High-energy-density lithium ion battery

Abstract

The invention discloses a high-energy-density lithium ion battery. The high-energy-density lithium ion battery comprises a positive electrode, a negative electrode, a diaphragm, an electrolyte and a packaging film, wherein the positive electrode active substance is LiNi0. 5Mn1. 5O2 and LiCoPO4, the negative electrode active substance is a mixed material of silicon monoxide, carbon-coated silicon and silicon carbon, the electrolyte is a high-voltage-resistant electrolyte, the diaphragm is a PE ceramic / PVDF composite diaphragm, and the packaging film is an aluminum-plastic film. According to theinvention, high-voltage LiNi<0.5>Mn<1.5>O<2> and LiCoPO<4> are used as positive electrode materials, and electrolyte with the resistance to a high voltage is matched; the high-capacity silicon-carbonmaterial is adopted as the negative electrode material, the volume expansion effect of the silicon-carbon negative electrode material in the cycle process of the battery is improved through the elastic adhesive, the energy density of the lithium ion battery can be effectively improved through the synergistic effect of the silicon-carbon negative electrode material and the high-voltage-resistant electrolyte, and the cycle performance of the battery is improved.

Description

technical field [0001] The invention belongs to the technical field of lithium ion batteries, and in particular relates to a lithium ion battery with high energy density. Background technique [0002] As we all know, lithium-ion batteries have attracted widespread attention due to their high energy density, high specific power, high operating voltage, good cycle performance, no memory effect, and no pollution. However, with the development of new energy vehicles, people have higher requirements on the performance of lithium-ion batteries, especially the energy density of lithium-ion batteries, which is an urgent problem to be solved. According to the "Made in China 2025" power battery development plan: in 2020, the battery energy density will reach 300Wh / kg; in 2025, the battery energy density will reach 400Wh / kg; in 2030, the battery energy density will reach 500Wh / kg. At present, the energy density of lithium-ion batteries is lower than 300Wh / kg, and further improvement i...

AI Technical Summary

Problems solved by technology

This periodic volume change will destroy the structure of the silicon material, and even lead to the pulverization of the silicon-based material, resulting in a large irreversible capacity loss and poor cycle performance of the silicon-based negative electrode, which limits its use as a lithium-ion battery. Application of negative electrode materials