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NASA Lends Researcher for Battery Development

January 18, 2010

Developing safe batteries for commercially viable electric vehicles is challenging, but factor in a thermal, vacuum, and zero-gravity environment like outer space, the task is downright daunting. Either way, NREL and NASA are working toward similar goals: creating large, high-performing lithium-ion (Li-ion) battery solutions for vehicles that are safe and reliable.

To move both agencies toward this goal, NASA's Eric Darcy recently joined NREL's Transportation Technologies and Systems Center as part of NASA's Innovation Ambassador Program. Darcy will work with the Energy Storage Team for nine months to develop, model, and design safety measures for Li-ion batteries for terrestrial or space-electric vehicles.

"I chose to come to NREL because the battery experts at NREL are leaders in simulating battery performance under abusive conditions, which are critical for rapidly and effectively enabling safe designs," said Darcy. "And I'd like to go back to NASA as a battery expert with enhanced mathematical modeling skills."

About 75% of Darcy's time will be devoted to NREL projects. In particular, he will conduct experiments on battery materials and develop mathematical models to better understand and mitigate thermal abuse in Li-ion batteries for advanced vehicles. Darcy will also help the lab begin modeling the behavior of several battery overcurrent and overcharge hazard control measures.

The rest of his time will be spent continuing and sharing with NREL two projects he oversees as NASA-Johnson Space Center's Battery Group Lead. The first is developing a safe, light-weight Li-ion battery for the 75kW power system in the International Space Station. The team is currently in the critical cell design selection stage, and they are working to identify the design with the lowest propensity to have latent defects that could become catastrophic. The second is creating a light-weight battery pack for NASA's "Robonaut". The Robonaut—designed with exacting human likenesses, including joints, hands, and feet—is being designed to travel to the moon, collect samples, and relay video images. The Robonaut is intended to demonstrate the usefulness of advanced lunar robots that could eventually work side by side with suited astronauts, so a safe, reliable battery is imperative.

"The average catastrophic failure rate for commercial Li-ion cells in batteries from reputable manufactures is about one in a million," said Darcy. "For NASA's expensive and high-visibility manned missions, we need rates to be closer to one in a billion or less, which are achievable thanks to mitigating measures that I look forward to discovering with my NREL colleagues."

Darcy has 23 years of electrochemical engineering experience focused on batteries dating back to his graduate studies modeling electrode phenomena. He received his Ph.D. in chemical engineering from the University of Houston.