High Energy Density Thermal Batteries

High Energy Density Thermal Batteries

Project Term:
11/15/2011 - 03/31/2015

Critical Need:

The transportation sector is the dominant source of U.S. dependence on foreign oil and a major contributor of greenhouse gas emissions. Enabling more widespread use of electric vehicles (EVs) would reduce both our dependence on foreign oil and our harm to the environment. Inefficient heating and cooling systems can limit the driving range of EVs by acting as a drain on their batteries. More efficient technologies are needed to provide heating and cooling to EVs without draining the on-board battery packs, in effect extending the driving range of EVs per electric charge. These efficient technologies may also enable thermal management of internal-combustion engine vehicles.

Project Innovation + Advantages:

Sheetak is developing a new HVAC system to store the energy required for heating and cooling in EVs. This system will replace the traditional refrigerant-based vapor compressors and inefficient heaters used in today's EVs with efficient, light, and rechargeable hot-and-cold thermal batteries. The high energy density thermal battery—which does not use any hazardous substances—can be recharged by an integrated solid-state thermoelectric energy converter while the vehicle is parked and its electrical battery is being charged. Sheetak's converters can also run on the electric battery if needed and provide the required cooling and heating to the passengers—eliminating the space constraint and reducing the weight of EVs that use more traditional compressors and heaters.

Potential Impact:

If successful, Sheetak's supplemental thermal energy storage system could achieve lower cost and higher energy storage densities than conventional heating and cooling systems.


Increased use of EVs would decrease U.S. dependence on foreign oil—the transportation sector is the dominant source of this dependence.


Greater use of EVs would reduce greenhouse gas emissions, 28% of which come from the transportation sector.


This technology would increase the marketability of EVs—helping spur growth in the automobile industry.


ARPA-E Program Director:
Dr. James Klausner
Project Contact:
Dr. Uttam Ghoshal
Press and General Inquiries Email:
Project Contact Email:


Delphi Automotive Systems, LLC

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