Tesla 4680 batteries showed worse performance compared to competitors, despite Elon Musk's claims of their superiority

Battery Problems of the Tesla 4680: Five Years of Experience and Unexpected Findings

In September 2020, Elon Musk introduced a new line of battery cells, the 4680, at an investor event. According to him, they were supposed to store five times more energy, increase range by 16 %, and be lighter than the standard 2170 cells used in traction batteries of the same capacity. However, after almost five years of working with these cells, it became clear that most of the claimed advantages did not materialize.

What Musk Said
At last year’s Tesla shareholder meeting, Musk admitted that the decision to use a “dry” electrode manufacturing technology turned out to be more difficult than expected. This led to delays and additional costs in implementing the 4680 cells.

Comparison with Competitors
Metric 4680 (Tesla) Panasonic 2170 Energy Density 244 Wh/kg 269 Wh/kg Difference –13 %
*Low density leads to a heavier traction battery for the same capacity.*

Capacity on Assembly
- Tesla Model Y (8L series): nominal capacity 79 kWh → actual 74 kWh.
- LG 5M: 82–84 kWh.

A difference of 5 kWh can significantly reduce range, especially under the WLTP cycle.

Range
Replacing the rear drive LG with Tesla’s own 4680 cells in the Model Y Premium Long Range reduces the range by 8 % (to 609 km). That’s almost 52 km less, noticeable even with nominal measurements.

Weight and Charging
- The reduction in traction battery weight in the European version of the Model Y is only 18 kg, down to 447 kg.
- During fast charging, 4680 cells overheat faster, causing a drop in charging speed: from 10 % to 80 % takes more than 40 minutes, whereas a comparable model with 2170 cells charges in 30 minutes.
- After reaching 35 % capacity, the charging power drops below 100 kW.

LFP Batteries
Cheaper LFP batteries, although having lower capacity, charge faster than 4680s. From 2025 Tesla plans to use batteries up to 250 kW, but independent tests are not yet available.

Supply and Demand
4680 cell suppliers report a sharp decline in raw material purchases. This is mainly due to the low popularity of the Cybertruck (the main consumer of these cells) and the lack of large-scale production growth. In Europe, the Model Y is equipped only with one trim based on 4680, and buyers often receive cars with lower range without knowing in advance which version they will get.

Conclusion
Five years of working with Tesla’s 4680 batteries have shown that:

1. Energy density is lower than Panasonic 2170.
2. Actual capacity at assembly is less than claimed.
3. Range decreases by 8–10 %.
4. Battery weight reduction is only marginal.
5. Charging is slower due to overheating.

Thus, Tesla’s own cells turned out to be worse than purchased ones in most key parameters, negatively affecting both vehicle performance and the manufacturer’s reputation.