It s Not Easy Being Green Fuel Cell Vehicles. Dream or Reality?

Transcription

1 It s Not Easy Being Green Dr. Billy Wu billy.wu06@imperial.ac.uk Lecturer in the School of Design Engineering Head of Division for Autonomous Systems and Manufacturing Imperial College London Electrochemical Science and Engineering Group Date: 25/02/2015 1

2 Overview Technology road map Social acceptance Would you buy a fuel cell car? Cost How much is my fuel cell car? Infrastructure Where can I get hydrogen from? Performance and Durability How fast will my fuel cell car go? How long will my fuel cell car last? Summary Current research activities Questions 2

3 Technology Roadmap Passenger car low carbon technology roadmap Automotive Council 3

4 Dream or Reality? Cost Social acceptance Fuel cell vehicles Infrastructure Performance and Durability 4

5 Dream or Reality? Social acceptance Would you buy a fuel cell car? Cost Social acceptance Fuel cell vehicles Infrastructure Performance and Durability 5

6 Dangerous Assumptions 1. This technology is best Therefore, people will have to change their behaviour Argument often used by EV supporters 2. People won t change their behaviour Therefore, this other technology is the best because it can meet customer expectations. Argument often used by H 2 fuel cell or biofuels supporters Both represent an extreme view Neither are likely to be correct What are the arguments and answers? 6

7 Energy Density - Range These must win 7

8 Dream or Reality? Cost Social acceptance Would you buy a fuel cell car? Cost How do we drive down the cost of a fuel cell car? Social acceptance Fuel cell vehicles Infrastructure Performance and Durability 8

9 Power / kw Speed / KPH Decoupling Power And Energy Range of operation for automotive drive cycles are very wide Peak power >> Average power Small amount of energy needed at high powers Average power Time / s (Right) Velocity and power for the JC08 drive cycle and (Left) energy histogram within power bins 9

10 Electrochemical Devices Proton exchange membrane fuel cells High energy density Average power density Average cycle life High cost Lithium-ion battery Average energy density Average power density Average cycle life Average cost Electrochemical double-layer capacitor Low energy density High power density High cycle life Average cost Ragone plot showing the energy and power density of various electrochemical devices 10

11 Fuel Cell Hybrid Vehicles Predicted 2025 powertrain and fuel costs Pure fuel cell vehicle High ICE cost Average ICE cost Low ICE cost Hybrid fuel cell vehicle Offer et al. Energy Policy, 2011, Vol:39, pages:

12 Dream or Reality? Social acceptance Cost Fuel cell vehicles Infrastructure Social acceptance Would you buy a fuel cell car? Cost How do we drive down the cost of a fuel cell car? Infrastructure Where will I get my hydrogen? Performance and Durability 12

13 Fuel And Electricity Costs Ideal locations for EVs are regions with high fuel costs and low electricity costs Denmark Germany Italy Portugal Belgium Netherlands Japan Sweden UK Greece Czech Republic Switzerland Finland Poland France Turkey Norway US Mexico Electricity Electricity cost / $/MWh Households Industry Turkey Norway Italy Netherlands Denmark Greece Finland Belgium Sweden UK Portugal Germany France Switzerland Czech Republic Poland Japan Mexico US Fuel costs / $/L Unleaded Diesel Cost (in USD) of electricity in different countries and cost (in USD) of unleaded and diesel fuel in different countries in IEA. Key world energy statistics.; Fuel Good: Turkey, Norway, Finland Bad: Japan (subsidies) 13

14 Population Density Population density important for placement of hydrogen refuelling stations Netherlands Belgium Japan United Kingdom Germany Switzerland Italy Czech Republic Denmark Poland France Portugal Turkey Greece Mexico United States Sweden Finland Norway Population / Millions Population Population density Population density / people.km -2 Italy Germany Switzerland Belgium France Norway Finland Netherlands Poland Sweden Greece Japan United Kingdom Portugal Czech Republic United States Denmark Mexico Turkey Passenger vehicles per 1000 people 2013 Urban population and population density for different countries and 2011 number of passenger vehicles per 1000 people for different countries The World Bank. Population density (people per sq. km of land area) Available at: Accessed October 10, The World Bank. Urban population Available at: Accessed October 10, The World Bank. Passenger cars (per 1,000 people) Available at: Accessed October 10,

