WO2020026346A1

WO2020026346A1 - Secondary battery and battery pack

Info

Publication number: WO2020026346A1
Application number: PCT/JP2018/028675
Authority: WO
Inventors: 博清間明田; 直樹岩村; 元気山岸
Original assignee: 株式会社東芝
Priority date: 2018-07-31
Filing date: 2018-07-31
Publication date: 2020-02-06
Also published as: JP6989706B2; JPWO2020026346A1

Abstract

In this secondary battery, a first outer member has a housing space defined by a bottom wall and side walls and comprises a flange that protrudes from the rim of an opening in the housing space, towards the outer circumferential side relative to the side walls. The housing space has an electrode group housed therein and a second outer member faces the flange. A welded section welds the flange and the second outer member, at a section that protrudes towards the outer circumferential side from the rim of the opening, and a release valve is provided in a side wall. In the protruding section protruding from the rim of the opening towards the outer circumferential side, the flange and the second outer member are folded together in a folded section. The folded section is provided at least across a range in which the release valve is positioned in the circumferential direction of the opening.

Description

Rechargeable battery and battery pack

The embodiment of the present invention relates to a secondary battery and a battery pack.

Generally, a secondary battery includes an electrode group including a positive electrode and a negative electrode, and an exterior part that houses the electrode group. In some secondary batteries, the exterior part is formed of two exterior members, and each of the two exterior members is formed of a metal such as stainless steel. In this secondary battery, the first exterior member, which is one of the exterior members, is formed in a bottomed cylindrical shape having a bottom wall and side walls, and the bottom wall and the side walls define a storage space for housing the electrode group. You. The storage space has an opening on the side opposite to the bottom wall. Further, in the first exterior member, a flange is formed at a portion opposite to the bottom wall, and the flange defines an opening edge of an opening of the storage space. In this secondary battery, the second exterior member is arranged to face the flange and closes the opening of the storage space. The flange and the second exterior member protrude from the opening edge toward the outer periphery with respect to the side wall. A welded portion to which the flange and the second exterior member are hermetically welded is formed on a protruding portion of the flange and the second exterior member on the outer peripheral side. The weld is formed continuously over the entire circumference of the opening. The storage space is sealed from the outside by the welded portion.

がある Some secondary batteries are provided with an open valve on the exterior. In such a secondary battery, the opening valve is opened when the internal pressure of the storage space for storing the electrode group, that is, the internal pressure of the exterior part becomes equal to or higher than a predetermined value. When the release valve is opened, gas is discharged from the storage space inside the exterior part to the outside of the exterior part via the release valve.

では In the secondary battery provided with the open valve as described above, the open valve is formed with a thin portion having a smaller thickness than other portions of the exterior portion. Since the thin portion is formed, the release valve has low resistance to an external impact. Therefore, even when the internal pressure of the storage space is smaller than the predetermined value, the opening valve may be damaged by an external impact such as an impact due to physical contact. For this reason, it is required that the opening valve be appropriately protected against an external impact or the like.

International Publication No. WO 2016/204147 JP 2001-266804 A JP-A-2001-345083

The problem to be solved by the present invention is to provide a secondary battery in which an opening valve provided in an exterior part is appropriately protected, and a battery pack including the secondary battery.

According to the embodiment, the secondary battery includes the first exterior member, the second exterior member, the electrode group, and the release valve. The first exterior member has a bottom wall and a side wall, and is formed of metal. In the first exterior member, a storage space is defined by the bottom wall and the side wall, and the storage space has an opening on a side opposite to the bottom wall. The first exterior member includes a flange protruding from the opening edge of the opening to the outer peripheral side with respect to the side wall. The electrode group includes a positive electrode and a negative electrode, and is housed in a housing space. The second exterior member is formed of metal and is arranged to face the flange, and closes the opening of the storage space. The welding portion welds the flange and the second exterior member over the entire periphery of the opening at a portion protruding from the opening edge to the outer peripheral side to seal the storage space. The release valve is provided on a side wall of the first exterior member, and is opened when an internal pressure of the storage space becomes a predetermined value or more. The flange and the second exterior member are bent together at a bent portion provided at a portion protruding from the opening edge toward the outer peripheral side. The bent portion is provided at least in a circumferential direction of the opening over a range する where the opening valve is located. Due to the bent portion, the extending portion from the bent portion to each outer edge of the flange and the second exterior member is located on the outer peripheral side with respect to the release valve.

FIG. 1 is a perspective view schematically showing the secondary battery according to the first embodiment. FIG. 2 is a perspective view schematically showing the first exterior member, the second exterior member, and the electrode group according to the first embodiment in an exploded state with respect to each other. FIG. 3 is a schematic diagram illustrating the secondary battery according to the first embodiment when viewed from the side where the bottom wall is located in the thickness direction. FIG. 4 is a schematic diagram illustrating the secondary battery according to the first embodiment when viewed from one side in the vertical direction. FIG. 5 is a schematic diagram illustrating the secondary battery according to the first embodiment when viewed from one side in the lateral direction. FIG. 6 is a schematic diagram illustrating the configuration of the electrode group according to the first embodiment. FIG. 7 is a schematic diagram showing an electrical connection configuration between the electrode group and one of the pair of terminals in the first embodiment. FIG. 8 is a cross-sectional view of the secondary battery according to the first embodiment, showing one of a pair of side walls along the lateral direction and a configuration of a protruding portion from the side walls to the outer peripheral side, which is perpendicular or substantially perpendicular to the lateral direction. And it is sectional drawing shown roughly by the cross section which passes an opening valve. FIG. 9 is a schematic diagram showing the configuration of the opening valve and its vicinity on the inner surface of the side wall of the secondary battery according to the first embodiment. FIG. 10 is a schematic view showing a state where a weld is formed in the manufacture of the secondary battery according to the first embodiment. FIG. 11 is a schematic view showing a state in which the flange and the second exterior member are cut at a position on the outer peripheral side with respect to the welded portion from the state of FIG. 10 and the outer peripheral side is trimmed from the cut position. FIG. 12 is a schematic view showing a bending line when forming a bent portion from the state of FIG. FIG. 13 is a schematic diagram illustrating the secondary battery according to the first modification in a state where the secondary battery is viewed from the side where the bottom wall is located in the thickness direction. FIG. 14 is a schematic diagram showing a secondary battery according to a first modification viewed from one side in a vertical direction. FIG. 15 is a schematic view showing a secondary battery according to a first modification in a state viewed from one lateral side. FIG. 16 is a perspective view schematically showing a secondary battery according to a second modification. FIG. 17 is a schematic diagram illustrating a secondary battery according to a second modification when viewed from one side in the vertical direction. FIG. 18 is a cross-sectional view of a secondary battery according to a second modification, in which one of a pair of side walls along the lateral direction and a configuration of a protruding portion from the side wall to the outer peripheral side are vertically or substantially perpendicularly to the lateral direction. And it is sectional drawing shown roughly by the cross section which passes an opening valve. FIG. 19 shows that in the secondary battery according to the third modification, one of the pair of side walls along the lateral direction and the configuration of the protruding portion from the side wall to the outer peripheral side are vertically or substantially perpendicularly to the lateral direction. And it is sectional drawing shown roughly by the cross section which passes an opening valve. FIG. 20 is a schematic diagram showing the configuration of the opening valve and its vicinity on the outer surface of the side wall of the secondary battery according to the third modification. FIG. 21 is a perspective view schematically showing a secondary battery according to a fourth modification. FIG. 22 is a perspective view schematically showing a part of a battery pack including a plurality of secondary batteries according to the fourth modification. FIG. 23 is a perspective view schematically showing a secondary battery according to a fifth modification.

Hereinafter, embodiments will be described with reference to FIGS. 1 to 23.

(First embodiment)
FIG. 1 shows the secondary battery 1 according to the first embodiment, and FIG. 2 shows the secondary battery 1 in a state where it is disassembled for each member. The secondary battery 1 is, for example, a non-aqueous electrolyte battery. As shown in FIGS. 1 and 2, the secondary battery 1 includes an exterior unit 3. The exterior part 3 is formed from a first exterior member 5 and a second exterior member 6. Each of the

exterior members

5 and 6 is formed from a metal such as stainless steel. Examples of the metal other than stainless steel forming the

exterior members

5 and 6 include aluminum, aluminum alloy, iron, and plated steel. The first exterior member 5 is formed in a cylindrical shape with a bottom. In the present embodiment, the first exterior member 5 has a bottom wall 7 and two pairs of

side walls

8A, 8B, 9A, 9B, and is formed in a substantially rectangular cylindrical shape with a bottom. In the first exterior member 5, the storage space 11 is defined by the bottom wall 7 and the

side walls

8A, 8B, 9A, 9B. The electrode group 10 is stored in the storage space 11.

The storage space 11 has an opening 12 on the side opposite to the bottom wall 7. Here, in the secondary battery 1, the vertical direction (the direction indicated by the arrow X1 and the arrow X2), the horizontal direction intersecting the vertical direction (the direction indicated by the arrow Y1 and the arrow Y2), and the vertical direction and the horizontal direction. A thickness direction (direction indicated by arrows Z1 and Z2) that intersects both is defined. In the secondary battery 1 of the present embodiment, the horizontal direction is vertical or substantially vertical to the vertical direction, and the thickness direction is vertical or substantially vertical to both the vertical direction and the horizontal direction. In the secondary battery 1, each of the pair of side walls (first side walls) 8A and 8B extends in the vertical direction, and each of the pair of side walls (second side walls) 9A and 9B extends in the horizontal direction. It is extended along. The

side walls

8A and 8B face each other and are arranged laterally away from each other with the storage space 11 interposed therebetween. Further, the

side walls

9A and 9B face each other and are arranged vertically apart from each other with the storage space 11 interposed therebetween. Each of the

side walls

8A, 8B, 9A, and 9B extends from the bottom wall 7 toward the opening 12 along the thickness direction, and the storage space 11 has one side of the opening 12 in the thickness direction (arrow Z2). Side). The opening surface of the opening 12 is a surface parallel or substantially parallel to the vertical and horizontal directions of the secondary battery 1.

