Custom Solar Panel

How to Choose Between ETFE Solar Panels and PET Solar Panels?

The key to choosing between ETFE and PET lies in your intended use and duration: choose ETFE for long-term outdoor applications, and PET for short-term or indoor use.

While both are lightweight polymer materials, they differ significantly in performance and application. ETFE is a more modern and durable option, while PET is primarily geared towards scenarios where cost and lifespan are less critical.

ETFE Solar Panel

To make this clearer, I’ve summarized their key differences in the table below:

Comparison Dimensions	ETFE (Ethylene-Tetrafluoroethylene Copolymer)	PET (Polyethylene Terephthalate)
Positioning and Trends	Mainstream high-performance material, used as a lightweight front panel to replace glass	Early or basic material, mostly used in low-cost, low-power products
Typical Lifespan	7-10 years, strong weather resistance	1-3 years, faster aging in outdoor environments
Light Transmittance	Very High (95%)	Moderate (85-90%)
Surface Characteristics	Hydrophobic, dustproof, strong self-cleaning ability, not easy to accumulate dust	High surface energy, easily attracts dust, and frosted versions have a risk of shedding sand
Weather Resistance and Aging Resistance	Excellent, UV resistant, resistant to damp heat, low risk of yellowing in long-term outdoor use	Poor, PET substrate is not resistant to ultraviolet light, must rely on other materials for protection before outdoor use
Flexibility	Bendable, suitable for curved surfaces of a certain curvature	Has some flexibility, but not as good as ETFE, easily damaged by repeated bending
Cost	Higher, higher technical content and material cost	Budget-friendly
Main applications	IoT devices, wireless sensors, marine, RVs, camping, outdoor adventure, portable charging bags, lightweight roofs, BIPV (Building Integrated Photovoltaics)	solar calculators, solar lawn lights, low-power power banks, children’s toys, and other indoor or short-term outdoor electronic products

How to choose?
1. Choose ETFE If:
You need durability: ETFE is self-cleaning, corrosion-resistant, and withstands harsh environments.
It’s a permanent installation: Excellent for boats, RV roofs, or off-grid locations where you won’t replace panels often.
You want higher efficiency: Higher transparency

2. Choose PET If:
You are on a tight budget: PET panels are much cheaper to purchase.
It’s for temporary use: Ideal for short-term camping, hiking, or portable charging.
Storage is easy: Since they won’t last long outdoors, they are fine if used occasionally and stored indoors.

Critical Considerations
Lifespan & Degradation: PET, being a plastic film, will become brittle and hazy, often developing a “milky” appearance after 0.5–2 years.
Performance: ETFE surfaces are textured to catch more light, offering better efficiency in lower light conditions.
Safety: PET panels are less thermally stable compared to the high-heat resistance of ETFE.

Summary: choose ETFE solar panels for long-term, permanent, or harsh outdoor installations (7–10 year lifespan) due to superior durability, high transparency (95%), and self-cleaning properties. Choose PET solar panels for budget-friendly, temporary, or portable uses (1–3 year lifespan), as they are cheaper but less UV-resistant and durable.

WSL Solar has been a quality and professional manufacturer of custom solar panels, solar mini panels, IoT solar panels and solar solution provider in China since 2006.
Email: info@wsl-solar.com

https://www.wsl-solar.com

Source of origin: https://www.wsl-solar.com/Product_News/2026/0420/ETFE-Solar-Panels-and-PET-Solar-Panels.html

Automated Production and Testing Equipment for Custom Solar Panels

WSL Solar continuously introduces industry-leading production and testing equipment – this not only significantly improves production efficiency but also ensures that every product possesses highly consistent and superior performance. It is this dedication to quality and technology that allows us to consistently deliver high-quality, high-efficiency customized solar panels, while providing reliable solar solutions, earning the trust of a growing number of customers.

Choosing WSL Solar means choosing high efficiency, stability, and long-term value. Welcome to contact us for high quality custom solar panels.

WSL Solar has been a quality and professional manufacturer of custom solar panels, solar mini panels, IoT solar panels and solar solution provider in China since 2006.

