BMW AG is launching two new attacks on one of the biggest obstacles to broader acceptance of electric cars such as its i3 model: the lack of fast recharging stations.

The company plans to announce today a deal with NRG Energy Inc. to allow owners of BMW i3 electric cars to recharge their batteries for free through 2015 at NRG eVgo charging stations in California. The free fast-recharging offer responds to rival Tesla Motors Inc.’s…