JP6937586B2 - Power storage element - Google Patents

Description

The present invention relates to a power storage element including an electrode body.

For a power storage element such as a lithium ion secondary battery, the positive electrode and the negative electrode are electrically insulated from each other, for example, as in the non-aqueous electrolyte secondary battery as the lithium ion secondary battery described in Patent Document 1. Some have an electrode body formed by being laminated via a separator having a property. The positive electrode of the electrode laminate as the electrode body described in Patent Document 1 has a positive electrode portion in which a positive electrode active material layer is formed on a positive electrode current collector as a base material, and a positive electrode tab. The positive electrode tab is formed integrally with the positive electrode current collector by connecting with a curved portion continuous with the peripheral edge of the positive electrode portion. The negative electrode has a negative electrode portion in which a negative electrode active material layer is formed on a negative electrode current collector which is a base material, and a negative electrode tab. The negative electrode tab is formed integrally with the negative electrode current collector by connecting with a curved portion continuous with the peripheral edge of the negative electrode portion. Further, the projected portion obtained by projecting the positive electrode portion perpendicularly to the negative electrode portion exists inside the outer shape of the negative electrode active material layer.

International Publication No. 2013/031891

In the electrode laminate described in Patent Document 1, the curved portion formed at the base end of the positive electrode tab is located on the peripheral edge of the positive electrode portion, and is a negative electrode in a direction perpendicular to the stacking direction of the positive electrode and the negative electrode. It is located inside the electrode laminate rather than the periphery of the portion. The curved portion formed at the base end of the negative electrode tab is located on the peripheral edge of the negative electrode electrode portion, and is located outside the electrode laminated body with respect to the peripheral edge of the negative electrode electrode portion in the direction perpendicular to the stacking direction. Therefore, the width of the negative electrode tab in the direction along the peripheral edge of the negative electrode portion is larger than the width of the positive electrode tab in the direction along the peripheral edge of the negative electrode portion outside the peripheral edge of the negative electrode electrode portion. Further, when the positive electrode and the negative electrode are laminated, the positive electrode tabs are lined up in a stacking direction to form a bundle, and the negative electrode tabs are lined up in a row in the stacking direction to form a bundle. Then, the positive electrode tab and the negative electrode tab of the bundle may be arranged in a direction along the peripheral edge of the negative electrode portion and deviated from the target position. Since the area occupied by the bundle of positive electrode tabs and the bundle of negative electrode tabs is usually limited in relation to other components, the accuracy of stacking negative electrode tabs having a larger width outside the peripheral edge of the negative electrode portion is allowed. The degree is narrow and the manufacturing cost rises.

The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide a power storage element that widens the tolerance of stacking accuracy of the negative electrode tab of the negative electrode plate as the negative electrode.

In order to achieve the above object, the power storage element according to one aspect of the present invention includes an electrode body including a laminated positive electrode plate and a negative electrode plate, and the positive electrode plate is formed from a linear first edge of the positive electrode plate. The negative electrode plate includes a positive electrode tab protruding in the first direction, the negative electrode plate includes a negative electrode tab protruding in the first direction from the linear second edge of the negative electrode plate, and the second edge is from the first edge. Also, the positive electrode tab is located so as to project in the first direction, the positive electrode tab has a first rounded portion having a radius at the base end, and the negative electrode tab has a base end from the first rounded portion. Also has a second rounded portion with a small radius of curvature radius.

The maximum width of the negative electrode tab in the second direction orthogonal to the first direction may be equal to or less than the maximum width in the second direction at the protruding portion of the positive electrode tab protruding from the second edge.

Further, the power storage element according to one aspect of the present invention includes an electrode body including a laminated positive electrode plate and a negative electrode plate, and the positive electrode plate projects in the first direction from the linear first edge of the positive electrode plate. The negative electrode plate includes a positive electrode tab, the negative electrode plate includes a negative electrode tab protruding in the first direction from a linear second edge of the positive electrode plate, and the second edge is in the first direction rather than the first edge. The positive electrode tab has a first rounded portion with a radius at the proximal end, and the negative electrode tab has a second rounded portion with a radius at the proximal end. However, the width of the negative electrode tab in the second direction orthogonal to the first direction is equal to or less than the width in the second direction at the protruding portion of the positive electrode tab protruding from the second edge.

The width of the negative electrode tab on the tip side of the second rounded portion in the second direction orthogonal to the first direction is the width of the positive electrode tab on the tip side of the first rounded portion in the second direction. May be smaller than.

The positive electrode plate and the negative electrode plate are wound, and the winding axis of the electrode body may be along the first direction.

The positive electrode plate and the negative electrode plate are wound, and a plurality of the positive electrode tabs are arranged at intervals in the second direction, and the positive electrode tab bundles are arranged side by side along the stacking direction. A plurality of the negative electrode tabs are formed and arranged at intervals in the second direction, and are arranged side by side along the stacking direction to form a negative electrode tab bundle, and the positive electrode tab bundle and the negative electrode tab are formed. The bundles may be located apart in the second direction.

At least one of each of the plurality of positive electrode tabs constituting the positive electrode tab bundle and each of the plurality of negative electrode tabs constituting the negative electrode tab bundle may be positioned so as to be displaced in the second direction.

The power storage element further includes a container, and the electrode body may be housed in the container with the positive electrode tab bundle and the negative electrode tab bundle bent.

The power storage element further includes a container and a gas discharge valve provided on the wall portion of the container facing the positive electrode tab and the negative electrode tab, and the gas discharge valve is more than the negative electrode tab in the second direction. It may be located near the positive electrode tab.

The positive electrode tab and the negative electrode tab may be arranged at positions that do not overlap with the gas discharge valve when viewed from the wall portion toward the positive electrode tab and the negative electrode tab.

According to the power storage element according to the present invention, it is possible to widen the tolerance of stacking accuracy of the negative electrode tab of the negative electrode plate.

It is a perspective view which shows typically the appearance of the power storage element which concerns on embodiment of this invention. It is an exploded perspective view of the power storage element of FIG. It is an exploded perspective view of the lid body of FIG. 2 and the components around it. It is a perspective view of the electrode body which shows by developing a part of the electrode body of FIG. FIG. 5 is a cross-sectional view of the power storage element seen from the direction V along the lid of the power storage element and passing near the end in the winding axis direction of the electrode body. 4 is a cross-sectional side view of the cross section of the electrode body along the direction perpendicular to the stacking direction of the positive electrode plate and the negative electrode plate of FIG. 4 and passing through the positive electrode tab bundle and the negative electrode tab bundle as viewed from the direction VI. FIG. 5 is a cross-sectional side view showing a cross section of an electrode body of the power storage element according to the first modification of the power storage element according to the embodiment in the same manner as in FIG. It is sectional drawing side view which shows the cross section of the electrode body of the power storage element of the modification 2 of the power storage element which concerns on embodiment in the same manner as FIG.

Hereinafter, the power storage element according to the embodiment of the present invention will be described with reference to the drawings. It should be noted that all of the embodiments described below show comprehensive or specific examples. Numerical values, shapes, materials, components, arrangement positions and connection forms of components, steps (processes), order of steps, 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 claims indicating the highest level concept are described as arbitrary components. Further, each figure in the attached drawings is a schematic view and is not necessarily exactly illustrated. Further, in each figure, the same or similar components are designated by the same reference numerals. Further, in the following description of the embodiment, expressions with "abbreviations" such as substantially parallel and substantially orthogonal may be used. For example, substantially parallel means not only completely parallel, but also substantially parallel, that is, including a difference of, for example, about several percent. The same applies to other expressions with "abbreviations".

