JPS6011425B2 - Alkaline battery manufacturing method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing an alkaline battery characterized by applying gold plating to the negative terminal surface of the alkaline battery.

Alkaline batteries have traditionally used zinc as the negative electrode active material.
Alkaline-zinc batteries using metal oxide as the positive electrode active material and caustic alkali as the electrolyte, such as silver oxide batteries, mercury oxide batteries, nickel-zinc batteries, etc. that use monovalent or divalent silver oxide as the positive electrode active material. Due to its voltage stability during discharge and excellent low-temperature characteristics, demand for it as a power source for electronic wristwatches, camera exposure meters, electronic desktop calculators, and various precision measuring instruments has increased significantly in recent years, and various improvements have been made. being done.

However, a problem with this type of battery is that the alkaline electrolyte flows over the surface of the negative electrode. The rate of creeping is further accelerated by the negative electrode potential, especially on the negative terminal surface, so this type of battery requires special treatments on the sealing part, such as intervening adhesives or liquid packing materials. If no intervention is taken, the electrolyte will seep out onto the negative terminal surface several months after manufacture, corroding the terminal surface, and in practical terms, the mirror orientation will deteriorate the electrical contact with the equipment being used. there were.

From these viewpoints, corrosion-resistant metals have been used on the negative terminal surface of batteries, and metals with poor corrosion resistance have been coated with corrosion-resistant metals to prevent these electrical contact failures. For example, titanium, chromium, etc. have high electrical resistance, which increases the internal resistance of the battery itself, that is, the sum of the contact resistance and the resistance of the power generating element itself.
For this reason, there has been an attempt in the past to form a layer of gold with a thickness of 0.05 to 0.5 mm on the negative electrode terminal surface, which has excellent corrosion resistance and low electrical resistance. For this purpose, many methods have been devised to plate only the necessary parts of the negative electrode terminal surface.For example, partial gold plating methods such as the Dallick method and shift method, or the material of the metal container itself, have been devised.
Only the negative terminal part is striped or button plated with gold, or is further crimped with gold foil.
Attempts have been made to form gold only on the exposed part of the negative electrode terminal when punching by press working. However, in partial gold plating, there are many problems such as non-uniformity in the shape of the negative electrode metal container, control of the plating liquid level, cleaning of electrode pins, removal of gold plated products, etc.
Parts supply method It is difficult to control the process, such as the lifespan of felt rolls, etc., and due to these factors, the plating surface may become cloudy or uneven.
Defects peculiar to plating, such as streaks, frequently occurred, and the quality of the plating was extremely low. Further, even when nickel plating, which has a high affinity with gold, was applied before gold plating, the number of walking crabs was only about 30 to 40%, which was not profitable. Furthermore, by providing a gold layer on the material itself and exposing the gold layer only in the necessary parts by press working, the thickness of the gold layer can be reduced by lr.
If the above-described formation is not performed, peeling, scratches, dents, etc. may occur when contacting a press mold or during drawing processing, resulting in an extremely unsightly appearance. Moreover, the yield in this case was only about 40 to 50%, and as a battery parts processing method that relies on economies of scale, it was not an economic problem. The present invention utilizes the electromotive force of the battery itself,
Gold ions in the gold plating solution are electrolytically reduced on the negative electrode surface of the battery to form a thin gold film. Ultrasonic waves, etc. This provides a method for forming a gold layer on the negative electrode terminal surface while applying vibrations.

An embodiment of the present invention will be described in detail below.

In FIG. 1, reference numeral 1 denotes a cylindrical metal case with a bottom, and a positive electrode mixture 2, which is a mixture of a positive electrode active material and a conduction aid such as graphite, is pressure-molded and crimped onto the inner bottom of the case. The metal case 1 is made of an aluminum killed or silicon killed steel substrate plated with nickel, and the positive electrode active material is silver oxide, mercury oxide, manganese dioxide, nickel oxyhydroxide, or the like. Therefore, the metal case 1 also serves as a positive terminal. A separator 3 made of a porous polyethylene film is arranged on the upper surface of the positive electrode mixture 2. 4 is a roughly dish-shaped metal container, the inner surface of which is made of a metal with a hydrogen overvoltage close to that of zinc, which is the anode active material, such as tin, cadmium, copper, etc., and the outer surface made of highly corrosion-resistant stainless steel or It is made of a clad material laminated with titanium alloys placed in different positions, and the inside contains 55% of mercury.
Contains reddened zinc powder 5 to which ~1% by weight has been added,
Also serves as the negative terminal.

6 is an insulator attached to the periphery of the metal container 4 by iron bonding or integral molding, and is made of synthetic rubber, synthetic resin, etc.
This is to insulate the negative electrode and the positive electrode and prevent leakage of electrolyte to the outside.

The battery is sealed by bending the green part la of the metal case 1 inward and pressing the insulator 6 against the edge of the metal container 4. The negative terminal surface of the silver oxide battery thus obtained was plated with gold using an ultrasonic vibrator as shown in FIG. In the figure, 7 is a cleaning tank that stores electrical and chemical gold plating solution 8. 9 is an ultrasonic oscillator that oscillates at an ultrasonic frequency range by supplying power from an external power source; 10
1 is a converter that converts the electrical ultrasonic energy from the oscillator 9 into mechanical vibration energy, and 1 1 is a diaphragm 12 and a plating solution that are vibrated by the power from the vibration changer 10 and placed in the cleaning tank 7. This is a vibrator that applies ultrasonic vibration to 8.

