Development of Sensors for AutomotivePEM-based Fuel Cells
DOE Agreement DE-FC04-02AL67616
DOE Hydrogen and Fuel Cells 2004 Annual Merit ReviewMay 26, 2004
UTC FC Series 200 - 50 kW PEM
MATERIALS
NEXTECH
Nancy Garland - DOE
Tom Clark – UTC FC
This presentation does not contain any proprietary or confidential information
2
Sensors for Automotive PEM Fuel Cells – Objectives
Sulfur
sensor
NH3, T, flow
rate sensors
NH3, T, flow
rate sensors
Sulfur
sensor
NH3, T, flow
rate sensors
NH3, T, flow
rate sensors
•Chemical sensors
–Process streams: before, in, and after reformer, before and in fuel cell stack: CO, H2, O2, H2S, NH3; Safety [H2].
•Physical Sensors
–Temperature, pressure, relative humidity, flow, P
Develop a technology and commercial supplier base for physical and chemical
sensors required to optimize the operation of PEM fuel cell power plants for
automotive applications with path to low cost (<$20 / sensor) at 500k qty.
3
Sensor Program Team Responsibilities
• Sensor development program utilizes a team approach
– UTRC for physical and chemical sensor evaluation and program coordination
– Illinois Institute of Technology (IIT) for chemical sensor evaluation
– Advanced Technical Materials (ATMI) for MEMS sensor development
– NexTech Materials for electrochemical and solid state sensor development
Team
Member
T P RH flow O2 CO H2 SO2 H2S NH3 Technological Expertise /
Responsibility
UTC FC X X X X X X X X X X Testing on S300
Breadboard
UTRC X X X X X X X X X X Testing in reformate
simulator
ATMI X X X X Develop Using MEMS
Silicon Microhotplate
IIT X X X X X X X X Testing in Benchmark
Facility
NexTech X X X X Develop Using Solid State
Electrochemical
4
Sensor Program Team Structure
• Continuous interaction among team members
• ATMI, NexTech develop sensors, IIT and UTRC test and aid in optimization
Sensor Suite
to DOE
Sensor Test in
S300 PEM Plant
MEMS Sensor
– ATMI
H2, H2S, SO2, NH3
Solid State/Chem.
Sensor – NexTech
CO, H2S, SO2, NH3
Physical Sensor
Evaluation –
UTRC
Benchmark
Sensor Test –
IIT
Sensor Test &
Refinement –
UTRC
Program Lead
And Evaluation
UTC FC/UTRC
Sensor Suite
to DOE
Sensor Suite
to DOE
Sensor Test in
S300 PEM Plant
Sensor Test in
S300 PEM Plant
MEMS Sensor
– ATMI
H2, H2S, SO2, NH3
MEMS Sensor
– ATMI
H2, H2S, SO2, NH3
Solid State/Chem.
Sensor – NexTech
CO, H2S, SO2, NH3
Solid State/Chem.
Sensor – NexTech
CO, H2S, SO2, NH3
Physical Sensor
Evaluation –
UTRC
Physical Sensor
Evaluation –
UTRC
Benchmark
Sensor Test –
IIT
Benchmark
Sensor Test –
IIT
Sensor Test &
Refinement –
UTRC
Sensor Test &
Refinement –
UTRC
Program Lead
And Evaluation
UTC FC/UTRC
Program Lead
And Evaluation
UTC FC/UTRC
5
Sensors for Automotive Fuel Cells Plan
Calendar Year2002 2003 2004 2005
2.3 Benchmark Facility Testing
1.0 Physical Sensor Evaluation
2.1 Electrochemical Sensor Development
2.2 MEMS Sensor Development
2.5 S300 Gasoline PEM Fuel Cell Testing
NexTech
IIT
ATMI
UTRC /UTC FC
Legend
2.4 Simulated ReformerStream Testing
3.0 Project Management and Reporting
Done except for Honeywell
Sensor Survey completed
6
Sensors Program Financial Status
•Total cost: $3.7MM; DOE cost: $3.0MM (80%) UTC Cost Share: $0.7MM (20%)
•Total expended to date: $1.6MM
•Duration: April 2002 – March 2005
0
500
1000
1500
2000
2500
3000
3500
4000
Nov-01 Feb-02 May-02 Sep-02 Dec-02 Mar-03 Jun-03 Oct-03 Jan-04 Apr-04 Aug-04 Nov-04 Feb-05 May-05
Date
PV
- $
k
