A battery unit includes: an electrode assembly, including a main body portion, and a negative tab and a positive tab, which respectively extend out from both ends of the main body portion along the length direction; a negative terminal and a positive terminal, arranged at the top of the electrode assembly; a first current collector for electrically connecting the negative tab with the negative terminal; and a second current collector for electrically connecting the positive tab with the positive terminal. The first current collector includes a first guiding plate. The first guiding plate is of a flat plate structure, and the negative tab is bent to one side of the first guiding plate away from the main body portion and is connected with the first guiding plate.