JPS60167260A - Alkaline battery - Google Patents

Abstract

PURPOSE:To increase the discharge capacity of an alkaline battery and enable it to be preserved for a longer period of time by pressing and fitting a mixture pellet composed of granulated silver peroxide and a silver peroxide powder into a positive case and forming a reduced layer having a restricted apparent density and thickness on the negative-electrode-side surface of the thus formed body. CONSTITUTION:A positive active material 2 consisting of a mixture of granulated silver peroxide (A) and a silver oxide powder (B) is compressed and molded into a given shape and the molded mixture is airtightly fitted into a positive case 1. Next, a reduced layer (C) with an apparent density of at least 5.5g/cm<2> and a thickness of at least 10mu is formed on the negative-electrode-4-side surface of the positive mixture. After that, the thus obtained body is installed facing a negative electrode 4 with a separator 3 impregnated with electrolyte interposed before sealing is performed using a gasket 6, thereby constituting an alkaline battery. As a result, due to the synergistic effect of the thickness and the apparent density of the reducing layer (C), the discharge capacity of the battery is increased and the battery can be preserved for a longer period of time.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a high-performance alkaline battery, and its object is to provide a battery having a silver oxide potential, a large discharge capacity, and excellent long-term storage performance.

In recent years, silver oxide batteries have been widely used as batteries for small portable electronic devices, but recently silver peroxide, which has a higher discharge capacity per unit volume than silver oxide, has been used alone as a positive electrode active material, or silver peroxide has been used alone as a positive electrode active material. The use of granulated silver oxide powder mixed with silver oxide powder is being considered. However, a battery using silver peroxide as the positive electrode active material has two stages: a voltage of 1.8 V at which silver peroxide is reduced to silver oxide, and a voltage of 1.5 V at which silver oxide is reduced to silver. Therefore, there was a problem with compatibility with silver oxide batteries. In order to have compatibility with silver oxide batteries, the battery voltage was changed from silver oxide to silver by 1.5■
There is a need to control the temperature of the air, and many proposals have already been made for this purpose. In principle, silver peroxide, which is the positive electrode active material, is prevented from coming into direct contact with the positive electrode container, which also serves as the positive electrode terminal. There is a method of coating the pellet by providing a reducing layer on its entire surface, or filling a positive electrode container with a mixture of silver peroxide granules and silver oxide powder, and oxidizing the surface facing the negative electrode with a TA solution containing a reducing agent. A method of controlling voltage by providing a reduction layer made of a mixture of silver and silver has been widely used.

However, with the above conventional method, unevenness occurs in the reduction layer, and even if voltage control is possible immediately after manufacture, 1.8V of silver peroxide → silver oxide may be generated after long-term storage, resulting in sacrificing IT battery capacity. This was prevented by increasing the thickness of the reduced layer to several tens of percent of the positive electrode capacity.

In order to solve the above-mentioned drawbacks, the present invention aims to solve the problem that the positive electrode active material is made of a mixture of silver peroxide granules and silver oxide powder, and the negative electrode is made of a mixture of silver peroxide granules and silver oxide powder. In the case of an alkaline battery in which a reduced layer is formed only on the facing surface, this was done by focusing on the fact that the thickness and apparent density mutually influence each other. In the cross-sectional view of the alkaline battery according to the invention, 11 is a positive electrode container that also serves as a positive electrode terminal, 2 is a positive electrode active material, 3 is a seventh pallet, 4 is a negative electrode active material, 5 is a negative electrode container that also serves as a negative electrode terminal, and 6 is a sealant gasket. . A positive electrode active material 2 made of a mixture of silver peroxide granules A and silver oxide powder B is pressure-molded into a predetermined shape, and is press-fitted into the positive electrode container 1 and tightly attached thereto.

Furthermore, a reduction layer C is formed on the surface facing the negative electrode by regulating the thickness h and apparent density d, a separator 3 is placed thereon, and a negative electrode container 5 filled with a negative electrode active material 4 is placed on the positive electrode container 1 along with a gas sealant 6 as a sealant. It is crimped.

The diameter produced by controlling the thickness h and apparent density d of the reduced layer 0 as described above is 7. Table 1 shows the results of investigating the long-term storage performance of alkaline batteries with external dimensions of 1.6 mm in height.0 From Table 1, even if the thickness of the reduced layer is the same, the apparent density can be increased. As a result, it can be seen that long-term storage performance is improved. To explain the results in Table 1 in more detail, A3,
If the apparent density of the reduced layer is 4.5974, such as in A4, the reduced layer will crack during the subsequent pressurization process, making it impossible to control the battery voltage after long-term storage of 3 to 6 months or more.

Also A5. As in A9, the apparent density of the reduced layer is s and s, respectively.
The same thing applies even if the thickness of the reduced layer is too small even if it is 9/d or 6.59/cd. From the above, it is found that in Alka IJ using a mixture of silver peroxide granules and silver oxide powder as the positive electrode active material, the apparent density of the reduced layer is 5.59/d or more and the thickness is 10 μ or more. It becomes necessary.

Next, the discharge characteristics were compared, and the results are shown in FIG. In Figure 2, B) is the A6 battery of the present invention in Table 1, (
B) has the same positive electrode active material as the battery of the present invention and has a reduction amount of 5.
s mm H/c-, (C) is a battery when only silver oxide is used as the positive electrode active material, each 5ooooΩ.
Discharge was performed with a load resistance of . From Figure 2, the discharge duration is 860 hours for battery P) and 82 hours for battery (B).
0 hour, and battery (C) for 620 hours, when a reduced layer is formed on the surface facing the negative electrode as in the battery of the present invention, it is better to control both the apparent density and thickness of the reduced layer than to control the amount of reduction. It can be seen that it has a large value and has excellent long-term storage performance.

As described above, the alkaline battery of the present invention has a large discharge capacity and excellent long-term storage performance compared to conventional batteries.
It is most suitable for use in small IJJl portable electronic devices in recent years, and its industrial value is great.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of the alkaline battery of the present invention, and FIG. 2 is a discharge characteristic diagram. 1...Positive & A container 2...Positive electrode active material 3...7 palate 4...Negative electrode active material 5...Negative electrode container 6...
・Sealing agent gasket Tom...Peroxide m granules B...Silver oxide powder O...Reduction layer Applicant Yuasa Battery Co., Ltd. Discharge voltage CV) 200 400 600 800 1.000 Discharge time (hours)

Claims (1)

[Claims] A pellet of a mixture of pressure-molded silver peroxide granules and silver oxide powder is press-fitted into a positive electrode reactor, and a reduction layer with an apparent density of 5,597 c++f and a thickness of 10 μ or more is formed on the surface facing the negative electrode. 1. An alkaline battery characterized in that a negative electrode container filled with a negative electrode active material is press-bonded to a positive electrode container together with a sun-resistant gasket, with a seven-part plate formed and infiltrated with an electrolytic solution interposed therebetween.