Table of Contents

Cover

Title Page

About the Author

Preface

Chapter 1: Basic Physics of Solar Cells

1.1 Development of Solar Cells
1.2 Solar Radiation and Air Mass
1.3 Basics of Semiconductors
1.4 Light Absorption of Semiconductor Materials
1.5 P-N Junctions and PV Effect of Solar Cells
1.6 Solar Cells of Heterojunctions

Chapter 2: Materials of Solar Cells

2.1 Low-Cost Solar-Grade Polycrystalline Silicon
2.2 Casting Polycrystalline Silicon
2.3 CZ Monocrystalline Silicon
2.4 Nature of a-Si/µC-Si Thin Film
2.5 Preparation Methods of a-Si/µC-Si Film
2.6 Compound Semiconductor Materials
2.7 Analysis on Impurities in Semiconductor Materials

Chapter 3: Preparation Methods of Crystalline Silicon Solar Cells

3.1 Preparation Process Flow of CSSCs
3.2 Performance Detection and Sorting of Raw Silicon Wafer
3.3 Silicon Wafer Surface Cleaning and Texturing
3.4 Junction Preparation by Diffusion
3.5 Plasma Corrosion and Laser Edging Isolation
3.6 Removal of PSG
3.7 Preparation of Anti-Reflection Coating by PECVD and PVD Methods
3.8 Preparation of Top/Bottom Electrodes (Surface Metallisation)
3.9 Cell Testing and Sorting
3.10 Automation of CSSC Production Techniques
3.11 Parameter Measurement in CSSC Production Process
3.12 Product Quality Control and Cost Analysis for Solar Cell Production Lines

Chapter 4: Preparation Methods of Thin Film Silicon Solar Cells

4.1 Advantages and Prospects of TFSSCs
4.2 Structures and Power Generation Principles of TFSSCs
4.3 Preparation Techniques of TFSSCs
4.4 Main Production Equipment for TFSSCs
4.5 Discussion on Some Issues Concerning TFSSC Preparation
4.6 Adjustment of TFSSC Energy Band Structure
4.7 Physical Principle of PECVD and Deposition of Silicon Thin Film
4.8 Physical Sputtering Principles and TCO and Back Metal Preparation System

Chapter 5: High-Efficiency Silicon Solar Cells and Non-Silicon-Based New Solar Cells

5.1 High-Efficiency Crystalline Silicon Solar Cells (CSSCs)
5.2 Production Techniques of HIT High-Efficiency Solar Cells
5.3 Compound Semiconductor Solar Cells
5.4 Next-Generation Solar Cells

Chapter 6: Modules and Arrays of Solar Cells

6.1 General
6.2 Module Packaging Materials
6.3 Module Packaging Techniques
6.4 Module Packaging System
6.5 Reliability of Solar Cell Modules and Inspection After Packaging
6.6 Efficiency, Common Specifications and Market Development Trend of Solar Cell Modules
6.7 Solar Cell Arrays

Chapter 7: PV Systems and Grid-Connected Technologies

7.1 Overview on the PV System
7.2 Energy Storage Batteries
7.3 Core of the Inverter—Power-Switching Devices
7.4 Inverters
7.5 Controllers: Module Power Optimisation and Intelligent Monitoring
7.6 Applications of PV Systems
7.7 BIPV and Distributed PV Stations
7.8 Grid-Connected PV Systems and Intelligent Grids
7.9 Codes and Test Verifications of the PV System

