Any method of winding will disguise almost all the surface area of the separator.
Since each failure begins at a perforation in material that is twenty five microns thick, the capability to monitor all the area is impossible, and sampling the entire cell is not sufficient.
I am sorry, it is not guesswork. It is based on knowledge I have researched, and based my intrpretive skills upon.
Kevlar and Carbon fiber (sic), are not stable in these temperatures, and off gas.
Ceramics is a natural, even as a suitable separator, in and of itself. Porous, heat resistant, and non conductive.
As to certification, the FAA relied almost entirely on the applicant, BOEING, to write its own rules.
I am grateful for the opportunity to have this discussion, Chris.