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thermisch-elektrische Batterie-modellierung

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Presentation on theme: "thermisch-elektrische Batterie-modellierung"— Presentation transcript:

1 thermisch-elektrische Batterie-modellierung
W. Beckert, Christian Freytag, T. Frölich, M. Wolter

2 Fraunhofer Institut f. Keramische Technolog. u. Systeme Dresden
Arbeitsgruppe Modellierung und Simulation: Multiphysics-Feldsimulation (FEM, CFD); Reaktive Strömung; homogenisierter Ansatz für heterogene Mesostrukturen; (Systemsimulation) Thermisches Management von Energiesystemen, ... (SOFC-Stacks + Komponenten, thermoelektrische Generatoren, Li-Ion-Batterien,...) High-Temperature-Fuel-Cell-Systems Thermo-Electric-Generator Diesel-Particulate-Filter

3 Our Model Approach for Batteries

4 Homogenisation model for winding body
current collector porous cathode porous anode isolator separator/ electrolyte cell laminate anode side current distributor phase cathode side current distributor phase "el.-chem." active phase: transverse charge transfer simplified 3-phase homogenised continuum approach intrins. potential polar. resistance DOF: Uano Ucath T composite homogen. volume element combine into PDE: anode side charge balance/ potential PDE: cathode side charge balance/ potential Constitutive equ.: electric characteristics PDE: thermal balance transverse (electrolyte) current density

5 Model for local electrical characteristics
Constitutive equation for el.-chem. active phase: intrinsic electrochemical potential cell polarisation resistivity Empirical Approach: Shepherd's Model [1] [C. M. Shepherd "Theoretical design of primary and secondary cells. Part 3: battery discharge equation" NRL Report 5908; May 1963

6 Introduction into SHEPHERD-Model*
Discharge: Charge: * ref.: [1]

7 Introduction into SHEPHERD-Model
Discharge example from SHEPHERD-Paper (NiCd-cell):

8 Introduction into SHEPHERD-Model
Extensions and adaptions to original SHEPHERD-Model: for OCV* for linear range  only valid for isothermal and galvanostatic conditions * ref.: [2]

9 Introduction into SHEPHERD-Model
LFP C-Cell Thermal-dependence of SHEPHERD-parameters:

10 Introduction into SHEPHERD-Model
transient battery model [3, 4, 5]: extended SHEPHERD-Modell (i≠const) non-galvanostatic part galvanostatic part(i=const) open circuit voltage (equilibrium) transient term +

11 Models and Results (Batterie Cell Level)

12 Model Geometry: Example: cylindrical cell with contact tabs (LiFePo4 , ANR 26650) separated current collector tabs, embedded between windings nonhomogeneous contacting with current concentration toward cont. tabs helical current flow + current collection  3D-model approach

13 Hybrid 2D-3D Model with Thermal  Electric Coupling
Concept: Combined 2D electric  3D thermal model for winding body electric problem: 2D frame Uano(l,y), Ucath(l,y), jelek(l,y) Qdiss(l,y) (unrolled electric film composite) COMSOL: allows integrated mapping simultaneous cosimulation ( ) T k s = ( ) T U = y jelek(l,y) l Mapping Operation T information transfer Qdiss T(x,y,z) Map 3D  2D Temperature Map 2D  3D Dissipation Heat thermal problem: 3D frame T(x,y,z) (thermal composite) ( ) 4 3 2 1 & rev uc elec diss d eff th Q h j T U × - = Ñ å , σ λ

14 Hybrid-Model Results: 3D-thermal model branch
Transient analysis with current pulse pattern of hot spots, induced by contacting structure temperature 50.2 Dt= 6 s dynamic analysis current pulse: duration 6 s Imax = 95 A = 40 C reasonable magnitude for practical operation 47.8 (LiFePo4, 26650, Ri= 10 mW) high dynamic load + small area contacts  hot spot formation

