JPS59867A - Mercury cell - Google Patents

Abstract

PURPOSE:To prevent a voltage drop due to an increase of impedance of manganese dioxide, by using a material, in which nonfiring electrolytic manganese dioxide and firing electrolytic manganese dioxide are added to mercury oxide, as a positive electrode active material. CONSTITUTION:Nonfiring electrolytic manganese dioxide, firing electrolytic manganese dioxide and a conductive agent or the like are mixed in mercury oxide to form a positive electrode active material in a mercury cell. This positive electrode active material, zinc negative electrode and a caustic alkali electrolyte are used to build the mercury cell. In this mercury cell, a voltage drop due to an increase of impedance of firing manganese dioxide at an electric discharge can be prevented.

Description

[Detailed description of the invention] The present invention relates to anode active materials for mercury batteries.

The purpose of this is to prevent a drop in battery pressure during initial discharge at low temperatures.

Conventionally, this type of mercury battery has been manufactured by, for example,
As shown in Japanese Patent No. 095, it is stated that unfired electrolytic manganese dioxide is used alone as mercury oxide. In this case, the nominal voltage of WAe mercury alone is 1.3 or 1.35 V, but when unfired electrolytic manganese dioxide is added, it is 1.50 V Ic fx
Actual no-load voltage 11: 1.34V to 1.36V
1.45 to 1.50V.

However, in this conventional battery, the amount to be added is 5 to 15 wt.
%, and due to the small amount added, it is 1.3% for mercury batteries.
The voltage suddenly drops to v.

In order to improve the above-mentioned drawbacks, there is a method in which calcined electrolytic manganese dioxide such as β-MnO is added alone to mercury oxide by heat treatment at 350°C. In this conventional example, by adding 10 to 15%, the initial voltage was approximately 1.35 to 1.37, which approximated the nominal voltage of the mercury battery.
V range.

Comparing the two conventional mercury batteries mentioned above under the condition of continuous discharge with a load resistance of Ω at a low temperature of 0°0, the one with unfired electrolytic manganese dioxide added has an initial voltage of 1.5
0 V drops to 1.30 V within 1 hour.

On the other hand, with calcined electrolytic manganese dioxide added, 1.3
There is a drawback that the initial voltage of 0 V is higher than the discharge voltage, and the internal impedance increases due to the consumption of calcined electrolytic manganese, resulting in a sudden drop in voltage.

Therefore, in the present invention, zinc is used as a cathode, caustic alkali is used as an electrolyte, and a positive electrode active material in which manganese dioxide is added to mercury oxide is used in a mercury battery. , by adding calcined electrolytic manganese dioxide, the increase in impedance that occurs when calcined monolytic manganese dioxide is added alone to mercury oxide can be reduced by adding both uncalcined electrolytic manganese dioxide and calcined electrolytic manganese dioxide to mercury oxide. By adding it in advance, it is possible to prevent a voltage drop due to an increase in impedance of calcined manganese dioxide during discharge, and to increase the voltage during initial discharge to 1.
Since the voltage starts from 40V, it approximates the voltage of a mercury battery, eliminating the noise of the hearing instrument, and as a result, the above-mentioned drawbacks can be solved.

An embodiment of the present invention will be described below.

1 is an anode active material containing 80]i parts of mercury oxide, 9 parts by weight of uncalcined electrolytic manganese dioxide, 6 parts by weight of calcined electrolytic manganese dioxide fired at 300° to 350°0, and 4 parts by weight of mercury oxide.
A mixture obtained by uniformly stirring and mixing five scaly graphite stacks for cutting is formed into a pellet, and the pellet is filled under pressure into a metal container 2 made of a drawn nickel-plated steel plate or stainless steel. 3 is a separator placed on the upper surface of the anode active material 1.

4 is natural fiber and synthetic, iii! Made from non-woven fabric mixed with fiber and T.

This is an electrolyte holding material. Reference numeral 5 denotes a metal cap with a copper layer formed on its inner surface, and the inside thereof is filled with a gel cathode 6 made of a mixture of salivary lead powder, polyacrylate as a gelling agent, and an alkaline electrolyte of caustic potash or caustic soda. Metal container?
) 1 and the metal cap 5 are connected via an insulating backing 7,
The opening of the metal container 2 is bent inward and sealed to form a mercury battery.

FIG. 2 shows the results of measuring the duration of the mercury oxide battery of the present invention obtained in the above example.

As can be seen from this figure, in the battery of the present invention, the open circuit voltage is 1.40V, which is an intermediate potential between that of the conventional battery with the addition of fired electrolytic manganese dioxide and that of the battery with the addition of unfired electrolytic manganese dioxide. The discharge curve (Al) approximates 1.3 V after the start of discharge, and the increase in impedance when used alone with baked electrolytic manganese dioxide is canceled out by the addition of unburned electrolytic manganese dioxide, resulting in a sudden increase in voltage. It shows a discharge curve with no change.

Incidentally, in order to clarify the effects of the present invention, we will introduce a conventional battery [B1] in which mercury oxide and calcined electrolytic manganese dioxide were mixed alone, and a conventional battery TC' in which mercury oxide and uncalcined electrolytic manganese dioxide were solely mixed. 1 and 2 have the compositions of the anode active materials shown below, and the other battery components were assembled in the same manner as those described in the examples of the present invention, and the results were measured under the same discharge conditions. .

Conventional battery a fBl Conventional battery (C'l mercury oxide
80 80 Calcined electrolytic manganese dioxide 15 0 Uncalcined electrolytic manganese dioxide
0 15 Phosphorous graphite 55 @2 As can be seen from Figure 2, in the product of the present invention, by adding calcined electrolytic manganese dioxide, uncalcined relaxed manganese dioxide, and total mercury oxide, the open circuit voltage can be increased to 1 by adding calcined manganese dioxide. .40 V, which approximates that of a mercury battery, and also provides a gentle IE curve, similar to when unfired electrolytic manganese dioxide is added alone.
No sudden voltage drop will occur.

Furthermore, by adding unfired electrolytic manganese dioxide, the increase in internal impedance at the initial stage of discharge, which occurs when calcined electrolytic manganese dioxide is added uniformly, does not occur due to the addition of unfired electrolytic manganese dioxide. , it is possible to provide an industrially valuable mercury battery that can overcome the drawbacks of conventional batteries.

[Brief explanation of the drawing]

The first factor is a cross-sectional view of the mercury battery of the present invention, and FIG. 2 is a curve diagram of the product IA of the present invention and conventional batteries (B) and (C). 1 Anode active material 2 Metal container 3 Separator 5 Metal cap 6/gel pole

Claims (1)

[Claims] Zinc TM electrode, caustic alkali as electrolyte, mercury oxide,
A mercury battery using a positive electrode active material to which manganese dioxide is added, characterized in that the positive electrode active material is made by adding unfired electrolytic manganese dioxide and fired electrolytic manganese dioxide to mercury oxide.