AGM sealed lead-acid battery uses pure sulfuric acid aqueous solution as electrolyte, and its density is 1.29-1.3lg/cm3. Except for a part of the electrolyte absorbed inside the plate, most of it exists in the glass fiber membrane. In order to provide a channel for the oxygen precipitated from the positive electrode to the negative electrode, it is necessary to keep 10% of the pores of the separator that is not occupied by the electrolyte, that is, a lean liquid design. In order to make the electrode plate fully contact the electrolyte, the electrode group adopts the method of tight assembly.