Elon Musk hints at major capacity increases as Tesla Battery Day approaches

Something's stirring over at Tesla . The company's highly anticipated Battery Day is just on the horizon, and ahead of the event, CEO Elon Musk shared some insight into energy density via Twitter.

Replying to a Twitter thread surrounding the possibility of an electric airplane, Musk said batteries with 400 watt hours per kilogram are highly likely in the next three to four years. And not just one-off units, either, but mass produced batteries with long lifecycles, too.

This type of energy density could provide 50% more energy density compared to today's batteries, noting today's batteries used in the Tesla Model 3 feature an energy density of about 260 Wh/kg. The more energy packed into a battery, the longer the driving range for a vehicle.

In conjunction with Musk's comments, Tesla itself released a teaser showing a peculiar pattern with numerous dots. Reuters reported the pattern could hint at silicon nanowire anode, which if realized, could help Tesla achieve more energy dense batteries with longer usable lives. Tesla did not immediately respond to a request for comment.

This year's been rife with speculation surrounding Tesla battery news. From Panasonic's pledge to boost energy density in the years to come, to China's CATL's work with Tesla on a "million-mile" battery, there's been no short supply of energy-related news. Tesla also applied to become a utility provider in the UK earlier this year, just as we learned more about the company's Autobidder system to manage their energy production and sell electricity back to the grid.

We've got less than a month to go before Battery Day kicks off on Sept. 22, and we'll surely hear more before then. Musk likes to share on Twitter. A lot.

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First published Aug. 25.