CN111052442A

CN111052442A - Method for manufacturing secondary battery

Info

Publication number: CN111052442A
Application number: CN201780094287.0A
Authority: CN
Inventors: 间明田博清; 桥本达也
Original assignee: Toshiba Corp
Current assignee: Toshiba Corp
Priority date: 2017-12-27
Filing date: 2017-12-27
Publication date: 2020-04-21
Anticipated expiration: 2037-12-27
Also published as: WO2019130502A1; JP6862577B2; CN111052442B; JPWO2019130502A1

Abstract

In the manufacturing method of the embodiment, the first outer package member defining the housing space by the bottom wall and the side wall and defining the edge of the opening of the housing space by the flange on the side opposite to the bottom wall is formed, and the second outer package member is opposed to the flange in a state where the electrode group is arranged in the housing space. A convex portion protruding toward the other is formed on one of the flange and the second outer jacket material, and the convex portion is disposed in a state of being positioned outside the edge of the opening. In the manufacturing method, the flange and the second outer package member are hermetically welded by the welded portion outside the convex portion, and the gas in the housing space is discharged from the unsealing position between the welded portion and the convex portion and in the vicinity of the convex portion.

Description

Method for manufacturing secondary battery

Technical Field

Embodiments of the present invention relate to a method of manufacturing a secondary battery.

Background

In general, a secondary battery includes an electrode group including a positive electrode and a negative electrode, and an exterior package housing the electrode group. In addition, there is a secondary battery in which the exterior cover is formed of two exterior members, and each of the two exterior members is formed of stainless steel. In this secondary battery, the first outer package member, which is one of the outer packages, is formed in a bottomed tubular shape including a bottom wall and a side wall, and a housing space for housing the electrode group is defined by the bottom wall and the side wall. The storage space has an opening on the side opposite to the bottom wall. In the first outer package portion, a flange is formed at a portion on the opposite side of the bottom wall, and the flange defines an edge of an opening of the housing space. In the secondary battery, the second outer jacket material is disposed so as to face the flange and closes the opening of the housing space. Further, a welding portion for airtightly welding the flange and the second exterior member is formed outside the edge of the opening. The welded portion is formed over the entire circumference of the opening. The housing space is sealed from the outside by the welding portion.

In the secondary battery as described above, in order to prevent an increase in internal resistance and a decrease in life, it is required to discharge gas from the housing space during manufacturing. In addition, in manufacturing, it is required to hermetically weld the flange and the second exterior member in a state where gas is discharged from the housing space, and to seal the housing space from the outside.

Documents of the prior art

Patent document

Patent document 1: international publication No. 2016/204147

Disclosure of Invention

Problems to be solved by the invention

The present invention has been made to solve the problem, and an object of 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.

Means for solving the problems

According to an embodiment, a method for manufacturing a secondary battery includes: forming an electrode group including a positive electrode and a negative electrode; and forming the first outer package member and the second outer package member from stainless steel. The first outer cover member is formed such that a housing space is defined by the bottom wall and the side wall, and the housing space is opened on the side opposite to the bottom wall. In the formation of the first outer jacket material, a flange is formed at a portion on the opposite side of the bottom wall, and the flange is formed in a state where the flange defines an edge of the opening of the housing space. In the manufacturing method, the convex portion is formed as the flange in the formation of the flange or as the second outer jacket material in the formation of the second outer jacket material. In the manufacturing method, the second outer jacket material is disposed to face the flange in a state where the electrode group is disposed in the housing space, and the opening of the housing space is closed. In this case, the second outer jacket material is disposed in a state in which the protruding portion formed on one of the flange and the second outer jacket material is disposed outside the edge of the opening and the protruding portion protrudes toward the other of the flange and the second outer jacket material. In the manufacturing method, the flange and the second outer cover member are hermetically welded to the outside of the projection over the entire periphery of the opening, thereby forming a welded portion. In the manufacturing method, the gas in the housing space is discharged from the unsealing position between the welding portion and the convex portion and in the vicinity of the convex portion.

Drawings

Fig. 1 is a perspective view schematically showing an example of a secondary battery manufactured by the manufacturing method of the first embodiment.

Fig. 2 is a perspective view schematically showing the secondary battery of fig. 1 in a state in which the first outer package member, the second outer package member, and the electrode group are exploded with respect to each other.

Fig. 3 is a schematic diagram illustrating the structure of the electrode group of the secondary battery of fig. 1.

Fig. 4 is a schematic diagram showing a structure in which the secondary battery of fig. 1 is electrically connected to a positive electrode terminal (negative electrode terminal) of an electrode group.

Fig. 5 is a schematic view of the secondary battery of fig. 1 as viewed from the side of the bottom wall of the first outer jacket material in the thickness direction.

Fig. 6 is a schematic view showing a state in which the second outer jacket material is disposed so as to face the flange when the secondary battery is manufactured by the manufacturing method of the first embodiment.

Fig. 7A is a schematic view showing the state of fig. 6 when the configuration of the convex portion and the vicinity thereof in the first example of the first embodiment is manufactured.

FIG. 7B is a cross-sectional view schematically showing the section V1-V1 of FIG. 7A.

FIG. 7C is a sectional view schematically showing the section V2-V2 of FIG. 7A.

Fig. 8A is a schematic view showing the state of fig. 6 when the configuration of the convex portion and the vicinity thereof in the second example of the first embodiment is manufactured.

FIG. 8B is a sectional view schematically showing the section V3-V3 of FIG. 8A.

Fig. 9A is a schematic view showing the state of fig. 6 when the configuration of the convex portion and the vicinity thereof in the third example of the first embodiment is manufactured.

FIG. 9B is a sectional view schematically showing the section V4-V4 of FIG. 9A.

FIG. 9C is a sectional view schematically showing the section V5-V5 of FIG. 9A.

Fig. 10 is a schematic view showing a state in which the flange and the second exterior member are hermetically welded in a part of the range in the circumferential direction of the opening from the state of fig. 6.

Fig. 11 is a schematic view showing a state in which the electrolyte solution is injected into the housing space from the state of fig. 10, and the flange and the second exterior member are hermetically welded in a non-welded range in the circumferential direction of the opening.

Fig. 12 is a schematic view showing a state in which gas is discharged to the outside of the exterior cover from the opening hole in the vicinity of one side of the convex portion in the state of fig. 11.

Fig. 13 is a schematic view showing a state in which a welded portion is formed between the unsealing hole from which gas is discharged and the convex portion, from the state of fig. 11.

Fig. 14 is a schematic view showing a state where an opening hole different from the opening hole from which the gas is discharged in fig. 12 is formed in the vicinity of the other side of the convex portion from the state of fig. 13.

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. 15.

Fig. 17 is a sectional view schematically showing the convex portion and its vicinity in the state where the internal pressure of the exterior cover portion is lower than the external pressure of the exterior cover portion in the first embodiment.

Fig. 18 is a sectional view schematically showing the convex portion and the vicinity thereof in the second embodiment in a state where the internal pressure of the exterior cover is lower than the external pressure of the exterior cover.

Fig. 19 is a schematic diagram showing a system used for verification of the reduced pressure state of the storage space when the secondary battery is manufactured by the manufacturing method of the first embodiment.

Fig. 20 is a schematic view showing the measurement result of the temporal change in the degree of decompression of the storage space of the subject in the verification using the system of fig. 19.

Detailed Description

Hereinafter, an embodiment will be described with reference to fig. 1 to 20.

(first embodiment)

Fig. 1 shows an example of a secondary battery 1 manufactured by the manufacturing method of the first embodiment. The secondary battery 1 is, for example, a nonaqueous electrolyte battery. As shown in fig. 1, the secondary battery 1 includes an exterior package portion 3. The outer cover 3 is formed of a first outer jacket material 5 and a second outer jacket material 6. The

outer jacket members

5 and 6 are each formed of stainless steel. The first outer jacket material 5 is formed in a bottomed tubular shape. In the present embodiment, the first outer jacket material 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 outer jacket material 5, the bottom wall 7 and the side walls 8A to 8D define a housing space 11. The electrode group 10 is housed in the housing space 11.

Fig. 2 shows the first outer jacket material 5, the second outer jacket material 6, and the electrode group 10 in an exploded state. As shown in fig. 2, the housing space 11 has an opening 12 on the side opposite to the bottom wall 7. Here, in the secondary battery 1, a longitudinal direction (a direction indicated by an arrow X1 and an arrow X2), a lateral direction (a direction indicated by an arrow Y1 and an arrow Y2) perpendicular or substantially perpendicular to the longitudinal direction, and a thickness direction (a direction indicated by an arrow Z1 and an arrow Z2) perpendicular or substantially perpendicular to the longitudinal direction and the lateral direction are defined. In the secondary battery 1, the

side walls

8A, 8B are disposed apart from each other in the longitudinal direction with the housing space 11 therebetween, and the

side walls

8C, 8D are disposed apart from each other in the lateral direction with the housing space 11 therebetween. The side walls 8A to 8D extend in the thickness direction from the bottom wall 7 toward the opening 12, and the storage space 11 opens toward one side (arrow Z2 side) in the thickness direction in the opening 12.

