Solar cells and solar panels are both integral, and closely related, parts of a solar energy system. When reading about solar energy systems, it may seem as if these titles are almost interchangeable. Writers refer to them both when discussing energy production and output, and often do so without explanation of how these parts work. However, each plays a distinct role. Solar cells contain all the parts necessary to convert sunlight to electricity. Solar panels combine and direct all of that energy output.
The photovoltaic system
Solar panel systems are referred to as photovoltaic systems in the solar industry. This differentiates them from other solar technologies, such as solar thermal and concentrated solar power. Photovoltaic systems have several parts and each plays a distinct role.
The entire system begins with the solar cells. These cells are where sunlight is actually used to produce electricity. Solar panels are a combination of multiple solar cells. These cells are arranged in such a way that the solar panels can capture and combine the electrical output of each solar cell and send it along a specified path. Once the solar panels have captured the electricity, they send it all to an inverter which converts the DC electricity created by the cells to the AC electricity you use in your home. After this, the electricity is sent through your meter and into your home. All of the parts in a photovoltaic system have distinct roles, but each is so dependent on the other parts that it is easy to confuse them.
The role of solar cells
Solar cells produce electricity through a natural reaction called the photovoltaic effect. This is where the system gets its name. The basic premise of the photovoltaic effect is that sunlight creates electricity in certain materials by knocking their outer electrons loose.
There are multiple layers within solar cells. The most important elements are the two semiconductors in the center. The top semiconductor is a negative layer, which means the material’s atoms contain extra electrons. These electrons are energized by sunlight and the extra electrons are knocked loose. The bottom semiconductor is a positive layer. This material’s atoms have space for more electrons. When electrons are knocked off the negative layer they are attracted to the positive layer. A barrier is formed between them. Negative conductors on top of the cell and positive conductors on bottom force the electrons to travel around the cell in a specific direction. This creates the electrical current you will use. The conductors force the current out of the cell and into an electrical load, which captures the energy. The electrons then continue their path until they re-enter the cell and connect with the positive layer. This completes the circuit and allows the process to continue. The entire purpose of the solar cell is to ensure this process flows unimpeded so that you get as much electricity as possible.
The role of solar panels
The solar panel’s role is to amplify, protect and direct electricity. Solar cells can produce only a limited amount of energy. When building a solar energy system, multiple solar cells are connected in series or parallel circuits to create a solar module. This produces higher currents and more energy. The modules also seal all of the solar cells and wiring in a protective case to guard it from the weather. These modules are then wired together as a solar panel. It is important to note that a solar panel may consist of just one module or multiple, meaning modules and panels are sometimes used interchangeably. These solar panels are pre-wired and ready to be installed on your rooftop.
By connecting all of these parts into solar panels, the resulting electricity has a more precise path to follow. When the electrical current leaves the solar cells to travel through the electrical load, it is captured by the load and sent through the solar panels. The method by which the solar cells are wired together determines how the electrical current will flow through the solar panels. Whichever way it flows, it will direct the electricity from all the solar cells together. All the electricity will then be directed out of the solar panels and toward the inverter, where the rest of the photovoltaic process is completed.
Solar cells and solar panels work together to produce the electricity you need for your home. Although they are closely related, with the solar panels actually containing the solar cells, each plays its own part. Considered as one, the entire photovoltaic system works like an assembly line. Every part performs its job alone, and then passes its product on to the next part. Each product is necessary for the next section to do its job. Only the solar cells can perform alone, but its products are useless without the rest of the system. Your entire solar energy system is a clean and quiet production line working to create electricity for you in a natural and efficient way.
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