[Embodiment]
The configuration of the power storage element 100 according to the embodiment will be described. FIG. 1 is a perspective view schematically showing the appearance of the power storage element 100 according to the embodiment. As shown in FIG. 1, the power storage element 100 has a flat rectangular parallelepiped outer shape. The power storage element 100 is a rechargeable secondary battery. For example, the power storage element 100 is a non-aqueous electrolyte secondary battery such as a lithium ion secondary battery. However, the power storage element 100 is not limited to the non-aqueous electrolyte secondary battery, and may be a secondary battery other than the non-aqueous electrolyte secondary battery, and can store electricity without being charged by the user. It may be a usable primary battery or a capacitor. Further, the outer shape of the power storage element 100 is not limited to the rectangular parallelepiped shape, and may be a shape including a curved portion such as a columnar shape or an oblong columnar shape.

Referring to FIGS. 1 and 2, the power storage element 100 includes a flat rectangular parallelepiped container 10, an electrode body 20 contained in the container 10, and a positive electrode terminal 30 and a negative electrode terminal 40. Note that FIG. 2 is an exploded perspective view of the power storage element 100 of FIG. The container 10 has a bottomed square cylindrical container body 11 and an elongated rectangular plate-shaped lid 12 capable of closing the elongated rectangular opening 11a of the container body 11. The container body 11 has a flat rectangular parallelepiped outer shape. The container body 11 and the lid 12 are fixed to each other in an airtight state by a joining method such as welding. Without limitation, the container body 11 and the lid 12 can be made of weldable metals such as aluminum, aluminum alloys and stainless steel. Here, the lid body 12 is an example of the wall of the container.

An electrolyte such as an electrolytic solution (in this embodiment, a non-aqueous electrolytic solution) is sealed inside the container 10 together with the electrode body 20, but the illustration of the electrolyte is omitted. As the electrolyte sealed in the container 10, various types can be selected without particular limitation as long as the performance of the power storage element 100 is not impaired.

The positive electrode terminal 30 and the negative electrode terminal 40 are arranged on the outer surface 12a of the lid body 12. The conductive positive electrode terminal 30 and the negative electrode terminal 40 each penetrate the lid 12 and protrude from the inner surface 12b on the opposite side of the outer surface 12a of the lid 12, and on the opposite side, the conductive positive electrode lead plate. It is connected to 51 and the negative electrode lead plate 61. The positive electrode lead plate 51 and the negative electrode lead plate 61 are further connected to the electrode body 20. The electrode body 20 is housed in the container body 11 together with the positive electrode lead plate 51 and the negative electrode lead plate 61. The positive electrode lead plate 51 and the negative electrode lead plate 61 are not essential. Further, in order to electrically insulate between the electrode body 20 and the container body 11, the electrode body 20 may be covered with an insulating film or the like. A cushioning material such as a spacer may be provided between the electrode body 20 and the container body 11.

Further, a gas discharge valve 70 is formed on the outer surface 12a of the lid body 12. The gas discharge valve 70 is arranged between the positive electrode terminal 30 and the negative electrode terminal 40, and is further located closer to the positive electrode terminal 30 than the negative electrode terminal 40. The gas discharge valve 70 is configured to break when the pressure of the gas in the container 10 rises above a predetermined pressure and discharge the gas to the outside of the container 10. In the present embodiment, the gas discharge valve 70 has a structure integrally molded with the lid body 12.

The gas discharge valve 70 includes a weakened portion 71 formed by reducing the thickness of a part of the lid body 12. In the present embodiment, the weakened portion 71 is formed by recessing the outer surface 12a and the inner surface 12b of the lid 12 so as to form an oval flat shape at positions facing each other. The planar shape is a shape when the weakened portion 71 is viewed in a direction perpendicular to the outer surface 12a and the inner surface 12b. When a predetermined pressure acts on the gas discharge valve 70 due to an increase in pressure in the container 10, the weakened portion 71 breaks and an opening as a pressure relief hole is formed. Further, the weakened portion 71 may be configured to be easily broken at the portion of the groove portion 72 by cutting the groove portion 72. The groove portion 72 has a shape in which two grooves intersect in the present embodiment, but has a shape in which a plurality of grooves intersect. At the intersection of the grooves, the weakened portion 71 is likely to break. The pressure at which the gas discharge valve 70 opens can be controlled by the shape of the weakened portion in the weakened portion 71, the member thickness of the weakened portion, the shape of the groove portion, the depth of the groove portion, and the like.

Referring to FIG. 3, the positive electrode terminal 30 is connected to the positive electrode lead plate 51 via the positive electrode current collector 50, and the negative electrode terminal 40 is connected to the negative electrode lead plate 61 via the negative electrode current collector 60. Note that FIG. 3 is an exploded perspective view of the lid body 12 of FIG. 2 and its peripheral components. The positive electrode lead plate 51 constitutes a part of the components of the positive electrode current collector 50, and the negative electrode lead plate 61 constitutes a part of the components of the negative electrode current collector 60. The positive electrode current collector 50 is a plate-shaped member having conductivity and rigidity, and is made of the same material as the constituent material of the positive electrode plate of the electrode body 20, which will be described later. For example, the positive electrode current collector 50 is made of a metal such as aluminum or an aluminum alloy. The negative electrode current collector 60 is a plate-shaped member having conductivity and rigidity, and is made of the same material as the constituent material of the negative electrode plate of the electrode body 20, which will be described later. For example, the negative electrode current collector 60 is made of a metal such as copper or a copper alloy.

Further, a plate-shaped upper insulating member 31 is provided between the positive electrode terminal 30 and the lid 12, and electrically insulates them from each other, and the plate-shaped lower insulating member 32 collects electricity between the lid 12 and the positive electrode. It is provided between the body 50 and electrically insulates them from each other. A plate-shaped upper insulating member 41 is provided between the negative electrode terminal 40 and the lid 12, and electrically insulates them from each other. The plate-shaped lower insulating member 42 is the lid 12 and the negative electrode current collector 60. It is provided between and electrically insulates them from each other. The upper insulating members 31 and 41 and the lower insulating members 32 and 42 are all formed of an electrically insulating material such as resin, and are, for example, PPS (polyphenylene sulfide), PEEK (polyetheretherketone), PP. It is composed of a gasket made of (polypropylene), PFA (tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer) or the like.

The positive electrode terminal 30 and the negative electrode terminal 40 have plate-shaped terminal bodies 30a and 40a, and cylindrical shaft portions 30b and 40b extending from the terminal bodies 30a and 40a, respectively. The shaft portion 30b of the positive electrode terminal 30 extends through the upper insulating member 31, the lid 12, the lower insulating member 32, and the positive electrode current collector 50. The shaft portion 40b of the negative electrode terminal 40 extends through the upper insulating member 41, the lid 12, the lower insulating member 42, and the negative electrode current collector 60. In the present embodiment, the shaft portions 30b and 40b are crimped by being plastically deformed so that the tips protruding from the positive electrode current collector 50 and the negative electrode current collector 60 are pressed and expanded in diameter, respectively. Is connected to the positive electrode current collector 50 and the negative electrode current collector 60. As a result, the terminal body 30a of the positive electrode terminal 30 and the positive electrode current collector 50 are physically and electrically connected to each other while sandwiching the upper insulating member 31, the lid body 12, and the lower insulating member 32. The terminal body 40a of the negative electrode terminal 40 and the negative electrode current collector 60 are physically and electrically connected to each other while sandwiching the upper insulating member 41, the lid body 12, and the lower insulating member 42.

