Battery

Abstract

To provide a battery capable of increasing a space that a plurality of electrode groups in an internal cavity of an outer container occupy in a configuration where collector tabs of the plurality of electrode groups protrude toward a side on which a lid member is located.SOLUTION: A battery comprises an outer container 3, a lid member 5, a plurality of electrode groups 2A and 2B, first leads 23A, second leads 23B, and electrode terminals 21. The lid member 5 covers an opening of an internal cavity of the outer container 3. The plurality of electrode groups 2A and 2B are housed in the internal cavity of the outer container 3. In a first electrode group 2A, each first collector tab 17A protruding toward a side on which the lid member 5 is located is bonded with each first lead 23A. In a second electrode group 2B different from the first electrode group 2A, each second collector tab 17B protruding toward a side on which the lid member 5 is located is bonded with each second lead 23B different from the first lead 23A. Each electrode terminal 21 exposed on an outer surface of the lid member 5 is connected with the first lead 23A and the second lead 23B together.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] Embodiments of the present invention relate to batteries.

Background Art

[0002] As a battery such as a lithium-ion secondary battery, there is one in which an electrode group including a positive electrode and a negative electrode is housed in an internal cavity of an exterior container. In such a battery, the exterior container includes a bottom wall and a peripheral wall, and the internal cavity of the exterior container opens to the side opposite to the bottom wall in the height direction of the battery. And, a lid member is attached to the peripheral wall of the exterior container, and the opening of the internal cavity is closed by the lid member. Further, in the battery, electrode terminals are provided on the outer surface of the lid member in a state of being exposed to the outside of the battery.

[0003] Further, as a battery, a plurality of electrode groups are housed in the internal cavity of the exterior container as described above, and a current collecting tab projects toward the side where the lid member is located in each of the plurality of electrode groups. In the internal cavity of such a battery, a connecting member such as a lead is disposed between the current collecting tab and the lid member in the height direction of the battery. And, the current collecting tabs of each of the plurality of electrode groups are electrically connected to the electrode terminals via a connecting member such as a lead.

[0004] In a battery in which the current collecting tabs of a plurality of electrode groups project toward the side where the lid member is located in the internal cavity as described above, it is required to reduce the space occupied by a connecting member such as a lead in the internal cavity and increase the space occupied by the plurality of electrode groups in the internal cavity. And, by increasing the space occupied by the plurality of electrode groups, it is required to realize a higher capacity of the electrode group without increasing the size of the battery.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Patent Document 2

[0006] The problem that the present invention aims to solve is to provide a battery in which the space occupied by the multiple electrode groups in the internal cavity of the outer container can be increased, in a configuration in which the current-collecting tabs of the multiple electrode groups protrude toward the side where the lid member is located. [Means for solving the problem]

[0007] According to the embodiment, the battery comprises an outer casing, a lid member, a plurality of electrode groups, a first current collector tab, a second current collector tab, a first lead, a second lead, and electrode terminals. The outer casing has a bottom wall and a peripheral wall, and an internal cavity is formed in the outer casing that opens in the height direction to the side opposite to the side where the bottom wall is located. The lid member is attached to the peripheral wall of the outer casing in a state that closes the opening of the internal cavity. Each of the plurality of electrode groups comprises a positive electrode and a negative electrode, and the plurality of electrode groups are housed in the internal cavity of the outer casing. The first current collector tab protrudes toward the side where the lid member is located in the first electrode group, which is one of the plurality of electrode groups, and the second current collector tab protrudes toward the side where the lid member is located in the second electrode group, which is one of the plurality of electrode groups separate from the first electrode group. The first current collector tab is joined to the first lead. The second lead is formed separately from the first lead, and a second current-collecting tab is joined to the second lead. The electrode terminals are exposed to the outside on the outer surface of the cover member, and both the first and second leads are connected to the electrode terminals. [Brief explanation of the drawing]

[0008] [Figure 1] Figure 1 is a schematic perspective view showing a battery according to the first embodiment. [Figure 2] Figure 2 is a schematic perspective view showing a disassembled battery according to the first embodiment. [Figure 3]Figure 3 is a schematic perspective view showing the electrical connection structure of multiple electrode groups to one of a pair of electrode terminals and the configuration of its vicinity in a battery according to the first embodiment. [Figure 4] Figure 4 is a schematic diagram showing the electrical connection structure of multiple electrode groups to one of a pair of electrode terminals and the configuration of its vicinity in a battery according to the first embodiment, as viewed from one side in the depth direction of the battery. [Figure 5] Figure 5 is a schematic diagram showing the electrical connection structure of multiple electrode groups to one of a pair of electrode terminals and the configuration of its vicinity in a battery according to the first embodiment, as viewed from one side of the battery in the lateral direction. [Figure 6] Figure 6 is a schematic perspective view showing one of a pair of leads (the first lead) and one of a pair of leads (the second lead) in a battery according to the first embodiment. [Figure 7] Figure 7 is a schematic diagram showing the electrical connection structure of multiple electrode groups to one of a pair of electrode terminals and the configuration of its vicinity in the battery according to the first modified example, as viewed from one side in the depth direction of the battery. [Figure 8] Figure 8 is a schematic perspective view showing one of the pair of leads (the first lead) in a battery according to the second modified example. [Figure 9] Figure 9 is a schematic diagram showing the electrical connection structure of multiple electrode groups to one of a pair of electrode terminals and the configuration of its vicinity in a battery according to the third modified example, as viewed from one side of the battery in the lateral direction. [Modes for carrying out the invention]

[0009] The embodiments will be described below with reference to the drawings.

[0010] (First embodiment) Figures 1 and 2 show a battery 1 according to the first embodiment. As shown in Figures 1 and 2, the battery 1 comprises a plurality of electrode groups 2A, 2B, an outer casing 3, and a lid member 5. The outer casing 3 and the lid member 5 are each made of a metal such as aluminum, aluminum alloy, iron, copper, or stainless steel. Here, the battery 1 (outer casing 3) has a depth direction (directions indicated by arrows X1 and X2), a lateral direction (directions indicated by arrows Y1 and Y2) that intersects (orthogonal or approximately orthogonal to) the depth direction, and a height direction (directions indicated by arrows Z1 and Z2) that intersects (orthogonal or approximately orthogonal to) both the depth direction and the lateral direction. In both the battery 1 and the outer casing 3, the dimensions in the depth direction are smaller than the dimensions in the lateral direction and the dimensions in the height direction, respectively. Note that Figure 1 is a perspective view, and Figure 2 is a perspective view showing the battery 1 in an exploded state.

