The invention primarily relates to a cell (1) for storing power, which is to be integrated in an electrical module for assembling a power storage system, having a first surface (1a; 1c) and a second surface (1b; 1d), characterised in that the cell (1) comprises at least one male element (5; 5a, 5b, 5c) on one of the first (1a; 1c) and second (1b; 1d) surfaces thereof, and at least one female element (6; 6a, 6b, 6c) on the other of the first (1a; 1c) and second (1b; 1d) surfaces thereof, which elements are shaped such as to be fitted into one another such that the cell (1) is configured such as to be assembled to another cell (1) of the same type, in that at least one male element (5; 5a, 5b, 5c) comprises at least one electrical connection interface having positive polarity (8; 8a, 8b, 8c) and in that at least one female element (6; 6a, 6b, 6c) comprises at least one electrical connection interface having negative polarity (9; 9a, 9b), or conversely such that the cell (1) is configured such as to be electrically connected to another cell (1) of the same type.