Tesla battery researcher unveils new cell that could last 1M miles

"Miles per battery" is possibly the stupidest metric to use to describe a battery capacity.

Any battery can last one million miles if it's just sitting on a seat in a vehicle.

Okay there you're becoming too Aspergers and literal about language.

A more positive read would be that this new battery lasts as many charges are necessary for a model 3 equipped with a battery pack of this type to drive 1 million miles. (Which is how I interpreted it.)

>> The new battery tested is a Li-Ion battery cell with a next-generation “single crystal” NMC cathode and a new advanced electrolyte.

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.

>> Controlling the charge to less than 100% state-of-charge also helps push the longevity.

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.

Post of the actual paper;

https://news.ycombinator.com/item?id=20908726

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.

> 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.

> 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.