Diaphragm and preparation method thereof as well as lithium ion battery

A lithium-ion battery and diaphragm technology, which is applied in the direction of secondary batteries, battery pack components, circuits, etc., can solve the problem that the battery cannot achieve high-rate discharge, and achieve good high-rate discharge characteristics, good liquid absorption, and production technology simple effect
CN101471432BInactive Publication Date: 2012-11-21BYD CO LTD
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Patent Information

Authority / Receiving Office
CN · China
Patent Type
Patents(China)
Current Assignee / Owner
BYD CO LTD
Publication Date
2012-11-21
Estimated Expiration
Not applicable · inactive patent

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Abstract

A diaphragm is selected from a composite membrane containing polyethylene terephthalate membrane as the base material. The composite membrane contains at least one organic polymer membrane consisting of polymer film-forming materials with a thermal resistant temperature of 170 DEG C to 500 DEG C and heat shrinkage of 0% to 5%. Preferably, a plasticizer is added during solution preparation to achieve more uniform pore distribution so as to obtain the composite membrane with excellent performance. The diaphragm has high temperature resistance and high safety when used for battery diaphragm. In addition, the diaphragm has good solution adsorption performance, so that the diaphragm can adsorb the electrolyte to improve the circle performance of the battery. The invention also provides the diaphragm preparation method, which is simple and convenient. Compared with the conventional battery and the battery using PET composite diaphragm with inorganic coating, the battery using the diaphragm has higher capacity, better high-rate discharge characteristics and low-temperature discharger performance, no flame and liquid leakage during high-temperature test, and excellent high-temperature safety performance.
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Description

【Technical field】

[0001] The invention relates to a diaphragm, a preparation method thereof and a lithium ion battery. 【Background technique】

[0002] Separators are a key component of lithium-ion batteries. Separators for Li-ion batteries are usually thin porous insulating materials with high ion permeability, good mechanical strength, and long-term stability to various chemicals and chemical solvents. When a large current is generated inside the battery due to an external short circuit or wrong connection, and the internal temperature of the battery rises to the closed cell temperature of the diaphragm, the diaphragm will be thermally melted and the micropore structure will be closed, thereby cutting off the current and ensuring the safety of the battery. The performance of the separator determines the interface structure and internal resistance of the battery, which in turn affects the key characteristics of the battery such as capacity, cycle, charge and discharge curre...

Claims

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