The connection structure between the terminal body 30a of the positive electrode terminal 30 and the positive electrode current collector 50 and the connection structure between the terminal body 40a of the negative electrode terminal 40 and the negative electrode current collector 60 are formed by caulking the shaft portions 30b and 40b. Not limited. The connection structure is a structure in which the terminal body 30a or 40a is connected to the positive electrode current collector 50 or the negative electrode current collector 60 while sandwiching the upper insulating member 31 or 41, the lid body 12, and the lower insulating member 32 or 42. It should be. For example, bolts and nuts may be used instead of the shaft portion 30b or 40b, and the shaft portion 30b or 40b may be welded to the positive electrode current collector 50 or the negative electrode current collector 60. Alternatively, the positive electrode terminal 30 and the positive electrode current collector 50 may be integrally formed, and the negative electrode terminal 40 and the negative electrode current collector 60 may be integrally formed. In this case, the upper insulating member 31 and the lower insulating member 32 may be integrally molded with the lid 12, the positive electrode terminal 30, and the positive electrode current collector 50 by an integrated molding method such as insert molding. Similarly, the upper insulating member 41 and the lower insulating member 42 may be integrally molded with the lid body 12, the negative electrode terminal 40, and the negative electrode current collector 60 by an integrated molding method such as insert molding.

In the present embodiment, the positive electrode lead plate 51 and the negative electrode lead plate 61 are formed of a plate material bent in a U shape. The positive electrode lead plate 51 and the negative electrode lead plate 61 are formed of the same materials as the positive electrode current collector 50 and the negative electrode current collector 60, respectively. The shapes of the positive electrode lead plate 51 and the negative electrode lead plate 61 are not limited to the U shape, and as described below, the connection between the positive electrode current collector 50 and the electrode body 20 and the negative electrode current collection Any structure may be used as long as it has a structure for relaying the connection between the body 60 and the electrode body 20.

A flat plate-shaped connecting portion 51a and a connecting portion 51b forming two U-shaped opposite side portions of the positive electrode lead plate 51 are connected to the positive electrode current collector 50 and the electrode body 20, respectively. The positive electrode lead plate 51 relays the connection between the positive electrode current collector 50 and the electrode body 20. A flat plate-shaped connecting portion 61a and a connecting portion 61b forming two U-shaped opposite side portions of the negative electrode lead plate 61 are connected to the negative electrode current collector 60 and the electrode body 20, respectively. The negative electrode lead plate 61 relays the connection between the negative electrode current collector 60 and the electrode body 20. For the connection between the connecting portion 51a and the positive electrode current collector 50 and the connection between the connecting portion 61a and the negative electrode current collector 60, welding such as ultrasonic welding or resistance welding can be used. For the connection between the connecting portion 51b and the electrode body 20, and the connection between the connecting portion 61b and the electrode body 20, welding such as ultrasonic welding or resistance welding, bonding by plastic deformation such as bonding by caulking, or the like can be used. The positive electrode current collector 50, the negative electrode current collector 60, and the electrode body 20 may be connected by using the above-mentioned connection method without providing the positive electrode lead plate 51 and the negative electrode lead plate 61.

The configuration of the electrode body 20 will be described with reference to FIGS. 2 and 4. Note that FIG. 4 is a perspective view of the electrode body 20 in which a part of the electrode body 20 of FIG. 2 is developed and shown. The electrode body 20 is a power storage element (also called a power generation element) capable of storing electricity. The electrode body 20 has a sheet-shaped positive electrode plate 21 having a long rectangular strip-shaped flat shape, a sheet-shaped negative electrode plate 22 having a long rectangular strip-shaped flat shape, and a long rectangular strip-shaped flat shape. The two sheet-shaped separators 23 are included in a layered manner.

In the electrode body 20, one separator 23, the negative electrode plate 22, the other separator 23, and the positive electrode plate 21 are laminated in this order in a layered manner, and the winding axis A is centered in the winding direction B as shown in FIG. It is formed by being wound in multiple spirals together. The winding shaft A is a virtual shaft shown by a alternate long and short dash line in FIGS. 2 and 4, and the electrode body 20 has a substantially symmetrical configuration with respect to the winding shaft A. Although not limited to this, in the present embodiment, the electrode body 20 has a flat outer shape having an oval shape having a flat cross section perpendicular to the winding axis A. However, the cross-sectional shape of the electrode body 20 may be other than an oval shape, and may be a circle, an ellipse, a rectangle, or another polygon.

The positive electrode plate 21 is formed by coating a positive electrode base material, which is a long rectangular strip-shaped metal foil made of a metal such as aluminum or an aluminum alloy, and substantially the entire surface of the wide main surface on both sides of the positive electrode base material. It includes the formed positive electrode active material layer (indicated by diagonal lines in FIG. 4). The negative electrode plate 22 is formed by coating a negative electrode base material, which is a long rectangular strip-shaped metal foil made of a metal such as copper or a copper alloy, and substantially the entire surface of the wide main surface on both sides of the negative electrode base material. It includes the formed negative electrode active material layer (indicated by diagonal lines in FIG. 4). As the positive electrode active material used for the positive electrode active material layer or the negative electrode active material used for the negative electrode active material layer, any known material can be appropriately used as long as it is a positive electrode active material or a negative electrode active material capable of storing and releasing lithium ions. In the present embodiment, the positive electrode active material layer and the negative electrode active material layer are formed on the main surfaces on both sides of the positive electrode base material and the negative electrode base material, respectively, but are formed only on one main surface. May be good. The separator 23 is a microporous sheet made of a material having electrical insulation such as resin.

A plurality of rectangular foil-shaped positive electrode tabs 21c are provided as the first direction on the first edge 21a of one of the two linear edges 21a and 21b along the longitudinal direction and the winding direction B of the positive electrode plate 21. It is formed so as to project in a direction substantially perpendicular to the first edge 21a of the above. The plurality of positive electrode tabs 21c are arranged at intervals along the first edge 21a. The positive electrode tab 21c extends continuously and integrally from the positive electrode base material, and forms a part of the positive electrode base material. The positive electrode tab 21c is made of the same material as the positive electrode base material, and the positive electrode active material layer is not formed on the positive electrode tab 21c. In the present embodiment, one positive electrode tab 21c is arranged per one turn of the positive electrode plate 21 in the electrode body 20. In the electrode body 20 after winding, the plurality of positive electrode tabs 21c are gathered and located at one place to form a positive electrode tab bundle 21d. In the positive electrode tab bundle 21d, the plurality of positive electrode tabs 21c are located substantially in a line in the stacking direction of the multiple layers formed by the wound positive electrode plate 21, the negative electrode plate 22, and the separator 23. The positions of the plurality of positive electrode tabs 21c may deviate from each other and from predetermined positions in the winding direction B, that is, the direction along the first edge 21a in the winding process of the electrode body 20.

A plurality of rectangular foil-shaped negative electrode tabs 22c are provided as the first direction on the second edge 22a of one of the two linear edges 22a and 22b along the longitudinal direction and the winding direction B of the negative electrode plate 22. It is formed so as to project in a direction substantially perpendicular to the second edge 22a of the above. The plurality of negative electrode tabs 22c are arranged at intervals along the second edge 22a. The negative electrode tab 22c extends continuously and integrally from the negative electrode base material, and forms a part of the negative electrode base material. The negative electrode tab 22c is made of the same material as the negative electrode base material, and the negative electrode active material layer is not formed on the negative electrode tab 22c. In the present embodiment, one negative electrode tab 22c is arranged per one turn of the negative electrode plate 22 in the electrode body 20. In the wound electrode body 20, the plurality of negative electrode tabs 22c are gathered and located at one place to form a negative electrode tab bundle 22d. In the negative electrode tab bundle 22d, the plurality of negative electrode tabs 22c are located substantially in a line in the stacking direction of the wound positive electrode plate 21, the negative electrode plate 22, and the separator 23. In the process of winding the electrode body 20, the positions of the plurality of negative electrode tabs 22c may deviate from each other and from predetermined positions in the winding direction B, that is, in the direction along the second edge 22a. The negative electrode tab bundle 22d is arranged along the second edge 22a away from the positive electrode tab bundle 21d.

The number of positive electrode tabs 21c and negative electrode tabs 22c arranged per turn of each of the positive electrode plate 21 and the negative electrode plate 22 is not limited to one. The quantity of the positive electrode tab bundle 21d and the negative electrode tab bundle 22d is also not limited to one. Further, in the present embodiment, the positive electrode tab 21c and the negative electrode tab 22c have a rectangular planar shape, but may have any shape.

