The invention discloses a method for testing the pore closing temperature of a diaphragm. The method comprises the following steps: preparing a first standard diaphragm, a second standard diaphragm, athird standard diaphragm, standard green
adhesive tapes, a standard
copper foil and a standard aluminum-
plastic film, wherein the middle of the standard green plastic
adhesive is provided with a circular hole with a preset
diameter; respectively pasting one to five
layers of the first standard diaphragm to one of the standard green
adhesive tapes to obtain a first target diaphragm; respectively pasting one to five second standard diaphragms to one of the standard green adhesive tapes to obtain a second target diaphragm; respectively pasting one to five
layers of the third standard diaphragm to one of the standard green adhesive tapes to obtain a third target diaphragm; sequentially assembling the first target diaphragm, the second target diaphragm, the third target diaphragm, the standardcopper foil, the standard aluminum-
plastic film and a preset battery to obtain a corresponding flexibly packed battery; and measuring impedance of the flexibly packed battery by adopting an electrochemical
workstation, linearly fitting the ohmic impedance value and the diaphragm layer number, and calculating the
ion conductivity of the diaphragm to obtain the catastrophe point of the
ion conductivity of the diaphragm, that is the corresponding pore closing temperature of the diaphragm.