Bibliography

Index

End User License Agreement

List of Illustrations

Chapter 1: Basic Physics of Solar Cells

Figure 1.1 Timescale for depletion of conventional fossil energy resources in China and across the world (based on the proved reserves and current consumption rate).
Figure 1.2 Forecast of world energy consumption structure in the twenty-first century.
Figure 1.3 China's PV parity price development roadmap, issued by China's relevant department.
Figure 1.4 Air mass diagramme.
Figure 1.5 Solar radiation wavelength distribution (AM0 and AM1.5).
Figure 1.6 Change in the solar radiation intensity onto the earth's surface with the wavelength.
Figure 1.7 Variation of solar spectral intensity of some region from 8:00 a.m. to 4:00 p.m.
Figure 1.8 Electron communisation of the isolated atom and the atom in a crystalline.
Figure 1.9 Energy band image of insulator, conductor and semiconductor.
Figure 1.10 Atomic structure and energy band image of doped silicon (a) N-type semiconductor; (b) P-type semiconductor.
Figure 1.11 Electron distribution function f(E) in the semiconductor material, and its relationship with temperature.
Figure 1.12 Three types of carrier recombination process: (a) direct recombination; (b) recombination via the recombination centre; and (c) surface recombination.
Figure 1.13 Light reflection, transmittance and absorption when the solar rays radiate vertically on the semiconductor.
Figure 1.14 Relationship of the absoprtion coefficient of some key semiconductor materials and the wavelength.
Figure 1.15 Comparisons on energy band structure of crystalline silicon and GaAs.
Figure 1.16 Relationship between available solar energy and the thickness of Siand GaAs materials and at AM0 and AM1.0.
Figure 1.17 Maximum solar cell conversion efficiency of materials in different forbidden band gap.
Figure 1.18 Bending of P-N junction bands and formation of built-in field.
Figure 1.19 P-N junction and its band diagramme at a forward bias.
Figure 1.20 V-I characteristic curve of the P-N junction.
Figure 1.21 Band structure change of a P-N junction with or without solar radiation: (a) band diagramme of P-N junction before solar ray radiation; (b) band diagramme of P-N junction after solar ray radiation.
Figure 1.22 Generation principle diagramme of crystalline silicon solar cells.
Figure 1.23 Electrical properties of solar cells in solar rays: (a) V-I characteristics of the solar cell in the solar ray; (b) both the short-circuit current and the open-circuit current rise with light intensity growth.
Figure 1.24 Load V-I characteristic curve.
Figure 1.25 Light/dark characteristic curves of the solar cell. (The shadow area corresponds to the output power of the solar cell.)
Figure 1.26 Influence of series resistance on the V-I curve of the solar cell.
Figure 1.27 Temperature characteristics of the crystalline silicon solar cell.
Figure 1.28 Influence of the recombination speed of the carriers of the cell back surface on the solar cell performance.
Figure 1.29 Outline and basic structure of silicon solar cells.
Figure 1.30 Spectral response of a monocrystalline silicon solar cell.
Figure 1.31 Energy losses of traditional solar cells: (1) Grid heat vibration losses; (2) Voltage losses of P-N junctions; (3) Voltage losses of Ohm junction contact; (4) Recombination losses.
Figure 1.32 Equilibrium energy band diagramme before/after the abrupt P-N heterojunction is formed: (a) before contact (b) after contact.
Figure 1.33 Energy band diagramme of the heterojunction solar cell (a) in the solar ray; (b) without solar ray.

Chapter 2: Materials of Solar Cells

Figure 2.1 Sources of solar-grade polycrystalline silicon in 2002.
Figure 2.2 Industrial chain of the solar cell silicon.
Figure 2.3 Influence of impurity element contents on solar cell conversion efficiency.
Figure 2.4 Variation relationship of the free energy of formation of oxide with temperature, including Na₂O, SiO₂ and B₂O₃ and so on.
Figure 2.5 Ternary phase diagramme of Na₂O-CaO-SiO₂.
Figure 2.6 FBR furnace of Wacker.
Figure 2.7 Flow chart of SiCl₄ zinc reduction method.
Figure 2.8 VLD experimental equipment of Tokuyama.
Figure 2.9 Hydrogenation flow chart of the by-product SiCl₄ of improved Siemens method.
Figure 2.10 Standard free energy-temperature variation curve of hydrogenation reaction.
Figure 2.11 Process comparisons of HEX and Bridgman methods.
Figure 2.12 Melting furnace and ingot casting diagramme for polycrystalline silicon preparation by directional solidification after melting.
Figure 2.13 Quartz crucible and polycrystalline silicon ingot used in direct melting and directional solidification method.
Figure 2.14 Longitudinal section of casting crystalline silicon ingot columns growing in the heat field control conditions.
Figure 2.15 Line-cutting diagramme of casting crystalline silicon ingots.
Figure 2.16 Distribution of the minority carrier lifetime in different sections of the ingot.
Figure 2.17 Distribution of interstitial oxygen concentration in ingot growing direction.
Figure 2.18 Si-C phase diagramme in silicon-enriched zone.
Figure 2.19 Distribution of interstitial Fe concentration along the height direction of silicon ingots.
Figure 2.20 When the silicon crystal grain grows in a direction vertical to the P-N junction, the crystal boundary has no influence over the movement of the photo-generated carriers.
Figure 2.21 Longitudinal section of pseudo-single crystals.
Figure 2.22 Heat transfer of grain growth by CZ method—isotherm $c02-math-033$ heat flow direction.
Figure 2.23 Natural convection in the crucible.
Figure 2.24 Heat flow direction diagramme in the crystal prepared by CZ method.
Figure 2.25 Impurity concentration distributions near solid-liquid.
Figure 2.26 TDR-105 silicon monocrystalline furnace for solar cells.
Figure 2.27 Energy band diagramme of a-Si.
Figure 2.28 Diagramme of µC-Si incubated from a-Si and grain growth.
Figure 2.29 Solar cells with stacked layer of a-Si/µC-Si to extend the absorption light wavelength range.
Figure 2.30 Chlorosilane disproportionation plant.
Figure 2.31 HWCVD reaction chamber diagramme.
Figure 2.32 Longitudinal concentration distribution of oxygen in silicon by SIMS, EAG.
Figure 2.33 Detection principles of carbon/oxygen content in silicon wafer infrared spectroscopy.

