Solar panels — also called Photovoltaic Panels (PV Modules) — convert sunlight into electrical energy.
When photons (light particles) hit the solar cell surface, they make electrons move and jump between poles, creating voltage and current.
So, any system that generates voltage from light can be called a photovoltaic system.
Today, most panels used in the market are crystalline type modules, mainly monocrystalline panels.
The difference between polycrystalline and monocrystalline is only in the structure of the cells, not the general panel design.
As shown above, solar panels are made by connecting many small solar cells in series.
These cells are made of semiconductor materials.
When a photon hits the negative side of a cell, it knocks an electron loose — that electron then travels toward the positive side through the external circuit (the connected cable).
The amount of electrons flowing per unit time forms the electric current (I = dQ/dt).
The stronger the light intensity, the more photons hit the surface, and therefore, the higher the current generated.
In the production process, cells are connected by thin conductive ribbons called busbars and ribbons.
Cells are connected as + - + - + - in series — usually 60 or 72 cells per panel.
Every 20 or 24 cells, a bypass diode (also called a bridge diode) is added to protect the circuit.
Bypass diodes are used to prevent power loss when part of a panel is shaded or when some cells are damaged.
If even one cell is shaded or faulty, it adds resistance to the circuit and can cause the entire panel to lose power or heat up.
Bypass diodes allow current to “bypass” the affected section, reducing risk and maintaining production.
The more bypass diodes a panel has, the lower the risk of power loss.
For example, in a 72-cell panel, 24 cells are under one diode; in a 60-cell panel, it’s 20 cells.
If every cell had its own bypass diode, panels would perform much better in shaded areas.
Yes. Panels use high-transparency tempered glass, which is both durable and impact-resistant.
Keeping the glass clean and using the correct cleaning methods is important for efficiency.
Low-quality glass reduces light transmission and lowers panel output.
EVA (Ethylene Vinyl Acetate) protects the cells inside the panel.
It prevents corrosion and air contact, forming a vacuum-sealed protective layer around the cells.
This extends the lifetime of the cells by keeping out air and moisture.
If EVA is applied poorly, panels may degrade quickly — even if they pass initial factory tests.
For example, just like a white T-shirt turns yellow in sunlight after a year or two, poor encapsulation leads to discoloration and aging in panels.
EVA should both protect the cells and allow maximum light transmission (ideally close to 100%).
High-quality EVA ensures long life for the entire panel.
Remember:
It’s not the cell that wears out quickly — it’s the materials around it (glass, EVA, backsheet) that determine panel life.
The backsheet is the protective layer on the back of the panel.
Its quality is also critical.
Since panels generate heat during operation, a weak or paper-like material can burn or deform.
If the material traps heat, it can reduce efficiency.
That’s why professional manufacturers use high-quality, heat-resistant backsheets.
The junction box contains bypass diodes and connection cables that allow panels to be linked together.
Each component in the BOM (Bill of Materials) is important —
poor-quality diodes or cables can cause panel failures or even fire hazards.
Every panel will generate energy when it leaves the factory.
However, true quality becomes clear after at least two years of operation.
Only then can long-term performance and reliability be confirmed.