Cycle aging tests of high-capacity (Ah) Li-ion cells are cost and time intensive since (i) high currents have to be applied (expensive measurement set-up) and (ii) predicting the cell aging behavior requires many tests with different parameters, e.g. temperature, C-rate, depth of discharge. Analyzing the aging behavior of large Li-ion cells by means of cycling the extracted cell material in small coin cells would tremendously lead to a faster and effective aging prediction. Many aging tests could be parallelized since only very low currents are needed. The condition for comparability between coin- and original cells is the same aging mechanism in both cell types and a reproducible coin cell assembly.

We test our coin cell assembly method on 40 Ah Li-ion pouch cells. We extract 62 coin cells out of three pristine 40 Ah pouch cells. The coefficient of variation in capacity of those coin cells at begin of life is 1.42% which is in the range of cell-to-cell variations of industrially produced cells at begin of life. Calendar and cyclic aging tests of 40 Ah pouch cells and extracted coin cells are conducted at different temperatures. Differential analyzes and impedance measurements help to detect the aging mechanisms of both cell types.

Finally, factors are introduced which may explain the measured offset in the respective aging curves.