A convenient convective type dimensionless lumped-capacitance (DLC) method for battery heat generation measurement is proposed. The effective heat transfer coefficient and heat generation can be obtained simultaneously, and no prior calibration of the equipment is needed. The new dimensionless method is verified by reference sample, and the experimental results agree with the theoretical line. The heat generated by a lithium thionyl chloride (Li/SOCl2) battery is measured at the ambient temperature range of 38 degrees C to 50 degrees C. Results reveal that the heat generation is not influenced by ambient temperature at a small discharge current, and the heat generation increases at higher ambient temperature under a higher discharge current condition. The heat generation is approximately proportional to the discharge current in the range of 1.0 A to 5.0 A. The heat generation measurement method can be extended to obtain the heat generated by other types of battery. (C) 2013 The Electrochemical Society. All rights reserved.