What Are HJT Solar Panels

Heterojunction (HJT) solar panels, also known as Silicon Heterojunction (SHJ) or Heterojunction with Intrinsic Thin Layer (HIT) solar panels, are composed of advanced HJT solar cells that combine crystalline silicon with thin-film technologies. These cells are built on an N-type monocrystalline silicon substrate, with intrinsic amorphous silicon (i-a-Si

) layers deposited on its surface. This unique structure enhances the overall performance and efficiency of the solar cells, which are then assembled into panels for practical energy generation.

Key components of HJT cells include:

N-type Monocrystalline Silicon Substrate: The foundation of the HJT panel is an N-type silicon wafer. This type of silicon, with electrons as majority carriers, offers higher carrier mobility and lower susceptibility to light-induced degradation (LID).

Intrinsic Amorphous Silicon Layer: Both sides of the N-type silicon wafer are coated with an intrinsic (undoped) amorphous silicon layer, which acts as a passivation layer. This helps reduce surface defects on the silicon, lowering the recombination of charge carriers and improving cell efficiency.

Doped Amorphous Silicon Layers: P-type and N-type doped amorphous silicon layers are added on the outside of the intrinsic layers. These layers alter the material's conductivity and create a P-N junction, which is essential for generating electrical power.

Transparent Conductive Oxide (TCO) Layer: A thin coating of a transparent conductive oxide, such as Indium Tin Oxide (ITO), is applied to the surface to ensure high light transmission and good electrical conductivity.

Metal Electrodes: Metal electrodes are placed on the top and bottom of the cell to extract electrical current. These are made as thin as possible to minimize the shading effect and allow more sunlight to reach the cell surface.

Advantages of HJT Solar Cell Technology

210mm High-Efficiency Cells

HJT solar cells use 210mm high-efficiency cells, leveraging a Transparent Conductive Oxide (TCO) film that effectively passivates defects at the interface between crystalline silicon and doped amorphous silicon. This leads to a photoelectric conversion efficiency of 25%. The design features more numerous and finer busbars, which reduce shading and shorten the current transmission path. This results in lower resistance, improved current collection, and overall higher power generation efficiency. Additionally, the use of ultra-fine busbars reduces the risk of micro-cracks and busbar breakage, enhancing the cells' flexibility and reliability.

High Bifacial Rate

HJT solar cells have a symmetrical design on both the front and rear, combined with mesh plates, significantly boosting their bifacial generation capabilities. These cells can achieve over 95% power generation efficiency from the rear side, greatly enhancing overall energy output. The transparent dual-glass structure allows light to pass through the gaps between cells, further increasing rear-side power generation. This design is ideal for applications like carports, fences, and canopies, where dual-sided energy production is crucial. HJT cells outperform PERC and TopCon technologies by generating over 30% more power, making them highly effective in installations exposed to sunlight on both sides.

Excellent Low-Light Performance

HJT cells incorporate i-a-Si:H thin films between crystalline and doped amorphous silicon, with the undoped hydrogenated amorphous silicon layer (i-a-Si:H) passivating surface defects on the crystalline silicon. This process reduces charge carrier recombination, resulting in a high open-circuit voltage (Voc) of up to 750mV. The elevated Voc allows the cells to perform well in low-light conditions, achieving the inverter’s startup voltage more quickly and extending energy production during early morning and evening hours, maximizing daily energy yield.

Technical Advantages of HJT Compared to PERC and TOPCon

When comparing Heterojunction Technology (HJT), Tunnel Oxide Passivated Contact (TOPCon), and Passivated Emitter Rear Cell (PERC) solar panels, HJT offers several key technical advantages:

Bifacial Efficiency: HJT panels lead in bifacial efficiency with 95%, significantly higher than TOPCon at 85% and PERC at 70%. This means HJT panels capture more sunlight from both sides, maximizing energy generation.

Power Generation Efficiency: HJT panels achieve a power generation efficiency of 22.87%, outpacing TOPCon at 22.28% and PERC at 21.2%. This demonstrates HJT’s superior ability to convert sunlight into electricity, resulting in better overall performance.

Lower First-Year Degradation: HJT panels experience only 1% power degradation in the first year, compared to 1.5% for TOPCon and 2% for PERC. This makes HJT technology more stable and reliable in its initial years of operation.

Long-Term Stability: From the second year onward, HJT panels show an annual power degradation rate of just 0.35%, lower than TOPCon’s 0.4% and PERC’s 0.45%. This superior long-term performance ensures higher efficiency retention over time.

Temperature Coefficient: HJT panels have a lower temperature coefficient of -0.243%/°C, meaning they are less affected by temperature fluctuations compared to TOPCon (-0.32%/°C) and PERC (-0.35%/°C). This allows HJT panels to maintain more consistent performance in various environmental conditions.

Why choose us

Beijing Shan Hu International Technology Co.,Ltd. is a professional enterprise involved in manufacturing and marketing the best quality solar panels and provide solutions for a wide range and variety of customers home and abroad. It is located in Beijing Economic-Technological Development Area, China.

The company was established in 2020, now over 80% of our commercial managers and engineers have many years of solution experiences. At present, the company's business scope covers multiple countries and regions including China, Europe, America, Southeast Asia, and Africa. Beijing Shanhu International has always adhered to the mission of promoting the energy revolution process with photovoltaic technology and benefiting all mankind with solar energy. Aiming to create a series of digital comprehensive solutions for green energy, including green buildings, green travel, green industrialization, and smart home energy. We hope that through our exploration and efforts, more people can enjoy the value of sunshine and create a green energy world with the radiance of the sun.