FCV Learning Demonst

First-Generation Vehicle Re

Factors Affecting 

Fuel Cell Degradati

Keith Wipke, Sam Sprik, Jennifer Kurtz, Ho

John Garbak

2

Fuel Cell Seminar, San Antonio, TX

October 17, 2007

1NREL, 2US Dept. of Energy

This presentation does not contain any proprietary or confid

NREL/PR-560-42199
Outline

• Objectives and Partners• Methodology and Data Analysis• How to Access Full Results• Highlighted Results

– Fuel Cell Efficiency and Power Po– FC Voltage Degradation and Fact– Driving and Refueling Behaviors
Fuel Cell Vehicle Learning Dem

Project Objectives and Ta

• Objectives

– Validate H

2 FC Vehicles and Infrastruct

– Identify Current Status and Evolution of 

• Assess Progress Toward Technology Read• Provide Feedback to H

2 Research and Dev

Performance Measure 2009* 2015**

Fuel Cell Stack Durability 2000 hours 5000 hours

Vehicle Range 250+ miles 300+ milesHydrogen Cost at Station $3/gge $2-3/gge

* To verify progress toward 2015 targets** Subsequent projects to validate 2015 targets

Key Targets

Hydrogen refueli
Vehicle Status: All of First Generati

Deployed, 2nd Generation Initial Introduc

On-Board Hydrogen Storage Methods

-

102030405060708090

2005Q2 2005Q3 2005Q4 2006Q1 2006Q2 2006Q3 2006Q4 2007Q1 2007Q2

# of Vehicles (All Teams)

Liquid H210,000 psi tanks5,000 psi tanks

Created Aug-28-2007 9:29PM

77
Infrastructure Hydrogen Production Methods 

012345

Delivered

Compressed H2

Natural Gas On-site

Reforming

Electrolysis Delivered Liquid H2

Production Technology

# of Stations

Created Aug-23-07

~2/3 of the Project’s Infrastructure to 

Has Been Installed – 4 Types (e

Mobile Refueler

San Francisco, CA

DTE/BP Po

Southfi

Autothermal Reformer 

Chino, CA

Total: 14

4 stations added in 

last six months

Online Stations

02468

10121416

2005 Q2 2005 Q3 2005 Q4 2006 Q1 2006 Q2 2006 Q3 2006 Q4 2007 Q1 2007 Q2

Reporting Period

Number of Stations

Created Aug-12-07
Refueling Stations from All Four T

Vehicle/Infrastructure Performance in V

Northern CaliforniaSouthern California 

Sep-13-2007

SE Michigan 
>2 Years of Data Analyzed 

Current Status of Data Reporting to the Hydrogen Secur

Through August 2007:

>149,000 individual vehicle trips

40 GB of on-road data

Composite 

Data 

Products

Detailed 

Data 

Products

NREL

HSDC
NREL Web Page Provides Dire

to All Composite Data Pro

http://www.nrel.gov/hydrog
0-5% Pwr 5-10% Pwr 10-20% Pwr 20-40% Pwr 40-60% Pwr 60-80% Pwr 80-

05

101520253035404550

% Time at Power Level

% Fuel Cell Power (Gross) of Max

On-Road % Time at Power Levels: DOE Fleet

Created: Sep-10-07 4:31 PM

On-Road FC Operating Power Points: Dyno 

High Efficiency at 1⁄4 Power Point – Key to O

Ste

at 

~85% time spent at <40% power
0 500 1

100120140160180200220240

ST

Predicted Voltage at 300A

Voltage vs. Opera

938 hrs

ThrNom

13 mV

0 500 1

Created: 28-Feb-2006

Method for Projecting Time to 10% F

Voltage Degradation

Technique makes performance 

projection based on all available 

FC data; Includes reporting 

confidence in results 0 500 

100120140160180200220240

S

Predicted Voltage at 300A

Voltage vs. O

ThNo

1

0 500 

Note: 10% is an R&D metric for FC stack 

degradation. It does not necessarily 

indicate an end-of-life condition. OEMs 

may use other values or indicators.
0

200400600800

10001200140016001800200022002400

2006 Target2009 Target

Actual Operating Hours Accumulated To-Date Projected Hou

Max Hrs Accumulated (1)(2) Avg Hrs Accumulated (1)(3) Projection to 

Time (Hours)

