Electrochemist and battery scientist, tweets mostly about lithium batteries. 🇬🇧🇸🇪 Lithium Inventory: https://t.co/IE6EWTxLow
Jul 18, 2022 • 48 tweets • 13 min read
So I had been meaning for a while to do a little commentary on the Tesla 4680 teardown organised by @LimitingThe, partly because teardown is part of my day job... so here come some observations, starting with the "part 1" video: /1
4:27 - Cell voltage is pretty low, 0.14 V - which is way below the usual 0% SoC. The cell is dented, but the voltage is not zero, so tells me it's not short circuited (at least at the time of teardown) - guessing it was discarded from the line and hasn't gone through formation /2
Jun 26, 2022 • 21 tweets • 5 min read
Are Prussian Blue analogue (PBA)-based Na-ion batteries safe? Safer than LFP? It's been argued to me a number of times that no oxygen in the cathode means no thermal runaway, but is that true? I think the evidence suggests no, and the hazards may actually be quite significant: /1
For those not familiar with Na PBAs, they are compounds with general formula NaxM[M'(CN)6] where M and M' are transition metals (e.g. Fe, Ni, Mn). The structures are quite stable but in principle can decompose at high temperatures, releasing the cyanide (CN) ligand. /2
Jan 28, 2021 • 4 tweets • 2 min read
Another creative excuse from a Swedish public official
Head of @Folkhalsomynd says: "I missed that the time was in the commuter hours", after being spotted breaking rule on face masks on public transport during commuter hours, on his regular commute
svt.se/nyheter/lokalt… /1
I'm still impressed by our state epidemiologist's brazen "I'm standing far in front of the others", after being photographed manifestly not keeping distance at a Gothenburg restaurant last year
Seems my threading earlier on @QuantumScapeCo went a bit bananas, so I'll collect some general post-presentation post-dinner thoughts/questions/observations under here... 1/
So finally we got to see some cycling data: 1 hour charge/discharge, practical capacities, >800 cycles achieved seemingly quite readily - for a so-called anode free Li metal cell these results are very impressive! 2/
Settling down for the much-anticipated #QuantumScape reveal. A little taste of this already on their website, link below. Feels like a thread coming on... ir.quantumscape.com/news/news-deta…
Interesting to hear from the start a clear disclaimer about this showcase presenting "forward looking statements", making clear that reality might differ from expectation outside of QS's control
Sep 5, 2020 • 13 tweets • 4 min read
Some additional thoughts and numbers on #QuantumScape. Long story short: my estimate is that an "anode-free" solid state cell should fetch ~350 Wh/kg, in the absence of some new miracle positive electrode. Bit lower than 380-480 Wh/kg QS have stated. Thread... 1/
My starting point for my (medium crude) calculations is Tesla - they have probably the most energy-dense +ve on the market now: NCA w/ 90% Ni and a high capacity of ~4.5 mAh/cm2. My cell model gets pretty close to the Model 3 2170 cell numbers, so it's an ok starting point. 2/
