Solar Cell Array Design Handbook

I Solar Cell Arrays.- 1 Array Systems.- Array Concepts.- 1–1. Arrays and Batteries.- 1–2. Arrays, Panels, Parts, and Components.- 1–3. Array Types.- 1–4. The Array as Part of the Power System.- 1–5. The Array as a System.- 1–6. Hybrid Systems 6 Historical Developments.- 1–7. History of Terrestrial Arrays.- 1–8. History of Space Arrays.- 1 –9. The Future of Solar Cell Arrays.- Array Applications.- 1–10. Terrestrial Applications.- 1–11. Space Applications.- 1–12. Power from Space.- Array Systems Performance.- 1–13. Array Ratings.- 1–14. Terrestrial Flat-Plate Arrays.- 1–15. Terrestrial Concentrator Arrays.- 1–16. Space Flat-Hate Arrays.- 1–17. Spinning Space Arrays.- 1–18. Space Concentrator Arrays.- 1–19. Space Array Orbital Performance.- 2 Array Analysis.- Analytical Concepts.- 2–1. The Role of Analysis.- 2–2. Atoms and Electrons.- 2–3. Electric Charge.- 2–4. Conductors.- 2–5. Insulators.- 2–6. Current.- 2–7. Electric Field.- 2–8. Potential and Voltage.- 2–9. Electrical Circuits.- 2–10. Sources and Generators.- 2–11. Current Flow Convection.- 2–12. Resistance and Resistors.- 2–13. Ohm’s Law.- 2–14. Power.- 2–15. Energy.- 2–16. Capacitance and Capacitors.- 2–17. Magnetism.- 2–18. Inductance and Inductors.- 2–19. AC and DC Current.- 2–20. Impedance.- Circuit Analysis.- 2–21. Circuit Modelling.- 2–22. Circuit Simplifications.- 2–23. Circuit Responses.- 2–24. Circuit Equations.- 2–25. Operating Points.- Semiconductors and Solar Cell Models.- 2–26. Quantum Mechanics.- 2–27. Semiconductor Materials.- 2–28. Semiconductor Junctions.- 2–29. Solar Cell Operation.- 2–30. Solar Cell Equation.- 2–31. Solar Cell DC Model.- 2–32. Distributed Parameter Solar Cell Model.- 2–33. Analytical Models for Computer Work.- 2–34. Non-Analytical Computer Models.- 2–35. Selecting the Proper Model.- 2–36. Solar Cell AC Model.- 2–37. Solar Cells in Parallel and Series.- 2–38. Illuminated Arrays.- 2–39. Partially Shadowed Cells in Parallel.- 2–40. Partially Shadowed Cells in Series.- 2–41. Solar Cell Strings with Shunt Diodes.- 2–42. Shadowing Factors.- 2–43. Nonilluminated Array Models.- 2–44. Blocking Diode Models.- 2–45. Reverse-Biased Solar Cells.- 2–46. Power Dissipation in Reverse-Biased Solar Cells.- Array Performance Prediction.- 2–47. Array Output Analysis.- 2–48. Sequence of Shifting I–V Curves.- 2–49. Calculation of Angle of Incidence.- 2–50. Calculation of Effective Solar Intensity.- 2–51. Calculation of Cell and Array I–V Curves.- Shadow Analysis.- 2–52. Shadows 84 Thermal Analysis.- Thermal Analysis.- 2–53. Heat Flow and Temperature.- 2–54. Heat Transfer by Conduction.- 2–55. Heat Transfer by Convection.- 2–56. Heat Transfer by Radiation.- 2–57. Electrical Heat Transfer Analogy.- 2–58. Terrestrial Array Operating Temperatures.- Reliability.- 2–59. Reliability and Failure Rates.- 2–60. Failure Modes and Effects.- 2–61. Reliability Models.- Orbital Analysis.- 2–62. Spacecraft Motion in Orbit.- 2–63. Simplified Orbit Theory.- 2–64. Altitude in Elliptic Orbits.- 2–65. Location in Space.- 2–66. Illumination of the Orbit Plane.- 2–67. The Sun Angle.- 2–68. Solar Eclipses.- 3 Array Design.- Design Concepts.- 3–1. The Design Process.- 3–2. Design Phases.- 3–3. Design Personnel.- 3–4. Uncertainties and Risks.- 3–5. Design Optimization.- 3–6. Design Requirements, Criteria and Interfaces.- 3–7. Policy Constraints.- 3–8. Design Review.- 3–9. Producibility and Cost.- 3–10. Human Engineering.- Photovoltaic System Design.- 3–11. Load Profile Development.