Positive plate and lithium ion battery

Abstract

The invention provides a positive plate and a lithium ion battery. The positive plate comprises a positive current collector and a positive diaphragm, wherein the positive diaphragm is arranged on thepositive current collector and comprises a first positive material layer and a second positive material layer, the first positive electrode material layer is arranged on the positive electrode current collector and comprises a first positive electrode active material, the first positive electrode active material is a ternary positive electrode material, the second positive electrode material layer is arranged on the first positive electrode material layer and comprises a second positive electrode active material, the second positive electrode active material is selected from one or more of olivine type lithium-containing phosphate and spinel type lithium manganate, the total reversible capacity of the first positive electrode active material per unit area of the positive electrode diaphragm is a, the total reversible capacity of the second positive electrode active material per unit area of the positive electrode diaphragm is b, and that a / b is not smaller than 1 and is not greater than 30 is satisfied. The positive plate is advantaged in that high-temperature cycle performance and safety performance of the lithium ion battery can be improved, and the lithium ion battery is ensured to have relatively high energy density.

Description

technical field [0001] The present application relates to the field of batteries, in particular to a positive electrode sheet and a lithium ion battery. Background technique [0002] The energy crisis and smog have led to an increasingly urgent demand and development of new energy vehicles. It is an inevitable trend for pure electric new energy vehicles to gradually replace traditional gasoline vehicles. However, new energy vehicles have increasingly high requirements for power batteries. more prominent. For example, high-quality new energy vehicles require lithium-ion batteries to have higher energy density, so as to ensure that new energy vehicles have a longer cruising range; high-quality new energy vehicles also require lithium-ion batteries to have better cycle performance, so that Ensure that new energy vehicles have a longer service life; high-quality new energy vehicles have more stringent requirements for safety performance, and need to avoid thermal runaway of lit...

AI Technical Summary

Problems solved by technology

At the same time, lithium iron phosphate will also reduce the working voltage of lithium-ion batteries, thus greatly reducing the energy density of lithium-ion batteries; the relatively high content of cobalt (Co) in low-nickel ternary cathode materials will increase the energy density of lithium-ion batteries. manufacturing cost

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