You raise a really good point about the reasons for Musk's collaboration, Nadine. Obviously, no one but Musk knows the full reason, but I imagine there is an element of self-preservation in this. Lithium-ion batteries are getting a going-over in the popular press right now, and some news stories have wondered aloud if lithium-ion is appropriate for electric vehicles. Whether those questions are fair or not, I would imagine that Musk wants people to know that Tesla's battery configuration works safely because the design allegedly makes better allowances for heat dissipation. It's hard to blame him for that.
Regarding the issue of whether a battery management IC, by itself, was sufficient protection for the Boeing batteries: We asked Donald Sadoway of MIT that question by e-mail, and his response came in after the story deadline. So here's his response, which arrived late yesterday: "We have evidence that whatever the electrical demands are in the 787, the IC alone doesn't prevent fire. So perhaps the IC isn't right, perhaps the IC is right but the execution is flawed, or perhaps there is some other factor like decompression/compression, which is the result of ascent and descent."
As an alternative to overcharging and heat dissipation how about over discharging? Over discharge damage is the reason many RC enthuiasists charge their lithium ion batteries outside.
Boeing has recieved 100 batteries back from the airlines as defective. It appears the majority have been inadvertently discharged until the battery low voltage cutoff tripped, disabling the battery. In ANA's case 5 of 10 returns were disabled by the low voltage cutoff. Once a lithuim ion battery has gone below the low voltage limit it is very hazardous to charge. It seems risky procedure for the user to bang up against only battery safety stop during routine ground maintenance. Maybe some batteries have very nearly tripped but were unknowingly flown.
Anticipating the question of why don't the battery electronics cut off discharge at a higher voltage, I don't know. It might have something to do with the fact the batteries are also a last ditch power source to keep flying. I can imagine a situation where you would want every joule you could get out of the battery and willingly scrap it later.
I would discount poor high altitude cooling. The batteries are in the pressurized part of the plane, an equivalent to an altitude of 6000 feet so you still have good heat transfer.
Great that you're keeping on top of this story, Charles. I guess now what we're waiting for is Boeing to admit what it has done wrong and then come up with a plan to fix the problem. I was sort of defending them at first but it actually seems like a fairly major oversight to not proivide a proper cooling system...but maybe they thought they did and it was just an honest mistake. I will continue reading your coverage to see how this unfolds! Let's hope it's a good ending for everyone and Boeing sorts this out.
Wow. Thanks for this, Chuck. Definitely a developing story. I'm delighted to hear that there is collaboration (or at least a coalition) of lithium-ion battery users that are willing to swap experience with these systems. I'm sure this type of information sharing between CEOs has happened since the dawn of time, but I'm encouraged that it can be facilitated by social networking such as twitter and not left to chance meetings on the putting green at the club. I'm sure networking at the Engineer level is still best found at the Dearborn Heights Applebee's, but online story swapping is another emerging development that helps to accelerate the exponential technology development curve...
More often than not, with the purchase of a sports car comes the sacrifice of any sort of utility. In other words, you can forget about a large trunk, extra seats for the kids, and more importantly driving in snowy (or inclement) weather. But what if there was a vehicle that offered the best of both worlds; great handling and practicality?
Science fiction author Isaac Asimov may have the best rules for effective brainstorming and creativity. His never-before-published essay, "On Creativity," recently made it to the Web pages of MIT Technology Review.
Much has been made over the potentially dangerous flammability of lithium-ion batteries after major companies like Boeing, Sony, and Tesla have grappled with well-publicized battery fires. Researchers at Stanford University may have come up with a solution to this problem with a smart sensor for lithium-ion batteries that provides a warning if the battery is about to overheat or catch fire.
Focus on Fundamentals consists of 45-minute on-line classes that cover a host of technologies. You learn without leaving the comfort of your desk. All classes are taught by subject-matter experts and all are archived. So if you can't attend live, attend at your convenience.