Method for evaluating mechanical performance of lithium battery foil

Abstract

The invention relates to the technical field of batteries, and discloses a method for evaluating the mechanical property of a lithium battery foil, which comprises the following steps: providing a battery cell group comprising a plurality of battery cells, a pole piece of each battery cell comprises a to-be-evaluated foil and an active material coating layer coated on the surface of the to-be-evaluated foil, and the outer surface of the active material coating layer is also coated with a thermal expansion material coating layer; the battery cell group is baked within a preset temperature range, and the baking temperatures of the battery cells are different, so that the thermal expansion material coating layers of the battery cells are expanded to different states; and obtaining the pole piece state of each battery cell, and evaluating the mechanical property of the to-be-evaluated foil according to the pole piece state. According to the embodiment of the invention, not only is the actual use scene of the foil simulated, so that the actual test requirement can be met, but also the baking process is adopted to replace the conventional charging and discharging process, the pole piece state under different expansion rates can be obtained in a short time, the evaluation period is greatly shortened, and the occupation of test resources is reduced.

Description

technical field [0001] The invention relates to the technical field of batteries, in particular to a method for evaluating the mechanical properties of a lithium battery foil. Background technique [0002] At present, a tensile machine is usually used to uniaxially stretch a foil of a specific size in the longitudinal or transverse direction, and the tensile strength and elongation of the foil in the longitudinal or transverse direction are measured to evaluate the mechanical properties of the foil. [0003] In fact, during the actual use of lithium battery foils, physical failure (cracking or even breaking) usually occurs during the charging and discharging process of lithium batteries. This is because, with the cyclic charge and discharge of the battery, the positive and negative electrode sheets made of foil will expand and shrink in volume, especially in the high nickel / silicon system, the volume of the battery will expand significantly, and the foil will be affected by ...

AI Technical Summary

Problems solved by technology

[0006] The purpose of the present invention is to provide a method for evaluating the mechanical properties of lithium battery foils, so as to overcome the defects of long test period and taking up more test resources in the prior art

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