South Korean energy company SK Innovation said it had acquired a minority stake in a Chinese EV battery swap service, according to local reports, as it looks to strengthen its foothold in the world's largest electric vehicle (EV) market.

SK Innovation, a major global manufacturer of EV batteries, is said to have acquired a 13.3% stake in Beijing-based Blue Park Smart Energy Technology (BPSE) which is controlled by local automaker [and Daimler and Hyundai JV partner] Beijing Automotive Group.

BPSE operates battery swap stations for electric taxis in Beijing, allowing drivers to avoid waiting for their cars to be recharged. Battery swapping companies are expected to help lower the initial purchase price of electric vehicles by allowing buyers to finance the batteries separately.

SK Innovation already has a battery manufacturing joint venture with Beijing Automotive, which began operations in 2013. Its Chinese partner also controls local commercial vehicle manufacturer Beiqi Foton Motor and has major vehicle manufacturing joint ventures with western automakers.

SK Innovation said it planned to establish a 'Battery as a Service' business in China, providing EV owners with services such as battery rental, recharging and recycling. 

Around 1m new battery-powered electric vehicles were sold in China last year and analysts expect annual sales to exceed 5m by 2025, based on central government targets.