JP6984408B2 - Manufacturing method of power storage element and power storage element - Google Patents

Description

The present invention relates to a method for manufacturing a power storage element including an electrode body and a current collector, and a power storage element.

Conventionally, in a power storage element including an electrode body and a current collector, a configuration in which the current collector is connected to the electrode body by welding is widely known. For example, Patent Document 1 discloses a power storage element (non-aqueous electrolyte secondary battery) in which a current collector is connected to an electrode body (wound electrode body) by ultrasonic welding.

Japanese Unexamined Patent Publication No. 2017-10945

However, the conventional power storage element has a problem that a short circuit may occur due to the connection work between the electrode body and the current collector. That is, in the above-mentioned conventional power storage element, since the current collector is connected to the electrode body by ultrasonic welding, metal powder is generated during ultrasonic welding and the metal powder invades the inside of the electrode body. , May cause a short circuit. Therefore, it is conceivable to connect the current collector to the electrode body by resistance welding. However, when resistance welding is performed, for example, the separator inside the electrode shrinks due to the heat from the welded portion, and the positive electrode plate and the negative electrode plate come into contact with each other. This may also cause a short circuit.

The present invention has been made in view of the above problems, and provides a method for manufacturing a power storage element capable of suppressing the occurrence of a short circuit due to a connection operation between an electrode body and a current collector, and a power storage element. The purpose is.

In order to achieve the above object, the method for manufacturing a power storage element according to one aspect of the present invention is a current collector having an electrode body and an electrode body connecting portion connected to an end portion on the first direction side of the electrode body. It is a method of manufacturing a power storage element provided with A resistance welding step of forming a resistance welding portion on the inclined portion is included, and in the resistance welding step, the center position of the resistance welding portion is such that the electrode body connecting portion and the end portion of the electrode body face each other. The resistance welded portion is formed so as to be arranged on the first direction side of the center position of the portion.

According to this, in the method of manufacturing a power storage element, the inclined portion of the electrode body connecting portion of the current collector arranged on the first direction side of the electrode body and the end portion of the electrode body are resistance welded to form a resistance welded portion. At the time of formation, the center position of the resistance welded portion is arranged on the first direction side from the center position of the portion where the electrode body connecting portion and the end portion of the electrode body face each other. Here, the inclined portion is a portion of the electrode body connecting portion of the current collector that is inclined with respect to the first direction. Therefore, within the same length range in the first direction, it is possible to increase the length by inclining the inclined portion rather than arranging it along the first direction, whereby the inclined portion faces the inclined portion. The length of the end portion of the electrode body can also be increased. Further, the center position of the resistance welded portion is arranged on the first direction side from the center position of the facing portion between the electrode body connecting portion and the end portion of the electrode body so that the resistance welded portion is kept away from the electrode body. Form. In this way, the resistance welded portion is arranged away from the separator of the electrode body while increasing the length of the end portion of the electrode body. As a result, the distance between the resistance welded portion and the separator can be lengthened, so that it is possible to prevent the separator from shrinking due to the heat from the resistance welded portion and causing the positive electrode plate and the negative electrode plate to come into contact with each other. Therefore, it is possible to suppress the occurrence of a short circuit caused by the connection work between the electrode body and the current collector.

Further, the power storage element according to one aspect of the present invention includes an electrode body and a current collector arranged on the first direction side of the electrode body, and the current collector is connected to an end portion of the electrode body. It has an electrode body connecting portion to be formed, and the electrode body connecting portion is arranged so as to be inclined with respect to the first direction, and has an inclined portion in which a resistance welded portion with an end portion of the electrode body is formed. The center position of the resistance welded portion is arranged on the first direction side of the center position of the portion where the electrode body connecting portion and the end portion of the electrode body face each other.

According to this, in the power storage element, the electrode body connection portion of the current collector arranged on the first direction side of the electrode body is inclined with respect to the first direction, and the resistance welded portion with the end portion of the electrode body is formed. It has a formed inclined portion, and the center position of the resistance welded portion is arranged on the first direction side with respect to the center position of the portion where the electrode body connecting portion and the end portion of the electrode body face each other. As a result, within the same length range in the first direction, the length can be made longer by inclining the inclined portion than by arranging the inclined portion along the first direction. Therefore, the electrode body facing the inclined portion can be made longer. The length of the end of the can also be increased. Further, the center position of the resistance welded portion is arranged on the first direction side from the center position of the facing portion between the electrode body connecting portion and the end portion of the electrode body so that the resistance welded portion is kept away from the electrode body. Form. In this way, the resistance welded portion is arranged away from the separator of the electrode body while increasing the length of the end portion of the electrode body. As a result, the distance between the resistance welded portion and the separator can be lengthened, so that it is possible to prevent the separator from shrinking due to the heat from the resistance welded portion and causing the positive electrode plate and the negative electrode plate to come into contact with each other. Therefore, it is possible to suppress the occurrence of a short circuit caused by the connection work between the electrode body and the current collector.

Further, the electrode body connecting portion is further extended on the second direction side of the inclined portion opposite to the first direction in a direction different from the inclined direction of the inclined portion, and the electrode body is provided. It may have a first extension located along the end.

