Tesla CEO Elon Musk warned about "high volume production" and the Battery.
According to Elon Musk's statements on Twitter, anything revealed during the event will not enter mass production until 2022.

That timescale means the technology will primarily impact Tesla's Semi, Cybertruck and Roadster , the CEO said, adding that the company will continue to buy third-party batteries even if it decides to make its own.
Elon Musk's comments suggest that any new battery technology shown off at today's event will be in the prototype stage, ruling out its imminent use in current mass-market vehicles like the Model 3 or Model Y.
His statements also make it clear that Tesla will still need to buy third-party batteries in the coming years, even if it starts making its own.
«We plan to increase, not decrease, our battery purchases from Panasonic, LG , and CATL (and possibly other partners). However, even with our suppliers going full speed, we still anticipate significant shortages in 2022 unless we take action ourselves.»
Shortages affected the electric vehicle company in 2018, when Elon Musk said a battery shortage at Panasonic limited Model 3 production.

There has been a lot of speculation about what Tesla might announce at its Battery Day event. Leaks, research, and tweets from Musk suggest that it could announce a new battery technology that has a higher capacity than others and can be produced at a lower cost.
"It's going to be crazy," Elon Musk promised.
The reports also mentioned the so-called "million-mile" battery, which could allow the company to sell its cars cheaper and give customers confidence that electric vehicles will last longer.
