JPS5814461A - Battery - Google Patents

Abstract

PURPOSE:To decrease surface energy of the surface of a battery container comprising a battery case and a sealing plate to make difficult to get wet with an electrolyte and suppress electrolyte creepage and increase electrolyte leakage resistance by forming a plated layer obtained by codeposing solid fluorinated graphite in the part connecting with a gasket. CONSTITUTION:In a cross section figure of a button type silver oxide battery, 1 shows a stainless steel sealing plate which has nickel plated layer 1' obtained by codepositing fluorinated graphite on its outer surface and tin plated layer 1' on its inner surface. 8 shows a battery case having nickel plated layer 8' obtained by codepositing fluorinated graphite in both surfaces of stainless steel. The nickel plated layer obtained by codepositing fluorinated graphite has electric conductivity, small surface resistance, water repellent property of fluorinated graphite, and property difficult to get wet with an electrolyte compared with the surface of usual nickel plated layer. In the case of electrolyte leakage from the sealing part, codeposited plating applied in at least one part of the outer surface of the battery container is more effective to prevent extending of wetting by electrolyte creepage.

Description

DETAILED DESCRIPTION OF THE INVENTION The object of the present invention is to improve the leakage resistance of a battery.

Generally speaking, the so-called crimp method is used as a battery sealing method, in which the battery case and sealing plate are joined through a gasket tracker. Among these, the shape and dimensions of the gasket tracker and various other parts, materials, sealing conditions, sealant selection, etc. Various methods have been studied to achieve more reliable sealing. On the other hand, recently there has been a particularly strong demand for batteries with excellent leakage resistance and storage stability that can withstand long-term use, including electronic watches and calculators. Further efforts are needed to improve the long-term reliability of liquids.

In particular, silver oxide batteries and mercury batteries that use alkaline electrolytes such as potassium hydroxide and sodium hydroxide.

In alkaline manganese batteries, the leakage of the electrolyte onto the metal surface of the battery container, the so-called creep phenomenon, is significant, so there is a limit to leakage resistance with mere mechanical sealing technology.

In addition, this electrolyte creep phenomenon is largely controlled by the potential applied to the battery container. In the case of alkaline electrolytes, the negative electrode side, which has a zinc potential, creeps up significantly, and the negative electrode side tends to leak. At present, there is still no definitive solution to these problems.

The present invention reduces the surface energy of the surface of a battery container consisting of a battery case and a sealing plate to make it difficult to wet with electrolyte,
This provides a means for suppressing the creep phenomenon and improving leakage resistance.

In order to solve the above problem, the present invention is characterized in that a plating layer in which solid fluorinated graphite is eutectoid is provided on at least a portion of the battery container that is connected to the gasket.

Solid fluorinated graphite is used as a positive electrode active material in non-aqueous electrolyte batteries, and because it has extremely low surface energy, it is also used as a water repellent, and because it is thermally and chemically stable and has good lubricity. It is also used as a lubricant. In the present invention, solid fluorinated graphite is chemically stable to acids, alkalis, organic solvents, etc., does not decompose even at high temperatures of 40°C to 600'C, and has low surface energy and is difficult to wet with electrolyte. We focused on the fact that we have discovered a method of eutectoiding fluorinated graphite onto the plating layer, as described below, and applied the plating layer to the surface of the battery container that requires prevention of creep of the electrolyte. It is applied to a battery by forming it in part or in whole as a means for preventing liquid leakage in a battery.

As a method for eutectoiding fluorinated graphite onto the nickel plating layer, electroplating is performed by suspending or dispersing the fluorinated graphite completely or dispersing it in a normal nickel-watt bath and stirring it. Add a cationic surfactant to give

The base material to be plated is iron, which is commonly used for battery containers.

In the case of stainless steel, a plating layer with good adhesion can be obtained. In this case, for example, at a current density of 2 to 8 human skin, plating n is 3 to 3 with the addition of fluorinated graphite of about 49/1 or more.
Graphite fluoride is eutectoid on the nickel plating layer at a weight ratio of 6. When the amount of fluorinated graphite in the plating solution is less than 4 f/1, the fluorinated graphite in the plating layer is less than 3%.

After plating, the plating layer containing graphite fluoride can be simply washed and dried with water to remove foreign matter, but in particular, in order to more completely remove the surfactant remaining on the surface,
If necessary, methods such as ultrasonic cleaning with warm water or a solvent may be used in combination. The nickel plating layer with fluorinated graphite eutectoid has the electrical conductivity inherent to nickel, has a surface resistance that is almost as low as nickel, and also has the water repellency of fluorinated graphite, making it superior to ordinary nickel. Compared to the surface of the nickel plating layer, it is significantly wetter with the electrolyte.
＜It has the characteristic of being ugly.

Next, the present invention will be explained by examples.