FIG. 3 shows the secondary battery 1 as viewed from the side where the bottom wall 7 is located (the arrow Z1 side) in the thickness direction. FIG. 4 shows the secondary battery 1 viewed from one side in the vertical direction (arrow X2 side), and FIG. 5 shows the secondary battery 1 from one side in the horizontal direction (arrow Y1 side). It is shown in a state where it is seen. As shown in FIGS. 1 to 5, in the first exterior member 5, a flange 13 is provided at a portion opposite to the bottom wall 7. The flange 13 defines an opening edge 15 of the opening 12 over the entire circumference in the circumferential direction of the opening 12. The flange 13 projects from the opening edge 15 to the outer periphery over the entire circumference in the circumferential direction of the opening 12. For this reason, the flange 13 protrudes from the

side walls

8A, 8B, 9A, 9B on a side away from the opening 12 in a direction parallel to the opening surface of the opening 12.

In the present embodiment, the opening edge 15 has a pair of first opening edges 16A and 16B along the vertical direction and a pair of second opening edges 17A and 17B along the horizontal direction. The opening 12 is formed in a rectangular shape or a substantially rectangular shape. In addition, the shape of the opening 12 is not limited to a rectangular shape, and the opening 12 may be formed in, for example, a polygonal shape other than a rectangular shape or an elliptical shape.

The flange 13 has an outer edge (flange outer edge) 51. The outer edge 51 is continuous over the entire circumference in the circumferential direction of the opening 12. The outer edge 51 has a pair of first flange

outer edges

52A and 52B along the vertical direction and a pair of second flange

outer edges

53A and 53B along the horizontal direction. The first flange outer edge 52A forms an outer edge of the flange 13 at a portion protruding from the first opening edge 16A and the side wall 8A to the outer peripheral side, and the first flange outer edge 52B is formed by the first opening edge 16B and the side wall. An outer edge of the flange 13 is formed at a portion protruding from 8B to the outer peripheral side. The second flange outer edge 53A forms an outer edge of the flange 13 at a portion protruding outward from the second opening edge 17B and the side wall 9B, and the second flange outer edge 53B is formed with the second opening edge 17B and the side wall. An outer edge of the flange 13 is formed at a portion protruding from 9B to the outer peripheral side.

外 The outer edge 51 of the flange 13 has relay outer edges (flange relay outer edges) 55A to 55D. The relay outer edge 55A extends continuously from the first flange outer edge 52A to the second flange outer edge 53A, and the relay outer edge 55B extends continuously from the first flange outer edge 52A to the second flange outer edge 53B. Is done. Further, the relay outer edge 55C extends continuously from the first flange outer edge 52B to the second flange outer edge 53A, and the relay outer edge 55D continuously extends from the first flange outer edge 52B to the second flange outer edge 53B. It is extended. That is, each of the relay outer edges 55A to 55D extends continuously from a corresponding one of the pair of first flange

outer edges

52A, 52B to a corresponding one of the pair of second flange

outer edges

53A, 53B. In addition, each of the relay outer edges 55A to 55D forms an obtuse angle at the intersection with the corresponding one of the pair of first flange

outer edges

52A and 52B. Each of the relay outer edges 55A to 55D forms an obtuse angle at the intersection with the corresponding one of the pair of second flange

outer edges

53A and 53B.

In the present embodiment, the second exterior member 6 is a plate-shaped member, and is formed, for example, in a substantially rectangular shape. The second exterior member 6 is arranged to face the flange 13 and is attached to the flange 13 from the side where the opening 12 opens. In the present embodiment, the second exterior member 6 projects from the opening edge 15 to the outer peripheral side over the entire circumference of the opening 12 in the circumferential direction. Therefore, the second exterior member 6 protrudes from the

side walls

8A, 8B, 9A, 9B on a side away from the opening 12 in a direction parallel to the opening surface of the opening 12. In the region on the outer peripheral side from the opening edge 15, the second exterior member 6 faces the flange 13 over the entire circumference of the opening 12 in the circumferential direction. Further, the second exterior member 6 closes the opening 12 of the storage space 11. In a portion where the second exterior member 6 closes the opening 12, the thickness direction of the plate-shaped second exterior member 6 matches or substantially matches the thickness direction of the secondary battery 1.

The plate-shaped second exterior member 6 has an outer edge (member outer edge) 61. In the present embodiment, the outer edge 61 of the second exterior member 6 forms the outer edge of the secondary battery 1 together with the outer edge 51 of the flange 13. The outer edge 61 is continuous over the entire circumference in the circumferential direction of the opening 12. The outer edge 61 has a pair of first member

outer edges

62A and 62B along the vertical direction and a pair of second member

outer edges

63A and 63B along the horizontal direction. The first member outer edge 62A forms an outer edge of the second exterior member 6 at a portion protruding from the first opening edge 16A and the side wall 8A to the outer peripheral side, and the first member outer edge 62B is formed by the first opening edge. An outer edge of the second exterior member 6 is formed at a portion protruding from the edge 16B and the side wall 8B to the outer peripheral side. The second member outer edge 63A forms an outer edge of the second exterior member 6 at a portion protruding from the second opening edge 17A and the side wall 9A to the outer peripheral side, and the second member outer edge 63B is formed by the second opening edge. An outer edge of the second exterior member 6 is formed at a portion protruding outward from the edge 17B and the side wall 9B.

The outer edge 61 of the second exterior member 6 has four relay outer edges (member relay outer edges) 65A to 65D. The relay outer edge 65A extends continuously from the first member outer edge 62A to the second member outer edge 63A, and the relay outer edge 65B extends continuously from the first member outer edge 62A to the second member outer edge 63B. Is done. The relay outer edge 65C extends continuously from the first member outer edge 62B to the second member outer edge 63A, and the relay outer edge 65D continuously extends from the first member outer edge 62B to the second member outer edge 63B. It is extended. That is, each of the relay outer edges 65A to 65D extends continuously from a corresponding one of the pair of first member

outer edges

62A, 62B to a corresponding one of the pair of second member

outer edges

63A, 63B. Further, each of the relay outer edges 65A to 65D forms an obtuse angle at an intersection position with a corresponding one of the pair of first member

outer edges

62A and 62B. Each of the relay outer edges 65A to 65D forms an obtuse angle at the intersection with the corresponding one of the pair of second member

outer edges

63A and 63B.

では In the first exterior member 5, the distance from the bottom wall 7 to the opening 12 is much smaller than the distance between the

side walls

8A and 8B and the distance between the

side walls

9A and 9B. In the secondary battery 1, the dimension in the thickness direction is much smaller than each of the dimension in the vertical direction and the dimension in the horizontal direction. In the present embodiment, the distance between the side walls (first side walls) 8A and 8B is larger than the distance between the side walls (second side walls) 9A and 9B. Is smaller than the dimension in the lateral direction. Here, the distance between the

side walls

8A and 8B, that is, the distance between the first opening edges 16A and 16B corresponds to the dimension of the storage space 11 (opening 12) in the lateral direction of the secondary battery 1. The distance between the

side walls

9A and 9B, that is, the distance between the second opening edges 17A and 17B corresponds to the dimension of the storage space 11 (opening 12) in the vertical direction of the secondary battery 1. The distance from the bottom wall 7 to the opening 12 corresponds to the size of the storage space 11 in the thickness direction of the secondary battery 1. In one embodiment, the size of the storage space 11 in the thickness direction of the secondary battery 1 is a certain size of 8 mm or more and 25 mm or less. Further, in one embodiment, the size of the storage space 11 in the vertical direction of the secondary battery 1 is 266 mm, the size of the storage space 11 in the horizontal direction of the secondary battery 1 is 183 mm, and the thickness direction of the secondary battery 1 is Of the storage space 11 becomes 15 mm.

In one embodiment, the distance between the side walls (first side walls) 8A and 8B is smaller than the distance between the side walls (second side walls) 9A and 9B. May be larger than the dimension in the lateral direction. In another embodiment, the distance between the side walls (first side walls) 8A and 8B is the same or substantially the same as the distance between the side walls (second side walls) 9A and 9B. The dimension in the vertical direction may be the same or substantially the same as the dimension in the horizontal direction. However, in each case, the distance from the bottom wall 7 to the opening 12 is much smaller than the distance between the

side walls

8A and 8B and the distance between the

side walls

9A and 9B. In the secondary battery 1, the dimension in the thickness direction is much smaller than each of the dimension in the vertical direction and the dimension in the horizontal direction.

In one embodiment, the first exterior member 5 has a thickness of 0.02 mm or more on each of the bottom wall 7, the

side walls

8A, 8B, 9A, 9B, and the flange 13 except for a thin portion 93 of an opening valve 91 described later. The thickness is 0.3 mm or less. The substantially plate-shaped second exterior member 6 has a thickness of 0.02 mm or more and 0.3 mm or less.

FIG. 6 is a diagram illustrating the configuration of the electrode group 10. As shown in FIG. 6, the electrode group 10 is formed in, for example, a flat shape, and includes a positive electrode 21, a negative electrode 22, and

separators

23 and 25. The positive electrode 21 includes a positive electrode current collector foil 21A as a positive electrode current collector, and a positive electrode active material-containing layer 21B supported on the surface of the positive electrode current collector foil 21A. The positive electrode current collector foil 21A is an aluminum foil, an aluminum alloy foil, or the like, and has a thickness of about 10 μm to 20 μm. A slurry containing a positive electrode active material, a binder, and a conductive agent is applied to the positive electrode current collector foil 21A. Examples of the positive electrode active material include, but are not limited to, oxides, sulfides, and polymers capable of inserting and extracting lithium ions. In addition, from the viewpoint of obtaining a high positive electrode potential, it is preferable to use a lithium manganese composite oxide, a lithium nickel composite oxide, a lithium cobalt composite oxide, lithium iron phosphate, or the like as the positive electrode active material.

