The battery problem that last year afflicted Boeing's worldwide fleet of 787 Dreamliners appears to have recurred. Japan Airlines grounded its 787s Wednesday after workers noticed smoke emanating from a battery pack on a 787 they were checking before a planned flight out of Narita Airport, in Tokyo.
Last year's problems also involved a JAL airliner, which was in Boston's Logan Airport at the time. A Nippon Air 787 was similarly affected two weeks later.
What happened this time around is still unclear.
Last year, though, the culprit was thermal runaway—a self-accelerating reaction that causes a battery to release energy all too quickly. Some critics blamed the choice of lithium-ion battery technology, which saves an insignificant amount of weight in the plane's design and is only a bit more convenient than the old metal-hydride batteries were. Others cast aspersions just on the particular anode chemistry that Boeing had chosen for the battery—a chemistry that was efficient but relatively volatile. A different criticism was offered by Elon Musk, who pioneered the use of lithium-ion batteries in his Tesla car. He said that Boeing should have used a larger number of smaller cells and insulated the cells more effectively from one another.
In the end, Boeing got the 787s back in the air with a workaround involving a thicker containment vessel that included heat sensors and a venting system. Whether that system worked yesterday in Narita is not yet known.
