Double-sided extrusion coating method and coating device suitable for microporous base material

Abstract

The invention relates to a double-sided extrusion coating method and a coating device suitable for a microporous base material. The coating device comprises a traction system, a first extrusion coating head and a second extrusion coating head, wherein the first extrusion coating head is arranged on one side of the microporous base material and is not in contact with the microporous base material; the second extrusion coating head is arranged on the other side of the microporous base material; a lower lip of the second extrusion coating head is in contact with the microporous base material in a linear contact or area contact manner; the second extrusion coating head is used for intermittently coating slurry on a base material in the direction intersecting with the moving direction of the microporous base material; the first extrusion coating head and the second extrusion coating head are arranged near the opposite positions, and are isolated by the microporous base material; the first extrusion coating head is used for coating the slurry on the line contact or area contact part of the lower lip of the second extrusion coating head and the microporous base material. The method has the advantages that double-sided coating of the microporous base material can be realized; the problem that the coatings on the double sides of the base material have different viscosity and the problems that the slurry remains on a coating roller and the base material is pierced by dry coatings are avoided.

Description

technical field [0001] The invention relates to a double-sided extrusion coating method and a coating device suitable for microporous substrates, in particular to a double-sided extrusion coating method and coating device suitable for microporous substrates in the production process of lithium batteries. Background technique [0002] The production of lithium batteries generally includes positive electrode substrates, negative electrode substrates and separators, and the production of positive electrode substrates and negative electrode substrates is inseparable from the coating process. Existing coating methods are divided into coating roller batch coating method and extrusion coating method. The extrusion method is welcomed by users because of its high coating precision and easy control. [0003] At present, extrusion coating is used to coat both sides of the substrate. Generally, there are two methods. One is to coat one side of the substrate first, and then coat the ...

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Problems solved by technology

Although the adhesion on both sides of the coating is better than the first method above, there is still the problem that the adhesion is not completely consistent; at the same time, some paint will remain on the coating roller, and the coating roller needs to be cleaned regularly. ; There is also a third problem in the latter, because the second coating head is located on the underside of the substrate between the coating roller and the inlet of the oven (generally near the inlet of the oven), so that the residue on the lower surface of the substrate The coating will gather on the side of the second coating head close to the coating roller, which will affect the coating quality of the second coating head, and the problem of unstable coating thickness will occur. In severe cases, the dried coating will still Will puncture the substrate, resulting in defective coatings

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