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Comment by elihu | Hacker News Reader

> By weight, it offers between 380-500 Wh/kg, as compared to 260 Wh/kg in packages currently used by Tesla.

That's pretty huge if the company's claims hold up. That's in the ballpark where doing an EV conversion on an existing ICE car becomes a lot easier because you could theoretically just replace the original gas tank with 100-200 pounds of batteries and have a good-enough range to be useful for short/medium trips. And the car might end up lighter than stock.

I wonder what the material inputs are? Does this battery use cobalt or nickel or anything else that's similarly expensive? Or can these things in theory be made super cheap once the manufacturing scales up?

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This would also be amazing for electric aircraft, as capacity to weight ratio is the main thing holding them back.

It would. Liquid fuels would still have an enormous energy storage to weight ratio advantage, but electric aircraft might become good enough to be practically useful.

I'd imagine there could be military applications too, once the energy density is high enough to be useful. If you have, say, a bunch of tanks that can run off of diesel or batteries, then you can recharge them opportunistically whenever power is available (i.e. if you're defending a city that still has functioning utilities) and save the diesel for when you have to move long distances. Basically, it makes the fuel resupply logistics more flexible, and it reduces costs and climate impact in peacetime if exercises are conducted mainly on batteries.

I think the biggest advantage would be that you wouldn't show up so much on thermovison cameras, since ICEs create so much excess heat.

Reliable utility electricity in a war zone seems unlikely. Though big 'ol power plants make pretty easy and tempting targets (especially if you know your opponent relies on it to drive their vehicles).

This would be a great use case for space-based microwave solar though (if it ever gets off the ground).

...ackshually: https://twitter.com/t1heikkila/status/1524092117622169604

Odessa in Ukraine doesn't have gasoline or diesel. They do have electricity though and people with EVs are driving around just fine - even an electric Taxi.

Gasoline distribution points (gas stations) tend to also blow up in a pretty ball of fire when attacked.

An EV can be charged from any socket with working power.

Then clouds/a thunderstorm hits and all your tanks die due to lack of power

Fuel supply lines are a big thing in modern warfare. You can chart most of the big tactical moves in WW2 as being about control of fuel supplies.

https://en.m.wikipedia.org/wiki/Oil_campaign_of_World_War_II

which is probably part of the reason the US Army is so big on renewables.

And Japan mostly went to war over oil.

Automated Transport Gliders: Have a blended Wing with Containers, a few of them Batterys, they circle up, fly toward their destination, Land, Replace with Recharged and Go back. Slow, but nearly no downtime and thus interesting.

This is incorrect, well, partially. The main issue holding back electric aircraft is volumetric efficiency (space), not weight.

Jet fuels for take off (and maybe landing) and electric for sustaining flight once in the air?

> capacity to weight ratio

AKA "specific energy", usually measured in kWh/kg or MJ/kg.

Small two-seaters maybe. Or slightly bigger aircrafts doing short hops (e.g. island hopping). This is still nowhere near close anything that could be used on big commercial planes.

LFP will hit 260 wh/kg, with superior cell-to-pack density, no cobalt/nickel/manganese AFAIK. That is the 350-500 mile range cars and anything shorter.

Sodium Ion will hit 160 wh/kg so that's the 200-300 mile city cars, and no need to even source Lithium. And grid storage.

I haven't done the napkin math, but the high-density LFP should also be the 100 mile range PHEV, which would solve the middle america / rural Africa/Siberia/etc range issues.

That Li-S paper that went through HN about a month ago will probably do those densities, so that would supplant SSB, and would probably (speculating here) drop into existing battery factories more seamlessly.

The drop-in conversions would be a huge boon though, I just don't think SSB will get there soon enough.

SSBs would probably still be able to rule mobile/laptops though, still a big market.

We'll see what happens!

Totally agree. There aren't even completed pilot plants for SSBs. There is nearly 0% chance they will be a majority of the market by 2030. LFP batteries are being made today and even small yearly improvements to energy density will be enough nearly all cars by 2030. Sodium Ion is just coming to market and they look great for grid storage. For transportation CATL is proposing hybrid lithium ion and sodium ion packs to solve some energy density and voltage problems with sodium ion alone.

The cathode is basically just a high nickel cathode like most car batteries. 80% nickel, 10% cobalt, 10% manganese or something along those lines.

The anode is pure lithium metal. The only think you save is graphite.

However of course it is higher density, so less material for the same range.

> Or can these things in theory be made super cheap once the manufacturing scales up?

There are some advantages, like they believe they can remove the formation step in manufacturing.

But the production lines are not very mature at all and making them at modern giga-factory scale will face many problems.

The potential price advantage is from the density increase, not materials or manufacturing itself.

---------------

PS: They also have an LFP product, but its the same concept, same cathode, lithium metal anode.

The increased density seems like it might create cooling, and hence lifetime issues, is lifetime on solid state batteries well known yet? Also, as a resident of an area that gets very hot, does anyone do a good job at self cooling besides tesla packs? Last I heard the leaf lost capacity very quickly in places like Phoenix.

