Lithium ion power battery membrane stress treatment device

Abstract

The invention discloses a lithium ion power battery membrane stress treatment device. The lithium ion power battery membrane stress treatment device comprises a heat radiation chamber, far infrared directional radiation heaters, compressed air knifes, guiding rollers, winding rollers and a membrane traction device. The corresponding far infrared directional radiation heater and the corresponding compressed air knife are arranged on the top of an inner cavity of the heat radiation chamber, and the corresponding far infrared directional radiation heater and the corresponding compressed air knifeare also arranged at the bottom of the inner cavity of the heat radiation chamber. The first guiding roller, the first winding roller, the second winding roller and the second guiding roller are sequentially arranged at the middle portion of the inner cavity of the heat radiation chamber. The membrane traction device is arranged on one side of the heat radiation chamber. Through heating treatmentof the stress treatment device, inner stress of a battery membrane can be effectively removed, low inner stress membrane materials are obtained, the performance defect of stress concentration of a commercial polyolefins membrane is effectively overcome, and accordingly safety performance and rate performance of lithium ion batteries are improved.

Description

technical field [0001] The invention relates to the field of lithium-ion battery materials, in particular to a stress treatment device for a diaphragm of a lithium-ion power battery. Background technique [0002] As a key material for the production of lithium-ion batteries, the diaphragm has an important impact on the actual performance of the battery. For example, the diaphragm has the function of electronic insulation, which can avoid short circuits inside the battery; provide channels for ion transfer to ensure the smooth progress of electrochemical reactions; Under certain conditions, the separator can block the transmission of lithium ions through closed cells to prevent safety accidents. [0003] At present, the lithium-ion battery separators that have achieved large-scale commercial production are all polyolefin separators. During the production process, the separator material needs to be physically stretched multiple times with different strengths through equipment,...

AI Technical Summary

Problems solved by technology

[0003] At present, the lithium-ion battery separators that have achieved large-scale commercial production are all polyolefin separators. During the production process, the separator material needs to be physically stretched multiple times with different strengths through equipment, and the tension is the main force. As a result, the diaphragm material has accumulated a large amount of internal stress and has no place to release it. The stress of the diaphragm is mainly due to the accumulation of polyolefin polymer raw materials when they change from solid to liquid during the hot-melt process, and are continuously stretched during the production process. There is no buffer and rebound device or process, resulting in nowhere to release the tensile stress stored in the internal structure of the material

The existence of stress will make the diaphragm material prone to cracking, warping, and even product size changes. If such a diaphragm with strong internal stress is applied to battery assembly, it will cause the diaphragm to shrink severely during the electrochemical process. Deformation, affecting the safety performance of the battery

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