Positive pole piece and electrochemical device

Abstract

The invention relates to a positive pole piece and an electrochemical device. The positive pole piece comprises a current collector, a positive active material layer and a safety coating arranged between the current collector and the positive active material layer, wherein the safety coating comprises a polymer matrix, a conductive material and an inorganic filler, the polymer matrix is polyvinylidene fluoride and / or polyvinylidene chloride, and the weight ratio of the polymer matrix to the conductive material is greater than or equal to 2. The positive pole piece can improve the nail penetration safety performance of an electrochemical device (such as a capacitor, a primary battery or a secondary battery).

Description

technical field [0001] The invention belongs to the technical field of electrochemistry, and more specifically, the invention relates to a positive pole piece and an electrochemical device comprising the positive pole piece. 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. However, when lithium-ion batteries are subjected to abnormal conditions such as extrusion, collision or puncture, they are prone to fire and explosion, causing serious hazards. Therefore, the safety problems of lithium-ion batteries limit the application and popularization of lithium-ion batteries to a great extent. [0003] A large number of experimental results show that the short circuit in the battery is the root cause of the safety hazard of lithium-ion batteries. In order to avoid the short circuit in the battery, ...

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Problems solved by technology

However, in this improved manner, when the active material slurry is coated on the surface of the PTC material layer, the solvent in the slurry (such as NMP, etc.) will dissolve the PTC material in the PTC layer and enter the upper active material layer, not only Make the PTC layer lose the PTC effect, and it will deteriorate the electrical performance

In addition, during the compaction step in the pole piece manufacturing process, the PTC material layer is easily squeezed to the edge, resulting in direct contact between the electrode active material layer and the current collector, thereby losing the effect of improving safety performance.

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