WO2022254663A1

WO2022254663A1 - Battery sealing method, battery production method, and battery

Info

Publication number: WO2022254663A1
Application number: PCT/JP2021/021222
Authority: WO
Inventors: 稔英有川
Original assignee: 株式会社東芝
Priority date: 2021-06-03
Filing date: 2021-06-03
Publication date: 2022-12-08
Also published as: JPWO2022254663A1

Abstract

An embodiment of the present invention provides a battery sealing method. This battery sealing method seals a battery which is equipped with a positive electrode, a negative electrode and an outer member provided with a liquid pouring spout. The liquid pouring spout is equipped with a first hole which faces the inner wall of the outer member, and a second hole which faces the outer wall of the outer member and is connected to the first hole. The second hole has a larger diameter than does the first hole. The battery sealing method includes a liquid-pouring step, a first sealing step, a gas generation step, a gas discharge step, and a second sealing step. The first sealing step involves temporarily sealing the first hole with a temporary sealing plug. The gas discharge step involves removing the temporary sealing plug, and discharging gas generated inside the outer member through the liquid pouring spout. The second sealing step involves placing a sealing lid on the outer wall of the outer member so as to cover the liquid pouring spout, and welding the sealing lid onto the outer member.

Description

Battery sealing method, battery manufacturing method, and battery

Embodiments of the present invention relate to a battery sealing method, a battery manufacturing method, and a battery.

　Secondary batteries, typified by lithium-ion secondary batteries, are traded at high prices, but defective batteries occur at a certain rate in the battery manufacturing process. Defects that occur in the process closer to completion of a battery are more costly to the manufacturer because more materials have been used and more processing has been done.

The sealing process is one of the processes in which many defects occur in the actual battery manufacturing process. In the sealing process, for example, a temporary sealing process, a degassing process, and a final sealing process are performed. In the temporary sealing step, the electrolytic solution is injected into the battery through the injection port, and the injection port is closed with a temporary sealing plug. After that, gas is generated inside the battery under predetermined conditions. In the degassing step, the temporary sealing plug is removed and the generated gas is withdrawn from the inlet. In the main sealing step, a sealing lid is placed so as to cover the liquid injection port, and the lid is welded to permanently seal the battery. Defects that occur in the main sealing process are particularly damaging because they occur after all the members necessary for manufacturing the battery have been assembled.

Therefore, there is a demand for means for suppressing defects that occur in the sealing process.

Japanese Patent Application Laid-Open No. 2004-296192 Japanese Patent Application Laid-Open No. 2008-041548 Japanese Patent Application Laid-Open No. 2009-087659 Japanese Patent Application Laid-Open No. 2010-157415 Japanese Patent Application Laid-Open No. 2014-170648 Japanese Patent Application Laid-Open No. 2000-268811

The present invention aims to provide a battery sealing method capable of sealing a battery with a high yield, a battery manufacturing method including a step of sealing a battery by this sealing method, and a battery capable of achieving a high yield. aim.

According to the embodiment, a battery sealing method is provided. A battery sealing method is a method of sealing a battery including a positive electrode, a negative electrode, and an exterior member having a liquid inlet. The liquid inlet has a first hole facing the inner wall of the exterior member, and a second hole communicating with the first hole and facing the outer wall of the exterior member. The second hole has a larger diameter than the first hole. A battery sealing method includes a liquid filling step, a first sealing step, a gas generating step, a gas releasing step, and a second sealing step. The injection step is a step of injecting the electrolytic solution into the exterior member through the injection port. A 1st sealing process is a 1st sealing process which temporarily seals a 1st hole with a temporary sealing plug. The gas generation step is a step of generating gas in the exterior member by heating the exterior member and/or subjecting the battery to initial charging. The gas releasing step is a step of removing the temporary sealing plug and releasing the gas generated in the exterior member from the inlet. The second sealing step is a step of placing a sealing lid on the outer wall of the exterior member so as to cover the liquid inlet and welding the sealing lid to the exterior member.

According to another embodiment, a method of manufacturing a battery is provided. The battery manufacturing method includes a step of housing an electrode group including a positive electrode, a negative electrode, and a separator in an exterior member, and a step of sealing the battery by the battery sealing method according to the embodiment.

According to another embodiment, a battery is provided. A battery includes an exterior member and an electrode group. The exterior member includes a liquid inlet and a sealing lid. The electrode group is housed in the exterior member and includes a positive electrode, a negative electrode and a separator. The liquid inlet has a first hole facing the inner wall of the exterior member and a second hole communicating with the first hole and facing the outer wall of the exterior member, the second hole being compared with the first hole. diameter is large. The sealing lid is welded to the outer wall of the exterior member to seal the injection port.

1 is an exploded perspective view of a battery according to an embodiment; FIG. FIG. 2 is a partially exploded perspective view of the battery shown in FIG. 1 as seen from below; FIG. 2 is a partially exploded perspective view of an electrode group used in the battery shown in FIG. 1; FIG. 2 is a perspective view of the battery shown in FIG. 1; FIG. 2 is a top view of the battery shown in FIG. 1; FIG. 6 is a top view showing an enlarged portion A of FIG. 5 ; Sectional drawing of the battery along the VII-VII line of FIG. FIG. 4 is a schematic cross-sectional view showing a liquid injection port of a battery according to a reference example; FIG. 9 is a cross-sectional view schematically showing one step of the battery sealing method according to the reference example shown in FIG. 8 ; FIG. 9 is a cross-sectional view schematically showing one step of the battery sealing method according to the reference example shown in FIG. 8 ; FIG. 9 is a cross-sectional view schematically showing one step of the battery sealing method according to the reference example shown in FIG. 8 ; FIG. 9 is a cross-sectional view schematically showing one step of the battery sealing method according to the reference example shown in FIG. 8 ; FIG. 4 is a cross-sectional view schematically showing an example of an injection step in the battery sealing method according to the embodiment; FIG. 4 is a cross-sectional view schematically showing an example of a first sealing step in the battery sealing method according to the embodiment. FIG. 4 is a cross-sectional view schematically showing another example of the first sealing step in the battery sealing method according to the embodiment; FIG. 4 is a cross-sectional view schematically showing another example of the first sealing step in the battery sealing method according to the embodiment; FIG. 4 is a cross-sectional view schematically showing an example of a gas generation step in the battery sealing method according to the embodiment; FIG. 4 is a cross-sectional view schematically showing an example of a gas release step in the battery sealing method according to the embodiment; FIG. 4 is a cross-sectional view schematically showing an example of a second sealing step in the battery sealing method according to the embodiment; FIG. 4 is a cross-sectional view schematically showing an example of a second sealing step in the battery sealing method according to the embodiment; FIG. 4 is a cross-sectional view schematically showing another example of the liquid inlet in the battery sealing method according to the embodiment; FIG. 4 is an enlarged schematic cross-sectional view showing the vicinity of the liquid injection port sealed by the battery sealing method according to the embodiment;

Embodiments will be described below with reference to the drawings. In addition, the same code|symbol shall be attached|subjected to the common structure through embodiment, and the overlapping description is abbreviate|omitted. In addition, each drawing is a schematic diagram for explaining the embodiments and promoting understanding thereof, and there are places where the shapes, dimensions, ratios, etc. are different from the actual device, but these are the following explanations and known techniques. Consideration can be taken into consideration and the design can be changed as appropriate.

