Could China, the world's largest automobile market, help address the threat of global warming if it went completely electric? The answer isn’t as obvious as it seems. China has been making great strides toward electrification. Electric vehicle sales are booming: Consumers bought more than 300,000 last year, and more than 5 million are expected to be on the road by 2020. The government just announced bold plans for a wave of big new battery factories.