In the past 30 years, the cost of rechargeable lithium-ion batteries for mobile phones, laptops and automobiles has dropped significantly and become the main driving force for the rapid growth of these technologies. However, attempts to quantify the results of cost reduction are ambiguous and contradictory, which hinders attempts to predict the future of the technology or design useful policies and research priorities. Now, researchers at MIT have carried out a detailed analysis of the research on the price decl