Tesla Secretly Acquired Battery Startup SilLion

Tesla has secretly acquired Colorado-based battery startup SilLion Inc which has a new patent for silicon-based battery anode. Tesla had been widely rumoured to have acquired the startup based out of Colorado but this was only recently confirmed. These rumours started when the employees of the startup were hired by Tesla and the carmaker started listing jobs in Colorado where it previously didn't have R&D operations.

"Developer of an advanced lithium-ion battery designed to address the market's accelerated demand for higher performance energy storage devices. The company's technology delivers high-energy batteries by simultaneously incorporating high-loaded silicon anodes, nickel-rich NMC cathodes, and a non-flammable ionic liquid electrolyte and offer an increase in both energy density and specific energy in lithium-ion batteries, enabling users to get safer and lower-cost energy storage devices for defense, consumer electronics, and electric vehicle applications," said SilLion on its website before it shut down.

The startup had received several grants from the US Department of Defense and the US Department of Energy before it went dark in 2018. Around that time, three of the company's researchers changed their job descriptions and positions to Tesla but its co-founders Tyler Evans and Daniela Molina Piper never made the change.

These new batteries were announced at its battery day event last year

One of the most important patents that SilLion most important patents is called the "Large Format Battery Anodes Comprising of Silicon Particles."

"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," wrote Evans and Piper in their patent filing.

This is something Tesla has now confirmed in its battery day event stating that its new 4680 batteries have an anode by new silicon. Tesla has just started a new anode production line in the Gigafactory in Texas. This doesn't mean that Tesla's new batteries have just been enabled by the acquisition of SilLion, but they have played a major role in its creation.