Area increases as a square of diameter, and the square root of 1000 is 31, so 1/30th as thick seems about right. Current state of the art battery packs run at

Area increases as a square of diameter, and the square root of 1000 is 31, so 1/30th as thick seems about right. Current state of the art battery packs run at 800V. Making a 10kV pack would be difficult. 10MW is about the size of the largest wind turbines so maybe a wind turbine engineer could help you.