JP6862577B2 - How to manufacture a secondary battery - Google Patents

Description

An embodiment of the present invention relates to a method for manufacturing a secondary battery.

Generally, a secondary battery includes an electrode group including a positive electrode and a negative electrode, and an exterior portion for accommodating the electrode group. In some secondary batteries, the exterior portion is formed of two exterior members, and each of the two exterior members is formed of stainless steel. In this secondary battery, the first exterior member, which is one of the exterior members, is formed in a tubular shape with a bottom having a bottom wall and a side wall, and the bottom wall and the side wall define a storage space for accommodating the electrode group. To. The storage space has an opening on the side opposite to the bottom wall. Further, in the first exterior portion, a flange is formed on a portion opposite to the bottom wall, and the flange defines the edge of the 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. Further, on the outside of the edge of the opening, a welded portion is formed in which the flange and the second exterior member are airtightly welded. The weld is formed over the entire circumference of the opening. The welded portion seals the storage space to the outside.

In the secondary battery as described above, gas is required to be discharged from the storage space at the time of manufacture from the viewpoint of preventing an increase in internal resistance and a decrease in life. At the time of manufacturing, it is required to airtightly weld the flange and the second exterior member in a state where the gas is discharged from the storage space to seal the storage space to the outside.

International Publication No. 2016/20147

An object to be solved by the present invention is to provide a method for manufacturing a secondary battery in which gas is appropriately discharged from a storage space to the outside during manufacturing.

According to the embodiment, the method for manufacturing a secondary battery includes forming an electrode group including a positive electrode and a negative electrode, and forming a first exterior member and a second exterior member from stainless steel. The first exterior member is formed so that the storage space is defined by the bottom wall and the side wall, and the storage space has an opening on the side opposite to the bottom wall. In the formation of the first exterior member, a flange is formed at a portion opposite to the bottom wall, and the flange is formed so that the edge of the opening of the storage space is defined by the flange. In the manufacturing method, the convex portion is formed on the flange in the formation of the flange, or is formed on the second exterior member in the formation of the second exterior member. Further, in the manufacturing method, in a state where the electrode group is arranged in the storage space, the second exterior member is arranged so as to face the flange to close the opening of the storage space. At this time, the convex portion formed on one of the flange and the second exterior member is arranged outside the edge of the opening, and the convex portion projects toward the other of the flange and the second exterior member. A second exterior member is arranged. In the manufacturing method, the flange and the second exterior member are airtightly welded over the entire circumference of the opening on the outside of the convex portion to form the welded portion. Then, in the manufacturing method, the gas in the storage space is discharged from the opening position between the welded portion and the convex portion and in the vicinity of the convex portion.

FIG. 1 is a perspective view schematically showing an example of a secondary battery manufactured by the manufacturing method according to the first embodiment. FIG. 2 is a perspective view schematically showing the secondary battery of FIG. 1 in a state where the first exterior member, the second exterior member, and the electrode group are disassembled from each other. FIG. 3 is a schematic view illustrating the configuration of the electrode group of the secondary battery of FIG. FIG. 4 is a schematic view showing an electrical connection configuration of an electrode group to a positive electrode terminal (negative electrode terminal) in the secondary battery of FIG. FIG. 5 is a schematic view showing the secondary battery of FIG. 1 as viewed from the side where the bottom wall of the first exterior member is located in the thickness direction. FIG. 6 is a schematic view showing a state in which the second exterior member is arranged so as to face the flange at the time of manufacturing the secondary battery by the manufacturing method according to the first embodiment. FIG. 7A is a schematic view showing the configuration of the convex portion and its vicinity in the first embodiment of the first embodiment in the state of FIG. 6 at the time of manufacture. FIG. 7B is a cross-sectional view schematically showing a cross section of V1-V1 of FIG. 7A. FIG. 7C is a cross-sectional view schematically showing a V2-V2 cross section of FIG. 7A. FIG. 8A is a schematic view showing the configuration of the convex portion and its vicinity in the second embodiment of the first embodiment in the state of FIG. 6 at the time of manufacture. FIG. 8B is a cross-sectional view schematically showing a cross section of V3-V3 of FIG. 8A. FIG. 9A is a schematic view showing the configuration of the convex portion and its vicinity in the third embodiment of the first embodiment in the state of FIG. 6 at the time of manufacture. FIG. 9B is a cross-sectional view schematically showing a cross section of V4-V4 of FIG. 9A. FIG. 9C is a cross-sectional view schematically showing a cross section of V5-V5 of FIG. 9A. FIG. 10 is a schematic view showing a state in which the flange and the second exterior member are airtightly welded in a part of the circumferential direction of the opening from the state of FIG. FIG. 11 is a schematic view showing a state in which the electrolytic solution is injected into the storage space from the state of FIG. 10 and the odor flange and the second exterior member are airtightly welded in a range not welded in the circumferential direction of the opening. is there. FIG. 12 is a schematic view showing a state in which gas is discharged to the outside of the exterior portion from the opening hole in the vicinity of one of the convex portions in the state of FIG. FIG. 13 is a schematic view showing a state in which a welded portion is formed between the opening hole from which gas is discharged and the convex portion from the state of FIG. FIG. 14 is a schematic view showing a state in which an opening hole different from the opening hole from which the gas was discharged in FIG. 12 is formed in the vicinity of the other side of the convex portion from the state of FIG. FIG. 15 is a schematic view showing a state in which gas is discharged from the opening hole formed in FIG. 14 from the state of FIG. 14 and a welded portion is formed between the opening hole and the convex portion. FIG. 16 is a schematic view showing a state in which a welded portion is formed between the edge of the opening and the convex portion from the state of FIG. FIG. 17 is a cross-sectional view schematically showing a convex portion and its vicinity in a state where the internal pressure inside the exterior portion is lower than the external pressure outside the exterior portion in the first embodiment. FIG. 18 is a cross-sectional view schematically showing a convex portion and its vicinity in a state where the internal pressure inside the exterior portion is lower than the external pressure outside the exterior portion in the second embodiment. FIG. 19 is a schematic view showing a system used for verification regarding a decompression state of a storage space at the time of manufacturing a secondary battery by the manufacturing method according to the first embodiment. FIG. 20 is a schematic view showing a measurement result of a change over time in the degree of decompression of the storage space of the subject in the verification using the system of FIG.

Hereinafter, embodiments will be described with reference to FIGS. 1 to 20.

(First Embodiment)
FIG. 1 shows an example of a secondary battery 1 manufactured by the manufacturing method according to the first embodiment. The secondary battery 1 is, for example, a non-aqueous electrolyte battery. As shown in FIG. 1, the secondary battery 1 includes an exterior portion 3. The exterior portion 3 is formed of a first exterior member 5 and a second exterior member 6. Each of the exterior members 5 and 6 is made of stainless steel. The first exterior member 5 is formed in a tubular shape with a bottom. In the present embodiment, the first exterior member 5 has a bottom wall 7 and four side walls 8A to 8D, and is formed in a substantially rectangular tubular 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 to 8D. The electrode group 10 is stored in the storage space 11.

FIG. 2 shows a state in which the first exterior member 5, the second exterior member 6, and the electrode group 10 are disassembled from each other. As shown in FIG. 2, the storage space 11 has an opening 12 on the side opposite to the bottom wall 7. Here, in the secondary battery 1, in the vertical direction (directions indicated by arrows X1 and X2), in the horizontal direction perpendicular to or substantially perpendicular to the vertical direction (directions indicated by arrows Y1 and Y2), and in the vertical direction. On the other hand, a thickness direction (direction indicated by arrow Z1 and arrow Z2) that is vertical or substantially vertical and is perpendicular or substantially perpendicular to the lateral direction is defined. In the secondary battery 1, the side walls 8A and 8B are arranged vertically apart from each other with the storage space 11 interposed therebetween, and the side walls 8C and 8D are arranged laterally apart from each other with the storage space 11 interposed therebetween. Will be done. Further, each of the side walls 8A to 8D extends from the bottom wall 7 toward the opening 12 along the thickness direction, and the storage space 11 faces one side (arrow Z2 side) in the thickness direction at the opening 12. To open.

In the first exterior member 5, a flange 13 is provided at a portion opposite to the bottom wall 7. The flange 13 projects outward with respect to the side walls 8A to 8D, that is, on the side away from the opening 12. Then, the flange 13 defines the edge 15 of the opening 12 over the entire circumference in the circumferential direction of the opening 12. In the present embodiment, the second exterior member 6 is formed in a plate shape, and is, for example, a substantially rectangular plate member. The second exterior member 6 is arranged so as to face the flange 13, and faces the flange 13 from the side where the opening 12 opens. In the present embodiment, the second exterior member 6 projects outward from the side walls 8A to 8D, that is, toward the side away from the opening 12, over the entire circumference of the opening 12 in the circumferential direction. Therefore, in the region outside the edge 15 of the opening 12, 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 is arranged in a state in which the thickness direction of the plate-shaped second exterior member 6 coincides with or substantially coincides with the thickness direction of the secondary battery 1. By arranging the second exterior member 6 as described above, the second exterior member 6 closes the opening 12 of the storage space 11.

