JP2018133306A - Power storage element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a power storage element that broadens the tolerance of lamination precision of a negative electrode tab of a negative electrode plate.SOLUTION: There is disclosed a power storage element 100 which is equipped with an electrode body 20 including a positive electrode plate 21 and a negative electrode plate 22, which are laminated with each other. The positive electrode plate 21 includes a positive electrode tab 21c which protrudes in a first direction from a linear first edge 21a of the positive electrode plate 21, and the negative electrode plate 22 includes a negative electrode tab 22c which protrudes in the first direction from a linear second edge 22a of the negative electrode plate 22. The second edge 22a is located more protruding in the first direction than the first edge 21a. The positive electrode tab 21c has, at the base end 21caa, first rounded parts 21cba and 21cbb to which the radius is attached. The negative electrode tab 22c has, at the base end 22caa, second rounded parts 22cba and 22cbb with the radius attached thereto, of which curvature radius is smaller than that of the first rounded parts 21cba and 21cbb.SELECTED DRAWING: Figure 6

Description

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

  In a power storage element such as a lithium ion secondary battery, for example, a positive electrode and a negative electrode are electrically insulated from each other as in a non-aqueous electrolyte secondary battery as a lithium ion secondary battery described in Patent Document 1. There is one having an electrode body formed by laminating through a separator having a property. The positive electrode of the electrode laminated body as an electrode body described in Patent Document 1 has a positive electrode part 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 bonded to the peripheral edge of the positive electrode portion at a curved portion and is formed integrally with the positive electrode current collector. The negative electrode has a negative electrode part in which a negative electrode active material layer is formed on a negative electrode current collector as a base material, and a negative electrode tab. The negative electrode tab is bonded to the periphery of the negative electrode portion at a curved portion and is formed integrally with the negative electrode current collector. Furthermore, the projection part which projected the positive electrode part perpendicularly | vertically to the negative electrode part exists inside the external shape of a 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 at the periphery of the positive electrode portion, and is perpendicular to the stacking direction of the positive electrode and the negative electrode. It is located inside the electrode laminate from the periphery of the part. The curved portion formed at the base end of the negative electrode tab is located on the periphery of the negative electrode portion, and is located on the outer side of the electrode laminate in the direction perpendicular to the stacking direction than the periphery of the negative electrode portion. For this reason, the width | variety of the negative electrode tab in the direction in alignment with the periphery of a negative electrode part becomes larger than the width | variety of the positive electrode tab in the direction in alignment with the said periphery at the outer side of an electrode laminated body rather than the periphery of a negative electrode part. Further, when the positive electrode and the negative electrode are stacked, the positive electrode tabs are aligned in a line in the stacking direction to form a bundle, and the negative electrode tabs are aligned in a line in the stacking direction to form a bundle. In any case, the bundle of the positive electrode tab and the negative electrode tab may be arranged so as to be shifted from the target position in the direction along the periphery of the negative electrode part. 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 tolerance of the accuracy of lamination of negative electrode tabs having a larger width outside the peripheral edge of the negative electrode part The degree is narrow and the manufacturing cost increases.

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

  In order to achieve the above object, a power storage device according to one embodiment of the present invention includes an electrode body including a stacked positive electrode plate and a negative electrode plate, and the positive electrode plate extends from a linear first edge of the positive electrode plate. The negative electrode plate includes a negative electrode tab protruding in the first direction from a linear second edge of the negative electrode plate, and the second edge is formed from the first edge. The positive electrode tab has a first rounded portion that is rounded at the base end, and the negative electrode tab is at the base end from the first rounded portion. Also has a second rounded portion which is rounded with a small radius of curvature.

  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.

  The power storage device according to one embodiment of the present invention includes an electrode body including a stacked positive electrode plate and negative electrode plate, and the positive electrode plate projects in a first direction from a 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 a first direction from a linear second edge of the positive electrode plate, and the second edge is more in the first direction than the first edge. The positive electrode tab has a first rounded portion with a rounded end at the base end, and the negative electrode tab has a second rounded portion with a rounded end at the base end. And the width | variety of the said negative electrode tab of the 2nd direction orthogonal to said 1st direction is below the width | variety of the said 2nd direction in the protrusion part of the said positive electrode tab which protrudes rather than the said 2nd edge.

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

  The positive electrode plate and the negative electrode plate may be wound, and a 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 are arranged side by side in 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 direction of lamination to form a negative electrode tab bundle, and the positive electrode tab bundle and the negative electrode tab The bundle 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 shifted in the second direction.

  The power storage element may further include a container, and the electrode body may be accommodated in the container in a state where the positive electrode tab bundle and the negative electrode tab bundle are bent.

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

  The positive electrode tab and the negative electrode tab may be disposed at a position where the positive electrode tab and the negative electrode tab 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 electricity storage device of the present invention, it becomes possible to widen the tolerance of the lamination accuracy of the negative electrode tab of the negative electrode plate.

It is a perspective view which shows typically the external appearance of the electrical storage element which concerns on embodiment of this invention. It is a disassembled perspective view of the electrical storage element of FIG. It is a disassembled perspective view of the cover body of FIG. 2, and its peripheral component. It is a perspective view of the electrode body which expands and shows a part of electrode body of Drawing 2. FIG. 2 is a cross-sectional view of a power storage element viewed from a direction V along a lid body of the power storage element of FIG. FIG. 6 is a cross-sectional side view of a cross section of the electrode body along a direction perpendicular to a stacking direction of the positive electrode plate and the negative electrode plate of the electrode body of FIG. It is a cross-sectional side view which shows the cross section of the electrode body of the electrical storage element of the modification 1 of the electrical storage element which concerns on embodiment similarly to FIG. It is a cross-sectional side view which shows the cross section of the electrode body of the electrical storage element of the modification 2 of the electrical storage element which concerns on embodiment similarly to FIG.