According to this, in the current collector, the electrode body connecting portion is extended on the second direction side opposite to the first direction of the inclined portion in a direction different from the inclined direction of the inclined portion, and the end of the electrode body is extended. It has a first extension along the section. In this way, since the first extension portion is extended in a direction different from the inclination direction of the inclined portion, the electrode body connecting portion has a curved shape. Therefore, the length of the electrode body connecting portion can be made longer and the length of the end portion of the electrode body can be made longer than that of forming the electrode body connecting portion in a straight line. As a result, the distance between the resistance welded portion and the separator can be lengthened, so that it is possible to prevent the separator from shrinking due to the heat from the resistance welded portion and causing the positive electrode plate and the negative electrode plate to come into contact with each other. Therefore, it is possible to suppress the occurrence of a short circuit caused by the connection work between the electrode body and the current collector.

Further, the length of the inclined portion in the inclined direction may be longer than the length of the first extended portion in the extended direction.

According to this, in the current collector, the length of the inclined portion of the electrode body connecting portion in the inclined direction is longer than the length of the first extending portion in the extending direction. Here, since the present application has a configuration in which the separator can be suppressed from shrinking due to heat from the resistance welded portion, the area of the resistance welded portion can be increased. Therefore, the length of the inclined portion in the inclined direction can be increased to increase the area of the resistance welded portion, whereby the joint area between the electrode body connecting portion and the end portion of the electrode body can be increased. .. In this way, by increasing the joint area between the electrode body connection portion and the end portion of the electrode body, the resistance between the electrode body connection portion and the end portion of the electrode body is reduced, and the electrode body connection portion is connected to the electrode body. Can be firmly fixed to the end of the.

Further, the first extension portion may be extended along the first direction.

According to this, in the current collector, the first extension portion of the electrode body connection portion is extended along the first direction, so that the electrode body connection portion comes into contact with the electrode body from an oblique direction. It is possible to suppress damage to the electrode body. As a result, it is possible to prevent the electrode body from being damaged and the positive electrode plate and the negative electrode plate from coming into contact with each other, so that it is possible to suppress the occurrence of a short circuit due to the connection work between the electrode body and the current collector. can.

Further, the electrode body connecting portion is further extended toward the second direction side of the first extending portion in a direction away from the end portion of the electrode body toward the second direction. It may have a part.

According to this, in the current collector, the electrode body connecting portion has a second extending portion on the second direction side of the first extending portion, which is separated from the end portion of the electrode body toward the second direction. There is. In this way, the second extension portion is extended in a direction away from the end portion of the electrode body, and the electrode body connection portion has a further curved shape, so that the electrode body connection portion comes into contact with the electrode body. This can further prevent damage to the electrode body. Further, the second extension portion acts as a cooling mechanism and can release heat generated during welding. As a result, it is possible to further suppress the damage of the electrode body and the contact between the positive electrode plate and the negative electrode plate, so that the occurrence of a short circuit due to the connection work between the electrode body and the current collector is further suppressed. be able to.

Further, the end portion of the electrode body has two focusing portions in which a plurality of electrode plates are laminated, and the current collector has two inclined portions corresponding to the two focusing portions. The two inclined portions may be arranged so as to be inclined from the first direction so as to be separated from each other toward the first direction.

According to this, the current collector has two inclined portions corresponding to the two focusing portions at the end of the electrode body, and the two inclined portions are separated from each other toward the first direction. Have been placed. By arranging the two inclined portions so as to be inclined apart from each other in this way, resistance welding between the inclined portion and the focusing portion can be easily performed. As a result, it is possible to avoid work that causes a short circuit during resistance welding, and it is possible to suppress the occurrence of a short circuit due to the work of connecting the electrode body and the current collector.

It should be noted that the present invention can be realized not only as such a method for manufacturing a power storage element and as a power storage element, but also as a method for manufacturing a current collector included in the power storage element and as the current collector. be able to.

According to the method for manufacturing a power storage element in the present invention, it is possible to suppress the occurrence of a short circuit caused by the connection work between the electrode body and the current collector.

It is a perspective view which shows the appearance of the power storage element which concerns on embodiment. It is a perspective view which shows the component arranged in the container 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 and sectional drawing which shows the structure of the positive electrode current collector which concerns on embodiment. It is sectional drawing which shows the structure in the state which the electrode body connection part of the positive electrode current collector which concerns on embodiment is connected to the end part of the electrode body. It is a perspective view which shows the structure of the positive electrode current collector which concerns on the modification 1 of embodiment. It is a perspective view which shows the structure of the positive electrode current collector which concerns on the modification 2 of embodiment. It is a perspective view which shows the structure of the positive electrode current collector which concerns on the modification 3 of embodiment.

Hereinafter, the power storage element and the manufacturing method thereof 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 of the power storage element, the arrangement direction of the pair of current collectors, the arrangement direction of both ends of the electrode body (the 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, or the arrangement direction of the legs (electrode body connecting portion) in one current collector is defined as the Y-axis direction. 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 to 3, 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 a perspective view showing components arranged inside the container 100 of the power storage element 10 according to the present embodiment. Specifically, FIG. 2 is a perspective view showing a configuration in a state where the container main body 111 is separated from the power storage element 10. Further, FIG. 3 is an exploded perspective view showing each component by disassembling the power storage element 10 according to the present embodiment. In FIG. 3, the container main body 111 is omitted.

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. 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, in the present embodiment, the rectangular parallelepiped (square) power storage element 10 is shown, but the shape of the power storage element 10 is not limited to the rectangular parallelepiped shape, and is other than a cylindrical shape, a long cylindrical shape, or a rectangular parallelepiped 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, a positive electrode terminal 200, and a negative electrode terminal 300. Further, as shown in FIG. 2, an electrode body 400, a positive electrode current collector 500, and a negative electrode current collector 600 are housed inside the container 100.