- 3–12. Illumination Profile Development.- 3–13. Preliminary Array Sizing—Area Method.- 3–14. Preliminary Array Sizing-Cell Efficiency Method.- 3–15. Preliminary Array Sizing-Cell Power Method.- Detailed Array Design.- 3–16. Detailed Array Sizing.- 3–17. Space Array Configuration Selection.- 3–18. Number of Required Solar Cells.- 3–19. Array Layout.- 3–20. Array Wiring.- 3–21. Hot Spot Design Considerations.- 3–22. Designing for Reliability.- 3–23. High Voltage Design.- Thermal Design.- 3–24. Temperature Control in Space.- 3–25. Temperature Control on Earth.- 3–26. Decreasing Absorptance.- 3–27. Increasing Emittance.- 3–28. Increasing Convection.- 3–29. Improving the Geometry.- 3–30. Minimizing Eclipse Exit Temperatures.- Radiation Shielding Design.- 3–31. Solar Cell Radiation Shielding.- 3–32. Damage-Equivalent Fluence in Orbit.- 3–33. Shielding Thickness Determination.- 3–34. Procedure for 1-MeV Fluence Analysis.- 3–35. Shielding Against Low Energy Protons.- 3–36. Absorbed Dose in Cover and Adhesive.- Electromagnetic Design.- 3–37. Electrostatic Shielding.- 3–38. Magnetic Cleanliness.- 3–39. Minimizing Magnetic Moments.- 3–40. Electrostatic Charging Control.- II Array Building Blocks.- 4 Solar Cells.- Photovoltaics.- 4–1. Solar Cell Devices.- 4–2. Direct Energy Conversion.- 4–3. Discovery of the Photovoltaic Effect.- 4–4. History of Contemporary Silicon Cells.- 4–5. History of Non-Silicon Cells.- Solar Cell Types.- 4–6. Solar Cell Classification.- 4 – 7. Classification According to Application.- 4–8. Classification According to Materials.- 4 –9. Classification According to Construction.- 4–10. Classification According to Optical Features.- 4–11. Contemporary Silicon Solar Cell Types for Space Use.- 4–12. Contemporary Silicon Solar Cells for Terrestrial Use.- Electrical Characteristics.- 4–13. Solar Cell Polarity.- 4–14. Current-Voltage Characteristics.- 4–15. Series Resistance.- 4–16. Shunt Resistance.- 4–17. Energy Conversion Efficiency.- 4–18. Curve and Fill Factors.- 4–19. Effects of Solar Intensity.- 4–20. Reversible Effects of Temperature.- 4–21. Temperature Coefficients.- 4–22. Irreversible Temperature Effects.- 4–23. High-Intensity, High-Temperature Operation.- 4–24. Low-Intensity, Low-Temperature Operation.- 4–25. Reverse Characteristics.- Optical Characteristics.- 4–26. Effects of Optical Characteristics on Cell Efficiency.- 4–27. Spectral Response Defined.- 4–28. Spectral Response of Solar Cells.- Mechanical Characteristics.- 4–29. Solar Cell Sizes and Shapes.- 4–30. Cell Thicknesses.- 4–31. Active Area.- Contacts.- 4–32. Solar Cell Contact Types.- 4–33. Contact Configurations.- 4–34. Contact Strength.- Radiation Effects.- 4–35. Solar Cell Radiation Damage.- 4–36. Damage-Equivalent 1-MeV Fluence.- 4–37. Effects of Base Resistivity.- 4–38. Low-Energy Proton Damage.- 4–39. Radiation Damage Annealing and Output Instabilities.- Practical Considerations.- 4–40. Glassed Cell Output.- 4–41. Distribution of Parameters.- 4–42. Handling Precautions.- 4–43. Storage.- 4–44. Solar Cell Space Flight Experiments.- 4–45. Laboratory Test Data for Space Cells.- 4–46. Radiation Test Data for Space Cells.- 5 Optical Elements.- Functions of Optical Elements.- 5–1. Flat-Plat Optics.- 5–2. Concentrator Optics.- 5–3. Historical Developments.- Optical Energy Transfer.- 5–4. The Optical System.- 5–5. The Air (or Space)-To-Cover Interface.- 5–6. The Cover-To-Cell Interface.- 5–7. Glassing Factors.- 5–8. Angle-of-Incidence Effects.- 5–9. Thermal Control.- Covers for Space Applications.