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 8C and 8D, respectively. Therefore, in the secondary battery 1, the dimensions in the thickness direction are much smaller than the dimensions in the vertical direction and the dimensions in the horizontal direction. In the present embodiment, the distance between the side walls 8A and 8B is smaller than the distance between the side walls 8C and 8D, and in the secondary battery 1, the dimension in the vertical direction is larger than the dimension in the horizontal direction. And small. The first exterior member 5 has a wall thickness of 0.02 mm or more and 0.3 mm or less at each of the bottom wall 7, the side walls 8A to 8D, and the flange 13. The plate-shaped second exterior member 6 has a wall thickness of 0.02 mm or more and 0.3 mm or less.

FIG. 3 is a diagram illustrating the configuration of the electrode group 10. As shown in FIG. 3, the electrode group 10 is formed in a flat shape, for example, 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, polymers, and the like that can occlude and release lithium. Further, from the viewpoint of obtaining a high positive electrode potential, it is preferable to use lithium manganese composite oxide, lithium nickel composite oxide, lithium cobalt composite oxide, lithium iron phosphate and 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 12A. Examples of the negative electrode active material include, but are not limited to, metal oxides, metal sulfides, metal nitrides, carbon materials and the like that can occlude and release lithium ions. As the negative electrode active material, a substance having a lithium ion storage / release potential of 0.4 V or more with respect to a metallic lithium potential, that is, a lithium ion storage / discharge potential of 0.4 V (vs. ^{Li +} / Li) or more. It is preferably a substance. By using a negative electrode active material having such a lithium ion occlusion / release potential, the alloy reaction between aluminum or an aluminum alloy and lithium can be suppressed. Aluminum alloy can be used. Examples of the negative electrode active material having a storage / release potential of lithium ions of 0.4 V (vs. ^{Li +} / Li) or more include titanium oxide, lithium titanium composite oxide such as lithium titanate, tungsten oxide, and amorphous tin. Examples thereof include oxides, niobium-titanium composite oxides, tin silicon oxides, silicon oxide and the like, and it is particularly preferable to use lithium titanium composite oxides as the negative electrode active material. When a carbon material that occludes and releases lithium ions is used as the negative electrode active material, it is preferable to use a copper foil for the negative electrode current collecting foil 22A. The carbon material used as the negative electrode active material has an occlusion / release potential of lithium ions of ^{about 0 V (vs. Li +} / Li).

The aluminum alloy used for the positive electrode current collecting foil 21A and the negative electrode current collecting foil 22A preferably 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, preferably 99.99% by weight or more. Further, pure aluminum having a purity of 100% can be used as a material for 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).

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

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 sheet or the like separate from the positive electrode 21 and the negative electrode 22, or may be integrally formed with one of the positive electrode 21 and the negative electrode 22. Further, the separators 23 and 25 may be formed of an organic material, an inorganic material, or a mixture of the organic material and the inorganic material. Examples of the organic material 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, polyamideimide, polyvinyl alcohol, polyvinylidene fluoride, and modified polyphenylene ether. Examples of super engineering plastics include polyphenylene sulfide, polyetheretherketone, liquid crystal polymer, polyvinylidene fluoride, polytetrafluoroethylene (PTFE), polyethernitrile, polysulfone, polyacrylate, polyetherimide, and thermoplastic polyimide. Be done. Examples of the inorganic material forming the separators 23 and 25 include oxides (for example, aluminum oxide, silicon dioxide, magnesium oxide, phosphor oxide, calcium oxide, iron oxide, titanium oxide) and nitrides (for example, boron nitride, etc.). (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 and 25 are wound shaft B with the separators 23 and 25 sandwiched between the positive electrode active material-containing layer 21B and the negative electrode active material-containing layer 22B. It is wound into a flat shape around the center. 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. Further, in the electrode group 10, the positive electrode current collecting tab 21D of the positive electrode current collecting foil 21A projects to one side in the direction along the winding axis B with respect to the negative electrode 22 and the separators 23 and 25. Then, the negative electrode current collecting tab 22D of the negative electrode current collecting foil 22A protrudes from the positive electrode 21 and the separators 23 and 25 on the side opposite to the side on which the positive electrode current collecting tab 21D protrudes in the direction along the winding axis B. To do. The electrode group 10 is arranged so that the winding shaft B is parallel or substantially parallel to the lateral direction of the secondary battery 1.

In one embodiment, the electrode group 10 is impregnated with an electrolytic solution (not shown) in the storage space 11. As the electrolytic solution, a non-aqueous electrolytic solution is used. For example, a non-aqueous electrolytic solution 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 ), lithium hexafluoroarsenide (LiAsF ₆₎ ), _{Lithium salts such as lithium trifluoromethanesulfonate (LiCF 3} SO ₃ ) and bistrifluoromethylsulfonylimide lithium [LiN (CF ₃ SO ₂ ) ₂ ], and mixtures thereof. Further, as the organic solvent, cyclic carbonates such as propylene carbonate (PC), ethylene carbonate (EC) and vinylene carbonate; chain carbonates such as diethyl carbonate (DEC), dimethyl carbonate (DMC) and methyl ethyl carbonate (MEC); tetrahydrofuran. Cyclic ethers such as (THF), dimethyltetrahydrofuran (2MeTHF), and dioxolane (DOX); chain ethers such as dimethoxyethane (DME) and diethoxyethane (DEE); γ-butyrolactone (GBL), acetonitrile (AN). And sulfolane (SL) and the like. These organic solvents can be used alone or as a mixed solvent.

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

Further, in a certain embodiment, instead of the electrolytic solution, a solid electrolyte such as a polymer solid electrolyte and an inorganic solid electrolyte is provided as a non-aqueous electrolyte. In this case, the electrodes 23 and 25 may not be provided in the electrode group 10. Then, in the electrode group 10, instead of the separators 23 and 25, a solid electrolyte is sandwiched between the positive electrode 21 and the negative electrode 22. Therefore, in this embodiment, the solid electrolyte electrically insulates between the positive electrode 21 and the negative electrode 22.

As shown in FIGS. 1 and 2, an inclined surface 26 is provided between the bottom wall 7 and the side wall 8C on the outer surface of the first exterior member 5. Further, on the outer surface of the first exterior member 5, an inclined surface 27 is provided between the bottom wall 7 and the side wall 8D. In the first exterior member 5, the positive electrode terminal 31 is attached to the inclined surface 26, and the negative electrode terminal 32 is attached to the inclined surface 27. Each of the terminals 31 and 32 is formed from a conductive material, for example, from any of aluminum, copper, stainless steel, and the like.

FIG. 4 shows an electrical connection configuration of the electrode group 10 to the positive electrode terminal 31 (negative electrode terminal 32). As shown in FIG. 4, the positive electrode current collecting tab 21D of the electrode group 10 is bundled by welding such as ultrasonic welding, and the bundle of the positive electrode current collecting tab 21D is connected to the positive electrode backup lead 35 by welding such as ultrasonic welding. Will be done. Further, the positive electrode backup lead 35 is connected to the positive electrode lead 36 by welding such as ultrasonic welding, and the positive electrode lead 36 is connected to the positive electrode terminal lead 37 by welding such as ultrasonic welding. Then, the positive electrode terminal lead 37 is connected to the positive electrode terminal 31. Each of the positive electrode backup lead 35, the positive electrode lead 36, and the positive electrode terminal lead 37 is formed of a conductive material. Therefore, the positive electrode current collecting tab 21D is electrically connected to the positive electrode terminal 31 via the positive electrode backup lead 35, the positive electrode lead 36, and the positive electrode terminal lead 37. The positive electrode current collecting tab 21D, the positive electrode backup lead 35, the positive electrode lead 36, the positive electrode terminal lead 37, and the positive electrode terminal 31 are each electrically insulated from the exterior members 5 and 6.

Similarly, the negative electrode current collecting tab 22D of the electrode group 10 is bundled by welding such as ultrasonic welding, and the bundle of the negative electrode current collecting tab 22D is connected to the negative electrode backup lead 41 by welding such as ultrasonic welding. Further, the negative electrode backup lead 41 is connected to the negative electrode lead 42 by welding such as ultrasonic welding, and the negative electrode lead 42 is connected to the negative electrode terminal lead 43 by welding such as ultrasonic welding. Then, the negative electrode terminal lead 43 is connected to the negative electrode terminal 32. Each of the negative electrode backup lead 41, the negative electrode lead 42, and the negative electrode terminal lead 43 is formed of a conductive material. Therefore, the negative electrode current collecting tab 22D is electrically connected to the negative electrode terminal 32 via the negative electrode backup lead 41, the negative electrode lead 42, and the negative electrode terminal lead 43. The negative electrode current collecting tab 22D, the negative electrode backup lead 41, the negative electrode lead 42, the negative electrode terminal lead 43, and the negative electrode terminal 32 are each electrically insulated from the exterior members 5 and 6.

