TD Aiken March 31, Developing a Safety Sensor for Fuel Cell Vehicles Thomas Aiken Marketing and Business Development AppliedSensor, Inc. (908)
TD Aiken March 31, AppliedSensor provides gas sensing solutions for safety, quality, comfort and control.
TD Aiken March 31, The Challenge Design and develop a selective safety sensor to detect hydrogen gas leaking within the confines of a hydrogen or fuel cell powered vehicle and do so –within LEL, –to automotive standards, –using high volume manufacturing processes –and, oh by the way, make it cheap
TD Aiken March 31, Why hydrogen but not gasoline sensing? Association of hydrogen and explosions runs deep with the consumer. Gasoline vapor is heavy and will lie low while hydrogen will rise quickly to fill a space. Low molecular weight allows hydrogen leaks to be a constant safety issue.
TD Aiken March 31, Hurdles – Automotive Standards –Detection Range0-4.4% in air –Startup time1 second –Speed of response< 2 seconds –Accuracy+/- 3,000 ppm –Temperature range-40 º to +110 º –Voltage supply variation9-16 volts –Electrical interfaceCAN communication Also…Vibration, shock, EMC - automotive
TD Aiken March 31, Hurdles – Customer Expectations –10,000 modules/year capability –Thousands of units for testing –Security/safety standards –Operating hours –Operate when the vehicle is turned off –ISO certification –Meet ATEX Zone 2 standard
TD Aiken March 31, ISO/TS Project ISO/TS is ISO 9001:2000 with particular requirements for automotive production and service organizations. AppliedSensor to be ISO/TS certified in IEC specifies the general requirements for construction, testing and marking of an electrical apparatus and explosive components intended for use in explosive gas atmospheres
TD Aiken March 31, How does ATEX work - intrinsic safety A security concept is determined The security concept drives requirements on design –Minimum distance between conductors (air, solid) –Maximum temperature –Power limitation –Housing durability, strength, electric insulation and capacitance
TD Aiken March 31, ATEX Zone 2 Zone 0 – flammable vapor exists Zone 1 – flammable vapor likely to exist Zone 2 – an explosive atmosphere consisting of a mixture of air and flammable gas vapor or mist is not likely to occur in normal operation but if it does occur will persist for a period of time.
TD Aiken March 31, Standards in general Significant standarization efforts going on worldwide –ISO/CD Hydrogen detection apparatus (ISO/TC 197 WG 13 ) –EU projects –UL standards, etc.…
TD Aiken March 31, Sensor Development History Early sensing technology relied on field effect principle to detect hydrogen at low levels. Various metals investigated for sensing layer Levels below 1,000 ppm were achieved but this is far below the LEL of 4% in air. Standards and customer requirements dictated an integrated solution. Combination of field effect and thermal conductivity achieved the goal. Wafer sub-suppliers could only be required to meet heater and temperature measurement performance. But gas characterization fell on us and is carried at our risk.
TD Aiken March 31, How we met the challenge - technology 1.Integrated solution –Combine field effect with thermal conductivity –Cross sensitivity – FE principle
TD Aiken March 31, Field Effect Operating Principle SiO 2 p-Si nn I V nn H2H2 H H H - + VV H - + H 2 dissociates H-atoms transport through metal layer H-atoms trapped at metal- insulator interface
TD Aiken March 31, Field Effect Selectivity to H 2 25, 75 and 250 ppm of respective gas
TD Aiken March 31, Thermal conductivity – selectivity to H 2 at 273 K (10 -3 W/mK) Hydrogen (H2) Air Nitrogen (N2) Oxygen (O2) Methane (CH4) Carbondioxide (CO2) Helium (He) Argon (Ar) Ethane (C2H6) Water (H2O)
TD Aiken March 31, How we met the challenge - Production 2. Establish a production process –Class 1,000 clean room –A-B-C sample development (automotive standard) –Design validation tests
TD Aiken March 31, How we met the challenge – Scale up 3. Scale production –Supplier/partners with large volume capabilities –Robust and well established NMOS basic silicon technology –Wafer level clean room production Deposition, annealing, dicing –Automation – chip on board mounting, wire bonding
TD Aiken March 31, How we met the challenge - Performance 4. Testing and Validation –Repeatability (one sensor, time-to-time variation) –Reproducibility (sensor-to-sensor variation) –Accuracy –Selectivity –Etc…..
TD Aiken March 31, Repeatability – same module
TD Aiken March 31, Repeatability - same module
TD Aiken March 31, Reproducibility – different modules
TD Aiken March 31, Reproducibility – different modules
TD Aiken March 31, Response Dynamic 1.2% H 2 pulse
TD Aiken March 31, Accuracy - Module
TD Aiken March 31, Humidity Effect, ~60 º C in 1% H2
TD Aiken March 31, Hydrogen Safety Module HSS-440
TD Aiken March 31, BMW Hydrogen 7
TD Aiken March 31, Locations of the HSS-440 Filling port Engine compartment Hydrogen tank Trunk Cabin
TD Aiken March 31, GENERAL MOTORS Chevrolet Equinox Fuel Cell Chevrolet is committed to bringing you drivable and practical vehicles that decrease our energy dependence and reduce our emissions.
TD Aiken March 31, Mercedes- Benz B-Class F-Cell Launch of the first series-production fuel cell The engine for this innovative vehicle will be a new generation of fuel-cell engine that is much more compact and yet at the same time more powerful and completely practicable for everyday use. Source – Daimler AG
TD Aiken March 31, Ramping up Commercialization Designing for H 2 gas leaks is critical in product development. Ability to detect leaks rapidly is now commercially available for automotive and non- automotive applications. Tough automotive standards have been met and may exceed other application requirements.
TD Aiken March 31, Developing a Safety Sensor for Fuel Cell Vehicles AppliedSensor, Inc. Booth 510