- 5–10. Classification of Covers and Coatings.- 5–11. Cover Materials.- 5–12. Coatings and Filters.- 5–13. Mechanical Characteristics.- 5–14. Conductive Coatings.- 5–15. Cover Adhesives.- 5–16. Integral Organic Covers.- Windows for Terrestrial Applications.- 5–17. Window Construction.- 5–18. Window Requirements.- 5–19. Window Materials.- Sunlight Concentrators.- 5–20. Principles of Sunlight Concentration.- 5–21. Concentrator Types.- 6 Electrical Elements.- Solar Cell Interconnectors.- 6–1. Interconnector Terminology.- 6–2. Interconnector Types.- 6–3. Solar Cell Interconnector Design Requirements.- 6–4. Solar Cell and Interconnector Failure Modes.- 6 – 5. Historical Developments of Solar Cell Interconnectors.- 6–6. Soldered or Welded Joints?.- The Interconnector Design Problem.- 6 – 7. Interconnector Material Selection.- 6–8. Interconnector Electrical Design.- 6 – 9. Minimizing Thermomechanical Stress.- 6–10. Thermomechanical Stress in Rigid Joints.- 6–11. Stresses in Joints Due to External Forces.- 6–12. Changes in Intercell Gap Width.- 6–13. Loop Deformation.- 6–14. Stresses in Interconnector Expansion Loops.- 6–15. Stress-free Interconnector Loops.- 6–16. Stresses in Imbeded Interconnectors and Conductors.- 6–17. Practical Interconnector Design Considerations.- 6–18. Stresses in Flexible Bonded Layers.- Interconnector Fatigue.- 6–19. Static and Dynamic Material Stress.- 6–20. Stress and Strain Loading.- 6–21. Fatigue of Materials.- 6–22. Fatigue Life of Interconnectors.- Diodes.- 6–23. Diode Applications.- 6–24. Blocking Diodes for Energy Conservation.- 6–25. Blocking Diodes for Fault Isolation.- 6–26. Blocking Diode Characteristics.- 6–27. Shunt Diode Use.- 6–28. Shunt Diode Characteristics.- 6–29. Zener Diodes.- Wiring and Cabling.- 6–30. Wires and Cables.- 6–31. Methods of Wiring.- 6–32. Wiring for Terrestrial Arrays.- 6–33. Wiring for Space Arrays.- 6–34. Wire Insulation Properties.- 6–35. Current Carrying Capability.- Terminals and Connectors.- 6–36. Wire Terminations.- 6–37. Connectors and Terminals for Space Arrays.- 6–38. Connectors and Terminals for Terrestrial Use.- 6–39. Termination Design Practices.- 7 Mechanical Elements.- Array Mechanical Characteristics.- 7–1. Array Design Options.- 7–2. Array Mechanical Elements.- Terrestrial Flat Hate Arrays.- 7–3. Flat Plate Modules.- 7–4. Open Frame Supports.- 7–5. Roof Supports.- 7–6. Flat Plate Orientation Mechanisms.- Terrestrial Concentrator Arrays.- 7–7. Linear Concentrator Modules.- 7–8. Axial Concentrator Modules.- 7–9. Mirror Field Systems.- Space Arrays.- 7–10. Space Array Overview.- 7–11. Rigid Honeycomb Panels.- 7–12. Honeycomb Panels With Stiffeners.- 7–13. Flexible Substrates With Rigid Frames.- 7–14. Flexible Fold-Up Blankets.- 7–15. Flexible Roll-Up Blankets.- 7–16. Hybrid Arrays.- 7–17. Other Developments.- Deployment Mechanisms.- 7–18. Deployable Booms.- 7–19. Spring/Actuator Deployment Concepts.- Orientation Drives.- 7–20. Orientation Mechanisms.- 7–21. Stepping Drive Example.- 7–22. Continuous Drive Example.- III Support Data.- 8 Fabrication and Test.- 8–1. Soldering.- 8–2. Welding.- 8–3. Thermocompression Joining.- 8–4. Ultrasonic Joining.- 8–5. Electrical Degradation Due to Joining.- 8–6. Adhesive Bonding.- Assembly Process Control.- 8–7. Metal Joining Control.- 8–8. Nondestructive Testing (NDT).- 8–9. Adhesive Bonding Control.- 8–10. Visual Inspection.- 8–11. Workmanship Criteria.- Photovoltaic Testing.- 8–12. History of Solar Cell-Testing.- 8–13. Standard Solar Cells.- 8–14. light Sources For Solar Cell-Testing.