JPS59103279A - Silver oxide battery - Google Patents

Abstract

PURPOSE:To suppress variation in the discharge capacity of a silver oxide battery by restricting the discharge capacity through silver oxide or silver peroxide which is contained in the positive electrode and the packed quantity of which can easily be controlled. CONSTITUTION:A button-type silver oxide battery is constituted of the following members: a positive electrode 2 principally consisting of silver oxide; a separator 3 consisting of cellophane, polyethylene formed by graft polymerization and an absorbing nonwoven-fabric member; and a negative electrode 6 consisting of amalgamated zinc, a gelling agent and electrolyte. In such a battery, when the quantity of zinc which can react with whole silver oxide and/or silver peroxide which give the discharge capacity of the positive electrode 2 is supposed to be 100, a quantity corresponding to 100-110 of zinc is used as amalgamated zinc. In addition, the electric capacity of packed amalgamated zinc is adjusted to 101-110% of the electric capacity of packed oxide and/or silver peroxide. As a result, restriction of the positive electrode 2 as well as improvement of the preservation characteristic of capacity are secured.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a silver oxide battery, and more particularly to a silver oxide battery with improved discharge capacity variations.

It is widely used in small electronic devices such as electronic desktop calculators.

In recent years, the development of these electronic devices has been remarkable, and they are becoming smaller and thinner. Along with this, many of the batteries used are becoming smaller or thinner and have lower capacity.

When evaluating batteries with small capacities, variations in capacity have become a problem. In other words, in the case of a battery with a small capacity, even if the absolute amount of variation in capacity of each individual battery is the same as that of a battery with a large capacity, the ratio of the variation amount to the center value of capacity is inversely proportional to the center value of capacity, so the capacity The smaller the battery, the larger the ratio of the amount of variation. As a result of investigating this variation in capacity, it was found that it was largely due to variation in the amount of active material filled during battery manufacture.

Incidentally, in a typical silver oxide battery, the negative electrode is formed in a gel form from zinc hydride, a gelling agent such as carboxymethyl cellulose or sodium polyacrylate, and an alkaline electrolyte. Further, the positive electrode is constructed by filling a pellet-like material formed by powder molding from silver oxide, graphite as a conductive agent, acetylene black, etc. Conventionally, in order to prevent hydrogen gas from being ordered during overdischarge, batteries have been designed to have an excessive capacity on the positive electrode side, and to use negative electrode regulation in which the capacity of the battery is regulated by the capacity on the negative electrode side. Therefore, variations in the discharge capacity of the batteries were largely caused by variations in the amount of zinc hydride filled in the negative electrode. However, since the negative electrode is filled with a gel-like material as described above, it is difficult to control the filling amount at the time of filling, and large variations in the filling amount are inevitable.

This invention has been achieved in view of the above-mentioned points, and provides a silver oxide battery with improved variation in discharge capacity.

In other words, the silver oxide battery of the present invention has a positive electrode active material mainly composed of silver oxide and/or silver peroxide, an electrolyte, and a negative electrode active material mainly composed of zinc oxide, and the above-mentioned The present invention relates to a silver oxide battery characterized in that the filling capacitance of zinc oxide corresponds to 100 to 110% of the filling capacitance of the silver oxide and/or silver peroxide.

In the silver oxide battery of the present invention, silver oxide, silver peroxide, or a mixture thereof can be mainly used as the positive electrode active material. This positive electrode active material also contains an auxiliary material that discharges at a much lower potential than silver oxide or silver peroxide.
Good too. When such an auxiliary material is mixed, when there is an excess of zinc, the remaining zinc that has not been completely discharged in the area of use can be completely discharged at a low potential. Therefore, it is possible to prevent the electrolytic solution from being electrolyzed and generating hydrogen gas during overdischarge. In this case, the above-mentioned auxiliary material preferably has a filling electric capacity greater than or equal to the excess discharge capacity of the zinc oxide, and has a proportion of 10 to 20% by weight relative to 80 to 90% by weight of silver oxide and/or silver peroxide. It is more preferable that the mixture can be completely mixed. Further, as this auxiliary material, cadmium oxide CdO can be exemplified.

In this invention, the filling capacitance of frozen zinc in the negative electrode is 1 of the filling capacitance of silver oxide and/or silver peroxide in the positive electrode.
It can be regulated from 00% to 110%. In other words, if the amount of zinc that completely reacts with silver oxide and G' or silver peroxide that gives the discharge capacity of the positive electrode is 100, then 100 to 1
An amount of zinc equivalent to 10% is used as zinc hydrate. It is generally preferable that the filling capacitance of zinc hydride is 101 to 110% of the filling capacitance of silver oxide and/or silver peroxide. By doing so, it is possible to reliably improve positive electrode regulation and capacity storage characteristics, as described below.

By configuring as described above, in the silver oxide battery of the present invention, the discharge capacity of the battery can be regulated by the positive electrode, which is regulated by the silver oxide and/or silver peroxide of the positive electrode. Since it is easy to suppress variations in the amount of silver oxide and/or silver peroxide in the positive electrode,
As a result, it is possible to reduce variations in battery discharge capacity.

In this invention, by making the filling capacitance of zinc oxide larger than the filling capacitance of silver oxide and/or silver peroxide, storage characteristics of discharge capacity, such as capacity deterioration after storage and capacity It is possible to improve the variation in Capacity deterioration and variation in capacity after storage are often caused by zinc passivation.