The negative electrode 22 includes a negative electrode current collector foil 22A as a negative electrode current collector, and a negative electrode active material-containing layer 22B supported on the surface of the negative electrode current collector foil 22A. The negative electrode current collector foil 22A is an aluminum foil, an aluminum alloy foil, a copper foil, or the like, and has a thickness of about 10 μm to 20 μm. A slurry containing a negative electrode active material, a binder, and a conductive agent is applied to the negative electrode current collector foil 22A. Examples of the negative electrode active material include, but are not particularly limited to, metal oxides, metal sulfides, metal nitrides, and carbon materials capable of inserting and extracting lithium ions. As the negative electrode active material, a material having a lithium ion storage / release potential of 0.4 V or higher with respect to the metal lithium potential, that is, a lithium ion storage / release potential of 0.4 V (vs. Li ⁺ / Li) or higher. Preferably, it is a substance. By using the negative electrode active material having such a lithium ion occlusion / release potential, an alloy reaction between aluminum or an aluminum alloy and lithium can be suppressed, so that the negative electrode current collector foil 22A and the components related to the negative electrode 22 include aluminum and aluminum. Aluminum alloy can be used. Examples of the negative electrode active material having a lithium ion occlusion / release potential of 0.4 V (vs. Li ⁺ / Li) or more include lithium-titanium composite oxides such as titanium oxide and lithium titanate, tungsten oxide, and amorphous tin. Oxides, niobium-titanium composite oxides, tin silicon oxides, silicon oxides, and the like are listed, and it is particularly preferable to use lithium titanium composite oxides as the negative electrode active material. When a carbon material that absorbs and releases lithium ions is used as the negative electrode active material, a copper foil may be used for the negative electrode current collector foil 22A. The carbon material used as the negative electrode active material has a lithium ion occlusion / release potential of about 0 V (vs. Li ⁺ / Li).

アルミニウム The aluminum alloy used for the positive electrode current collector foil 21A and the negative electrode current collector foil 22A desirably contains one or more elements selected from Mg, Ti, Zn, Mn, Fe, Cu and Si. The purity of aluminum and aluminum alloy can be 98% by weight or more, and preferably 99.99% by weight or more. Further, pure aluminum having a purity of 100% can be used as a material of the positive electrode current collector and / or the negative electrode current collector. The content of transition metals such as nickel and chromium in aluminum and aluminum alloys is preferably 100 ppm by weight or less (including 0 ppm by weight).

では In the positive electrode current collector foil 21A, a positive electrode current collector tab 21D is formed by one long side edge 21C and a portion in the vicinity thereof. In the present embodiment, the positive electrode current collecting tab 21D is formed over the entire length of the long side edge 21C. In the positive electrode current collecting tab 21D, the positive electrode active material containing layer 21B is not supported on the surface of the positive electrode current collecting foil 21A. In the negative electrode current collector foil 22A, the negative electrode current collector tab 22D is formed by the one long side edge 22C and the vicinity thereof. In the present embodiment, the negative electrode current collecting tab 22D is formed over the entire length of the long side edge 22C. In the negative electrode current collector tab 22D, the negative electrode active material containing layer 22B is not supported on the surface of the negative electrode current collector foil 22A.

(4) Each of the

separators

23 and 25 is formed of an electrically insulating material, and electrically insulates between the positive electrode 21 and the negative electrode 22. Each of the

separators

23 and 25 may be a separate sheet or the like from the positive electrode 21 and the negative electrode 22, or may be formed integrally with one of the positive electrode 21 and the negative electrode 22. Further, the

separators

23 and 25 may be formed from an organic material, an inorganic material, or a mixture of an organic material and an inorganic material. Examples of the organic material for forming the

separators

23 and 25 include engineering plastics and super engineering plastics. Examples of engineering plastics include polyamide, polyacetal, polybutylene terephthalate, polyethylene terephthalate, syndiotactic polystyrene, polycarbonate, polyamide imide, polyvinyl alcohol, polyvinylidene fluoride, and modified polyphenylene ether. Examples of the super engineering plastic include polyphenylene sulfide, polyether ether ketone, liquid crystal polymer, polyvinylidene fluoride, polytetrafluoroethylene (PTFE), polyether nitrile, polysulfone, polyacrylate, polyetherimide, and thermoplastic polyimide. Can be Examples of the inorganic material forming the

separators

23 and 25 include oxides (for example, aluminum oxide, silicon dioxide, magnesium oxide, phosphorus oxide, calcium oxide, iron oxide, and titanium oxide), and nitrides (for example, boron nitride, Aluminum nitride, silicon nitride, barium nitride) and the like.

In the electrode group 10, the positive electrode 21, the negative electrode 22, and the

separators

23, 25 are geometrically placed in a state in which the

separators

23, 25 are sandwiched between the positive electrode active material containing layer 21 B and the negative electrode active material containing layer 22 B, respectively ( It is wound in a flat shape around the winding axis B (imaginary). At this time, for example, the positive electrode 21, the separator 23, the negative electrode 22, and the separator 25 are wound in a state of being stacked in this order. In the electrode group 10, the positive electrode current collector tab 21 D of the positive electrode current collector foil 21 A protrudes from the negative electrode 22 and the

separators

23 and 25 to one side in the direction along the winding axis B. Then, the negative electrode current collector tab 22D of the negative electrode current collector foil 22A projects from the positive electrode 21 and the

separators

23 and 25 in the direction along the winding axis B on the opposite side to the side where the positive electrode current collector tab 21D protrudes. I do. The electrode group 10 is arranged such that the winding axis B extends along the lateral direction of the secondary battery 1, and the winding axis B is arranged along the side walls (second side walls) 9A and 9B. In the storage space 11, the positive electrode current collection tab 21 D is disposed at one end in the lateral direction of the secondary battery 1. Then, in the storage space 11, the negative electrode current collecting tab 22 D is disposed at the end of the secondary battery 1 on the side opposite to the side where the positive electrode current collecting tab 21 D is located.

In one embodiment, in the storage space 11, the electrode group 10 is impregnated with an electrolytic solution (not shown). As the electrolyte, a non-aqueous electrolyte is used. For example, a non-aqueous electrolyte prepared by dissolving an electrolyte in an organic solvent is used. In this case, as the electrolyte to be dissolved in the organic solvent, lithium perchlorate (LiClO ₄ ), lithium hexafluorophosphate (LiPF ₆ ), lithium tetrafluoroborate (LiBF ₄ ), and lithium arsenide hexafluoride (LiAsF ₆₎ ), lithium trifluoromethanesulfonate (LiCF ₃ SO ₃₎ and bistrifluoromethylsulfonylimide lithium _{_{[LiN (CF 3 SO 2)}} 2] lithium salts such as, and, mixtures thereof. As the organic solvent, cyclic carbonates such as propylene carbonate (PC), ethylene carbonate (EC) and vinylene carbonate; linear carbonates such as diethyl carbonate (DEC), dimethyl carbonate (DMC) and methyl ethyl carbonate (MEC); tetrahydrofuran (THF), cyclic ethers such as 2-methyltetrahydrofuran (2MeTHF) and dioxolane (DOX); linear ethers such as dimethoxyethane (DME) and diethoxyethane (DEE); γ-butyrolactone (GBL), acetonitrile (AN) And sulfolane (SL). These organic solvents are used alone or as a mixed solvent.

In one embodiment, as the non-aqueous electrolyte, a gel non-aqueous electrolyte in which a non-aqueous electrolyte and a polymer material are combined is used instead of the electrolyte. In this case, the above-mentioned electrolyte and organic solvent are used. Examples of the polymer material include polyvinylidene fluoride (PVdF), polyacrylonitrile (PAN), and polyethylene oxide (PEO).

In one embodiment, a solid electrolyte such as a polymer solid electrolyte and an inorganic solid electrolyte is provided as a non-aqueous electrolyte instead of the electrolytic solution. In this case, the

separators

23 and 25 need not be provided in the electrode group 10. Then, in the electrode group 10, a solid electrolyte is sandwiched between the positive electrode 21 and the negative electrode 22 instead of the

separators

23 and 25. Therefore, in the present embodiment, the positive electrode 21 and the negative electrode 22 are electrically insulated by the solid electrolyte.

As shown in FIGS. 1 and 2, in the first exterior member 5, an inclined surface 26A is provided on the outer surface of the side wall 8A, and an inclined surface 26B is provided on the outer surface of the side wall 8B. Each of the

inclined surfaces

26A and 26B is inclined with respect to the bottom wall 7 and with respect to the thickness direction of the secondary battery 1. Then, each of the

inclined surfaces

26A and 26B is inclined such that the direction toward the bottom wall 7 in the thickness direction of the secondary battery 1 is inward in the lateral direction of the secondary battery 1. In the present embodiment, the inclined surface 26A is provided at an end of the side wall 8A on the side where the bottom wall 7 is located in the thickness direction of the secondary battery 1, and a boundary line between the side wall 8A and the bottom wall 7 is formed. Form a part. The inclined surface 26B is provided at an end of the side wall 8B on the side where the bottom wall 7 is located in the thickness direction of the secondary battery 1, and forms a part of a boundary line between the side wall 8B and the bottom wall 7. Form. In the present embodiment, the inclined surface 26A is arranged at the center of the side wall 8A in the vertical direction, and the inclined surface 26B is arranged at the center of the side wall 8B in the vertical direction.

一対 A pair of

terminals

27A and 27B are attached to the outer surface of the first exterior member 5. One of the

terminals

27A and 27B serves as a positive terminal of the secondary battery 1, and the other of the

terminals

27A and 27B serves as a negative terminal of the secondary battery 1. In this embodiment, the terminal 27A is attached to the inclined surface 26A of the side wall 8A, and the terminal 27B is attached to the inclined surface 26B of the side wall 8B. Each of the

terminals

27A and 27B is formed of a conductive material, for example, any of aluminum, copper, stainless steel, and the like.

