Electrode group and battery

Abstract

To provide an electrode group that enables an increase in battery capacity without increasing the overall size.SOLUTION: A battery according to an embodiment includes a first electrode and a second electrode having an opposite polarity to the first electrode, and the first electrode includes a current collector and an active material-containing layer coated on the surface of the current collector. The active material-containing layer includes a layer edge that is an edge on one side in the length direction, and an inner edge extension is provided at the layer edge along a width direction intersecting the length direction, on the inner side in the length direction relative to the outer edge extension. The current collector of the first electrode includes a current collecting bundle portion in which only uncoated portions of the active material-containing layer are bundled, and the current collecting bundle portion is formed between the outer edge extension and the inner edge extension in the length direction.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] An embodiment of the present invention relates to an electrode group and a battery. [Background technology]

[0002] Some batteries, such as lithium ion secondary batteries, have an electrode group including a positive electrode and a negative electrode housed in the internal cavity of the exterior part. In such batteries, each of the positive electrode and the negative electrode of the electrode group includes a conductive current collector and an active material-containing layer coated on the surface of the current collector. In the battery, the battery capacity increases as the area where the active material-containing layer is coated on each current collector of the positive electrode and the negative electrode increases. Here, in the battery, it may be impossible to increase the external dimensions of the battery and the electrode group due to specifications, restrictions, etc. For this reason, it is required to increase the battery capacity by, for example, increasing the area where the active material-containing layer is coated on the current collector of either the positive electrode or the negative electrode of the electrode group without increasing the external dimensions of the battery and the electrode group. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. 2013 / 046349 [Patent Document 2] JP 2011-76787 A [Patent Document 3] JP 2011-49065 A [Patent Document 4] JP 2014-49193 A [Patent Document 5] JP 2013-122888 A Summary of the Invention [Problem to be solved by the invention]

[0004] An object of the present invention is to provide an electrode group and a battery that can increase the battery capacity without increasing the external dimensions. [Means for solving the problem]

[0005] According to the embodiment, the battery comprises a first electrode and a second electrode having a polarity opposite to that of the first electrode, the first electrode comprising a first conductive current collector and a first active material-containing layer coated on the surface of the first current collector. The first active material-containing layer comprises a first layer edge which is an edge on one side in the length direction, and the first layer edge comprises a first outer edge extension extending along a width direction intersecting the length direction, and a first inner edge extension extending along the width direction on the inner side in the length direction relative to the first outer edge extension. The first current collector comprises a first current collecting bundle part in which only the uncoated portion of the first active material-containing layer is bundled, and the first current collecting bundle part is formed between the first outer edge extension and the first inner edge extension in the length direction. [Brief description of the drawings]

[0006] [Figure 1] FIG. 1 is a perspective view that diagrammatically illustrates a battery according to a first embodiment. [Diagram 2] FIG. 2 is a schematic diagram showing a cross section of the battery according to the first embodiment, perpendicular or substantially perpendicular to the depth direction of the battery. [Diagram 3] FIG. 3 is a perspective view that diagrammatically illustrates an electrode group of the battery according to the first embodiment. [Figure 4] FIG. 4 is a schematic diagram showing the first electrode of the electrode group according to the first embodiment as viewed from the thickness direction of the electrode group. [Diagram 5] FIG. 5 is a schematic diagram showing the second electrode of the electrode group according to the first embodiment as viewed from the thickness direction of the electrode group. [Figure 6] FIG. 6 is a schematic diagram showing a separator in the electrode group according to the first embodiment as viewed from the thickness direction of the electrode group. [Figure 7] FIG. 7 is a schematic diagram showing the electrode group according to the first embodiment as viewed from the thickness direction of the electrode group. [Figure 8]FIG. 8 is a schematic cross-sectional view of the electrode group according to the first embodiment, taken along a line perpendicular or substantially perpendicular to the width direction of the electrode group and passing through a position separated in the width direction of the electrode group from both the current collecting bundle portion of the first electrode and the current collecting bundle portion of the second electrode. [Figure 9] FIG. 9 is a cross-sectional view that diagrammatically illustrates the electrode group according to the first embodiment, taken along a line perpendicular or substantially perpendicular to the width direction of the electrode group and passing through the current collecting bundle portion of the first electrode. [Figure 10] FIG. 10 is a cross-sectional view that diagrammatically illustrates the electrode group according to the first embodiment, taken along a line perpendicular or substantially perpendicular to the width direction of the electrode group and passing through the current collecting bundle portion of the second electrode. [Figure 11] FIG. 11 is a perspective view that illustrates a schematic view of any one of a pair of lead members in the battery according to the first embodiment. [Figure 12] FIG. 12 is a schematic view showing an example of a manufacturing process for the electrode plate of the first electrode and the electrode plate of the second electrode of the battery according to the first embodiment. [Figure 13] FIG. 13 is a perspective view that diagrammatically illustrates any one of a pair of lead members in a battery according to a first modified example of the first embodiment. [Figure 14] FIG. 14 is a perspective view that illustrates a schematic view of any one of a pair of lead members in a battery according to a second modified example of the first embodiment. [Figure 15] FIG. 15 is a perspective view that diagrammatically illustrates any one of a pair of lead members in a battery according to a third modified example of the first embodiment. [Figure 16] FIG. 16 is a schematic diagram showing an electrode group according to a fourth modified example of the first embodiment, as viewed in the thickness direction of the electrode group. [Figure 17] FIG. 17 is a schematic diagram showing an electrode group according to a fifth modified example of the first embodiment, as viewed in the thickness direction of the electrode group. [Figure 18] FIG. 18 is a schematic diagram showing a cross section of a battery according to a second embodiment, the cross section being perpendicular or substantially perpendicular to the depth direction of the battery. [Figure 19] FIG. 19 is a perspective view that illustrates a schematic configuration of an electrode group of a battery according to the second embodiment. [Figure 20] FIG. 20 is a schematic diagram showing a first electrode of an electrode group according to a second embodiment, as viewed from the thickness direction of the electrode group. [Figure 21] FIG. 21 is a schematic diagram showing a second electrode of an electrode group according to a second embodiment, as viewed from the thickness direction of the electrode group. [Figure 22] FIG. 22 is a schematic diagram showing a separator of an electrode group according to a second embodiment as viewed from the thickness direction of the electrode group. [Diagram 23] FIG. 23 is a schematic diagram showing the electrode group according to the second embodiment as viewed from the thickness direction of the electrode group. [Figure 24] FIG. 24 is a perspective view that illustrates a schematic view of any one of a pair of lead members in the battery according to the second embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0007] Hereinafter, an embodiment will be described with reference to the drawings.

[0008] (First embodiment) 1 and 2 show a battery 1 according to a first embodiment. As shown in FIG. 1 and FIG. 2, the battery 1 includes an electrode group 2 and an exterior part 3. In one example shown in FIG. 1 and FIG. 2, the exterior part 3 includes an exterior container 4 and a lid member 5. The exterior container 4 and the lid member 5 are each formed of a metal such as aluminum, an aluminum alloy, iron, copper, or stainless steel. Here, in the battery 1 (exterior part 3), a depth direction (direction indicated by arrows X1 and X2), a lateral direction (direction indicated by arrows Y1 and Y2) intersecting (perpendicular or substantially perpendicular) with respect to the depth direction, and a height direction (direction indicated by arrows Z1 and Z2) intersecting (perpendicular or substantially perpendicular) with respect to both the depth direction and the lateral direction are defined. In each of the battery 1 and exterior part 3 in one example shown in FIG. 1 and FIG. 2, the dimension in the depth direction is smaller than the dimension in the lateral direction and the dimension in the height direction. 1 is a schematic perspective view, and FIG. 2 is a schematic cross-sectional view perpendicular or substantially perpendicular to the depth direction.

[0009] The outer container 4 includes a bottom wall 6 and a peripheral wall 7. An internal cavity 8 in which the electrode group 2 is accommodated is formed inside the outer container 3. In one example such as FIG. 1 and FIG. 2, the internal cavity 8 is defined by the bottom wall 6 and the peripheral wall 7 of the outer container 4. In the outer container 4, the internal cavity 8 opens to the opposite side to the side where the bottom wall 6 is located in the height direction. The peripheral wall 7 includes two pairs of side walls 11, 12. The pair of side walls 11 face each other in the lateral direction with the internal cavity 8 therebetween. The pair of side walls 12 face each other in the depth direction with the internal cavity 8 therebetween. Each of the side walls 11 extends continuously between the side walls 12 along the depth direction. Each of the side walls 12 extends continuously between the side walls 11 along the lateral direction. The cover member 5 is attached to the peripheral wall 7 at the end opposite to the bottom wall 6. Therefore, the cover member 5 closes the opening of the internal cavity 8 of the outer container 4. The cover member 5 and the bottom wall 6 face each other in the height direction with the internal cavity 8 interposed therebetween.

[0010] The electrode group 2 includes a positive electrode and a negative electrode. In the electrode group, a separator is interposed between the positive electrode and the negative electrode. In the electrode group 2, the separator is made of an electrically insulating material and electrically insulates the positive electrode from the negative electrode.

[0011] In the electrode group 2, the positive electrode comprises a positive electrode current collector such as a positive electrode current collector foil, and a positive electrode active material-containing layer coated (carried) on the surface of the positive electrode current collector. The positive electrode current collector is, but is not limited to, for example, an aluminum foil or an aluminum alloy foil, and has a thickness of about 5 μm to 20 μm. The positive electrode active material-containing layer comprises a positive electrode active material, and may optionally contain a binder and a conductive agent. Examples of the positive electrode active material include, but are not limited to, oxides, sulfides, and polymers that can absorb and release lithium ions.

[0012] In the electrode group 2, the negative electrode comprises a negative electrode current collector such as a negative electrode current collector foil, and a negative electrode active material-containing layer (not shown) coated (supported) on the surface of the negative electrode current collector. The negative electrode current collector is, but is not limited to, for example, an aluminum foil, an aluminum alloy foil, or a copper foil, and has a thickness of about 5 μm to 20 μm. The negative electrode active material-containing layer comprises a negative electrode active material, and may optionally contain a binder and a conductive agent. The negative electrode active material is, but is not limited to, a metal oxide, a metal sulfide, a metal nitride, a carbon material, and the like that can absorb and release lithium ions.

[0013] In addition, in the internal cavity 8, the electrode group 2 is held (impregnated) with an electrolytic solution (not shown). The electrolytic solution may be an aqueous electrolytic solution such as an aqueous solution, or a non-aqueous electrolytic solution in which an electrolyte is dissolved in an organic solvent. Instead of the electrolytic solution, a gel electrolyte or a solid electrolyte may be used. When a solid electrolyte is used as the electrolyte, the separator in the electrode group 2 may be formed from the solid electrolyte.

[0014] Hereinafter, one of the positive and negative electrodes of the electrode group 2 is referred to as a first electrode 20A, and one of the positive and negative electrodes of the electrode group 2 having the opposite polarity to the first electrode 20A is referred to as a second electrode 20B. In the battery 1 of this embodiment, a pair of terminals 13 is attached to the cover member 5 of the exterior part 3. The terminals 13 are made of a conductive material such as metal. One of the pair of terminals 13 is a positive electrode terminal of the battery 1, and the other of the pair of terminals 13 is a negative electrode terminal of the battery 1. In the battery 1, one of the pair of terminals 13, a terminal (first terminal) 13A, is electrically connected to the first electrode 20A of the electrode group 2, and the other of the pair of terminals 13, a terminal (second terminal) 13B, is electrically connected to the second electrode 20B of the electrode group 2.

[0015] Each of the terminals 13 is attached to the lid member 5 of the exterior part 3 in a state where it is exposed to the outside of the battery 1. The pair of terminals 13 are arranged apart from each other in the lateral direction of the battery 1. Furthermore, on the outer surface of the lid member 5, an insulating member 15 is provided between each of the terminals 13 and the lid member 5. Each of the terminals 13 is electrically insulated from the exterior part 3 (outer container 4 and lid member 5) by the insulating member 15 etc.

[0016] A pair of lead members 16 are disposed in the internal cavity 8 of the exterior part 3. Each of the lead members 16 is formed from a conductive material such as a metal, and examples of materials for forming the lead members 16 include aluminum, stainless steel, copper, and iron. One of the pair of lead members 16 serves as a positive electrode side lead, and the other of the pair of lead members 16 other than the positive electrode side lead serves as a negative electrode side lead.

[0017] In the internal cavity 8, the first electrode 20A of the electrode group 2 is electrically connected to the terminal 13A through a lead member (first lead member) 16A, which is one of a pair of lead members 16. Therefore, the lead member 16A forms at least a part of the electrical path between the first electrode 20A and the terminal 13A. In addition, in the internal cavity 8, the second electrode 20B of the electrode group 2 is electrically connected to the terminal 13B through a lead member (second lead member) 16B, which is the other one of the pair of lead members 16 other than the lead member 16A. Therefore, the lead member 16B forms at least a part of the electrical path between the second electrode 20B and the terminal 13B. The pair of lead members 16 do not contact each other and are electrically insulated from each other. In this embodiment, the pair of lead members 16 are arranged apart from each other in the lateral direction of the battery 1.

[0018] Further, a spacer (electrode group holder) 17 is disposed in the internal cavity 8 of the exterior part 3. The spacer 17 is made of an electrically insulating material. The spacer 17 is disposed between the electrode group 2 and the lid member 5 in the height direction of the battery 1, and between each of the pair of lead members 16 and the lid member 5 in the height direction of the battery 1. In the internal cavity 8, the spacer 17 and the like prevent the current collectors of the first electrode 20A and the second electrode 20B and the pair of lead members 16 from contacting the exterior part 3 (the exterior container 4 and the lid member 5). Therefore, the current collectors of the first electrode 20A and the second electrode 20B and the lead members 16 are electrically insulated from the exterior part 3.

