BYD has a foothold in export, mostly for the E6 taxi. They also are low cost battery producers, but thus far have concentrated on cheap rather than energy dense. However their big story is busses, which are pretty good and are the major value producers today.
I think BYD represents a good enough fling that I found their ADR's good speculations. Take a quick look at the long chart and you'll see little overall movement other than the 'Buffet Bounce', but with typical volatility and modest float. If you choose to buy and hold you'll be betting on a strong future for them, including solar power and energy storage. Their intention has been to be a Chinese national Tesla, philosophically, but not in market positioning.
Maybe this will be wise, but I'm happy to wait and watch, expecting to make money long term.
Context: I buy and hold, including speculations like BYD. Long term that has worked very well but I never buy anything I don't think I understand.