The invention relates to a method used for detecting residual capacities of energy storage cells, relates to the cell management technology field and solves a problem that a residual cell capacity measurement method in the prior art is not applicable to on-line cell measurement. According to the method, a solid electrolyte film generation process of an energy storage cell is analyzed, corresponding relations between capacity loss amount of the energy storage cell caused during generation of the solid electrolyte film and internal resistance increase amount of the energy storage cell are established, an off-line test method is adopted to obtain the capacity loss amount of the energy storage cell and the ohm internal resistance increase amount at different aging stages, the least square method is adopted to calculate fitting coefficients alpha 1 and alpha 2, a cell ohm internal resistance on-line identification method is further adopted to calculate and obtain the ohm internal resistance increase amount of the energy storage cell at different aging stages, the acquired known quantities are respectively substituted into the relation, through the relation Q=Q0-deltaQloss, the residual capacity Q of the energy storage cell can be obtained. The method is further applicable to residual capacity detection on other cells.