JPH0718346U - Sealed battery - Google Patents

Abstract

(57) [Summary] [Purpose] A battery that uses a sealing plate that does not have a folded portion has a sharp burr at the bottom of its opening end, and the sealing plate and gasket are galled during the battery assembly process, resulting in marked productivity. Was being lowered. The production of sharp burrs below the opening end is prevented to improve productivity. [Structure] By setting the clearance between the cutting die and the cutting punch at the time of final trimming in the pressing process, which is the process of processing the sealing plate, a uniform fracture surface is provided in the sealing plate trimming part, and sharp burrs downward. To prevent the occurrence of. According to this method, it is possible to reduce the galling in the coupling process of the sealing plate and the gasket in the battery assembly process and improve the productivity.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a sealed battery in which a power generating element is sealed by a battery case such as a coin type lithium battery, a button type air battery and a silver oxide battery, a sealing plate, and an insulating gasket.

[0002]

[Prior art]

 A conventional technique using a sealing plate having no folded portion will be described below with reference to the drawings by taking a manganese dioxide / lithium battery as an example. Figure 3 shows the structure of a conventional manganese dioxide / lithium battery.

As shown in FIG. 3, a positive electrode mixture obtained by press-molding a mixed powder of manganese dioxide, graphite, a binder and the like on the inner bottom surface of a battery case 31 which also functions as a positive electrode terminal made of a metal having a cylindrical shape with a bottom. 32 is arranged, the positive electrode mixture 32 is covered with the cup-shaped separator 33, and the positive electrode mixture 32 is impregnated with the organic electrolytic solution. A metal lithium 34 serving as a negative electrode is placed on the separator 33, and an insulating gasket 35 made of a resin having an L-shaped cross section is sandwiched between the openings of the battery case 31 to be swaged inward to also serve as a reverse dish-shaped negative electrode terminal. The sealing plate 36 is sealed.

Conventionally, as described in Japanese Utility Model Publication No. 57-29250, the shape of the sealing plate has been provided with a folded portion 41 at its periphery as shown in FIG. 4 (a). Market demands for lower prices have increased, and as shown in FIG. 4 (b), a sealing plate having no folded portion on the periphery has been used. However, in the sealing plate having no folded portion as described above, a sharp burr 42 is generated downward at the opening end during the trimming of the press working which is the manufacturing process. An enlarged cross-sectional view of the portion a in FIG. 4 (b) is shown in FIG. 4 (c). If a sealing plate having such a sharp downward burr is used, there is a disadvantage that the opening end of the sealing plate bites the upper part of the insulating gasket during the battery construction process, leading to the occurrence of defects and reducing productivity. It was

[0005]

[Problems to be solved by the device]

 As described above, in the conventional structure, the sealing plate and the insulating gasket are galled in the battery manufacturing process, resulting in a significant decrease in productivity.

The present invention solves the above-mentioned problems, and an object of the present invention is to prevent galling with an insulating gasket in a battery manufacturing process and improve productivity even when a sealing plate having no folded portion is used. To do.

[0007]

[Means for Solving the Problems]

 The inventors of the present invention have eliminated sharp burrs by increasing the clearance between the trimming die and the punch to prevent sharp burrs downward when trimming in the press working process, which is the above-mentioned sealing plate manufacturing process. By using a sealing plate that has a uniform cross-section around the open end and has a shape that does not have a seal, it is possible to prevent galling of the sealing plate and the insulating gasket.

[0008]

[Action]

 If the clearance at the time of trimming in the pressing process is set to 0, all the cut surfaces will be sheared surfaces and there will be no burr, but it is impossible to set the clearance to 0 due to the error of the press machine and the wear of the mold. In reality, a small clearance is set. If this clearance is small, the area of the shear plane at the cut surface will be large, and sharp burrs will occur at the slight fracture surface. However, if this clearance is increased, the area of the shear plane becomes smaller and the area of the fracture surface becomes larger. When the area of the fracture surface becomes large, the cut surface becomes dirty, but sharp burrs do not occur.

[0009]

【Example】

 Embodiments of the present invention will be described below with reference to the drawings using a coin type lithium battery. Figure 1 shows a schematic diagram of the trimming of the sealing plate by pressing. In the figure, 11 is a cutting die and 12 is a cutting punch. 13 in the figure is the clearance at the time of trimming. In the past, it has been common to machine with a clearance radius of 0.01 mm to 0.02 mm. Therefore, the clearance at the time of trimming was changed stepwise from 0.01 mm to 0.05 mm to form a sealing plate, and the presence or absence of sharp burrs, the rate of galling with the insulating gasket, and the area of the fracture surface were observed at that time. The results are shown in (Table 1). Regarding the material plate thickness, two types of 0.2 mm and 0.3 mm were examined. For the evaluation of the sheared surface and the fractured surface of the cut surface, the dimension in the vertical direction was used as shown in the sectional view of FIG. The assembly with the gasket was performed using our production equipment.

[0010]

[Table 1]

As can be seen from this table, a sealing plate having no folded portion was provided with a uniform fracture surface at its periphery, and a fracture surface having a thickness of 1/5 or more of the sealing plate material plate thickness was provided. By setting the clearance radius to 0.04 mm or 0.05 mm, it is possible to suppress the occurrence of burrs at the open end and prevent galling during assembly with the insulating gasket.

[0012]

[Effect of device]

 As is clear from the above description of the embodiment, the sealing plate trimming portion is provided by providing a uniform fracture surface at the periphery by appropriately setting the clearance during trimming in the sealing plate having no folded portion. It is possible to prevent sharp burrs from occurring, reduce the incidence of defects in the battery manufacturing process, and improve productivity.

[Brief description of drawings]

FIG. 1 is a schematic diagram of trimming of a sealing plate according to an embodiment of the present invention.

FIG. 2 is an enlarged sectional view of a trimming portion of a sealing plate according to an embodiment of the present invention.

FIG. 3 is a half sectional view of a coin-shaped manganese dioxide / lithium battery using a sealing plate having no folded portion.

FIG. 4 is a cross-sectional view of a trimming portion of a conventional sealing plate. (A) A cross-sectional view of a sealing plate having a folded portion at the peripheral edge (b) A cross-sectional view of a sealing plate having no folded portion at the peripheral edge (c) FIG. 4 ( b) Enlarged sectional view of part a

[Explanation of symbols]

 11 Cutting Dies 12 Cutting Punches 13 Trimming Clearance (Radius) 31 Battery Case 32 Positive Electrode Mixture 33 Separator 34 Metal Lithium (Negative Electrode) 35 Insulating Gasket 36 Sealing Plate 41 Folding Portion of Sealing Plate 42 Sharp Barrier Folding Down Trimming part of sealing plate without parts

Claims (2)

[Scope of utility model registration request] 1. A sealed battery comprising a battery case also serving as a positive electrode terminal, a sealing plate also serving as a negative electrode terminal, and a power generating element sealed by an insulating gasket, wherein the sealing plate has no folded portion at its periphery. The sealed battery is characterized in that a uniform fracture surface is provided on the periphery of the opening end. 2. The sealed battery according to claim 1, wherein a fracture surface having a thickness equal to or greater than ⅕ of the material plate thickness used at the periphery of the opening end portion is provided.