Tesla revealed the average battery capacity (and range) degradation for its electric cars in its new Impact Report 2022.
According to the company, the average battery capacity loses after 200,000 miles (322,000 km) is 12 percent of the original capacity. The statement is very general, but there is a chart with Model S/Model X, which suggests that we are talking solely about this platform.
"Even after 200,000 miles of usage, our batteries lose just 12% of their capacity on average."
This is a very interesting data point, especially in comparison with what Tesla was saying previously. In 2021 (Impact Report 2020), the company said that the battery capacity retention, on average, is at about 90 percent after 200,000 miles of usage.
The new data (12 percent loss and 88 percent retention) is a slightly worse result, but let's remember that this is a very dynamic data sample and some things are just rounded. Conditions might be different (temperatures, fast charging utilization, the number of vehicles sold in markets where conditions are more challenging, etc.).
Anyway, assuming a 12 percent loss we can calculate a few things to get a general idea:
- mileage: 200,000 miles (322,000 km)
- capacity retention: 88 percent
- capacity loss: 12 percent
1 percent per 16,667 miles (26,816 km)
1 percent per 67 theoretical full charging cycles (assuming 250 miles per charging), or a higher number of partial cycles
Tesla explains that it does not expect too many battery replacements, because the cars often get scrapped in the United States after roughly 200,000 miles (in Europe it's 150,000 miles).
An electric car, which lost some battery capacity, still can be used by someone for whom the decreased range (from 300 miles to 264 miles for example) is still good enough.
Tesla noted also that when it comes to battery degradation, an important factor is age, especially for vehicles that are not used too often.
"Mileage is only one factor in battery capacity retention; battery age is also a major factor. Retention figures at lower mileages above likely reflect the impact of age while higher mileage values, which come from high-utilization vehicles, likely reflect less influence from battery age."
Those two cars are equipped with cylindrical battery cells (1865 format, NCA lithium-ion chemistry), supplied by Panasonic from Japan. The refreshed version of the car has a new battery pack architecture, but the same cell format. Chemistry evolves over time, so the results for the latest units might be different than the ones from 2012-2013.
In the future, Tesla intends to present more data related to battery capacity retention. There are new EVs (Model 3/Model Y), and new battery types (cell formats as well as chemistry types), which might have noticeably different results.
"Performance of newer chemistries (not yet shown here) can vary and we plan to expand disclosure once we have sufficient data."
We guess, that the LFP lithium-ion battery chemistry would be the top contender in terms of longevity, compared to the high energy-dense NCA and NCM families.
The 4680-type cylindrical battery cells (currently NCM chemistry, as far as we know) would be interesting too.