An Overview of Battery Simulation Robert Spotnitz, Battery Design - PowerPoint PPT Presentation

An Overview of Battery Simulation Robert Spotnitz, Battery Design LLC

Overview A. Battery History B. Battery Market and Technology C. Battery Modeling 2

What is a battery? • A battery or “galvanic cell” converts chemical energy to electrochemical energy using at least one of reactant stored in a cell . • A fuel cell converts chemical energy to electrochemical energy using reactants stored externally. • A capacitor stores and releases electrical energy using double-layer charge separation or a pseudo-capacitive effect such as surface adsorption, reaction or bulk intercalation. Volta’s pile Ag/Zn (1800) 3

Terminology e -  e -  Battery consists of one or more cells Cell consists of a pair of electrodes and an ion conductor Ag 2 O  2Ag Electrode consists of active Zn  ZnO material, current collector, and OH - e -   e - tab Positive electrode is called “cathode” Negative electrode is called ionic “anode” conductor Package, separator, insulators,       etc. Zn 2 OH ZnO H O 2 e 2       Ag O H O 2 e 2 Ag 2 OH 2 2    Ag O Zn 2 Ag ZnO 4 2

1991: Li Ion 1959: Alkaline 1980s: NiMH 1958: Organic Li primary 1947: O 2 1994: Doyle, Fuller, Recomb. Newman, DUAL Ni/Cd model Li Ion 2005: Garcia et al., 1962: Newman and Tobias, microstructural 1866: Dry cell Porous Electrode Theory model 1860: Pb Acid 1800: Volta invents battery 1930: Butler-Volmer Eqn 1905: Nernst Equation:  G=-nFE               1887: Peukert’s Law: I p  t d =constant a c i i exp exp     o       RT RT 5 1834: Faraday’s law of electrolysis

Battery Market Only a few chemistries dominate market Rechargeable - Pb Acid - Lithium Ion Primary or single discharge - Alkaline

North American Lead Acid SLI Battery Forecast @ $60/battery ~$8 Billions 7

Worldwide Rechargeable Battery Sales Excluding Lead Acid by application Lithium Ion NiMH NiCd Lithium-ion dominates market for portable electronics. C. Pillot, Batteries 2009, Avicenne 8

Li-Ion Cell World Market Size & Forecast ($Billions) 35 Consumer Other 30 25 Industrial Automotive 20 15 10 5 Huge growth in conversion used $1 = 100 Yen lithium-ion market Consumer - phones, computers, cameras, etc. Other - power tools, e-bikes, medical, aerospace is forecast for Industrial - smart-grid, residential, UPS vehicles Automotive - passenger vehicles excluding bus, railroad 9 S. Inagaki, Yano Research Institute, SAE Intl. Vehicle Battery Summit, Shangahi 2011

Battery Requirements: Consumer Products • Consumer • Trends electronics – longer calendar life – high volumetric energy density – higher energy – low cost density – 1 year life – Safety • Power tools – high power density – low cost Largest market and – 2-3 year life growing. – safety 10

Battery Requirements: Hybrid Electric Vehicles Typical is ~1 kWh systems • High Power (> 1 capable of providing ~25 kW kW/kg) • Low cost • 8+ year life • Abuse tolerance Nickel metal hydride batteries dominate but lithium-ion is projected to win out by providing smaller, lower cost packs 11

Battery Requirements: Battery Electric Vehicles • High gravimetric Typical is 24 kWh systems capable of providing ~50 kW energy density (>100 Wh/kg) • Very low cost • 8+ year life • Abuse tolerance Lithium-ion is currently only viable chemistry with sufficient energy density for this application. 12

Battery Requirements: Grid Regulation • High power, fast response (seconds) • Cost? Life? Abuse? Market is potentially larger than automotive, but large uncertainty as to economic feasibility. 13

Lead Acid (Valve Regulated) - Actives and Separator Positive 2   cm 5 Negative a 2.3 10 2   cm 3 4 a 2.3 10 cm 3 cm   ~ 2 mm thick 40% ~ 2 mm thick   45% Charged PbO2 + 2e +2H + + 2H2SO4 Pb + H2SO4  PbSO4 + 2e + 2H +  PbSO4 + 2H2O Discharged Sep ~95% porous, ~1.3 mm thick D. Pavlov, V. Iliev, J. Power Src / 7 (1981) 153. J. H. Yan et al. , J. Power Src. 133 (2004) Lead-acid electrochemistry is very complex. 135-140.