[0019] 1 and 2, in one example, a safety valve and a liquid inlet (neither of which are shown) may be formed in the lid member 5. In this case, a sealing plate (not shown) that closes the liquid inlet is welded to the outer surface of the lid member 5. The safety valve and the liquid inlet are disposed between the pair of terminals 13 in the lateral direction of the battery 1.

[0020] Fig. 3 is a perspective view showing the electrode group 2. As shown in Figs. 2 and 3, the electrode group 2 has a length direction (direction shown by arrows L1 and L2), a width direction (direction shown by arrows W1 and W2) that intersects (orthogonal or substantially orthogonal) with the length direction, and a thickness direction (direction shown by arrows T1 and T2) that intersects (orthogonal or substantially orthogonal) with both the length direction and the width direction. The electrode group 2 has a smaller dimension in the thickness direction than the dimension in the length direction and the dimension in the width direction. The electrode group 2 is formed in a flat shape.

[0021] As shown in FIG. 3 and other figures, in this embodiment, the electrode group 2 includes a plurality of electrode plates 21, and the electrode group 2 is formed in a stack structure in which the plurality of electrode plates 21 are stacked in the thickness direction of the electrode group 2. Therefore, the stacking direction of the electrode plates 21 coincides or approximately coincides with the thickness direction of the electrode group 2. The electrode group 2 includes, as the electrode plates 21, a plurality of electrode plates (first electrode plates) 21A and a plurality of electrode plates (second electrode plates) 21B. In the electrode group 2, the first electrode 20A is formed by the plurality of electrode plates 21A, and the second electrode 20B is formed by the plurality of electrode plates 21B. In the electrode group 2, the plurality of electrode plates 21A and the plurality of electrode plates 21B are alternately stacked in the thickness direction of the electrode group 2.

[0022] In the present embodiment, the electrode group 2 includes a plurality of separator sheets 23, and in the electrode group 2, the separator 22 is formed by the plurality of separator sheets 23. In the electrode group 2, a corresponding one of the separator sheets 23 is disposed between the electrode plates 21A and 21B adjacent to each other in the thickness direction (stacking direction of the electrode plates 21) of the electrode group 2. In the electrode group 2 of the example of FIG. 3, the outermost layer in the thickness direction (stacking direction of the electrode plates 21) of the electrode group 2 is formed by a corresponding one of the separator sheets 23. Each of the plurality of electrode plates 21 is disposed in a state where the plate thickness direction coincides or approximately coincides with the thickness direction of the electrode group 2, and each of the plurality of separator sheets 23 is disposed in a state where the sheet thickness direction coincides or approximately coincides with the thickness direction of the electrode group 2.

[0023] FIG. 4 is a schematic diagram showing a first electrode 20A formed from a stack of electrode plates (first electrode plates) 21A as viewed from the thickness direction of the electrode group 2. In FIG. 4, the first electrode 20A is shown as a projection from the thickness direction of the electrode group 2, and the second electrode 20B and the separator 22 are not shown. As shown in FIG. 4, each of the multiple electrode plates 21A constituting the first electrode 20A includes a conductive current collector (first current collector) 25A and an active material-containing layer (first active material-containing layer) 26A coated (carried) on the surface of the current collector 25A. The active material-containing layer 26A contains the active material of the first electrode 20A. In each current collector 25A of the electrode plate 21A, a pair of main surfaces facing opposite to each other in the plate thickness direction of the electrode plate 21A is defined. In each of the electrode plates 21A, the active material-containing layer 26A may be coated on both of the pair of main surfaces of the current collector 25A, or the active material-containing layer 26A may be coated on only one of the pair of main surfaces of the current collector 25A.

[0024] Each current collector 25A of the electrode plate 21A is formed with a current collector edge 27A which is an edge on one side in the length direction of the electrode group 2, and a current collector edge 28A which is an edge on the opposite side to the current collector edge 27A in the length direction of the electrode group 2. Each active material-containing layer 26A of the electrode plate 21A is formed with a layer edge (first layer edge) 31A which is an edge on one side in the length direction of the electrode group 2, and a layer edge 32A which is an edge on the opposite side to the layer edge 31A in the length direction of the electrode group 2. The layer edge 31A is composed of an outer edge extension portion 33A, an inner edge extension portion 35A, an edge relay portion 36A, and the like, as described later. In each active material-containing layer 26A of the electrode plate 21A, the layer edge 31A is an edge on the side where the current collector edge 27A is located in the length direction of the electrode group 2, and the layer edge 32A is an edge on the side where the current collector edge 28A is located in the length direction of the electrode group 2.

[0025] The current collector edge 28A and the layer edge 32A each extend along the width direction of the electrode group 2. In the example of FIG. 4, in each of the electrode plates 21A, the layer edge 32A is located slightly inside the current collector edge 28A in the length direction of the electrode group 2. However, in one example, in each of the electrode plates 21A, the active material-containing layer 26A may extend to the current collector edge 28A of the current collector 25A in the length direction of the electrode group 2. In this case, in the projection of the electrode group 2 from the thickness direction, the layer edge 32A of the active material-containing layer 26A overlaps with the current collector edge 28A of the current collector 25A.

[0026] In each of the active material-containing layers 26A of the first electrode 20A, the layer edge (first layer edge) 31A includes an outer edge extension portion (first outer edge extension portion) 33A and an inner edge extension portion (first inner edge extension portion) 35A. In each of the layer edges 31A of the active material-containing layers 26A, the outer edge extension portion 33A and the inner edge extension portion 35A each extend along the width direction of the electrode group 2.

[0027] Furthermore, in each layer edge 31A of the active material-containing layer 26A, the inner edge extension 35A is located inside the outer edge extension 33A in the longitudinal direction of the electrode group 2. Therefore, in each electrode plate 21A, the inner edge extension 35A is located closer to the current collector edge 28A of the current collector 25A and the layer edge 32A of the active material-containing layer 26A than the outer edge extension 33A. In each electrode plate 21A, the distance from the inner edge extension 35A to the current collector edge 27A of the current collector 25A is greater than the distance from the outer edge extension 33A to the current collector edge 27A.

[0028] 4, in each of the electrode plates 21A, the outer edge extension 33A of the layer edge 31A is located slightly inside the current collector edge 27A in the length direction of the electrode group 2. However, in one example, in each of the electrode plates 21A, the active material-containing layer 26A may be extended to the current collector edge 27A of the current collector 25A in the length direction of the electrode group 2. In this case, in the projection of the electrode group 2 from the thickness direction, the outer edge extension 33A of the layer edge 31A of the active material-containing layer 26A overlaps with the current collector edge 27A of the current collector 25A, and in each of the electrode plates 21A, the distance from the outer edge extension 33A to the current collector edge 27A is zero or approximately zero.

[0029] In each of the active material-containing layers 26A of the first electrode 20A, an edge relay portion (first edge relay portion) 36A that relays between the outer edge extension portion 33A and the inner edge extension portion 35A is formed on the layer edge 31A. In one example of FIG. 4, a pair of edge relay portions 36A1, 36A2 are formed as the edge relay portion 36A on each layer edge 31A of the active material-containing layer 26A. Each edge relay portion 36A extends along the length direction of the electrode group 2. In one example of FIG. 4, a concave shape that is concave from the outer edge extension portion 33A to the inside in the length direction of the electrode group 2 is formed by the inner edge extension portion 35A and the edge relay portion 36A on each layer edge 31A of the active material-containing layer 26A.

[0030] In each current collector 25A of the electrode plate 21A, an uncoated belt portion (first uncoated belt portion) 37A is formed in a portion where the inner edge extension portion 35A and the edge relay portions 36A1, 36A2 of the layer edge 31A are adjacent to each other. In each electrode plate 21A, the uncoated belt portion 37A is formed from a portion where the active material-containing layer 26A is not coated on both of the pair of main surfaces, that is, a portion where the active material-containing layer 26A is not coated. In each electrode plate 21A, the uncoated belt portion 37A is formed between the outer edge extension portion 33A and the inner edge extension portion 35A in the length direction of the electrode group 2. In the example of FIG. 4, in each electrode plate 21A, the uncoated belt portion 37A is formed between the pair of edge relay portions 36A1, 36A2 in the width direction of the electrode group 2.

[0031] In the first electrode 20A, a current collecting bundle portion (first current collecting bundle portion) 38A is formed by bundling the uncoated belt portions 37A of the current collectors 25A of the multiple electrode plates 21A. In the current collecting bundle portion 38A, only the portions of the current collectors 25A of the first electrode 20A that are not coated with the active material-containing layer 26A are bundled. In each of the electrode plates 21A, the uncoated belt portions 37A of the current collectors 25A are formed at the positions described above. Therefore, in the first electrode 20A, the current collecting bundle portion 38A is formed between the outer edge extension portion 33A and the inner edge extension portion 35A of the layer edge 31A of the active material-containing layer 26A in the longitudinal direction of the electrode group 2. That is, the current collecting bundle portion 38A is located inside the outer edge extension 33A of the layer edge 31A in the longitudinal direction of the electrode group 2, and is located outside the inner edge extension 35A of the layer edge 31A in the longitudinal direction of the electrode group 2.

[0032] In the first electrode 20A, the active material-containing layer 26A is adjacent to the current collecting bundle portion 38A from the inside in the length direction of the electrode group 2, with the inner edge extension portion 35A of the layer edge 31A as a boundary. In the first electrode 20A, the active material-containing layer 26A is adjacent to the current collecting bundle portion 38A from one side in the width direction of the electrode group 2, with the edge relay portion 36A1 of the layer edge 31A as a boundary. In the first electrode 20A, the active material-containing layer 26A is adjacent to the current collecting bundle portion 38A from the side opposite to the side where the edge relay portion 36A1 is located in the width direction of the electrode group 2, with the edge relay portion 36A2 of the layer edge 31A as a boundary. Therefore, in the example of FIG. 4, the active material-containing layer 26A is adjacent to the current collecting bundle portion 38A from both sides in the width direction of the electrode group 2, with the edge relay portions 36A1 and 36A2 of the layer edge 31A as boundaries.

[0033] Further, the first electrode 20A is formed with a notch (first notch) 40A that opens outward in the length direction of the electrode group 2. The notch 40A penetrates the first electrode 20A in the thickness direction of the electrode group 2 (stacking direction of the electrode plates 21), and penetrates each of the multiple electrode plates 21A that form the first electrode 20A in the plate thickness direction. Further, in the first electrode 20A, the notch 40A is formed at an end on the side where the current collector edge 27A of the current collector 25A and the layer edge 31A of the active material-containing layer 26A are located in the length direction of the electrode group 2. In the first electrode 20A, the active material-containing layer 26A is formed between the notch 40A and the current collector edge 28A of the current collector 25A in the length direction of the electrode group 2.

[0034] In the example of FIG. 4, the notch 40A of the first electrode 20A is not shifted or is hardly shifted with respect to the current collecting bundle portion 38A in the length direction of the electrode group 2. However, in the first electrode 20A, the notch 40A is located away from the current collecting bundle portion 38A in the width direction of the electrode group 2. The notch 40A is located away from the inner edge extension portion 35A and the edge relay portion 36A of the layer edge 31A in the width direction of the electrode group 2. In the projection of the electrode group 2 from the thickness direction, the notch 40A of the first electrode 20A is located at a position that does not overlap with the current collecting bundle portion 38A and is located away from the current collecting bundle portion 38A. In the first electrode 20A, a concave shape that is concave inward in the length direction of the electrode group 2 is formed by the notch 40A at each current collector edge 27A of the current collector 25A and each layer edge 31A of the active material-containing layer 26A. At each current collector edge 27A of current collector 25A, the portion other than notch 40A extends along the width direction of electrode group 2.

[0035] FIG. 5 is a schematic diagram showing a second electrode 20B formed from a stack of electrode plates (second electrode plates) 21B as viewed from the thickness direction of the electrode group 2. In FIG. 5, the second electrode 20B is shown as a projection from the thickness direction of the electrode group 2, and the first electrode 20A and the separator 22 are not shown. As shown in FIG. 5, each of the multiple electrode plates 21B constituting the second electrode 20B includes a conductive current collector (second current collector) 25B and an active material-containing layer (second active material-containing layer) 26B coated (carried) on the surface of the current collector 25B. The active material-containing layer 26B contains the active material of the second electrode 20B. In each current collector 25B of the electrode plate 21B, a pair of main surfaces is defined in the same manner as the current collector 25A. In each of the electrode plates 21B, the active material-containing layer 26B may be coated on both of the pair of main surfaces of the current collector 25B, or the active material-containing layer 26B may be coated on only one of the pair of main surfaces of the current collector 25B.

[0036] In each of the current collectors 25B of the electrode plate 21B, current collector edges 27B and 28B are formed as both edges in the length direction of the electrode group 2, similar to the current collector 25A. In each of the active material-containing layers 26B of the electrode plate 21B, layer edges (second layer edges) 31B and layer edges 32B are formed as both edges in the length direction of the electrode group 2, similar to the active material-containing layer 26A. As described later, the layer edge 31B is composed of an outer edge extension portion 33B, an inner edge extension portion 35B, an edge relay portion 36B, and the like. In each of the active material-containing layers 26B of the electrode plate 21B, the layer edge 31B is the edge on the side where the current collector edge 27B is located in the length direction of the electrode group 2, and the layer edge 32B is the edge on the side where the current collector edge 28B is located in the length direction of the electrode group 2.

[0037] The current collector edge 28B and the layer edge 32B each extend along the width direction of the electrode group 2. In the example of Fig. 5, in each electrode plate 21B, the layer edge 32B is located slightly inside the current collector edge 28B in the length direction of the electrode group 2. However, in one example, in each electrode plate 21B, the active material-containing layer 26B may extend to the current collector edge 28B of the current collector 25B in the length direction of the electrode group 2, and the layer edge 32B of the active material-containing layer 26B may overlap the current collector edge 28B of the current collector 25B in the projection of the electrode group 2 from the thickness direction.

