JP7411925B2 - Manufacturing method of sealed battery with terminal and sealed battery with terminal - Google Patents

Description

The present invention relates to a method for manufacturing a sealed battery with a terminal and a sealed battery with a terminal.

In sealed batteries such as consumer alkaline batteries and industrial lithium primary batteries, terminal members (external terminals or lead terminals) are often attached by welding in order to make electrical contact with equipment. For example, an external terminal (exterior cap) is attached to the internal current collector of an alkaline dry battery. In addition, a lead terminal is attached to a lithium primary battery or the like for connection to a device board by soldering. Patent Document 1 proposes providing a lead terminal with an easily breakable portion for the purpose of improving workability during disposal of a battery with a terminal.

On the other hand, due to future social trends, there are demands for batteries to have longer expected lifespans (for example, from 10 years to 20 years) and higher capacities. In order to meet the above requirements, a battery (for example, Patent Document 2) that employs a rivet/washer structure in the sealing part and reduces the volume occupied by the gasket is advantageous.

Japanese Patent Application Publication No. 2003-115292 Japanese Patent Application Publication No. 2016-105374

In order to increase the capacity of batteries, increasing the energy density or increasing the size of the battery (increasing the height or increasing the diameter) is being considered, and in this case, from the perspective of ensuring battery reliability, the welding strength of the terminals must be increased. becomes important. If the welding conditions are made stricter in order to increase the welding strength, the gasket will be deformed due to the effects of heat during welding, and the sealing performance of the battery will deteriorate.

One aspect of the present invention includes a shaft portion having a hollow cylindrical portion on a first end side, and the shaft portion continuous to a second end portion on the opposite side of the first end portion of the shaft portion. A first step of preparing a rivet having a locking portion having a larger diameter than that of the first step, and preparing a sealing plate having a through hole into which the rivet is installed and a gasket for ensuring insulation from the rivet. a second step of inserting the shaft into the through hole of the sealing plate and compressing and deforming the rivet in the axial direction of the shaft, thereby removing the rivet from the hollow part of the cylindrical portion; a third step of forming a ring-shaped diameter-expanding deformation portion having a recessed portion; arranging a terminal member in the diameter-expanding deformation portion so as to cover the recess; and connecting the terminal member and the diameter-expanding deformation portion; The present invention relates to a method for manufacturing a sealed battery with a terminal, including a fourth step of joining the joint surfaces around the recessed portion by a welding method.

Another aspect of the present invention includes a power generation element, a case that accommodates the power generation element, a sealing plate that seals an opening of the case and has a through hole, and a power generation element that is inserted into the through hole. The rivet terminal includes a rivet terminal attached through a gasket and a terminal member connected to the rivet terminal. a diameter deforming portion; and a locking portion having a diameter larger than the shaft portion and connected to a second end portion of the shaft portion opposite to the first end portion, the diameter expanding deformation portion is ring-shaped with a recessed portion in the center, the terminal member is disposed in the diameter-expanding deformation portion so as to cover the recessed portion, and the terminal member and the diameter-expanding deformation portion are connected to each other in the recessed portion. This invention relates to a sealed battery with a terminal that is joined at the surrounding joint surfaces.

According to the present invention, in welding a terminal member and a sealed battery, it is possible to ensure necessary welding strength while suppressing deterioration in sealing performance of the battery due to deterioration of the gasket due to heat during welding.

It is a figure which shows typically the state at the time of welding the diameter expansion deformation part of a rivet and a terminal member in the 4th process of the manufacturing method of the sealed battery with a terminal of this invention. FIG. 7 is a cross-sectional view of a main part showing an example of a state in which a rivet shaft is inserted into a through hole of a sealing plate in a third step of a method for manufacturing a sealed battery with a terminal according to an embodiment of the present invention. FIG. 7 is a cross-sectional view of a main part showing an example of a state in which a diameter-expanding deformation portion of a rivet and a terminal member are joined in a fourth step of the method for manufacturing a sealed battery with a terminal according to an embodiment of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic vertical cross-sectional front view of a portion of a sealed battery with terminals according to an embodiment of the present invention. FIG. 3 is a diagram schematically showing a state in which a diameter-expanding deformation portion of a rivet and a terminal member are welded together in a conventional method for manufacturing a sealed battery with a terminal.

[Method for manufacturing sealed battery with terminal]
A method for manufacturing a sealed battery with a terminal according to an embodiment of the present invention includes a first step of preparing a rivet, and a sealing plate having a through hole into which the rivet is installed and a gasket for ensuring insulation from the rivet. a second step of preparing. The rivet includes a shaft portion having a hollow cylindrical portion on the first end side, and a lock having a diameter larger than the shaft portion connected to the second end portion on the opposite side of the first end portion of the shaft portion. It has a section and a.

Further, the above manufacturing method includes a third step of crimping the rivet to the sealing plate, and a fourth step of welding the crimped rivet and the terminal member. In the third step, the shaft is inserted into the through hole of the sealing plate, and the rivet is compressed and deformed in the axial direction of the shaft to form a ring shape having a recessed part originating from a hollow part of the cylindrical part. A diameter-expanding deformation portion is formed. In the third step, a sealing plate equipped with a rivet (hereinafter also referred to as a rivet terminal) in which a diameter-expanding deformation portion is formed is obtained. The diameter-expanding deformation portion is formed by crushing a portion of the cylindrical portion. The surface around the concave portion in the diameter-expanding deformation portion becomes the terminal surface of the sealed battery and is used for joining with the terminal member. In the fourth step, the terminal member is placed in the diameter-expanding deformation portion so as to cover the recess, and the terminal member and the diameter-expanding deformation portion are joined by a welding method at the joint surfaces around the recess.

