The "BYD" name is the pinyin initials of the company's Chinese name Biyadi, which itself was created from company's original trademark Yadi Electronics (亚迪电子, named after the Yadi Road in Dapeng New District, where the company was once based) and the character Bi was just conveniently added to give the company an alphabetical advantage in trade shows.
The company later back-formed a slogan, "Build Your Dream", or more commonly "Build Your Dreams"
with an automotive subcompany: https://en.wikipedia.org/wiki/BYD_Auto
2024 BYD Seal Performance review: https://www.drive.com.au/reviews/2024-byd-seal-performance-r...
As for the company name:
https://en.wikipedia.org/wiki/BYD_Company#Name