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Jason_Batemans_Hair t1_is1neey wrote

Reply to comment by pseudopad in A breakthrough in electric vehicle battery design has enabled a 10-minute charge time for a typical EV battery. The record-breaking combination of a shorter charge time and more energy acquired for longer travel range was announced today by Wagamaga

Correct, and the best way to tackle that problem doesn't seem to have been worked out.

I wonder if having a large supercapacitor as part of each public charger might allow for a feasible solution. The supercapacitor's charge time could be much longer than 10 minutes, but its high discharge rate could then allow for fast charging of a vehicle.

Not my field, so feel free to laugh if this is implausible. How large would a supercapacitor have to be to store 100 kWh?

edit: copied from below

100 kWh in 10 minutes would mean 600 kW supply per charger.

A standard house service provides 24 kW, so each charger would have to supply equivalent power to 25 houses. Let's assume a charging lot has 10 chargers - that's 250 houses equivalent in one small location (6 MW), corresponding to one 'gas' station.

A little searching seems to show the Tesla V3 charging locations have 8 stalls at 250 kW each, or 2 MW per location - and even these don't exist in most of the country. Sorry for trying to help.

edit2: That house equivalence is way off since groups of houses aren't pulling max load all the time. 6 MW should service much more than 250 houses. (600 homes per 1 MW is commonly cited, so ~3600 homes)

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tdrhq t1_is3dsbe wrote

As I mentioned in another comment, heat generated in a wire is a function of amperage not power being transferred. That's how high-voltage power lines can transfer energy to power entire cities.

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Jason_Batemans_Hair t1_is3mk3i wrote

Right, hopefully most people here know that. I hope most people here also know that in terms of existing infrastructure, gas station locations are virtually all secondary customers, not primary customers.

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perrochon t1_is1sg7c wrote

The limit is on the EV battery side. How much can it take...

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Jason_Batemans_Hair t1_is2d740 wrote

No, that's not the issue here.

As the commenter above correctly pointed out, we don't generally have transmission infrastructure in place to supply the current necessary for fast charging.

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perrochon t1_is2dk6h wrote

But we do in most places where people would charge :-) we have plenty of chargers that can charge cars at many MW combined. Some have battery backup. 10MW+ is not a problem. Charging 50 cars is not a problem.

And we will deploy more where we need more.

Maybe capacitors play a role some when, somewhere, but it's not required.

Right now a simple 250kW+ charger will have to slow down because of the car battery heating up....

Tesla V3 could charge at 300kW, and there are dozens per location. They limit to 250kW because of the car. And they are 400V. There are 800V stations that can easily do more.

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Jason_Batemans_Hair t1_is2iuzo wrote

100 kWh in 10 minutes would mean 600 kW supply per charger.

A standard house service provides 24 kW, so each charger would have to supply equivalent power to 25 houses. Let's assume a charging lot has 10 chargers - that's 250 houses equivalent in one small location (6 MW), corresponding to one 'gas' station.

Where are you seeing this commonly existing? Do you have a link to a map of these?

edit:

I see you edited your comment without answering my question. Oh well. A little searching seems to show the Tesla V3 charging locations have 8 stalls at 250 kW each, or 2 MW per location - and even these don't exist in most of the country. Sorry for trying to help.

edit2:

The largest sedan battery pack Tesla currently offers is 100 kWh, so I sized for that.

The issue here isn't so much about kWh, but kW. Charge rate, i.e. time spent charging on a trip, seems to be a commonly cited operational obstacle causing so many to keep buying ICE vehicles. People don't want to have to charge for an hour or more every 200-300 miles.

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perrochon t1_is2wgz3 wrote

https://www.tesla.com/findus/location/supercharger/firebaughsupercharger

Has 56 stalls. Middle of nowhere.

Harris Ranch may go to almost 100.

Baker, CA has CCS right next to it.

Every new supercharger has been V3 for a while. V4 is coming out soon.

We don't need those in residential areas where people charge at home and slowly. It's not like the residential gas station that people feel up now for their weekly driving. We need those a long major traffic routes. Maybe in some areas with lots of apartments.

Most new houses in the US had 200 amps at 240V for years. That is some 40 kilowatts.

You have to look for industrial sized electricity. Not residential. This is an industrial hookup.

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Jason_Batemans_Hair t1_is325c8 wrote

Anyone looking at the map of Tesla chargers can see that my comment represented the situation fairly, whereas you found 1 oddball charging site in the entire United States and present that as if it's relevant - and it's still just 250 kW chargers anyway. That's intellectually dishonest IMO.

You have a strange agenda, to be arguing with people who would like to see more electrification. There's no good reason for you to be misrepresenting the state of affairs.

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Deafcat22 t1_is338kz wrote

You might be confusing combined theoretical peak loads with working demand loads in the real world.

Actual electric cars don't have 100 kWh packs, for starters. Most people are fine with half of that, 50kWh.

Also, very few people go to fast chargers with a 0% battery state. Most people also don't leave the fast charger with 100% battery state. In practice, it's more common to assume most drivers will charge 50% of the battery capacity, which for the sake of argument let's say is 25kWh.

Finally, the actual fast charge rate is proportionate to how close to empty the battery pack is.. a Tesla at 25% SOC topping up to 75% SOC might only start the charge at 100-150kW, tapering down below 50kW.

Yes, a very busy supercharging station in a dense city needs a fair bit of power (and may "peak shave" actual grid demand with on-site battery storage). For most cities however, it's actually not a huge load in practice, and easily implemented (which is why so many cities around the world have already installed them, even cities below 300,000 population like mine).

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