Positive electrode sheet capable of discharging at high rate, and lithium ion battery comprising positive electrode sheet

Abstract

The invention provides a positive electrode sheet capable of realizing high-rate discharge, and a lithium ion battery comprising the positive electrode sheet. According to the invention, a first positive electrode active material layer is prepared from a first positive electrode active material comprising a polycrystalline nickel-containing ternary material, and a second positive electrode activematerial layer is prepared from a second positive electrode active material comprising a monocrystalline or monocrystalline-like nickel-containing ternary material; by arranging the first positive electrode active material layer and the second positive electrode active material layer, the coating amount can be reduced, and the rate capability of a lithium ion battery can be improved, or the energydensity of the lithium ion battery can be increased while the rate capability of the lithium ion battery is ensured; and by utilizing the characteristics of good stability of the second positive electrode active substance and relatively small contact area with an electrolytic solution, the side reaction in the high-rate discharge process can be reduced, the risk of gas production failure is reduced, and the quick discharge performance of the system can also be ensured.

Description

technical field [0001] The invention belongs to the technical field of lithium ion batteries, and in particular relates to a positive electrode sheet capable of high-rate discharge and a lithium ion battery including the positive electrode sheet. Background technique [0002] With the expansion of the demand for lithium-ion batteries in the consumer market, lithium-ion batteries are required to have higher power density and discharge rate, but the increase in discharge rate will inevitably increase the temperature rise of lithium-ion batteries during discharge, and in order to ensure electrolysis The liquid has a sufficiently high ionic conductivity, and lithium-ion batteries with high-rate discharge mostly use low-viscosity solvents, and low-viscosity solvents have relatively lower boiling points. [0003] At the same time, the positive plate in the lithium-ion battery with high rate discharge is also designed with low compaction and high residual liquid to ensure sufficien...

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Problems solved by technology

[0004] But this brings a serious problem: the temperature of the battery core body is high during high-rate discharge, causing the low-boiling point solvent to decompose to produce gas, and the contact area between the ternary material with high specific surface area and the electrolyte is large, and side reactions are more likely to occur. Leading to the failure of the battery core will also bring safety hazards

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