Hereinafter, a welding process for welding a terminal member to a diameter-expanding deformation portion having no recessed portion in a conventional method for manufacturing a sealed battery with a terminal will be described with reference to FIG. FIG. 5 is a diagram schematically showing a state in which a diameter-expanding deformation portion having no recessed portion and a terminal member are welded together. Arrows in FIG. 5 indicate heat transfer.

As shown in FIG. 5, the metal rivet terminal 21 is attached to the sealing plate 7 via the gasket 9. The rivet terminal 21 includes a shaft portion 12, a diameter-expanding deformation portion 23 connected to a first end of the shaft portion 12, and a second end connected to the shaft portion 12 at a second end opposite to the first end. The locking portion 4 has a diameter larger than that of the shaft portion 12. The diameter-expanding deformation portion 23 has a disc shape without a depression in the center.

In the welding process, the terminal member 17 and the enlarged diameter portion 23 are welded together at the joint surface 28 . Specifically, as shown in FIG. 5, the terminal member 17 is placed on the diameter-expanding deformation portion 23, and heat is supplied to the welding location 29. At this time, since the diameter-expanding deformation portion 23 does not have a recessed portion, the heat supplied to the welding location 29 is likely to widely diffuse to the center and peripheral portions of the rivet terminal 21. For this reason, it is difficult to efficiently supply heat to the welding location 29, and the amount of heat supplied to the welding location 29 increases in order to obtain the necessary welding strength. As the amount of heat supplied to the welding location 29 increases, the amount of heat diffused to the peripheral portion of the rivet terminal 21 (on the side of the gasket 9) increases, making the gasket 9 more susceptible to the effects of heat during welding, and causing the gasket 9 to deteriorate.

Hereinafter, the fourth step of the method for manufacturing a sealed battery with terminals according to an embodiment of the present invention will be described with reference to FIG. 1. FIG. 1 is a diagram schematically showing a state during welding of a diameter-expanding deformation portion having a recessed portion formed in the third step and a terminal member. Arrows in FIG. 1 indicate heat transfer.

As shown in FIG. 1, a metal rivet terminal 11 is attached to a sealing plate 7 via a gasket 9. The rivet terminal 11 includes a ring-shaped diameter-expanding deformation portion 13 having a recessed portion 15 in the center. Other than the above, the rivet terminal 11 has the same structure as the rivet terminal 21.

In the fourth step, the terminal member 17 and the diameter-expanding deformation portion 13 are welded together at the joint surface 18 around the recess 15. Specifically, as shown in FIG. 1, the terminal member 17 is placed in the diameter-expanding deformation portion 13 so as to cover the recessed portion 15, and heat is supplied to the welding location 19. At this time, the recessed portion 15 formed in the third step suppresses the diffusion (heat radiation) of the heat supplied to the welding location 19 to the center of the rivet terminal 11 . Thereby, heat is efficiently supplied to the welding location 19, and the amount of heat supplied to the welding location 19 can be reduced in order to obtain the necessary welding strength. By reducing the amount of heat supplied to the welding location 19, the amount of heat diffused to the peripheral portion of the rivet terminal 11 (on the side of the gasket 9) is reduced, and deterioration of the gasket 9 due to heat during welding is suppressed.

The above manufacturing method may further include a sealing step of arranging a sealing plate equipped with a rivet terminal in the opening of the case housing the power generation element. The fourth step is usually performed after the sealing step, but if the terminal member is an external terminal, it may be performed before the sealing step.

In a cross section including the axis of the rivet shaft (hereinafter also referred to as cross section S), the recess preferably has a tapered bottom. In this case, the mechanical strength of the rivet is easily ensured, and the reliability of the rivet caulking process in the third step is improved. Examples of the tapered shape include a V-shape and a U-shape. The bottom of the recess may be rectangular.

In the fourth step, when the rivet is seen from the axial direction of the shaft, a plurality of Preferably, the points are spot welded. The welding may be performed at a plurality of locations at intervals, or may be welded in a linear manner. In the fourth step, it is more preferable to spot weld a plurality of locations at equal intervals on a circumference centered on the axis of the shaft in region A of the joint surface. In this case, deterioration of the gasket due to heat during welding is easily suppressed, and the reliability of joining the terminal member and the diameter-expanding deformation portion is further improved.

The ratio of the opening diameter D2 (mm) of the hollow part to the diameter D1 (mm) of the shaft part: D2/D1 is preferably 0.3 or more and less than 1, more preferably 0.3 or more and 0.7. It is as follows. When D2/D1 is less than 1, a ring-shaped region A is formed at the bonding surface. When D2/D1 is 0.3 or more, sufficient recessed portions are ensured while ensuring welding strength, and deterioration of the gasket due to heat during welding is easily suppressed. When D2/D1 is 0.7 or less, a sufficient welding area in area A is ensured.

The shape of the opening of the recessed portion may be circular, a polygon such as a triangle, a quadrangle, or a pentagon, or another special shape such as a star shape. When the shape of the opening of the recess is circular, the center may coincide with the axis of the shaft, or may be slightly shifted from the axis. In addition, when the shape of the opening of the recess is not circular, the opening diameter of the recess is determined by selecting the point farthest from the axis of the shaft at the opening of the recess, and moving the axis of the shaft through the selected point. Refers to the diameter of a circle drawn with the center at.

