JP2017120743A - Power storage device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a power storage device which can simplify the connection structure of a current collector and an electrode body while achieving a high energy density of the electrode body.SOLUTION: A power storage device 100 comprises: an electrode body 20 having a laminate including a positive electrode 21 and a negative electrode 22; and a positive electrode current collector 50 and a negative electrode current collector 60 which are connected to ends 20b and 20c of the electrode body 20 in a direction crossing a laminating direction of the positive electrode 21 and the negative electrode 22. In the power storage device 100, a leg part 52 of the positive electrode current collector 50 is connected to a positive electrode collecting tab group 26 of each of flat wall-like parts 24a and 24b which are parts opposed to each other at the end 20b of the electrode body 20. A leg part 62 of the negative electrode current collector 60 is connected to a negative electrode collecting tab group 27 of each of flat wall-like parts 24a and 24b which are opposed to each other at the end 20c of the electrode body 20.SELECTED DRAWING: Figure 4

Description

  The present invention relates to a power storage device including an electrode body having stacked electrode plates and a current collector connected to the electrode body.

  Some power storage elements such as lithium ion secondary batteries include an electrode body having positive and negative electrodes alternately stacked and a current collector connected to the electrode body. For example, the current collector is electrically connected to the electrode terminal of the power storage element.

  Patent Document 1 describes a non-aqueous electrolyte secondary battery including a flat wound electrode body in which a positive electrode plate and a negative electrode plate are wound with a separator interposed therebetween, that is, a storage element. Yes. In the electrode body, at one end portion of the positive electrode plate formed by applying the positive electrode active material mixture to the positive electrode core body, a positive electrode core exposed portion in which the positive electrode core body is exposed in a strip shape is formed. Similarly, at one end portion of the negative electrode plate formed by applying the negative electrode active material mixture to the negative electrode core, a negative electrode core exposed portion in which the negative electrode core is exposed in a strip shape is formed. Each of the stacked positive electrode core exposed portion and negative electrode core exposed portion is a flat portion of the electrode body, and is divided into two and concentrated. Each of the two divided positive electrode core exposed portions is sandwiched between the positive electrode current collector and the positive electrode conductive member and joined to the positive electrode current collector by resistance welding. Similarly, each of the two divided negative electrode core exposed portions is sandwiched between the negative electrode current collector and the negative electrode conductive member and joined to the negative electrode current collector by resistance welding. Thus, each of the divided positive electrode core exposed portions is electrically connected to the positive electrode terminal via the positive electrode current collector, and each of the divided negative electrode core exposed portions is connected via the negative electrode current collector. Electrically connected to the negative terminal.

JP 2014-35938 A

  At the time of resistance welding at the positive electrode in the electrode body described in Patent Document 1, two positive electrode conductive members positioned opposite to each other inside the positive electrode core exposed portion are resin-made positive electrodes disposed between them. Is held by the intermediate member. Further, the pair of resistance welding electrodes are brought into contact with the two positive electrode current collectors outside the positive electrode core exposed portion from the outside. And resistance welding is implemented, applying a pressure between a pair of resistance welding electrodes. The intermediate member for positive electrode functions as a jig for maintaining the positional relationship between the pair of resistance welding electrodes and the current collector for positive electrode. The same applies to resistance welding at the negative electrode.

  For example, in order to simplify the connection structure between the current collector and the electrode body, one positive electrode current collector may be welded to one positive electrode core exposed portion. In this case, the two positive electrode core exposed portions located opposite to each other in the electrode body are gathered together, and the positive electrode current collector is welded to the positive electrode core exposed portions gathered together. However, it is difficult to consolidate, that is, focus, all of the multi-layer positive electrode cores in the exposed portion of the positive electrode core, and to weld all of the converged multi-layer positive electrode cores to the positive electrode current collector. Even difficult. Therefore, in order to facilitate focusing and welding, the protruding width from the positive electrode active material mixture of the positive electrode core exposed portion may be increased. However, since the dimensions of the secondary battery, that is, the storage element are usually defined, the area of the positive electrode active material mixture, that is, the active material layer in the electrode body is limited to be small, and the capacity of the electrode body is reduced. Energy density is reduced. The same applies to the negative electrode of the electrode body.

  The present invention has been made to solve the above-described problems, and provides a power storage element that simplifies the connection structure between a current collector and an electrode body while increasing the energy density of the electrode body. For the purpose.

  In order to achieve the above object, a power storage device according to the present invention includes an electrode body having stacked electrode plates, and a current collector connected to an end of the electrode body in a direction crossing the stacking direction of the electrode plates. The one leg part of a collector is connected to each connection part of the site | part which opposes in the edge part of an electrode body.

  In the above-described configuration, the number of layers of the electrode plates to be converged at each connection portion is reduced by connecting one leg portion of the current collector to a plurality of connection portions at the end of the electrode body. This facilitates focusing of the electrode plates at the connection portion, and further facilitates connection between the electrode plate having a reduced number of layers and one leg portion of the current collector. Therefore, the connection structure between the current collector and the electrode body can be simplified. Furthermore, the connection part of the electrode body that can be easily connected to the focusing and current collector can reduce the size of the connection part. Thereby, the restriction of the area of the active material layer in the electrode plate due to the size of the connecting portion is relaxed. Therefore, the energy density of the electrode body can be increased.

  The plurality of connecting portions may be shifted in the extending direction of the leg portions. With the above-described configuration, it is possible to separate the connection position of the current collector leg from the connection portion, and thus the connection between the leg portion and the connection portion is facilitated.

  The connecting portion may be constituted by a tab of the electrode body that protrudes in a direction intersecting with the stacking direction of the electrode plates. In the above-described configuration, it is only necessary to connect the leg portion of the current collector to the protruding tab, so that the connection structure between the current collector and the electrode body can be simplified. Furthermore, the degree of freedom of the shape of the current collector is increased, and the structure of the current collector can be simplified.

  The electrode body includes a positive electrode connecting portion at one end portion of the electrode body in a direction intersecting with the stacking direction of the electrode plates, and one end portion of the electrode body in a direction intersecting with the stacking direction of the electrode plates; A different end portion may include a negative electrode connection portion. With the above-described configuration, the current collector for the positive electrode and the current collector for the negative electrode are connected to different end portions of the electrode body, so that the connection between each current collector and the electrode body is facilitated.

  The electrode body may be formed by winding an electrode plate. Furthermore, the plurality of connecting portions may be arranged substantially evenly along the winding direction of the electrode body. With the above-described configuration, it is possible to equalize the current load at each connection portion.

  The electrode body may include a flat portion that faces each other and a curved portion that connects the flat portions, and the connection portion may be positioned on the flat portions that face each other. With the above-described configuration, the electrode body and the current collector can be made flat. And the connection part in the flat part of an electrode body and the connection of the leg part of an electrical power collector are easy.

  According to the electricity storage device of the present invention, the connection structure between the current collector and the electrode body can be simplified while increasing the energy density of the electrode body.

