2013 R&D 100 Winner
Isothermal Battery CalorimetersUnderstanding and controlling temperature is necessary for the successful operation of battery packs in electric-drive vehicles (EDVs). Isothermal Battery Calorimeters (IBCs), developed by National Renewable Energy Laboratory (NREL) and NETZSCH North America LLC, are the only calorimeters that can accurately measure heat generated from batteries used in EDVs—with a baseline sensitivity of 10 mW and heat detection as low as 15 J—while being charged and/or discharged.

NREL engineers applied key principles of thermodynamic, heat-transfer, thermoelectric and electrochemical theory to the development of the IBCs. The design is based on isothermal heat-condition calorimetry, which means that a test sample and its surrounding fluid are at the same initial and final uniform temperature. The principle of single-ended conduction means that there are no control test samples to subtract heat leakage or other errors created from various sources. The IBCs are the only calorimeters to eliminate outside environmental variables by surrounding the test chamber on all six sides with an isothermal bath fluid.


National Renewable Energy Laboratory
NETZSCH North America

Development Team

National Renewable Energy Laboratory's Isothermal Battery Calorimeters development team.


NETZSCH North America's Isothermal Battery Calorimeters development team.


The Isothermal Battery Calorimeters Development Team
Matthew Keyser, Principal Developer, National Renewable Energy Laboratory
John Ireland, National Renewable Energy Laboratory
Dirk Long, National Renewable Energy Laboratory
Jean-Francoi Mauger, NETZSCH North America
Mark Mihalic, National Renewable Energy Laboratory
Ahmad Pesaran, National Renewable Energy Laboratory
Peter Ralbovsky, NETZSCH North America
Gilles Widawski, NETZSCH North America