What Tesla promised in 2020
On September 22, 2020, at an event Tesla called Battery Day, the company announced a new battery cell it named the 4680, after its size, 46 millimeters wide and 80 millimeters tall. Tesla said the cell used a tabless design, meaning the thin metal foils inside connect straight to the terminals instead of through a narrow tab, which the company said lets current flow better and heat escape faster. From the new shape alone, Tesla said the cell would deliver 5 times the energy and 6 times the power of the cell it was replacing, add 16% more range and cut cost per kilowatt hour by 14%. Combined with new chemistry and new factories, Tesla said the wider plan could cut total battery cost by 50% and enable a 25,000 dollar electric car.
These are Tesla own 2020 claims from the new cell shape alone, at the event Tesla called Battery Day. Tesla stated the energy gain as 5 times, shown here as a 400% increase, a MAOWCE conversion from the multiplier the source states to a percent so it sits on the same axis as the other 2 bars. The 6 times power claim is not charted, it does not sit on the same percent scale as a 14% cut, and runs in the body text instead. A separate, wider promise of a 50% total cost cut and a 25,000 dollar car depended on new chemistry and new factories as well, and is not part of this chart.
Show the numbers
| Energy up 400% | 400 |
| Range up 16% | 16 |
| Cost per kilowatt hour down 14% | 14 |
What ships today
Nearly 6 years later, the cells Tesla actually builds at its factory in Austin, Texas, measure 244 watt hours per kilogram, a measure of how much energy a cell holds for its weight, according to Electrek reporting. The Panasonic cell the 4680 was meant to replace measures 269 watt hours per kilogram, 13% more energy for its weight than Tesla own cell delivers. An independent laboratory benchmark of a newer rival cell found a similar gap against a real, physically measured Tesla 4680 cell, which supports the Electrek figure.
The pack got swapped twice in public
In 2026 the shortfall became visible in a real car. Tesla had already replaced its own 4680 cells in the European Model Y Premium Long Range RWD with a pack from the supplier LG, then swapped its own 4680 cells back in, inside a smaller pack Tesla calls the 8L pack. The 8L pack holds approximately 79 kilowatt hours gross and 74 kilowatt hours usable. The LG pack it replaced, in the exact same trim, held 82 to 84 kilowatt hours. On the same test used to state a car official range in Europe, that change dropped the range from 661 kilometers to 609 kilometers, a fall of 52 kilometers, 8%.
European Model Y Premium Long Range RWD, same trim, same test. The old LG pack held 82 to 84 kilowatt hours. The new Tesla built 8L pack holds approximately 79 kilowatt hours gross, 74 kilowatt hours usable. The drop is 52 kilometers, 8%.
Show the numbers
| Old pack, made by LG | 661 |
| New pack, Tesla own 4680 cells | 609 |
The money and the scale behind the promise
The numbers around the cell tell the same story. A 2.9 billion dollar contract with the South Korean supplier L and F, signed specifically for 4680 cathode material, has been written down to 7,386 dollars, a 99.9% reduction, L and F own disclosure shows. Tesla once set a goal of 100 gigawatt hours of 4680 production by 2023, rising to 3,000 gigawatt hours by 2030. Today the cells run in only that 1 limited Model Y trim in Europe and in the Cybertruck, which sells at roughly 20,000 to 25,000 units a year against a factory built to make 250,000, about 1 in every 10.