UTRC IIT NexTech ATMI Total Plan Total Expenditure
7
H2 Safety Issues Associated with Project
• Use of H2 in laboratory environment
– Flammable gas detectors located in laboratory; relay opens and turnsoff power to solenoid valves on H2 supply at 10% of LEL
– LabView-based control program senses alarm, shuts off all othergases and purges all gas lines with N2
– All valves used in experiment are explosion-proof
– Pressure relief valves used in all piping to prevent over-pressurizationof components
• Sensor technology– Heated sensing elements can provide an ignition source; therefore the
detection element must be separated from the gas stream by a flash-arrestor (porous plate) to prevent ignition of the bulk gas
8
PEM Fuel Cell Gas Stream Simulators at UTRC & IIT
UTRC test rig with dual chambers
IIT test rig
Test chamber(25 - 450°C)Pressure: 1-4 atm
Both test rigs operate under
LabView control for 24/7
operation (data acquisition
and test matrix completion)
9
Sensor Evaluation Status at UTRC
• Physical Sensors
– Sensors for T, P, P, Relative Humidity (RH), and Flow evaluated in PEM fuel
cell simulator in near-condensing flow regime
• State-of-the-art physical sensors meeting program needs selected
• Chemical Sensors
– First round of sensor testing and qualification completed
– Multiple H2 sensors evaluated for sensitivity, selectivity, and performance
– Possible extension of the testing effort beyond April 2005 being considered in
order to accommodate field testing requested by Honeywell
Lei Chen and Brian Knight
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Physical Parameter Sensors Results
Responsefluctuation due tocondensation
Most costeffective
Thermaldissipation
Flow
Improve recoveryfrom condensingflow regime
0 to 180 °C, 0-100% RH
Polymercapacitive
(Panametrics)
RH
May be massproduced andminiaturized
Silicon based ICcompatiblefabrication.
Strain gauge
(Druck)Pressure
Response timeneedsimprovement
0 to 250 °C,
-40 to 750 °C
ThermistorTemperature
DevelopmentNeeds
PositiveAttributes
OperatingPrinciple
Sensor
•UTRC researched and tested multiple physical
sensors; most promising tabulated below
11
• IIT evaluated over 70 H2 sensing technologies
• Tiered approach used to evaluate sensor technologies– Gas concentration, operating temperature, water vapor pressure
– Effect of pressure, other background gases
– Long-term testing
• Hydrogen Sensors (Reformer)-H2 Scan, Makel Engineering, ATMI, KSC NASA
• Hydrogen Sensors (Safety Application)-H2 Scan, Applied Sensors, Makel Engineering, ATMI, Figaro, TransducerTechnology, Inc., Argus Group, Nemoto Environmental Technology, AppliedNanotech
• Carbon Monoxide Sensor-NexTech Materials
Benchmark Testing of Viable Sensor
Technologies
Joseph R. Stetter, William R. Penrose, William Buttner, and Kapil Gupta
(Sensors currently available are listed in blue)
12
Literature search and review (for fuel cell sensors and H2/CO sensors)
Researched and short listed tentative companies, based on ourrequirement specifications, vendor products and application
Evaluated the survey responses and accordingly sent out formalinvitations for evaluation of sensors
Now acquiring sensors- NDAs/other formalities
Testing acquired sensors and updating Sensor research DatabaseIntelligent Optical Systems, NASA/KSC/ASRC, NGK
Contacted the companies and sent out sensor survey templates
Process for Selection of Viable Sensor
Technologies
