Two things missed by the electrek piece:<p>- The article is CC-BY and downloable without scribd horrible UI:
<a href="http://jes.ecsdl.org/content/166/13/A3031" rel="nofollow">http://jes.ecsdl.org/content/166/13/A3031</a>
PDF direct <a href="http://jes.ecsdl.org/content/166/13/A3031.full.pdf" rel="nofollow">http://jes.ecsdl.org/content/166/13/A3031.full.pdf</a>
HTML direct <a href="http://jes.ecsdl.org/content/166/13/A3031.full.html" rel="nofollow">http://jes.ecsdl.org/content/166/13/A3031.full.html</a><p>- In the conclusion the authors mention:
Full details of these cells including electrode compositions, electrode loadings, electrolyte compositions, additives used, etc. have been provided in contrast to literature reports using commercial cells. This has been done so that others can re-create these cells and use them as benchmarks for their own R+D efforts be they in the spaces of Li-ion cells or “beyond Li-ion cells”.<p>So it's science as it should be!
Post of the actual paper;<p><a href="https://news.ycombinator.com/item?id=20908726" rel="nofollow">https://news.ycombinator.com/item?id=20908726</a><p>For those commenting that the discharge rate is too slow in the test, or the depth of discharge was fudged... the tests were run with a high discharge rate combined with 100% charge at storage.<p>> Figure 23 shows the projected fractional capacity of these NMC532/graphite cells as a function of time in years in a scenario where the cells are cycled once per day (100% DOD to 4.3 V) in a cycling event that takes 6 hours. It is also assumed that during the remaining time, cells are stored at full state of charge. It is clear from Figure 23 that these cells would provide an exceptionally long total driving range in an EV if the cells were maintained at an average tem- perature of 20°C. Even if the cells were continually at 40°C, 10 years of lifetime to 70% capacity and a total driven distance of 1,200,000 km is projected. It is worth noting that only 3650 cycles would be required for this total driven distance and 3700 cycles have been demonstrated in Figure 16.<p>> Most important to realize is that Figure 23 assumes 100% DOD cycling on every cycle and storage at full state of charge. If the reader reviews the literature data in Figures 1 and 2, the reader will realize that the lifetime will be much better in situations where the DOD is limited and in situations where cells are stored at lower states of charge. Admittedly, the projections in Figure 23 use the incredibly simple model described by equation 1. It is our opinion that more sophisticated models will lead to even longer lifetime projections.
Short thread commentary on the paper by Ric Fulop (co-founder of A123 battery co. and current CEO/founder of Desktop Metal):
<a href="https://twitter.com/ricfulop/status/1170527207657263104" rel="nofollow">https://twitter.com/ricfulop/status/1170527207657263104</a>
This is very exciting. BEVs that were made before 2016 (I think that was when the last breakthrough trickled down to BEVs in the market) typically had a battery lifetime of about 70k miles or maybe a bit more before reaching 70% capacity. Fast-charging regularly might reduce capacity by several percent points within a few hot summer months. Basically, you bought a car for €30k and it might become useless 5-7 years later. Within a couple of years, we have gone from "I don't know, it's a bit risky to buy" to "My grandkids might be able to use this battery in their static storage system in a few decades".
Can anyone tell whether this is a solid state electrolyte? I’m still hooked on what I saw in that Netflix documentary where the guy was able to cut and puncture the battery without combustion. Also seemed capable of being much more dense.
Having a cell that tolerates 100% discharge seems like a big deal, if it has similar energy density to other modern cells. A lot of lithium-ion cells shouldn't be discharge to less than 20% capacity or so, as it damages the cell.
>> The new battery tested is a Li-Ion battery cell with a next-generation “single crystal” NMC cathode and a new advanced electrolyte.<p>If this is anything like growing single-crystal parts for aircraft, it won't be cheap. The real question should be whether these new battery modules will last twice as long while remaining less than twice as expensive.<p>>> Controlling the charge to less than 100% state-of-charge also helps push the longevity.<p>Um, that is cheating. Running any battery at less than capacity will extend its life. You could put two batteries in the car, run them at 50% or alternate between them, and get double the life. No prizes for that.
"Miles per battery" is possibly the stupidest metric to use to describe a battery capacity.<p>Any battery can last one million miles if it's just sitting on a seat in a vehicle.