Experimental study of the heat generations of Li/SOCl sub(2) and Li/SO sub(2) batteries using a phase-change measurement method

A paraffin phase-change measurement method for the heat generation of spirally wound cylindrical Li/SOCl sub(2) and Li/SO sub(2) batteries at different ambient temperatures and discharge currents is proposed. The electrical and thermal insulations of the measurement system have been greatly improved, and the accuracy of the measurement system is 4.6 % based on calibration experiments. Compared with accelerated rate calorimetry, isothermal microcalorimetry, and radiation calorimetry methods, the phase-change measurement method is simpler, but with a high accuracy. The experimental results reveal that the heat generation of the batteries during discharge is weakly dependent on the ambient temperature in the range of 38-50 degree C, but strongly affected by the discharge current. As the discharge current increases, the heat generated by the Li/SOCl sub(2) and Li/SO sub(2) batteries increases as a quadratic polynomial function. The Li/SO sub(2) battery generates more heat than the Li/SOCl sub(2) battery at the same discharge current, which is demonstrated by the qualitative analysis of the internal resistance. Furthermore, the phase-change measurement method for heat generation has a strong universality, and can be applicable for heat generation measurement of various battery types.