The figure is a cross-sectional view of a button-shaped silver oxide battery to which the present invention is applied. In the figure, 1 is made of stainless steel with a nickel plating layer 1' coated with graphite fluoride eutectoid on the outer surface and a tin plating layer 1' on the inner surface. 2 is a negative electrode made of frozen zinc powder, 3 is a liquid retaining material made of cotton fiber, 4 is a separator made of polypropylene foam sheet, and 6 is a positive electrode made of ferrous oxide powder that is pressure-molded. , 6 is a positive electrode ring made of stainless steel, 7 is a nylon gasket, and 8 is a battery case in which a graphite fluoride nickel plating layer 8' is provided on both sides of the stainless steel.

The nickel plating layers 1' and 8' were plated on a plate-like original plate and then processed into a sealing plate 1 or a battery case 8, and the plating bath was nickel sulfate 280 f/(
1, chive chloride 45 f/l boric acid 4 ot/1
ni(C6F17SO2)fH(02H5)2R)"?-
Add 100'M of a cationic surfactant with the structure of
Furthermore, the weight ratio of fluorographite in the plating layer was 4.

The electrolyte injected into the battery is a nearly saturated solution of zinc oxide in so% potassium hydroxide, and is mainly impregnated into the liquid retaining material 3 and the negative electrode 2, with some free liquid remaining in the battery. ing.

In order to experimentally confirm the effects of the battery of the present invention, (IL) As a conventional example, each nickel plating layer in the figure was formed to a thickness of 10 μm in a normal Watt bath at a current density of 5 persimmons. (b) As the first example of the product of the present invention, the plating layer as shown in the figure is provided9.(C) As the second example of the product of the present invention, the nickel plating of the sealing plate is The same eutectoid plating as shown in the figure is used, and the battery case has the same normal nickel plating as the conventional example on both sides, and the diameter is 11.6.
I made a prototype battery with a configuration of 6.4B in height. Furthermore (IL
), (b), and (0) were all under the same conditions except for differences in the shape of the parts used, the sealing conditions, and the plating layer.

Each battery was left at 46℃ and relative humidity of 96℃ for 100 days.
When we observed the leakage situation, we obtained the results shown in the table below.

As can be seen from this table, in all the products of the present invention, there was no leakage from the battery container to which the negative electrode potential was applied, that is, from the sealing plate side.

This proves the effect of the extremely small creep phenomenon of the electrolytic solution on the surface of the eutectoid plating layer, and shows a remarkable difference from the conventional example. Further, although the battery case side is relatively difficult to leak even in the conventional example, in the case of the present invention, leakage is completely prevented due to the effect τ' of the eutectoid plating layer on the battery case surface.

As described above, the leakage-proof effect of the present invention is tremendous, but there are various embodiments, and in addition to the above-mentioned examples, after the parts are processed, eutectoid plating may be applied only to the sealing parts that require eutectoid plating. In the case of battery cases, eutectoid plating only on the inner surface is also effective.In short, it is sufficient to plate at least the surface of the battery container that is connected to the gasket at the sealing part. In addition, in the event of leakage from the sealing part, eutectoid plating should be applied to at least a portion of the outer surface of the battery container to prevent the electrolyte from creeping onto the surface of the container and spreading wetting force. The more you apply it, the more effective it will be.

In addition, in the previous example, eutectoid plating of graphite fluoride was explained, but in addition to nickel, there are also cases where battery containers are plated with copper, tin, or other alloys. There is copper or tin plating on the inner surface of the sealing plate, and copper plating on the outer surface of the battery container. In these cases, the same effect can be obtained by forming a eutectoid plating layer of graphite fluoride according to Akira Honjo's idea.As a typical example of the treatment method for these platings, a complete plating of graphite fluoride eutectoid copper plating is used. In this case, as in the case of nickel, a cationic surfactant can be added to a normal copper sulfate plating bath, and electrodeposition can be carried out in a plating bath in which graphite fluoride is dispersed. The amount of graphite fluoride in this plating layer is 3 to 3, as in the case of nickel plating.
Eutectoid nickel plating is possible, and the surface wetting resistance is not much different from that of eutectoid nickel plating.

Furthermore, although the previous example has been explained using alkaline electrolyte-based batteries, the present invention can be applied to nickel-cadmium batteries, non-aqueous electrolyte-based batteries with lithium as the negative electrode, and even lead-acid batteries that use acidic electrolytes. is also effective.

[Brief explanation of the drawing]

The figure is a sectional view of a battery in an embodiment of the present invention. 1... Sealing plate, 1'... Nickel plating layer eutectoided with graphite fluoride, 1'... Tin plating layer, 2... Negative electrode , 4...Separator, 6...Positive electrode, 8...Battery case,
8'...Nickel plating layer with fluorinated graphite eutectoid.

Claims (1)

[Claims] A battery characterized in that a plating layer in which fluorinated graphite is eutectoid is provided on at least a surface of the battery container that is bonded to a gasket.