As the welding method, for example, a laser welding method or a resistance welding method is used.
The terminal member is, for example, a lead terminal or an external terminal (exterior cap) for electrically connecting the sealed battery and the electronic device. The exterior cap welded to the sealed battery is, for example, pressed into contact with a terminal of an electronic device. The strip-shaped lead terminals welded to the sealed battery are connected to the circuit board of the device by, for example, soldering. Alternatively, the lead wire may be connected to a lead terminal welded to the sealed battery, and the lead wire may be connected to a circuit board of the device using a connector disposed at the tip of the lead wire.

Examples of the material of the rivet terminal include stainless steel, copper, brass, and aluminum. Examples of the stainless steel include austenitic stainless steels such as SUS304, SUS305, and SUS316, and ferritic stainless steels such as SUS430 and SUS444. For example, a nickel-plated steel plate is used as the exterior cap. For example, a stainless steel plate with solder at the tip is used for the strip-shaped lead terminal.

Hereinafter, an example of a state in which the shaft portion of the rivet is inserted into the through hole of the sealing plate in the third step will be described with reference to FIG. 2. FIG. 2 shows a cross section S of a state where the shaft portion of the rivet is inserted into the through hole of the sealing plate, and shows a state before the rivet is crimped onto the sealing plate.

The rivet 1 includes a shaft portion 2 having a hollow cylindrical portion 3 on a first end side, and a shaft portion 2 connected to a second end portion on the opposite side of the first end portion of the shaft portion 2. The locking portion 4 has a large diameter.

The cylindrical portion 3 has a region P1 having a substantially constant wall thickness on the first end side, and a region P2 where the wall thickness increases toward the bottom portion on the second end side. The hollow part 5 of the cylindrical part 3 has a V-shaped bottom part 6 formed by the region P2. The thickness of the region P1 of the cylindrical portion 3 is, for example, 0.2 mm or more and 1.0 mm or less.

The sealing plate 7 has a through hole 8 in the center, and the shaft portion 2 is inserted into the through hole 8. The rivet 1 is locked to the sealing plate 7 by the locking portion 4 . The thickness of the sealing plate 7 is, for example, 0.1 mm or more and 0.5 mm or less. An insulating gasket 9 is interposed between the sealing plate 7 and the rivet 1 (shaft portion 2 and locking portion 4). A portion 9a of the gasket 9 is arranged to cover the shaft portion 2.

Hereinafter, in the fourth step, an example of a state in which the diameter-expanding deformation portion of the rivet formed in the third step and the terminal member are joined will be described with reference to FIG. 3. FIG. 3 shows a cross section S in which the diameter-expanding deformation portion and the terminal member are joined.

The rivet terminal 11 is formed by compressing and deforming the rivet 1 in the axial direction of the shaft 2 while the shaft 2 is inserted into the through hole 8 of the sealing plate 7 . That is, the rivet terminal 11 includes a shaft portion 12 originating from a part of the shaft portion 2 in FIG. It has a locking part 4 having a diameter larger than the shaft part connected to the second end opposite to the first end. The enlarged diameter deformed part 13 is formed by crushing a part of the cylindrical part 3 in FIG. It has a recessed part 15. A portion 9a of the gasket 9 is bent toward the sealing plate 7 as the diameter-expanding deformation portion 13 is formed, and insulates the diameter-expansion deformation portion 13 and the sealing plate 7.

A terminal member 17 is disposed on the diameter-expanding deformation portion 13 so as to cover the recessed portion 15 . The terminal member 17 and the diameter-expanding deformation portion 13 are joined at a joining surface 18 around the recessed portion 15 by a welding method.

The ratio of the opening diameter D2 (mm) of the hollow part 15 to the diameter D1 (mm) of the shaft part 12: D2/D1 is preferably 0.3 or more and less than 1, more preferably 0.3 or more and 0. .7 or less. When the diameter D1 of the shaft portion 12 is, for example, 4 mm or more and 6 mm or less, the opening diameter D2 of the recessed portion 15 is, for example, 1.5 mm or more and 4.0 mm or less.

In the cross section S, the tapered shape of the bottom of the recess 15 is V-shaped. From the viewpoint of ensuring reliability in crimping the rivet, the angle θ formed by the V-shape may be 120° or more, or may be 120° or more and 170° or less. The tapered shape of the bottom of the recessed portion 15 is not limited to a V-shape, but may be a U-shape or the like.

The depth T of the recessed portion 15 is desirably smaller than the distance L between the sealing plate 7 and the joint surface 18 in the axial direction of the shaft portion 12 . Thereby, even if the angle θ formed by the V-shape at the bottom of the recess is 120° or more, it is easy to adjust D2 appropriately and it is easy to secure the welding area of area A. The depth T of the recessed portion 15 is, for example, 0.05 mm or more and 1.25 mm or less, preferably 0.07 mm or more and 1.15 mm or less. Note that the depth T of the recessed portion 15 means the maximum depth of the recessed portion 15 in the axial direction of the shaft portion 12. Further, the volume of the recessed portion 15 is preferably, for example, 0.04 mm ³ or more and 4.80 mm ³ or less.

On the joint surface 18, four welding points 19 are provided at equal intervals on a circumference having a diameter D3 (mm) centered on the axis of the shaft portion 12. There may be a plurality of welding locations 19 other than four. As shown in FIG. 3, it is preferable to satisfy D2<D3<D1. From the viewpoint of suppressing deterioration of the gasket due to heat during welding, the ratio of D2 to D3: D2/D3 is preferably 0.65 or more and less than 1, more preferably 0.75 or more and less than 1.

