JPS58192264A - Alkaline manganese battery - Google Patents

Abstract

PURPOSE:To substantially increase discharge performance by specifying molding pressure and compression density of a positive mix prepared by mixing manganese dioxide and conductive material. CONSTITUTION:In an alkaline manganese battery comprising a negative electrode using zinc as an active mass and a positive mix prepared by mixing conductive mass to manganese dioxide which is an active mass, molding pressure of the positive mix is 0.3-1.5t/cm<2> and compression density of the positive mix containing only manganese dioxide and conductive material is 2.5-2.9g/cm<3> on a dry basis. When molding pressure is more than 1.5t/cm<2> especially 3t/cm<2> or more, discharge performance is almost same as that of conventional alkaline manganese battery. When molding pressure is less than 0.3t/cm<2>, discharge performance is substantially decreased. The positive mix obtained by above mentioned molding pressure has a compression density of 2.5-2.9g/cm<3> on a dry basis of only manganese dioxide and conductive mass. The alkaline manganese battery using the positive mix having this range of compression density shows the best discharge performance.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an alkaline manganese battery, and more specifically, the discharge characteristics are dramatically improved by specifying the molding load and compression density of a positive electrode mixture containing manganese dioxide and a conductive material. Regarding alkaline manganese batteries.

Alkaline manganese batteries have better discharge performance, especially under continuous heavy loads, than conventional Lecrancier type dry batteries and zinc chloride type dry batteries, so cylindrical alkaline manganese batteries have recently been commonly used in 1m1m Votaple electric batteries. Although button-shaped alkaline manganese batteries are smaller than silver and mercury batteries in terms of electrical manufacturers, the number of manufacturers is rapidly increasing due to the soaring price of silver, as they are cheap batteries.

The positive electrode of an alkaline manganese battery is generally made by mixing manoganese dioxide, which is an active material, and scaly black ship, which is a conductive material, and then molding the mixture.

For Lecrane type dry batteries and zinc chloride type dry batteries,
In order to prevent the potential from decreasing due to fluctuations in the positive electrode mixture during discharge, it is necessary to increase the field buffering capacity, and therefore the molding load is suppressed to about several tens of thousands.

On the other hand, in alkaline manganese batteries, the electrolyte is a strongly alkaline caustic potassium aqueous solution, and there is no need to consider any fluctuations near the positive electrode mixture during discharge, so the amount of liquid in the positive electrode mixture can be small. A molding method has been adopted to increase the compaction density of the mixture on the IIE side, and conventionally it was thought that it would be better to increase the molding pressure for this purpose (the normal molding load at the end was 317 ~ In this case, the compressed density of the positive electrode mixture was usually 2.997 or more.

However, alkaline manganese batteries formed using this method and having the above-mentioned compressed density are used as N sources for portable televisions, tape recorders, etc., which have heavy loads, and in recent years there has been a demand for higher performance. However, it does not necessarily satisfy this requirement.

In response to such demands, the present invention aims to provide an alkaline manganese battery with improved discharge performance.

As a result of research in line with this objective, the present inventors focused on the conventionally common method of molding the positive electrode mixture, in particular the molding load, and reduced the molding load from the conventional value and compressed the positive electrode mixture. The present inventors have discovered that by lowering the density, the electrolytic solution permeates into the positive electrode mixture sufficiently, and the discharge characteristics are rather significantly improved.

That is, the present invention provides an alkaline manganese battery having a negative electrode containing zinc as an active material and a positive electrode mixture containing manganese dioxide as an active material and a mixture of C and C material, wherein the positive electrode mixture comprises: An alkaline manganese battery characterized by having a forming load of 0.3 to 1.5 tA and a compressed density of 2.5 to 2.99/l, d on a dry basis containing only manganese dioxide and a conductive material. be.

The molding load of the positive electrode mixture of the alkaline manganese battery of the present invention is 0.3 to 1.5 t/cd, and when it exceeds 1.5 t/i, the discharge performance is different from that of conventional alkaline manganese batteries that are molded with a molding load of 31 A or more. There is no difference. Also, 0.31
If it is less than /i, the discharge performance will be significantly inferior.

