Gas stations are a lot bigger these days, and there’s a new reason for them to keep growing: electric vehicles.

As battery-powered cars become more common on roadways, more gas stations are installing chargers alongside old-fashioned pumps. But E.V. charging takes time, so gas station operators are turning their stores into shopping centers where people can spend time — and money — while they wait for cars to charge.

Doing so often means supersizing the business. Buc-ee’s, which has 51 locations primarily in the South and is working with Mercedes-Benz to offer E.V. charging, has stations as big as 75,000 square feet.

“What you are seeing is retailers preparing for what is to come,” said Kevin Hart, the chief sales officer at Upside, which works with retailers, including convenience stores and gas stations, to offer customers rewards on their purchases.

“The last thing they want is you coming, plugging in your car to an E.V. charging station and sitting in your car, so they have to create a shopping experience,” Mr. Hart said. “That is not how they thought 15 years ago.”