Thermal Storage Phase Change Material Composites

Physical Sciences : Materials and Compounds

Available for licensing


  • Li Shi, Ph.D. , Mechanical Engineering
  • Rodney Ruoff, Ph.D. , Mechanical Engineering
  • Christopher Bielawski, Ph.D. , Chemistry and Biochemistry
  • Alexandre da Silva , Mechanical Engineering
  • Hengxing Ji , University of Texas at Austin
  • Abhijit Paul , University of Texas at Austin
  • Daniel Sellan , University of Texas at Austin
  • Evan Fleming , Mechanical Engineering
  • Shaoyi Wen , Microelectronics Research Center
  • Eunsu Paek , University of Texas at Austin
  • Michael Pettes , University of Texas at Austin
  • Alexander Pak , University of Texas at Austin

Background/unmet need

In order to drastically improve the driving range of an electric vehicle (EV), the efficiency of the on-board HVAC system needs to be improved significantly. Traditional HVAC system can reduce the range of an EV by as much as 30 percent, especially in warm climates. Innovations in both materials and design engineering in the climate-control system are necessary to make future EVs practical and comfortable. Thermal battery is one such technology. A thermal battery modulates the air temperature through storing and discharging thermal energy as needed. But the materials and system design are critical in achieving desired energy storage capacity and efficiency.

Invention Description

UT Austin researchers have made major discoveries in materials science and in system integrations of a thermal battery system, including:
1. Novel Phase-Change-Materials (PCMs) with high latent heat of fusion/melting
2. Novel hybrid material to be filled with PCM to form a high thermal conductivity composite for the heat reservoir
3. 3-D printed graphite structures that can be used to form the PCM composites or as heat exchanger 
4. A thermal storage unit consisting of a shell and tube heat exchanger with the inclusion of PCM-foam composites


  • Lower melting point of the PCM fulfills the need of medium temperature range for organic PCMs.
  • Uniform 3-D interconnected foam structure is lightweight with excellent thermal conductivity, and improves the power density of PCM-based thermal battery.
  • Using 3-D printing process to form a graphite template for the heat exchanger, PCM composite storage, and other applications provides design flexibility and high quality.


  • Higher thermal energy density with medium-range melting point and high heat of fusion
  • Porous carbon foam made of carbon nanotubes provides perfect composite material with high porous volume and high heat conductivity.
  • Flexibility in design geometry and consistent high quality for forming heat exchangers, storage units and other structures
  • A shell/tube configuration that can accommodate PCM composite foams
  • Better heat transfer through PCM-foam composites that can be flown through the innovatively designed shell/tube configuration

Market potential/applications

Climate control system of EVs; industrial thermal storage units; residential HVAC systems

Development Stage

Lab/bench prototype

IP Status

  • 1 foreign patent issued
  • 1 U.S. patent application filed

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