15 UK Refuelling Network UKH2 Mobility Phase 1 results 15

16 UK Refuelling Network HRS network 2015 to 2030 UKH2 Mobility Phase 1 results 16

17 Dream or Reality? Social acceptance Cost Fuel cell vehicles Infrastructure Social acceptance Would you buy a fuel cell car? Cost How do we drive down the cost of a fuel cell car? Infrastructure Where will I get my hydrogen? Performance and Durability How fast will my fuel cell car be? How long will my fuel cell car last? Performance and Durability 17

18 Fuel Cell Degradation PEM fuel cell operating modes and major types of degradation Ryoichi Shimoi, Takashi Aoyama, and Akihiro Iiyama. Development of Fuel Cell Stack Durability based on Actual Vehicle Test Data: Current Status and Future Work. SAE International Journal of Engines, 2(1): , Operating mode Degradation Main causes Start-up Cathode catalyst surface area loss Cathodic reactant gas diffusion deterioration Cathode carbon support corrosion by high potential Load cycling Cathode catalyst surface area loss Cathode catalyst dissolution by potential cycling Idling (low current) Cathode catalyst surface area loss Membrane proton conductivity loss Cathode catalyst dissolution by high potential Chemical decomposition by peroxide attack Cathode catalyst poisoning by membrane fragments Degradation mechanism at FC stack start up (left) and platinum dissolution during load cycling (right) Ryoichi Shimoi, Takashi Aoyama, and Akihiro Iiyama. Development of Fuel Cell Stack Durability based on Actual Vehicle Test Data: Current Status and Future Work. SAE International Journal of Engines, 2(1): , 2009.c 18

19 Fuel Cell Systems Require additional components known as the Balance-of- Plant Delivers air, hydrogen and removes excess heat Components can be slow to react to load changes Blower Humidifier Fuel Cell Stack P T H P T H T T Load bank Hydrogen System Air System Back pressure Control valve P T H P T H Hydrogen Humidifier Recirculation pump Cooling System Nitrogen system Hydrogen supply Nitrogen supply Manual Manual Solenoid Solenoid F Deionising Filter Radiator Fan Fuel cell system component schematic Coolant Pump Flow meter Purge Pressure sensor Thermocouple Relative humidity sensor F P T H 19

20 Transient Performance Response time of electrochemical reaction very fast Response time of Balance-of-Plant can be on the order of seconds Air manifolding, blower inertia Leads to rapid decay of stack voltage and possible local fuel starvation Blower Humidifier Fuel Cell Stack P T H P T H Load bank T T P T H P T H Back pressure Control valve Hydrogen System Air System Hydrogen Humidifier Recirculation pump Cooling System Nitrogen system Hydrogen supply Nitrogen supply Manual Manual Solenoid Solenoid F Deionising Filter Radiator Fan Coolant Pump Flow meter Purge Pressure sensor Thermocouple Relative humidity sensor F P T H (Left) Fuel cell system BOP schematic and (Right) voltage, current and cathode pressures during pulse loads of 75 A 20

21 FC-Supercapacitor Passive Hybrid 9.5 kwe PEMFC with in-house developed Balance-of-Plant system Coupled with a 33 x 1500 F Maxwell supercapacitor pack Blower Hydrogen System Air System Cooling System Nitrogen system Hydrogen supply Nitrogen supply Humidifier Back pressure Control valve Manual Manual Solenoid Solenoid F Fuel Cell Stack P T H P T H T P T H P T H Hydrogen Humidifier Recirculation pump Deionising Filter Radiator Fan Supercapacitors T Coolant Pump Flow meter Load bank Purge Pressure sensor Thermocouple Relative humidity sensor F P T H V Hall effect current sensor HE HE Fuse Contactor 10Ω 310A Fuel cell V HE 310A HE Load bank 50 mm 2 (150A) 10 mm 2 (80A) DC/DC converter DC/DC converter 6 mm 2 (50A) Balance of Plant HE 80A V 24V lead acid battery (Top) Fuel cell system component schematic, (Bottom-right) powertrain component layout and (Bottom-left) picture of system Design and testing of a 9.5 kwe Proton Exchange Membrane Fuel Cell-supercapacitor passive hybrid system Wu et al. International Journal of Hydrogen Energy 39 (15),

