Aviation Week interviewed Boeing CEO Jim McNerney.
Aviation Week: "In retrospect, was the amount of weight you saved with Lithium Ion batteries a case of too much risk for too little reward?"
McNerney: "It's not as simple as a weight-reduction-gone-awry conclusion because we get added capability from this battery, such as its capacity to quickly charge. In an all electric airplane, its a more capable battery.
Yeah right. Added capability is bafflegab. All a battery can do is supply electricity. As far "quick charging" and "all electric airplane", all the battery has to do is get the engines started. Then the aircraft runs off generator power. As long as the battery recharges before the engines shut down at the end of the flight, all is well.
In actual fact, some one at Boeing got carried away with the coolness of lithium batteries and did not bother to consider the fire hazard, which might not have been clear when the 787 was first conceived back in the late 1990's, but was pretty obvious by 2003 or 4. Everyone else in the industry dropped lithium battery plans after they started catching fire in the 787.
2 comments:
If Boeing had used LiFePO4 Li-Ion batteries rather than the more dangerous LiCoO2 batteries, the chances are the fires would have never taken place. The cobalt-based chemistry is a lot less stable and more prone to thermal runaway. The iron-based chemistry tends to be safer, can handle higher discharge/charge currents, and is highly resistant to thermal runaway. It's one reason automakers use them in hybrids rather than the cobalt-based cells. While the lithium iron phosphate don't have quite the energy density of the cobalt-based cells (about 95% of the cobalt cells) they're a heck of a lot safer and still have the advantages over the lead-acid AGM batteries they would have likely used.
I've heard that from other people. I'm not deep enough into Lithium chemistry to know one way or another. As things turned out Boeing would be better off if they had gone with nickel cadmium, nickel metal hydride, or even good old lead acid.
Would have saved them a $500,000 refit per plane, loss of $200 million apiece 787 sales, and another load of bad press.
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