Ahead of Tesla’s Battery Day event on Tuesday, September 22, CEO Elon Musk Monday explained via Twitter that while Tesla plans to increase battery cell purchases from Panasonic, LG, CATL, and perhaps other partners, it still anticipates battery shortages starting in 2022 “unless we also take action ourselves.”

At the event, Tesla is expected to showcase what’s been rumored for a long time: a combination of technological developments that help produce batteries that are more energy-dense, last longer, and are cheaper—and easier—to make.

In 2019, Tesla bought ultracapacitor specialists Maxwell Technologies, and it purchased Canada’s Hibar, a battery maker that was linked to lithium-ion battery researcher Jeff Dahm, who was involved in Tesla’s “million-mile battery” skunkworks project. That project, working out of a facility near Tesla’s Fremont factory, has reportedly resulted in a cell capable of lasting three times the cycles of Tesla’s current cells.

Tesla factory, Fremont, California

Tesla factory, Fremont, California

Neither Musk nor Tesla has confirmed that what’s to be revealed at Battery Day directly relates to those developments. But in Tesla’s Q2 financial update call, held in July, Musk noted that it was transitioning some Model 3 production to lithium iron phosphate (LFP) cells so that it might save more of its higher-energy-density cells for the Semi, as production ramps up for 2021 deliveries. 

Musk’s pre–Battery Day comment confirms that the Cybertruck and Roadster may also be privy to the new state-of-the-art cells. They’re all examples of the imperative to keep weight down but energy up. Excess weight means reduced payload for a pickup, and can blunt the performance of a sports car.

Tesla Cybertruck live unveiling - November 21, 2019

Tesla Cybertruck live unveiling - November 21, 2019

Set to be streamed directly after Tesla’s annual shareholder meeting, the event will likely follow the format of the company’s Autonomy Day held in April 2019. Expect to get some background on the company’s current technology, a glimpse of what it’s working on behind the scenes, and a tease of future products and, perhaps, vehicles to come. And leave room for at least one bombshell surprise that months of speculative reports have missed. 

Battery Day will be missing one key executive in Tesla's present-day battery strategy. JB Straubel, who left the company in summer 2019, is widely assessed as one of the world's top experts in EV battery tech.

Tesla CTO JB Straubel and CEO Elon Musk presenting at gigafactory tour, Reno, Nevada, July 2016

Tesla CTO JB Straubel and CEO Elon Musk presenting at gigafactory tour, Reno, Nevada, July 2016

Earlier this year, in what’s essentially become a meme of its own, Musk said that Battery Day is going to “blow your mind.” Then just earlier this month, he again fed the hype machine, with claims that Battery Day “will be very insane.”

That said, Musk faces an unusual kind of challenge: He needs to sell investors on the long-range viability of the rapidly expanding global EV maker, while discouraging many fans and prospective buyers to postpone upgrades and purchases until the new technology has arrived. That's a fine line, and Musk is generally not one to keep to finely crafted talking points.

You can check out the Battery Day presentation here, after the company’s 1:30 p.m. PT meeting concludes.