Lithium ion battery

Abstract

The embodiment of the invention provides a lithium ion battery, the lithium ion battery comprises a positive plate and a negative plate, the positive electrode active material of the positive plate comprises lithium manganese iron phosphate and a ternary material, the negative electrode active material of the negative plate is graphite, and the lithium ion battery satisfies the following formula: 1.08 < = (M3 * eta 3 * y)/[(M1 * eta 1 * A1 + M2 * eta 2 * A2) * x] < = 1.12 (1) 0.49 < = [M1 * (1-eta 1) * A1 + M2 * (1-eta 2) * A2] * x/[M3 * (1-eta 3) * y] < = 1.15 (2), m1 is the first charging specific capacity of the lithium iron manganese phosphate, eta 1 is the first efficiency of the lithium iron manganese phosphate, A1 is the mass percent of the lithium iron manganese phosphate in the positive electrode active material, M2 is the first charging specific capacity of the ternary material, eta 2 is the first efficiency of the ternary material, A2 is the mass percent of the ternary material in the positive electrode active material, and the sum of the mass percent of the lithium iron manganese phosphate and the mass percent of the ternary material is 100%. M3 is the first specific discharge capacity of the graphite, and eta 3 is the first efficiency of the graphite. According to the lithium ion battery provided by the embodiment of the invention, the energy density and the cycle performance of the lithium ion battery are improved on the basis of ensuring high safety of the lithium ion battery.

Description

technical field [0001] The present application relates to the technical field of power equipment, and in particular, the present application relates to a lithium ion battery. Background technique [0002] With the gradual strengthening of energy and environmental awareness, new energy vehicles have made great progress in recent years. Among them, electric vehicles are one of the main directions. In the power battery of electric vehicles, lithium-ion batteries occupy a very important position. As an important part of lithium-ion batteries, the selection of positive electrode materials directly affects the performance of lithium-ion batteries. Lithium manganese iron phosphate (LMFP for short) cathode material has become the mainstream cathode material for lithium-ion batteries due to its high structural stability, good cycle performance and safety performance. [0003] Lithium manganese iron phosphate has high theoretical specific capacity and first-time efficiency, which ca...

AI Technical Summary

Problems solved by technology

[0004] The embodiment of the present application provides a lithium-ion battery to solve the problem that the capacity of lithium manganese iron phosphate in the specific capacity of traditional lithium-ion batteries is difficult to effectively exert

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