Northeastern researchers on the Boeing battery failures

Photo via Thinkstock.

Photo via Thinkstock.

By now you’ve prob­ably heard of the Boeing 787 Dream­liners and the prob­lems they had in their first weeks in the air. Basi­cally, the Dream­liner is an extremely fuel-​​efficient air­liner. It was the first to use com­posite mate­rials to reduce weight and the first to use “large format” lithium-​​ion batteries.

Due to fuel leaks and spon­ta­neous fires in the bat­teries that exceeded the normal growing pains of any new, com­plex system, the entire fleet was grounded in mid Jan­uary. Today, Chicago Tri­bune reports that the Fed­eral Avi­a­tion Admin­is­tra­tion has per­mitted Boeing to per­form a single “ferry flight” to relo­cate one of their planes so they can con­tinue inves­ti­ga­tions. There is still no con­clu­sion about the cause of the fail­ures and FAA and National Trans­porta­tion Safety Board offi­cials don’t expect one for at least a couple months.

I wanted to better under­stand the problem so I asked North­eastern researchers K.M. Abraham and Peter Mano­lios for the takes on it all. Abraham is a research pro­fessor in the North­eastern Uni­ver­sity Center for Renew­able Energy Tech­nolo­gies with 30 years of expe­ri­ence in the world of lithium bat­teries. He was quoted in two recent Wired arti­cles about Boeing’s trou­bles, here and here. Mano­lios is an asso­ciate pro­fessor of com­puter and infor­ma­tion sci­ence who has worked with Boeing and NASA for nearly a decade. The Dream­liner team com­mis­sioned Mano­lios to build an algo­rithm (dubbed CoBaSa) that can auto­mat­i­cally inte­grate the var­ious safety sys­tems onboard the plane.

Abraham explained that lithium-​​ion bat­teries are such a hot topic (pun not intended) because they can store up to ten times more energy  than tra­di­tional bat­teries. This is what makes them so energy effi­cient but it is also pre­cisely why they carry poten­tial safety haz­ards. It’s the dif­fer­ence between taking a match to a couple grains of gun­powder or a hand grenade full of the stuff.

Now imagine the gun­powder is in the same vessel as a lit match, and a polymer mem­brane about half the thick­ness of a human hair is the only thing sep­a­rating the two. This is akin to the sit­u­a­tion in a lithium-​​ion bat­tery, where the mem­brane sep­a­rates two chem­ical reagents that are highly reac­tive with one another. Any fail­ures in the system could allow the two chem­i­cals to come into con­tact (inter­nally short cir­cuit), which would mean cer­tain death for the battery…and a big explosion.

Lithium-​​ion bat­teries are per­va­sive these days. They’re in our cell phones and our com­puters. They’re the sole power storage devices in all elec­tric vehi­cles like the Nissan Leaf and Tesla Road­ster. All told, Abraham said there are more than 10 bil­lion lithium-​​ion bat­teries out there, pow­ering our dig­ital world one chem­ical reac­tion at a time. But that’s no reason to get into a tizzy, as my mom would say. The bat­teries in these devices have gone through exten­sive opti­miza­tion steps over the years. The chance of a fire in any of them is about one in 10 million.

According to the press, the Dream­liner bat­teries were also man­u­fac­tured according to accepted spec­i­fi­ca­tions. It could be, Abraham spec­u­lated, that the spec­i­fi­ca­tions rel­e­vant in the small-​​format bat­teries in our cell phones and elec­tric cars simply aren’t  enough at the larger scale.

The real problem may also have stemmed from how the bat­teries were used, said Mano­lios. “What seems to have hap­pened is that there was a very large demand placed on the bat­teries and while they were charging they caught on fire,” he explained, pointing to a Time Mag­a­zine article on the topic.

While Mano­lios’ CoBaSa algo­rithm wasn’t designed to detect bat­tery fail­ures or fuel leaks, it’s pos­sible that it could be used to pre­vent the former, he said. “We used my algo­rithm to syn­the­size soft­ware archi­tec­tures, which involved fig­uring out which cab­i­nets to place avionics code on, sub­ject to a very large number of declar­a­tive con­straints,” he said.

It seems likely that we could use CoBaSa to express con­straints saying that the power demands to the bat­tery do not exceed a par­tic­ular limit.” CoBaSa could then syn­the­size a system that doesn’t demand more power than the bat­tery can pro­vide, he explained.

Abraham is taking another approach, working on entirely new sys­tems. He invented a bat­tery called lithium-​​air, which uses oxygen from the atmos­phere as the [cathode] and is sig­nif­i­cantly less haz­ardous than those described above. “It’s still in the early stages,” he said, “but there’s a world­wide effort in making it a prac­tical battery.”

Ulti­mately, we’ll have to wait for the results of Boeing’s field tests to know exactly what hap­pened. But I think it’s impor­tant we not put this down in the record books as a fun­da­mental flaw in lithium bat­tery tech­nology. There are loads of researchers in the world, and sev­eral at North­eastern, all fig­uring out ways to make safe energy-​​efficiency a tan­gible goal.