[0038] In each of the active material-containing layers 26B of the second electrode 20B, the layer edge (second layer edge) 31B includes an outer edge extension portion (second outer edge extension portion) 33B and an inner edge extension portion (second inner edge extension portion) 35B. In each of the layer edges 31B of the active material-containing layers 26B, the outer edge extension portion 33B and the inner edge extension portion 35B each extend along the width direction of the electrode group 2.

[0039] Furthermore, in each layer edge 31B of the active material-containing layer 26B, the inner edge extension 35B is located inside the outer edge extension 33B in the longitudinal direction of the electrode group 2. Therefore, in each electrode plate 21B, the inner edge extension 35B is located closer to the current collector edge 28B of the current collector 25B and the layer edge 32B of the active material-containing layer 26B than the outer edge extension 33B. In each electrode plate 21B, the distance from the inner edge extension 35B to the current collector edge 27B of the current collector 25B is greater than the distance from the outer edge extension 33B to the current collector edge 27B.

[0040] 5, in each of the electrode plates 21B, the outer edge extension 33B of the layer edge 31B is located slightly inside the current collector edge 27B in the length direction of the electrode group 2. However, in one example, in each of the electrode plates 21B, the active material-containing layer 26B may be extended to the current collector edge 27B of the current collector 25B in the length direction of the electrode group 2. In this case, in the projection of the electrode group 2 from the thickness direction, the outer edge extension 33B of the layer edge 31B of the active material-containing layer 26B overlaps with the current collector edge 27B of the current collector 25B, and in each of the electrode plates 21B, the distance from the outer edge extension 33B to the current collector edge 27B is zero or approximately zero.

[0041] In each of the active material-containing layers 26B of the second electrode 20B, an edge relay portion (second edge relay portion) 36B that relays between the outer edge extension portion 33B and the inner edge extension portion 35B is formed on the layer edge 31B. In one example of FIG. 5, a pair of edge relay portions 36B1, 36B2 are formed as the edge relay portion 36B on each layer edge 31B of the active material-containing layer 26B. Each edge relay portion 36B extends along the length direction of the electrode group 2. In one example of FIG. 5, a concave shape that is concave from the outer edge extension portion 33B to the inside in the length direction of the electrode group 2 is formed by the inner edge extension portion 35B and the edge relay portion 36B on each layer edge 31B of the active material-containing layer 26B.

[0042] In each current collector 25B of the electrode plate 21B, an uncoated belt portion (second uncoated belt portion) 37B is formed in a portion where the inner edge extension portion 35B and the edge relay portions 36B1, 36B2 of the layer edge 31B are adjacent to each other. In each electrode plate 21B, the uncoated belt portion 37B is formed from a portion where the active material-containing layer 26B is not coated on both of the pair of main surfaces, that is, a portion where the active material-containing layer 26B is uncoated. In each electrode plate 21B, the uncoated belt portion 37B is formed between the outer edge extension portion 33B and the inner edge extension portion 35B in the length direction of the electrode group 2. In the example of FIG. 5, in each electrode plate 21B, the uncoated belt portion 37B is formed between the pair of edge relay portions 36B1, 36B2 in the width direction of the electrode group 2.

[0043] In the second electrode 20B, a current collecting bundle portion (second current collecting bundle portion) 38B is formed by bundling the uncoated belt portions 37B of the current collectors 25B of a plurality of electrode plates 21B. In the current collecting bundle portion 38B, only the portions of the current collectors 25B of the second electrode 20B that are not coated with the active material-containing layer 26B are bundled. In each of the electrode plates 21B, the uncoated belt portions 37A of the current collectors 25B are formed at the positions described above. Therefore, in the second electrode 20B, the current collecting bundle portion 38B is formed between the outer edge extension portion 33B and the inner edge extension portion 35B of the layer edge 31B of the active material-containing layer 26B in the longitudinal direction of the electrode group 2. That is, the current collecting bundle portion 38B is located inside the outer edge extension 33B of the layer edge 31B in the longitudinal direction of the electrode group 2, and is located outside the inner edge extension 35B of the layer edge 31B in the longitudinal direction of the electrode group 2.

[0044] In the second electrode 20B, the active material-containing layer 26B is adjacent to the current collecting bundle portion 38B from the inside in the length direction of the electrode group 2, with the inner edge extension portion 35B of the layer edge 31B as a boundary. In the second electrode 20B, the active material-containing layer 26B is adjacent to the current collecting bundle portion 38B from one side in the width direction of the electrode group 2, with the edge relay portion 36B1 of the layer edge 31B as a boundary. In the second electrode 20B, the active material-containing layer 26B is adjacent to the current collecting bundle portion 38B from the opposite side in the width direction of the electrode group 2 to the side where the edge relay portion 36B1 is located, with the edge relay portion 36B2 of the layer edge 31B as a boundary. Therefore, in the example of FIG. 5, the active material-containing layer 26B is adjacent to the current collecting bundle portion 38B from both sides in the width direction of the electrode group 2, with the edge relay portions 36B1 and 36B2 of the layer edge 31B as boundaries.

[0045] Further, the second electrode 20B is formed with a notch (second notch) 40B that opens outward in the length direction of the electrode group 2. The notch 40B penetrates the second electrode 20B in the thickness direction of the electrode group 2 (stacking direction of the electrode plates 21) and penetrates each of the multiple electrode plates 21B forming the second electrode 20B in the plate thickness direction. Further, in the second electrode 20B, the notch 40B is formed at an end on the side where the current collector edge 27B of the current collector 25B and the layer edge 31B of the active material-containing layer 26B are located in the length direction of the electrode group 2. In the second electrode 20B, the active material-containing layer 26B is formed between the notch 40B and the current collector edge 28B of the current collector 25B in the length direction of the electrode group 2.

[0046] In the example of FIG. 5, the notch 40B of the second electrode 20B is not shifted or is hardly shifted in the length direction of the electrode group 2 with respect to the current collecting bundle portion 38B. However, in the second electrode 20B, the notch 40B is located away from the current collecting bundle portion 38A in the width direction of the electrode group 2. The notch 40B is located away from the inner edge extension portion 35B and the edge relay portion 36B of the layer edge 31B in the width direction of the electrode group 2. In the projection of the electrode group 2 from the thickness direction, the notch 40B of the second electrode 20B is located at a position that does not overlap with the current collecting bundle portion 38B and is located away from the current collecting bundle portion 38B. In the second electrode 20B, a concave shape that is concave inward in the length direction of the electrode group 2 is formed by the notch 40B in each current collector edge 27B of the current collector 25B and each layer edge 31B of the active material-containing layer 26B. At each current collector edge 27B of current collector 25B, the portion other than notch 40B extends along the width direction of electrode group 2.

[0047] FIG. 6 is a schematic diagram of a separator 22 formed from a stack of separator sheets 23, viewed from the thickness direction of the electrode group 2. In FIG. 6, the separator 22 is shown projected from the thickness direction of the electrode group 2, and the first electrode 20A and the second electrode 20B are not shown. As shown in FIG. 6, each of the multiple separator sheets 23 constituting the separator 22 has sheet edges 41 and 42 formed as both edges in the length direction of the electrode group 2. In each of the separator sheets 23, the sheet edge 42 is an edge on the opposite side to the sheet edge 41 in the length direction of the electrode group 2. In the example of FIG. 6, in each of the separator sheets 23, the sheet edge 42 is extended along the width direction of the electrode group 2.

[0048] Further, a pair of separator notches 43A, 43B are formed in the separator 22, and each of the separator notches 43A, 43B opens outward in the longitudinal direction of the electrode group 2. Each of the separator notches 43A, 43B penetrates the separator 22 in the thickness direction of the electrode group 2 (stacking direction of the electrode plates 21), and penetrates each of the multiple separator sheets 23 forming the separator 22 in the sheet thickness direction. Further, in the example of the separator 22 in Fig. 6, each of the separator notches 43A, 43B is formed in the longitudinal direction of the electrode group 2 at the end on the side where the sheet edge 41 of the separator sheet 23 is located.

[0049] In the example of FIG. 6, in the separator 22, the pair of separator notches 43A, 43B are not shifted or are hardly shifted from each other in the length direction of the electrode group 2. However, the pair of separator notches 43A, 43B are located apart from each other in the width direction of the electrode group 2. In a projection of the electrode group 2 from the thickness direction, the separator notches 43A, 43B are located at positions where they do not overlap each other and are located apart from each other. Also, in the separator 22, a pair of recessed shapes each recessed inward in the length direction of the electrode group 2 is formed by the separator notches 43A, 43B at each sheet edge 41 of the separator sheet 23. At each sheet edge 41 of the separator sheet 23, a portion other than the notches 43A, 43B is extended along the width direction of the electrode group 2.

[0050] FIG. 7 shows the electrode group 2 in a schematic state as viewed from the thickness direction of the electrode group 2. That is, FIG. 7 shows the projection of the electrode group 2 from the thickness direction. FIG. 8 to FIG. 10 show cross sections of the electrode group 2 perpendicular or substantially perpendicular to the width direction. FIG. 8 shows a cross section passing through a position separated in the width direction of the electrode group 2 from both the current collecting bundle portion 38A of the first electrode 20A and the current collecting bundle portion 38B of the second electrode 20B. FIG. 9 shows a cross section passing through the current collecting bundle portion 38A of the first electrode 20A, and FIG. 10 shows a cross section passing through the current collecting bundle portion 38B of the second electrode 20B.

[0051] 3 to 10 etc., in the electrode group 2, the current collector edge 27B and layer edge 31B of the second electrode 20B are located on the side where the current collector edge 27A and layer edge 31A of the first electrode 20A are located, relative to the active material-containing layer 26A of the first electrode 20A and the active material-containing layer 26B of the second electrode 20B, in the length direction of the electrode group 2. In other words, the current collector edge 27B and layer edge 31B of the second electrode 20B are located on the opposite side to the side where the current collector edge 28A and layer edge 32A of the first electrode 20A are located, relative to the active material-containing layers 26A, 26B, in the length direction of the electrode group 2. For this reason, in the electrode group 2, the current collecting bundle portion 38B and notch 40B of the second electrode 20B are located on the side, relative to the active material-containing layers 26A, 26B, on which the current collecting bundle portion 38A and notch 40A of the first electrode 20A are located, in the longitudinal direction of the electrode group 2.

[0052] In the electrode group 2, the current collecting bundle portion 38B of the second electrode 20B is located away from the current collecting bundle portion 38A of the first electrode 20A in the width direction of the electrode group 2. Therefore, in the projection of the electrode group 2 from the thickness direction, the current collecting bundle portion 38B of the second electrode 20B is located at a position not overlapping with the current collecting bundle portion 38A of the first electrode 20A and is located away from the current collecting bundle portion 38A. Also, in the electrode group 2, the notch 40B of the second electrode 20B is located away from the notch 40A of the first electrode 20A in the width direction of the electrode group 2. Therefore, in the projection of the electrode group 2 from the thickness direction, the notch 40B of the second electrode 20B is located at a position not overlapping with the notch 40A of the first electrode 20A and is located away from the notch 40A. In addition, when a virtual central plane of the electrode group 2 in the width direction is defined, the current collecting bundle portions 38A, 38B may be arranged symmetrically (plane symmetrically) with respect to each other with respect to the aforementioned virtual central plane as the center, or they may not be arranged symmetrically (plane symmetrically) with respect to each other.

[0053] In the electrode group 2, the notch 40B of the second electrode 20B is not misaligned or is barely misaligned with the current collecting bundle portion 38A of the first electrode 20A in either the length direction or the width direction of the electrode group 2. Therefore, in a projection of the electrode group 2 from the thickness direction, the notch (second notch) 40B of the second electrode 20B is positioned so as to overlap with the current collecting bundle portion (first current collecting bundle portion) 38A of the first electrode 20A. In addition, in the electrode group 2, the notch 40A of the first electrode 20A is not misaligned or is barely misaligned with the current collecting bundle portion 38B of the second electrode 20B in either the length direction or the width direction of the electrode group 2. For this reason, in projection of the electrode group 2 from the thickness direction, the notch (first notch) 40A of the first electrode 20A is positioned so as to overlap with the current collecting bundle portion (second current collecting bundle portion) 38B of the second electrode 20B.

[0054] In the electrode group 2, the sheet edge 41 of the separator 22 is located on the side where the current collector edge 27A and layer edge 31A of the first electrode 20A and the current collector edge 27B and layer edge 31B of the second electrode 20B are located, relative to the active material-containing layer 26A of the first electrode 20A and the active material-containing layer 26B of the second electrode 20B, in the length direction of the electrode group 2. Therefore, in the electrode group 2, the separator notches 43A, 43B of the separator 22 are located on the side where the current collecting bundle portion 38A and notch 40A of the first electrode 20A and the current collecting bundle portion 38B and notch 40B of the second electrode 20B are located, relative to the active material-containing layers 26A, 26B, in the length direction of the electrode group 2.

[0055] In the electrode group 2, the separator notch 43A of the separator 22 is not misaligned or is barely misaligned with the current collecting bundle portion 38A of the first electrode 20A and the notch 40B of the second electrode 20B in either the length direction or the width direction of the electrode group 2. For this reason, in a projection of the electrode group 2 from the thickness direction, the separator notch (first separator notch) 43A of the separator 22 is positioned to overlap with the current collecting bundle portion (first current collecting bundle portion) 38A of the first electrode 20A and the notch (second notch) 40B of the second electrode 20B.

[0056] In the electrode group 2, the separator notch 43B of the separator 22 is not misaligned or is barely misaligned with respect to the current collecting bundle portion 38B of the second electrode 20B and the notch 40A of the first electrode 20A in either the length direction or the width direction of the electrode group 2. For this reason, in a projection of the electrode group 2 from the thickness direction, the separator notch (second separator notch) 43B of the separator 22 is positioned to overlap with the current collecting bundle portion (second current collecting bundle portion) 38B of the second electrode 20B and the notch (first notch) 40A of the first electrode 20A.

