JPH0831428A - Negative electrode collector and button alkaline battery using it - Google Patents

Abstract

PURPOSE:To restrict the generation of hydrogen gas, and to restrict the deterioration of the performance of a battery during the storage by coating the surface of a negative electrode collector, which contacts with a gel-type zinc negative electrode, with In or Sn, and coating a part of the negative electrode collector, which contacts with a gasket, with the water repellent agent. CONSTITUTION:The positive electrode mix, which includes MnO2, is housed in a positive electrode case 7, and a separator 3 and the liquid holding material 4 are placed thereon, and a negative electrode collector 1, which also works as a negative electrode case, is fixed thereon through a gasket 5, and this negative electrode collector 1, which also works as a negative electrode case, is filled with the gel-type zinc negative electrode 2 composed of Zn alloy, alkaline electrolyte and the gelatinizer. In a button alkaline battery with the described structure, the negative electrode collector 1 is made of the three-layer clad material, which is formed of Ni-stainless-Cu, and the surface part, which contacts with the gel-type zinc negative electrode 2, is coated with In or Sn by electroless plating, and furthermore, a part of the negative electrode collector 1, which contacts with the gasket 5, is coated with the water repellent agent, and dried at a low temperature, for example, at 90 deg.C or less.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a negative electrode current collector that also serves as a negative electrode case of a button type alkaline battery, and more specifically, a button type without mercury addition capable of suppressing generation of hydrogen gas and preventing performance deterioration during storage. Regarding alkaline batteries.

[0002]

2. Description of the Related Art Button-type alkaline batteries having zinc as a negative electrode include various batteries having manganese dioxide, silver oxide, or oxygen in the air as a positive electrode acting substance according to the application. These batteries are used for watches and hearing aids. , The demand is expanding to small electronic devices.

Conventionally, mercury is added to the gelled zinc negative electrode in alkaline batteries having zinc powder as the negative electrode, not limited to the button type. This mercury covered the surfaces of the zinc alloy powder and the negative electrode current collector, increased their hydrogen overvoltage, and suppressed the generation of hydrogen gas.

However, in recent years, with increasing interest in the living environment, it has become a problem that a small amount of harmful mercury is contained in the battery, and the development of a battery without addition of mercury has become a problem. Was wanted.

However, unless mercury is added to the battery,
Generation of hydrogen gas from the zinc alloy powder and the negative electrode current collector increases, which causes problems such as battery swelling, liquid leakage, and drastic performance deterioration during storage. In order to solve these problems, a zinc alloy powder containing indium, bismuth, lead, etc., which is hard to corrode, is used, or an indium compound, a bismuth compound, etc. are contained in the gel zinc negative electrode as a corrosion inhibitor. ing. It has also been proposed to add a surfactant that suppresses corrosion of zinc alloy powder to the gelled zinc negative electrode.
These technologies have already been used in cylindrical alkaline dry batteries, and batteries containing no added mercury have been put on the market.

[0006]

On the other hand, in the button type alkaline battery, even if the same technique as that of the cylindrical alkaline dry battery is applied as it is, it is not sufficient to suppress the generation of hydrogen gas and the swelling of the battery and the Problems such as liquid leakage will occur.
This is because the cylindrical alkaline dry battery has a space for receiving the generated hydrogen gas to some extent, but the button alkaline battery does not have such a space and almost no generation of hydrogen gas inside the battery is allowed. Therefore, in the button type alkaline battery, it is necessary to suppress the generation of hydrogen gas more than in the cylindrical alkaline dry battery.

By the way, when the content of the indium compound or the surfactant is increased, the effect of suppressing the hydrogen gas is increased, but the battery performance is affected. Particularly, when a large amount of the surfactant is added, the battery performance is improved. It becomes a factor that significantly deteriorates the electrical characteristics and the discharge performance.

To make matters worse, even if the generation of hydrogen gas from the zinc alloy powder can be suppressed by these techniques, the generation of hydrogen gas from the negative electrode current collector cannot be expected so much. In button-type alkaline batteries, gas generation from the negative electrode current collector is also a big problem, and it is also essential to suppress it.