Email: info@wsl-solar.com

https://www.wsl-solar.com

The Working Principle of Producing Back-contact Solar Panels Using SMT Technology

The core of the surface mount technology (SMT) manufacturing process for back contact (BC) solar panels lies in transferring all the main grid lines, originally located on the front, to the back, using a PCB (printed circuit board)-like process to achieve stress-free interconnection of the solar cells.

This process mainly consists of the following key steps, its ingenuity lying in replacing traditional solder ribbons with conductive backplates and conductive adhesive.

Working Principle and Core Steps

1. Prefabricated Conductive Backplate (equivalent to a “PCB” in SMT)
Principle: In SMT, electronic components are mounted on a pre-fabricated PCB circuit board. Similarly, manufacturers prefabricate a “conductive backplate,” an insulating board with specific copper foil circuitry.
Function: The circuitry on this backplate precisely corresponds to the positive and negative terminals on the back of each solar cell. It not only conducts electricity but also provides structural support for the entire assembly.

2. Precise Placement of Solar Cells (equivalent to “SMT placement”)
Principle: This is consistent with the logic of an SMT placement machine precisely placing components onto pads. Using high-precision automated equipment, the back-contact solar cells are attached to their corresponding positions on the conductive backsheet according to a pre-designed spacing.
Advantages: Because all electrodes are placed back-side down, there is no obstruction on the front, completely eliminating the 2%-3% light loss caused by the front-side main grid lines of traditional cells. This not only improves efficiency but also makes the module appearance more uniform and aesthetically pleasing.

3. Conductive Interconnection (equivalent to “reflow soldering” in SMT)
Principle: This is the core technology, using conductive adhesive (ICA) or anisotropic conductive adhesive (ACA) instead of traditional high-temperature soldering.
Process: The conductive adhesive is applied between the electrodes of the solar cell and the backsheet circuitry through printing or dispensing. Then, it is simultaneously heated and pressurized in a laminator, where the conductive adhesive cures under hot-press conditions, forming a stable and flexible electrical connection.
Significant advantages: Traditional high-temperature soldering is prone to microcracks due to thermal stress, while this low-temperature conductive adhesive process has almost zero stress, allowing the use of thinner silicon wafers (down to 180 micrometers) and significantly improving the long-term reliability of components.

4. Integrated Encapsulation
Principle: The stacked “glass – encapsulating film (EVA/POE) – interconnected solar cells and backsheet” are fed into a laminator. Under vacuum and high temperature, the encapsulating film melts and bonds all materials tightly together to form the final solar module.

Why choose SMT technology instead of traditional soldering?

The performance improvement brought by this process is revolutionary. Its main advantages are:

Features	Traditional solder ribbon process	SMT conductive backplane process
Shading Loss	Front main busbars block approximately 3% of sunlight	Zero shading, all electrodes are located on the back, maximizing the light-receiving area
Stress and Microcracks	High-temperature soldering causes high stress, easily leading to microcracks.	Stress-free connection significantly reduces breakage rate and microcrack risk.
Appearance	Visible silver-white solder ribbon	All-black/solid color, neat and aesthetically pleasing.
Series Resistance	Higher resistance at solder ribbon connection points	Lower contact resistance, higher conductivity, and higher module power
Wafer Thickness	Limited by the soldering process, cannot be too thin.	Compatible with ultra-thin wafers (<180µm), further reducing costs

Through this innovative interconnection method, back-contact technology not only achieves higher photoelectric conversion efficiency but also endows photovoltaic modules with stronger mechanical properties and a better appearance, making it one of the mainstream technologies for high-efficiency photovoltaic modules.

Back Contact Solar Panel

Posted by Carrie Wong / WSL Solar

WSL Solar has been a quality and professional manufacturer of custom solar panels, solar mini panels, IoT solar panels and solar solution provider in China since 2006.

https://www.wsl-solar.com

9V 2.3W Solar Panel

Key Features:
– Utilize high efficiency mono PERC solar cell, up to 23.5% efficiency
– Laminated by tempered glass, rigid, durable and long lasting
– Waterproof, scratch resistant, and UV resistant
– Customized solar panels for industrial use

Description:
9V 2.3W Solar Panel

This 2.3W solar panel utilizes high efficiency mono PERC solar cells with efficiency up to 23.5%, to ensure its high output. It is laminated by tempered glass to protect the solar cells inside, making it rigid, durable and long lasting. This tailor-made solar panel is waterproof, scratch resistant, and UV resistant, specially designed for long term outdoor use in any challenging condition.

