[sylario]

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.

[fransje26]

> 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-...

[speed_spread]

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.

[alentred]

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.

[scythe]

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.

[toomuchtodo]

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

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

[unwind]

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.

[ChumpGPT]

Banned for using a VPN.

[metadat]

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

[hbossy]

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

[frafra]

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

[TomK32]

I didn't even get to a captcha

[tacker2000]

Same here

[IgorPartola]

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.

[masklinn]

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.

[rich_sasha]

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.

[sylario]

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.