A gasket or the like is arranged 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 improve the insulating property and the airtightness. The figure is omitted. The same applies to the negative electrode side. Further, although an electrolytic solution (non-aqueous electrolyte) is sealed inside the container 100, 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. In addition to the above components, spacers arranged on the sides of the positive electrode current collector 500 and the negative electrode current collector 600, and a gas discharge valve for releasing the pressure in the container 100 when the pressure rises. Alternatively, an insulating film or the like that wraps the electrode body 400 or the like may be arranged.

The container 100 is composed of a container main body 111 having a rectangular tubular shape and a bottom, and a lid 110 which is a plate-shaped member that closes the opening of the container main body 111. Further, the container 100 can be sealed inside by accommodating the electrode body 400 or the like inside and then welding the lid 110 and the container body 111 or the like. The material of the lid 110 and the container body 111 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.

The electrode body 400 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 that can occlude and release 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 400 is formed by arranging and winding a separator between the positive electrode plate and the negative electrode plate. Specifically, in the electrode body 400, 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 400 has laminated electrode plates (positive electrode plate and negative electrode plate). The electrode body 400 has two focusing portions 411 and bundles in which the active material layer non-forming portion of the positive electrode plate is laminated and bundled on the end portion 410 on the X-axis positive direction side (hereinafter, also referred to as the first direction side). It has 412. Further, the electrode body 400 has two focusing portions (not shown) in which the active material layer non-forming portions of the negative electrode plate are laminated and bundled at the end portion 420 on the minus direction side of the X axis. For example, the thickness of the active material layer non-forming portion (current collector foil) of the positive electrode plate and the negative electrode plate is about 5 μm to 20 μm, and when these are bundled, for example, about 30 to 40 sheets, the thickness is substantially uniform. Two focusing portions are formed. In the present embodiment, an elliptical shape is shown as the cross-sectional shape of the electrode body 400, but a circular shape, an elliptical shape, or the like may be used.

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, the positive electrode terminal 200 and the negative electrode terminal 300 lead the electricity stored in the electrode body 400 to the external space of the power storage element 10, and the electricity is stored in the internal space of the power storage element 10 in order to store electricity in the electrode body 400. It is a metal electrode terminal for introducing. Further, the positive electrode terminal 200 and the negative electrode terminal 300 are attached to the lid 110 arranged above the electrode body 400. Specifically, as shown in FIG. 3, the positive electrode terminal 200 is crimped by inserting the protruding portion 210 into the through hole 110a of the lid 110 and the opening 511 of the positive electrode current collector 500. It is fixed to the lid 110 together with the positive electrode current collector 500. The same applies to the negative electrode terminal 300.

The positive electrode current collector 500 is a member that is arranged on the X-axis plus direction side (first direction side) of the electrode body 400 and is connected to the end portion 410 of the electrode body 400. Specifically, the positive electrode current collector 500 is arranged between the end portion 410 of the electrode body 400 and the side wall of the container body 111, and is electrically connected to the positive electrode terminal 200 and the positive electrode plate of the electrode body 400. It is a member having both conductivity and rigidity. Further, the negative electrode current collector 600 is a member arranged on the X-axis negative direction side of the electrode body 400 and connected to the end portion 420 of the electrode body 400. Specifically, the negative electrode collector 600 is arranged between the end portion 420 of the electrode body 400 and the side wall of the container body 111, and is electrically connected to the negative electrode terminal 300 and the negative electrode plate of the electrode body 400. It is a member having both conductivity and rigidity.

More specifically, the positive electrode current collector 500 and the negative electrode current collector 600 are conductive plates 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 shaped member. The positive electrode current collector 500 and the negative electrode current collector 600 are fixedly connected (bonded) to the lid 110. Further, the positive electrode current collector 500 and the negative electrode current collector 600 are fixedly connected (bonded) to the laminated electrode plates of the electrode body 400, that is, the end portions 410 and the end portions 420 of the electrode body 400, respectively. There is. With this configuration, the electrode body 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, impact, or the like is suppressed.

The material of the positive electrode current collector 500 is not limited, but is made of aluminum or an aluminum alloy, for example, like the positive electrode base material layer of the electrode body 400. Further, the material of the negative electrode current collector 600 is not limited, but is, for example, formed of copper or a copper alloy like the negative electrode base material layer of the electrode body 400.

[2 Detailed description of the configuration of the positive electrode current collector 500]
Here, as shown in FIG. 3, the positive electrode current collector 500 has a terminal connection portion 510 and electrode body connection portions 520 and 530. Hereinafter, these configurations will be described in detail with reference to FIGS. 4 and 5. FIG. 4 is a perspective view and a cross-sectional view showing the configuration of the positive electrode current collector 500 according to the present embodiment. Specifically, FIG. 4A is a perspective view showing the configuration of the positive electrode collector 500, and FIG. 4B is a configuration of the electrode body connecting portions 520 and 530 of the positive electrode collector 500. It is a cross-sectional view which shows (the cross-sectional view in the IVb-IVb cross section in (a) of FIG. 4). Further, FIG. 5 is a cross-sectional view showing a configuration in which the electrode body connecting portions 520 and 530 of the positive electrode current collector 500 according to the present embodiment are connected to the end portions 410 of the electrode body 400. Since the positive electrode current collector 500 and the negative electrode current collector 600 have the same configuration, the configuration of the positive electrode current collector 500 will be described below, and the configuration of the negative electrode current collector 600 will be described. Is omitted.

