PPRuNe Forums - View Single Post - 787 Batteries and Chargers - Part 1
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Old 24th Jan 2013, 01:38
  #118 (permalink)  
RR_NDB
 
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Words on that graph

archae86:

My apologies for the delay in commenting.

I discussed it with him extensively a few hours ago.
Indeed, make us very interested.

The comparison curves were all measured on 18650 cells--a size and form factor often used inside those black brick laptop batteries we have all seen.
Did you use or tested the protected 18650īs?

The cells they use are small enough that the energy release from a single one should not endanger crew or vehicle.
The big adjacent cells in the Thales battery concerns me.

Looking at the Thales/Boeing design and the FAA special considerations, it appears that the approach was to assure cell failure would never occur--as it seems self-evident that no serious measures to avert propagation to adjacent cells were employed, nor were serious measures to contain damage to nearby systems.
TAK incident and specially BOS showed dramatically they failed.

...I wonder if all concerned will remain convinced that all other possible causes of cell failure are sufficiently unlikely to make this approach prudent.
This error is being paid by Boeing with threatening consequences.

Call this Tesla-like.
Tesla just used the perhaps the most important characteristic of a good design:

Fault Tolerance and Graceful Degradation.


It is awkward when "never" happens

...as happened with the IPT disc on a Rolls-Royce Trent 900 on Qantas flight 32, and has happened on these two 787 episodes. Examples everywhere.

Thanks again for excellent post and answer.
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