In the first outer jacket material 5, a flange 13 is provided at a portion on the opposite side of the bottom wall 7. The flange 13 protrudes outward, i.e., away from the opening 12, with respect to the side walls 8A to 8D. The flange 13 defines an 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, for example, a substantially rectangular plate member. The second exterior member 6 is disposed to face the flange 13, and faces the flange 13 from the side of the opening 12. In the present embodiment, the second exterior member 6 protrudes outward from the side walls 8A to 8D, that is, 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. The second exterior member 6 is disposed in a state where 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 disposing the second outer jacket material 6 as described above, the opening 12 of the housing space 11 is closed by the second outer jacket material 6.

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

side walls

8A, 8B and the distance between the

side walls

8C, 8D. Therefore, in the secondary battery 1, the dimension in the thickness direction is much smaller than the dimension in the longitudinal direction and the dimension in the lateral 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 the dimension in the vertical direction is smaller than the dimension in the lateral direction in the secondary battery 1. The thickness of the first outer jacket material 5 is 0.02mm or more and 0.3mm or less in the bottom wall 7, the side walls 8A to 8D, and the flange 13, respectively. The second sheet-like casing member 6 has a thickness of 0.02mm to 0.3 mm.

Fig. 3 is a diagram illustrating the structure 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. Positive electrode 21 includes positive electrode current collector foil 21A serving as a positive electrode current collector, and positive electrode active material-containing layer 21B supported on the surface of positive electrode current collector foil 21A. 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. Positive electrode current collector foil 21A is coated with a slurry containing a positive electrode active material, a binder, and a conductive agent. The positive electrode active material is not limited to these, and examples thereof include oxides, sulfides, and polymers capable of inserting and extracting lithium. In addition, from the viewpoint of obtaining a high positive electrode potential, the positive electrode active material preferably uses a lithium manganese composite oxide, a lithium nickel composite oxide, a lithium cobalt composite oxide, lithium iron phosphate, or the like.

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 carried on the surface of the negative electrode current collector foil 22A. 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. Negative electrode current collector foil 12A is coated with a slurry containing a negative electrode active material, a binder, and a conductive agent. The negative electrode active material is not particularly limited, and examples thereof include a metal oxide, a metal sulfide, a metal nitride, a carbon material, and the like, which can intercalate and deintercalate lithium ions. As the negative electrode active material, a material having a lithium ion insertion/extraction potential of 0.4V or more with respect to the metallic lithium potential, that is, a material having a lithium ion insertion/extraction potential of 0.4V (vs⁺/Li) or more. By using a negative electrode active material having such a lithium ion intercalation/deintercalation potential, an alloy reaction between aluminum or an aluminum alloy and lithium can be suppressed, and therefore aluminum and an aluminum alloy can be used for the constituent members related to negative electrode current collector foil 22A and negative electrode 22. The insertion and extraction potential as lithium ions was 0.4V(vs.Li⁺Li), for example, a lithium titanium composite oxide such as titanium oxide or lithium titanate, a tungsten oxide, an amorphous tin oxide, a niobium-titanium composite oxide, a tin silicon oxide, or the like can be cited, and the lithium titanium composite oxide is particularly preferably used as the negative electrode active material. When a carbon material that intercalates and deintercalates lithium ions is used as the negative electrode active material, a copper foil is preferably used for the negative electrode current collector foil 22A. Li has an insertion and extraction potential of 0V (vs. li) for lithium ions in the carbon material used as the negative electrode active material⁺/Li) or so.

The aluminum alloy used for positive electrode current collector foil 21A and negative electrode current collector foil 22A preferably contains 1 or 2 or more elements selected from Mg, Ti, Zn, Mn, Fe, Cu, and Si. The purity of aluminum and aluminum alloys can be 98 wt% or more, preferably 99.99 wt% or more. In addition, pure aluminum having a purity of 100% can be used as a material of the positive electrode current collector and/or the negative electrode current collector. The content of the transition metal such as nickel or chromium in aluminum or an aluminum alloy is preferably 100 ppm by weight or less (including 0 ppm by weight).

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

The

separators

23 and 25 are each formed of an electrically insulating material, and electrically insulate the positive electrode 21 and the negative electrode 22 from each other. 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 formed integrally with one of the positive electrode 21 and the negative electrode 22. The

separators

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

separators

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

separators

23 and 25 include oxides (e.g., alumina, silica, magnesia, phosphorus oxide, calcium oxide, iron oxide, and titanium oxide), nitrides (e.g., boron nitride, aluminum nitride, silicon nitride, and 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 in a flat shape around the winding axis B with the

separators

23 and 25 interposed between the positive electrode active material containing layer 21B and the negative electrode active material containing layer 22B, respectively. At this time, for example, the cathode 21, the separator 23, the anode 22, and the separator 25 are wound in a state of being stacked in this order. In electrode group 10, positive current collecting tab 21D of positive current collector foil 21A protrudes toward one side in the direction along winding axis B with respect to negative electrode 22 and

separators

23 and 25. Negative current collecting tab 22D of negative current collecting foil 22A projects toward the opposite side from the side from which positive current collecting tab 21D projects in the direction along winding axis B with respect to positive electrode 21 and

separators

23 and 25. The electrode group 10 is disposed in a state where the winding axis 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 electrolyte (not shown) in the housing space 11. As the electrolytic solution, a nonaqueous electrolytic solution is used, and for example, a nonaqueous electrolytic solution prepared by dissolving an electrolyte in an organic solvent is used. In this case, as the electrolyte dissolved in the organic solvent, lithium perchlorate (LiClO) can be mentioned₄) Lithium hexafluorophosphate (LiPF)₆) Lithium tetrafluoroborate (LiBF)₄) Lithium hexafluoroarsenate (LiAsF)₆) Lithium trifluoromethanesulfonate (LiCF)₃SO₃) And bis (trifluoromethyl)Lithium phenylsulfonylimide [ LiN (CF)₃SO₂)₂]Lithium salts and mixtures thereof. Examples of the organic solvent include cyclic carbonates such as Propylene Carbonate (PC), Ethylene Carbonate (EC), and vinylene carbonate; chain carbonates such as diethyl carbonate (DEC), dimethyl carbonate (DMC), and ethyl methyl carbonate (MEC); cyclic ethers such as Tetrahydrofuran (THF), 2-methyltetrahydrofuran (2MeTHF), and Dioxolane (DOX); chain ethers such as Dimethoxyethane (DME) and Diethoxyethane (DEE); gamma-butyrolactone (GBL), Acetonitrile (AN), and Sulfolane (SL). These organic solvents are used alone or as a mixed solvent.

In one embodiment, a gel-like nonaqueous electrolyte obtained by compounding a nonaqueous electrolytic solution with a polymer material is used as the electrolytic solution. In this case, the above-mentioned electrolyte and organic solvent are used. Examples of the polymer material include polyvinylidene fluoride (PVdF), Polyacrylonitrile (PAN), and polyethylene oxide (PEO).

In one embodiment, a solid electrolyte such as a polymer solid electrolyte or an inorganic solid electrolyte is provided as the nonaqueous electrolyte instead of the electrolytic solution. In this case, the

separators

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

separators

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

As shown in fig. 1 and 2, an inclined surface 26 is provided on the outer surface of the first outer jacket material 5 between the bottom wall 7 and the side wall 8C. Further, an inclined surface 27 is provided on the outer surface of the first outer jacket material 5 between the bottom wall 7 and the side wall 8D. In the first outer jacket material 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. The

terminals

31 and 32 are each formed of a conductive material, for example, any one of aluminum, copper, and stainless steel.

Fig. 4 shows a configuration in which the positive electrode terminal 31 (negative electrode terminal 32) of the electrode group 10 is electrically connected. As shown in fig. 4, the positive electrode current collecting tabs 21D of the electrode group 10 are bundled by welding such as ultrasonic welding, and the bundle of the positive electrode current collecting tabs 21D is connected to the positive electrode support lead 35 by welding such as ultrasonic welding. The positive electrode support 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. The positive terminal lead 37 is connected to the positive terminal 31. The positive electrode support lead 35, the positive electrode lead 36, and the positive electrode terminal lead 37 are each formed of a conductive material. Therefore, the positive electrode collector tab 21D is electrically connected to the positive electrode terminal 31 via the positive electrode support lead 35, the positive electrode lead 36, and the positive electrode terminal lead 37. The positive electrode collector tab 21D, the positive electrode support lead 35, the positive electrode lead 36, the positive electrode terminal lead 37, and the positive electrode terminal 31 are electrically insulated from the

outer jacket materials

5 and 6, respectively.

