Provided are an insulation patch, a battery cell, a battery, and a device. An electrode assembly is coated with the insulation patch, and a side edge of the insulation patch has a hot-melt region and a non-hot-melt region. The hot-melt region is configured to hot melt with a lower plastic, and the non-hot-melt region is lower than the hot-melt region. After the electrode assembly coated with the insulation patch is mounted to a shell, and the hot-melt region of the insulation patch is hot melted to the lower plastic of a top cover assembly, when a top cover member and the shell are welded together by using a laser, the non-hot-melt region of the insulation patch is lower than the hot-melt region, preventing the non-hot-melt region of the insulation patch from interfering with a welding position between the top cover member and the shell.