BMW Group’s joint venture with SGL Group will spend $200 million to triple the production capacity of its carbon fiber products. The factory, based in Germany, will become the world’s largest producer of carbon fiber, with an annual output of 9,000 tons by 2015 when the expansion is completed. The plant provides carbon fiber reinforced plastics for BMW’s family of i electric and plug-in hybrid cars — the i3 electric compact car and the i8 plug-in hybrid sports car. The i3 went on sale in the United States this month and the i8 is to launch in August. The carbon fiber has been used to produce 5,000 i3 cars at BMW’s factory in Leipzig, Germany, which has a daily output of 100 vehicles. The redesigned 7-series flagship sedan due in two years is expected to make extensive use of carbon fiber. The plant, which opened in 2010, uses only hydroelectric power provided from Moses Lake.