JP2001229923A - Zinc alloy powder and alkaline storage battery using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a zinc alloy powder for an alkaline storage battery, having superior anticorrosiveness and improved battery discharge characteristics in particular, high-rate discharge characteristics and suiting a negative electrode active material for the alkaline storage battery, and the alkaline storage battery using the zinc alloy powder. SOLUTION: The zinc alloy powder for the alkaline storage battery contains 0.005-0.05% by weight of at least one or more types of a trace of added metal Al, Bi, Ca, In, Mg, Pb, Sn. It is formed by mixing a 5-50% by weight of particulate powder, to which heat treatment is given in an inert gas atmosphere and a 50-95% by weight of untreated zinc alloy powder in the particle size range of 20-150 mesh, 35-150 mesh, 20-200 mesh or 35-200 mesh.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a zinc alloy powder for an alkaline battery which is used as a negative electrode active material as a zinc alloy powder for an alkaline battery and which has excellent corrosion resistance and improved discharge performance. It relates to the alkaline battery used.

[0002]

2. Description of the Related Art Heretofore, zinc alloy powder for alkaline batteries has been produced from a molten zinc alloy by an atomizing method (air atomizing). The zinc alloy powder thus obtained is filled in a battery as a negative electrode of an alkaline battery. The discharge performance is improved by using a zinc alloy powder having a high ratio of fine powder as a negative electrode material, but the amount of hydrogen gas generated is increased. However, problems such as leakage of the electrolyte from the battery are assumed, and the battery has not been put to practical use.

Further, it has been reported in Japanese Patent Laid-Open No. 3-3599 that the heat treatment of a trace metal-added zinc alloy powder, which is a negative electrode active material of an alkaline battery, suppresses the generation of hydrogen gas.
No. 73, JP-A-8-151407 and the like, there is a problem that the internal resistance increases and the discharge characteristics deteriorate.

The present invention relates to a zinc alloy powder for an alkaline battery, which is excellent in corrosion resistance and can improve battery discharge characteristics, particularly high-rate discharge performance, and which is suitable for use as a negative electrode active material of an alkaline battery. It is to provide an alkaline battery used.

[0005]

Means for Solving the Problems In order to solve the above problems, the present inventors examined the amount of hydrogen gas generated and the battery characteristics of the heat-treated trace metal-added zinc alloy powder by particle size. It was confirmed that the effect of suppressing hydrogen gas generation was large and the rate of increase in internal resistance was low. For this reason, as a result of various examinations, only the fine powder having a low internal resistance and excellent discharge performance was subjected to heat treatment, and untreated normal particle size products (20 to 150
mesh or 35-150 mesh or 20-
By mixing with 200 mesh or 35 to 200 mesh), it was confirmed that even if the ratio of fine powder was increased, the amount of hydrogen gas generated could be equal to or reduced from the current product, the internal resistance was suppressed, and the discharge performance was improved, The present invention has been reached.

That is, the invention of claim 1 is directed to an alkaline battery containing at least one of at least one of Al, Bi, Ca, In, Mg, Pb and Sn, which is a trace addition metal, in an amount of 0.005 to 0.05% by weight. 5 to 50% by weight of a zinc alloy powder which has been heat-treated in an inert gas atmosphere and 20 to 150 me
sh or an untreated zinc alloy powder having a particle size range of 35 to 150 mesh, and a zinc alloy powder for an alkaline battery obtained by mixing 50 to 95% by weight.

[0007] The invention of claim 2 is based on claim 1,
Fine powder is 150-300 mesh or 150 mesh
h or less.

[0008] The invention of claim 3 provides a method for manufacturing a semiconductor device comprising:
At least one of Bi, Ca, In, Mg, Pb and Sn
A zinc alloy powder for an alkaline battery containing 0.005 to 0.05% by weight of a seed or more, wherein 5 to 50% by weight of a fine powder heat-treated in an inert gas atmosphere is added to 20 to 200 mesh or 35 to 200 mesh. It is a zinc alloy powder for an alkaline battery obtained by mixing 50 to 95% by weight of an untreated zinc alloy powder having a particle size range.

[0009] The invention of claim 4 is the invention according to claim 3,
Fine powder is 200-300 mesh or 200 mesh
h or less.

