Electromobility with fuel cells

Transcription

1 Electromobility with fuel cells Kriston Ákos, Eötvös Loránd University Dr. Karl Dobos, FuelCell Innovations

2 Agenda The future of Electromobility About us The basic energetics of electrochemical devices Fuel cells in general Electrochemistry of fuel cells Technological challenges

3 What is electromobilty? When virtual reality become real

4 Mobile (fast), democratic, sustainable

5 Fuel cell research in Hungary and in Dortmund Harmonization of electrochemistry and mathematical simulation Basic electrochemical research Simulation framewokrs Applied electrochemistry Fuel cells (PEM, DMFC) Sensors Membran microreactors

6 III. Alternative driven vehicle race, 008. EPR08 WireCar Small DMFC unit PEM battery charger

7 IV. Alternative driven vehicle race, HY-GO 009.

8 Hy-Go.0, V. Alternative Driven Vehicel s race, 010. Prototype vehicle for car-sharing

9 Electrochmical energy conversion devices

10 Batteries and capacitors Capacitor, Supercapacitor 1 E= LaCVf V0+ 4 ( ( IR) ) Battery E= G= nfvc = H T S Chem. Rev, 104, 445 (004)

11 Fuel cells CO, H O N, H O, O

12 Comparison of energy conversions η ta. cell Chemical energy Electric energy 100 Reversible theoretical efficiency η ta.cell =- G r / H r 80 η=100 % Efficiency, % Reaction heat Carnot efficiency η =( T f -T a )/T f η~100 % Heat η heat Temperature, o C, ( T ta. cell ill. T f Carnot ) Mechanical energy

13 Theoretical energy densities

14 Tank-to-wheel analysis (Shell)

15 Well-to-whell analysis Oil consumption CO emission

16 Comparision of BEV and FC technology

17 Comparison of charging times Vehicle Range (miles) Energy Required from Grid (kwh) Level 1 Charging Time (hours) Battery Electric Vehicles Level Charging Time (hours) Level 3 Charging Time (hours) Level 3 Charging Time (hours Fuel Cell EVs Hydrogen Tank Filling Time (hours) 10V, 0A 40 V, 40A 480V, 3Φ 480V, 3Φ 1.9 kw 7.68 kw 60 kw 150 kw

18 State-of-the-art

19 Grove History Older then an ICE engine Az Nicholson elektrolízis and Carlise, elvének invention felfedezése of Nicholson electrolysis és Carlise Az Sir FC William elvének Grove, felfedezése invention cells Sir William Groove Az első víz elektrolízis Az FC alkalmazása az űrben the Apollo and Gemini Apollo és Gemini program Szilárd PEM electrolyser polimer elektrolit víz elektrolízisre FC (Ballard) alkalmazás gk.-ban invention of fuel Ostwald and Nernst, foundation of electrochemistry and fuel cells Az FC elmélete Ostwald és Nerst The first industrial electrolyser The application of the first alkali FC in Gemini program (Sir Francis Bacon) Application of PEM in vehicles The reduction of Pt by 90 % A Pt-koltség jelentős csökkenése Advanced systems Jelentős fejlődés Transition to. economy Átmenet a hidrogén alapú gazdaságba 1839

20 Application ranges Portable electronic devices Higher energy density fast charging Vehicles, households, boats Zero emission, higher efficiency Power industry Zero emission Higher efficiency Noiseless operation W 1k 10k 100kW 1M 10MW Methanol Alkali Carbonate Proton exchange membrane Phosphoric acid Solid oxide James Larminie: Fuel cell systems, explained, 004, Willey

21 Types of fuel cells Type Electrolyte Temperature Electrochemical reaction Proton exchange membrane (PEM) Solid conducting polymer, Naffion H 1 O H + e + + e + H + H O Alkaline FC (AFC) KOH solution H 1 O + (OH ) H O+ e + H O+ e + H + (OH ) Phosphoric Acid FC (PAFC) Molten carbonate FC Phosphoric Acid Molten Li-, Na-, K carbonate H 1 O H 1 O H + e + CO CO + e + H H + + e H + H O O+ CO + + e CO 3 Solid oxide Solid zirconium oxide H + O 1 O + e H + H O+ e + O

22 Typical applications Type Application Advantage Drawback PEM Mobile application, transportation Immediaty startstop, highest power density Expensive, sensitive to the fuel and the air contaminants AFC Military, Space Efficient, faster oxygen reduction Sensitive to the CO PAFC MCFC Stationary power generation Stationary power generation 85 % efficiency Insensitive to the fuel type High cogenerative efficiency, low emission Low current and power, Pt catalyst Corrsion of the electrode, long start-up SOFC Housholds, military Cogeneration the oxide is sensitive to the temperature fluctuations

23 The well known fuel cell

24 The first industrial FC, Apollo unit

25 Molten carbonate FC(MCFC) MTU Friedrickshafen 30 kw electric energy 10 kw heat Natural gas, biogas 600 o C temperature

26 Othr interesting applications

27 Auxiliary power units Fort Jackson, SC, USA Diesel generator Fuel cell back-up solution

28 Trasnportation applications

29 Complex systems

30 FC vehicles in Columbia, SC

31 Hydrogen filling stations

32 University projects

33 Proton exchange membrane fuel cells

34 The heart of the fuel cell (MEA) anode cathode H, ta. O, air szén szemcsék gáztranszport vízzel telített mikropórusok mezopórusok Pt- nanorészecskék flow field gas-diffusion layer ~50 µm µm catalyst ~5µm polimer membrane 5-00 µm

