Intended to provide backup power for the newest A350 jetliners, lithium batteries are more powerful, lighter and require less maintenance. Escalating arguments about the extent of safeguards and testing for such rechargeable batteries—reminiscent of Boeing Co.’s difficulties with similar technology years ago—come after European regulators already have approved the Airbus systems based on less-stringent requirements.
http://www.wsj.com/articles/airbus-faa-spar-over-lithium-batteries-1469611983