As shown in these figures, the positive electrode current collector 500 includes a terminal connection portion 510 and electrode body connection portions 520 and 530 arranged side by side in the Y-axis direction on the Z-axis minus direction side of the terminal connection portion 510. have. The terminal connection portion 510 is a base of the positive electrode current collector 500 arranged on the positive electrode terminal 200 side (upper side, Z-axis plus direction side) of the positive electrode current collector 500. Specifically, the terminal connection portion 510 is a flat plate-shaped portion parallel to the XY plane on which the above-mentioned circular opening 511 is formed, and is electrically and mechanically connected (bonded) to the positive electrode terminal 200. To.

The electrode body connecting portions 520 and 530 are legs of the positive electrode current collector 500 arranged on the electrode body 400 side (lower side, Z-axis minus direction side) of the positive electrode current collector 500. Specifically, the electrode body connecting portions 520 and 530 extend from the end portions of the terminal connecting portion 510 on the X-axis positive direction side and the Y-axis positive direction side and the Y-axis negative direction side toward the Z-axis negative direction side. It is a long and flat plate-shaped portion that is electrically and mechanically connected (bonded) to the electrode body 400.

That is, as shown in FIG. 5, the electrode body connecting portions 520 and 530 are connected to the end portions 410 on the X-axis plus direction side (first direction side) of the electrode body 400. Specifically, the electrode body connecting portion 520 is arranged on the Y-axis plus direction side of the focusing portion 411 of the end portion 410 of the electrode body 400, and is joined to the focusing portion 411. Further, the electrode body connecting portion 530 is arranged on the Y-axis minus direction side of the focusing portion 412 of the end portion 410 of the electrode body 400, and is joined to the focusing portion 412. As a result, the focusing portion 411 becomes a portion where the electrode plates are laminated in the normal direction of the contact surface with the electrode body connecting portion 520, and the focusing portion 412 becomes a portion in the normal direction of the contact surface with the electrode body connecting portion 530. It is the part where the electrode plates are laminated. A backing plate may be arranged so as to sandwich the focusing portion 411 with the electrode body connecting portion 520 on the Y-axis minus direction side of the focusing portion 411, or on the Y-axis plus direction side of the focusing portion 412. A backing plate may be arranged so as to sandwich the focusing portion 412 with the electrode body connecting portion 530.

[Detailed description of the configuration of 3 electrode body connection portions 520 and 530]
Here, the configurations of the electrode body connecting portions 520 and 530 will be described in detail. As shown in FIGS. 4 and 5, the electrode body connecting portion 520 has an inclined portion 521, a first extending portion 522, and a second extending portion 523. Further, the electrode body connecting portion 530 has an inclined portion 531, a first extending portion 532, and a second extending portion 533. Since the electrode body connecting portion 520 and the electrode body connecting portion 530 have symmetrical shapes in the Y-axis direction, the description of the configuration of the electrode body connecting portion 520 will be mainly described below. The description of the configuration of the connection portion 530 may be simplified or omitted.

The inclined portion 521 is a portion of the electrode body connecting portion 520 on the first direction side (X-axis plus direction side), and is arranged so as to be inclined with respect to the first direction. Specifically, the inclined portion 521 is a rectangular and flat plate-shaped portion extending in the Z-axis direction, which is arranged so as to be inclined toward the Y-axis plus direction toward the X-axis plus direction. For example, the inclined portion 521 is inclined at an angle of about 45 ° from the X-axis direction to the Y-axis plus direction side. Further, the inclined portion 531 is a rectangular and flat plate-shaped portion extending in the Z-axis direction arranged inclined with respect to the first direction, like the inclined portion 521, but unlike the inclined portion 521, the inclined portion 531 has an X. It is arranged so as to be inclined toward the minus direction of the Y axis toward the plus direction of the axis. For example, the inclined portion 531 is inclined at an angle of about 45 ° from the X-axis direction to the Y-axis minus direction side. As described above, the two inclined portions 521 and 531 are arranged so as to be inclined from the first direction so as to be separated from each other toward the first direction.

Further, the two inclined portions 521 and 531 are arranged corresponding to the two focusing portions 411 and 412. Specifically, the inclined portion 521 is arranged on the Y-axis plus direction side of the focusing portion 411 and is joined to the focusing portion 411 by resistance welding. As a result, a resistance welded portion 700 with the end portion 410 of the electrode body 400 is formed on the inclined portion 521. The resistance welded portion 700 is a welded portion formed by resistance welding the inclined portion 521 and the focusing portion 411, and in the present embodiment, the X-axis plus a little more than the center position of the inclined portion 521 in the X-axis direction. It is formed in a position closer to the direction. Further, the inclined portion 531 is arranged on the Y-axis minus direction side of the focusing portion 412, and is joined to the focusing portion 412 by resistance welding. As a result, the inclined portion 531 is formed with a resistance welded portion 700 with the end portion 410 of the electrode body 400, similarly to the inclined portion 521.

The position and shape of the resistance welded portion 700 in the Z-axis direction are not particularly limited, but for example, the inclined portions 521 and 531 are located at two locations on the Z-axis plus direction side and the Z-axis minus direction side, or at the center in the Z-axis direction. Circular or rectangular resistance welded portions 700 are formed at three locations including the positions.

