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Isothermal Battery Calorimeters

National Renewable Energy Laboratory

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Technology Marketing Summary

The automotive industry has turned to lithium-ion batteries as the energy-storage technology needed to make electric-drive vehicles viable for a wider market. Precise battery-temperature control is crucial to battery longevity and safety, as demonstrated by recent issues with accelerated lithium-ion battery degradation in certain electric vehicles and, more dramatically, battery fires in commercial airplanes. The Isothermal Battery Calorimeters (IBCs) are the only instruments able to support the diagnosis of these types of battery thermal-management issues.


Understanding and controlling temperature is necessary for the successful operation of battery packs in electric-drive vehicles. The chemistries of advanced energy-storage devices—such as lithium-based batteries—are very sensitive to operating temperature. High temperatures degrade batteries faster while low temperatures decrease their power and capacity, affecting vehicle range, performance, and cost. Understanding heat generation in battery systems— from the individual cells within a module, the inter-connects between the cells, and the entire battery system—is imperative for designing effective thermal-management systems and battery packs.

The Isothermal Battery Calorimeters (IBCs) very accurately measure the heat generated from a battery (with a baseline sensitivity of 10 milliwatt and heat detection as low as 15 joules) while being charged and/or discharged. Batteries of various sizes—from coin cells to small packs with multiple large-format cells—can be tested over their entire operating range. The battery test chamber, which is completely submerged in an isothermal bath, uses highly sensitive and accurate heat-flux gauges. All sensory and power cables to the battery are carefully designed and routed to minimize erroneous heat losses or gains. The IBC test chamber is the only technology that features a safety pressure-relief design to vent gases in case of battery malfunction.

For further information regarding NREL’s IBC technology, please visit NREL’s website here.

  • Thermal characterization solutions for manufacturers and investors pursuing the multi-billion-dollar Electric Drive Vehicle (EDV) market.
  • Reliable testing capability for battery packs of all sizes.
  • Safety assurance for lithium ion battery producers and users.
Applications and Industries
  • Evaluation of EDV automotive batteries
  • Energy storage devices and “smart grid” technologies, including systems incorporating renewable resources such as solar and wind.
  • Li-ion battery design for military, aviation, and space applications
  • Additional measurement from any number of sources, including power electronics, such as power converters and inverters, supercapacitors and asymmetric capacitors for advanced vehicles.
More Information

Related Patents:

US 9,476,780 B2    CN 103492846B             EU 2684016    

CH 12758345        DE 60 2012 037 5876     JP 5908927   

Patents and Patent Applications
ID Number
Title and Abstract
Primary Lab
Patent 9,476,780
Calorimeters for testing energy storage systems and power electronics methods of making the same and methods of use
Large volume calorimeters (100) and small volume, or cell, calorimeters (700), as well as methods of making and using the same, are provided.
National Renewable Energy Laboratory 10/25/2016
Technology Status
Technology IDDevelopment StageAvailabilityPublishedLast Updated
ROI 11-19 and ROI 11-102LicensedAvailable09/17/201809/17/2018

Contact NREL About This Technology

To: Erin Beaumont<>