Similarly, the negative electrode current collecting tabs 22D of the electrode group 10 are bundled by welding such as ultrasonic welding, and the bundle of the negative electrode current collecting tabs 22D is connected to the negative electrode support lead 41 by welding such as ultrasonic welding. The negative electrode support 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. The negative electrode terminal lead 43 is connected to the negative electrode terminal 32. The negative electrode support lead 41, the negative electrode lead 42, and the negative electrode terminal lead 43 are each formed of a conductive material. Therefore, the negative electrode collector tab 22D is electrically connected to the negative electrode terminal 32 via the negative electrode support lead 41, the negative electrode lead 42, and the negative electrode terminal lead 43. The negative current collecting tab 22D, the negative support lead 41, the negative lead 42, the negative terminal lead 43, and the negative terminal 32 are electrically insulated from the

outer members

5 and 6, respectively.

Fig. 5 shows secondary battery 1 as viewed from the side of first outer jacket material 5 where bottom wall 7 is located in the thickness direction. As shown in fig. 5, the secondary battery 1 is formed with welding portions 45 to 48 for hermetically welding the flange 13 and the second exterior member 6. The welding portions 45 to 48 are provided outside the edge 15 of the opening 12, i.e., on the side away from the opening 12 with respect to the edge 15. In the present embodiment, the welding portion 45 is formed in a protruding portion from the side wall 8A toward the outside in the longitudinal direction in the flange 13 and the second exterior member 6, and extends in the lateral direction. The welding portion 46 is formed in a protruding portion from the side wall 8B to the outside in the longitudinal direction in the flange 13 and the second external packaging member 6, and extends in the lateral direction. In addition, the welding portion 47 is formed in a protruding portion from the side wall 8C to the outside in the lateral direction in the flange 13 and the second exterior member 6, and extends in the longitudinal direction. The welding portion 48 is formed in a protruding portion laterally outward from the side wall 8D in the flange 13 and the second external packaging member 6, and extends in the longitudinal direction. In addition, in the drawings 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 welding portion 46 is continuous with the welding portion 47, and the other end is continuous with the welding portion 48. Therefore, the flange 13 and the second outer cover 6 are hermetically welded over the entire circumference in the circumferential direction of the opening 12 by the welding portions 45 to 48. Therefore, the housing space 11 for housing the electrode group 10 is sealed from the outside of the exterior cover 3 by the welding 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 or the like, and the airtightness between the flange 13 and the second exterior member 6 is high.

Next, a method for manufacturing the secondary battery 1 in the present embodiment will be described. In manufacturing the secondary battery 1, the first outer jacket material 5 is formed of stainless steel. At this time, the first outer jacket material 5 is formed in a state in which the storage space 11 is defined by the bottom wall 7 and the side walls 8A to 8D and the opening 12 is provided on the side of the storage space 11 opposite to the bottom wall 7. The first outer jacket material 5 is formed to have a thickness of 0.02mm or more and 0.3mm or less. In forming the first outer jacket material 5, a flange 13 is formed in the first outer jacket material 5 at a position on the opposite side of the bottom wall 7. At this time, the flange 13 is formed in a state in which the flange 13 protrudes to a 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.

In the manufacture of the secondary battery 1, the second exterior member 6 is formed of stainless steel. In a certain embodiment, the second exterior member 6 is formed in a plate shape. The second outer covering member 6 is formed to have a thickness of 0.02mm to 0.3 mm. In the manufacture of the secondary battery 1, an electrode group 10 including a positive electrode 21 and a negative electrode 22 is formed. In one 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

outer package members

5 and 6 and the electrode group 10 are formed, the electrode group 10 is disposed in the housing 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 disposed in the housing space 11 in a state where the winding axis B is parallel or substantially parallel to the lateral direction of the secondary battery 1.

Then, the positive electrode collector tab 21D of the electrode group 10 is electrically connected to the positive electrode terminal 31 via the positive electrode support lead 35, the positive electrode lead 36, and the positive electrode terminal lead 37. Similarly, the negative electrode collector tab 22D of the electrode group 10 is electrically connected to the negative electrode terminal 32 via the negative electrode support lead 41, the negative electrode lead 42, and the negative electrode terminal lead 43. Further, an insulating member is provided to electrically insulate the positive electrode collector tab 21D, the positive electrode support lead 35, the positive electrode lead 36, the positive electrode terminal lead 37, and the positive electrode terminal 31 from the

outer jacket members

5 and 6, respectively. Similarly, an insulating member is provided to electrically insulate the negative electrode current collecting tab 22D, the negative electrode support lead 41, the negative electrode lead 42, the negative electrode terminal lead 43, and the negative electrode terminal 32 from the

outer jacket members

5 and 6, respectively.

Then, the second exterior member 6 is disposed to face the flange 13 in a state where the electrode group 10 is disposed in the housing space 11. Fig. 6 shows a state in which the second exterior member 6 is disposed to face the flange 13 at the time of manufacturing the secondary battery 1. Fig. 6 shows the first outer jacket material 5 as viewed from the side where the bottom wall 7 is located. As shown in fig. 6, by disposing the second exterior material 6 so as to face the flange 13, the second exterior material 6 protrudes to the side away from the opening 12 with respect to the side walls 8A to 8D over the entire circumference of the opening 12 in the circumferential direction. In the region outside the edge 15 of the opening 12, the second exterior member 6 is disposed so as to face the flange 13 over the entire circumference of the opening 12 in the circumferential direction. In the present embodiment, the second exterior member 6 is opposed to the flange 13 in a state where the thickness direction of the plate-shaped second exterior member 6 is aligned or substantially aligned with the thickness direction of the secondary battery 1. By disposing the second outer jacket material 6 as described above, the opening 12 of the storage space 11 is closed by the second outer jacket material 6.

In addition, in the manufacture of the secondary battery 1, the opening hole (first opening hole) 51A is formed in the flange 13 in the formation of the flange 13, or the opening hole 51A is formed in the second exterior packaging member 6 in the formation of the second exterior packaging member 6. Therefore, in manufacturing the secondary battery 1, the 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 φ a. The diameter φ a is, for example, about 1 mm. In the manufacture of the secondary battery 1, the

protrusions

52A and 52B are formed on the flange 13 in the formation of the flange 13, or the

protrusions

52A and 52B are formed on the second outer covering member 6 in the formation of the second outer covering member 6. Therefore, in manufacturing the secondary battery 1, the

convex portions

52A and 52B are formed on one of the flange 13 and the second exterior member 6, respectively. At this time, the convex portion (first convex portion) 52A is formed in the vicinity of the opening hole 51A. In addition, the

convex portions

52A, 52B are formed at positions apart from each other.

The opening hole 51A and the protruding

portions

52A and 52B are disposed outside the edge 15 of the opening 12 in a state where the second outer package member 6 is disposed to face the flange 13. In a state where the second exterior member 6 is disposed to face the flange 13, the

protrusions

52A and 52B protrude toward the other of the flange 13 and the second exterior member 6, that is, toward the flange 13 and the second exterior member where the

protrusions

52A and 52B are not provided. In the present embodiment, the second exterior member 6 is opposed to the flange 13 in a state where the protruding direction of the protruding

portions

52A, 52B coincides or substantially coincides with the thickness direction of the secondary battery 1. In one embodiment, for example, the second outer package member 6 is opposed to the flange 13 with the

projections

52A and 52B provided on the flange 13 and the

projections

52A and 52B projecting toward the second outer package member 6, respectively.

In addition, in an embodiment, by disposing the second outer covering member 6 so as to face the flange 13, the opening hole 51A and the

convex portions

52A and 52B are located at the protruding portion outward in the longitudinal direction from the side wall 8A in the flange 13 or the second outer covering member 6. At this time, the convex portion (first convex portion) 52A is located at an end portion on a side close to the side wall 8C in the lateral direction, and the convex portion (second convex portion) 52B is located at an end portion on a side close to the side wall 8D in the lateral direction. Therefore, in a state where the second exterior member 6 is disposed to face the flange 13, the convex portion 52B is located at a position away from the opening hole 51A and the convex portion 52A in the lateral direction of the secondary battery 1. In the drawings of the secondary battery 1 such as fig. 6 viewed from one side in the thickness direction, the

convex portions

52A and 52B are illustrated as being blackened.

