JP2546638B2 - Manufacturing method of battery plate - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for manufacturing a battery electrode plate.

(Prior Art) Conventionally, an alkaline storage battery is a typical one in which a sponge-like metal is applied to an active material holder of a battery electrode plate. A method has been proposed in which a kneading active material of a powdery active material mixture and a thickening agent is mechanically filled and then pressurized.

However, since the average pore diameter of the sponge-like metal that is usually used is 10 times or more the average pore diameter of the sintered metal obtained by sintering nickel powder, gas generation during charging and discharging of the storage battery Causes the active material to fall off, which is more pronounced than in the case of sintered metal.

Therefore, there is a drawback in that the battery performance is deteriorated due to a decrease in the battery capacity or a short circuit inside the battery.

In order to eliminate this defect, a wire brush is applied to the surface of the sponge-like metal electrode body filled with the active material, the active material in the surface layer is removed to expose the sponge-like metal, and then 500 to 1000 kg / It has been proposed to apply a high pressure of about cm ² to obtain a desired electrode.

(Problems to be Solved by the Invention) However, in the method of subjecting the exposed sponge-like metal to a pressure treatment, an extra step of removing a part of the active material once filled is required again, Therefore, there is a drawback that the cost is increased due to the loss of raw materials and the introduction of extra steps.

(Means for Solving Problems) The present invention aims to solve the above-mentioned drawbacks of the conventional method and to provide a method for producing a battery electrode plate in which the dropping of the filling active material is suppressed. In a method for manufacturing a battery electrode plate using a sponge-like porous metal body having an original reticulated structure as a current collector structure,
After making the average pore size near the surface of the porous metal body smaller than the internal average pore size by applying skin pass rolling a plurality of times,
Filling with active material.

(Example) Here, skin pass rolling in the present invention will be described first, which is a stage before filling an electrode plate with an active material,
This means that a sponge-like porous metal plate having a uniform average pore size and a thickness larger than the final desired thickness is lightly rolled several times to the desired electrode plate thickness (hereinafter referred to as skin pass rolling).

In this way, when skin pass rolling is performed on a sponge-like metal porous body, unlike ordinary press pressing and rolling, in the case of a very low density object of sponge-like metal, the displacement of the object due to pressure stress load is This occurs only in the layer portion, and as a result, the pore diameter of only the surface layer of the sponge-like metal is reduced.

Therefore, microscopically observing the cross section of the skin-pass-rolled sponge-like metal in the present invention, the pore diameter changes in the thickness direction, and the pore diameter of the surface layer is smaller than that of the inside. Is recognized.

 Next, specific examples of the present invention will be described.

The material is nickel, (1) thickness 1.5mm, average pore size 1
Two kinds of sponge-like porous metal sheets having a thickness of 60 μm, (2) a thickness of 1.0 mm, and an average pore diameter of about 160 μm were prepared as current collecting structures for the electrode body.

First, a sponge-like porous metal sheet having a thickness of 1.5 mm was subjected to rolling to produce a porous body having a thickness of 1.0 mm.

Table 1 shows the results of the rolling process. Sample No. 1 and No.
2 is a porous sheet according to the present invention, No. 1 is 1.5 mm thick
No. 2 is a sponge sheet having a thickness of 1.5 mm, and the sponge sheet is subjected to skin pass rolling three times.

Sample No. 3 shows a comparative example, in which a sponge-like sheet having a thickness of 1.5 mm is rolled to a thickness of 1.0 mm by one-pass rolling.

Sample No. 4 is a conventional sponge-like porous sheet having a thickness of 1.0 mm, which has not been subjected to rolling processing.

Next, the sponge-like porous sheets of Samples No. 1 to No. 4 shown in Table 1 were mechanically filled with a paste-like active material composed of nickel hydroxide, nickel powder, CMC and water to form a nickel positive electrode plate. Obtained. The filling amount of the active material was 1.78 g /
It was cc.

By combining this nickel positive electrode plate and a cadmium negative electrode having a capacity equivalent to 160% of the theoretical capacity of the positive electrode, a C type cylindrical sealed battery was produced and a charge / discharge cycle life test of the battery was conducted.

FIG. 1 shows the relationship between the number of charge / discharge cycles and the discharge capacity of the battery.

In the figure, curves No. 1 and No. 2 are batteries using the electrode plate of the embodiment of the present invention, and curves No. 3 are 1.0 mm thick when the sponge-like porous sheet having a thickness of 1.5 mm is rolled for one pass. The curve No. 4 shows the characteristics of the battery using the sponge-like porous sheet as described above, and the curve No. 4 shows the characteristics of the cell as it is, that is, the battery using the sponge-like porous sheet with a thickness of 1.0 mm without skin pass.

From FIG. 1 produced by plotting the test results, the battery using the electrode plate of the present invention has a smaller capacity decrease in the charge / discharge cycle test than other conventional batteries and comparative batteries, and therefore It can be seen that the battery using the electrode plate of the invention has excellent life characteristics.

(Effects of the Invention) As described above, according to the present invention, in a method for producing a battery electrode plate using a sponge-like porous metal body having a three-dimensional network structure as a current collector structure, the porous layer is formed by applying skin pass rolling multiple times. Since the active material is filled after making the average pore size near the surface of the metal body smaller than the internal average pore size, the step of removing the filling paste active material of the surface layer as in the prior art is unnecessary, and therefore the active material is not necessary. Since there is no loss, the cost can be reduced. Since the pore size of the manufactured electrode plate is smaller in the surface layer than in the interior, the active material is prevented from falling off, and the active material utilization rate is improved. .

[Brief description of drawings]

The drawings are graphs showing charge / discharge cycle test results of a storage battery using the electrode plate of the example of the present invention and a storage battery using the comparative example electrode and the conventional example electrode.

Claims (1)

(57) [Claims] 1. A method for manufacturing an electrode plate for a battery, comprising a sponge-like porous metal body having a three-dimensional network structure as a current collecting structure, wherein an average pore diameter in the vicinity of the surface of the porous metal body is increased by applying skin pass rolling a plurality of times. The method for producing an electrode plate for a battery, which comprises filling the active material after making the average pore size smaller than the average pore size.