As reported by Bloomberg on Wednesday, Apple has worked closely with Chinese automaker BYD. Both companies reportedly reached an agreement around 2017 to build batteries using lithium iron phosphate cells (LFP). The technology would significantly increase the autonomy of the car and was also considered safer than typical electric vehicle batteries.

Several patents behind the Apple Car program were previously leaked to the public, further corroborating the leaks and rumor behind it, but the public was not treated to seeing an actual prototype or even a confirmation that it existed.

Apple worked with a Chinese automaker for years to design a battery system for its now-canceled car project. That’s according to Bloomberg, which reports that Apple was collaborating with BYD Co., a Shenzhen-based car company,