CS238401B1 - ) Method of production of conductive collectors of electrodes of electrochemical sources - Google Patents

Abstract

The conductive collector according to the subject of the invention is produced by plating a metal mesh with a direct electric current in a solution of metal salts while simultaneously seeding the growth of active centers on the plated mesh with an admixture of metal powders.

Description

The invention solves a method of producing conductive collectors for electrochemical sources.

Current methods of increasing the surface of collector networks use galvanic or metallization processes or mechanical roughening. Surface enlargement is achieved, for example, by electroplating a steel or nickel mesh with a thick layer of nickel or a mixture thereof with another metal. This layer can be mechanically roughened by sandblasting or pickling in a further operation. The nickel can also be sprayed onto the collector net at high temperatures or sprayed in a mixture with a binder and subsequently fired. Another method is to deposit nickel compounds which are thermally decomposed and sintered in a subsequent operation. The nickel powder can be adhered to the grid electrostatically or electromagnetically and then thermally sintered. It is also possible to apply a rough nickel layer in a plasma manner. The surface of the steel or nickel mesh may also be roughened by a vacuum-vaporized nickel layer or a mixture thereof with another metal. It is also possible to roughen the collector surface before applying the nickel layer by sandblasting or chemical pickling.

However, in the above electrochemical processes, only slight surface enlargement is achieved and, moreover, the methods are very expensive or technology intensive.

These drawbacks are eliminated by the collectors produced by the process according to the invention.

It is based on the fact that electroplating is carried out in the electroplating bath by an electric direct current, but at the same time inoculating the growth of the active centers on the metallized surface by the addition of a metal powder. According to the invention, the inoculum admixture is maintained during electrolytic deposition by intermittent stirring, circulation or introduction of the gaseous medium into the plating medium, by bubbling.

By increasing the surface of the metallized network with a dendridic metallic conductive material, a conductive but also mechanical improvement of the electrode is guaranteed so that higher currents can be used for discharging and charging. Increasing the active surface of the metallized network as a collector of electrodes with a dendridic metal material results in a significant prolongation of the life of the electrochemical source.

Example of rough collector plating:

The metal mesh is plunged vertically into the plating bath in a direct current connection as a cathode, between the two flat metal anodes to be metallized. Buying! The gas is added to the bath to float. A similar effect can be achieved by a vortex mixer or by circulation of a solution through a pump. The powdery metal that floats rests on the metallized mesh, where it immediately begins to be coated with a layer of precipitated metal and is also an active center for the growth of subsequent sharp dentrides.

Example of bath composition:

Nickel sulphate NiSCU 150 g. I “ ¹

Magnesium sulphate MgSCU 25 g. I “ ¹

Sodium sulphate Over 75 gl ¹

Vaccination: nickel powder 4.0 g. 1 ^_1

Current density Elimination time Bath pH Temperature Cathode

anode

250 A. m ^-2 60 min

2,5 40 ° C nickel-plated iron mesh nickel sheet

The electrodes with the collector produced in this way show up to 20% reduction of the internal resistance compared to the previously produced ones, and in the charging and discharging tests they exhibit many times longer lifetime than the electrodes with conventional collectors.

Claims (1)

SUBJECT A method for producing conductive electrode collectors of electrochemical sources by electrochemically plating a metallic mesh, characterized in that the growth of the active centers on the metallized mesh is inoculated by adding powdered metal to the plating bath, wherein the powdered metal is maintained during electrochemical plating in either intermittent mechanical stirring intermittent circulation or by intermittent bubbling of a gaseous medium such as air, nitrogen, carbon dioxide and the like.