The diameter-expanding deformation portion 13 has a ring-shaped region that comes into close contact with the gasket 9. From the viewpoint of suppressing deterioration of the gasket due to heat during welding, the outer diameter D5 (mm) of the ring-shaped region where the diameter expansion deformation portion 13 and the gasket 9 are in close contact with the diameter D4 (mm) of the through hole 8 of the sealing plate 7. The ratio: D5/D4 is preferably 1.5 or less, more preferably 1 or less.

The ratio of the outer diameter D6 (mm) of the diameter-expanding deformable portion 13 to the diameter D1 (mm) of the shaft portion 12: D6/D1 is preferably 1.25 or more and 2 or less. When D6/D1 is 1.25 or more, it is easy to appropriately adjust the contact area between the diameter-expanding deformation portion and the gasket, and the sealing performance of the battery is easily improved. When D6/D1 is 2 or less, it is easy to appropriately adjust the thickness of the diameter-expanding deformation portion, and the sealing performance of the battery is easily improved. Further, when D6/D1 is within the above range, heat is likely to be appropriately diffused from the welding location to the peripheral edge of the rivet terminal, and the influence of heat on the gasket is likely to be reduced.

[Sealed battery with terminal]
A sealed battery with a terminal according to an embodiment of the present invention includes a power generation element, a case that accommodates the power generation element, a sealing plate that seals an opening of the case and has a through hole, and a sealing plate that is inserted into the through hole. The device includes a rivet terminal attached to a plate via a gasket, and a terminal member connected to the rivet terminal.

The rivet terminal includes a shaft, a diameter-expanding deformation portion connected to a first end of the shaft, and a shaft connected to a second end opposite to the first end of the shaft. The locking portion also has a large diameter locking portion. The diameter-expanding deformation part is ring-shaped with a recessed part in the center, and the terminal member is arranged in the diameter-expanding deformation part so as to cover the recessed part. Bonded at the bonding surface.

Examples of sealed batteries include lithium primary batteries, alkaline dry batteries, lithium ion secondary batteries, nickel-metal hydride secondary batteries, and the like. The power generation element may include, for example, a positive electrode, a negative electrode, and an electrolyte, one of the positive and negative electrodes may be electrically connected to the rivet terminal, and the other of the positive and negative electrodes may be electrically connected to the case. . The power generation element may be a laminated electrode body in which a sheet-shaped positive electrode and a sheet-shaped negative electrode are laminated with a separator in between, or a wound-type electrode in which a sheet-shaped positive electrode and a sheet-shaped negative electrode are wound with a separator in between. It can be your body. Further, the power generation element may have an inside-out structure including a cylindrical positive electrode and a gelled negative electrode disposed within a hollow portion of the positive electrode with a separator interposed therebetween. A rolled negative electrode may be arranged instead of the gel negative electrode. Furthermore, welding of the diameter-expanding deformation portion having the recessed portion of the rivet terminal and the terminal member can also be applied to electrochemical elements such as electric double layer capacitors and capacitors.

Hereinafter, a lithium primary battery with a terminal will be described as an example of a sealed battery with a terminal, with reference to FIG. 4. FIG. 4 is a front view schematically showing a part of a sealed battery with a terminal according to an embodiment of the present invention in longitudinal section.

The lithium primary battery 30 includes a cylindrical battery can 100 with a bottom, a wound electrode body 200 housed in the battery can 100, and a sealing unit that closes the opening of the battery can 100. The sealing unit includes a sealing plate 310, a rivet terminal 320, and an insulating gasket 330 disposed between the sealing plate 310 and the rivet terminal 320. A lead terminal 340 is connected to the rivet terminal 320. Further, another lead terminal 350 is connected to the polarity side opposite to that of the rivet terminal 320 (at the bottom of the battery can 100).

The peripheral edge of the sealing plate 310 is fixed near the opening of the battery can 100 by welding. A through hole is formed in the center of the sealing plate 310, and the rivet terminal 320 is inserted into the through hole and attached to the sealing plate 310 via a gasket 330.

The rivet terminal 320 includes a shaft portion 321, a diameter expanding deformation portion 322 connected to a first end of the shaft portion 321, and a second end of the shaft portion 321 opposite to the first end. and a locking portion 323 having a larger diameter than the shaft portion 321. The diameter-expanding deformation portion 322 is ring-shaped with a recessed portion 324 in the center. The lead terminal 340 is placed on the enlarged diameter deformed part 322 so as to cover the recessed part 324, and the lead terminal 340 and the enlarged diameter deformed part 322 are joined by welding at the joint surface 325 around the recessed part 324. There is.

The battery can 100 and the sealing plate 310 are each made of, for example, iron, iron alloy (SUS, etc.), aluminum, aluminum alloy (aluminum alloy, etc. containing trace amounts of other metals such as manganese and copper), etc. Depending on the situation, it may be plated.

The electrode body 200 is configured by spirally winding a sheet-like positive electrode 201 and a sheet-like negative electrode 202 with a sheet-like separator 203 in between. One end of a first current collection wire 210 is connected to one of the positive electrode 201 and the negative electrode 202 (in the illustrated example, the negative electrode 202). The other end of the first current collector wire 210 is connected to a locking portion 323 of a rivet terminal 320 by welding or the like. One end of a second current collection wire 220 is connected to the other of the positive electrode 201 and the negative electrode 202 (in the illustrated example, the positive electrode 201). The other end of the second current collector wire 220 is connected to the inner surface of the battery can 100 by welding or the like.

The wound electrode body 200 is housed inside the battery can 100 along with a non-aqueous electrolyte (not shown). To prevent internal short circuits, an upper insulating plate 230A and a lower insulating plate 230B are arranged at the upper and lower parts of the electrode body 200, respectively.

