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NREL-Analyzed Battery Journeys into Outer Space with Space Shuttle Endeavor

June 6, 2011

NASA's space shuttle Endeavor took its final mission into space on May 17, 2011. Also onboard were NREL-analyzed batteries used to power the astronauts' spacesuits during spacewalks. The astronauts completed these walks while wearing spacesuits powered by a battery consisting of 80 high energy, laptop-sized lithium ion cells (Li-ion). NREL performed analysis for NASA, using enhanced version of safety models developed under the U.S. Department of Energy (DOE) Energy Storage R&D program, to validate confirm the safety design of the battery under conditions that are not easily validated with testing.

This is the first time that NASA's spacewalks have been powered by Li-ion batteries, an improvement over the previous Ag/Zn design. In the last four years, NASA engineers at Johnson Space Center (JSC) have taken every step to make the battery safe during shuttle launch, storage, and operation. In 2008, through an Interagency Government Agreement, NASA began utilizing NREL expertise to evaluate and validate the new spacesuit battery safety features. NREL's Energy Storage Team has worked with NASA-JSC engineers and their partners to develop an experimentally-validated electrical-thermal-chemical network model of the 80-cell Li-ion battery. In 2010, NASA-JSC assigned their lead battery engineer, Dr. Eric Darcy, to work at NREL as a NASA Innovative Ambassador. Darcy worked with an NREL team that consisted of Ahmad Pesaran, Gi-Heon Kim, Kandler Smith, and Larry Chaney.

According to Darcy, "the results of NREL's analysis identified the narrow range of short circuits internal to the battery that are not controlled by its design features and could result in thermal runaway. The results were an important portion of the rationale needed for NASA to accept the residual risk of this hazard."

"Lithium ion battery safety is critical and similar for spacewalks and electric-vehicle drives alike," said Project Lead, Ahmad Pesaran. "Overcoming safety hurdles of lithium ion batteries is essential for widespread adoption of electric vehicles to reduce dependence on imported oil and lower greenhouse gas emissions."

More information on the space shuttle Endeavor's mission can be found on NASA's website.