Tesla’s New Patent Promises a Significantly Lower Production Cost For the 4680 Battery Cells, Which Power the Cybertruck & Tesla Model Y

For those of us who have followed Tesla for a while, the company’s Battery Day presentation in September 2020 was one of the most exciting events.

At that time, Tesla outlined its plan to revolutionize battery production by applying a first-principles approach.

However, five years on, the promise of the revolutionary 4680 cells remains more of an impressive presentation than an actual reality.

Tesla has faced significant challenges in implementing some of the breakthroughs it previously outlined, with the dry-cathode process being the biggest bottleneck.

Currently, cylindrical batteries are made by coating two long metal sheets with anode and cathode materials, separating them with a layer, and then rolling the sheets together.

This creates a cylindrical shape, and the roll is placed inside a can that forms the battery's outer shell.

In this process, the cathode and anode are mixed with a solvent to create a slurry, making it easier to coat the materials onto the metal sheets.

However, these solvents are usually toxic chemicals and serve no purpose in the finished battery other than helping the anode and cathode adhere to the metal sheets.

To eliminate these harmful solvents, battery manufacturers must construct large ovens to dry the wet slurry, along with waste treatment and other expensive, time-consuming procedures.

By using the dry cathode method, Tesla aimed to eliminate this step and bond the dry cathode material directly to the aluminum sheets.

But during large-scale manufacturing, the cathode, simply rolled onto the aluminum while still dry, kept cracking, which hindered production throughput.

This issue remains the primary barrier to achieving much lower-cost 4680 batteries. Tesla has been addressing this for years, and a recent patent suggests it might have found a solution.

Joe on the Cybertruck Owners Club forum neatly summarized how the new patent addresses the challenges of dry-cathode manufacturing.

He writes…

“A new patent, US 2025/0364562, published on Nov. 27, 2025, reveals a scientific breakthrough that enables Tesla to finally switch its 4680 cells from a "hybrid" manufacturing model to the fully dry-electrode process, which has traditionally been impossible to mass-produce.

This patent comes at a crucial point for the 4680 program.

While Tesla has successfully mass-produced 4680 cells for the Cybertruck, these "Gen 1" cells are effectively hybrids: they use a dry-coated anode (implemented early) but still rely on a traditional wet-slurry cathode.

The wet cathode process was very difficult to replace because the powder was too brittle and abrasive, forcing Tesla to keep large, expensive drying ovens and solvent recovery systems in use for half of the battery.

This patent outlines the "Gen 2" dry-cathode fabrication process that finally eliminates these steps.

The main innovation is the development of a specific polytetrafluoroethylene (PTFE) composite binder material.

While PTFE is valued for its fibrillation properties—its ability to stretch into microscopic "hairs" that physically bond powders into self-supporting films—it has historically suffered from electrochemical instability at low voltages.

This instability causes excessive lithium consumption and Irreversible Capacity Loss (ICL), which is the amount of energy capacity permanently lost during the battery's first charge cycle.

Tesla’s solution addresses this by combining PTFE with chemically stable binders—specifically polyvinylidene fluoride (PVDF), PVDF co-polymers, or poly(ethylene oxide) (PEO).

The need for this composite approach is shown by the severe performance penalties of using pure PTFE. The patent states that PTFE has a relatively low Lowest Unoccupied Molecular Orbital (LUMO).

In quantum chemistry, this level acts as a stability threshold; because the LUMO is low, PTFE is "too eager" to accept electrons from the anode. At low operating potentials, charge transfer into the PTFE structure leads to defluorination and the formation of lithium fluoride and polyenes.

Pure PTFE dry electrodes suffer an ICL of about 127 mAh/g. Compared to industry benchmarks—where mature wet-slurry graphite anodes typically show an ICL of only 20 to 35 mAh/g—the pure PTFE performance is nearly five times worse.

This inefficiency makes pure PTFE dry electrodes commercially unviable, as they waste a large part of the battery's lithium on side reactions before the device is used.

To fix this, the patent introduces a composite binder system that mixes PTFE with materials such as PVDF or polyethylene (PE), which have higher LUMO energy levels (greater stability).

These added polymers effectively coat the active materials, creating a barrier that prevents the unstable PTFE from direct contact with the electrode materials.

Performance data shows this method improves dry electrode technology to competitive levels. For example, replacing pure PTFE with a polyethylene binder reduced the ICL to only 30 mAh/g, matching the efficiency of standard wet-slurry electrodes.

Additionally, a PTFE-PVDF composite processed at room temperature achieved an ICL of about 50 mAh/g. While slightly above top-tier wet anodes, this is a huge step up from the pure PTFE baseline, bringing dry processes close to commercial viability.

Most importantly, the patent solves the "throughput nightmare" that has blocked mass production. Dry coating involves calendering—pressing powder into a film using high-pressure rollers. Previously, pure PTFE required ten passes to stick together, which was far too slow for high-volume manufacturing.

The patent notes that the new composite binder allows a cohesive film to form in just three passes. By tripling the manufacturing speed, this breakthrough enables Tesla to meet production targets needed for mass-market vehicles.

Beyond speed and chemistry, the patent also addresses the physical durability of the cathode film. Early dry-cathode attempts had high scrap rates due to "dusting," in which the brittle ceramic powder would crack or turn to dust when wound tightly into the can.

Tesla describes a specific high-shear jet-milling process that fibrillizes the composite binder into a microstructure resembling a 'spiderweb.' This transforms the brittle powder into a flexible, self-supporting film capable of withstanding winding stresses without cracking, turning the dry cathode from a lab experiment into a reliable industrial product.”

This is definitely exciting, and if things work out as Tesla described in the patent, this could be a breakthrough that significantly reduces the production costs of the Cybertruck and the Tesla Model Y, which currently use Tesla’s in-house 4680 cells.

Please let me know what you think in the comments. Share your ideas by clicking the red “Add new comment” button below. Also, be sure to visit our site, torquenews.com/Tesla, regularly for the latest updates.

For more information, check out: A Tesla Cybertruck Owner Says a Shit Of Metal Fell Out Of a Truck In Front Of Him On the Highway & Hit His Cybertruck – He Adds, “Because Of The Stainless Steel & Shatter-Resistant Glass, The Damage Was Minimal”

Tinsae Aregay has been following Tesla and the evolution of the EV space daily for several years. He covers everything about Tesla, from the cars to Elon Musk, the energy business, and autonomy. Follow Tinsae on Twitter at @TinsaeAregay for daily Tesla news.