[0057] 2 and other figures, in this embodiment, the electrode group 2 is disposed in the internal cavity 8 with its length direction coinciding or approximately coinciding with the height direction of the battery 1. In addition, in the electrode group 2 disposed in the internal cavity 8, its width direction coincides or approximately coinciding with the lateral direction of the battery 1, and its thickness direction coincides or approximately coinciding with the depth direction of the battery 1.

[0058] In the internal cavity 8, the current collecting bundle portion 38A of the first electrode 20A and the current collecting bundle portion 38B of the second electrode 20B are located on the side where the lid member 5 is located with respect to the active material-containing layers 26A and 26B in the height direction of the battery 1, and are located on the opposite side to the side where the bottom wall 6 is located. Therefore, the notch 40A of the first electrode 20A, the notch 40B of the second electrode 20B, and the separator notches 43A and 43B of the separator 22 are located on the side where the lid member 5 is located with respect to the active material-containing layers 26A and 26B in the height direction of the battery 1. In the electrode group 2 arranged in the internal cavity 8, the current collecting bundle portion 38B of the second electrode 20B is located apart from the current collecting bundle portion 38A of the first electrode 20A in the lateral direction of the battery 1.

[0059] Since the electrode group 2 is accommodated in the internal cavity 8 as described above, in each layer edge 31A of the active material-containing layer 26A of the first electrode 20A, the outer edge extension 33A and the inner edge extension 35A each extend along the lateral direction of the battery 1, and the edge relay portion 36A extends along the height direction of the battery 1. In each layer edge 31A of the active material-containing layer 26A, the inner edge extension 35A is located on the opposite side of the outer edge extension 33A to the side on which the lid member 5 is located in the height direction of the battery 1. In the first electrode 20A, the current collecting bundle portion 38A is formed between the outer edge extension 33A and the inner edge extension 35A in the height direction of the battery 1.

[0060] Similarly, in each layer edge 31B of the active material-containing layer 26B of the second electrode 20B, the outer edge extension portion 33B and the inner edge extension portion 35B each extend along the lateral direction of the battery 1, and the edge relay portion 36B extends along the height direction of the battery 1. In each layer edge 31B of the active material-containing layer 26B, the inner edge extension portion 35B is located on the opposite side to the side on which the lid member 5 is located with respect to the outer edge extension portion 33B in the height direction of the battery 1. In the second electrode 20B, the current collecting bundle portion 38B is formed between the outer edge extension portion 33B and the inner edge extension portion 35B in the height direction of the battery 1.

[0061] FIG. 11 is a schematic perspective view of any one of the pair of lead members 16. As shown in FIG. 2 and FIG. 11, each of the lead members 16 includes a top plate portion 51 serving as an extended plate portion, and a joint plate portion 52. In one example, each of the lead members 16 is formed by bending a plate member, and in another example, each of the lead members 16 is formed by casting using a mold. In yet another example, each of the lead members 16 is formed by solid-state bonding or fastening a plurality of plate members with bolts. In each of the lead members 16, the joint plate portion 52 is formed to an appropriate plate thickness and outer shape, etc., within a range in which the bondability and electrical characteristics are ensured and the reliability as a component of the battery 1 is ensured.

[0062] In this embodiment, each top plate portion 51 of the lead member 16 is disposed between the electrode group 2 and the lid member 5 in the height direction of the battery 1, and between the electrode group 2 and the spacer 17. In the internal cavity 8, each top plate portion 51 of the lead member 16 is adjacent to the electrode group 2 from the outer side in the length direction of the electrode group 2, and adjacent to the electrode group 2 from the side where the lid member 5 is located in the height direction of the battery 1. In the internal cavity 8, each top plate portion 51 of the lead member 16 is disposed with the plate thickness direction coinciding or approximately coinciding with the height direction of the battery 1. The top plate portion 51 extends along the width direction of the electrode group 2 (the lateral direction of the battery 1).

[0063] 2 and 11, each top plate portion 51 of the lead member 16 is located outside the outer edge extension portion 33A of the layer edge 31A of the first electrode 20A and the outer edge extension portion 33B of the layer edge 31B of the second electrode 20B in the longitudinal direction of the electrode group 2. Each top plate portion 51 of the lead member 16 is located on the side where the lid member 5 is located, in the height direction of the battery 1, relative to the outer edge extension portion 33A of the first electrode 20A and the outer edge extension portion 33B of the second electrode 20B.

[0064] Further, each of the lead members 16 has a through hole 53 formed therein, which penetrates the top plate portion 51 in the plate thickness direction (height direction of the battery 1). In each of the lead members 16, a corresponding one of the pair of terminals 13 is inserted into the through hole 53, and the corresponding one of the pair of terminals 13 is connected to the top plate portion 51 at the through hole 53. In each of the top plate portions 51 of the lead members 16, a corresponding one of the terminals 13 is connected by crimping, welding, or the like. In the lead member (first lead member) 16A, the terminal (first terminal) 13A is connected to the top plate portion 51 at the through hole 53, and in the lead member (second lead member) 16B, the terminal (second terminal) 13B is connected to the top plate portion 51 at the through hole 53. In one example, instead of the through hole 53, a connection structure such as a protrusion is provided on each of the top plate portions 51 of the lead members 16, and a hole is formed in each of the terminals 13. In this case, each of the pair of lead members 16 is connected to one of the corresponding terminals 13 with the connection structure portion inserted into the corresponding hole of the terminal 13. The respective engagement structure portions of the lead members 16 are connected to the corresponding one of the terminals 13 by crimping, welding, or the like.

[0065] Each of the joint plate portions 52 of the lead member 16 protrudes from the top plate portion 51, which is an extended plate portion, toward the inside in the length direction of the electrode group 2. In this embodiment, each of the joint plate portions 52 of the lead member 16 protrudes from the top plate portion 51 toward the side where the bottom wall 6 is located in the height direction of the battery 1. In the internal cavity 8, each of the joint plate portions 52 of the lead member 16 is arranged with the plate thickness direction coinciding or approximately coinciding with the depth direction of the battery 1. Note that, in the example of the lead member 16 shown in FIG. 11, the cross section is T-shaped or approximately T-shaped in a cross section that is parallel or approximately parallel to both the plate thickness direction of the top plate portion 51 and the plate thickness direction of the joint plate portion 52 and passes through the joint plate portion 52. That is, in a cross section that is perpendicular or approximately perpendicular to the width direction of the electrode group 2 and passes through the joint plate portion 52, each of the lead members 16 has a T-shaped or approximately T-shaped cross section.

[0066] In each of the lead members 16, the joint plate portion 52 is joined to the corresponding one of the current collecting bundle portion 38A of the first electrode 20A and the current collecting bundle portion 38B of the second electrode 20B by welding or the like. Therefore, in the lead member 16A, the joint plate portion 52 is joined to the current collecting bundle portion 38A of the first electrode 20A, and in the lead member 16B, the joint plate portion 52 is joined to the current collecting bundle portion 38B of the second electrode 20B. In each of the joint plate portions 52 of the lead members 16, a pair of plate surfaces 55, 56 facing opposite sides to each other in the plate thickness direction are defined. In the example of FIG. 11, in each of the lead members 16, one of the pair of plate surfaces 55, 56 becomes a joint surface with the corresponding one of the current collecting bundle portions 38A, 38B.

[0067] The electrode group 2 having the above-mentioned configuration is formed as follows. Fig. 12 shows an example of a manufacturing process of the electrode plate 21A of the first electrode 20A and the electrode plate 21B of the second electrode 20B. As shown in Fig. 12, in forming the electrode plate 21A, a film 61 is attached to the surface of the current collector 25A, and the electrode plate 21A is masked. Then, a slurry that will become the active material-containing layer 26A is applied to the surface of the current collector 25A. At this time, the slurry is applied onto the film 61 in the portion where the film 61 is attached, and the slurry is not directly applied to the surface of the current collector 25A.

[0068] Then, the current collector 25A is cut to form both edges of the current collector 25A in the length direction of the electrode group 2, including the current collector edge 27A. The film 61 is also peeled off from the current collector 25A. Here, the slurry is not directly applied to the surface of the current collector 25A where the film 61 was attached, so that a portion where the active material-containing layer 26A is not coated is formed by peeling off the film 61. In the example of FIG. 12, a pair of uncoated belt portions 62A, 63A are formed as uncoated portions where the active material-containing layer 26A is not coated on both of the pair of main surfaces by peeling off the film 61 from the current collector 25A. The uncoated belt portions 62A, 63A are formed at positions separated from each other. In each of the uncoated belt portions 62A, 63A, the layer edge 31A of the active material-containing layer 26A is recessed inward.

[0069] In the electrode plate 21A of the first electrode 20A, the uncoated belt portion 62A formed as described above becomes the uncoated belt portion 37A constituting the current collecting bundle portion 38A of the electrode group 2. In addition, in forming the electrode plate 21A, a punching process is performed to cut out the uncoated belt portion 63A. The notch 65A is formed by cutting out the uncoated belt portion 63A. In the first electrode 20A, the notches 40A described above are formed by the notches 65A of the multiple electrode plates 21A.

[0070] In forming electrode plate 21B, similarly to forming electrode plate 21A, a film 61 is attached to the surface of current collector 25B, and a slurry to become active material-containing layer 26B is applied to the surface of current collector 25B. Then, by peeling film 61 from current collector 25B, a pair of uncoated belt portions 62B, 63B are formed as uncoated portions where active material-containing layer 26B is not coated on either of the pair of main surfaces, similarly to forming uncoated belt portions 62A, 63A in forming electrode plate 21A. Uncoated belt portions 62B, 63B are formed at positions spaced apart from each other.

[0071] In the electrode plate 21B of the second electrode 20B, the uncoated belt portion 63B formed as described above becomes the uncoated belt portion 37B constituting the current collecting bundle portion 38B of the electrode group 2. In addition, in forming the electrode plate 21B, a punching process is performed to cut out the uncoated belt portion 62B. By cutting out the uncoated belt portion 62B, a notch 65B is formed. In the second electrode 20B, the notches 40B described above are formed by the notches 65B of the multiple electrode plates 21B.

[0072] In addition, when forming separator sheet 23, two notches are formed by punching. One of the two notches formed in separator sheet 23 constitutes a part of separator notch 43A in separator 22, and the other of the two notches formed in separator sheet 23 constitutes a part of separator notch 43B in separator 22.

[0073] In one example, a long current collector having a large longitudinal dimension is transported, for example, by a roll-to-roll method, and the processes of attaching a film to the long current collector, coating the active material-containing layer 26A, peeling off the film, and punching are sequentially performed on the long current collector as described above. Then, the long current collector that has been coated with the active material-containing layer 26A and punched is cut or otherwise divided into a plurality of plate members in the longitudinal direction to form a plurality of electrode plates 21A.

[0074] As in the manufacture of electrode plate 21A, electrode plate 21B may be manufactured by dividing a long current collector that has been subjected to coating of active material-containing layer 26B, punching, or the like, into a plurality of plate members in the longitudinal direction, for example by cutting the long current collector, to form a plurality of electrode plates 21B. Similarly, separator sheet 23 may be manufactured by dividing a long sheet that has been subjected to punching, or the like, into a plurality of sheets in the longitudinal direction, for example by cutting the long sheet, to form a plurality of separator sheets 23.

[0075] After the electrode plates 21A, 21B and the separator sheet 23 are formed as described above, the electrode plates 21A, 21B are alternately stacked with the separator sheet 23 interposed between the electrode plates 21A, 21B. Then, the uncoated belt portions 37A of the multiple electrode plates 21A are bundled together to form the current collecting bundle portion 38A of the first electrode 20A, and the uncoated belt portions 37B of the multiple electrode plates 21B are bundled together to form the current collecting bundle portion 38B of the second electrode 20B. In this manner, the electrode group 2 is manufactured.

[0076] As described above, in the electrode group 2 of this embodiment, the active material-containing layer 26A of the first electrode 20A has a layer edge (first layer edge) 31A that is an edge on one side in the length direction, and in the layer edge 31A, the inner edge extension 35A is formed inside in the length direction with respect to the outer edge extension 33A. The current collector 25A of the first electrode 20A has a current collecting bundle part (first current collecting bundle part) 38A in which only the uncoated part of the active material-containing layer 26A is bundled, and the current collecting bundle part 38A is formed between the outer edge extension 33A and the inner edge extension 35A in the length direction. For this reason, in this embodiment, the current collecting bundle part 38A to which the lead member 16 is joined in the first electrode 20A is formed inside in the length direction of the electrode group 2 with respect to the outer edge extension 33A of the layer edge 31A of the active material-containing layer 26A.

[0077] Here, a configuration in which the current collecting bundle portion to which the lead member is joined in the first electrode protrudes from the layer edge of the active material-containing layer to the outside in the longitudinal direction of the electrode group is defined as the configuration of the comparative example. In this embodiment, the current collecting bundle portion 38A is formed inside the longitudinal direction of the electrode group 2 with respect to the outer edge extension portion 33A of the layer edge 31A, so that it is possible to increase the area where the active material-containing layer 26A is applied to the current collector 25A while maintaining the outer dimensions and volume, etc. of the electrode group 2, as compared with the configuration of the comparative example. Therefore, in this embodiment, it is possible to increase the battery capacity of the battery 1 without increasing the outer dimensions and volume, etc. of the electrode group 2 and the battery 1.

[0078] In this embodiment, the edge relay portion 36A relays between the outer edge extension portion 33A and the inner edge extension portion 35A at the layer edge 31A of the active material-containing layer 26A of the first electrode 20A. The active material-containing layer 26A is adjacent to the current collecting bundle portion 38A from the inside in the length direction of the electrode group 2, with the inner edge extension portion 35A as the boundary, and is adjacent to the current collecting bundle portion 38A from the width direction of the electrode group 2, with the edge relay portion 36A as the boundary. This appropriately realizes a configuration in which the current collecting bundle portion 38A is located inside the outer edge extension portion 33A of the layer edge 31A in the length direction of the electrode group 2.