[0011] The outer container 3 comprises a bottom wall 6 and a peripheral wall 7. Inside the outer container 3, an internal cavity 8 in which the electrode group 2 is housed is defined by the bottom wall 6 and the peripheral wall 7. In the outer container 3, the internal cavity 8 opens in the height direction to the side opposite to where the bottom wall 6 is located. The peripheral wall 7 comprises two pairs of side walls 11 and 12. The pair of side walls 11 face each other in the lateral direction, with the internal cavity 8 in between. The pair of side walls 12 face each other in the depth direction, with the internal cavity 8 in between. 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 lid member 5 is attached to the peripheral wall 7 at the end opposite to the bottom wall 6. Thus, the lid member 5 closes the opening of the internal cavity 8 in the outer container 3. The lid member 5 and the bottom wall 6 face each other in the height direction, with the internal cavity 8 in between.

[0012] In an example such as Figure 1, two electrode groups 2A and 2B are arranged in an internal cavity 8. In the internal cavity 8, the multiple (two) electrode groups 2A and 2B are arranged side by side in the depth direction. Electrode group (first electrode group) 2A is arranged adjacent to electrode group (second electrode group) 2B in the depth direction. Each of electrode groups 2A and 2B includes a positive electrode 15 and a negative electrode 16. In each of electrode groups 2A and 2B, a separator (not shown) is interposed between the positive electrode 15 and the negative electrode 16. In each of electrode groups 2A and 2B, the separator is formed from an electrically insulating material and electrically insulates the positive electrode 15 from the negative electrode 16. Furthermore, electrode group 2A includes a pair of current collecting tabs (first current collecting tabs) 17A, and electrode group 2B includes a pair of current collecting tabs (second current collecting tabs) 17B.

[0013] In each of electrode groups 2A and 2B, the positive electrode 15 comprises a positive electrode current collector such as a positive electrode current collector foil, and a positive electrode active material-containing layer (not shown) supported on the surface of the positive electrode current collector. The positive electrode current collector is not limited to these, but for example, it may be aluminum foil or aluminum alloy foil, with 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 positive electrode active materials are not limited to these, but include oxides, sulfides, and polymers that can intercept and deintercept lithium ions. In electrode group 2A, the portion of the positive electrode current collector that does not support the positive electrode active material-containing layer becomes one of a pair of current collector tabs 17A, which is the positive electrode current collector tab (first positive electrode current collector tab). In electrode group 2B, the portion of the positive electrode current collector that does not support the positive electrode active material layer becomes one of the pair of current collector tabs 17B, which is the positive electrode current collector tab (second positive electrode current collector tab).

[0014] In each of the electrode groups 2A and 2B, the negative electrode 16 includes a negative electrode current collector such as a negative electrode current collecting foil, and a negative electrode active material-containing layer (not shown) supported on the surface of the negative electrode current collector. The negative electrode current collector is, but not limited to, for example, aluminum foil, aluminum alloy foil, copper foil, etc., and has a thickness of about 5 μm to 20 μm. The negative electrode active material-containing layer includes a negative electrode active material and may optionally contain a binder and a conductive agent. The negative electrode active material is not particularly limited, and examples thereof include metal oxides, metal sulfides, metal nitrides, and carbon materials that can occlude and release lithium ions. In the electrode group 2A, the portion of the negative electrode current collector where the negative electrode active material-containing layer is not supported becomes a negative electrode current collecting tab (first negative electrode current collecting tab) that is the other than the positive electrode current collecting tab of the pair of current collecting tabs 17A. And in the electrode group 2B, the portion of the negative electrode current collector where the negative electrode active material-containing layer is not supported becomes a negative electrode current collecting tab (second negative electrode current collecting tab) that is the other than the positive electrode current collecting tab of the pair of current collecting tabs 17B.

[0015] In each of the electrode groups 2A and 2B, a length direction (the directions indicated by arrow Z3 and arrow Z4), a width direction (the directions indicated by arrow Y3 and arrow Y4) that intersects (is orthogonal or substantially orthogonal) to the length direction, and a thickness direction (the directions indicated by arrow X3 and arrow X4) that intersects (is orthogonal or substantially orthogonal) to both the length direction and the width direction are defined. In each of the electrode groups 2A and 2B, the dimension in the thickness direction is smaller than each of the dimensions in the length direction and the width direction. Each of the electrode groups 2A and 2B is formed in a flat shape.

[0016] In electrode group 2A, the pair of current collector tabs (positive electrode current collector tab and negative electrode current collector tab) 17A protrude to one side in the longitudinal direction relative to the positive electrode active material-containing layer, the negative electrode active material-containing layer, and the separator, and the pair of current collector tabs 17A protrude to the same side relative to each other in the longitudinal direction. Furthermore, in electrode group 2A, the pair of current collector tabs 17A are formed spaced apart from each other in the width direction. Similarly, in electrode group 2B, the pair of current collector tabs (positive electrode current collector tab and negative electrode current collector tab) 17B protrude to one side in the longitudinal direction relative to the positive electrode active material-containing layer, the negative electrode active material-containing layer, and the separator, and the pair of current collector tabs 17B protrude to the same side relative to each other in the longitudinal direction. Furthermore, in electrode group 2B, the pair of current collector tabs 17B are formed spaced apart from each other in the width direction.

[0017] In one example, in each of the electrode groups 2A and 2B, the positive electrode 15, the negative electrode 16, and the separator are wound together with a separator sandwiched between the positive electrode active material-containing layer and the negative electrode active material-containing layer, so that each of the electrode groups 2A and 2B has a wound structure. In another example, each of the electrode groups 2A and 2B has a stack structure in which multiple positive electrodes 15 and multiple negative electrodes 16 are alternately stacked, with a separator provided between the positive electrode 15 and the negative electrode 16. Furthermore, in electrode group 2A, multiple strip-shaped portions are bound together in each of the pair of current-collecting tabs 17A, and in electrode group 2B, multiple strip-shaped portions are bound together in each of the pair of current-collecting tabs 17B.

[0018] In this embodiment, each of the electrode groups 2A and 2B is disposed in the internal cavity 8 in a state where the longitudinal direction thereof coincides with or substantially coincides with the height direction of the battery 1. In each of the electrode groups 2A and 2B, the width direction coincides with or substantially coincides with the lateral direction of the battery 1, and the thickness direction coincides with or substantially coincides with the depth direction of the battery 1. Further, the electrode group 2A is disposed in the internal cavity 8 with a pair of current collecting tabs 17A protruding toward the side where the lid member 5 is located in the height direction of the battery 1, and the electrode group 2B is disposed in the internal cavity 8 with a pair of current collecting tabs 17B protruding toward the side where the lid member 5 is located in the height direction of the battery 1. In the electrode group 2A, the pair of current collecting tabs 17A are arranged away from each other in the lateral direction of the battery 1, and the positive current collecting tab (one of the 17A's) does not contact the negative current collecting tab (the other one different from the positive current collecting tab of the 17A's). In the electrode group 2B, the pair of current collecting tabs 17B are arranged away from each other in the lateral direction of the battery 1, and the positive current collecting tab (one of the 17B's) does not contact the negative current collecting tab (the other one different from the positive current collecting tab of the 17B's).