In this invention as well as in the conventional case, passivation of zinc occurs during storage. However, since the capacity of conventional batteries was determined by the amount of zinc, passivation of zinc had a direct impact on battery capacity. On the other hand, in the battery of the present invention, the capacity is determined by the amount of silver oxide and silver peroxide, so even if zinc has no effect. Therefore, the storage capacity of the capacity in terms of the used area can be made better than in the past.

The electrolytic solution that can be used in this invention may be any conventionally known electrolytic solution, such as a KOH aqueous solution. Furthermore, conventionally known components can be used as other components of the silver oxide battery according to the present invention. For example, the positive electrode can use the above-mentioned positive electrode active material and a co-wind conductive agent such as graphite or acetylene black, and the negative electrode can contain a gelling agent, electrolyte, etc. in addition to zinc hydrate. It's fine.

Further, the silver oxide battery of the present invention has the same discharge voltage and flatness as the conventional one, and maintains the features and advantages of the conventional silver oxide battery.

Therefore, in actual use, even devices that have been designed to accommodate conventional batteries can be used in the same manner as before.

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows an example of the configuration of a conventionally known button-type silver oxide battery to which the present invention can be applied.

The silver oxide battery shown in FIG.
2), separator (3) made of cellophane, graft-polymerized polyethylene, and nonwoven absorbent material, sealing gasket (4) made of nylon, negative electrode case (5) made of three-layer cladding of copper, stainless steel, and nickel, and zinc hydrate. It consists of a negative electrode (6) composed of a gelling agent and an electrolyte, and has a diameter of 9.5 mm.

The height is 2.6 mrn. In battery A according to the invention, 0.28 g% powder consisting of 6 parts by weight 5 tons/cm
A powder molded product was used. And for the negative electrode (6),
A gel-like mixture of zinc hydrate, a gelling agent, and an aqueous KOH solution was filled. Note that the filling electric capacity of this frozen zinc was made to correspond to 108% of the filling electric capacity of silver oxide of the positive electrode. A conventionally known battery B using a KOH aqueous solution as an electrolyte was used as a comparative example with the present invention. In this battery B, 0.27 g of a powder consisting of 100 parts by weight of silver oxide and 6 parts by weight of graphite was used as the positive electrode, and the negative electrode was filled with the silver oxide of the positive electrode. A gel-like mixture of frozen zinc, a gelling agent, and an aqueous KOH solution having a filling capacitance corresponding to 90 g of capacitance was filled.

For these batteries A and B, immediately after manufacture and 6CIC
A discharge test was conducted under the conditions of a load of 6.5 and Ω after storage for 20 days at a temperature of 60 tl' and after storage for 40 days at a temperature of 60 tl'. Figure 2 shows battery A of this invention and battery A of this invention. The discharge curve of Next Pond B is shown. In the case of battery A of this invention,
The region where the discharge voltage is 1.55 V corresponds to the discharge between silver oxide and zinc, and the region where the discharge voltage is 0.45 V corresponds to the discharge between CdO and zinc. Final voltage 1.30V
In this case, the discharge capacity can be regulated by silver oxide. Table 1 shows the average value and standard deviation of the discharge capacity of Battery A of the present invention under each storage condition, and the final voltage F! :1.3
The cases where the voltage is 0 V and 0.40 V are shown. Further, Table 2 shows the average value and standard deviation of the discharge capacity of the conventional battery B under each storage condition when the final voltage % was 1.30 V.

From Tables 1 and 2, it is clear that the dispersion in the discharge capacity of batteries regulated with silver oxide is much smaller than that of battery B, which is regulated with zinc. It is. It is also shown that the discharge capacity of battery A, which is regulated by silver oxide, has a smaller capacity deterioration after storage for a long time.

As described above, in the silver oxide battery of the present invention, the discharge capacity is regulated by the silver oxide and/or silver peroxide of the positive electrode, which makes it easy to control the filling amount, so that variations in the discharge capacity can be suppressed. However, silver oxide and silver peroxide are relatively expensive, but since the silver oxide and silver peroxide used in this invention's silver oxide battery can be utilized to the maximum, it can be produced in smaller quantities and at lower cost than before. can.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal cross-sectional view of a conventionally known Buttonya silver oxide battery to which the present invention can be applied, and FIG. 2 is a graph showing discharge curves of the silver oxide battery according to the present invention and the conventional silver oxide battery. It is. In addition, in the symbols used in the drawings, (1)・・・・・・・・・・・・ Positive electrode case (2
)・・・・・・・・・・・・Positive electrode (31・・・・
・・・・・・・・・・・・Separate Lake (4)・・・・・・
・・・・・・・・・Sealing gasket (5)・・・・・・
・・・・・・・・・Negative electrode case (6)・・・・・・・・・
・・・・・・It is a negative electrode. Agent Masaru Saturn

Claims (1)

[Claims] It has a positive electrode active material mainly composed of silver oxide and silver peroxide, an electrolytic solution, and a negative electrode active material mainly composed of zinc hydride, and the filling electric capacity of the zinc hydrate or the above 100-110% of the filling capacitance of silver oxide and 7 years old or silver peroxide
7i: Characteristics of silver oxide batteries.