(First embodiment)
According to a first embodiment, a battery sealing method is provided. A battery sealing method is a method of sealing a battery including a positive electrode, a negative electrode, and an exterior member having a liquid inlet. A battery sealing method includes a liquid filling step, a first sealing step, a gas generating step, a gas releasing step, and a second sealing step.

Before describing the battery sealing method, an example of a battery obtained by the battery sealing method according to the embodiment will be described with reference to FIGS. The battery may be a non-aqueous electrolyte secondary battery. The battery is a sealed prismatic non-aqueous electrolyte battery. The battery includes an exterior member 1 , a flat electrode group 2 housed in the exterior member 1 , and a non-aqueous electrolyte (not shown) impregnated in the flat electrode group 2 . The exterior member 1 has a bottomed prismatic container 3 and a sealing plate 4 fixed to the opening of the container 3 by, for example, welding.

FIG. 1 is an exploded perspective view of the battery according to the embodiment. FIG. 2 is a partially exploded perspective view of the battery shown in FIG. 1 as seen from below. 3 is a partially exploded perspective view of an electrode group used in the battery shown in FIG. 1. FIG. 4 is a perspective view of the battery shown in FIG. 1. FIG. 5 is a top view of the battery shown in FIG. 1. FIG.

As shown in FIG. 3, the flat electrode group 2 is formed by winding a positive electrode 5 and a negative electrode 6 in a flat shape with a separator 7 interposed therebetween. The positive electrode 5 includes, for example, a strip-shaped positive electrode current collector made of metal foil, a positive electrode current collector tab 5a composed of one end parallel to the long side of the positive electrode current collector, and a positive electrode except for at least the positive electrode current collector tab 5a. and a positive electrode active material layer 5b formed on the current collector. On the other hand, the negative electrode 6 includes, for example, a strip-shaped negative electrode current collector made of metal foil, a negative electrode current collector tab 6a composed of one end portion parallel to the long side of the negative electrode current collector, and at least the negative electrode current collector tab 6a being excluded. and a negative electrode active material layer 6b formed on the negative electrode current collector.

In such positive electrode 5, separator 7 and negative electrode 6, the positive electrode collector tab 5a protrudes from the separator 7 in the direction of the winding axis of the electrode assembly, and the negative electrode collector tab 6a protrudes from the separator 7 in the opposite direction. , the positions of the positive electrode 5 and the negative electrode 6 are shifted. By such winding, as shown in FIG. 3, in the electrode group 2, the spirally wound positive electrode current collecting tab 5a protrudes from one end face and is spirally wound from the other end face. A negative electrode current collecting tab 6a protrudes.

As shown in FIGS. 1 and 2, the positive lead 8 includes a connection plate 8a for electrically connecting to the positive electrode terminal 9, a through hole 8b formed in the connection plate 8a, and a bifurcated branch from the connection plate 8a. and a strip-shaped collector portion 8c extending downward. The current collecting portion 8c of the positive lead 8 sandwiches the positive current collecting tab 5a of the electrode group 2 therebetween and is electrically connected to the positive current collecting tab 5a by welding. On the other hand, the negative electrode lead 10 includes a connection plate 10a for electrically connecting to the negative electrode terminal 11, a through hole 10b opened in the connection plate 10a, and a strip extending downward from the connection plate 10a. and a current collecting portion 10c. The current collecting portion 10c of the negative electrode lead 10 sandwiches the negative electrode current collecting tab 6a of the electrode group 2 therebetween and is electrically connected to the negative electrode current collecting tab 6a by welding. A method for electrically connecting the positive and

negative leads

8 and 10 to the positive and negative

current collecting tabs

5a and 6a is not particularly limited, but examples thereof include welding such as ultrasonic welding and laser welding.

The electrode guard 12 has a side plate 12a that covers the end faces of the positive and negative electrode

current collecting tabs

5a and 6a, and a side plate 12b curved in a U shape so as to cover the outermost periphery of the positive and negative electrode

current collecting tabs

5a and 6a. The top end of the electrode guard 12 is open to receive the electrode group 2 therefrom. The positive electrode current collecting tab 5a of the electrode group 2 is covered with the electrode guard 12 while the current collecting portion 8c of the positive electrode lead 8 is welded thereto. A connection plate 8 a of the positive lead 8 is positioned above the electrode guard 12 . On the other hand, the negative electrode current collecting tab 6a of the electrode group 2 is covered with the electrode guard 12 while the current collecting portion 10c of the negative electrode lead 10 is welded thereto. A connection plate 10 a of the negative lead 10 is positioned above the electrode guard 12 . Two electrode guards 12 are fixed to the electrode group 2 with an insulating tape 13 .

As shown in FIGS. 1 and 2, the sealing plate 4 has a rectangular plate shape. The sealing plate 4 has through

holes

4 a and 4 b for attaching the positive and

negative terminals

9 and 11 . Also, the sealing plate 4 has a liquid injection port 20 . The through-holes provided in the sealing plate 4 can be only three, the through-

holes

4 a and 4 b and the injection port 20 . In this case, since the injection port 20 also serves as a gas vent hole, there is no need to provide a separate gas vent hole. Therefore, there is an advantage that the manufacturing process of the sealing plate 4 can be reduced. In addition, the liquid injection port 20 may be provided on the wall surface of the bottomed prismatic container 3 .

The injection port 20 is also used to release gas generated inside the battery after the electrolyte is injected through it. The details of the injection port 20 will be described later with reference to FIGS. 6 and 7. FIG. The injection port 20 is sealed with a sealing lid 14 . The sealing lid 14 here has a disk-like shape. The sealing lid 14 is fixed to the surface of the sealing plate 4 by welding, for example. FIG. 5 shows a top view of the sealing plate 4 to which the sealing lid 14 is attached. The sealing lid 14 is made of, for example, metal such as aluminum or aluminum alloy. Further, the shape of the sealing lid 14 is not limited to a disk shape, and can be changed as appropriate according to the shape of the liquid injection port.

