The traditional thinking on electric cars: they are hooked up to the power grid to charge, continually replenishing their advanced batteries.

But reversing that flow of energy from vehicles back into the grid could not only power large buildings – it could even improve the cars’ battery life, contends a new study in the journal Energy.

Taking excess energy from an idle electric vehicle actually improves the battery life, based on an algorithm developed by scientists at the University of Warwick.

“Not only is vehicle-to-grid and effective solution for grid support – and subsequently a tidy revenue stream – but we have shown that there is a real possibility of extending the lifetime of traction batteries in tandem,” said Kotub Uddin, the leader of the team, which included engineers from Jaguar Land Rover.

The complex factors that weaken and degrade advanced lithium ion batteries include temperature, age, how frequently and how deeply it is charged and discharged, and other factors.

The scientists developed a “smart gird” algorithm that took all the factors into account – and included how much energy a vehicle requires for daily journeys, and the threshold of how much a battery can spare to the grid without adversely affecting the battery longevity.

They tested their method conceptually, involving the electric cars parked at the Warwick campus. They found that the roughly 2 percent of vehicles parked at the college campus would be able to power the school’s International Digital Laboratory, which includes 360 staff, multiple electrical laboratories, a 100-seat auditorium, and other facilities.

The calculations also indicated that capacity fade in such vehicles would be reduced by as much 9.1 percent. Power fade would be decreased by up to 12.1 percent, they also found.