this post was submitted on 26 Jul 2024
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[–] [email protected] 29 points 3 months ago* (last edited 3 months ago) (6 children)

For a smaller EV It would take around 200kWh worth of battery for a 600 mile range. The current Tesla "superchargers" put out 250kWh. So whatever is going to charge this battery will have to output roughly an order of magnitude more power in order to charge the battery in 6 minutes. That's an impressive and scary amount of energy transfer.

Edit: I don't know where I got 6 minutes from. So not quite 10X the power for charging, but a LOT more than current chargers.

[–] [email protected] 58 points 3 months ago (1 children)

A couple things: solid state batteries weigh much less. Solid state batteries are 30-50% lighter per kWh. The initial ones will probably be closer to 30% lighter. A 100 kWh battery weighs about 1400 lbs (635 kg). Shaving off 400 lbs is pretty significant and results in much better range for the same battery capacity. The battery pack is likely closer to 150 kWh.

Second thing would be the charge rate. Yes, a supercharger can 250 kW output (not kWh BTW) but a few factors means that they often do not. First thing would be heat. If the charging cable or the battery gets too hot, the the rate slows down. The next thing would be the fact that current batteries have to start at a slow rate and end at a slow rate. Solid state batteries do not have those issue nearly as much and can more consistently hit that 250 kW output for a longer period of time.

This thing, they are likely using 350+ kW chargers. Higher than 350 kW is pretty rare but the odd 400 kW and 450 kW charger does exist.

And doing some more digging, I found that it is from 8% to 80% in 9 minutes. And even then, it does not say it is the same 150 kWh battery that is being charged that fast. This could be marketing crap where it is giving numbers for a ~85 kWh battery to compare it to EVs today. An Ioniq 5 takes about twice as long to go from 10-80% at 350 kW.

[–] [email protected] 7 points 3 months ago

Super informative, thanks :)

[–] [email protected] 29 points 3 months ago

The current Tesla "superchargers" put out 250kWh

kW

My wall outlet charger puts out 250 kWh, if you leave it in for 2 weeks straight...

[–] [email protected] 8 points 3 months ago

So each supercharger will need it's own miniature fusion power plant. Great, now fast charging solid state batteries will always be 30 years away.

[–] [email protected] 6 points 3 months ago

Yes, Teslas can charge at 250 kW, but they do not sustain that charging rate for long. As the battery charges, its charging rate drops. If newer battery technologies can sustain the higher charge rates longer, they could theoretically store more charge in less time.

[–] [email protected] 5 points 3 months ago (1 children)

This is the big reason why solid state batteries aren't an EV miracle. Pack density and charging speeds these days are already limited by cooling capacity. Trying to pump a few MW of power into a battery pack to get 600 miles in 9 minutes is going to melt the car, or require lugging around a huge cooling system.

[–] [email protected] 4 points 3 months ago (1 children)

Standardized interchangeable batteries would be neat. Pull into a battery station, a machine swaps out your packs and you're on your way faster than a fill-up.

[–] [email protected] 1 points 3 months ago

That was one of the original tesla quick"charge" concepts. You'd drive over a pit like oil stops and it situs swap out your battery for a charged one

[–] [email protected] 2 points 3 months ago* (last edited 3 months ago)

EE here. Chargers put out power in units of kW, while batteries store energy in units of kWh or MJ or what have you. Otherwise, you're absolutely correct.

Typically Distributed Generation (DG) scale solar PV and battery storage sites are sized anywhere from 1 to 10 MW.

At 1 MW, you could run (1) charger at a speed of 1 MW, or (2) at 500 kW, etc. Usually need just (1) transformer for that size installation too.

At 10 MW, you can run each charger at 1 MW or so, but you're also talking about probably (4-10) transformers @ $250k USD a pop. Installation prices go up the more you demand in power transfer.

Then you need to consider that most DG projects need to pay for the upgrades to their downstream grid architecture, meaning reconducting or upsizing cable, breakers, switches, transformers, reactors, sensors, relays, etc.

Not saying it's impossible. You could co-locate and DC-couple solar PV or Wind parks next to charging points to get around some of the grid upgrades, but most people live in areas that require homes and grocery stores and other buildings than flat land meant for solar PV or Wind.

When it comes down to it, it's so much easier to just trickle charge your EV at night via arbitrage and when you're sleeping so all of this infrastructure doesn't have to been upgraded - and I'd argue upgraded needlessly because we need to save that copper and iron and materials for upgrades to the parts of the grid meant to interconnect renewables.

But there is no silver bullet to these things so we'll likely see more, larger chargers come through unless regulators stop it from happening.