As shown in FIG. 2, an insulating plate 16 is arranged on the rear surface of the sealing plate 4 . The insulating plate 16 has a concave portion 16a in which the connection plate 8a of the positive electrode lead 8 is accommodated at one end and a concave portion 16b in which the connection plate 10a of the negative electrode lead 10 is accommodated at the other end. An opening is provided between the recess 16a and the recess 16b, and the rear surface of the sealing plate 4 is exposed. Further, the

recesses

16a and 16b of the insulating plate 16 have through holes communicating with the through

holes

4a and 4b of the sealing plate 4, respectively.

The positive and

negative terminals

9, 11 respectively have rectangular plate-shaped

heads

9a, 11a and

shafts

9b, 11b extending from the

heads

9a, 11a. The insulating gasket 17 has through holes 17a into which the

shafts

9b and 11b of the positive and

negative terminals

9 and 11 are inserted. The shaft portion 9b of the positive electrode terminal 9 is inserted into the through hole 17a of the insulating gasket 17, the through hole 4a of the sealing plate 4, the through hole of the insulating plate 16, and the through hole 8b of the connection plate 8a of the positive electrode lead 8. It is crimped and fixed. Thereby, the positive electrode terminal 9 is electrically connected to the positive electrode current collecting tab 5a via the positive electrode lead 8 . On the other hand, the shaft portion 11b of the negative electrode terminal 11 is inserted into the through hole 17a of the insulating gasket 17, the through hole 4b of the sealing plate 4, the through hole of the insulating plate 16, and the through hole 10b of the connection plate 10a of the negative electrode lead 10. It is caulked and fixed to the member. Thereby, the negative electrode terminal 11 is electrically connected to the negative electrode current collecting tab 6a via the negative electrode lead 10 .

FIG. 6 is a top view showing an enlarged portion A of FIG. 7 is a cross-sectional view of the battery according to FIG. 4 along line VII-VII. A sealing lid 14 is welded onto the surface of the sealing plate 4 . The sealing plate 4 has a welded portion 50 connected to the sealing lid 14 . The sealing lid 14 and the welded portion 50 block the injection port 20 . As shown in FIG. 7 , the liquid injection port 20 includes a first hole 21 facing the back surface of the sealing plate 4 , that is, the inner wall of the exterior member 1 , and a first hole 21 facing the surface of the sealing plate 4 , that is, the outer wall of the exterior member 1 . 2 holes 22 . The first hole 21 and the second hole 22 communicate with each other as shown in FIG. In other words, the liquid injection port 20 is a through hole penetrating the wall surface of the exterior member 1 along the thickness direction. The liquid injection port 20 may be provided so as to penetrate the sealing plate 4 of the exterior member 1 or may be provided so as to penetrate the wall surface of the bottomed prismatic container 3 .

The diameter of the second hole 22 is larger than that of the first hole 21 . In the specification and claims of the present application, the diameter of the first hole 21 refers to the diameter of the hole at the position of the boundary 21 a between the first hole 21 and the second hole 22 . The boundary 21 a is also referred to as the open end 21 a of the first hole 21 . Also, the diameter of the second hole 22 refers to the diameter of the opening end 22 a of the second hole 22 facing the surface of the sealing plate 4 . A specific method for measuring the diameter of the first hole 21 and the diameter of the second hole 22 will be described later.

6 and 7 show the case where the first hole 21 defines a cylindrical hollow portion as an example, but the shape of the first hole 21 is not limited to this. The shape of the first hole 21 may define, for example, a prism-shaped hollow portion or a cone-shaped hollow portion. The shape of the opening end 21a of the first hole 21 may be circular, or polygonal such as rectangular or square. In addition, in FIGS. 6 and 7, as an example, the shape of the second hole 22 is such that the diameter continuously decreases from the open end 22a of the second hole 22 toward the open end 21a of the first hole 21 ( tapered). In this case, the electrolytic solution adhering to the inner wall of the second hole 22 after the injection of the electrolytic solution easily flows toward the first hole 21 and further toward the interior of the exterior member, which is preferable. The shape of the second hole 22 may have a hemispherical shape with a reduced diameter as shown in FIG. 7, or may have a conical shape with a reduced diameter. The shape of the second hole 22 may be cylindrical like the first hole 21, or may be prismatic.

Next, with reference to FIGS. 8 to 12, problems that occur when sealing a battery having a conventional liquid injection port 200 will be described.

FIG. 8 is a cross-sectional view schematically showing the periphery of the liquid injection port 200 of the battery according to the reference example. The liquid injection port 200 is a through hole that penetrates the sealing plate 4 along the thickness direction. The battery according to the reference example has the same structure as the battery shown in FIGS. 1 to 7, except that the structure of the injection port is different.

Electrolyte is injected into the exterior member through the injection port 200 . For example, a nozzle (not shown) is arranged on the surface side of the sealing plate 4 and in the vicinity of the liquid injection port 200 , and the electrolytic solution is discharged from the nozzle toward the liquid injection port 200 . Most of the discharged electrolytic solution is injected into the exterior member. However, a small amount of the electrolytic solution 30 may adhere to the inner wall of the inlet 200 and the surface of the sealing plate 4 as shown in FIG. FIG. 9 is a cross-sectional view schematically showing a state in which the electrolytic solution 30 adheres around the injection port 200. As shown in FIG.

FIG. 10 is a cross-sectional view schematically showing a state in which the temporary sealing plug 40 is inserted into the injection port 200 shown in FIG. The temporary sealing plug 40 has a head portion 41 and a shaft portion 42 extending from the head portion 41 . The head 41 of the temporary sealing plug 40 is gripped by, for example, an arbitrarily selected device, and after the position is adjusted, the shaft 42 is inserted into the injection port 200 .

When the temporary sealing plug 40 is inserted into the injection port 200 to which the electrolytic solution 30 has adhered, between the shaft portion 42 and the injection port 200 and between the head portion 41 and the surface 4c of the sealing plate 4, The electrolytic solution 30 is pushed and spread.

With the temporary sealing plug 40 inserted into the liquid inlet 200, the battery is subjected to the gas generation process under predetermined conditions. Specifically, for example, gas is generated in the exterior member by heating the exterior member and/or subjecting the battery to initial charging. The gas is generated, for example, by the reaction between the electrolyte and the electrode material. During this time, the electrolytic solution 30 may dry and crystallize over time.

