JP2000082446A - Alkaline battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To increase the capacity of the alkaline battery and prevent the lowering of a heavy loading characteristic, after storage. SOLUTION: A can obtained by forming a nickel-phosphor plated layer 11 on one side of a cold rolled steel plate 9 previously provided with nickel plated layers 10 on both sides and by pressing, drawing and ironing it such that the side of the nickel-phosphor plated layer 11 becomes the inside surface is used as a positive electrode can of this alkaline battery. Alternatively, the cold rolled steel plate previously provided with the nickel-phosphor plated layers on both sides is prosttrated to form nickel-phosphor alloy plated layers between the steel plate and the nickel-phosphor plated layers, then it is pressed, drawn and ironed to form the can to be used. As necessary, a conductive coating including graphite powder as a primary ingredient is formed further. The use of the positive electrode can such as this prevents increase of internal resistance despite lessening of the content of the graphite powder in the positive electrode mixture for increasing the capacity, and prevents the lowering of a heavy loading characteristic, after storage.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an alkaline battery which has improved performance and is suitable for heavy load applications.

[0002]

2. Description of the Related Art Notebook personal computers, CD players, MDs
2. Description of the Related Art Recently, alkaline dry batteries have been required to be used for ultra-heavy loads or heavy loads such as portable AV equipment such as players, liquid crystal televisions, and mobile phones.

[0003] In such an alkaline dry battery, the positive electrode can is press-drawn and ironed on a steel plate having nickel plating on both surfaces in advance, or nickel-plated after drawing only on the steel plate, and graphite powder is coated on the inner surface of each. A conductive film having a conductive film as a main component is used, whereby the contact resistance between the positive electrode mixture and the positive electrode can is reduced, and the heavy load characteristics are improved.

[0004]

However, in order to increase the capacity of an alkaline dry battery, the content of manganese dioxide in the positive electrode mixture must be increased. The rate is lower. This increases the contact resistance between the positive electrode mixture and the positive electrode can, causing a reduction in short-circuit current and a reduction in heavy load characteristics.

[0005] As a countermeasure, a conductive film is formed on the inner surface of the positive electrode can as described above.
Such a high capacity battery has a problem in that the heavy load characteristics deteriorate after storage, particularly after high temperature storage. The present invention has been made in view of the above problems, and has as its object to achieve an increase in capacity of an alkaline dry battery and to prevent a decrease in heavy load characteristics after storage.

[0006]

SUMMARY OF THE INVENTION The present invention has been achieved by improving the cathode can. That is, the present invention provides (1) a bottomed cylindrical positive electrode can also serving as a positive electrode terminal, a hollow cylindrical positive electrode mixture disposed in the positive electrode can, and the positive electrode mixture via a bottomed cylindrical separator. In the alkaline dry battery comprising a gelled zinc negative electrode filled in the hollow portion, a nickel-phosphorus plating layer is formed on one surface of a cold-rolled steel sheet material on which nickel plating layers are previously formed on both surfaces as the positive electrode can. And a press-drawing and ironing can used so that the surface becomes an inner surface.

Further, according to the present invention, (2) instead of forming a nickel plating layer on both surfaces in advance in the above (1), a nickel-phosphorus plating layer is formed on both surfaces in advance, and the cold-rolled steel material is post-processed. A nickel-phosphorus alloy plating layer is further formed between the steel material and the nickel-phosphorus plating layer, and this is press-drawn and ironed to use a can.

In the positive electrode can used in the alkaline dry battery of the present invention described in (1) and (2), the nickel-phosphorus plating layer formed on the inner surface thereof has an uneven surface due to extremely fine cracks generated during press drawing and ironing. , The contact area with the positive electrode mixture or the conductive film is increased, and the internal resistance of the battery is reduced. On the other hand, a nickel plating layer is formed below the nickel-phosphorous alloy plating layer in the case of (1), and a nickel-phosphorus alloy plating layer is formed in the case of (2). Even if cracks occur, the iron base is less exposed. Therefore, the contact resistance with the positive electrode mixture and the conductive film does not increase due to the oxidation of iron during high-temperature storage, and deterioration of heavy load characteristics after high-temperature storage is small. In the case of (2), the nickel-phosphorous alloy plating layer formed by the post-treatment binds the upper nickel-phosphorous plating layer more firmly than in the case of (1), and the deterioration of the discharge capacity is further reduced.

