A battery analysis device for a battery module having at least one battery cell includes a power source supply unit, a signal capturing unit, a signal adjusting unit, a frequency domain analyzing unit, a time domain analyzing unit, and a processing unit. The power source supply unit provides a variable-frequency voltage signal to a battery cell. The signal capturing unit captures a current signal generated by a battery cell in response to the variable-frequency voltage signal. The signal adjusting unit adjusts the variable-frequency voltage signal and the current signal. The frequency domain analyzing unit and time domain analyzing unit analyze both the adjusted variable-frequency voltage signal and the adjusted current signal in frequency domain and time domain respectively for obtaining a frequency domain parameter and a time domain parameter. The processing unit obtains electrochemistry characteristics of the battery cell according to the frequency and the time domain parameters.