Solar Panels

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.