Lithium ion battery safety coating and application thereof as well as lithium ion battery

Abstract

The invention discloses a lithium ion battery safety coating. The lithium ion battery safety coating is prepared from a vinyl silane coupling agent, a binder and polyethylene microspheres through thefollowing steps: adding toluene and the vinyl silane coupling agent to the polyethylene microspheres, performing reflux reaction for 20-28 hours, filtering and drying to obtain polyethylene powder, and then mixing the polyethylene powder with the binder, sequentially stirring and dispersing to prepare a safety coating paste, and coating the safety coating paste to form a safety coating. The invention also discloses an application method of the lithium ion battery safety coating and a corresponding lithium ion battery. The safety coating disclosed by the invention has thermal blocking characteristics, can block the transmission of lithium ions in an electrolyte, ensures that side effects of heat production no longer occur, and improves the thermal stability of the battery; the safety coating has excellent organic solvent resistance characteristics and voltage resistance characteristics, and is applicable to the lithium ion battery; and the prepared lithium ion battery has the advantagesof high safety, no smoke, no fire, no combustion and the like.

Description

technical field [0001] The invention relates to the technical field of lithium ion battery manufacturing, in particular to a lithium ion battery safety coating, its application and the 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. 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 internal tempe...

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Problems solved by technology

[0004] For example, Chinese Patent Publication No. CN104269509A, the patent publication date is January 7, 2015, discloses a ceramic coating diaphragm for lithium batteries and a preparation method thereof, which includes a ceramic coating and a substrate diaphragm, and the ceramic coating is composed of a water-based ceramic coating The coating slurry is evenly coated on the surface of the substrate diaphragm, and the ceramic coating slurry includes 10-30wt% of alumina, 0.5-3wt% of adhesive, 0.2-1.0wt% of additives and 0.01-0.1wt% % additives, alumina is a nano-alumina powder with a particle size ratio D1 / D2 of 0.10 to 0.20; the ceramic coating diaphragm of the technical solution of the present invention has improved thermal safety and strong wettability to the electrolyte, and is applied in Lithium batteries can improve the cycle life of the battery; however, the ceramic-coated diaphragm can only improve the thermal stability of the diaphragm, and cannot block the heat-generating side reaction, so the improvement effect is limited. At present, it can only solve the problem that the energy density does not exceed 200Wh / kg. Battery safety issues, not widely available

Another example is the Chinese Patent Publication No. CN104409681A, the patent publication date is March 11, 2015, which discloses a preparation method of a lithium-ion battery pole piece containing a PTC coating, and the pole piece prepared by the method is a multilayer coated pole piece , before the current collector is coated with a slurry containing positive or negative active materials, a temperature-sensitive precoat is coated on the current collector in advance; the temperature-sensitive precoat has a composition comprising a binder, Positive temperature type material and conductive agent; the weight ratio of binder, positive temperature type material and conductive agent is (2~8):(1~8):(0~7); the PTC-containing compound prepared by the method provided by the invention Coated lithium-ion battery pole piece, the battery containing the pole piece has good safety characteristics such as overcharge, short circuit, extrusion, needle punching; but its PTC coating contains a variety of high molecular polymers, and its polymer system is not Mature, and the stability of these polymers in the battery environment is poor, especially in the organic electrolyte and in the wide electrochemical window. At the same time, this type of polymer PTC coating is processed in large quantities There is a certain degree of difficulty in processing and manufacturing

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