Within the FoFeBat2 project, two large-format prismatic lithium-ion cells (86 Ah, NMC622) were developed, assembled, and systematically finished and tested to validate mechanical design features. The cells were manually assembled without dry room conditions. The goal was to specifically investigate mechanical influences on cell performance. The finishing process included vacuum drying, electrolyte filling under nitrogen, mechanical fixation, and electrochemical formation. During formation, approximately 12% of input energy was consumed for SEI formation, with total energy efficiency reaching 99.2% after three cycles. The target capacity of 86 Ah was achieved with less than 1% deviation. To evaluate the mechanical design’s impact on cell resistance, serial resistance (R₀) via electrochemical impedance spectroscopy (EIS) and direct current internal resistance (DCIR) were measured and benchmarked against Tesla 4680 and BYD Blade reference cells. The prototype cells exhibited relative (R₀/DCIR) resistance values within the range of commercial cells, though a ~10% variation between prototypes highlighted sensitivities of manual assembly. The study demonstrates that prototype cells with novel mechanical designs can achieve industrially relevant resistance and performance metrics but emphasizes the need for automated processes to ensure reproducibility. The established benchmarks provide valuable input for future pilot-line and industrial cell developments.