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Comment by Animats | Hacker News Reader

It's just getting started. Solid state batteries are getting close. There are big companies, from Toyota on down, putting together manufacturing facilities. Nio is already shipping an early semi-solid-state battery.

The solid state battery era looks like this:

- Much better safety. No thermal runaway problem. Survives nail test.

- Upwards of 5,000 charge cycles.

- Charge times around 5 minutes.

- Maybe better energy density.

- Cost not yet well understood. Manufacturing is hard.

For small devices, the battery should outlive the device.

For cars, the usage model looks more like gas cars. Drive 300-400 miles, recharge in 5-10 minutes. This has land-use implications. Gas stations can convert to charging stations in the same footprint and layout. No need for giant parking lots of chargers.

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Supermarkets and small malls might take over the charging locations as they already have plenty of parking space.

Only reason for gas stations to be a seperate type of shop is how expensive and dangeous it is to have a gasoline pipes to every parking space. This is easy and cheap to do for electricity.

To bring in more revenue many gas stations try to be a "bit of a supermarket" in addition to selling gas. With electricity it will likely go the other way around, so supermarkets will extend with selling electricity and there will less reason to have gas stations as a seperate business location.

I already see supermarkets here getting a few charging spaces, usually a bit in the back.

Most of the DCFC's I've used were in Walmart parking lots.

While the land use might not change the electricity requirement will change dramatically! To the point I'm not sure if it is economically feasible to convert a liquid fuel station.

Maybe the new 'hot' sites for such will be next to grid substations.

Could existing substations even come close to that kind of load? 8 cars recharging at MW rates would saturate most substation transformers in my area.

Perhaps installing a big battery bank that trickle charges would smooth the load.

How many MWs would a carpark roofed with solar panels generate? My calculations say you need about 4k square meters to get 1MW whilst the sun is shining bright. That's about the size of medium sized supermarket carpark. Double that if you cover the building as well. You might get a good 2MW at peak, enough to allow a few cars charging at once. Not much good at after the afternoon sun has gone down and the after work rush is happening at the supermarket.

Given most drivers will be charging at home, I wonder what percentage of cars we can expect to be wanting to charge whilst shopping?

Many DCFC car charges already use batteries so as to avoid more expensive service links while still providing rapid charging.

Is that true? If so, that's extremely interesting. However, for popular chargers, it seems unlikely to help pay the first charge of the day.

There is no "first charge of the day". The only first charge is the one following a power failure of the grid. During billing rollover, the charger's battery is powered up from yesterday's power.

That was a typo. Replace "pay" with "past".

Unless you have enormous battery banks, the first few charges will deplete them.

the cost thing seems pretty crucial. if room-temperature solid-electrolyte batteries end up costing ten times as much as lithium-ion batteries per joule, they'll remain a niche technology, though potentially one that's used in every cellphone, like tantalum capacitors. if they end up being one tenth the cost of lithium-ion batteries, indeed, it's just getting started. can we even confidently bound the ultimate cost to within that interval?

Cost is a big problem. Some sources say 3x to 4x the cost of lithium-ion batteries, at least initially. Nissan and Toyota both claim manufacturing cost breakthroughs. Apparently this is hard to do, but not a raw materials problem.

Lithium-iron-phosphate batteries have taken over the low end of the market. Cheaper and safer, but less energy per kilogram.

> Some sources say 3x to 4x the cost of lithium-ion batteries, at least initially.

If that's true, that's miraculous. Given the order of magnitude reduction that will come with economies of scale and commercialisation (as we've experienced with Li-ion), they'll be cheaper than Li-ion in no time.

I bet I saw the exact same thing about 14 years ago.

The bottleneck for charging hasn't been the battery for a while, because we're already at the point where we could hook up multiple chargers for better performance. The bottleneck is in electricity as an energy vector, because someone either needs to start generating several MW per car, which is expensive, or be curtailing the same amount, which is wasteful.

Gas stations could even double as charging stations as well and serve both groups if charging could be done in 5 mins.

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