  Hereinafter, a power storage device according to an embodiment of the present invention will be described with reference to the drawings. It should be noted that each of the embodiments described below shows a comprehensive or specific example. Numerical values, shapes, materials, constituent elements, arrangement positions and connection forms of the constituent elements, steps (processes), order of steps, and the like shown in the following embodiments are merely examples, and are not intended to limit the present invention. In addition, among the constituent elements in the following embodiments, constituent elements that are not described in the independent claims indicating the highest concept are described as optional constituent elements. Each figure in the accompanying drawings is a schematic diagram and is not necessarily illustrated strictly. Furthermore, in each figure, the same code | symbol is attached | subjected about the same or similar component. In the following description of the embodiments, expressions with “substantially” such as substantially parallel and substantially orthogonal may be used. For example, “substantially parallel” not only means completely parallel, but also means substantially parallel, that is, including a difference of, for example, several percent. The same applies to expressions involving other “abbreviations”.

[Embodiment]
The structure of the electrical storage element 100 which concerns on embodiment is demonstrated. FIG. 1 is a perspective view schematically showing an external appearance of a power storage device 100 according to the embodiment. As shown in FIG. 1, the power storage element 100 has a flat rectangular parallelepiped outer shape. The storage element 100 is a chargeable / dischargeable secondary battery. For example, the electrical storage element 100 is a nonaqueous electrolyte secondary battery such as a lithium ion secondary battery. However, the storage element 100 is not limited to a non-aqueous electrolyte secondary battery, and may be a secondary battery other than the non-aqueous electrolyte secondary battery, and can store the stored electricity without being charged by the user. A usable primary battery or a capacitor may be used. Further, the outer shape of the power storage element 100 is not limited to a rectangular parallelepiped shape, and may be a shape including a curved portion such as a columnar shape or a long columnar shape.

  Referring to FIGS. 1 and 2, the electric storage element 100 includes a flat rectangular parallelepiped container 10, an electrode body 20 included in the container 10, a positive electrode terminal 30, and a negative electrode terminal 40. 2 is an exploded perspective view of the storage element 100 of FIG. The container 10 has a bottomed rectangular tube-shaped container body 11 and an elongated rectangular plate-like lid body 12 that can close the elongated rectangular opening 11 a of the container body 11. The container body 11 has a flat rectangular parallelepiped outer shape. The container body 11 and the lid body 12 are fixed with their joints in an airtight state by a joining method such as welding. Although it does not limit, the container main body 11 and the cover body 12 may be produced from weldable metals, such as aluminum, aluminum alloy, stainless steel, for example. Here, the lid 12 is an example of a wall of a container.

  An electrolyte such as an electrolytic solution (in this embodiment, a nonaqueous electrolytic solution) is enclosed 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, there is no particular limitation on the type thereof as long as it does not impair the performance of the electricity storage device 100, and various types can be selected.

  On the outer surface 12 a of the lid body 12, the positive terminal 30 and the negative terminal 40 are disposed. The positive electrode terminal 30 and the negative electrode terminal 40 having conductivity pass through the lid body 12 and protrude from the inner surface 12b opposite to the outer surface 12a of the lid body 12, and on the opposite side, the positive electrode lead plate having conductivity. 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 accommodated 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. Moreover, in order to electrically insulate between the electrode body 20 and the container main body 11, the electrode body 20 may be covered with an insulating film etc. A buffer 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 12 a of the lid 12. The gas discharge valve 70 is disposed between the positive electrode terminal 30 and the negative electrode terminal 40, and is 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 to discharge the gas to the outside of the container 10. In the present embodiment, the gas discharge valve 70 has a configuration formed integrally 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 weakening 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 planar shape at a position facing each other. In addition, a planar shape is a shape when the weakening part 71 is seen in the direction perpendicular | vertical to the outer surface 12a and the inner surface 12b. When a predetermined pressure is applied to the gas discharge valve 70 due to an increase in the pressure in the container 10 or the like, the weakened portion 71 is broken to form an opening as a pressure relief hole. Furthermore, the weakening part 71 may be comprised easily in the part of the groove part 72 by the groove part 72 being cut. The groove 72 has a shape in which two grooves intersect in the present embodiment, but has a shape in which a plurality of grooves intersect. The weakened portion 71 tends to break at the intersection of the grooves. The pressure at which the gas discharge valve 70 is opened 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, the depth of the groove, 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. FIG. 3 is an exploded perspective view of the lid 12 of FIG. 2 and its surrounding components. The positive electrode lead plate 51 constitutes a part of the constituent elements of the positive electrode current collector 50, and the negative electrode lead plate 61 constitutes a part of the constituent elements of the negative electrode current collector 60. The positive electrode current collector 50 is a plate-like 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 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-like 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 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-like upper insulating member 31 is provided between the positive electrode terminal 30 and the lid body 12 to electrically insulate them from each other, and a plate-like lower insulating member 32 serves as the lid body 12 and the positive electrode current collector. It is provided between the body 50 and electrically insulates them from each other. A plate-like upper insulating member 41 is provided between the negative electrode terminal 40 and the lid body 12 to electrically insulate them from each other, and a plate-like lower insulating member 42 serves as the lid body 12 and the negative electrode current collector 60. And electrically insulate them from each other. Each of the upper insulating members 31 and 41 and the lower insulating members 32 and 42 is formed of a material having electrical insulation properties such as resin, for example, PPS (polyphenylene sulfide), PEEK (polyether ether ketone), PP (Polypropylene), PFA (tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer) and the like.

