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Comment by sylario | Hacker News Reader

This summer a French company started to sell sodium ion battery power tool in a major hardware store.

National French research agency announcement: https://www.cnrs.fr/fr/cnrsinfo/batteries-sodium-ion-une-pre...

The power tool : https://www.leroymerlin.fr/produits/outillage/outillage-elec...

Unfortunately, all I could found about the Wh/kg efficiency was an article about the same company saying they were currently able to build cells at 90Wh/Kg in 2017.

Nevertheless, it's not a promise, it's a product currently on sale.

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> company saying they were currently able to build cells at 90Wh/Kg in 2017.

I found an article from 2021 where they were claiming 90Wh/kg to 120Wh/kg, and that they would not go beyond that. They argue that their strength is fast charging, not high energy density, with charges to full capacity in less than 10 minutes.

https://www.ecinews.fr/fr/tiamat-energy-lance-la-production-...

In a vehicle, "fast charging" is not just convenience, it means you can use a smaller, _lighter_ battery having less autonomy but knowing that you can refill it in a few minutes stop. It doesn't make range anxiety go away completely but it makes long trips practical.

Not necessarily. You must have those fast chargers conveniently placed on your route. I can't even imagine going to Vegas from LA with an electric car currently.

LA to Vegas is about 270 miles, which is under the 333 mile estimated range of a Tesla Model 3.

I'm sure under normal conditions, 270 miles would be cutting it pretty close, if it even makes it there at all. Luckily there are 10 supercharges along the way.

Not sure how it is for non-teslas, but I'm guessing at least a few of those places with superchargers also have chargers that will work with other kinds of cars.

There are not so many and the chances of them working are a coin flip.

Driving through the desert on an open road is not conducive to efficiency. It’s hot, need AC blasting. It’s an open road—drive fast! (Or it’s bumper to bumper for 10 hours).

Think about what that means as to a practical limit, today. How many cars per day can make that trip assuming they have to recharge once along the way? It’s far from a solved problem even on that route.

I love electric cars. I’ve been drawing pictures of them thinking about them and waiting for them for a long time. And, I am very grateful for those that made them a reality. That said, I’m also pragmatic. Where we are today versus where we need to be to make them practical for a large portion of the population is sublime.

Each Tesla charging station has anywhere between 10 and 30 ports, so you can charge around 200 cars at the same time, let's say each takes 30 minutes(rather on the high side, 15-20 is more likely) and we have 10 active drive hours.

That makes around 4k can be charged on route, more realistic it's above 10k already.. and that's only Tesla.

Growing pains happen, but I drove my M3 across EU multiple times.. and needed to wait for a charger once, for 3 minutes.

People generally travel at daylight hours, so it’s actually about a third of that. And, worse, people generally travel at peak hours. Again, reality.

There are 3 1/3 daylight hours?

Where exactly is this peak on a 3-4 hour drive where everyone starts with different percentages/takes break at different point in time and software optimizes to avoid overloaded stations automatically?

If it’s impossible to charge the battery in less than 30 minutes, that changes the dynamics of charging a lot.

Exactly. But if two ten minute stops in Barstow and Baker was all it took to make it possible with a cheaper electric car, a lot more people would consider it. Anyway you'll need to stop for a piss.

As another commenter pointed out, LA to LV is actually doable with a number of current on sale EVs, with a decent size range buffer left behind after the trip. Furthermore, there are several fast chargers on the route in Hesperia, Barstow and Baker.

You must have gas stations conveniently placed on your route. I can't even imagine going to Vegas from LA without a horse and buggy currently

The last part felt a little mean-spirited in retrospect. But my intention was to point out that you're just describing a lack of infrastructure yet

Once we build this stuff it's *there for use* and just has the usual burdens of maintenance. Arguably less since we don't need to transport big trucks full of oil to it regularly

Sure, but complaining that someone is noticing the real infrastructure issues doesn’t mean they don’t exist right now?

Not everyone wants to bleed so they can be on the bleeding edge.

There is no lack of charging infrastructure between LA and LV.

https://supercharge.info/map

If you were talking about LA to La Paz then there is a real concern about making it, but LA to LV is no problem at all.

I did a whole trip from SF, national parks, Las Vegas, Phoenix, San Diego, LA, and back to SF in an electric car (Tesla Model Y). This was ~3 weeks ago.

No issues whatsoever.

https://ibb.co/b6N7bdp

The big advantage of fast charging is that charging stations are smaller. With hours-long charging, everyone needs a parking place with a charger. With 20-30 minute charging, you need a big lot with parking stalls and something for people to do for 20-30 minutes. With 10 minute charging, you're almost at gas station throughput. With 5 minute charging, you're at gas station throughput levels.