In the illustrated example, a cylindrical lithium primary battery has been described, but the present embodiment is not limited to this case and can be applied to other sealed batteries. Further, the opening of the battery can may be sealed by caulking the peripheral edge of the sealing plate.

The constituent elements of the lithium primary battery will be further explained below.
(Negative electrode)
The negative electrode contains metallic lithium or an alloy of metallic lithium and lithium. Examples of the lithium alloy include Li--Al, Li--Sn, Li--Ni--Si, and Li--Pb. Among lithium alloys, Li--Al alloy is preferred from the viewpoint of potential and alloying composition with lithium. The content of metal elements other than lithium contained in the lithium alloy is preferably 0.05% by mass or more and 1.0% by mass or less based on the metal element alloyed with lithium. Note that the metallic lithium may contain less than 0.05% by mass of elements other than lithium.

As the sheet-shaped negative electrode, for example, a metallic lithium foil or a composite sheet containing metallic lithium and a lithium alloy is used. In the composite, the lithium alloy may be dispersed in the form of particles in metallic lithium. The sheet-like negative electrode can be formed, for example, by extruding metallic lithium or metallic lithium and a lithium alloy. The lithium alloy may be formed by attaching an Al lattice or the like to the surface of a metal lithium foil and alloying the surface layer of the metal lithium foil.

(positive electrode)
The positive electrode includes a positive electrode active material. As the positive electrode active material, any material used for positive electrodes of primary batteries and secondary batteries may be selected and used. For example, manganese dioxide, fluorinated graphite, iron sulfide, lithium manganate, etc. can be used. The positive electrode includes, for example, a positive electrode current collector and a positive electrode mixture layer supported on the positive electrode current collector and containing a positive electrode active material.

As the material of the positive electrode current collector, stainless steel, a metal material containing Al and/or Ti, etc. can be used. As the stainless steel, highly corrosion resistant ones such as SUS444 and SUS316 are preferable. The metal material containing Al and/or Ti may be an alloy. As the positive electrode current collector, for example, a sheet or a porous body is used. A metal foil or the like may be used as the positive electrode current collector. Furthermore, a metal mesh (or net), expanded metal, punched metal, or the like may be used as the porous positive electrode current collector.

In addition to the positive electrode active material, the positive electrode mixture constituting the positive electrode mixture layer may optionally contain a binder and/or a conductive agent. Examples of the binder include fluororesin, polyacrylonitrile, polyimide resin, acrylic resin, polyolefin resin, rubber-like polymer, and the like. Examples of the fluororesin include polytetrafluoroethylene and polyvinylidene fluoride. One type of binder may be used alone, or two or more types may be used in combination.

A carbon material is preferable as the conductive agent. Examples of the carbon material include carbon black (acetylene black, Ketjen black, etc.), carbon nanotubes, graphite, and the like. One type of conductive agent may be used alone, or two or more types may be used in combination. The conductive agent may be present between the positive electrode current collector and the positive electrode mixture layer.

The method for manufacturing the positive electrode is not particularly limited. The positive electrode can be obtained, for example, by attaching a positive electrode mixture to a positive electrode current collector. For example, the positive electrode mixture may be applied to a positive electrode current collector, or may be filled into a porous positive electrode current collector. Alternatively, the positive electrode mixture may be formed into a sheet and laminated so as to physically contact the positive electrode current collector. When producing a positive electrode, the positive electrode mixture is prepared in a paste-like or clay-like form using a dispersion medium (e.g., water and/or an organic medium) in addition to the constituent components of the positive electrode mixture, as necessary. May be used in At an appropriate stage of producing the positive electrode, drying may be performed as necessary, and compression (rolling, etc.) in the thickness direction of the positive electrode may be performed.

(Separator)
A porous sheet having ion permeability and insulation properties is used for the separator. Examples of porous sheets include microporous films, woven fabrics, and nonwoven fabrics. The separator may have a single layer structure or a multilayer structure. Examples of the multilayer separator include a separator including a plurality of layers having different materials and/or structures.

The material of the separator is not particularly limited, but may be a polymer material. Examples of polymeric materials include olefin resins (polyethylene, polypropylene, copolymers of ethylene and propylene, etc.), polyamide resins, polyimide resins (polyimide, polyamideimide, etc.), cellulose, polyphenylene sulfite (PPS), polytetrafluorocarbons, etc. Examples include oleoethylene (PTFE). The separator may contain additives as necessary. Examples of additives include inorganic fillers.

The thickness of the separator can be selected, for example, from a range of 10 μm or more and 200 μm or less. When the separator is composed of a microporous film, the thickness of the separator is, for example, 10 μm or more and 80 μm or less, preferably 20 μm or more and 70 μm or less.

(Non-aqueous electrolyte)
As the non-aqueous electrolyte, one having lithium ion conductivity is used. Such a nonaqueous electrolyte includes a nonaqueous solvent and a lithium salt as an electrolyte dissolved in the nonaqueous solvent. A non-aqueous electrolyte is prepared by dissolving a lithium salt in a non-aqueous solvent.

As the lithium salt, any salt used in the non-aqueous electrolyte of a lithium primary battery may be used without any particular limitation. Examples of the lithium salt include lithium borofluoride, lithium hexafluorophosphate, lithium trifluoromethanesulfonate, lithium bis(fluorosulfonyl)imide, lithium bis(trifluoromethylsulfonyl)imide, lithium perchlorate, and the like. One type of lithium salt may be used alone, or two or more types may be used in combination.