  The positive terminal 30 and the negative terminal 40 have plate-like terminal bodies 30a and 40a and cylindrical shaft portions 30b and 40b extending from the terminal bodies 30a and 40a, respectively. The shaft portion 30 b of the positive electrode terminal 30 extends through the upper insulating member 31, the lid body 12, the lower insulating member 32, and the positive electrode current collector 50. The shaft portion 40 b of the negative electrode terminal 40 extends through the upper insulating member 41, the lid body 12, the lower insulating member 42, and the negative electrode current collector 60. In the present embodiment, the shaft portions 30b and 40b are plastically deformed, that is, caulked, so that the tips protruding from the positive electrode current collector 50 and the negative electrode current collector 60 are pressed to expand in diameter. Thus, the positive electrode current collector 50 and the negative electrode current collector 60 are connected. Thereby, 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 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 joined by caulking of the shaft portions 30b and 40b. It is not limited. The connection structure is a structure in which the terminal body 30a or 40a and the positive electrode current collector 50 or the negative electrode current collector 60 are connected while the upper insulating member 31 or 41, the lid 12 and the lower insulating member 32 or 42 are sandwiched. If it is. For example, a bolt and a nut 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 formed integrally, and the negative electrode terminal 40 and the negative electrode current collector 60 may be formed integrally. In this case, the upper insulating member 31 and the lower insulating member 32 may be integrally formed with the lid body 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 formed with the lid 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 into a U shape. The positive electrode lead plate 51 and the negative electrode lead plate 61 are made of the same material as the positive electrode current collector 50 and the negative electrode current collector 60, respectively. Note that the shapes of the positive electrode lead plate 51 and the negative electrode lead plate 61 are not limited to the U-shape. As described below, the connection between the positive electrode current collector 50 and the electrode body 20 and the negative electrode current collector Any structure that relays the connection between the body 60 and the electrode body 20 may be used.

  The flat connection part 51a and the connection part 51b which form two U-shaped opposing side parts in 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. The flat connection part 61a and the connection part 61b that form two opposing sides of the U-shape in 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 and resistance welding can be used. For the connection between the connection part 51b and the electrode body 20, and the connection between the connection part 61b and the electrode body 20, welding by ultrasonic welding, resistance welding or the like, or joining by plastic deformation such as joining by caulking can be used. The positive electrode current collector 50, the negative electrode current collector 60, and the electrode body 20 may be connected using the connection method described above without providing the positive electrode lead plate 51 and the negative electrode lead plate 61.

  With reference to FIG.2 and FIG.4, the structure of the electrode body 20 is demonstrated. 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. The electrode body 20 is a power storage element (also called a power generation element) that can store electricity. The electrode body 20 includes a sheet-like positive electrode plate 21 having a long rectangular belt-like planar shape, a sheet-like negative electrode plate 22 having a long rectangular belt-like planar shape, and a long rectangular belt-like planar shape. The two sheet-like separators 23 are included so as to be layered.

  In the electrode body 20, one separator 23, the negative electrode plate 22, the other separator 23, and the positive electrode plate 21 are layered in this order, and the winding axis B is in a winding direction B as shown in FIG. It is formed by being wound together in multiple spirals. The winding axis A is a virtual axis indicated by a one-dot chain line in FIGS. 2 and 4, and the electrode body 20 has a substantially symmetric configuration with respect to the winding axis A. Although not limited, in the present embodiment, the electrode body 20 has a flat outer shape having an oblong shape with 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 other polygons.

  The positive electrode plate 21 is formed by a method such as coating on a positive electrode base material that is a long rectangular belt-shaped metal foil made of a metal such as aluminum or an aluminum alloy, and on the entire wide main surface on both sides of the positive electrode base material. And a formed positive electrode active material layer (indicated by hatching in FIG. 4). The negative electrode plate 22 is formed by a method such as coating on a negative electrode base material that is a long rectangular strip-shaped metal foil made of a metal such as copper or a copper alloy, and on the entire wide main surface on both sides of the negative electrode base material. And the formed negative electrode active material layer (indicated by hatching in FIG. 4). As the positive electrode active material used for the positive electrode active material layer or the negative electrode active material layer, any known material can be used as long as it is a positive electrode active material or negative electrode active material capable of occluding and releasing lithium ions. 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 substrate and the negative electrode substrate, respectively, but are formed only on one main surface. Also good. The separator 23 is a microporous sheet made of a material having electrical insulation properties such as a resin.

  On one first edge 21a of two linear edges 21a and 21b along the longitudinal direction and the winding direction B in the positive electrode plate 21, a plurality of rectangular foil-shaped positive electrode tabs 21c are provided as the first direction. It protrudes in a direction substantially perpendicular to the first edge 21a. The some positive electrode tab 21c is arrange | positioned at intervals along the 1st edge 21a. The positive electrode tab 21c extends continuously and integrally from the positive electrode base material, and constitutes 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 no positive electrode active material layer is formed on the positive electrode tab 21c. In the present embodiment, one positive electrode tab 21 c is disposed per 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 positioned 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 positioned in a line in the stacking direction of multiple layers formed by the wound positive electrode plate 21, negative electrode plate 22, and 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 process of winding the electrode body 20.