In addition, the positive electrode mixture obtained under the molding load in the above range is
2. Dry base with only manganese dioxide and conductive material.
An alkaline manganese battery having a compressed density of 5 to 2.997 and using a positive electrode mixture having a compressed density in this range has the best discharge performance.

The alkaline manganese battery of the present invention as described above
[For example, AA size alkaline manganese
□In a battery, if the discharge duration in the case of conventional molding load is 100, it can be obtained with the molding load according to the present invention.
The advantages brought about by the present invention in actual processes, such as the reduction of impurities associated with this, are even greater.

The present invention will be specifically described below based on F1 examples and comparative examples.

Examples 1 to 3 and Comparative Examples 1 to 6 Tests were conducted using the alkaline manganese batteries shown in the first example. The alkaline manganese battery shown in Fig. 1 is composed of a positive electrode can 1, a positive electrode 2, a separator 3, a negative electrode 4 made of gelatinized zinc powder with carboxymethyl cellulose, a negative electrode current collector 5, a rubber packing 6, and a holding plate. . This positive electrode 2 is made by mixing 88 parts by weight of electrolytic manganese dioxide with 12 parts by weight of scaly black ship as a conductive material, and adding 40% KOH'f
An electrolytic solution saturated with ZnO was added to the Il solution, and the thoroughly kneaded mixture was molded under the molding load shown in Table 1 for Mli.

The alkaline manganese battery obtained in this way was
Discharge is performed at C with a load resistance of 4Ω, and the sustaining voltage is 0.
Comparative example 6 as a result of measuring the discharge duration until 9■
is shown in Table 1 and Figure 2 as an index with 100. Further, FIG. 3 shows the relationship between the molding load and compressed density of the positive electrode mixture.

As shown in Table 1 and FIG. 2, the discharge performance of Examples 1 to 3 is dramatically improved compared to Comparative Example 3 using the conventional molding load. However, in Comparative Example 1, in which the molding load was extremely low, the discharge performance deteriorated.

Further, Comparative Example 2, which has a slightly lower molding load than Comparative Example 6, does not show much difference in discharge performance from Comparative Example 3.

In addition, when the compressed density of the positive electrode mixture is shown on a dry basis of only manganese dioxide and conductive material, it is as shown in Figure 16 when burned under the molding load. It can be seen that the manganese battery has significantly better discharge performance than the conventional alkaline manganese battery, which has a higher compressed density.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of an alkaline manganese battery used in Examples and Comparative Examples of the present invention, FIG. 2 is a diagram showing the relationship between the molding load (t/clI) of the positive electrode mixture and the discharge duration (index), and Fig. 3 is a diagram showing the relationship between the molding load (t/i) and compressed density (9/crn'') of the positive electrode mixture. 1: positive electrode can, 2: positive electrode, 3: separator, 4: frozen zinc powder negative electrode gelled with carboxymethylcellulose, 5: negative electrode current collector, 6: rubber panoquin, 7: holding plate.Patent applicant: Mitsui Mining & Mining Co., Ltd., patent attorney: Tatsu Ito Yui Tetsu Higashi Shimae) Fig. 3 84 U":)°Up (1) Yo) 4 Continued Sode 11 Yo Ill pull 1j)'7i15月2811 1"Ime11goodl Island l116 Itsuki-dono1.4If
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Name of Party - #1 Metal Mining Co., Ltd. d Representative 8 8 Setsu Shima Male 4 Representative 〒105 b, Supplement 1■Order 1] Subject of voluntary amendment 6, Supplement 11 "Claims column in the 18th century! ” 7. Amend the scope of claims in the supplementary row as shown in the attached sheet. Scope of claims

Claims (1)

[Claims] 1. An alkaline manganese dry battery having a negative electrode containing zinc as an active material and a positive electrode mixture containing manganese dioxide as an active material mixed with a conductive material, the positive electrode mixture having a molding load of 0.3 to 1.517-, and the compressed density is 2.5 to 2.5 on a dry basis containing only manganese dioxide and conductive material.
2.997- an alkaline manganese battery.