Positive pole piece and electrochemical device

Abstract

The invention relates to the field of batteries, in particular to a positive pole piece and an electrochemical device. The positive pole piece comprises a current collector and an electrode active material layer arranged on at least one surface of the current collector, wherein the current collector comprises a support layer and a conductive layer arranged on at least one surface of the support layer, the thickness D2 of a single surface of the conductive layer is more than or equal to 30nm and less than or equal to 3mu m, the thickness D1 of the support layer is more than or equal to 1mu m and less than or equal to 30mu m, and the support layer is made of a high polymer material or a high polymer composite material; the electrode active material layer includes an electrode active material, a binder, and a conductive agent, and the electrode active material includes a small-particle active material having an average particle diameter D50 of 1.0 [mu] m to 7.0 [mu] m and a large-particleactive material having an average particle diameter D50 of 7.1 [mu] m to 20.0 [mu] m. The electrochemical device comprising the positive pole piece has high energy density, good safety performance (especially nail penetrating safety performance) and electrochemical performance.

Description

technical field [0001] The present application relates to the field of batteries, in particular, to a positive electrode sheet and an electrochemical device. Background technique [0002] Lithium-ion batteries are widely used in electric vehicles and consumer electronics due to their advantages such as high energy density, high output power, long cycle life and low environmental pollution. With the continuous expansion of the application range of lithium-ion batteries, the requirements for the gravimetric energy density and volumetric energy density of lithium-ion batteries are also getting higher and higher. [0003] In order to obtain lithium-ion batteries with high mass energy density and volume energy density, lithium-ion batteries are usually improved as follows: (1) select positive electrode materials or negative electrode materials with high discharge specific capacity; (2) optimize the mechanical design of lithium-ion batteries , to minimize its volume; (3) select a...

AI Technical Summary

Problems solved by technology

[0005] For pole pieces and batteries using metal-coated plastic current collectors, although the energy density is improved, it may cause some performance degradation in terms of processability and electrochemical performance.

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