Are battery charging problems keeping the Dreamliner on the ground?

Boeing is pioneering the use of lithium cobalt ion batteries in the Dreamliner. It's an understandable move, bearing in mind the focus on weight in the aircraft world. Lithium ion offers a higher energy density, so more power can be stored in the same volume or the same amount of power in a smaller battery. But lithium ion batteries are not without their problems – if they are overcharged or subjected to too much heat, they can catch fire. Nokia was forced to recall 46million batteries in 2007 due to the potential for them to overheat and explode, while Sony recalled 10m laptop batteries in 2006. Li-ion batteries need to be charged and maintained in a specific way. Firstly, the cells require a constant current to be supplied. Then a balancing process is applied to make sure each cell is at the same state of charge. Finally, a constant voltage is applied. Charging electronics should also include protection against overvoltage, overdischarge and similar problems. While a battery can catch fire through a manufacturing fault, it's more likely the problem with the Dreamliner lies in the charging electronics – and investigators are now looking in that direction.