Negative current collector, negative pole piece and electrochemical device

Abstract

The invention discloses a negative current collector, a negative pole piece and an electrochemical device. The negative current collector comprises a support layer and a conductive layer arranged on at least one of two opposite surfaces in the thickness direction of the support layer, wherein the density of the support layer is smaller than that of the conductive layer; the thickness D1 of the conducting layer is larger than or equal to 300 nm and smaller than or equal to 2 micrometers, and preferably, D1 is larger than or equal to 500 nm and smaller than or equal to 1.5 micrometers. When thetensile strain of the negative current collector is 1.5%, the square resistance growth rate T of the conductive layer is less than or equal to 5%. The negative electrode current collector provided bythe invention can simultaneously consider low weight and good conductivity and current collection performance, so that the electrochemical device can simultaneously consider relatively high weight energy density and good comprehensive electrochemical performance.

Description

technical field [0001] The invention belongs to the technical field of electrochemical devices, and in particular relates to a negative electrode current collector, a negative electrode sheet and an electrochemical device. Background technique [0002] Due to the advantages of high energy density, high output power, long cycle life and low environmental pollution, lithium-ion secondary batteries are widely used in electric vehicles and consumer electronics products. With the continuous expansion of the application range of lithium-ion secondary batteries, people have put forward higher and higher requirements for the energy density of lithium-ion secondary batteries. The metal current collectors used in the prior art have relatively large thickness (usually 18 μm to 30 μm) and high density, resulting in low energy density of lithium-ion secondary batteries, which cannot meet the increasingly high requirements of the market. Therefore, how to improve the energy density of th...

AI Technical Summary

Problems solved by technology

The metal current collectors used in the prior art have relatively large thickness (usually 18 μm to 30 μm) and high density, resulting in low energy density of lithium-ion secondary batteries, which cannot meet the increasingly high requirements of the market

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