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 the perspective view which removed the container main body from the electrical storage element of FIG. FIG. 3 is a perspective view in which a part of the electrode body of FIG. 2 is developed. It is the side view which looked at the electrode body and negative electrode collector of the electrical storage element of FIG. 2 from the negative electrode collector side. It is the side view which looked at the electrode body of the electrical storage element of FIG. 2, and the positive electrode current collector from the positive electrode current collector side. It is a front view of the electrical storage element of FIG. It is a disassembled perspective view of the electrical storage element of FIG. FIG. 3 is a side view of the electricity storage device of FIG. 2 as viewed from the negative electrode current collector side. FIG. 3 is a side view of the electricity storage device of FIG. 2 as viewed from the positive electrode current collector side. It is a side view which shows another example of the connection aspect of the negative electrode current collection tab group of the electrode body of FIG. 4, and a negative electrode current collector. FIG. 4 is a view of an enlarged cross section passing through the winding axis of the electrode body of FIG. 3 and substantially perpendicular to the flat direction of the electrode body as seen from the direction XI.

  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 constituent elements, 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 accompanied by “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 of this invention is demonstrated. In the following embodiment, description will be made assuming that the power storage element 100 has a wound electrode body constituted by a wound electrode plate.

  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 power storage element 100 is a secondary battery capable of charging and discharging electricity. 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 or a capacitor. The storage element 100 includes a flat rectangular parallelepiped container 10, the electrode body 20, the positive electrode current collector 50, the negative electrode current collector 60, and the positive electrode terminal 30 and the negative electrode terminal 40 shown in FIG. And. 2 is a perspective view in which the container main body 11 of the container 10 is removed from the power 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 opening 11a of the container body 11. The container body 11 has a flat rectangular parallelepiped outer shape. The shape of the opening 11a is an elongated rectangular shape. On the outer surface 12 a of the lid body 12, the positive terminal 30 and the negative terminal 40 are disposed.

  The container main body 11 and the lid body 12 can be joined with each other in an airtight state by a joining method such as welding. Thereby, the container 10 forms the space sealed inside. The container body 11 and the lid body 12 can be made of a material that is not deformed and does not impair the airtightness of the joint when the internal pressure of the container 10 increases. Although it does not limit, the container main body 11 and the cover body 12 can be produced from weldable metals, such as stainless steel, aluminum, aluminum alloy, for example.

  Moreover, although liquid, such as electrolyte solution (this embodiment nonaqueous electrolyte), is enclosed in the container 10, illustration of the said liquid is abbreviate | omitted. As the electrolytic solution 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.

  Referring to FIG. 2, the positive electrode terminal 30 and the negative electrode terminal 40 are electrically connected to the positive electrode current collector 50 and the negative electrode current collector 60 on the side opposite to the outer surface 12 a of the lid body 12. The positive electrode current collector 50 and the negative electrode current collector 60 are further connected to the electrode body 20. Therefore, the electrode body 20 is provided so as to be suspended from the lid body 12 via the positive electrode current collector 50 and the negative electrode current collector 60. The electrode body 20 is housed in the container body 11 together with the positive electrode current collector 50 and the negative electrode current collector 60. In addition, 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.

  The electrode body 20 is a power generation element that can store electricity. The electrode body 20 is formed by winding the positive electrode 21 and the negative electrode 22 shown in FIG. 3 in a spiral manner around the winding axis A via the separator 23, and is flat. It has an outer shape. The winding axis A is a virtual axis indicated by a one-dot chain line in FIG. 2, and the electrode body 20 has a substantially symmetric configuration with respect to the winding axis A. The winding axis A extends in a direction intersecting with the stacking direction of the positive electrode 21 and the negative electrode 22, and extends along the longitudinal direction of the lid body 12. The electrode body 20 is disposed in a direction in which an outer peripheral portion extending along the winding direction is opposed to the lid body 12. The electrode body 20 having the arrangement configuration as described above is called a vertically wound electrode body.

  Here, in the following description and drawings, the winding axis A direction of the electrode body 20 of the energy storage device 100 is referred to as the X-axis direction. Accordingly, as shown in FIGS. 1 and 2, the positive electrode current collector 50 and the negative electrode current collector 60 are arranged along the X-axis direction, and the positive electrode terminal 30 and the negative electrode terminal 40 are arranged along the X-axis direction. It is out. And the elongate rectangular short side surface which the container main body 11 opposes is located in a line along the X-axis direction.

  Furthermore, the up-down direction of the energy storage device 100 along the direction from the container body 11 toward the lid 12 and perpendicular to the X-axis is referred to as a Z-axis direction. Therefore, the positive electrode current collector 50 and the negative electrode current collector 60 protrude from the lid body 12 in the Z-axis direction and extend along the Z-axis direction. And the long side of the elongate short side surface of the container main body 11 extends along the Z-axis direction. Note that, depending on the usage mode, the storage element 100 may not be arranged with the Z-axis direction as the vertical direction, and thus the Z-axis direction is not necessarily limited to the vertical direction.

  A direction perpendicular to the X-axis direction and the Z-axis direction is referred to as a Y-axis direction. Therefore, the wide long side surface which the container main body 11 opposes is located in a line along the Y-axis direction, and the short side of the short side surface of the container main body 11 extends along the Y-axis direction. Furthermore, the Y-axis direction can be defined as the thickness direction of the container 10.

  Next, a detailed configuration of the electrode body 20 will be described with reference to FIG. FIG. 3 is a perspective view showing a developed part of the electrode body 20 of FIG. The electrode body 20 includes a positive electrode 21 in the shape of a long belt-like sheet, a negative electrode 22 in the shape of a long belt-like sheet, and a separator 23 in the shape of a long belt-like sheet, which are stacked in layers. It is out. The electrode body 20 is formed by winding the positive electrode 21, the negative electrode 22, and the separator 23 stacked in layers in a spiral shape in the winding direction B around the winding axis A. In the present embodiment, the positive electrode 21, the negative electrode 22, and the separator 23 that have started to be wound are rotated around the winding axis A in the winding direction B, which is the clockwise direction in FIG. It is assumed that the unwrapped belt-like positive electrode 21, negative electrode 22, and separator 23 are wound. That is, the winding direction B is the rotation direction of the electrode body 20 during winding. Here, the positive electrode 21 and the negative electrode 22 are examples of an electrode plate.

  The positive electrode 21 is formed by laminating a positive electrode active material layer by a method such as coating on a positive electrode base material layer that is a long metal foil made of metal such as aluminum or aluminum alloy. The negative electrode 22 is formed by laminating a negative electrode active material layer on a negative electrode base material layer, which is a long metal foil made of metal such as copper or copper alloy, by a method such as coating. The separator 23 is a microporous sheet made of a material having electrical insulation properties such as a resin. 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.

  On one edge 22c of the two edges 22b and 22c along the longitudinal direction of the negative electrode 22, a plurality of negative electrode current collecting tabs 22a are integrally formed at intervals in the longitudinal direction. The negative electrode current collecting tabs 22 a are arranged so that there are two negative electrode current collecting tabs 22 a per one turn of the negative electrode 22 centering on the winding axis A. The negative electrode current collecting tab 22 a protrudes from the edge 22 c in the winding axis A direction orthogonal to the longitudinal direction of the negative electrode 22. The negative electrode current collection tab 22a is comprised by the exposed negative electrode base material layer, and does not contain a negative electrode active material layer. A negative electrode active material layer is laminated in a region of the negative electrode 22 other than the negative electrode current collecting tab 22a.

