I've been thinking for a while about all the promises from Fisker and other (future) EV manufacturers about a 1min charging time. Not that much about the vehicles themselves or their batteries, but the infrastructure required to do that. Let's do some assumptions:
200Wh/m (very optimistic efficiency - assuming groundbreaking in aerodynamics, tires, etc)
300miles range - that's what they usually promise
So the battery should be able to discharge at least 200*300=60KWh
To simplify let's use an ideal case - there are no losses in the charger, battery chargers from 0 to 100% in a linear manner. Or the battery is 100KWh, but it's only used between 20-80% that's not relevant. The bottom line is you have to transfer 60KWh to the car in 1min. If it was 1h it is easy math - 60KW for 1hour (that is 600V, 100A - very reasonable). Now if you want to transfer 60KWh in 1min it would be 60 times more - 3600KW=3.6MW
I am not sure what are the requirements for high voltage insulation, but my bet is no manufacturer would go more than a 1000V system (it will probably be DC, otherwise you should carry some solid charger in your trunk). That means the current would be 3600KW/1KV = 3600A. For reference if voltage is 10KV, current would be 360A
I am not in a close touch with latest tech in high power transfer, but one way to go is using multiple conductors, another way would be some kind of magnetic conversion - you park above a plate that lifts close to the battery and does some magic to transfer 60KWh in 1min...
Any ideas? Or maybe you have read more info on the subject somewhere else? Do you care to share?
Thanks
200Wh/m (very optimistic efficiency - assuming groundbreaking in aerodynamics, tires, etc)
300miles range - that's what they usually promise
So the battery should be able to discharge at least 200*300=60KWh
To simplify let's use an ideal case - there are no losses in the charger, battery chargers from 0 to 100% in a linear manner. Or the battery is 100KWh, but it's only used between 20-80% that's not relevant. The bottom line is you have to transfer 60KWh to the car in 1min. If it was 1h it is easy math - 60KW for 1hour (that is 600V, 100A - very reasonable). Now if you want to transfer 60KWh in 1min it would be 60 times more - 3600KW=3.6MW
I am not sure what are the requirements for high voltage insulation, but my bet is no manufacturer would go more than a 1000V system (it will probably be DC, otherwise you should carry some solid charger in your trunk). That means the current would be 3600KW/1KV = 3600A. For reference if voltage is 10KV, current would be 360A
I am not in a close touch with latest tech in high power transfer, but one way to go is using multiple conductors, another way would be some kind of magnetic conversion - you park above a plate that lifts close to the battery and does some magic to transfer 60KWh in 1min...
Any ideas? Or maybe you have read more info on the subject somewhere else? Do you care to share?
Thanks