Complex sentence: The Model S was the world's best-selling plug-in vehicle in 2015, and its global sales achieved the 150,000 unit milestone in November 2016, four years and a five months after its introduction.
Split into simpler sentences: The Model S was the world's best-selling plug-in vehicle in 2015. Its global sales achieved the 150,000 unit milestone in November 2016, four years and five months after its introduction.