[0019] Also, in the internal cavity 8, an electrolytic solution (not shown) is held (impregnated) in each of the electrode groups 2A and 2B. The electrolytic solution may be a non-aqueous electrolytic solution in which an electrolyte is dissolved in an organic solvent, or may be an aqueous electrolytic solution such as an aqueous solution. Instead of the electrolytic solution, a gel-like electrolyte may be used, or a solid electrolyte may be used. When the solid electrolyte is used as the electrolyte, in each of the electrode groups 2A and 2B, the solid electrolyte intervenes between the positive electrode 15 and the negative electrode 16 instead of the separator. In this case, in each of the electrode groups 2A and 2B, the positive electrode 15 is electrically insulated from the negative electrode 16 by the solid electrolyte.

[0020] In battery 1, a pair of electrode terminals 21 are attached to the lid member 5. The electrode terminals 21 are made of a conductive material such as metal. One of the pair of electrode terminals 21 is the positive terminal of battery 1, and the other electrode terminal 21 is the negative terminal of battery 1. Each of the electrode terminals 21 is positioned on the outer surface of the lid member 5, exposed to the outside of battery 1. The pair of electrode terminals 21 are positioned apart from each other in the lateral direction of battery 1. In addition, an insulating member 22 is provided between each of the electrode terminals 21 and the lid member 5 on the outer surface of the lid member 5. Each of the electrode terminals 21 is electrically insulated from the lid member 5 and the outer container 3 by the insulating member 22, etc.

[0021] Two pairs of leads 23A, 23B and two pairs of clip plates 25A, 25B are arranged in the internal cavity 8 of the outer container 3. Each of the leads 23A, 23B and the clip plates 25A, 25B is formed from a conductive material such as metal. Examples of materials used to form the leads 23A, 23B and the clip plates 25A, 25B include aluminum, stainless steel, copper, and iron. The leads 23A, 23B and the clip plates 25A, 25B are formed separately from each other. In the internal cavity 8, the leads 23A, 23B and the clip plates 25A, 25B are arranged between the electrode groups 2A, 2B and the lid member 5 in the height direction of the battery 1.

[0022] Each of the pair of current-collecting tabs (first current-collecting tabs) 17A of the electrode group 2A is joined to the corresponding one of the pair of leads (first leads) 23A, with the corresponding one of the pair of clip plates (first clip plates) 25A in between. Here, one of the pair of leads 23A is the positive lead (first positive lead), and the other of the pair of leads 23A is the negative lead (first negative lead). Also, one of the pair of clip plates 25A is the positive clip plate (first positive clip plate), and the other of the pair of clip plates 25A is the negative clip plate (first negative clip plate).

[0023] Each of the pair of leads 23A is connected to the corresponding terminal of the pair of electrode terminals 21. Therefore, the positive current collector tab of electrode group 2A (one of 17A) is electrically connected to the positive terminal (one of 21) via the positive clip plate (one of 25A) and the positive lead (one of 23A) in sequence. Then, the negative current collector tab of electrode group 2A (the other one of 17A, opposite to the positive current collector tab) is electrically connected to the negative terminal (the other one of 21, opposite to the positive terminal) via the negative clip plate (the other one of 25A, opposite to the positive clip plate) and the negative lead (the other one of 23A, opposite to the positive lead) in sequence.

[0024] As described above, at least a portion of the electrical path between the positive electrode current collector tab (one of 17A) and the positive electrode terminal (one of 21) of electrode group 2A is formed by the positive electrode clip plate (one of 25A) and the positive electrode lead (one of 23A). Furthermore, at least a portion of the electrical path between the negative electrode current collector tab (the other of 17A) and the negative electrode terminal (the other of 21) of electrode group 2A is formed by the negative electrode clip plate (the other of 25A) and the negative electrode lead (the other of 23A).

[0025] Furthermore, the member forming the electrical path between the positive electrode current collector tab (one of 17A) and the positive electrode terminal (one of 21) of electrode group 2A, such as the positive electrode lead (one of 23A), is positioned away from the member forming the electrical path between the negative electrode current collector tab (the other of 17A) and the negative electrode terminal (the other of 21) of electrode group 2A, such as the negative electrode lead (the other of 23A), in the lateral direction of the battery 1. Therefore, the member forming the electrical path between the positive electrode current collector tab (one of 17A) and the positive electrode terminal (one of 21) of electrode group 2A does not come into contact with the member forming the electrical path between the negative electrode current collector tab (the other of 17A) and the negative electrode terminal (the other of 21) of electrode group 2A.

[0026] Each of the pair of current-collecting tabs (second current-collecting tabs) 17B of the electrode group 2B is joined to the corresponding one of the pair of leads (second leads) 23B, with the corresponding one of the pair of clip plates (second clip plates) 25B in between. Here, one of the pair of leads 23B is the positive lead (second positive lead), and the other of the pair of leads 23B that is not the positive lead is the negative lead (second negative lead). Also, one of the pair of clip plates 25B is the positive clip plate (second positive clip plate), and the other of the pair of clip plates 25B that is not the positive clip plate is the negative clip plate (second negative clip plate).

[0027] Each of the pair of leads 23B is connected to the corresponding terminal of the pair of electrode terminals 21. Thus, the positive current collector tab of electrode group 2B (one of 17B) is electrically connected to the positive terminal (one of 21) via the positive clip plate (one of 25B) and the positive lead (one of 23B) in sequence. The negative current collector tab of electrode group 2B (the other one of 17B from the positive current collector tab) is electrically connected to the negative terminal (the other one of 21 from the positive terminal) via the negative clip plate (the other one of 25B from the positive clip plate) and the negative lead (the other one of 23B from the positive lead) in sequence.

[0028] As described above, at least a portion of the electrical path between the positive electrode current collector tab (one of 17B) and the positive electrode terminal (one of 21) of electrode group 2B is formed by the positive electrode clip plate (one of 25B) and the positive electrode lead (one of 23B). Furthermore, at least a portion of the electrical path between the negative electrode current collector tab (the other of 17B) and the negative electrode terminal (the other of 21) of electrode group 2B is formed by the negative electrode clip plate (the other of 25B) and the negative electrode lead (the other of 23B).

