High-safety electrolyte for lithium ion battery and lithium ion battery

Abstract

The invention relates to the technical field of lithium ion battery manufacturing, and discloses a high-safety electrolyte for a lithium ion battery. The electrolyte is composed of the raw materials of organic solvent, lithium salt, a heat blocking additive, positive pole film former, negative pole film former and the like, wherein the organic solvent is carbonate; the lithium salt is lithium hexafluorophosphate; the positive pole film forming additive is a mixture of tri(hexafluoroisopropyl)phosphate and a nitrile additive; and the negative pole film forming additive is 1,3-propenyl-sultone.The high-pressure electrolyte provided by the invention has favorable oxidation resistance, high temperature resistance and safety properties; a high energy density battery using the electrolyte has favorable cycle and safety performance at high pressure and high temperature; and meanwhile, the hot blocking additive is further added in the electrolyte, so that the safety performance of the electrolyte is improved, and the assembled lithium ion battery can automatically stop exothermic reaction at high temperature, thereby ensuring the normal use and use safety of the lithium ion battery.

Description

technical field [0001] The invention relates to the technical field of lithium-ion battery manufacturing, in particular to an electrolyte solution for a high-safety lithium-ion battery and a lithium-ion battery. Background technique [0002] In recent years, the rapid development of portable electronic products, electric vehicles, energy storage power stations and other fields has put forward higher requirements for energy storage technology. Lithium-ion batteries are the first choice in these fields due to their high energy density, and their energy density is getting higher. As the energy density of lithium-ion batteries is getting higher and higher, the safety problems it faces are becoming more and more severe, which has severely limited the terminal use of high-energy-density lithium-ion batteries. [0003] The safety problem of lithium-ion batteries is mainly due to the thermal runaway of batteries. Due to the abnormal heat generation reaction inside the battery, the...

AI Technical Summary

Problems solved by technology

[0005] For method 1, since the ceramic-coated diaphragm can only improve the thermal stability of the diaphragm, it cannot block the side reaction of heat generation, so its improvement effect is limited

For method 2, although the thermal runaway reaction of the battery can be partially curbed, since the electrodes of lithium-ion batteries are usually porous electrodes, the electrolyte is filled in the abundant electrode gaps; the lithium ion conduction between the positive and negative electrodes is blocked, but The reaction between the active material inside the electrode and the electrolyte is still going on, which will further lead to heat accumulation and trigger a thermal runaway reaction

The disadvantage of the above two treatment methods is that they both treat the lithium-ion battery separator or use new materials, but they cannot completely contain the occurrence and continuous deterioration of the heat-generating reaction inside the lithium-ion battery from the source, and may even aggravate this production. Thermal reactions that make lithium-ion batteries more prone to spontaneous combustion or explosion over a period of time