Detailed breakdown on Tesla's new battery design

[OKIsItJustMe]

6. Tesla's 4680 battery cells are underperforming and frustrating buyers

https://electrek.co/2026/05/07/tesla-4680-battery-cell-performance-data-shows-cant-build-own-cells/

Fred Lambert | May 7 2026 - 9:50 am PT

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.

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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.

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Here is what the actual data shows after five years of production:

Energy density: Tesla’s 4680 cells produced at Giga Austin have a nominal energy density of 244 Wh/kg. The Panasonic 2170 cells they are meant to replace sit at 269 Wh/kg. That’s 13% worse, not better. Tesla claimed higher density in the latest version, but they haven’t been tested yet.

Battery capacity: The new 4680-based “8L” pack going into European Model Y vehicles carries approximately 79 kWh gross (74 kWh usable). The LG 5M pack it replaces in the exact same trim — the Model Y Premium Long Range RWD — had 82-84 kWh. That’s roughly 3-5 kWh less energy in the same car.

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(Follow the link for the whole sad story.)

For those who wonder how an EV battery pack is built, I recommend this video from Munro: