fuel cell friedrich new - electromobility · a320 d-atra development ... new system for flight...
TRANSCRIPT
Folie 1Direct Hybrid > Prof.-Dr. K. A. Friedrich > 2011-09-26
Fuel cell systems for mobile applications: a comparison of automotive and aeronautic system design
J. Kallo, J. Ungethüm, K. A. Friedrich
Folie 2
Content
• General introduction electromobility
• Synergies between terrestrial transport and aircraft application
• Multifunctional fuel cell system
• Emission-free taxiing of aircraft
• Efficient electric drives and “direct hybridization”
• System Modeling
Folie 3
Efficiencies
Typical car efficiency (Tank to Wheel):Internal combustion engine: 20 – 25 %
Fuel cell electrical drive: 40 – 50 %
Battery electrical drive: 70 – 80 %
fuel heat movement electricity
fuel electricity
OH
H
chemical energy electricityelectricity
Secondary battery
Folie 4
Efficiency Comparison of Automotive Power Trains
Based on Well-to-Wheel studies of European and Japanese Sources: Concawe, EUCAR, JRC und JHFC
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100
50
0
CO
2 E
mis
sion
s / g
CO
2eq k
m-1
250200150100500Energy Comsumption Well-to-Wheel / MJ (100 km)-1
GasolineDiesel
Hybrid (gasoline)Hybrid (Diesel)
Fuel Cell Powertrainwith 100% H2 from natural gas
Battery drivewith power from 100% EU grid
Fuel Cell Powertrainfrom 100% renewable H2
Battery Powertrainfrom 100% renewable power
Technology Change
Gasoline Japan (JHFC)
Diesel Japan (JHFC)
Hybride Gasoline Japan
Fuel Cell Japan (nowadaysand future)
Battery Japan (Power Mix)
Folie 5
Motivation for Fuel Cell System Application
Ecological and Economical A/C Operation AspectsEcological Aspects:
Emission reductionHigher fuel economyNoise reduction
Economical Aspects:Weight ReductionLow MaintenanceMission ImprovementsElimination of RAT and APUBattery ReductionAPU ~ 20 %
idle ~ 10 %APU ~ 40 %
idle ~ 50 %
Folie 6
Emergency Power
Fuel Tank inerting system
Auxiliary Power
Batteries
Ground SupportEquipment Water Refilling Truck
No pollutants :(HC, NOx, CO, SO2)Less noise
Fuel and CO2:Reduced fuel burn= lower CO2 emissions
Hydrogen supplied fuel cell
Low Emissions System : Fuel Cells
Folie 7
FCEPS – Fuel Cell Emergency Power SystemTest Flight
Provides immediately Power after failure of power generationIntegration into the aircraft body -> independent of flight velocityBenefits compared to Ram Air Turbine:
• Possible weight reduction without influence on flow resistance• Switch-off and reactivation of system is possible • Maximum power independent of flight phase• (flight velocity and flight height)• Less maintainance (no moving parts)
Constant Power during acceleration in flight (30.000ft)!
Folie 8
Inclination Vibrations Temperature Low pressure
Integration and Test in A320 D-ATRA
Development Multifunctional Fuel Cell SystemTechnology Platform
Flight certified architecture and componentsABD 100 und DO160E
Load calculation for mechanical set up
Qualification tests and documentation
Folie 9
Fuel Cell Technology Transfer to Aircraft Application
Mechanical Strenght Simulation
Aircraft ApplicationFunctionality, Architecture, BOP
FC System from Transport Application
Airworthy technology development platform
Folie 10
New System for Flight Testing Fuel Cell System
Air Fuel Cell System for multifunctional use: Power > 12.5 kW
Water generation and inerting function demonstrated
Folie 11SEITE 11
Multifunctional Fuel Cell System
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0.0 Wat
er P
rodu
ct @
Cat
hode
/ kg
kW
h-1
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LambdaInert @ 10°CLambdaInert @ 1°CLambdaref @ 10°CLambdaref @ 1°C
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Oxy
gen
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n / v
ol%
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Lambdaref LambdaInert1 LambdaInert2 Inerting Requirement
System of 12 kW electrical power with aircraft relevant design shows inert gas generation (oxygen content < 12 Vol.%) and water generation
Major importance is air stoichometry
Modelling for flight operation according to Federal Aviation Administration (FAA) publications
Folie 12
Overview emission free taxiing with fuel cell and electric nose wheel drive
Multifunctional fuel cell system in cargo bay- Output Voltage 300VDC
Fully integrated e-NWD
DC/DC+
DC/AC
ControlBox and Data
Aquisition
High Torque 11.000Nm
Folie 13Direct Hybrid > Prof.-Dr. K. A. Friedrich > 2011-09-26
Hybridisation Basics
Power and energy source with highenergy densitye.g.. Fuel Cell (or ICE + Generator)
Power and energy source with highpower densitye.g.. Battery
Load
Hybridized Power FC + Batt
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Time [s]
Pow
er [W
]
Combined Power FC + Batt [W]Power FC [W]