Applications:
Tempered glass solar panels are widely used in IoT applications, marine buoys, wireless sensors, traffic warning devise, GPS devices, asset tracking, electric fence chargers, outdoor lighting systems, weather monitoring systems etc.

Solar Panel Specification

Item No.	WSL-C044
Solar Panel Size	128.84×128.84×3.5mm
Peak Power (Pmax)	2.3W
Voltage at Pmax (Vmp)	9V
Current at Pmax (Imp)	256mA
Open Circuit Voltage (Voc)	10.8V
Short Circuit Current (Isc)	282mA
Solar Cell Type	Mono PERC Solar Cell
Power Tolerance	±5%
Encapsulation method	3.2mm Tempered glass
Back sheet	TPT
Product Warranty	5 Years
Lead time	25 Days
Storage temperature	-40°C ~ 85°C
Working temperature	-40°C ~ 85°C
Standard Test Conditions (STC)	1000W/m2, 1.5AM, 25°C Cell temperature

What Materials are Solar Panels Made of?

Solar panels are composed of several materials, each playing a crucial role in the panel’s functionality, durability, and efficiency. Here are the primary materials used in the construction of solar panels:

1. Photovoltaic (PV) Cells:
   – Silicon: The most common material for PV cells. It can be monocrystalline, polycrystalline, or amorphous.
   – Cadmium Telluride (CdTe): Used in thin-film solar panels.
   – Copper Indium Gallium Selenide (CIGS): Another material used in thin-film solar panels.
   – Perovskite: An emerging material with high potential efficiency, still under research and development.

2. Encapsulation Material:
   – Ethylene-Vinyl Acetate (EVA): A transparent polymer that encapsulates the PV cells, protecting them from moisture and mechanical damage.

3. Backsheet:
   – Polymer Films: Typically made from materials like Tedlar (PVF), polyester, or polyvinyl fluoride (PVDF). The backsheet provides electrical insulation and protects the back of the panel from environmental factors.

4. Frame:
   – Aluminum: The most common material for the frame due to its lightweight, durability, and resistance to corrosion. The frame provides structural support and facilitates mounting.

5. Glass Cover:
   – Tempered Glass: High-strength, low-iron tempered glass is used as the front cover. It protects the PV cells from physical damage and environmental factors while allowing maximum light transmission.

6. Junction Box:
   – Plastic and Metal: The junction box is typically made from durable plastics and contains metal connectors. It houses the electrical connections and provides a safe interface for wiring.

7. Interconnectors:
   – Copper or Silver: These materials are used for the thin strips that connect individual solar cells within the panel, facilitating the flow of electricity.

8. Adhesives and Sealants:
   – Silicone and Other Polymers: Used to bond different layers of the solar panel together and to seal edges, ensuring durability and protection against moisture ingress.

9. Anti-Reflective Coating:
   – Silicon Nitride or Titanium Dioxide: Applied to the surface of the glass to reduce reflection and increase light absorption by the PV cells.

Summary of Material Functions:
– PV Cells: Convert sunlight into electricity.
– EVA Encapsulation: Protects cells and ensures durability.
– Backsheet: Provides electrical insulation and environmental protection.
– Frame: Offers structural support and facilitates installation.
– Glass Cover: Protects the panel and maximizes light transmission.
– Junction Box: Houses electrical connections.
– Interconnectors: Facilitate electrical flow between cells.
– Adhesives and Sealants: Ensure panel integrity and protection.
– Anti-Reflective Coating: Enhances light absorption.

These materials work together to ensure that solar panels are efficient, durable, and capable of withstanding various environmental conditions over their lifespan.