[0009] Since the alkaline dry battery of the present invention has such characteristics, the amount of manganese dioxide in the positive electrode mixture is increased, and as a result, even if the graphite powder content is 8 wt% or less, the conventional problem arises. Does not occur, so that high capacity can be achieved.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the embodiment of the present invention (1) will be described in detail. Example 1 First, a nickel-phosphorus plating layer having a thickness of 2 μm was further formed on one surface of a cold-rolled steel sheet material having a nickel plating layer having a thickness of 2 μm formed on both surfaces in advance. The nickel-phosphorus alloy plating layer is formed by nickel sulfate 2
0 g / l, sodium hypophosphite 10 g / l, lactic acid 25
g / l and 3 g / l of propionic acid, pH4.
5. Performed by an electroless nickel-phosphorus plating method in which a treatment is performed in a bath at a bath temperature of 85 ° C. The plating film is a nickel-phosphorus alloy containing 3% of phosphorus.

Using this steel sheet, a positive electrode can was formed by press-drawing and ironing into a cylindrical shape with a bottom so that the nickel-phosphorus alloy plating layer surface was on the inside. FIG. 2 shows the configuration of the plating layer of the positive electrode can. As shown in this figure, a nickel plating layer 10 having a thickness of 2 μm is formed on a steel plate 9 of the positive electrode can, and a nickel-phosphorus alloy plating layer 11 having a thickness of 2 μm is formed on a surface inside the can. Have been.

A conductive coating mainly composed of graphite powder was formed on the inner surface of the thus-formed positive electrode can except for the portion of the opening that was in contact with the gasket. The method of applying the conductive coating is performed by diluting a conductive paint containing graphite powder as a main component with a low-boiling organic solvent such as methyl ethyl ketone, and applying it to the inner surface of the positive electrode can in a mist by a spray gun.
Do not apply to the portion of the opening of the positive electrode can that contacts the gasket. After applying the conductive paint with a spray gun,
The solvent is evaporated in a dryer. The thickness of the remaining conductive film is 1
It is preferably about 10 to 10 μm. FIG. 3 shows the configuration of the plating layer of this positive electrode can. In FIG. 3, reference numeral 12 denotes a conductive film.

Using the positive electrode can having the conductive coating shown in FIG. 3, an LR6 (AA) alkaline dry battery shown in FIG. 1 was assembled. In FIG. 1, reference numeral 1 denotes a bottomed cylindrical positive electrode can also serving as a positive electrode terminal manufactured by the above-described method, and a nickel plating layer having a thickness of 2 μm is formed on the inner surface side of the positive electrode can as described above. A nickel-phosphorus alloy plating layer having a thickness of 2 μm is formed thereon, and a conductive film is further formed thereon.

In the positive electrode can, a cylindrical pressure-molded 3
The positive electrode mixture 2 is separately filled. The positive electrode mixture 2 is a mixture of manganese dioxide powder and graphite powder, which is formed into a hollow cylindrical shape at a predetermined pressure using a molding die. The positive electrode mixture is used to increase the discharge capacity. The graphite powder content in the sample No. 2 was 8 wt%.

A hollow cylindrical separator 3 made of a non-woven fabric of acetalized polyvinyl alcohol fiber is disposed in the hollow portion of the positive electrode mixture 2. This separator 3
, A gelled zinc negative electrode 4 made of a non-melonized zinc alloy powder, an alkaline electrolyte and polyacrylic acid as a gelling agent is filled. In the gelled zinc negative electrode 4, a negative electrode current collector rod 5 made of brass is mounted so that its tip is inserted into the gelled negative electrode 4. An insulating gasket 6 made of a double-ringed polyamide resin is disposed on the outer periphery of the upper part of the negative electrode current collector rod 5 and the inner periphery of the upper part of the positive electrode can 1. A ring-shaped metal plate 7 is disposed between the double annular portions of the insulating gasket 6, and a cap-shaped metal sealing plate 8 serving also as a negative electrode terminal is provided on the head of the current collecting rod 5. It is arranged to abut. The opening edge of the positive electrode can 1 is bent inward to seal the inside of the positive electrode can 1 with the gasket 6 and the metal sealing plate 8.

