The market for electric vehicles is absolutely massive. It's projected to reach north of $25 billion by 2027, from roughly $4 billion in 2019. Key to this growth, however, is battery innovation. On this front, we are seeing breakthroughs in solid-state technology ("glass" batteries), "tabless" batteries from Tesla, and even novel ways of using renewable natural gas as a power source. In this section, we'll discuss how you should think about battery stocks as a part of your investing strategy.