Tesla has introduced a groundbreaking redesign of its 4680 battery cell, replacing conventional current-collecting tabs with a continuous metal foil hem. The patent, published on July 14, 2026, aims to streamline manufacturing, reduce internal resistance, and improve safety—key factors in Tesla’s push to lower battery production costs.
Redesigning the Current Collection System
Traditional cylindrical lithium-ion batteries, including Tesla’s 4680 and Panasonic’s 2170 cells, rely on a jelly-roll structure where electrodes are wound into a spiral. Current is collected via tabs—metal strips attached to the electrodes—which force electrons to travel longer distances, increasing resistance and localized heating. Tesla’s new patent eliminates these tabs by folding the uncoated edges of the metal foil inward to form a continuous hem. When wound, this hem aligns with adjacent layers, allowing the entire electrode edge to participate in current collection.
This structural change shortens electron pathways, reducing internal resistance—a critical factor in battery efficiency and heat management. According to Tesla’s patent filing, the hem design also simplifies manufacturing by removing the need for tab processing, cutting, slotting, and debris handling. The company states that this could lower equipment complexity, energy consumption, and labor requirements while accelerating electrolyte filling, a known bottleneck in high-volume battery production.
Compatibility and Safety Enhancements
Unlike chemical modifications, Tesla’s patent focuses solely on the current-collection architecture, ensuring compatibility with existing cathode chemistries, including lithium iron phosphate (LFP), nickel manganese cobalt (NMC), and nickel cobalt aluminum (NCA). The design is also adaptable to both wet and dry electrode manufacturing processes, making it versatile for different production lines.
Safety is another key benefit. The hem structure expands internal space, providing larger channels for venting gases during thermal runaway—a critical safety feature for high-energy-density cells. Tesla’s internal simulations suggest the design could further improve fast-charging performance by reducing resistance, though real-world validation in mass production remains pending.
Manufacturing and Market Implications
The patent highlights Tesla’s strategy of refining structural design rather than pursuing chemical breakthroughs to achieve cost reductions. By eliminating multiple manufacturing steps, the hem design could significantly lower production costs, though Tesla has not disclosed specific figures comparing the new method to its existing processes. The global applicability of the patent and potential responses from competitors like Panasonic and LG Energy Solution—both of which supply cylindrical cells with traditional tab designs—remain unclear.
While the innovation signals Tesla’s commitment to in-house battery development, its real-world impact will depend on the company’s ability to scale the hem design. If successful, the tab-free structure could set a new standard for cylindrical battery production, further solidifying Tesla’s position in the electric vehicle market.
