With the launch of a much-hyped and against-the-odds electric car, Xiaomi SU7, Lei Jun, Xiaomi’s co-founder and CEO, is taking on Elon Musk with a strategy that takes a page from Tesla’s playbook. Lei, 54, took the stage in Beijing on Thursday to unveil Xiaomi’s SU7 car, a project three years in the making that has attracted a lot of attention but which, Lei has warned investors, will lose money.