Detailed Solar Panel Raw Material List for Quality Panels

The discovery of the photovoltaic effect in 1839 by Edmond Becquerel laid the foundation for solar technology. However, significant advancements — including the development of silicon solar cells (a core solar panel raw material) in the 1950s — have paved the way for the widespread adoption of solar energy in the modern era.

Since then, solar energy has become cheaper while PV panels have become more efficient, lighter, and much improved in look — which has prompted a surge in demand for solar. The global solar power market is anticipated to experience substantial growth between 2021 and 2029, with estimates suggesting an increase of around 123% by 2029.

But what is in a PV module and how is it made? In this article, we look at solar panel raw materials that used to make solar panels. We look at the raw materials of a PV module including busbars, and junction boxes to the cell itself.

What Is A Solar PV Module And Its Components

A solar, or photovoltaic (PV) module as it is also called, is a device that converts sunlight into electricity. It is the key component of a solar energy system.

Solar panels convert sunlight into direct current (DC) electricity. This DC electricity is then directed to an inverter, which converts it into alternating current (AC) electricity compatible with most appliances and the power grid.

A PV module consists of several components which include:

1. Solar cells
2. Busbars
3. Encapsulant
4. A backsheet
5. A frame
6. A glass
7. A junction box

These components are assembled in a solar panel manufacturing process that involves several steps and machines. There are several machines used in renewable energy production or solar production. They each complete a step in the process of manufacturing a solar module.

For example, stringers connect the solar cells together; foil cutters cut and place the backsheet onto the module while framers place the module inside a frame. For a complete review, read our article on solar panel machines.

Solar Cells

PV panels are the most important part of solar energy systems. Equally, solar cells are the most important component of a PV panel. They are responsible for capturing the energy from the sun and converting it into usable electricity.

A solar module consists of multiple solar cells, typically 60 or 72, wired together. A solar cell is made from a thin wafer of silicon. Each cell is connected to the other cells in the module by thin wires known as busbars.

Solar cells are the most expensive part of a solar panel. The quality of solar cells varies depending on the material it is made from. Silicon cells are generally more expensive than thin-film cells. While they cost more, they are more efficient. This is the main reason why most solar panel production focuses on silicon panels. 90% of solar PV panels in production on the market are silicon.

Busbars

Busbars are thin, conductive strips, typically made of copper or aluminum, that collect and distribute electric current generated by individual solar cells within a module. They are positioned on the surface of the cells and connect them electrically to form a circuit. The number of busbars can vary depending on the cell design and desired efficiency. While increasing the number of busbars generally reduces resistance and improves current collection, it can also slightly decrease the light-receiving area, affecting overall power generation. Additionally, newer technologies like multi-busbar cells and busbarless designs are being explored to further optimize efficiency and address other considerations.

Glass

Solar PV modules need to be protected from environmental factors such as moisture, dirt, and physical impacts while allowing sunlight to be absorbed by the solar cells. This is where the glass comes in.

Modules do not use ordinary glass; solar cells are protected by tempered glass — which is 3.2mm thick and up to six times stronger and more durable than regular glass. 

The glass is also treated with an anti-reflective coating to reduce reflections and increase the amount of sunlight reaching the solar cells.

The primary purpose of solar panel glass is to transmit as much sunlight as possible into the module while ensuring a high solar radiance transmittance and a low reflection rate. 

Back Sheet

The backsheet is located on the back of the module. It is typically made of a multilayer polymer material like polyvinyl fluoride (PVF) or ethylene-tetrafluoroethylene (ETFE). The backsheet can also help in providing insulation, which helps to prevent electric shocks and short circuits.

The primary purpose of the backsheet is to protect the solar cells and other components of the module from moisture, dirt, and other environmental factors. This lengthens the lifespan of the module and maintains its performance over time.

The backsheet can also help to reflect light back onto the solar cells, increasing the module’s efficiency.

Encapsulant (EVA)

The encapsulant is a thin layer of polymer material applied to both the front and back of solar cells within a module. It serves several critical functions:

Protection: It safeguards the cells from environmental factors like moisture, dirt, and other external elements.

Mechanical support: It provides structural support for the cells, holding them in place and preventing physical damage or movement.

Electrical insulation: It helps to electrically insulate the cells and other components within the module.

Light transmission: It is designed to allow optimal light transmission through to the solar cells, minimizing any potential absorption or blocking.

Frame

The frame of a solar module holds all of the other components together and gives the module its structure. It is usually made of aluminum or stainless steel and wraps around the edges of the module.

The frame also provides a convenient place to mount the module, as well as a way to secure the other components.

Junction Box

The junction box is a small box at the back of the module that houses the electrical connections between the solar cells and the external circuit. It is usually made of plastic or metal and is designed to protect electrical connections from moisture and dust.

The junction box connects the module to the rest of the solar power system.

Conclusion

From the solar cells and busbars to the junction box and frame, each part plays an important role in the overall performance of the module.

Quality materials ensure you produce good quality solar panels. Faulty solar cells or busbars can increase the internal resistance of the solar module and cause it to heat up. This can create a potential safety hazard.

Poor-quality encapsulants, backsheets, or frames will wear away easily and allow moisture to seep into the module and damage the solar cells. A faulty junction box or connectors will reduce the output of the solar module.

This is why it’s critical for manufacturers to find good suppliers of raw materials. Module manufacturing is increasingly becoming a very competitive industry. Companies that want to compete at the highest levels are the ones that will consistently produce good quality products and the first step to achieving this is sourcing quality materials.