Hybrid system with 50 kW power12 kWh Li-Ion capacity, 33 kWh H2 electrical energy (50 %)
Battery shut down
Antares System 2nd Generation
Folie 14Direct Hybrid > Prof.-Dr. K. A. Friedrich > 2011-09-26
Concept of the direct hybrid
Fuel Cell Stack
ElectricLoad
MDC
DC
DC
AC
Battery Pack
Conventional hybrid systemsneed one or two DC/DC converterfor potential separation DC/DC converter are expensiveDC/DC converter reduce system efficiency
Fuel Cell Stack
ElectricLoad
MDC
DC
DC
AC
Battery PackDC
DC Direct hybrid systems donot use any DC/DC converterPotential separation is managed by two diodesNo active current control isnecessaryLoad balancing is achieved bythe polarization characteristicsof fuel cell stack and batteryRecharge is achieved by asingle MOSFET / IGBT
Advantages of the direct hybrid systemNo inductanceHigh efficiencyLower costLight weightReliableMostly passive elements
Disadvantages: no fixed potential
Folie 15Direct Hybrid > Prof.-Dr. K. A. Friedrich > 2011-09-26
Fuel cell stackSchunk FC-42
Electric loadEL9080-200HP
Li-ion battery packA123 ALM12V60
MOSFET
DiodeCurrent
transducer
Voltmeter
Fuse
Relay
Relay
Switch
The direct hybrid test system at the DLR (small scale)
Stack: Schunk FC-42nominal power: 360Wnominal current: 15Anominal voltage: 24Voperating temperature: 70°Coperating pressure: atmospherecooling medium: air
Battery: A123 ALM12V60 (2s)two blocks in serialnumber of cell per block: 4nominal capacity per block (1C):
4.32Ahnominal voltage per block: 12Vmaximal discharge current: 80A
Folie 16Direct Hybrid > Prof.-Dr. K. A. Friedrich > 2011-09-26
Fuel Cell – Battery - Direct hybrid principle – Load phase
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Current / A
Volta
ge /
V
BatteryFuel cell
Fuel
cel
l onl
yH
ybrid
Fuel Cell and Battery characteristics
Operating at voltages UFC > UOCV,Batt- Load delivered by fuel cell only
Operating at voltages UFC < UOCV,Batt- Load delivered by fuel cell and battery
UOCVBatt
Folie 17Direct Hybrid > Prof.-Dr. K. A. Friedrich > 2011-09-26
Fuel Cell – Battery - Direct hybrid principle - Recharge
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Current / A
Volta
ge /
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BatteryFuel cell
Fuel
cel
l onl
yH
ybrid
Fuel Cell and Battery characteristics
Operating at voltages UFC > UOCV,Batt- Load delivered by fuel cell only
UOCV,Batt
Max. battery voltage UBatt,Max
Rec
harg
e ar
ea
Rechargearea
Operating at voltages UBattMax>UFC>UOCVBatt- Load and recharge current delivered by fuel cell if recharge switch „on“
Folie 18Direct Hybrid > Prof.-Dr. K. A. Friedrich > 2011-09-26
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Time / min
Volta
ge /
V
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Cur
rent
/ A
Load_UBattery_UFuel cell_ULoad_IBattery_IFuel cell_I
Voltage
Current
Quasi static behavior of the hybrid system
At low electric load power isdelivered by fuel cell only
at higher load fuel cell voltage equals battery voltage, both systems deliver energy
fuel cell power is limitedas its voltage cannot drop below battery voltage
FC + Batthybrid operation
FConly
Folie 19Direct Hybrid > Prof.-Dr. K. A. Friedrich > 2011-09-26
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Time / s
Volta
ge /
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Cur
rent
/ AU Load
U BatteryU Fuel cellI LoadI BatteryI Fuel cell
current
voltage
Dynamic behaviour of the direct hybrid system
fc only fuel cell and batteryDynamic behaviour wastested using anintermittent load distributionElectric load is changed with± 165A per second(<100ms step)Afterwards it is kept constantfor 30 seconds
load balancing is done automaticallyonly fuel cell delivers current at low loadboth fuel cell and battery delivers current higher loadbattery limits current slope dI/dtbattery delivers current
after fast load step-up
Folie 20Direct Hybrid > Prof.-Dr. K. A. Friedrich > 2011-09-26
Dynamic behaviour of the direct hybrid system
For medium load battery delivers current only for a short periodFor higher load battery keeps delivering currentFor a few 10th of a second current is delivered fromdouble layer capacity and gas volume effectIn any case fuel cell voltage is kept in acceptable rangeUcell> 580mV
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Time
Volta
ge /
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Cur
rent
/ A
Load_UBattery_UFuel cell_ULoad_IBattery_IFuel cell_I
Current
Voltage
1 s
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Time
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ge /
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rent
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Load_UBattery_UFuel cell_ULoad_IBattery_IFuel cell_I
Voltage
Current
1 s
