BEIJING (Reuters) - China's Xpeng Motors and Volkswagen have agreed to expand their partnership to cooperate on ultra-fast electric vehicle charging networks in China, the automakers said on Monday.

The companies have signed a memorandum of understanding to open their respective fast-charging networks to each other's customers, which comprise more than 20,000 charging piles across 420 cities in China, they said in a joint statement.

They will also explore the joint construction of co-branded ultra-fast charging stations.

Xpeng and Volkswagen forged a partnership in 2023, when Volkswagen bought 4.99% of Xpeng for around $700 million with plans to jointly launch two Volkswagen-branded EV models by 2026.

Volkswagen later said it had developed a new architecture for intelligent and electric cars with Xpeng which the German automaker said would help it offer more affordable EVs in its biggest market.

(Reporting by Joe Cash and Brenda Goh; Editing by Kim Coghill and Saad Sayeed)