  The separator 23 is formed wider than the negative electrode 22 in the winding axis A direction so as to cover the entire negative electrode 22 except the negative electrode current collecting tab 22a. Two separators 23 are provided on flat main surfaces on both sides of one negative electrode 22, and extend so as to enclose the negative electrode 22. At this time, the negative electrode current collecting tab 22 a protrudes from the separator 23 through between the two separators 23.

  Further, one positive electrode 21 is provided on the separator 23 so as to be positioned inside the negative electrode 22 and further inside the separator 23 adjacent to the negative electrode 22 during winding. A plurality of positive electrode current collecting tabs 21a are integrally formed at intervals in the longitudinal direction on the edge 21b opposite to the negative electrode current collecting tab 22a of the two edges 21b and 21c along the longitudinal direction of the positive electrode 21. ing. The positive electrode current collecting tabs 21a are arranged so that there are two positive electrode current collecting tabs 21a per one turn of the positive electrode 21 around the winding axis A. The positive electrode current collecting tab 21a protrudes from the edge 21b in the winding axis A direction. The positive electrode current collecting tab 21a is composed of an exposed positive electrode base material layer and does not include a positive electrode active material layer. A positive electrode active material layer is laminated in a region other than the positive electrode current collecting tab 21 a in the positive electrode 21.

  The positive electrode 21 is formed narrower in the winding axis A direction than the negative electrode 22 so that the entire positive electrode 21 excluding the positive electrode current collecting tab 21 a is covered with the negative electrode 22. The positive electrode 21 stacked on the separator 23 has the entire surface except the positive electrode current collecting tab 21 a face the negative electrode 22. The positive electrode current collecting tab 21 a protrudes from the separator 23. At this time, each of the positive electrode current collecting tabs 21 a of the positive electrode 21 is positioned side by side with each of the negative electrode current collecting tabs 22 a of the negative electrode 22 in the winding axis A direction.

  One positive electrode 21, one negative electrode 22, and two separators 23 laminated as described above are wound together in a spiral shape in the winding direction B around the winding axis A, thereby A body 20 is formed. In the present embodiment, the electrode body 20 is formed to have an oval cross-sectional shape that is flat in the YZ plane direction. 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.

  Further, FIG. 4 and FIG. 5 will be referred to in addition to FIG. 4 is a side view of the electrode body 20 and the negative electrode current collector 60 of the energy storage device 100 of FIG. 2 as viewed from the negative electrode current collector 60 side. FIG. 5 is a side view of the electrode body 20 and the positive electrode current collector 50 of the power storage device 100 of FIG. 2 as viewed from the positive electrode current collector 50 side. In the electrode body 20, the stacked positive electrode 21, negative electrode 22, and separator 23 form a wall-like body extending along the winding direction B that is the clockwise direction in FIG. 4. Specifically, the wall-like body includes two flat wall-like portions 24a and 24b that are wide and flat, and two curved wall-like portions 24c and 24d that are curved in a semicircular shape.

  The flat wall portions 24 a and 24 b are positioned to face each other with the winding start portion 25 interposed therebetween. The curved wall portions 24c and 24d are positioned to face each other via the winding start portion 25, and connect the flat wall portions 24a and 24b to each other. The winding start portion 25 is a portion inside the first winding of the stacked positive electrode 21, negative electrode 22 and separator 23. The winding start portion 25 is a flat gap along the flat wall portions 24a and 24b when there is a gap between the facing portions of the first winding, and the facing portions of the first winding are in close contact with each other. If it is, it is a surface along the flat wall portions 24a and 24b. The winding start portion 25 is located at the position of the winding axis A, and extends along the direction from the curved wall portion 24c toward the curved wall portion 24d and the winding axis A direction. Here, the flat wall-like portions 24 a and 24 b are examples of opposing portions and flat portions in the electrode body 20, and the curved wall-like portions 24 c and 24 d are examples of the curved portion of the electrode body 20.

  3 and 4 together, in the electrode body 20 on which the positive electrode 21, the negative electrode 22, and the separator 23 are wound, the electrode body 20 formed by the edge 22 c of the laminated negative electrode 22 and the edge 21 c of the positive electrode 21. At the end 20c, the plurality of negative electrode current collecting tabs 22a are gathered at two separate positions. That is, the plurality of negative electrode current collecting tabs 22a form two negative electrode current collecting tab groups 27 that are positioned apart from each other. Note that the end portion 20c is an end portion in the winding axis A direction of the flat wall portions 24a and 24b and the curved wall portions 24c and 24d, that is, an end portion in a direction intersecting the stacking direction of the positive electrode 21 and the negative electrode 22. When configured and viewed from the negative electrode current collector 60 side, an oval shape is formed. In each of the negative electrode current collecting tab groups 27, the negative electrode current collecting tabs 22a are overlapped in the Y-axis direction, positioned in alignment with each other, and bundled together, that is, converged. Further, at the end portion 20c, the positive electrode 21 and the negative electrode 22 are focused in the Y-axis direction in the flat wall portions 24a and 24b, respectively. Here, the negative electrode current collecting tab group 27 is an example of a connection portion of the electrode body 20 and a tab of the electrode body 20.

  The negative electrode current collecting tab group 27 is located on the flat wall portions 24 a and 24 b of the electrode body 20, respectively. Therefore, the two negative electrode current collecting tab groups 27 are positioned with a gap in the Y-axis direction. Further, the two negative electrode current collecting tab groups 27 are also spaced apart in the Z-axis direction. And the two negative electrode current collection tab groups 27 are arrange | positioned so that it may distribute substantially along the winding direction B on the electrode body 20, ie, along the winding direction B, on the edge part 20c. . Specifically, the distance C2 along the winding direction B is opposite to the winding direction B with respect to the distance from the one negative electrode current collecting tab group 27 to the other negative electrode current collecting tab group 27 on the end portion 20c. It is equivalent to the distance D2 along the direction. That is, the positional relationship between one negative electrode current collecting tab group 27 and the other negative electrode current collecting tab group 27 is substantially symmetric with respect to the winding axis A. Specifically, in the side view of the electrode body 20 when the electrode body 20 as shown in FIG. 4 is viewed from the negative electrode current collector 60 side, the two negative electrode current collection tab groups 27 constitute the center point of the electrode body 20. The points on the winding axis A are arranged at substantially point-symmetrical positions. Thereby, the area | region which each of the negative electrode current collection tab group 27 can collect and supply electric power in the electrode body 20, ie, the area | region which bears current collection and electric power feeding, becomes substantially equal. And also about each one turn of the negative electrode 22, the current collection and electric power feeding area | region which the two negative electrode current collection tabs 22a which exist in one turn bear become substantially equal. Note that “substantially equal” includes a case where the distance is exactly equal and a case where there is a slight difference but it can be regarded as being substantially equal.