  A plurality of rectangular foil-like negative electrode tabs 22c are provided as the first direction on one second edge 22a of the two linear edges 22a and 22b along the longitudinal direction and the winding direction B of the negative electrode plate 22. It protrudes in a direction substantially perpendicular to the second edge 22a. The plurality of negative electrode tabs 22c are arranged at intervals along the second edge 22a. The negative electrode tab 22c continuously and integrally extends from the negative electrode base material, and constitutes 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 22 c is disposed per turn of the negative electrode plate 22 in the electrode body 20. In the electrode body 20 after winding, the plurality of negative electrode tabs 22c are gathered and positioned at one place to form a negative electrode tab bundle 22d. In the negative electrode tab bundle 22 d, the plurality of negative electrode tabs 22 c are positioned in a line in the stacking direction of the wound positive electrode plate 21, negative electrode plate 22, and separator 23. 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, the direction along the second edge 22a in the process of winding the electrode body 20. The negative electrode tab bundle 22d is disposed away from the positive electrode tab bundle 21d along the second edge 22a.

  The number of the positive electrode tabs 21c and the negative electrode tabs 22c arranged for each turn of the positive electrode plate 21 and the negative electrode plate 22 is not limited to one. The number of the positive electrode tab bundle 21d and the negative electrode tab bundle 22d is 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 21 c and the negative electrode tab 22 c 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 adjacent to each other and substantially parallel, 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 Located approximately parallel.

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

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

  Furthermore, 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-like body is positioned so as to be opposed to each other with the winding axis A sandwiched between the two flat portions 20c and 20d that are wide and flat, and is opposed to each other with the winding axis A interposed therebetween and is curved in a semicircular shape. The two curved portions 20e and 20f are configured. The flat portions 20c and 20d extend substantially parallel to each other. The curved portions 20e and 20f respectively connect the flat portion 20c and the flat portion 20d at both ends. The electrode body 20 has the end portion 20a, the positive electrode tab bundle 21d and the negative electrode tab bundle 22d opposed to the lid body 12, and the flat portions 20c and 20d and the curved portions 20e and 20f opposed to the side wall of the container body 11, Housed inside. That is, the electrode body 20 is accommodated in the container 10 with the winding axis A in a direction substantially perpendicular to the lid body 12. Moreover, in this Embodiment, although the positive electrode tab bundle 21d and the negative electrode tab bundle 22d are arrange | positioned at the flat part 20d, it is not limited to this.

  Furthermore, the positive electrode tab bundle 21d of the wound electrode body 20 is connected to the connection portion 51b of the positive electrode lead plate 51 shown in FIG. 3 in a state where the positive electrode tab bundle 21d is bent in the direction from the flat portion 20d toward the flat portion 20c. The negative electrode tab bundle 22d is connected to the connection portion 61b of the negative electrode lead plate 61 shown in FIG. 3 in a state of being bent in a direction from the flat portion 20d toward the flat portion 20c. Thereby, 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 through the negative electrode current collector 60 and the negative electrode lead plate 61. The U-shaped lead plates 51 and 61 are stretched 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. And may be bent into a U shape after the connection is completed.

  2, 3, and 5, the gas discharge valve 70 formed on the lid 12 has a positive tab bundle when viewed in the direction from the lid 12 toward the container body 11, that is, in the winding axis A direction. 21d and the negative electrode tab bundle 22d are arranged so as not to overlap. Further, the gas exhaust valve 70 is disposed 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. 5 is a cross-sectional view of the electric storage element 100 as viewed from the direction V along the lid 12 of the electric storage element 100 of FIG. 1 and passing through the vicinity of the end 20a of the electrode body 20 in the winding axis A direction. . The direction from the lid 12 toward the container body 11 is also the direction from the lid 12 toward the positive electrode tab bundle 21d and the negative electrode tab bundle 22d.

  The gas discharge valve 70 is positioned 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 toward the positive electrode terminal 30. Accordingly, the gas discharge valve 70 is positioned closer to the positive electrode current collector 50 and the positive electrode lead plate 51 than 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 above-described positional relationship with the gas discharge valve 70 are arranged with their positions shifted in the winding direction B of the electrode body 20, that is, the direction along the flat portion 20d. Even in such a case, it is possible to prevent the gas exhaust valve 70 from being located at a position overlapping the gas exhaust valve 70.

  With reference to FIG. 6, the detailed structure of the positive electrode tab 21c and the negative electrode tab 22c is demonstrated. 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. FIG. 6 is a cross-sectional side view of the body 20 as viewed from the flat part 20d toward the flat part 20c. In FIG. 6, the separator 23 is omitted.

  The positive electrode tab 21c integrally includes a main body portion 21ca and first rounded portions 21cba and 21cbb that cut corner portions of both side portions of the main body portion 21ca with rounded corners. The main body portion 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 on the first edge 21a side of the main body portion 21ca, at both ends. The base end 21caa is also a base 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 protruding direction of the main body portion 21ca and the first edge 21a, respectively. In the present embodiment, the side portions 21cab and 21cac extend substantially parallel to each other, but are not limited thereto.

