Robin Zeng, the chairman of Contemporary Amperex Technology (CATL), the world's largest electric vehicle battery maker, has expressed his skepticism about Tesla's 4680 cylindrical cell technology, stating that it "is going to fail and never be successful."

Zeng's comments come after Tesla CEO Elon Musk's visit to China in April, where the two had a heated debate about the technology. Zeng claims that Musk was silent when presented with the challenges of producing the batteries, suggesting that the Tesla CEO lacks the necessary expertise. Tesla has produced 100 million of the "tabless" 4680 cells, which are used in some of its cars, including the Cybertruck, and are supposed to have five times more energy capacity.

Zeng's criticism also extends to Musk's habit of overpromising timelines, particularly regarding Full Self-Driving technology. The CATL chairman believes that Musk's aggressive deadlines often put undue pressure on his team, citing that "maybe something needs five years, but he says two years." This sparks a larger debate about the feasibility of Tesla's ambitious projects and the potential consequences of overpromising in the EV industry.