[0079] In the electrode group 2 of this embodiment, the active material-containing layer 26B of the second electrode 20B has a layer edge (second layer edge) 31B that is an edge on one side in the length direction, and in the layer edge 31B, an inner edge extension 35B is formed inside in the length direction with respect to the outer edge extension 33B. The current collector 25B of the second electrode 20B has a current collecting bundle part (second current collecting bundle part) 38B in which only the uncoated part of the active material-containing layer 26B is bundled, and the current collecting bundle part 38B is formed between the outer edge extension part 33B and the inner edge extension part 35B in the length direction. For this reason, in this embodiment, the current collecting bundle part 38B to which the lead member 16 is joined in the second electrode 20B is formed inside in the length direction of the electrode group 2 with respect to the outer edge extension part 33B of the layer edge 31B of the active material-containing layer 26B.

[0080] Here, a configuration in which the current collecting bundle portion to which the lead member is joined in the second electrode protrudes from the layer end of the active material-containing layer to the outside in the longitudinal direction of the electrode group is defined as the configuration of the comparative example. In this embodiment, the current collecting bundle portion 38B is formed on the inside in the longitudinal direction of the electrode group 2 with respect to the outer edge extension portion 33B of the layer edge 31B, so that it is possible to increase the area where the active material-containing layer 26B is applied to the current collector 25B while maintaining the outer dimensions and volume of the electrode group 2, as compared with the configuration of the comparative example.

[0081] As described above, in this embodiment, it is possible to increase both the area where the active material-containing layer 26A is applied to the current collector 25A and the area where the active material-containing layer 26B is applied to the current collector 25B, without increasing the external dimensions, volume, etc., of the electrode group 2 and the battery 1. This makes it possible to further increase the battery capacity of the battery 1 without increasing the external dimensions, volume, etc. of the electrode group 2 and the battery 1.

[0082] In this embodiment, at the layer edge 31B of the active material-containing layer 26B of the second electrode 20B, an edge relay portion 36B relays between the outer edge extension portion 33B and the inner edge extension portion 35B. The active material-containing layer 26B is adjacent to the current collecting bundle portion 38B from the inside in the length direction of the electrode group 2, with the inner edge extension portion 35B as the boundary, and is adjacent to the current collecting bundle portion 38B from the width direction of the electrode group 2, with the edge relay portion 36B as the boundary. This appropriately realizes a configuration in which the current collecting bundle portion 38B is located inside the outer edge extension portion 33B of the layer edge 31B in the length direction of the electrode group 2.

[0083] In this embodiment, a notch (second notch) 40B is formed in the second electrode 20B, which penetrates the second electrode 20B in the thickness direction of the electrode group 2 and opens outward in the length direction of the electrode group 2. When projected in the thickness direction of the electrode group 2, the notch 40B of the second electrode 20B overlaps with the current collecting bundle portion (first current collecting bundle portion) 38A of the first electrode 20A. This appropriately prevents the current collecting bundle portion 38A of the first electrode 20A from contacting the second electrode 20B, and suppresses the occurrence of a short circuit between the first electrode 20A and the second electrode 20B caused by the current collecting bundle portion 38A contacting the second electrode 20B.

[0084] In this embodiment, a separator notch (first separator notch) 43A that penetrates the separator 22 in the thickness direction of the electrode group 2 and opens outward in the length direction of the electrode group 2 is formed in the separator 22. When projected in the thickness direction of the electrode group 2, the separator notch 43A overlaps with the current collecting bundle portion (first current collecting bundle portion) 38A of the first electrode 20A and the notch 40B of the second electrode 20B. This allows the multiple uncoated belt portions 37A to be appropriately bundled in the current collecting bundle portion 38A of the first electrode 20A.

[0085] In this embodiment, a notch (first notch) 40A that penetrates the first electrode 20A in the thickness direction of the electrode group 2 and opens outward in the length direction of the electrode group 2 is formed in the first electrode 20A. When projected in the thickness direction of the electrode group 2, the notch 40A of the first electrode 20A overlaps with the current collecting bundle portion (second current collecting bundle portion) 38B of the second electrode 20B. This appropriately prevents the current collecting bundle portion 38B of the second electrode 20B from contacting the first electrode 20A, and suppresses the occurrence of a short circuit between the first electrode 20A and the second electrode 20B caused by the current collecting bundle portion 38B contacting the first electrode 20A.

[0086] In this embodiment, a separator notch (second separator notch) 43B that penetrates the separator 22 in the thickness direction of the electrode group 2 and opens outward in the length direction of the electrode group 2 is formed in the separator 22. When projected in the thickness direction of the electrode group 2, the separator notch 43B overlaps with the current collecting bundle portion (second current collecting bundle portion) 38B of the second electrode 20B and the notch 40A of the first electrode 20A. This allows the multiple uncoated belt portions 37B to be appropriately bundled in the current collecting bundle portion 38B of the second electrode 20B.

[0087] In the battery 1 of this embodiment, in each of the pair of lead members 16, the top plate portion 51 serving as the extended plate portion is located outside the outer edge extended portion 33A of the layer edge 31A and the outer edge extended portion 33B of the layer edge 31B in the longitudinal direction of the electrode group 2. In each of the lead members 16, the joint plate portion 52 protrudes from the top plate portion 51 inward in the longitudinal direction of the electrode group 2. By configuring each of the lead members 16 in this way, even if the current collecting bundle portions 38A and 38B are formed in the electrode group 2 as described above, the joint plate portion 52 of the lead member 16A is appropriately joined to the current collecting bundle portion 38A of the first electrode 20A, and the joint plate portion 52 of the lead member 16B is appropriately joined to the current collecting bundle portion 38B of the second electrode 20B.

[0088] In this embodiment, in each of the lead members 16, the dimension of the top plate portion 51 along the depth direction of the exterior part 3 (thickness direction of the electrode group 2), i.e., the plate width of the top plate portion 51, is made the same or approximately the same as the dimension of the electrode group 2 along the thickness direction, so that the dimension of the top plate portion 51 along the depth direction of the exterior part 3 is increased. In each of the lead members 16, the dimension of the top plate portion 51 along the depth direction of the exterior part 3 is increased, so that even if the dimension of the top plate portion 51 along the height direction of the exterior part 3, i.e., the plate thickness of the top plate portion 51, is reduced, the cross-sectional area of ​​the top plate portion 51 is ensured to a certain degree. As a result, even if the dimension of the top plate portion 51 along the height direction of the exterior part 3 is reduced, the electrical resistance is prevented from increasing beyond a reference level. In addition, in each of the lead members 16, the dimension of the top plate portion 51 along the height direction of the exterior part 3 is reduced, so that the dimension of the electrode group 2 along the length direction of the electrode group 2 (height direction of the exterior part 3) can be increased. By increasing the dimension of the electrode group 2 along the longitudinal direction of the electrode group 2, the area where the active material-containing layer 26A is applied to the current collector 25A and the area where the active material-containing layer 26B is applied to the current collector 25B are further increased.

[0089] (Modification of the first embodiment) The shapes of the lead members 16 are not limited to those in the above-described embodiment. In a first modified example shown in Fig. 13, the cross section of the lead members 16 is L-shaped or approximately L-shaped in a cross section that is parallel or approximately parallel to both the plate thickness direction of the top plate 51 and the plate thickness direction of the bonding plate 52 and passes through the bonding plate 52. Therefore, the cross section of the lead members 16 is L-shaped or approximately L-shaped in a cross section that is perpendicular or approximately perpendicular to the width direction of the electrode group 2 and passes through the bonding plate 52.

[0090] In the above embodiment, only one current collecting bundle portion 38A of the first electrode 20A and one current collecting bundle portion 38B of the second electrode 20B are formed. However, in a modified example, a plurality of current collecting bundle portions 38A, 38B may be formed. In this modified example, the plurality of current collecting bundle portions 38A are formed shifted relative to each other in the thickness direction of the electrode group 2, and the plurality of current collecting bundle portions 38B are formed shifted relative to each other in the thickness direction of the electrode group 2.

[0091] In one modified example, two current collecting bundle parts 38A and two current collecting bundle parts 38B are formed. In the lead member 16A, two current collecting bundle parts 38A are joined to one joint plate part 52, and in the lead member 16B, two current collecting bundle parts 38B are joined to one joint plate part 52. In this modified example, in the joint plate part 52 of the lead member 16A, the plate surface 55 is a joint surface with one of the two current collecting bundle parts 38A, and the plate surface 56 is a joint surface with the other of the two current collecting bundle parts 38A. In the joint plate part 52 of the lead member 16B, the plate surface 55 is a joint surface with one of the two current collecting bundle parts 38B, and the plate surface 56 is a joint surface with the other of the two current collecting bundle parts 38B.

[0092] Further, the number of bonding plate portions 52 provided on the lead member 16 is not limited to one, and each of the lead members 16 may include a plurality of bonding plate portions 52. In a second modified example shown in FIG. 14, one lead member 16 includes two bonding plate portions 52α, 52β. In the battery 1 of this modified example, in each of the pair of lead members 16, the top plate portion 51 serving as the extended plate portion is positioned outside the outer edge extended portion 33A of the layer edge 31A and the outer edge extended portion 33B of the layer edge 31B in the longitudinal direction of the electrode group 2. In each of the lead members 16, each of the bonding plate portions 52α, 52β protrudes from the top plate portion 51 toward the inside in the longitudinal direction of the electrode group 2.

[0093] In this modification, in each of the lead members 16, the bonding plate portions 52α and 52β are positioned offset from each other in the thickness direction of the electrode group 2. In this modification, two current collecting bundle portions 38A and two current collecting bundle portions 38B are formed. In the lead member 16A, one of the two current collecting bundle portions 38A is bonded to the bonding plate portion 52α, and the other of the two current collecting bundle portions 38A is bonded to the bonding plate portion 52β. In the lead member 16B, one of the two current collecting bundle portions 38B is bonded to the bonding plate portion 52α, and the other of the two current collecting bundle portions 38B is bonded to the bonding plate portion 52β.

[0094] In this modification, the cross section of the lead member 16 is U-shaped or approximately U-shaped in a cross section that is parallel or approximately parallel to both the plate thickness direction of the top plate 51 and the plate thickness direction of the bonding plate portions 52α and 52β and passes through both the bonding plate portions 52α and 52β. Therefore, in a cross section that is perpendicular or approximately perpendicular to the width direction of the electrode group 2 and passes through both the bonding plate portions 52α and 52β, the cross section of each of the lead members 16 is U-shaped or approximately U-shaped. In this modification, the two bonding plate portions 52α and 52β in each of the lead members 16 are not misaligned or are barely misaligned with each other in the width direction of the electrode group 2.

[0095] In a third modified example shown in FIG. 15, similar to the modified example of FIG. 14, one lead member 16 includes two bonding plate portions 52α, 52β. Similarly to the modified example of FIG. 14, in the lead member 16A, each of the two current collecting bundle portions 38A is bonded to a corresponding one of the bonding plate portions 52α, 52β, and in the lead member 16B, each of the two current collecting bundle portions 38B is bonded to a corresponding one of the bonding plate portions 52α, 52β. However, unlike the modified example of FIG. 14, in each of the lead members 16, the two bonding plate portions 52α, 52β are arranged to be shifted from each other in the width direction of the electrode group 2. The two current collecting bundle portions 38A are formed to be shifted from each other in the width direction of the electrode group 2, and the two current collecting bundle portions 38B are formed to be shifted from each other in the width direction of the electrode group 2.

[0096] Any of the above-described modified examples, including the first to third modified examples, provides the same functions and effects as the first embodiment, etc. That is, as with any of the above-described modified examples, even if the configuration of the lead member 16, etc. is changed, it is possible to increase the battery capacity of the battery 1 without increasing the external dimensions, volume, etc. of the electrode group 2 and the battery 1.

[0097] 14 and the third modified example of Fig. 15, even if the number of electrode plates 21 (21A, 21B) stacked in the electrode group 2 is increased, many uncoated belt portions 37A can be divided into multiple current collecting bundle portions 38A and joined to the lead member 16A, and many uncoated belt portions 37B can be divided into multiple current collecting bundle portions 38B and joined to the lead member 16B. Therefore, even if the number of electrode plates 21 (21A, 21B) stacked in the electrode group 2 is increased, each of the current collecting bundle portions 38A, 38B can be easily joined to a corresponding one of the lead members 16, and the productivity of the battery 1 is ensured.

[0098] In addition, since a plurality of each of the current collecting bundle parts 38A and 38B are formed, even if the number of electrode plates 21 (21A, 21B) stacked in the electrode group 2 is increased, the increase in the number of uncoated belt parts 37A bundled in each of the current collecting bundle parts 38A is suppressed, and the increase in the number of uncoated belt parts 37B bundled in each of the current collecting bundle parts 38B is suppressed. Therefore, in each of the current collecting bundle parts 38A, the tension acting on the current collector 25A is reduced, making the current collector 25A less likely to be damaged. Similarly, in each of the current collecting bundle parts 38B, the tension acting on the current collector 25B is reduced, making the current collector 25B less likely to be damaged. Therefore, the joint strength of each of the current collecting bundle parts 38A and 38B is ensured, and the reliability of the battery 1 is ensured.

[0099] 15, in each of the lead members 16, the two bonding plate portions 52α, 52β are offset from each other in the width direction of the electrode group 2. This effectively prevents a tool or the like used for bonding, in the operation of bonding each of the current collecting bundle portions 38A, 38B to a corresponding one of the lead members 16, from interfering with the lead member 16. This eliminates the need to use a special tool, such as a tool for inverting and bonding objects to be bonded, in the operation of bonding each of the current collecting bundle portions 38A, 38B to a corresponding one of the lead members 16, and improves the productivity of the battery 1.