In a state where the second exterior packaging member 6 is disposed to face the flange 13, the opening hole (first opening hole) 51A is disposed apart from the edge 15 of the opening 12 by a distance D1A. The distance D1a is, for example, about 20 mm. In a state where the second outer package member 6 is disposed to face the flange 13, the opening hole 51A is disposed outside the projection (first projection) 52A, i.e., on the side farther from the opening 12. The convex portion 52A is disposed in the vicinity of the opening hole 51A. At this time, the distance D2A from the opening hole 51A to the projection 52A is 6mm or less. In a state where the second exterior material 6 is disposed to face the flange 13, the convex portion 52A is disposed at a distance D3a from the edge 15 of the opening 12, and the convex portion 52B is disposed at a distance D3B from the edge 15 of the opening 12. In the present embodiment, the distances D3a and D3b are the same or substantially the same size, and the distances D3a and D3b are, for example, about 4mm, respectively.

Here, the

convex portions

52A and 52B will be described. Fig. 7A to 7C show a first embodiment regarding the configuration of the convex portion 52A (52B) and the vicinity thereof. Fig. 7A to 7C show the convex portion 52A (52B) and its vicinity in the state of fig. 6 at the time of manufacture. In addition, FIG. 7B shows the section V1-V1 of FIG. 7A, and FIG. 7C shows the section V2-V2 of FIG. 7A. In the state of fig. 6, the internal pressure inside outer package portion 3 is the same or substantially the same as the external pressure outside outer package portion 3. In the present embodiment, the

projections

52A and 52B are each formed in a tunnel ceiling shape (tunnel vacuum form). Therefore, the

projections

52A and 52B define a longitudinal direction (tunnel axial direction), a width direction perpendicular or substantially perpendicular to the longitudinal direction, and a projecting direction perpendicular or substantially perpendicular to the longitudinal direction and perpendicular or substantially perpendicular to the width direction, respectively. In the present embodiment, the longitudinal direction of each of the

convex portions

52A, 52B is aligned or substantially aligned with the longitudinal direction of the secondary battery 1, and the width direction of each of the

convex portions

52A, 52B is aligned or substantially aligned with the lateral direction of the secondary battery 1. Here, in fig. 7B, the convex portion 52A (52B) is shown as a cross section perpendicular or substantially perpendicular to the longitudinal direction, and in fig. 7C, the convex portion 52A (52B) is shown as a cross section parallel or substantially parallel to the longitudinal direction and perpendicular or substantially perpendicular to the width direction.

In the

convex portions

52A and 52B, the cross-sectional shapes perpendicular or substantially perpendicular to the longitudinal direction are made uniform or substantially uniform over the entire length in the longitudinal direction. In the present embodiment, the

projections

52A and 52B are formed in a substantially U-shape or a substantially semicircular arc shape in cross section perpendicular or substantially perpendicular to the longitudinal direction. The

projections

52A and 52B are formed with 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, and the dimensions D4a and D4b are, for example, about 10mm, respectively. The

projections

52A and 52B are each formed with a width (corresponding one of W1a and W1B) in the width direction. The widths W1a and W1b are the same or substantially the same size, and the widths W1a and W1b are, for example, about 1.2mm, respectively. The

projections

52A and 52B are formed to have projection dimensions (corresponding to one of P1a and P1B) to the projection ends, respectively. The projecting dimensions P1a and P1b are the same or substantially the same size, and the projecting dimensions P1a and P1b are, for example, about 0.4mm, respectively.

In addition, in the second embodiment shown in fig. 8A and 8B, two (a plurality of) convex portions 52A1, 52A2 are formed as the convex portion 52A, and two (a plurality of) convex portions 52B1, 52B2 are formed as the convex portion 52B. Here, fig. 8A and 8B show the configuration of the projections 52a1, 52a2(52B1, 52B2) and their vicinity in the state of fig. 6 at the time of manufacture. In addition, FIG. 8B shows the section V3-V3 of FIG. 8A. In the present embodiment, the projections 52A1, 52A2, 52B1, 52B2 are formed in a tunnel ceiling shape in the same manner as the

projections

52A, 52B of the first embodiment, respectively. Therefore, the projections 52a1, 52a2, 52B1, and 52B2 define the longitudinal direction, the width direction, and the projecting direction, respectively. The longitudinal direction of each of the convex portions 52a1, 52a2, 52B1, and 52B2 is aligned or substantially aligned with the longitudinal direction of the secondary battery 1, and the width direction of each of the convex portions 52a1, 52a2, 52B1, and 52B2 is aligned or substantially aligned with the lateral direction of the secondary battery 1. In the projections 52a1, 52a2, 52B1, and 52B2, the cross-sectional shapes perpendicular or substantially perpendicular to the longitudinal direction are made uniform or substantially uniform over the entire length in the longitudinal direction. In the present embodiment, the projections 52a1, 52a2, 52B1, 52B2 are formed to have a substantially U-shaped or a substantially semicircular arc-shaped cross section perpendicular or substantially perpendicular to the longitudinal direction. In fig. 8B, the convex portion 52a1 and the convex portion 52a2(52B1 and 52B2) are each shown as a cross section perpendicular or substantially perpendicular to the longitudinal direction.

The convex portions (first convex portions) 52a1, 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 52a 2. The convex portions 52a1 and 52a2 are formed to extend parallel or substantially parallel to each other. The convex portions 52a1 and 52a2 are formed in a state of being aligned in a specific direction. In the present embodiment, the specific direction in which the convex portions 52a1, 52a2 are arranged is made to coincide or substantially coincide with the lateral direction of the secondary battery 1, and is perpendicular or substantially perpendicular with respect to the longitudinal direction of each of the convex portions 52a1, 52a 2. The convex portions 52a1, 52a2 are formed in the same or substantially the same range with respect to each other in the longitudinal direction of the secondary battery 1. Similarly, the convex portions (second convex portions) 52B1, 52B2 are formed in a state of being close to each other. That is, the convex portion 52B1 is formed in the vicinity of the convex portion 52B 2. The convex portions 52B1 and 52B2 are formed to extend parallel or substantially parallel to each other. The convex portions 52B1 and 52B2 are formed in a state of being aligned in a specific direction. In the present embodiment, the specific direction in which the convex portions 52B1, 52B2 are arranged is made to coincide or substantially coincide with the lateral direction of the secondary battery 1, and is perpendicular or substantially perpendicular with respect to the longitudinal direction of each of the convex portions 52B1, 52B 2. The convex portions 52B1 and 52B2 are formed in the same or substantially the same range with respect to each other in the longitudinal direction of the secondary battery 1.

The projections 52a1, 52a2, 52B1, and 52B2 are each formed with a dimension (corresponding to one of D5a, D6a, D5B, and D6B) in the longitudinal direction. The dimensions D5a, D6a, D5b, and D6b are the same or substantially the same size, and the dimensions D5a, D6a, D5b, and D6b are, for example, about 10mm, respectively. The convex portions 52a1, 52a2, 52B1, and 52B2 are each formed with a width (corresponding one of W2a, W3a, W2B, and W3B) in the width direction. Widths W2a, W3a, W2b, and W3b are the same or substantially the same size as each other, and widths W2a, W3a, W2b, and W3b are, for example, about 1.2mm, respectively. Further, the convex portions 52a1, 52a2, 52B1, 52B2 are formed to the projecting ends with a projecting dimension (corresponding one of P2a, P3a, P2B, P3B), respectively. The projecting dimensions P2a, P3a, P2b, and P3b are the same or substantially the same size, and the projecting dimensions P2a, P3a, P2b, and P3b are, for example, about 0.6mm, respectively. The convex portions 52a1, 52a2 are formed at a distance W4a from each other in a predetermined direction in which the convex portions 52a1, 52a2 are aligned, in the lateral direction of the secondary battery 1 in this embodiment. Similarly, the convex portions 52B1, 52B2 are formed at a separation distance W4B with respect to each other in a predetermined direction in which the convex portions 52B1, 52B2 are aligned, 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 as each other, and the widths W4a and W4b are, for example, about 0.6mm, respectively.

In addition, in the third embodiment shown in fig. 9A to 9C, the

convex portions

52A, 52B are respectively formed in a dome shape. Here, fig. 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. FIG. 9B shows the section V4-V4 of FIG. 9A, and FIG. 9C shows the section V5-V5 of FIG. 9A. The cross section of fig. 9B and the cross section of fig. 9C are cross sections parallel or substantially parallel to the protruding direction of the convex portion 52A (52B), and are perpendicular or substantially perpendicular to each other. In the present embodiment, as described above, the

convex portions

52A and 52B are formed in dome shapes. Therefore, as shown in fig. 9B, the cross-sectional shape of each of the

projections

52A and 52B perpendicular or substantially perpendicular to the longitudinal direction of the secondary battery 1 is formed in a substantially U-shape or a substantially semicircular arc shape. As shown in fig. 9C, the

projections

52A and 52B are formed to have a substantially U-shaped or a substantially semicircular arc shape in cross section perpendicular or substantially perpendicular to the lateral direction of the secondary battery 1. That is, the

projections

52A and 52B are formed to have a U-shaped or substantially semicircular arc-shaped cross section in any cross section parallel or substantially parallel to the projecting direction.

