JP3087536B2 - Manganese dry cell - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a manganese dry battery in which a lead salt is added to the electrolyte of a so-called paper-lined dry battery and mercury and cadmium are not added.

[0002]

2. Description of the Related Art In recent years, mercury, cadmium, and lead contained in batteries have been considered to be environmental problems as a result of environmental pollution. However, dry batteries contain a small amount of mercury, cadmium, and lead. The consumption is so large that it cannot be ignored.

In general, mercury is mainly used in dry batteries as a corrosion inhibitor for a negative electrode zinc can. This mercury is contained in the separator and incorporated into the battery. The separator is obtained by applying a paste consisting of starch and a water-soluble paste material to a separator base paper. The positive electrode mixture is covered with the separator and filled in a negative electrode zinc can. Mercury of about several weight% is added to the above-mentioned paste applied to the separator. When the separator comes into close contact with the inner surface of the zinc can, the surface of the zinc can is amalgamated and corrosion can be effectively suppressed.

In addition, cadmium and lead can be added to the negative electrode zinc can itself to suppress the corrosion of the zinc can (for example, JP-A-61-88451).

[0005]

However, starting from the treatment of waste dry batteries, the mercury in dry batteries has received much attention as an environmental problem, and the mercury that does not use the above-mentioned mercury without impairing the performance of the dry batteries. Although dry batteries have been manufactured, it is now necessary to further eliminate the use of cadmium and lead or to significantly reduce the weight.

[0006]

According to the present invention, in order to achieve cadmium-free manganese dry battery and to further reduce lead, a lead salt containing a specific amount of lead is added to an electrolyte contained in a mixture. In such a case, the intended problem can be solved.

[0007]

By using the above-mentioned means, lead can be replaced with zinc atoms and adhered to the surface of the zinc can, and as a result, lead can be efficiently present at the interface between the zinc can and the separator. Can reduce the amount of lead in zinc cans.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A zinc chloride type manganese dry battery according to an embodiment of the present invention will be described below with reference to the drawings.

In FIG. 1, 1 is a separator, 2 is a negative electrode zinc can, and 3 is a positive electrode mixture containing manganese dioxide as an active material. The positive electrode mixture 3 is wrapped in the separator 1 and filled in the negative electrode zinc can 2, and the positive electrode carbon rod 4 is inserted into the center thereof.
The opening of the zinc can 2 is sealed with a resin gasket 5. A negative electrode terminal plate 6 is applied to the bottom surface of the zinc can 2, and a positive electrode terminal plate 7 is put on a protruding end of the positive carbon rod 4. Then, the outer peripheral surface of the zinc can 2 is covered with the resin tube 8, and the outer can 9 is attached to the outside thereof.

The separator 1 is obtained by applying a paste consisting of starch and a water-soluble paste to kraft paper.

The electrolyte to be added to the positive electrode mixture 3 has a composition of 30 to 50 parts by weight of zinc chloride and 0 to 6 parts by weight of ammonium chloride with respect to 100 parts by weight of water. In particular, in the dry battery according to the embodiment of the present invention, the electrolyte contained in the positive electrode mixture 3 contains 0.0020 as a corrosion inhibitor for the negative electrode zinc can 2.
Lead salt (Pb) so as to contain 0.0075% by weight of lead.
Cl ₂₎ to which was added in a range of 0.0026 to 0.010 wt%. The lead contained in the electrolyte and mixed with the positive electrode mixture 3 in the form of a lead salt penetrates into the inner surface of the negative electrode zinc can 2 through the separator 1 after the battery is assembled, is replaced and acts in the same manner as cadmium. Corrosion of the zinc can 2 is effectively suppressed.

The effect of the present invention was confirmed by a comparative test of the following four types of single type zinc chloride type manganese dry batteries.

Battery A: a manganese dry battery containing no lead salt in the electrolytic solution and containing 0.05% by weight of cadmium and 0.15% by weight of lead in a zinc can used without mercury Battery B: an electrolytic solution A zinc can that contains no lead salt and contains no cadmium and contains 0.15% by weight of lead. A manganese dry battery with no mercury added. Battery C: Electrolyte containing 0.0050% by weight of lead and lead chloride. Using a positive electrode mixture made of manganese, the zinc can used does not contain cadmium and contains 0.15% by weight of lead. A manganese dry battery with no mercury added. Battery D: Lead added with 0.0050% by weight of lead chloride. A manganese dry battery containing no cadmium and reduced to 0.07% by weight of lead using a positive electrode mixture using the electrolyte solution prepared above. Mercury-free manganese dry battery. Negative electrode after storage for 3 months at the same temperature The weight loss of the zinc can was examined. The initial weight of the zinc can used was 22 g. Battery A is 0.18g
Of battery B, 0.32 g of battery B, and 0.19 of battery C
g, the weight of the battery D was 0.19 g.

That is, in the battery D using the electrolytic solution according to the present invention, the same corrosion inhibiting effect as that of the conventional battery A using no mercury is recognized. The effect of the present invention described above becomes remarkable when 0.0020% by weight or more of lead chloride is added to the electrolytic solution. Even if the added amount exceeds 0.0075% by weight, the effect is increased. Hardly connects.

[0015]

As described above in detail, according to the present invention, even if a zinc can of a manganese dry battery which does not use mercury or cadmium and has a total lead content reduced by half is used, corrosion of the zinc can is effectively prevented. A manganese dry battery that can be suppressed to a minimum can be provided.

[Brief description of the drawings]

FIG. 1 is a half sectional view of a manganese dry battery showing a typical configuration of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Separator 2 Negative electrode zinc can 3 Positive electrode mixture 4 Carbon rod 5 Resin gasket 6 Negative terminal board 7 Positive terminal board 8 Resin tube 9 Outer can

Claims (1)

(57) [Claims] 1. A separator coated on the surface with a paste consisting of starch and a water-soluble paste material is placed in intimate contact with the inner surface of a zinc can, into which manganese dioxide and a conductive agent are mixed with an electrolytic solution and mixed and molded. A dry battery filled with the prepared positive electrode mixture, wherein the electrolyte contained in the positive electrode mixture contains 0.0020 to
A manganese dry cell free of mercury and cadmium, wherein a lead salt containing 0.0075% by weight of lead is added.