Method for solving wrinkle of dried separator of lithium ion battery

Abstract

The invention provides a method for solving wrinkle of a dried separator of a lithium ion battery. The method comprises a first scheme or a second scheme. The first scheme comprises the following steps of pouring a solvent into a processing pool, maintaining constant temperature of the processing pool and constant height of a liquid level, immersing the separator before cutting in the solvent, allowing the separator to pass through the processing pool at a constant speed, performing drying, and obtaining after drying is completed. The second scheme comprises the following steps of pouring thesolvent into the processing pool, maintaining constant temperature of the processing pool and constant height of the liquid level, immersing a battery lamination piece or the separator before windingin the solvent, allowing the separator to pass through the processing pool at the constant speed, performing drying, and obtaining after drying is completed. The solvents in the first scheme and the second scheme are same or different. The method for solving the wrinkle of the dried separator of the lithium ion battery is relatively wide in processing time and temperature control range, the selection surface of the processing solvent is relatively wide, the solvent can be recycled, and the process is simple and is relatively mature.

Description

Technical field [0001] The invention belongs to the field of lithium ion batteries, and in particular relates to a method for solving the wrinkles of lithium ion battery dry-process diaphragms. Background technique [0002] In recent years, with the increasing awareness of global energy conservation and environmental protection, new energy vehicles, which represent the direction of future automobile development, are gradually being accepted by consumers, and the development of the industry has gradually become more formal. In order to ensure that new energy vehicles have long-term market competitiveness, improving quality and reducing costs is still the direction that the entire industry needs to work together. As the core component of new energy vehicles, the cost control of power battery is particularly important. As one of the four main materials, the diaphragm material has a greater impact on the overall price of the battery. Among them, the dry diaphragm has high processing ...

AI Technical Summary

Problems solved by technology

[0004] At present, the problem of wrinkling of dry-process diaphragms is relatively common, and it also affects the large-scale use of dry-process diaphragms to a certain extent.

The main reason is that the dry-process separator is anisotropic, and the stress release is uneven during the electrolyte infiltration process and cannot be eliminated in time to cause wrinkles

In order to improve the wrinkle problem of the dry-process separator, the separator production plant adopts raw material adjustment, heat treatment, and stretching process optimization to improve the tension problem, but the improvement effect of uneven tension release after the separator contacts the electrolyte is not obvious; each battery factory mainly uses the gel technology to improve the tension problem. The bonding of the diaphragm and the pole piece prevents stress release. Firstly, the polymer coating is introduced, which increases the manufacturing cost of the diaphragm. Second, the hot pressing process with strict temperature control is introduced, which increases the battery manufacturing cost. Finally, the polymer coating increases the internal resistance of the battery. Electrical properties are also adversely affected

Images