JPS6037653A - Manufacture of alkaline battery - Google Patents

Abstract

PURPOSE:To manufacture a negative electrode which can be used for assembling a thin high-capacity alkaline battery by punching an expanded or punched zinc metal into a given size and amalgamating the thus obtained body with an aqueous solution of a mercury compound. CONSTITUTION:An expanded pure zinc plate is punched into a disk-like form, and this is immersed in an aquious HgCl2 solution. The time of the immersion is adjusted so that the disk plate is amalgamated in a given degree while performing stirring. The thus obtained amalgamated disk plate, after being taken out of the solution, is washed with water and dried before being packed in a negative case 6. Next, a liquid-holding member 4 is placed on the zinc 5, and electrolyte consisting of an aqueous caustic potash solution saturated with HgO is pured over the member 4. Then after amalgamation is completed, the negative part is combined with a positive part 2 on which a separator 3 is placed to seal the battery.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an alkaline battery, and in particular to a method for manufacturing its negative electrode.

Conventional configurations and their problems With the development of electronics, the operation of watches has become mainstream using multiple circuits, and the accuracy of watches has improved significantly. In addition to this, today's watches are required to be small and thin with fashion in mind. Accordingly, the alkaline batteries used as the power source are also required to be small and thin.

Conventionally, powdered zinc hydrate has been used as the negative electrode active material of alkaline batteries. When mass-producing batteries, powdered zinc hydrate was weighed in a container with a certain volume, so-called folding, and filled into a negative electrode container. in this way,
The weighing variation is about L:2m2, and the capacity variation due to this error is about smAh. Currently, the power consumption of a single-function watch with only a one-minute hand using C2MOS LSI is approximately 5 mAh or less per year, and the power supply is required to operate for approximately 2 years. ,
From Ah, due to powdered zinc hydrate. pli,i;
Variation in j results in a 30% capacity error.

As a result, the battery capacity design also takes into account variations, resulting in a 30% lower capacity than the ideal state.

In the case of flat batteries, there is still a process in which the mountain-shaped powdered zinc hydrate that is weighed and placed in the negative electrode container is leveled uniformly in the thin container, but this is not possible during the mass production process. This is quite a difficult task. If a thin zinc plate is punched out into a circular shape and this is used as the active material, the weighing variation will be ±0.2
It will be about mg.

Therefore, there is almost no need to consider variations in battery capacity setting 1, and a substantial capacity amplifier is possible. However, the surface area is less than 1/10 of that of powder, which causes the disadvantage that battery performance, especially pulse discharge characteristics, deteriorates.

It has been said for some time that using a thin zinc plate in the form of an expanded band with a wider surface area and punching it out can substantially increase capacity by improving weighing accuracy without degrading battery performance, but this is not practical. There were many points.

That is, in an alkaline battery using zinc, self-discharge is promoted due to the generation of hydrogen gas due to the corrosion and dissolution of zinc by the electrolyte.

As a countermeasure to prevent this, a certain amount of hydration with mercury is necessary to maintain a high hydrogen overcharge, but zinc that has been hydrated in advance is extremely brittle, and zinc that is in the form of an expanded band is difficult to maintain due to its shape. It is impossible to maintain this during the mass production process, and even more so, it will break into pieces during punching.

There is also a method of punching expanded banded zinc, adding powder of a mercury compound such as HqO, and hydrating it in a negative electrode container. However, this method was impractical because it produced a large amount of products such as the following, impairing the performance and reliability of the battery.

OBJECTS OF THE INVENTION It is an object of the present invention to provide a method for producing a negative electrode that eliminates the drawbacks of the above-mentioned conventional examples and provides a thin alkaline battery with high capacity.

Structure of the Invention The present invention involves punching a punched metal of zinc into a predetermined size, and then punching the punched metal into a predetermined size.
For example, it is immersed in an aqueous solution of HqC12, hydrated to a predetermined amount, washed with water, dried, then filled into a negative electrode container, filled with electrolyte, and combined with a positive electrode to form a battery.

Here, in order to suppress the generation of hydrogen gas from the inner surface of the negative electrode until immediately before sealing, it is preferable to use an electrolytic solution in which HqO is dissolved to a saturation degree.

Description of Example A pure zinc plate with a diameter of 6.3 mm and an aperture ratio of 90% and a weight per unit area of 43.11 ng/crl was
Punch out a disk shape of m1l+ and add 10% by weight of H.
It is immersed in a qC12 aqueous solution, and the immersion time is adjusted while stirring so that it is frozen to 10% by weight. After taking it out, washing it with water, and drying it, it was filled into a negative electrode container. Then, a liquid-containing plate was placed on the zinc, and a 40% by weight aqueous solution of caustic potash was added with HqO.
9 μl of an electrolytic solution saturated with was injected, and after waiting for hydration for 30 seconds, it was combined with a positive electrode portion on which a separator was placed and sealed.

Figure 1 shows 5R910 (diameter 9
．． A button-shaped alkaline battery with a total height of 2 mm and a total height of 1 mm is shown.

In the figure, 1 is a positive electrode case made of nickel-plated iron, 2 is a positive electrode pen made of 97% by weight of silver oxide and 3% by weight of silver powder, 3 is a separator, 4 is a liquid-containing material, and 5 is a zinc hydrate negative electrode. . 6 is a sealing plate having a copper layer on the inner surface and serving as a negative electrode container;
7 is a gasket made of nylon.

FIG. 2 shows a battery A according to the invention shown in the above embodiment,
For battery B using zinc hydrate powder as the negative electrode, 30 K
, shows a discharge curve when discharging with a load of G'. The shaded area indicates variations in the characteristics of the 10 batteries. It can be seen that battery A has a higher capacity and less variation than battery B.

In the above example, an electrolytic solution in which mercury oxide was dissolved was injected into the negative electrode side. This is to prevent gas generation by hydrating the inner surface of the negative electrode container and helping to hydrate the parts of the expanded zinc negative electrode that are not sufficiently hydrated. When assembling a battery by chemical treatment, it is not necessary to add mercury oxide to the electrolyte.

Further, although expanded band processed negative electrode zinc was used, the same effect in terms of weighing accuracy and surface area can be obtained even if a large number of fine holes are punched out.

In addition, although the example shows a punched product of extracted band zinc that has been hydrated with a HqCIJ2 aqueous solution, HqC7
The same effect can be obtained with 1 or HqCN.

Effects of the Invention As described above, the present invention uses punched metal or expanded metal of zinc and performs hydration treatment with an aqueous solution of a mercury compound, so that a large amount of ice can be treated at one time and hydrated uniformly. Ru. Therefore, in battery design, consideration of measurement variations can be minimized, and the capacity can be substantially increased, which is particularly effective in ultra-small and thin batteries.

[Brief explanation of drawings]

FIG. 1 is a partially sectional side view of an alkaline battery according to an embodiment of the present invention, and FIG. 2 is a comparison diagram of battery characteristics.

Claims (2)

[Claims] (1) A method for producing an alkaline battery, which includes the step of cutting expanded metal or punched metal of zinc into a predetermined size, and then hydrating it with an aqueous solution of a mercury compound. (2) The method for producing an alkaline battery according to claim 1, wherein the mercury compound is mercury chloride or mercury cyanide.