[0100] In a fourth modified example shown in Fig. 16, a slit (first slit) 66A is formed in the first electrode 20A, and a slit (second slit) 66B is formed in the second electrode 20B in the electrode group 2. Fig. 16 shows the electrode group 2 in a schematic manner as viewed from the thickness direction of the electrode group 2. That is, Fig. 16 shows a projection of the electrode group 2 from the thickness direction. In the first electrode 20A, the slits 66A are formed between the edge relay portion 36A of the layer edge 31A of the active material-containing layer 26A and the current collecting bundle portion 38A in the width direction of the electrode group 2. In the example of Fig. 16, a pair of slits 66A are formed in the first electrode 20A. One of the pair of slits 66A is formed between the edge relay portion 36A1 and the current collecting bundle portion 38A, and the other of the pair of slits 66A is formed between the edge relay portion 36A2 and the current collecting bundle portion 38A.

[0101] The slits 66A penetrate the first electrode 20A in the thickness direction of the electrode group 2. In each of the electrode plates 21A, the slits 66A penetrate the current collector 25A in the plate thickness direction. Each of the slits 66A extends along the length direction of the electrode group 2. Each of the slits 66A extends outward in the length direction of the electrode group 2 to the current collector edge 27A of the current collector 25A of the electrode plate 21A. In addition, the slits 66A are formed outward in the length direction of the electrode group 2 with respect to the inner edge extension portion 35A of the layer edge 31A of the active material-containing layer 26A.

[0102] In the second electrode 20B, the slits 66B are formed between the edge relay portion 36B of the layer edge 31B of the active material-containing layer 26B and the current collecting bundle portion 38B in the width direction of the electrode group 2. In the example of Fig. 16, a pair of slits 66B are formed in the second electrode 20B. One of the pair of slits 66B is formed between the edge relay portion 36B1 and the current collecting bundle portion 38B, and the other of the pair of slits 66B is formed between the edge relay portion 36B2 and the current collecting bundle portion 38B.

[0103] The slits 66B penetrate the second electrode 20B in the thickness direction of the electrode group 2. In each of the electrode plates 21B, the slits 66B penetrate the current collector 25B in the plate thickness direction. Each of the slits 66B extends along the length direction of the electrode group 2. Each of the slits 66B extends outward in the length direction of the electrode group 2 to the current collector edge 27B of the current collector 25B of the electrode plate 21B. In addition, the slits 66B are formed outward in the length direction of the electrode group 2 with respect to the inner edge extension portion 35B of the layer edge 31B of the active material-containing layer 26B.

[0104] In this modification, in forming the electrode plate 21A of the first electrode 20A, the uncoated belt portion 63A is cut out as described above, and a cut constituting a part of the slit 66A is formed in the uncoated belt portion 62A. In forming the electrode plate 21B of the second electrode 20B, the uncoated belt portion 62B is cut out as described above, and a cut constituting a part of the slit 66B is formed in the uncoated belt portion 63B. The slits 66A and 66B can be formed using a jig such as a knife. The slits 66A and 66B can also be formed by melting metal in a non-contact manner such as laser processing. Furthermore, the slits 66A and 66B can also be formed by performing an etching process such as wet etching while masking the parts other than the slits 66A and 66B. This modification also provides the same functions and effects as the above-mentioned embodiments including the first embodiment. That is, in this modified example as well, it is possible to increase the battery capacity of the battery 1 without increasing the external dimensions and volume, etc., of the electrode group 2 and the battery 1.

[0105] In addition, in this modification, the slit 66A is formed in the first electrode 20A as described above, so that the current collecting bundle portion 38A can easily bundle the multiple uncoated belt portions 37A. The formation of the slit 66A further appropriately prevents the current collecting bundle portion 38A of the first electrode 20A from contacting the second electrode 20B. Similarly, in this modification, the slit 66B is formed in the second electrode 20B as described above, so that the current collecting bundle portion 38B can easily bundle the multiple uncoated belt portions 37B. The formation of the slit 66B further appropriately prevents the current collecting bundle portion 38B of the second electrode 20B from contacting the first electrode 20A.

[0106] In the above-described embodiment and the like, in the first electrode 20A, the active material-containing layer 26A is adjacent to the current collecting bundle portion 38A from both sides in the width direction of the electrode group 2, with the edge relay portion 36A of the layer edge 31A as the boundary. In the second electrode 20B, the active material-containing layer 26B is adjacent to the current collecting bundle portion 38B from both sides in the width direction of the electrode group 2, with the edge relay portion 36B of the layer edge 31B as the boundary.

[0107] However, in the fifth modified example shown in FIG. 17, in the first electrode 20A, only one edge relay portion 36A is formed on the layer edge 31A of the active material-containing layer 26A. In the first electrode 20A, the active material-containing layer 26A is adjacent to the current collecting bundle portion 38A only from one side in the width direction of the electrode group 2, with the edge relay portion 36A of the layer edge 31A as a boundary. In this modified example, in the second electrode 20B, only one edge relay portion 36B is formed on the layer edge 31B of the active material-containing layer 26B. In the second electrode 20B, the active material-containing layer 26B is adjacent to the current collecting bundle portion 38B only from one side in the width direction of the electrode group 2, with the edge relay portion 36B of the layer edge 31B as a boundary.

[0108] In this modification, the configuration in which the current collecting bundle portion 38A is located inside the outer edge extension portion 33A of the layer edge 31A in the length direction of the electrode group 2 in the first electrode 20A is appropriately realized. In addition, the configuration in which the current collecting bundle portion 38B is located inside the outer edge extension portion 33B of the layer edge 31B in the length direction of the electrode group 2 is appropriately realized in the second electrode 20B. Therefore, this modification also achieves the same effects and advantages as the above-mentioned embodiments including the first embodiment. That is, in this modification, it is possible to increase the battery capacity of the battery 1 without increasing the external dimensions and volume of the electrode group 2 and the battery 1.

[0109] Here, from the above-mentioned embodiment and modified examples, in the first electrode 20A, the active material-containing layer 26A may be adjacent to the current collecting bundle portion 38A from at least one side in the width direction of the electrode group 2, with the edge relay portion 36A of the layer edge 31A as the boundary. This appropriately realizes a configuration in which the current collecting bundle portion 38A is located inside the outer edge extension portion 33A of the layer edge 31A in the length direction of the electrode group 2 in the first electrode 20A. And, in the second electrode 20B, the active material-containing layer 26B may be adjacent to the current collecting bundle portion 38B from at least one side in the width direction of the electrode group 2, with the edge relay portion 36B of the layer edge 31B as the boundary. This appropriately realizes a configuration in which the current collecting bundle portion 38B is located inside the outer edge extension portion 33B of the layer edge 31B in the length direction of the electrode group 2 in the second electrode 20B.

[0110] Second embodiment Next, a second embodiment will be described as a modification of the first embodiment. In the following description, the same components as those in the first embodiment are given the same reference numerals as those in the first embodiment, and the description thereof will be omitted. Fig. 18 shows a schematic cross section of the battery according to this embodiment perpendicular or substantially perpendicular to the depth direction. Fig. 19 shows a schematic perspective view of the electrode group 2 according to this embodiment.

[0111] As shown in Figs. 18 and 19, in this modified example, the electrode group 2 has a length direction (direction indicated by arrows L1 and L2), a width direction (direction indicated by arrows W1 and W2), and a thickness direction (direction indicated by arrows T1 and T2). In the electrode group 2, the first electrode 20A is composed of a plurality of electrode plates 21A, the second electrode 20B is composed of a plurality of electrode plates 21B, and the separator 22 is composed of a plurality of separator sheets 23. In the electrode group 2, the electrode plates 21A and 21B are alternately stacked in the thickness direction of the electrode group 2, and a corresponding one of the separator sheets 23 is disposed between the electrode plates 21A and 21B adjacent to each other in the thickness direction of the electrode group 2 (stacking direction of the electrode plates 21). In the electrode group 2 of the example in Fig. 19, the outermost layer in the thickness direction of the electrode group 2 is formed from a corresponding one of the separator sheets 23.

[0112] FIG. 20 is a schematic diagram of the first electrode 20A as viewed from the thickness direction of the electrode group 2. In FIG. 20, the first electrode 20A is shown as a projection from the thickness direction of the electrode group 2, and the second electrode 20B and the separator 22 are not shown. As shown in FIG. 20, in each of the electrode plates (first electrode plates) 21A in this embodiment, current collector edges 27A and 28A are formed as both edges of the current collector 25A in the length direction of the electrode group 2, and layer edges 31A and 32A are formed as both edges of the active material-containing layer 26A in the length direction of the electrode group 2. The layer edge (first layer edge) 31A includes an outer edge extension portion 33A, an inner edge extension portion 35A, and an edge relay portion 36A, as in the above-mentioned embodiment.

[0113] Also in this embodiment, a current collecting bundle portion (first current collecting bundle portion) 38A is formed in the first electrode 20A by bundling the uncoated belt portions 37A of the current collectors 25A of the multiple electrode plates 21A. The current collecting bundle portion 38A is formed between the outer edge extension portion 33A and the inner edge extension portion 35A of the layer edge 31A of the active material-containing layer 26A in the longitudinal direction of the electrode group 2. Therefore, also in this embodiment, the current collecting bundle portion 38A is located inside the outer edge extension portion 33A of the layer edge 31A in the longitudinal direction of the electrode group 2, and is located outside the inner edge extension portion 35A of the layer edge 31A in the longitudinal direction of the electrode group 2.

[0114] In the present embodiment, the first electrode 20A is also formed with a notch (first notch) 40A that opens outward in the length direction of the electrode group 2, and the notch 40A penetrates the first electrode 20A in the thickness direction of the electrode group 2 (the stacking direction of the electrode plates 21). However, in the present embodiment, the notch 40A is formed in the first electrode 20A at the end on the side where the current collector edge 28A of the current collector 25A and the layer edge 32A of the active material-containing layer 26A are located in the length direction of the electrode group 2. Therefore, in the first electrode 20A of the present embodiment, the active material-containing layer 26A is formed between the notch 40A and the current collecting bundle portion 38A in the length direction of the electrode group 2. Therefore, in the first electrode 20A, the notch 40A is located away from the current collecting bundle portion 38A in the length direction of the electrode group 2.

[0115] In this embodiment as well, in the projection of the electrode group 2 from the thickness direction, the notch 40A of the first electrode 20A is located at a position that does not overlap with the current collecting bundle portion 38A and is located away from the current collecting bundle portion 38A. Moreover, in this embodiment, in the first electrode 20A, a concave shape that is concave inward in the length direction of the electrode group 2 is formed by the notch 40A at each current collector edge 28A of the current collector 25A and each layer edge 32A of the active material-containing layer 26A. At each current collector edge 28A of the current collector 25A and each layer edge 32A of the active material-containing layer 26A, portions other than the notch 40A are provided extending along the width direction of the electrode group 2.

[0116] FIG. 21 is a schematic diagram of the second electrode 20B as viewed from the thickness direction of the electrode group 2. In FIG. 21, the second electrode 20B is shown as a projection from the thickness direction of the electrode group 2, and the first electrode 20A and the separator 22 are not shown. As shown in FIG. 21, in each of the electrode plates (second electrode plates) 21B in this embodiment, current collector edges 27B and 28B are formed as both edges of the current collector 25B in the length direction of the electrode group 2, and layer edges 31B and 32B are formed as both edges of the active material-containing layer 26B in the length direction of the electrode group 2. The layer edge (second layer edge) 31B includes an outer edge extension portion 33B, an inner edge extension portion 35B, and an edge relay portion 36B, as in the above-mentioned embodiment.

[0117] Also in this embodiment, a current collecting bundle portion (second current collecting bundle portion) 38B is formed in the second electrode 20B, in which the uncoated belt portions 37B of the current collectors 25B of the multiple electrode plates 21B are bundled together. The current collecting bundle portion 38B is formed between the outer edge extension portion 33B and the inner edge extension portion 35B of the layer edge 31B of the active material-containing layer 26B in the longitudinal direction of the electrode group 2. Therefore, also in this embodiment, the current collecting bundle portion 38B is located inside the outer edge extension portion 33B of the layer edge 31B in the longitudinal direction of the electrode group 2, and is located outside the inner edge extension portion 35B of the layer edge 31B in the longitudinal direction of the electrode group 2.

[0118] In the present embodiment, the second electrode 20B is also formed with a notch (second notch) 40B that opens outward in the length direction of the electrode group 2, and the notch 40B penetrates the second electrode 20B in the thickness direction of the electrode group 2 (the stacking direction of the electrode plates 21). However, in the present embodiment, the notch 40B is formed in the second electrode 20B at an end on the side where the current collector edge 28B of the current collector 25B and the layer edge 32B of the active material-containing layer 26B are located in the length direction of the electrode group 2. Therefore, in the second electrode 20B of the present embodiment, the active material-containing layer 26B is formed between the notch 40B and the current collecting bundle portion 38B in the length direction of the electrode group 2. Therefore, in the second electrode 20B, the notch 40B is located away from the current collecting bundle portion 38B in the length direction of the electrode group 2.

[0119] In this embodiment as well, in the projection of the electrode group 2 from the thickness direction, the notch 40B of the second electrode 20B is located at a position that does not overlap with the current collecting bundle portion 38B, and is located away from the current collecting bundle portion 38B. Moreover, in this embodiment, in the second electrode 20B, a concave shape that is concave inward in the length direction of the electrode group 2 is formed by the notch 40B at each current collector edge 28B of the current collector 25B and each layer edge 32B of the active material containing layer 26B. At each current collector edge 28B of the current collector 25B and each layer edge 32B of the active material containing layer 26B, the portions other than the notch 40B are extended along the width direction of the electrode group 2.