- 8–15. Solar Simulators.- 8–16. Solar Cell Output Measurements.- 8–17. Array Output Measurements.- 8–18. Standard Test Conditions.- 8–19. Effects of Lead and Contact Resistances.- 8–20. Three Types of Solar Cel- V Curves.- 8–21. Measurement of Solar Cell Series Resistance.- 8–22. Dark Forward-Testing.- 8–23. Insulation Resistance and Voltage Breakdown.- Thermo-optical Measurements.- 8–24. Measurement of Spectral Distribution and Spectral Response.- 8–25. Determination of Solar Absorptance.- 8–26. Determination of Hemispherical Emittance.- 8–27. Measurement of Spectral Reflectance.- 8–28. Measurement of Total Reflectance.- Environmental Testing.- 8–29. Particle Radiation Testing.- 8–30. Ultraviolet Radiation-Testing.- 8–31. Far Ultraviolet Testing.- 8–32. Combined Environments-Testing.- 8–33. Temperature Cycling-Testing.- Significance of Test Data.- 8–34. Errors.- 8–35. Uncertainties.- 8–36. Uncertainties in Inspection.- 8–37. Significance of Sample Size.- 9 Environments and Their Effects.- 9–1. The Solar Cell Array Environment.- Solar Energy.- 9–2. The Sun.- 9–3. The Solar Constant.- 9–4. Albedo.- 9–5. Solar Radiation Pressure.- 9–6. Terrestrial Sunshine.- 9–7. Ultraviolet Radiation.- Terrestrial Environments.- 9–8. Temperature-Terrestrial.- 9–9. Humidity.- 9–10. Precipitation.- 9–11. Wind.- 9–12. Sand, Dust, Dirt.- 9–13. Earthquakes.- 9–14. Gravity.- 9–15. The Atmosphere.- 9–16. Atmospheric Electricity.- 9–17. Corrosion.- 9–18. Ozone.- 9–19. Fungi and Bacteria.- 9–20. Salt Spray.- 9–21. Biotic Elements.- 9–22. Vandalism.- Handling and Transportation.- 9–23. Handling and Assembly.- 9–24. Vibration and Acoustic Noise in Transportation.- 9–25. Mechanical Shock in Transportation.- 9–26. Storage.- 9–27. Pressure/Altitude in Transportation.- Launch and Flight of Space Arrays.- 9–28. Dynamic Forces During Launch and Flight.- 9–29. Acceleration.- 9–30. Shock (Mechanical).- 9–31. Vibration.- 9–32. Acoustic Field.- The Space Environment.- 9–33. The Solar System.- 9–34. The Space Vacuum.- 9–35. Meteoroids.- 9–36. Deposits.- 9–37. Gravity in Space.- 9–38. Time in Space.- 9–39. Magnetic Fields.- 9–40. Temperature in Space.- 9–41. Solar Cell Arrays in Orbit.- 9–42. Solar Eclipses.- The Radiation Environment in Space.- 9–43. Radiation Terms.- 9–44. Space Radiation and its Effects.- 9–45. Radiation in Interplanetary Space.- 9–46. Solar Flares.- 9–47. Radiation Near Earth.- 9–48. Radiation At Synchronous Altitude.- 9–49. Geomagnetic Substorms.- 10 Material Properties.- 10–1. Where to Find the Data.- 10–2. Material Properties and the Designer.- General Characteristics.- 10–3. Characteristics of Metals.- 10–4. Characteristics of Non-metals.- 10–5. Density, Mass and Weight.- 10–6. Centroids, Moments of Inertia and Radii of Gyration.- Mechanical Properties.- 10–7. Stress, Strain, and Strength.- 10–8. Stiffness and Bending Stress.- 10–9. Mechanical Properties as Function of Temperature.- 10–10. Elongation and Reduction in Area.- 10–11. Fatigue Life.- 10–12. Mechanical Properties of Elastomers.- 10–13. Outgassing and Weight Loss.- Thermal Properties.- 10–14. Thermal Expansion.- 10–15. Specific Heat and Heat Conductance.- Electromagnetic Properties.- 10–16. Electrical Properties of Conductors.- 10–17. Electrical Properties of Dielectrics.- 10–18. Magnetic Properties.- 10–19. Thermal Emittance 498 Appendices.- Appendices.- Appendix A Mathematics.- Appendix B Insolance Tables.- Appendix C Physical Constants.- Appendix D Conversion Factors and Formulas.- Appendix E 1 MeV Fluence Tables.