In the present embodiment, when the second exterior material 6 is disposed so as to face the flange 13 as described above, the flange 13 and the second exterior material 6 are hermetically welded in a part of the range of the opening 12 in the circumferential direction, as shown in fig. 10. Thus, the welding portions 46 to 48 are formed before the electrolyte is injected into the housing space 11. At this time, the electric resistance seam welding is performed to form the welding portions 46 to 48. Before the electrolyte is injected, the flange 13 and the second exterior member 6 are not welded to each other in a part of the circumferential direction of the opening 12. Therefore, in the state of fig. 10, in the range where the side wall 8A extends in the circumferential direction of the opening 12, no welded portion is formed. In the state of fig. 10, the electrolyte solution is injected into the housing space 11 from the flange 13 and the portion of the second exterior member 6 not welded. At this time, the electrolyte is injected from a certain portion in the range where the side wall 8A extends in the circumferential direction of the opening 12. The electrolyte is injected into the housing space 11 through the gap between the flange 13 and the second exterior member 6.

After the electrolyte solution is injected, as shown in fig. 11, the flange 13 and the second exterior material 6 are hermetically welded by resistance seam welding in the unwelded range in the circumferential direction of the opening. Thereby, the welded portion 50 is formed. In the state of fig. 11, a weld portion 50 is formed in a protruding portion of the flange 13 and the second exterior member 6 outward in the longitudinal direction from the side wall 8A. The welding portion 50 is formed in a state where one end is continuous with the welding portion 47 and the other end is continuous with the welding portion 48. The welded portion 50 is formed outside the opening hole 51A and the

projections

52A and 52B, i.e., on the side away from the opening 12. By forming the welding portion 50 as described above, the flange 13 and the second exterior member 6 are hermetically welded over the entire circumference in the circumferential direction of the opening 12 by the welding portions 46 to 48, 50. That is, the welding portions (first welding portions) 46 to 48, 50 for airtightly welding the flange 13 and the second exterior member 6 are formed over the entire circumference of the opening 12 in the circumferential direction. By forming the welded portion 50, the inside (the housing space 11) of the exterior cover 3 is in a state of communicating with the outside of the exterior cover 3 only through the opening hole 51A. In a view of the secondary battery 1 such as fig. 11 viewed from one side in the thickness direction, the welded portion 50 is indicated by a broken line.

In the state of fig. 11 where the welding portion 50 is formed, the inside of the outer package portion 3 communicates with the outside through the opening hole 51A. Therefore, in the state of fig. 11, the internal pressure inside outer package portion 3 (the pressure in storage space 11) is the same or substantially the same as the external pressure outside outer package portion 3. In the state of fig. 11, a gap is formed between the flange 13 and the second outer cover member 6 over the entire or most part of the region inside the welding portions 46 to 48, 50 and outside the edge 15 of the opening 12. At this time, in the region inside the welding portions 46 to 48, 50 and outside the edge 15 of the opening 12, for example, in the region other than the protruding ends of the protruding

portions

52A, 52B, the flange 13 has a gap with the second exterior packaging member 6 and is not in close contact with the second exterior packaging member 6.

In the embodiment using the solid electrolyte interposed between the positive electrode 21 and the negative electrode 22 instead of the electrolytic solution, the operation of injecting the electrolytic solution may not be necessary. In this case, the welds 46 to 48 may be formed after the welds 50 are formed. However, in the present embodiment, the flange 13 and the second exterior member 6 are also hermetically welded over the entire circumference in the circumferential direction of the opening 12 by the welding portions (first welding portions) 46 to 48, 50.

When the welded portion 50 is formed, the gas in the housing space 11 is discharged from the opening hole 51A to the outside of the outer package portion 3. That is, the gas in the storage space 11 is discharged from the unsealing position (first unsealing 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. At this time, as shown in fig. 12, a suction pad 55 is attached to the outer surface of the outer package 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. Further, a valve 61 and a vacuum regulator 62 are disposed in a suction path between the pump 57 and the suction pad 55. When the gas is discharged from the opening hole 51A, the pump 57 is driven and the valve 61 is opened after the suction pad 55 is attached to the exterior packaging portion 3. Thus, the gas flows from the housing space 11 to the opening hole 51A through the gap between the flange 13 and the second outer covering member 6 in the outer covering portion 3. Then, the gas is sucked from the opening hole 51A into the suction tube 56, passes through the inside of the suction tube 56, and flows toward the pump 57. Thereby, the gas is discharged from the opening hole 51A to the outside of the outer package portion 3. The discharge from the easy-open hole 51A is performed in an environment having a dew point temperature of-50 ℃.

Then, when the gas is discharged from the opening hole 51A to the outside of the outer package portion 3 and the internal pressure inside the outer package portion 3 such as the pressure of the housing space 11 is reduced to some extent, the flange 13 and the second outer package member 6 are hermetically welded between the opening hole (first opening position) 51A and the projection 52A as shown in fig. 13. That is, the welded portion 53A is formed between the opening hole 51A and the convex portion 52A. The welded portion 53A is formed in a state of being inclined with respect to the longitudinal direction and the lateral direction of the secondary battery 1. The welded portion 53A is formed in a state where 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 path of the gas is cut between the opening hole (first opening position) 51A and the convex portion (first convex portion) 52A. The welded portions 53A are formed by, for example, resistance seam welding, similarly to the welded portions 46 to 48, 50. In a view of the secondary battery 1 such as fig. 13 viewed from one side in the thickness direction, the welded portion 53A is indicated by a broken line.

The flange 13 and the second exterior material 6 are hermetically welded at a portion inside the opening hole 51A by forming the welding portion 53A, and the flange 13 and the second exterior material 6 are hermetically welded over the entire circumference of the opening 12 in the circumferential direction by the welding portions 46 to 48, 50, and 53A. Thereby, the housing space 11 housing the electrode group 10 is sealed from the outside of the exterior package portion 3.

When the welding part 53A is formed, the flange 13 and the second outer package member 6 are cut to the outside of the welding parts 46 to 48. Then, the secondary battery 1 is charged (initially charged) and aged. Thereby, gas is generated in the housing space 11 housing the electrode group 10. When the aging is performed as described above, it is necessary to discharge the gas generated by the aging to the outside of the exterior package portion 3. The aging temperature is preferably in the range of 70 ℃ to 90 ℃.

Therefore, as shown in fig. 14, the 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 close to the opening 12. The opening hole 51B is formed outside the projection 52B, i.e., on the side farther from the opening 12. That is, the open 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 φ B. The diameter Φ B of the opening hole 51B is the same as or substantially the same as the diameter Φ a of the opening hole 51A, and is, for example, about 1 mm. In addition, an open hole (second open hole) 51B is formed at a position separated by a distance D1B from the edge 15 of the opening 12. The distance D1b is the same or substantially the same as the distance D1a, and is, for example, about 20 mm. The operator forms the opening hole 51B in the vicinity of the convex portion 52B. At this time, the opening hole 51B is formed in a state where the distance D2B from the projection 52B to the opening hole 51B is 6mm or less. The opening hole 51B is formed at a position distant from the opening hole 51A and the protruding portion 52A in the lateral direction of the secondary battery 1. In the formation of the opening hole 51B, first, through holes are formed in both the flange 13 and the second external packaging member 6. Then, one of the two through holes is hermetically sealed. Thereby, one of the two through holes which is not sealed is used as the open hole 51B.

When the opening hole 51B is formed, the gas in the housing space 11 is discharged from the opening hole 51B to the outside of the package portion 3. That is, the gas in the storage space 11 is discharged from the unsealing position (second unsealing 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. At this time, similarly to the discharge of the gas from the unsealing hole (first unsealing position) 51A, the gas is discharged from the unsealing hole 51B using the suction pad 55, the suction pipe 56, the pump 57, the valve 61, the vacuum regulator 62, and the like. At this time, the gas flows from the housing space 11 to the opening hole 51B through the gap between the flange 13 and the second outer covering member 6 in the outer covering portion 3. Then, the gas is sucked into the suction tube 56 from the opening hole 51B, passes through the inside of the suction tube 56, and flows toward the pump 57. Thereby, the gas is discharged from the opening hole 51B to the outside of the outer package portion 3. The discharge from the unsealing hole (second unsealing position) 51B is also performed in an environment having a dew point temperature of-50 ℃.