Essentially every other EV maker uses temperature regulation on batteries. Ex: BMW i3 uses A/C evaporator coils in the battery. Chevy Bolts run a coolant plate in the battery that is heated/cooled as appropriate. Nissan Ariyas have a coolant loop in the battery. Ford Mustang Mach-Es run a coolant plate in the battery (actually nigh identical to the Bolt). VW ID.4s use a coolant plate.

Battery don't just innovate on density. They also innovate on how much heat they produce and how they are cooled.

> is lifetime on solid state batteries well known yet?

We need to get away from the term 'solid state' battery. There is not one 'solid state' battery. Just as with Li-Ion there is a massive difference between different versions.

But for non of those batteries we have real live use in large uses-cases like cars.

QS in particular promises pretty good lifetime but they also don't report all the data many people would want to see.

An LFP version sounds awesome, especially if it has pretty good energy density.

> And the car might end up lighter than stock.

This sounds like a good idea but changing the cars base weight can affect its security rating (more likely to flip over).

Additional weights would have to be added in the places that it correspond to parts being removed.

Maybe... depends where weight is added and removed, and how much. Most cars aren't particularly prone to flip in the first place, and a few hundred pounds probably won't make a huge difference. (ICE cars vary in weight depending on whether the gas tank is full or empty, and it's generally not an issue.)

I've heard that having more than 50% of the weight on the rear wheels is dangerous because if you lose traction on a corner it's the rear wheels that would lose their grip first, which is hard to recover from, whereas if the front wheels slip first it's more self-correcting.

a.k.a it'll handle like garbage. You can also just put the appropriate springs in for the after-swap weight instead of adding a bunch of dead mass that will reduce range

My understanding is that QuantumScape are far from the only company working on solid-state lithium-ion batteries, and that they are widely expected to be ready for production at some point around 2023-2028. I don't think they're using especially exotic materials. The challenges seem to be in getting the manufacturing process right.

What will just replacing the gas tank with batteries accomplish? The engine still needs gas.

Unless your comment was sarcastic, I think you read in a diagonal. Read the previous comment thoroughly please:

> EV conversion on an existing ICE car

EV conversion, meaning the motor would be electric as well...

I wasn't being sarcastic, but I don't think the author is stupid and I don't need to beat it into the ground. The phrasing and logic was just weird to me, I don't think it's viable at all if you need to replace the entire insides of the car + paying somebody to do it. It will surely be in the same ballpark to just buy a new electric car.

Batteries are often the hardest part of a conversion, because you need to find a place to put them. The motor can be relatively straightforward, especially if you can just pull out the engine and replace it with a motor using the appropriate adapter and keep the rest of the drivetrain as-is. (CanEV makes bell-housing motor adapters and driveshaft-to-flywheel couplers for a wide range of vehicles.)

A lot of stuff you can just tear out, and that's pretty easy. Exhaust, gas tank, probably the radiator, and so on.

EV conversions don't make financial sense right now because it's usually about $20,000 worth of parts plus a lot of labor to design and build a one-of-a-kind thing. That could change, though. All it would take is some big manufacturer to produce a low-cost kit to convert a common vehicle to an EV, with proper integration into all the existing systems so you can just plug stuff in and have it work. If you don't have to do any structural modifications to the original car and it's just a matter of swapping parts, I could imagine something where a typical mechanic could do an EV conversion in a week or less. And that would be a huge shift. Maybe EV conversion could start to be an economically-sensible thing to do. Most people who want a new car would just buy a new car, but it would be good to have more options available.

Easy is relative. I recently bought a used bicycle whose owner switched to electric. He said he initially looked into a conversion, but the quote he got was in the 1500-2000 range which was pretty much the same cost of the same model just electric. So it was a no-brainer to get a new one. Now, you can get solid conversion kits for under a 1000, and it's a bike so it's much simpler than a car, and therefore actually kind of easy, but what the bike shop wanted was to make money for their time and they of course take the responsibility that it actually works correctly and all of this costs money. And you can do it yourself if you can, but most people wouldn't bother for a bike, let alone a car.

There's a whole bunch of reasons why I think this is not very realistic. But of course people can try and succeed if they want and are able to, no harm there.

I think if the parts were cheap and no special engineering was required, there would be a lot more people doing conversions. (And a lot of local shops that would do it for you if you paid them.) New EVs might outnumber converted EVs 100:1, but even that would be huge. Right now hardly anyone does it because it's super hard and pretty expensive. It just doesn't make financial sense.

(I'm currently in the process of converting a Mazda RX-8, using a Netgain Hyper9 in place of the original engine with the transmission kept as-is, and about 400 pounds or so of lithium iron phosphate batteries.)

You can buy a EV crate motor for about $4500: https://www.fordracingbyspeedshopdirect.com/ELUMINATOR_MACH_...

You do need a battery and the rest of the electronics too. But it's only a matter of time when you start seeing 100% drop-in replacements for classic cars.

Is there even a motor controller (i.e. inverter) available for that motor?

People don't modify their cars to save money.

Right - if you put an LS motor into your car or an electric drivetrain, it's either for the challenge, for more performance or just for the fun of it.

It's enough of a possibility that there are start-ups working on the concept

https://www.youtube.com/watch?v=98mlJ1N50DU

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