  The first rounded portions 21cba and 21cbb are portions that are located at the corners of the side portions 21cab and 21cac and the first edge 21a, respectively, and are cornered in a concave curved shape in the recess direction of the corners. The first rounded portions 21cba and 21cbb form the edge of the positive electrode tab 21c having a rounded curved shape. In the present embodiment, the first rounded portions 21cba and 21cbb form an arc-shaped edge of the positive electrode tab 21c, that is, an edge with a rounded shape. The edges formed by the first rounded portions 21cba and 21cbb extend smoothly and continuously from the side portions 21cab and 21cac, and extend smoothly and continuously from the first edge 21a. The first rounded portions 21cba and 21cbb may form an edge that is curved with an equivalent radius, that is, a radius of curvature, or an edge that is curved with a different radius. The first rounded portions 21cba and 21cbb may have similar shapes and dimensions, or may have different shapes and dimensions. Further, the distal end 21 cad of the main body 21 ca and the corners of the side portions 21 cab and 21 cac at positions facing the base end 21 caa are chamfered in a curved shape that is convex in the protruding direction of the corner.

  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 It is located between the second edge 22 a of the plate 22 and the first edge 21 a of the positive electrode plate 21. That is, the first rounded portions 21cba and 21cbb do not protrude beyond 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 is the width B1a at the base end 21caa of the main body 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 proximal end 21caa to the distal end 21cad. Further, the protruding portion of the positive electrode tab 21c protruding from the second edge 22a of the negative electrode plate 22 in the winding axis A direction is formed by a protruding portion 21cae that is a part of the main body portion 21ca. The maximum width B1d in the direction along the first edge 21a in the protruding portion of the positive electrode tab 21c 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 base portions of both side portions of the main body portion 22ca with rounded corners. The main body 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 22caa is also a base portion of the main body portion 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 protruding direction of the main body portion 22ca and the second edge 22a, respectively. In the present embodiment, the side portions 22cab and 22cac extend substantially parallel to each other, but are not limited thereto.

  The second rounded portions 22cba and 22cbb are portions located at the corners of the side portions 22cab and 22cac and the second edge 22a, respectively, and are corners that are concavely curved in the recess 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 arc-shaped edge of the negative electrode tab 22c, that is, an edge with a rounded shape. The edges formed by the second rounded portions 22cba and 22cbb extend smoothly and continuously from the side portions 22cab and 22cac, and extend smoothly and continuously from the second edge 22a. The second rounded portions 22cba and 22cbb may form an edge that is curved with an equivalent radius, or may form an edge that is curved with a different radius. The second rounded portions 22cba and 22cbb may have similar shapes and dimensions, or may have different shapes and dimensions. Further, the front end 22cad of the main body portion 22ca located at the position facing the base end 22caa and the corner portions of the side portions 22cab and 22cac are chamfered in a curved shape that is convex in the protruding direction of the corner portions.

  The negative electrode tab 22c has a maximum width B2 as a width in a direction along the second edge 22a. The maximum width B2 includes a width B2a at the base end 22caa of the main body 22ca in the direction along the second edge 22a, and 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 proximal end 22caa to the distal end 22cad.

  In the present embodiment, the width B2a of the main body portion 22ca of the negative electrode tab 22c is equal to the width B1a of the main body portion 21ca of the positive electrode tab 21c. The curvature radii 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. For this reason, the widths B2b and B2c of the second rounded portions 22cba and 22cbb are both 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, than when formed in the same shape and size as the positive electrode tab 21c. Can be suppressed. Accordingly, even when the positions of the plurality of negative electrode tabs 22c are shifted from each other in the direction along the second edge 22a, that is, in the winding direction, the region occupied by the negative electrode tab bundle 22d in the direction along the second edge 22a can be kept small. .

  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 the width B1a of the main body portion 21ca. Therefore, even when the positions of the plurality of positive electrode tabs 21c are shifted 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 is suppressed to be small.

  Further, the maximum width B2 of the negative electrode tab 22c on the end portion 20a of the electrode body 20 is larger than the maximum width B1d of the portion protruding from the end portion 20a of the electrode body 20 in the positive electrode tab 21c, that is, the width B1a. However, as shown in FIG. 5, the negative electrode tab bundle 22d is in the direction along the second edge 22a of the negative electrode plate 22 in the flat portion 20d, that is, the arrangement of the positive electrode tab bundle 21d, the gas exhaust valve 70, and the negative electrode tab bundle 22d. In the direction, it is located at a position farther from the gas discharge valve 70 than the positive electrode tab bundle 21d. 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, that is, the direction along the second edge 22a in 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 to the positive electrode terminal 30 is larger than the positive electrode tab bundle 21d. Thereby, the tolerance | permissible_value of the position shift from the preset arrangement position with respect to the some negative electrode tab 22c is larger than the some positive electrode tab 21c. Therefore, it is 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 axis A direction, the operation of the gas discharge valve 70 may be adversely affected.

  As described above, power storage device 100 according to the present embodiment includes electrode body 20 including positive electrode plate 21 and negative electrode plate 22 that are stacked. The positive electrode plate 21 includes a positive electrode tab 21c that protrudes in the first direction from the linear first edge 21a of the positive electrode plate 21, and the negative electrode plate 22 extends from the linear second edge 22a of the negative electrode plate 22 in the first direction. A protruding negative electrode tab 22c is included. The second edge 22a is positioned so as to protrude in the first direction from the first edge 21a. The positive electrode tab 21c has first rounded portions 21cba and 21cbb that are rounded at the base end 21caa, and the negative electrode tab 22c has a curvature smaller than the first rounded portions 21cba and 21cbb at the base end 22caa. It has the 2nd rounded part 22cba and 22cbb to which the radius of the radius is attached.

