Low-cost and high-quality lithium ion battery membrane coating technology

Abstract

The invention provides a low-cost and high-quality lithium ion battery membrane coating technology. The technology includes the following steps that base membrane unrolling is conducted, wherein a polyethylene or polypropylene membrane serves as a base membrane, the base membrane is put on an unrolling machine to be unrolled, the thickness specification of the base membrane ranges from 9 microns to 40 microns, the porosity ranges from 30% to 70%, and the unrolling speed of the base membrane is 40 m / min; and base membrane stress relieving is conducted, wherein the base membrane which is not coated enters a stress relieving hot drying oven through guide rollers, the five guide rollers are arranged in the hot drying oven at equal intervals in a manner that two of the guide rollers are arranged at the upper portion, and three of the guide rollers are arranged at the lower portion, the staying time of the membrane in the hot drying oven ranges from 2 s to 15 s, and electric heating circulation hot air is used for heating. By means of the low-cost and high-quality lithium ion battery membrane coating technology, a membrane stress relieving and deviation rectifying device can be added tothe front end to improve spreadability of the membrane, in addition, energy consumption can be reduced by means of a waste heat reusing strategy of the drying stage, in addition, losses and waste of base membranes and slurry can be reduced through a newly-added roll changing device, and therefore the membrane coating cost is reduced.

Description

technical field [0001] The invention relates to the technical field of manufacturing lithium-ion batteries, in particular to a low-cost and high-quality lithium-ion battery diaphragm coating process. Background technique [0002] As one of the important components inside the lithium-ion battery, the diaphragm can not only isolate the positive and negative electrodes to prevent short circuit, but also allow lithium ions to pass through freely. Its high-temperature melting characteristics make it one of the important factors that determine the safety of lithium-ion batteries. The importance of separators in Li-ion batteries is self-evident. At present, the commonly used materials for the preparation of lithium-ion battery separators in the market are mainly polyolefin (polyethylene or polypropylene) materials, and their melting point range is only 130-180°C. Lithium-ion batteries, especially power-ion batteries, instantly A lot of heat will be released. In order to further en...

AI Technical Summary

Problems solved by technology

At present, the commonly used materials for the preparation of lithium-ion battery separators in the market are mainly polyolefin (polyethylene or polypropylene) materials, and their melting point range is only 130-180°C. Lithium-ion batteries, especially power-ion batteries, instantly A lot of heat will be released. In order to further ensure the safety of lithium-ion batteries, a layer of nano-inorganic ceramic materials that can deform in volume at high temperatures is generally coated on the surface of polyolefin separators. The treatment process of coating the ceramic layer is referred to as diaphragm coating. The quality of the coating effect in the current common coating process is closely related to the quality of the diaphragm. The internal stress and thickness uniformity of the diaphragm have a good coating effect. If the diaphragm If the thickness is uneven or the diaphragm is wrinkled, the base film will deviate or the coating will be uneven during the coating process. In addition, when the base film roll is replaced during the diaphragm coating, it is often necessary to stop the car and drive again. A stabilization period during which the diaphragm and coating slurry are wasted, increasing the cost of diaphragm coating

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