JPS60221957A - Alkaline battery with no added mercury - Google Patents

Abstract

PURPOSE:To improve battery performance by using a negative pole collector given chemical grinding treatment while preventing environmental pollution by using a zinc negative pole with perfectly no added mercury. CONSTITUTION:Oxide and soil are removed from the surface of a collector 5 for smoothing the surface by giving in advance chemical grinding treatment to the negative pole collector 5. Thereby, a uniform zinc-plated layer is formed on the surface where the collector 5 contacts with the gelatinized zinc 4 thus to obtain an alkaline battery with no added mercury with no deterioration in the heavy load performance and little generation of hydrogen gas during the storage or at the end of discharge.

Description

[Detailed description of the invention] The present invention relates to improvements in alkaline batteries.

By using a negative electrode current collector that has been chemically polished, the aim is to prevent pollution and improve battery performance by using a zinc negative electrode that does not contain any mercury.

Conventionally, general alkaline manganese dry batteries have used manganese dioxide as the positive electrode mixture and bag-formed curved lead powder dispersed in a gel-like alkaline electrolyte in which oxidized Tonensen has been dissolved as the negative electrode. This gel-like curved lead negative electrode current collector is as described in JP-A No. 50-2134,
A material such as copper or a copper alloy is generally used, and the surface of the current collector is amalgamated by contacting it with a gelled curved lead negative electrode. For this reason, some surface oxides and dirt are separated,
The curved lead was completely plated, allowing it to function as a current collector. However, there was the possibility of causing mercury pollution problems. To prevent this, mercury-free zinc has come to be used. When mercury-free zinc was used, the surface of the current collector was not amalgamated because mercury was not present in the gelled curved lead negative electrode, and oxides and dirt on the surface could not be separated. As a result, the bent lead plating becomes incomplete, resulting in deterioration of discharge performance, especially heavy load performance, and
In storage.

There was a drawback that hydrogen gas was generated inside the battery at the end of discharge, causing the battery to leak, explode, etc.

The present invention has been made to eliminate the above-mentioned drawbacks, and by chemically polishing the negative electrode current collector in advance, oxides and dirt are removed from the current collector surface and the surface is smoothed, resulting in a gel-like surface. The purpose is to provide a mercury-free alkaline battery that forms a uniform curved lead plating layer on the surface in contact with zinc, does not deteriorate heavy load performance, and generates little hydrogen gas during storage or at the end of discharge. There is.

Hereinafter, the present invention will be explained based on the drawings.

The figure is a sectional view showing the structure of the mercury-free alkaline manganese dry battery of the present invention. In the figure, 1 is an iron container whose entire surface is nickel-plated and also serves as a positive terminal. 2 is a positive electrode mixture formed by adding graphite as a conductive agent to manganese dioxide. 3 is a separator, 4 is 11I oxide] lead is dissolved M
This is a gelled zinc negative electrode made by dispersing mercury-free curved lead powder together with a gelling agent in the alkaline solution. Reference numeral 5 denotes a negative electrode current collector made of brass, which has been previously subjected to chemical polishing treatment to remove oxides and dirt on the surface and to form a smooth surface. 6 is a negative electrode metal terminal which is in contact with the negative electrode current collector 5. 7
The battery is constructed by insulating between the iron container 1 and the 9-pole metal terminal 6 with a packing, and sealing the gap therebetween.

Methods for surface polishing of the negative electrode current collector 5 include mechanical polishing, electrolytic polishing, etc. in addition to chemical polishing, but these polishing methods do not provide a uniform and smooth surface that is less likely to generate hydrogen gas. Also, the workability is poor, so a chemical polishing treatment is adopted, using hydrogen peroxide/sulfuric acid-based polishing liquid.

Next, the Example battery LR-5 of the present invention will be compared with a conventional product of the same type.

The negative electrode current collector used in the optical drum of the present invention was polished at room temperature by a chemical polishing solution containing 10 moles of hydrogen peroxide and 0.45 moles of sulfuric acid.
After processing for several minutes, the surface is chemically polished by repeating water washing, neutralization, and water washing. An LR-6 type alkaline manganese dry battery using this nine-electrode current collector and a gelled mercury-free zinc negative electrode was produced as a prototype product (A) of the present invention. Also, Kagakuken 7y
A conventional product CB) was also prototyped using a negative electrode current collector that had not been subjected to the above treatment, but in the same manner as above. [A], [B] Measured the 1Ω continuous discharge duration of 50 pieces each at the initial stage and after storing them at 45°C for 11 months, calculated the average value, and set the initial value of the invention product [A] as 100. The comparison results are shown in Table J.

Table 1 Also, for each of 20 batteries [A) and (B),
An undischarged battery and a battery discharged for 5 hours at 10Ω were tested for 60'
The amount of gas (ml) generated within the container was measured after 10, 20 and 30 days, and the average values are shown in Table 2.

Table 2 As is clear from Table 1, the product of the present invention (A) had better performance than the conventional product [B] using a negative electrode current collector that was not subjected to chemical polishing treatment, both at the initial stage and after storage for one month at 45°C. It can be seen that the [Ω] continuous discharge performance at 20°C is excellent.

Furthermore, as is clear from Table 2, the present invention product [A] is different from the conventional product [A].
B], undischarged and after 5 hours of 10Ω discharge, 60℃ (
It can be seen that the amount of gas generated within the battery was small when stored for 110 days, 20 days, and 30 days.

This is thought to be due to the presence of oxides, dirt, etc. on the surface of the negative electrode current collector of the conventional product [B), which creates resistance, deteriorates heavy load characteristics, and causes outgassing.

Therefore, the reason why the product [A] of the present invention has excellent heavy load discharge performance and generates little gas during undischarged and post-discharge storage is that the chemically polished negative electrode current collector surface
This is because it has a uniformly smooth surface and is evenly plated with zinc.

Also, since there is no mercury added, there is no need to worry about pollution.

As described above, the mercury-free alkaline battery using the negative electrode current collector subjected to the chemical polishing treatment of the present invention is excellent in that its heavy load characteristics do not deteriorate during storage and the amount of gas generated is not small. .

[Brief explanation of drawings]

The figure is a cross-sectional view of an LR6 type alkaline manganese dry battery, which is an example of the present invention. 1... Container 2. Positive electrode mixture 4... Zinc square frame 5... Name of current collector patent applicant

Claims (1)

[Claims] A battery using a positive electrode mixture consisting of manganese dioxide, silver oxide, etc., a mercury-free zinc negative electrode, and an alkaline electrolyte, characterized in that the current collector of the mercury-free zinc negative electrode is subjected to chemical polishing treatment. Mercury-free alkaline battery.