  In the above-described configuration, the maximum width of the negative electrode tab 22c along the second edge 22a can be reduced by reducing the radius of curvature of the radius of the second rounded portions 22cba and 22cbb of the negative electrode tab 22c. In addition, 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. For this reason, the width | variety of the part which protrudes from the 2nd edge 22a in the positive electrode tab 21c is suppressed small. Therefore, the width of the portion protruding from the second edge 22a in the positive electrode tab 21c and the negative electrode tab 22c is suppressed to be small. As a result, even when the positions of the positive electrode tab 21c and the negative electrode tab 22c are shifted from the predetermined arrangement position in the direction along the second edge 22a, the positive electrode tab 21c and the negative electrode tab 22c protrude from the second edge 22a. The area that can be occupied by the area is kept small. Therefore, the tolerance of the stacking accuracy of the positive electrode plate 21 and the negative electrode plate 22 is widened with respect to the positional deviation between the positive electrode tab 21c and the negative electrode tab 22c.

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

  In the electrode body 20 of the energy storage device 100 according to the embodiment, the positive electrode plate 21 and the negative electrode plate 22 are wound, and the winding axis A of the electrode body 20 is a positive electrode tab from the first edge 21 a of the positive electrode plate 21. Along the first direction which is the protruding direction of 21c. In the above-described 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 during winding, and the thicknesses 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 in accordance with the variation of the difference. In the electrode body 20 as described above, in order to prevent an area where the positive electrode tab 21c and the negative electrode tab 22c can exist from becoming excessive, the positive electrode tab 21c and the negative electrode tab 22c protrude from the second edge 22a of the negative electrode plate 22. It is particularly effective to keep the width of the portion small.

  In the electrode body 20 of the energy storage device 100 according to the embodiment, the positive electrode plate 21 and the negative electrode plate 22 are wound. The plurality of positive electrode tabs 21c are arranged at intervals in a 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 in 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. Furthermore, the positive electrode tab bundle 21d and the negative electrode tab bundle 22d are located apart in the second direction. In the above-described configuration, the positive electrode tab bundle 21d and the negative electrode tab bundle 22d are arranged along the winding direction by suppressing the width of the portion protruding from the second edge 22a of the negative electrode plate 22 in the positive electrode tab 21c and the negative electrode tab 22c. The area that can be occupied on the body 20 can be reduced.

  In electrode body 20 of power storage device 100 according to the embodiment, at least one of each of a plurality of positive electrode tabs 21c constituting positive electrode tab bundle 21d and each of a plurality of negative electrode tabs 22c constituting negative electrode tab bundle 22d is a positive electrode The plate 21 is shifted from the first edge 21a of the plate 21 in the second direction perpendicular to the protruding direction of the positive electrode tab 21c. In the above-described 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, any of the plurality of positive electrode tabs 21c and the plurality of negative electrode tabs 22c is predetermined in the second direction. Even when the position is shifted from this position, the width along the winding direction in which the positive electrode tab bundle 21d and the negative electrode tab bundle 22d can occupy on the electrode body 20 can be reduced.

  In the electricity storage device 100 according to the embodiment, the electrode body 20 is accommodated 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-described configuration, the positive electrode tab 21c and the negative electrode tab 22c have rounded portions 21cba, 21cbb, 22cba, and 22cbb at 21caa and 22caa at the proximal ends, so even if they are housed in the container 10 in a folded state, Suppresses breakage at 21caa and 22caa.

  The power storage device 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 positioned closer to the positive electrode tab 21 c than the negative electrode tab 22 c in the second direction orthogonal to the protruding direction of the positive electrode tab 21 c from the first edge 21 a of the positive electrode plate 21. In the above-described configuration, the negative electrode tab 22 c that can increase the width of the portion protruding from the second edge 22 a is suppressed from being located at a position that hinders the operation of the gas discharge valve 70.

  In the electricity storage device 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 cover 12 toward the positive electrode tab 21c and the negative electrode tab 22c. . In the above-described configuration, the positive electrode tab 21 c and the negative electrode tab 22 c are suppressed from being located at a position that hinders the operation of the gas discharge valve 70.

  Further, in the electrode body 20 of the energy storage device 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 both the first of the positive electrode tab 21c of the positive electrode plate 21. Although it is smaller than width B1b and B1c of rounded part 21cba and 21cbb, it is not limited to this. The widths B2b and B2c of the second rounded portions 22cba and 22cbb may only be configured to make the maximum width B2 of the negative electrode tab 22c 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 width B1b and / or B1c of the first rounded portions 21cba and 21cbb of the positive electrode tab 21c.

  Further, in the electrode body 20 of the energy storage device 100 according to the embodiment, the first rounded portions 21 cba and 21 cbb of the positive electrode tab 21 c of the positive electrode plate 21 form an arc-shaped edge, and the second negative electrode tab 22 c of the negative electrode plate 22. Although rounded part 22cba and 22cbb formed the arc-shaped edge, it is not limited to this. The rounded portions 21cba, 21cbb, 22cba, and 22cbb may have a configuration in which the corner 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 recess direction of the corner. For example, the shape of the edge formed by the rounded portions 21cba, 21cbb, 22cba, and 22cbb is not an arc having a constant curvature, as in the embodiment, but may be a shape in which arcs having a plurality of curvatures are combined. 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 include a straight line in part. Such rounded portions 21cba, 21cbb, 22cba and 22cbb may only have a configuration of cutting so as to suppress the breakage of the positive electrode plate 21 or the negative electrode plate 22 at the corners of the positive electrode tab 21c or the negative electrode tab 22c. .

