JPH0155544B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing a battery case for use in button-type or thin batteries such as silver oxide batteries, mercury oxide batteries, or alkaline manganese batteries, and improves the battery case to achieve stable discharge performance and excellent performance. The purpose of this invention is to provide a battery that is resistant to leakage.

A small button battery is typically constructed as shown in FIG. In the figure, 1 is a cup-shaped metal battery case, which is made of stainless steel, titanium alloy, or iron with corrosion-resistant nickel plating. Reference numeral 2 denotes an anode mixture disposed at the inner bottom of the battery case 1, which is formed by pressure molding a mixture of silver oxide or manganese dioxide and a conductive material such as graphite. 3 is a separator, which is made of a synthetic resin film made porous by irradiation with electron beams, laser beams, microwaves, etc., such as polyethylene,
Made of polypropylene, polytetrafluoride polystyrene, etc. 4 is an electrolyte-impregnated material made of non-woven fabric or woven fabric such as nylon, polypropylene, cotton, viscose rayon, etc. 5 is a cathode made of zinc hydride powder, and 6 is a metal sealing plate that closes the opening of the case 1 and also serves as a cathode terminal. A sealing packing 7 is interposed between the open end of the case 1 and the metal sealing plate 6, and prevents leakage of the electrolyte to the outside.
This prevents electrical short circuits between the anode and cathode.

Next, a method for manufacturing a cup-shaped battery case, which is a feature of the present invention, will be explained together with a conventional example.

The metal battery case 1 conventionally used for this type of battery is gradually drawn into a cup shape in multiple steps using typical press working methods such as the progressive method and the transfer method. As shown in the figure, a flange portion 10 of a case 1 was cut using a punch 8 and a die 9. For this reason, cut marks such as those shown in 11 remain on the flange part 10 of battery cases, especially small button-type battery cases, and depending on the equipment used when using the battery, burrs from the cut marks may cause damage to the battery. A short circuit could occur.

Unlike the multi-step deep drawing method described above, this invention enables a battery case to be obtained through a series of punching and drawing processes, and also aims to improve the accuracy of the total height, outer diameter, and inner diameter. This is what I did.

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 2 shows a mold structure for obtaining a battery case according to an embodiment of the present invention, and FIG. 3 shows a cross-sectional view of the cup-shaped battery case that has been punched and drawn.

The specific configuration of the mold structure shown in FIG. 2 will be described below.

The punching die 9 is fixed to the punching machine body,
A thin metal plate 1a made of a stainless steel plate, a nickel plate, a nickel-plated steel plate, etc. placed on a punching die is punched into a disk shape using a punch 13 that slides up and down at corresponding positions.
At this time, in order to prevent the thin metal plate 1a from shifting, a presser plate 12 is placed around the periphery of the punch 13 and moves up and down.
The thin metal plate 1a is pressed and fixed onto the punching die 9. The punched disc-shaped piece is pushed into the punching die 9 by the punch 13, and at this time, the cut surface of the disc-shaped punched piece is pushed into the punching die 9.
The burrs, etc. associated with punching are removed by scraping on the sides.

Further, the punch 13 enters the punching die 9 while pushing the disc-shaped punched piece, and the punch 13 moves the disc-shaped punched piece into the punch 13 by lifting the drawing punch 15 that slides up and down inside the punching die 9. It is pushed into the drawing recess 14 in the center, and the inner surface of the disc-shaped punched piece is drawn into an inverted cup shape so that it follows the shape of the tip of the drawing punch 15, resulting in a small button shape as shown in Fig. 3. A battery case 1 is formed.

The opening edge 16 of the battery case 1, which has been drawn into a cup shape in this way, is formed into a straight cut without any burrs, as shown in Fig. 3, and has improved precision for use in small button batteries. Become something.

As described above, according to the manufacturing method of the present invention, by a continuous series of punching and drawing processes, that is, with the metal sheet pressed against the punching die with the presser plate,
Punch it out into a disc shape with a punch and leave it as is.
In order to insert the disc-shaped punched piece into the punching die, the cut surface of the disc-shaped punched piece is scraped with the side surface of the punching die to remove burrs and the like caused by punching, and then the battery case is obtained by the drawing process of the present invention described above. , a battery with stable discharge performance that does not produce minute protrusions such as burrs on the opening edge of the case, and does not cause short-circuit phenomena caused by minute protrusions such as burrs during the battery assembly process or during battery use. can be provided.

[Brief explanation of drawings]

FIG. 1 is a half-cut side view showing a typical structure of a small button battery; FIG. 2 is a schematic cross-sectional view showing a mold structure for obtaining a battery case in an embodiment of the present invention;
FIG. 3 is a sectional view of a cup-shaped battery case punched and drawn using the mold shown in FIG. 2, and FIG. 4 is a diagram showing a cut of the flange portion of a conventional cup-shaped battery case. DESCRIPTION OF SYMBOLS 1...Cup-shaped battery case, 1a...Thin metal plate, 9...Punching die, 12...Press plate, 13
...Bunching punch, 14...Drawing recess, 15...
...A squeeze punch.

Claims (1)

[Claims] 1 A punching die 9 which is fixed to the punching machine main body and has a drawing punch 15 that slides up and down in the center of the inside, and a drawing recess 14 in the center of the inside, and is provided at a position corresponding to the punching die 9. A method of manufacturing a battery case by punching a thin metal plate 1a using a mold consisting of a punch 13 that slides up and down, and a presser plate 12 that is located at the periphery of the punch 13 and moves up and down. After pressing and fixing the metal thin plate 1a to the punching die surface, the punch 13 is slid to punch out the metal thin plate 1a into a circular shape, and the sheet is pushed into the punching die 9 as it is, and the cut surface of the disc-shaped punched piece is cut into the punching die 9. After that, the disc-shaped punched piece is inserted into the drawing recess 14 in the punch 13 using the punching die 9.
This method for producing a battery case is characterized in that the battery case is pressed in with a drawing punch 15 that slides up and down inside, and is drawn into a cup shape so that the inner surface of the disc-shaped punched piece follows the shape of the tip of the drawing punch 15.