Metal porous body and making method thereof, current collector for cell having same

Abstract

A metallic porous body that is free from clogging in the filling process of an active material, that allows the active material to fill the body uniformly even to the deep inside, and that thereby enables a secondary battery to combine large battery capacity and a high output; a method of manufacturing the metallic porous body; and a current collector having the metallic porous body. The metallic porous body is composed of a metallic framework having a three-dimensional network with a continuous-pore structure formed by linking substantially polyhedral cells. The substantially polyhedral cells have an average cell diameter of 200 to 300 µ m and an average window diameter of 100 to 200 µm. The metallic porous body can be obtained by the following method, for instance: First, a plastic porous body is provided that has an average cell diameter of 200 to 300 µm and an average window diameter of 100 to 200 µm. Second, a conductive layer is formed on the surface of the framework of the plastic porous body to produce a conductive porous body having a resistivity of 1 k©·cm or less. Finally, a continuous metalplated layer is formed on the surface of the conductive layer by electroplating, with the conductive porous body serving as the cathode. The above-mentioned current collector is provided by filling an active material into the pores of the metallic porous body.

Description

technical field [0001] The present invention relates to a metal porous body including a metal frame for alkaline batteries (such as nickel-cadmium batteries, nickel-hydrogen batteries and nickel-zinc batteries) and a method for manufacturing the metal porous body, and a metal porous body having the same current collector. Background technique [0002] As current collectors for alkaline batteries, sponge metals and sintered metals are widely used. [0003] Sponge metals are composed of a metal framework having a three-dimensional network structure with a continuous microporous structure formed by connecting cells that are substantially polyhedral. Because the porous metal has a porosity as high as 90%-98%, the amount of active material charged per unit volume can be increased; therefore, the advantage is that the current collector can have a high capacity density (mAh / cc). [0004] The porosity of sintered metal is not greater than about 85%, which is worse than that of spo...

AI Technical Summary

Problems solved by technology

[0008] However, using conventional methods to reduce the diameter of the substantially polyhedral cells results in a simultaneous reduction in the size of the windows present in the inner cells visible through the openings of the polyhedral cells on the sponge-like metal surface.

[0009] The problem caused by the reduction in the size of the window in the inner chamber is that the window is easily blocked during the process of filling the active material, and it is difficult to uniformly fill the active material into the sponge metal.

These problems will cause serious problems of cracks in the subsequent rolling process and reduce the final capacity of the battery

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