FIG. 5 shows the secondary battery 1 as viewed from the side where the bottom wall 7 of the first exterior member 5 is located in the thickness direction. As shown in FIG. 5, the secondary battery 1 is formed with welded portions 45 to 48 for airtightly welding the flange 13 and the second exterior member 6. Each of the welded portions 45 to 48 is provided on the outside of the edge 15 of the opening 12, that is, on the side away from the opening 12 with respect to the edge 15. In the present embodiment, the welded portion 45 is formed in the flange 13 and the second exterior member 6 at a portion protruding outward in the vertical direction from the side wall 8A, and extends along the lateral direction. The welded portion 46 is formed in the flange 13 and the second exterior member 6 at a portion protruding outward in the vertical direction from the side wall 8B, and extends along the lateral direction. Further, the welded portion 47 is formed in the flange 13 and the second exterior member 6 at a portion protruding outward in the lateral direction from the side wall 8C, and extends along the vertical direction. The welded portion 48 is formed in the flange 13 and the second exterior member 6 at a portion protruding outward in the lateral direction from the side wall 8D, and extends along the vertical direction. In the view of the secondary battery 1 such as FIG. 5 viewed from one side in the thickness direction, the welded portions 45 to 48 are indicated by broken lines.

One end of the welded portion 45 is continuous with the welded portion 47, and the other end is continuous with the welded portion 48. One end of the welded portion 46 is continuous with the welded portion 47, and the other end is continuous with the welded portion 48. Therefore, the flange 13 and the second exterior member 6 are airtightly welded by the welded portions 45 to 48 over the entire circumference in the circumferential direction of the opening 12. Therefore, the storage space 11 in which the electrode group 10 is housed is sealed to the outside of the exterior portion 3 by the welded portions 45 to 48. In the welded portions 45 to 48, the flange 13 and the second exterior member 6 are welded by, for example, resistance seam welding. By performing resistance seam welding, the cost can be suppressed as compared with laser welding and the like, and the airtightness between the flange 13 and the second exterior member 6 is high.

Next, a method of manufacturing the secondary battery 1 in the present embodiment will be described. In the manufacture of the secondary battery 1, the first exterior member 5 is formed from stainless steel. At this time, the first exterior member 5 is formed in a state where the storage space 11 is defined by the bottom wall 7 and the side walls 8A to 8D, and the storage space 11 has an opening 12 on the side opposite to the bottom wall 7. .. Further, the first exterior member 5 is formed to have a wall thickness of 0.02 mm or more and 0.3 mm or less. In the formation of the first exterior member 5, the flange 13 is formed on the portion of the first exterior member 5 opposite to the bottom wall 7. At this time, the flange 13 is in a state in which the flange 13 projects to the side away from the opening 12 with respect to the side walls 8A to 8D, and the flange 13 defines the edge 15 of the opening 12 over the entire circumference in the circumferential direction of the opening 12. Is formed.

In the manufacture of the secondary battery 1, the second exterior member 6 is formed from stainless steel. In one embodiment, the second exterior member 6 is formed in a plate shape. The second exterior member 6 is formed to have a wall thickness of 0.02 mm or more and 0.3 mm or less. Further, in the production of the secondary battery 1, an electrode group 10 including a positive electrode 21 and a negative electrode 22 is formed. In a certain embodiment, the electrode group 10 is formed by winding the positive electrode 21, the negative electrode 22, and the separators 23 and 25 as described above. When the exterior members 5 and 6 and the electrode group 10 are formed, the electrode group 10 is arranged in the storage space 11. In one embodiment, the electrode group 10 in which the positive electrode 21, the negative electrode 22, and the separators 23 and 25 are wound is arranged so that the winding axis B is parallel or substantially parallel to the lateral direction of the secondary battery 1 in the storage space 11. Place it in a state where it becomes.

Then, the positive electrode current collecting tab 21D of the electrode group 10 is electrically connected to the positive electrode terminal 31 via the positive electrode backup lead 35, the positive electrode lead 36, and the positive electrode terminal lead 37. Similarly, the negative electrode current collecting tab 22D of the electrode group 10 is electrically connected to the negative electrode terminal 32 via the negative electrode backup lead 41, the negative electrode lead 42, and the negative electrode terminal lead 43. Further, an insulating member that electrically insulates each of the positive electrode current collecting tab 21D, the positive electrode backup lead 35, the positive electrode lead 36, the positive electrode terminal lead 37, and the positive electrode terminal 31 from the exterior members 5 and 6 is installed. Similarly, an insulating member that electrically insulates each of the negative electrode current collecting tab 22D, the negative electrode backup lead 41, the negative electrode lead 42, the negative electrode terminal lead 43, and the negative electrode terminal 32 with respect to the exterior members 5 and 6 is installed.

Then, with the electrode group 10 arranged in the storage space 11, the second exterior member 6 is arranged so as to face the flange 13. FIG. 6 shows a state in which the second exterior member 6 is arranged to face the flange 13 at the time of manufacturing the secondary battery 1. FIG. 6 shows a state viewed from the side where the bottom wall 7 of the first exterior member 5 is located. As shown in FIG. 6, by arranging the second exterior member 6 so as to face the flange 13, the second exterior member 6 is formed on the side walls 8A to 8D over the entire circumference of the opening 12 in the circumferential direction. On the other hand, it projects to the side away from the opening 12. Then, in the region outside the edge 15 of the opening 12, the arranged second exterior member 6 faces the flange 13 over the entire circumference of the opening 12 in the circumferential direction. Further, in the present embodiment, the second exterior member 6 is made to face the flange 13 so that the thickness direction of the plate-shaped second exterior member 6 coincides with or substantially coincides with the thickness direction of the secondary battery 1. .. By arranging the second exterior member 6 as described above, the opening 12 of the storage space 11 is closed by the second exterior member 6.

Further, in the manufacture of the secondary battery 1, an opening hole (first opening hole) 51A is formed in the flange 13 in the formation of the flange 13, or the second exterior member 6 is formed in the formation of the second exterior member 6. The opening hole 51A is formed. Therefore, at the time of manufacturing the secondary battery 1, an opening hole 51A is formed in one of the flange 13 and the second exterior member 6. At this time, the opening hole 51A is formed to have a diameter of φa. The diameter φa is, for example, about 1 mm. Further, in the manufacture of the secondary battery 1, the convex portions 52A and 52B are formed on the flange 13 in the formation of the flange 13, or the convex portions 52A and 52B are formed on the second exterior member 6 in the formation of the second exterior member 6. To form. Therefore, at the time of manufacturing the secondary battery 1, each of the convex portions 52A and 52B is formed on one of the flange 13 and the second exterior member 6. At this time, the convex portion (first convex portion) 52A is formed in the vicinity of the opening hole 51A. Further, the convex portions 52A and 52B are formed at positions separated from each other.

When the second exterior member 6 is arranged so as to face the flange 13, the opening holes 51A and the convex portions 52A and 52B are arranged outside the edge 15 of the opening 12. Further, in a state where the second exterior member 6 is arranged to face the flange 13, each of the convex portions 52A and 52B is the other of the flange 13 and the second exterior member 6, that is, the flange 13 and the second exterior. It protrudes toward one of the portions where the convex portions 52A and 52B are not provided. In the present embodiment, the second exterior member 6 is made to face the flange 13 in a state where the protruding directions of the convex portions 52A and 52B coincide with or substantially coincide with the thickness direction of the secondary battery 1. In one embodiment, for example, the flange 13 is provided with the convex portions 52A and 52B, and the convex portions 52A and 52B are respectively projected toward the second exterior member 6, and the second exterior member 6 is attached to the flange 13. Make them face each other.

Further, in a certain embodiment, by arranging the second exterior member 6 so as to face the flange 13, the flange 13 or the second exterior member 6 is opened at a portion protruding outward in the vertical direction from the side wall 8A. The holes 51A and the protrusions 52A and 52B are located. At this time, the convex portion (first convex portion) 52A is located at the end on the side closer to the side wall 8C in the lateral direction, and the convex portion (second convex portion) 52B is located on the side closer to the side wall 8D in the lateral direction. Located at the end of. Therefore, when the second exterior member 6 is arranged so as to face the flange 13, the convex portion 52B is located apart from the opening hole 51A and the convex portion 52A in the lateral direction of the secondary battery 1. In the view of the secondary battery 1 as viewed from one side in the thickness direction as shown in FIG. 6, the convex portions 52A and 52B are shown in black.

When the second exterior member 6 is arranged so as to face the flange 13, the opening hole (first opening hole) 51A is arranged at a distance D1a from the edge 15 of the opening 12. The distance D1a is, for example, about 20 mm. Further, in a state where the second exterior member 6 is arranged so as to face the flange 13, the opening hole 51A is arranged on the outside, that is, on the side far from the opening 12 with respect to the convex portion (first convex portion) 52A. Will be done. The convex portion 52A is arranged in the vicinity of the opening hole 51A. At this time, the distance D2a from the opening hole 51A to the convex portion 52A is 6 mm or less. When the second exterior member 6 is arranged so as to face the flange 13, the convex portion 52A is arranged at a distance D3a from the edge 15 of the opening 12, and the convex portion 52B is arranged at a distance D3a from the edge 15 of the opening 12. D3b are placed apart. In the present embodiment, the distances D3a and D3b are the same or substantially the same size with respect to each other, and each of the distances D3a and D3b is, for example, about 4 mm.