[Modification 1]
As Modification 1 of power storage element 100 according to the embodiment, the following configuration is exemplified. Specifically, as shown in FIG. 7, in the electrode body 20 of the energy storage device according to the first modification, the maximum width B2 of the negative electrode tab 222 c of the negative electrode plate 22 is the negative electrode plate 22 of the positive electrode tab 21 c of the positive electrode plate 21. The maximum width B1d of the protruding portion from the second edge 22a is set to be equal to or less than the maximum width B1d. FIG. 7 is a cross-sectional side view showing a cross section of electrode body 20 of the power storage element of Modification Example 1 of power storage element 100 according to the embodiment in the same manner as FIG. 6. In the following description of the modified examples, the constituent elements having the same reference numerals as the reference numerals in the previous drawings are the same or similar constituent elements, and thus detailed description thereof is omitted.

  Referring to FIG. 7, the positive electrode tab 21 c of the positive electrode plate 21 of the electrode body 20 in Modification 1 has the same configuration as the positive electrode tab 21 c of the electrode body 20 in the embodiment. Similarly to the negative electrode tab 22c 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 Modification 1 has a main body portion 222ca and second rounded portions 22cba and 22cbb. Yes. The configuration of the main body portion 222ca having a rectangular planar shape is that the main body portion 22ca is 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 configurations of the second rounded portions 22cba and 22cbb of the negative electrode tab 222c are the same as 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 B2a2 of the main body portion 222ca takes a value such that the maximum width B2 of the negative electrode tab 222c is equal to or less than the maximum width B1d of the protruding portion from the second edge 22a of the negative electrode tab 22c. Therefore, the width B2a2 satisfies the relationship B2a2 + B2b + B2c ≦ B1d (= B1a), that is, the relationship B2a2 ≦ B1a−B2b−B2c.

  By suppressing the maximum width B2 of the negative electrode tab 222c to be small as described above, the region that the negative electrode tab bundle 22d can occupy in the direction along the second edge 22a is suppressed to be small. Further, the reduction of the maximum width B2 of the negative electrode tab 222c is achieved by reducing the widths B2b and B2c of the second rounded portions 22cba and 22cbb from the widths B1b and B1c of the first rounded portions 21cba and 21cbb, and the width of the main body portion 222ca. This 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.

  In addition, since the other configuration of the power storage element according to Modification Example 1 is the same as that of power storage element 100 according to the embodiment, description thereof is omitted. Furthermore, according to the electricity storage device according to the first modification, the same effect as the electricity storage device 100 according to the embodiment can be obtained. Further, in the electrode body 20 of the energy storage device according to Modification 1, 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. 22 is equal to or less than the maximum width B1d in the second direction at the protruding portion of the positive electrode tab 21c protruding from the second edge 22a. In the above-described configuration, the maximum width B2 of the negative electrode tab 222c on the second edge 22a of the negative electrode plate 22 is kept small.

  Further, in the electrode body 20 of the energy storage device according to the first modification, the negative electrode tab 222c on the tip side of the second rounded portions 22cba and 22cbb is in the second direction orthogonal to the protruding direction of the positive electrode tab 21c from the first edge 21a. Width B2a2. The width B2a2 is smaller than the width B1d (= width B1a) in the second direction of the positive electrode tab 21c on the distal end side than 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 second modification of the electricity storage device 100 according to the embodiment, the following configuration can be given. Specifically, as illustrated in FIG. 8, the power storage device according to Modification Example 2 is the same as the power storage device according to Modification Example 1, except that the second rounded portions 22 cba and 22 cbb of the negative electrode tab 222 c of the negative electrode plate 22 of the electrode body 20. The radius of curvature of the round is equal to the radius of curvature of the rounds of the first rounded portions 21cba and 21cbb of the positive electrode tab 21c of the positive electrode plate 21. FIG. 8 is a cross-sectional side view showing a cross section of electrode body 20 of the power storage element of Modification Example 2 of power storage element 100 according to the embodiment in the same manner as FIG. 6.

  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 Modification 2 has a main body portion 322ca and second rounded portions 322cba and 322cbb, similarly to the negative electrode tab 222c of the electrode body 20 in Modification Example 1. ing. The configuration of the main body portion 322ca having a rectangular planar shape is 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 Modification 1. , Different from the main body 222ca.

  The radius of curvature of the radius of the second rounded portions 322cba and 322cbb of the negative electrode tab 322c is equal to 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 Modification 1 It is larger than the parts 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 equal 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 equal to or less than the maximum width B1d of the protruding portion from the second edge 22a of the negative electrode tab 22c. For this reason, 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 Modification 1.

  The width B2a3 of the main body 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 suppressing the maximum width B2 of the negative electrode tab 322c to be small as described above, the region that the negative electrode tab bundle 22d can occupy in the direction along the second edge 22a is suppressed to a small size. In addition, the other configuration of the electricity storage device according to Modification 2 is the same as that of the electricity storage device according to Modification 1, and therefore the description thereof is omitted. Furthermore, according to the electricity storage device according to Modification Example 2, the same effect as the electricity storage device according to Modification Example 1 can be obtained.

