Tesla Acquired Battery Startup SilLion, Reveals Patent Filing

Tesla recently filed a patent for a new silicon-based battery anode, confirming that the electric vehicle (EV) manufacturer actually did acquire Colorado-based battery technology startup SiILion, Inc., as many had speculated over the last few years — reports Electrek.

Tesla was rumored to have acquired the startup after the EV maker hired a few of its employees, and three of its researchers changed their job positions to Tesla.

SiILion, Inc. had scored several grants from the U.S. Department of Defense and U.S. Department of Energy, and was working on a new high-energy density battery chemistry based on “high-loaded silicon anodes before dropping off the map in 2018.

One of the battery startup’s most important patents, Large-format Battery Anodes Comprising Silicon Particles, now lists Tesla, Inc. as the applicant, and credits SiILion, Inc. co-founders Tyler Evans and Daniela Molina Piper as the inventors.

Here’s a description of the anode technology from the patent’s abstract:

Large-scale anodes containing high weight percentages of silicon suitable for use in lithium-ion energy storage devices and batteries, and methods of manufacturing the same, are described. The anode material described herein can include a film cast on a current collector substrate, with the film including a plurality of active material particles and a conductive polymer membrane coated over the active material particles. In some embodiments, the conductive polymer membrane comprises polyacrylonitrile (PAN). The method of manufacturing the anode material can include preparation of a slurry including the active material particles and the conductive polymer material, casting the slurry on a current collector substrate, and subjecting the composite material to drying and heat treatments.

The discovery confirms what Gali from HyperChange first speculated back in February 2020:

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At its Battery Day event last year, Tesla announced that its new 4680 battery cells use a new silicon-based anode. In hindsight, this technology was likely made possible by the EV maker’s SiILion, Inc. acquisition.

This isn’t the first time Tesla has gone the acquisition route to improve its battery technology — earlier this year, the company acquired Canadian battery startup Springpower International for its cathode designs.