High energy density silicon-carbon battery non-expanding at high temperature

Abstract

The present invention relates to the technical field of batteries, and discloses a high energy density silicon carbon battery non-expanding at a high temperature, wherein the electrolyte solvent comprises 20-30% of EC, 55-65% of EMC, 5-15% of DMC, and 3-5% of FEC, the additives comprise methylene methanedisulfonate, tris(trimethyl)silane borate and vinylene carbonate, and the silicon-carbon battery formation process comprises: respectively charging for 28-32 min at 0.01C, 0.02C and 0.05C; standing for 4-6 h after charging at 0.1 C to achieve a voltage of 3.37 V, and evacuating to removing gas;charging at 0.1C to achieve a voltage of 4.3 V, placing for three days, and carrying out first capacity sorting, wherein 0.1C discharging is firstly performed and then 0.5C charging-discharging capacity calibration is performed twice in the first capacity sorting, and charging is performed at 4.3 V to achieve a full state; and after the first capacity sorting, aging the battery, evacuating, standing at a room temperature, and carrying out second capacity sorting through 0.5C charging-discharging. According to the present invention, the silicon-carbon battery can be prevented from gas generation expanding at the high temperature.

Description

technical field [0001] The invention relates to the technical field of batteries, in particular to a high-energy-density silicon-carbon battery that does not expand at high temperatures. Background technique [0002] As the preferred anode material for the next generation of high-energy density batteries, silicon-carbon anode materials have a higher theoretical capacity than graphite. At the same time, compared with pure silicon anodes, silicon-carbon anodes have small volume expansion, are not easy to pulverize, and have better cycle performance. . At present, silicon carbon anode has been used in power batteries as the anode material of high energy density cells. The performance of silicon-carbon batteries is relatively stable at room temperature. At present, the problems of volume expansion and flatulence at room temperature can be solved by using a suitable electrolyte. However, in a high-temperature environment, silicon-carbon batteries are prone to gas production, re...

AI Technical Summary

Problems solved by technology

However, in a high-temperature environment, silicon-carbon batteries are prone to gas production, resulting in increased battery volume and battery expansion, which seriously affects the cycle and storage performance of batteries at high temperatures, limiting the large-scale use of silicon-carbon batteries in large power batteries. application

[0003] At present, the conventional method is still to optimize the electrolyte additives alone, focusing on the negative film-forming additives to form a dense and stable SEI film to improve the problem of high-temperature gas production. Adding a certain amount of gas-production inhibitors to the electrolyte can from To a certain extent, the high-temperature performance of the battery is improved, but adding too many additives makes the SEI of the battery too thick and the impedance increases, which not only cannot completely solve the high-temperature gas production of the battery, but also affects the capacity and service life of the battery. Increase the cost of using the battery to a certain extent

Images