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© Fraunhofer THERMISCH-ELEKTRISCHE BATTERIE- MODELLIERUNG W. Beckert, Christian Freytag, T. Frölich, M. Wolter.

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Presentation on theme: "© Fraunhofer THERMISCH-ELEKTRISCHE BATTERIE- MODELLIERUNG W. Beckert, Christian Freytag, T. Frölich, M. Wolter."— Presentation transcript:

1 © Fraunhofer THERMISCH-ELEKTRISCHE BATTERIE- MODELLIERUNG W. Beckert, Christian Freytag, T. Frölich, M. Wolter

2 © Fraunhofer 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,...) H igh -T emperature -F uel -C ell -SystemsT hermo -E lectric -G enerator D iesel -P articulate -F ilter

3 © Fraunhofer 3 Our Model Approach for Batteries

4 © Fraunhofer 4 Homogenisation model for winding body PDE: anode side charge balance/ potential PDE: cathode side charge balance/ potential Constitutive equ.: electric characteristics winding PDE: thermal balance current collector porous cathode porous anode isolator separator/ electrolyte current collector 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: U ano U cath T composite homogen. composite volume element combine into transverse (electrolyte) current density

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

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

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

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

9 © Fraunhofer 9 Thermal-dependence of SHEPHERD-parameters: LFP-6745135-30C-Cell Introduction into SHEPHERD-Model

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

11 © Fraunhofer 11 Models and Results (Batterie Cell Level)

12 © Fraunhofer 12 Model Geometry: Example: cylindrical cell with contact tabs ( LiFePo 4, 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 © Fraunhofer 13 Hybrid 2D-3D Model with Thermal  Electric Coupling Concept: Combined 2D electric  3D thermal model for winding body electric problem: 2D frame U ano (l,y), U cath (l,y), j elek (l,y)  Q diss (l,y) thermal problem: 3D frame T(x,y,z) Map 3D  2D Temperature Map 2D  3D Dissipation Heat l y T(x,y,z) j elek (l,y) T Q diss COMSOL: allows integrated mapping + simultaneous cosimulation (unrolled electric film composite) (thermal composite) information transfer       rev uc elec diss d dddeffth Q h j T U T Q QT      0, )( jjσλ  T kk   TUU 00 

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

15 © Fraunhofer 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 © Fraunhofer 16 3-D Model with Housing: Results Temperature [°C] 41.9°C 21.9°C 41.9°C { "@context": "", "@type": "ImageObject", "contentUrl": "", "name": "© Fraunhofer 16 3-D Model with Housing: Results Temperature [°C] 41.9°C 21.9°C 41.9°C

17 © Fraunhofer 17 Models and Results (System Level)

18 © Fraunhofer 18 Implementation in SimulationX 3.5 SimulationX 3.5 Modelica 3.2

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

20 © Fraunhofer 20 Application on External Data Sources of used data: experimental data for LFP-6745135-30C-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 © Fraunhofer 21 Application on External Data Terminal voltage from a LFP-6745135-30C-Cell 1C2,1A 5C10,5A 10C21A

22 © Fraunhofer 22 Application on External Data Temperature profile during discharge of a LFP-6745135-30C-Cell

23 © Fraunhofer 23 Application on External Data 1C - pulse discharge for COMSOL-Model: peak17,5A duty cycle300s periode2000s

24 © Fraunhofer 24 Application on External Data 5C - pulse discharge for COMSOL-Model: peak87,5A duty cycle100s periode2000s

25 © Fraunhofer 25 Summary 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 50.2 47.8

26 © Fraunhofer 26 Outlook "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 Prototype example: [IKTS] curved LTCC substrate thick-film resistor electrolyte tolerant resolution: +/- 0.6 K

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

28 © Fraunhofer 28 References [1]C. M. Shepherd: Theoretical design of primary and secondary cells part III - battery discharge equation NRL Report 5908 Washington, D.C. 1963. [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 © Fraunhofer 29 Fraunhofer IKTS:Georg Fauser Adrian Goldberg Diana Leiva Pinzon IAV GmbH Chemnitz: Carolus Grünig Mirko Taubenreuther Daniel Tittel Acknowledgments This work was kindly funded by: Europäische Fond für regionale Entwicklung (EFRE) and the Freistaat Sachsen

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