I've been following the unfolding saga of the lithium-ion batteries used on Boeing's much-praised 787 Dreamliner aircraft. It seems some of these are catching fire, and I couldn't help but think back to a few years ago (and a few occasions since) when notices of overheating lithium batteries in notebook computers were reported. At the time, it was noted that lithium batteries must be very carefully recharged so as not to cause overheating and possible consequential ignition. And so my first assumption when reading of the 787's problems was a possible design or implementation flaw in the charging system, including its software, or perhaps something related but more systemic in nature. I saw reports as late as yesterday, though, that there doesn't appear to be such a flaw, and so perhaps the problem lies in an individual faulty battery cell - again, an implementation or perhaps design flaw. I'm sure this problem will be found to be relatively minor, properly addressed, and that the Dreamliner's destiny as a truly great aircraft will absolutely be realized.
Still, if a battery used in an aircraft application (the very definition of mission-critical) can fail, what about all those mass-produced lithium batteries that we all depend upon today? Increasingly, these are sealed in end-user devices (iPhones and iPads come immediately to mind) and can't be easily swapped or replaced. I've argued against non-removable batteries in the past as a matter of convenience and utility, but I do understand the need to protect the environment and gain fundamental economic benefits by recycling used cells. Still, a flaw in a battery could result in major expense for device manufacturers and associated downtime for us users - and possibly outweighing the benefits of closed implementations.
But it's also clearly possible to build better-than-sufficient control systems into batteries and related electronics, monitoring not only for charging/discharging (what "smart batteries" do), but also for temperature and consequential action when an alarm is triggered - and, as lithium cells with both of these capabilities exist today, the 787's problems are all the more curious. Yes, these features add cost, but there is likely no alternative. A fire on an aircraft resulting from a failing lithium cell in a handset can be just as dire as one originating in an equipment bay on that same aircraft. The Department of Transportation already has restrictions on lithium cells in place - although I wasn't aware of these, and I wonder how many people are and how these are enforced. There's a lot to consider, not to mention do, here.
Lithium power technology is essential to mobility of any form. It's the lightest metal, and it's unlikely any alternative battery technology will replace lithium anytime soon. As an engineer, I understand the challenges of building intrinsically-safe power cells, but I believe we can do it. Occasional failures, as we've seen in this case, are to be expected. But we need to do a much better job of testing and perhaps even designing these products before they go into service. And that's true whether we're talking aircraft - or handsets.