The invention of claim 5 is characterized in that the invention is an alkaline battery using the zinc alloy powder of claims 1 to 4 as a negative electrode active material.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail.
The present invention provides a method for adding a trace amount of added metal Al, Bi, Ca, In, M
g, Pb, Sn at least one of 0.005 to
5 to 50% by weight of a zinc alloy powder for an alkaline battery containing 0.05% by weight, which is heat-treated in an inert gas atmosphere.
% By weight and 20 to 150 mesh or 35 to 150
mesh or 20-200 mesh or 35-
Untreated zinc alloy powder 50-9 with a particle size range of 200 mesh
5% by weight of a zinc alloy powder for alkaline batteries.

Here, the untreated zinc alloy powder refers to a zinc alloy powder that has not been heat-treated. Also, trace amounts of added metals Al and B
If at least one of i, Ca, In, Mg, Pb, and Sn is 0.005% by weight or less, the effect of the added metal is not sufficient, and if it is 0.05% by weight or more, the discharge capacity decreases. Further, when the fine powder heat-treated in an inert gas atmosphere is 5% by weight or less, the discharge performance is not sufficiently improved,
If it is 50% by weight or more, the suppression of hydrogen gas generation is not sufficient.

[0013]

EXAMPLES Preferred examples showing the effects of the present invention are shown in Table 1 below, but the present invention is not limited to these examples. 1 to 6 were created based on the numerical values in Table 1.
FIG. 1 is a graph of the pre-discharge gas generation rate of zinc alloy powder for each particle size. The alloy composition was 0.015% by weight of Bi and 0.05% by weight of In and 0.2% of Bi.
025% by weight, 0.025% by weight of In, Ca0.01
Using two samples of which 3% by weight was added, a comparison was made between the case where heat treatment was performed and the case where heat treatment was not performed. The heat treatment was performed by allowing to stand still at 300 ° C. for 2 hours in an argon gas atmosphere and allowing it to cool naturally.

The gas generation rate of the zinc alloy powder before discharge was measured by using 5 ml of a 40% by weight aqueous solution of potassium hydroxide saturated with zinc oxide as an electrolytic solution, and immersing 10 g of the zinc alloy powder in this. The measurement was performed by measuring the gas generation rate (μl / g · day) at 45 ° C. for 3 days. From FIG. 1, it can be seen that the generation of hydrogen gas is suppressed for each particle size by performing the heat treatment, but the effect of the heat treatment is particularly large on the fine powder side.

FIG. 2 shows the results obtained by measuring the internal resistance of the alkaline battery for each particle size of the zinc alloy powder used for the negative electrode. The alloy composition was composed of two samples, one containing 0.015% by weight of Bi and 0.05% by weight of In, and the other containing 0.025% by weight of Bi, 0.025% by weight of In, and 0.013% by weight of Ca. A comparison was made between the case where heat treatment was performed and the case where heat treatment was not performed. The heat treatment was performed by allowing to stand still at 300 ° C. for 2 hours in an argon gas atmosphere and allowing it to cool naturally.

As shown in FIG.
After storage in an IS standard LR6 format at a temperature of 20 ° C. for 7 days, the internal resistance was measured with a battery tester. FIG.
From this, it can be seen that the internal resistance tends to increase for each particle size by performing the heat treatment, but the increase rate of the internal resistance is low on the fine powder side.

FIG. 3 shows the discharge duration of the alkaline battery.
It was measured for each particle size of the zinc alloy powder used for the negative electrode. The alloy composition was 0.015% by weight of Bi and 0.0% of In.
5 wt% added, 0.025 wt% Bi, I
Using two samples in which 0.025% by weight of n was added and 0.013% by weight of Ca, a comparison was made between the case where heat treatment was performed and the case where heat treatment was not performed. The discharge duration is B
The values are shown as relative values with the discharge duration of 100 when using a zinc alloy powder that has not been subjected to a heat treatment of 20 to 200 mesh to which 0.015% by weight of i and 0.05% by weight of In have been added. Heat treatment is performed in an argon gas atmosphere for 30 minutes.
This was carried out by allowing to stand still at 0 ° C. for 2 hours and naturally cooling.

After storing the alkaline battery in JIS standard LR6 format for 7 days at a temperature of 20 ° C., after measuring the internal resistance in FIG. 2, a continuous discharge is performed with a discharge resistance of 1Ω, and the final voltage is reduced to 0.9 V. The duration of the discharge up to that point was measured. From FIG. 3, it can be seen that the duration of the discharge tends to be shorter for each particle size when the heat treatment is performed, but the influence of the heat treatment is smaller on the fine powder side than on the coarse powder side.