[Other variations]
The power storage device according to the embodiment and the modification of the present invention has been described above, but the present invention is not limited to the embodiment and the modification. That is, it should be considered that the embodiment and the modification disclosed this time are examples in all respects and are not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

  The power storage device according to the embodiment and the modification is a power storage device including the electrode body 20 that is arranged with the winding axis A in a direction substantially perpendicular to the lid body 12 of the container 10. An electricity storage element including an electrode body arranged in a direction along the lid body 12 may be used.

  In the electricity storage device according to the embodiment and the modification, one positive electrode tab bundle 21d and one negative electrode tab bundle 22d are arranged at the end 20a of the electrode body 20, but the present invention is not limited to this. Two or more positive electrode tab bundles may be disposed at the end portion 20a of the electrode body 20, or two or more negative electrode tab bundles may be disposed. A positive electrode tab bundle and / or a negative electrode tab bundle may be disposed at the end portions 20 a and 20 b of the electrode body 20. In this case, the positive electrode tab bundle may be disposed only on one or both of the end portions 20a and 20b of the electrode body 20, and the negative electrode tab bundle is disposed only on the other of the end portions 20a and 20b of the electrode body 20 or both. May be arranged. Even in the configuration as described above, it is possible to reduce the area that the positive electrode tab bundle and the negative electrode tab bundle can occupy.

  In the energy storage device according to the embodiment and the modification, the electrode body 20 is a wound electrode body formed by winding the stacked positive electrode plate, negative electrode plate, and separator, but is not limited thereto. Not a thing. The electrode body may be a stack type electrode body formed by stacking a large number of positive plates, negative plates and separators, and a set of two or more stacked positive plates, negative plates and separators. It may be a Z-shaped electrode body formed by bending a plurality of wires.

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

  Forms constructed by arbitrarily combining the embodiments and the modified examples are also included in the scope of the present invention. In addition, 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 includes, for example, a plurality of power storage elements arranged in a line and electrically connected to each other. With the above-described configuration, a plurality of power storage elements are used as one unit, and the quantity and arrangement of 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 that includes a plurality of power storage elements and has high output can be mounted as a power source for vehicles such as an electric vehicle (EV), a hybrid vehicle (HEV), and a plug-in hybrid vehicle (PHEV). Furthermore, a power storage device that includes a plurality of power storage elements 100 and has a high output may be used as a power source for not only an automobile but also an electric mobile body such as an automatic guided vehicle (AGV) or a train.

  The present invention is applicable to power storage elements such as lithium ion secondary batteries.

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 portion 21d positive electrode tab bundle 22 negative electrode plate 22a second edge 22c, 222c, 322c negative electrode tab 22cba, 322cb Second rounded portion 22d Negative electrode tab bundle 70 Gas exhaust valve 100 Power storage element A Winding shaft

Claims (10)

An electrode body including a laminated positive electrode plate and negative electrode plate is provided,
The positive electrode plate includes a positive electrode tab protruding in a first direction from a linear first edge of the positive electrode plate,
The negative electrode plate includes a negative electrode tab protruding in the first direction from a linear second edge of the negative electrode plate,
The second edge is positioned to protrude in the first direction from the first edge,
The positive electrode tab has a first rounded portion that is rounded at a proximal end,
The negative electrode tab has a second rounded portion having a radius of curvature smaller than that of the first rounded portion at a 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. Power storage element. An electrode body including a laminated positive electrode plate and negative electrode plate is provided,
The positive electrode plate includes a positive electrode tab protruding in a first direction from a linear first edge of the positive electrode plate,
The negative electrode plate includes a negative electrode tab protruding in the first direction from a linear second edge of the positive electrode plate,
The second edge is positioned to protrude in the first direction from the first edge,
The positive electrode tab has a first rounded portion that is rounded at a proximal end,
The negative electrode tab has a second rounded portion that is rounded at the proximal end,
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 in the second direction orthogonal to the first direction in the negative electrode tab on the tip side from the second rounded portion is the width in the second direction in the positive electrode tab on the tip side from the first rounded portion. The electrical storage element as described in any one of Claims 1-3 smaller than. The positive electrode plate and the negative electrode plate are wound,
The storage element according to any one of claims 1 to 4, wherein a winding axis of the electrode body is along the first direction. The positive electrode plate and the negative electrode plate are wound,
A plurality of the positive electrode tabs are arranged at intervals in the second direction, and are arranged side by side along the direction of lamination 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 direction of lamination to form a negative electrode tab bundle,
The electrical 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 in the second direction. The at least one of each of the said some positive electrode tabs which comprise the said positive electrode tab bundle, and each of the said some negative electrode tabs which comprise the said negative electrode tab bundle is shifted and located in the said 2nd direction. Power storage element. A container,
The electric storage element according to claim 6 or 7, wherein the electrode body is accommodated in the container in a state where the positive electrode tab bundle and the negative electrode tab bundle are bent. A container, and a gas discharge valve provided on a wall portion of the container facing the positive electrode tab and the negative electrode tab,
The electricity storage device according to any one of claims 1 to 8, wherein the gas discharge valve is positioned closer to the positive electrode tab than the negative electrode tab in the second direction. The electricity storage device according to claim 9, wherein the positive electrode tab and the negative electrode tab are arranged at positions that do not overlap the gas exhaust valve when viewed from a direction from the wall portion toward the positive electrode tab and the negative electrode tab.