  3 and 5 together, the plurality of positive electrode current collecting tabs 21a are separated from each other even at the end portion 20b of the electrode body 20 formed by the edge 21b of the stacked positive electrode 21 and the edge 22b of the negative electrode 22. The two positive electrode current collecting tab groups 26 are formed at the positions. Note that the end portion 20b is an end portion of the flat wall portions 24a and 24b and the curved wall portions 24c and 24d in the winding axis A direction, that is, an end portion in a direction crossing the stacking direction of the positive electrode 21 and the negative electrode 22. When formed from the positive electrode current collector 50 side, an oval shape is formed. In each positive electrode current collecting tab group 26, the positive electrode current collecting tabs 21a are positioned in alignment with each other so as to overlap in the Y-axis direction and are bundled together, that is, converged. Further, at the end portion 20b, the positive electrode 21 and the negative electrode 22 are converged in the Y-axis direction in the flat wall portions 24a and 24b, respectively. Here, the positive electrode current collecting tab group 26 is an example of a connection portion of the electrode body 20 and a tab of the electrode body 20.

  Each of the positive electrode current collecting tab groups 26 is located on the flat wall portions 24a and 24b of the electrode body 20, and is spaced from each other in the Y-axis direction. Further, the two positive electrode current collecting tab groups 26 are also located at intervals in the Z-axis direction. And the two positive electrode current collection tab groups 26 are arrange | positioned so that it may distribute substantially along the winding direction B on the electrode body 20, ie, along the winding direction B, on the edge part 20b. . On the end 20b, the distance C1 along the winding direction B is the distance along the direction opposite to the winding direction B with respect to the distance from the one positive electrode current collecting tab group 26 to the other positive electrode current collecting tab group 26. Equivalent to D1. That is, the positional relationship between the one positive electrode current collecting tab group 26 and the other positive electrode current collecting tab group 26 is substantially symmetric with respect to the winding axis A. Specifically, when the electrode body 20 as shown in FIG. 5 is viewed from the side of the positive electrode current collector 50, the two positive electrode current collection tab groups 26 constitute the center point of the electrode body 20. The points on the winding axis A are arranged at substantially point-symmetrical positions. Therefore, the area where each of the positive electrode current collecting tab groups 26 can collect and supply power in the electrode body 20, that is, the area responsible for collecting and supplying power is substantially equal. And also about each one turn of the positive electrode 21, the current collection and electric power feeding area | region which the two positive electrode current collection tabs 21a which exist in one turn bear are substantially equal.

  Further, the two positive electrode current collecting tab groups 26 and the two negative electrode current collecting tab groups 27 are arranged at substantially symmetrical positions with respect to the YZ plane.

  Next, detailed configurations of the positive electrode terminal 30, the negative electrode terminal 40, the positive electrode current collector 50, and the negative electrode current collector 60 will be described with reference to FIGS. 6 is a front view of the electricity storage device 100 of FIG. 2 as viewed from the flat wall portion 24a of the electrode body 20 toward the flat wall portion 24b. FIG. 7 is an exploded perspective view showing the elements of the electricity storage device 100 of FIG. 2 in an exploded manner. FIG. 8 is a side view of the electricity storage device 100 of FIG. 2 as viewed from the negative electrode current collector 60 side. FIG. 9 is a side view of the electricity storage device 100 of FIG. 2 as viewed from the positive electrode current collector 50 side.

  Referring to FIGS. 6 and 7 together, the positive electrode terminal 30 includes a terminal body 31, an upper insulating member 32, and a lower insulating member 33. The negative electrode terminal 40 includes a terminal body 41, an upper insulating member 42, and a lower insulating member 43. The terminal bodies 31 and 41 are made of a conductive material such as metal. Cylindrical rivet portions 31a and 41a are formed so as to protrude from the flat terminal bodies 31 and 41, respectively. The upper insulating members 32 and 42 and the lower insulating members 33 and 43 are made of an electrically insulating material such as resin. The upper insulating members 32 and 42 and the lower insulating members 33 and 43 are packing in the form of a plate having an edge protruding at the periphery.

  Through holes 32a and 42a through which the rivet portions 31a and 41a can respectively pass are formed in the upper insulating members 32 and 42, respectively. The lower insulating members 33 and 43 are formed with through holes 33a and 43a through which the rivet portions 31a and 41a can pass, respectively. The lid body 12 is formed with through holes 12b and 12c through which the rivet portions 31a and 41a can pass, respectively.

  The positive electrode current collector 50 is configured to be connected to the terminal body 31 of the positive electrode terminal 30 and the two positive electrode current collecting tab groups 26 of the electrode body 20. The positive electrode current collector 50 is a member having conductivity and rigidity. The positive electrode current collector 50 is made of a metal such as aluminum or an aluminum alloy, like the positive electrode base material layer of the electrode body 20. The positive electrode current collector 50 includes a plate-like fixing portion 51 attached to the lid body 12, and an elongated plate-like leg portion 52 formed integrally with the fixing portion 51 and extending from the fixing portion 51. The fixing portion 51 is formed with a through hole 51a through which the rivet portion 31a can pass.

  The rivet portion 31 a of the terminal body 31 includes a through hole 32 a of the upper insulating member 32, a through hole 12 b of the lid body 12, a through hole 33 a of the lower insulating member 33, and a through hole of the fixing portion 51 of the positive electrode current collector 50. After passing through 51a sequentially, it is caulked on the fixing portion 51 side. Thereby, the terminal body 31 of the positive electrode terminal 30 and the fixing portion 51 of the positive electrode current collector 50 are attached and fixed to the lid body 12 together with the upper insulating member 32 and the lower insulating member 33. At this time, the terminal body 31 is physically and electrically connected to the positive electrode current collector 50. The upper insulating member 32 is interposed between the terminal body 31 and the lid body 12 to electrically insulate the terminal body 31 and the lid body 12. The lower insulating member 33 is interposed between the lid body 12 and the fixing portion 51 and electrically insulates the lid body 12 and the positive electrode current collector 50 from each other.

  The connection structure of the terminal main body 31, the upper insulating member 32, the lid body 12, the lower insulating member 33, and the fixing portion 51 of the positive electrode current collector 50 is not limited to riveting, but the upper insulating member 32, the lid Any structure may be used as long as the terminal body 31 and the fixing portion 51 are connected to each other with the body 12 and the lower insulating member 33 interposed therebetween. For example, bolts and nuts may be used in place of the rivet portion 31 a, and the rivet portion 31 a may be welded to the fixed portion 51.

  The negative electrode current collector 60 is configured to be connected to the terminal body 41 of the negative electrode terminal 40 and the two negative electrode current collecting tab groups 27 of the electrode body 20. The negative electrode current collector 60 is a member having conductivity and rigidity. The negative electrode current collector 60 is made of a metal such as copper or a copper alloy, similarly to the negative electrode base material layer of the electrode body 20. The negative electrode current collector 60 includes a plate-like fixing portion 61 attached to the lid body 12, and an elongated plate-like leg portion 62 that is formed integrally with the fixing portion 61 and extends from the fixing portion 61. The fixing portion 61 is formed with a through hole 61a through which the rivet portion 41a of the terminal body 41 of the negative electrode terminal 40 can pass.

