From Laboratory to Application – Differences between Small and Large Battery Cells

The development of batteries with new materials typically starts with small active material amounts and consequently with small cells, often with low-loaded electrodes. As development progresses to increasing technology readiness levels, mid-sized and large cells with thicker electrode coatings are mandatory. However, large cells have different electrochemical and physicochemical properties than small lab cells. Herein, we discuss similarities and especially differences in the behavior of small laboratory cells (e.g. coin) and larger cells (cylindrical, pouch, prismatic), regarding cell design, electrode thickness, specific energy on material and cell level, heating behavior due to current flow, impedance, voltage curves, and rate capability. Impedances at 1 kHz are reduced by three orders of magnitude from coin cells to large cells while heating power is increased by a factor of 10 2 to 10 5 . By comparing specific capacities on cathode material level with those on cell level for commercial cells, we find a reduction by a factor of ∼3 to ∼5, depending on the anode coating thickness. The large general gap from pure material to cell and between small laboratory, mid-sized, large pilot, and commercial cells need to be taken into account from the beginning of battery development to avoid potential misinterpretation.