DOE Learning Demonstration Fuel Cell Stack Durabi

Based on Data Through 2007 Q2

Created: Aug-23-07 10:42 AM

(1) Range bars created using one data point for each OEM.(2) Range (highest and lowest) of the maximum operating hours accumulated to-date of any OEM's individual stack (3) Range (highest and lowest) of the average operating hours accumulated to-date of all stacks in each OEM's flee(4) Projection using on-road data -- degradation calculated at high stack current. This criterion is used for assessing  may differ from OEM's end-of-life criterion, and does not address "catastrophic" failure modes, such as membra(5) Using one nominal projection per OEM: "Max Projection" = highest nominal projection, "Avg Projection" = averag

 The shaded green bar represents an engineering judgment of the uncertainty due to data and methodology limit as additional data are accumulated.

As More Gen 1 Data Is Accumu

Teams Are Demonstrating Long 

(DOE Milestone)

Accumulation of FC stack operating hours 

continues to grow, and we’re approaching the first 

stack reaching 1000 hours of real-world operation
Primary Factors Affecting Learning Demo Fleet Fu

FC Diversity (Among Teams) Limits Drawing Str

~29% Decay rate variance explained by a combination of the data variables below1

C

De

Starts per hour (+)

Hig

Power levels (high & average) (+)

Trip length (-)Time between trips (+)

~10% Decay rate variance explained by a combination of the data variables below1

C

De

Idle time (+)

Hig

Power levels (low) (+)

1. Findings based on a Learning Demonstration Fleet, Partial Least Squares (PLS) regression model. A

variance explained by the model.

2. As part of the variable combination, a (+) indicates a directional relation to high decay rate and a (-) ind

Created: Aug-31-07 9:00 AM
0 5 10 15 20 

05

101520253035404550

% Trips within a mileage range

Trip Length (miles)

Trip Length (in miles): DOE Fleet

Created: Sep-10-07 4:31 PM 2001 NHTS Data; Only 

Source: http://nhts.orn

Learning Demo FCVs Tend to Take M

<2 Miles Than Compared to Natio

Large number of short driving trips 

could cause life of Learning Demo 

Fuel Cells to be shorter than if 

driven by average consumer

Further investigation necessary before 

strong conclusions can be drawn about 

trip length affects on FC life
Easier (but Still Difficult!) to Pull Out Domin

Factors When Looking at One Team’s St

Team 4

Team 3 T

T

Starts per

Hour

Trip 

Length

Time Between 

Trips

Id

Tim

Ambient Temperature

Power Levels

1. Results are from partial least squares (PLS) regression analysis of each team’s fleet of ve

2. First two collections of factors cover ~61%-76% of decay rate variance

Created: Aug-31-07 9:00 AM
Most of Infrastructure Safety Re

Non-Events (and Most of Those, A

0 10 20 30 40 50 60 70 

Non-Event

Near Miss

Incident

Number of Reports

Severity

Total Infrastructure Safety Reports by Severity

and Report Type through 2007 Q2

Alarms OnlyAutomatic SysteElectrical IssueEquipment MalfuH2 Release - MinH2 Release - SigNon-H2 ReleaseSystem Trouble, 

Created: Sep-06-07 7:36 AM

No new incidents or near 

misses in last 9 months
0 10 20 30 40 50 60 70 

Non-Event

Near Miss

Incident

Number of Reports

Severity

Primary Factors of Infrastructure Safety Reports

Through 2007 Q2

Calibration/Settings/ Software ControlsDesign FlawEnvironment (Weather, Power Disruption, OtherInadequate/ Non-working EquipmentMaintenance RequiredMischief, Vandalism, SabotageNot Yet DeterminedOperator/Personnel Error

Created: Sep-06-07 7:36 AM

No Single Dominant Factor Tri

Refueling Station Safety R
0 2 4 6 8 10 12 14 16 18 20 0

100200300400500600700800900

1000

Time (min)

