The invention discloses a cell and an electrolyte injection method. The cell comprises a cell rolling core, a shell wrapped outside the cell rolling core, an end cover covering the upper part of the shell, a safety valve hole and an electrolyte injection hole, wherein the safety valve hole is arranged on the end cover, and the electrolyte injection hole is arranged at the lower part of the shell. In the cell, the safety valve hole is arranged on the end cover of the cell, and the electrolyte injection hole is arranged at the lower part of the shell of the cell. When the electrolyte is injected into the cell, the vacuumization is carried out from the safety valve hole, and the electrolyte is injected from the electrolyte injection hole at the bottom of the cell. The electrolyte injection efficiency of the cell is improved obviously, and because the electrolyte injection way that the electrolyte is injected from the bottom of the cell and the vacuumization is carried out at the upper part of the cell is adopted, air bubbles inside the cell are reduced. The infiltration effect of the cell rolling core is good, thus the cell capacity is greatly increased. By using the electrolyte injection method, the electrolyte injection time is shortened effectively, the working efficiency is improved, the infiltration of the cell rolling core is more thorough, the air bubbles between pole pieces can be discharged, and the cell capacity is increased.