The embodiments of the application provides an end cover assembly, a battery cell, a battery module and a device, the end cover assembly is used for the battery cell, the end cover assembly includes an end cover; an electrode terminal disposed on the end cover; an insulating member for insulating the electrode terminal and the end cover and disposed to surround the electrode terminal; wherein the insulating member abuts the electrode terminal, at least one of the insulating member and the electrode terminal is provided with a stress relief groove, the stress relief groove is configured to absorb stress generated by the electrode terminal's abutting the insulating member.