JPH056303B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Application Field] The present invention relates to an improvement in a button-type alkaline battery having a gold layer on the negative electrode lead surface. [Prior Art] Conventionally, as shown in Fig. 2, it has been known that a button-type alkaline battery is provided with a gold layer 1a on the negative electrode lead 1 as a requirement for electronic equipment using the battery. Ta. Furthermore, many of the batteries used in these applications are required to be extremely thin. The thinner the battery, the smaller the sealing area, and the lower the leakage resistance. As a countermeasure, it is known that providing a gold layer on the part sealed through the gasket improves leakage resistance, and it has been used in batteries that have been on the market for a long time, such as UCC's No. 392. ing. [Problems to be Solved by the Invention] It is desirable that the gold layer be present on the entire surface of the sealed portion 1l in order to improve leakage resistance. However, on the other hand, mercury, which is added to prevent corrosion of the negative electrode active material of button-type alkaline batteries, causes the gold layer to amalgamate and come out on the outside of the can. Leakage of mercury outside the battery is an unacceptable problem, as is leakage of electrolyte.
In order to provide a button-type alkaline battery that has good leakage resistance and has a gold layer on the negative electrode lead surface, it is necessary to solve the above-mentioned mercury leakage problem. Furthermore, if the battery thickness becomes extremely thin, the folded structure of the negative electrode can used in ordinary button-type alkaline batteries cannot be adopted. This folded structure improves the strength of the negative electrode can in the direction perpendicular to its axis, lengthens the leakage path, and increases the time it takes for the leakage to proceed, thereby increasing the usable period in practical use. There is. An alternative method is needed for ultra-thin button-type alkaline batteries. [Method for solving the problem] A battery is constituted by a positive electrode can 3, a positive electrode active material 4, a negative electrode can 1, a negative electrode active material 2 whose main ingredient is zinc oxide, separators 5 and 5a, a gasket 6, and an alkaline electrolyte, A gold layer 1a is provided on the surface of the sealing part 1l of the negative electrode can 1, and a part of the gold layer sealed by the gasket is removed in a ring shape as shown in 1b to prevent liquid leakage and mercury from flowing outside. Prevented leakage. Moreover, the shape of the negative electrode can 1 is parallel to the plane 1d perpendicular to the central axis 1c of the can, or
Problems with the can strength and the length of the leakage path were solved by providing a so-called hat-shaped shape with 1 m of flanges intersecting at an angle 1f of 40° or less. If the angle of the brim portion 1m is perpendicular to the central axis 1c of the can, the shape of the negative electrode can 1 is strong against the compressive force in the direction perpendicular to the axis that occurs when the positive electrode can is caulked and sealed. The 1m brim is the central axis of the can.
As it deviates from the direction perpendicular to c, it becomes weaker against the compressive force. Therefore, it is desirable that the angle 1f of the brim is within 40° with respect to the direction 1d perpendicular to the central axis 1c of the can. As a method for forming the gold layer 1a on the negative electrode can 1, plating can be used. or,
A ring-shaped groove 1g is formed in the flange 1m of the negative electrode can 1 in advance, a coating is applied to this groove, the coating is plated, and a cut is made in the plating layer of the sealing part by a so-called mask plating method in which the coating is removed after plating is completed. 1b and groove 1g.
It is also possible to remove the gold layer after plating, in which case the easiest method is to groove the can. In order not to remove too much gold coating and to minimize the effect on the strength of the can, the width 1i of the groove is less than half of the width 1h of the brim, and the depth 1k is the same as the thickness 1j of the brim. 1/2
Must be less than or equal to [Function] Ring-shaped Fe,
The leakage of mercury to the outside can be prevented without impairing the leakage resistance by providing the band-shaped portion 1b of a metal that does not easily become aqueous, such as Ni or stainless steel. Since this has only occurred in certain batteries, it is clear that this is possible by making the gold layer in the mercury leak path discontinuous. The cut 1b in the gold layer is useless inside the battery where the negative electrode active material 2 is present. Also, on the outside 1o of the can, the mercury reaches one end of the cut in the gold layer, which is also useless. Therefore, it is necessary that the cut 1b in the gold layer exists in the portion 1l that is sealed with a gasket or a sealant. In manufacturing ultra-thin batteries, it is clear that it is advantageous for the outer periphery of the negative electrode can to have a flange 1m rather than a folded structure 1n, as it can reduce the required thickness of the sealing part. It is. The shape of this negative electrode can with a 1 m brim is as follows:
It has the advantage of being easy to process for both mask plating and groove processing. The gold layer may be formed by using a clad plate as a material or by vapor deposition, but plating is the cheapest and easiest method. It is obvious that mask plating and groove machining are effective means for providing the cuts 1b in the gold layer 1a of the negative electrode can 1. [Example] Using the present invention, a button-type alkaline battery having an outer diameter of 5.8 mm and a thickness of 1.2 mm was manufactured. The negative electrode can 1 has a stainless steel and copper clad plate as a base material, a gold layer is provided by gold plating, and a groove is cut in a part of the positive electrode facing surface of the 1 m brim part, and the gold layer and negative electrode are formed in a ring shape. A portion of the can base material was removed. Additionally, a commonly used asphalt pitch sealant was applied between the gasket and the negative electrode can. Below, we will show comparison data between a product using a negative electrode can without gold plating and a conventional product with gold plating applied to the entire negative electrode can. The method was to check for leakage after storage for 2000 hours at 40°C and 90% relative humidity.

