Photovoltaic Materials and Cell Technology

Photovoltaic Materials and Cell Technology

PV (Photovoltaic)

Techniques or devices for the direct conversion of light energy into electrical energy

c-Si (Crystalline Silicon)

The most commonly used material for photovoltaic cells, including monocrystalline and polycrystalline silicon.

mono-Si (Monocrystalline Silicon)

Silicon materials consisting of a single crystal structure are more efficient.

poly-Si (Polycrystalline Silicon)

Silicon material made up of multiple grains, which is less expensive but slightly less efficient.

a-Si (Amorphous Silicon)

A thin-film solar cell material with good low-light performance

PERC (Passivated Emitter and Rear Cell)

A high efficiency crystalline silicon solar cell structure

TOPCON (Tunnel Oxide Passivated Contact)

A new high-efficiency crystalline silicon solar cell technology

HJT (Heterojunction Technology)

High-efficiency solar cell technology combining the advantages of crystalline and amorphous silicon

IBC (Interdigitated Back Contact)

An efficient cell structure with all electrodes on the back of the cell

BSR (Back Surface Reflector)

Cell backside structure for improved long-wavelength light absorption

EVA (Ethylene Vinyl Acetate)

Commonly used encapsulation material for photovoltaic modules, with good transparency and weather resistance.

TPT (Tedlar-PET-Tedlar)

Commonly used backsheet materials for photovoltaic modules

POE (Polyolefin Elastomer)

A new photovoltaic encapsulation material with excellent weather resistance

CdTe (Cadmium Telluride)

A thin-film solar cell material with high conversion efficiency

CIGS (Copper Indium Gallium Selenide)

An efficient thin film solar cell material

Photovoltaic Performance Parameters and Test Conditions

VOC (Open-Circuit Voltage)

Maximum output voltage of a solar cell when not connected to a load (open circuit state)

ISC (Short-Circuit Current)

Maximum output current of solar cell under short-circuit conditions

MPP (Maximum Power Point)

Operating point at which solar cell output is maximized

STC (Standard Test Conditions)

Standard environmental conditions for testing PV module performance: Irradiance: 1000 W/m² (1 kW/m²), Cell Temperature: 25°C (77°F), Air Mass: AM1.5G

NOCT (Nominal Operating Cell Temperature）

Test conditions closer to the real working environment: Irradiance: 800 W/m², Ambient Temperature: 68°F (20°C), Wind Speed: 1 m/s.

AM (Air Mass)

The length of the path of sunlight through the atmosphere, which affects the spectral distribution

η (Efficiency)

An indicator of the ability of a photovoltaic module to convert light energy into electrical energy.

FF (Fill Factor)

A measure of the ratio of the actual maximum output power of a solar cell to its theoretical maximum output power

DNI (Direct Normal Irradiance)

Intensity of direct radiation received in a plane perpendicular to the direction of the sun’s rays

GHI (Global Horizontal Irradiance)

Total intensity of radiation received on the horizontal plane, including direct and scattered radiation

LID (Light Induced Degradation)

Performance degradation of photovoltaic modules during the initial use phase

PID (Potential Induced Degradation)

Performance degradation of photovoltaic modules in high voltage environments

LeTID (Light and Elevated Temperature Induced Degradation)

Performance degradation of poly crystalline silicon cells under light and high temperature conditions

TC (Thermal Cycling)

Test Methods for Evaluating Temperature Resistance of Photovoltaic Modules

HF (Humidity Freeze)

Test Methods for Evaluating the Resistance of Photovoltaic Modules to Humidity, Heat and Freezing

DH (Damp Heat)

Test Methods for Evaluating PV Module Resistance to High Temperature and Humidity

kWp (Kilowatt Peak)

Maximum output power of the PV system under standard test conditions

kWh (Kilowatt Hour)

A unit of energy that represents the amount of energy produced by one kilowatt of power in one hour.

Photovoltaic Installation

BOS (Balance of System)

Components of a photovoltaic system other than photovoltaic modules

BAPV (Building Applied Photovoltaics)

Technologies for installing solar panels on the surface of existing buildings

BIPV (Building Integrated Photovoltaics)

Technologies for integrating solar photovoltaic systems into building structures

EPC (Engineering, Procurement, and Construction)

Overall service model for the construction of photovoltaic power plants

FPV (Floating Photovoltaic)

Photovoltaic systems installed on water, usually built on lakes, reservoirs or oceans

CPV (Centralized Photovoltaic)

Large-scale ground-mounted PV plants, usually directly connected to the grid

DPV (Distributed Photovoltaic)

Small-scale photovoltaic systems, usually mounted on or near buildings, consume electricity nearby

String

Circuit formed by multiple PV modules connected in series

Array

Multiple PV strings or modules connected in parallel to form a larger system

Combiner Box

Junction box for combining the outputs of multiple PV strings

JB (Junction Box)

Sealed box for electrical connection on the backside of the PV module

GCR (Ground Coverage Ratio)

Ratio of module area to total floor space

ATS (Automatic Tracking System)

A system that automatically adjusts the angle of PV modules according to the position of the sun

TPM (Tilt and Pan Mechanism)

Racking systems that allow the angle and orientation of PV modules to be adjusted

SAT (Site Acceptance Test)

Performance and security testing after installation

AOI (Angle of Incidence)

The angle between the sunlight and the surface of the PV module affects the design of the mounting.

BOS (Balance of System)

All other components of a photovoltaic system except for the photovoltaic modules, including racking

 

Photovoltaic System Performance and Economic Indicators

LCOE (Levelized Cost of Energy)

Important metrics for measuring the economics of photovoltaic power generation

PR (Performance Ratio)

Ratio of actual power generation to theoretical power generation of PV system

ROI (Return on Investment)

Important indicators for evaluating the economics of PV systems.

Photovoltaic Power Systems and Grid Connection

DC (Direct Current)

Current flowing in a single direction, raw output of the PV module

AC (Alternating Current)

The output of the current, which changes direction periodically, is converted by an inverter.

MPPT (Maximum Power Point Tracking)   

Techniques for regulating the operating state of the system to obtain maximum output power

DG (Distributed Generation)

Small-scale power generation facilities close to the consumer, e.g., rooftop photovoltaic systems

FIT (Feed-in Tariff)

Purchase price of electricity generated by grid-connected PV systems by the grid company

PCC (Point of Common Coupling)

Connection point of distributed generation systems to the grid

RPS (Renewable Portfolio Standard)

Policies requiring electric utilities to use a certain percentage of renewable energy sources

PPA (Power Purchase Agreement)

Commonly used business models for photovoltaic power generation projects.

Electrical Safety and Protection

RCD (Residual Current Device)

Safety device that detects current imbalance and cuts off the circuit in case of danger

MCB (Miniature Circuit Breaker)

Switching devices for protection of circuits against overloads and short circuits

SPD (Surge Protection Device)

Device to protect electrical equipment from voltage surges

GFDI (Ground Fault Detection and Interruption)

Safety devices for detecting and disconnecting ground faults in photovoltaic systems

AFDI (Arc Fault Detectionand Interruption)

Safety features for recognizing and interrupting dangerous arcs in photovoltaic systems
ISO (Isolation)

Function to safely disconnect the PV system from the grid during maintenance