Electric airliner
Join Date: Nov 2004
Location: Perth - Western Australia
Age: 75
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Batteries will only become highly competitive within the aviation field when an inventor or a group of researchers can produce a lightweight version.
Until that time (which I cannot see happening within the next 20 years - but I've been wrong, once), then the sheer, unavoidable heavy weight penalty of batteries will mean that they will be limited to equipment and processes that are strictly ground-based.
Until that time (which I cannot see happening within the next 20 years - but I've been wrong, once), then the sheer, unavoidable heavy weight penalty of batteries will mean that they will be limited to equipment and processes that are strictly ground-based.
No, I define it as being "operation within the specification and procedures defined in their certification"
The 787 batteries were being used outside their specification due to a design oversight. The issue has been identified and rectified, which is why they have been returned to service. I'm not at liberty to discuss that further.
The samsung cells (they weren't batteries) had a manufacturing error which produced internal shorts in the batteries, and the phone had a design error which packaged the cell with insufficient space around it for expansion in charging (the phone design failed to implement the design specifications of the cell manufacturer). The cell manufacturing defect was rectified, but the phone design deficiency couldn't be addressed without changing the external dimensions so they were withdrawn.
The design flaws I referred to are in the products using the cells, not the cells themselves. If you attach a wing to an airliner with four M10 high-tensile bolts it is likely that the bolts will fail with catastrophic consequences. This design error would not make the bolts themselves inherently dangerous.
That's a rather silly argument, IMHO. If we follow that argument then we should prohibit all new forms of transport that use onboard energy supplies. On an aeroplane we have multiple instances of stored high-density energy from the fuel and batteries to the pressurised fluids in control/braking systems and the life-support systems. At various times failures due to design, manufacturing or operating errors in every single one of these have had catastrophic consequences, but we haven't banned the concept of future development as a result. Heck, the pressurised cabin constitutes a MASSIVE amount of stored energy (at altitude) and a failure to understand the failure modes of structures of the containing structure cost hundreds of lives, but we never considered banning pressurised cabins while we were tying it down.
The failure modes of current lithium cells ARE understood, and were fully understood long before they were certified in aircraft installations. If we develop another electrical storage technology then its failure modes will be subjected to extensive testing long before it gets onto any airborne platform. Everything we bolt onto, carry inside or employ as part of the use of aeroplanes is subject to the same detailed investigation and clearance process before use, so a blanket "we must never use mega-batteries in aeroplanes because it will offend the ancient gods" attitude seems a little excessive IMHO.
PDR
The 787 batteries were in normal operation when they caught fire.
The Samsung batteries were in normal operation when they caught fire.
That they did so due to design flaws merely reiterates my point that they catch fire in normal operation unless you're very careful with the design.
We don't understand the disastrous failure modes of yet-to-be-invented-mega-battery.
The failure modes of current lithium cells ARE understood, and were fully understood long before they were certified in aircraft installations. If we develop another electrical storage technology then its failure modes will be subjected to extensive testing long before it gets onto any airborne platform. Everything we bolt onto, carry inside or employ as part of the use of aeroplanes is subject to the same detailed investigation and clearance process before use, so a blanket "we must never use mega-batteries in aeroplanes because it will offend the ancient gods" attitude seems a little excessive IMHO.
PDR
