alt Hacker NewsResearch on the current EVs shows that they degrade by on average 2.3 % of original capacity a year, but there is a strong dependency on how much the vehicle is used and how often it is DC fast charged, i.e. there is time based degradation and usage based degradation.
Low use vehicles have degradation of 1.5 % a year, heavily used vehicles mostly slow charged had degradation of 2.2 % a year and heavily used vehicles mostly fast charged had highest degradation of 3 % a year.
Now before you think that means the capacity will halve in X years (33, 23 and 17), the article also notes that the degradation is not linear and it was faster in new vehicles and then slowed down - with no way to know if it will slow down further or continue in this manner, etc, until we have a sufficient sample of 20 years old modern EVs.
Link to article https://www.geotab.com/blog/ev-battery-health/
Replies
Where does "20 years" come from? What's wrong with "10 years"?
At the 200,000 mile mark battery life is expected to be ~85%. That's what actual data shows. 200,000 is 13 years of driving 15,000 miles a year.
https://recharged.com/articles/tesla-model-y-battery-degrada...
> the article also notes that the degradation is not linear
Battery degradation is affected by multiple processes which respond primarily to different factors, such as heat, cycles or just time.
This[1] paper goes into some detail about that, and also notes that the typical way batteries were evaluated for longevity in the lab significantly overestimates the degradation compared to batteries used with real-world dynamic loads.
Some quotes:
We found that dynamic cycling enhances battery lifetime by up to 38%. Moreover, we determined the window for the tip-over C-rate that balances time-induced ageing and cycling ageing for this commercially relevant chemistry to be approximately between 0.3C and 0.5C, in the range of realistic average C-rates.
Figure 4a,b illustrates that the degradation is initially dominated by the loss of lithium inventory (QLi). [...] However, as the batteries age, additional degradation mechanisms become important. On the one hand, the positive electrode capacity loss dominates and is impacted by the rest fraction at high SOC [...]
On the other hand, the negative electrode capacity loss (which is less than the positive electrode capacity loss) is impacted by the DoD [...]
Figure 4d shows that, in particular at low average C-rates, when the DoD is beyond 85%, the negative electrode capacity degrades more rapidly, while cells avoiding deep discharge have more preserved negative electrode capacities, in agreement with Fig. 3e. In addition, the DoD has no impact on the positive electrode capacity (Fig. 4e).
SOC = State Of Charge
DoD = Depth of Discharge
[1]: https://www.nature.com/articles/s41560-024-01675-8