"The battery, made by Japan’s GS Yuasa, was Boeing’s choice for the 787’s design in 2005, which Laslau says is unfortunate because its cathode was based on cobalt oxide. “The cobalt oxide chemistry that Boeing chose has a fantastic energy density, but it’s not the safest. Lithium iron phosphate would be safer,” he says. But the iron phosphate alternative wasn’t well developed seven years ago."
Boeing Battery Blues
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I still feel that a circular wind is needed..the thermal expansion would be radial and transferred along the length. Hopefully, they would be smart enough to wind it with the proper thermal spacing.
With a square wind, you have the ability to create a bend during manufacture, but even if you dont, the thermal expansion will keep hitting the corners and eventually may degrade the winding.
There is also the compression/decomp of normal aircraft ops on the battery itself