Chapter 3: Preparation Methods of Crystalline Silicon Solar Cells

Figure 3.1 Structural diagramme of crystalline silicon solar cells.
Figure 3.2 Relations of junction depth, cell efficiency and doping concentration of N zone.
Figure 3.3 Influence of carrier surface on quantum efficiency of PN junction solar cell (a) back surface; (b) irradiating surface,
Figure 3.4 Traditional process flows of CSSCs.
Figure 3.5 Principle diagramme of hot probe method to measure the silicon wafer conduction type.
Figure 3.6 Principle diagramme of four-probe method for resistance measurement.
Figure 3.7 Influence of carrier lifetime in base zone on cell parameters.
Figure 3.8 Measurement circuit diagramme of the minority carrier lifetime by microwave photoconduction attenuation method.
Figure 3.9 Silicon wafer thickness tester of MTI, USA.
Figure 3.10 Outline of FORTRIX silicon wafer tester (4800 mm × 1900 mm × 1900 mm).
Figure 3.11 Sorting line of FORTRIX silicon wafer tester.
Figure 3.12 Scan electron microscope of monocrystalline texture structure.
Figure 3.13 Scan electron microscope picture of casting polycrystalline surface texture structure.
Figure 3.14 Flow chart of typical bath-type chemical texturing for monocrystalline silicon wafer.
Figure 3.15 Conveyor chain-type cleaning and texturing equipment, RENA.
Figure 3.16 Silicon wafer surface texture after laser texturing.
Figure 3.17 RIE system, IPS.
Figure 3.18 Silicon wafer surface and anti-reflection reduction after RIE process is used.
Figure 3.19 POCl₃ closed-tube diffusion furnace.
Figure 3.20 Temperature distribution curve of diffusion furnace.
Figure 3.21 Phosphorus doping machine, SCHMID.
Figure 3.22 Conveyor and internal structure of BTU chain-type diffusion furnace.
Figure 3.23 Measurement of diffusion layer thickness of solar cells by SIMS method.
Figure 3.24 SRP diagramme.
Figure 3.25 Mounting and equipment of plasma edging isolation.
Figure 3.26 Diagram of plasma etcher.
Figure 3.27 Diagramme of plasma etching system.
Figure 3.28 Plasma etching terminal detection.
Figure 3.29 Diagramme of laser edging isolation processing.
Figure 3.30 Diagramme of process procedure for PSG removal.
Figure 3.31 Removing the surrounding diffusion layer while removing the PSG back junction by chemical corrosion methods (Edge Isolation Machine HYB-4000 T, Shenzhen Hongyibao Automation Equipment Co., Ltd.).
Figure 3.32 Refractive-index of several common anti-reflection coatings and crystalline silicon as a function of wavelength.
Figure 3.33 Coating formation in PECVD vacuum chamber.
Figure 3.34 Diagramme of PECVD system.
Figure 3.35 Diagramme of tubular direct PECVD system (left) and chain-type indirect PECVD system (right).
Figure 3.36 Tubular direct PECVD system and graphite rack boat.
Figure 3.37 Plate-type direct PECVD system.
Figure 3.38 Tiled indirect PECVD system and graphite rack plate, ROTH-RAU.
Figure 3.39 Diagramme of silicon nitride physical sputtering.
Figure 3.40 Silicon target used by physical sputtering method.
Figure 3.41 Control of silicon nitride coating thickness by regulating gas flow.
Figure 3.42 Astro-SiN50 system and PVD process chamber.
Figure 3.43 Light reflection of thin film coating.
Figure 3.44 Basic principle of the ellipsometer.
Figure 3.45 Process procedures of top/bottom electrodes (from right to left).
Figure 3.46 Preparation, laser edging isolation, cell testing and sorting production lines of BACCINI for top/bottom electrodes.
Figure 3.47 Temperature curve of a typical sintering furnace.
Figure 3.48 Outline, inner furnace and conveyor of the sintering furnace, DESPATCH.
Figure 3.49 On-line monitoring equipment of solar cells.
Figure 3.50 Production flow chart of typical tubular solar cells.
Figure 3.51 Layout of typical tubular solar cell workshop and equipment.
Figure 3.52 Production flow chart of typical cascading-type) solar cells.
Figure 3.53 Production flow chart of typical cascading-type CSSC production lines.
Figure 3.54 Robots of the solar cell production line, MANZ and SCHMID.
Figure 3.55 Spectrum of the pulse xenon lamp, close to the sunlight (a) AM1.5 solar spectrum; (b) Spectrum of the pulse xenon lamp, close to the AM1.5 sunlight.
Figure 3.56 Basic structure of solar simulator and measurement system.
Figure 3.57 V-I characteristics of solar cells at various light intensities.
Figure 3.58 Four-end measurement method for V-I characteristics of solar cells.
Figure 3.59 Diagramme of cell spectral response measured by a monochromator.