(Example 2) A positive electrode can manufactured in the same manner as in Example 1 was used in the same manner as in Example 1 except that a conductive coating mainly composed of graphite powder was not formed on the inner surface thereof. To assemble a JIS standard LR6 type AA alkaline battery.

(Comparative Example 1) A cold-rolled steel sheet having a 2-μm-thick nickel plating layer formed on both sides in advance is press-drawn and ironed into a bottomed cylindrical shape, and the inner surface mainly contains graphite powder. The one having the conductive film formed thereon was used as a positive electrode can, and the other conditions were the same as in Example 1 in accordance with JIS standard LR6.
(AAA) alkaline batteries were assembled.

(Comparative Example 2) A cold-rolled steel sheet was press-drawn and ironed into a bottomed cylindrical shape, and then a nickel-plated layer having a thickness of 1 to 2 µm was formed. JIS standard LR6 was used in the same manner as in Example 1 except that the conductive can was used as the positive electrode can.
(AAA) alkaline batteries were assembled.

(Comparative Example 3) A JIS standard LR6 (AA) alkaline dry battery was assembled in the same manner as in Comparative Example 1 except that a conductive film mainly composed of graphite powder was not formed on the inner surface. .

(Comparative Example 4) A JIS standard LR6 type (AA) alkaline dry battery was assembled in the same manner as in Comparative Example 2 except that a conductive film mainly composed of graphite powder was not formed on the inner surface. .

Examples 1 to 5 assembled as described above
2. About each LR6 type alkaline dry battery of Comparative Examples 1-4, after storing at 60 degreeC for 0 days, 10 days, and 60 days,
The internal resistance and discharge capacity at 20 ° C. were examined, and the results are shown in Table 1. The internal resistance (mΩ) of each battery 10
The samples were measured using a 1 kHz AC resistance meter, and their average values were shown. As for the discharge capacity, a 2Ω continuous discharge test was performed on each of 10 batteries, and the average value of the duration (min) up to a final voltage of 0.9 V was shown.

[0022]

[Table 1]

As is clear from the above table, Examples 1 and 2
It can be seen that, compared to Comparative Examples 1 to 4, even when the battery was stored at 60 ° C. for 60 days, the internal resistance of the battery did not increase much and the discharge capacity did not deteriorate much.

Next, the embodiment (2) of the present invention will be described. Example 3 First, a hoop material of a cold-rolled steel sheet having a nickel-phosphorus plating layer having a thickness of 2 to 3 μm formed on both surfaces in advance is heated at a temperature of 500 to 600 ° C. for several hours, and the steel sheet and the nickel-phosphorus plating are applied. A nickel-phosphorus alloy plating layer was formed between the layers. The nickel-phosphorus plating layer was formed in the same manner as in Example 1.

Using this steel sheet, a positive electrode can was formed by press-drawing and ironing into a bottomed cylindrical shape. FIG. 4 shows the configuration of the plating layer of this positive electrode can. As shown in this figure,
A nickel-phosphorus plating layer 11 having a thickness of 2 to 3 μm is formed on the steel plate 9 of the positive electrode can, and a nickel-phosphorus alloy plating layer 13 is formed between the nickel-phosphorus plating layer 11 and the steel plate 9.

A conductive coating mainly composed of graphite powder was formed on the inner surface of the thus-formed positive electrode can except for the portion in contact with the gasket in the opening. The method of applying the conductive film is the same as that in Example 1 described above. The conductive paint containing graphite powder as a main component is diluted with a low boiling organic solvent such as methyl ethyl ketone and applied to the inner surface of the positive electrode can in a mist by a spray gun. And do not apply to the portion of the opening of the positive electrode can that is in contact with the gasket. After applying the conductive paint with a spray gun, the solvent is evaporated by a dryer.
The thickness of the remaining conductive film is desirably about 1 to 10 μm. FIG. 5 shows the configuration of the plating layer of this positive electrode can. In FIG. 5, reference numeral 12 denotes a conductive film.