15 Completion: 3D-Model with Housing
Geometry/ Mesh generation winding domain: Comsol-generated add housing + contact structure: CAD-Import connecting meshs by interface elements

16 3-D Model with Housing: Results
41.9°C 40°C Temperature [°C] 35°C succesfull analysis of full cell geometry computation time: 2-6 h comparable results (hot spot formation) to winding body analysis 30°C 25°C 20°C 21.9°C 41.9°C<T<29.0°C dynamic analysis I  130 A  54 C Dt = 6 s

17 Models and Results (System Level)

18 Implementation in SimulationX 3.5
Modelica 3.2

19 Implementation in SimulationX 3.5
7 3 4 6 5 2 1 transient term +

20 Application on External Data
Sources of used data: experimental data for LFP C-Cell: discharge 1C, 5C, 10C including temperature data data from COMSOL build-in battery-model [6]: pulse discharge: 1C, 5C no temperature data included  SHEPHERD-parameters via external data fit (Excel)

21 Application on External Data
Terminal voltage from a LFP C-Cell 1C 2,1A 5C 10,5A 10C 21A

22 Application on External Data
Temperature profile during discharge of a LFP C-Cell

23 Application on External Data
1C - pulse discharge for COMSOL-Model: peak 17,5A duty cycle 300s periode 2000s

24 Application on External Data
5C - pulse discharge for COMSOL-Model: peak 87,5A duty cycle 100s periode 2000s

25 Summary hybrid 2D-electric + 3D-thermal composite approach with
50.2 hybrid 2D-electric + 3D-thermal composite approach with geometrical details thermo-electric coupling homogenised 3 phase model for winding composite simple empirical model for electrical characteristics result: contact structure acts as source for thermal hot-spots in dynamic loads approach has potential for use in multi-cell models good, robust and simple model for description of terminal voltage resolution for isothermal and galvanostatic restriction of original model sufficiently accurate match between experiment and model 47.8

26 Outlook "Virtual Battery Thermal Lab"-Tool:
Prototype example: [IKTS] curved LTCC substrate thick-film resistor electrolyte tolerant resolution: +/- 0.6 K "Virtual Battery Thermal Lab"-Tool: analyse/ understand internal thermal processes „benchmark" for simpler models tool for cell design optimisation IKTS activity: internal cell temperature sensor assist design process optimise sensor positioning analyse effects from interference of sensor-cell implementation of charge behaviour data fit in SimulationX/Modelica coupled thermal-electric model

27 Wish List to Modelica … simple data import to Modelica
simple data fit function in Modelica (bidirectional) interface to FEM

28 References [1] C. M. Shepherd: Theoretical design of primary and secondary cells part III - battery discharge equation NRL Report 5908 Washington, D.C [2] O. Tremblay, L.-A. Dessaint, A. I. Dekkiche: A Generic Battery Model for the Dynamic Simulation of Hybrid Electric Vehicles Vehicle Power and Propulsion Conference 2007. [3] A. Jossen: Fundamentals of battery dynamics Journal of Power Sources 154 (2006) 2, S. 530–38. [4] N. Sekushin: Equivalent circuit of Warburg impedance Russian Journal of Electrochemistry 45 (2009), S. 828–32. [5] F. M. González-Longatt: Circuit Based Battery Models: A Review 2do congreso iberoamericano de estudiantes de ingenieria electrica, 2006. [6] COMSOL Multiphysics User’s Guide: Rechargeable Lithium-Ion Battery Version 3.5a, 2008.

29 This work was kindly funded by:
Acknowledgments Fraunhofer IKTS: Georg Fauser Adrian Goldberg Diana Leiva Pinzon IAV GmbH Chemnitz: Carolus Grünig Mirko Taubenreuther Daniel Tittel This work was kindly funded by: Europäische Fond für regionale Entwicklung (EFRE) and the Freistaat Sachsen

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