Chapter 4: Preparation Methods of Thin Film Silicon Solar Cells

Figure 4.1 Structural diagramme of a-Si:H and a-Si:H/μC-Si stacked solar cells.
Figure 4.2 Typical structure of a-Si:H/μC-Si stacked TFSCs.
Figure 4.3 Production process of a-Si:H/μC-Si stacked TFSCs.
Figure 4.4 Energy band diagramme: (a) P-I-N single-junction solar cells; (b) P-I-N/P-I-N double-junction stacked cells.
Figure 4.5 Comparisons between the a-Si:H/μC-Si stacked solar cell and the a-Si single-junction TFSC on absorption spectrum.
Figure 4.6 Series connections of TFSC monolithic circuit by three laser scribings.
Figure 4.7 Series connections of monolithic circuit for TFSSCs: (a). single-junction cell; (b). multi-junction cell; (c). cell integration.
Figure 4.8 Packaging process chart of TFSC modules.
Figure 4.9 Picture of TFSSCs.
Figure 4.10 Production flow diagramme of TFSSCs.
Figure 4.11 Glass transmissivity of Typical TFSSCs.
Figure 4.12 Cleaning and wet texturing production line.
Figure 4.13 TCO sputtering system (double ZAO targets), Leybold Optical.
Figure 4.14 ZAO rotary target, Leybold Optical.
Figure 4.15 Deposition chamber of PECVD production line in one chamber with several coatings.
Figure 4.16 PECVD technique, horizontal clustering.
Figure 4.17 PECVD technique, vertical folding.
Figure 4.18 PECVD depositing system, linear series.
Figure 4.19 PECVD system, linear parallel, Leybold Optical.
Figure 4.20 Diagramme of PECVD system and deposition chamber, Leybold Optical.
Figure 4.21 BC sputtering system, Leybold Optical.
Figure 4.22 Laser scriber diagramme.
Figure 4.23 Square resistance of TFSSCs measured by four-probe method.
Figure 4.24 Relationship between defect density and the substrate temperature in a-Si.
Figure 4.25 Variation of the deposition rate with plasma excitation frequency.
Figure 4.26 Variation of crystallisation volume fraction XC and the average grain size of the silicon film with plasma excitation frequency.
Figure 4.27 Relationship between the deposition rate (▪), the crystalline phase ratio () of the silicon film and the deposition pressure in the VHF-PECVD technique.
Figure 4.28 Relationship between the absorption coefficient of c-Si, a-Si:H, a-SiGe:H and µc-Si:H and the photon energy.
Figure 4.29 Spectral response of double/triple-junction solar cells.
Figure 4.30 I-V characteristic curve of glow discharge system.
Figure 4.31 Glow space diagramme of glow discharge.
Figure 4.32 Structural diagramme of RF PECVD system.
Figure 4.33 Diagramme of a-Si thin film grown via active group SiH₃.
Figure 4.34 Six basic steps of physical sputtering.
Figure 4.35 A simple parallel metal DC diode sputtering system.
Figure 4.36 RF sputtering system.
Figure 4.37 MC sputtering system.