According to the results shown in FIGS. 1 to 3, the level of hydrogen gas generation is originally low on the coarse particle side, and conversely, the heat treatment reduces the discharge performance.
It can be seen that heat treatment of the entire zinc alloy powder is not appropriate.

FIG. 4 shows the pre-discharge gas generation rate of the zinc alloy mixed powder measured for each mixing ratio. Alloy composition is Bi
Of 0.015% by weight and 0.05% by weight of In are used.
sh or less, 200-300 mesh, 150-300 m
Four kinds of fine powder of esh were heat-treated. Next, 150m
The heat-treated zinc alloy powder of less than esh and 150-300 mesh is mixed with the untreated zinc alloy powder of 20-150 mesh, and less than 200 mesh and 200-300 mesh
Was mixed with untreated zinc alloy powder of 20 to 200 mesh, and the gas generation rate before discharge of the zinc alloy powder was measured for each mixing ratio. The heat treatment was performed by allowing to stand still at 300 ° C. for 2 hours in an argon gas atmosphere and allowing it to cool naturally.

The gas generation rate of the zinc alloy mixed powder before discharge was measured by using 5 ml of a 40 wt% aqueous solution of potassium hydroxide saturated with zinc oxide as an electrolytic solution.
This was carried out by immersing 10 g of zinc alloy powder in this and measuring the gas generation rate (μl / g · day) at 45 ° C. for 3 days. FIG. 4 shows that when the mixing ratio exceeds 50% by weight, the amount of gas generated increases. Also, 20
The same tendency was observed in the conventional method in which all of a mixture of zinc alloy powder of 200 mesh or less and fine powder of 200 mesh or less was heat-treated.

FIG. 5 shows the internal resistance of the alkaline battery measured for each mixing ratio of the zinc alloy mixed powder used for the negative electrode. The alloy composition was 0.015% by weight of Bi and 0.0% of In.
5% by weight was added, and the particle size range was 200mes.
h or less, 150 mesh or less, 200-300 mes
h, four types of fine powder of 150 to 300 mesh were heat-treated. Next, 150 mesh or less and 150-300m
The heat-treated zinc alloy powder of esh is mixed with untreated zinc alloy powder of 20 to 150 mesh, and 200 mesh or less and 2
The heat-treated zinc alloy powder of 00 to 300 mesh is 20 to 2
The mixture was mixed with 00 mesh untreated zinc alloy powder, and the internal resistance of the zinc alloy powder was measured for each mixing ratio. The heat treatment was performed by allowing to stand still at 300 ° C. for 2 hours in an argon gas atmosphere and allowing it to cool naturally.

The alkaline battery was JIS standard LR6 format, stored at a temperature of 20 ° C. for 7 days, and then the internal resistance was measured with a battery tester. From FIG. 5, it can be seen that the higher the mixing ratio, the lower the internal resistance tends to be. Moreover, 200 me is added to the zinc alloy powder of 20 to 200 mesh powder.
At any mixing ratio, the internal resistance tends to be lower as compared with the conventional method in which all of the powders having a particle size of sh or less are heat-treated. In particular, it can be seen that the internal resistance is remarkably low at a mixing ratio of 30 to 50%.

FIG. 6 shows the discharge duration of the alkaline battery measured for each mixing ratio of the zinc alloy mixed powder used for the negative electrode. The alloy composition used was 0.015% by weight of Bi and 0.05% by weight of In. The particle size range was 200.
less than mesh, less than 150 mesh, 200-300m
Four types of fine powders of esh and 150 to 300 mesh were heat-treated. Next, 150 mesh or less and 150 to 3
00mesh heat treated zinc alloy powder is 20 ~ 150me
sh untreated zinc alloy powder, heat treated zinc alloy powder of 200 mesh or less and 200-300 mesh
The mixture was mixed with 0 to 200 mesh untreated zinc alloy powder, and the duration of discharge of the zinc alloy powder was measured for each mixing ratio. The heat treatment was performed by allowing to stand still at 300 ° C. for 2 hours in an argon gas atmosphere and allowing it to cool naturally.

