The fault with the Boeing Dreamliner Batteries/electrical systems has not yet been found. This is not good news for Boeing since the grounding of 50 aircraft continues. Each grounded aircraft poses a potential claim on Boeing for about $2.5 million per month. The delay in finding the fault also correspondingly delays the selection of a “fix” and the deployment of that “fix”. And since some 850 aircraft have been ordered and production has not been stopped, the fix has to be deployed on a large number of aircraft.
In the absence of any identified fault Boeing are continuing to defend the 787 batteries and I read this as Boeing defending both the design of the chosen batteries and their decision to select these for use. They cannot really do anything else since they cannot acknowledge any potential liability while compensation claims are up in the air (or down on the ground may be more appropriate!).
Airbus apparently has developed a Plan B in the event an alternative to lithium-ion batteries must be found for the A350.
Airbus warned about the risks of lithium-ion batteries at a closed meeting of airlines in March 2011, according to a presentation first reported by Reuters this week.
“We identified this fragility at the start of development and we think we resolved it about a year ago,” Bregier said. “Nothing prevents us from going back to a classical plan that we have been studying in parallel.”
But there is a view that the design chosen by Boeing is fundamentally unsound – that the design lends itself to the possibility of thermal runaways with overheating and subsequent fires. If the design itself is flawed and there are better designs available, then Boeing’s decision process which resulted in using a flawed design could be more damaging than any monetary compensation for the actual groundings. Boeing can ill afford a suggestion that their design or decision process itself is flawed. The current investigation is focused on finding any faults in the units as built and not – yet – on the fundamental design itself.
They can probably absorb the financial hit but my guess is that Boeing will lose considerable ground to the Airbus A350 which could take a long time to recoup.
The lithium ion batteries installed on the Boeing 787 are inherently unsafe, says Elon Musk, founder of SpaceX and owner of electric car maker Tesla.
“Unfortunately, the pack architecture supplied to Boeing is inherently unsafe,” writes Musk in an email to Flightglobal.
“Large cells without enough space between them to isolate against the cell-to-cell thermal domino effect means it is simply a matter of time before there are more incidents of this nature,” he adds.
Both Boeing and Tesla use batteries fueled by lithium cobalt oxide, which is among the most energy-dense and flammable chemistries of lithium-ion batteries on the market. While Boeing elected to use a battery with a grouping of eight large cells, Tesla’s batteries contain thousands of smaller cells that are independently separated to prevent fire in a single cell from harming the surrounding ones.
“Moreover, when thermal runaway occurs with a big cell, a proportionately larger amount of energy is released and it is very difficult to prevent that energy from then heating up the neighboring cells and causing a domino effect that results in the entire pack catching fire,” says Musk.
…. “They [Boeing] believe they have this under control, although I think there is a fundamental safety issue with the architecture of a pack with large cells,” writes Musk in an email. “It is much harder to maintain an even temperature in a large cell, as the distance from the center of the cell to the edge is much greater, which increases the risk of thermal runaway.”
Musk’s assessments of battery cells were confirmed by Donald Sadoway, a professor of electrical engineering at the Massachusetts Institute of Technology.
“I would have used the same words,” says Sadoway. “I’m glad someone with such a big reputation put it on the line.”
“He’s engineered [Tesla’s battery] to prevent the domino effect, while Boeing evidently doesn’t have that engineering,” adds Sadoway. …..
The issue of battery cooling has been at the forefront of the Boeing story for a week. Donald Sadoway, the John F. Elliott professor of materials chemistry at MIT who is involved in a battery startup with Bill Gates, told us last week that a forced air cooling system and sensors may be needed to monitor and cool the battery in the event of overheating. Elton Cairns, a professor of chemical and biomolecular engineering at the University of California, Berkeley, and a fuel cell designer for NASA’s Gemini spaceflights, also suggested that an air- or liquid-cooled system would be necessary.