FIG. 11 is a cross-sectional view schematically showing a state in which the temporary sealing plug 40 is pulled out from the injection port 200 after the gas generation step. The gas generated inside the exterior member in the above gas generation step is discharged from the injection port 200 . On the other hand, crystals 31 of the electrolytic solution adhere to the periphery of the liquid injection port 200 , for example, the inner wall of the liquid injection port 200 and the surface 4 c of the sealing plate 4 .

FIG. 12 is a cross-sectional view schematically showing a state after the sealing lid 14 is placed on the liquid inlet 200 shown in FIG. 11 and then welded to the sealing plate 4 . If the electrolyte crystals 31 adhere around the liquid injection port 200 , the electrolyte crystals 31 are caught between the surface 4 c of the sealing plate 4 and the sealing lid 14 . If a laser is radiated in this state and welding is attempted, the heat conduction from the sealing lid 14, which is heated by the laser, to the sealing plate 4 will be insufficient, and the sealing plate 4 will be sealed by the gas generated from the crystals. The stopper lid 14 cannot be uniformly melted. As a result, for example, a pinhole 140 may occur near the welded portion 50 . The pinhole 140 deteriorates the sealing performance of the battery, which in turn reduces the yield of the battery.

From the situations shown in FIGS. 8 to 12 as reference examples described above, there are, for example, two factors that cause welding to fail. The first factor is that the crystals 31 of the electrolytic solution are present on the surface of the sealing plate 4 and at the welded portion, which hinders heat conduction from the sealing lid 14 to the sealing plate 4 . The second factor is that since the crystals 31 of the electrolytic solution are present between the sealing plate 4 and the sealing lid 14, the sealing lid 14 is lifted, and the sealing plate 4 and the sealing lid 14 do not adhere to each other. It is the prevention of sexuality.

According to the method for sealing the battery according to the present embodiment, it is possible to prevent the electrolyte crystals 31 from sticking to the surface of the sealing plate 4 . As a result, the adhesion between the sealing lid 14 and the sealing plate 4 can be ensured during welding, so that the occurrence of defects such as pinholes can be suppressed. As a result, the yield of batteries can be improved.

A battery sealing method according to an embodiment will be described below with reference to FIGS. 13 to 21. FIG.

First, prepare a battery that includes a positive electrode, a negative electrode, and an exterior member that has an injection port. At this time, it is desirable to prevent moisture from entering the exterior member as much as possible. The injection port has the structure described with reference to FIG. 7, for example. That is, the liquid injection port 20 includes a first hole 21 facing the inner wall of the exterior member (sealing plate 4) and a second hole 22 communicating with the first hole 21 and facing the outer wall of the exterior member. , the second hole 22 has a larger diameter than the first hole 21 .

Next, the electrolytic solution is injected through the injection port 20 into the exterior member. When injecting the electrolytic solution, the inside of the exterior member may be previously decompressed compared to the outside. This makes it easy to inject the electrolytic solution into the exterior member even if the injection port 20 is relatively small. As shown in FIG. 13, the electrolytic solution 30 may adhere around the injection port 20 after the injection. However, in the liquid injection port 20 according to the embodiment, the electrolytic solution 30 mainly adheres to the inner wall of the second hole 22 . Therefore, the electrolytic solution 30 does not adhere to the surface 4c of the sealing plate 4, or adheres with difficulty. On the other hand, even if the electrolyte seeps out from the interior of the exterior member to the exterior through the injection port 20 , the electrolyte does not easily reach the surface 4 c of the sealing plate 4 .

Next, a temporary sealing plug 40 is inserted into the first hole 21 to temporarily seal the battery. The step of performing temporary sealing is also referred to as a first sealing step in the specification and claims of the present application. Temporary sealing by the temporary sealing plug 40 is performed, for example, by closing the opening end 21a of the first hole 21 with the shaft portion 42 of the temporary sealing plug 40, as shown in FIG. The electrolytic solution 30 mainly adheres to the inner walls of the second holes 22 . Therefore, even if the temporary sealing plug 40 is inserted into the first hole 21 , the adhering electrolytic solution 30 is less likely to be spread by the temporary sealing plug 40 .

The shape of the temporary sealing plug 40 is not particularly limited as long as it can temporarily seal the first hole 21 . The head 41 of the temporary sealing plug 40 is gripped by, for example, an arbitrarily selected device, and the shaft portion 42 is inserted into the first hole 21 after the position is adjusted. The head 41 has, for example, a columnar shape or a cuboid shape. The shaft portion 42 is connected to the main surface of the head portion 41 and is, for example, a semi-conical body tapering from this connecting portion. The shape of the head 41 and the shape of the shank 42 can be determined independently of each other.

The head 41 of the temporary sealing plug 40 is made of, for example, polyphenylene ether (PPE), polyetheretherketone (PEEK), polyethylene (PE), polypropylene (PP), polybutylene terephthalate (PBT), polytetrafluoroethylene ( It is at least one resin selected from the group consisting of tetrafluoroethylene (PTFE) and polyvinyl chloride (PVC). It is preferable that the head 41 is made of a material that has an appropriate hardness so as not to be deformed even when the head 41 is gripped and that does not dissolve in the electrolytic solution. At least one resin as described above fulfills this requirement.

The shaft portion 42 of the temporary sealing plug 40 is made of, for example, at least one selected from the group consisting of ethylene propylene diene terpolymer (EPDM) and fluoroethylene perfluoroalkyl vinyl ether copolymer (FFKM). Resin. The material of the shaft portion 42 is preferably a material that can reliably seal the battery when the shaft portion 42 is inserted into the first hole 21 and that does not dissolve in the electrolytic solution. At least one resin as described above fulfills this requirement.

In the state where the first hole 21 is temporarily sealed by the temporary sealing plug 40, as shown in FIG. is preferably provided. When the gap G is provided in the first sealing step, it is possible to reduce the possibility that the electrolytic solution 30 will spread over the surface 4 c of the sealing plate 4 . When the gap G is provided, the distance between the temporary sealing plug 40 and the surface 4c of the sealing plate 4 is, for example, 0.05 mm or more, preferably 0.2 mm, at the point where they are closest to each other. That's it. That is, the distance between the temporary sealing plug 40 and the surface 4c of the sealing plate 4 can be at least 0.05 mm or more. Although the upper limit of the distance is not particularly limited, it is, for example, 5.0 mm.

As shown in FIG. 15, the temporary sealing plug 40 may consist of the shaft portion 42 only. In this case, the above-mentioned problem that can occur when the temporary sealing plug 40 is provided with the head 41, that is, the head 41 may spread the electrolytic solution 30 over the surface 4c of the sealing plate 4. problem does not occur.