The positive electrode plate 21 and the negative electrode plate 22 are overlapped so that their edges extend along each other for winding. At this time, the positive electrode tab 21c and the negative electrode tab 22c are located on the same side with respect to the overlapping portion of the positive electrode plate 21 and the negative electrode plate 22. That is, the first edge 21a of the positive electrode plate 21 and the second edge 22a of the negative electrode plate 22 are located adjacent to each other and substantially parallel to each other, and the edge 21b of the positive electrode plate 21 and the edge 22b of the negative electrode plate 22 are adjacent to each other and substantially parallel to each other. Located approximately parallel.

The two separators 23 are arranged on the flat main surfaces on both sides of one negative electrode plate 22, respectively. The entire negative electrode plate 22 excluding the negative electrode tab 22c is covered with the two separators 23, and the negative electrode tab 22c passes between the two separators 23 and protrudes from the separator 23. One positive electrode plate 21 is arranged so as to be overlapped on the separator 23 so as to be located further inside the separator 23 which is adjacent to the negative electrode plate 22 on the inside at the time of winding. The entire positive electrode plate 21 excluding the positive electrode tab 21c is covered with the negative electrode plate 22 and the separator 23, and the positive electrode tab 21c protrudes from the separator 23.

The one positive electrode plate 21, the one negative electrode plate 22, and the two separators 23, which are overlapped as described above, are spirally wound around the winding shaft A in the winding direction B to form electrodes. Form the body 20. In the electrode body 20 after winding, the second edge 22a of the negative electrode plate 22 projects from the inside to the outside of the electrode body 20 in the winding axis A direction from the first edge 21a of the positive electrode plate 21. The tips of the second edges 22a in the winding axis A direction are arranged so as to form a flat surface, and form one end 20a of the electrode body 20 in the winding axis A direction. Further, the edge 22b of the negative electrode plate 22 projects from the inside to the outside of the electrode body 20 in the winding axis A direction from the edge 21b of the positive electrode plate 21. The tips of the edges 22b in the winding axis A direction are arranged so as to form a flat surface, and form the other end 20b of the electrode body 20 in the winding axis A direction.

Further, in the electrode body 20 after winding, the positive electrode plate 21, the negative electrode plate 22, and the separator 23 laminated by winding form a wall-like body extending along the winding direction B. The wall-shaped body is located so as to face each other across the winding shaft A and is wide and flat, and the two flat portions 20c and 20d are located so as to face each other across the winding shaft A and are curved in a semicircular shape. It is composed of two curved portions 20e and 20f. The flat portions 20c and 20d extend substantially parallel to each other. In the curved portions 20e and 20f, the flat portion 20c and the flat portion 20d are connected to each other at both ends, respectively. In the electrode body 20, the end portion 20a, the positive electrode tab bundle 21d and the negative electrode tab bundle 22d face the lid body 12, and the flat portions 20c and 20d and the curved portions 20e and 20f face the side wall of the container body 11, and the container 10 It is housed inside. That is, the electrode body 20 is housed in the container 10 with the winding shaft A oriented substantially perpendicular to the lid body 12. Further, in the present embodiment, the positive electrode tab bundle 21d and the negative electrode tab bundle 22d are arranged on the flat portion 20d, but the present invention is not limited thereto.

Further, the positive electrode tab bundle 21d of the electrode body 20 after winding is connected to the connecting portion 51b of the positive electrode lead plate 51 shown in FIG. 3 in a state of being bent in the direction from the flat portion 20d toward the flat portion 20c. The negative electrode tab bundle 22d is connected to the connecting portion 61b of the negative electrode lead plate 61 shown in FIG. 3 in a state of being bent in the direction from the flat portion 20d toward the flat portion 20c. As a result, the positive electrode terminal 30 is physically and electrically connected to the positive electrode plate 21 of the electrode body 20 via the positive electrode current collector 50 and the positive electrode lead plate 51. The negative electrode terminal 40 is physically and electrically connected to the negative electrode plate 22 of the electrode body 20 via the negative electrode current collector 60 and the negative electrode lead plate 61. The U-shaped lead plates 51 and 61 are extended so as to have a shape such as an L shape until the connection with the positive electrode current collector 50 and the negative electrode current collector 60 or the connection with the electrode body 20. It may be arranged in a U-shape after the connection is completed.

With reference to FIGS. 2, 3 and 5, the gas discharge valve 70 formed on the lid 12 is a bundle of positive electrode tabs when viewed from the lid 12 toward the container body 11, that is, in the winding axis A direction. It is arranged so as not to overlap with the 21d and the negative electrode tab bundle 22d. Further, the gas discharge valve 70 is arranged so as not to overlap the positive electrode current collector 50, the positive electrode lead plate 51, the negative electrode current collector 60, the negative electrode lead plate 61, the upper insulating members 31 and 41, and the lower insulating members 32 and 42. May be done. 5 is a cross-sectional view of the power storage element 100 seen from the direction V along the lid 12 of the power storage element 100 of FIG. 1 and passing near the end portion 20a of the electrode body 20 in the winding axis A direction. .. Further, the direction from the lid body 12 toward the container body 11 is also a direction from the lid body 12 toward the positive electrode tab bundle 21d and the negative electrode tab bundle 22d.

The gas discharge valve 70 is located closer to the positive electrode tab bundle 21d than the negative electrode tab bundle 22d in the longitudinal direction of the lid 12 from the negative electrode terminal 40 to the positive electrode terminal 30. As a result, the gas discharge valve 70 is located closer to the positive electrode current collector 50 and the positive electrode lead plate 51 than to the negative electrode current collector 60 and the negative electrode lead plate 61. The plurality of negative electrode tabs 22c of the negative electrode tab bundle 22d having the positional relationship as described above with the gas discharge valve 70 are arranged so as to be displaced from each other in the winding direction B of the electrode body 20, that is, in the direction along the flat portion 20d. Even in such a case, it is possible to suppress the position where it overlaps with the gas discharge valve 70.

The detailed configuration of the positive electrode tab 21c and the negative electrode tab 22c will be described with reference to FIG. FIG. 6 shows a cross section of the electrode body 20 along the direction perpendicular to the stacking direction of the positive electrode plate 21 and the negative electrode plate 22 of the electrode body 20 of FIG. 4 and passing through the positive electrode tab bundle 21d and the negative electrode tab bundle 22d in the direction VI, that is, the electrode. It is a cross-sectional side view seen from the flat portion 20d of the body 20 toward the flat portion 20c. Note that FIG. 6 is drawn with the separator 23 omitted.

The positive electrode tab 21c integrally includes a main body portion 21ca and first rounded portions 21cba and 21cbb that corner the root portions of both side portions of the main body portion 21ca with a radius. The main body 21ca extends from the first edge 21a in the winding axis A direction, that is, in a direction substantially perpendicular to the first edge 21a, and has a rectangular planar shape. The first rounded portions 21cba and 21cbb are adjacent to the base end 21caa, which is the end portion of the main body portion 21ca on the first edge 21a side, at both ends. The base end 21caa is also a root portion of the main body portion 21ca. The first rounded portions 21cba and 21cbb are adjacent to the side portions 21cab and 21cac of the main body portion 21ca along the projecting direction of the main body portion 21ca and the first edge 21a, respectively. In this embodiment, the side portions 21 cab and 21 cc extend substantially parallel to each other, but are not limited thereto.