[0120] Fig. 22 shows the separator 22 in a schematic state as viewed from the thickness direction of the electrode group 2. In Fig. 22, the separator 22 is shown as a projection from the thickness direction of the electrode group 2, and the first electrode 20A and the second electrode 20B are not shown. As shown in Fig. 22, in the present embodiment as well, in each separator sheet 23, sheet edges 41, 42 are formed as both edges in the length direction of the electrode group 2.

[0121] In the present embodiment as well, a pair of separator notches 43A, 43B are formed in the separator 22. Each of the separator notches 43A, 43B opens outward in the longitudinal direction of the electrode group 2 and penetrates the separator 22 in the thickness direction of the electrode group 2. However, in the present embodiment, the separator notch 43A is formed in the separator 22 at an end portion on the side where the sheet edge 41 of the separator sheet 23 is located in the longitudinal direction of the electrode group 2, and the separator notch 43B is formed in the separator 22 at an end portion on the side where the sheet edge 42 of the separator sheet 23 is located in the longitudinal direction of the electrode group 2. Therefore, in the separator 22, the separator notches 43A, 43B are located apart from each other in the longitudinal direction of the electrode group 2.

[0122] FIG. 23 is a schematic diagram of the electrode group 2 as viewed from the thickness direction of the electrode group 2. That is, FIG. 23 shows the projection of the electrode group 2 from the thickness direction. As shown in FIG. 19 to FIG. 23, the electrode group 2 of this embodiment is different from the first embodiment and the like in that the current collector edge 27B and layer edge 31B of the second electrode 20B are located on the opposite side to the side where the current collector edge 27A and layer edge 31A of the first electrode 20A are located with respect to the active material-containing layer 26A of the first electrode 20A and the active material-containing layer 26B of the second electrode 20B in the length direction of the electrode group 2. Therefore, in the electrode group 2, the current collecting bundle portion 38B of the second electrode 20B is located on the opposite side to the side where the current collecting bundle portion 38A of the first electrode 20A is located with respect to the active material-containing layers 26A and 26B in the length direction of the electrode group 2. The notch 40B of the second electrode 20B is located, in the longitudinal direction of the electrode group 2, on the opposite side of the active material-containing layers 26A, 26B to the side on which the notch 40A of the first electrode 20A is located.

[0123] Due to the above-mentioned configuration, in the electrode group 2, the current collecting bundle portion 38B of the second electrode 20B is located away from the current collecting bundle portion 38A of the first electrode 20A in the length direction of the electrode group 2. Therefore, in the projection of the electrode group 2 from the thickness direction, the current collecting bundle portion 38B of the second electrode 20B is located at a position where it does not overlap with the current collecting bundle portion 38A of the first electrode 20A, and is located away from the current collecting bundle portion 38A. Also, in the electrode group 2, the notch 40B of the second electrode 20B is located away from the notch 40A of the first electrode 20A in the length direction of the electrode group 2. Therefore, in the projection of the electrode group 2 from the thickness direction, the notch 40B of the second electrode 20B is located at a position where it does not overlap with the notch 40A of the first electrode 20A, and is located away from the notch 40A. In addition, when a virtual central plane of the electrode group 2 in the longitudinal direction is defined, the current collecting bundle portions 38A, 38B may be arranged symmetrically (plane symmetrically) with respect to each other with respect to the aforementioned virtual central plane as the center, or they may not be arranged symmetrically (plane symmetrically) with respect to each other.

[0124] In the present embodiment, too, in projection of the electrode group 2 from the thickness direction, the notch (second notch) 40B of the second electrode 20B is positioned so as to overlap with the current collecting bundle portion (first current collecting bundle portion) 38A of the first electrode 20A. In projection of the electrode group 2 from the thickness direction, the notch (first notch) 40A of the first electrode 20A is positioned so as to overlap with the current collecting bundle portion (second current collecting bundle portion) 38B of the second electrode 20B.

[0125] In the electrode group 2 of this embodiment, the sheet edge 41 of the separator 22 is located on the side where the current collector edge 27A and layer edge 31A of the first electrode 20A are located, relative to the active material-containing layer 26A of the first electrode 20A and the active material-containing layer 26B of the second electrode 20B, in the length direction of the electrode group 2. Therefore, in the electrode group 2, the separator notch 43A of the separator 22 is located on the side where the current collector bundle portion 38A of the first electrode 20A and the notch 40B of the second electrode 20B are located, relative to the active material-containing layers 26A, 26B, in the length direction of the electrode group 2. Also, in the electrode group 2 of this embodiment, the sheet edge 42 of the separator 22 is located on the side where the current collector edge 27B and layer edge 31B of the second electrode 20B are located, relative to the active material-containing layers 26A, 26B, in the length direction of the electrode group 2. Therefore, in the electrode group 2, the separator notch 43B of the separator 22 is located on the side of the active material containing layers 26A, 26B in the longitudinal direction of the electrode group 2, on which the current collecting bundle portion 38B of the second electrode 20B and the notch 40A of the first electrode 20A are located.

[0126] In the present embodiment, too, in projection of the electrode group 2 from the thickness direction, the separator notch (first separator notch) 43A of the separator 22 is positioned to overlap with the current collecting bundle portion (first current collecting bundle portion) 38A of the first electrode 20A and the notch (second notch) 40B of the second electrode 20B. In projection of the electrode group 2 from the thickness direction, the separator notch (second separator notch) 43B of the separator 22 is positioned to overlap with the current collecting bundle portion (second current collecting bundle portion) 38B of the second electrode 20B and the notch (first notch) 40A of the first electrode 20A.

[0127] 18 and other figures, in this embodiment, the electrode group 2 is disposed in the internal cavity 8 with its length direction coinciding or approximately coinciding with the lateral direction of the battery 1. In addition, in the electrode group 2 disposed in the internal cavity 8, its width direction coincides or approximately coinciding with the height direction of the battery 1, and its thickness direction coincides or approximately coinciding with the depth direction of the battery 1.

[0128] In the internal cavity 8, the current collecting bundle portion 38A of the first electrode 20A and the notch 40B of the second electrode 20B are located on the opposite side of the active material-containing layers 26A, 26B from the side on which the current collecting bundle portion 38B of the second electrode 20B and the notch 40A of the first electrode 20A are located in the lateral direction of the battery 1. The separator notch 43A of the separator 22 is located on the side on which the current collecting bundle portion 38A of the first electrode 20A and the notch 40B of the second electrode 20B are located, relative to the active material-containing layers 26A, 26B in the lateral direction of the battery 1. In addition, in the lateral direction of the battery 1, the separator notch 43B of the separator 22 is located on the side of the active material containing layers 26A, 26B where the current collecting bundle portion 38B of the second electrode 20B and the notch 40A of the first electrode 20A are located.

[0129] Since the electrode group 2 is accommodated in the internal cavity 8 as described above, in each layer edge 31A of the active material-containing layer 26A of the first electrode 20A, the outer edge extension 33A and the inner edge extension 35A each extend along the height direction of the battery 1, and the edge relay portion 36A extends along the lateral direction of the battery 1. In each layer edge 31A of the active material-containing layer 26A, the inner edge extension 35A is located inside the outer edge extension 33A in the lateral direction of the battery 1. In the first electrode 20A, the current collecting bundle portion 38A is formed between the outer edge extension 33A and the inner edge extension 35A in the lateral direction of the battery 1.

[0130] In addition, the layer edge 31B of the second electrode 20B is located on the opposite side of the active material-containing layers 26A, 26B from the layer edge 31A of the first electrode 20A in the lateral direction of the battery 1. In each layer edge 31B of the active material-containing layer 26B of the second electrode 20B, the outer edge extension 33B and the inner edge extension 35B extend along the height direction of the battery 1, and the edge relay portion 36B extends along the lateral direction of the battery 1. In each layer edge 31B of the active material-containing layer 26B, the inner edge extension 35B is located inside the outer edge extension 33B in the lateral direction of the battery 1. In the second electrode 20B, the current collecting bundle portion 38B is formed between the outer edge extension 33B and the inner edge extension 35B in the lateral direction of the battery 1.

[0131] FIG. 24 is a schematic perspective view of any one of the pair of lead members 16. As shown in FIG. 18 and FIG. 24, in this embodiment, each of the lead members 16 includes a leg plate portion 57 serving as an extended plate portion in addition to a top plate portion 51 and a joint plate portion 52. In this embodiment, the top plate portion 51 of each of the lead members 16 is disposed between the electrode group 2 and the lid member 5 in the height direction of the battery 1, and between the electrode group 2 and the spacer 17. In the internal cavity 8, each of the top plate portions 51 of the lead members 16 is disposed with the plate thickness direction coinciding or approximately coinciding with the height direction of the battery 1. Each of the top plate portions 51 of the lead members 16 extends along the lateral direction of the battery 1. In this embodiment, each of the lead members 16 has a through hole 53 formed in the top plate portion 51. A corresponding one of the pair of terminals 13 is connected to each of the top plate portions 51 of the lead members 16 through the through hole 53.

[0132] In one example, instead of through holes 53, a connection structure such as a protrusion is provided on top plate portion 51 of each of lead members 16, and a hole is formed in each of terminals 13. In this case, each of a pair of lead members 16 is connected to one of the corresponding terminals 13 with the connection structure inserted into the corresponding hole of one of the terminals 13. Also, in each of lead members 16, bonding and electrical characteristics are ensured, and to the extent that reliability as a component of battery 1 is ensured, bonding plate portion 52 is formed to an appropriate plate thickness, outer shape, etc.

[0133] In this embodiment, in each of the lead members 16, a leg plate portion 57 serving as an extended plate portion is connected to the top plate portion 51, and the leg plate portion 57 extends along the height direction of the battery 1. In each of the lead members 16, the leg plate portion 57 extends along the width direction of the electrode group 2, and extends from the connection position to the top plate portion 51 toward the side where the bottom wall 6 is located in the height direction of the battery 1. In the internal cavity 8, the leg plate portion 57 of each of the lead members 16 is adjacent to the electrode group 2 from the outside in the longitudinal direction of the electrode group 2, and is adjacent to the electrode group 2 from the outside in the lateral direction of the battery 1.

[0134] In the example shown in Figs. 18 and 24, the leg plate portion 57 of the lead member 16A is located outside the outer edge extension portion 33A of the layer edge 31A of the first electrode 20A in the length direction of the electrode group 2 and outside the lateral direction of the battery 1. The leg plate portion 57 of the lead member 16B is located outside the outer edge extension portion 33B of the layer edge 31B of the second electrode 20B in the length direction of the electrode group 2 and outside the lateral direction of the battery 1. Therefore, in the internal cavity of the battery 1, the leg plate portion 57 of each of the lead members 16 is disposed between the electrode group 2 and the peripheral wall 7, and between the corresponding one of the pair of side walls 11 and the electrode group 2. In each of the lead members 16, the leg plate portion 57, which is an extension plate portion, is disposed in the internal cavity 8 with the plate thickness direction coinciding or approximately coinciding with the lateral direction of the battery 1.

[0135] In this embodiment, in each of the lead members 16, the bonding plate portion 52 protrudes from the leg plate portion 57, which is an extended plate portion, toward the inside in the longitudinal direction of the electrode group 2. In this embodiment, each of the bonding plate portions 52 of the lead members 16 protrudes from the leg plate portion 57 toward the inside in the lateral direction of the battery 1. In the internal cavity 8, each of the bonding plate portions 52 of the lead members 16 is arranged with the plate thickness direction coinciding or approximately coinciding with the depth direction of the battery 1. Note that in the example of the lead member 16 shown in FIG. 24, in a cross section that is perpendicular or approximately perpendicular to the width direction of the electrode group 2 and that passes through the bonding plate portion 52, each of the lead members 16 has a T-shape or approximately T-shape.

[0136] In the present embodiment, in each of the lead members 16, the bonding plate portion 52 is bonded to one of the current collecting bundle portion 38A of the first electrode 20A and the current collecting bundle portion 38B of the second electrode 20B. Therefore, in the lead member 16A, the bonding plate portion 52 is bonded to the current collecting bundle portion 38A of the first electrode 20A, and in the lead member 16B, the bonding plate portion 52 is bonded to the current collecting bundle portion 38B of the second electrode 20B.

[0137] In this embodiment, as in the first embodiment, the above-mentioned configuration makes it possible to increase both the area where the active material-containing layer 26A is applied on the current collector 25A and the area where the active material-containing layer 26B is applied on the current collector 25B, without increasing the external dimensions and volume, etc., of the electrode group 2 and the battery 1. This makes it possible to further increase the battery capacity of the battery 1 without increasing the external dimensions and volume, etc., of the electrode group 2 and the battery 1.

[0138] In this embodiment, in each of the lead members 16, the dimension of the top plate portion 51 along the depth direction of the exterior part 3 (thickness direction of the electrode group 2), i.e., the plate width of the top plate portion 51, is made the same or approximately the same as the dimension of the electrode group 2 along the thickness direction, so that the dimension of the top plate portion 51 along the depth direction of the exterior part 3 is increased. In each of the lead members 16, the dimension of the top plate portion 51 along the depth direction of the exterior part 3 is increased, so that even if the dimension of the top plate portion 51 along the height direction of the exterior part 3, i.e., the plate thickness of the top plate portion 51, is reduced, the cross-sectional area of ​​the top plate portion 51 is ensured to a certain degree. As a result, in each of the lead members 16, even if the dimension of the top plate portion 51 along the height direction of the exterior part 3 is reduced, the electrical resistance is prevented from increasing beyond a reference level. In addition, in each of the lead members 16, the dimension of the top plate portion 51 along the height direction of the exterior part 3 is reduced, so that the dimension of the electrode group 2 along the width direction of the electrode group 2 (height direction of the exterior part 3) can be increased. By increasing the dimension of the electrode group 2 along the width direction of the electrode group 2, the area where the active material-containing layer 26A is applied to the current collector 25A and the area where the active material-containing layer 26B is applied to the current collector 25B are further increased.

