Hi,
Dtype:
Aeroplanes have been living with fire (in their engines) for over 100 years. This COULD be a precedent for permitting (inadvertent) fires in another power source, the batteries, provided it was as well contained as the engine combustion???
You introduce an important point: We operate (and live with) machines with contained fires. What is not accepted is:
A company introduce a new design (under special "conditions") and in an interval of days two planes suffer incidents with HEAT, SMOKE and FIRE (BOS). The second (TAK) was bound to be much worse. A short circuit saved Boeing discharging the battery thus avoiding an in flight fire in a compartment with important electronics. (This is a model posted and commented earlier)
The technical answer is:
A dependable and safe battery (one that not is transformed suddenly in a dragon: heat, smoke and even fire) is absolutely required. A battery (that could caught fire) well contained with "normal" MTBF will be certified.
Problem now is not only technical. Became almost a "political" issue with not small technical challenges.
(*) No powered plane without fire. There are
powered planes (electric motor) with these batteries.
saptzae:
IMHO will draw less than 7.5KW (300A x 25V).
Good estimate
These LiCoO2 cells are de-rated to 4.025V, and should not show any anomalies after a few months / a few hundred flight hours.
What really happened?
Just random? Coincidence?
FlightPathOBN:
In the re-design, go back from 32V to 24V..
32 V was designed due BDM (diode module)
ITman:
I am sure that these issues were considered in Mr B's design,...
We detected errors so, we are not so confident on that.
Hi_Tech
2. Is it just a coincidence that we have 2 fire incidents in one month.
One fire incident in BOS (Logan) TAK had heat, smoke and hot chemical spray (battery lost 5 Kg)
3. Surely the battery would have gone through a rigorous testing before manufacture and it is difficult to imagine that there were no problems at all with this compact design of a highly volatile chemistry.
We donīt know. This is a Testability issue.
TURIN:
Someone at Boeing got their wires crossed.
The disconnection seems not just between engineers at Seattle and Chicago high rocks.
cockney steve:
Some bean-counter's being grossly overpaid for a stupendous level of incompetence!
green granite:
It then has the ability to recharge in a relatively short period of time so that it is available for the critical backup role that it plays during flight.
Logical question!