Then, when the gas is discharged from the opening hole 51B to the outside of the outer package portion 3 and the internal pressure inside the outer package portion 3 such as the pressure of the housing space 11 is reduced to some extent, the flange 13 and the second outer package member 6 are hermetically welded between the opening hole (second opening position) 51B and the projection 52B as shown in fig. 15. That is, the welded portion 53B is formed between the opening hole 51B and the convex portion 52B. The welded portion 53B is formed in a state of being inclined with respect to the longitudinal direction and the lateral direction of the secondary battery 1. The welded portion 53B is formed in a state where 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 path of the gas is cut between the opening hole (second opening position) 51B and the convex portion (second convex portion) 52B. The welded portions 53B are formed by, for example, resistance seam welding, similarly to the welded portions 46 to 48, 50, and 53B. In a view of the secondary battery 1 such as fig. 15 viewed from one side in the thickness direction, the welded portion 53B is indicated by a broken line.

The flange 13 and the second exterior member 6 are hermetically welded at a portion inside the opening holes 51A and 51B by forming the welding portion 53B, and the flange 13 and the second exterior member 6 are hermetically welded over the entire circumference in the circumferential direction of the opening 12 by the welding portions 46 to 48, 50, 53A, and 53B. Thereby, the housing space 11 housing the electrode group 10 is sealed again from the outside of the exterior package 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 outer cover 6 are hermetically welded to each other at positions inward of the

projections

52A and 52B, thereby forming a welded portion (second welded portion) 45. The welding 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 welded portion 45 is formed by resistance seam welding outside the edge 15 of the opening 12. The welding portion 45 is formed in a state where one end is continuous with the welding portion 47 and the other end is continuous with the welding portion 48. In the present embodiment, the welding portion 45 is formed in a protruding portion from the side wall 8A to the outside in the longitudinal direction in the flange 13 and the second exterior member 6, and extends in the lateral direction of the secondary battery 1. By forming the welded portion (second welded portion) 45, the path of the gas is cut 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) 52B.

Then, a portion outside the welded portion 50 is cut out of the flange 13 and the second exterior member 6. Thereby, as shown in fig. 5, the opening holes (opening positions) 51A and 51B and the

projections

52A and 52B are removed. Even if the portion outside the welded portion 50 is cut, the flange 13 and the second outer cover member 6 are hermetically welded over the entire circumference in the circumferential direction of the opening 12 by the welded portions 45 to 48. Therefore, even if the portion outside the welded portion 50 is cut, the housing space 11 in which the electrode group 10 is disposed is sealed from the outside of the exterior cover 3. As described above, the secondary battery 1 was manufactured.

In addition, in a certain embodiment, the welding portion 45 is not formed. In this case, the flange 13 and the second exterior member 6 are hermetically welded over the entire circumference in the circumferential direction of the opening 12 by the welding portions 46 to 48, 50, 53A, and 53B, and the housing space 11 is sealed from the outside. In addition, in the present embodiment, the

convex portions

52A, 52B and the

open holes

51A, 51B are provided in the manufactured secondary battery 1.

In another embodiment in which the welded portion 45 is not formed, during manufacturing, after the welded portion 53A is formed, a portion of the flange 13 and the second exterior member 6 on the outer side of the welded portion 53A is cut. Thereby, the opening hole 51A is removed, and the opening hole 51A is not provided in the manufactured secondary battery 1. Similarly, in another embodiment in which the welded portion 45 is not formed, at the time of manufacturing, after the welded portion 53B is formed, a portion outside the welded portion 53B is cut out of the flange 13 and the second external packaging member 6. Thereby, the opening hole 51B is removed, and the opening hole 51B is not provided in the manufactured secondary battery 1. In another embodiment in which the welded portion 45 is not formed, during manufacturing, a portion outside the welded portion 53A and a portion outside the welded portion 53B are cut, and both the

open holes

51A and 51B are not provided in the manufactured secondary battery 1.

As described above, in the manufacture of the secondary battery 1, the gas is discharged from the easy-open hole 51A and the gas is discharged from the easy-open hole 51B. When the gas is discharged to the outside of the outer package portion 3, the pressure of the housing space 11, that is, the internal pressure inside the outer package portion 3 decreases. This reduces the internal pressure inside outer package 3 as compared with the external pressure outside outer package 3. By the inner pressure being lower than the outer pressure, the flange 13 and the second exterior member 6 are in close contact with each other at a position away from the

protrusions

52A, 52B. However, in the present embodiment, the

convex portions

52A and 52B are provided on one of the flange 13 and the second external packaging member 6, and the flange 13 and the second external packaging member 6 are formed of stainless steel. Therefore, even in a state where the internal pressure is lower than the external pressure, the flange 13 has a gap with respect to the second outer package member 6 in the vicinity of the protruding end of the convex portion 52A, and does not come into close contact with the second outer package member 6. Similarly, even in a state where the internal pressure is lower than the external pressure, the flange 13 has a gap with respect to the second outer package member 6 in the vicinity of the protruding end of the convex portion 52B, and does not come into close contact with the second outer package member 6. At this time, the flange 13 abuts against the second exterior member 6 at the projecting ends of the

projections

52A and 52B.

Fig. 17 shows the convex portion 52A (52B) and its vicinity in the state where the internal pressure of the exterior cover 3 is lower than the external pressure of the exterior cover 3 in the configuration of the first embodiment described above. In fig. 17, the convex portion 52A (52B) is shown as a cross section perpendicular or substantially perpendicular 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 has a gap with respect to the second exterior member 6 in the vicinity of the projecting ends of the

respective projections

52A, 52B, and does not come into close contact with the second exterior member 6. In the third embodiment, as in the first embodiment, even if 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 projecting ends of the projecting

portions

52A and 52B, and does not come into close contact with 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 has a gap with respect to the second outer package member 6 in the vicinity of the projecting ends of the

convex portions

52A and 52B, regardless of the magnitude of the external pressure and the internal pressure, and does not come into close contact with the second outer package member 6. Therefore, even if the internal pressure is lower than the external pressure due to the suction from one of the opening holes (unsealing positions) 51A, 51B, it is ensured that the path of the gas is not cut in the vicinity of the projecting ends of the projecting

portions

52A, 52B. Thus, even when the internal pressure is lower than the external pressure during the manufacturing, the path of the gas from the storage space 11 to the unsealing holes (one corresponding to 51A, 51B) is not cut off, and the gas easily flows from the storage space 11 to the unsealing holes (one corresponding to 51A, 51B) through the vicinity of the protruding ends of the convex portions (one corresponding to 48A, 48B). Therefore, even if the internal pressure is lower than the external pressure, the gas reaches the opening hole (corresponding one of the opening holes 51A and 51B) and is appropriately discharged from the opening hole (corresponding one of the opening holes 51A and 51B). As described above, by appropriately discharging the gas from the easy-

open holes

51A and 51B at the time of manufacturing, substantially no gas remains in the housing space 11, which is the inside of the exterior cover 3, in the manufactured secondary battery 1. This can produce the secondary battery 1 having a low internal resistance and a long life.

Fig. 18 shows the convex portions 52a1, 52a2(52B1, 52B2) and the vicinity thereof in the state where the internal pressure of the exterior portion 3 is lower than the external pressure of the exterior portion 3 in the configuration of the second embodiment described above. In fig. 18, the projections 52a1, 52a2(52B1, 52B2) are shown in cross section perpendicular or substantially perpendicular to the longitudinal direction. As shown in fig. 18, in the second embodiment as well, even if the internal pressure is lower than the external pressure, the flange 13 has a gap with respect to the second exterior packaging member 6 in the vicinity of the projecting ends of the projections 52a1, 52a2, 52B1, 52B2 and does not come into close contact with the second exterior packaging member 6, as in the first and third embodiments. Therefore, as described above, even if the internal pressure is lower than the external pressure, the gas reaches the opening hole (corresponding one of the opening holes 51A and 51B) and is discharged from the opening hole (corresponding one of the opening holes 51A and 51B).

In addition, in the second embodiment, since the protrusions 52a1, 52a2 are close relative to each other, even if the inner pressure is lower than the outer pressure, the gap of the flange 13 relative to the second exterior packaging member 6 is maintained large between the protruding ends of the protrusions 52a1, 52a 2. Also, in the second embodiment, since the protrusions 52B1, 52B2 are close relative to each other, even if the inner pressure is lower than the outer pressure, the gap of the flange 13 relative to the second exterior packaging member 6 is maintained large between the protruding ends of the protrusions 52B1, 52B 2. Thus, in the second embodiment, in a state where the internal pressure is lower than the external pressure, the gas more easily flows from the storage space 11 to the unsealing holes (corresponding one of 51A and 51B) 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 52B 2. Therefore, in the second embodiment, the gas can be more effectively discharged from the opening hole (the corresponding one of the opening holes 51A and 51B) to the outside of the exterior packaging part 3.