The first extending portion 522 is extended on the second direction side (X-axis minus direction side) opposite to the first direction of the inclined portion 521 in a direction different from the inclined direction of the inclined portion 521, and is an electrode. It is a portion arranged along the end 410 of the body 400. That is, the first extension portion 522 is a portion extended along the first direction. Specifically, the first extension portion 522 extends in the X-axis minus direction along the focusing portion 411 from the end portion of the inclined portion 521 on the X-axis minus direction side, in the Z-axis direction. It is a rectangular and flat plate-shaped part that extends. With such a configuration, a bent portion 524 is formed between the inclined portion 521 and the first extending portion 522. The bent portion 524 is a portion where the electrode body connecting portion 520 is bent or curved, which is formed at the boundary portion between the inclined portion 521 and the first extending portion 522. In the present embodiment, the bent portion 524 has a shape in which a convex portion is formed on the negative direction side of the Y axis and a concave portion is formed on the positive direction side of the Y axis. Since the first extension section 532 has the same configuration as the first extension section 522, the description thereof will be omitted.

The second extension portion 523 extends toward the second direction side (X-axis minus direction side) of the first extension portion 522 in a direction away from the end portion 410 of the electrode body 400 toward the second direction. Is. Specifically, the second extension portion 523 extends from the end portion of the first extension portion 522 on the minus direction side of the X axis toward the minus direction of the X axis and the plus direction of the Y axis along the focusing portion 411. It is a rectangular and flat plate-shaped portion extending in the Z-axis direction. That is, the second extension portion 523 is arranged so as to be inclined toward the Y-axis plus direction toward the X-axis minus direction. With such a configuration, a bent portion 525 is formed between the first extending portion 522 and the second extending portion 523. The bent portion 525 is a portion formed at the boundary between the first extending portion 522 and the second extending portion 523, in which the electrode body connecting portion 520 is bent or curved. In the present embodiment, the bent portion 525 has a shape in which a convex portion is formed on the negative direction side of the Y axis and a concave portion is formed on the positive direction side of the Y axis. Since the second extension section 533 has the same configuration as the second extension section 523, the description thereof will be omitted.

Further, as shown in FIG. 4, the length of the inclined portion 521 in the inclined direction (length L1 in the figure) is based on the length of the first extended portion 522 in the extended direction (length L2 in the figure). Is also long. In the present embodiment, since the length of the first extension portion 522 in the extension direction and the length of the second extension portion 533 in the inclination direction are about the same length, the length of the inclination portion 521 in the inclination direction is the same. Is longer than the length of the second extension 533 in the inclined direction. Further, the length of the inclined portion 521 in the inclined direction is longer than the sum of the length of the first extending portion 522 in the extending direction and the length of the inclined portion 521 in the inclined direction. Also, regarding the length in the X-axis direction, the length of the inclined portion 521 is the length of the first extension portion 522, the length of the second extension portion 523, and the first extension portion 522 and the second. It is longer than any of the total lengths with the extension 523. The same applies to the electrode body connecting portion 530 side.

Further, as shown in FIG. 5, since the resistance welded portion 700 is formed on the inclined portion 521, it is provided on the first direction side (X-axis plus direction side) of the electrode body connecting portion 520. Specifically, the center position of the resistance welded portion 700 is arranged on the first direction side from the center position of the portion where the electrode body connecting portion 520 and the end portion 410 of the electrode body 400 face each other. That is, the center position of the resistance welded portion 700 (center position P in the figure) is the center position (center in the figure) of the portion facing the focusing portion 411 of the electrode body connecting portion 520 (the portion in the region R1 in the figure). It is arranged on the first direction side from the position Q1). In the present embodiment, the center position P of the resistance welded portion 700 is the center position (the center position Q2 in the figure) of the portion where the inclined portion 521 and the first extension portion 522 are combined (the portion in the region R2 in the figure). ) Is located on the first direction side. Further, the center position P of the resistance welded portion 700 is arranged on the first direction side with respect to the center position (center position Q3 in the figure) of the inclined portion 521 (the portion in the region R3 in the figure). The same applies to the electrode body connecting portion 530 side.

[4 Description of Manufacturing Method of Power Storage Element 10]
Next, a method for manufacturing the power storage element 10 having the above configuration will be described. Specifically, a resistance welding step of forming a resistance welded portion 700 by resistance welding the electrode body connecting portion 520 and the end portion 410 of the electrode body 400 will be described. The same applies to the electrode body connecting portion 530 side.

That is, in this resistance welding step, the inclined portion 521 of the electrode body connecting portion 520 inclined with respect to the first direction and the end portion 410 of the electrode body 400 are resistance welded to form the inclined portion. A resistance welded portion 700 is formed on 521. Specifically, the electrode body connecting portion 520 is arranged on the Y-axis plus direction side of the focusing portion 411 so that the inclined portion 521 is inclined with respect to the X-axis direction. Then, the resistance welded portion 700 is formed by resistance welding the inclined portion 521 and the focusing portion 411.

Further, in this resistance welding step, the center position of the resistance welded portion 700 is arranged on the first direction side from the center position of the portion where the electrode body connecting portion 520 and the end portion 410 of the electrode body 400 face each other. As described above, the resistance welded portion 700 is formed. That is, the center position (center position P) of the resistance welded portion 700 is on the first direction side of the center position (center position Q1) of the portion (the portion in the region R1) facing the focusing portion 411 of the electrode body connecting portion 520. The resistance welded portion 700 is formed so as to be arranged in.