Here, the convex portions 52A and 52B will be described. 7A to 7C show a first embodiment of the configuration of the convex portion 52A (52B) and its vicinity. 7A to 7C show the convex portion 52A (52B) and its vicinity in the state of FIG. 6 at the time of manufacture. 7B shows a V1-V1 cross section of FIG. 7A, and FIG. 7C shows a V2-V2 cross section of FIG. 7A. In the state of FIG. 6, the internal pressure inside the exterior portion 3 is the same as or substantially the same as the external pressure outside the exterior portion 3. In this embodiment, each of the convex portions 52A and 52B is formed in a tunnel vault form. Therefore, in each of the convex portions 52A and 52B, the longitudinal direction (tunnel axis direction), the width direction perpendicular to or substantially perpendicular to the longitudinal direction, and the width direction perpendicular or substantially perpendicular to the longitudinal direction and perpendicular to the width direction. Alternatively, a substantially vertical protruding direction is specified. In this embodiment, the longitudinal directions of the convex portions 52A and 52B coincide with or substantially coincide with the vertical direction of the secondary battery 1, and the width directions of the convex portions 52A and 52B are set in the lateral direction of the secondary battery 1. Match or substantially match with. Here, in FIG. 7B, the convex portion 52A (52B) is shown in a cross section perpendicular to or substantially perpendicular to the longitudinal direction, and in FIG. 7C, the convex portion 52A (52B) is parallel to or substantially perpendicular to the longitudinal direction. It is shown in a cross section that is parallel and perpendicular to or substantially perpendicular to the width direction.

In each of the convex portions 52A and 52B, the cross-sectional shape perpendicular to or substantially vertical to the longitudinal direction is made uniform or substantially uniform over the entire length in the longitudinal direction. Further, in this embodiment, the cross-sectional shapes of the convex portions 52A and 52B that are perpendicular to or substantially vertical to the longitudinal direction are formed in a substantially U shape or a substantially semicircular arc shape. Each of the protrusions 52A and 52B is formed in a dimension (corresponding one of D4a and D4b) in the longitudinal direction. The dimensions D4a and D4b are the same or substantially the same size with respect to each other, and each of the dimensions D4a and D4b is, for example, about 10 mm. Further, each of the convex portions 52A and 52B is formed in a width (corresponding one of W1a and W1b) in the width direction. The widths W1a and W1b have the same or substantially the same size with respect to each other, and each of the widths W1a and W1b is, for example, about 1.2 mm. Then, each of the convex portions 52A and 52B is formed to the protruding end (the corresponding one of P1a and P1b). The protruding dimensions P1a and P1b are the same or substantially the same size with respect to each other, and each of the protruding dimensions P1a and P1b is, for example, about 0.4 mm.

Further, in the second embodiment shown in FIGS. 8A and 8B, two (plurality) convex portions 52A1 and 52A2 are formed as the convex portions 52A, and two (plurality) convex portions 52B1 and 52B2 are formed as the convex portions 52B. To form. Here, FIGS. 8A and 8B show the configurations of the convex portions 52A1, 52A2 (52B1, 52B2) and their vicinity in the state of FIG. 6 at the time of manufacture. Further, FIG. 8B shows a cross section of V3-V3 of FIG. 8A. In this embodiment, each of the convex portions 52A1, 52A2, 52B1, 52B2 is formed in the shape of a tunnel ceiling, similarly to the convex portions 52A and 52B of the first embodiment. Therefore, the longitudinal direction, the width direction, and the projecting direction are defined for each of the convex portions 52A1, 52A2, 52B1, and 52B2. Then, the longitudinal directions of the convex portions 52A1, 52A2, 52B1, 52B2 coincide with or substantially coincide with the vertical direction of the secondary battery 1, and the width directions of the convex portions 52A1, 52A2, 52B1, 52B2 are secondary. Match or substantially match the lateral direction of the battery 1. In each of the convex portions 52A1, 52A2, 52B1, 52B2, the cross-sectional shape perpendicular to or substantially vertical to the longitudinal direction is made uniform or substantially uniform over the entire length in the longitudinal direction. Further, in this embodiment, the cross-sectional shapes of the convex portions 52A1, 52A2, 52B1, 52B2 that are perpendicular to or substantially perpendicular to the longitudinal direction are formed in a substantially U-shape or a substantially semicircular arc shape. In FIG. 8B, each of the convex portions 52A1 and the convex portions 52A2 (52B1, 52B2) is shown in a cross section perpendicular to or substantially perpendicular to the longitudinal direction.

The convex portions (first convex portions) 52A1 and 52A2 are formed in a state of being close to each other. That is, the convex portion 52A1 is formed in the vicinity of the convex portion 52A2. The convex portions 52A1 and 52A2 are formed so as to extend in parallel or substantially parallel to each other. Further, the convex portions 52A1 and 52A2 are formed so as to be lined up along a specific direction. In this embodiment, the specific direction in which the convex portions 52A1 and 52A2 are lined up coincides with or substantially coincides with the lateral direction of the secondary battery 1, and is perpendicular or substantially perpendicular to the respective longitudinal directions of the convex portions 52A1 and 52A2. .. The convex portions 52A1 and 52A2 are formed in the same or substantially the same range as each other in the vertical direction of the secondary battery 1. Similarly, the convex portions (second convex portions) 52B1 and 52B2 are formed so as to be close to each other. That is, the convex portion 52B1 is formed in the vicinity of the convex portion 52B2. Then, the convex portions 52B1 and 52B2 are formed so as to extend in parallel or substantially parallel to each other. Further, the convex portions 52B1 and 52B2 are formed so as to be lined up along a specific direction. In this embodiment, the specific direction in which the convex portions 52B1 and 52B2 are lined up coincides with or substantially coincides with the lateral direction of the secondary battery 1, and is perpendicular or substantially perpendicular to the respective longitudinal directions of the convex portions 52B1 and 52B2. .. The convex portions 52B1 and 52B2 are formed in the same or substantially the same range as each other in the vertical direction of the secondary battery 1.

Each of the protrusions 52A1, 52A2, 52B1, 52B2 is formed in a dimension (corresponding one of D5a, D6a, D5b, D6b) in the longitudinal direction. The dimensions D5a, D6a, D5b, and D6b are the same or substantially the same size with respect to each other, and each of the dimensions D5a, D6a, D5b, and D6b is, for example, about 10 mm. Further, each of the convex portions 52A1, 52A2, 52B1 and 52B2 is formed in a width (corresponding one of W2a, W3a, W2b and W3b) in the width direction. The widths W2a, W3a, W2b, and W3b are the same or substantially the same size with respect to each other, and each of the widths W2a, W3a, W2b, and W3b is, for example, about 1.2 mm. Then, each of the convex portions 52A1, 52A2, 52B1, 52B2 is formed to a protruding dimension (corresponding one of P2a, P3a, P2b, P3b) up to the protruding end. The protruding dimensions P2a, P3a, P2b, and P3b are the same or substantially the same size with respect to each other, and each of the protruding dimensions P2a, P3a, P2b, and P3b is, for example, about 0.6 mm. Further, the convex portions 52A1 and 52A2 are formed so as to be separated from each other by a distance W4a in a predetermined direction in which the convex portions 52A1 and 52A2 are lined up, in the lateral direction of the secondary battery 1 in this embodiment. Similarly, the convex portions 52B1 and 52B2 are formed so as to be separated from each other by a distance W4b in a predetermined direction in which the convex portions 52B1 and 52B2 are lined up, in the lateral direction of the secondary battery 1 in this embodiment. The separation distances W4a and W4b are the same or substantially the same size with respect to each other, and the widths W4a and W4b are each about 0.6 mm, for example.

Further, in the third embodiment shown in FIGS. 9A to 9C, each of the convex portions 52A and 52B is formed in a dome shape. Here, FIGS. 9A to 9C show the configuration of the convex portion 52A (52B) and its vicinity in the state of FIG. 6 at the time of manufacture. 9B shows a V4-V4 cross section of FIG. 9A, and FIG. 9C shows a V5-V5 cross section of FIG. 9A. The cross section of FIG. 9B and the cross section of FIG. 9C are parallel or substantially parallel to the protruding direction of the convex portion 52A (52B), and are perpendicular or substantially perpendicular to each other. In this embodiment, as described above, each of the convex portions 52A and 52B is formed in a dome shape. Therefore, as shown in FIG. 9B, the cross-sectional shape of each of the secondary batteries 1 of the convex portions 52A and 52B is formed vertically or substantially vertically in the vertical direction in a substantially U-shape or a substantially semicircular arc shape. Then, as shown in FIG. 9C, a cross-sectional shape perpendicular to or substantially vertical to the lateral direction of each of the secondary batteries 1 of the convex portions 52A and 52B is formed in a substantially U shape or a substantially semicircular arc shape. That is, in each of the convex portions 52A and 52B, the cross-sectional shape is formed in a U-shape or a substantially semicircular arc shape in either a cross section parallel to or substantially parallel to the protruding direction.