Therefore, the surface portion of the negative electrode current collector that comes into contact with the gelled zinc negative electrode is coated with a metal having a higher hydrogen overvoltage than zinc, such as indium or tin, to prevent generation of hydrogen gas from the negative electrode current collector. It has been proposed to suppress. However, when the negative electrode current collector is coated with indium, the alkaline electrolyte solution easily crawls up, so that the alkaline electrolyte solution easily leaks from between the gasket and the negative electrode current collector. Although tin does not creep up more than alkaline electrolyte than indium, when electroplating or electroless plating is used as a method for coating the negative electrode current collector, the alkaline electrolyte tends to creep up easily depending on the surface condition. However, there is a problem that the alkaline electrolyte is likely to leak from between the gasket and the negative electrode current collector.

Further, as a method of coating indium or tin, there are electroplating, hot dipping, electroless plating and the like. However, in hot dipping, it is difficult to control the thickness of the indium coating thinly. It becomes electroless plating. In the case of electroplating, it is necessary to mask the non-plated portion and the masking of the negative electrode current collector after the molding process becomes complicated. Therefore, the method of molding the material previously coated with indium or tin is easy. But,
The plated surface may be scratched during the molding process, and foreign matter may easily adhere to it, which may cause generation of hydrogen gas.
On the other hand, electroless plating is advantageous because it can be selectively plated on the copper surface of the negative electrode current collector after molding to cover scratches and foreign matter, and there is little possibility that foreign matter will adhere after plating. Since it is difficult to thicken the plating, the effect of suppressing the generation of hydrogen gas may be smaller than that of electroplating.

The present invention has been made to solve the above problems, and its object is to provide a negative electrode current collector which also serves as a negative electrode case of a button type alkaline battery, and which is used in a button type alkaline battery containing no added mercury. Another object of the present invention is to provide a high-performance button-type alkaline battery having a negative electrode current collector capable of suppressing generation of hydrogen gas and preventing performance deterioration during storage.

[0012]

To achieve the above object, the first aspect of the present invention provides a negative electrode for a button type alkaline battery having a gelled zinc negative electrode composed of a zinc alloy, an alkaline electrolyte and a gelling agent. A negative electrode current collector that also serves as a case, characterized in that indium or tin is present at least on the surface portion in contact with the gelled zinc negative electrode, and a water repellent agent is applied to at least the contact portion with the gasket. .

According to a second aspect of the present invention, the negative electrode current collector also serving as the negative electrode case is composed of a three-layer clad material of nickel-stainless-copper or nickel-iron-copper, and indium is added to the copper surface. Alternatively, the method is characterized in that after coating tin with electroless plating, a water repellent treatment agent is applied, and drying in the water repellent treatment agent applying step and the washing step is performed at 90 ° C. or lower.

A button type alkaline battery according to claim 3 of the present invention uses the negative electrode current collector for a button type alkaline battery according to claim 1 or 2, and uses zinc alloy powder in the gel zinc negative electrode. 0.01 to 0.1 wt% as indium
The indium compound and the surfactant which is stable in an alkaline electrolyte are contained in an amount of 0.01 wt% or less.

[0015]

The mechanism of operation of the button type alkaline battery provided with the negative electrode current collector of the present invention is not necessarily clear, but it is presumed as follows. The indium or tin coated on the surface portion of the negative electrode current collector that is in contact with the gelled zinc negative electrode increases the hydrogen overvoltage of the negative electrode current collector and suppresses the generation of hydrogen gas. Indium and tin easily diffuse into copper, and the higher the temperature, the stronger the tendency.Therefore, if drying is performed at high temperature in the washing process and water repellent treatment process, indium and tin diffuse into the copper. As a result, the effect of suppressing the generation of hydrogen gas becomes small. Therefore, if the drying temperature is suppressed, the diffusion of indium and tin can be prevented. This is particularly effective in electroless plating in which plating cannot be made thick, and the effect of suppressing hydrogen gas generation is maintained if the drying temperature is 90 ° C. or lower.