Using the obtained positive electrode can, an LR6 type (AA) alkaline dry battery as shown in FIG. 1 was assembled in the same manner as in Example 1. As described above, a nickel-phosphorus alloy plating layer having a thickness of 1 to 2 μm is formed on the inner surface side of the positive electrode can, a nickel-phosphorus plating layer having a thickness of 1 to 2 μm is formed thereon, and further thereon. A conductive coating is formed.

Example 4 A positive electrode can manufactured in the same manner as in Example 3 was used in the same manner as in Example 3 except that no conductive coating mainly composed of graphite powder was formed on the inner surface thereof. To assemble a JIS standard LR6 type AA alkaline battery.

The alkaline dry batteries of Examples 3 and 4 and the alkaline dry batteries of Comparative Examples 1 to 4 were stored at 60 ° C. for 0, 10, and 60 days.
The internal resistance and discharge capacity at 20 ° C. were examined, and the results are shown in Table 2. The internal resistance (mΩ) of each battery 10
The samples were measured using a 1 kHz AC resistance meter, and their average values were shown. As for the discharge capacity, a 2Ω continuous discharge test was performed on each of 10 batteries, and the average value of the duration (min) up to a final voltage of 0.9 V was shown.

[0030]

[Table 2]

As is clear from the above table, Examples 3 and 4 showed a small increase in the internal resistance of the battery even after storage at 60 ° C. for 60 days and a decrease in the discharge capacity as compared with Comparative Examples 1 to 4. It can be seen that the deterioration is small.

[0032]

As described above, the alkaline dry battery of the present invention has high capacity, excellent heavy load characteristics, and excellent storage characteristics.

[Brief description of the drawings]

FIG. 1 is a sectional view of an alkaline dry battery according to one embodiment of the present invention.

FIG. 2 is a layer configuration diagram of a positive electrode can in an example of the present invention.

FIG. 3 is a diagram showing a layer structure of a positive electrode can in another embodiment of the present invention.

FIG. 4 is a layer configuration diagram of a positive electrode can in another embodiment of the present invention.

FIG. 5 is a layer configuration diagram of a positive electrode can according to another embodiment of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Positive electrode can, 2 ... Positive electrode mixture, 3 ... Separator, 4 ... Gelled zinc negative electrode, 5 ... Negative electrode current collecting rod, 6 ... Insulating gasket, 7
... ring-shaped metal plate, 8 ... metal sealing plate, 9 ... cold-rolled steel plate material, 10 ... nickel plating layer, 11 ... nickel-phosphorus plating layer, 12 ... conductive coating layer mainly composed of graphite powder,
13. Nickel-phosphorus alloy plating layer.

Claims (6)

[Claims] 1. A bottomed cylindrical positive electrode can also serving as a positive electrode terminal,
An alkaline dry battery including a hollow cylindrical positive electrode mixture disposed in the positive electrode can and a gelled zinc negative electrode filled in the hollow portion of the positive electrode mixture via a bottomed cylindrical separator, As a can, a nickel-plated layer was previously formed on both sides of a cold-rolled steel sheet.
An alkaline dry battery using a can formed by forming a phosphor plating layer and pressing and drawing so that the surface becomes an inner surface. 2. The alkaline dry battery according to claim 1, wherein a conductive coating mainly composed of graphite powder is formed on the inner surface of the positive electrode can. 3. The graphite powder content in the positive electrode mixture is 8 wt%.
The alkaline dry battery according to claim 1 or 2, wherein 4. A positive electrode can having a bottomed cylinder also serving as a positive electrode terminal,
An alkaline dry battery including a hollow cylindrical positive electrode mixture disposed in the positive electrode can and a gelled zinc negative electrode filled in the hollow portion of the positive electrode mixture via a bottomed cylindrical separator, As a can, a cold-rolled steel sheet having a nickel-phosphorous plating layer formed on both surfaces in advance is post-processed to further form a nickel-phosphorus alloy plating layer between the steel sheet and the nickel-phosphorous plating layer, and then press-drawn and ironed. Alkaline dry battery characterized by the use of a can. 5. The alkaline dry battery according to claim 4, wherein a conductive coating mainly composed of graphite powder is formed on an inner surface of the positive electrode can. 6. The graphite powder content in the positive electrode mixture is 8 wt%.
The alkaline dry battery according to claim 4 or 5, wherein