Examples of the nonaqueous solvent include, but are not limited to, esters (eg, carbonic acid esters, carboxylic acid esters such as γ-butyrolactone, etc.), and ethers (1,2-dimethoxyethane, etc.). Examples of carbonate esters include cyclic carbonates (propylene carbonate, ethylene carbonate, etc.), chain carbonates (diethyl carbonate, ethylmethyl carbonate, etc.), and the like. The non-aqueous solvents may be used alone or in combination of two or more.

The concentration of the lithium salt in the nonaqueous electrolyte is, for example, 0.1 mol/L or more and 3.5 mol/L or less.

The non-aqueous electrolyte may contain additives, if necessary. Examples of the additive include vinylene carbonate, fluoroethylene carbonate, vinyl ethyl carbonate, and the like. One type of additive may be used alone, or two or more types may be used in combination.

[Example]
EXAMPLES Hereinafter, the present invention will be specifically explained based on Examples and Comparative Examples, but the present invention is not limited to the following Examples.

《Example 1》
(1st step)
a shaft portion having a hollow cylindrical portion on the first end side; a locking portion having a diameter larger than the shaft portion connected to a second end portion on the opposite side of the first end portion of the shaft portion; A stainless steel rivet was prepared.

The rivet had a similar structure to rivet 1 shown in FIG. The diameter D1 of the shaft portion was 6 mm. The diameter of the locking portion was 10 mm. The length of the shaft portion in the axial direction was 4.0 mm. The axial length of the cylindrical portion was 2.5 mm. The cylindrical portion includes a region P1 having a constant thickness on the first end side, and a region P2 having a thickness increasing toward the bottom on the second end side. The thickness of the region P1 was set to 0.5 mm. The length of the region P1 in the axial direction was 2.0 mm. The length of the region P2 in the axial direction was 0.5 mm. A V-shaped bottom was formed in the hollow part of the cylindrical part by the region P2, and the V-shaped formation angle θ was 150°.

(Second process)
A stainless steel sealing plate was prepared, which had a through hole into which a rivet was attached, and a polypropylene gasket to ensure insulation from the rivet (second step). The sealing plate had the same structure as the sealing plate 7 shown in FIG. The thickness of the sealing plate was 0.4 mm. The diameter D4 of the through hole of the sealing plate was 7.0 mm.

(3rd step)
As shown in FIG. 2, the shaft portion was inserted into the through hole of the sealing plate. By compressing and deforming the rivet in the axial direction of the shaft part, a ring-shaped diameter-expanding deformation part having a recessed part originating from a hollow part of the cylindrical part was formed (third step). In this way, a sealing plate equipped with rivet terminals as shown in FIG. 3 was obtained.

The distance L between the joint surface of the diameter-expanding deformation portion with the terminal member and the sealing plate in the axial direction of the shaft portion was set to 0.83 mm. The outer diameter D5 of the ring-shaped contact area between the diameter-expanding deformation portion and the gasket was 6.6 mm. The outer diameter D6 of the diameter expanding portion was 9.0 mm. D6/D1 was 1.5.

In the third step, a recessed portion having a V-shaped bottom originating from the bottom of the hollow portion was formed. The opening diameter D2 of the recess was 1.0 mm. The depth T of the recessed portion was 0.13 mm. The V-shaped forming angle θ at the bottom of the recess was 150°. The volume V of the recessed portion was 0.03 mm ³ .

(4th step)
As shown in FIG. 3, the terminal member was placed in the diameter-expanding deformation portion so as to cover the recess, and the terminal member and the diameter-expanding deformation portion were joined by laser welding at the joint surfaces around the recess.

As the terminal member, a stainless steel strip-shaped lead terminal (length 20 mm, width 5 mm, thickness 0.15 mm) was used. In the fourth step, on the joint surface, spot welding was performed at four locations equally spaced on a circumference having a diameter D3 of 4.5 mm centered on the axis of the shaft portion. In the fourth step, the output of the laser irradiated to the joint surface was adjusted so that the welding strength determined by Evaluation 1, which will be described later, was 300 N, and the laser irradiation time was kept constant. Laser irradiation was performed one by one in sequence. Laser irradiation at four locations was performed under the same conditions.

《Examples 2 to 4》
By adjusting the shape and dimensions of the cylindrical part (hollow part) of the rivet prepared in the first step, the opening diameter D2, depth T, and bottom V-shaped formation angle θ of the recessed part to be formed in the third step are adjusted. and the volume V were set to the values shown in Table 1. The opening diameter D2 was adjusted by changing the axial length of the shaft portion 2 while keeping the axial lengths of the regions P1 and P2 of the cylindrical portion constant and the V-shaped forming angle θ. Except for the above, a sealing plate equipped with a rivet terminal was produced by the same method as in Example 1, and the diameter-expanding deformation portion of the rivet terminal and the terminal member were joined.

《Comparative example 1》
In the first step, a rivet having a cylindrical shaft portion and a locking portion having a diameter larger than the shaft portion and connected to one end of the shaft portion was prepared. In the third step, a disk-shaped diameter-expanding deformation portion having no recessed portion was formed. A sealing plate equipped with a rivet terminal was produced by the same method as in Example 1 except for the above.

The diameter-expanding deformation portion and the terminal member were joined by the same method as in Example 1, except that the terminal member was placed in the diameter-expanding deformation portion having no recessed portion.