(verification relating to embodiment)

Here, the operation and effect of the above-described embodiment were verified. Fig. 19 shows a system used in verification relating to the decompressed state of the housing space 11 in the manufacture of the secondary battery 1. As shown in fig. 19, in the verification, a subject 1' simulating the above-described secondary battery 1 is formed. In the subject 1 ', the outer package 3' is formed by the first outer package 5 'and the second outer package 6' made of stainless steel. In the first outer jacket material 5 ', the bottom wall 7 ' and the side walls 8 ' a to 8 ' D are formed and the housing space 11 ' is defined, as in the first outer jacket material 5 described above. The housing space 11 'is opened by the opening 12', similarly to the first outer jacket material 5. In the first outer jacket material 5 ', a flange 13 ' is formed, which defines an edge 15 ' of the opening 12 ' of the housing space 11 ', as in the first outer jacket material 5. The second exterior member 6' is formed in a plate shape, similarly to the second exterior member 6 described above. The second outer package member 6 'is disposed to face the flange 13', and the opening 12 'is closed by the second outer package member 6'. The first outer jacket material 5 'and the second outer jacket material 6' are each formed to have a thickness of 0.1 mm.

In the subject 1 ', the same welding portions 46 ' to 48 ', 50 ' as the above-described welding portions 46 to 48, 50 are formed by resistance seam welding, and the flange 13 ' and the second exterior member 6 ' are hermetically welded over the entire circumference in the circumferential direction of the opening 12 '. In the subject 1 ', the opening hole 51 ' a is formed in the flange 13 ' at the same position as the opening hole 51A described above. The opening hole 51 'a is formed inward of the welded portion 50'. The diameter Φ 'a of the opening hole 51' a is 1mm, and the distance D '1 a from the edge 15' of the opening 12 'to the opening hole 51' a is 20 mm. In the subject 1', the opening corresponding to the opening hole 51B, the convex portion corresponding to the convex portion 52B (including 52B1 and 52B2), and the weld portion corresponding to the

weld portions

45, 53A, and 53B are not formed.

In the verification, the gas in the housing space 11 ' is discharged from the opening hole 51 ' a to the outside of the exterior package portion 3 '. Further, the gas was discharged under an environment having a dew point temperature of-60 ℃. At this time, similarly to the discharge of gas at the time of manufacturing the secondary battery 1, the gas is discharged to the outside of the exterior package portion 3' using the suction pad 55, the suction tube 56, the pump 57, the valve 61, and the vacuum regulator 62. As the suction pad 55, a flat pad manufactured by MISUMI, model ZP2-B10MTF was used. As the pump 57, a pump 57 having a model number DA41D manufactured by ULVAC corporation, an effective exhaust velocity of 40L/min (0.67L/sec), an arrival pressure of-98 kPa, and a set pressure of the vacuum regulator 62 of-100 kPa was used. In the verification, the fitting 65 is attached to the bottom wall 7 'of the first outer package 5', and the fitting 65 is connected to the pressure sensor 67 via the pipe 66. In a state where the gas is discharged from the easy-open hole 51 ' a, the pressure sensor 67 measures the pressure in the housing space 11 ', that is, the internal pressure inside the exterior portion 3 '. The metal fitting 65 is attached to a diagonal position with respect to the opening hole 51 ' a, that is, to the vicinity of the corner formed by the side walls 8 ' B and 8 ' D. As the accessory 65, a product of model M3-ALU-4 manufactured by SMC was used. Further, as the pressure sensor 67, a pressure sensor 67 having a model number AP-10S manufactured by KEYENCE and a rated pressure range of. + -. 100kPa was used.

In the verification, under three conditions α 1 to α 3, the gas is discharged from the opening-sealing hole 51 ' a, and the temporal change in the degree of pressure reduction ∈ of the storage space 11 ' from the start of gas discharge is measured, and the measurement of the temporal change in the degree of pressure reduction ∈ is performed twice for each of conditions α 1 to α 3, where condition α 1 is configured such that only the opening-sealing hole 51 ' a is provided in a region outside the edge 15 ' of the opening 12 ' and inside the edges 46 ' to 48 ', 50 ', and therefore condition α 1 is not provided with a configuration corresponding to the above-described convex portion 52A (including 52A1, 52A2), and in condition α 2, in a region outside the edge 15 ' of the opening 12 ' and inside the welding portions 46 ' to 48 ', 50 ', in addition to the opening-sealing portion 51 ' a, a region outside the edge 15 ' of the opening 12 ' and inside the welding portions 46 ' to 48 ', 50 ' is provided with a convex portion 52 ' a having the same shape as the convex portion 52A in the flange 13 ' and the width of the opening-sealing portion 52A2, and the convex portion 52A is formed in the same width from the opening-sealing portion 52A 4 ' a, and the width of the opening-sealing portion 52A2, and the top plate 52A is formed with the same length, and the same width as the width of the convex portion 52A2, and the width of the opening 52A2, and the top plate 52A2, and the width of the convex portion 52 ' is formed with the width, the width of the opening 52A2, the top plate 52A, the width of the top plate 52A2, the top plate 52A 4mm, the top plate 52A, the.

In condition α, 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 flange 13 'is provided with the projections 52' a1, 52 'a 2 which are the same as the projections 52a1, 52a2 (see fig. 8A, 8B) of the second embodiment described above, and is formed in the same tunnel ceiling shape as the projection 52a1 and in the same position as the projection 52a1 with respect to the projection 52' a1, and the projection 52 'a 2 is formed in the same tunnel ceiling shape as the projection 52a2 and in the same position as the projection 52a2, the projections 52' a1, 52 'a 2 are formed with the longitudinal dimension (one corresponding to the D' 5a and D '6 a) of 10mm, the width in the width direction (one corresponding to the W' 2a and W '3 a) is set to be equal to the width in the width from the opening hole 631.2 a, the opening hole 582 a 632 a, the opening hole 2' a is set to the opening hole 6a, and the projection 52 'a is set to the opening distance 582 a 2a 5966 a, and the projection 52' a is set to the distance equal to 2a2, 2 A6 a2, 2 A6 a, 2a, and P6 a are set to 5a, and P2a, and.

Fig. 20 shows the measurement result of the temporal change in the degree of pressure reduction ∈ of the storage space 11 'under verification, in fig. 20, the horizontal axis shows the time t based on the start of discharge of gas from the opening hole 51' a, and the vertical axis shows the degree of pressure reduction ∈.

As shown in fig. 20, under the condition α 1, the reduced pressure degree ∈ was-70 kPa or more and-60 kPa or less at the time when 5 minutes elapsed from the start of gas discharge, that is, under the condition α 1, the reduced pressure degree ∈ did not reach-90 kPa even when 5 minutes elapsed from the start of gas discharge, and under the condition α 1, after 5 minutes elapsed from the start of gas discharge, the flange 13 ' and the second outer package member 6 ' were pulled in a direction away from each other by a mechanical force, and at this time, the flange 13 ' and the second outer package member 6 ' were mechanically pulled between the edge 15 ' of the opening 12 ' and the opening 51 ' a, and the reduced pressure degree ∈ was maintained at-70 kPa or more and-60 kPa or less, that is, even if the flange 13 ' and the second outer package member 6 ' were mechanically pulled, the reduced pressure degree ∈ did not change substantially, that is, and was maintained at-70 kPa and-60 kPa or less even when the flange 13 ' and the second outer package member 6 ' were mechanically pulled.

Further, under condition α 2, the degree of reduced pressure ∈ reached-90 kpa at the time when 3 minutes elapsed from the start of gas discharge, so it was verified that, in the configuration of the first embodiment or the like in which the convex portion 52A (52B) similar to the convex portion 52' a was provided, even if the internal pressure was lower than the external pressure, the gas reached the open-cell hole (corresponding one of 51A, 51B) and was appropriately discharged to the outside of the exterior package portion 3.

Further, under the condition α 3, the reduced pressure degree ∈ reached-90 kPa or less at the time when 1 minute elapsed from the start of the discharge of the gas, and therefore, it was verified that, in the configuration of the second embodiment in which the convex portions 52a1 and 52a2(52B1 and 52B2) similar to the convex portions 52 'a 1 and 52' a2 were provided, the gas more easily flowed from the storage space 11 to the corresponding one of the unsealing

holes

51A and 51B) and was more efficiently discharged to the outside of the outer package portion 3 in a state in which the internal pressure was lower than the external pressure.

