Negative modified high-safety lithium-ion battery

Abstract

The invention relates to a cathode modified high security lithium ion battery, which is characterized in that a negative plate contains a thermal protective agent. When the battery is heated to a certain temperature, the thermal protective agent conducts crosslinking reaction to barrier thermal runaway; the thermal protective agent bismaleimide A shown in formula (I), or bismaleimide B shown in formula (II), or a bismaleimide oligomer C shown in formula (III), or bismaleimide oligomer D shown in formula (IV). The thermal protective agent can accept a variety of modifications, including alkoxy modification and acyl modification, has a large amount of varieties and is convenient for selection and usage. When being heated to a certain temperature, the thermal protective agent conducts crosslinking reaction, thus preventing thermal runaway. The battery has strengthened safety performance, and the manufacturing method is also simple.

Description

technical field [0001] The invention relates to a negative electrode modified high-safety lithium-ion battery, and in particular to a high-safety secondary lithium-ion battery with a thermal actuation safety mechanism, which belongs to the secondary lithium-ion battery. Background technique [0002] Lithium-ion batteries have been widely used in 3C products such as computers, communications and consumer electronics, and are also being used in the fields of electric vehicles and large-scale energy storage. However, due to the high-voltage resistant organic electrolyte solvent used in lithium-ion battery systems It has strong flammability, and the positive / negative active material with high capacity will decompose and release a lot of heat when the temperature rises, so that the heat generated by the lithium battery may ignite the organic solvent when it is used improperly. danger, even fire and explosion; in addition, during the charging and discharging process of lithium-ion...

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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