[0029] Furthermore, the member forming the electrical path between the positive electrode current collector tab (one of 17B) and the positive electrode terminal (one of 21) of electrode group 2B, such as the positive electrode lead (one of 23B), is positioned away from the member forming the electrical path between the negative electrode current collector tab (the other of 17B) and the negative electrode terminal (the other of 21) of electrode group 2B, such as the negative electrode lead (the other of 23B), in the lateral direction of the battery 1. Therefore, the member forming the electrical path between the positive electrode current collector tab (one of 17B) and the positive electrode terminal (one of 21) of electrode group 2B does not come into contact with the member forming the electrical path between the negative electrode current collector tab (the other of 17B) and the negative electrode terminal (the other of 21) of electrode group 2B.

[0030] In the battery 1 of this embodiment, as described above, an electrical connection structure of multiple electrode groups 2A and 2B is formed to each of the pair of electrode terminals 21, thereby forming a pair of electrical connection structures. To each of the pair of electrode terminals 21, one corresponding lead (first lead) 23A and one corresponding lead (second lead) 23B are connected together. That is, in each of the pair of electrical connection structures, two (multiple) leads 23A and 23B are connected together to the electrode terminal 21. For example, two positive leads (one of 23A and one of 23B) are connected together to the positive terminal, which is one of the pair of electrode terminals 21, and two negative leads (the other of 23A and the other of 23B) are connected together to the negative terminal, which is the other of the pair of electrode terminals 21.

[0031] Furthermore, a spacer 28 is built into the internal cavity 8 of the outer casing 3. The spacer 28 is made of an electrically insulating material. The spacer 28 is positioned between each of the electrode groups 2A and 2B and the lid member 5 in the height direction of the battery 1. In the internal cavity 8, the spacer 28 prevents contact between the two pairs of current collecting tabs 17A and 17B, the two pairs of leads 23A and 23B, and the two pairs of clip plates 25A and 25B and the outer casing 3 and the lid member 5. As a result, the current collecting tabs 17A and 17B, the leads 23A and 23B, and the clip plates 25A and 25B are electrically insulated from the outer casing 3 and the lid member 5. In addition, the spacer 28 presses each of the electrode groups 2A and 2B toward the side where the bottom wall 6 is located in the height direction of the battery 1. This restricts the movement of each of the electrode groups 2A and 2B along the height direction of the battery 1 in the internal cavity 8.

[0032] In addition, in the example shown in Figures 1 and 2, a safety valve 31 and a liquid filling port (not shown) are formed on the lid member 5. A sealing plate 32 that closes the liquid filling port is then welded to the outer surface of the lid member 5. The safety valve 31 and the liquid filling port are positioned between a pair of electrode terminals 21 in the lateral direction of the battery 1. In one example, the safety valve 31 and the liquid filling port may not be provided on the battery 1.

[0033] The following describes the electrical connection structure of electrode groups 2A and 2B to each of the pair of electrode terminals 21, that is, the aforementioned pair of electrical connection structures. Figures 3 to 5 show the electrical connection structure of multiple electrode groups 2A and 2B to one of the pair of electrode terminals 21 and the configuration of its vicinity, respectively, showing one of the pair of electrical connection structures and the configuration of its vicinity. Figure 3 is a perspective view showing the state in which leads 23A and 23B are not connected to the electrode terminal 21. Figure 4 shows the state of the battery 1 viewed from one side in the depth direction, and Figure 5 shows the state of the battery 1 viewed from one side in the lateral direction.

[0034] Figure 6 also shows one of the pair of leads (first lead) 23A and one of the pair of leads (second lead) 23B. Although Figures 3 to 5 only show the electrical connection structure of the multiple electrode groups 2A and 2B to one of the pair of electrode terminals 21, the electrical connection structure of the multiple electrode groups 2A and 2B to the other of the pair of electrode terminals 21 is the same as the electrical connection structure shown in Figures 3 to 5. Furthermore, although Figures 3 to 6 only show one of the pair of leads 23A and one of the pair of leads 23B, the configuration of the other of the pair of leads 23A and the other of the pair of leads 23B is the same as the configuration shown in Figures 3 to 6.

[0035] As shown in Figures 3 to 5, in each of the pair of electrical connection structures, a clip plate 25A is attached to the protruding end of the current collector tab 17A and its vicinity, and a clip plate 25B is attached to the protruding end of the current collector tab 17B and its vicinity. Each of the pair of clip plates 25A sandwiches a bundled number of strip-shaped portions on the corresponding side of the pair of current collector tabs 17A, and each of the pair of clip plates 25B sandwiches a bundled number of strip-shaped portions on the corresponding side of the pair of current collector tabs 17B. Furthermore, in each of the pair of electrical connection structures, the current collector tabs 17A and 17B are positioned offset from each other in the lateral direction of the battery 1, and the current collector tabs 17A and 17B do not come into contact with each other.

[0036] As shown in Figure 6, each of the pair of leads (first leads) 23A and the pair of leads (second leads) 23B has defined dimensions: a length direction (directions indicated by arrows Y5 and Y6), a width direction (directions indicated by arrows X5 and X6) that intersects (is perpendicular or nearly perpendicular to) the length direction, and a height direction (directions indicated by arrows Z5 and Z6) that intersects (is perpendicular or nearly perpendicular to) both the length and width directions. Each of the leads 23A and 23B also includes a lead base 33, a lead projection 35, and a lead bend 36.

[0037] In each of the leads 23A and 23B, the lead base 33 is formed in a plate shape, and the thickness direction of the lead base 33 coincides with or substantially coincides with the height direction. Each lead base 33 of leads 23A and 23B is provided with a pair of base main surfaces 37 and 38. In each of the leads 23A and 23B, the base main surface (first base main surface) 37 faces one side in the height direction, and the base main surface (second base main surface) 38 faces the opposite side in the height direction from the side that the base main surface 37 faces.

[0038] In each of the leads 23A and 23B, the lead base 33 includes base edge surfaces 41, 42, 45, and 46. In each of the leads 23A and 23B, the base edge surface (first base edge surface) 41 forms one edge in the width direction of the lead base 33, and the base edge surface (second base edge surface) 42 forms the edge of the lead base 33 opposite to the base edge surface 41 in the width direction. Furthermore, in each of the leads 23A and 23B, the base main surfaces 37 and 38 of the lead base 33 extend along the width direction from the base edge surface 41 to the base edge surface 42.

[0039] In each of the leads 23A and 23B, the base edge surface 45 forms one edge in the longitudinal direction on the lead base 33, and the base edge surface 46 forms the edge of the lead base 33 opposite to the base edge surface 45 in the longitudinal direction. In each of the leads 23A and 23B, the base main surfaces 37 and 38 of the lead base 33 extend along the longitudinal direction from the base edge surface 45 to the base edge surface 46.