The manufacturing methods (fourth step) of Examples 1 to 4 and Comparative Example 1 were evaluated as follows.
[Evaluation 1: Welding strength]
The sealing plate with the rivet terminal mounted thereon was fixed, and the portion of the terminal member other than the joint surface with the expansion deformation portion was bent in a direction perpendicular to the joint surface. The bent part was pulled until two of the four parts of the welded part on the bent part side were broken, and the maximum value of the force required at this time was determined as the welding strength.

[Evaluation 2: Heat amount]
Based on the output and irradiation time of the laser irradiated to one location on the joint surface, the amount of heat required for welding the four locations (the sum of the amount of heat at the four locations) was determined.

[Evaluation 3: Gasket temperature]
The maximum temperature of the gasket during welding was measured using a thermocouple.

Table 1 shows the evaluation results of the manufacturing methods of Examples 1 to 4 and Comparative Example 1.

In Examples 1 to 4, compared to Comparative Example 1, the diameter expansion deformation portion and the terminal member could be firmly joined with a smaller amount of heat, and the temperature rise of the gasket during welding was suppressed. Among them, in Examples 2 to 4 in which D2/D1 is 0.3 or more, the diameter expansion deformation part and the terminal member can be firmly joined with a smaller amount of heat, and the temperature rise of the gasket during welding is further suppressed. Ta.

《Examples 5 to 9》
The diameter D1 of the shaft portion of the rivet was 4.4 mm. The diameter D4 of the through hole of the sealing plate was 5.4 mm. The shape and dimensions of the cylindrical part (hollow part) of the rivet are adjusted, and the opening diameter D2, depth T, bottom V-shaped formation angle θ, and volume V of the recessed part formed in the third step are shown in the table. The values shown in 2 were used. In the fourth step, on the joint surface, spot welding was performed at four locations at equal intervals on the circumference of the diameter D3 centered on the axis of the shaft portion as shown in Table 2. The outer diameter D5 of the ring-shaped close contact region between the diameter-expanding deformation portion and the gasket was set to 5.0 mm. The distance L between the joint surface of the diameter-expanding deformable portion with the terminal member and the sealing plate in the axial direction of the shaft portion was 0.83 mm (Examples 5, 6, 8) or 1.3 mm (Examples 7, 9). ). The outer diameter D6 of the diameter expanding portion was 6.6 mm. D6/D1 was 1.5.

Except for the above, a sealing plate equipped with a rivet terminal was produced by the same method as in Example 1, and the diameter-expanding deformation portion of the rivet terminal and the terminal member were joined.

《Comparative example 2》
In the first step, a rivet having a cylindrical shaft portion and a locking portion having a diameter larger than the shaft portion and connected to one end of the shaft portion was prepared. In the third step, a disk-shaped diameter-expanding deformation portion having no recessed portion was formed. A sealing plate equipped with a rivet terminal was produced in the same manner as in Example 5 except for the above.

The diameter-expanding deformation portion and the terminal member were joined by the same method as in Example 5, except that the terminal member was placed in the diameter-expanding deformation portion having no recessed portion.

The above evaluations 1 to 3 were performed on the manufacturing methods (fourth step) of Examples 5 to 9 and Comparative Example 2. Table 2 shows the evaluation results of the manufacturing methods of Examples 5 to 9 and Comparative Example 2.

In Examples 5 to 9, compared to Comparative Example 2, it was possible to firmly join the diameter-expanding deformation portion and the terminal member with a smaller amount of heat, and the temperature rise of the gasket during welding was suppressed. Among them, in Examples 5 to 7, the temperature rise of the gasket during welding was further suppressed. In Examples 5 to 7, the opening diameter D2 is 1.5 mm or more and 4.0 mm or less, the V-shaped forming angle θ at the bottom of the recess is 120° or more and 170° or less, and the volume of the recess is V was 0.04 mm ³ or more and 4.82 mm ³ or less.

《Examples 10 to 12, Reference Example 13》
In the fourth step, the same method as in Example 3 was used, except that on the joint surface, four spots were spot welded at equal intervals on the circumference with a diameter D3 centered on the axis of the shaft part as shown in Table 3. A sealing plate equipped with a rivet terminal was prepared, and the expanded diameter portion of the rivet terminal and the terminal member were joined.

The above evaluations 1 to 3 were performed for the manufacturing methods (fourth step) of Examples 10 to 12 and Reference Example 13. Table 3 shows the evaluation results of the manufacturing methods of Examples 10 to 12 and Reference Example 13. Table 3 also shows the evaluation results of the manufacturing method of Example 3.

In Examples 10 to 12 , as in Example 3, the diameter expansion deformation portion and the terminal member could be firmly joined with a small amount of heat, and the temperature rise of the gasket during welding was suppressed. Among them, in Examples 3 and 10 to 11 in which D2/D3 is 0.65 or more, the diameter expansion deformation part and the terminal member can be firmly joined with a smaller amount of heat, and the temperature rise of the gasket during welding is further reduced. suppressed.

《Examples 14 to 18》
The diameter D1 of the shaft portion of the rivet was 5 mm. The diameter D4 of the through hole of the sealing plate was 6 mm. The opening diameter D2 of the recess formed in the third step was 2 mm. The depth T of the recessed portion was 0.27 mm. The V-shaped forming angle θ at the bottom of the recess was 150°. The volume V of the recessed portion was 0.14 mm ³ . In the fourth step, on the joint surface, spot welding was performed at four locations at equal intervals on a circumference having a diameter D3 of 3 mm centered on the axis of the shaft portion.

