Method for detecting thermal stability of battery separator

The needling experiment is an important test for evaluating the safety performance of a lithium-ion battery, performance such as the pore closing temperature, the breaking temperature, the thermal stability and the like of a separator are particularly critical and related to probability of avoidance of thermal runaway of the lithium-ion battery. However, few testing methods for the thermal stability of the separator exist at present, and the most common method is placing the separator in a constant-temperature oven at a certain temperature for baking for a certain period and measuring the change of the size of the separator. However, the testing method cannot accurately reflect the thermal stability of the lithium-ion battery during needling, so that the invention adopts a method for simulating the lithium-ion battery during needling and measuring the change of the separator.