Battery device temperature measurement method

The purpose of the present invention is to provide a battery device temperature measurement method for accurately measuring the internal temperature of a battery device with respect to a conventional battery device temperature measurement method in which the measured value of an internal impedance to be measured is affected by the state of health of a battery device and varies and therefore the accurate internal temperature of the battery device cannot be obtained. The present invention is characterized in that the internal impedance of a battery device (1) is measured using a signal having a frequency of, for example, 10 kHz or more which is difficult for the ions in the battery device (1) to follow and the internal temperature of the battery device (1) is calculated from the measured value of the internal impedance.