35 Characterization of fuel cells (PEM)

36 Operating conditions - efficiency 1. T=80 o C, fully humidified. T=80 o C, 50% humidified 3. T=80 o C, dry gas

37 The electrochemical behaviour H 1 O H + e + + e + H + H O

38 Basic equations j = nfv O + n e k red R n k ox v red = k red c O (0, t) = j c /nf v ox = k ox c R (0, t) = j a /nf j = currents density, v = reaction rate Schema of an electrochemical reaction j c = cathodic current j a = anodic current v = v red v ox = k red c O (x = 0) k ox c R (x = 0) = j/nf k = χzexp ( G /RT) G = free energy of the activation of the reaction ( G α / n i ) P,T = β αφ = Φ β Φ α µ% i α = µ α i + z i FΦ α µ% µ i α i α potential = electrochemical potential, = chemical Φ α = the electric potential of theαphase

39 The dynamic equations η = E E e j = j o η = overpotential, E e = equilibrium potential of the reaction co ( x= 0) cr ( x= 0) exp( α * cnfη) + exp( α * anfη) co c R j = j o [ exp ( α c nfη) + exp(α a nfη)] Erdey-Grúz Volmer equation η= a + b lg j Tafel equation R ct = RT /nfj o R ct = charge transfer resistance

40 Electrochemistry in atomic scale

41 Governing equations of a FC

42 The behaviour of porous electrodes potential / V Cella feszültség / V Cell potential 0,9 0,8 0,7 0,6 0,5 0,4 Kinetic migration Proton migration, diffusion σ c c Ai0 L 0 c D σ eff eff KAi c eff c cai 0 c Ai αf K exp u RT αf Lcexp u RT K αf exp u RT D eff αf K exp u 4RT 0,3 0,01 0,1 1 Current Áram sûrûség density / Acm - / Acm -

43 Simplified systems The basic processes i i 1 σ ϕ x 1 = eff ϕ = κeff x i1 i = x x Ohm s low in the solid Ohm s law in the electrolyte Electroneutrality + charge transfer between the two phases

44 The canonic form WhereXés tau the nondimensional form of space and time ( ) ), ( ), ( ), ( τ ν τ τ τ X u f X x u X u = Diffusion part Source term

45 Nonuniform reaction profile 1,0 0,8 0,6 0,4 I=0,01 Acm - I=0,1 Acm - I=0,5 Acm - Dimenziómentes reakció sebesség 1, 0,8 0, Cell Voltage / V Dimensionless reaction rate 0,4 0,0 0,0 0,3 0,6-0,0005 0,0000 0,0005 0,0010 0,0015 0,000 0,005 0,0030 0,0035 Current density / Acm - Length / cm Katód keresztmetszete / cm

46 PEMFC for transportation

47 Problems of electrochemical devices Power density / W kg -1 Energy density / Wh kg -1 Chem. Rev, 104, 445 (004) 47

48 Hybrid powertrains 48

49 FC-SC hybrid systems 49

50 F-Cell systems 50

51 Optimization of the system Required power / W FC Power / W Battery power / W Power / W time / sec

52 Effect of pressure for the MEA s performance 1,0 0,9 bar 1 bar 0,4 Cell Voltage / V 0,8 0,7 0,6 0,5 0,4 0,3 0, 0,1 Power / Wcm - 0,3 0, 0,0 0,0 0,3 0,6 0,9 1, Current density / Acm -

53 Effect of the pressure at the system level ,95 1 bar bar 880 Hydrogen level / l 4,9 4,85 4, Battery charging level / Ah 4, ,

54 Design

55 Brushless Motor System Advantages of Intermotor BLDC (permanent magnet DC) motor technology: efficiency is more than 90% no friction, silent running no need of maintenance, high endurance has consistent torque, so can be used in wide range of rev smaller BLDC motor can produce more power optimised for direct drive with minimised mechnical losses

56 Control of the FC systems

57 Hydrogen storage in practice metal-hydride or high pressure canister? Advantages: Higher range Small pressure Easier to recharge Drawbacks Hydrogen desorption is slow Temperature control is needed Recharging takes 3 hours Sensitive to impurities 900 liter Hydrogen theoretically 600 W discharge 0 bar % Hydrogen is used

58 Safety

59 Operation strategy Electric network Electrolyzer Selling the heat Hydrogen fuel Selling the oxygen HY-GO vehicle Fare Spaces for advertisements Extra services

60 Optimization of the car-sharing system RoR / Months Price of the vehicle $5 000,00 $6 50,00 $7 500,00 $8 750,00 $10 000,00 $11 50,00 10% 0% 30% 40% 50% 60% 70% 80% 90% 100% Utilization

61 Acknowledgement Dr. Karl Dobos Dr. Inzelt György and Dr. Faragó István Kriston Ákos Coordination Molnár Norbert Electric engineer Szabó Tamás - Pilot, mathematician Fülöp Zoltán Control Berkes Balázs electrochemist Vesztergom Soma data acquisition Gyepes Tamás - sponsor

62 Next steps Application of Neutron radiography to detect water accumulation in the flow fields Refining the technique to detect water in the porous media Cyclic operation between SC and FC Detection of microstructural changes Cooperation with Solar Club

63 Sponsors

64 Thank you for your attention! Contact: Kriston Ákos,