Why some EV researchers are skeptical of BYD's fast charging tech

Chinese auto maker BYD's new 5-minute EV charging technology might be one of the biggest breakthroughs the industry has seen so far. But experts say there's reason to temper enthusiasm. Still, BYD has gone from low-cost battery maker to global automotive giant in a short time. Its ability to innovate shows just how far ahead Chinese auto makers are compared with global rivals, including American Tesla.