Differential power compensation type battery isothermal calorimeter and dynamic characteristic correction method

A dynamic characteristic correction method for a differential power compensation type battery isothermal calorimeter, comprising following steps:

• step 1, determining a model of a battery to be tested, and selecting a reference battery with a same model and a same size as the battery to be tested;
• step 2, according to the size of the battery to be tested, selecting appropriate flexible heating sheets, heat uniforming blocks and thermal conductive silica gel pads, and installing a sample side and a reference side in a heat sink of an isothermal calorimetric chamber respectively;
• wherein the sample side sequentially comprises, from top to bottom, the thermal conductive silica gel pad, the heat uniforming block, the flexible heating sheet, the battery to be tested, the flexible heating sheet, the heat uniforming block and the thermal conductive silica gel pad, and the reference side sequentially comprises, from top to bottom, the thermal conductive silica gel pad, the heat uniforming block, the flexible heating sheet, the reference battery, the flexible heating sheet, the heat uniforming block and the thermal conductive silica gel pad;
• step 3, installing temperature sensors in grooves close to the battery side of sample-side and reference-side heat uniforming blocks close to the battery side, connecting a sample-side flexible heating sheet in parallel to an external constant current and constant voltage source device, and sealing the isothermal calorimetric chamber after an installation;
• step 4, determining charging and discharging parameters and a target temperature of the battery to be tested;
• step 5, starting the calorimeter, controlling a temperature of the heat sink to a constant temperature point lower than the target temperature, and after a temperature of the calorimetric chamber is stable, controlling temperatures of sample-side and reference-side heat uniforming blocks to the target temperature to keep an output power of the flexible heating sheets and the temperature of the heat uniforming blocks stable;
• step 6, performing charging and discharging operations on the battery to be tested, controlling the temperature of a sample-side heat uniforming block to be stable at the target temperature, using the temperature of a reference-side heat uniforming block as a reference temperature, maintaining the temperature of the sample-side heat uniforming block consistent with the temperature of the reference side through temperature sensor feedback control, and recording power changes of sample side and a reference-side flexible heating sheet during charging and discharging;
• step 7, calculating a power change rate using a battery heat generation power, adding a constraint condition of continuity at specified points, and fitting the power change rate through a piecewise polynomial fitting to obtain a fitted heat generation power and a fitted power change rate;
• step 8, obtaining a time constant using charging and discharging data, substituting a measured battery heat generation power, a measured time constant and a measured power change rate into a calibration formula to obtain a corrected battery heat generation power, and completing dynamic characteristic correction;
• step 9, using a power of a reference-side heating sheet as a baseline power, calculating a difference between powers of sample-side heating sheet and the reference-side heating sheet to obtain a real-time heat generation power of the battery to be tested during charging and discharging;
• and
• step 10, integrating the real-time heat generation power of the battery to be tested with respect to time to obtain a heat generation of the battery during charging and discharging.