[Matterless]

/Up to 1000 charge cycles/ is a big damper on the excitement, for me. Does anyone know if a limitation like that is inherent to the chemistry here or is this something that they could potentially (hopefully, vastly) surpass?

[bryanlarsen]

That's a comparable rating to the NMC Lithium cells used in an electric car, yet an EV can typically get > 200,000 miles from their cells. A charge cycle is defined as 0% -> 100% -> 0%. If you never do that, you get a lot more effective charge cycles.

Edit:

That's not the full explanation. 300 miles of range for a typical EV * 1000 cycle rating gives 300,000 mile rating.

You likely charge a lot more than 1000 times over those 300,000 miles, but a partial charge counts as a partial cycle.

[beAbU]

To add on to that, battery "lifetime" is typically defined as 80% of original capacity. So after 1000 full cycles, you still have 80% capacity left!

[audunw]

It should be said that at that point you don’t have very many charge cycles left after the capacity drops below 80%, and the capacity will drop a lot faster for every charge cycle after that point.

I don’t have exact numbers.. based on graphs I’ve seen I would guess that if the original cycle life was 1000 cycles you may have another 500 cycles until the battery is actually unusable. But it probably depends a lot on the specific chemistry and how the car is used.

[bryanlarsen]

If 1000 cycles is 250,000 miles, then an additional 500 cycles also seems like a large number.

[magicalhippo]

A study[1] was recently posted[2] which found that for lithium-ion batteries, dynamic use lead to much better battery life compared to fixed-current discharges which is typically used in labs to determine battery life.

From the paper: Specifically, for the same average current and voltage window, varying the dynamic discharge profile led to an increase of up to 38% in equivalent full cycles at end of life.

This tracks well with actual real-world data on BEV battery performance in cars with decent battery management.

[1]: https://www.nature.com/articles/s41560-024-01675-8

[2]: https://news.ycombinator.com/item?id=42370438

[cyberax]

If an EV goes 400 miles on a single charge, then you're looking at 400000 miles of total range! That's absolutely acceptable.

[DennisP]

And at more than double the energy density of today's EV batteries, its range could be considerably longer.

[numpad0]

Up to 500 cycles is the textbook figure for Li-ion cells. Actual performances vary, that's not an indicator of a major problem in the technology.