Chapter 5: High-Efficiency Silicon Solar Cells and Non-Silicon-Based New Solar Cells

Figure 5.1 Different diffusion concentrations of the ‘metal gate electrode contact area’ and the ‘light absorption area’.
Figure 5.2 Structure of LGBC cells.
Figure 5.3 P-type PERL high efficient cells with passivated emitter, boron diffusion on the rear.
Figure 5.4 N-type PERL high efficient cells with passivated emitter and rear boron diffusion.
Figure 5.5 IBC solar cells, SunPower.
Figure 5.6 MWT cells: Emitter wrapped from the front to the backside (principle diagramme).
Figure 5.7 Front/backside of MWT cells.
Figure 5.8 Development roadmap of the solar cell technologies in the upcoming 10 years.
Figure 5.9 Estimated trend of silicon proportion in solar cells in the upcoming years.
Figure 5.10 Structural diagramme of HIT solar cells.
Figure 5.11 Diagramme of LPE growth system.
Figure 5.12 A schematic diagramme of MOCVD systems.
Figure 5.13 Diagram of MBE growth system for growing III–V group materials.
Figure 5.14 Structural diagramme of InGaP/InGaAS/Ge three-junction solar cells.
Figure 5.15 Utilisation of solar spectrum by GaInAs/GaAs/Ge three-junction solar cells (compared with silicon).
Figure 5.16 Structural diagramme of CdTe TFSCs.
Figure 5.17 Comparisons of light absorption coefficient of various semiconductor materials.
Figure 5.18 Structural diagramme of CIGS TFSCs.
Figure 5.19 Diagramme of typical system for Cu, In, Ga and Se co-evaporation.
Figure 5.20 Diagram of H₂Se selenylation system.
Figure 5.21 Flow diagramme of flexible CIGS solar cells.
Figure 5.21 Section of flexible CIGS solar cells.
Figure 5.22 Double-layer heterojunction and basic physical process from photons to electrons in an organic solar cell: (a) Structure of double-layer heterojunction components; (b) diagramme of P/N junction built-in field formed at the electron donor (P)/organic acceptor (N) interface; (c) Basic physical process of photons to electrons.
Figure 5.23 Structure and working principle diagramme of dye-sensitised nano solar cells.
Figure 5.24 Typical structure of perovskite crystal.
Figure 5.25 2D plane structure of perovskite solar cells.
Figure 5.26 Transmission concentrator and PV cell chips.
Figure 5.27 Principle diagramme of camber reflected concentrator.
Figure 5.28 Concentrator and tracking system of concentrator solar cell system.
Figure 5.29 Diagram of quantum well superlattice energy band structure.

Chapter 6: Modules and Arrays of Solar Cells

Figure 6.1 Materials of modules.
Figure 6.2 Structural diagramme of modules composed of solar cell wafers in series.
Figure 6.3 Appearance of flat plate solar cell modules.
Figure 6.4 Structure of double-sided glass solar cell modules.
Figure 6.5 Nonopaque solar cell modules installed in the buildings.
Figure 6.6 Solar cell modules for BIPV (PV shingles, PV curtain walls and PV screens).
Figure 6.7 Hollow, double-sided glass PV modules.
Figure 6.8 Solar ray intensity distribution in a whole day on the ground.
Figure 6.9 Variation of power generation of HIT cells with double-sided structure as the installation angle changes.
Figure 6.10 Layout of the automatic production line of 30–50 MW solar cell modules.
Figure 6.11 Laser scriber for production of solar cell modules.
Figure 6.12 Cell welding table, series welding table and laying work table for production of solar cell modules.
Figure 6.13 Automatic welding methods: (a) hot air; (b) infrared lamp.
Figure 6.14 Automatic system for cell laying and series welding operations.
Figure 6.15 Manual laminator and auto-loading laminator.
Figure 6.16 Solar simulator system for module tests.
Figure 6.17 Turnover trolleys and frame machines for solar cell modules.
Figure 6.18 Automatic tester for solar cell modules.
Figure 6.19 Principle diagramme of electroluminescence for solar cell and module detection.
Figure 6.20 Hot spot effect during module detection by electroluminescence.
Figure 6.21 Silicon wafer defects during module detection by electroluminescence: (a) Uneven resistance; (b) cracks; (c) fragments; (d) broken gate lines; (e) dry welding joints
Figure 6.22 Two common crystalline silicon solar cell modules available in the market nine in series and four in shunt (125 × 125) and 12 in series and 6 in shunt (125 × 125).
Figure 6.23 Effective area of 125 × 125 mm monocrystalline silicon wafer (deducting the rounded angle).
Figure 6.24 Single line diagramme of the solar cell array.

