Electric vehicle (EV) battery maker CATL has invested in China’s EV startup Aiways, according to an official corporate registration filing.

It is unclear how much Shanghai-based Aiways, which was founded in 2017, has raised from CATL. Aiways declined to comment on the investment but said it would work on battery technologies with CATL.

China’s ride-hailing giant Didi Chuxing has also invested in Aiways, which is making cars in China’s eastern city of Shangrao and sells them in China and Europe.

CATL, which earlier invested in another startup Byton, did not immediately respond to a request for comment.