FIG. 7 shows an electrical connection configuration between the electrode group 10 and one of the pair of

terminals

27A and 27B. As shown in FIG. 7, the positive electrode current collecting tabs 21D of the electrode group 10 are bundled by welding such as ultrasonic welding. The bundle of the positive electrode current collecting tabs 21D is connected to one of the

terminals

27A and 27B (positive terminal) via one or more positive electrodes including the positive electrode backup lead 31A, the positive electrode relay lead 32A, and the positive terminal lead 33A. Is electrically connected to At this time, the connection between the positive electrode current collecting tab 21D and the positive electrode lead, the connection between the positive electrode leads, and the connection between the positive electrode lead and the positive electrode terminal are performed by welding such as ultrasonic welding. Here, the positive electrode lead is formed from a conductive metal. Further, the positive electrode terminal (corresponding to 27A, 27B), the positive electrode current collecting tab 21D, and the positive electrode lead are electrically insulated from the exterior part 3 (exterior members 5, 6) by an insulating member (not shown) or the like. Is done.

Similarly, the negative electrode current collecting tabs 22D of the electrode group 10 are bundled by welding such as ultrasonic welding. The bundle of the negative electrode current collection tabs 22D is connected to one of the

terminals

27A and 27B (negative terminal) via one or more negative electrodes including the negative electrode backup lead 31B, the negative electrode relay lead 32B, and the negative terminal lead 33B. Is electrically connected to At this time, the connection between the negative electrode current collection tab 22D and the negative electrode lead, the connection between the negative electrode leads, and the connection between the negative electrode lead and the negative electrode terminal are performed by welding such as ultrasonic welding. Here, the negative electrode lead is formed from a conductive metal. Further, the negative electrode terminal (corresponding to 27A and 27B), the negative electrode current collecting tab 22D, and the negative electrode lead are electrically insulated from the exterior part 3 (exterior members 5, 6) by an insulating member (not shown) or the like. Is done.

FIG. 8 shows the configuration of one of a pair of

side walls

9A and 9B along the lateral direction and the portion of the side wall (corresponding one of 9A and 9B) protruding to the outer peripheral side in the secondary battery 1 in the lateral direction. Shown in a vertical or substantially vertical section. As shown in FIG. 3 to FIG. 5, FIG. 7 and FIG. 8, the secondary battery 1 is formed with a welding portion 71 for hermetically welding the flange 13 and the second exterior member 6. The welding portion 71 is provided on the outer peripheral side with respect to the opening edge 15 of the opening 12, that is, on the side away from the opening 12 in a direction parallel to the opening surface of the opening 12. Therefore, the welding portion 71 is provided at a portion of the flange 13 and the second exterior member 6 that protrudes from the opening edge 15 to the outer peripheral side. The welded portion 71 extends along the opening edge 15 and is formed continuously over the entire circumference in the circumferential direction of the opening 12. Therefore, the flange 13 and the second exterior member 6 are hermetically welded over the entire circumference in the circumferential direction of the opening 12. As described above, the flange 13 and the second exterior member 6 are hermetically welded at the welding portion 71, so that the storage space 11 is sealed and the storage space 11 is sealed.

The welded portion 71 is formed between the outer edge 51 of the flange 13 and the opening edge 15, that is, between the outer edge 61 of the second exterior member 6 and the opening edge 15. In one embodiment, the outer edge of the weld 71 forms the outer edge 51 of the flange 13 and the outer edge 61 of the second exterior member 6. In another embodiment, each of the flange 13 and the second armor member 6 has a certain dimension from the outer edge of the welded portion 71 to the outer edge (51, 61). In one embodiment, the width of the weld 71, ie, the dimension between the inner and outer ends of the weld 71, is on the order of 2 mm. The dimension from the outer end of the welded portion 71 to the outer edge 51 of the flange 13 and the outer edge 61 of the second exterior member 6 is about 8.5 mm. In the welding portion 71, the flange 13 and the second exterior member 6 are welded by, for example, resistance seam welding. By performing the resistance seam welding, the cost is suppressed and the airtightness between the flange 13 and the second exterior member 6 is high as compared with the laser welding or the like.

Weld part 71 has a pair of

first weld parts

72A and 72B along the longitudinal direction, and a pair of

second weld parts

73A and 73B along the lateral direction. The first welded portion 72A is formed on the flange 13 and the second exterior member 6 at a portion protruding from the first opening edge 16A to the outer peripheral side. Then, the first welded portion 72A is formed between the first flange outer edge 52A and the first opening edge 16A, that is, between the first member outer edge 62A and the first opening edge 16A. . Further, the first welded portion 72B is formed on the flange 13 and the second exterior member 6 at a portion protruding from the first opening edge 16B to the outer peripheral side. Then, the first welded portion 72B is formed between the first flange outer edge 52B and the first opening edge 16B, that is, between the first member outer edge 62B and the first opening edge 16B. . The second welded portion 73A is formed on the flange 13 and the second exterior member 6 at a portion protruding from the second opening edge 17A to the outer peripheral side. The second welded portion 73A is formed between the second flange outer edge 53A and the second opening edge 17A, that is, between the second member outer edge 63A and the second opening edge 17A. . The second welded portion 73B is formed on the flange 13 and the second exterior member 6 at a portion protruding from the second opening edge 17B to the outer peripheral side. And the 2nd welding part 73B is formed between the 2nd flange outer edge 53B and the 2nd opening edge 17B, ie, between the 2nd member outer edge 63B and the 2nd opening edge 17B. .

溶接 Furthermore, the welding portion 71 has relay welding portions 75A to 75D (see FIGS. 10 to 12 described later). The relay weld 75A extends continuously from the first weld 72A to the second weld 73A, and the relay weld 75B continuously extends from the first weld 72A to the second weld 73B. It is extended. The relay weld 75C extends continuously from the first weld 72B to the second weld 73A, and the relay weld 75D continuously extends from the first weld 72B to the second weld 73B. It is extended. That is, each of the relay welds 75A to 75D extends continuously from a corresponding one of the pair of

first welds

72A, 72B to a corresponding one of the pair of

second welds

73A, 73B.

The relay welding portion 75A is formed between the relay outer edge 55A of the flange 13 and the opening edge 15, that is, between the relay outer edge 65A of the second exterior member 6 and the opening edge 15. Further, the relay welding portion 75B is formed between the relay outer edge 55B of the flange 13 and the opening edge 15, that is, between the relay outer edge 65B of the second exterior member 6 and the opening edge 15. The relay welding portion 75C is formed between the relay outer edge 55C of the flange 13 and the opening edge 15, that is, between the relay outer edge 65C of the second exterior member 6 and the opening edge 15. Then, the relay welded portion 75D is formed between the relay outer edge 55D of the flange 13 and the opening edge 15, that is, between the relay outer edge 65D of the second exterior member 6 and the opening edge 15. Each of the relay welds 75A to 75D is along a corresponding one of the relay outer edges 55A to 55D of the flange 13, that is, along a corresponding one of the relay outer edges 65A to 65D of the second exterior member 6, It is extended.

As shown in FIGS. 1, 2, and 8, an open valve 91 is provided on one of the pair of

side walls

9A and 9B. In the present embodiment, the open valve 91 is provided on the side wall 9B. When the internal pressure inside the exterior part 3, that is, the internal pressure of the storage space 11 becomes a predetermined value or more, the release valve 91 is opened. When the opening valve 91 is opened, the gas is discharged from the storage space 11 inside the exterior part 3 to the outside of the exterior part 3 via the opening valve 91. FIG. 4 shows a state in which the secondary battery 1 is viewed from the side where the release valve 91 (side wall 9B) is located with respect to the storage space 11 in the vertical direction. FIG. 8 shows a cross section passing through the opening valve 91.

FIG. 9 shows the configuration of the opening valve 91 and its vicinity on the inner surface of the side wall 9B. As shown in FIGS. 8 and 9, in the present embodiment, a groove 92 that is recessed toward the outer periphery is provided on the inner surface of the side wall 9B. In the opening valve 91, a thin portion 93 having a smaller thickness than the other portions of the

side walls

8A, 8B, 9A, 9B is formed by the groove 92. In the present embodiment, the opening valve 91 and the groove 92 are provided at the center of the side wall 9B in the lateral direction of the secondary battery 1. The groove 92 extends linearly or substantially linearly along the lateral direction of the secondary battery 1. The groove 92 is formed in a V-shape or a substantially V-shape in a cross section perpendicular or substantially perpendicular to the lateral direction on the side wall 9B. That is, in a cross section perpendicular or substantially perpendicular to the extending direction of the groove 92, the groove 92 is formed in a V shape or a substantially V shape. Then, in the thin portion 93 of the opening valve 91, the thickness of the side wall 9B becomes the thinnest at the V-shaped apex of the groove 92. Since the thin portion 93 is formed as described above, the opening valve 91 has a lower resistance to impact than the other portions of the

side walls

8A, 8B, 9A, 9B.

In one embodiment, in the opening valve 91, the extension dimension L1 of the groove 92 is about 50 mm. Then, the width W1 of the groove 92 is about 0.1 mm. In the present embodiment, the extension dimension L1 of the groove 92 corresponds to the dimension of the groove 92 in the lateral direction of the secondary battery 1, and the width W1 of the groove 92 corresponds to the groove 92 in the thickness direction of the secondary battery 1. Corresponds to the dimensions of Further, in one embodiment, the thickness t1 of the side wall 9B is about 0.1 mm at a portion other than the opening valve 91, and the thickness t2 of the side wall 9B at the V-shaped apex of the groove 92, that is, in the thin portion 93, The minimum thickness is about 0.01 mm or more and 0.02 mm or less.

In addition, the secondary battery 1 is formed with a bent portion 81 in which the flange 13 and the second exterior member 6 are bent together. The bent portion 81 is provided at a portion of the flange 13 and the second exterior member 6 that protrudes from the opening edge 15 toward the outer periphery. Therefore, the bent portion 81 is provided between the opening edge 15 and the outer edge 51 of the flange 13, that is, between the opening edge 15 and the outer edge 61 of the second exterior member 6. The bent portion 81 extends along the opening edge 15. In addition, the bent portion 81 may extend over a part of the circumferential direction of the opening 12, or may be continuous over the entire circumference of the opening 12. In the present embodiment, the bent portion 81 has a range in which the pair of first opening edges 16A, 16B extends and a pair of second opening edges 17A, 17B extending in the circumferential direction of the opening 12. Formed over both of the areas to be formed. Therefore, a bent portion 81 is formed in at least a range where the opening valve 91 is located in the circumferential direction of the opening 12. In the present embodiment, the bent portion 81 is provided between the opening edge 15 and the welded portion 71. Therefore, in the present embodiment, the welding portion 71 is provided between the bent portion 81 and the outer edge 51 of the flange 13, that is, between the bent portion 81 and the outer edge 61 of the second exterior member 6.