Posted by Carrie Wong / WSL Solar
WSL Solar has been a quality and professional manufacturer of custom solar panels, solar mini panels, IoT solar panels and solar solution provider in China since 2006.
https://www.wsl-solar.com

How Solar Cell Laser Cutting Machine Works?

How laser cutting machine works to cut solar cells into small pieces according to your solar panel design?

Cutting solar cells into small pieces is a critical process in solar panel manufacturing, especially for high-efficiency custom solar panels with specific designs. Here’s a detailed breakdown of how laser cutting works for solar cells.

The Core Principle: Controlled-Fracture Cleaving (for Monocrystalline Cells)

The most common method doesn’t “burn” through the silicon like a traditional laser cutter might with metal. Instead, it uses a highly focused, low-power laser to create a controlled thermal stress that induces a perfectly clean split along the crystal lattice. This is known as “laser scribing and cleaving” or “laser thermal separation.”

Step-by-Step Process

1. Design & Programming

Your solar panel design is translated into a cutting path by CAD/CAM software.
The software accounts for the wafer’s thickness, material properties, and the required edge quality to minimize electrical losses.

2. Laser Scribing (The Key Step)

A short-pulse, low-power infrared (IR) laser is focused to an extremely fine spot on the surface of the silicon wafer.
The laser rapidly heats a tiny, localized volume of silicon (to over 1000°C) along the desired cut line.
This creates micro-cracks or modifies the material structure along a precise, shallow path (the “scribe line”). The depth is carefully controlled – typically only 10-30% of the wafer’s thickness.
Crucially, the laser does NOT vaporize the material. It creates internal stress and a weakened zone.

3. Cleaving / Breaking

After scribing, a mechanical breaking step is often used.
A controlled bending force applies pressure along the scribe line.
Due to the induced stress and the guided micro-cracks, the silicon wafer fractures perfectly along the laser-defined path, following its crystalline structure.
This results in a clean, smooth edge with minimal micro-cracks and no thermal damage zone (HAZ) that would reduce cell efficiency.

Why Laser Cutting is Superior for Solar Cells (Compared to Mechanical Saws)

Feature	Laser Scribing & Cleaving	Mechanical Diamond Saw/Scribing
Material Loss (Kerf)	Minimal (only the laser scribe line). Saves expensive silicon.	Significant (the width of the diamond blade). Wastes material.
Edge Quality	Very clean, smooth, low micro-crack depth. Higher mechanical strength.	Rougher, more micro-cracks, weaker edges prone to chipping.
Precision & Flexibility	Extremely high. Can cut complex shapes, curves, and very small shingles easily.	Low flexibility, typically only straight lines.
Throughput & Speed	Very high speed (meters per second). Non-contact process.	Slower, mechanical wear on blades.
Dust & Contamination	Almost none for the scribing step. Clean process.	Generates silicon slurry/dust that must be cleaned, causing contamination.
Thin Wafer Handling	Excellent. The only viable method for wafers <150μm thick without breakage.	High breakage rates on very thin wafers.

Critical Requirements for the Laser Process

Ultra-Precision: Cutting must be accurate to within microns to ensure cells are identical for automated stringing.
Minimal Heat Affected Zone (HAZ): The laser must not overheat the silicon, as heat creates defects that trap electrons, killing cell efficiency.
Strength Preservation: The cut edge must remain strong to survive the subsequent manufacturing processes (transport, stringing, lamination).

Summary
In essence, a solar cell laser cutting machine uses a low-power, focused laser to “guide” a fracture through the crystalline silicon, rather than melting its way through. This cold-cutting process maximizes material yield, preserves the electrical quality of the silicon, and enables the intricate cell designs needed for today’s high-efficiency, high-power solar panels. It is an enabling technology for the continuous improvement in solar panel performance and cost-effectiveness.

Source of origin: https://www.wsl-solar.com/Industry_News/2025/1217/how-solar-cell-laser-cutting-machine-wor.html

What is the Role of EVA in Solar Panels?

