Electro-Thermal Analysis of Lithium Ion Batteries: Experimental and Numerical study Gad A. Pinhasi The Israeli Fuel Cell and Batteries Center (IFCBC) Conference 26 January 2011, Tel Aviv University 1
Outline • The Objective • The Project • Background – Internal Resistance – Heat Generation • The Study • Experimental Setup – Calorimeter • Models – Lumped heat model – CFC model • Results – Cell – Battery – Pack 4 • Conclusions • Summery 2
The Objective • Thermal Analysis and Design of a Large Battery Pack. • To evaluate the heat generation and temperature field under various electrical loads and design specifications. – Safety: Thermal Runaway – Max. Temperature restriction: – “Passive cooling” solutions 3
The Project • Evaluation of Heat Generation: – Source term – Experimentally • Calculation of the Temperature Field – Numerically • Cell, Battery, Packs : 4, 92 4
Cell, Battery and Packs Cell Pack 4 ICR 18650 Samsung MR-2791 YT-600 24 cells 4 bat 91(+1) bat 4 S× 6 P Type Battery 4 P 7 S× 13 P Voltage: [V] 3. 7 16. 8 Capacity: [Ahr] 2. 6 14. 4 57. 6 Discharge currents [A] 0. 2, 0. 4, 1 3, 4, 8 Pack 92 32 5
Introduction • Evaluation of Heat Generation – Experimentally • Calculation of the temperature field – Numerically • Model Approaches • Thermal characterization • Battery Internal 6
Model Approaches • Fundamental models • physical foundations principles – Transport Phenomena • Phenomenological models • Equivalent circuit models 7
Thermal characterization • The heat produced due to: • Joule heat of the electrical resistance • Polarization heat • Reaction heat – initially exothermic during discharge – reversible 8
Battery Internal Resistance • The cell voltage under load is : – Open circuit voltage – Internal Ohmic resistance – “Concentration polarization” – “Charge transfer polarization” • Methods for Determining the Internal Resistance – – Ohm’s Law Joule’s Law AC Resistance Electrochemical Impedance Spectroscopy (EIS) 9
Internal Resistance Dependence • Temperature – Decreasing with Temperature • State of Charge (So. C) • State of Health (So. H) (Yurkovich et al. (2009 10
Internal Resistance and Heat Generation • Joule heat of the electrical resistance • Open circuit voltage 11
The Study: Experimental and Numerical 12
Experimental Setup Dewar: Calorimeter FLUKE: Data Acquisition Liquid Bath Cell/ Battery/ Pack Charge/ Load Charge Load Silicone Fluid Dow Corning DC‑ 200/100 c. St Temperature Data logger 13
: Calorimeter • Batch / Continuous Flow (SHC) Calorimeter Tw, in Tw, out Toil, in 14
Numerical Study: Tools • Computational Fluid Dynamics (CFD) • Partial differential equations (PDEs) solvers: – Fluid Mechanics – Heat Transfer – Mass Transfer • (Diffusion) • Chemical reactions • COMSOL Multiphysics – Batteries & Fuel Cells Module • ANSYS – CFX – FLUENT 15
The Lumped Model • Cells • Battery Medium • Pack Medium • Heat Transfer Mechanisms T T 3 T 2 T 1 Cell q U 3 q”’ 24 U 23 U 12 ” Battery ’ 91 16
Results • Cell – Temperature history – Heat Generation and SOC • Battery • The Pack • Electrical resistance – Open-circuit voltage – Heat Generation 17
Samsung 18650 • ICR 18650 -26 C 2600 m Li-ion 3. 7 v Battery • Brand : Samsung • Nominal voltage : 3. 7 V • Capacity: 2. 6 Ahr • Size 18 mm x 65. 0 mm • Weight : 48 g/pcs • Made in JAPAN 18
Cell Heat Generation and SOC 2. 6 A 1 A 19
Pack 4 • YT-600 • 4 Batteries 2791 • 4 P • Voltage: 16. 8 Volts • Capacity : 57. 6 Ahr 20
Pack 4 • Current: 32 A • Temperature zeros – Battery inside – Battery Gap – Surrounding water • Electrical voltage • Electrical Power • Heat Power 21
Pack 4: Simulation • Experiment vs. Simulation • Medium Effect: – air/oil 22
Experiment vs. Simulation Experiment Simulation Points: Battery inside Battery Gap 0. 6 W/cell 23
Experiment vs. Simple model Points: Battery inside Battery Gap 0. 6 W/cell 24
Pack 4: Medium Effect : 32 A 100 min Tmax : 51ºC Oil • Tmax : 96ºC Air • 25
Summary • The heat generation and temperature field for battery packs were evaluated theoretically and experimentally • Internal resistance of a cell was determined by current step methods and thermal loss methods. • Future Work: – Heat generation Correlation – Dynamic models – Fundamental models 26
People • Dr. Gad Pinhasi – Department of Chemical Engineering and Biotechnology • Dr. Alon Kuperman – Department of Electrical Engineering • Neria Roth – (M. Sc. Student) Experimental Study • Itshak Shtainbach – (M. Sc. Student) Numerical Study 27
Acknowledgment The research is supported by the ISRAEL Ministry of Defense : MAFAT
29
30
Conferences Roth, N. , Shtainbach, T. , Kuperman, A. and Pinhasi, G. A. , "Electro-thermal Analysis of Lithium Ion Batteries: Experimental and Numerical study”, 1. The 31 st Israeli Conference on Mechanical Engineering - ICME 2010 , Dan Panorama Hotel, Tel. Aviv 2 -3 June 2010. 2. The 47 th annual meeting of the IICh. E, 2010. The Israeli Fuel Cell and Batteries Center (IFCBC) Conference, 2011 31
32
Скачать презентацию Electro-Thermal Analysis of Lithium Ion Batteries Experimental and
59432be19b76283cbae1359d81c4e363.ppt