Each of the flange 13 and the second exterior member 6 extends from the opening edge 15 toward the bent portion 81 toward the outer peripheral side. That is, each of the flange 13 and the second exterior member 6 extends from the opening edge 15 to the bent portion 81 on a side away from the opening 12 in a direction parallel to the opening plane. Between the opening edge 15 and the bent portion 81, each of the flange 13 and the second exterior member 6 is parallel or substantially parallel to the opening plane. Then, between the opening edge 15 and the bent portion 81, the flange 13 and the second exterior member 6 are parallel or substantially parallel to each other.

延 The extending direction of each of the flange 13 and the second exterior member 6 is changed by the bent portion 81. In the present embodiment, the flange 13 and the second exterior member 6 are bent together at the bent portion 81 toward the side where the bottom wall 7 is located in the thickness direction of the secondary battery 1. Therefore, each of the flange 13 and the second exterior member 6 extends from the bent portion 81 to the outer edge (51; 61) toward the side where the bottom wall 7 of the first exterior member 5 is located. You. Between the bent portion 81 and the outer edge (51; 61), each of the flange 13 and the second exterior member 6 does not bend at a portion other than the bent portion 81, that is, other than the bent portion 81. The extension is performed without changing the extension direction at the site. Then, between the bent portion 81 and the outer edge (51, 61), the flange 13 and the second exterior member 6 are parallel or substantially parallel to each other.

Each of the flange 13 and the second exterior member 6 is bent at the bending portion 81 at any bending angle in the range of 30 ° or more and 150 ° or less. In one embodiment, each of the flange 13 and the second exterior member 6 is bent at the bending portion 81 at a bending angle of 80 °. When the bending angle falls within the above range, each of the flange 13 and the second exterior member 6 extends in a direction intersecting the opening surface of the opening 12 from the bending portion 81 to the outer edge (51; 61). It is extended along. In this case, each of the flange 13 and the second exterior member 6 is inclined from the bent portion 81 to the outer edge (51; 61) with respect to the opening surface of the opening 12, or is perpendicular to the opening surface. It extends along the direction. When the bending angle at the bent portion 81 is any angle greater than 90 ° and equal to or less than 150 °, each of the flange 13 and the second exterior member 6 is separated from the bent portion 81 by an outer edge ( 51; 61) so as to extend toward the inner peripheral side. That is, each of the flange 13 and the second exterior member 6 extends from the bent portion 81 to the outer edge (51; 61) toward the side approaching the opening 12 in a direction parallel to the opening surface. In this case, the bent portion 81 forms an outer peripheral end of a protruding portion from the opening edge 15 in each of the flange 13 and the second exterior member 6.

寸法 It is preferable that the dimension (distance) from the opening edge 15 (

side walls

8A, 8B, 9A, 9B) to the bent portion 81 is as small as possible. By reducing the size from the opening edge 15 to the bent portion 81, the vertical size of the secondary battery 1 and the horizontal size of the secondary battery 1 are prevented from increasing, and the energy of the secondary battery 1 is reduced. A decrease in density is prevented. The distance from the bent portion 81 to the outer edge 51 of the flange 13, that is, the distance from the bent portion 81 to the outer edge 61 of the second exterior member 6 is smaller than the distance from the opening 12 to the bottom wall 7. Preferably, it is small. Thereby, the size of the secondary battery 1 in the thickness direction is prevented from increasing, and the energy density of the secondary battery 1 is prevented from lowering. In one embodiment, the dimension from the opening edge 15 to the bent portion 81 is about 0.5 mm. Then, the dimension of the storage space 11 in the thickness direction of the secondary battery 1 is about 15 mm, and the dimension from the bent portion 81 to the outer edge (51, 61) is about 12.5 mm. Then, the distance from the bent portion 81 to the inner end of the welded portion 71 is about 2 mm.

The bent portion 81 has a pair of first

bent portions

82A and 82B along the vertical direction and a pair of second

bent portions

83A and 83B along the horizontal direction. The first bent portion 82A is formed on the flange 13 and the second exterior member 6 at a portion protruding from the first opening edge 16A to the outer peripheral side. The first bent portion 82A is formed between the first opening edge 16A and the first welded portion 72A. Further, the first bent portion 82B is formed in the flange 13 and the second exterior member 6 at a portion protruding from the first opening edge 16B to the outer peripheral side. And the 1st bending part 82B is formed between the 1st opening edge 16B and the 1st welding part 72B. The second bent portion 83A is formed on the flange 13 and the second exterior member 6 at a portion protruding from the second opening edge 17A to the outer peripheral side. The second bent portion 83A is formed between the second opening edge 17A and the second welded portion 73A. Further, the second bent portion 83B is formed in the flange 13 and the second exterior member 6 at a portion protruding from the second opening edge 17B to the outer peripheral side. And the 2nd bent part 83B is formed between the 2nd opening edge 17B and the 2nd welding part 73B.

Each of the relay outer edges 65A to 65D intersects with a corresponding one of the pair of first

bent portions

82A and 82B. At the intersection position, the angle formed by each of the relay outer edges 65A to 65D and the corresponding one of the first

bent portions

82A and 82B is an acute angle. Further, each of the relay outer edges 65A to 65D intersects with a corresponding one of the pair of second

bent portions

83A and 83B. At the intersection position, the angle formed by each of the relay outer edges 65A to 65D and the corresponding one of the second

bent portions

83A and 83B is an acute angle.

Similarly, each of the relay welds 75A to 75D intersects a corresponding one of the pair of first

bent portions

82A and 82B. At the intersection position, the angle formed by each of the relay welds 75A to 75D and the corresponding one of the first

bent portions

82A and 82B is an acute angle. Further, each of the relay welded portions 75A to 75D intersects with a corresponding one of the pair of second

bent portions

83A and 83B. At the intersection, the angle formed by each of the relay welds 75A to 75D and the corresponding one of the second

bent portions

83A and 83B is an acute angle.

In the present embodiment, since the bent portion 81 is provided as described above, the extending portion from the bent portion 81 to the outer edge 51 of the flange 13, and the outer edge 61 of the second exterior member 6 from the bent portion 81. The extended portion up to is located on the outer peripheral side with respect to the

side walls

8A, 8B, 9A, 9B. Further, at the protruding portion from the second opening edge 17B and the side wall 9B to the outer peripheral side, an extended portion from the second bent portion 83B to the second flange outer edge 53B of the flange 13 and the second bent portion. An extended portion from the portion 83B to the second member outer edge 63B of the second exterior member 6 is located on the outer peripheral side with respect to the side wall 9B and the release valve 91.

In one embodiment, the outer edges (51; 61) of the flange 13 and the second exterior member 6 are connected to the bottom wall by the opening valve 91 in a range where the side wall 9B extends in the circumferential direction of the opening 12. 7 is located on the side where it is located. In this case, in the range where the opening valve 91 is located in the circumferential direction of the opening 12, the extending portion from the second bent portion 83B to the second flange outer edge 53B of the flange 13 and the second bent portion 83B A portion extending from the second outer member 6 to the second member outer edge 63B of the second exterior member 6 is opposed to the opening valve 91 from the outer peripheral side. In this case, in the range where the opening valve 91 is located in the circumferential direction of the opening 12, the extending portion from the second bent portion 83 B to the second flange outer edge 53 B of the flange 13 and the second bent portion. It is preferable that an extended portion from the portion 83B to the second member outer edge 63B of the second exterior member 6 is separated from the release valve 91 to the outer peripheral side to some extent. Thereby, when gas is discharged from the opening valve 91, a path for the discharged gas is secured.

Further, in another embodiment, the outer edges (51; 61) of the flange 13 and the second exterior member 6 are in contact with the opening valve 91 in a range where the side wall 9B extends in the circumferential direction of the opening 12. Therefore, it is located on the side opposite to the side where the bottom wall 7 is located. However, in this case, from the viewpoint of preventing physical contact with the open valve 91, the outer wall (51; 61) of each of the flange 13 and the second exterior member 6 has a bottom wall positioned with respect to the open valve 91. Not far away from the side to do. Therefore, in the thickness direction of the secondary battery 1, the distance between the outer edge (51; 61) of each of the flange 13 and the second exterior member 6 from the opening valve 91 is very small.

Next, a method for manufacturing the secondary battery 1 of the present embodiment will be described. In manufacturing the secondary battery 1, the first exterior member 5 and the second exterior member 6 are formed. At this time, an opening valve 91 is formed on the side wall 9B of the first exterior member 5. In this embodiment, the opening valve 91 is formed by using a cylindrical roller having a projection formed on the outer peripheral surface. In forming the opening valve 91, the inner surface of the side wall 9B is pressed by the protrusion of the roller. At this time, the inner surface of the side wall 9B is pressurized at the center of the side wall 9B in the lateral direction of the secondary battery 1. Then, the roller is rotated in a state where the inner surface of the side wall 9B is pressed by the protrusion of the roller. As a result, a V-shaped groove 92 is formed on the inner surface of the side wall 9B so as to be recessed toward the outer periphery. The groove 92 forms a thin portion 93 having a smaller thickness than other portions of the

side walls

8A, 8B, 9A, 9B. Thus, an open valve 91 including the thin portion 93 is formed on the side wall 9B.

When the

exterior members

5 and 6 are formed, the second exterior member 6 is arranged to face the flange 13 of the first exterior member 5. Then, as shown in FIG. 10, the flange 13 and the second exterior member 6 are hermetically welded to form a welded portion 71. In forming the welded portion 71, first, a pair of first welded

portions

72A and 72B and a pair of second welded

portions

73A and 73B are formed. Then, the relay welding portions 75A to 75D are formed in a state of being inclined with respect to the

first welding portions

72A and 72B and the

second welding portions

73A and 73B. Here, the

first welds

72A, 72B and the

second welds

73A, 73B form four intersections α1 to α4. Each of the relay welds 75A to 75D is formed between the opening edge 15 and a corresponding one of the intersections α1 to α4. Therefore, each of the relay welds 75A to 75D is formed on the inner peripheral side (closer to the opening edge 15) with respect to the corresponding one of the intersections α1 to α4.

