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1. Core structure and working principle
Photovoltaic effect: When sunlight shines on semiconductor materials (such as silicon), photon energy is absorbed, stimulating electron transitions, forming an electric potential difference, and thus generating direct current.
Basic unit: A single solar cell (usually 6×6 inches) has an output voltage of about 0.5V, which is connected in series/parallel to form a solar panel (such as 18V or 36V panel), and then multiple panels are used to form an array.
2. Main types
(1) Classification by material
Monocrystalline silicon
High efficiency (15%~22%), long life (more than 25 years), but high cost.
Appearance is dark blue with rounded edges.
Polycrystalline silicon
Low efficiency (13%~16%), moderate cost, appearance is blue fragments.
Thin-Film
Flexible, light and thin, low cost, but low efficiency (10%~13%), often used in large power stations or curved surface installations.
Emerging technologies: perovskite, organic solar cells, etc. (laboratory efficiency exceeds 25%, but stability needs to be improved).
(2) By application scenario
Rooftop household type: power is usually 300W~400W/piece, used with inverter.
Industrial large panels: power can reach more than 500W, used in photovoltaic power stations.
Portable: foldable or small panels, used for camping and outdoor charging.
3. Key performance parameters
Conversion efficiency: Currently, the efficiency of commercial panels is generally between 15% and 22%.
Power output: rated power under standard conditions (AM1.5, 25°C, 1000W/m² illumination) (such as 300W/piece).
Temperature coefficient: high temperature will cause efficiency to decrease (about -0.3%~-0.5%/°C).
Durability: usually 25 years warranty, actual life can reach 30 years.
4. System composition
Solar panel: power generation unit.
Inverter: Converts direct current (DC) to alternating current (AC).
Energy storage battery (optional): Such as lithium-ion batteries, used to store excess power.
Mount and tracking system: Fixed or automatic tracking of sunlight to improve efficiency.
