BYD, the world’s largest electric vehicle maker, unveiled a series of technology advances, including what it calls China’s first automotive-grade 4-nanometer chip for self-driving cars.The semiconductor breakthrough approaches the lead of Chinese tech giant Huawei Technologies, which currently makes chips with a geometry of 7 nm but has pledged to debut 1.4 nm chips by 2031. It’s designed to allow BYD’s computer-assisted driving to stand out from a crowded Chinese EV market that includes rivals such as Xpeng and Xiaomi.Facing eight months in a row of falling sales and intense competition for more advanced charging and intelligent driving technologies, BYD…