The document analyzes the costs and benefits of adding a fuel cell to enhance the range of a battery electric vehicle (BEV). Simulations show that a BEV has limited range due to battery weight and energy consumption. A small fuel cell can significantly increase range but also increases emissions. With future cost reductions, a downsized fuel cell-enhanced BEV could be cost competitive with conventional vehicles. However, consumer acceptance currently depends on willingness to pay more or change driving behavior. The optimal battery-fuel cell combination will depend on trip length and other factors.

1. The Costs and Benefits of a Fuel Cell
Enhanced Battery Electric Vehicle
CEEN-596 Final Project
By René Lipp
December 12, 2011

2. Outline
• Introduction
• Simulation Model
• Simulation Results
• Conclusion
2

3. Nissan Leaf
Source: www.nissan.ca/LEAF 3

4. Nissan Leaf
• Cost: $27,700
(After Incentives)
• Vehicle Mass: 1,520kg
• Top Speed: 150 km/h
• Traction Motor: 80kW
(280Nm Torque)
• Battery Capacity: 24kWh
• Energy Consumption:
21.1 kWh/100km
(2.2 L / 105 mpg equiv.)
• Range: 100-150 km’s
Source: www.nissan.ca/LEAF 4

5. Honda Clarity
Source: http://automobiles.honda.com/fcx-clarity/
Large load
following
100kW FC
sized to meet
peak power
requirements
Small Battery
pack for
regenerative
braking &
acceleration
5

6. Fuel Cell (FC) ‘Enhanced’ Battery
Electric Vehicle (BEV)
• FC & BEV’s both have the potential to
significantly reduce vehicular CO2 emissions
but FCEV’s are extremely costly and BEV’s
have a limited range.
• Taking a different approach; a small FC is
added to ‘enhance’ the performance of BEV.
6

7. Battery Electric Energy Storage
• Typically 80% Efficient
• Electricity Cost: $0.12/kWh1 (≈1/3rd of Gasoline2)
• 0.14 kWh/kg (≈1/25th of Gasoline)
1 $0.10/kWh and a 85% charger efficiency
2 $1/L untaxed at conversion efficiency of 25%
BATTERY
e-
e-
7

8. Hydrogen FC Energy Storage System
• Typically 25% Efficient
• Fuel Cost: $0.26/kWh1 electricity equiv.
• 14.8 kWh/kg H2 fuel (≈x105 Battery)
• 110-3,300 g/kWh CO2 equiv.
(Compared to 950 g/kWh2 CO2 equiv. for Gasoline)
1 $4.50/kg Hydrogen and a cell efficiency of 50%
2 http://www.ec.gc.ca/ges-ghg/default.asp?lang=En&n=AC2B7641-1#section2
co2
(From CH4 Reforming Only)
STORAGEor
CH4 e-
H2
STORAGE
ELECTROLYIS
or
REFORMING
e-
H2
F.C.
e-
Storage
Storage
8

9. The Costs and Benefits of a Fuel Cell
Enhanced Battery Electric Vehicle
Simulation Model

10. Governing Equations
• 𝐹𝑔 = 𝑀𝑔 sin 𝛼
• 𝐹𝑟 = 𝑀𝑔0.01 1 +
𝑉
160
cos 𝛼
• 𝐹𝑎 =
1
2
𝜌𝐴 𝑓 𝐶 𝐷
𝑉−𝑉 𝑤
3.6
2
•
𝑑𝑉
𝑑𝑡
=
𝐹𝑡− 𝐹𝑟+ 𝐹𝑎+ 𝐹𝑔
𝛿𝑀
𝑚
𝑠2
Fg + Fr + Fa
Mg
αMg sin(α)
Mg cos(α)
10

11. Idealized Motor Efficiency Curve
0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
100%
0 1000 2000 3000 4000 5000 6000 7000 8000 9000 10000
MotorEfficiency
Motor Speed [rpm]
Lower Efficiencies
at Lower Speeds
11

12. Typical Lithium-Ion Battery Efficiency Curve
60%
65%
70%
75%
80%
85%
90%
1 3 5 7 9 11 13 15 17 19
'C' Rate
Efficiency
Decreases with
Load
12

13. Powertrain Model Schematic
Motor
e- H2
FC
Tank
e-
Battery
e-
e-
13

14. Vehicle Model Parameters• Vehicle Base Mass: 1,125kg (1,500kg w/Batteries)
• Top Design Speed: approx. 150 km/h
• Rolling Resistance Coefficient: 0.01
• Aerodynamic Drag Coefficient: 0.3
• Frontal Area: 2.5m2
• Transmission Efficiency: 90%
• Traction Motor: 100kW (285Nm Torque)
• Max. Motor Speed: 10,000rpm
• Motor Efficiency: 90% Max.
• Tire Radius: 0.305m [12”]
• Wheel Base: 2.7m (approx. 60% Front Brake Distribution)
• Rated Battery Capacity: 30kWh (Baseline)
• Useable Battery Capacity: 80-20% Rated Capacity
• Fuel Cell Power Density: 0.8 kW/kg
• Hydrogen Fuel Tank: 15 kg/kg H2 fuel (40L/kg H2) at 70MPa
• Hydrogen Fuel Storage: 5 kg max.
14

