JPH04253157A - Manufacture of electrode plate for nickel-cadmium storage battery - Google Patents

Abstract

PURPOSE:To knead high-viscosity paste and uniformly disperse it by pressurizing and kneading the powder constituting an electrode, fibers, a binder and a kneading liquid with a kneading machine having Banbury type kneading blades. CONSTITUTION:The kneading time differs according to the stocked quantity, rotating speed and power, and it is 1.5 hr for a positive electrode and 3 hr for a negative electrode. In the pressurization type 5 kneading, paste 3 uniformly dispersed by the compression action is obtained. The powder in the paste 3 can be set to 75wt.% or above for the positive electrode and 80 wt.% or above for the negative electrode for kneading, and the high-density paste can be obtained. The paste is kneaded by a kneading machine with a pressurizing system having Banbury type kneading blades, thus the high-density paste with a reduced kneading liquid is obtained, and fibers or metal cadmium can be uniformly dispersed in the paste 3.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing nickel-cadmium storage battery plates.

0002

[Prior Art] Conventionally, nickel-cadmium storage battery electrode plates have been produced using a sintering method in which a porous nickel sintered substrate is filled with active material by electrolytic deposition or chemical impregnation, or by kneading the active material into a paste and applying it to the substrate. Manufactured using a paste method. Among these, the paste type is suitable for increasing the capacity of storage batteries. A spiral mixer called a universal kneader is used for the kneading. Currently, the paste type is in practical use as a cathode, and the properties of the kneaded product have a viscosity of 1 x 105 to 2 x 105 CP.
S, in the form of a slurry with a density of 3.6 g/cm3. To increase the capacity of storage batteries, it is necessary to reduce the amount of kneading liquid and create a paste with higher density.

0003

Problems to be Solved by the Invention In order to achieve high capacity, the paste is consolidated and its viscosity becomes 8×10 6 CPS or more. In the anode, nickel-plated carbon fiber is added to the main component, nickel hydroxide, to improve conductivity. At the cathode, metal cadmium is added to the main component, oxidized cadmium, for non-chemical assembly. Therefore, in addition to increasing the viscosity,
Fibers that tend to aggregate and are difficult to disperse and metal cadmium powder, which dislikes the activation atmosphere and whose particle size distribution varies from 1.0 to 50 μm, must be uniformly dispersed in the paste. Spiral mixers only have dispersion power, that is, the ability to stir, and cannot simultaneously knead and disperse a highly viscous kneaded material.

[0004] Furthermore, the weight percentage of powder in the anode is 60%.
Below, when the weight percent of the powder at the cathode is set to 70% or less and the kneading liquid is increased, kneading using a spiral mixer becomes possible. However, the kneaded material becomes a slurry state and cannot be densified.

[0005]

[Means for Solving the Problems] The present invention has been made to achieve the above-mentioned object. The mixture is kneaded under pressure.

[0006]

[Operation] The shape of the kneading blades and the pressurizing mechanism provide a compression effect and a grinding and dispersion effect, making it possible to knead high-viscosity paste. At the same time, fibers or metal cadmium are uniformly dispersed into the paste.

[0007]

[Example] A typical kneading blade of a kneading machine is a Σ type. Figure 1
(a) shows a Σ-type kneading blade, and FIG. 1(b) shows a Banbury-type kneading blade. When kneading the paste 3 with a high capacity, the Σ type does not have enough compressive force and the dispersibility becomes poor. In anode pastes that are highly affected by compression, the packing density on the substrate is Σ-shaped and is 59
0mAh/cm3, 600mAh/cm for banbari type
It becomes 3. Further, there are two types of kneading machines: an open type 4 and a pressurized type 5. 6 is a kneading machine, and 7 is a pressurizing lid. FIGS. 2 and 3 show schematic diagrams of the kneading state of both.

[0008] The kneading time varies depending on the amount charged, the number of revolutions, and the power, but it is 1.5 hours for the anode and 3 hours for the cathode. When kneading is performed using the pressure type 5 shown in FIG. 2, a uniformly dispersed paste 3 is obtained due to the compression action. On the other hand, in the open type 4 shown in FIG. 3, the kneaded material cannot be pressed down and it scatters and does not become paste-like.

[0009] With this kneader having Banbury-type kneading blades and a pressurizing mechanism, an anode of 2.5 g/cm3 and a cathode of 4.1
A paste of gcm3 can be obtained.

[0010] The average particle size of the powder in the active material is 11 in the anode.
Nickel hydroxide of ~15 μm, metallic cobalt of 5-7 μm, and cobalt compound of 6-7 μm are used, and cadmium oxide with an average particle size of 1-4 μm and metal cadmium of 2-10 μm are used at the cathode.

[0011] Furthermore, it is possible to knead the powder in the paste at a weight percentage of 75% or more at the anode and 80% or more at the cathode,
It becomes possible to increase the density of the paste.

In the anode, the average particle size of the powder is 11 to 15 μm using nickel hydroxide, and the smaller particle size is 5 to 7 μm.
By adding metal cobalt of m and 6 to 7 μm of a cobalt compound, it becomes possible to further increase the density. For the cathode, it becomes possible to use metal cadmium, which has large variations. That is, cadmium oxide with an average particle size of 1 to 4 μm, 2 to 1
By using metal cadmium with a thickness of 0 μm, it is possible to achieve even higher density.

[0013]

[Effects of the Invention] As described above, according to the present invention, the paste is kneaded by a kneader having a pressurizing mechanism equipped with Banbury-type kneading blades, so that the kneading liquid is reduced and the density is increased. A paste can be obtained and the fibers or metal cadmium can be uniformly dispersed in the paste.

[Brief explanation of the drawing]

FIG. 1 shows kneading blades in an active material paste kneading device, in which (a) is a Σ-shape and (b) is a Banbury-shape.

FIG. 2 is an explanatory diagram showing a state of paste kneading by a pressurized type.

FIG. 3 is an explanatory diagram showing a state of paste kneading by an open type.

[Explanation of symbols]

1 is a Σ-type kneading blade, 2 is a Banbury-type kneading blade, 3 is a paste, 4 is an open type, 5 is a pressurized type, 6 is a kneader, and 7 is a pressurized lid.

Claims (1)

[Claims] Claim 1: Powder, fiber, binder constituting an active material, and 1
A method for producing a nickel-cadmium storage battery electrode plate, which comprises kneading 6 to 18% by weight of a kneading solution using a kneader having Banbury-shaped kneading blades and a pressurizing mechanism.