Types of Commercial Solar Panels and their structures

In collaboration with ITE East, we had provided a series of commercially available solar panels for their in-house displays. Each display has a unique QR code that will direct the learner to sections below which will explain in more details the various solar panel properties and their applications in the real world.

In this article, we will explore specifically the following types:

PET Laminated Solar panel
Epoxy Resin Laminated Solar panel
Standard Glass Laminated Solar panel
Frameless Glass Laminated Solar panel
Back-contact semi-flexible Solar panel
Thin film glass laminated solar panel
Polycrystalline silicon solar cell

PET Laminated Solar panel

MATERIALS

PET (also known as Polyethylene terephalate) is a type of plastic which is commonly used for bottled water, takeaway containers and household products due to their material stability, wear resistant and non-toxic nature. It’s high transparency and good scratch resistant also makes it suitable as a protective layer above the solar cell. Solar cells used can be monocrystalline or polycrystalline.

This allows good sunlight absorption while keeping the solar panel lightweight (compared to glass laminated solar panels)

PET laminated solarpanel kmx xsection png

PROCESS:

The PET laminated solar panel is made by placing layers of PET, EVA, solar cell and PCB together. They are then laminated by machine at a temperature of 135 degrees Celcius which will melt the encapsulating materials together to form a watertight bond.

HIGHLIGHTS:

High clarity
UV resistant

Humidity resistant
Good scratch resistant

Consistent textured surface
Attractive appearance

How the back of a PET laminated solar panel PCB look like.

APPLICATIONS:

It is widely used on small plug-n-play outdoor solar LED lights, folding solar chargers, solar backpacks and other solar gadgets. It is usually used for low voltage and low power applications.

LIFESPAN: 3 year +

PET laminated foldable solar charger laptop

Epoxy Resin Laminated Solar panel

MATERIALS

Epoxy is a type of liquid resin known for its good adhesive properties and resistance to water degration. That is why they are used for laminating solar cells and is also used in boat building too. They are usually identified by their amber or slight brown colour. They also have high electrical insulation and good chemical resistance. However, in the long run, they can age prematurely under the Sun, turning yellowish and become more brittle.

epoxy laminated solarpanel kmx xsection png

PROCESS

When the solar cell is ready for encapsulation, it is placed on the backing material and the liquid epoxy resin is poured over the cells and the connecting ribbons. These layers will be laminated together at a temperature of 50 to 60 degrees Celcius and will form a harden layer when it cools.

HIGHLIGHTS:

High strength

Impact resistant
High electrical insulation

Economical
Attractive appearance

APPLICATIONS:

It is a low-cost product which has been traditionally used used for solar lights, solar toys, solar educational kits for kids and students in schools which has less demanding performance requirements. It is usually used for low voltage and low power applications.

LIFESPAN: 2 year +

Standard Glass Laminated Solar panel

MATERIALS

The common solar panel commercially available for industrial use has multiple layers sandwiched together. Clear protective EVA films are waterproof have clear clarity. They are placed above and below the solar cell. A low reflection, high clarity tempered glass cover is placed over the top for impact resistance. A backing combination called TPT (Tedlar-PET-Tedlar) gives support and gives the solar panel weather resistance. An aluminum frame is further added for additional structural strength.

PROCESS

The solar cell is placed between EVA films with the glass on top and then the TPT backsheet below everything. A high speed vacuum extracts any air trapped inside the layers and also ensure a good press before they are laminated and cured in an industrial oven at a temperature of 110 – 150 degree Celcius. The finished product has high strength, protection from moisture and should last for a long time

HIGHLIGHTS:

High strength

Impact resistant
Commercial grade

Long life span and durability
Attractive appearance

APPLICATIONS:

These are standard commercial solar panels used for anything from residential projects to large solar farms that power whole towns. They are suitable for stand-alone off-grid solar systems which have their own battery bank and also large grid-tied solar systems that is tied to the power grid to offset power usage.

LIFESPAN: 10 – 25+ years

Frameless Glass Laminated Solar panel

This is the same as the standard glass laminated solar panel except that no supporting frame is added to the compressed layers. This is to make it more lightweight, reduce cost and look aesthetically better in architectural designs. This is especially true for BIPV (Building Integrated PV) in green buildings which needs it to be part of the building facade. This is also commonly used for solar carports or thin-film solar modules in solar farms.

Back-contact semi-flexible Solar panel

MATERIALS

Using special manufacturing techniques on a monThe back of the back-contact solar cell has two metal grids. One collects the current from the n-type contact and the other contact collects the current from the p-type contact. SunPower commercialized back-contact solar cell modules with an initial achievement of 22.5% of efficiency. Now SunPower has achieved an efficiency of up to 24.2% from a monocrystalline silicon IBC solar cell. By using lighter and thinner PET or PVDF plastic as the front layer in place of the heavier tempered glass cover, the solar panel can flexible enough to be slightly bent and is also more portable.

backcontact flexible solarpanel kamtexsolar singapore

backcontact flexible solarpanel kmx xsection png

PROCESS

The fabrication of the back-contact laminated solar panel is similar to a standard laminated solar panel. The back-contact solar cells can be even placed closer together as there all the contacts are behind for easier connections. The thin PET / PVDF plastic sheet is laminated together with the other layers to form a very lightweight, high efficiency solar panel that is suitable for portable applications.

HIGHLIGHTS:

Very high efficiency

Expensive
Commercial grade

Long life span and durability
Attractive black appearance

APPLICATIONS:

The flexible back-contact solar panels are usually used on the curved surface on boats because they can be slightly bent without affecting its solar performance. They are also popular among campers, backpackers and hikers to power their equipment or recharge their mobile devices due to their lightweight and smaller size due to higher efficiency per cell area.

LIFESPAN: 6 year +

Thin film glass laminated Solar panel

MATERIALS

Thin film cells are produced using very little amount of silicon compared to crystalline solar panels. This means it can be very thin and can be applied as a film on various type of backing materials. For commercial use, they are usually laminated on glass for greater durability and lifespan. Thin film also has better low light performance and higher tolerance to the incident sunlight angle. However, they are traditionally much less efficient per area of solar module than crystalline solar panels. This means that they are usually not used in projects where space is limited.

PROCESS

The fabrication of the thin film solar panel is very different from mono- and polycrystalline solar panels. The thin layers of silicon is deposited directly on thin layers of plastic sheet or glass sheets.

HIGHLIGHTS: