a battery

Abstract

The invention relates to a battery, comprising a positive electrode sheet, a separator and a negative electrode sheet, wherein the positive electrode sheet comprises a positive electrode current collector and at least two layers of positive electrode active material layers coated on at least one surface of the positive electrode current collector, and the positive electrode current collector is connected with the positive electrode current collector. The lower positive electrode active material layer in fluid contact comprises a first positive electrode active material, a first polymer material and a first conductive material, and based on the total weight of the lower positive electrode active material layer, the weight percentage of the first positive electrode 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%. material, the second polymer material and the second conductive material, based on the total weight of the upper positive electrode active material layer, the weight percentage of the second positive electrode active material is A'%, and the weight percentage of the second polymer material is B '%, the weight percentage of the second conductive material is C'%, of which A% <a′％，b％>B'%, C%≥C'%, and the first polymer material includes an oily polymer material whose solubility in NMP at 130°C within 5 minutes is less than 30% of that of PVDF under the same conditions. The battery has good safety and improved electrical properties.< / a′％，b％>

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 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.

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