JPS5864759A - Manganese dry cell - Google Patents

Abstract

PURPOSE:To obtain a manganese dry cell excellent in the properties of squeeze processing and corrosion resistance by using high chrome steel, which does not contain Ni but contains a specific quantity of Cr, for a can used for both a collector of a positive pole and a negative pole and collection of electricity. CONSTITUTION:A positive pole 1, which is added by carbon black as a conductive material having MnO2 as the main acting substance as well as molded by pressure while being added by a binder, is inserted into a positive can 2 in a state of directly making contact with the can. Said positive can 2 is formed by high Cr steel, which contains no Ni but not less than 25wt% of Cr. Further a Zn plate 3 of a negative pole is stored directly making contact with a negative can 4, wherein high Cr steel is used like the positive can. Thereby a battery excellent in corrosion resistance can be obtained at a low cost.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a positive electrode active material [Mn01. Znf as negative electrode active material
: This relates to a manganese dry battery using an electrolyte containing ammonium chloride or zinc chloride as a main component, respectively, and relates to improvements in current collectors for the positive electrode and negative electrode for W.

Conventionally, a carbon rod or carbon plate was used for the positive electrode current collector and a carbon plate was used for the negative electrode current collector, but by using high chromium stainless steel with excellent corrosion resistance, a compact high-speed The aim is to obtain high-performance manganese dry batteries.

Conventional manganese dry batteries use carbon rods or carbon plates as the positive electrode current collector, but carbon materials have the drawbacks of poor electrical conductivity and weak mechanical strength. Furthermore, Z as a negative electrode active material
Since Zn was used as both a current collector and a container, when the battery is discharged, Zn decomposes and becomes thinner, creating a hole in the container and leaking liquid. There was a need. Conventionally, only about 30 pieces of Zn were used as an active material, and the rest was wasted, which was a bottleneck in downsizing.

In order to overcome these drawbacks, the present invention uses high chromium stainless steel for the current collector.

In aqueous solutions of halogen salts containing oxidizing compounds, gold generally corrodes and cannot be used as a current collector, but titanium, which is in Group 4 of the periodic table, cannot be used as a current collector.

It is known that zirconium or tantalum of Group 5 is effective as a corrosion-resistant material because a passive film insoluble in an electrolyte is formed on the surface of these metals.

However, zirconium and tantalum are expensive resources as they are rare resources, and titanium, whose demand has been increasing recently, is cheaper than precious metals, but is generally used as a material for battery cans. It is still about 10 times more expensive than 504 material, and has drawbacks such as poor drawing workability.

Satisfied with these price, drawing workability 9 strength, appearance, etc.
In addition, we discovered that steel containing at least 25% by weight of chromium, with almost no nickel, was the best material for secondary battery cans with excellent corrosion resistance.

In addition, the nickel content is J Engineering 8. Since it is specified that the ferrite material of G4312 has α of 60% or less, this was considered to be an amount that is hardly contained.

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

Example Figure 1 is a cross-sectional view of a button-type battery, and in the figure, 1 is M.
This is a positive electrode made of nOmt as the main active material, carbon black as a conductive material, and press-molded with a binder added, and this positive electrode is placed in the positive electrode can 2 in direct contact with the can. . The positive electrode can 2 is made of high chromium steel according to the invention. An example of the composition is shown in Table 1.

Table 1 shows a negative electrode Zn plate, which is housed in direct contact with an electrode can 4 made of high chromium steel like the positive electrode can. 5 is a separator made of cotton coated with etherified starch. The positive electrode can 2 containing each active material is hermetically sealed by attaching its upper part to the electrode can 4 through a nylon gasket 6. Similarly, in order to prevent deformation of the positive electrode during caulking, a pedestal 7 is inserted into the positive electrode. As an electrolyte, 30 to 40% by weight of Zncl!
, an aqueous solution containing ammonium chloride was used.

The battery size was 1t6ms in diameter and 50mm in height.

Example 2 As shown in Figure 2, a cylindrical battery is used, and in the figure, 8 is made of the same material as the positive electrode can 2 described in Example 1 and has a thickness of 0.
．． Expanded metal made of 211B chromium steel plate is used. On top of this, manganese dioxide gold is the main active material, carbon black is added as a conductive agent, and a binder is added and applied, followed by pressing and drying the positive electrode. It is.