Li-ion Cell Cross-Section Li + + e + Mn2O4  LiMn2O4 LiC 6  Li + + e + C 6 Z. G. Li et al. J. Electrochem. Soc. , 150 (9) A1171 (2003) Lithium ion battery operation is relatively simple. 15

Typical Lead-Acid Battery DOE-HDBK-1084-95 September 1995 16

Spirally-Wound Cells 17

Tesla Powertrain Technology Small Cells 18650 K. Kelty, 26 th Intl. Battery Sem., Ft. Lauderdale, Fl, 2009 18

Mitsubishi iMiEV Battery 22 modules (4 cells/module) 19

Summary • 2011 World Markets for Batteries – Primary • estimated at ~$4 Billions for alkaline and ~$1.5 billions for others – Rechargeable • lead acid ~$20 Billions • lithium ion ~$12 Billions • nickel metal hydride ~$1.5 Billions • Automotive market is growing rapidly and is amenable to design • Opportunities for – design tools for batteries – prediction of life and abuse tolerance 20

Overview A. Battery History B. Battery Market C. Battery Modeling 21

Battery Modeling • Concept of Electroactive Species • Concept of Exchange Current Density • Battery Equations and Modeling Approaches 22

 1  +  2 c           3 o Fe F G RT ln 1 2 c  2 Fe Nernst Equation Can compute voltage based on chemistry. 23

 1  +  2 c           3 o Fe F G RT ln 1 2 c  2 Fe Nernst Equation Can compute voltage based on chemistry. 24

 +      1 3 2 Fe e Fe            c 1 2 i k c exp    f f , o 3   Fe RT      2 3 Fe Fe e 2          a 1 2 i k c exp    2 b b , o   Fe RT   i i i net f b Butler-Volmer Equation Can compute reaction rates. 25

 +      1 3 2 Fe e Fe            c 1 2 i k c exp    f f , o 3   Fe RT      2 3 Fe Fe e 2          a 1 2 i k c exp    , 2 b b o   Fe RT   i i i net f b Butler-Volmer Equation Can compute reaction rates. 26

Lead Acid Battery   1 , Pb 1 PbO , 2   2 2     PbO 2 H SO Pb 2 PbSO 2 H O 27 2 2 4 4 2

    Pb 2 H SO PbO 2 PbSO 2 H O 2 4 2 4 2   1 , Pb 1 PbO , 2   2 2 28

  1 , Pb 1 PbO , 2  T        c p k T S Eulerian strain        t 1 T       * E I X X    x x RT 2         o  i 1 2 t ln a 2  2 2  F c       D c 2  i 2  t Ohm ' s Law               i i 1 v  1 1 t       Poisson 2 PbO 2 H SO 2 e PbSO 2 H O SO 2 2 4 4 2 4                       2   2 a 1 2 c 1 2 j k exp k c exp j      j PbO , a   PbO , c H SO   RT RT 2 2 2 4 1 j      2 Pb SO PbSO 2 e 4 4                    a 1 2 c 1 2 j k c exp k exp      , 2 , Pb a   Pb a   SO RT RT 4 29

Macro-Homogeneous Modeling Phenomena included in macro- J. Newman, C. Tobias, “Theoretical Analysis of homogeneous battery models Current Distribution in Porous Electrodes,” J. Echem. (partial) Soc ., 109,1183 (1962) L Separator • multi-component electrolytes • precipitation • side reactions Negative Positive • particle size distribution Electrode Electrode • mixtures of active materials • expansion/contraction of particles • convection • current distribution along r collectors • local heat generation • stress generation r  2 2 L 30

Hierarchy of Battery Simulation STAR-CCM+ Vehicle Module/Pack C BD Full Cell Unit Cell Hierarchy enables higher level models to be built on lower level models. 31