Number of Fueling Events

Histogram of Fueling Times

All Light Duty Through 2007Q2

Average = 3.66

 % <5 = 85

Created: Aug-23-07 1:29 PM

Actual Vehicle Refueling Times and A

>6,300 Events: Measured by Stations 

>

Average time: 

85% of refueling eve

0 0.5 1 1.5 2 2.5 

0

50

100150200250

Amount Fu

Number of Fueling Events

Histogram of FuAll Light Duty Th

Average = 2.21

Created: Aug-23-07 1:29 PM

Average amount: 2.21 kg

Includes Comm. and NonComm. Fills
0 0.2 0.4 0.6 0.8 1 1.2 1.4 

0

50

100150200250300350400450500

Avg Fuel Rate (kg/min)

Number of Fueling Events

Histogram of Fueling Rates

All Light Duty Through 2007Q2

5 minute fill of5 kg at 350 bar

3 minute fill o5 kg at 350 b

Average = 0.76

 % >1 = 23

2006 Tech V2010 MYPP 

Created: Aug-23-07 1:29 PM

Actual Vehicle Refueling Rates fr

Events: Measured by Stations or 

Average rate: 0.76 kg/min

23% of refueling events exceeded 1 kg/min

Includes Comm. and NonComm. Fills
Communication H2 Fills Achieving H

than Non-Communication, But No

0 0.2 0.4 0.6 0.8 1 1.2 1.4 

0

0.10.20.30.40.50.60.7

Avg Fuel Rate (kg/min)

Number of Events (Normalized)

Histogram of Fueling Rates

Comm vs Non-Comm Fills - All Light Duty Through 200

5 minute fill of5 kg at 350 bar

3 minute fill o5 kg at 350 b

CommNon-Comm2006 Tech V2010 MYPP 

Created: Aug-22-07 5:46 PM
Tank Levels: DOE Fleet

14%

E 

Created: Sep-10-07 3:14 PM

1. Some refueling events not recorded/detected due to data noise or inco

Median Tank Level = 40% at Fill

2. The outer arc is set at 20% total refuelings.3. If tank level at fill was not available, a complete fill up was assumed.

Large Spread in H2 Tank Level 

Peak at ~1/4 Full, Median at 
Refueling by Time of Day: DOE Fleet

9%

3

12

9

6

Created: Sep-10-07 3:14 PM

% of fills b/t 6 AM & 6 PM: 86.0% 

1. Fills between 6 AM & 6 PM2. The outer arc is set at 12 % total Fill.3. Some events not recorded/detected due to data noise or incompleteness.

AM PM

Refueling by Time of Day; Relati

Refueling Infrastructure Demand 

Created

% 

1. Fills 2. The 3. Som
Driving Start Time - Day: DOE Fleet

8%

3

12

9

6

2001 NHTS Data; Only Car, Truck, Van, & SUV trips included in data set shown here

Created: Sep-10-07 3:11 PM

% of driving trips b/t 6 AM & 6 PM: 80.0% 

1. Driving trips between 6 AM & 6 PM2. The outer arc is set at 10 % total Driving.3. Some events not recorded/detected due to data noise or incompleteness.

AM PM

% of NHTS trips b/t 6 AM & 6 PM: 80.1%

Source: http://nhts.ornl.gov/download.shtml#2001, ASCII.csv

Driving Trip Start Time – Day

Matches National Statistics Exce

Created

% 

1. Driv2. The 3. Som

% 
Summary

• More than half of project completed

– 77 vehicles and 14 stations deployed– 800,000 miles traveled, 30,000 kg H2 produced 

– 114,000 individual vehicle trips analyzed– Project to continue through 2009

• Examination of Factors Affecting FC Degra

– More difficult to identify trends across all 4 team

team individually

– NREL will collaborate with each team to investi

• Total of 41 composite data products publis

– This presentation only covered some of the new– Web site allows direct web access to all CDPs

• Roll-out of 2nd generation vehicles is begin

– First public 700 bar station opened in U.S. – Irv– Additional 700 bar refueling being installed in n
Questions and Discus

Project Contact: Keith Wipke, National Rene

303.275.4451 keith_wipke@

All public Learning Demo papers and presentations are a

online at http://www.nrel.gov/hydrogen/proj_tech_validat