JPS5947864B2 - Flat primary alkaline battery - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a flat primary alkaline battery with an improved anode.

Conventionally, this type of alkaline battery has sequentially housed an anode made of a nickel oxide mixture, a separator holding an electrolyte such as caustic potash, and a cathode made of gelled zinc in a nickel cylindrical container that also serves as an anode terminal. , and the upper end opening of the container is sealed with an insulating material interposed therebetween by a metal lid that also serves as a cathode terminal.

This flat primary alkaline battery has excellent high-load characteristics, so it is widely used in battery-applied devices that require large currents and instantaneous power. However, since this battery uses an expensive nickel oxide mixture for the anode, there is a problem of rising costs. In consideration of economic efficiency, a flat primary alkaline battery has been proposed in which a mixture of a nickel oxide mixture and an inexpensive manganese dioxide mixture is used as an anode.

However, when discharging this battery, the nickel oxide, which has a high electrode potential, discharges first, and then the manganese dioxide, which has a low electrode potential, discharges, resulting in a two-stage discharge curve, which causes significant fluctuations in the battery voltage. Therefore, it cannot be used as a battery-applied device. In view of this, the inventor of the present invention has conducted various studies in order to solve the above-mentioned problems, and as a result, a manganese dioxide mixture is placed around the inside of a nickel cylindrical container that also serves as an anode terminal, and the central part of the nickel cylindrical container is By disposing a nickel oxide mixture to form an anode, an extremely inexpensive flat primary alkaline battery with excellent discharge characteristics and no two-stage discharge curve was discovered. The reason why a nickel oxide mixture was used as a component of the anode is as follows. In other words, as an active material with a higher potential than the manganese dioxide mixture,
There are Ag2O, Ag0, etc., but since these active materials dissolve in alkaline electrolysis, they either cause capacity deterioration or deposit on the separator, damaging the separator and causing a short circuit. On the other hand, nickel oxide mixture (Ni0O
H) has a higher potential than the manganese dioxide mixture, and unlike Ag20, it does not dissolve in alkaline electrolyte, which can solve problems such as capacity deterioration. In the flat primary alkaline battery described above, the reason why the discharge curve does not become two steps as in the case where a mixture of a nickel oxide mixture and a manganese dioxide mixture is used as an anode is considered to be due to the following mechanism.

That is, by arranging a manganese dioxide mixture in a concave cross-section around the inner periphery and bottom of a nickel cylindrical container, and by arranging a nickel oxide mixture in the recess, the potential of the battery can be adjusted to the level of the container ( The rate is determined by the manganese dioxide mixture that causes the reaction of formula (1) below. Further, the nickel oxide mixture in the recessed portion of the manganese dioxide mixture causes the reaction shown in the following formula (2), and acts as an oxidizing agent on the manganese dioxide mixture.

Therefore, since the battery of the present invention is rate-determined by the potential of the manganese dioxide mixture, it is possible to prevent the discharge curve from becoming two stages unlike the conventional type in which two types of mixtures are mixed.

Moreover, the MnOOH generated by the above equation α1) is
) is oxidized by 0H- generated in the formula (1).
The reaction in the equation shifts to the left side and the MnOe state can be maintained for a long time, and the initial potential of the manganese dioxide mixture can be It becomes possible to maintain. Hereinafter, the present invention will be explained in detail with reference to the drawings.

In the figure, 1 is a cylindrical container made of nickel plated steel that also serves as an anode terminal, and an anode 2 is housed inside this container 1, and further includes a separator 3 and an electrolyte holding material 4 made of an alkali-resistant nonwoven fabric.
A cathode 5 is housed therein. Further, a metal lid 7 which also serves as a cathode terminal and whose lower end periphery is covered with an insulating packing 6 is fitted into the upper end opening of the container 1, and the upper end of the container 1 is bent inward and the packing 6 is fitted. The interior of the container 1 is hermetically sealed with a metal lid 7.
Therefore, in the present invention, as the anode 2, a manganese dioxide mixture 2a is arranged so as to have a concave cross section over the inner periphery and bottom of the cylindrical container 1 as shown in FIG. As shown, a nickel oxide mixture 2b is placed in the recessed portion and formed.

In this case, it is preferable to form the anode 2 by making the capacities of the manganese dioxide mixture 2a and the nickel oxide mixture Zb substantially equal. The manganese dioxide mixture is composed of manganese dioxide and a conductive agent such as acetylene black or flaky graphite, and the mixing ratio of manganese dioxide and the conductive agent is usually 85-90:15-10 by weight. The above-mentioned nickel oxide mixture is composed of nickel oxide and a conductive agent such as acetylene black or scale graphite, and the ratio of the nickel oxide to the conductive agent is usually 85 to 95 by weight.
:15-5.

