Polycrystalline silicon solar panels, also known as multicrystalline silicon solar panels, are composed of various materials and components that work together to convert sunlight into electricity. These solar panels are a popular choice for residential and commercial solar installations.

1. Silicon Wafers: Polycrystalline silicon solar panels are made using silicon wafers. These wafers are created by melting raw silicon and then cooling it into ingots. The ingots are then sliced into thin wafers. Unlike monocrystalline solar panels that use single-crystal silicon, polycrystalline panels use silicon fragments melted together, resulting in a less uniform crystal structure.
2. Backsheet: The backsheet is the bottom layer of the solar panel that protects the panel from environmental factors such as moisture and heat. It is typically made of a polymer or a combination of polymers that provide electrical insulation and protection from UV radiation.
3. Encapsulant: The encapsulant is a layer that sits between the top layer of glass and the solar cells. It is typically made of ethylene-vinyl acetate (EVA) and serves to protect the solar cells from various environmental factors and provide electrical insulation.
4. Glass: The top layer of the solar panel is usually made of tempered glass that protects the solar cells from impact and weather conditions while allowing sunlight to pass through.
5. Frame: The frame provides structural support to the solar panel, protecting it from mechanical stress and ensuring its durability during installation and operation.
6. Junction Box: The junction box is an important component located on the back of the solar panel. It is responsible for housing the electrical connections and protecting them from environmental damage. The junction box also allows for the connection of multiple solar panels in an array.
7. Busbars and Conductive Layers: These are the conductive pathways on the solar cells that collect the generated electricity and transfer it to the junction box for further distribution.

Each of these components plays a crucial role in the overall performance and durability of polycrystalline silicon solar panels. When exposed to sunlight, these panels generate direct current (DC) electricity, which can be converted into alternating current (AC) using an inverter for consumption in homes or businesses.