Seifert, H.J.

Ziebert, C.

English

Seifert, H. J.

KITopen

KIT – University of the State of Baden-Wuerttemberg andNational Research Center of the Helmholtz AssociationElectrochemical-calorimetric studies on safety fundamentals of cylindrical lithium ion cells2nd Int. Conference on Materials for Energy EnMat IIMay 12‐16, 2013, KarlsruheCarlos Ziebert, Hans J. Seifert, Karlsruhe Institute of Technology, Institute for Applied Materials –Applied Materials Physics (IAM-AWP), Karlsruhe, GermanyOne of the most urgent tasks for the extensive introduction of stationary storagetechnologies and electric mobility is to provide safe and reliable lithium-ion cells.Insufficient heat transfer to the environment during charging and discharging can lead toa loss of battery power but also to uncontrolled reactions (thermal runaway) and ignitionto cause an explosion. In this study, commercial cylindrical lithium ion cells were testedunder isoperibolic and adiabatic conditions in an accelerating rate calorimeter (ES-ARC)to investigate their performance and thermal behavior. By measuring the overall heatcapacity of the cell and the calorimeter constant heat data were determined, which canbe used as input for thermal modeling and for a thermal management system.Boeing Dreamliner: wrongmaterials choice(courtesy Reuters)(courtesywww.cbsnews.com)Laptop: internal shortcircuitIsoperibolic cycling of cylindrical cells 1C rate, 30 °CAccelerating Rate Calorimeter (ARC)Heat generation rateIdeal conditions (single cell)Real conditions (battery pack)We gratefully acknowledge the financial support by the priority programme SPP 1473 WeNDeLIB of theGerman Science Foundation (DFG) and by the Portfolio Initiative of the Helmholtz AssociationHeat dissipationCp measurements• Significant temperature rise even for low charge/ discharge rates especially for adiabatic conditions• Heat data were determined, which can be used as input data for thermal modeling• Next steps: - Assignment of heat effects to electro-chemical processes and components     - Separation of reversible and irrever-sible heat effects  TUITUUIQcellOCPcellcellOCPI CurrentcellOCPUHeat generation rate(evolved or absorbed)QcellUCell equilibrium or open circuitpotential Cell operating potential TU cellOCPcellOCPUEntropic coefficientand  are SOC dependentIrreversible heat generation: Ohmic losses and reactionresistancesReversible entropic heatgenerationTop sensorBomb sensorSide sensorBottom sensorES-ARC, Thermal Hazard TechnolgyManufacturer: A123Cell type: APR18650M1Cathode material: LiFePO4 (LFP)Nominal capacity: 1100 mAhNominal voltage: 3.3 VVoltage window: 3.6 V to 2 VCore cell weight:  39 gHitachi MaxellINR18650PB2LiMn2O4 (LMO)1400 mAh3.7 V4.2 V to 2.5 V41 gCell specifications0 200 400 600 800 1000 12003032342.42.62.83.03.23.43.63.84.04.2-2-1012 Temperature [°C]Time [min] Voltage [V]  Current [A]0 200 400 600 800 1000 12003032342.22.42.62.83.03.23.43.6-2-1012 Temperature [°C]Time [min] Voltage [V]  Current [A]APR18650M1 INR18650PB20 200 400 600 800 1000 120030405060702.22.42.62.83.03.23.43.6-2-1012 Temperature [°C]Time [min] Voltage [V]  Current [A]0 200 400 600 800 1000 1200 1400 16002030405060702.42.62.83.03.23.43.63.84.04.2-2-1012 Temperature [°C]Time [min] Voltage [V]  Current [A]U = 3.3VCalorimeter constant determination1.03468	– 0.00718372  0.00013056 ∙e.g.  at 30 °C  cp 	0.94	J/g	K∙ 	∆APR18650M10 100 200 300 400 500 600203040506070  Temperature [°C]Time [min] Tenv Tdummy cell: cylinder of AlMgSi0.5 EN AW‐6060 F22 with same dimensions as 18650 cellsARC 	(0.04  0.001) W/K0 200 400 600 800 10000501001502002501C0.5C0.25C   Heat dissipation rate [mW]Time [min]APR18650M130 °Cq d = ARC TConclusions/Outlook0 1000 2000 3000 4000-3-2-10123  ln(Tenv-T)Time [s]Adiabatic cycling of cylindrical cells, 0.5 C rateAPR18650M1 INR18650PB2Contact: Dr. Carlos Ziebert, Phone: +49 721 608-22919; E-Mail: carlos.ziebert@kit.edu

Electrochemical-calorimetric studies on safety fundamentals of cylindrical lithium ion cells

https://publikationen.bibliothek.kit.edu/220094441/3816452

Electrochemical-calorimetric studies on safety fundamentals of cylindrical lithium ion cells

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