Q: Had Boeing chosen all nickel-cadmium batteries instead of lithium-ion batteries for its 787 Dreamliner, how much additional weight would have been added to the plane?
A: One nickel-metal hydride battery weighs about 100 pounds, or about 40 pounds more than a lithium-ion battery, Donald Sadoway, a battery expert and materials chemistry professor at MIT, told Q-and-A on the News in an email. There are two lithium ion batteries — one for power backup and one for engine ignition — on every 787 Dreamliner, Sadoway said.
“That means a difference of about 40 pounds per battery, which is less than the luggage allowance for a single passenger," Sadoway wrote. He wrote that nickel-metal hydride batteries are used in the Toyota Prius.
All 50 of Boeing’s 787s were grounded earlier this month during an investigation to find out why lithium-ion batteries failed on two planes. One caused a fire on a 787 and another forced an emergency landing.