When I initially became interested in solar energy, I was confused about the link between solar panels and solar or photovoltaic cells. Solar panels and cells are two distinct components of your solar PV system, even though they are sometimes interchangeable. That said, what are the important differences between the two?
Solar cells are the smallest functional unit or the building element of an electrical generator that uses solar energy as its input energy and converts it to electricity. On the other hand, a solar panel is a group of solar cells that use the photovoltaic effect to create electrical energy directly from solar energy.
Photovoltaic cells (solar cells) are electrically coupled in series and parallel circuits to produce higher voltages, currents, and power levels. In light of that, it’s important to know exactly how they form into larger units and how a solar cell forms into a solar module, panel, and finally, a solar array. So, how does it work?
Solar Cell Vs. Solar Panel: Different Roles
In short, a solar cell panel is made up of numerous solar cells. The dimensions of a solar cell are obtained by cutting wafers from an ingot (usually a silicon ingot) in conventional wafer sizes.
A solar cell has a very high sunlight-active area compared to its entire area, which is only reduced by electrical wires. A solar cell panel has a lower solar-active area than a single solar cell (it is due to the space and areas between the solar cells).
As a result, it is vital to pay attention to what solar cell efficiencies are given, such as solar cell efficiency for a single solar cell or solar cell efficiency for a solar cell panel.
In addition, the solar cell efficiency will be higher per cell than per panel (because the panel has a smaller solar-active area than the total area of a single cell), which is rarely stated.
Individual solar cells and solar cell panels are electrically connected through parallel and serial connections.
Also, keep in mind that the titles, such as solar cell, solar panel, and solar cell panel, are frequently used in a broad sense that does not always correspond to their exact or rigorous meanings.
I try to avoid the phrase solar panel since it is unclear and may be misconstrued, as a solar panel is a catch-all term for both a solar cell and thermal panels. Photovoltaic (PV) solar panels (or photovoltaic solar cell panels) and thermal solar panels are frequently used.
In addition, the words building-integrated photovoltaics (BIPV) and building applied (added, attached) photovoltaics are used (BAPV). With that said, let’s take a closer look at the roles of photovoltaic cells and thermal solar panels.
The Role Of Photovoltaic Cells (Solar Cells)
To begin, we’ll look at photovoltaic cells and their purpose in your solar PV system. Your solar cells generate energy by the photovoltaic effect, which occurs when sunlight causes electricity to be generated in specific materials by knocking their outer electrons loose.
Without sounding gibberish, photovoltaic cells can be manufactured from monocrystalline or polycrystalline material and are made up of numerous layers. The most essential of these are the two semiconductors in the center.
The top semiconductor is a negative layer because the material’s atoms have additional electrons with a negative charge. On the other hand, the bottom semiconductor is a positive layer since the material’s atoms lack electrons.
When sunlight strikes the top semiconductor, the free electrons become excited, are knocked loose, and are subsequently drawn to the positive layer underneath as conductors on both levels drive electrons to move around the cell. An electric current forms a barrier between the two layers.
The conductors then drive this current out of the cell and into an electrical load, capturing the energy produced by your solar cell. The electrons finally re-enter the cell, and the cycle begins again.
The Role Of Thermal Solar Panels
Because photovoltaic cells only produce a certain quantity of electricity, a solar panel comprises several joined cells. When several solar cells work together, they create greater currents and hence more energy.
Furthermore, by enclosing many cells, your panel serves as a safe shell for the cells to dwell in. It implies that your solar cells are less vulnerable to external forces such as hail damage.
The direct current (DC) power generated by your solar panels is then routed to your central inverter (or micro inverter, depending on your system configuration), where it is transformed into alternating current (AC) electricity that your house and appliances can utilize.
The sum of cells in your panel will vary depending on the brand and size you select, but 60 to 72 cells in a single panel are usual. Another phrase you may have heard is the photovoltaic array, which refers to a system made up of many PV panels.
An Overview Of The Photovoltaic System
A solar photovoltaic panel or module comprises several solar cells arranged in an integrated group and all orientated in the same plane. On the sun-facing side of photovoltaic modules, a pane of glass allows light to flow while safeguarding the semiconductor wafers.
Solar cells are often coupled in series to provide additive voltage. A greater current is obtained by connecting cells in parallel.
However, issues with paralleled cells, such as shadows, can cause the weaker (less illuminated) parallel string (a series of series-connected cells) to shut down. It results in significant power loss and potential damage due to their illuminated partners’ reverse bias applied to the shadowed cells
Interconnecting modules can create arrays with a different peak DC voltages and loading current capacities. It can be achieved with or without the use of independent MPPTs (maximum power point trackers) or, depending on the module, with or without modules such as microinverters or DC-DC optimizers.
Shunt diodes can reduce shadowing power loss in arrays with series/parallel connected cells.
In summary, solar PV systems rely on both photovoltaic panels and cells. Photovoltaic cells are the primary component of a solar panel, and solar panels are an important component of a solar system.
While a single solar cell may convert sunlight into electricity, the panel is required to combine and send the energy production of many cells to your inverter and house.
Because a solar panel has a smaller solar-active area than a solar cell, the solar cell efficiency will always be higher per cell than per thermal solar panel. It is always great to understand the materials of the photovoltaic system and how each unit plays a combined yet individual role.