Battery monomer, battery module and vehicle

The utility model discloses a single battery, a battery module and a vehicle, the single battery comprises a shell, cover plates are arranged on two opposite sides of the shell in a first direction, and each cover plate is provided with a pole; the pole core is arranged in the shell, the pole core comprises a positive pole piece, a negative pole piece and a diaphragm, the diaphragm is arranged between the positive pole piece and the negative pole piece, the positive pole piece is electrically connected with one pole column through a positive pole lug, and the negative pole piece is electrically connected with the other pole column through a negative pole lug; the inner sides of the two cover plates are provided with supporting parts which abut against the diaphragm, in the first direction, the length of the diaphragm is L diaphragm, the minimum distance between the supporting parts on the two sides of the pole core is L spacing, and the battery monomer meets the following condition: L diaphragm-6 < L spacing