7 ms·

> “If we increase the voltage on the car side then we can reduce the current we need to push through the cable….so we are looking at higher voltage drivetrains,

> “If we increase the voltage on the car side then we can reduce the current we need to push through the cable….so we are looking at higher voltage drivetrains,” says Elshout. Presumably connect the batteries in series rather than parallel, so that the voltage is increased and the current is lessened

londons_explore 7y ago
It isn't unreasonable to have a battery which can reconfigure itself. It could switch from parallel to series just by opening and closing a few relays.
mdorazio 7y ago
I'm thinking this would probably greatly increase the chance of arcing and catastrophic battery failures in the cell packs, but I'm not certain on that. Also, you still need to get that power into something useful for the rest of the car now - usually 12V for electronics and probably 350ish volts AC for the motor, so you're still going to need to deal with the conversions at some point. There's a reason high-voltage lines are nowhere near people and transformers are chunky as hell. Probably those reasons overlap with EV design constraints.
- AWildC182 7y ago
  It's entirely doable. Tesla packs are already close to 400V and it's totally possible to go much higher. Keep in mind that every battery is a resistor so the voltage across each one is still tiny, even if the overall series voltage is massive. The reason power transmission equipment looks so weird is A) because it handles 345,000V and B) we have a lot of it and the chunky transformers and bare, massively spaced out conductors are way cheaper than wrapping everything in teflon. Also, pretty much all EVs have a 12v lead acid cell somewhere. It's kinda dumb but it's the cheapest solution to having 12v for relevant systems. The pack/charger voltage is stepped down to charge them.
  - greglindahl 7y ago
    Remember that OP said 10k volts. 400 isn't close to that. For all the "move fast and break things" of Tesla, they haven't moved fast and electrocuted people with a 10k volt battery system.

londons_explore 7y ago

It isn't unreasonable to have a battery which can reconfigure itself. It could switch from parallel to series just by opening and closing a few relays.

mdorazio 7y ago

I'm thinking this would probably greatly increase the chance of arcing and catastrophic battery failures in the cell packs, but I'm not certain on that. Also, you still need to get that power into something useful for the rest of the car now - usually 12V for electronics and probably 350ish volts AC for the motor, so you're still going to need to deal with the conversions at some point. There's a reason high-voltage lines are nowhere near people and transformers are chunky as hell. Probably those reasons overlap with EV design constraints.

AWildC182 7y ago
It's entirely doable. Tesla packs are already close to 400V and it's totally possible to go much higher. Keep in mind that every battery is a resistor so the voltage across each one is still tiny, even if the overall series voltage is massive. The reason power transmission equipment looks so weird is A) because it handles 345,000V and B) we have a lot of it and the chunky transformers and bare, massively spaced out conductors are way cheaper than wrapping everything in teflon. Also, pretty much all EVs have a 12v lead acid cell somewhere. It's kinda dumb but it's the cheapest solution to having 12v for relevant systems. The pack/charger voltage is stepped down to charge them.
- greglindahl 7y ago
  Remember that OP said 10k volts. 400 isn't close to that. For all the "move fast and break things" of Tesla, they haven't moved fast and electrocuted people with a 10k volt battery system.