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The 18650 and 21700 cell format are state of the art for high-energy cylindrical lithium-ion batteries, while Tesla proposed the new 4680 format with a continuous "tabless" design as the choice for electric vehicle applications. Using an experimentally validated multidimensional multiphysics model describing a high energy NMC811/Si-C cylindrical lithium-ion battery, the effects of tabless design and cooling topologies are evaluated for 18650, 21700, and 4680 cell formats under varying charging protocols. Mantle cooling is found to be the most efficient cooling topology for a segmented tab design, whereas tab cooling performs equally well for tabless cells and achieves better performance for the 4680 format. By massively reducing polarization drops (approx. 250 mV at 3C) and heat generation inside the current collectors (up to 99%), the tabless design increases cell homogeneity and enables format-independent scalability of fast-charging performance with a tab-cooling topology. In addition, the 0 to 0.8 SoC charge time can be reduced by 4 to 10 minutes compared to cells with a segmented tab design, resulting in 16.2 minutes for the 18650 and 21700, and 16.5 minutes for the larger 4680 cell format.

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Lithium-and manganese-rich NCM (LMR-NCM) cathode active materials exhibit a pronounced energy inefficiency during charge and discharge that results in a strong heat generation during operation. The implications of such a heat generation are investigated for large-format lithium-ion batteries. Small laboratory cells are generally considered isothermal, but for larger cell formats this heat cannot be neglected. Therefore, the heat generation of LMR-NCM/graphite coin cells and NCA/graphite coin cells as a reference is measured for varying charge/discharge rates in an isothermal heat flow calorimeter and scaled to larger standardized cell formats. With the aid of thermal 3D models, the temperature evolution within these cell formats under different charge/ discharge operations and cooling conditions is analyzed. Without an additional heat sink and any active cooling of larger LMR-NCM/graphite cells, discharge C-rates lower than C/2 are advisable to keep the cell temperature below a critical threshold. If the loads are increased, the cooling strategy has to be adapted to the specific cell format, otherwise critical temperatures above 60°C are easily reached. For the investigated convective surface cooling and base plate cooling scenarios, thick prismatic cell formats with LMR-NCM are generally unfavorable, as the large amount of heat cannot be adequately dissipated.

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