The quickest and simplest way to benchmark cells against one another is through the comparison of datasheets and rapid standardised testing of cells. However, typical datasheets provide information based on cells tested under constant current load profiles in controlled ambient temperature. These test conditions are unrepresentative of most real applications.
This work selects and benchmarks six 21700 cylindrical cells under four different test categories and two cooling conditions, to determine if relative performance of cells at beginning of life translates from standardised current and thermal conditions to more realistic currents and conditions [1]. Cells were tested under two cooling strategies (natural convection and base cooling) and four different types of loads: constant current discharge, constant C-rate discharge, high-rate constant C-rate cycling, and a simplified set of drive cycles.
Beginning of life performance, characterised by cell usable capacity and maximum surface temperatures/gradients, is known to change significantly across the different cooling and load types. The percentile-based ranking analysis performed in this study, however, illustrates that the cells change their ranking compared to one another significantly, depending on these conditions. Differences in cooling are shown to affect ranking by up to 20%, and differences in load type can affect ranking by up to 98%. This means that some cells perform better under one combination of cooling and load type, and others perform better under a different combination. Importantly, this suggests that the assumption that the cell that performs best in standardised conditions will perform best under the real application, is false.
This work is most impactful to battery pack engineers and manufacturers, as well as researchers running cell level testing for pack applications or models. This work helps stress the importance of running bespoke, relevant testing to choose the best cell and generate more application-relevant cell-level results.

Reference:
[1]: M.W.J. Marzook, J. Eaton, M.A. Samieian, Y. Patel, G.J. Offer, M. Marinescu, The effect of test conditions on the relative performance of cylindrical lithium-ion cells, J. Energy Storage, 105 (2025), 114485, https://doi.org/10.1016/j.est.2024.114485.