Then, as shown in FIG. 11, the flange 13 and the second exterior member 6 are cut at a position on the outer peripheral side with respect to the welded portion 71, and the outer peripheral side is trimmed (removed) from the cut position. Thereby, the outer edge 51 of the flange 13 and the outer edge 61 of the second exterior member 6 are formed. At this time, in each of the relay welds 75A to 75D, at the outer end of the relay weld (the corresponding one of the 75A to 75D) or at a position close to the outer end, the corresponding one of the relay welds (75A to 75D) ), The flange 13 and the second exterior member 6 are cut. Therefore, the intersections α1 to α4 formed by the

first welds

72A and 72B and the

second welds

73A and 73B are removed by trimming. By trimming to remove the intersection points α1 to α4, the relay outer edges 55A to 55D of the flange 13 and the relay outer edges 65A to 65D of the second exterior member 6 are formed.

Then, as shown in FIG. 12, the flange 13 and the second exterior member 6 are bent together at the bending line H1 on the inner peripheral side (the side closer to the opening 12) with respect to the first welded portion 72A. , A first bent portion 82A is formed. Similarly, the first bent portion 82B is formed by bending the flange 13 and the second exterior member 6 together on the inner peripheral side with respect to the first welded portion 72B. The second bent portion is formed by bending the flange 13 and the second exterior member 6 together at the bending line H2 on the inner peripheral side (closer to the opening 12) with respect to the second welded portion 73A. 83A are formed. Similarly, by bending the flange 13 and the second exterior member 6 together on the inner peripheral side with respect to the second welded portion 73B, a second bent portion 83B is formed.

Since the relay outer edges 55A to 55D and 65A to 65D are formed as described above, the second portion of the extension from the first bent portion 82A to the first flange outer edge 52A and the first member outer edge 62A is formed. Interference with the extending portion from each of the

bent portions

83A and 83B to the corresponding second flange outer edge (53A; 53B) and the corresponding second member outer edge (63A; 63B) is effectively prevented. Similarly, the second flange outer edge corresponding to each of the second

bent portions

83A and 83B of the extended portion from the first bent portion 82B to the first flange outer edge 52B and the first member outer edge 62B. (53A; 53B) and the interference with the extended portion to the corresponding second member outer edge (63A; 63B) are effectively prevented. Thereby, in the circumferential direction of the opening 12, the bent portion extends over both the range where the first opening edges 16A and 16B extend and the range where the second opening edges 17A and 17B extend. 81 are easily formed.

Next, the operation and the like when the secondary battery 1 is used will be described. In the secondary battery 1, for example, when used for a long time, gas may be generated in the storage space 11 in which the electrode group 10 is stored. When gas is generated in the storage space 11, the internal pressure of the exterior part 3 increases. When the internal pressure of the exterior part 3 becomes equal to or more than a predetermined value, a crack occurs in the thin part 93 of the first exterior member 5 which is thinner than other parts. Thereby, the release valve 91 is opened, and the gas is discharged from the storage space 11 inside the exterior part 3 to the outside of the exterior part 3 via the release valve 91. Here, the predetermined value which is the threshold value of the internal pressure at which the opening valve 91 is opened is set lower than the internal pressure when the secondary battery 1 is in an excessively expanded state. Therefore, the release valve 91 functions as a safety mechanism for the secondary battery 1.

Here, as described above, the thin portion 93 of the open valve 91 is thinner than other portions of the first exterior member 5. For this reason, the thin portion 93 of the opening valve 91 has low resistance to an external impact. In the present embodiment, a bent portion 81 is provided at a portion of the flange 13 and the second exterior member 6 that protrudes from the opening edge 15 toward the outer periphery. The extending portion from the bent portion 81 to the outer edge 51 of the flange 13 and the extending portion from the bent portion 81 to the outer edge 61 of the second exterior member 6 are provided on the

side walls

8A, 8B, 9A, 9B. On the other hand, it is located on the outer peripheral side. Therefore, the extending portion from the second bent portion 83B to the second flange outer edge 53B of the flange 13, and the second bent portion 83B to the second member outer edge 63B of the second exterior member 6 Is located on the outer peripheral side with respect to the release valve 91.

Because of the above-described configuration, in the present embodiment, when the secondary battery 1 is used or the like, the extended portion from the second bent portion 83B to the second flange outer edge 53B and the second member outer edge 63B. Thereby, external physical contact with the opening valve 91 is effectively prevented. Further, even if the secondary battery 1 receives an external impact or the like, the parts other than the open valve 91 physically contact, so that the stress or the like acting on the open valve 91 is reduced. Therefore, by preventing external physical contact with the open valve 91, the open valve 91 is appropriately protected against external impact and the like. This reduces the possibility that the opening valve 91 will be damaged, for example, when the secondary battery 1 receives an external impact.

In addition, in the present embodiment, a bent portion 81 is provided between the opening edge 15 and the welding portion 71 at a portion of the flange 13 and the second exterior member 6 protruding from the opening edge 15. Then, at the bent portion 81, the flange 13 and the second exterior member 6 are bent together. With such a configuration, when the exterior part 3 expands outward due to an increase in the internal pressure of the exterior part 3, the stress due to the expansion is limited to a range A1 between the bent part 81 and the welded part 71 (see FIG. 8). ). Therefore, concentration of stress on the inner end of the welded portion 71 is prevented. Since the stress is dispersed in the range A1, even if the expansion of the exterior part 3 increases to some extent, the stress acting on the welded portion 71 and the like does not increase. For this reason, even if the internal pressure of the exterior part 3 becomes high and the exterior part 3 expands to some extent, the occurrence of cracks and the like at portions other than the open valve 91 of the exterior part 3 is effectively prevented. Thereby, even if the exterior part 3 expands to some extent, the airtightness of the storage space 11 in which the electrode group 10 is arranged to the outside of the exterior part 3 is appropriately maintained, and the performance and the like of the secondary battery 1 are appropriately secured. .

In addition, in the present embodiment, the flange 13 and the second exterior member 6 are bent together at the bent portion 81 to the side where the bottom wall 7 is located. For this reason, by reducing the distance from the bent portion 81 to the

outer edges

51 and 61 compared to the distance from the opening 12 to the bottom wall 7, the size of the secondary battery 1 in the thickness direction is prevented from increasing. Is done. Thereby, a decrease in the energy density of the secondary battery 1 is prevented.

(Modifications and application examples)
In the first modification shown in FIGS. 13 to 15, only a pair of

bent portions

83A and 83B along the horizontal direction are formed as the bent portions 81, and the bent portions (82A and 82B) along the vertical direction are formed. ) Is not formed. That is, only the bent portions corresponding to the second

bent portions

83A and 83B of the first embodiment are formed. Here, FIG. 13 shows the secondary battery 1 as viewed from the side where the bottom wall 7 is located in the thickness direction (the arrow Z1 side). 14 shows the secondary battery 1 viewed from one side in the vertical direction (arrow X2 side), and FIG. 15 shows the secondary battery 1 from one side in the horizontal direction (arrow Y1 side). It is shown in a state where it is seen.

Also in this modification, in each of the protruding portions from the second opening edges 17A and 17B, the flange 13 and the second exterior member 6 extend from the opening edge 15 to the bent portion 81 (the

bent portion

83A or 83B). It extends toward the outer peripheral side. In each of the protruding portions from the second opening edges 17A and 17B, the extending direction of each of the flange 13 and the second exterior member 6 is changed by the bent portion 81 (the

bent portion

83A or 83B). I do. For example, the flange 13 and the second exterior member 6 are bent at the

bent portions

83A and 83B, respectively, toward the side where the bottom wall 7 is located in the thickness direction of the secondary battery 1.

Further, in the present modified example, in each of the protruding portions from the first opening edges 16A and 16B, the flange 13 and the second exterior member 6 respectively have the opening 12 from the opening edge 15 to the outer edge (51; 61). Is extended toward the outer peripheral side. That is, the flange 13 and the second exterior member 6 extend from the first opening edges 16A, 16B to the outer edges (51, 61) in the direction parallel to the opening surface without changing the extending direction. It is extended toward the side away from.

Also in this modified example, a bent portion 81 (

bent portions

83A and 83B) is provided between the opening edge 15 and the outer edges (51, 61), and in the bent portion 81, the flange 13 and the second exterior member are provided. 6 bends together. The bent portion 81 is formed in a range where the

side walls

9A and 9B extend in the circumferential direction of the opening 12. For this reason, also in this modification, the bent portion 81 is formed in at least the range where the opening valve 91 is located in the circumferential direction of the opening 12 as in the above-described embodiment and the like. Therefore, also in this modified example, similarly to the above-described embodiments and the like, external physical contact with the open valve 91 is prevented, and the open valve 91 is appropriately protected against external impact and the like.

Note that the bent portion 81 only needs to be provided in the circumferential direction of the opening 12 at least over a range where the opening valve 91 is located. For example, in a configuration in which the opening valve 91 is provided on the side wall 9B, the bent portion 81 may be provided in at least the range in which the side wall 9B extends in the circumferential direction of the opening 12. Thereby, in the range where the opening valve 91 is located in the circumferential direction of the opening 12, the extending portion from the bent portion 81 to the outer edge (51, 61) of the flange 13 and the second exterior member 6 is formed by the side wall 9B. And on the outer peripheral side with respect to the release valve 91.

