5 ms·

Going on nine_k's answer, at 600V you'd also need a charging cable to handle 1200A. That's so thick (~50mm) a 3m cable's going to weigh 52KG. I'm sure somebody

Going on nine_k's answer, at 600V you'd also need a charging cable to handle 1200A. That's so thick (~50mm) a 3m cable's going to weigh 52KG. I'm sure somebody will jump in and suggest an alternative. Let's just put 10kV through the car. Then it's only 72A. Nothing bad happens at 10kV. Burst-chargers are silly. They might work, they might not, but either way they present such immediate problems for mass deployment that they should be considered a distraction. What we need today is "little" 10-15KWh replaceable battery pods. We're still talking up to 80KG, but something to get you 50 miles. These could be cycled out, cool-charged and essentially offer unlimited range to anyone without adding significant delay. You could also lower the onboard cost of new cars by reducing the standard battery size. I want a Tesla, but I need about 20 miles range for 99% of the time. Buying a 15KW battery and hiring the extra would be a better solution for me.

rcxdude 4y ago
Existing fast chargers can do 600A, the main trick is they water-cool the cable, which substantially reduces the amount of copper you need. They're about as difficult to handle as a gas pump nozzle. Somehow shifting 80kg batteries in and out of your car seems a lot harder to manage.
- oliwarner 4y ago
  > shifting 80kg batteries The cool thing about these batteries is they're made up of small cells. 8×10Kg units could be swapped out with relative ease. Or we belt-feed 18650s and eject spent ones like a minigin. Cooler but harder to handle the electrics.
jimmcslim 4y ago
Better Place tried the whole replaceable battery pack idea... https://en.wikipedia.org/wiki/Better_Place_(company) https://en.wikipedia.org/wiki/Better_Place_(company) Switching batteries sounds like a good idea to me, but it doesn't seem to scale to this level .
- clouddrover 4y ago
  NIO has built its EV batteries to be swappable. You can switch between different capacities as needed: https://insideevs.com/news/581626/china-nio-900-battery-swap-stations/ https://insideevs.com/news/581626/china-nio-900-battery-swap... https://insideevs.com/news/591837/nio-battery-swapping-station-norway-5-minutes/ https://insideevs.com/news/591837/nio-battery-swapping-stati...
- oliwarner 4y ago
  You need scale. Swap stations need to exist every 20 miles on major roads (like combustible fuels) and for that you need customers. How many EVs were there in 2007-2013? Today's problems are charge speed, range and cost. Swappable batteries would solve all three, without needing lN2-cooled charging cables, needing to dissipate 7.2KW of deep internal heat, at standstill, no less. Whatever the physical realities or economics, we should be mandating a common power input framework so that this is possible for today's cars tomorrow.
  - bcrl 4y ago
    I don't think the main battery pack needs to be swappable, but there needs to be a common standard for a secondary battery pack (like boosting a car to start it today). There's lots of space in the frunk of an electric car for the owner to drop in a portable battery back when the extra range is needed. Alcan (the aluminimum manufacturer) demonstrated a non-rechargable (but recyclable) aluminium-air battery a few years back that could be swapped and provide 1000 km of range. The lack of a "jerry can" solution for electric cars today seems... shortsighted. The really good thing about electric cars is that once the platform is in place it becomes almost trivial to use alternative sources of electricity to provide the power the car needs or charge the battery. Methanol fuel cell are finally on the market and while currently expensive, can be refueled with the same convenience as existing fossil fuel based ICEs. The future of electric cars is indeed a promising one.
hathawsh 4y ago
As pointed out on the recent Technology Connections YouTube video, EV charging cables are often liquid cooled so they can push extra current through a relatively lightweight cable. (I thought that was a pretty cool innovation.)
clouddrover 4y ago
You don't need to charge it at its maximum rate. Even making full use of existing 350 and 400 kW chargers will be useful. The current CCS specification goes to 500 kW. The Megawatt Charging System is the next step up: https://www.charin.global/technology/mcs/ https://www.charin.global/technology/mcs/ https://en.wikipedia.org/wiki/Megawatt_Charging_System https://en.wikipedia.org/wiki/Megawatt_Charging_System

rcxdude 4y ago

Existing fast chargers can do 600A, the main trick is they water-cool the cable, which substantially reduces the amount of copper you need. They're about as difficult to handle as a gas pump nozzle. Somehow shifting 80kg batteries in and out of your car seems a lot harder to manage.

oliwarner 4y ago
> shifting 80kg batteries The cool thing about these batteries is they're made up of small cells. 8×10Kg units could be swapped out with relative ease. Or we belt-feed 18650s and eject spent ones like a minigin. Cooler but harder to handle the electrics.

jimmcslim 4y ago

Better Place tried the whole replaceable battery pack idea... https://en.wikipedia.org/wiki/Better_Place_(company) https://en.wikipedia.org/wiki/Better_Place_(company) Switching batteries sounds like a good idea to me, but it doesn't seem to scale to this level .

clouddrover 4y ago
NIO has built its EV batteries to be swappable. You can switch between different capacities as needed: https://insideevs.com/news/581626/china-nio-900-battery-swap-stations/ https://insideevs.com/news/581626/china-nio-900-battery-swap... https://insideevs.com/news/591837/nio-battery-swapping-station-norway-5-minutes/ https://insideevs.com/news/591837/nio-battery-swapping-stati...
oliwarner 4y ago
You need scale. Swap stations need to exist every 20 miles on major roads (like combustible fuels) and for that you need customers. How many EVs were there in 2007-2013? Today's problems are charge speed, range and cost. Swappable batteries would solve all three, without needing lN2-cooled charging cables, needing to dissipate 7.2KW of deep internal heat, at standstill, no less. Whatever the physical realities or economics, we should be mandating a common power input framework so that this is possible for today's cars tomorrow.
- bcrl 4y ago
  I don't think the main battery pack needs to be swappable, but there needs to be a common standard for a secondary battery pack (like boosting a car to start it today). There's lots of space in the frunk of an electric car for the owner to drop in a portable battery back when the extra range is needed. Alcan (the aluminimum manufacturer) demonstrated a non-rechargable (but recyclable) aluminium-air battery a few years back that could be swapped and provide 1000 km of range. The lack of a "jerry can" solution for electric cars today seems... shortsighted. The really good thing about electric cars is that once the platform is in place it becomes almost trivial to use alternative sources of electricity to provide the power the car needs or charge the battery. Methanol fuel cell are finally on the market and while currently expensive, can be refueled with the same convenience as existing fossil fuel based ICEs. The future of electric cars is indeed a promising one.

hathawsh 4y ago

As pointed out on the recent Technology Connections YouTube video, EV charging cables are often liquid cooled so they can push extra current through a relatively lightweight cable. (I thought that was a pretty cool innovation.)

clouddrover 4y ago

You don't need to charge it at its maximum rate. Even making full use of existing 350 and 400 kW chargers will be useful. The current CCS specification goes to 500 kW. The Megawatt Charging System is the next step up: https://www.charin.global/technology/mcs/ https://www.charin.global/technology/mcs/ https://en.wikipedia.org/wiki/Megawatt_Charging_System https://en.wikipedia.org/wiki/Megawatt_Charging_System