(modification example)

In the above-described embodiment, the gas is discharged to the outside from the opening hole (first opening position) 51A before the charging and the aging, and the gas is discharged to the outside from the opening hole (second opening position) 51B after the charging and the aging, but the present invention is not limited thereto. In a modification, the gas is discharged to the outside from the opening hole (second opening position) 51B before the charging and the aging, and the gas is discharged to the outside from the opening hole (first opening position) 51A after the charging and the aging. In this case, in the manufacture of the secondary battery 1, the opening hole (second opening hole) 51B is formed in the flange 13 in the formation of the flange 13, or the opening hole 51B is formed in the second exterior packaging member 6 in the formation of the second exterior packaging member 6. After the gas is discharged from the opening hole 51B, the welded portion 53B is formed, and the housing space 11 is sealed from the outside of the outer package portion 3 by the welded portions 46 to 48, 50, and 53B. After aging or the like, the opening hole (first opening hole) 51A is formed in a state where the housing space 11 is sealed by the welding portions 46 to 48, 50, and 53B. Then, the gas generated by the aging is released from the formed opening hole 51A to the outside of the external packaging member 3. When the gas is released from the opening hole 51A, the welded portion 53A is formed, and the housing space 11 is sealed again from the outside of the outer package portion 3 by the welded portions 46 to 48, 50, 53A, and 53B.

In the manufacturing method of the above-described embodiment and the like, the secondary battery 1 in which only one electrode group 10 is housed in the housing space 11 is manufactured, but in a modification, the secondary battery 1 in which a plurality of electrode groups are housed in the housing space 11 may be manufactured in the same manner as in the above-described embodiment.

In a modification, the second outer cover 6 is not plate-shaped but formed in a bottomed tubular shape similar to the first outer cover 5. In this case, the second outer jacket material 6 is also formed to have a bottom wall, a side wall, and a flange. The flange 13 of the first outer jacket material 5 and the flange of the second outer jacket material 6 are hermetically welded by welds 45 to 48 and the like. In the secondary battery 1 manufactured by the manufacturing method of the present modification, the flange 13 and the second exterior member 6 are also hermetically welded over the entire circumference in the circumferential direction of the opening 12 by the welding portions 45 to 48. The housing space 11 for housing the electrode group 10 is sealed from the outside of the exterior package portion 3.

According to the method of manufacturing a secondary battery of at least one of the embodiments or examples, the second outer covering member is disposed to face the flange of the first outer covering member in a state where the protruding portion protrudes from one of the flange and the second outer covering member toward the other and the protruding portion is located outside the edge of the opening. The flange and the second outer package member are hermetically welded by the welded portion outside the projection, and the gas in the storage space is discharged from the unsealing position between the welded portion and the projection and in the vicinity of the projection. Therefore, a method for manufacturing a secondary battery in which gas is appropriately discharged from the housing space to the outside at the time of manufacturing can be provided.

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

Claims

1. A method for manufacturing a secondary battery, comprising the steps of:

a first outer package member formed of stainless steel, the first outer package member defining a housing space defined by a bottom wall and a side wall, the housing space having an opening on a side opposite to the bottom wall;

forming a flange at a position on a side opposite to the bottom wall in a process of forming the first outer package member, the flange defining an edge of the opening of the housing space;

forming an electrode group including a positive electrode and a negative electrode;

forming a second outer wrapper component from stainless steel;

forming a first protrusion on the flange in the process of forming the flange, or forming a first protrusion on the second exterior packaging member in the process of forming the second exterior packaging member;

configuring the second exterior packaging member in a state: in a state where the electrode group is disposed in the housing space, the second outer jacket material is disposed so as to face the flange, the opening of the housing space is closed, the first protruding portion formed on one of the flange and the second outer jacket material is disposed outside the edge of the opening, and the first protruding portion protrudes toward the other of the flange and the second outer jacket material;

hermetically welding the flange and the second exterior member to the outside of the first projection over the entire circumference of the opening to form a first welded portion; and

and discharging the gas in the housing space from a first unsealing position between the first welding portion and the first convex portion and in the vicinity of the first convex portion.

2. The method for manufacturing a secondary battery according to claim 1,

when the first convex portion is formed, the first convex portion is formed into a tunnel ceiling shape.

3. The method for manufacturing a secondary battery according to claim 1,

in forming the first convex portion, the first convex portion is formed in a dome shape.

4. The method for manufacturing a secondary battery according to claim 1,

when the first convex portions are formed, the plurality of first convex portions are formed in a state of being arranged in a predetermined direction in proximity to each other.

5. The method for manufacturing a secondary battery according to claim 4,

forming the plurality of first protrusions in a tunnel ceiling shape, respectively, when forming the plurality of first protrusions,

when the plurality of first convex portions are formed, the plurality of first convex portions are formed so as to extend parallel or substantially parallel to each other, and the predetermined direction in which the plurality of first convex portions are arranged is perpendicular or substantially perpendicular to the longitudinal direction of each of the plurality of convex portions.

6. The method for manufacturing a secondary battery according to any one of claims 1 to 5,

forming the first outer jacket material to have a thickness of 0.02mm or more and 0.3mm or less,

in forming the second outer jacket material, the second outer jacket material is formed to have a thickness of 0.02mm or more and 0.3mm or less.

7. The method for manufacturing a secondary battery according to any one of claims 1 to 6,

further comprises the following steps: after the gas is discharged from the first unsealing position, the flange and the second outer package member are hermetically welded between the first unsealing position and the first convex portion, and the path of the gas is cut between the first unsealing position and the first convex portion.

8. The method for manufacturing a secondary battery according to any one of claims 1 to 7,

further comprising a step of injecting an electrolyte into the housing space in a state where the electrode group is housed in the housing space,

the step of forming the first weld includes:

hermetically welding the flange and the second exterior member only over a part of the circumferential direction of the opening before injecting the electrolyte; and

after the electrolyte is injected from a portion where the flange and the second exterior packaging member are not welded, the flange and the second exterior packaging member are hermetically welded in a range where the flange and the second exterior packaging member are not welded in the circumferential direction of the opening.

9. The method for manufacturing a secondary battery according to any one of claims 1 to 8,

further comprising a step of forming a hole in the flange in the process of forming the flange or forming a hole in the second exterior packaging member in the process of forming the second exterior packaging member,

the step of disposing the second outer jacket material so as to face the flange includes disposing the second outer jacket material in a state where the opening hole is located outside the first convex portion and in the vicinity of the first convex portion,

the step of forming the first welded portion includes forming the first welded portion outside the opening hole,

the step of discharging the gas from the first unsealing position includes discharging the gas from the open hole at the first unsealing position.

10. The method for manufacturing a secondary battery according to any one of claims 1 to 8,

further comprising a step of forming an opening hole between the first welded part and the first convex part and in the vicinity of the first convex part after the first welded part is formed,

11. The method for manufacturing a secondary battery according to any one of claims 1 to 10, comprising the steps of:

after the gas is discharged from the first unsealing position, hermetically welding the flange and the second outer package member inside the first projection to form a second weld, and cutting a path of the gas between the edge of the opening and the first projection by the second weld; and

the flange and the second outer jacket material are cut at an outer portion thereof by the second weld, and the first protruding portion and the first unsealing position are removed.

12. The method for manufacturing a secondary battery according to any one of claims 1 to 10, comprising the steps of:

forming a second convex portion at a position of the flange apart from the first convex portion in the process of forming the flange, or forming a second convex portion at a position of the second exterior packaging member apart from the first convex portion in the process of forming the second exterior packaging member,

the step of disposing the second outer jacket material so as to face the flange includes: the second outer package member is disposed in a state in which the second protruding portion formed on one of the flange and the second outer package member is disposed outside the edge of the opening and the second protruding portion protrudes toward the other of the flange and the second outer package member,

the step of forming the first weld includes forming the first weld outside the second projection,

the manufacturing method further comprises the following steps: before or after the gas is discharged from the first unsealing position, the gas in the storage space is discharged from a second unsealing position between the first welded portion and the second convex portion and in the vicinity of the second convex portion.

13. The method of manufacturing a secondary battery according to claim 12,

further comprises the following steps: after the gas is discharged from the second unsealing position, the flange and the second outer package member are hermetically welded between the second unsealing position and the second convex portion, and the path of the gas is cut between the second unsealing position and the second convex portion.

14. The method for manufacturing a secondary battery according to claim 12 or 13,

the manufacturing method comprises the following steps:

after both the gas is discharged from the first unsealing position and the gas is discharged from the second unsealing position, hermetically welding the flange and the second outer package member inside the first projection and the second projection to form a second weld, and cutting off the path of the gas between the edge of the opening and the first projection and between the edge of the opening and the second projection by the second weld; and

the flange and the second outer jacket material are cut at outer portions thereof by the second weld portion, and the first convex portion, the second convex portion, the first unsealing position, and the second unsealing position are removed.