  The rivet portion 41 a of the terminal body 41 includes a through hole 42 a of the upper insulating member 42, a through hole 12 c of the lid body 12, a through hole 43 a of the lower insulating member 43, and a through hole of the fixing portion 61 of the negative electrode current collector 60. After passing sequentially through 61a, it is caulked on the fixing portion 61 side. Thereby, the terminal main body 41 of the negative electrode terminal 40 and the fixing portion 61 of the negative electrode current collector 60 are attached and fixed to the lid body 12 together with the upper insulating member 42 and the lower insulating member 43. At this time, the terminal body 41 is physically and electrically connected to the negative electrode current collector 60. The upper insulating member 42 is interposed between the terminal body 41 and the lid body 12 and electrically insulates the terminal body 41 and the lid body 12. The lower insulating member 43 is interposed between the lid body 12 and the fixing portion 61 and electrically insulates the lid body 12 and the negative electrode current collector 60.

  The connection structure of the terminal main body 41, the upper insulating member 42, the lid 12, the lower insulating member 43, and the fixing portion 61 of the negative electrode current collector 60 is not limited to riveting, but the upper insulating member 42, the lid Any structure that connects the terminal body 41 and the fixing portion 61 with the body 12 and the lower insulating member 43 interposed therebetween may be used. For example, bolts and nuts may be used in place of the rivet portion 41a, and the rivet portion 41a may be welded to the fixed portion 61.

  Furthermore, with reference to FIG.4 and FIG.8, the structure of the leg part 62 of the negative electrode collector 60 and the connection aspect of the leg part 62 and the negative electrode current collection tab group 27 of the electrode body 20 are demonstrated. The leg portion 62 of the negative electrode current collector 60 attached to the lid body 12 extends along the Z-axis direction from the fixed portion 61 with bending in the Y-axis direction. Specifically, the leg portion 62 includes an elongated plate-like first straight leg portion 62 a located adjacent to the flat wall portion 24 b of the electrode body 20. The first straight leg portion 62a extends linearly from the curved wall-like portion 24c of the electrode body 20 toward the curved wall-like portion 24d substantially in parallel with the extending direction of the flat wall-like portion 24b. The first straight leg portion 62a extends from the fixed portion 61 to the vicinity of an intermediate position between the curved wall portion 24c and the curved wall portion 24d. Furthermore, one of the two flat long side surfaces, which are the opposite surfaces of the wide side of the first straight leg portion 62a, is adjacent to the negative electrode current collecting tab group 27 of the flat wall portion 24b on the winding start portion 25 side. .

  Furthermore, the leg part 62 includes an elongated plate-like second straight leg part 62b positioned adjacent to the flat wall part 24a of the electrode body 20. The second straight leg portion 62b extends linearly from the curved wall-like portion 24c toward the curved wall-like portion 24d substantially in parallel with the extending direction of the flat wall-like portion 24a and the first straight leg portion 62a. The second straight leg portion 62b extends from the vicinity of an intermediate position between the curved wall-shaped portion 24c and the curved wall-shaped portion 24d toward the curved wall-shaped portion 24d, and further, the negative electrode current collector of the flat wall-shaped portion 24a. It extends beyond the tab group 27. One of the two flat long side surfaces, which are the opposite surfaces of the wide side of the second straight leg portion 62b, is adjacent to the negative electrode current collecting tab group 27 of the flat wall portion 24a on the winding start portion 25 side.

  Furthermore, the leg portion 62 is an elongated plate-like connecting leg that connects the first straight leg portion 62a and the second straight leg portion 62b in the vicinity of an intermediate position between the curved wall portion 24c and the curved wall portion 24d. Part 62c is included. The connecting leg portion 62 c extends linearly so as to cross the winding start portion 25.

  Therefore, the leg part 62 has a shape that bends at the connecting leg part 62c so as to offset the first straight leg part 62a and the second straight leg part 62b in the direction from the flat wall part 24b toward the flat wall part 24a. Have. And the 1st straight leg part 62a is joined to the negative electrode current collection tab group 27 of the flat wall-shaped part 24b by welding, such as ultrasonic welding and resistance welding, in the long side. The second straight leg portion 62b is joined to the negative electrode current collecting tab group 27 of the flat wall portion 24a on the long side surface by the same welding or the like. Since the leg part 62 has the shape as described above, the two negative electrode current collecting tab groups 27 are joined without being subjected to excessive force such as being pulled.

  The bent shape of the leg portion 62 as described above can be formed simply by bending the leg portion 62 when the negative electrode current collector 60 is formed. Alternatively, when the negative electrode current collector 60 is cast, the bent shape of the leg portion 62 can be formed at the time of casting.

  As shown in FIGS. 5 and 9, the leg part 52 of the positive electrode current collector 50 has the same configuration as the leg part 62 of the negative electrode current collector 60. The leg portion 52 connects a straight elongated plate-like first straight leg portion 52a, a straight elongated plate-like second straight leg portion 52b, and the first straight leg portion 52a and the second straight leg portion 52b. And a straight elongated plate-like connecting leg portion 52c. The leg portion 52 includes a connecting leg portion 52c so that the first straight leg portion 52a and the second straight leg portion 52b extending substantially in parallel with each other are offset in the direction from the flat wall portion 24b toward the flat wall portion 24a. It has a shape that bends. The first straight leg portion 52a extends from the fixed portion 51 to the vicinity of an intermediate position between the curved wall portion 24c and the curved wall portion 24d of the electrode body 20. One of the two flat long side surfaces, which are the opposite surfaces of the wide side of the first straight leg portion 52a, is adjacent to the positive electrode current collecting tab group 26 of the flat wall-shaped portion 24b of the electrode body 20 on the winding start portion 25 side. . And the 1st straight leg part 52a is joined to the said positive electrode current collection tab group 26 in the long side.

  The second straight leg portion 52b extends from the vicinity of an intermediate position between the curved wall portion 24c and the curved wall portion 24d toward the curved wall portion 24d, and further, the flat wall portion 24a of the electrode body 20. It extends beyond the positive electrode current collecting tab group 26. One of the two flat long side surfaces, which are the opposite surfaces of the wider side of the second straight leg portion 52b, is adjacent to the positive electrode current collecting tab group 26 of the flat wall portion 24a on the winding start portion 25 side. And the 2nd straight leg part 52b is joined to the said positive electrode current collection tab group 26 in the long side.

  In the configuration shown in FIGS. 4 and 5, the leg portion 52 of the positive electrode current collector 50 is positioned inside the two positive electrode current collection tab groups 26, that is, on the winding start portion 25 side. Although the part 62 is located inside the two negative electrode current collecting tab groups 27, that is, on the winding start part 25 side, the present invention is not limited to this.