As I wrote a few days ago, once charging is below 10 minutes, charging stations work just like gas stations in terms of throughput. We will see gas stations converting directly from gas pumps to chargers. (Unclear if gas pumps can coexist near high-powered chargers; gasoline vapor and high voltage electricity should not be in the same space.)

For gas-station throughput, you need replaceable batteries which you trade at the station, or 3-minute charging. With 10 minutes you still need that parking lot and something better than your typical mini convenience store. But - it does go a long way, for sure: 10 minutes is something you're willing to just accept as a stop along your way, while 30 minutes is something that you would try to plan in advance.

From a logistic point of view, replaceable batteries is a nightmare to manage.

It's been tried. See Better Place.[1] Battery swapping was a bet against better batteries. Even in Israel and Hawaii, where you can't drive very far, it was a losing idea.

[1] https://en.wikipedia.org/wiki/Better_Place_%28company%29

Nio, in China, has revisited this, successfully.[1] They have about 2000 battery swap stations and claim to have done 30,000,000 battery swaps so far. They have a few demo stations in Europe.

The idea is to use smaller batteries for cheaper and lighter cars. Range is less but batteries are swappable for long trips.

[1] https://electrek.co/2023/11/21/nio-is-joining-forces-with-a-...

I live in Israel(/Palestine), and I can tell you that Better Place' failure here had very little, if anything, to do with the use battery replacement logistics.

(Of course, electric cars are not a key need in Israel anyways, the country is in dire needs of mass transit system improvement and integration - which would significantly reduce car overuse and congestion problems.)

Can't be much harder than Calor gas cylinders.

The whole battery replacement situation is why EVs depreciate so much.

If swapping batteries in a modular system became a thing, the depreciation problem might shrink...it would also make EVs a lot more appealing to a significant number of people.

I don't see Calor gas cylinder as the same problem as batteries, because you don't drive around with your Calor gas cylinders. You bring it home, and you bring it back.

With battery, the main issue I see is the same as cities encounter with shared-vehicle: sometimes many people go at the same time from place A to place B, which lead to empty stations and overflowed stations. And you end up having to compensate this effect A LOT.

I admit that the problem is not intrinsic to battery-swap, it's more that it's not adapted to the way people move around. And as people don't move around randomly (which might be the best scenario), the solution is not as simple as the Calor Gas cylinder problem.

Replaceable battery isn't easy and likely won't happen for cars. Maybe for airplanes when the time comes, but even then I'm a bit skeptical... Maybe for part of it for bigger jets.

3min is better than 10min, but ask anyone if they'd prefer to fuel up 3 times slower and pay half the cost and I bet most everyone would say they would.

For fueling up, you must be there until it's done. For charging you don't. You connect your car and go inside the convenience store. With 10min, that's excellent. Chances are most everyone will either exit their vehicles, plug it in, go back inside their vehicle for 10min, walk around for a bit, or go to the store for a quick errant. In any of those cases the experience will be better than dealing with fuel.

China is already doing it. Replaceable batteries are seen as the way to go over there and multiple companies are already offering it. Drive your car in and a robot will drop the old battery out and lift a new one in. No more hassle than a carwash.

It definitely works well for scooters where you don't need much real estate to put in a swap station.

https://www.gogoro.com/gogoro-network/

The swapping station looks fine for a new technology endlessly claimed not to work. (lmao)

https://youtu.be/qd0WPw3p2MQ

Lets not stop there, you also want to be able to dispose of the battery if you can no longer control the heat.

Currently the solution is to submerge the entire car or let it burn out on the spot. Takes about 2 days but it can randomly reignite.

https://youtu.be/lF-ubRP2ihc

Just off highway 80, the first exit after crossing the Yolo bypass on the way from Davis into Sacramento, there's a 7-eleven store/gas station/ChargePoint.

The chargers are not right in with the pumps, but not all that far either.

Street view link but the imagery is 6 years old so no ChargePoint visible. The chargers are where the unhitched semi cab is parked. You can see better pictures by looking at user submitted photos for the ChargePoint. https://maps.app.goo.gl/EEnpFRwwv49fkUPo7

Hate to be that pragmatic engineer...but wouldn't a decent balance between range and fast charging be nicer? I'd like to see the graph for capacity vs charging time for these cells.

I'm sure like any battery the charging gets slower over time as the battery warms up, so finding the sweet spot would be nice.

I'd quite like to buy an electric car and select an appropriate power bank based on this.

Also, why do the packs have to be permanent? Why not have the ability to add or remove modular cells as and when needed? Just add the capacity when you need it. Plug the unused cells into your solar array when you aren't using them.