EVA (Ethylene Vinyl Acetate) serves as a protective encapsulant in solar panels, shielding the solar cells from moisture, dust, dirt, and physical damage. It is a transparent, adhesive thermoplastic sheet that holds the solar cells in place between the glass and the backsheet, while also allowing sunlight to pass through to the cells. Its role is crucial for maintaining the solar panel’s efficiency and ensuring its long-term durability and performance.

Key roles of EVA

Protection: EVA acts as a protective barrier against environmental factors like moisture, dirt, and humidity, which can degrade the solar cells over time.
Adhesion and support: It provides a strong adhesive bond that holds the solar cells securely between the front glass and the backsheet, preventing them from shifting or becoming damaged.
Optical transparency: The film is transparent, allowing sunlight to pass through to the solar cells, which is essential for energy production.
Durability: EVA is designed to be durable and has a long lifespan, contributing significantly to the longevity of the solar panel’s performance.
Insulation: It helps to insulate the cells and their circuits, which can soften shocks and vibrations.

How it works

During the manufacturing process, solar cells are placed between two sheets of EVA film. The sheets are then heated and laminated, which causes the EVA to become a clear, adhesive, and protective film that seals the cells in place.

Source of origin: https://www.wsl-solar.com/Industry_News/2025/1125/what-is-the-role-of-EVA-in-solar-panels.html

What is the Assembly Process of a Custom Solar Panel?

The assembly process of a small, custom solar panel involves preparing the materials, electrically connecting the solar cells, encapsulating them for protection, framing the unit, and performing final testing.

Materials Needed

Solar cells: The core components that convert light into electricity. Monocrystalline or polycrystalline, typically 0.5V each. The number determines the voltage (e.g., 36 cells for an ~18V panel).
Encapsulant (EVA film): Ethylene Vinyl Acetate, a clear material that bonds and protects the cells. They become clear when heated.
Cover (Tempered glass or clear plastic): Protects the front from weather and impact.
Backsheet: A durable polymer layer on the back for insulation and moisture protection.
Frame (Aluminum or wood): Provides structural integrity and a mounting point.
Tabbing and bus wire: Flat, coated copper wires for electrical connections.
Junction box: Houses the electrical connections and bypass diodes.
Sealant (Silicone/Epoxy): Used for sealing edges and the junction box to prevent water intrusion.
Soldering iron and solder: For making the electrical connections.

Assembly Steps

Preparation and Template Creation: A template is created to ensure the correct and even placement of the solar cells on a backing board.
Cell Stringing (Connecting Cells): Individual solar cells are connected in series (positive to negative) using tabbing wire and a soldering iron to achieve the desired voltage. The size of the cell determines the amperage, while the number of cells in series determines the voltage.
Laying Up the Panel: The stack of materials is layered in the following order: glass, a layer of EVA film, the interconnected solar cells, a second layer of EVA film, and finally the backsheet.
Bussing Soldering: The strings of cells are connected to each other using a thicker bus wire to form the complete electrical circuit.
Lamination: The layered panel assembly is placed in a laminator (or sealed manually with even pressure and a clear cover) under vacuum and high temperature. This melts the EVA, encapsulating the cells and bonding all the layers together for durability and weather resistance.
Trimming and Framing: Any excess encapsulant material around the edges is trimmed off. The laminated unit is then fitted into a protective aluminum or wooden frame.
Junction Box Installation: A junction box is attached to the back of the panel and the main positive and negative output wires are connected to it. A blocking diode may be included here to prevent current backflow. The box and edges are sealed with silicone or epoxy.
Testing and Quality Control: The finished panel undergoes electrical tests, such as a sun simulator test and an electroluminescence (EL) test, to measure its performance and check for any micro-cracks or defects.
Final Steps: The panel is cleaned, labeled with its specifications, and packaged for use.

What are 12BB Solar Cells?

12BB (12 busbar) solar cells use multi-busbar (MBB) technology to collect electricity from the solar cell, which increases efficiency and power output compared to traditional designs with fewer busbars. The increased number of busbars shortens the electrical path, which reduces resistance and power loss. This also enhances reliability, making the cells more resistant to cracking and better at performing in low-light conditions.

1. The Core Concept: What are Busbars (BB)?
A standard solar cell generates electricity when sunlight hits it. This electricity needs to be collected and channeled out of the cell. This is the job of the fingers and the busbars.