The water repellent agent applied to the negative electrode current collector prevents the alkaline electrolyte from entering between the gasket and the negative electrode current collector, and prevents the liquid from leaking. Therefore, the effect is exhibited if it is applied to at least the contact portion between the gasket and the negative electrode current collector.

On the other hand, the indium compound contained in the gelled zinc negative electrode and the surfactant stable in the alkaline electrolyte suppress generation of hydrogen gas due to corrosion of the zinc alloy powder. In the gel zinc negative electrode, the indium compound gradually dissolves in the electrolytic solution to form indium ions, which are then deposited on the surface as indium by touching the zinc alloy powder, increasing the hydrogen overvoltage of the zinc alloy powder and making it less likely to corrode. To do. The surface-active agent covers the surface of the zinc alloy powder and limits the contact with the electrolytic solution to prevent corrosion.

In the button type alkaline battery, the effect of suppressing the gas generation is insufficient if only one of the indium compound and the surfactant is contained, and a larger effect can be obtained by containing an appropriate amount of both. can get. The content of the indium compound is limited to 0.01 to 0.1 wt% as indium with respect to the zinc alloy powder, and 0.01 wt%
%, The effect of suppressing gas generation is not exhibited and
If it is more than 1 wt%, the battery performance is greatly affected and the discharge performance and the like deteriorate. Further, the content of the surfactant is limited to 0.01 wt% or less with respect to the zinc alloy powder, and 0.01 w
If the content is more than t%, a large amount adheres to the surface of the zinc alloy powder, which not only has a great adverse effect on electrical characteristics and discharge performance, but also inhibits the hydrogen gas suppressing mechanism of the indium compound, and the effect is not sufficiently exerted. On the contrary, hydrogen gas generation will increase. In addition, the indium compound in the gelled zinc negative electrode also functions to improve the contact between zinc alloy powders and the like and reduce the internal resistance of the battery. This compensates for the adverse effect on the discharge performance that occurs not a little due to the addition of the surfactant, and further improves the performance.

[0019]

EXAMPLES Examples of the present invention will be specifically described below. (Example 1) A three-layer clad material of nickel-stainless-copper was molded into a negative electrode current collector which also served as a negative electrode case used in an LR44 type alkaline manganese battery as shown in FIG. The copper surface of this negative electrode current collector was coated with indium by electroless plating, and then the entire surface was coated with a silicon water repellent agent. Drying in the washing step and the water repellent treatment agent applying step was performed at 80 ° C.

On the other hand, zinc alloy powder containing aluminum, indium and bismuth, 35 wt% potassium hydroxide aqueous solution, polyacrylic acid, zinc alloy powder 0.01 wt% indium oxide as indium oxide and zinc alloy powder A gel type zinc negative electrode was prepared by stirring and mixing 0.003 wt% perfluoroalkyl polyoxyethylene-based surfactant. In addition, electrolytic manganese dioxide and scaly black smoke were stirred and mixed, and then molded to prepare a positive electrode mixture.

An LR44 type alkaline manganese battery as shown in FIG. 1 was prepared using the above negative electrode current collector, gelled zinc negative electrode and positive electrode mixture. In FIG. 1, reference numeral 1 denotes a negative electrode current collector that also serves as a negative electrode case, a gelled zinc negative electrode 2 is present inside the negative electrode current collector 1, and a positive electrode mixture 6 is provided via a liquid holding material 4 and a separator 3. Are arranged. A gasket 5 is arranged so as to enclose the zinc negative electrode 2, the liquid holding material 4, the separator 3 and the positive electrode mixture 6, and a gasket 5 is arranged between the zinc negative electrode 2 and the positive electrode case 7 to be liquid-tightly attached. FIG. 2 shows A of FIG.
FIG. 6 is an enlarged view of a portion, in which a copper surface of a nickel-stainless-copper three-layer clad material is coated with indium or tin.

(Example 2) An LR44 type alkaline manganese battery was produced in the same manner as in Example 1 except that the content of indium oxide was 0.05 wt% as indium based on the zinc alloy powder.

