An analysis of EV and battery sales data from 13 countries from 2013 to 2020 reveals that practical production experience, or "learning by doing," has driven a significant 42% reduction in battery costs, surpassing the impact of technological advancements and economies of scale. China's domestic content requirements for EV subsidies have allowed local firms like BYD and CATL to rapidly scale up production and lower costs more quickly than international competitors.