[5 Explanation of effect]
As described above, according to the method for manufacturing the power storage element 10 according to the embodiment of the present invention, the inclined portion 521 of the electrode body connecting portion 520 of the positive electrode current collector 500 and the end portion 410 of the electrode body 400 are resistance welded. When forming the resistance welded portion 700, the center position of the resistance welded portion 700 is on the first direction side from the center position of the portion where the electrode body connecting portion 520 and the end portion 410 of the electrode body 400 face each other. Place in. Here, the inclined portion 521 is a portion of the electrode body connecting portion 520 of the positive electrode current collector 500 that is inclined with respect to the first direction. Therefore, within the range of the same length in the first direction, the length can be made longer by inclining the inclined portion 521 than by arranging the inclined portion 521 along the first direction. The length of the end 410 of the opposing electrode body 400 can also be increased. Further, the center position of the resistance welded portion 700 is arranged on the first direction side from the center position of the facing portion between the electrode body connecting portion 520 and the end portion 410 of the electrode body 400, and the resistance welded portion 700 is placed on the electrode. It is formed so as to be away from the body 400. In this way, the resistance welded portion 700 is arranged away from the separator of the electrode body 400 while increasing the length of the end portion 410 of the electrode body 400. As a result, the distance between the resistance welded portion 700 and the separator can be lengthened, so that it is possible to prevent the separator from shrinking due to the heat from the resistance welded portion 700 and causing the positive electrode plate and the negative electrode plate to come into contact with each other. .. Therefore, it is possible to suppress the occurrence of a short circuit caused by the connection work between the electrode body 400 and the positive electrode current collector 500.

Further, according to the power storage element 10 according to the embodiment of the present invention, the electrode body connecting portion 520 of the positive electrode current collector 500 is inclined with respect to the first direction, and resistance welding with the end portion 410 of the electrode body 400 is performed. It has an inclined portion 521 in which the portion 700 is formed. The center position of the resistance welded portion 700 is arranged on the first direction side of the center position of the portion where the electrode body connecting portion 520 and the end portion 410 of the electrode body 400 face each other. As a result, as described above, the distance between the resistance welded portion 700 and the separator can be increased, so that the separator shrinks due to the heat from the resistance welded portion 700 and the positive electrode plate and the negative electrode plate are prevented from coming into contact with each other. can do. Therefore, it is possible to suppress the occurrence of a short circuit caused by the connection work between the electrode body 400 and the positive electrode current collector 500. Further, since the inclined portion 521 can be made longer than the inclined portion 521, the cross-sectional area of the positive electrode current collector 500 can be increased, and the resistance when a current flows through the positive electrode current collector 500 can be increased. Can be reduced.

Further, in the positive electrode current collector 500, the electrode body connecting portion 520 is on the second direction side (X-axis minus direction side) opposite to the first direction of the inclined portion 521, in a direction different from the inclined direction of the inclined portion 521. Has a first extension 522 along the end 410 of the electrode body 400. As described above, the first extending portion 522 is extended in a direction different from the inclined direction of the inclined portion 521, so that the electrode body connecting portion 520 has a curved shape. Therefore, the length of the electrode body connecting portion 520 can be made longer than that of forming the electrode body connecting portion 520 in a straight line, and the length of the end portion 410 of the electrode body 400 can also be made longer. As a result, the distance between the resistance welded portion 700 and the separator can be lengthened, so that it is possible to prevent the separator from shrinking due to the heat from the resistance welded portion 700 and causing the positive electrode plate and the negative electrode plate to come into contact with each other. .. Therefore, it is possible to suppress the occurrence of a short circuit caused by the connection work between the electrode body 400 and the positive electrode current collector 500.

Further, the bent shape of the electrode body connecting portion 520 can improve the strength of the electrode body connecting portion 520. Therefore, it is possible to prevent the electrode body 400 from being damaged due to damage to the electrode body connecting portion 520. As a result, it is possible to prevent the electrode body 400 from being damaged and the positive electrode plate and the negative electrode plate from coming into contact with each other, so that the occurrence of a short circuit can be suppressed. Further, since the electrode body connecting portion 520 has a curved shape, the cross-sectional area of the positive electrode current collector 500 can be increased, so that the resistance when a current flows through the positive electrode current collector 500 can be reduced.

Further, in the positive electrode current collector 500, the length of the inclined portion 521 of the electrode body connecting portion 520 in the inclined direction is longer than the length of the first extending portion 522 in the extending direction. Here, since the present application has a configuration in which the separator can be suppressed from shrinking due to the heat from the resistance welded portion 700, the area of the resistance welded portion 700 can be increased. Therefore, the length of the inclined portion 521 in the inclined direction can be increased to increase the area of the resistance welded portion 700, whereby the joint area between the electrode body connecting portion 520 and the end portion 410 of the electrode body 400 can be increased. Can be made larger. In this way, by increasing the joint area between the electrode body connecting portion 520 and the end portion 410 of the electrode body 400, the resistance between the electrode body connecting portion 520 and the end portion 410 of the electrode body 400 is reduced, and the electrode is formed. The body connection portion 520 can be firmly fixed to the end portion 410 of the electrode body 400.

Further, in the positive electrode current collector 500, the first extension portion 522 of the electrode body connection portion 520 is extended along the first direction, so that the electrode body connection portion 520 is attached to the electrode body 400 from an oblique direction. It is possible to prevent the electrode body 400 from being damaged by contact with the electrode body 400. As a result, it is possible to prevent the electrode body 400 from being damaged and the positive electrode plate and the negative electrode plate from coming into contact with each other. It can be suppressed.

