EVwire brief: Tesla has published two wireless vehicle charging patents that detail core technologies behind the Cybercab's inductive charging pad. Both were filed in 2024 and recently appeared on public patent databases.
The first patent describes a single wireless charging pad design that can be wired during manufacturing to work with both 400V and 800V battery packs, eliminating the need for a separate voltage converter. The second covers a foreign object detection system that embeds hundreds of tiny temperature sensors directly into the pad's circuit board to catch overheating metal objects and automatically cut power.
The patents were shared by industry watcher Sawyer Merritt on X:
How the dual-voltage pad works
Traditional wireless chargers that need to support different battery voltages require a separate DC/DC converter to bridge the gap. Tesla's patent sidesteps that by using the same set of transistors, coils, and resonant capacitors but wiring them in one of two configurations during manufacturing.
A 400V battery pack gets an H-bridge layout. An 800V pack gets a stacked half-bridge. The components are identical. Only the connections on the board differ, set by jumpers or electrical connectors at the factory.
The result is one pad design that covers Tesla's full vehicle lineup without adding weight, cost, or conversion losses. The patent also describes optional bidirectional shorting switches that reduce electromagnetic interference and improve efficiency.
Here’s the patent:
How the safety sensors work
The second patent tackles a specific hazard with wireless charging: metal objects stuck between the ground pad and the vehicle. A coin, a bolt, or a scrap of foil sitting in the magnetic field can heat up fast.
Tesla's solution packs dense arrays of bimetallic thermocouples, made from copper and constantan, between the layers of the charging pad's printed circuit board. Because the sensors are sandwiched inside the board rather than mounted on top, they don't eat into surface area needed for other components.
The patent describes configurations with 500 or more sensors spread across the pad surface, enough to detect metallic objects as small as 50 mm. When one heats up, the processing circuit kills power transmission immediately.
Here’s the patent:
Context:
Tesla's Cybercab is already much closer to deployment than it might appear. An EPA certification filing lists the two-seat robotaxi with a 219-hp front motor, an estimated 48-kWh battery and 418 miles (673 km) of equivalent all-electric range. Tesla received its Certificate of Conformity for the 2026 Cybercab in May, with an introduction-into-commerce date of May 29.
That means the Cybercab does not need wireless charging to be deployed. A conventional charging setup could get the vehicle onto the road, while wireless charging could be added as Tesla's robotaxi infrastructure matures.
Tesla also appears to be building charging sites that could fit this kind of fleet operation. The proposed 124-stall V4 Supercharger site in San Francisco, for example, is unusually focused on charging throughput rather than amenities. Its stripped-down design has led members of the EV community to speculate that it could support Tesla's Robotaxi network, although Tesla has not said that is the site's intended purpose.
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