Game-changing new battery tech promises near-instant charging—but the leap forward may come with big hurdles.

Eunice Lee, the Asian autos analyst at Bernstein, an investment research company, cited Chinese rivals XPeng and Zeekr, whose respective 5C and 5.5C charging systems can add about 280 miles and 342 miles of range in 10 minutes. She was “generally impressed” by BYD’s claims, after it had lagged behind rivals.