(Example 3) An LR44 type alkaline manganese battery was produced in the same manner as in Example 1 except that the content of indium oxide was 0.1 wt% as indium with respect to the zinc alloy powder.

Example 4 An LR44 type alkali was prepared in the same manner as in Example 2 except that the content of the perfluoroalkylpolyoxyethylene-based surfactant was 0.001 wt% based on the zinc alloy powder. A manganese battery was produced.

Example 5 An LR44 type alkali was prepared in the same manner as in Example 2 except that the content of the perfluoroalkylpolyoxyethylene-based surfactant was 0.005 wt% based on the zinc alloy powder. A manganese battery was produced.

Example 6 An LR44 type alkali was prepared in the same manner as in Example 2 except that the content of the perfluoroalkylpolyoxyethylene-based surfactant was 0.01 wt% with respect to the zinc alloy powder. A manganese battery was produced.

Example 7 LR44 was carried out in the same manner as in Example 1 except that the negative electrode current collector was coated with tin by electroless plating.
Type alkaline manganese battery was prepared.

(Example 8) LR44 was carried out in the same manner as in Example 3 except that the negative electrode current collector was coated with tin by electroless plating.
Type alkaline manganese battery was prepared.

Example 9 LR44 was carried out in the same manner as in Example 2 except that the negative electrode current collector was coated with tin by electroless plating.
Type alkaline manganese battery was prepared.

Example 10 LR4 was carried out in the same manner as in Example 6 except that the negative electrode current collector was coated with tin by electroless plating.
A 4-type alkaline manganese battery was produced. Next, various comparative examples for comparison with the above-described examples of the present invention were prepared as follows.

Comparative Example 1 An LR44 type alkaline manganese battery was produced in the same manner as in Example 1 except that the content of indium oxide was 0.005 wt% as indium based on the zinc alloy powder.

Comparative Example 2 An LR44 type alkaline manganese battery was prepared in the same manner as in Example 1 except that the content of indium oxide was 0.2 wt% as indium based on the zinc alloy powder.

(Comparative Example 3) The content of the perfluoroalkylpolyoxyethylene-based surfactant was 0.015w.
An LR44 type alkaline manganese battery was produced in the same manner as in Example 2 except that the amount was t%.

Comparative Example 4 An LR44 type alkaline manganese battery was prepared in the same manner as in Example 3 except that the gelled zinc negative electrode did not contain a surfactant.

Comparative Example 5 An LR44 type alkaline manganese battery was produced in the same manner as in Example 5, except that the gelled zinc negative electrode did not contain an indium compound.

Comparative Example 6 L was prepared in the same manner as in Example 2 except that a nickel-stainless-copper three-layer clad material was molded into a negative electrode current collector and used as it was without any coating.
An R44 type alkaline manganese battery was produced.

(Comparative Example 7) The content of indium oxide was 0.1 wt% as indium based on the zinc alloy powder, and the content of perfluoroalkyl polyoxyethylene-based surfactant was 0.1% based on the zinc alloy powder. An LR44 type alkaline manganese battery was produced in the same manner as in Comparative Example 6 except that the content was 01 wt%.

(Comparative Example 8) An LR44 type alkaline manganese battery was prepared in the same manner as in Example 1 except that the indium compound and the perfluoroalkylpolyoxyethylene-based surfactant were not contained in the gelled zinc negative electrode. .

Comparative Example 9 L was prepared in the same manner as in Comparative Example 8 except that a nickel-stainless-copper three-layer clad material was molded into a negative electrode current collector and used as it was without any coating.
An R44 type alkaline manganese battery was produced.

(Comparative Example 10) Drying temperature in a washing step and a water repellent treatment agent coating step when indium is coated on a negative electrode current collector formed by molding a nickel-stainless-copper three-layer clad material by electroless plating. An LR44 type alkaline manganese battery was produced in the same manner as in Example 2 except that the temperature was set to 120 ° C.

(Comparative Example 11) Drying temperature in a washing step and a water repellent treatment agent applying step when indium is coated on a negative electrode current collector formed of a nickel-stainless-copper three-layer clad material by electroless plating. A LR44 type alkaline manganese battery was produced in the same manner as in Example 2 except that the temperature was set to 150 ° C.