Chapter 7: PV Systems and Grid-Connected Technologies

Figure 7.1 Classification of PV systems.
Figure 7.2 Diagram of a stand-alone power system.
Figure 7.3 Diagram of a grid-connected power system.
Figure 7.4 Power supply types of grid-connected PV systems (a) reverse current system; (b) non-reverse current system.
Figure 7.5 Working principle diagramme of a simple energy storage stand-alone PV system.
Figure 7.6 Protection circuit of PV system (a) c/w insulating transformer; (b) not c/w insulating transformer.
Figure 7.7 Structure and charge/discharge of lithium ion batteries.
Figure 7.8 Structural diagramme of flow batteries.
Figure 7.9 Structural comparisons between electric double-layer super capacitors and electrolyte capacitors. (a) Electrolyte capacitor; (b) Electric double layer super capacitor.
Figure 7.10 Basic structure of fuel cells.
Figure 7.11 Applications of IGBT (frequency and power range).
Figure 7.12 Structural diagramme of IGBT.
Figure 7.13 Equivalent circuit of IGBT.
Figure 7.14 Development history of IGBT.
Figure 7.15 Structural comparisons of planar gate IGBT and trench gate IGBT.
Figure 7.16 Comparisons of PT IGBT and NPT IGBT, PT IGBT (a), NPT IGBT (b).
Figure 7.17 Structural comparisons on FS IGBT and NPT IGBT.
Figure 7.18 Structure of IGBT with trench gate and FS structure (sixth-generation IGBT).
Figure 7.19 IGBT with guard ring.
Figure 7.20 Example of the inverter in the PV system.
Figure 7.21 PWM technologies with single-phase inverter.
Figure 7.22 Process where the comparison between V_m(t) and V_c(t) is carried out to convert the DC input to sinusoidal wave AC output.
Figure 7.23 Schematic diagramme of three-phase full-bridge voltage inverters and output waveform of three-phase SPWM sinusoidal wave.
Figure 7.24 Basic Schematic diagramme of inverter circuit.
Figure 7.25 LVRT requirements on PV systems.
Figure 7.26 Power-voltage curve of solar cell arrays.
Figure 7.27 Identification of maximum output working point of solar cell array by power disturbance observation method.
Figure 7.28 Power optimisation and module intelligent monitoring management.
Figure 7.29 Applications of small-power DC PV systems.
Figure 7.30 Communication relay station and solar lighthouse required of controllers and batteries.
Figure 7.31 Applications of PV systems that need inverters, controllers and energy storage devices.
Figure 7.32 Applications of the PV system with the grid-connected inverter and meters for electricity selling/purchase.
Figure 7.33 Sketch of large-sized grid-connected PV station.
Figure 7.34 Wind power and PV hybrid power system.
Figure 7.35 Stand-alone (off-grid) PV system charging/discharging diagram. (a) DC load only; (b) DC/AC loads.
Figure 7.36 Stand-alone PV system with backup energies (e.g., wind power).
Figure 7.37 Diagram of grid-connected PV system with BAPV.
Figure 7.38 Two applications of PV roof. (a) PV building project, Shanghai World Expo, 2010; (b) Roof c/w thin-film solar cells.
Figure 7.39 PV stations in the agricultural greenhouse and the fish pond.
Figure 7.40 Field environment of PV system.
Figure 7.41 Certificate issued by CQC for PV products.
Figure 7.42 Certification and accreditation management system and execution system of China.

List of Tables

Chapter 1: Basic Physics of Solar Cells

Table 1.1 Future world dnergy demand and renewable resources
Table 1.2 Solar cell development stages
Table 1.3 Solar radiation of the regions in China throughout a year
Table 1.4 Relationship between the base resistivity and the width of the P-N junction depeltion layer in the crystalline silicon solar cell

