Tesla Battery Degradation Analysis

There is a lot of anecdotal information regarding battery degradation rates. Some argue that battery management is essential, while others claim it isn't necessary.

This article examines actual battery degradation rates based on an analysis of around 1,500 Tesla vehicles, primarily Model S, Model Y, and Model 3.

1. Subjects and Types of Battery Packs

Even among the same Tesla models, different battery packs are used depending on the production period. For example, Model 3 and Model Y vehicles use battery packs from various manufacturers such as Panasonic, LG Chem, CATL, and BYD.

2. Battery Degradation Over Time

First, let's look at battery degradation based on time. The degradation rate observed is slightly faster than commonly believed, with considerable variation even within the same battery pack type. Some battery packs exhibit degradation of 10-15% within two years. A degradation of approximately 20% is anticipated around 6 to 7 years. Furthermore, even identical battery packs exhibit degradation variation in the range of 5-10%.

This variation likely arises from manufacturing tolerances as well as differences in driving habits, charging practices, and temperature management.

3. Battery Degradation Relative to Mileage

When considering driving distance (km), certain battery packs show approximately 15% degradation around 50,000 km.

Tesla typically provides an 8-year/160,000 km warranty on batteries. Based on this data, significant issues are unlikely during the warranty period. However, if planning to exceed 200,000 km, battery degradation is likely to become more apparent.

4. LFP vs NCM

Contrary to the widespread belief that LFP (Lithium Iron Phosphate) batteries last longer, the data shows NCA or NCM batteries have lower degradation rates compared to LFP batteries. Of course, various factors including manufacturer, production time, and driving habits play significant roles. Thus, rather than concluding that LFP batteries are poor, it would be more accurate to say that under specific conditions, LFP batteries may degrade faster. A possible explanation is that users may operate LFP batteries under harsh conditions such as rapid acceleration, fast charging, and strong regenerative braking at low temperatures, resulting in higher C-rate usage.

5. Battery Degradation by Model Variations

Battery degradation also varies based on the specific model. Standard Range and Performance models show higher degradation rates compared to Long Range models, indicating a correlation between higher C-rates and increased degradation. Performance models, built for higher sports performance, have higher power output demands, which can accelerate battery degradation. Similarly, Standard Range models, due to their smaller capacity, may also degrade faster under frequent high C-rate charging and discharging conditions.

6. Conclusions and Recommendations

Within Warranty Period (8 years/160,000 km)

Statistics suggest minimal battery issues within Tesla's official warranty period. Therefore, if planning to operate your vehicle within this range, extensive concerns regarding battery degradation are unnecessary.

Long-Distance Travel (200,000 km or more) or Second-hand Purchase

At or beyond 200,000 km or 8 years, degradation could reach between 20% and 30%. Batteries exceeding 30% degradation are officially considered no longer suitable for use. Thus, effective battery management becomes essential for those planning long-distance travel or considering purchasing a used vehicle older than 8 years.