The outer diameter D5 of the ring-shaped close contact region between the diameter-expanding deformation portion and the gasket was set to the value shown in Table 4. The outer diameter D5 was adjusted in the third step by inserting the shaft into the through hole of the sealing plate and changing the compression force when compressing and deforming the rivet in the axial direction of the shaft. In Examples 14 to 18, the distance L between the joint surface of the diameter-expanding deformation portion with the terminal member and the sealing plate in the axial direction of the shaft portion was in the range of 0.75 mm to 0.9 mm. The outer diameter D6 of the diameter expansion change portion was in the range of 8.2 mm to 9.5 mm. D6/D1 ranged from 1.64 to 1.9.

Except for the above, a sealing plate equipped with a rivet terminal was produced by the same method as in Example 1, and the diameter-expanding deformation portion of the rivet terminal and the terminal member were joined.

Regarding the manufacturing methods (fourth step) of Examples 14 to 18, the above evaluations 1 to 3 were performed. Table 4 shows the evaluation results of the manufacturing methods of Examples 14 to 18.

In Examples 14 to 18, the enlarged diameter portion and the terminal member could be firmly joined with a small amount of heat, and the temperature rise of the gasket during welding was suppressed. Among them, in Examples 14 to 15 in which D5/D4 was 1 or less, the diameter expansion deformation part and the terminal member could be firmly joined with a smaller amount of heat, and the temperature rise of the gasket during welding was further suppressed.

The sealed battery with terminals according to the present invention is suitably used as a power source for various industrial and consumer devices.

1: Rivet, 2: Shaft, 3: Cylindrical part, 4: Locking part, 5: Hollow part, 6: Bottom, 7: Sealing plate, 8: Through hole, 9: Gasket, 9a: Part of gasket , 11, 21: Rivet terminal, 12: Shaft portion, 13, 23: Diameter expansion deformation portion, 15: Hollow portion, 17: Terminal member, 18, 28: Joint surface, 19, 29: Welding location, 30: Primary lithium Battery, 100: Battery can, 200: Electrode body, 201: Positive electrode, 202: Negative electrode, 203: Separator, 210: First current collecting wire, 220: Second current collecting wire, 230A: Upper insulating plate, 230B: Lower insulating Plate, 310: Sealing plate, 320: Rivet terminal, 321: Shaft, 322: Expanding diameter portion, 323: Locking portion, 324: Recessed portion, 325: Joint surface, 330: Gasket, 340, 350: Lead terminal

Claims (5)

A shaft portion having a hollow cylindrical portion on a first end side, and a lock having a diameter larger than the shaft portion connected to a second end portion of the shaft portion on the opposite side from the first end portion. a first step of preparing a rivet having a part;
a second step of preparing a sealing plate having a through hole into which the rivet is installed and a gasket for ensuring insulation from the rivet;
By inserting the shaft into the through hole of the sealing plate and compressing and deforming the rivet in the axial direction of the shaft, a ring having a recessed portion originating from a hollow part of the cylindrical portion. a third step of forming a diameter-expanding deformation portion of the shape;
a fourth step of arranging a terminal member in the diameter-expanding deformation portion so as to cover the recess portion, and joining the terminal member and the diameter-expansion deformation portion at a joint surface around the recess portion by a welding method; including;
A diameter D1 mm of the shaft portion, an opening diameter D2 mm of the recessed portion opening to the joint surface, and a distance D3 mm from the welding point of the diameter enlarged deformation portion with the terminal member on the joint surface to the center of the shaft portion. What is
When the volume V of the recessed portion is larger than 0.31 mm3, the relationship D2<D3<D1 is satisfied ^,
A method for manufacturing a sealed battery with a terminal , which satisfies the relationship D2<D3≦(5/6)×D1 when the volume V of the recessed portion is 0.31 mm ³ or less. 2. The method for manufacturing a sealed battery with a terminal according to claim 1, wherein the recess has a tapered bottom in a cross section including the axis of the shaft of the rivet. In the fourth step, when the rivet is viewed from the axial direction of the shaft, a plurality of spots are placed on the joining surface in a region inside the outer periphery of the shaft and outside the opening of the recess. weld,
The diameter D1mm of the shaft portion and the opening diameter D2mm of the recessed portion are expressed by the following relational expression:
0.3≦D2/D1< D3/D1
The method for manufacturing a sealed battery with a terminal according to claim 1 or 2, which satisfies the following. The sealed battery with a terminal according to claim 1, wherein the terminal member is a lead terminal for electrically connecting the sealed battery to an electronic device or an external terminal of the sealed battery. Production method. power generation element,
a case housing the power generation element;
a sealing plate that seals the opening of the case and has a through hole;
a rivet terminal inserted into the through hole and attached to the sealing plate via a gasket;
a terminal member connected to the rivet terminal,
The rivet terminal includes a shaft, a diameter expanding deformation portion connected to a first end of the shaft, and a second end of the shaft opposite to the first end. a locking portion having a larger diameter than the shaft portion;
The diameter expanding deformation portion is ring-shaped with a recessed portion in the center;
The terminal member is disposed in the diameter-expanding deformation portion so as to cover the recess, and the terminal member and the diameter-expansion deformation portion are joined at a joint surface around the recess ,
A diameter D1mm of the shaft portion, an opening diameter D2mm of the recessed portion opening to the joint surface, and a distance D3mm from the welding point of the diameter expansion deformation portion with the terminal member on the joint surface to the center of the shaft portion. What is
When the volume V of the recessed portion is larger than 0.31 mm ³ , the relationship D2<D3<D1 is satisfied,
A sealed battery with a terminal that satisfies the relationship D2<D3≦(5/6)×D1 when the volume V of the recessed portion is 0.31 mm ³ or less.

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