The first rounded portions 21 cba and 21 cbb are located at the corners of the side portions 21 cab and 21 cc and the first edge 21 a, respectively, and are portions that cut the corners in a concave curved shape in the recessed direction of the corners. The first rounded portions 21cba and 21cbb form the edges of the rounded and curved positive electrode tab 21c. In the present embodiment, the first rounded portions 21cba and 21cbb form an arcuate edge of the positive electrode tab 21c, that is, a rounded edge. The edges formed by the first rounded portions 21cba and 21cbb respectively extend smoothly and continuously from the side portions 21cab and 21cc, and smoothly and continuously extend from the first edge 21a. The first rounded portions 21cba and 21cbb may form curved edges with the same radius of curvature, or curved edges with different radius of curvature. The first rounded portions 21cba and 21cbb may have the same shape and dimensions, or may have different shapes and dimensions. Further, the corners of the tip 21cad of the main body 21ca and the side portions 21cab and 21cac located at positions facing the base end 21ca are chamfered in a convex curved shape in the protruding direction of the corners, respectively.

In the present embodiment, when the positive electrode tab 21c is viewed from the flat portion 20d of the electrode body 20 toward the flat portion 20c in the stacking direction of the positive electrode plate 21 and the negative electrode plate 22, the first rounded portions 21cba and 21cbb are the negative electrodes. It is located between the second edge 22a of the plate 22 and the first edge 21a of the positive electrode plate 21. That is, the first rounded portions 21cba and 21cbb do not protrude more than the second edge 22a in the winding axis A direction, which is a direction substantially perpendicular to the edges 21a and 22a.

The positive electrode tab 21c has a maximum width B1 as a width in the direction along the first edge 21a. The maximum width B1 includes the width B1a at the base end 21caa of the main body portion 21ca in the direction along the first edge 21a and the widths B1b and B1c of the first rounded portions 21cba and 21cbb in the direction along the first edge 21a, respectively. Is the sum of. That is, the maximum width B1 is a width based on the relationship of B1 = B1a + B1b + B1c. In the present embodiment, the main body portion 21ca has substantially the same width B1a from the base end 21caa to the tip end 21cad. Further, the protruding portion of the positive electrode tab 21c that protrudes from the second edge 22a of the negative electrode plate 22 in the winding axis A direction is formed by the protruding portion 21cae that is a part of the main body portion 21ca. The maximum width B1d of the protruding portion of the positive electrode tab 21c in the direction along the first edge 21a is equal to the width B1a of the protruding portion 21cae.

The width between the side portions 21cab and 21cac of the main body portion 21ca of the positive electrode tab 21c may change in the winding axis A direction. In this case, the maximum width B1 can be the sum of the width of the main body portion 21ca at the base end 21caa and the widths B1b and B1c of the first rounded portions 21cba and 21cbb. The maximum width B1d of the protruding portion of the positive electrode tab 21c is the maximum width of the protruding portion 21cae of the main body portion 21ca. Further, the first rounded portions 21cba and 21cbb may protrude from the second edge 22a in the winding axis A direction. In this case, the maximum width B1d of the protruding portion of the positive electrode tab 21c can be the sum of the width of the protruding portions of the first rounded portions 21cba and 21cbb and the width of the protruding portion 21cae of the main body portion 21ca.

The negative electrode tab 22c integrally includes a main body portion 22ca and second rounded portions 22cba and 22cbb that corner the root portions of both side portions of the main body portion 22ca with a radius. The main body portion 22ca extends from the second edge 22a of the negative electrode plate 22 in the winding axis A direction, that is, in a direction substantially perpendicular to the second edge 22a, and has a rectangular planar shape. The second rounded portions 22cba and 22cbb are adjacent to the base end 22caa on the second edge 22a side of the main body portion 22ca at both ends. The base end 22ca is also the root portion of the main body 22ca. The second rounded portions 22cba and 22cbb are adjacent to the side portions 22cab and 22cac of the main body portion 22ca along the projecting direction of the main body portion 22ca and the second edge 22a, respectively. In this embodiment, the side portions 22 cab and 22 cc extend substantially parallel to each other, but are not limited thereto.

The second rounded portions 22 cba and 22 cbb are located at the corners of the side portions 22 cab and 22 cc and the second edge 22 a, respectively, and are portions that cut the corners in a concave curved shape in the recessed direction of the corners. The second rounded portions 22cba and 22cbb form the edge of the negative electrode tab 22c having a rounded curved shape. In the present embodiment, the second rounded portions 22cba and 22cbb form an arcuate edge of the negative electrode tab 22c, that is, a rounded edge. The edges formed by the second rounded portions 22cba and 22cbb respectively extend smoothly and continuously from the side portions 22cab and 22cc, and smoothly and continuously extend from the second edge 22a. The second rounded portions 22cba and 22cbb may form curved edges with the same radius, or may form curved edges with different radius. The second rounded portions 22cba and 22cbb may have the same shape and dimensions, or may have different shapes and dimensions. Further, the corner portions of the tip 22cad of the main body portion 22ca and the side portions 22cab and 22cac, which are located at positions facing the base end 22caa, are chamfered in a convex curved shape in the protruding direction of the corner portions, respectively.

The negative electrode tab 22c has a maximum width B2 as a width in the direction along the second edge 22a. The maximum width B2 includes the width B2a at the base end 22caa of the main body portion 22ca in the direction along the second edge 22a and the widths B2b and B2c of the second rounded portions 22cba and 22cbb in the direction along the second edge 22a, respectively. Is the sum of. That is, the maximum width B2 is a width based on the relationship of B2 = B2a + B2b + B2c. In the present embodiment, the main body portion 22ca has substantially the same width B2a from the base end 22caa to the tip end 22cad.

In the present embodiment, the width B2a of the main body 22ca of the negative electrode tab 22c is equivalent to the width B1a of the main body 21ca of the positive electrode tab 21c. The radii of curvature of the second rounded portions 22cba and 22cbb of the negative electrode tab 22c are both smaller than the radii of curvature of the first rounded portions 21cba and 21cbb of the positive electrode tab 21c. Therefore, the widths B2b and B2c of the second rounded portions 22cba and 22cbb are all smaller than the widths B1b and B1c of the first rounded portions 21cba and 21cbb. Therefore, the negative electrode tab 22c has a smaller maximum width B2 of the portion protruding from the second edge 22a, that is, the portion protruding from the end portion 20a of the electrode body 20, as compared with the case where the negative electrode tab 22c is formed with the same shape and dimensions as the positive electrode tab 21c. It can be suppressed. As a result, even when the positions of the plurality of negative electrode tabs 22c are deviated from each other in the direction along the second edge 22a, that is, in the winding direction, the area occupied by the negative electrode tab bundle 22d in the direction along the second edge 22a can be suppressed to a small size. ..

Further, the positive electrode tab 21c can suppress the width B1d of the portion protruding from the second edge 22a and the end portion 20a of the electrode body 20 to a small width B1a of the main body portion 21ca. Therefore, even when the positions of the plurality of positive electrode tabs 21c are deviated from each other in the direction along the second edge 22a, the region occupied by the positive electrode tab bundle 21d in the direction along the second edge 22a can be kept small.

Further, the maximum width B2 of the negative electrode tab 22c on the end 20a of the electrode body 20 is larger than the maximum width B1d, that is, the width B1a of the portion of the positive electrode tab 21c protruding from the end 20a of the electrode body 20. However, as shown in FIG. 5, the negative electrode tab bundle 22d is arranged in the flat portion 20d along the second edge 22a of the negative electrode plate 22, that is, the positive electrode tab bundle 21d, the gas discharge valve 70, and the negative electrode tab bundle 22d are arranged. It is located at a position farther from the gas discharge valve 70 than the positive electrode tab bundle 21d in the direction. Therefore, the positive electrode tab bundle 21d, the gas discharge valve 70, and the negative electrode tab bundle 22d do not overlap each other when viewed in the winding axis A direction, and the direction along the second edge 22a at the flat portion 20d, that is, the negative electrode terminal. The region that the negative electrode tab bundle 22d can occupy in the direction from 40 toward the positive electrode terminal 30 is larger than that of the positive electrode tab bundle 21d. As a result, the allowable amount of positional deviation from the preset arrangement positions for the plurality of negative electrode tabs 22c is larger than that for the plurality of positive electrode tabs 21c. Therefore, it becomes easy to prevent the positive electrode tab bundle 21d, the negative electrode tab bundle 22d, and the gas discharge valve 70 from overlapping each other when viewed in the winding axis A direction. For example, if the positive electrode tab bundle 21d or the negative electrode tab bundle 22d overlaps with the gas discharge valve 70 in the winding shaft A direction, the operation of the gas discharge valve 70 may be adversely affected.