Also, the temporary sealing plug 40 may have the shape shown in FIG. A head portion 41 provided in the temporary sealing plug 40 shown in FIG. The shaft portion 42 of the temporary sealing plug 40 temporarily seals the first hole 21 , and the protrusion 41 a contacts the surface 4 c of the sealing plate 4 . As a result, it is possible to prevent the temporary sealing plug 40 from being excessively inserted into the inlet 20 . As a result, it is possible to prevent the electrolytic solution 30 adhering to the inner wall of the inlet 20 from spreading. When the head 41 of the temporary sealing plug 40 has a columnar shape, the protrusion 41a has, for example, a cylindrical shape. When the head 41 has a prismatic shape, the protrusion 41a has, for example, a prismatic shape. The height of the protrusion 41a is, for example, 0.05 mm or more, preferably 0.2 mm or more. According to one example, the height of the protrusion 41a is 5.0 mm or less.

Then, the battery is subjected to the gas generation process. In the gas generation step, gas is generated in the exterior member by heating the exterior member and/or by subjecting the battery to initial charging. The exterior member (battery) is heated, for example, at a temperature of 30° C. to 100° C. for 60 minutes to several days. Moisture that cannot be completely removed exists in the exterior member of the battery. This moisture is electrolyzed during the initial charge, generating hydrogen gas and the like. Instead of initial charging, the battery may be subjected to charge-discharge cycles.

After that, the battery is subjected to the gas release process. In the gas releasing step, at least part of the gas generated inside the exterior member in the gas generating step is released to the outside of the exterior member. Specifically, by removing the temporary sealing plug used for temporary sealing in the first sealing step from the first hole, the gas inside the exterior member is released to the outside of the exterior member through the inlet 20. . Before the gas release step, the pressure inside the exterior member is higher than the atmospheric pressure outside the exterior member. Therefore, by removing the temporary sealing plug from the first hole, part of the gas present in the exterior member is released to the outside of the exterior member. Note that the released gas contains the non-aqueous electrolyte. Therefore, the gas may be prevented from diffusing over a wide area by setting the atmosphere in which the gas is released to a negative pressure environment.

FIG. 17 is a cross-sectional view schematically showing the state around the injection port 20 after the gas generation process and before the gas discharge process. The electrolyte 30 adhering to the inner walls of the second holes 22 , for example, dries and crystallizes over time to change into crystals 31 of the electrolyte. At least some of the electrolyte crystals 31 are fixed or remain in the space defined by the second holes 22 . In other words, it is highly probable that the electrolyte crystals 31 do not adhere to the surface 4 c of the sealing plate 4 . Therefore, the problems described above with reference to FIG. 12, for example, can be resolved. That is, in the second sealing step following the gas release step, even if the sealing lid 14 is placed so as to cover the injection port 20, the crystals 31 of the electrolytic solution interfere with the adhesion between the sealing plate 4 and the sealing lid 14. can be obtained. Even if the electrolytic solution 30 adheres to the surface 4c of the sealing plate 4, it is possible to make it difficult for it to reach the welding location.

FIG. 18 is a cross-sectional view schematically showing an example of a state in which the temporary sealing plug 40 is removed from the first hole 21. FIG. After the gas release process, in the stage before the second sealing process, the crystals 31 of the electrolytic solution protrude from the surface 4c of the sealing plate 4 in the thickness direction as shown in FIG. may include The crystal 31a is formed, for example, by drying the electrolytic solution 30 adhering to the wall surface of the shaft portion 42 of the temporary sealing plug 40 in the first sealing step in the gas generating step.

As shown in FIG. 19, when the sealing lid 14 is placed on the surface 4c of the sealing plate 4 to seal the liquid injection port 20, the crystals 31 of the electrolytic solution are trapped in the space defined by the second hole 22. easy to be pushed into Therefore, it is possible to prevent the sealing lid 14 from floating due to the protruding crystal 31a. As a result, reliability of welding between the sealing plate 4 and the sealing lid 14 can be enhanced in the second sealing process (main sealing process) described later.

After the gas release process, the battery is subjected to the second sealing process. FIG. 20 is a cross-sectional view schematically showing an example of a state in which the injection port 20 is sealed through the second sealing process. In the second sealing step, for example, the sealing lid 14 is placed on the surface (outer wall) 4c of the sealing plate 4 so as to cover the liquid inlet 20, and the sealing lid 14 is placed against the sealing plate 4. Welding. The welding method is not particularly limited as long as the sealing plate 4 and the sealing lid 14 can be welded to hermetically seal the battery, but it is desirable to employ laser welding. The use of laser welding has the advantage of not requiring an additional material such as a sealing material and ensuring a high-strength hermeticity in a short period of time over a long period of time.

The welding point in the second sealing step is, for example, as shown in FIG. 6, outside the open end 22a of the second hole 22 and inside the outer edge of the sealing lid . Specifically, the in-plane direction of the surface 4 c of the sealing plate 4 is outside the open end 22 a of the second hole 22 and inside the outer edge of the sealing lid 14 . A welded portion 50 is formed by welding. The welded portion 50 is formed, for example, concentrically with the inlet 20 . The weld 50 may overlap the outer edge of the sealing lid 14 . The welded portion 50 may be provided in an annular shape, as shown in FIGS. 6 and 7, or may be provided in a rectangular annular shape. The shape of the welded portion 50 can be appropriately changed according to the shapes of the outer edges of the liquid inlet 20 and the sealing lid 14 . In the second sealing step, since the sealing plate 4 and the sealing lid 14 are connected by the welding portion 50, the battery is hermetically sealed.

The liquid injection port 20 sealed by the battery sealing method according to the embodiment is not limited to the mode shown in FIG. 7 and the like, and may have the mode shown in FIG. FIG. 21 is a cross-sectional view schematically showing a liquid injection port and its vicinity according to another example. In FIG. 21 , part of the sealing plate 4 has a convex portion protruding toward the interior of the exterior member 1 . The liquid injection port 20 penetrates the sealing plate 4 along the thickness direction at the position of the projection. The injection port 20 shown in FIG. 21 can be manufactured even when the thickness of the sealing plate 4 is relatively thin. Therefore, there is no need to excessively increase the thickness of the exterior member such as the sealing plate 4 for the purpose of forming the injection port. Therefore, in the battery provided with the injection port 20 of the embodiment shown in FIG. 21, the weight of the entire battery can be reduced and the manufacturing cost can be reduced. Further, according to the liquid injection port 20 shown in FIG. 21, the depth of the second hole 22 can be easily increased. When the depth of the second hole 22 is increased, it becomes difficult for the electrolytic solution that seeps out from the inside of the exterior member to reach the outer surface of the sealing plate 4 . As a result, there is a tendency that the yield can be further improved.