In the present embodiment, when the second exterior member 6 is arranged to face the flange 13 as described above, as shown in FIG. 10, the flange 13 and the second exterior member 6 are arranged in a part of the circumferential direction of the opening 12. The exterior member 6 is airtightly welded. As a result, the welded portions 46 to 48 are formed before the electrolytic solution is injected into the storage space 11. At this time, welded portions 46 to 48 are formed by resistance seam welding. Further, before injecting the electrolytic solution, the flange 13 and the second exterior member 6 are not welded in a part of the circumferential direction of the opening 12. Therefore, in the state of FIG. 10, the welded portion is not formed in the range where the side wall 8A extends in the circumferential direction of the opening 12. Then, in the state of FIG. 10, the electrolytic solution is injected into the storage space 11 from the portion where the flange 13 and the second exterior member 6 are not welded. At this time, the electrolytic solution is injected from any part of the range in which the side wall 8A extends in the circumferential direction of the opening 12. The electrolytic solution is injected into the storage space 11 through the gap between the flange 13 and the second exterior member 6.

Then, after injecting the electrolytic solution, as shown in FIG. 11, the flange 13 and the second exterior member 6 are airtightly welded by resistance seam welding in a range where the opening is not welded in the circumferential direction. As a result, the welded portion 50 is formed. In the state of FIG. 11, in the flange 13 and the second exterior member 6, a welded portion 50 is formed at a portion protruding outward in the vertical direction from the side wall 8A. The welded portion 50 is formed so that one end is continuous with the welded portion 47 and the other end is continuous with the welded portion 48. Further, the welded portion 50 is formed on the outside of the opening holes 51A and the convex portions 52A and 52B, that is, on the side away from the opening 12. By forming the welded portion 50 as described above, the flange 13 and the second exterior member 6 are airtightly welded by the welded portions 46 to 48, 50 over the entire circumference in the circumferential direction of the opening 12. .. That is, welded portions (first welded portions) 46 to 48, 50 that airtightly weld the flange 13 and the second exterior member 6 over the entire circumference in the circumferential direction of the opening 12 are formed. Further, by forming the welded portion 50, the inside of the exterior portion 3 (storage space 11) is in a state of communicating with the outside of the exterior portion 3 only by the opening hole 51A. In the view of the secondary battery 1 such as FIG. 11 viewed from one side in the thickness direction, the welded portion 50 is shown by a broken line.

In the state of FIG. 11 in which the welded portion 50 is formed, the inside and the outside of the exterior portion 3 communicate with each other in the opening hole 51A. Therefore, in the state of FIG. 11, the internal pressure inside the exterior portion 3 (pressure in the storage space 11) is the same as or substantially the same as the external pressure outside the exterior portion 3. Then, in the state of FIG. 11, the flange 13 and the second exterior cover the entire or most of the region inside the welded portions 46 to 48, 50 and outside the edge 15 of the opening 12. A gap is formed between the member 6 and the member 6. At this time, in the region inside the welded portions 46 to 48, 50 and outside the edge 15 of the opening 12, for example, in a portion other than the protruding end of the convex portions 52A and 52B, the flange 13 is formed. It has a gap between it and the second exterior member 6 and does not adhere to the second exterior member 6.

In the embodiment in which the solid electrolyte sandwiched between the positive electrode 21 and the negative electrode 22 is used instead of the electrolytic solution, it may not be necessary to inject the electrolytic solution. In this case, the welded portions 46 to 48 may be formed after the welded portion 50 is formed. However, also in this embodiment, the flange 13 and the second exterior member 6 are airtightly welded by the welded portions (first welded portions) 46 to 48, 50 over the entire circumference in the circumferential direction of the opening 12. Weld.

Then, when the welded portion 50 is formed, the gas in the storage space 11 is discharged from the opening hole 51A to the outside of the exterior portion 3. That is, from the opening position (first opening position) between the welded portion (first welded portion) 50 and the convex portion (first convex portion) 52A and in the vicinity of the convex portion 52A, the storage space 11 Discharge the gas. At this time, as shown in FIG. 12, the suction pad 55 is attached to the outer surface of the exterior portion 3 at the opening hole (first opening position) 51A. The suction pad 55 is connected to a pump 57 such as a vacuum pump via a suction tube 56. A valve 61 and a vacuum regulator 62 are arranged in the suction path between the pump 57 and the suction pad 55. When the gas is discharged from the opening hole 51A, the suction pad 55 is attached to the exterior portion 3, and then the pump 57 is driven to open the valve 61. As a result, inside the exterior portion 3, gas flows from the storage space 11 to the opening hole 51A through the gap between the flange 13 and the second exterior member 6. Then, the gas is sucked into the suction tube 56 from the opening hole 51A, and the gas flows toward the pump 57 through the inside of the suction tube 56. As a result, gas is discharged from the opening hole 51A to the outside of the exterior portion 3. The discharge from the opening hole 51A is performed in an environment where the dew point temperature is −50 ° C. or lower.

Then, when the gas is discharged from the opening hole 51A to the outside of the exterior portion 3 and the internal pressure inside the exterior portion 3 such as the pressure of the storage space 11 drops to a certain extent, as shown in FIG. 13, the opening hole (first) The flange 13 and the second exterior member 6 are airtightly welded between the opening position) 51A and the convex portion 52A. That is, a welded portion 53A is formed between the opening hole 51A and the convex portion 52A. The welded portion 53A is formed so as to be inclined with respect to the vertical direction and the horizontal direction of the secondary battery 1. The welded portion 53A is formed so that one end is continuous with the welded portion 50 and the other end is continuous with the welded portion 47. By forming the welded portion 53A, the gas path is blocked between the opening hole (first opening position) 51A and the convex portion (first convex portion) 52A. The welded portion 53A is formed by, for example, resistance seam welding, similarly to the welded portions 46 to 48, 50. Further, in the view of the secondary battery 1 such as FIG. 13 viewed from one side in the thickness direction, the welded portion 53A is shown by a broken line.

By forming the welded portion 53A, in the portion inside the opening hole 51A, the welded portions 46 to 48, 50, 53A cover the entire circumference of the opening 12 in the circumferential direction of the flange 13 and the second. The exterior member 6 is airtightly welded. As a result, the storage space 11 in which the electrode group 10 is housed is sealed with respect to the outside of the exterior portion 3.

When the welded portion 53A is formed, the portion of the flange 13 and the second exterior member 6 outside the welded portions 46 to 48 is cut. Then, the secondary battery 1 is charged (initially charged) and aged. As a result, gas is generated in the storage space 11 in which the electrode group 10 is housed. When aging is performed as described above, it is necessary to discharge the gas generated by the aging to the outside of the exterior portion 3. The aging temperature is preferably in the range of 70 ° C. or higher and 90 ° C. or lower.

Therefore, as shown in FIG. 14, an opening hole 51B is formed in one of the flange 13 and the second exterior member 6. The opening hole 51B is formed on the inner side of the welded portion (first welded portion) 50, that is, on the side closer to the opening 12. The opening hole 51B is formed on the outside of the convex portion 52B, that is, on the side far from the opening 12. That is, an opening hole 51B is formed between the welded portion 50 and the convex portion 52B. At this time, the opening hole 51B is formed to have a diameter of φb. The diameter φb of the opening hole 51B is the same as or substantially the same size as the diameter φa of the opening hole 51A, and is, for example, about 1 mm. Further, the opening hole (second opening hole) 51B is formed at a position separated from the edge 15 of the opening 12 by a distance D1b. The distance D1b has the same or substantially the same size as the distance D1a, and is, for example, about 20 mm. Further, the operator forms an opening hole 51B in the vicinity of the convex portion 52B. At this time, the opening hole 51B is formed so that the distance D2b from the convex portion 52B to the opening hole 51B is 6 mm or less. Further, the opening hole 51B is formed at a position away from the opening hole 51A and the convex portion 52A in the lateral direction of the secondary battery 1. In forming the opening hole 51B, first, a through hole is formed in both the flange 13 and the second exterior member 6. Then, one of the two through holes is airtightly closed. As a result, one of the two unclosed through holes is used as the opening hole 51B.

When the opening hole 51B is formed, the gas in the storage space 11 is discharged from the opening hole 51B to the outside of the exterior portion 3. That is, from the opening position (second opening position) between the welded portion (first welded portion) 50 and the convex portion (second convex portion) 52B and in the vicinity of the convex portion 52B, the storage space 11 Discharge the gas. At this time, the gas is discharged from the opening hole 51B by using the suction pad 55, the suction tube 56, the pump 57, the valve 61, the vacuum regulator 62, etc., as in the case of discharging the gas from the opening hole (first opening position) 51A. Discharge. At this time, inside the exterior portion 3, gas flows from the storage space 11 to the opening hole 51B through the gap between the flange 13 and the second exterior member 6. Then, the gas is sucked into the suction tube 56 from the opening hole 51B, and the gas flows toward the pump 57 through the inside of the suction tube 56. As a result, gas is discharged from the opening hole 51B to the outside of the exterior portion 3. The discharge from the opening hole (second opening position) 51B is also performed in an environment where the dew point temperature is −50 ° C. or lower.