As described above, the power storage element 100 according to the present embodiment includes an electrode body 20 including a laminated positive electrode plate 21 and a negative electrode plate 22. The positive electrode plate 21 includes a positive electrode tab 21c protruding in the first direction from the linear first edge 21a of the positive electrode plate 21, and the negative electrode plate 22 is in the first direction from the linear second edge 22a of the negative electrode plate 22. Includes a protruding negative electrode tab 22c. The second edge 22a is positioned so as to project in the first direction from the first edge 21a. The positive electrode tab 21c has first rounded portions 21cba and 21cbb at its base end 21caa, and the negative electrode tab 22c has a curvature smaller than that of the first rounded portions 21cba and 21cbb at its base end 22caa. It has a second rounded portion 22 cba and 22 cbb with a radius radius.

In the above configuration, by reducing the radius of curvature of the radius of the radius of the second rounded portion 22cba and 22cbb of the negative electrode tab 22c, the maximum width of the negative electrode tab 22c along the second edge 22a can be suppressed to be small. Further, at least a part of the first rounded portions 21cba and 21cbb of the positive electrode tab 21c is located between the second edge 22a and the first edge 21a. Therefore, the width of the portion of the positive electrode tab 21c that protrudes from the second edge 22a can be suppressed to a small size. Therefore, the width of the portion of the positive electrode tab 21c and the negative electrode tab 22c that protrudes from the second edge 22a can be suppressed to a small size. As a result, even if the positions of the positive electrode tab 21c and the negative electrode tab 22c deviate from the predetermined arrangement positions in the direction along the second edge 22a during lamination, they protrude from the second edge 22a of the positive electrode tab 21c and the negative electrode tab 22c. The area that can be occupied by the part to be used is kept small. Therefore, with respect to the misalignment of the positive electrode tab 21c and the negative electrode tab 22c, the tolerance of the lamination accuracy of the positive electrode plate 21 and the negative electrode plate 22 is expanded.

Further, since the maximum width of the negative electrode tab 22c is controlled by adjusting the radius of curvature of the radius of the second rounded portions 22cba and 22cbb, the main body portion of the negative electrode tab 22c excluding the second rounded portions 22cba and 22cbb. A wide width of 22 ca can be secured. Therefore, it is possible to secure a sufficient connection area between the negative electrode tab 22c and the negative electrode lead plate 61.

In the electrode body 20 of the power storage element 100 according to the embodiment, the positive electrode plate 21 and the negative electrode plate 22 are wound, and the winding shaft A of the electrode body 20 is a positive electrode tab from the first edge 21a of the positive electrode plate 21. Along the first direction, which is the protruding direction of 21c. In the above configuration, in the electrode body 20 around which the positive electrode plate 21 and the negative electrode plate 22 are wound, the tension applied to the positive electrode plate 21 and the negative electrode plate 22 at the time of winding and the thickness of the positive electrode plate 21, the negative electrode plate 22 and the separator 23 The positions of the positive electrode tab 21c and the negative electrode tab 22c can be changed according to the variation of the above. In order to prevent the region where the positive electrode tab 21c and the negative electrode tab 22c can exist from becoming excessive in the electrode body 20 as described above, the positive electrode tab 21c and the negative electrode tab 22c project from the second edge 22a of the negative electrode plate 22. Keeping the width of the portion small is particularly effective.

In the electrode body 20 of the power storage element 100 according to the embodiment, the positive electrode plate 21 and the negative electrode plate 22 are wound. A plurality of positive electrode tabs 21c are arranged at intervals in the second direction orthogonal to the protruding direction of the positive electrode tab 21c from the first edge 21a of the positive electrode plate 21, and are arranged side by side along the stacking direction. A positive electrode tab bundle 21d is formed. A plurality of negative electrode tabs 22c are arranged at intervals in the second direction and are arranged side by side along the stacking direction to form a negative electrode tab bundle 22d. Further, the positive electrode tab bundle 21d and the negative electrode tab bundle 22d are located apart from each other in the second direction. In the above configuration, the positive electrode tab bundle 21d and the negative electrode tab bundle 22d are electrodes along the winding direction by suppressing the width of the portion of the positive electrode tab 21c and the negative electrode tab 22c that protrudes from the second edge 22a of the negative electrode plate 22 to be small. It is possible to reduce the area that can be occupied on the body 20.

In the electrode body 20 of the power storage element 100 according to the embodiment, at least one of each of the plurality of positive electrode tabs 21c constituting the positive electrode tab bundle 21d and each of the plurality of negative electrode tabs 22c constituting the negative electrode tab bundle 22d is a positive electrode. It is positioned so as to be offset in the second direction orthogonal to the protruding direction of the positive electrode tab 21c from the first edge 21a of the plate 21. In the above configuration, by suppressing the width of the positive electrode tab 21c and the negative electrode tab 22c on the second edge 22a of the negative electrode plate 22 to be small, which of the plurality of positive electrode tabs 21c and the plurality of negative electrode tabs 22c is determined in the second direction. Even when the position is deviated from the above position, the width of the positive electrode tab bundle 21d and the negative electrode tab bundle 22d along the winding direction that can be occupied on the electrode body 20 can be reduced.

In the power storage element 100 according to the embodiment, the electrode body 20 is housed in the container 10 in a state where the positive electrode tab bundle 21d and the negative electrode tab bundle 22d are bent. In the above configuration, since the positive electrode tab 21c and the negative electrode tab 22c have rounded portions 21cba, 21cbb, 22cba and 22cbb at the base ends at 21caa and 22caa, even if they are housed in the container 10 in a bent state, they are at the base end. Suppresses breakage at 21caa and 22caa.

The power storage element 100 according to the embodiment includes a gas discharge valve 70 provided on the lid 12 of the container 10 facing the positive electrode tab 21c and the negative electrode tab 22c. The gas discharge valve 70 is located closer to the positive electrode tab 21c than the negative electrode tab 22c in the second direction orthogonal to the protruding direction of the positive electrode tab 21c from the first edge 21a of the positive electrode plate 21. In the above configuration, it is possible to prevent the negative electrode tab 22c, which can have a large width of the portion protruding from the second edge 22a, from being located at a position that interferes with the operation of the gas discharge valve 70.

In the power storage element 100 according to the embodiment, the positive electrode tab 21c and the negative electrode tab 22c are arranged at positions that do not overlap with the gas discharge valve 70 when viewed from the lid 12 toward the positive electrode tab 21c and the negative electrode tab 22c. .. In the above configuration, it is possible to prevent the positive electrode tab 21c and the negative electrode tab 22c from being positioned at positions that interfere with the operation of the gas discharge valve 70.

Further, in the electrode body 20 of the power storage element 100 according to the embodiment, the widths B2b and B2c of the second rounded portions 22cba and 22cbb of the negative electrode tab 22c of the negative electrode plate 22 are the first of the positive electrode tab 21c of the positive electrode plate 21. It is smaller than, but not limited to, the widths B1b and B1c of the rounded portions 21cba and 21cbb. The widths B2b and B2c of the second rounded portions 22cba and 22cbb may only be configured so that the maximum width B2 of the negative electrode tab 22c is smaller than the maximum width B1 of the positive electrode tab 21c. For example, the width of one of the second rounded portions 22cba and 22cbb of the negative electrode tab 22c may be larger than the widths B1b and / or B1c of the positive electrode tabs 21c first rounded portions 21cba and 21cbb.