9 is a negative electrode of Zn, and both positive and negative electrodes are separator 1
The battery electrode can 11 made of high chromium steel of the present invention also serves as a negative electrode terminal. The sealing metal 12 has a sealing conduction 8×15, which is surrounded by a nylon gasket 14, and further has a sealing conduction portion 1.
3 has a cap 15 that also serves as a positive electrode terminal. This sealing temporary 12 is placed on the groove 16 made in the upper part of the battery electrode can 11, and the upper end 1 of the electrode can 11 is placed on the groove 16.
It is sealed by folding 7 inward.

Reference numeral 18 denotes a lead for electrically connecting the positive electrode and the conductive portion 15. The electrolyte solution is the same as in Example 1.

Next, the effects of the present invention will be described.

FIG. 3 shows a comparison between the button type battery described in Example 1 and a battery using the high chromium steel of the present invention and conventional 5US304 steel as the battery can material.

Figure 5 shows that after storage at 60°C for 40 days, 7.5% at 25°C
In the figure, A and B are according to the present invention, and A is 30% (!r gold content 'B is 20%).
It is monochrome steel containing 5% Or.

Examples of the main components of father B are as follows.

Moreover, they are 0Vi8US430 steel and DijSUS504 steel.

As is clear from the figure, batteries according to the invention (A and B) in which high chromium steel without N1 was used for the battery can after storage.
Almost no performance deterioration was observed. On the other hand, it was found that the other batteries (C and D) had bulging of the battery cans and corrosion in some parts of the cans immediately after storage, and the characteristics had significantly deteriorated. When a similar experiment was conducted using a cylindrical dry battery as shown in Figure 2, it showed the same tendency as the button type battery.

Next, a comparison of leakage resistance was performed, which is shown in Table 5.

Table 3 compares the leakage failure rate after 40 days of storage in an atmosphere of 60° C. and 90% relative humidity. Judgment was made by visual inspection, and if even a small amount of white powder was observed from the gasket, it was judged as defective, regardless of size. The definition of leakage failure rate is as follows.

As is clear from Table 3, the batteries of the present invention (A
and B), and in the other batteries, white powder was protruding from the gap between the negative electrode can and the gasket, and the bottom of the positive electrode can was all bulged. Furthermore, as a result of the disassembly, pitting corrosion occurred on the inside of the bottom of the positive electrode can, and it was evident that the corrosion had progressed due to the battery can material and electrolyte.

When comparing cylindrical dry batteries under the same conditions, the same trends as button batteries were observed.

From the above results, it is recognized that the higher the chromium content, the better the corrosion resistance, and that the corrosion resistance is excellent at VC of 25 weight or more. Furthermore, it was thought that the fact that it did not contain nickel improved its corrosion resistance.

As described above in detail, corrosion resistance can be improved by using high chromium steel that does not contain nickel and contains 25% by weight or more of chromium for the current collectors of the positive and negative electrodes or the cans that also serve as current collectors. Since f'N'fc batteries can be obtained immediately and small manganese dry batteries that are inexpensive and highly practical can be supplied, the industrial value is extremely large.

[Brief explanation of the drawing]

FIGS. 1 and 2 are cross-sectional views of button-type and cylindrical manganese dry batteries, respectively, and FIG. 3 is a comparison diagram of discharge. 1.8...Positive electrode active material 2.15...Positive electrode can 3.9...Negative electrode active material 4.11...Negative electrode can 510...Separator 614...Gasket 7......Positive electrode pedestal 12...Sealing root 13...Sealing conduction part 16...Negative electrode groove 17...Negative electrode upper end part 18...Applicant for positive electrode leads and above Daini Seikosha Co., Ltd. Agent Patent attorney Tsutomu Mogami

Claims (1)

[Claims] (1) Manganese drying using manganese dioxide as the positive electrode active material and zinc as the negative electrode active material, and using an electrolyte containing ammonium chloride or zinc chloride as the main base 1. A manganese dry battery having a q# characteristic in that steel containing almost no nickel and containing 25% by weight or more of chromium is used as a current collector for the positive and negative electrodes.