The separator 3 may be a woven fabric or non-woven fabric made of synthetic resin fibers with excellent alkali resistance such as polyamide, polyethylene, or acrylonitrile monopinyl monochloride copolymer, or a polyvinyl alcohol solution and a boron-based compound ( For example, a sheet coated with a viscous mixture of boric acid, boron oxide, metaboric acid, etc.) or a metal oxide (magnesium oxide, calcium oxide, etc.) and dried is used.

The cathode 5 may be, for example, a disk-shaped press molded Yonghwa zinc powder, or a gelling agent of Yonghwa zinc powder and an alkali-resistant carboxyl type polymer (for example, carboxyvinyl polymer, sodium polyacrylate, etc.). Gel-like zinc obtained by mixing and stirring a medicinal solution such as caustic soda or caustic potash is used.

Next, embodiments of the present invention will be described with reference to the above-mentioned drawings.

Example First, an anode (1) and a cathode (1) were manufactured by the method shown below.

A manganese dioxide mixture having a composition of The mixture 2a is filled under pressure, and then the mixture 2a is filled as shown in FIG.
The manganese dioxide mixture 2a and the above-mentioned Futsukeru oxide mixture 2b having the same capacity as the manganese dioxide mixture 2a are filled under pressure into the concave portion a to obtain a discharge capacity of approximately 10.
An anode 2 of 0 mAh was formed.

A gelled zinc cathode was prepared by washing and uniformly mixing 70 parts by weight of a 3570 caustic potassium aqueous solution to 100 parts by weight of a mixed powder having the following composition.

Next, as shown in FIG. 1, a viscous substance of polyvinyl alcohol and magnesium oxide is applied to a polyamide woven fabric on the anode 2 in the positive can 1, and a dried sheet-like separator 3 and an electrolyte holding material 4 made of a polyamide nonwoven fabric are applied. The cathode 5 is sequentially housed through the positive can 1, and the upper end opening of the positive can 1 is sealed with a metal lid 7 through an insulating packing 6, thereby forming a JIS standard H-C type flat primary alkaline battery. did.

Comparative Example 1 The JIS standard H- A C-type flat primary alkaline battery was constructed.

Comparative Example 2 A J{SWH-C type flat primary alkaline battery was constructed in the same manner as in the above Example except that an anode having a discharge capacity of 100 mAh and consisting only of a manganese dioxide mixture having the above composition was used.

Thus, the primary alkaline batteries of Examples and Comparative Examples 1 and 2 were continuously discharged at 25° C. with a current of 5 mA until a current of 0.9 was reached, and the state of discharge over time was examined. The results are shown in the figure. In addition, the solid line A in the figure
is the discharge curve of the primary alkaline battery of Example, solid line B is the discharge curve of the primary alkaline battery of Comparative Example 1, and solid line C is the discharge curve of the primary alkaline battery of Comparative Example 2.
The discharge curve of a primary alkaline battery is shown. As is clear from the figure, the battery of the present invention (solid line A in the figure) has a lower battery voltage at the end of discharge compared to the battery of Comparative Example 2 (solid line C in the figure) which uses an anode made of only a manganese dioxide mixture. It can be seen that the energy density (Wh/d) of the battery per unit volume is high.

In addition, the battery of Comparative Example 1 using an anode made of a complete mixture of manganese dioxide mixture and nickel acid mixture (solid line B in the figure)
) has a higher energy density than the battery of Comparative Example 2, but the discharge curve is two-step b, and a fluctuation phenomenon of battery voltage is observed. On the other hand, in the battery of the present invention, the discharge curve does not have two stages, and the phenomenon of flat battery voltage fluctuation is not observed at all. As detailed above, the present invention is inexpensive and has excellent discharge characteristics, and has remarkable effects such as the fact that the discharge curve does not become two stages and can be effectively used as a power source for battery-applied equipment. .

[Brief explanation of the drawing]

FIG. 1 is a partially cutaway perspective view showing one form of a flat primary alkaline battery of the present invention, FIGS. 2 and 3 are cross-sectional views showing the process of forming an anode, and FIG. 4 is a battery of the present invention and a conventional battery. FIG. 2 is a diagram showing the relationship between discharge time and battery voltage for a battery. 1... Cylindrical container, (anode terminal), 2... Anode, 3
... Sebarator, 5... Cathode, 7... Lid body (cathode terminal).

Claims (1)

[Claims] 1 Place the anode,
In a flat battery having a structure in which a separator and a cathode are sequentially housed, and the upper end opening of the container is sealed via an insulating material with a metal lid that also serves as a cathode terminal, the anode is connected to the nickel cylindrical container. 1. A flat primary alkaline battery characterized in that a manganese dioxide mixture is arranged in a concave cross-section over the inner peripheral part and the bottom, and a nickel oxide mixture is arranged in the concave part.