Battery

Abstract

The invention relates to a battery. The battery comprises a positive pole piece, a diaphragm and a negative pole piece, wherein the positive pole piece comprises a positive current collector and at least two positive active material layers coated on at least one surface of the positive current collector; the lower-layer positive active material layer in contact with the positive current collectorcomprises a first positive active material, a first polymer material and a first conductive material; based on the total weight of the lower-layer positive active material layer, the weight percentageof the first positive active material is A%, the weight percentage of the first polymer material is B%, and the weight percentage of the first conductive material is C%; the upper-layer positive active material layer which is in contact with the lower-layer positive active material layer and is away from the positive current collector comprises a second positive active material, a second polymermaterial and a second conductive material; based on the total weight of the upper-layer positive active material layer, the weight percentage of the second positive active material is A'%, the weightpercentage of the second polymer material is B'%, the weight percentage of the second conductive material is C'%, A% is less than A'%, B% is greater than B'%, C% is greater than or equal to C'%; and the first polymer material comprises an oily polymer material with the solubility in NMP at the temperature of 130 DEG C within 5min being 30% or less of the solubility of PVDF under the same conditions. The battery has good safety and improved electrical properties.

Description

technical field [0001] The invention belongs to the technical field of electrochemistry, and more specifically, the invention relates to a battery. 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 have largely limited the application and popularization of lithium-ion batteries. [0003] Although researchers have proposed many methods to improve the safety of batteries, there is still a lack of very effective means for the potential safety hazards caused by battery punctures. In view of this, it is indeed necessary to provide a battery that can improve battery s...

AI Technical Summary

Problems solved by technology

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 harm

Therefore, the safety problems of lithium-ion batteries have largely limited the

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