SEPARATOR, PREPARATION METHOD THEREFOR AND RELATED SECONDARY BATTERY, BATTERY MODULE, BATTERY PACK AND DEVICE

The present application relates to a separator in the electrochemical field and a preparation method therefor, and to a secondary battery comprising the separator, a device comprising the secondary battery. The separator of the present application is prepared by a simple process and has excellent heat resistance performance. Moreover, the secondary batteries and devices comprising the separator of the present application have good safety performance and cycling performance.