SSTUF: Hydrogen Sensor Response (0.5 to 8%) in air
Single Data Run
- Sensitivity Curves obtained for different pressures at 22oC
- Automated Pressure Control, Flow Control and Concentration
- Capabilities also include Temperature Control and Humidity Control
-0.2
0
0.2
0.4
0.6
0.8
1
1.2
1.4
0 50 100 150 200 250 300
Time (minutes)
1 ATM 2 ATM 3 ATM
PH2 Dependence
(next slide)
Example of Shared Sensor Testing User
Facility Data
Hydrogen Sensor Response (0 to 0.2 atm) in air
Sensor Sensitivity is often controlled by Partial Pressure
of H2 (not %H2)
0
0.2
0.4
0.6
0.8
1
1.2
1.4
1.6
0 0.04 0.08 0.12 0.16 0.2
Partial Pressure Hydrogen (atm)
Sen
so
r R
esp
on
se
Ptotal = 3 atm
Ptotal = 2 atm
Ptotal = 1 atm
Results of IIT H2 Safety Sensor Testing in Air
15
• Targets
– [H2]: 0-10%; Temp: –30 to 80oC, Response time: < 1 s; Humidity: 10-98%; Selectivity from hydrocarbons; Accuracy: 5%; Lifetime:5 yrs
• Approach– Fundamental materials engineering and process control
– Optimization of operating conditions
• Accomplishments• Developed and tested alpha, beta systems
• Demonstrated performance against performance targets
• Delivered alpha prototypes for IIT, UTRC for evaluation
MEMS Sensor Development
Task 1a Safety Sensor in Ambient Air
Pd BarrierRare Earth Hydride
Pd BarrierRare Earth Hydride
BarrierBarrier
BarrierBarrier
Microhotptate Platform Microhotptate Platform
Ing-Shin Chen, Phil Chen, F. DiMeo, Jeff Neuner, Andreas Roehrl, Jim Welch
16
MEMS Sensor Development
Task 1a: Safety Sensor in Ambient Air
• Performance Demonstrated to date
– [H2]: 0-12.8%; Operating Temp: ~80oC,
– Response time: < 2 s @ 4%, 1.2s @ 6%
– Environment: 0–75% RH;
50
40
30
20
Sen
so
r R
esp
on
se(A
.U)
50403020100
Time(min)
0.01
0.1
1
10
[H2
] (%
)
50
40
30
20
Sensor Response in 75% Humid Air
Sensor Response in Dry Air H2 Concentration
t90= 35.3 s t90= 12.1 s t90= 12.0 s t90= 7.0 s t90= 5.3 s t90= 2.4 s t90= 1.2 s t90 = 1.8 s
t90 = 37.8 s t90 = 18.5 s t90 = 12.2 s t90 = 6.5 s t90 = 4.8 s t90 = 1.95 s t90 = 1.2 s t90 = 1.2 s
0.1% 0.2% 0.4%
0.8% 1.6% 3.2%
12.8%6.4%
17
• Targets
– [H2]: 1-100%; Temp: 70- 150oC; Response (T90 ):0.1-1 s; Environment: 1-3 atm total pressure, 10-30 mole % water, total H2, 30-75%, CO2, N2
Accuracy: 1-10 % full scale
• Approach– Materials modifications of safety sensor design
– Exploration of different transduction modes.
• Accomplishments• Fabricated new materials combinations
• Investigated new transduction methods
• Delivered alpha prototypes to UTRC
MEMS Sensor Development
Task 1b Pre Stack Monitor
Microhotptate Platform
New Top Layers
Piezo Resistive Transduction
BarrierBarrier
BarrierBarrier
18
MEMS Sensor Development
Task 1b Pre Stack Monitor
• Performance in Dry N2
– 0-4-40% H2
• 37 sec t90 0 - 4%
• 2 sec t90 4 - 40%
– 40 to 10% H2
• 31.8 sec 0-40%
• Performance in 70% RH
– Similar to dry N2
BQ-6-6B
420
400
380
360
340
320
300
280
SB
R(O
hm
s)
6050403020100
Time(min)
40
20
0
[H2
] (%
)
2.780
2.770
2.760HB
R(k
Ohm
s)
600
500
400
300
200
SB
R(O
hm
s)
50403020100
Time(min)
4020
0
[H2
] (%
)
2.94
2.92
2.90
2.88
2.86
2.84
HB
R(k
Oh
ms)
82
80
78
76
74
72
70
68
Re
sis
tan
ce
(Oh
ms)
6040200
Time(min)
40
20
0
[H2
] (%
)2930
2920
2910
2900
Rh
(Oh
ms)
Sensor A Dry
Sensor A in 40% Rh Sensor A Heater Resistance without Humidity Sensor A Heater Resistance with Humidity
H 2 Concentration
19
MEMS Sensor Development
Task 2 H2S Sensor Development