Folie 21Direct Hybrid > Prof.-Dr. K. A. Friedrich > 2011-09-26
Direct hybrid – high dynamic and cycling behaviour
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Time / s
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Cur
rent
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LoadBatteryFuel cellLoadBatteryFuel cell
Demonstration of cyclic operation at the frequency of 2.5Hz and 0% - 100% - 0% fuel cell load in <25ms
- Fuel cell “buffer” effect done by double layer capacitance and gas volume effect- Battery low voltage “safety net” - stable continuous operation
Folie 22Direct Hybrid > Prof.-Dr. K. A. Friedrich > 2011-09-26
20110711_4
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Gross power / W
Pow
er lo
ss /
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Pow
er lo
ss /
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s po
wer
/ %
Power lossPower loss at diodePower loss/Gross power(%)
Diodes
ContactsRelaysWires…
Power losses of the direct hybrid system
Power losses originates byDiodesContact resistanceRelaysWires…
Diode losses raise onlylinear with gross powerDiode losses areapproximately 1.5% of gross power
At nominal power auxiliary losses are additional 2.5%of gross power
Folie 23Direct Hybrid > Prof.-Dr. K. A. Friedrich > 2011-09-26
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Current / A
Volta
ge /
V
max. Fc current16A (per design)
Fc 44 cells
Fc 42 cells
Fc 40 cells
Umin Fc 42 cells
Umin Fc 44 cells
Umin Fc 40 cells
Bat 9 cells
Bat 8 cells
Bat 7 cells
20110708_11
Design of the direct hybrid system
Characteristic of load balancing is fixed by designVoltage range of battery packdefines the range of hybridoperation 8-cell battery / 42 cell Fc hybrid: hybrid operation between UFc,min = 24 … 26.4V = UBat,OCVthe 42-cell FC-Stack delivers ~12.5 … 16A in that range9-cell battery / 44 cell Fc hybrid:hybrid operation between UFc,min = ~25 … 29.7V = UBat,OCVthe 44-cell FC-Stack delivers ~9.5 … 16A in that range
Flexible design of hybrid characteristicdepending on application
Folie 24Direct Hybrid > Prof.-Dr. K. A. Friedrich > 2011-09-26
20110708_11
System characteristics at variable battery SOC
The battery voltage depends on current and SOCat 60A battery current:
24.5V at 80% SOC 23.5V at 20% SOC
As fuel cell polarization curve ismuch steeper at high load thanbattery curve, fuel cell currentchanges only slightly with SOC
~15A at 80% SOC, at full load~14A at 20% SOC, at full load
Fuel cell behaviour, range and dynamic is mostly independentfrom battery SOC
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Current / A
Volta
ge /
V
min. Bat voltageat 80% SOC~24.5V
max. Fc currentat 80% SOC
max. Fc currentat 20% SOC
Fc 40 cells
Bat 80% SOC
Bat 50% SOC
Bat 20% SOC
min. Bat voltageat 20% SOC~23.5V
max. Bat current60A (per design)
Folie 25Direct Hybrid > Prof.-Dr. K. A. Friedrich > 2011-09-26
Direct hybrid – Load and Recharge Phase
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Time / min
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Cur
rent
/ A
LoadBatteryFuel cellLoadBatteryFuel cell
Voltage
Current
Load Phase
Load + Battery Recharge Phase
- Max battery rechargecurrent defined by number of fuel cells and batteries
- Battery overvoltage protection circuit
Efficient (up to 95%) and reliable recharging process
Folie 26Direct Hybrid > Prof.-Dr. K. A. Friedrich > 2011-09-26
Hybridized Power FC + Batt
0
5000
10000
15000
20000
25000
30000
35000
40000
0 1000 2000 3000 4000 5000
Time [s]
Pow
er [W
]
Combined Power FC + Batt [W]Power FC [W]
DLR – direct hybrid – big scale up to 50 kWel.
Direct Hybrid FC + Battery (Li Ion)Advantages:
- Power boost for critical situations- Fuel cell in max. efficient mode- Very low cost components!
Direct coupling FC + BattBattery shut down
Input for battery research in these areas:- Safety (overvoltage)- Cyclability (durability)- Thermal management - Efficiency (Battery Management System) Hybrid system with 12kWh Li-Ion
Target 3-5kWh LiFePO4
Folie 27Direct Hybrid > Prof.-Dr. K. A. Friedrich > 2011-09-26
Hybrid Fuel Cell / Battery SystemsUpgrade Antares DLR H2 to Antares DLR H3
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Stromstärke [A]
Span
nung
[V]
U-I-Kennlinie - 660mbarU-I-Kennlinie - 700mbarU-I-Kennlinie - 806mbarU-I-Kennlinie - 1000mbar
Current [A]
underpressure behaviour
Hybridization
Build up of an improved plane with endurance from 15 to 50 h- third generation fuel cells 35 kWel.- Hybridization improvement > 55 kWel.- improved fuel tank capacity- 30% efficiency gain (motor
and aerodynamics improvement)- Payload up to 250kg (operational)
volta
ge [V
]
Folie 28Direct Hybrid > Prof.-Dr. K. A. Friedrich > 2011-09-26
Thank you for your attention!
Acknowledgement: DLR Team, Airbus Team and BMWi for funding