[0139] (Other variations) Even if the lead member 16 is configured to be formed of the top plate portion 51, the leg plate portion 57, and the bonding plate portion 52 as in the second embodiment, the cross-sectional shape of the lead member 16 in a cross section perpendicular or substantially perpendicular to the width direction of the electrode group 2 and passing through the bonding plate portion 52 can be appropriately changed as described above in the modified example of the first embodiment. Also, as described above in the modified example of the first embodiment, in the lead member 16A, two current collecting bundle portions 38A may be bonded to one bonding plate portion 52, and in the lead member 16B, two current collecting bundle portions 38B may be bonded to one bonding plate portion 52. Also, as described above in the modified example of the first embodiment, one lead member may be provided with a plurality of bonding plate portions 52.

[0140] In a modified example, similarly to the second embodiment, the current collecting bundle portion 38B of the second electrode 20B is located on the opposite side to the side on which the current collecting bundle portion 38A of the first electrode 20A is located, with respect to the active material containing layers 26A, 26B, in the longitudinal direction of the electrode group 2. As described above in the modified example of the first embodiment, in the electrode group 2, a slit (first slit) 66A is formed in the first electrode 20A, and a slit (second slit) 66B is formed in the second electrode 20B.

[0141] In a modified example, similar to the second embodiment, the current collecting bundle portion 38B of the second electrode 20B is located on the opposite side of the active material-containing layers 26A, 26B from the side on which the current collecting bundle portion 38A of the first electrode 20A is located in the length direction of the electrode group 2. As described above in the modified example of the first embodiment, in the first electrode 20A, the active material-containing layer 26A is adjacent to the current collecting bundle portion 38A only from one side in the width direction of the electrode group 2, with the edge relay portion 36A of the layer edge 31A as the boundary. In the second electrode 20B, the active material-containing layer 26B is adjacent to the current collecting bundle portion 38B only from one side in the width direction of the electrode group 2, with the edge relay portion 36B of the layer edge 31B as the boundary.

[0142] As described above, the configurations of the electrode group 2 and lead members 16 of the second embodiment can also be appropriately changed as described above in the modified example of the first embodiment. Even when the configurations of the electrode group 2 and lead members 16 of the second embodiment are changed as described above, the same actions and effects as those of the above-mentioned embodiments including the first embodiment are achieved. Therefore, even when the configurations of the electrode group 2 and lead members 16 of the second embodiment are changed as described above, it is possible to increase the battery capacity of the battery 1 without increasing the external dimensions and volume of the electrode group 2 and battery 1.

[0143] In the above-described embodiment and the like, the electrode group 2 has a stack structure in which a plurality of electrode plates 21 (21A, 21B) are stacked in the thickness direction of the electrode group 2, but the electrode group 2 may be formed in a so-called wound structure. In this case, in the electrode group 2, the first electrode 20A, the second electrode 20B, and the separator 22 are wound around a winding axis with the separator 22 interposed between the first electrode 20A and the second electrode 20B. The winding axis is aligned along the length direction of the electrode group 2.

[0144] Even when the electrode group 2 is formed in a wound structure, in the first electrode 20A, the current collecting bundle portion (first current collecting bundle portion) 38A of the current collector 25A is formed between the outer edge extension portion 33A and the inner edge extension portion 35A of the layer edge 31A of the active material-containing layer 26A in the length direction of the electrode group 2. Therefore, in the first electrode 20A, the current collecting bundle portion 38A to which the lead member 16 is joined is formed inside the outer edge extension portion 33A of the layer edge 31A of the active material-containing layer 26A in the length direction of the electrode group 2. Therefore, as in the above-mentioned embodiment, it is possible to increase the area where the active material-containing layer 26A is applied to the current collector 25A while maintaining the outer dimensions, volume, etc. of the electrode group 2. Therefore, it is possible to increase the battery capacity of the battery 1 without increasing the outer dimensions, volume, etc. of the electrode group 2 and the battery 1.

[0145] Also, in the case where the electrode group 2 is formed in a wound structure, in the second electrode 20B, the current collecting bundle portion (second current collecting bundle portion) 38B of the current collector 25B is formed between the outer edge extension portion 33B and the inner edge extension portion 35B of the layer edge 31B of the active material-containing layer 26B in the length direction of the electrode group 2. Therefore, in the second electrode 20B, the current collecting bundle portion 38B to which the lead member 16 is joined is formed on the inner side in the length direction of the electrode group 2 with respect to the outer edge extension portion 33B of the layer edge 31B of the active material-containing layer 26B. Therefore, as in the above-mentioned embodiment, it is possible to increase the area where the active material-containing layer 26B is applied to the current collector 25B while maintaining the outer dimensions, volume, etc. of the electrode group 2. Therefore, it is possible to further increase the battery capacity of the battery 1 without increasing the outer dimensions, volume, etc. of the electrode group 2 and the battery 1.

[0146] In one modified example, only the current collecting bundle portion 38A to which the lead member 16 is joined in the first electrode 20A is formed in the same manner as in any of the above-mentioned embodiments, and in the second electrode 20B, the outer edge extension portion 33B and the inner edge extension portion 35B are not formed on the layer edge 31B of the active material-containing layer 26B. In this case, in the second electrode 20B, the current collecting bundle portion 38B to which the lead member 16 is joined has a configuration different from any of the above-mentioned embodiments, for example, protruding from the layer edge 31B of the active material-containing layer 26B to the outside in the longitudinal direction of the electrode group 2.

[0147] In this modification, in the first electrode 20A, the current collecting bundle portion (first current collecting bundle portion) 38A of the current collector 25A is formed between the outer edge extension portion 33A and the inner edge extension portion 35A of the layer edge 31A of the active material-containing layer 26A in the length direction of the electrode group 2. Therefore, in the first electrode 20A, the current collecting bundle portion 38A to which the lead member 16 is joined is formed inside the outer edge extension portion 33A of the layer edge 31A of the active material-containing layer 26A in the length direction of the electrode group 2. Therefore, as in the above embodiment, it is possible to increase the area where the active material-containing layer 26A is applied to the current collector 25A while maintaining the outer dimensions, volume, etc. of the electrode group 2. Therefore, it is possible to increase the battery capacity of the battery 1 without increasing the outer dimensions, volume, etc. of the electrode group 2 and the battery 1.

[0148] According to at least one of these embodiments or examples, in an electrode group including a first electrode and a second electrode, the active material-containing layer of the first electrode has a layer edge that is an edge on one side in the length direction, and an inner edge extension is provided on the layer edge of the active material-containing layer along a width direction intersecting the length direction, on the inner side in the length direction relative to the outer edge extension. In the first electrode, the current collector has a current collecting bundle portion in which only the uncoated portion of the active material-containing layer is bundled, and the current collecting bundle portion is formed between the outer edge extension and the inner edge extension in the length direction. This makes it possible to provide an electrode group and a battery that can increase the battery capacity without increasing the external dimensions.

[0149] Although some embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their modifications are included in the scope and spirit of the invention, and are included in the scope of the invention and its equivalents described in the claims. [Explanation of symbols]

[0150] REFERENCE SIGNS LIST 1...battery, 2...electrode group, 3...exterior part, 4...exterior container, 5...lid member, 6...bottom wall, 7...periphery wall, 8...internal cavity, 13...terminal, 16...lead member, 20A...first electrode, 20B...second electrode, 22...separator, 25A...current collector (first current collector), 25B...current collector (second current collector), 26A...active material-containing layer (first active material-containing layer), 26B...active material-containing layer (second active material-containing layer), 31A...layer edge (first layer edge), 31B...layer edge (second layer edge), 33A...outer edge extension portion (first outer edge extension portion), 33B...outer edge extension portion (second outer edge extension portion), 35A...inner edge extension portion (first inner edge extension portion), 35B...inner edge extension portion (second inner edge extension portion), 36A...edge transition portion (first edge transition portion), 36B...edge transition portion (second edge transition portion), 40A...notch (first notch), 40B...notch (second notch), 43A...separator notch (first separator notch), 43B...separator notch (second separator notch), 51...top plate portion, 52...jointing plate portion, 57...leg plate portion.

Claims

1. a first electrode and a second electrode of opposite polarity to the first electrode; the first electrode comprises a first current collector having electrical conductivity and a first active material-containing layer applied to a surface of the first current collector; the first active material-containing layer has a first layer edge that is an edge on one side in a length direction, The first layer edge includes a first outer edge extension extending along a width direction intersecting with a length direction, and a first inner edge extension extending along the width direction on the inner side of the first outer edge extension in the length direction, the first current collector includes a first current collecting bundle part in which only a portion where the first active material-containing layer is not coated is bundled; The first current collecting bundle portion is formed between the first outer edge extension portion and the first inner edge extension portion in the longitudinal direction. Electrode group.

2. The first layer edge of the first active material-containing layer includes a first edge relay portion extending along the length direction in a state relaying between the first outer edge extension portion and the first inner edge extension portion, the first active material-containing layer is adjacent to the first current collecting bundle portion from the inside in the length direction, with the first inner edge extension portion as a boundary, and is adjacent to the first current collecting bundle portion from at least one side in the width direction, with the first edge relay portion as a boundary; The electrode group of claim 1.

3. The second electrode has a notch formed therein, the notch penetrating the second electrode in a thickness direction intersecting both the length direction and the width direction and opening outward in the length direction; When projected in the thickness direction, the notch of the second electrode is positioned to overlap the first current collecting bundle portion of the first electrode. The electrode group of claim 1.

4. Further comprising a separator for electrically insulating the first electrode from the second electrode, a separator notch is formed in the separator, the separator notch penetrating the separator in the thickness direction and opening to the outside in the length direction; When projected from the thickness direction, the separator notch is positioned to overlap with the first current collecting bundle portion of the first electrode and the notch of the second electrode. The electrode group of claim 3.

5. the second electrode comprises a second current collector having electrical conductivity and a second active material-containing layer applied to a surface of the second current collector; the second active material-containing layer has a second layer edge that is an edge on one side in the longitudinal direction, The second layer edge includes a second outer edge extension extending along the width direction, and a second inner edge extension extending along the width direction on the inner side of the second outer edge extension in the length direction, the second current collector includes a second current collecting bundle part in which only the portions where the second active material-containing layer is not coated are bundled, the second current collecting bundle portion is formed between the second outer edge extension portion and the second inner edge extension portion in the length direction, and is located away from the first current collecting bundle portion of the first electrode when projected from a thickness direction intersecting both the length direction and the width direction. The electrode group of claim 1.

6. the second layer edge of the second active material-containing layer includes a second edge relay portion extending along the length direction in a state relaying between the second outer edge extension portion and the second inner edge extension portion, the second active material-containing layer is adjacent to the second current collecting bundle portion from the inside in the length direction, with the second inner edge extension portion as a boundary, and is adjacent to the second current collecting bundle portion from at least one side in the width direction, with the second edge relay portion as a boundary; The electrode group of claim 5.

7. a first notch is formed in the first electrode, the first notch penetrating the first electrode in the thickness direction and opening outward in the length direction; When projected from the thickness direction, the first notch of the first electrode is positioned to overlap the second current collecting bundle portion of the second electrode, a second notch is formed in the second electrode, the second notch penetrating the second electrode in the thickness direction and opening to the outside in the length direction; In the projection from the thickness direction, the second notch of the second electrode is positioned to overlap with the first current collecting bundle portion of the first electrode. The electrode group of claim 5.

8. Further comprising a separator for electrically insulating the first electrode from the second electrode, a first separator notch and a second separator notch are formed in the separator at positions spaced apart from each other; each of the first separator notch and the second separator notch penetrates the separator in the thickness direction and opens to the outside in the length direction; When projected from the thickness direction, the first separator notch is positioned to overlap the first current collecting bundle portion of the first electrode and the second notch of the second electrode, In the projection from the thickness direction, the second separator notch is positioned to overlap the second current collecting bundle portion of the second electrode and the first notch of the first electrode. The electrode group of claim 7.

9. An electrode group according to any one of claims 1 to 8; a lead member having electrical conductivity and joined to the first current collecting bundle portion of the first current collector of the first electrode; Equipped with The lead member is an extension plate portion adjacent to the electrode group from the outside in the longitudinal direction and located on the outside in the longitudinal direction of the electrode group relative to the first outer edge extension portion of the first layer edge; a joining plate portion protruding from the extension plate portion toward the inside in the longitudinal direction of the electrode group and joined to the first current collecting bundle portion; Equipped with a battery.

10. an exterior part having an internal cavity formed therein for accommodating the electrode group and the lead member; a terminal attached to the exterior portion in a state where it is exposed to the outside and electrically connected to the first electrode of the electrode group via the lead member; 10. The battery of claim 9, further comprising:

11. The exterior part is an outer container including a bottom wall and a peripheral wall, the inner cavity being open to a side opposite to a side on which the bottom wall is located in a height direction of the exterior part; a cover member attached to the peripheral wall of the outer container in a state where the opening of the internal cavity is closed, and to which the terminal is attached in a state where the terminal is exposed to the outside on an outer surface of the cover member; 11. The battery of claim 10 comprising:

12. the electrode group is accommodated in the internal cavity with the length direction of the electrode group aligned with the height direction of the exterior part, the extension plate portion of the lead member is adjacent to the electrode group from a side where the lid member is located in the height direction, the joining plate portion of the lead member protrudes from the extension plate portion toward a side where the bottom wall is located in the height direction; 12. The battery of claim 11.

13. the electrode group is accommodated in the internal cavity with the width direction of the electrode group aligned with the height direction of the exterior part, the extension plate portion of the lead member is adjacent to the electrode group from an outer side in a lateral direction intersecting the height direction, The joining plate portion of the lead member protrudes from the extending plate portion toward the inside in the lateral direction.

12. The battery of claim 11.

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