Photovoltaic modules, also known as solar panels, consist of multiple solar cells of identical size and quantity. Within photovoltaic systems, these modules typically comprise silicon wafers, glass, EVA laminate, and backsheets. Silicon wafers serve as the core material of photovoltaic modules, accounting for approximately 90% of the total module cost, thus demanding high quality standards. Glass and EVA film each contribute about 10% to the total cost, significantly impacting the module's performance and lifespan.

Photovoltaic modules find extensive applications across various sectors, including residential lighting, electric vehicles, communication base stations, and solar-powered agricultural greenhouses.

Primary Materials of Photovoltaic Modules

Solar Cells

The core component of photovoltaic modules, typically made from high-purity monocrystalline or polycrystalline silicon. Through processes like doping and junction formation, they create PN junctions responsible for converting solar energy into electricity.

Tin-Coated Copper Ribbon (Photovoltaic Busbar)

Used to connect solar cells, serving as a conductor and current collector.

EVA

A copolymer of ethylene and vinyl acetate, serving as the encapsulation film. It bonds the cell, glass, and backsheet while protecting the cell's electrical properties.

Backsheet

Protects the rear surface of the PV module against environmental corrosion, such as humidity and heat, while enhancing light absorption efficiency and insulation performance.

Tempered Glass

Serves as the structural support for photovoltaic modules, enhancing load-bearing capacity while offering high light transmittance and effective water/gas barrier properties.

Silicone Sealant

Used for bonding and sealing photovoltaic modules, enhancing UV resistance.

Aluminum Alloy Frame

Protects the glass edges, enhances the module's sealing performance and mechanical strength, and facilitates installation and transportation.

Junction Box

Contains the connectors for the solar panel, used to direct electrical energy to external devices.

These materials collectively form the fundamental architecture of photovoltaic modules, ensuring the efficient operation and long-term stability of solar panels.

Analysis of Photovoltaic Module Manufacturing Process Steps

Silicon Wafer Preparation

The core material for photovoltaic modules is silicon wafers, which include both monocrystalline and polycrystalline silicon.

Cell Fabrication

Silicon wafers undergo processing into photovoltaic cells through foundational steps including cleaning, cutting, etching, diffusion, and deposition. The critical step is the diffusion process, which forms the PN junction structure.

Module Encapsulation

Pre-treated stacked layers undergo surface impurity removal and interlayer adhesion inspection; then sent to a laminator where EVA adhesive film melts under high temperature (approx. 130-150°C) and pressure, fully filling gaps and bonding layers. After lamination, modules enter a curing oven for temperature stabilization, allowing EVA to fully cross-link and solidify into a stable monolithic structure while ensuring sealing integrity and weather resistance.

Cell Testing and Sorting

Classify cells based on performance parameters to optimize utilization rates.

Front Side Soldering

Solder busbars (tin-plated copper strips) to the front main grid lines of each cell, preparing for series connection.

Back Side Series Connection

Use a soldering iron and solder wire to sequentially connect cells in series, forming module strings, and solder lead wires.

Lamination Layup

Arrange the strung cells, glass, EVA, glass fiber, and backsheet in specific layers for lamination preparation.

Framing and Inspection

After trimming and framing (including junction box installation), inspect the solar module for anomalies like microcracks, fragments, cold solder joints, or open circuits. Conduct power and visual tests; ship only qualified modules.

These process steps ensure the quality and performance of photovoltaic modules, enabling efficient conversion of solar energy into electricity.