Method for evaluating mechanical performance of lithium battery foil

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