Europe’s largest automaker, Volkswagen AG, plans to invest $700 million in Chinese electric vehicle manufacturer, Xpeng Inc.(NYSE:XPEV), as it tries to stem a sales decline in its pivotal Chinese market, Bloomberg has reported. VW will eventually hold a nearly 5% stake in Xpeng through capital increases with the company’s Audi premium brand looking to deepen ties with Volksawgen’s long-term partner SAIC Motor Corp Ltd. "The objective of the strategic technical collaboration is to leverage each other’s complementary…