15. EPA Urban Drive Cycle
0
10
20
30
40
50
60
70
80
90
100
0 200 400 600 800 1000 1200 1400
VehicleSpeed[km/h]
Time [s]
1,369 second (22min : 49sec), 12.0 kilometres, 31.5 km/h avg. speed
‘Stop-and-Go’ Traffic
15

16. Vehicle Power Demand Curve
0
10
20
30
40
50
60
0 200 400 600 800 1000 1200 1400
VehiclePowerDemand/Supply[kWe]
Time [s]
Motor Demand ReGenerative Braking Average
Includes transmission and
motor efficiencies but not
energy storage efficiencyPeak Power
Demand
Average Power
Demand
16

17. Battery Power Demand Curve
-70
-60
-50
-40
-30
-20
-10
0
10
20
0 200 400 600 800 1000 1200 1400
EnergyStoragePower[kW]
Time [s]
Regenerative Braking
Supplied to Vehicle
Drive Motor
17

18. EPA Highway Drive Cycle
765 second (12min : 45sec), 16.5 kilometres, 77.7 km/h avg. speed
0
10
20
30
40
50
60
70
80
90
100
0 100 200 300 400 500 600 700 800
VehicleSpeed[km/h]
Time [s]
18

19. Vehicle Power Demand Curve
0
5
10
15
20
25
30
35
40
45
0 100 200 300 400 500 600 700 800
VehiclePowerDemand/Supply[kWe]
Time [s]
Motor Demand ReGenerative Braking Average
Includes transmission and
motor efficiencies but not
energy storage efficiency
19

20. Vehicle Power Demand Curve
0
5
10
15
20
25
30
35
40
45
0 100 200 300 400 500 600 700 800
VehiclePowerDemand/Supply[kWe]
Time [s]
Motor Demand ReGenerative Braking Average FC
Includes transmission and
motor efficiencies but not
energy storage efficiency
15kW FC sustains the
Battery’s energy level
20

21. Effect of Grade on a BEV
Road Angle
(Grade)
Urban Drive Cycle Highway Drive Cycle
Avg.
Power
[kW]
Energy
Consumption
[Wh/km]
Regenerative
Braking
Avg.
Power
[kW]
Energy
Consumption
[Wh/km]
Regenerative
Braking
-20°
(-36.4%)
-14.5 -461 100% -16.5 -302 100%
-15°
(-26.8%)
-11.7 -372 100% -23.1 -298 100%
-10°
(-17.6%)
-7.8 -248 100% -18.1 -234 100%
-5° (-8.7%) -2.7 -84 100% -7.1 -92 100%
Flat 6.3 200 9.3% 15.7 203 2.3%
5° (8.7%) 22.5 713 0.7% 59.3 764 0.1%
10° (17.6%) 40.2 1,275 0%
Exceeds Motor Power Rating15° (26.8%) 58.6 1,858 0%
20° (36.4%) 76.8 2,437 0%
21

22. Key Points
• The average power demand of a vehicle is
significantly less than its peak demand;
– Thus a FC could be downsized to meet this
average power demand whilst,
– The battery provides peak load-following power.
22

23. The Costs and Benefits of a Fuel Cell
Enhanced Battery Electric Vehicle
Simulation Results

24. BEV Energy Consumption
0
100
200
300
400
500
600
700
800
100 150 200 250 300
EnergyConsumptPenaltykm]
Range [km]
BEV
24

25. BEV Range Limitations
-
2,000
4,000
6,000
8,000
10,000
12,000
14,000
16,000
0
50
100
150
200
250
300
350
400
0 250 500 750 1000
VehicleMass[kg]
VehicleRange[km]
Battery Capacity [kWh]
Range Mass
25

26. Trade-off Btw. Battery Efficiency and Weight
0
100
200
300
400
500
600
700
800
100 150 200 250 300
EnergyConsumptPenaltykm]
Range [km]
BEV 1 to 5kW FC-BEV
Higher Battery
Efficiency Dominates
Battery Weight
Penalty Dominates
26

27. Vehicle Incremental Costs: 250km Range
$129,750
$60,000
$18,750
$11,250
$2,500
$5,000
$7,500
$500
$1,000 $1,000
$7,325
$3,375
$1,050
$625
$6,025
$10,100
$11,150
$45
$170
$260
$285
$-
$20,000
$40,000
$60,000
$80,000
$100,000
$120,000
$140,000
$160,000
0/173 BEV 2.5/80 FCBEV 5/25 FCBEV 7.5/15 FCBEV
IncrementalVehicleCost
Fuel Cell [kW] / Battery [kWh]
CO2 Tax
Fuel
Electricity
Tank
FC
Battery
Battery: $750/kWh
FC: $1,000/kW
Tank: $500/kg H2
Electricity: $0.10/kWh (150,000km's)
Fuel: $10/kg H2 (150,000km's)
CO2 Tax: $25/Tonne
O&M: Not Included
27