On the other hand, when manufacturing the injection port 20 described with reference to FIG. It is desirable to have a thickness greater than that. Therefore, when manufacturing the liquid injection port 20 shown in FIG. 7 and the like, it is desirable to increase the thickness of the sealing plate 4 compared to the case of manufacturing the liquid injection port 20 shown in FIG. However, the thickness of the sealing plate 4 should be such that it can withstand the mechanical load from the outside of the battery and the gas pressure generated inside the battery, and has the mechanical strength to hold the positive and negative terminals. The thickness is not particularly limited as long as the thickness is sufficient. Details of dimensions such as the depth and diameter of the first hole 21 and the second hole 22 will be described later with reference to FIG. 22 .

<Method for measuring the diameter of the first hole and the diameter of the second hole>
Here, a method for measuring the diameter of the first hole and the diameter of the second hole will be described. These diameters can be measured as follows using, for example, a scanning electron microscope (SEM). These diameters can also be measured using a microscope capable of optical length measurement or a microscope.

A part of the exterior member is cut out from the battery including the exterior member so as to include the injection port. The entire cut piece is then hardened using a resin such as epoxy resin. Next, the piece is cut using a rotating blade or the like across the injection port to obtain a cross section such as that shown in FIG. At this time, the direction in which the pieces are cut is, for example, the direction along the thickness direction of the sealing plate. The cutting position is such that the diameter of the circle defined by the open end 22a of the second hole 22 has the maximum length. The cross section thus obtained is observed with an SEM, and the diameter of the second hole 22 and the diameter of the first hole 21 are measured using the length measurement function of the SEM. The diameter of the second hole may be the diameter of the circle defined by the open end 22a of the second hole 22 at the position where the diameter of the circle has the maximum length. Also, the diameter of the first hole may be the diameter of the circle defined by the open end 21a of the first hole 21 at this cutting position.

Next, with reference to FIG. 22, the dimensions of the first hole 21, the second hole 22, etc. provided in the injection port 20 will be described. The schematic cross-sectional view shown in FIG. 22 shows the periphery of the injection port 20 according to an example cut according to the above-described measuring method.

Although the diameter 21d of the first hole 21 is not particularly limited, it is preferably in the range of 0.1 mm or more and 50 mm or less, for example, from the viewpoint of being able to pour the electrolytic solution in a short time. should be in the range of 1.0 mm or more and 10 mm or less. By setting the diameter 21d to 50 mm or less, the sealing of the first hole 21 using the temporary sealing plug can be made more reliable. That is, it is possible to improve the airtightness of the battery after temporary sealing in the first sealing step.

The diameter 22d of the second hole 22 is not particularly limited, but is, for example, within the range of 1.0 mm or more and 50 mm or less, preferably 1.5 mm or more and 15 mm or less. It is preferable that the diameter 22 d of the second hole 22 is determined in relation to the diameter 21 d of the first hole 21 . Specifically, the difference ΔD between the diameter 22d of the second hole 22 and the diameter 21d of the first hole 21 preferably satisfies Equation 1 below.
ΔD≧0.05 [mm] (1)

ΔD is more preferably 0.2 mm or more. When ΔD satisfies Formula 1 above, the volume of the hollow portion defined by the second hole 22 is sufficiently large. Therefore, in this case, it becomes easy to retain the electrolytic solution 30 within the space defined by the second holes 22 . As a result, proper sealing of the injection port 20 by the sealing lid 14 is facilitated, thereby improving the yield of the battery. From the viewpoint of keeping the electrolyte solution 30 within the space defined by the second hole 22, there is no problem if ΔD is large, but according to one example, the upper limit of ΔD is 10 mm.

The depth 21h of the first hole 21 is, for example, 0.05 mm or more and 10 mm or less, preferably 0.2 mm or more and 3 mm or less. If the depth 21h of the first hole 21 is excessively small, the mechanical strength of the first hole 21 is insufficient, and there is a possibility that temporary sealing in the first sealing step cannot be performed appropriately. The depth 22h of the second hole 22 is, for example, 0.01 mm or more and 10 mm or less, preferably 0.2 mm or more and 5 mm or less. If the depth 22h is too small, it may become difficult to keep the electrolytic solution 30 in the space defined by the second holes 22 .

The width 14w of the sealing lid 14 is, for example, within the range of 5 mm to 50 mm. The thickness of the sealing lid 14 is, for example, within the range of 0.05 mm to 10 mm in order to improve the sealing performance of the injection port 20 by laser welding. However, the width and thickness of the sealing lid 14 are not particularly limited as long as they are dimensions capable of sealing the injection port 20 in the second sealing step.

Although the dimensions of the battery (exterior member) according to the embodiment are not particularly limited, an example will be described with reference to FIG. 4, for example. The width of the cell parallel to the X-axis is, for example, in the range of 1 cm to 30 cm. The cell thickness parallel to the Y-axis is, for example, in the range of 1 cm to 30 cm. The cell height parallel to the Z-axis is, for example, in the range of 1 cm to 30 cm. In FIG. 4, the X-axis and the Y-axis are directions perpendicular to each other, and the Z-axis is a direction perpendicular to both the X-axis and the Y-axis.

Although the battery capacity is not particularly limited, it is, for example, within the range of 3Ah to 30Ah.

The shape of the exterior member is not limited to a rectangular shape as long as the liquid injection port according to the embodiment can be provided. The shape of the exterior member may be, for example, a flat type (thin type), a cylindrical type, a coin type, a button type, or the like. The exterior member can be appropriately selected according to the size of the battery and the application of the battery.

The wall thickness of the exterior member (including the sealing plate) may be, for example, 3.0 mm or less, 1.0 mm or less, or 0.5 mm or less. The wall thicknesses of the sealing plate 4 and bottomed prismatic container 3 are desirably adjusted so that they can withstand the mechanical load from the outside of the battery and the gas pressure generated inside the battery.

According to the first embodiment described above, a battery sealing method is provided. A battery sealing method is a method of sealing a battery including a positive electrode, a negative electrode, and an exterior member having a liquid inlet. The liquid inlet has a first hole facing the inner wall of the exterior member, and a second hole communicating with the first hole and facing the outer wall of the exterior member. The second hole has a larger diameter than the first hole. A battery sealing method includes a liquid filling step, a first sealing step, a gas generating step, a gas releasing step, and a second sealing step. The injection step is a step of injecting the electrolytic solution into the exterior member through the injection port. A 1st sealing process is a 1st sealing process which temporarily seals a 1st hole with a temporary sealing plug. The gas generation step is a step of generating gas in the exterior member by heating the exterior member and/or subjecting the battery to initial charging. The gas releasing step is a step of removing the temporary sealing plug and releasing the gas generated in the exterior member from the inlet. The second sealing step is a step of placing a sealing lid on the outer wall of the exterior member so as to cover the liquid inlet and welding the sealing lid to the exterior member.