[0040] Furthermore, in the lead base 33 of each of the leads 23A and 23B, as shown in Figure 5, it is preferable that the boundary between each of the base main surfaces 37 and 38 and the base edge surface 41 be formed in an R shape (chamfered shape), and it is preferable that the boundary between each of the base main surfaces 37 and 38 and the base edge surface 42 be formed in an R shape (chamfered shape). In this case, in the cross-section of the lead base 33 of each of the leads 23A and 23B perpendicular or substantially perpendicular to the longitudinal direction, the boundary between each of the base main surfaces 37 and 38 and the base edge surface 41 is in an arc shape, and the boundary between each of the base main surfaces 37 and 38 and the base edge surface 42 is in an arc shape.

[0041] Furthermore, in each of the leads 23A and 23B, the lead projection 35 protrudes from the base edge surface 46 of the lead base 33 toward one side in the longitudinal direction, and protrudes from the base edge surface 46 toward the side opposite to the side where the base edge surface 45 is located in the longitudinal direction. In each of the leads 23A and 23B, the lead projection 35 is connected to the end of the base edge surface 46 of the lead base 33 on the side where the base edge surface 41 is located. In each of the leads 23A and 23B, the lead projection 35 is formed in a plate shape, and the thickness direction of the lead projection 35 coincides with or approximately coincides with the height direction.

[0042] Furthermore, in each of the leads 23A and 23B, the lead bend portion 36 bends toward the lead projection portion 35 to one side in the height direction, and bends toward the side in the height direction toward the side toward the main base surface 37 of the lead base portion 33. In each of the leads 23A and 23B, the lead bend portion 36 is connected to the end of the lead projection portion 35 opposite to the side toward the base edge surface 41. In each of the leads 23A and 23B, the lead bend portion 36 is formed in a plate shape, and the thickness direction of the lead bend portion 36 coincides with or approximately coincides with the width direction. Also, in each of the leads 23A and 23B, the lead bend portion 36 protrudes toward the side toward the main base surface 37 of the lead base portion 33 and the lead projection portion 35. Furthermore, in each of the leads 23A and 23B, the lead bend portion 36 is positioned at the central position or approximately the central position in the width direction.

[0043] As described above, leads 23A and 23B are formed, so that each of leads 23A and 23B has a T-shape or a nearly T-shape when projected from the length direction. Furthermore, in each of leads 23A and 23B, the cross section perpendicular or nearly perpendicular to the length direction passing through the lead projection 35 and the lead bending portion 36 has an L-shape or a nearly L-shape. In addition, leads 23A and 23B are formed to be the same shape or nearly the same shape with respect to each other.

[0044] In battery 1, each of the leads 23A and 23B is positioned in the internal cavity 8 such that its width coincides with or approximately coincides with the depth of battery 1. In each of the leads 23A and 23B positioned in the internal cavity 8, its length coincides with or approximately coincides with the lateral direction of battery 1, and its height coincides with or approximately coincides with the height of battery 1.

[0045] In each of the leads 23A and 23B positioned in the internal cavity 8, the main base surface (first main base surface) 37 of the lead base 33 faces the side where the lid member 5 is located, with respect to the height direction of the battery 1. Furthermore, in each of the leads 23A and 23B, the main base surface (second main base surface) 38 of the lead base 33 faces the side where the electrode groups 2A and 2B are located, with respect to the height direction of the battery 1. In one example, in each of the leads 23A and 23B, the main base surfaces 37 and 38 are parallel or approximately parallel to the depth and lateral directions of the battery 1, and parallel or approximately parallel to the inner and outer surfaces of the lid member 5. In this case, in each of the leads 23A and 23B, the main base surfaces 37 and 38 are perpendicular or approximately perpendicular to the height direction of the battery 1.

[0046] As described above, since leads 23A and 23B are arranged in the internal cavity 8, at the base rim 33 of each lead 23A and 23B, the base edge surface (first base edge surface) 41 forms one edge in the depth direction of the battery 1, and the base edge surface (second base edge surface) 42 forms the edge opposite to the base edge surface 41 in the depth direction of the battery 1. Furthermore, at the base rim 33 of each lead 23A and 23B, the base edge surface 45 forms one edge in the lateral direction of the battery 1, and the base edge surface 46 forms the edge opposite to the base edge surface 45 in the lateral direction of the battery 1.

[0047] In each of the pair of electrical connection structures, a current collector tab (first current collector tab) 17A is joined to the lead base (first lead base) 33 of lead 23A, and a current collector tab (second current collector tab) 17B is joined to the lead base (second lead base) 33 of lead 23B. In this embodiment, in each of the leads 23A, a joining portion is formed on the main base surface 37 of the lead base 33 with the corresponding one of the current collector tabs 17A. And in each of the leads 23B, a joining portion is formed on the main base surface 37 of the lead base 33 with the corresponding one of the current collector tabs 17B.

[0048] Furthermore, in each of the pair of electrical connection structures, leads 23A and 23B are positioned offset from each other in the lateral direction of the battery 1. In each of the pair of electrical connection structures, the lead base 33 of lead 23A is located on the opposite side of the electrode terminal 21 from the lead base 33 of lead 23B in the lateral direction of the battery 1. Therefore, in each of the pair of electrical connection structures, the connection portion of the current collecting tab 17A to the lead base 33 of lead 23A is located on the opposite side of the electrode terminal 21 from the connection portion of the current collecting tab 17B to the lead base 33 of lead 23B.

[0049] Furthermore, in each of the pair of electrical connection structures, the lead protrusion (first lead protrusion) 35 and lead bend (first lead bend) 36 of lead 23A are not misaligned or are almost misaligned with respect to the lead protrusion (second lead protrusion) 35 and lead bend (second lead bend) 36 of lead 23B in the lateral direction of battery 1. In each of the pair of electrical connection structures, the lead protrusions 35 and lead bends 36 of leads 23A and 23B are not misaligned or are almost misaligned with respect to the electrode terminal 21 in the lateral direction of battery 1. In each of the pair of electrical connection structures, the lead protrusion 35 of lead (first lead) 23A protrudes toward lead 23B in the lateral direction of battery 1. In each of the pair of electrical connection structures, the lead protrusion 35 of lead (second lead) 23B protrudes toward lead 23A in the lateral direction of battery 1.

[0050] Furthermore, in each of the leads 23A and 23B positioned in the internal cavity 8, the lead bend portion 36 bends toward the side where the lid member 5 is located in the height direction of the battery 1, relative to the lead protrusion portion 35. Therefore, in each of the pair of electrical connection structures, in each of the leads 23A and 23B, the lead bend portion 36 protrudes toward the side where the lid member 5 is located, relative to the lead base portion 33 and the lead protrusion portion 35. In each of the pair of electrical connection structures, each of the leads 23A and 23B is connected to the electrode terminal 21 at the lead bend portion 36. And in each of the pair of electrical connection structures, the connection portion of the current collection tab 17A of lead 23A to the lead base portion 33 is located on the opposite side from the connection portion of the current collection tab 17B of lead 23B to the lead base portion 33, relative to the connection portions of leads 23A and 23B to the electrode terminal 21.

