Trends in Automotive Battery Cell Design: A Statistical Analysis of Empirical Data

Abstract

Lithium-ion (Li-ion) batteries have become the preferred power source for electric vehicles (EVs) due to their high energy density, low self-discharge rate, and long cycle life. Over the past decade, technological enhancements accompanied by massive cost reductions have enabled the growing market diffusion of EVs. This diffusion has resulted in customized and cost-effective Li-ion battery cell designs tailored to automotive requirements. This study describes design trends in Li-ion batteries from the pack to the electrode level based on empirical data, including pack energy, cell capacity, outer cell dimensions and formats, energy density, specific energy, and electrode properties, such as active material selection, porosities, and component thicknesses. Market share-weighted findings imply several trends, such as (1) increasing cell dimensions, with the longest cells reaching 500 mm (pouch) and almost 1000 mm (prismatic) in 2021, (2) increasing differentiation between either high-energy or low-cost cathode and anode materials, and (3) increasing cell energy, equivalent to gaining about 100% (energy density) and 70% (specific energy) compared to the 2010 and 2021 averages. Despite these improvements, this study finds that the widespread market diffusion of the latest cell technologies proceeds slower than industry announcements suggest and that several well-known, literature-proofed potentials are not yet fully exploited.