Chinese electric car startup Nio said it is planning to build 4,000 battery-swap stations across the globe by 2025.

It has over 1,000 such stations across the country, of which 256 are along expressways, said the Nasdaq-listed carmaker on Wednesday.

Usually, it takes car owners less than five minutes to get their empty batteries swapped for new ones, said Nio.

Nio statistics show that battery-swap is becoming the predominant way for its car owners, with over 52 percent of its car owners in June relying on the service instead of charging to extend the mileages of their vehicles.

The startup said Nio owners have swapped 10 million batteries at its stations, and 75 percent of these owners have used the service at least once.

Besides Nio, carmakers including BAIC as well as battery maker CATL are exploring the segment as well.

Dozens of models are now capable of battery-swap. Their combined sales in the first four months this year reached 42,000 units, up 54 percent year-on-year, according to battery website GG-LB.

There were 1,519 battery swapping stations across the country by the end of May, according to the China Electric Vehicle Charging Infrastructure Promotion Alliance.

Analysts at Founder Securities estimate that there will be 3.2 million battery-swap cars across the country by 2025, with more than 28,000 power stations.