Why re-invent the Wheel?
I was interested by your article on the design of a standard plug for connecting e-cars to the mains for charging.
We manufacture under license in U.K. the Auto-Eject which is a shoreline connection system. We have sold 10,500+ in U.K. & Ireland and it sells around 20,000 units p.a. in U.S.A.
As it Auto-Ejects it negates the need for a drive-disabling system, and is used in conjunction with the Auto-Safe switch on the wall or post which gives an immediate dead cable when ejection happens.
It is simple and uses standard 3 core flex.
Highly reliable and very available, it is a long established system that really works very well indeed. In UK it is fitted to nearly all NHS A&E ambulances, large numbers of fire engines and police vehicles, as well as M.O.D. and other vehicles.
We make 3 versions, available at 110 volts, 230 volts and 400 volts, in 15 and 32 amp connector sizes.