How does a double-sided double-glass n-type monocrystalline solar photovoltaic module "capture" reflected light from the ground to increase power generation?
Publish Time: 2025-08-25
As photovoltaic technology continues to pursue higher efficiency and lower cost per kilowatt-hour, the double-sided double-glass n-type monocrystalline solar photovoltaic module, with its superior power generation performance and long-term reliability, has become a mainstream choice for large-scale ground-mounted power plants, industrial and commercial rooftops, and specialized applications. One of its most notable technical highlights is its "bifacial" power generation capability—not only does it absorb direct sunlight on the front side, but it can also "capture" reflected light from the ground on the back side, significantly increasing power generation.1. Bifacial Power Generation Principle: The Secret of Backside Power GenerationConventional photovoltaic modules only generate power from the front side; the back side has an opaque backsheet, making it unable to utilize light from below. Bifacial double-glass modules, on the other hand, utilize a double layer of tempered glass. Instead of an insulating backsheet, the back side is covered with a transparent or semi-transparent glass layer, allowing sunlight to penetrate the module and reach the n-type solar cells on the back side. N-type monocrystalline cells inherently possess the bifacial property of receiving light and generating electricity. Their structural design allows both sides to absorb photons and generate current simultaneously. When sunlight strikes the ground (such as the ground, rooftops, snow, sand, etc.), it is reflected. This previously wasted "reflected light" is received by the back of the module and converted into additional electricity, thus achieving "bifacial gain." Experimental data shows that under ideal conditions, the power generation gain of bifacial modules can reach 10% to 25% or even higher, significantly improving the power generation efficiency per unit area.2. N-type Cells: The Dual Advantages of High Efficiency and Low AttenuationThe performance of bifacial power generation is inseparable from the support of high-efficiency cell technology. Compared with traditional P-type PERC cells, N-type monocrystalline cells (such as TOPCon and HJT) have higher conversion efficiency (generally exceeding 24%), lower light-induced degradation (LID), and a lower temperature coefficient. More importantly, N-type cells are more sensitive to long-wavelength light (such as diffuse light reflected from the ground), maintaining high power generation capacity even in low or scattered light environments. This allows the reflected light received on the rear side to be effectively converted into electricity even in the early morning, evening, or on cloudy days, further amplifying the bifacial gain.3. Installation Method and System Design: Key to Optimizing Bifacial GainTo fully leverage the advantages of bifacial solar panels, the installation method and system design of the modules are crucial:Mounting Height: The higher the modules are above the ground, the more evenly reflected light is received on the rear side, minimizing shading. A height of at least 1.5 meters above the ground is generally recommended.Mounting Structure: Use non-metallic or narrow-framed mounting brackets to minimize backlight obstruction.String Spacing: Optimize the spacing between front and back rows to avoid shadows on the rear side while ensuring proper ventilation and heat dissipation.Tilt Angle Optimization: Adjust the module tilt angle based on the geographic location and reflective surface characteristics to balance light received on the front and back sides.In addition, using a dedicated bifacial inverter and monitoring system allows for more accurate assessment of bifacial gain, enabling refined operations and maintenance management.4. Double-Glass Structure: Providing Reliable Guarantee for Bifacial Power GenerationThe long-term, stable operation of bifacial modules is due to their double-layer tempered glass encapsulation. Compared to traditional backsheet modules, the double-glass design offers enhanced:Weather resistance: UV resistance, humidity and heat resistance, and salt spray corrosion resistance, making it suitable for high-humidity, high-salt, and highly polluted environments;Mechanical strength: Enhanced resistance to wind pressure and hail impact;Preventing hidden cracks: The rigid glass support reduces stress on the cell, reducing the risk of hidden cracks;Zero water permeability: Eliminates PID (potential-induced degradation), extending the service life to over 30 years.These features provide the long-term, stable physical foundation for bifacial power generation, ensuring the continued effectiveness of the backside power generation throughout its lifecycle.The double-sided, double-glass n-type monocrystalline solar photovoltaic module achieves a technological leap from "unidirectional" power generation to "three-dimensional" power generation by absorbing direct light on the front side and capturing reflected light on the back side. This not only improves power generation efficiency per unit area but also reduces the cost per kilowatt-hour of photovoltaic systems, driving clean energy towards higher efficiency.
