Elon Musk promises Tesla will make a lower-cost electric vehicle by 2023 on Tesla’s annual battery day, but the goal hinges on a new, more affordable battery that some experts are questioning.

Musk also predicted that the company would “do really pretty well in 2020.”

Tesla’s stock price has risen over 400% this year, from $86.14 to $448.16 at closing Oct. 1. Musk sounded very confident that Tesla is heading to a good future, saying the company “will be worth more in five years” in a New York Times podcast after the battery day.

But experts say Musk may be too confident about Tesla’s future, especially after a battery day that disappointed the public because Tesla will not yet be able to produce affordable batteries in high volume.

“Ninety percent of the event wasn’t about things that people needed to know at the consumer level,” wrote Fred Lambert, editor-in-chief of ElectrekCo, a news website on electric vehicles, in an article about Tesla’s battery day. “It’s just about one component inside a product (sure, an important component) but it’s still a component for the average consumer.

Actually the day before the battery day, Musk had tweeted an important note that it will be 2022 before Tesla reaches high-volume production of its new type of battery cell– not a good sign.

“The uncertainty of mass adoption by consumers causes us to wait to award a moat,” wrote David Whiston, sector strategist at the financial services firm Morningstar Inc., referring to a competitive advantage. “Some consumers may be afraid to not have their vehicle ready in an emergency if it is still charging, and range is another important matter beyond the numbers.”

As an electric vehicle company, Tesla is still not the main option for customers in the traditional auto industry because its cars require charging stations and its prices are higher.

“We do not see it having mass-market volume this decade,” Whiston wrote in his latest report. “Tesla’s product plans for now do not mean an electric vehicle for every consumer who wants one, because the prices are too high.”

“It is important to keep the hype about Tesla in perspective relative to the firm’s limited, though now growing, production capacity,” he added.

Tesla is also facing big challenges from its rivals, such as Ford Motor Company, General Motors, and Honda Motor Company. Especially in China, where Tesla has a large factory and a huge potential market. William Li, chief executive officer at NIO Inc., an electric-vehicle company based in Shanghai, told Bloomberg that battery costs had been declining throughout the industry.

“I believe the overall battery cost decrease will help promote electric vehicles,” he added.

Li also pointed out that the “quality and service will be the biggest challenge for all automakers in rapid expansion.”

On Twitter, Musk expressed his dissatisfaction about how the media portrayed the battery day as disappointing: “I wasn’t trying to convince people that much — the results will speak for themselves,” he wrote. Experts said Tesla would have growing pains, recessions to fight through before reaching mass-market volume, more competition, and debt to pay off.