End cap assembly, battery cell, battery, and device using battery

The embodiment of the invention provides an end cover assembly, a battery monomer, a battery and a device, relates to the field of batteries, and aims to improve the performance of the battery monomer. The end cover assembly comprises a cover plate, a first insulating component, an electrode terminal, an adsorption piece and a sealing piece. The cover plate is provided with a mounting through hole, and the mounting through hole penetrates through the cover plate in the axial direction of the mounting through hole; a diversion channel is arranged between the first insulating component and the cover plate; the flow guide channel is in fluid communication with the mounting through hole; an electrode terminal mounted in the mounting through hole; the adsorption piece is placed in the flow guide channel; the sealing piece is used for sealing the mounting through hole. According to the technical scheme, the electrolyte entering along the gap between the cover plate and the first insulating component in the manufact