Then, when the gas is discharged to the outside of the exterior portion 3 from the opening hole 51B and the internal pressure inside the exterior portion 3 such as the pressure of the storage space 11 drops to a certain extent, as shown in FIG. 15, the opening hole (second). The flange 13 and the second exterior member 6 are airtightly welded between the opening position) 51B and the convex portion 52B. That is, a welded portion 53B is formed between the opening hole 51B and the convex portion 52B. The welded portion 53B is formed so as to be inclined with respect to the vertical direction and the horizontal direction of the secondary battery 1. The welded portion 53B is formed so that one end is continuous with the welded portion 50 and the other end is continuous with the welded portion 48. By forming the welded portion 53B, the gas path is blocked between the opening hole (second opening position) 51B and the convex portion (second convex portion) 52B. The welded portion 53B is formed by, for example, resistance seam welding, similarly to the welded portions 46 to 48, 50, 53B. Further, in the view of the secondary battery 1 such as FIG. 15 viewed from one side in the thickness direction, the welded portion 53B is shown by a broken line.

By forming the welded portion 53B, the flange 13 is formed at a portion inside the opening holes 51A and 51B by the welded portions 46 to 48, 50, 53A and 53B over the entire circumference in the circumferential direction of the opening 12. And the second exterior member 6 is airtightly welded. As a result, the storage space 11 in which the electrode group 10 is housed is resealed with respect to the outside of the exterior portion 3. When the welded portion 53B is formed, the capacity of the secondary battery 1 is confirmed.

Then, as shown in FIG. 16, the flange 13 and the second exterior member 6 are airtightly welded inside the convex portions 52A and 52B to form a welded portion (second welded portion) 45. The welded portion 45 is formed after both the gas is discharged from the opening hole (first opening position) 51A and the gas is discharged from the opening hole (second opening position) 51B. The weld 45 is formed on the outside of the edge 15 of the opening 12 by resistance seam welding. Further, the welded portion 45 is formed so that one end is continuous with the welded portion 47 and the other end is continuous with the welded portion 48. In the present embodiment, the welded portion 45 is formed in the flange 13 and the second exterior member 6 at a portion protruding outward in the vertical direction from the side wall 8A, and extends along the lateral direction of the secondary battery 1. .. By forming the welded portion (second welded portion) 45, between the edge 15 of the opening 12 and the convex portion (first convex portion) 52A, and between the edge 15 of the opening 12 and the convex portion (second convex portion). The gas path is cut off from the convex portion) 52B.

Then, the portion of the flange 13 and the second exterior member 6 outside the welded portion 50 is cut. As a result, as shown in FIG. 5, the opening holes (opening positions) 51A and 51B and the convex portions 52A and 52B are removed. Even if the portion outside the welded portion 50 is cut, the flange 13 and the second exterior member 6 are airtightly welded by the welded portions 45 to 48 over the entire circumference in the circumferential direction of the opening 12. Therefore, even if the portion outside the welded portion 50 is cut, the storage space 11 in which the electrode group 10 is arranged is sealed with respect to the outside of the exterior portion 3. As described above, the secondary battery 1 is manufactured.

In some embodiments, the welded portion 45 is not formed. In this case, the flange 13 and the second exterior member 6 are airtightly welded to the outside by the welded portions 46 to 48, 50, 53A, 53B over the entire circumference in the circumferential direction of the opening 12. Is sealed. Further, in this embodiment, the manufactured secondary battery 1 is provided with convex portions 52A and 52B and opening holes 51A and 51B.

Further, in another embodiment in which the welded portion 45 is not formed, after the welded portion 53A is formed at the time of manufacturing, the portion outside the welded portion 53A is cut in the flange 13 and the second exterior member 6. As a result, the opening hole 51A is removed, and the manufactured secondary battery 1 is not provided with the opening hole 51A. Similarly, in another embodiment in which the welded portion 45 is not formed, after the welded portion 53B is formed at the time of manufacturing, the portion outside the welded portion 53B is cut in the flange 13 and the second exterior member 6. As a result, the opening hole 51B is removed, and the manufactured secondary battery 1 is not provided with the opening hole 51B. Further, in another embodiment in which the welded portion 45 is not formed, the portion outside the welded portion 53A and the portion outside the welded portion 53B are cut at the time of manufacturing, and the manufactured secondary battery 1 is subjected to Both opening holes 51A and 51B are not provided.

As described above, in the production of the secondary battery 1, the gas is discharged from the opening hole 51A and the gas is discharged from the opening hole 51B. When the gas is discharged to the outside of the exterior portion 3, the pressure in the storage space 11, that is, the internal pressure inside the exterior portion 3 decreases. As a result, the internal pressure inside the exterior portion 3 is lower than the external pressure outside the exterior portion 3. Since the internal pressure is lower than the external pressure, the flange 13 and the second exterior member 6 are in close contact with each other at the portion separated from the convex portions 52A and 52B. However, in the present embodiment, the convex portions 52A and 52B are provided on one of the flange 13 and the second exterior member 6, and the flange 13 and the second exterior member 6 are formed of stainless steel. Therefore, even when the internal pressure is lower than the external pressure, the flange 13 has a gap with respect to the second exterior member 6 in the vicinity of the protruding end of the convex portion 52A, and is in close contact with the second exterior member 6. do not. Similarly, even when the internal pressure is lower than the external pressure, the flange 13 has a gap with respect to the second exterior member 6 in the vicinity of the protruding end of the convex portion 52B, and is in close contact with the second exterior member 6. do not. At this time, at the protruding ends of the convex portions 52A and 52B, the flange 13 comes into contact with the second exterior member 6.

FIG. 17 shows the convex portion 52A (52B) and its vicinity in a state where the internal pressure inside the exterior portion 3 is lower than the external pressure outside the exterior portion 3 in the configuration of the first embodiment described above. In FIG. 17, the convex portion 52A (52B) is shown in a cross section perpendicular to or substantially vertical to the longitudinal direction. As shown in FIG. 17, in the first embodiment, even if the internal pressure is lower than the external pressure, the flange 13 is attached to the second exterior member 6 in the vicinity of the protruding ends of the convex portions 52A and 52B. On the other hand, it has a gap and does not adhere to the second exterior member 6. Further, in the third embodiment as in the first embodiment, even if the internal pressure is lower than the external pressure, the flange 13 is the second exterior in the vicinity of the protruding ends of the convex portions 52A and 52B. It has a gap with respect to the member 6 and does not adhere to the second exterior member 6.

In the present embodiment in which the convex portions 52A and 52B are provided as described above, the flange 13 is a second exterior member in the vicinity of the protruding ends of the convex portions 52A and 52B regardless of the magnitude of the external pressure and the internal pressure. It has a gap with respect to 6 and does not adhere to the second exterior member 6. Therefore, even if the internal pressure becomes lower than the external pressure due to suction from one of the opening holes (opening positions) 51A and 51B, the gas path is blocked in the vicinity of the protruding ends of the convex portions 52A and 52B. Secured without. As a result, even when the internal pressure is lower than the external pressure during manufacturing, the gas path from the storage space 11 to the opening hole (corresponding one of 51A and 51B) is not blocked, and the convex portion (48A, 48A,) from the storage space 11 is not blocked. The gas easily flows to the opening hole (the corresponding one of 51A and 51B) through the vicinity of the protruding end of (the corresponding one of 48B). Therefore, even if the internal pressure is lower than the external pressure, the gas reaches the opening hole (corresponding one of 51A and 51B), and the gas is appropriately discharged from the opening hole (corresponding one of 51A and 51B). As described above, the gas is appropriately discharged from the opening holes 51A and 51B during manufacturing, so that in the manufactured secondary battery 1, almost no gas remains inside the exterior portion 3, that is, in the storage space 11. .. As a result, the secondary battery 1 having a low internal resistance and a long life is manufactured.

FIG. 18 shows the convex portions 52A1, 52A2 (52B1, 52B2) and the convex portions 52A1, 52B2 in the configuration of the second embodiment described above, in a state where the internal pressure inside the exterior portion 3 is lower than the external pressure outside the exterior portion 3. Indicates the neighborhood. In FIG. 18, the convex portions 52A1, 52A2 (52B1, 52B2) are shown in a cross section perpendicular to or substantially vertical to the longitudinal direction. As shown in FIG. 18, in the second embodiment as well as in the first embodiment and the third embodiment, even if the internal pressure is lower than the external pressure, the convex portions 52A1, 52A2, 52B1, 52B2, respectively. In the vicinity of the protruding end of the flange 13, the flange 13 has a gap with respect to the second exterior member 6 and does not come into close contact with the second exterior member 6. Therefore, as described above, even if the internal pressure is lower than the external pressure, the gas reaches the opening hole (corresponding one of 51A and 51B), and the gas is released from the opening hole (corresponding one of 51A and 51B). It is discharged.

