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I'm having trouble understanding from the article how do these chips help with faster charging/longer range? Saw the hackaday article but that doesn't really ex

I'm having trouble understanding from the article how do these chips help with faster charging/longer range? Saw the hackaday article but that doesn't really explain it either

BostonEnginerd 5y ago
Because silicon carbide has a wide band gap, you can use it to switch higher voltages. This means lower current losses through wiring. It also can operate at higher temperatures more effectively, so it can be driven harder than a silicon transistor.
_ph_ 5y ago
The idea is, to minimize losses in the power electronics. That should give a bit of range increase (but not too much) but mostly It reduces the heat produced while operating. So they can be smaller, need less cooling. Being smaller helps with production costs, as wafer space is the main cost driver.
raverbashing 5y ago
You can work with higher voltages, at higher frequencies (also faster switching speeds). All this mean lower losses (= higher efficiency)
zbrozek 5y ago
It's a pretty incremental and small opportunity, but one worth seizing nonetheless. SiC devices have a better figure of merit (Qg * Rds) at high voltages than Si devices. The lower gate charge (Qg) means you can switch them more quickly, spending less time transitioning between fully-on and fully-off (where the device is inefficient). And the lower drain-to-source resistance (Rds) means that when fully-on it's generating less heat as well. In a motor controller you will probably bank that as an efficiency improvement, probably on the order of 1-2% at cruise and maybe a bit more during heavy acceleration or deceleration. In a charger you will probably change your optimization to reduce its size and weight for a given power delivery capability. In case that's on onboard charger, that means you haul around less weight and further improve vehicle efficiency a bit. That improved figure of merit also reduces the cost of having more power handling capability, which is how it might incrementally speed up charging. To my mind, the biggest thing we can do to improve cars generally is to figure out how to reduce their weight. It's not obvious how to do that without either cutting back on passive safety or dramatically driving up the structural cost (e.g., with metallic foams for energy absorption in crashes).
- ec109685 5y ago
  With Tesla Super Chargers, it delivers DC to the car, so the onboard charger is bypassed, so it doesn’t do much for saving space there.
cmrdporcupine 5y ago
Not An EE, But(tm): A lot of engineering in electric vehicles is in managing the heat in the high voltage electronics. These transistors could be used in the traction inverter and the charging systems to get better efficiency and higher heat tolerance. If you open up an electric motor controller you'll find it's full of MOSFETs, and they get really hot the harder you push them. The ones in EVs usually have liquid cooling and/or fans and lots of heat sinks. So with this chemistry it sounds like less energy spent cooling, and more energy spent driving or charging. Also sounds like they're more efficient at higher voltages in general. So again, more range or more power, or both.

I'm having trouble understanding from the article how do these chips help with faster charging/longer range? Saw the hackaday article but that doesn't really explain it either

BostonEnginerd 5y ago

Because silicon carbide has a wide band gap, you can use it to switch higher voltages. This means lower current losses through wiring. It also can operate at higher temperatures more effectively, so it can be driven harder than a silicon transistor.

_ph_ 5y ago

The idea is, to minimize losses in the power electronics. That should give a bit of range increase (but not too much) but mostly It reduces the heat produced while operating. So they can be smaller, need less cooling. Being smaller helps with production costs, as wafer space is the main cost driver.

raverbashing 5y ago

You can work with higher voltages, at higher frequencies (also faster switching speeds). All this mean lower losses (= higher efficiency)

zbrozek 5y ago

It's a pretty incremental and small opportunity, but one worth seizing nonetheless. SiC devices have a better figure of merit (Qg * Rds) at high voltages than Si devices. The lower gate charge (Qg) means you can switch them more quickly, spending less time transitioning between fully-on and fully-off (where the device is inefficient). And the lower drain-to-source resistance (Rds) means that when fully-on it's generating less heat as well. In a motor controller you will probably bank that as an efficiency improvement, probably on the order of 1-2% at cruise and maybe a bit more during heavy acceleration or deceleration. In a charger you will probably change your optimization to reduce its size and weight for a given power delivery capability. In case that's on onboard charger, that means you haul around less weight and further improve vehicle efficiency a bit. That improved figure of merit also reduces the cost of having more power handling capability, which is how it might incrementally speed up charging. To my mind, the biggest thing we can do to improve cars generally is to figure out how to reduce their weight. It's not obvious how to do that without either cutting back on passive safety or dramatically driving up the structural cost (e.g., with metallic foams for energy absorption in crashes).

ec109685 5y ago
With Tesla Super Chargers, it delivers DC to the car, so the onboard charger is bypassed, so it doesn’t do much for saving space there.

cmrdporcupine 5y ago

Not An EE, But(tm): A lot of engineering in electric vehicles is in managing the heat in the high voltage electronics. These transistors could be used in the traction inverter and the charging systems to get better efficiency and higher heat tolerance. If you open up an electric motor controller you'll find it's full of MOSFETs, and they get really hot the harder you push them. The ones in EVs usually have liquid cooling and/or fans and lots of heat sinks. So with this chemistry it sounds like less energy spent cooling, and more energy spent driving or charging. Also sounds like they're more efficient at higher voltages in general. So again, more range or more power, or both.