Fingers: The very fine, hair-thin lines that cover the cell. They collect the electricity.
Busbars (BBs): The wider, more prominent lines that run perpendicular to the fingers. They act as the main “highways” that gather the current from all the fingers and transport it to the tabbing wires, which connect the cells together in a module.

So, a 12BB cell simply has 12 of these main silver highways on its surface.

2. The Evolution: From 2BB to 5BB, 9BB, 12BB, and Beyond
The number of busbars has been steadily increasing over the years as manufacturing technology has advanced.

2BB to 5BB: This was the standard for a long time. Fewer, thicker busbars were easier to manufacture.
9BB, 12BB, 15BB, etc.: The current industry trend is to move to more, but thinner and finer, busbars.

3. Key Advantages of 12BB Solar Cells
Why is moving to more busbars beneficial? The primary goals are higher efficiency and increased reliability.
1). Higher Efficiency & Power Output

Reduced Electrical Resistance: Electricity has to travel a shorter distance from where it’s generated to the nearest busbar. Shorter travel paths mean less energy is lost as heat (a phenomenon called resistive loss).
Better Current Collection: With more collection points, the cell can collect current more uniformly and effectively, especially in low-light conditions.
Reduced Shading: Although there are more busbars, each one is made much thinner. The total amount of area on the cell covered by silver (which blocks sunlight) is reduced. This means more active silicon area is exposed to light.

2). Improved Reliability and Durability

Lower Mechanical Stress: The tabbing wires (ribbons) that connect the cells are also made thinner. Thinner ribbons are more flexible, which reduces the stress on the cell during thermal expansion and contraction (from daily heating/cooling cycles). This lowers the risk of micro-cracks.
Better Performance with Micro-Cracks: If a micro-crack does occur, it is less likely to completely isolate a section of the cell because there are more busbars providing alternative paths for the current to flow. This helps maintain the module’s power output over its lifetime.

3). Cost-Effectiveness

While using 12 busbars requires more precise manufacturing, it often uses less silver overall. Silver is a significant cost driver in solar cell production. By using finer lines, manufacturers save on material costs while boosting performance.

4. Comparison Table: BB Evolution

Feature	Traditional (e.g., 5BB)	Advanced (12BB)	Benefit of 12BB
Number of Busbars	Fewer (e.g., 5)	More (12)	Shorter current path, less resistance
Busbar Width	Thicker	Thinner & Finer	Less shading, more light capture
Tabbing Ribbon	Thicker	Thinner & More Flexible	Reduced risk of micro-cracks
Efficiency	Lower	Higher	More power from the same size cell/roof
Reliability	Standard	Improved	Better long-term performance and durability

Conclusion

12BB solar cells represent a key incremental innovation in photovoltaic technology. They are not a fundamentally new type of cell (like PERC or HJT), but rather an optimization of the electrical grid design on mainstream cell types.

This design shift is a major reason why the power ratings of solar panels have been steadily increasing over the past few years, with many premium residential and commercial panels now utilizing 12BB or even higher busbar count cells (like 16BB) to achieve higher efficiencies and better reliability.

In short: 12BB cells are a more refined, efficient, and robust version of the standard silicon solar cell, leading to better-performing and longer-lasting solar panels.

Posted by Carrie Wong / WSL Solar
WSL Solar has been a quality and professional manufacturer of custom solar panels, solar mini panels, IoT solar panels and solar solution provider in China since 2006.
https://www.wsl-solar.com

Manufacturer of Custom Solar Panels – WSL Solar

WSL Solar has been a quality and professional manufacturer of custom solar panels and solar solution provider in China since 2006.

With our in-house R&D team and management team for over 20 years’ experience in solar industry, we can design and develop a customized solar panel in a variety of sizes, shapes and outputs to meet our client’s specific requirement, and provide solution support start from initial product development stage.

Our product categories include tempered glass solar panels, ETFE solar panels, and amorphous solar panels.

Welcome to contact us for high quality custom solar panels.

Email: info@wsl-solar.com

https://www.wsl-solar.com