(Comparative Example 12) Drying temperature in a washing step and a water repellent treatment agent applying step when a negative electrode current collector formed by molding a nickel-stainless-copper three-layer clad material is coated with tin by electroless plating. An LR44 type alkaline manganese battery was produced in the same manner as in Example 9 except that the temperature was set to 120 ° C.

(Comparative Example 13) Drying temperature in a washing step and a water repellent treatment agent coating step when a negative electrode current collector formed by molding a nickel-stainless-copper three-layer clad material is coated with tin by electroless plating. A LR44 type alkaline manganese battery was produced in the same manner as in Example 9 except that the temperature was set to 150 ° C.

(Comparative Example 14) A comparative example was carried out except that a negative electrode current collector formed by molding a nickel-stainless-copper three-layer clad material was coated with tin by electroless plating and then no water repellent agent was applied. An LR44 type alkaline manganese battery was produced in the same manner as in Example 9.

(Comparative Example 15) A comparative example was carried out except that a negative electrode current collector formed by molding a nickel-stainless-copper three-layer clad material was coated with indium by electroless plating and then no water repellent treatment was applied. An LR44 type alkaline manganese battery was produced in the same manner as in Example 2.

(Comparative Example 16) The procedure of Example 2 was repeated, except that the negative electrode current collector formed by molding the nickel-stainless-copper three-layer clad material was coated with the water repellent agent without any coating. Thus, an LR44 type alkaline manganese battery was produced.

(Comparative Example 17) A zinc alloy powder contains lead,
An LR44 type alkaline manganese battery was produced in the same manner as in Comparative Example 9 except that the LR44 type was changed to 3%. Using each prototype battery of the example and the comparative example produced as described above,
Various evaluation tests were conducted. In these various evaluation tests, the leak resistance test is an average value of 50 and the other tests are average values of 20.

Hereinafter, various evaluation test methods and their results will be described. First, the total battery height, open circuit voltage, and internal resistance of the prototype batteries of Examples 1 to 10, Comparative Examples 1 to 9, and Comparative Example 17 were measured. In addition, the discharge duration of 1.3 kΩ continuous discharge up to 1.2 V was measured to investigate the discharge performance of each example. Furthermore, after being stored at 60 ° C. for 40 days, the change in the total height of the battery and the deterioration of the open circuit voltage were measured, and 1.3 kΩ continuous discharge was performed to investigate the deterioration of the discharge performance. The amount of change due to storage at 60 ° C. correlates with the amount of hydrogen gas generated inside the battery, and the smaller the amount of change, the smaller the amount of hydrogen gas generated. Table 1 shows the results.

[0049]

[Table 1]

As is clear from Table 1, Examples 1-3,
According to Nos. 7 and 8 and Comparative Examples 1 and 2, the content of the indium compound in the gelled zinc negative electrode is appropriate to be 0.01 to 0.1 wt%, and when deviating from this range, the generation of hydrogen gas is suppressed. Is insufficient, or the discharge performance is adversely affected.

Further, according to Examples 4 to 6, 9 and 10 and Comparative Example 3, it is appropriate that the content of the surfactant stable in the alkaline electrolyte in the gelled zinc negative electrode is 0.01 wt% or less. If it is out of this range, the discharge performance is significantly deteriorated.

Further, according to Comparative Examples 4 to 9, inclusion of an indium compound in the gel zinc negative electrode, inclusion of a surfactant in the gel zinc negative electrode, and contact with the gel zinc negative electrode of the negative electrode current collector. When any of the coating of indium or tin on the portion to be damaged is lacking, the object of the present invention is not achieved, the suppression of hydrogen gas generation is insufficient, the total battery height is increased, and the discharge performance is significantly deteriorated. Wake up.

Second, Examples 2 and 9 and Comparative Examples 10 to 13
And the same test as described above was performed using each prototype battery of Comparative Example 17, and the influence of the drying temperature on the hydrogen gas generation amount in the washing process of the negative electrode current collector and the water repellent treatment agent applying process was examined. Is shown in Table 2.