The alkaline battery was stored in a JIS standard LR6 format at a temperature of 20 ° C. for 7 days, then was continuously discharged with a discharge resistance of 1Ω, and the duration of discharge until reaching a final voltage of 0.9 V was measured. FIG. 6 shows that the discharge time tends to increase as the mixing ratio increases. Also,
200 mesh to zinc alloy powder of 20-200 mesh powder
The discharge time tends to be longer at any mixing ratio as compared with the conventional method in which all of the following fine powders are mixed and heat-treated. In particular, it can be seen that the discharge time is significantly increased at a mixing ratio of 30 to 50%.

According to the results shown in FIGS. 4 to 6, when only the fine powder is subjected to the heat treatment, up to the mixing ratio of 50%,
It can be seen that gas generation before discharge is suppressed to a level equivalent to that of a product in which fine powder is not mixed, and that the discharge time is longer than when heat treatment is applied to all particle sizes.
In particular, when 30 to 50% of the heat-treated fine powder is mixed, a remarkable effect is obtained.

Further, the alloy composition of the zinc alloy powder is set to a Bi content of 0.1.
A test similar to the above was conducted with the addition of 0.05% by weight, 0.05% by weight of In, 0.01% by weight of Mg, and 0.01% by weight of Sn. The results are shown in Example 16 in Table 1. And Comparative Examples 17 to 19. In addition, the alloy composition of the zinc alloy powder is changed to B
The same test was performed by adding 0.05% by weight of i, 0.05% by weight of In, and 0.05% by weight of Al. The results were compared with Examples 12 to 15 in Table 1. Example 12-
The results are shown in FIG. In these cases, the same tendency as that shown in FIGS. 1 to 6 was observed.

Table 1

[0029]

EFFECTS OF THE INVENTION A zinc alloy powder for an alkaline battery suitable for use as a negative electrode active material of an alkaline battery, which is excellent in corrosion resistance and can improve battery discharge characteristics, particularly high-rate discharge performance, and using this zinc alloy powder An alkaline battery can be provided. Further, the fine powder generated in the gas atomization method can be used as a negative electrode material without waste.

[Brief description of the drawings]

FIG. 1 is a graph showing the gas generation rate before discharge for each particle size of zinc alloy powder.

FIG. 2 is a graph showing internal resistance according to zinc alloy powder particle size.

FIG. 3 is a graph showing a discharge duration for each particle size of a zinc alloy powder.

FIG. 4 is a graph showing a pre-discharge gas generation rate depending on a mixing ratio of heat-treated fine powder.

FIG. 5 is a graph showing internal resistance depending on the mixing ratio of heat-treated fine powder.

FIG. 6 is a graph showing a discharge duration according to a mixing ratio of heat-treated fine powder.

FIG. 7 is a cross-sectional view illustrating an alkaline battery used in the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Positive electrode can, 2 ... Positive electrode, 3 ... Separator, 4 ... Negative electrode,
5: negative electrode current collector, 6: sealing cap, 7: gasket,
8 ... negative electrode terminal.

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 5H024 AA03 AA14 BB01 BB07 BB18 CC02 FF31 FF40 HH01 HH13 5H028 BB05 BB06 BB15 EE01 FF02 FF05 HH01 HH05 5H050 AA02 AA18 BA04 CA05 CB13 DA03 FA17 GA02 GA05

Claims (5)

[Claims] 1. A method according to claim 1, wherein the addition of a small amount of metal Al, Bi, Ca, In,
0.005 or more of at least one of Mg, Pb and Sn
5 to 50% by weight of a zinc alloy powder for an alkaline battery which is heat-treated in an inert gas atmosphere.
% By weight and 20 to 150 mesh or 35 to 150
A zinc alloy powder for an alkaline battery, characterized by being mixed with 50 to 95% by weight of an untreated zinc alloy powder having a mesh particle size range. 2. The method according to claim 1, wherein the fine powder is 150 to 3
A zinc alloy powder having a particle size range of 00 mesh or 150 mesh or less. 3. A small amount of added metal Al, Bi, Ca, In,
0.005 or more of at least one of Mg, Pb and Sn
5 to 50% by weight of a zinc alloy powder for an alkaline battery which is heat-treated in an inert gas atmosphere.
% By weight and 20-200 mesh or 35-200
A zinc alloy powder for an alkaline battery, characterized by being mixed with 50 to 95% by weight of an untreated zinc alloy powder having a mesh particle size range. 4. The method according to claim 3, wherein the fine powder is 200 to 30.
A zinc alloy powder having a particle size range of 0 mesh or 200 mesh or less. 5. An alkaline battery comprising the zinc alloy powder according to claim 1 as a negative electrode active material.