Comment by mrabcx
2 days ago
"lithium-ion batteries .. degrade after just 1,000 cycles" If you charge your car battery twice a week and complete a full cycle then we are still talking about like 9 years to reach 1000 cycles. If you charge your phone every day, and do a full cycle, then we are close to 2.7 years. But you will probably not do a full cycle. So, I guess lithium-ion batteries are not really that bad.
Don't forget calendar life. Lithium batteries degrade over time even if you do not cycle them. The life of the commonly used chemistries is only around 3 years.
Explain my 7.5 year old EV with 95% battery health and 65k miles driven?
Your 2nd sentence has issues with reality.
Some EVs start with capacity “gated off” to limit the depth of early cycles and provide a more graceful degradation.
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It depends on your usage too, along with the exact chemistry and form factor of the lithium battery.
A lot of people report lithium batteries swelling up in their phones/tablets around 3-4 years of usage.
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The explanation is simple. OP said commonly used chemistries. That would be something like LCO. Your EV battery is probably NMC.
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Degrade to what extent? I have a 12 year old Nissan Leaf that's lost maybe 25% of its range. Still absolutely usable as a neighborhood car.
A 2013 Nissan Leaf should get 60-75 miles of range (depending on how much of thebattery you use, as well as climate, and other driving conditions). If it got ~80 miles new, it would still get 60 miles now. That might be enough for someone to make a short commute, though unless they have relatively fast charging at home, a 20+ mile commute 5 days a week might be tough to pull off. But most errands would fall well within the existing / remaining range.
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I think most testing uses 80% capacity as the cutoff point. Largely because that's when the loss in capacity really slows down.
> neighborhood car
Not familiar with that term, what does it mean? Shared ride? A car for walking distances?
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If it has moved like 250K km then it is impressive.
There's also some research[1] suggesting that dynamic cycling extends lithium-ion battery life, compared to the fixed charge/discharge cycles typically done in a lab setting.
In this study, we systematically compared dynamic discharge profiles representative of electric vehicle driving to the well-accepted constant current profiles. Surprisingly, we found that dynamic discharge enhances lifetime substantially compared with constant current discharge.
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.
[1]: https://www.nature.com/articles/s41560-024-01675-8
But it could be very interesting for commercial or industrial use: commercial vehicles that are constantly driven and charged, power reserve batteries, tools...
And I guess that you could make devices with smaller batteries and fast charge, with less fear of wearing them early.
We even lived to see lithium ion batteries redefine what battery powered devices can even do!
I remember my parents first Dell laptop with a whopping 2 hour battery life, if you weren’t doing anything processor intensive, otherwise it was basically a UPS.
For grid-level solar energy, we will need batteries that cycle at least 200 times per year. A system that requires replacing batteries every 5 years can't really be described as "renewable energy".
As long as "replace" includes "take the old batteries and turn them into raw materials for making new batteries" it definitely can.
Typical issues with old batteries are things like dendrite growth. There's nothing wrong with the materials that went into making the battery, they've just reshaped themselves into an unfortunate spiky structure.
Note that LiFePO/LFP batteries used in cars and large installations are rated for 5,000+ cycles. They really are on another level compared to Li-Co phone batteries that top out at 1,000.
Most EV map displayed 0% to 100% to something like physical 5% to 95%, or even more extreme, to help.