5 ms·

You could easily imagine an EV with a hybrid battery pack consisting of 2/3 Li-Ion and 1/3 Al-Ion. You pay very little in range for the combination compared to

You could easily imagine an EV with a hybrid battery pack consisting of 2/3 Li-Ion and 1/3 Al-Ion. You pay very little in range for the combination compared to a Li_Ion pack, but you gain flexibility. You then discharge the Al-Ion part of the pack first, partly because it has better longevity across cycles, but mostly because this then lets you charge that empty third of the pack very quickly giving enough range for an extra hour or two of driving.

adrianN 5y ago
Delivering that much power seems pretty difficult to me. EVs already charge at dozens of kW. How high do you have to make the voltages to keep the cables a reasonable diameter when you want to charge in the Megawatt range?
- peteradio 5y ago
  Sounds crappy but what if faster charging ends up being accomplished with more cords and more charging ports? Want double charging rate? Plug in two cords.
  - ajcp 5y ago
    I can see this as something that is included in upgraded trims. Mid-level trim = two charging ports. Premium trim = 3! $$$
  - anonAndOn 5y ago
    You could definitely increase the ampacity if each charging cord was only one wire. Perhaps that's the key to quick recharges?
    - sly010 5y ago
      Also gives you something to do, while you are waiting. By the time you plugged in the 5th wire, the first 4 charged you halfway :D
- extrapickles 5y ago
  If you assume that 500A is the largest cable that a user can handle[0], then 2kV per megawatt. If you don't mind actively cooling the part of the cable the user handles, then you could run at higher currents for the same cable size. The biggest problem likely will be the much higher demand charges from the power company (they really don't like sudden large loads), so the charging station will likely need a large battery pack of its own. [0]: You want injured/elderly people to be able to charge without assistance so cable weight/stiffness is a important design factor.
- Dylan16807 5y ago
  They're already working on deploying 350kW 500 amp charging stations. That's about 5 minutes to get 100 miles, and the cables are a bit awkward but not too bad. And 500kW 500 amp is easily accomplished on the same standards. Also keep an eye on potential 2-3 megawatt plugs for trucks.
- Reason077 5y ago
  A "Megawatt Charging System" (MCS) is already in development for charging heavy commercial vehicles and aircraft. It's designed to scale up to 3000 A at 1500 V. https://en.wikipedia.org/wiki/Megawatt_Charging_System https://en.wikipedia.org/wiki/Megawatt_Charging_System
m463 5y ago
I've always thought it should go the other way. Add a supercapacitor. This would allow bursts of extreme power, along with stronger regenerative braking with full capture of energy. I think the racetrack would be a great use case.
- londons_explore 5y ago
  Last I looked, supercapacitors just aren't quite high up enough on the volume/energy curve. Getting rid of a few batteries to make space for a few supercaps so you can regen quickly when emergency stopping sounds great, but then you realise it can only capture a tiny portion of the cars energy at 70 mph unless you replace nearly all the cars battery.

adrianN 5y ago

Delivering that much power seems pretty difficult to me. EVs already charge at dozens of kW. How high do you have to make the voltages to keep the cables a reasonable diameter when you want to charge in the Megawatt range?

peteradio 5y ago
Sounds crappy but what if faster charging ends up being accomplished with more cords and more charging ports? Want double charging rate? Plug in two cords.
- ajcp 5y ago
  I can see this as something that is included in upgraded trims. Mid-level trim = two charging ports. Premium trim = 3! $$$
- anonAndOn 5y ago
  You could definitely increase the ampacity if each charging cord was only one wire. Perhaps that's the key to quick recharges?
  - sly010 5y ago
    Also gives you something to do, while you are waiting. By the time you plugged in the 5th wire, the first 4 charged you halfway :D
extrapickles 5y ago
If you assume that 500A is the largest cable that a user can handle[0], then 2kV per megawatt. If you don't mind actively cooling the part of the cable the user handles, then you could run at higher currents for the same cable size. The biggest problem likely will be the much higher demand charges from the power company (they really don't like sudden large loads), so the charging station will likely need a large battery pack of its own. [0]: You want injured/elderly people to be able to charge without assistance so cable weight/stiffness is a important design factor.
Dylan16807 5y ago
They're already working on deploying 350kW 500 amp charging stations. That's about 5 minutes to get 100 miles, and the cables are a bit awkward but not too bad. And 500kW 500 amp is easily accomplished on the same standards. Also keep an eye on potential 2-3 megawatt plugs for trucks.
Reason077 5y ago
A "Megawatt Charging System" (MCS) is already in development for charging heavy commercial vehicles and aircraft. It's designed to scale up to 3000 A at 1500 V. https://en.wikipedia.org/wiki/Megawatt_Charging_System https://en.wikipedia.org/wiki/Megawatt_Charging_System

m463 5y ago

I've always thought it should go the other way. Add a supercapacitor. This would allow bursts of extreme power, along with stronger regenerative braking with full capture of energy. I think the racetrack would be a great use case.

londons_explore 5y ago
Last I looked, supercapacitors just aren't quite high up enough on the volume/energy curve. Getting rid of a few batteries to make space for a few supercaps so you can regen quickly when emergency stopping sounds great, but then you realise it can only capture a tiny portion of the cars energy at 70 mph unless you replace nearly all the cars battery.