 According to the Society of Automotive Engineers ( SAE ) definitions , the Volt is a plug @-@ in hybrid vehicle , due to the combination of an internal combustion engine and two electric motors , along with a battery that can accept off @-@ board energy . The Volt operates as a purely electric vehicle for the first 25 to 50 miles ( 40 to 80 km ) in charge @-@ depleting mode . When the battery capacity drops below a pre @-@ established threshold from full charge , the vehicle enters charge @-@ sustaining mode , and the Volt 's control system will select the most optimally efficient drive mode to improve performance and boost high @-@ speed efficiency . 