[0051] Furthermore, in each of the pair of electrical connection structures, the lead bend portion (second lead bend portion) 36 of lead 23B is adjacent to the lead bend portion (first lead bend portion) 36 of lead 23A, from one side in the depth direction of the battery 1. In each of the pair of electrical connection structures, the lead bend portions 36 of leads 23A and 23B are located between the lead protrusion 35 of lead 23A and the lead protrusion 35 of lead 23B in the depth direction of the battery 1. Also, in each of the pair of electrical connection structures, lead 23B is positioned at a location where lead 23A is rotated 180° or approximately 180° around the central axis of the electrode terminal 21. Therefore, in each of the pair of electrical connection structures, leads 23A and 23B are arranged symmetrically or approximately symmetrically with respect to each other around the central axis of the electrode terminal 21. Note that the central axes of each electrode terminal 21 are aligned with the height direction of the battery 1.

[0052] As described above, in this embodiment, in each of the pair of electrical connection structures, the current-collecting tab (first current-collecting tab) 17A of the electrode group (first electrode group) 2A is joined to the lead (first lead) 23A, and the current-collecting tab (second current-collecting tab) 17B of the electrode group (second electrode group) 2B is connected to a lead (second lead) 23B that is separate from the lead 23A. In each of the electrical connection structures, leads 23A and 23B are connected together to the electrode terminal 21. With this configuration, the amount of current flowing through each of the leads 23A and 23B can be reduced compared to configurations in which the current-collecting tabs of multiple electrode groups are joined together to a single lead, making it possible to reduce the thickness of each of the leads 23A and 23B. As the thickness of each of the leads 23A and 23B is reduced, the space occupied by connecting members such as leads 23A and 23B in the internal cavity 8 becomes smaller, making it possible to increase the space occupied by multiple electrode groups 2A and 2B. This makes it possible to increase the capacity of electrode groups 2A and 2B without increasing the size of battery 1.

[0053] Furthermore, the process of joining each of a pair of current-collecting tabs 17A to the corresponding lead 23A by ultrasonic welding, and the process of joining each of a pair of current-collecting tabs 17B to the corresponding lead 23B by ultrasonic welding, etc., is advantageous compared to the process of joining current-collecting tabs of multiple electrode groups together to a single lead, as it reduces damage to the current-collecting tabs, improves the joint strength, and reduces the thickness of the lead plate, thus improving ease of assembly. As a result, by configuring each of the pair of electrical connection structures as described above, ease of assembly is improved in the process of forming the electrical connection structures.

[0054] Furthermore, in each of the pair of leads 23A, one corresponding tab of the pair of current-collecting tabs 17A is joined to the main base surface 37 of the lead base 33, and the main base surface 37 faces the side where the cover member 5 is located. Similarly, in each of the pair of leads 23B, one corresponding tab of the pair of current-collecting tabs 17B is joined to the main base surface 37 of the lead base 33, and the main base surface 37 faces the side where the cover member 5 is located. Due to the above configuration, even if the dimensions of each of the leads 23A and 23B along the height direction of the battery 1 are reduced, the joining area with the corresponding one of the current-collecting tabs 17A and 17B of each lead 23A and 23B is adequately secured, and the corresponding one of the current-collecting tabs 17A and 17B is properly joined to each of the leads 23A and 23B. As the dimensions of each lead 23A and 23B along the height direction of the battery 1 are reduced, the space occupied by leads 23A and 23B in the internal cavity 8 is further reduced, making it possible to further increase the space occupied by the multiple electrode groups 2A and 2B in the internal cavity 8.

[0055] Furthermore, in each of the pair of electrical connection structures, the current collector tabs 17A and 17B are positioned offset from each other in the lateral direction of the battery 1. In each of the pair of electrical connection structures, the connection portion of the current collector tab 17A to the lead base 33 of the lead 23A is located on the opposite side of the connection portion of the current collector tab 17B to the lead base 33 of the lead 23B from the connection portion of the leads 23A and 23B to the electrode terminal 21. This configuration makes it easier to connect each of the pair of current collector tabs 17A to the corresponding one of the pair of leads 23A, and to connect each of the pair of current collector tabs 17B to the corresponding one of the pair of leads 23B.

[0056] Furthermore, in each of the leads 23A and 23B, the lead bend portion 36 bends toward the lead projection portion 35 toward the side where the cover member 5 is located, in the height direction of the battery 1. In each of the pair of electrical connection structures, each of the leads 23A and 23B is connected to the electrode terminal 21 at the lead bend portion 36, and the lead bend portion 36 of lead 23B is adjacent to the lead bend portion 36 of lead 23A from one side in the thickness direction of the battery 1. With this configuration, even though leads 23A and 23B are separate components in each of the pair of electrical connection structures, it becomes easier to connect leads 23A and 23B together to the electrode terminal 21.

[0057] Furthermore, in each of the leads 23A and 23B, the boundary between the base main surfaces 37 and 38 and the base edge surface 41 is rounded in shape, and the boundary between the base main surfaces 37 and 38 and the base edge surface 42 is also rounded in shape. As a result, in each of the pair of electrical connection structures, damage to the current collection tab 17A caused by contact of the current collection tab 17A with the lead 23A is effectively prevented. Similarly, in each of the pair of electrical connection structures, damage to the current collection tab 17B caused by contact of the current collection tab 17B with the lead 23B is effectively prevented. As a result, the vibration resistance and other properties of the battery 1 product are improved.

[0058] (modified version) In the first modified example shown in Figure 7, in each of the pair of electrical connection structures, the lead base (first lead base) 33 of lead 23A is joined to the current collecting tab (first current collecting tab) 17A, and the lead base (second lead base) 33 of lead 23B is joined to the current collecting tab (second current collecting tab) 17B. However, in this modified example, in each of the leads 23A, a connection portion is formed on the main base surface (second main base surface) 38 of the lead base 33 with the corresponding one of the current collecting tabs 17A. And in each of the leads 23B, a connection portion is formed on the main base surface (second main base surface) 38 of the lead base 33 with the corresponding one of the current collecting tabs 17B. In this modified example as well, in each of the lead bases 33 of leads 23A and 23B, the main base surface 38 faces the side where the electrode groups 2A and 2B are located, with respect to the height direction of the battery 1. Here, Figure 7 shows the battery 1 as viewed from one side in the depth direction.