Chapter 2: Materials of Solar Cells

Table 2.1 Output (10,000 t) and applications of polycrystalline silicon across the globe, 2005–2015
Table 2.2 Output of polycrystalline silicon (t), mainland China, 2001–2013
Table 2.3 Comparisons of polycrystalline silicon output of mainland China with the world, 2009–2013
Table 2.4 Countries and their production methods for low-cost solar-grade polycrystalline silicon in the world
Table 2.5 Main techniques and purity of UMG silicon manufacturers both at home and abroad
Table 2.6 Variation of vapour pressure of various elements with temperature rise Unit: Pa
Table 2.7 Experimental results of boron removal by slag making unit: ppmw
Table 2.8 Solid/liquid segregation coefficients of various impurity elements in silicon
Table 2.9 Equilibrium segregation coefficient of impurities in silicon
Table 2.10 Silane consumption growth with PV industry development in the world in recent years
Table 2.11 GDMS impurity analysis limits (Unit: ppm)
Table 2.12 SIMS impurity analysis limits (Unit: /cm⁻³)

Chapter 3: Preparation Methods of Crystalline Silicon Solar Cells

Table 3.1 Steps and Process Parameters of Monocrystalline Silicon Wafer
Table 3.2 Main data and production capacity of BTU chain-type diffusion furnace
Table 3.3 Procedure and process parameters for PSG removal
Table 3.4 Performance of the solar cell-sorting machine, BACCINI
Table 3.5 Estimates of CSSC cost composition

Chapter 4: Preparation Methods of Thin Film Silicon Solar Cells

Table 4.1 Comparisons of TCO by different deposition techniques
Table 4.2 Characteristics of some TCOs at the ambient temperature
Table 4.3 Basic data of top/middle/bottom cells of triple-junction solar cells

Chapter 6: Modules and Arrays of Solar Cells

Table 6.1 Wind pressure resistance level of building curtain walls
Table 6.2 Impact resistance level of building curtain walls
Table 6.3 Thermal conduction coefficient of building curtain walls
Table 6.4 Characteristics of typical solidification EVA sealing materials
Table 6.5 Main performance of back plate coated with fluorine element
Table 6.6 Specifications and performance of white TPT
Table 6.7 Proportion of common module faults
Table 6.8 Comparisons on the above three macro defect detection techniques
Table 6.9 Specifications of common crystalline silicon solar cell modules
Table 6.10 Cost composition of a module factory, January 2014
Table 6.11 China PV parity development roadmap (generator side)

Chapter 7: PV Systems and Grid-Connected Technologies

Table 7.1 Comparisons of energy storage techniques
Table 7.2 Chinese national standards on the off-grid PV system
Table 7.3 Technical codes on grid-connected PV power in China
Table 7.4 Relevant Chinese national technical codes under approval
Table 7.5 IEC publications related to the off-grid PV system
Table 7.6 IEC publications related to the grid-connected PV system

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Title: Technology, manufacturing and grid connection of photovoltaic solar cells / by Guangyu Wang.

Description: Hoboken, NJ : John Wiley & Sons, 2018. | Includes bibliographical references and index. |

Identifiers: LCCN 2017042881 (print) | LCCN 2017055841 (ebook) | ISBN 9781119035190 (pdf) | ISBN 9781119035206 (epub) | ISBN 9781119035176 (cloth)

Subjects: LCSH: Solar cells. | Photovoltaic cells. | Photovoltaic power systems.

Classification: LCC TK2960 (ebook) | LCC TK2960 .W35 2018 (print) | DDC 621.31/244-dc23

About the Author

Guangyu Wang was born in 1943, Suzhou, China. He was graduated from Suzhou High School in 1960, and Peking University of Science and Technology in 1965, respectively. After graduation, he joined Emei semiconductor material research institute and worked on the process development and production. He received his M.Sc. and Ph.D. degrees in semiconductor material and device from Shanghai Institute of Metallurgy, Chinese Academy of Sciences in 1981 and 1985, respectively. He is now a research professor at Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences (CAS). He is the director of East-China High-Tech Innovation Park in Jiangsu province, China. He is a vice chairman of Shanghai Optoelectronics Trade Association (SOTA), responsible for PV industry. He has won several National Awards and enjoyed special government allowances of the State Council.

The author is grateful to Dr. Bingwen Liang for his assistance with translating and proof-reading. Dr Liang received his Ph.D. degree in Applied Physics from University of California at San Diego (UCSD) in 1993. After graduation, he joined HP's Optoelectronics Division (OED) in San Jose, California and worked on super-high-brightness light-emitting diode (LED) process development and production. In 2008, as a full professor Dr. Liang joined Suzhou Institute of Nano-Tech and Nano- Bionics (SINANO), Chinese Academy of Sciences (CAS) and later was appointed as the Director of Technology Transfer Center. He has more than 60 journal and conference publications and has given a number of conference presentations including invited talks. He co-authored the Chapter of “Semiconductor Lasers” in the Handbook of Optical Components and Engineering, John Wiley, New York, 2003. He has been granted six (6) US patents, more than sixty (60) China patents and about twenty five (25) China pending patents. He has more than twenty three (23) years of experience in III-V compound semiconductor materials and devices. His core expertise includes optoelectronic materials and devices for lighting, displays and green-energy applications.