Further, in the electrode body 20 of the power storage element 100 according to the embodiment, the first rounded portions 21cba and 21cbb of the positive electrode tab 21c of the positive electrode plate 21 form an arcuate edge, and the second negative electrode tab 22c of the negative electrode plate 22 is formed. The rounded portions 22cba and 22cbb formed an arcuate edge, but the present invention is not limited to this. The rounded portions 21cba, 21cbb, 22cba and 22cbb may only have a configuration in which the corner portion of the base end of the positive electrode tab 21c or the negative electrode tab 22c is cut into a concave curved shape in the recessed direction of the corner portion. For example, the shape of the edge formed by the rounded portions 21cba, 21cbb, 22cba and 22cbb may not be a constant curvature arc as in the embodiment, but may be a combination of a plurality of curvature arcs. Alternatively, the shape of the edge formed by the rounded portions 21cba, 21cbb, 22cba and 22cbb may be a shape including a part of a curve drawn by various functions. Alternatively, the shape of the edge formed by the rounded portions 21cba, 21cbb, 22cba and 22cbb may partially include a straight line. Such rounded portions 21cba, 21cbb, 22cba and 22cbb may only have a structure in which the positive electrode plate 21 or the negative electrode plate 22 is cut off at the corners of the positive electrode tab 21c or the negative electrode tab 22c so as to suppress breakage. ..

[Modification 1]
As a modification 1 of the power storage element 100 according to the embodiment, the following configuration can be mentioned. Specifically, as shown in FIG. 7, in the electrode body 20 of the power storage element according to the first modification, the maximum width B2 of the negative electrode tab 222c of the negative electrode plate 22 is the negative electrode plate 22 in the positive electrode tab 21c of the positive electrode plate 21. The maximum width of the protruding portion from the second edge 22a of the above is B1d or less. FIG. 7 is a cross-sectional side view showing a cross section of the electrode body 20 of the power storage element of the modification 1 of the power storage element 100 according to the embodiment in the same manner as in FIG. In the following description of the modified example, the components having the same reference numerals as the reference symbols in the above figure are the same or similar components, and thus detailed description thereof will be omitted.

Referring to FIG. 7, the positive electrode tab 21c of the positive electrode plate 21 of the electrode body 20 in the first modification has the same configuration as the positive electrode tab 21c of the electrode body 20 in the embodiment. The negative electrode tab 222c of the negative electrode plate 22 of the electrode body 20 in the first modification has the main body portion 222ca and the second rounded portions 22cba and 22cbb, similarly to the negative electrode tab 22c of the electrode body 20 in the embodiment. There is. The configuration of the main body portion 222ca having a rectangular planar shape is formed to be narrower in the direction along the second edge 22a than the main body portion 22ca of the negative electrode tab 22c in the embodiment. Is different. The configuration of the second rounded portions 22cba and 22cbb of the negative electrode tab 222c is the same as that of the second rounded portions 22cba and 22cbb of the negative electrode tab 22c in the embodiment.

The width B2a2 of the main body portion 222ca in the direction along the second edge 22a is smaller than the width B1a of the main body portion 21ca of the positive electrode tab 21c. The width of the main body portion 222ca B2a2 takes a maximum width B1d value to below the projecting portion from the second edge 22a of the maximum width B2 of the negative electrode tab 222c positive electrode tab 2 1 c. Therefore, the width B2a2 satisfies the relationship of B2a2 + B2b + B2c ≦ B1d (= B1a), that is, the relationship of B2a2 ≦ B1a-B2b-B2c.

By keeping the maximum width B2 of the negative electrode tab 222c small as described above, the region that the negative electrode tab bundle 22d can occupy in the direction along the second edge 22a is kept small. Further, the reduction of the maximum width B2 of the negative electrode tab 222c means that the widths B2b and B2c of the second rounded portions 22cba and 22cbb are reduced from the widths B1b and B1c of the first rounded portions 21cba and 21cbb, and the width of the main body portion 222ca. It is achieved by two factors, by reducing B2a2. Therefore, it is possible to reduce the maximum width B2 of the negative electrode tab 222c while suppressing the reduction amount of the width B2a2 of the main body portion 222ca.

Further, since the other configurations of the power storage element according to the first modification are the same as those of the power storage element 100 according to the embodiment, the description thereof will be omitted. Further, according to the power storage element according to the first modification, the same effect as that of the power storage element 100 according to the embodiment can be obtained. Further, in the electrode body 20 of the power storage element according to the first modification, the maximum width B2 of the negative electrode tab 222c in the second direction orthogonal to the protruding direction of the positive electrode tab 21c from the first edge 21a of the positive electrode plate 21 is the negative electrode plate. It is equal to or less than the maximum width B1d in the second direction in the protruding portion of the positive electrode tab 21c that protrudes from the second edge 22a of 22. In the above configuration, the maximum width B2 of the negative electrode tab 222c on the second edge 22a of the negative electrode plate 22 is suppressed to be small.

Further, in the electrode body 20 of the power storage element according to the first modification, the negative electrode tab 222c on the tip side of the second rounded portion 22cba and 22cbb is in the second direction orthogonal to the protruding direction of the positive electrode tab 21c from the first edge 21a. Has a width of B2a2. The width B2a2 is smaller than the width B1d (= width B1a) in the second direction of the positive electrode tab 21c on the tip side of the first rounded portions 21cba and 21cbb. In the above configuration, the maximum width B2 of the negative electrode tab 222c on the second edge 22a of the negative electrode plate 22 can be easily reduced.

[Modification 2]
As a modification 2 of the power storage element 100 according to the embodiment, the following configuration can be mentioned. Specifically, as shown in FIG. 8, the power storage element according to the modified example 2 is the second rounded portion 22 cba and 22 cbb of the negative electrode tab 222c of the negative electrode plate 22 of the electrode body 20 in the power storage element according to the modified example 1. The radius of curvature of the radius of radius of the radius of radius of the radius of radius of the radius of radius of the first rounded portion 21cba and 21cbb of the positive electrode tab 21c of the positive electrode plate 21 is made equal to that of radius of curvature of the radius of curvature of the first rounded portion 21cba and 21cbb. FIG. 8 is a cross-sectional side view showing a cross section of the electrode body 20 of the power storage element of the modification 2 of the power storage element 100 according to the embodiment in the same manner as in FIG.

Referring to FIG. 8, the positive electrode tab 21c of the positive electrode plate 21 of the electrode body 20 in the second modification has the same configuration as the positive electrode tab 21c of the positive electrode plate 21 of the electrode body 20 in the embodiment and the first modification. doing. The negative electrode tab 322c of the negative electrode plate 22 of the electrode body 20 in the modified example 2 has a main body portion 322ca and a second rounded portion 322 cba and 322 cbb, similarly to the negative electrode tab 222c of the electrode body 20 in the modified example 1. ing. The configuration of the main body portion 322ca having a rectangular planar shape is formed to be narrower in the direction along the second edge 22a of the negative electrode plate 22 than the main body portion 222ca of the negative electrode tab 222c in the first modification. , It is different from the main body 222ca.

The radius of curvature of the radius of curvature of the second rounded portions 322cba and 322cbb of the negative electrode tab 322c is the same as that of the first rounded portions 21cba and 21cbb of the positive electrode tab 21c of the positive electrode plate 21, and the second rounded portion of the negative electrode tab 222c in the first modification 1 It is larger than the portions 22cba and 22cbb. The widths B2b3 and B2c3 of the second rounded portions 322cba and 322cbb in the direction along the second edge 22a are equivalent to the widths B1b and B1c of the first rounded portions 21cba and 21cbb of the positive electrode tab 21c, respectively. Further, the maximum width B2 of the negative electrode tab 322c in the direction along the second edge 22a is the maximum width B1d following protrusion from the second edge 22a of the positive electrode tab 2 1 c. Therefore, the width B2a3 of the main body portion 322ca of the negative electrode tab 322c in the direction along the second edge 22a can be smaller than the width B2a2 of the main body portion 222ca of the negative electrode tab 222c in the first modification.

