Method for preparing SEI-like film component additive as well as electrolyte solution, lithium-ion battery, battery module, battery pack and powered device

A method for preparing a battery comprising a negative electrode sheet and an electrolyte solution, the method comprising:

• reacting an organic solution of lithium naphthalenide with a mixed solvent in an inert gas atmosphere to obtain a mixture containing an SEI-like film component additive, wherein,
• a mass ratio of the lithium naphthalenide in the organic solution of lithium naphthalenide to the mixed solvent is 2-8:1, and the mixed solvent comprises ethylene carbonate, methyl ethyl carbonate, and dimethyl carbonate, a reaction temperature W1 of the organic solution of lithium naphthalenide with the mixed solvent is 45° C. to 60° C., and a reaction time S1 is 60 minutes to 180 minutes;
• drying the mixture in vacuum to obtain SEI-like film component additive as a solid, a temperature at which the mixture is dried under vacuum is 60° C. to 80° C.;
• dissolving the SEI-like film component additive in a non-aqueous solvent to form an electrolyte solution,
• adding a lithium-supplying material to the electrolyte solution, wherein the lithium-supplying material comprises at least one of lithium hexafluorophosphate, lithium difluorophosphate, and lithium tetrafluoroborate, a mass ratio of the SEI-like film component additive to the lithium-supplying material is 0.5-5:100,
• adding an additive in a mass of 0.5%-3% of a total mass of the electrolyte solution, the additive is selected from one or more of fluoroethylene carbonate, vinylene carbonate, vinyl ethylene carbonate, and ethylene sulfate, wherein the SEI-like film component additive is 0.1% to 0.3%, based on a total weight of the electrolyte solution,
• preparing a negative electrode sheet, wherein the negative electrode sheet comprises a negative electrode film layer, the negative electrode film layer comprises a negative electrode active material, and the negative electrode active material comprises one or more of natural graphite, artificial graphite, mesocarbon microbead, hard carbon, soft carbon, silicon-carbon composite, lithium-tin alloy and lithium-aluminum alloy,
• wherein a mass percentage content of the SEI-like film component additive in the electrolyte solution is m1, a mass of the negative electrode active material on a single-sided negative electrode current collector is m2 with a unit of g/77 mm2, a ratio of m1 to m2 is 1.1-2.8 (g/77 mm2)−1.