• Targets– Temp: 400oC; Range: 0.05 ppm -0.5 ppm; Response time: < 1 min at
0.05 ppm; Environment: H2,CO, CO2 H2O
• Approach– Ultra thin ( < 50nm) metal film deposition on micro hotplate platform
• Accomplishments– Demonstrated first sensor response to H2S
– 50 nm film responds to H2S• 160°C, 4% H2/N2,
• 20% RH,
• 180 ppm H2S
120
115
110
105
100
95
90
Resis
tance (
ohm
)
2520151050
Time (min)
43210
% H
2
150100
500
H2S
(ppm
)
'% H2' '% H2S' 'Sensor Response'
20
NexTech Materials Sensor DevelopmentMATERIALS
NEXTECH
Mixed Potential
V
Thin
GDC/YSZ
disc
Bianodes
Furnace
Seal
Fuel Cell
IDE Thick
Film
Sensor Platforms
Scott L. Swartz, Ph.D. (P.I.), Chris Holt, Todd G. Lesousky
21
MATERIALS
NEXTECHNexTech Sensor Development
Task 2.1.1 Miniature SOFC Fuel Cell Sensor
• NexTech’s SOFC sensor technology with electrodes engineered to respond to CO show reversible and quantitative response to CO in wet N2/H2.
• Future work will focus on schemes to improve sensitivity for 0-100ppm CO range and testing cross-sensitivity to alternate syngas components
22
MATERIALS
NEXTECH
• Metal oxide based chemi-resistor (not electrochemical sensor) exhibits reversible and quantitative response to H2S
• NexTech is currently evaluating various dopant schemes to reduce thetemperature of operation• Beta prototypes scheduled for early June
NexTech Sensor Development
Task 2.1.2 Hydrogen Sulfide Sensors
23
MATERIALS
NEXTECH
• Metal Oxide films show reversible response to H2S concentrations at 0.5 ppm in syngas (goal of 0.05 – 0.5 ppm).
•Future work will focus on measuring lower sulfur concentrations and cross-sensitivity to individual syngas components.
NexTech Sensor Development
Task 2.1.2 Hydrogen Sulfide Sensors
24
MATERIALS
NEXTECH
NexTech’s metal halide ammonia sensorshows very high sensitivity at lowtemperature
Future work will focus on improving hightemperature sensitivity and measuringcross-sensitivity to other syngascomponents.
Sensor responds reversibly in N2/H2
at 75ºC
NexTech Sensor Development
Task 2.1.3 Ammonia Sensor Response
25
Responses to Previous Year Reviewers’ Comments
• “..difficult to assess technical approach and progress”– Physical sensor evaluation completed
– H2 LEL sensor developed• Best response times <1 s, average ~14s; sensor drift rate < 0.16% / day
– Stack H2 sensor developed• Dynamic response up to 40% H2, H2 levels up to 70%, with humidity
• Fast response (T90<2 sec) with Pd
• New devices shows promise; minor cross sensitivity with CO; Drift <0.2% in 4% H2
– Multiple strategies identified for sensing CO in reducingenvironments; CO sensitivity established in humid environments
– Multiple strategies for sulfur• ATMI- 50 nm Metal Foil shows response to H2S
– NexTech
– H2S/SO2 sensor materials identified
– PPM level detection demonstrated
– Ammonia sensor easily packaged in a chemi-resistor format
Sensors for Automotive PEM-based Fuel Cells Project
Contractor and subcontractor PIs:
Name Affiliation Phone E-mailTom Clark UTPWR 860-727-2287 [email protected]
Brian Knight UTRC 860-610-7293 [email protected]
Frank DiMeo ATMI 203-794-1100 x4279 [email protected]
Joe Stetter IIT 312-567-3443 [email protected]
Scott Swartz NexTech 614-842-6606 x103 [email protected]
MATERIALS
NEXTECH
Team organization
DOE program manager and technical advisor:
Name Affiliation Phone E-mailNancy Garland DOE 202-586-5673 [email protected]
Robert Sutton ANL 630-252-4321 [email protected]