A hidden partnership between Apple and Chinese automaker BYD has come to light, revealing a years-long effort to co-develop long-range EV battery technology. The breakthrough batteries now power BYDs electric vehicles,

Apple (NASDAQ:AAPL) and Chinese automaker BYD (OTCPK:BYDDF) worked secretly for years as part of the technology firm’s now-canceled car project, Bloomberg reported, citing people familiar with the situation.

The details, which remained under wraps until now, come from people familiar with the situation who spoke to Bloomberg. According to the sources, the iPhone maker