Further, in the second embodiment, since the convex portions 52A1 and 52A2 are close to each other, even if the internal pressure is lower than the external pressure, the second flange 13 is located between the protruding ends of the convex portions 52A1 and 52A2. The gap with respect to the exterior member 6 of the above is maintained large. Similarly, in the second embodiment, since the convex portions 52B1 and 52B2 are close to each other, even if the internal pressure is lower than the external pressure, the flange 13 is located between the protruding ends of the convex portions 52B1 and 52B2. The gap of 2 with respect to the exterior member 6 is largely maintained. As a result, in the second embodiment, the seal is opened from the storage space 11 through the vicinity of the protruding ends of the convex portions 52A1 and 52A2 or the vicinity of the protruding ends of the convex portions 52B1 and 52B2 in a state where the internal pressure is lower than the external pressure. The gas becomes easier to flow into the holes (corresponding one of 51A and 51B). Therefore, in the second embodiment, the gas is more effectively discharged to the outside of the exterior portion 3 from the opening holes (corresponding one of 51A and 51B).

(Verification related to Examples)
Here, the actions and effects of the above-described embodiments have been verified. FIG. 19 shows a system used for verification regarding the decompression state of the storage space 11 in the manufacture of the secondary battery 1. As shown in FIG. 19, in the verification, a subject 1 ′ simulating the above-mentioned secondary battery 1 was formed. In the subject 1', the exterior portion 3'was formed by the first exterior member 5'and the second exterior member 6'made of stainless steel. In the first exterior member 5', a bottom wall 7'and side walls 8'A to 8'D are formed in the same manner as the above-mentioned first exterior member 5, and a storage space 11'is defined. Further, the storage space 11'was opened with an opening 12', similarly to the first exterior member 5. Then, a flange 13'was formed on the first exterior member 5'as in the case of the first exterior member 5, and the edge 15'of the opening 12'of the storage space 11' was defined by the flange 13'. Further, the second exterior member 6'was formed in a plate shape in the same manner as the above-mentioned second exterior member 6. Then, the second exterior member 6'is arranged so as to face the flange 13', and the opening 12'is closed by the second exterior member 6'. Further, the wall thickness of each of the first exterior member 5'and the second exterior member 6'was formed to be 0.1 mm.

Further, in the subject 1', welded portions 46' to 48', 50'similar to the welded portions 46 to 48, 50 described above are formed by resistance seam welding, and the entire circumference of the opening 12'is formed over the entire circumference. , Flange 13'and second exterior member 6'welded airtightly. Further, in the subject 1', the opening hole 51'A was formed at the same position as the opening hole 51A described above on the flange 13'. The opening hole 51'A was formed inside the welded portion 50'. Further, in the opening hole 51'A, the diameter φ'a was formed to 1 mm, and the distance D'1a from the edge 15'of the opening 12' to the opening hole 51'A was set to 20 mm. The subject 1'corresponds to the opening hole corresponding to the opening hole 51B, the convex portion corresponding to the convex portion 52B (including 52B1 and 52B2) described above, and the welded portions 45, 53A and 53B described above. No welded part is formed.

In the verification, the gas in the storage space 11'was discharged from the opening hole 51'A to the outside of the exterior portion 3'. The gas was discharged in an environment where the dew point temperature was −60 ° C. At this time, the gas is discharged to the outside of the exterior portion 3'using the suction pad 55, the suction tube 56, the pump 57, the valve 61, and the vacuum regulator 62, as in the case of discharging the gas at the time of manufacturing the secondary battery 1 described above. Was discharged. As the suction pad 55, a flat pad manufactured by Misumi Co., Ltd., of which model ZP2-B10MTF was used. As the pump 57, a model DA41D manufactured by ULVAC, with an effective exhaust speed of 40 L / min (0.67 L / sec), an ultimate pressure of −98 kPa, and a set pressure of the vacuum regulator 62 of −100 kPa was used. Further, in the verification, the attachment 65 was attached to the bottom wall 7'of the first exterior member 5', and the attachment 65 was connected to the pressure sensor 67 via the tube 66. Then, while the gas was being discharged from the opening hole 51'A, the pressure of the storage space 11', that is, the internal pressure inside the exterior portion 3'was measured by the pressure sensor 67. The attachment 65 was attached at a diagonal position with respect to the opening hole 51'A, that is, near the corner formed by the side walls 8'B and 8'D. As the attachment 65, a model M3-ALU-4 manufactured by SMC Corporation was used. Further, as the pressure sensor 67, a pressure sensor 67 manufactured by Keyence Corporation and having a rated pressure range of ± 100 kPa was used.

In the verification, gas was discharged from the opening hole 51'A under three conditions α1 to α3, and the change over time in the decompression degree ε of the storage space 11'from the start of gas discharge was measured. The change over time in the degree of decompression ε was measured twice for each of the conditions α1 to α3. Here, under the condition α1, only the opening hole 51 ′ A is provided in the region outside the edge 15 ′ of the opening 12 ′ and inside the welded portions 46 ′ to 48 ′, 50 ′. Therefore, under the condition α1, a configuration or the like corresponding to the above-mentioned convex portion 52A (including 52A1 and 52A2) is not provided. Under the condition α2, in the region outside the edge 15 ′ of the opening 12 ′ and inside the welded portions 46 ′ to 48 ′, 50 ′, in addition to the opening hole 51 ′ A, the above-mentioned first embodiment A convex portion 52'A similar to the convex portion 52A (see FIGS. 7A to 7C) was provided on the flange 13'. The convex portion 52'A is formed in the same tunnel ceiling shape as the convex portion 52A, and is formed at the same position as the convex portion 52A. Further, the convex portion 52'A has a dimension D'4a in the longitudinal direction of 10 mm and a width W'1a in the width direction of 1.2 mm. Then, the convex portion 52'A has a protruding dimension P'1a of 0.4 mm. The distance D'2a from the convex portion 52'A to the opening hole 51'A was set to 6 mm, and the distance D'3a from the edge 15'of the opening 12'to the convex portion 52'A was set to 4 mm.

Under the condition α3, in the region outside the edge 15 ′ of the opening 12 ′ and inside the welded portions 46 ′ to 48 ′, 50 ′, in addition to the opening hole 51 ′ A, the above-mentioned second embodiment Convex portions 52'A1, 52'A2 similar to the convex portions 52A1, 52A2 (see FIGS. 8A and 8B) are provided on the flange 13'. The convex portion 52'A1 is formed in the same tunnel ceiling shape as the convex portion 52A1 and at the same position as the convex portion 52A1. The convex portion 52'A2 is formed in the same tunnel ceiling shape as the convex portion 52A2 and at the same position as the convex portion 52A2. Each of the convex portions 52'A1 and 52'A2 has a longitudinal dimension (corresponding one of D'5a and D'6a) of 10 mm, and a width in the width direction (W'2a and W'3a). The corresponding one) was formed to 1.2 mm. Further, each of the convex portions 52'A and 52'A2 has a protruding dimension (the corresponding one of P'2a and P'3a) formed to 0.6 mm. Further, the distance D'2a from the convex portions 52'A1, 52'A2 to the opening hole 51'A is set to 6 mm, and the distance D'3a from the edge 15'of the opening 12' to the convex portions 52'A1, 52'A2. Was set to 4 mm. Then, the separation distance W'4a between the convex portions 52'A1 and 52'A2 was set to 0.6 mm.

FIG. 20 shows the measurement result of the change with time of the decompression degree ε of the storage space 11'in the verification. In FIG. 20, the horizontal axis represents the time t based on the start of gas discharge from the opening hole 51'A, and the vertical axis represents the degree of decompression ε. Further, in FIG. 20, the first measurement under the condition α1, the second measurement under the condition α1, the first measurement under the condition α2, the second measurement under the condition α2, and the first measurement under the condition α3. And, the change with time of the decompression degree ε in the second measurement under the condition α3 is shown.

As shown in FIG. 20, under the condition α1, the degree of decompression ε was −70 kPa or more and -60 kPa or less when 5 minutes had passed from the start of gas discharge. That is, under the condition α1, the decompression degree ε did not reach −90 kPa even after 5 minutes had passed from the start of gas discharge. In the verification, after the gas was discharged for 5 minutes under the condition α1, the flange 13 ′ and the second exterior member 6 ′ were pulled in a direction away from each other by a mechanical force. At this time, the flange 13 ′ and the second exterior member 6 ′ were mechanically pulled between the edge 15 ′ of the opening 12 ′ and the opening hole 51 ′ A. In the verification, even if the flange 13'and the second exterior member 6'were mechanically pulled, the degree of decompression ε hardly changed and was maintained at −70 kPa or more and -60 kPa or less. That is, even if the flange 13'and the second exterior member 6'were mechanically pulled, the degree of decompression ε did not reach −90 kPa.

Further, under the condition α2, the decompression degree ε became −90 kPa when 3 minutes had passed from the start of gas discharge. Therefore, in the configuration of the first embodiment or the like in which the convex portion 52A (52B) similar to the convex portion 52'A is provided, even if the internal pressure is lower than the external pressure, the opening holes (51A, 51B correspond to each other). ), And it was verified that the gas was properly discharged to the outside of the exterior portion 3.

