German carmaker Mercedes opened a new battery factory in the southern US state of Alabama on Tuesday, a key part of its plans to ramp up production of electric cars in the US. Chief executive Ola Källenius called it a “milestone” as he opened the factory, which is adjacent to an existing car plant. In a few months, the two plants will churn out EQS and EQE models of the company’s sport utility vehicles (SUVs). The focus on electric vehicles is part of a corporate offensive to bring eight fully electric vehicles to market, produced in seven different sites. Facilities in Alabama have long been …