Tesla (NASDAQ:TSLA) CEO Elon Musk threw some cold water on investor excitement leading up to the automaker's Tuesday evening battery event, warning the company's new technologies will take time to scale.

Tesla shares are up 115% over the past three months in part on growing anticipation about what will be announced at the company's battery event. Investors are hoping that new, improved batteries and manufacturing processes can give Tesla a competitive advantage against a slew of new electric vehicle competition from traditional automakers and start-ups.

A Tesla Model Y driving outside of an urban area.

Image source: Tesla.

Tesla is also shifting away from individual parts riveted together on an assembly line and to a single component made using the world's largest aluminum casting machine. Musk has long talked of generating cost savings by automating the entire production line, which in years past he referred to as an "alien dreadnought" that would help him to reinvent auto manufacturing processes.

But on Twitter Monday night, Musk noted how difficult it is to quickly scale up to mass production, saying he does not expect the products to be announced to hit mass production until 2022.

"The extreme difficulty of scaling production of new technology is not well understood. It's 1000% to 10,000% harder than making a few prototypes," Musk wrote in a follow-up tweet. "The machine that makes the machine is vastly harder than the machine itself."

Though Musk says the challenges Tesla faces are not well understood, his words likely ring true to other automakers. Car companies typically spend years prototyping new designs to work out manufacturing kinks before reaching mass production.

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