In the second modified example shown in FIGS. 16 to 18, similarly to the above-described first embodiment and the like, a pair of first

bent portions

82A and 82B along the vertical direction as the bent portion 81, and A pair of

bent portions

83A and 83B are provided along the lateral direction. An opening valve 91 is formed on the side wall 9B, and the opening valve 91 is located at the center of the side wall 9B in the lateral direction of the secondary battery 1. Here, FIG. 17 shows the secondary battery 1 as viewed from one side (arrow X2 side) in the vertical direction. FIG. 18 shows the configuration of one of a pair of

side walls

9A and 9B along the horizontal direction and the configuration of a protruding portion from the side walls (corresponding one of 9A and 9B) to the outer peripheral side in the secondary battery 1. A cross section perpendicular or substantially perpendicular to the direction is shown, and a cross section passing through the opening valve 91 is shown.

In the present modification, an outer edge concave portion 95 is formed on the outer edge 51 of the flange 13 and the outer edge 61 of the second exterior member 6. In the outer edge concave portion 95, the second flange outer edge 53B and the second member outer edge 63B are recessed in the thickness direction on the side opposite to the side where the bottom wall 7 is located. Further, the outer edge concave portion 95 is formed over a range where the opening valve 91 is located in the circumferential direction of the opening 12. Therefore, the outer edge concave portion 95 is formed over a part of the range in which the side wall 9 B extends in the circumferential direction of the opening 12.

By forming the outer edge concave portion 95, the outer edges (51; 61) of the flange 13 and the second exterior member 6 are opposed to the open valve 91 in a range where the open valve 91 is located in the circumferential direction of the opening 12. Therefore, it is located on the side opposite to the side where the bottom wall 7 is located. For this reason, in the range where the opening valve 91 is located in the circumferential direction of the opening 12, the extended portion from the second bent portion 83B to the second flange outer edge 53B and the second bent portion 83B from the second bent portion Does not oppose the release valve 91 from the outer peripheral side. However, even within the range in which the side wall 9B extends in the circumferential direction of the opening 12, the second flange outer edge 53B and the second member outer edge 63B are located at positions other than the outer edge recess 95 with respect to the opening valve 91. Is located on the side where the bottom wall 7 is located. Therefore, even within the range in which the side wall 9B extends in the circumferential direction of the opening 12, the second flange outer edge 53B and the second member outer edge 63B in most of the portions deviating from the open valve 91 in the horizontal direction. Is located on the side where the bottom wall 7 is located with respect to the opening valve 91.

In the present modification, as described above, in the range where the opening valve 91 is located in the circumferential direction of the opening 12, the outer edges (51; 61) of the flange 13 and the second exterior member 6 are opposed to the opening valve 91. Therefore, it is located on the side opposite to the side where the bottom wall 7 is located. Thereby, the obstruction of the path of the gas discharged from the opening valve 91 by the extending portion from the bent portion 81 to the outer edge (51; 61) of the flange 13 and the second exterior member 6 is more likely to occur. Effectively prevented. Therefore, when the gas is discharged from the opening valve 91, the path of the discharged gas is more appropriately secured.

Further, in the present modification, even within the range in which the side wall 9B extends in the circumferential direction of the opening 12, the second flange outer edge 53B and the second member outer edge 63B are formed at portions other than the outer edge recess 95. The opening valve 91 is located on the side where the bottom wall 7 is located. For this reason, even when the outer edge concave portion 95 is formed, similarly to the above-described embodiments and the like, external physical contact with the open valve 91 is prevented, and the open valve 91 is appropriately protected against external impact and the like. Protected.

In the above-described embodiments and the like, the groove 92 of the release valve 91 is provided on the inner surface of the side wall 9B, but the groove 92 may be provided on the outer surface of the side wall 9B. In the above-described embodiments and the like, the groove 92 of the release valve 91 extends linearly or substantially linearly along the lateral direction of the secondary battery 1, but the extending direction and the extending state of the groove are different. However, the present invention is not limited to this. For example, in a third modification shown in FIGS. 19 and 20, a groove 92 that is recessed inward is provided on the outer surface of the side wall 9B. The grooves 92 form two pairs of sides of a rectangle, and a diagonal line of the rectangle. Here, FIG. 19 shows a configuration of one of a pair of

side walls

9A and 9B along the lateral direction and a portion protruding from the side walls (corresponding one of 9A and 9B) to the outer peripheral side in the secondary battery 1. A cross section perpendicular or substantially perpendicular to the lateral direction is shown, and a cross section passing through the opening valve 91 is shown. FIG. 20 shows the configuration of the opening valve 91 and its vicinity on the outer surface of the side wall 9B.

では In the present modification, the two pairs of rectangular sides formed by the grooves 92 have a pair of long sides and a pair of short sides. The pair of long sides extend along the lateral direction of the secondary battery 1, and the pair of short sides extend along the thickness direction of the secondary battery 1. Also in this modified example, in the open valve 91, a thin portion 93 having a smaller thickness than the other portions of the

side walls

8A, 8B, 9A, 9B is formed by the groove 92. In this modification, the release valve 91 and the groove 92 are provided at the center of the side wall 9B in the lateral direction of the secondary battery 1. Also in the present modification, the groove 92 is formed in a V-shape or a substantially V-shape in a cross section perpendicular or substantially perpendicular to the extending direction of the groove 92. Then, in the thin portion 93 of the opening valve 91, the thickness of the side wall 9B becomes the thinnest at the V-shaped apex of the groove 92. Since the thin portion 93 is formed as described above, also in this modified example, the release valve 91 has a lower resistance to impact than the other portions of the

side walls

8A, 8B, 9A, 9B.

The groove 92 is formed by stamping the outer surface of the side wall 9B with a punch or the like. Further, in one embodiment, the thickness t1 of the side wall 9B is about 0.1 mm at a portion other than the opening valve 91, and the thickness t2 of the side wall 9B at the V-shaped apex of the groove 92, that is, in the thin portion 93, The minimum thickness is about 0.01 mm or more and 0.02 mm or less.

In the fourth modification shown in FIG. 21, in the side wall 8A, the inclined surface 26A is vertically continuous from the side wall 9A to the side wall 9B, and the inclined surface 26A extends in the vertical direction over the entire length of the side wall 8A. Is done. Then, in the side wall 8B, the inclined surface 26B is vertically continuous from the side wall 9A to the side wall 9B, and the inclined surface 26B extends in the vertical direction over the entire length of the side wall 8B. Also in this modification, the terminal 27A is attached to the inclined surface 26A of the side wall 8A, and the terminal 27B is attached to the inclined surface 26B of the side wall 8B. However, in this modified example, the dimensions of the

terminals

27A and 27B in the longitudinal direction of the secondary battery 1 are larger than those of the above-described first embodiment and the like.

でも Also in this modified example, an open valve 91 is formed on the side wall 9B, as in the above-described embodiment and the like. Then, in the present modified example, as in the first modified example and the like, only the pair of

bent portions

83A and 83B along the lateral direction is formed as the bent portion 81. For this reason, in this modification, the bent portion 81 is formed in a range where the

side walls

In a modification, a pair of first bent portions 82A extending in the vertical direction are formed in the configuration in which the

inclined surfaces

26A and 26B are formed as in the fourth modification, similarly to the first embodiment. , 82B and a pair of second

bent portions

83A, 83B along the lateral direction may be formed as bent portions 81.

FIG. 22 shows a part of a battery pack including a plurality of secondary batteries 1 of a fourth modification as an application example of the above-described secondary battery 1. In the battery pack of this application example, the assembled battery 100 is formed from the two

secondary batteries

1A and 1B. The

secondary batteries

1A and 1B used in the battery pack 100 have the same configuration as the secondary battery 1 of the fourth modified example (see FIG. 21).

In the assembled battery 100, the

secondary batteries

1A and 1B are stacked in the stacking direction (the direction indicated by the arrows Z3 and Z4). The stacking direction of the

secondary batteries

1A, 1B is the direction in which the

secondary batteries

1A, 1B are arranged. Here, in the battery pack 100, a first intersecting direction (direction indicated by arrows X3 and X4) intersecting with the stacking direction, and a second intersecting direction with respect to both the stacking direction and the first intersecting direction. (Directions indicated by arrows Y3 and Y4) are defined. In this embodiment, the first cross direction is perpendicular or substantially perpendicular to the stacking direction, and the second cross direction is perpendicular or substantially perpendicular to both the stack direction and the first cross direction. .

(4) The

secondary batteries

1A and 1B are arranged adjacent to each other in the stacking direction. Further, in the assembled battery 100 of this application example, each of the

secondary batteries

1A and 1B is stacked with the thickness direction being parallel or substantially parallel to the stacking direction. Each of the

secondary batteries

1A and 1B is arranged such that the vertical direction is parallel or substantially parallel to the first cross direction, and the horizontal direction is parallel or substantially parallel to the second cross direction. You. In the battery pack 100, the

secondary batteries

1A and 1B are arranged with the second exterior member 6 of the secondary battery 1A facing the bottom wall 7 of the secondary battery 1B. Further, in the battery pack 100, the

secondary batteries

1A and 1B are arranged in the first intersecting direction without being shifted from each other or almost not shifted. Then, the

secondary batteries

1A and 1B are arranged in the second intersecting direction without being displaced from each other or almost not displaced.

It is preferable that an electrically insulating insulating plate (not shown) is provided between the

secondary batteries

1A and 1B. In this case, the second exterior member 6 of the secondary battery 1A faces the bottom wall 7 of the secondary battery 1B with the insulating plate interposed therebetween. For this reason, contact between the exterior parts 3 of the

secondary batteries

1A and 1B is prevented by the insulating plate. As described above, since the

secondary batteries

1A and 1B are stacked, in each of the

secondary batteries

1A and 1B of the assembled battery 100, the side walls (first side walls) 8A and 8B extend along the first cross direction. And the side walls (second side walls) 9A and 9B extend along the second intersecting direction.

In this application example, the

secondary batteries

1A and 1B are electrically connected by the bus bar 101 which is a connecting member. The bus bar 101 is formed of, for example, a conductive metal. By the bus bar 101, the

secondary batteries

1A and 1B are electrically connected in series or in parallel. In the assembled battery 100, one of the

terminals

27A and 27B of the secondary battery 1A (the first target terminal) is connected to the corresponding one of the

terminals

27A and 27B of the secondary battery 1B (the second terminal). (A target terminal) via the bus bar 101. In the application example of FIG. 22, the bus bar 101 is connected to the terminal 27B of the secondary battery 1A and to the terminal 27B of the secondary battery 1B. The target terminal (27A or 27B) of the secondary battery 1A and the target terminal (27A or 27B) of the secondary battery 1B connected by the bus bar 101 are the same with respect to the center position of the battery pack 100 in the second cross direction. Located on the side of. That is, the target terminal (27A or 27B) of the secondary battery 1A and the target terminal (27A or 27B) of the secondary battery 1B are the same with respect to the storage space 11 of the

secondary batteries

1A and 1B in the second cross direction. Located on the side of.

