Preparation method of nickel electrode

Abstract

The invention discloses a preparation method of a nickel electrode. The method includes the following steps that: S1, a porous nickel substrate is selected and is subjected to one-time rolling; S2, afilling device is adopted to perform primary filling; S3, at least one set of scrapers A is utilized to perform secondary filling, each set of scrapers A includes two scrapers A disposed symmetricallywith respect to the central axis plane of the porous nickel substrate, the scrapers A are coupled with elastic components such that the scrapers A, in operating states, can move in a direction perpendicular to the surface of the porous nickel substrate, so that an effect applied onto the porous nickel substrate by the scrapers A satisfies an inequality that Pd/P0<=10%; and S4, secondary rolling is performed, so that a nickel electrode of a target thickness is obtained. According to the preparation method of the invention, an active material can be made to be in a stable full state under the action of the secondary filling of the scrapers A which is approximate to equal-pressure filling; and the per-unit-area filling uniformity of the nickel electrode obtained through the preparation method of the present invention is high; the per-unit-area weight fluctuation of the nickel electrode is small; and the nickel electrode has a broad application prospect in the battery field.

Description

technical field [0001] The invention relates to the field of electrodes, in particular to a method for preparing a nickel electrode. Background technique [0002] As a reversible electrode with excellent electrochemical performance, nickel electrode is widely used in the positive electrode of alkaline secondary batteries, such as common nickel-metal hydride batteries, nickel-zinc batteries, nickel-cadmium batteries, etc. At present, the widely used nickel electrodes are mostly made of mixed hydroxide powder containing nickelous hydroxide as the active material filled in the foamed nickel matrix and compacted, and the particle size of the active material is 5-25 μm. Mainly within the range, the foamed nickel substrate is the equivalent pore diameter (that is, the average diameter of the three-dimensional hole woven by nickel wire, and the diameter of the hole on each surface of the woven space hole is smaller, about 1 / 4 of the diameter of the space hole ) is about 400-800 μm...

AI Technical Summary

Problems solved by technology

However, whether it is dry filling or wet filling, only the fluidity of the filling active material is different, and the spatial cavity structure of the foamed nickel matrix is ​​not changed, so the filling uniformity has not been fundamentally improved, especially The step fluctuation before and after the substrate passes through the joint is still

On the other hand, dry filling depends on the powder fluidity of active material dry powder, because it depends on the sphericity and surface smoothness of spherical nickel hydroxide, so the powder fluidity of dry powder is low but relatively stable; wet filling depends on The fluidity of the suspension or wet paste prepared by active substances, thickeners, water, etc. The state of the aqueous slurry is complex and changeable. Denaturation, film-forming properties, etc. are affected by many factors, and all of them will strongly affect the uniformity of filling, so the state of water-based slurry varies greatly. The filling uniformity of the method may be better than that of the dry method, but not all wet methods are better than the dry method. Once the wet method is abnormal, the filling uniformity will be greatly deteriorated, and it will even be so serious that it cannot be filled. gelled

Therefore, for the filling uniformity, the dry method and the wet method have their own advantages and disadvantages, and neither can fundamentally solve the problem of filling uniformity. Also, the nickel electrode based on fiber nickel also has the problem of uneven filling when filling the active material. question

[0005] In summary, nickel electrodes based on porous nickel substrates such as foamed nickel and nickel fibers have poor feeding uniformity in the form of weight fluctuations. The main reason is that the spatial pore structure of the nickel substrate affects the filling uniformity of the active material. an ideal solution

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