According to the battery sealing method according to the present embodiment, the electrolyte can remain in the space defined by the second hole. There is a high probability that it can be sealed. Therefore, according to the method, an excellent yield can be achieved when manufacturing the battery.

(Second embodiment)
The battery manufacturing method according to the embodiment includes a step of sealing the battery by the battery sealing method according to the first embodiment. Therefore, according to the second embodiment, batteries can be manufactured with a high yield.

The batteries shown in FIGS. 1 to 7 are produced, for example, by the following method. First, the electrode group 2 is produced and housed in an exterior member. Specifically, after drying the produced electrode group 2 , the positive and negative electrode leads 8 and 10 are welded to the positive and negative

current collecting tabs

5 a and 6 a of the electrode group 2 . Next, the electrode guard 12 is attached to the positive and negative electrode

current collecting tabs

5 a and 6 a of the electrode group 2 , and the electrode guard 12 is fixed to the electrode group 2 with an insulating tape 13 . Next, after the positive and

negative terminals

9 and 11, the sealing plate 4, and the positive and

negative leads

8 and 10 are integrated by caulking, the sealing plate 4 is fixed to the opening of the exterior member 1 by welding. Thus, the electrode group 2 is housed inside the exterior member 1 . The positive and

negative leads

8 and 10, the electrode guard 12 and the insulating tape 13 are also housed inside the exterior member 1. As shown in FIG.

The liquid injection port 20 having the first hole 21 and the second hole 22 can be formed, for example, by pressing and/or punching a metal flat plate serving as the base of the sealing plate 4 . For pressing and/or punching, a mold can be selected that forms the first and

second holes

21 and 22 having desired dimensions and shapes.

Next, if necessary, water remaining in the exterior member 1 is removed from the liquid inlet of the sealing plate 4 . Thereafter, the battery is sealed by the battery sealing method according to the first embodiment described above. Specifically, the battery is sealed by a sealing method including a liquid injection step, a first sealing step, a gas generating step, a gas releasing step, and a second sealing step. Thus, the battery according to the embodiment can be manufactured.

The positive and negative electrode active materials, separator, non-aqueous electrolyte, exterior member, sealing plate, and electrode guard included in the battery will be explained.

Although the positive electrode active material is not particularly limited, for example, oxides or sulfides can be used. The positive electrode may contain one type of compound alone as a positive electrode active material, or may contain two or more types of compounds in combination. Examples of oxides and sulfides include Li or compounds capable of intercalating and deintercalating Li ions.

Examples of such compounds include manganese dioxide (MnO ₂ ), iron oxide, copper oxide, nickel oxide, and lithium manganese composite oxides (eg, Li _x Mn ₂ O ₄ or Li _x MnO ₂ ; 0<x≦1). , lithium nickel composite oxide (eg Li _x NiO ₂ ; 0 < x ≤ 1), lithium cobalt composite oxide (eg Li _x CoO ₂ ; 0 < x ≤ 1), lithium nickel cobalt composite oxide (eg Li _x Ni _1-y Co _y O ₂ ; 0<x≦1, 0<y<1), lithium manganese cobalt composite oxide (for example, Li _x _Mny Co _1-y O ₂ ; 0<x≦1, 0<y< 1) Lithium-manganese-nickel composite oxides having a spinel structure (e.g., Li _x Mn _2-y Ni _y O ₄ ; 0<x≦1, 0<y<2), lithium phosphorous oxides having an olivine structure (e.g., Li _xFePO4 ; 0<x≤1, _LixFe1 _- _yMnyPO4 ; 0<x≤1, ₀ <y _< 1, _LixCoPO4 _; 0<x≤1), iron sulfate ( _Fe2 ( _SO4 ) ₃ ), vanadium oxide ( _e.g. , _V2O5 ), and lithium-nickel-cobalt-manganese composite _oxide ( _LixNi1 _- _yzCoyMnzO2 ; 0< _x≤1 , 0<y <1, 0<z<1, y+z<1).

The negative electrode active material is not particularly limited, but at least one selected from the group consisting of carbon materials, silicon, silicon oxides and titanium-containing oxides can be used. Examples of carbon materials include artificial graphite, natural graphite, and spindle-shaped graphite obtained by compacting natural graphite and coating it with carbon.

Examples of titanium-containing oxides include lithium titanate having a ramsdellite structure (e.g. Li _2+y Ti ₃ O ₇ , 0≦y≦3), lithium titanate having a spinel structure (e.g. Li _4+x Ti ₅ O ₁₂ , 0≦x≦3), monoclinic titanium dioxide (TiO ₂ ), anatase titanium dioxide, rutile titanium dioxide, hollandite titanium composite oxide, monoclinic niobium titanium composite oxide, and rectangular Orthorhombic titanium-containing composite oxides can be mentioned.

The separator is not particularly limited, and may be, for example, a microporous membrane, woven fabric, non-woven fabric, or a laminate of the same or different materials among these. Materials for forming the separator include polyethylene, polypropylene, ethylene-propylene copolymer, ethylene-butene copolymer, cellulose, and the like. An inorganic solid electrolyte, an organic solid electrolyte, or the like may be used as the separator.

A non-aqueous electrolyte is prepared by dissolving an electrolyte (eg, lithium salt) in a non-aqueous solvent. Non-aqueous solvents include, for example, ethylene carbonate (EC), propylene carbonate (PC), butylene carbonate (BC), dimethyl carbonate (DMC), diethyl carbonate (DEC), ethylmethyl carbonate (EMC), γ-butyrolactone (γ- BL), sulfolane, acetonitrile, 1,2-dimethoxyethane, 1,3-dimethoxypropane, dimethyl ether, tetrahydrofuran (THF), 2-methyltetrahydrofuran, and the like. Non-aqueous solvents may be used alone or in combination of two or more. The electrolyte is, for example, lithium perchlorate (LiClO ₄ ), lithium hexafluorophosphate (LiPF ₆ ), lithium tetrafluoroborate (LiBF ₄ ), lithium arsenic hexafluoride (LiAsF ₆ ), trifluoromethanesulfonic acid Lithium salts such as lithium (LiCF ₃ SO ₃ ) may be mentioned. The electrolytes may be used alone or in combination of two or more. The amount of the electrolyte dissolved in the non-aqueous solvent is preferably 0.2 mol/L to 3 mol/L. If the electrolyte concentration is too low, sufficient ionic conductivity may not be obtained. On the other hand, if it is too high, it may not dissolve completely in the electrolytic solution.

