Photovoltaic Module Reliability

ISBN-13: 9781119458999 / Angielski / Twarda / 2020 / 264 str.

John H. Wohlgemuth

Spis treści

Acknowledgments xi1 Introduction 11.1 Brief History of PVs 21.2 Types of PV Cells 41.3 Module Packaging - Purpose and Types 81.4 What Does Reliability Mean for PV Modules? 121.5 Preview of the Book 13References 152 Module Failure Modes 172.1 Broken Interconnects 172.2 Broken/Cracked Cells and Snail Trails 212.3 Delamination 242.4 Corrosion of Cell Metallization 262.5 Encapsulant Discoloration 282.6 Failure of Electrical Bonds Particularly Solder Bonds 312.7 Glass Breakage 332.8 Junction Box Problems 352.9 Loss of Elastomeric Properties of Back Sheets 362.10 Reverse Bias Hot Spots 372.11 By-Pass Diodes 392.12 Structural Failures 412.13 Ground Faults and Open Circuits Leading to Arcing 432.14 Potential Induced Degradation 462.15 Thin-Film Specific Defects 482.15.1 Light-Induced Degradation 482.15.2 Inadequate Edge Deletion 492.15.3 Shunts at Laser Scribes and Impurities in Thin Film 492.15.4 Failure of Edge Seals 50References 513 Development of Accelerated Stress Tests 553.1 Thermal Cycling or Change in Temperature 573.2 Damp Heat 583.3 Humidity Freeze 593.4 Ultraviolet (UV) Light Exposure 603.5 Static Mechanical Load 613.6 Cyclic (Dynamic) Mechanical Load 623.7 Reverse Bias Hot Spot Test 633.8 Bypass Diode Thermal Test 633.9 Hail Test 64References 654 Qualification Testing 674.1 JPL Block Buy Program 684.2 Evolution of IEC 61215 Qualification Test Sequence 754.3 IEC 61215 Test Protocol 804.3.1 MQT 01 - Visual Inspection 824.3.2 MQT 02 - Maximum Power Determination 824.3.3 MQT 03 - Insulation Test 824.3.4 MQT 04 - Measurement of Temperature Coefficients 834.3.5 MQT 05 - Measurement of NMOT 834.3.6 MQT 06 - Performance at STC and NMOT 844.3.7 MQT 07 - Performance at Low Irradiance 844.3.8 MQT 08 - Outdoor Exposure Test 854.3.9 MQT 09 - Hot Spot Endurance Test 854.3.10 MQT 10 - UV Preconditioning Test 884.3.11 MQT 11 - Thermal Cycling Test 884.3.12 MQT 12 - Humidity-Freeze Test 894.3.13 MQT 13 - Damp-Heat Test 894.3.14 MQT 14 - Robustness of Termination 904.3.15 MQT 15 - Wet Leakage Current Test 914.3.16 MQT 16 - Static Mechanical Load Test 914.3.17 MQT 17 - Hail Test 924.3.18 MQT 18 - Bypass Diode Test 924.3.19 MQT 19 - Stabilization 944.4 How Qualification Tests have been Critical to Improving the Reliability and Durability of PV Modules 954.5 Limitations of the Qualification Tests 974.6 PV Module Safety Certification 984.6.1 Construction Requirements: IEC 61730-1 994.6.1.1 Components 994.6.1.2 Mechanical and Electromechanical Connections 1014.6.1.3 Materials 1034.6.1.4 Protection Against Electric Shock 1054.6.2 Requirements of Testing IEC 61730-2 1104.6.2.1 MST 01 - Visual Inspection 1134.6.2.2 MST 02 - Performance at STC 1134.6.2.3 MST 03 - Maximum Power Determination 1144.6.2.4 MST 04 - Insulation Thickness Test 1144.6.2.5 MST 05 - Durability of Markings Test 1144.6.2.6 MST 06 - Sharp Edge Test 1144.6.2.7 MST 07 - Bypass Diode Functionality Test 1144.6.2.8 MST 11 - Accessibility Test 1144.6.2.9 MST 12 - Cut Susceptibility Test 1154.6.2.10 MST 13 - Continuity Test of Equipotential Bonding 1154.6.2.11 MST 14 - Impulse Voltage Test 1154.6.2.12 MST 16 - Insulation Test 1164.6.2.13 MST 17 - Wet Leakage Current Test 1164.6.2.14 MST 21 - Temperature Test 1164.6.2.15 MST 22 - Hot Spot Endurance Test 1174.6.2.16 MST 24 - Ignitability Test 1174.6.2.17 MST 25 - Bypass Diode Thermal Test 1174.6.2.18 MST 26 - Reverse Current Overload Test 1174.6.2.19 MST 32 - Mechanical Breakage Test 1184.6.2.20 MST 33 - Screw Connections Test - Test for General Screw Connections MST 33a 1184.6.2.21 MST 33 - Screw Connections Test - Test for Locking Screws MST 33b 1194.6.2.22 MST 34 - Static Mechanical Load Test 1194.6.2.23 MST 35 - Peel Test 1194.6.2.24 MST 36 - Lap Shear Strength Test 1204.6.2.25 MST 37 - Materials Creep Test 1214.6.2.26 MST 42 - Robustness of Termination Test 1214.6.2.27 MST 51 - Thermal Cycling Test 