  Like the negative electrode current collector 60 shown in FIG. 10, the first straight leg portion 62 a and the second straight leg portion 62 b of the leg portion 62 are respectively opposite to the winding start portion 25 with respect to the negative electrode current collecting tab group 27. May be located adjacent to each other. 10 is a side view showing another example of a connection mode between the negative electrode current collector tab group 27 and the negative electrode current collector 60 of the electrode body 20 of FIG. The leg part 62 of the negative electrode current collector 60 shown in FIG. 10 has the same configuration as the leg part 62 of the negative electrode current collector 60 shown in FIG. The first straight leg portion 62a is joined to the negative electrode current collecting tab group 27 of the flat wall-like portion 24b of the electrode body 20, and the second straight leg portion 62b is joined to the negative electrode current collecting tab group 27 of the flat wall-like portion 24a. Be joined. In addition, the connection aspect of the positive electrode current collection tab group 26 of the electrode body 20 and the positive electrode current collector 50 can also be made the same as the above-mentioned aspect.

  As described above, the electricity storage device 100 according to the present embodiment includes the electrode body 20 having the stacked positive electrode 21 and negative electrode 22, and the end of the electrode body 20 in a direction crossing the stacking direction of the positive electrode 21 and negative electrode 22. A positive electrode current collector 50 and a negative electrode current collector 60 connected to the parts 20b and 20c. In the electric storage element 100, one leg portion 52 of the positive electrode current collector 50 is connected to the positive electrode current collecting tab group 26 in each of the portions of the flat wall portions 24a and 24b that are opposite portions in the end portion 20b of the electrode body 20. Is done. In addition, one leg 62 of the negative electrode current collector 60 is connected to the negative electrode current collection tab group 27 at each of the flat wall portions 24a and 24b, which are opposite portions of the end 20c of the electrode body 20.

  In the above-described configuration, since one leg portion 52 of the positive electrode current collector 50 is connected to the plurality of positive electrode current collection tab groups 26 at the end 20b of the electrode body 20, the positive current collector tab groups 26 are focused. The number of layers of the positive electrode 21 is reduced. This facilitates focusing of the positive electrode 21 in the positive electrode current collecting tab group 26, and further reduces the number of positive electrode current collecting tab groups 26 of the positive electrode 21 and one leg portion 52 of the positive electrode current collector 50. Connection is easy. Therefore, the connection structure between the positive electrode current collector 50 and the electrode body 20 can be simplified. Furthermore, the size of the positive electrode current collector tab group 26 of the electrode body 20 that is easy to focus and connect to the positive electrode current collector 50 can be reduced. Specifically, the positive electrode current collector tab group 26 in the direction of the winding axis A can be reduced. The width of the positive electrode current collecting tab group 26 can be reduced.

  Similarly, with respect to the negative electrode current collector 60, one leg portion 62 is connected to the plurality of negative electrode current collection tab groups 27 at the end 20 c of the electrode body 20, and thus the negative electrode current collector 60 and the electrode body 20. The connection structure can be simplified. Furthermore, the negative electrode current collection tab group 27 of the electrode body 20 can reduce the size, specifically, the width of the negative electrode current collection tab group 27 in the winding axis A direction.

  When the dimensions of the storage element 100 are defined, the positive electrode active material layer and the negative electrode received by the positive electrode 21 and the negative electrode 22 due to the size of the positive electrode current collection tab group 26 and the negative electrode current collection tab group 27, respectively. The restriction on the area of the active material layer is relaxed. That is, it is possible to increase the width in the winding axis A direction of the positive electrode 21 to which the positive electrode active material layer is applied and the negative electrode 22 to which the negative electrode active material layer is applied. Therefore, the energy density of the electrode body 20 can be increased.

  Furthermore, since the plurality of positive electrode current collecting tab groups 26 connected to one leg portion 52 exist over both the portions of the opposed flat wall portions 24a and 24b in the end portion 20b of the electrode body 20, the positive electrode current collecting tab group 26 exists. Current bias in the electric tab group 26 is reduced. Therefore, the electrical load at the connection portion between the positive electrode current collector 50 and the electrode body 20 is reduced. Similarly, since the plurality of negative electrode current collecting tab groups 27 connected to one leg 62 exist over both of the opposing flat wall portions 24a and 24b in the end portion 20c of the electrode body 20, the negative electrode current collector tab group 27 exists. Current bias in the electric tab group 27 is reduced. Therefore, the electrical load at the connection portion between the negative electrode current collector 60 and the electrode body 20 is reduced.

  Further, for example, when a plurality of positive current collecting tabs 21a are provided per one turn of the positive electrode 21 with respect to the positive current collecting tabs 21a forming the plurality of positive current collecting tab groups 26, the current collecting in each positive current collecting tab 21a The distance to the end of the region can be shortened. Similarly, regarding the negative electrode current collecting tabs 22a forming the plurality of negative electrode current collecting tab groups 27, when a plurality of negative electrode current collecting tabs 22a are provided per turn of the negative electrode 22, current collecting regions in the respective negative electrode current collecting tabs 22a The distance to the end of can be shortened. Therefore, the concentration of current load in the positive electrode current collecting tab 21a and the negative electrode current collecting tab 22a is reduced.

  In the power storage device 100 according to the present embodiment, the plurality of positive electrode current collector tab groups 26 and the plurality of negative electrode current collector tab groups 27 are respectively formed with the leg portions 52 of the positive electrode current collector 50 and the leg portions 62 of the negative electrode current collector 60. The position is shifted in the extending direction. In the above-described configuration, the connection position between the leg 52 and the positive electrode current collecting tab group 26 in the leg 52 can be separated. Similarly, the connection position between the leg 62 and the negative electrode current collecting tab group 27 in the leg 62 can be separated. Therefore, the leg portions 52 and 62 can be easily connected to the positive electrode current collecting tab group 26 and the negative electrode current collecting tab group 27, respectively. Further, the concentration of current load at the legs 52 and 62 is suppressed.

  In power storage device 100 according to the present exemplary embodiment, electrode body 20 is formed by winding positive electrode 21 and negative electrode 22, and a plurality of positive electrode current collecting tab groups 26 and a plurality of negative electrode current collecting tab groups 27 are respectively electrodes. The body 20 is arranged substantially evenly along the winding direction B. In the above-described configuration, it is possible to equalize the current load in each positive current collecting tab group 26 and each negative current collecting tab group 27.

  In the energy storage device 100 according to the present embodiment, the positive electrode current collector tab group 26 and the negative electrode current collector tab group 27 of the electrode body 20 projecting in the direction intersecting the stacking direction of the positive electrode 21 and the negative electrode 22 are respectively positive electrode current collectors. The connection part with 50 leg parts 52 and the connection part with the leg part 62 of the negative electrode collector 60 are comprised. In the above-described configuration, the leg portion 52 of the positive electrode current collector 50 may be connected to the protruding positive electrode current collection tab group 26. Similarly, the leg portion 62 of the negative electrode current collector 60 may be connected to the protruding negative electrode current collection tab group 27. Therefore, the connection structure between the positive electrode current collector 50 and the negative electrode current collector 60 and the electrode body 20 can be simplified. Furthermore, the freedom degree of the shape of the positive electrode current collector 50 and the negative electrode current collector 60 is increased, and the structure of the positive electrode current collector 50 and the negative electrode current collector 60 can be simplified. Moreover, in the positive electrode 21 and the negative electrode 22, only the positive electrode current collection tab 21a of the positive electrode current collection tab group 26 and the negative electrode current collection tab 22a of the negative electrode current collection tab group 27 should be made into the uncoated part which does not laminate | stack an active material layer. Therefore, unnecessary uncoated parts can be reduced. Therefore, the energy density of the electrode body 20 can be increased.

