Tesla’s 4680 battery cells are underperforming and frustrating buyers

Five years after Tesla (TSLA) unveiled its 4680 battery cell at Battery Day with promises of 5x the energy, 6x the power, and 16% more range, the data tells a very different story. Tesla’s homemade cells consistently deliver worse energy density, worse charging performance, and less range than the supplier cells they are meant to replace.

The problem is getting harder to ignore now that Tesla is quietly swapping supplier batteries for its own 4680 cells in European Model Y vehicles — and owners are noticing the downgrade.

What Tesla promised vs. what Tesla delivered

At Battery Day in September 2020, CEO Elon Musk presented the 4680 cell as a revolutionary leap. The larger format (46mm diameter vs. 21mm for the 2170 cells) combined with a “tabless” electrode design was supposed to hold 5x the energy of existing cells and deliver 6x the power. Tesla said the cells would improve range by 16% at the pack level, cut costs in half, and enable a $25,000 electric car.

The centerpiece technology was the dry battery electrode (DBE) process, acquired from Maxwell Technologies, which Tesla said would dramatically simplify manufacturing. At the 2025 shareholder meeting, Musk himself admitted the dry electrode process was a mistake, saying it turned out to be “way harder” than expected.