Positive modified high-safety lithium-ion battery

Abstract

The invention relates to a positive electrode modified high-safety lithium ion battery which is characterized in that a positive electrode plate contains a heat dynamic protective agent; when the battery is heated to a certain temperature, the heat dynamic protective agent is subjected to cross-linking reaction to block heat runaway; the heat dynamic protective agent is bismaleimide A described as the formula (I), or bismaleimide B having the structure described in the formula (II), a bismaleimide low polymer C described in the formula (III), or a bismaleimideformula low polymer D described in the formula (IV), and can be subjected to various of modifying; the various of modifying comprises alternative alkoxy modifying, acyl modifying and the like, and the variety range is wide, so that the alternative use is achieved; the safety performance of the battery is enhanced, and a preparation method is relatively simple.

Description

Technical field [0001] The invention relates to a positive electrode modified high-safety lithium ion battery, in particular to a high-safety secondary lithium ion battery with a thermal actuation safety mechanism. Background technique [0002] Lithium-ion batteries have been widely used in 3C products such as computers, communications and consumer electronics, and their applications in electric vehicles and large-scale energy storage are also being popularized. However, due to the high-voltage organic electrolyte solvent used in the lithium-ion battery system It has strong flammability, and the high-capacity positive / negative active material will release a large amount of heat when the temperature rises, so that the heat generated by the improper use of lithium batteries may ignite organic solvents. Dangerous, even fire and explosion; in addition, during the charge and discharge process of lithium ion batteries, due to the disintegration or phase change of the positive electrode...

AI Technical Summary

Problems solved by technology

[0003] In the known literature and patents, most of the positive electrode materials of lithium batteries are surface modified to improve safety, such as using metal oxides or metal fluorides to coat LiMO 2 (M stands for transition metal) surface, this method can improve the structural stability of the material, reduce the heat release between the material and the electrolyte, and achieve the purpose of safety improvement. However, the protection formed by introducing metal oxide or metal fluoride on the surface of the electrode material The film itself does not have a thermal actuation safety mechanism, and it cannot effectively inhibit the deoxidation phenomenon. Its internal short circuit caused by external environmental factors, such as accidental puncture or external impact damage, causes instantaneous high heat and causes the risk of battery explosion. not effectively reduced

[0004] Patent CN 101807724 provides a lithium battery with thermodynamic protection, which uses bismaleimide oligomer as a thermal protection agent to improve the safety of the battery, but obviously, the bismaleimide Amine oligomers have the problem of low solubility and inconvenient application

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