  In power storage device 100 according to the present exemplary embodiment, electrode body 20 includes flat wall portions 24a and 24b that face each other, and curved wall portions 24c and 24d that connect flat wall portions 24a and 24b to each other. The current collecting tab group 26 and the negative electrode current collecting tab group 27 are located on the flat wall portions 24a and 24b facing each other. In the above-described configuration, the electrode body 20, the positive electrode current collector 50, and the negative electrode current collector 60 can be flattened. And the connection between the positive electrode current collector tab group 26 and the negative electrode current collector tab group 27 in the flat part of the electrode body 20 and the leg part 52 of the positive electrode current collector 50 and the leg part 62 of the negative electrode current collector 60 is as follows. Easy.

  In the energy storage device 100 according to the present embodiment, the electrode body 20 includes a positive electrode current collecting tab group 26 at one end portion 20b of the electrode body 20 in a direction intersecting the stacking direction of the positive electrode 21 and the negative electrode 22. A negative electrode current collecting tab group 27 is included in an end portion 20 c opposite to one end portion 20 b of the electrode body 20 in a direction crossing the stacking direction of the positive electrode 21 and the negative electrode 22. In the above configuration, since the positive electrode current collector 50 and the negative electrode current collector 60 are connected to different ends of the electrode body 20, the positive electrode current collector 50 and the negative electrode current collector 60 are connected to the electrode body 20. Becomes easier. Furthermore, the degree of freedom of the shape of the positive electrode current collector 50 and the negative electrode current collector 60 can be increased, and the structure of the positive electrode current collector 50 and the negative electrode current collector 60 can be simplified.

[Other variations]
The power storage element according to the embodiment of the present invention has been described above, but the present invention is not limited to the embodiment. That is, the embodiment disclosed this time should be considered as illustrative in all points and 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 element 100 according to the embodiment includes one electrode body 20. However, the power storage element may include two or more electrode bodies. Also in the above-described configuration, one leg portion of the current collector can be connected to each of the positive electrode and the negative electrode of one electrode body.

  In the electricity storage device 100 according to the embodiment, the two positive electrode current collecting tab groups 26 and the two negative electrode current collecting tab groups 27 are formed on the electrode body 20, but the present invention is not limited to this. At least one of the positive electrode current collecting tab group and the negative electrode current collecting tab group may be two or more. The number of positive current collecting tab groups and the number of negative current collecting tab groups may be the same or different. Even when one or both of the positive electrode current collecting tab group and the negative electrode current collecting tab group are three or more, the positive electrode current collecting tab group and the negative electrode current collecting tab group are substantially evenly distributed along the winding direction of the electrode body. May be arranged. Also in the above-described configuration, one leg portion of the positive electrode current collector is connected to all the positive electrode current collector tab groups of the electrode body, and one leg portion of the negative electrode current collector is connected to all the negative electrode current collector tab groups. Can be configured.

  In the power storage device 100 according to the embodiment, the positive electrode current collecting tab 21a forming the positive electrode current collecting tab group 26 of the electrode body 20 is formed on the positive electrode 21 so as to exist for each winding. It may be formed every time. Similarly, the negative electrode current collecting tab 22a forming the negative electrode current collecting tab group 27 is also formed on the negative electrode 22 so as to exist for each winding, but may be formed for each of a plurality of windings.

  Moreover, in the electrode body 20 of the electrical storage element 100 according to the embodiment, the two positive electrode current collecting tabs 21 a are formed for each turn of the positive electrode 21 in order to form the two positive electrode current collecting tab groups 26. However, the number of the positive electrode current collecting tabs 21a per turn of the positive electrode 21 may be one. Similarly, the number of the negative electrode current collecting tabs 22 a for forming the two negative electrode current collecting tab groups 27 may be one for each turn of the negative electrode 22. Even when there are three or more positive electrode current collecting tab groups 26 or negative electrode current collecting tab groups 27, two or less positive electrode current collecting tabs 21a or negative electrode current collecting tabs 22a are formed for each turn of the positive electrode 21 or the negative electrode 22. May be.

  Moreover, in the electrode body 20 of the electrical storage element 100 according to the embodiment, the separator 23 is not subjected to the processing on the edge along the winding direction B. However, the present invention is not limited to this. As shown in FIG. 11, the edge portions 23b and 23c on both sides of the separator 23 along the winding direction B, that is, the extending direction thereof may be processed. FIG. 11 is a view of an enlarged cross section viewed from the direction XI that passes through the winding axis A of the electrode body 20 of FIG. 3 and is substantially perpendicular to the flat direction of the electrode body 20. In FIG. 11, an enlarged cross-sectional view of the vicinity of the end portions 20b and 20c of the electrode body 20 is shown.

  Referring to FIG. 11, the positive electrode 21 has a configuration in which a positive electrode active material layer 212 is laminated on the surfaces on both sides of the positive electrode base material layer 211, and the negative electrode 22 is on the surfaces on both sides of the negative electrode base material layer 221. The negative electrode active material layer 222 is stacked. In the end portions 20b and 20c, edge portions protruding from the edges 21b and 21c of the positive electrode 21 in the two separators 23 adjacent to the positive electrode 21 on both sides in the stacking direction of the positive electrode 21, the negative electrode 22 and the separator 23, respectively. It is joined. That is, the edge portions of the two separators 23 are joined so as to cover the edges 21 b and 21 c of the positive electrode 21.

  Specifically, at the end portion 20 b, an edge portion 23 b along the longitudinal direction that is the extending direction of the separator 23 protrudes in a direction from the end portion 20 c toward the end portion 20 b rather than the edge 21 b of the positive electrode 21. Edge portions 23b of two separators 23 adjacent to the positive electrode 21 on both sides are joined to each other along the extending direction of the edge portion 23b by a joining method such as ultrasonic welding or thermal welding. The joint portion may be formed by a joint portion that is continuous along the extending direction of the edge portion 23b, or may be formed by a plurality of joint portions that are arranged with a gap along the extending direction of the edge portion 23b. Alternatively, it may be formed by a number of spot-like joints arranged with a gap along the extending direction of the edge portion 23b. Note that, in the portion where the positive electrode current collecting tab 21a is interposed between the edge portions 23b of the separator 23, the edge portion 23b may not be joined. Or the edge part 23b may be joined to the positive electrode current collection tab 21a by the joining method similar to the above-mentioned. The separator 23 as described above covers the edge 21 b of the positive electrode 21.

