Tesla announced plans Wednesday to raise at least $1.6 billion in debt to finance the expansion of its electric car business, develop its upcoming mass market vehicle and build the company’s much anticipated battery plant. The Palo Alto, Calif., company separately released additional details about its plans for the so-called Tesla Gigafactory on its corporate blog, saying it will produce more lithium ion batteries in 2020 than the total global output last year. The factory promises to address one of the company’s critical challenges, a supply crunch for batteries that constrains its ability to meet demand for its vehicles. It should also drive down production costs. “As we at Tesla reach for our goal of producing a mass market electric car in approximately three years, we have an opportunity to leverage our projected demand for lithium ion batteries to reduce their cost faster than previously thought possible,” the company said in a statement.