[0054]

[Table 2]

According to Table 2, Comparative Examples 10 to 13 in which the drying temperature is higher than 90 ° C. are obviously due to storage, compared with the Examples in which the drying temperature in the washing process and the water repellent treatment agent applying process is 80 ° C. Performance deterioration is progressing, and the higher the drying temperature, the stronger the tendency.

Third, Examples 2 and 9 and Comparative Examples 14 to 16
Each prototype battery of Comparative Example 17 was stored at 60 ° C.-93% RH, and a leak resistance test under high temperature and high humidity was conducted to examine the effect of applying the water repellent treatment agent to the negative electrode current collector. If the amount of hydrogen gas generated inside the battery is large, the resistance to liquid leakage will be poor, but if the electrolyte easily crawls over the negative electrode current collector, even if the amount of hydrogen gas generated is small, leakage will occur from between the gasket and the negative electrode current collector. To liquidate. The results are shown in Table 3.

[0057]

[Table 3]

From Table 3, it can be seen that the battery using the negative electrode current collector of the present invention is obviously excellent in liquid leakage resistance, and the application of the water repellent treatment improves liquid leakage resistance.

The present invention is not limited to the above embodiment. That is, although indium oxide is used as the indium compound and a perfluoroalkylpolyoxyethylene-based surfactant is used as the surfactant in the above-mentioned examples, the indium compound and the surfactant are not limited to these, and other indium compounds and surfactants are used. The effect of the present invention can be obtained even with a combination of indium hydroxide and a polyoxyethylene-based surfactant.

The same applies to the water repellent agent, and a fluorine-based agent may be used. Further, the application method may be any application method as long as the water repellent agent is applied to the portion where the negative electrode current collector contacts the gasket. Other elements such as zinc alloy powder may be changed without departing from the scope of the present invention.

Although the button type alkaline manganese battery has been described in the above embodiment, the present invention is not limited to this, and various button type alkaline batteries such as silver oxide batteries and zinc air batteries having gel zinc as a negative electrode are used. Of course, it can be applied to.

[0062]

As described above, the negative electrode current collector for a button type alkaline battery manufactured according to the present invention produces hydrogen gas from the negative electrode current collector even when used in a button type alkaline battery to which mercury is not added. In addition, the button-type alkaline battery of the present invention containing the appropriate amount of an indium compound and a surfactant that is stable in an alkaline electrolyte in a gel zinc negative electrode can prevent leakage of liquid during storage. It also has the excellent effect of preventing swelling of batteries, deterioration of performance, and the like.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of an LR44 type alkaline manganese battery manufactured in an example of the present invention.

FIG. 2 is an enlarged view of part A in FIG.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Negative electrode collector, 2 ... Gel zinc negative electrode, 3 ... Separator, 4 ... Liquid holding material, 5 ... Gasket, 6 ... Positive electrode mixture, 7
… Positive electrode case.

Claims (3)

[Claims] 1. A negative electrode current collector which also serves as a negative electrode case of a button type alkaline battery having a gelled zinc negative electrode composed of a zinc alloy, an alkaline electrolyte and a gelling agent, and which is in contact with at least the gelled zinc negative electrode. A negative electrode current collector for a button type alkaline battery, characterized in that indium or tin is present on the surface portion thereof, and a water repellent treatment agent is applied to at least a portion contacting the gasket. 2. The negative electrode current collector also serving as the negative electrode case,
It is composed of a three-layer clad material of nickel-stainless-copper or nickel-iron-copper. The copper surface is coated with indium or tin by electroless plating, and then a water repellent treatment agent is applied to the water repellent treatment agent. 90 ° C for drying in coating process and cleaning process
The negative electrode current collector for a button type alkaline battery according to claim 1, which is performed as follows. 3. The negative electrode current collector for a button type alkaline battery according to claim 1 or 2, wherein 0.01 to 0.01 as indium is added to the zinc alloy powder in the gel zinc negative electrode.
A button type alkaline battery containing 0.1 wt% of an indium compound and 0.01 wt% or less of a surfactant stable in an alkaline electrolyte.