The width B2a3 of the main body portion 322ca and the widths B2b3 and B2c3 of the second rounded portions 322cba and 322cbb satisfy the relationship of B2a3 + B2b3 + B2c3 ≦ B1d (= B1a). By keeping the maximum width B2 of the negative electrode tab 322c small as described above, the region that the negative electrode tab bundle 22d can occupy in the direction along the second edge 22a is kept small. Further, since the other configurations of the power storage element according to the modified example 2 are the same as those of the power storage element according to the modified example 1, the description thereof will be omitted. Further, according to the power storage element according to the modified example 2, the same effect as that of the power storage element according to the modified example 1 can be obtained.

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

The power storage element according to the embodiment and the modified example is a power storage element including an electrode body 20 in which the winding shaft A is arranged so as to be substantially perpendicular to the lid 12 of the container 10, but the winding shaft A is used. It may be a power storage element including an electrode body arranged so as to be oriented along the lid body 12.

In the power storage element according to the embodiment and the modified example, one positive electrode tab bundle 21d and one negative electrode tab bundle 22d are arranged at the end portion 20a of the electrode body 20, but the present invention is not limited to this. Two or more positive electrode tab bundles may be arranged at the end portion 20a of the electrode body 20, or two or more negative electrode tab bundles may be arranged. Positive electrode tab bundles and / or negative electrode tab bundles may be arranged at the ends 20a and 20b of the electrode body 20. In this case, the positive electrode tab bundle may be arranged only on one or both of the ends 20a and 20b of the electrode body 20, and the negative electrode tab bundle may be arranged only on or both of the ends 20a and 20b of the electrode body 20. May be placed in. Even in the above configuration, it is possible to reduce the area that can be occupied by the positive electrode tab bundle and the negative electrode tab bundle.

In the power storage element according to the embodiment and the modified example, the electrode body 20 is a winding type electrode body formed by winding a stacked positive electrode plate, a negative electrode plate and a separator, but the present invention is limited to this. Not a thing. The electrode body may be a stack type electrode body formed by stacking a large number of positive electrode plates, negative electrode plates and separators, and one set or two or more sets of stacked positive electrode plates, negative electrode plates and separators. It may be a Z-shaped electrode body formed by bending a plurality of times.

The power storage element according to the embodiment and the modified example includes one electrode body 20, but may include two or more electrode bodies.

A form constructed by arbitrarily combining embodiments and modifications is also included within the scope of the present invention. Further, the present invention can be realized not only as a power storage element as described above, but also in a power storage device including one or more power storage elements. For example, the present invention can be realized as a power storage device including a plurality of power storage elements. The power storage device includes a plurality of power storage units arranged side by side, and each power storage unit is composed of, for example, a plurality of power storage elements arranged in a row and electrically connected to each other. With the above configuration, a plurality of power storage elements are used as one unit, and the quantity and arrangement of the power storage units can be selected according to the electric capacity required for the power storage device, the shape and dimensions of the power storage device, and the like. A power storage device provided with a plurality of power storage elements and having a high output can also be mounted as a power source for automobiles such as an electric vehicle (EV), a hybrid vehicle (HEV), and a plug-in hybrid vehicle (PHEV). Further, the power storage device provided with a plurality of power storage elements 100 and having a high output may be used as a power source for an electric mobile body such as an automatic guided vehicle (AGV) or a train as well as an automobile.

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

10 container 12 lid (wall)
20 Electrode body 21 Positive electrode plate 21a First edge 21c Positive electrode tab 21caa, 22caa Base end 21cba, 21cbb First rounded part 21d Positive electrode tab bundle 22 Negative electrode plate 22a Second edge 22c, 222c, 322c Negative electrode tab 22cba, 22cbb 2nd rounded part 22d Negative electrode tab bundle 70 Gas discharge valve 100 Power storage element A Winding shaft

Claims (10)

An electrode body including a laminated positive electrode plate and a negative electrode plate is provided.
The positive electrode plate includes a positive electrode tab protruding in the first direction from the linear first edge of the positive electrode plate.
The negative electrode plate includes a negative electrode tab protruding in the first direction from the linear second edge of the negative electrode plate.
The second edge is positioned so as to project in the first direction from the first edge.
The positive electrode tab has a first rounded portion with a radius at the base end.
The negative electrode tab has a second rounded portion having a radius of curvature smaller than that of the first rounded portion at the base end.
The maximum width of the negative electrode tab in the second direction orthogonal to the first direction is equal to or less than the maximum width in the second direction at the protruding portion of the positive electrode tab protruding from the second edge. An electrode body including a laminated positive electrode plate and a negative electrode plate is provided.
The positive electrode plate includes a positive electrode tab protruding in the first direction from the linear first edge of the positive electrode plate.
The negative electrode plate includes a negative electrode tab protruding in the first direction from the linear second edge of the negative electrode plate.
The second edge is positioned so as to project in the first direction from the first edge.
The positive electrode tab has a first rounded portion with a radius at the base end.
The negative electrode tab has a second rounded portion having a radius of curvature smaller than that of the first rounded portion at the base end.
The width of the negative electrode tab on the tip side of the second rounded portion in the second direction orthogonal to the first direction is the width of the positive electrode tab on the tip side of the first rounded portion in the second direction. Smaller storage element. An electrode body including a laminated positive electrode plate and a negative electrode plate is provided.
The positive electrode plate includes a positive electrode tab protruding in the first direction from the linear first edge of the positive electrode plate.
The negative electrode plate includes a negative electrode tab protruding in the first direction from the linear second edge of the negative electrode plate.
The second edge is positioned so as to project in the first direction from the first edge.
The positive electrode tab has a first rounded portion with a radius at the base end.
The negative electrode tab has a second rounded portion with a radius at the base end.
The second way width direction perpendicular to the first direction in the negative electrode tab of the second Raundeddo frontward of the unit, the second direction in the protruding portion of the positive electrode tab protrudes from said second edge A power storage element smaller than the width of. The width of the negative electrode tab on the tip side of the second rounded portion in the second direction orthogonal to the first direction is the width of the positive electrode tab on the tip side of the first rounded portion in the second direction. The power storage element according to claim 3, which is smaller than the above. The positive electrode plate and the negative electrode plate are wound around.
The power storage element according to any one of claims 1 to 4, wherein the winding shaft of the electrode body is along the first direction. The positive electrode plate and the negative electrode plate are wound around.
A plurality of the positive electrode tabs are arranged at intervals in the second direction, and are arranged side by side along the stacking direction to form a positive electrode tab bundle.
A plurality of the negative electrode tabs are arranged at intervals in the second direction, and are arranged side by side along the stacking direction to form a negative electrode tab bundle.
The power storage element according to any one of claims 1 to 5, wherein the positive electrode tab bundle and the negative electrode tab bundle are located apart from each other in the second direction. The sixth aspect of claim 6, wherein at least one of each of the plurality of positive electrode tabs constituting the positive electrode tab bundle and each of the plurality of negative electrode tabs constituting the negative electrode tab bundle are located offset in the second direction. Power storage element. With more containers
The power storage element according to claim 6 or 7, wherein the electrode body is housed in the container with the positive electrode tab bundle and the negative electrode tab bundle folded. A container and a gas discharge valve provided on the wall portion of the container facing the positive electrode tab and the negative electrode tab are further provided.
The power storage element according to any one of claims 1 to 8, wherein the gas discharge valve is located closer to the positive electrode tab than the negative electrode tab in the second direction. The power storage element according to claim 9, wherein the positive electrode tab and the negative electrode tab are arranged at positions that do not overlap with the gas discharge valve when viewed from the wall portion toward the positive electrode tab and the negative electrode tab.

Images