Preface

In August 2014, through the recommendation of China Electric Power Press, the English version of Technology, Manufacturing and Grid Connection of Photovoltaic Solar Cells won the favour of U.S. publisher, John Wiley & Sons, and both parties decided to jointly publish the book. The original Chinese version of the book was completed in September 2010 and since then the photovoltaic (PV) industry has developed very rapidly. In 2010, polycrystalline silicon, the main raw material of PV solar cells, was mainly produced in foreign countries and China's PV power generation accounted for a small proportion of the world PV market. However, in 2014, both China's production of polycrystalline silicon and newly installed capacity of PV power were ranked first in the world. In addition, as China made major progress in the R&D of solar cell research, the core component of PV power generation, efficient silicon solar cell, compound thin-film solar cell, organic solar cell, dye solar cell and perovskite solar cell were developed one after another. PV internet technology was also beginning to take shape and the cost of PV power generation was close to the cost of conventional energy power generation.

This book has a total of seven chapters. Chapter 1, Basic Physics of Solar Cells, describes the PV effect resulted from solar spectral radiation to semiconductor materials and illustrates the basic principle of P-N junction and heterojunction semiconductor solar cell power generation. Chapter 2, Materials of Solar Cells, introduces polycrystalline silicon, monocrystalline silicon, thin-film silicon and compound materials commonly used in the PV industry and impurity analysis methods, especially emphasising low-cost and low-pollution solar-grade materials. Chapter 3, Preparation Methods of Crystalline Silicon Solar Cells, elaborates on the production process and equipment of crystal silicon solar cell which boasts the largest production and widest application in the current PV industry, with a market share of 80%. Chapter 4, Preparation Methods of Thin-film Silicon Solar Cells, discusses the characteristics of thin-film silicon, solar cell optical attenuation mechanism and the device and the principle of thin-film deposition, making theoretical preparations for the introduction of non-silicon thin-film solar cells in Chapter 5, High Efficiency Silicon Solar Cells and Non-Silicon-Based New Solar Cells, which can be divided into two sections. The first section mainly focuses on introducing efficient silicon solar cells such as passivation emitter solar cell, the interdigitated back contact (IBC) solar cell and amorphous silicon/crystalline silicon heterojunction solar cell based on the introduction of the traditional silicon solar cells in Chapters 3 and 4. The second section introduces the non-silicon-based III-V compound semiconductor multi-junction solar cell, II-VI semiconductor thin-film solar cell, organic solar cell, dye-sensitised solar cell, perovskite solar cell, concentrator solar cell and multiple quantum well solar cell, some of which are likely to develop very well in the next 10 years. Chapter 6, Modules and Arrays of Solar Cells, mainly describes module packaging materials, process and equipment. As modules are the major products exchanged by solar cell manufacturers in the market, this chapter focuses on the introduction of the reliability of the modules and the detection following packaging. Chapter 7, PV Systems and Grid-connected Technologies, first introduces multiple PV systems applicable to different environments and then introduces the main components in the PV system, except social cell modules such as energy storage batteries, inverters and controllers. In addition, it discusses the possible impact on the public power grid of the PV and other new energy source grid integration and how to pass product testing and certification and get access to the smart grid. Finally, it provides an overview of China's uneven development course of PV power generation in the past 10 years.

The PV industry has developed at a rapid speed that is rare in the modern industry and is even unmatched by the semiconductor industry. Since the beginning of the twenty-first century, all countries in the world have attached great importance to the imminent exhaustion of the world's fossil energy and the problems, such as environmental pollution and climate change resulted from it, and have fully realised it is urgent and necessary to vigourously develop renewable energy such as solar energy. It's true that China still has a long way to go before we can use new energy, including PV energy, as alternative energy sources, but PV power generation has promising prospects and is developing at an amazing speed. As new energy is one of the heatedly discussed topics in the twenty-first century, I believe PV power generation and grid connection technology will be constantly updated by new research and development.

In the end, I would like to thank Dr. Liang Bingwen for reviewing some chapters of this book and Professor Jiang Xinyuan's valuable advice for this book. It makes me confident that I can finish the book.