22 Voltage / V Efficiency / % Current / A Voltage / V Current / A Fuel Cell Hybrid System Under step loads additional mass transport losses are incurred due to manifolding and compressor inertia effects Passive coupling reduces transient loads on the fuel cell Increase in efficiency of 5% under step loads Pure FC FC-SC (a) Time / s (b) 90 FC current SC current Load current A 50 A 75 A Pulse load amplitude / A (Top) Pure FC mode under 75A 0.2 Hz step loads, (Bottom-right) FC-SC passive hybrid under the same load and (Bottom-left) Comparison of fuel efficiency Design and testing of a 9.5 kwe Proton Exchange Membrane Fuel Cell-supercapacitor passive hybrid system Wu et al. International Journal of Hydrogen Energy 39 (15), FC voltage SC voltage Time / s 22

23 FC frequency Current / A SC frequency Load frequency Real World Load Cycles Reduced peak load for FC Reduced time at no load Supercapacitors operate with zero current average FC current SC current Load current Average SC load Average load Average FC load Peak load Peak FC load Time / s (Left) Currents under a scaled HWFET drive cycle and (Right) current histograms of the same load cycle for the FC, supercapacitor and load cycle Design and testing of a 9.5 kwe Proton Exchange Membrane Fuel Cell-supercapacitor passive hybrid system Wu et al. International Journal of Hydrogen Energy 39 (15), Current / A 23

24 Dream or Reality? Social acceptance Cost Fuel cell vehicles Infrastructure Social acceptance Would you buy a fuel cell car? Cost How do we drive down the cost of a fuel cell car? Infrastructure Where will I get my hydrogen? Durability How fast will my fuel cell car be? How long will my fuel cell car last? Performance and Durability Many challenges but also many opportunities 24

25 Percentage miles on electric Powertrain, fuel and carbon cost / $ One Size Doesn t Fit All 80% of vehicle miles could be electrified at reasonable cost Hydrogen & Fuel Cells Plug-in-Hybrids Mass Market Long Distances Heavy Vehicles Remaining 20% becomes increasingly expensive Battery Electric Advanced Biofuels Plug-in-Hybrids Short Distances Light Vehicles Mass Market Note: Not to scale time Long Distances Heavy Vehicles k 40.0k k k 25.0k Small vehicle Small/Medium vehicle Medium vehicle Large vehicle k 15.0k 10.0k 5.0k Large vehicle Medium vehicle Small/Medium vehicle Small vehicle Battery size / kwh Battery size / kwh 25

26 Current Research Segmented rendering: Yellow = Li-Si Pink = Cu Green = Li Li + Battery Electric Vehicles Module design Performance limitations Novel diagnosis techniques Metres - Engineering Hydrogen fuel cells System design + control Novel low cost configurations Multi-length scale Modelling New materials Physical modelling of Lithium-silicon lithium-ion batteries, batteries hydrogen fuel cells for Metal-air batteries EV and grid Redox flow cells Microns - Science 26

27 Zero Emission Band As featured on BBC breakfast news and Blue Peter Michael Parkes (PhD) showcasing the power of the hydrogen fuel cell generator at the H2Supergen BBQ meeting at Imperial College 27

28 Thank You For Listening Electrochemical Science and Engineering Group Dr. Billy Wu Lecturer in the School of Design Engineering Head of Division for Autonomous Systems and Advanced Engineering Imperial College London 28