Introduction to Solar Cells
Solar cells, also known as photovoltaic cells, are made from silicon, a semi-conductive material. Silicon is sliced into thin disks, polished to remove any damage from the cutting process, and coated with an anti-reflective layer, typically silicon nitride. After coating, the cells are exposed to light and electricity is produced.
Solar Photovoltaic Cell Basics
When we talk about solar cells, what we are actually referring to is a large family of materials known as photovoltaics. So, if you’ve ever wondered “how are solar cells made?”, it’s important to understand that not all solar cells are created equal. Let’s delve into the world of photovoltaics.
Silicon Solar Cells
Silicon solar cells are by far the most common type of solar cell used in the market today, accounting for about 90% of the global solar cell market. Their popularity stems from the well-established manufacturing process, which I’ve dedicated a considerable amount of my 20-year career studying and improving.
The Process of Creating Silicon Solar Cells
Creating a silicon solar cell is an intricate process that requires precision and care. Silicon, which is commonly found in sand, must be purified until it’s almost completely clean. This highly purified silicon is then used to grow a silicon crystal, which is subsequently cut into thin wafers. The silicon wafer is then “doped” with phosphorous and boron to create an electric field. An anti-reflective coating is then applied to the wafer to enhance light absorption.
Thin-film technologies are the second-largest category of photovoltaics. Unlike silicon cells, thin-film cells are manufactured by depositing multiple thin layers of photovoltaic material onto a substrate. They are cheaper and easier to mass-produce but typically have lower efficiencies than silicon-based cells.
The Process of Creating Thin-Film Photovoltaics
Creating a thin-film photovoltaic cell involves depositing one or more thin layers, or thin film (TF) of photovoltaic material on glass, plastic or metal. Depending on the choice of material, thin-film cells can be divided into several types, including Copper Indium Gallium Diselenide (CIGS) and Cadmium Telluride (CdTe).
Copper Indium Gallium Diselenide (CIGS) Solar Cells
CIGS solar cells deliver some of the highest efficiencies among thin-film cells. The process of making them involves the deposition of copper, indium, gallium, and selenium.
The Process of Creating CIGS Solar Cells
The thin films of CIGS are complex to manufacture. The raw materials are first evaporated in vacuum chambers. These vapors then condense on a glass or plastic substrate, forming a thin film. Getting the balance of materials right is a delicate process that can impact the efficiency of the cell.
Cadmium Telluride (CdTe) Solar Cells
CdTe solar cells are another type of thin film solar cell that has received considerable attention due to their potential for low-cost production.
The Process of Creating CdTe Solar Cells
To create CdTe solar cells, cadmium and tellurium are vapor deposited onto a substrate, similar to the process used for CIGS cells.
Perovskite photovoltaic cells are a newer entrant to the field of solar energy. They come with the promise of extremely high efficiencies and low production costs.
The Process of Creating Perovskite Photovoltaics
Perovskites cells are made by depositing layers of perovskite crystals (a type of calcium titanium oxide mineral) onto a substrate. It’s a precise, complex process still being fine-tuned by researchers and is seen as a very promising technology for the future of solar energy.
Continued exploration awaits in the solar panel manufacturing process. As we traverse this enlightening pathway together, I invite you to delve deeper into how different types of photovoltaics are developed. Stay tuned, as the journey is as captivating as the destination itself.
Solar Photovoltaic Manufacturing Basics
With the understanding of different types of solar cells, let’s get into the intricacies of solar photovoltaic manufacturing.
PV Module Manufacturing
Solar panels or PV modules are made by assembling solar cells into a frame that protects them from the environment. A typical PV module consists of a layer of protective glass, a layer of cells and a backsheet for insulation.
Silicon PV Module Manufacturing
In silicon PV module manufacturing, individual silicon solar cells are soldered together, typically in a 6×10 configuration. This assembly is then laminated to protect the cells from environmental degradation. They complete the panel by adding a frame and junction box.
Thin Film PV Module Manufacturing
In thin-film PV module manufacturing, the entire batch of films is deposited onto large glass panels. This panel is then cut into smaller sizes, and metal contacts are added. The entire module is then encapsulated to protect it from the elements.
Racking Systems for Solar Installations
The success of a solar installation doesn’t just lie with the quality of the solar panels. Racking systems that hold the panels in place are an equally important part of the equation. They need to withstand the elements while placing the panels at an angle that optimizes sunlight exposure.
Power Electronics in Solar Photovoltaic Systems
Once our magical solar panel is generating electricity, we need to ensure the electrical output matches our needs. That’s where power electronic devices, such as inverters, come in, transforming the direct current (DC) produced by the panel into the alternating current (AC) used in most homes.
From Sand to Modules: The Journey of Solar Panel Creation
Let’s connect the dots from sand to solar modules.
The Process of Turning Sand into Silicon
Most people don’t realize that the sandy beaches they laze on during summer vacations have a direct link to the solar panels adorning rooftops. The production journey of a silicon solar cell begins with sand, or to be precise, quartz. After extraction, the quartz is then heated in a furnace with carbon to produce metallurgical grade silicon.
How Silicon Becomes a Solar Cell
This silicon is then purified further and melted down before being formed into a large crystal – a process known as Czochralski process. This crystal is then precisely sliced into very thin wafers, each with the potential to become a solar cell.
Creating the Photovoltaic Module
From here, the wafers get treated with thermal processes and doped with specific elements to create a material where light can free electrons and produce electricity. These wafers are then soldered together and encased in a protective environment to form a photovoltaic module.
Implementing the Racking System
Once the module is ready, it’s mounted on a racking system, a structure designed to hold the module at the best angle to capture sunlight.
Incorporating Power Electronics
Lastly, power electronics ensure that the generated electricity can be either used immediately, fed into the grid, or stored for later use.
The Future of Solar Panel Manufacturing
With increasing efficiency and falling costs, the future of solar panel manufacturing looks bright.
How Advances in Technology are Affecting Production
Technology has significantly influenced how solar cells are manufactured. As we move forward, expect to see more sophisticated manufacturing techniques that yield greater efficiencies. From the use of machine learning to optimize cell production to the rise of new materials with superior light-capturing capacities.
Environmental Impact and Sustainability Efforts
While the ultimate aim of solar is to provide cleaner energy, the process itself must also be sustainable and eco-friendly. Increased recycling and reduced waste are becoming significant parts of the manufacturing process. But, our job is not done yet. The industry continuously seeks ways to reduce energy expenditure in production and shift to greener processes.
Research and Development in Solar Panel Production
With time, the question “how are solar cells made?” continues to adopt new answers. Research and development are the backbone of the evolution we see in solar cell manufacturing. As we move forward, we can expect solar technology to continue to improve whilst becoming more accessible than ever before. And you better believe that I’ll be there, watching every step of this unprecedented evolution unfold.