Electrical and Structural Characterization of Large‐Format Lithium Iron Phosphate Cells Used in Home‐Storage Systems
Mehmet C. Yagci, René Behmann, Viktor Daubert, Jonas A. Braun, Dirk Velten, Wolfgang G. Bessler
Abstract
This article presents a comparative experimental study of the electrical, structural, and chemical properties of large‐format, 180 Ah prismatic lithium iron phosphate (LFP)/graphite lithium‐ion battery cells from two different manufacturers. These cells are particularly used in the field of stationary energy storage such as home‐storage systems. The investigations include 1) cell‐to‐cell performance assessment, for which a total of 28 cells are tested from each manufacturer; 2) electrical charge/discharge characteristics at different currents and ambient temperatures; 3) internal cell geometries, components, and weight analysis after cell opening; 4) microstructural analysis of the electrodes via light microscopy and scanning electron microscopy; 5) chemical analysis of the electrode materials using energy‐dispersive X‐ray spectroscopy; and 6) mathematical analysis of the electrode balances. The combined results give a detailed and comparative insight into the cell characteristics, providing the essential information needed for system integration. The study also provides complete and self‐consistent parameter sets for the use in cell models needed for performance prediction or state diagnosis.