In this application example, in each of the

secondary batteries

1A and 1B, the opening valve 91 is provided on the side wall 9B. Therefore, the path of the gas discharged from the respective open valves 91 of the

secondary batteries

1A and 1B is not obstructed by the bus bar 101. Therefore, when gas is discharged from the respective open valves 91 of the

secondary batteries

1A and 1B, the path of the discharged gas is more appropriately secured.

In the assembled battery 100 of the application example of FIG. 22, the secondary battery 1 of the fourth modification is used, but the present invention is not limited to this. For example, any one of the secondary batteries 1 of the above-described embodiments and the like such as the secondary battery 1 of the first embodiment may be stacked in the same manner as the application example of FIG. Also in this case, an assembled battery and a battery pack are formed from the stacked secondary batteries 1.

In the fifth modification shown in FIG. 23, an open valve 91 is provided on one of a pair of

side walls

8A and 8B along the longitudinal direction, and the open valve 91 is formed on the side wall 8A. In the present modification, similarly to the first embodiment and the like, the bent portion 81 has a range in which the pair of first opening edges 16A and 16B extend in the circumferential direction of the opening 12 and a pair of first opening edges 16A and 16B. The second opening edges 17A and 17B are formed over both of the extended ranges. Therefore, a bent portion 81 is formed in at least a range where the opening valve 91 is located in the circumferential direction of the opening 12. Therefore, also in this modified example, similarly to the above-described embodiments and the like, external physical contact with the open valve 91 is prevented, and the open valve 91 is appropriately protected against external impact and the like.

In this modification, the electrode group 10 is arranged in the storage space 11 with the winding axis B extending along the lateral direction of the secondary battery 1. In such a configuration, in the storage space 11, the generated gas easily accumulates at both ends in the lateral direction of the secondary battery 1. That is, in the storage space 11, the generated gas is likely to accumulate in the area where the positive electrode current collecting tab 21D is arranged and the area where the negative electrode current collecting tab 22D is arranged. In this modification, since the open valve 91 is formed on the side wall 8A, it is easy to discharge gas from the storage space 11 to the outside of the exterior unit 3 via the open valve 91.

As described above, the bent portion 81 only needs to be provided in the circumferential direction of the opening 12 at least over a range where the opening valve 91 is located. For example, in a configuration in which the opening valve 91 is provided on the side wall 8A, the bent portion 81 may be provided in at least the range in which the side wall 8A extends in the circumferential direction of the opening 12. Thereby, in the range where the opening valve 91 is located in the circumferential direction of the opening 12, the extending portion from the bent portion 81 to the outer edge (51; 61) of the flange 13 and the second exterior member 6 is formed by the side wall 8A. And on the outer peripheral side with respect to the release valve 91.

In the above-described embodiments and the like, the welded portion 71 is formed between the bent portion 81 and the outer edge (51; 61) of the flange 13 and the second exterior member 6, but is not limited thereto. is not. In a modification, a bent portion 81 is formed between the welded portion 71 and the outer edge (51; 61) of the flange 13 and the second exterior member 6. In this case, a welded portion 71 is formed between the opening edge 15 and the bent portion 81, and the welded portion 71 is located on the inner peripheral side with respect to the bent portion 81.

In a modification, a plurality of electrode groups may be stored in the storage space 11. In another modification, the second exterior member 6 is formed in a bottomed cylindrical shape similar to the first exterior member 5 instead of a plate shape. In this case, the second exterior member 6 is also formed to have a bottom wall, a side wall, and a flange. Then, the flange 13 of the first exterior member 5 and the flange of the second exterior member 6 are hermetically welded at the welding portion 71. Also in the secondary battery 1 of the present modification, the flange 13 and the second exterior member 6 are hermetically welded by the welded portion 71 over the entire circumference in the circumferential direction of the opening 12. The storage space 11 in which the electrode group 10 is stored is sealed from the outside of the exterior unit 3.

According to the secondary battery of at least one of these embodiments or examples, the flange and the second exterior member are bent together at the bent portion provided at the protruding portion from the opening edge to the outer peripheral side. The bent portion is provided at least in a circumferential direction of the opening over a range する where the opening valve is located. Due to the bent portion, the extending portion from the bent portion to each outer edge of the flange and the second exterior member is located on the outer peripheral side with respect to the release valve. For this reason, it is possible to provide a secondary battery in which the opening valve provided in the exterior part is appropriately protected, and a battery pack including the secondary battery.

Although some embodiments of the present invention have been described, these embodiments have been presented by way of example only, and are not intended to limit the scope of the inventions. These new embodiments can be implemented in other various forms, and various omissions, replacements, and changes can be made without departing from the spirit of the invention. These embodiments and their modifications are included in the scope and gist of the invention, and are also included in the invention described in the claims and their equivalents.

Claims

A first exterior member having a bottom wall and a side wall and formed of metal, wherein a storage space is defined by the bottom wall and the side wall, and the storage space has an opening on a side opposite to the bottom wall. A first exterior member including a flange projecting outward from an opening edge of the opening with respect to the side wall;
An electrode group including a positive electrode and a negative electrode, which is housed in the housing space,
A second exterior member formed of metal and arranged to face the flange, wherein the second exterior member closes the opening of the storage space;
A welding portion that seals the storage space by welding the flange and the second exterior member over the entire circumference of the opening at a portion protruding from the opening edge to the outer peripheral side;
An opening valve that is provided on the side wall of the first exterior member and that is opened when an internal pressure of the storage space becomes a predetermined value or more;
The flange and the second exterior member are bent together at the protruding portion from the opening edge to the outer peripheral side, and a bend is provided over at least a range where the opening valve is located in the circumferential direction of the opening. A bent portion that extends from the bent portion to the outer edge of each of the flange and the second exterior member with respect to the opening valve,
A secondary battery comprising:
Each of the flange and the second exterior member is extended from the opening edge to the bent portion toward the outer peripheral side,
The extending direction of each of the flange and the second exterior member changes at the bent portion,
The secondary battery according to claim 1.
The secondary battery according to claim 2, wherein each of the flange and the second exterior member extends from the bent portion to the outer edge along a direction intersecting an opening surface of the opening.
The secondary of claim 3, wherein each of the flange and the second exterior member extends from the bent portion to the outer edge toward a side where the bottom wall of the first exterior member is located. 5. battery.
The secondary battery according to any one of claims 1 to 4, wherein the bent portion extends along the opening edge.
In the range where the opening valve is located in the circumferential direction of the opening, the outer edges of the flange and the second exterior member are recessed on the side opposite to the side where the bottom wall is located,
In the range where the opening valve is located in the circumferential direction of the opening, the outer edges of the flange and the second exterior member are opposite to the opening valve on the side where the bottom wall is located. Located on the side,
The secondary battery according to claim 1.
The secondary battery according to any one of claims 1 to 6, wherein the open valve includes a thin portion in which the thickness of the side wall is thinner than other portions.
The secondary battery according to claim 7, wherein in the thin portion, the inner surface of the side wall is recessed toward the outer periphery, or the outer surface of the side wall is recessed toward the inner periphery.
The side wall of the first exterior member,
A pair of first side walls facing each other and each extending along the longitudinal direction;
A pair of second side walls facing each other and each extending along a horizontal direction crossing the vertical direction;
With
The secondary battery further includes a pair of terminals each attached to one corresponding outer surface of the pair of first side walls in the first exterior member.
The secondary battery according to claim 1.
The release valve is provided on at least one of the pair of second side walls,
A connection member that electrically connects the secondary battery to another secondary battery is connected to at least one of the pair of terminals,
The secondary battery according to claim 9.
The release valve is provided on at least one of the pair of first side walls,
In the electrode group, the positive electrode and the negative electrode are wound around a winding axis,
The electrode group is arranged in the storage space in a state where the winding axis is along the pair of second side walls,
The positive electrode includes a positive electrode current collection tab protruding from the negative electrode to one side in a direction along the winding axis,
The negative electrode includes a negative electrode current collection tab that protrudes from the positive electrode to a side opposite to a side where the positive electrode current collection tab protrudes in a direction along the winding axis,
In the storage space, the positive electrode current collecting tab is disposed at one end in the lateral direction, and the negative electrode current collecting tab is opposite to the side where the positive electrode current collecting tab is located in the horizontal direction. Located at the end,
The secondary battery according to claim 9.
A plurality of the secondary batteries according to any one of claims 1 to 8, comprising:
The plurality of secondary batteries include a first secondary battery and a second secondary battery that are stacked adjacent to each other,
Each of the first secondary battery and the second secondary battery is stacked in a state where the thickness direction matches the stacking direction,
Battery pack.
In each of the first secondary battery and the second secondary battery, the side wall of the first exterior member is
A pair of first side walls which are opposed to each other and each extend along a first intersecting direction intersecting the laminating direction;
A pair of second side walls facing each other and each extending along a second intersecting direction intersecting both the laminating direction and the first intersecting direction;
With
Each of the first secondary battery and the second secondary battery further includes a pair of terminals respectively attached to one corresponding outer surface of the pair of first side walls in the first exterior member. Prepare,
The battery pack according to claim 12.
A connection member that electrically connects the first secondary battery and the second secondary battery,
The connection member is connected to a first target terminal that is one of the pair of terminals of the first secondary battery, and the connection member is connected to the first target terminal of the second secondary battery. 2 is connected to a second target terminal that is located on the same side as the first target terminal with respect to the storage space in the cross direction of 2,
In each of the first secondary battery and the second secondary battery, the release valve is provided on at least one of the pair of second side walls,
The battery pack according to claim 13.