Tesla Has Been Using New 4680 Batteries for Months, Musk Says

For some, Tesla Inc's TSLA battery day was a letdown: the technology sounded great, but it's still several years away, and Tesla did not have an onstage demo. 

Now CEO Musk has said in a tweet that the new 4680 cells have been used in prototype vehicles for months.

While the vehicle models are unknown, a safe guess would be the Plaid Model S demonstrated on-screen at the event. 

Benzinga's Take: This is great news. The fact that Tesla has been using the batteries for months mean they work well enough for Tesla to feel confident in sharing that they are coming.

The last concern would be longevity, but there are laboratory testing methods to speed up battery degradation to find an estimated battery lifespan. 

Photo from Tesla Battery Day presentation.