BATTERY CELL, BATTERY, AND METHOD AND APPARATUS FOR PREPARING BATTERY CELL

Embodiments of the present disclosure provides a battery cell, a battery, an electrical device and a device for preparing a battery cell. The battery cell includes a housing being hollow and including an opening, and an end cover assembly includes an end cover and an insulator. The end cover is configured to be connected to the opening of the housing and at least the part of the end cover is inserted into the housing. A part of the end cover inserted into the housing includes an end surface and a first side surface. The end surface is substantially perpendicular to an insertion direction of the end cover. The first side surface is distributed along a periphery of the end surface and is opposite to an inner wall surface of the housing. The inner wall surface is substantially parallel to the insertion direction of the end cover, and the end surface and the first side surface intersect to form a first edge. The insulator is connected to the end surface, and the insulator extends beyond the first edge toward the inner wall surface in a first direction. Technical solutions of embodiments of the present disclosure can enhance safety of a battery cell.