That opens up a few options. Firstly, you can choose to power your house or your car, or of you need to get to work and you forgot to charge, you take the dead cells out and swap a fully charged set in. Leave the dead ones charging at home.

Have a modular system where battery swapping is possible doesnt seem to be a system that EV manufacturers have considered for some reason.

It's a perfectly good tradeoff, absolutely. Even more so because the sodium-ion batteries run cool, contrary to the the Li-ions, meaning that their installed energy-density is a lot closer to their theoretical energy density, which is not the case for Li-ions.

Interesting. The second web site cites a number of advantages of the sodium-ion battery:

> Sodium is 10 times faster to charge than lithium, and safer because of its low operating temperature. The number of recharging cycles is up to 5 times greater than lithium. Another advantage is that sodium is more widely available and accessible on the planet, and its processing has less impact on the environment.

Worth noting that Tiamat's battery is sodium vanadium fluoride phosphate, not sodium ferrocyanide. So, these are not quite the same technology. Vanadium costs a similar amount as nickel and has a higher abundance, but the present-day annual production is much lower. The long-term resource outlook for vanadium is unclear.

Sodium ferrocyanide ("Prussian white") was claimed by CATL as well, though they have been supplementing it with lithium in cars for some reason. The cynic in me thinks that the lithium is there to stabilize unfavorable cycling characteristics of the sodium; the optimist hopes it is just because lithium is cheaper at scale right now.

https://web.archive.org/web/20231121142135/https://www.cnrs....

https://web.archive.org/web/20231121142300/https://www.leroy...

I was banned from the second site (like many other commenters), and got a chuckle from how switching the first from FR to EN did not, in fact, translate the actual content.

Silly me for expecting that, I guess.

Banned for using a VPN.

I got banned and am not even using a VPN! Overly aggressive bot protection.

It's the first time a captcha tool flagged me as robot and banned from their site.

Same here

00100011 01101101 01100101 01110100 01101111 01101111

They're French. They don't care about your suffering <puffs on cigarette>

I didn't even get to a captcha

> There is a robot on the same network [...] as you.

They are banning entire countries (violating the EU geo-blocking directive as well, probably).

The entire product weighs 0.5 kg, and it is 0.7A at 3.6V. I assume the amp rating is really amp-hours, which would give it 2.52Wh. Figure the battery is half the weight of the tool, which would give it roughly 10Wh/kg.

The spec sheet on the store is confusing. It says :

Intensity(Ah) Less than 1.5

Tension (V) 3.6

Amperage (Ah) 0.7

Edit : the box indicate 0.33 Kg, the 0.5 weight probably include the charger and other parts.

According to https://www.sciencedirect.com/science/article/abs/pii/S03787... the batteries Tiamat produces are 18650 format, 3.7V, 0.61Ah. The latter more or less matches the specs of the product. This would mean the product might have a single 34g battery with a specific energy of 68Wh/kg, and 135Wh/L. So low end of nimh. Which sounds somewhat reasonable, 10 (and around 20Wh/L) I don’t think you’d bother even going forwards with.

Sadly I can’t find any teardown of the product, it’s all just press reprints.

There’s a split view PDF (in the documents section), it doesn’t seem to show the battery but does not show a huge amount of space for it.

I got the same 68 Wh/kg from this report: https://www.greencarcongress.com/2023/10/20231030-tiamat.htm...

Low end of Nimh doesn't sound very great, but - what if you could get 18650 cells for (making up a small number) $0.50 each? I think I would end up with a box full and just swap them as I use them. Even better if they retain charge well.

It has other great advantages over NiMH: fast charging, no memory effect, no self-discharge

Absolutely! However my baseline are my Li-ion 18650 cells which have those advantages as well, in addition to larger capacity. But I think I would be willing to give up the capacity if the price was much lower.

Yeah, considering the tradeoffs it has to be much cheaper to be worthwhile. I would say 5-7 euros per cell retail to be worth considering. Otherwise why bother ?

NiMH doesn't have noticable memory effect. NiCd does.

NiMH self-discharge is low enough to not matter for most applications. 5th generation Panasonic Eneloop is 90% after 1 year of storage, 80% after 3 years, 75% after 5 years, and 70% after 10 years.

This paper describes Tiamat's battery as Na3V2(PO4)2F3:

https://chemistry-europe.onlinelibrary.wiley.com/doi/pdf/10....

How much of that weight is the essential weight of the battery, and how much is consumer-friendly outer shell, electronics, other one-offs etc.? I.e. if you wanted to take the same tech, put it in a non-consumer-facing context (say a grid-scale battery) and wanted to make it 100x the capacity, would it be 100x the weight?

I can imagine a lot of the weight of the battery unit itself isn't necessarily the battery, if that makes sense.

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