Further, under the condition α3, the degree of decompression ε became −90 kPa or less when 1 minute had passed from the start of gas discharge. Therefore, in the configuration of the second embodiment in which the convex portions 52A1, 52A2 (52B1, 52B2) similar to the convex portions 52'A1, 52'A2 are provided, the internal pressure is lower than the external pressure from the storage space 11. It was verified that the gas became easier to flow into the opening holes 51A and 51B), and the gas was more effectively discharged to the outside of the exterior portion 3.

(Modification example)
In the above-described embodiment, gas is discharged to the outside from the opening hole (first opening position) 51A before charging and aging, and gas is discharged from the opening hole (second opening position) 51B after charging and aging. Is discharged to the outside, but it is not limited to this. In one modification, gas is discharged to the outside from the opening hole (second opening position) 51B before charging and aging, and gas is discharged to the outside from the opening hole (first opening position) 51A after charging and aging. It is discharged. In this case, in the production of the secondary battery 1, an opening hole (second opening hole) 51B is formed in the flange 13 in the formation of the flange 13, or a second exterior member 6 is formed in the formation of the second exterior member 6. The opening hole 51B is formed in the opening hole 51B. Then, after the gas is discharged from the opening hole 51B, the welded portion 53B is formed, and the storage space 11 is sealed to the outside of the exterior portion 3 by the welded portions 46 to 48, 50, 53B. Then, after aging or the like, the opening hole (first opening hole) 51A is formed in a state where the storage space 11 is sealed by the welded portions 46 to 48, 50, 53B. Then, the gas generated by aging is discharged to the outside of the exterior portion 3 from the formed opening hole 51A. Then, when the gas is discharged from the opening hole 51A, the welded portion 53A is formed, and the storage space 11 is sealed again with respect to the outside of the exterior portion 3 by the welded portions 46 to 48, 50, 53A, 53B.

Further, in the manufacturing method such as the above-described embodiment, the secondary battery 1 in which only one electrode group 10 is stored in the storage space 11 is manufactured, but in a modified example, a plurality of electrode groups are stored in the storage space 11. The stored secondary battery 1 is also manufactured in the same manner as in the above-described embodiment.

Further, in a modified example, the second exterior member 6 is formed not in a plate shape but in a tubular shape with a bottom similar to that of the first exterior member 5. In this case, the second exterior member 6 is also formed so as to include the bottom wall, the side wall, and the flange. Then, the flange 13 of the first exterior member 5 and the flange of the second exterior member 6 are airtightly welded at the welded portions 45 to 48 and the like. Even in the secondary battery 1 manufactured by the manufacturing method of this modification, the flange 13 and the second exterior member 6 are airtightly welded by the welded portions 45 to 48 over the entire circumference in the circumferential direction of the opening 12. .. Then, the storage space 11 in which the electrode group 10 is housed is sealed with respect to the outside of the exterior portion 3.

According to the method for manufacturing the secondary battery of at least one of these embodiments or examples, the second exterior member has a convex portion protruding from one of the flange and the second exterior member to the other, and the convex portion is formed. It is arranged so as to face the flange of the first exterior member so as to be located outside the edge of the opening. Then, the flange and the second exterior member are airtightly welded at the welded portion on the outside of the convex portion, and the gas in the storage space is discharged from the opening position between the welded portion and the convex portion and near the convex portion. .. Therefore, it is possible to provide a method for manufacturing a secondary battery in which gas is appropriately discharged from the storage space to the outside during manufacturing.

Although some embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other embodiments, and various omissions, replacements, and changes can be made without departing from the gist of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are included in the scope of the invention described in the claims and the equivalent scope thereof.

Claims (14)

The first exterior member is formed of stainless steel so that the storage space is defined by the bottom wall and the side wall, and the storage space has an opening on the side opposite to the bottom wall.
In the formation of the first exterior member, a flange is formed at a portion opposite to the bottom wall, and the flange is formed in a state where the flange defines the edge of the opening of the storage space. That and
Forming a group of electrodes having a positive electrode and a negative electrode,
Forming a second exterior member from stainless steel and
In the formation of the flange, a first convex portion is formed on the flange, or in the formation of the second exterior member, a first convex portion is formed on the second exterior member.
The second exterior member is arranged to face the flange in a state where the electrode group is arranged in the storage space to close the opening of the storage space, and the flange and the second exterior are closed. The first convex portion formed on one of the members is arranged outside the edge of the opening, and the first convex portion projects toward the other of the flange and the second exterior member. By arranging the second exterior member in the state,
The flange and the second exterior member are airtightly welded on the outside of the first convex portion over the entire circumference of the opening to form the first welded portion.
Discharging the gas in the storage space between the first welded portion and the first convex portion and from the first opening position in the vicinity of the first convex portion.
A method for manufacturing a secondary battery. The manufacturing method according to claim 1, wherein forming the first convex portion comprises forming the first convex portion in a tunnel ceiling shape. The manufacturing method according to claim 1, wherein forming the first convex portion comprises forming the first convex portion in a dome shape. The manufacturing method according to claim 1, wherein forming the first convex portion comprises forming a plurality of first convex portions in a state of being close to each other and arranging in a predetermined direction. Forming the plurality of first convex portions comprises forming each of the plurality of first convex portions in a tunnel ceiling shape.
Forming the plurality of first convex portions means that the plurality of first convex portions are extended in parallel or substantially parallel to each other, and the plurality of first convex portions are lined up. The plurality of first convex portions are formed in a state in which the direction is perpendicular to or substantially perpendicular to the longitudinal direction of each of the plurality of convex portions.
The method for manufacturing a secondary battery according to claim 4. Forming the first exterior member comprises forming the first exterior member with a wall thickness of 0.02 mm or more and 0.3 mm or less.
Forming the second exterior member includes forming the second exterior member with a wall thickness of 0.02 mm or more and 0.3 mm or less.
The production method according to any one of claims 1 to 5. After the gas is discharged from the first opening position, the flange and the second exterior member are airtightly welded between the first opening position and the first convex portion, and the first The production method according to any one of claims 1 to 6, further comprising blocking the gas path between the opening position and the first convex portion. It further comprises injecting an electrolytic solution into the storage space while the electrode group is stored in the storage space.
Forming the first weld
Before injecting the electrolytic solution, the flange and the second exterior member are airtightly welded only in a part of the circumferential direction of the opening.
After injecting the electrolytic solution from a portion where the flange and the second exterior member are not welded, the flange and the second exterior member are airtightly provided in a range where the flange and the second exterior member are not welded in the circumferential direction of the opening. Welding and
The production method according to any one of claims 1 to 7, further comprising. Further comprising forming an opening hole in the flange in the formation of the flange, or forming an opening hole in the second exterior member in the formation of the second exterior member.
Placing the second exterior member so as to face the flange means that the opening hole is located outside the first convex portion and in the vicinity of the first convex portion. With the placement of 2 exterior members
Forming the first welded portion comprises forming the first welded portion on the outside of the opening hole.
Discharging the gas from the first opening position comprises discharging the gas from the opening at the first opening position.
The production method according to any one of claims 1 to 8. After forming the first welded portion, it further comprises forming an opening hole between the first welded portion and the first convex portion and in the vicinity of the first convex portion. ,
Discharging the gas from the first opening position comprises discharging the gas from the opening at the first opening position.
The production method according to any one of claims 1 to 8. After the gas is discharged from the first opening position, the flange and the second exterior member are airtightly welded inside the first convex portion to form a second welded portion. The second weld blocks the gas path between the edge of the opening and the first protrusion.
In the flange and the second exterior member, a portion outside the second welded portion is cut to remove the first convex portion and the first opening position.
The production method according to any one of claims 1 to 10, further comprising. In the formation of the flange, a second convex portion is formed at a position away from the first convex portion of the flange, or in the formation of the second exterior member, the first convex portion of the second exterior member is formed. Forming a second convex part at a position away from the convex part,
Arranging the second exterior member so as to face the flange means that the second convex portion formed on one of the flange and the second exterior member is arranged outside the edge of the opening. The second exterior member is arranged so that the second convex portion projects toward the other side of the flange and the second exterior member.
Forming the first welded portion comprises forming the first welded portion on the outside of the second convex portion.
In the manufacturing method, the first welded portion and the second convex portion are formed before the gas is discharged from the first opening position or after the gas is discharged from the first opening position. Further provided, the gas in the storage space is discharged between the two, and from the second opening position in the vicinity of the second convex portion.
The production method according to any one of claims 1 to 10. After the gas is discharged from the second opening position, the flange and the second exterior member are airtightly welded between the second opening position and the second convex portion, and the second The manufacturing method according to claim 12, further comprising blocking the path of the gas between the opening position and the second convex portion. After both discharging the gas from the first opening position and discharging the gas from the second opening position, inside the first convex portion and the second convex portion. A second welded portion is formed by airtightly welding the flange and the second exterior member, and the second welded portion provides an interval between the edge of the opening and the first convex portion. And blocking the gas path between the edge of the opening and the second protrusion.
In the flange and the second exterior member, a portion outside the second welded portion is cut, and the first convex portion, the second convex portion, the first opening position, and the second opening are opened. Removing the position and
The manufacturing method according to claim 12 or 13.

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