One upcoming event Tesla (NASDAQ:TSLA) investors have been looking forward to for months is the electric-car maker's "Battery Day." While not much is known about the event, investors and analysts have speculated that the company will unveil improved battery chemistry and possibly enhanced supply commitments from battery partners. Indeed, some analysts have even cited the Sep. 22 Battery Day event as a key reason to be bullish on the growth stock.

Those who were betting on exciting news to come out of the event got some validation on Friday from Tesla CEO Elon Musk himself. "Many exciting things will be unveiled on Battery Day 9/22," Musk said on Twitter Friday morning. 

Manufacturing at Tesla's factory in California.

Tesla factory. Image source: The Motley Fool.

What could Tesla unveil?

We know a few things about what Tesla will likely unveil later this month -- at least based on some teasers from CEO Elon Musk (via Electrek). When Musk was in Berlin, Germany, earlier this month, he said the company's new factory in Berlin would feature "a bunch of innovative stuff," including "a radical redesign to the core technology of building a car." He went on to note that the company will unveil some of what they are working on in Berlin at Tesla's upcoming Battery Day. "It is going to be the first time that there will be a transformation of the core structural design of the vehicle," Musk added. "It's quite a big thing."

Meanwhile, there are rumors that the background image in Tesla's invitation to its Battery Day event may be teasing a new nanowire technology for batteries that could enable 50% higher energy density than standard lithium-ion batteries. 

Finally, it's worth pointing out that Tesla's Battery Day event will be held at a site where the company purportedly plans to work on a secret battery project for a new battery manufacturing system. 

With driving range of up to 402 miles on a single charge for Tesla's flagship Model S and up to 322 miles on its more affordable Model 3, the company's vehicles already have meaningful driving range. Could new battery technology help Tesla push the boundaries even more?

Elon Musk at a product event.

CEO Elon Musk at a Tesla product event. Image source: author.

A boon for Tesla's energy business, too?

Of course, investors shouldn't forget about Tesla's nascent energy business, which consists of solar power and energy storage battery products. The company's energy storage business, specifically, could potentially benefit from battery chemistry improvements. The company deployed 419 megawatt-hours of energy storage capacity during the second quarter, driven by sequential growth in sales of its residential and commercial-scale battery-storage products. 

Long-term, Musk believes the company's energy-storage business can rival its automotive business.

Investors, of course, should still view all of these product rumors as speculation. But if there are any game-changing announcements at Tesla's Battery Day event on Sep. 22, Tesla could further solidify its lead in the electric car market and fortify its position as a force to be reckoned with in the massive energy industry.

This article represents the opinion of the writer, who may disagree with the “official” recommendation position of a Motley Fool premium advisory service. We’re motley! Questioning an investing thesis -- even one of our own -- helps us all think critically about investing and make decisions that help us become smarter, happier, and richer.