Volkswagen is in talks to sell a stake in its electric vehicle charging unit Electrify America, as they look for outside funds to build infrastructure for battery-powered cars. Volkswagen is working with Citi to look for a co-investor prepared to invest $1 billion into the division.

Electrify America plans to spend $2 billion in the 2017-2026 period to expand charging stations for electric vehicles (EV). The unit, whose main rivals are ChargePoint and Tesla’s Supercharger, has 635 charging stations with around 2,850 fast-loading spots up and running, according to its website.

This includes ultra-fast high-speed of up to 350-kilowatt charging stations allowing owners to charge their cars in under 20 minutes. The company expects to install about 800 charging stations with about 3,500 fast chargers by December 2021, expanding to 45 states. It also operates solar-powered charging stations.

At Volkswagen’s Power Day in March, Electrify America Chief Executive Giovanni Palazzo said that the group was planning to expand further. The carmaker will present its new strategy on July 13. It is currently trying to connect its various charging efforts under the Charging & Energy business area led by Elke Temme, a long-time executive at Germany’s top utility RWE.