1214.6.2.28 MST 52 - Humidity Freeze Test 1214.6.2.29 MST 53 - Damp Heat Test 1214.6.2.30 MST 54 - UV Test 1224.6.2.31 MST 55 - Cold Conditioning 1224.6.2.32 MST 56 - Dry Heat Conditioning 1224.6.2.33 Recommendations for Testing of PV Modules from Production 122References 1235 Failure Analysis Tools 1275.1 PV Performance - Analysis of Light I-V Curves 1275.2 Performance as a Function of Irradiance 1325.3 Dark I-V Curves 1365.4 Visual Inspection 1375.5 Infrared (IR) Inspection 1435.6 Electroluminescence (EL) 1455.7 Adhesion of Layers, Boxes, Frames, etc. 149References 1496 Using Quality Management Systems to Manufacture PV Modules 1516.1 Quality Management Systems 1516.2 Using ISO 9000 and IEC 61215 1536.3 Why just Using IEC 61215 and ISO 9000 is No Longer Considered Adequate? 1546.4 Customer Defined "Do It Yourself" Quality Management and Qualification Systems (IEC 61215 on Steroids) 1566.5 Problems with the "Do It Yourself" System 157References 1637 The PVQAT Effort 1657.1 Task Group 1: PV QA Guidelines for Module Manufacturing 1677.2 Task Group 2: Testing for Thermal and Mechanical Fatigue 1697.3 Task Group 3: Testing for Humidity, Temperature and Voltage 1757.3.1 Corrosion 1767.3.2 Delamination 1777.3.3 PID 1797.3.4 Delamination Due to Voltage Stress 1817.4 Task Group 4: Testing for Diodes, Shading and Reverse Bias 1827.5 Task Group 5: Testing for UV, Temperature and Humidity 1867.6 Task Group 6: Communications of Rating Information 1897.7 Task Group 7: Testing for Snow and Wind Load 1897.8 Task Group 8: Testing for Thin-Film Modules 1907.9 Task Group 9: Testing for Concentrator Photovoltaic (CPV) 1907.10 Task Group 10: Testing for Connectors 1907.11 Task Group 11: QA for PV Systems 1917.12 Task Group 12: Soiling and Dust 1917.13 Task Group 13: Cells 192References 1928 Conformity Assessment and IECRE 1958.1 Module Conformity Assessment - PowerMark, IECQ, PVGAP, and IECEE 1958.1.1 PV-1: "Criteria for a Model Quality System for Laboratories Engaged in Testing PV Modules" 1968.1.2 PV-2: Model for a Third-Party Certification and Labeling Program for PV Modules 1978.1.3 PV-3: Testing Requirements for a Certification and Labeling Program for PV Modules 1978.1.4 PV-4: Operational Procedures Manual for the Certification Body of the PV Module Certification Program 1978.1.5 PV-5: Application and Certification Procedures for the PV Module Certification Program 1988.2 IECRE - Conformity Assessment for PV Systems 201References 2069 Predicting PV Module Service Life 2099.1 Determining Acceleration Factors 2109.1.1 Thermal Cycling 2129.1.2 Discoloration of the Encapsulant 2139.1.3 PET Hydrolysis 2139.2 Impact of Design and Manufacturing on Failure or Degradation Rates for PV Modules 2159.3 Impact of Location and Type of Mounting on Failure or Degradation Rates for PV Modules 2169.4 Extended Stress Testing of PV Modules 2219.5 Setting Up a True Service Life Prediction Program 226References 22710 What does the Future Hold for PV and a Brief Summary 22910.1 Current Work on Updating Standards 22910.1.1 Second Edition of IEC 61215 Series 22910.1.2 Amendment 1 to Second Edition of IEC 61730-1 and IEC 61730-1 23410.1.3 IEC TS 63126 - Guidelines for Qualifying PV Modules, Components and Materials for Operation at High Temperatures 23410.2 Looking to the Future 23710.2.1 Degradation Rates 23710.2.2 Module Lifetime 23810.3 Brief Summary 23910.3.1 Personal Reflections 240References 240Index 243

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JOHN H. WOHLGEMUTH, PHD, is the Executive Director of PowerMark Corporation, VA, USA, and serves as the Technical Advisor to IEC Technical Committee 82 on Photovoltaics. Dr. Wohlgemuth has worked in PV for more than 40 years at Solarex, BP Solar and NREL. His PV experience includes cell processing and modeling, Si casting, module materials and reliability, and PV performance and standards. Dr. Wohlgemuth has been an active member of working group 2 (WG2), the module working group within IEC TC-82 since 1986.