Electrical and Structural Characterization of Large‐Format Lithium Iron Phosphate Cells Used in Home‐Storage Systems

• Published in: Energy technology (Weinheim, Germany) Germany), 2021-06, Vol.9 (6), p.n/a
• Main Authors: Yagci, Mehmet C., Behmann, René, Daubert, Viktor, Braun, Jonas A., Velten, Dirk, Bessler, Wolfgang G.
• Format: Article
• Language: English
• Subjects: Chemical analysis; Chemical properties; Electrical properties; Electrode materials; Electrodes; Energy storage; Format; Iron; Iron phosphates; large format; Light microscopy; Lithium; lithium iron phosphate; Lithium-ion batteries; Microscopy; Microstructural analysis; Optical microscopy; Performance assessment; performance characteristics; Performance prediction; Storage systems; Structural analysis; Weight analysis
• ISSN: 2194-4288; 2194-4296
• DOI: 10.1002/ente.202000911

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. Stationary storage systems require large‐format lithium‐ion battery cells. This article presents a study of electrical, thermal, chemical, and structural properties of 180 Ah lithium iron phosphate/graphite cells. Charge–discharge experiments reveal the energy content and cycling efficiency. Light and electron microscopy reveals details of the electrode morphology. The results allow to derive parameter sets for modeling and simulation.