Diaphragm with low hole closing temperature and preparation method thereof

By using specific formula polyethylene raw materials and bidirectional stretching process, the closed-cell temperature of the lithium battery separator is reduced, the risk of heat heating and explosion in the battery is solved, and safer and more efficient battery performance is achieved.

CN119905774AInactive Publication Date: 2025-04-29康辉南通新材料科技有限公司
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Patent Information

Application Number
CN202510380045.4
Authority / Receiving Office
CN · China
Patent Type
Applications(China)
Current Assignee / Owner
Filing Date
2025-03-28
Publication Date
2025-04-29
Estimated Expiration
Not applicable · inactive patent

AI Technical Summary

Technical Problem

The prior art is difficult to effectively reduce the closed-cell temperature of the lithium battery separator at a lower temperature, resulting in the risk of heat heating and explosion in the battery.

Method used

Specific PE raw material formulas are adopted, including polyethylene A with a viscosity average molecular weight of 1 million to 1.5 million, polyethylene A with a viscosity average molecular weight of 1 million to 600,000, and polyethylene C with a viscosity average B with a viscosity average B and 300,000 to 400,000, and polyethylene C with a bidirectional stretched diaphragm preparation process, and the extrusion, stretching and winding processes are optimized to reduce the closed pore temperature of the diaphragm.

Benefits of technology

The closed-cell temperature of the lithium battery separator is successfully reduced to below 130°C, reducing the risk of explosion caused by violent temperature rise in the battery, and improving the strength and fluidity of the separator.

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Abstract

The invention relates to the technical field of lithium battery diaphragms, and particularly discloses a low-hole-closing-temperature diaphragm and a preparation method thereof. The preparation raw materials of the diaphragm with the low hole closing temperature are prepared by mixing three different PE materials, and the hole closing temperature of the base diaphragm can be reduced to 130 DEG C or below by adopting a PE raw material formula with specific composition and matching with a biaxial stretching diaphragm preparation process, so that the diaphragm is subjected to hole closing at a relatively low temperature, and continuous temperature rise of heat in a battery is avoided; and the risk of explosion caused by severe temperature rise of the battery is reduced.
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Citation Information

Patent Citations

  • Diaphragm with low hole closing temperature and preparation method thereof

    CN116259924A

  • Polyethylene microporous film for nonaqueous battery separator

    JP1996064194A

  • Polyolefin microporous membrane

    JP2003183432A

Cited By

  • Lithium battery diaphragm with reversible thermal hole closing function and preparation method thereof

    CN121238156A

  • Low-closed-pore diaphragm, preparation method thereof and secondary battery

    CN121460860A