28. Key Points
• A long-range BEV isn’t practical;
– The low energy density of the battery limits the
vehicles range.
– It can be more cost effective to add a small FC,
than it is to increase the size of the battery.
• Next Step; A ‘side-by-side’ comparison.
28

29. FC-BEV Energy Consumption
200
130
120
0
50
100
150
200
250
300
0/30-BEV 25/15-FCBEV
Energy[Wh/km]
Fuel Cell [kW] / Battery [kWh]
Fuel Cell (Hydrogen)
Battery (Electricity)
90km
Range
555km
Range
(Baseline)
29
Dependanton%
DailyTripDistribution

30. FC-BEV CO2 equiv. Emissions
6
4
31
-
5
10
15
20
25
30
35
40
0/30-BEV 25/15-FCBEV
CO2Emissions[g/km]
Fuel Cell [kW] / Battery [kWh]
Hydrogen (SMR)
Electricity
25 gCO2/kWh
10kgCO2/kg H2
Note: 2011 Toyota Prius @ 3.7 L/100km equates to 85 g/km (Tank-Wheel)
30

31. “How Much Range is Enough Range?”
1995 NTPS Daily Driving Distances Distribution
≈90km
(≈250km)
31

32. Accepting the Range Limitations of BEV’s;
Public Charging Stations Depends On:
Source: http://www.ecomagination.com/technologies/wattstation
• Willingness to change
driving behaviour
• The development of
supporting infrastructure
32

33. Accepting the Range Limitations of BEV’s;
Battery Swapping Stations Depends On:
Source: : http://www.betterplace.com
• Willingness to change
driving behaviour
• The development of
supporting infrastructure
• The availability of
alternative transportation
options (if need be)
33

34. $7,500
$3,750
$2,500
$375
$3,525
$2,300
$2,050
$90
$515
$-
$2,000
$4,000
$6,000
$8,000
$10,000
$12,000
$14,000
0/30-BEV 25/15-FCBEV
IncrementalVehicleCost
Fuel Cell [kW] / Battery [kWh]
CO2 Tax
Fuel
Electricity
Tank
FC
Battery
90km
Range
Total Additional Cost
$375 (or 3%)
Future Target Cost Considerations
Based Upon: Battery: $250/kWh, FC: $100/kW, Tank: $75/kg H2, Electricity: $0.10/kWh (150,000km's)
Fuel: $4.5/kg H2 (150,000km's), CO2 Tax: $100/Tonne, O&M: Not Included
34

35. Future Target Cost Considerations
$7,500
$3,750 $3,000
$7,000
$11,750
$750
$2,500
$7,500
$7,500
$7,500
$7,500
$3,525
$2,300
$2,150
$3,175
$4,000
$2,050
$2,175
$1,075
$575
$5,525
$-
$5,000
$10,000
$15,000
$20,000
$25,000
$30,000
0/30-BEV 25/15-FCBEV 75/12.5-32kmPFCEV 75/28-64kmPFCEV 75/47-96kmPFCEV 75/2.5-HFCEV
IncrementalVehicleCost
Fuel Cell [kW] / Battery [kWh]
CO2 Tax
Fuel
Electricity
Tank
FC
Battery
90km
Range
Based Upon: Battery: $250/kWh, FC: $100/kW, Tank: $75/kg H2, Electricity: $0.10/kWh (150,000km's)
Fuel: $4.5/kg H2 (150,000km's), CO2 Tax: $100/Tonne, O&M: Not Included
Typical Economy Class ICE &
150,000km Fuel Costs
(untaxed @ $1/L )
35

36. Conclusion
• A long-range BEV isn’t practical.
• Enhancing a BEV with the addition of a FC can
significantly increase the vehicles range;
– However this comes at the cost of increased CO2
emissions.
• If future target cost reductions of 1/3rd for batteries
and 1/10th for fuel cells are meet;
– A downsized FC-BEV would be highly cost competitive.
• In the near term, acceptance of low-emissions vehicles
depends on the consumers willingness to pay more
and/or change their driving behaviour.
36

37. Future Outlook:
• Battery Electric and Fuel Cell vehicle technologies will
converge.
• The optimum combination of Battery+Fuel Cell will
depend on driving behavior;
Battery FC
Higher
Efficiency
Higher
Energy
Density
Mostly Shorter Trips Mostly Longer Trips
Thank you; Eric Mazzi, P.Eng., Ph.D. (Project Sponsor)
37