What happened

Shares of Tesla (TSLA 0.38%) are on a tear Monday, rising 8.5% in late morning trading as of 11:55 a.m. EDT. But if you ask me, the reason these shares are rocking dates back to last week -- or at least the weekend just past.

Or perhaps I should say reasons.

Lithium Ion Battery graphic

Image source: Getty Images.

So what

There are actually two catalysts that are driving Tesla forward today. First, on Friday, Elon Musk teased investors with a cryptic Tweet promising that "many exciting things will be unveiled" at the company's upcoming Battery Day presentation, slated to take place on September 22.

No one's 100% sure just what Musk was referring to there, but hypotheses range from big reveals on changes to car production in Berlin to a new "nanowire technology" that Tesla has invented for building batteries with 50% higher energy density than is currently possible.

Now what

Granted, Musk's Battery Day tweet came out Friday, and the stock didn't move much in response to it -- rising less than 1% in Friday trading. But over the weekend, there was more news to intrigue Tesla investors, as well as investors in electric cars, generally.

On Saturday, OilPrice.com reported on the contents of a new report out of mining research and consultancy firm Wood Mackenzie. In said report, the consultant discussed the world's need for 800,000 new tons of lithium production by 2025 -- and also explained why all this new lithium will be needed. Woods' analysis of current trends in global warming and electric vehicle production "brings electric vehicle (EV) uptake forward by ten years and sees EVs make up around 40% of passenger car sales by 2030."

"This considerably accelerates the demand for batteries and the raw materials that go into them," observes the analyst. It also suggests that Tesla's sales over the next five years could be a whole lot stronger than investors had been anticipating.

Is this reason enough for a stock rally at Tesla? Investors seem to think so today.