〔Effect of the invention〕

In the present invention, the brim of the negative electrode can has a groove and a portion without a gold layer, and is filled with a sealant, so that it has the following effects. Leakage of mercury can be prevented in areas where there is no gold layer. Since the groove is filled with a sealant, it is possible to prevent mercury from being transported using gold chips from the groove cutting process as a medium. Since the groove is filled with a sealant, it is possible to prevent mercury ions from flowing out due to bridging of leaking electrolyte from inside the battery.

[Brief explanation of the drawing]

FIG. 1 is a half-sectional view showing an embodiment of the present invention, FIG. 2 is a half-sectional view of a battery using a conventional negative electrode can with folded parts, and FIG. FIG. 4 is a half-sectional view showing the usable range when the brim portion of the negative electrode can of the present invention is bent in the opposite direction to that shown in FIG. FIG. 5 is a half sectional view showing an embodiment of a negative electrode can in which a groove is provided in a part of the part sealed with the gasket of the present invention. 1... Negative electrode can, 1a... Gold layer formed on the surface of the negative electrode can, 1b... Ring-shaped base material exposed portion on the surface of the negative electrode can where no gold layer is present, 1c... Central axis of the negative electrode can, 1d ...plane perpendicular to the center axis of the negative electrode can, 1
e...Direction of the brim of the negative electrode can, 1f...1d and 1
Angle where e intersects, 1g...Groove provided in the brim of the negative electrode can, 1h...Brim width of the negative electrode can, 1i...1g
width, 1j...thickness of the brim, 1k...depth of 1g, 1l...portion sealed by the gasket of the negative electrode can, 1m...brim part of the negative electrode can, 1n...
Folded portion of the outer periphery of the negative electrode can, 1o...outside portion of the negative electrode can, 2... negative electrode active material, 3... positive electrode can, 4...
Positive electrode active material, 5... separator, 5a... electrolyte impregnated material, 6... gasket.

Claims (1)

[Scope of Claims] 1. A positive electrode can that also serves as a positive electrode lead, a positive electrode active material, a negative electrode can that also serves as a negative electrode lead, a negative electrode active material containing zinc chloride as a main ingredient, a separator, a gasket, and an electrolyte. A button-type alkaline battery having a button-type alkaline battery, wherein a flange is formed on the outer periphery, and a thin gold film is formed on almost the entire surface of the battery, except for one or more ring-shaped areas where there is no thin gold film where the flange and the gasket contact each other. and a negative electrode can made of a metal that is difficult to form into a metal, having a groove at a position corresponding to the part without the thin film, and a sealing agent filled in the part without the thin film and the groove. A button-type alkaline battery characterized by: 2 The flange of the negative electrode can is opened at a 40 degree angle in a direction in which the tip of the flange moves away from the bottom surface of the positive electrode can with respect to a plane perpendicular to the central axis of the negative electrode can, and in a direction that approaches the positive electrode can. Claim 1, which has a tapered shape of 40 degrees.
Button-type alkaline batteries as described in section. 3. The button-type battery according to claim 1, comprising a negative electrode can in which the width of the groove is about 1/2 or less of the width of the flange. 4 The depth of the groove is approximately 1/2 of the depth of the collar.
The button-type alkaline battery according to claim 1, having a negative electrode can having a depth of: