Robin Zeng, the founder of the worlds largest EV battery company, says Tesla CEO Elon Musks big bet on 4680 cylindrical cell technology is going to fail and never be successful. Zeng, the chairman of Chinas Contemporary Amperex Technology (CATL), tells Reuters that when Musk visited China in April, We had a very big debate, and I showed him. He was silent. He doesnt know how to make a battery.Teslas tabless 4680 cells, which are used in some of its cars, including the Cybertruck, are supposed to have five times more energy capacity, and the company announced in September it had produced 100 million of them. A recent report by The Information said Musk had given the team working on the batteries an end of the year deadline to deal with costs and other problems.CATL batteries, meanwhile, go inside everything from Tesla vehicles in China to Ford EVs in North America like the Mustang Mach-E and F-150 Lightning. The company specializes in lithium iron phosphate batteries (LFP), which generally dont get as much range as various cylindrical cell units used in many Tesla vehicles. While Zeng wasnt impressed with Musks battery knowledge, he thought he was good with chips, software, hardware, and mechanical things.Zeng also commented that Musks problem is overpromising timelines, which he often does habitually, especially regarding Full Self-Driving technology. Maybe something needs five years. But he says two years. I definitely asked him why. He told me he wanted to push people.