[0059] As described above, in this modified example, one corresponding current-collecting tab 17A, 17B is joined to the base main surface 38 of each lead 23A, 23B, which faces the side where the electrode groups 2A, 2B are located. With this configuration, even if the dimensions of each lead 23A, 23B along the height direction of the battery 1 are reduced, the joining area with the corresponding current-collecting tab 17A, 17B of each lead 23A, 23B is adequately secured, and one corresponding current-collecting tab 17A, 17B is properly joined to each lead 23A, 23B. Therefore, as the dimensions of each lead 23A, 23B along the height direction of the battery 1 are reduced, the space occupied by leads 23A, 23B in the internal cavity 8 is reduced, making it possible to increase the space occupied by the multiple electrode groups 2A, 2B in the internal cavity 8, similar to the embodiments described above.

[0060] Furthermore, in one modified example, in at least one of the pair of electrical connection structures, one of the current-collecting tabs 17A, 17B is joined to the base main surface 37 of the lead (corresponding one of 23A, 23B), and the other of the current-collecting tabs 17A, 17B is joined to the base main surface 38 of the lead (corresponding one of 23A, 23B). Even with this configuration, as in the embodiments described above, it is possible to reduce the space occupied by the leads 23A, 23B in the internal cavity 8 while appropriately securing the joining area between each lead 23A, 23B and its corresponding current-collecting tab 17A, 17B. As a result, in this modified example as well, it is possible to increase the space occupied by the multiple electrode groups 2A, 2B in the internal cavity 8.

[0061] Furthermore, in the second modified example shown in Figure 8, bellows structures 51 and 52 are formed on each of the leads 23A and 23B. On each of the leads 23A and 23B, a bellows structure (first bellows structure) 51 is formed on the lead protrusion 35. On each of the leads 23A and 23B, the bellows structure 51 allows the lead protrusion 35 to expand and contract in the lateral direction of the battery 1 (the length direction of the lead). On each of the leads 23A and 23B, the bellows structure 51 allows the lead protrusion 35 to vibrate in the height direction of the battery 1 (the height direction of the lead). In addition, on each of the leads 23A and 23B, a bellows structure (second bellows structure) 52 is formed on the lead bend 36. On each of the leads 23A and 23B, the bellows structure 52 allows the lead bend 36 to expand and contract in the height direction of the battery 1 (the height direction of the lead). Furthermore, in each of the leads 23A and 23B, the bellows structure 52 allows the lead bend portion 36 to vibrate in the depth direction of the battery 1 (the width direction of the lead). In this modified example, the lead bend portion 36 is formed integrally with the lead protrusion portion 35. However, the region of the lead protrusion portion 35 where the bellows structure 51 is formed is not connected to the lead bend portion 36, and there is a gap between it and the lead bend portion 36. Also, the lead bend portion 36 is not connected to the base edge surface 46 of the base portion 33, and there is a gap between it and the base edge surface 46. In this modified example, the same functions and effects as in the embodiments described above are achieved.

[0062] Furthermore, in this modified example, vibrations caused by external shocks to the battery 1 are absorbed by the expansion and contraction and vibration of the bellows structures 51 and 52 of the leads 23A and 23B. As a result, the vibration resistance of each of the leads 23A and 23B is improved. In addition, since the directions in which each of the leads 23A and 23B is prone to expansion and contraction and vibration are different for the two bellows structures 51 and 52, vibrations are appropriately absorbed regardless of the direction of vibration. Therefore, the vibration resistance of each of the leads 23A and 23B is further improved. Note that in one modified example, only one of the bellows structures 51 or 52 may be provided for each of the leads 23A and 23B.

[0063] In the third modified example shown in Figure 9, a through hole 53 is formed in each of the pair of electrode terminals 21. Each through hole 53 penetrates the corresponding electrode terminal 21 in the height direction of the battery 1. In each of the electrode terminals 21, one end of the through hole 53 opens to the outside of the battery 1, and the other end of the through hole 53 opens to the internal cavity 8. In each of the pair of electrical connection structures, the lead bend portion (first lead bend portion) 36 of the lead (first lead) 23A and the lead bend portion (second lead bend portion) 36 of the lead (second lead) 23B are inserted together from the internal cavity 8 into the through hole 53 of the electrode terminal 21. Then, in each of the pair of electrical connection structures, the lead bend portions 36 of leads 23A and 23B are connected to the electrode terminal 21 while inserted into the through hole 53. Here, Figure 9 shows the battery 1 as viewed from one side in the lateral direction, with a portion of it shown in a cross-section perpendicular or nearly perpendicular to the lateral direction.

[0064] In this modified example, in each of the electrical connection structures, the respective lead bends 36 of leads 23A and 23B are joined to the circumferential surface of the through hole 53 by laser welding or the like, thereby connecting leads 23A and 23B together to the electrode terminal 21. By forming through holes 53 in each of the electrode terminals 21, it becomes easier to join the respective lead bends 36 of leads 23A and 23B to the circumferential surface of the through hole 53 when forming each of the electrical connection structures. This improves the work efficiency of forming each of the electrical connection structures. This modified example also provides the same effects and advantages as the embodiments described above.

[0065] Furthermore, in one modified example, the clip plates 25A and 25B may not be provided. In this case, in each of the pair of electrical connection structures, the current collector tab (first current collector tab) 17A is directly joined to one of the base main surfaces 37, 38 of the lead (first lead) 23A, and the current collector tab (second current collector tab) 17B is directly joined to one of the base main surfaces 37, 38 of the lead (second lead) 23B.

[0066] Furthermore, the number of electrode groups housed in the internal cavity 8 is not limited to two; there may be multiple. In one modified example, three or more electrode groups are housed in the internal cavity 8. In this case as well, in each of the pair of electrical connection structures, the current-collecting tab (first current-collecting tab) of the first electrode group, which is one of the three or more electrode groups, is joined to the first lead, and the current-collecting tab (second current-collecting tab) of the second electrode group, which is one of the three or more electrode groups separate from the first electrode group, is joined to a second lead separate from the first lead. In each of the electrical connection structures, the first lead and the second lead are connected together to the electrode terminal. With this configuration, in each of the electrical connection structures, it becomes possible to reduce the thickness of each lead plate compared to configurations where the current-collecting tabs of the first electrode group and the second electrode group are joined together to a single lead. As a result, similar to the embodiments described above, the space occupied by connecting members such as leads in the internal cavity 8 can be reduced, and the space occupied by multiple electrode groups can be increased.

[0067] Furthermore, when three or more electrode groups are housed in the internal cavity 8, it is preferable that each of the pair of electrical connection structures has the same number of leads as the electrode groups, provided separately from each other. In this case, each of the pair of electrical connection structures has a different lead connected to each current-collecting tab. And in each of the electrical connection structures, the same number of leads as the electrode groups are connected together to one electrode terminal.

