wherein the step portion is recessed inward from the outer surface of the current collector. The power storage element according to claim 1 or 2, wherein the outer surface of the insulating member is located outside the outer surface of the current collector. The power storage element according to any one of claims 1 to 3, wherein the step portion is provided at a position facing the container along the side of the container when the container is viewed in a plan view. The power storage element according to claim 4, wherein the step portion is continuously provided for a plurality of the sides of the container. The power storage element according to any one of claims 1 to 5, wherein the step portion is provided at an end portion on the outer surface of the insulating member on the container side. A recess in which the container fits is formed on the contact surface of the insulating member with which the container abuts.
The power storage element according to any one of claims 1 to 5, wherein the step portion is provided at an end portion on the outer surface of the insulating member on the current collector side and is located outside the recess. .. The electrode terminals provided on the container and
A current collector electrically connected to the electrode terminal and
It is provided with an insulating member arranged so as to be accommodated between the container and the current collector in the arrangement direction.
The outer surface of the insulating member is provided with an inwardly recessed step portion.
The step portion has facing surfaces facing each other so as not to come into contact with the container or the current collector, and is continuously provided from one end to the other end of the side of the insulating member facing along the side of the container. ing
Power storage element.

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