For example, aluminum, aluminum alloy, iron (Fe), nickel (Ni) plated iron, stainless steel (SUS), etc. can be used as materials for the exterior member and the sealing plate. When the positive and

negative terminals

9 and 11 are made of aluminum or an aluminum alloy, the positive and

negative leads

8 and 10 can be made of aluminum or an aluminum alloy.

As the resin used for the electrode guard, any resin can be used as long as it is resistant to corrosion by the electrolytic solution. Examples include polyethylene, polypropylene, ethylene vinyl acetate copolymer, ethylene vinyl acetate alcohol copolymer, Ethylene-acrylic acid copolymer, ethylene-ethyl acrylate copolymer, ethylene-methyl acrylate copolymer, ethylene methacrylic acrylate copolymer, ethylene-methyl methacrylic acid copolymer, ionomer, polyacrylonitrile, polyvinylidene chloride, poly Tetrafluoroethylene, polychlorotrifluoroethylene, polyphenylene ether, polyethylene terephthalate, polytetrafluoroethylene, etc. can be used, and the above resins may be used singly or in combination. may be used as Among them, it is preferable to use polypropylene or polyethylene.

The battery manufacturing method according to the second embodiment includes a step of sealing the battery by the battery sealing method according to the first embodiment. Therefore, according to the battery manufacturing method according to the second embodiment, batteries can be manufactured with excellent yield.

(Third Embodiment)
According to a third embodiment, a battery is provided. A battery includes an exterior member having a liquid inlet and a sealing lid, and an electrode group housed in the exterior member and having a positive electrode, a negative electrode, and a separator. The liquid inlet has a first hole facing the inner wall of the exterior member, and a second hole communicating with the first hole and facing the outer wall of the exterior member. The second hole has a larger diameter than the first hole. The sealing lid is welded to the outer wall of the exterior member to seal the injection port.

The battery according to this embodiment is obtained through, for example, the battery sealing method according to the first embodiment. The configuration of the battery according to one example is as described with reference to FIGS. 1 to 7 in the first embodiment. Moreover, as for the material of each member included in the battery, for example, those described in the second embodiment can be used.

In the battery according to this embodiment, the liquid inlet has the first hole and the second hole. As described above, the diameter of the second hole is larger than the diameter of the first hole. Therefore, in the space defined by the second hole, for example, the electrolytic solution that seeps out from the interior of the exterior member during the manufacturing process of the battery can remain. Therefore, in the main sealing step (second sealing step), welding can be performed in a state of high adhesion between the sealing lid and the periphery of the liquid inlet of the exterior member. Therefore, in the obtained battery, the sealability of the injection port by the sealing lid is excellent.

Since the liquid injection port has the first hole and the second hole, even if a plurality of batteries according to the embodiment are manufactured, it is highly likely that a battery with high airtightness can be obtained. That is, the battery according to the third embodiment can achieve high yield.

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

DESCRIPTION OF SYMBOLS 1... Exterior member, 2... Electrode group, 3... Container, 4... Sealing plate, 5... Positive electrode, 5a... Positive electrode collector tab, 5b... Positive electrode active material containing layer, 6... Negative electrode, 6a... Negative electrode collector tab, 6b Negative electrode active material-containing layer 7 Separator 9 Positive electrode terminal 11 Negative electrode terminal 12 Electrode guard 13 Insulating tape 14 Sealing lid 16 Insulating plate 17 Insulating gasket 20 Note Liquid port 21... First hole 21a... First hole opening end 22... Second hole 22a... Second hole opening end 30... Electrolyte solution 31... Crystals of electrolyte solution 40... Temporary sealing plug , 41... Head, 42... Shaft part, 50... Welding part.

Claims

A method for sealing a battery comprising a positive electrode, a negative electrode, and an exterior member having an injection port, comprising:
The injection port includes a first hole facing the inner wall of the exterior member,
a second hole communicating with the first hole and facing an outer wall of the exterior member;
The second hole has a larger diameter than the first hole,
The method for sealing the battery includes:
an injection step of injecting an electrolytic solution into the exterior member through the injection port;
a first sealing step of temporarily sealing the first hole with a temporary sealing plug;
a gas generation step of generating gas in the exterior member by heating the exterior member and/or subjecting the battery to initial charging;
a gas release step of removing the temporary sealing plug and releasing the gas generated in the exterior member from the inlet;
and a second sealing step of placing a sealing lid on the outer wall of the exterior member so as to cover the liquid inlet and welding the sealing lid to the exterior member.
A part of the exterior member has a convex portion protruding toward the inside of the exterior member,
2. The method of sealing a battery according to claim 1, wherein the liquid injection port penetrates the exterior member along the thickness direction thereof at the position of the projection.
The temporary sealing plug includes a shaft portion inserted into the first hole and a head portion connected to the shaft portion,
3. In the battery temporarily sealed in the first sealing step, a gap is provided between the head portion of the temporary sealing plug and the outer wall of the exterior member. The method for sealing the battery according to .
The battery sealing method according to claim 3, wherein the distance between the head of the temporary sealing plug and the outer wall of the exterior member is at least 0.05 mm or more.
The battery sealing method according to any one of claims 1 to 4, wherein the diameter of the second hole continuously decreases from the outer wall side of the exterior member to the first hole.
The battery sealing method according to any one of claims 1 to 5, wherein the difference ΔD between the diameter of the second hole and the diameter of the first hole satisfies Equation 1 below.
ΔD≧0.05 [mm] (1)
A step of housing an electrode group including the positive electrode, the negative electrode and a separator in the exterior member;
A method for manufacturing a battery, comprising a step of sealing the battery by the battery sealing method according to any one of claims 1 to 6.
an exterior member including a liquid inlet and a sealing lid;
A battery that is accommodated in the exterior member and includes an electrode group including a positive electrode, a negative electrode, and a separator,
The injection port includes a first hole facing the inner wall of the exterior member,
a second hole communicating with the first hole and facing an outer wall of the exterior member;
The second hole has a larger diameter than the first hole,
The battery in which the sealing lid is welded to the outer wall of the exterior member to seal the injection port.
A part of the exterior member has a convex portion protruding toward the inside of the exterior member,
9. The battery according to claim 8, wherein the injection port penetrates the exterior member along the thickness direction thereof at the position of the projection.