[0068] Furthermore, in the embodiments described above, the electrical connection structure with the positive terminal and the electrical connection structure with the negative terminal are similar in configuration to each other, but this is not the only possible configuration. In some modifications, only one of the pair of electrical connection structures may be formed in the same manner as in any of the embodiments described above. That is, it is sufficient that at least one of the pair of electrical connection structures is formed in the same manner as in the embodiments described above.

[0069] According to at least one embodiment or example, the first current-collecting tab of a first electrode group, which is one of a plurality of electrode groups, is connected to a first lead, and the second current-collecting tab of a second electrode group, which is one of the plurality of electrode groups separate from the first electrode group, is connected to a second lead separate from the first lead. The first lead and the second lead are then connected together to the electrode terminals. This makes it possible to provide a battery in which the space occupied by the plurality of electrode groups in the internal cavity of the outer container can be increased, in a configuration in which the current-collecting tabs of the plurality of electrode groups protrude toward the side where the lid member is located.

[0070] While several embodiments of the present invention have been described, these embodiments are presented as examples only and are not intended to limit the scope of the invention. These novel embodiments can be carried out in a variety of other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their variations are included in the scope and spirit of the invention, as well as in the claims of the invention and its equivalents. [Explanation of Symbols]

[0071] 1...Battery, 2A...Electrode group (first electrode group), 2B...Electrode group (second electrode group), 3...Outer container, 5...Lid member, 6...Bottom wall, 7...Surface wall, 15...Positive electrode, 16...Negative electrode, 17A...Current collector tab (first current collector tab), 17B...Current collector tab (second current collector tab), 21...Electrode terminal, 23A...Lead (first lead), 23B...Lead (second lead) 33...Lead base, 35...Lead projection, 36...Lead bend, 37...Main base surface (first main base surface), 38...Main base surface (second main base surface), 41...Base edge surface (first main base surface), 42...Base edge surface (second main base surface), 51...Bellows structure (first bellows structure), 52...Bellows structure (second bellows structure), 53...Through hole.

Claims

1. an outer container having a bottom wall and a peripheral wall, and an internal cavity formed therein that opens to the side opposite to the side where the bottom wall is located in the height direction; a cover member attached to the peripheral wall of the outer container in a state of closing the opening of the internal cavity; a plurality of electrode groups each including a positive electrode and a negative electrode and housed in the internal cavity of the outer container; a first current collecting tab protruding toward a side where the cover member is located in a first electrode group that is one of the plurality of electrode groups; a second current collecting tab protruding toward a side where the cover member is located in a second electrode group that is one of the plurality of electrode groups and is different from the first electrode group; a first lead to which the first current collecting tab is joined; a second lead formed separately from the first lead and to which the second current collecting tab is joined; an electrode terminal exposed to the outside on the outer surface of the lid member and to which the first lead and the second lead are connected; A battery comprising:

2. each of the first lead and the second lead includes a lead base; the lead base of each of the first lead and the second lead includes a first base main surface facing a side on which the lid member is located in the height direction, and a second base main surface facing a side on which the electrode group is located in the height direction; the first current collecting tab is joined to the first base main surface or the second base main surface of the lead base in the first lead; the second current collecting tab is joined to the first base main surface or the second base main surface of the lead base of the second lead; 10. The battery of claim 1.

3. the first electrode group and the second electrode group are arranged side by side in a depth direction that intersects with the height direction, the first current collecting tab and the second current collecting tab are arranged to be shifted from each other in a lateral direction that intersects both the height direction and the depth direction, a joining portion of the first current collecting tab to the lead base of the first lead is located on an opposite side to a joining portion of the second current collecting tab to the lead base of the second lead with respect to a connection portion of the first lead and the second lead to the electrode terminal; 3. The battery of claim 2.

4. the first lead includes a first lead protruding portion protruding from the lead base toward the second lead in the lateral direction, and a first lead bent portion bent relative to the first lead protruding portion toward a side where the lid member is located, the second lead includes a second lead protruding portion protruding from the lead base toward the first lead in the lateral direction, and a second lead bent portion bent relative to the second lead protruding portion toward a side where the lid member is located and adjacent to the first lead bent portion of the first lead from one side in the depth direction, the first lead is connected to the electrode terminal at the first lead bent portion; the second lead is connected to the electrode terminal at the second lead bent portion; 4. The battery of claim 3.

5. 5. The battery of claim 4, wherein the first lead protrusion of the first lead and the second lead protrusion of the second lead each have a first bellows structure that is expandable and contractible in the lateral direction and vibrable in the vertical direction.

6. 6. The battery of claim 4, wherein the first lead bend portion of the first lead and the second lead bend portion of the second lead each have a second bellows structure that is expandable and contractable in the height direction and vibrable in the depth direction.

7. a through hole penetrating the electrode terminal in the height direction is formed in the electrode terminal; the first lead bent portion of the first lead and the second lead bent portion of the second lead are connected to the electrode terminal in a state where they are inserted from the internal cavity into the through hole of the electrode terminal; 7. The battery of claim 4.

8. The lead base of each of the first lead and the second lead includes: a first base edge surface that forms an edge on one side of the lead base in a depth direction that intersects with the height direction, and in which boundaries between the first base main surface and the second base main surface are formed in an R-shape; a second base edge surface that forms an edge of the lead base opposite to the first base edge surface in the depth direction, and has a boundary between the first base main surface and the second base main surface that is formed in an R-shape; 8. The battery of claim 2, comprising:

9. the first current collecting tabs include a first positive electrode current collecting tab that protrudes toward a side of the first electrode group where the cover member is located, and a first negative electrode current collecting tab that is provided apart from the first positive electrode current collecting tab and that protrudes toward a side of the first electrode group from which the first positive electrode current collecting tab protrudes, the second current collecting tabs include a second positive electrode current collecting tab that protrudes toward a side of the second electrode group where the cover member is located, and a second negative electrode current collecting tab that is provided apart from the second positive electrode current collecting tab and that protrudes toward a side of the second electrode group from which the second positive electrode current collecting tab protrudes, the first lead includes a first positive electrode side lead to which the first positive electrode current collecting tab is joined, and a first negative electrode side lead to which the first negative electrode current collecting tab is joined, the second lead includes a second positive electrode side lead to which the second positive electrode current collecting tab is joined, and a second negative electrode side lead to which the second negative electrode current collecting tab is joined, The electrode terminals include a positive electrode terminal to which the first positive electrode lead and the second positive electrode lead are connected together, and a negative electrode terminal that is disposed on the outer surface of the lid member and spaced apart from the positive electrode terminal, and to which the first negative electrode lead and the second negative electrode lead are connected together.

9. The battery of claim 1.

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