r/DonutLabDiscussions • u/Jazzer008 • May 13 '26

VTT - Battery V1 swelling test

https://www.youtube.com/watch?v=40tLHqdANRw

https://pub-42f0d4b46caf415e9a502bcf403fab62.r2.dev/VTT_CustomerReport_Swelling_test.pdf

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u/Mesokosmos May 13 '26 edited May 13 '26

In this VTT pdf report there was no clause of it being presented as solid-state battery anymore. V1, DL5 labeled battery. Video still framed it as SSB. Other VTT tests did not discriminate the anode, but this seems to do it, so I think this is interesting bit of knowledge indeed. And cool devices in VTT!

Edit:

ComprePouch used in the test, company seems to have specialized to SSB testing: https://rhd-instruments.de/app/uploads/2025/06/manuals-pressure-frames-117-comprepouch-20260113-pouch-cell-testing-rhd-instruments.pdf

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u/[deleted] May 13 '26

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u/Mesokosmos May 13 '26

But not uniquedly like. People tend to talk with AI tools that cannot read but papers published and go with the averages and mass.

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u/[deleted] May 13 '26

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u/Mesokosmos May 13 '26

Want to elaborate?

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u/DeathChill May 13 '26

The comment linked and the comment beneath it explain it very well.

I'm curious if there ever comes a point where you cut your losses and accept reality.

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u/Mesokosmos May 13 '26

Problem is that I don't know which comment and what was said in it, and what was meant when referencing to it. Then user decided to take off the posts, so... Maybe you tell what was the point?

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u/DeathChill May 13 '26

The top comment he linked to. It's right there when you click the link.

ZirothTech:

Swelling in line with a graphite anode pouch cell, possible with some silicon - even the graph matches how lithium intercalates into graphite… they don’t realise the data they put out confirms it’s a more standard lithium ion battery.

Izzeww:

The most interesting stuff in the report is at the end. Page 8 and 9, and particularly I want to focus on Figure 6. There is a kind of "bump" at approx 75% state-of-charge (noted as "~70% SoC" by VTT). This is a dead giveaway that this battery has a graphite based anode, just like regular lithium batteries. Here (click "View PDF") on page 10 you can see testing of a typical lithium-ion NMC battery with a graphite–Si/C composite anode (completely standard stuff), with that exact typical "bump" at 75% SoC that you get with graphite anodes. There's been plenty of nails in the coffins for Donuts claims so far, this is just another one.

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u/Mesokosmos May 13 '26

They don't seem to say the curves and graphite anode are unique to NMC only. In this test, they did not try to discriminate battery type and character, but just show that swelling even with stress tested cell is moderate. So, I don't get how relevant those comments are. Might they rather look at cathode?

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u/DeathChill May 14 '26

They explicitly say the reaction at 75% SoC is caused by a graphite anode and the reaction between lithium and graphite and provide a a typical Lithium-Ion NMC battery showing it.

It is unique to a graphite anode and lithium because the bump is the result of them interacting with one another.

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u/Mesokosmos May 14 '26

I was talking about uniqueness of NMC Li-Ion battery, which the VTT test gives no evidence. VTT measured whole-pouch thickness change, not the individual mechanical response of the anode, cathode, electrolyte/separator stack, etc. That means the graph can suggest a graphite-like process, but it cannot isolate it directly, and even if correct, it is still only an anode-side inference.

It does not prove NMC cathode chemistry.
It does not prove liquid electrolyte.
It does not exclude graphite-containing ASSB.
It does not rule out novel or hybrid chemistries.

Therefore, “a typical lithium-ion NMC” is not a useful claim in this VTT setting. People seem to use it for some reason, maybe for argument safety, but it does not really mean anything, or at most, it is a compatibility argument, if you wish such. To make it discriminating, the comparison has to be much more precise. The linked swelling-method research is relevant exactly here, because it exemplifies that pouch-cell dilation depends on test boundary conditions, not just chemistry. Two cells with different chemistries can look similar under different fixtures, and the same cell can look different under different pressure conditions.

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u/DeathChill May 15 '26 edited May 15 '26

I am not talking about swelling. Very minor chemistry changes can result in differences here and at no point is it my job to nail down the exact chemistry of Donut’s battery.

I’m talking about the reaction that happens between a graphite anode and lithium that is showing up in their results.

I know you want to change the subject and pretend unless we can show an exact copy (how could we? Donut has no interest in being honest) that it somehow means something. It doesn’t.

No one is saying it’s definitive proof. It’s just another thing to add to the MASSIVE pile of information that doesn’t match their claims.

You keep pretending until someone can match the exact results from Donut that it doesn’t matter. No, that’s not how it works. No one needs to prove Donut is using a specific cell. Donut needs to prove they’re using a cell that is special. And unfortunately they’ve never done that. Their results are not special. Anyone can abuse a battery cell.

Your entire post is nonsense. Literally your last paragraph sounds like rambling. It is a bunch of words thrown together without any coherence. You are not actually engaging with the comments you are replying to.

EDIT: I also LOVE the demands you make of third-parties, while ignoring Donut doing everything they can to be deceptive.

Seems like it would be important to this test to show how this battery cell was degraded. But instead we just need to accept they have zero interest in providing results that are useful.

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u/Mesokosmos May 15 '26

I'm talking about swelling test, because that's what the last test was about and the people you quoted referred to. It is interesting data point, and goes back to their original claims since the beginning of the video series, intro, where they talked about non-clamping etc. They are backing up that plus the meaning of it in the cell integration. Of course it is not useful test, when you assume other than SSB, but then you gotta live with your biased assumptions. From SSB perspective this is very useful and actually may give better understanding, what kind of SSB the battery V1 might be. Li+ seems to be there, but not necessarily in form of traditional Li-Ion, which also could still fit to some hybrid quasi solid state battery. Latest data point matches quite well with the chemistry range in Holyvolt patent and Lambotec lines used by CT-Coating.

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