Structure and method for supplementing lithium to lithium ion battery based on lithium silicide composite material

Abstract

According to a structure and method for supplementing lithium to a lithium ion battery based on a lithium silicide composite material, a lithium silicide pole piece is arranged at the bottom in a battery shell, and the lithium silicide pole piece is connected and conducted to a positive pole lug or a negative pole lug of a battery core through a nickel strap. In the first charging and discharging process, the lithium silicide composite material releases lithium ions into the electrolyte to make up the lithium ions corresponding to the irreversible capacity, so that the first coulombic efficiency of the battery is improved; in the subsequent charge-discharge cycle process, the lithium silicide composite material continuously releases lithium ions into the electrolyte, and a lithium battery system always keeps lithium with a certain reversible capacity, so that the battery capacity attenuation is reduced, the lithium ions can be continuously released to supplement lithium for the lithium battery, the lithium supplement is safer and more convenient, the requirements for process devices and environmental conditions are lower, the operation is simple, the safety is good, and the large-scale production is easy.

Description

technical field [0001] The invention belongs to the technical field of lithium ion battery manufacturing, and in particular relates to a structural lithium method for supplementing lithium to lithium ion batteries based on lithium silicide composite materials. Background technique [0002] Lithium-ion batteries have the characteristics of high energy density, long cycle life, high voltage, high power, and wide operating temperature range. These excellent characteristics make lithium-ion batteries widely used in the three major fields of consumer electronics, power batteries and energy storage. . In the first cycle of lithium-ion batteries, the SEI film formed on the surface of the graphite negative electrode has a first irreversible capacity loss of 5% to 15%, and the loss of high-capacity silicon-based materials is 15% to 35%. Lithium supplementation technology has been studied to improve the reversible cycle capacity of lithium-ion batteries, and active lithium compensati...

AI Technical Summary

Problems solved by technology

[0003] Existing lithium supplementation technology usually sticks a layer of lithium foil (<10um) on the surface of the negative electrode sheet, or sprays or evaporates a layer of lithium powder. Since metal lithium will react with moisture and nitrogen in the air, small particles of metal Lithium is more active, and there is a risk of combustion and explosion in the air environment, so it is difficult to realize large-scale industrial production of this scheme

Lithium metal is evenly coated on the negative electrode. Lithium dendrites are easy to form in the uneven coating of lithium metal during the subsequent battery cycle, and the contact area between lithium metal and the separator in the battery is large, and the growth of dendritic crystals pierces the separator and causes a short circuit in the battery. greater risk

[0004] Redesign the battery structure, add metal lithium as the third electrode in the lithium-ion battery, draw the third electrode from the metal lithium and form the negative electrode to discharge the electrode to the negative electrode to pre-replenish lithium, and then the battery is normalized, resulting in this Technical battery design is complex and the process is cumbersome

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