  Also in the end portion 20c, the edge portion 23c along the longitudinal direction of the separator 23 protrudes in the direction from the end portion 20b toward the end portion 20c rather than the edge 21c of the positive electrode 21, similarly to the end portion 20b. The edge portions 23c of the two separators 23 adjacent to the positive electrode 21 on both sides are joined to each other along the extending direction of the edge portion 23c by the same joining method as described above. Thereby, the edge 21 c of the positive electrode 21 is covered with the separator 23.

  The separator 23 covers the edges 21 b and 21 c of the positive electrode 21, so that the positive electrode current collector tab group 26 and the positive electrode current collector 50 are welded and the negative electrode current collector tab group 27 and the negative electrode current collector 60 are welded. It is possible to suppress foreign matters such as metal powder and metal particles from the positive electrode current collecting tab 21 a and the negative electrode current collecting tab 22 a that may be generated from adhering to the positive electrode 21. In particular, metal powder, metal particles, and the like from the negative electrode current collecting tab 22a are cationized when attached to the positive electrode 21 having a noble potential, and the cation is deposited as metal when it passes through the separator 23 and arrives at the negative electrode 22. obtain. When the deposited metal is deposited, the separator 23 may be broken to reach the positive electrode 21, and the positive electrode 21 and the negative electrode 22 may be short-circuited. As described above, the separator 23 to which the edge portions 23b and 23c are joined can suppress the occurrence of the short circuit.

  In the above-described configuration, the edge portions 23 b and 23 c of the separator 23 are configured to cover the edges 21 b and 21 c of the positive electrode 21, respectively, but are not limited thereto. The edge portions 23b and 23c of the separator 23 may be configured to cover the edges 22b and 22c of the negative electrode 22, respectively. Alternatively, the edge portions 23 b and 23 c of the separator 23 may be configured to cover the edge 21 b of the positive electrode 21 and the edge 22 c of the negative electrode 22, or to cover the edge 22 b of the negative electrode 22 and the edge 21 c of the positive electrode 21, respectively. Alternatively, only one of the edge portions 23 b and 23 c of the separator 23 may be configured to cover the edge of the positive electrode 21 or the negative electrode 22.

  In the electricity storage device 100 according to the embodiment, the positive electrode current collector tab group 26 and the negative electrode current collector tab group 27 of the electrode body 20 are respectively connected to the leg portion 52 of the positive electrode current collector 50 and the leg portion 62 of the negative electrode current collector 60. Although it was located away along the extending direction, it is not limited to this. One or both of the positive electrode current collecting tab group 26 and the negative electrode current collecting tab group 27 may be positioned so as to face each other. Also in the above-described configuration, for example, by forming the leg part into a U-shaped or U-shaped bent shape, the leg part of the positive electrode current collector and the leg part of the negative electrode current collector are all of the electrode bodies. The positive electrode current collecting tab group and all the negative electrode current collecting tab groups can be connected.

  In the electricity storage device 100 according to the embodiment, the leg portion 52 of the positive electrode current collector 50 and the leg portion 62 of the negative electrode current collector 60 each have a bent shape with an angle, but the present invention is not limited thereto. It is not something. In one or both of the leg part of the positive electrode current collector and the leg part of the negative electrode current collector, the bent part of the leg part or the entire leg part may have a curved shape such as an S shape.

  In power storage device 100 according to the embodiment, fixing portion 51 and leg portion 52 of positive electrode current collector 50 are integrally formed, and fixing portion 61 and leg portion 62 of negative electrode current collector 60 are integrally formed. However, it is not limited to this. In one or both of the positive electrode current collector and the negative electrode current collector, the fixing part and the leg part may be separated.

  The power storage element 100 according to the embodiment is a power storage element having a vertically wound electrode body. However, the electrode body 20 is arranged in a direction in which the end portion 20b or 20c faces the lid body 12 of the container 10. An electricity storage element having a wound electrode body may be used. Furthermore, the positive electrode current collector 50 and the negative electrode current collector 60 may be connected to one end portion of the electrode body 20 or may be connected to two opposite end portions, respectively.

  In the electricity storage device 100 according to the embodiment, the electrode body 20 is a wound electrode body formed by winding one positive electrode and one negative electrode together, but is not limited thereto. . The electrode body may be a stacked type (also referred to as a stack type) electrode body formed by stacking a large number of positive electrodes and a large number of negative electrodes, and the stacked positive and negative electrodes are folded together to form a multi-layer. It may be a Z-shaped electrode body on which the positive electrode and the negative electrode are formed. For example, in the positive electrode of the electrode body, the multi-layer positive electrode is divided into a plurality of assemblies in the stacking direction of the positive electrode and the negative electrode, regardless of whether the electrode is a stacked electrode body or a Z-shaped electrode body. can do. Further, in each assembly including a plurality of layers of positive electrodes, the positive electrode current collecting tab group of the positive electrode located at the end in the direction substantially perpendicular to the stacking direction is focused in the stacking direction, It can be connected to the leg of the positive electrode current collector. Furthermore, the plurality of connecting portions between the plurality of positive electrode current collecting tab groups and the leg portions of the positive electrode current collector can be arranged by being shifted in the extending direction of the leg portions, and in the extending direction of the leg portions. It can also arrange | position apart in the direction which cross | intersects, for example, the orthogonal direction.

  Moreover, the form constructed | assembled combining embodiment and the said modification arbitrarily is also contained 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.

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

20 Electrode bodies 20b, 20c End portions (end portions of electrode bodies)
21 Positive electrode
21a Positive electrode current collecting tab 22 Negative electrode (electrode plate)
22a Negative electrode current collecting tabs 24a, 24b Flat wall-shaped parts (parts facing the electrode body, flat parts of the electrode body)
24c, 24d Curved wall portion (curved portion of electrode body)
26 Positive Current Collection Tab Group (Connector of Electrode Body)
27 Negative Current Collector Tab Group (Connector of Electrode Body)
50 Positive electrode current collector 52, 62 Leg 60 Negative electrode current collector 100 Storage element A Winding axis B Winding direction

Claims (7)

An electrical storage element comprising: an electrode body having a laminated electrode plate; and a current collector connected to an end of the electrode body in a direction intersecting a lamination direction of the electrode plate,
A power storage element in which one leg portion of the current collector is connected to each connection portion of an opposing portion of the end portion of the electrode body. The power storage device according to claim 1, wherein the plurality of connection portions are shifted in the extending direction of the leg portions. The electric storage element according to claim 1, wherein the connection portion is configured by a tab of the electrode body protruding in a direction intersecting with a stacking direction of the electrode plates. The electrode body includes the connecting portion of the positive electrode at one end of the electrode body in a direction intersecting with the stacking direction of the electrode plates, and the electrode body in a direction intersecting with the stacking direction of the electrode plates. The electrical storage element as described in any one of Claims 1-3 which contains the said connection part of a negative electrode in the edge part different from said one edge part. The electrical storage element according to any one of claims 1 to 4, wherein the electrode body is formed by winding the electrode plate. The power storage element according to claim 5, wherein the plurality of connection portions are arranged substantially evenly along a winding direction of the electrode body. The electrode body includes a flat portion facing each other, and a curved portion connecting the flat portions,
The power storage device according to claim 5 or 6, wherein the connection portion is located in the flat portions facing each other.

Images