Further, in the positive electrode current collector 500, the electrode body connecting portion 520 is located on the second extending side of the first extending portion 522, and the second extending portion 523 is separated from the end portion 410 of the electrode body 400 toward the second direction. have. In this way, the second extending portion 523 is extended in a direction away from the end portion 410 of the electrode body 400, and the electrode body connecting portion 520 has a further curved shape, so that the electrode body connecting portion 520 is formed. , It is possible to further suppress the contact with the electrode body 400 and damage to the electrode body 400. Further, the second extension portion 523 acts as a cooling mechanism and can release heat generated during welding. As a result, it is possible to further prevent the electrode body 400 from being damaged and the positive electrode plate and the negative electrode plate from coming into contact with each other, so that a short circuit occurs due to the connection work between the electrode body 400 and the positive electrode collector 500. Can be further suppressed.

Further, the strength of the electrode body connecting portion 520 can be further improved by further bending the electrode body connecting portion 520. Therefore, it is possible to further prevent the electrode body 400 from being damaged due to the damage of the electrode body connecting portion 520. As a result, it is possible to further suppress the damage of the electrode body 400 and the contact between the positive electrode plate and the negative electrode plate, so that the occurrence of a short circuit can be further suppressed. Further, since the electrode body connecting portion 520 has a further curved shape, the cross-sectional area of the positive electrode current collector 500 can be further increased, so that the resistance when a current flows through the positive electrode current collector 500 can be further reduced. Can be done.

Further, the positive electrode current collector 500 has two inclined portions 521 and 531 corresponding to two focusing portions 411 and 412 of the end portion 410 of the electrode body 400, and the two inclined portions 521 and 531 have the two inclined portions 521 and 531. They are arranged so that they are separated from each other toward the first direction. By arranging the two inclined portions 521 and 531 so as to be inclined apart from each other in this way, resistance welding between the inclined portions 521 and 531 and the focusing portions 411 and 412 can be easily performed. As a result, it is possible to avoid work that causes a short circuit during resistance welding, and it is possible to suppress the occurrence of a short circuit due to the work of connecting the electrode body 400 and the positive electrode current collector 500.

Since the electrode body connecting portion 530 side has the same configuration as the electrode body connecting portion 520 side, the same effect can be obtained.

[Explanation of 6 Modifications of the Embodiment]
(Modification 1)
Next, a modification 1 of the above embodiment will be described. FIG. 6 is a perspective view showing the configuration of the positive electrode current collector 500a according to the first modification of the present embodiment. It should be noted that the figure corresponds to FIG. 4 (a).

As shown in FIG. 6, the positive electrode current collector 500a in the present modification has electrode body connecting portions 520a and 530a instead of the electrode body connecting portions 520 and 530 of the positive electrode current collector 500 in the above embodiment. ing. The electrode body connecting portions 520a and 530a have inclined portions 521 and 531 and first extending portions 522 and 532 in the above embodiment, but do not have second extending portions 523 and 533. .. Other configurations of this modification are the same as those of the above embodiment, and detailed description thereof will be omitted.

As described above, according to the power storage element according to the present modification, the same effect as that of the above embodiment (excluding the effect related to the second extension portions 523 and 533) can be obtained. In particular, in this modification, since the second extension portions 523 and 533 in the above embodiment are not provided, the positive electrode current collector 500a can be easily manufactured. The same deformation can be applied to the electrode body connecting portion 530 side.

(Modification 2)
Next, a modification 2 of the above embodiment will be described. FIG. 7 is a perspective view showing the configuration of the positive electrode current collector 500b according to the second modification of the present embodiment. It should be noted that the figure corresponds to FIG. 4 (a).

As shown in FIG. 7, the positive electrode current collector 500b in this modification has electrode body connecting portions 520b and 530b instead of the electrode body connecting portions 520 and 530 of the positive electrode current collector 500 in the above embodiment. ing. The electrode body connecting portions 520b and 530b have inclined portions 521b and 531b corresponding to the inclined portions 521 and 531 in the above embodiment, but the first extending portions 522 and 532 and the second extending portions 523 and It does not have 533. Other configurations of this modification are the same as those of the above embodiment, and detailed description thereof will be omitted.

As described above, according to the power storage element according to the present modification, the same effects as those of the above embodiment (excluding the effects related to the first extension portions 522 and 532 and the second extension portions 523 and 533). Can play. In particular, in this modification, since the first extension portions 522 and 532 and the second extension portions 523 and 533 in the above embodiment are not provided, the positive electrode current collector 500b can be more easily manufactured. .. The same deformation can be applied to the electrode body connecting portion 530 side.

(Modification 3)
Next, a modification 3 of the above embodiment will be described. FIG. 8 is a perspective view showing the configuration of the positive electrode current collector 500c according to the third modification of the present embodiment. It should be noted that the figure corresponds to FIG. 4 (a).

As shown in FIG. 8, the positive electrode current collector 500c in this modification has electrode body connecting portions 520c and 530c instead of the electrode body connecting portions 520 and 530 of the positive electrode current collector 500 in the above embodiment. ing. The electrode body connecting portions 520c and 530c have inclined portions 521c and 531c corresponding to the inclined portions 521 and 531 in the above-described embodiment, as in the modified example 2, but the first extending portions 522 and 532 have the same. And the second extension parts 523 and 533 do not have. Other configurations of this modification are the same as those of the above embodiment, and detailed description thereof will be omitted.

