An electrolyte additive of a high-pressure solid lithium iron phosphate battery and an electrolyte containing the additive

Abstract

The invention discloses an electrolyte additive of a high-pressure solid lithium iron phosphate battery and an electrolyte containing the additive, wherein the electrolyte additive comprises organic phosphorus esters with the following general formula: C9H19C6H4O (CH2CH2O) n; C9H19C6H4O (CH2CH2O) n; PO(OH)2, n=3-12; the electrolyte additive also comprises at least one kind of Vinylene carbonate, vinyl fluorocarbonate or 1, 3-propanesulfonic acid lactone and ethyl sulfite; The additive and that electrolyte, non-aqueous organic solvents form the electrolyte with the appropriate ratio, The electrolyte additive has the following advantages: By adding wetting additive, the surface tension of the electrolyte can be reduced, the wettability and permeability of the electrolyte to the electrode sheet and the membrane can be improved, the wetting time can be shortened, the production cost can be saved, the wetting effect can be improved, the interface impedance of the battery can be reduced, theutilization efficiency of the living matter can be improved, the battery capacity can be improved, and the discharge rate characteristic can be improved. Moreover, the impregnation additive has the advantages of high heat resistance stability, high chemical stability and low combustibility, and can improve the stability of electrolyte.

Description

technical field [0001] The invention relates to the field of electrolytes for lithium ion batteries, in particular to an electrolyte additive for a high-pressure compacted lithium iron phosphate battery and an electrolyte containing the additive. Background technique [0002] With the aggravation of the energy shortage situation and the improvement of human environmental awareness, in order to eradicate the impact of automobile exhaust on the environment, the research and development of electric vehicles has become a problem of concern to the world. At present, the two major technical routes that occupy the main market share in China-lithium iron phosphate battery and ternary battery have already occupied a dominant position in the fields of pure electric buses, pure electric passenger vehicles and special vehicles respectively. Among them, there is a large gap between lithium iron phosphate batteries and ternary batteries in terms of energy density, which directly puts grea...

AI Technical Summary

Problems solved by technology

When disassembling and analyzing lithium batteries, we will find that batteries with poor cycle performance are often related to the poor infiltration effect of the electrolyte on the pole pieces.

When the infiltration effect of the electrolyte is not good, the ion transmission path becomes farther, which hinders the shuttle between the positive and negative electrodes of lithium ions, and the electrode pieces not in contact with the electrolyte cannot participate in the electrochemical reaction of the battery. At the same time, the interface resistance of the battery increases, which affects the lithium ion. Battery rate performance, discharge capacity and service life

[0005] The traditional battery electrolyte generally uses a solvent combination of cyclic carbonate and chain carbonate. The viscosity of the electrolyte is relatively high, and the pole pieces are made of inorganic ceramic materials. The ability to absorb organic electrolyte is limited and time-consuming, which easily affects the normal performance of the battery capacity. and reduce battery cycle life

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