Then, the battery 13 is placed in the cleaning tank 7, and ultrasonic vibration is applied by the diaphragm 12. The frequency of the vibration applied is 3 plates Xz
, the time is 3 seconds.

This vibration activates the surface to be plated, removing oil and
Dust, electrolyte, etc. are removed, so-called cleaning is performed, the battery surface temperature rises, and the battery electromotive force extracted into the plating solution is maximized, instantaneously, and efficiently. Electrolytic reduction deposition is performed efficiently. The frequency and time of vibration applied to the battery are
From the results of experiments under various conditions, it was found that a frequency of 30 to 90 KHz and a time of 1 to 1 light are preferable, regardless of the liquid I property of the plating solution. In the case of a frequency of 90K ratio, if vibration is applied for more than 2 seconds, a minute gap may be created between the contact surface between the metal container 4 and the insulator 6, the plating on the bending area 1a of the metal case 1 may peel off, or extreme damage may occur. Occasionally, cracks occur in this area, which is not desirable.
Further, when the frequency is about 20 KHz or less, unless vibration is applied for about 1 minute or more, the thickness of the gold plating layer 4a becomes thin or the thickness distribution becomes sparse, which makes the appearance unsightly and reduces the commercial value. In addition, since the electromotive force of the battery itself is used, if it is left in the plating solution for a long time, the actual capacity of the battery will decrease due to self-discharge, and in extreme cases, the battery capacity will be halved, making it useless. There are also major difficulties in mass production.
Also, the structure shown in Figure 1 has a height of 5.4 ribs and a diameter of 11.6 mm.
On the other hand, in a silver oxide-zinc alkaline battery with a capacity of 180 hAh, the product of the present invention (■) was subjected to ultrasonic vibration at a ratio of 30K for 2 seconds, and the product (B) was applied with ultrasonic vibration at 10KHz for 9 seconds.
Continuous discharge characteristics were compared between battery 1 and battery 2 using a negative electrode metal container obtained by the selective gold plating method at a constant resistance of UtaQ. The results are shown in the table below. The number of samples to be tested was 20 for each, and the average utilization rate was calculated as the average actual capacity ÷ 18 hours.
It is expressed as Ah (theoretical capacity) x 100 [%]. The composition of the gold plating solution used in this experiment is as follows.

o Cyanide Kinrikirium...8 evening/evening.

Cyanidation power rewam...30 evening/so Potassium carbonate...15 evening/so potassium diphosphate...25 evening/so liquid temperature
・・・・5zu○ soil 2℃℃ liquid
...PHIO~11 The above plating solution 1
The diameter of the negative terminal surface is 9 ribs, and the thickness of the gold plating is 0.
If plating is performed as 2r, it is possible to plate about 3 sides as a battery. As described above, according to the method of the present invention, it is possible to perform gold plating without wasting expensive gold and minimizing capacity loss of the battery, and the type of plating solution can be changed, that is, electrolytic gold plating grade, electroless scale gold plating grade. Uniform plating is achieved by applying vibration, uniformly activating the plated surface, and the synergistic effect of the stable discharge level unique to alkaline-zinc batteries makes it extremely ideal. This makes it possible to establish conditions for gold plating.

Regarding the temperature of the plating solution, it should be set at a temperature that does not have a negative effect on the battery, that is, below 7 qo, preferably below 60 qo. Temperatures below this have little effect on the finish and strength of the plated surface. Rather, the optical selection differs slightly depending on the temperature range, and the initial goal can be achieved without causing any practical problems. As described above, the manufacturing method of the present invention is extremely suitable for mass production and is particularly economical.

[Brief explanation of drawings]

Figure 1 shows a manufacturing method according to an embodiment of the present invention, and is a sectional view of the main parts of a silver oxide battery with gold plating on the negative terminal surface, and Figure 2 shows a plated silver oxide battery equipped with an ultrasonic vibration device according to the present invention. It is a schematic diagram of the configuration of the device. 1...Battery container that also serves as a positive terminal, 4...
...Battery container that also serves as a negative electrode terminal, 4a...Gold plating layer, 8...Gold plating solution, 12...Vibration plate, 13...
…·battery. Figure 1 Figure 2

Claims (1)

[Scope of Claims] 1. An alkaline battery with a power generating element sealed by a metal container serving as a positive terminal, a metal serving as a negative terminal, and an insulator that insulates both the containers is immersed in a gold plating solution. Ultrasonic vibrations with a frequency of 30 to 90 KHz are applied to the plating liquid for 1 to 30 minutes.
A method for producing an alkaline battery, characterized in that gold plating is applied on the negative electrode terminal surface by electrolytic reduction using the electromotive force of the battery itself while applying the voltage for 10 seconds. 2. The method for producing an alkaline battery according to claim 1, wherein the gold plating solution has a temperature of 70° C. or lower.