In this modification, the inclined portions 521c and 531c have a shape twisted around the Z axis. That is, the end portions of the inclined portions 521c and 531c on the plus direction side of the Z axis are oriented in the first direction (plus direction of the X axis), but the inclined portions are gradually inclined with respect to the first direction toward the minus direction of the Z axis. It has a shape that goes on. Specifically, the inclined portions 521c and 531c have a shape that gradually inclines from the first direction so that the end portions on the plus direction side of the X axis gradually separate toward the minus direction of the Z axis. ing.

As described above, according to the power storage element according to the present modification, the same effect as that of the modification 2 can be obtained. In particular, in this modification, since the inclined portions 521c and 531c can be formed by twisting the electrode body connecting portions 520c and 530c, the positive electrode current collector 500c can be easily manufactured. The same deformation can be applied to the electrode body connecting portion 530 side.

(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 length of the inclined portion 521 in the inclined direction is longer than the length of the first extended portion 522 in the extended direction. However, the length of the inclined portion 521 in the inclined direction may be equal to or less than the length of the first extended portion 522 in the extended direction. Further, although the length of the inclined portion 521 in the inclined direction is longer than the length of the second extending portion 523 in the extending direction, it may be longer than the length.

Further, in the above-described embodiment and its modification, the first extension portion 522 is extended along the first direction. However, the first extension portion 522 may be extended so as to be inclined with respect to the first direction. For example, the first extension portion 522 may be inclined in the same direction as the inclination direction of the second extension portion 523 (a direction different from the inclination direction of the inclination portion 521). Further, the first extension portion 522 may be extended with an inclination angle smaller than that of the inclined portion 521 and inclined in the same direction as the inclination direction of the inclined portion 521.

Further, in the above-described embodiment and its modification, the electrode body 400 is a so-called vertically wound winding type electrode body in which the winding axis is parallel to the lid body 110. However, the electrode body 400 may be a so-called horizontal winding type electrode body in which the winding axis is perpendicular to the lid body 110. Further, the shape of the electrode body 400 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 embodiment and its modification, the positive electrode current collector 500 and the electrode body 400 are joined only by resistance welding, but in addition to resistance welding, other joining methods such as caulking joining are used. May be joined by. By performing joining by other joining methods, it is possible to improve the joining strength and reduce the contact resistance.

Further, in the above embodiment and its modification, it is assumed that both the electrode body connecting portions 520 and 530 of the positive electrode current collector 500 have the above configuration, but any of the electrode body connecting portions 520 and 530 It may be possible that only one of them has the above configuration.

Further, in the above-described embodiment and its modification, both the positive electrode current collector 500 and the negative electrode current collector 600 have the above-mentioned configurations, but the positive electrode current collector 500 and the negative electrode current collector 600 have the above-mentioned configurations. It may be possible that only one of the above configurations is provided.

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 method for manufacturing a power storage element and as a power storage element, but also as a method for manufacturing a current collector included in the power storage element and as the current collector. be able to.

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 Lid 110a Through hole 111 Container body 200 Positive electrode terminal 210 Protruding part 300 Negative electrode terminal 400 Electrode body 410, 420 End part 411, 412 Focusing part 500, 500a, 500b, 500c Positive electrode collector 510 Terminal connection Part 511 Opening part 520, 520a, 520b, 520c, 530 Electrode body connection part 521, 521b, 521c, 513 Inclined part 522, 532 First extension part 523, 533 Second extension part 524, 525 Bending part 600 Negative electrode collection Electrode 700 Resistance welded part

Claims (7)

A method for manufacturing a power storage element comprising an electrode body and a current collector having an electrode body connecting portion connected to an end portion on the first direction side of the electrode body.
Resistance welding to form a resistance welded portion on the inclined portion by resistance welding the inclined portion of the electrode body connecting portion inclined with respect to the first direction and the end portion of the electrode body. Including the process
In the resistance welding step, the center position of the resistance welded portion is arranged on the first direction side with respect to the center position of the portion where the electrode body connecting portion and the end portion of the electrode body face each other. , Forming the resistance welded portion,
Manufacturing method of power storage element. The electrode body and the current collector arranged on the first direction side of the electrode body are provided.
The current collector has an electrode body connecting portion connected to an end portion of the electrode body, and has an electrode body connecting portion.
The electrode body connecting portion is arranged so as to be inclined with respect to the first direction, and has an inclined portion in which a resistance welded portion with an end portion of the electrode body is formed.
The center position of the resistance welded portion is arranged on the first direction side of the center position of the portion where the electrode body connecting portion and the end portion of the electrode body face each other.
Power storage element. The electrode body connection portion further
A first extension extending in a direction different from the inclination direction of the inclined portion and arranged along an end portion of the electrode body on the second direction side of the inclined portion opposite to the first direction. Has a sill,
The power storage element according to claim 2. The length of the inclined portion in the inclined direction is longer than the length of the first extending portion in the extending direction.
The power storage element according to claim 3. The first extension portion is extended along the first direction.
The power storage element according to claim 3 or 4. The electrode body connection portion further
On the second direction side of the first extension portion, there is a second extension portion that extends in a direction away from the end portion of the electrode body toward the second direction.
The power storage element according to any one of claims 3 to 5. The end portion of the electrode body has two focusing portions in which a plurality of electrode plates are laminated.
The current collector has two inclined portions corresponding to the two focusing portions.
The two inclined portions are arranged so as to be inclined from the first direction so as to be separated from each other toward the first direction.
The power storage element according to any one of claims 2 to 6.

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