What is N-TOPCon Photovoltaic Module Technology?
What is TOPCon Technology?
TOPCon (Tunnel Oxide Passivated Contact) technology is a revolutionary advancement in solar cell development, built on the principle of selective carrier transport. It enhances efficiency and performance by leveraging a specialized rear-side structure, which includes an ultra-thin silicon oxide layer and a lightly doped silicon layer. Together, these layers create a highly efficient passivated contact, significantly minimizing recombination losses at the surface and from metal contacts.
Unlike traditional PERC (Passivated Emitter and Rear Cell) technology, TOPCon offers superior photovoltaic conversion efficiency through its unique structural innovation. This next-generation solution reduces energy losses while delivering unmatched reliability. Its widespread adoption marks a transformative shift in the solar power industry, opening doors to greater efficiency and sustainable growth.
Working Principle and Structural Features of TOPCon Solar Cells
TOPCon solar cells stand out with their ultra-thin oxide layer (1-2 nm), which enables efficient tunneling of majority carriers. This design minimizes recombination of minority carriers, leading to significant improvements in open-circuit voltage and short-circuit current, while boosting overall efficiency.
The breakthrough lies in the rear passivated contact structure, a step beyond the conventional designs of N-type or N-PERT cells. This advanced configuration includes a silicon oxide layer and a phosphorus-doped silicon thin film. Under precise annealing at 850°C, the film transitions from a mixed-phase microcrystalline state to a polycrystalline structure. This process activates superior passivation, achieving an open-circuit voltage surpassing 710 mV and reducing recombination rates to an impressive 9-13 fA/cm².
By combining innovation with precision, TOPCon technology sets a new standard in the pursuit of high-efficiency solar cells.
Production Process of N-TOPCon Solar Cells
TOPCon solar cells are at the forefront of photovoltaic innovation, leveraging an ultra-thin oxide layer (1-2 nm) to enable efficient tunneling of majority carriers. This breakthrough minimizes minority carrier recombination, significantly enhancing open-circuit voltage and short-circuit current, which directly contributes to higher energy conversion efficiency.
The unique advantage of TOPCon technology lies in its advanced rear passivated contact structure. While the front design closely resembles traditional N-type or N-PERT cells, the rear incorporates an ultra-thin silicon oxide layer coupled with a phosphorus-doped microcrystalline-amorphous silicon film. During the annealing process at 850°C, the silicon film transforms from a microcrystalline-amorphous phase to a polycrystalline structure. This transformation activates exceptional passivation properties, enabling open-circuit voltages of over 710 mV and reducing electron recombination rates to an impressive 9-13 fA/cm². These advancements ensure superior performance in diverse solar energy applications.
One of the key benefits of TOPCon technology is its compatibility with existing P-type cell manufacturing processes. The production workflow integrates seamlessly with traditional methods, requiring only the addition of boron diffusion and thin-film deposition equipment. By eliminating complex steps such as backside opening and alignment, the process significantly reduces manufacturing complexity and enhances scalability for mass production.
With its ability to achieve high efficiency and maintain cost-effective production, TOPCon technology is poised to redefine standards in the photovoltaic industry. It not only offers a path to superior solar cell performance but also aligns with the growing demand for renewable energy solutions optimized for sustainability and scalability.
- Texturization (Texture): The silicon wafer surface is textured using physical or chemical methods to optimize light absorption by reducing reflection.
- Boron Diffusion (Diffusion LP-BBr₃): Low-pressure boron tribromide gas is utilized for P-Type boron diffusion, creating the emitter zone for efficient charge separation.
- Laser Selective Emitter: Laser technology modifies specific areas of the silicon wafer to form selective emitter regions, improving electrical performance.
- Chemical Edge Isolation: Excess material at the wafer edges is chemically removed to minimize surface defects and enhance durability.
- TOPCon Oxidation: An oxide layer is grown on the wafer surface for superior passivation, significantly reducing electron-hole recombination.
- TOPCon PECVD: A tunnel oxide layer and a polycrystalline silicon layer are deposited using PECVD technology, forming advanced passivated contacts.
- TOPCon High-Temperature Anneal: High-temperature annealing activates the passivation layers, further boosting cell efficiency by enhancing electrical properties.
- Alumina Deposition (Al₂O₃ front): An alumina layer is deposited on the front surface to improve passivation and stabilize the cell structure.
- Silicon Nitride Deposition (PECVD SiNx front & rear): Silicon nitride layers are deposited on both sides of the wafer for anti-reflection and additional passivation.
- Printing: Screen printing technology is employed to add metal electrodes on the wafer for electrical connectivity.
- Firing: Metal electrodes are bonded to the silicon wafer through high-temperature sintering, establishing robust electrical connections.
- Testing and Sorting: Cells are tested for performance and sorted based on efficiency to ensure consistent quality.
The TOPCon cell manufacturing process efficiently integrates with traditional P-Type cell production methods, requiring minimal modifications such as boron diffusion and thin-film deposition. It eliminates complex steps like backside opening and alignment, simplifying production while maintaining compatibility with PERC lines. The addition of the boron diffusion process and tunnel oxide + p-Poly layer ensures a seamless transition, making mass production cost-effective and scalable.
Comparison of N-TOPCon and PERC Technology
| TOPCON | PERC | |
|---|---|---|
| Appearance | Standard | Standard |
| First year power degradation | 1.5% | 2% |
| Average annual power degradation after the first year | 0.4% | 0.45% |
| Efficiency | 22.28% | 21.2% |
| Temperature coefficient | -0.32%/℃ | -0.35%/℃ |
Advantages of TOPCon Technology
High Conversion Efficiency: TOPCon cells achieve a mass production efficiency of 24.5%-25%, surpassing the average 23.2% efficiency of PERC cells. With a theoretical efficiency limit above 24.5%, TOPCon cells offer significant potential for further enhancement.
Enhanced Power Generation: The bifacial factor of TOPCon solar panels reaches up to 85%, notably higher than the 70% of PERC panels. This results in a potential 2% power generation gain, boosting overall energy output.
Extended Power Warranty Period: The N-type silicon substrate, doped with phosphorus, avoids the boron-oxygen pair degradation common in PERC cells. This nearly eliminates light-induced degradation, ensuring a longer warranty period.
Low Investment for Upgrades: TOPCon technology is compatible with PERC production lines, requiring only additional equipment for boron diffusion and the preparation of tunnel oxide and polysilicon layers. Most of the existing processes remain unchanged, simplifying the upgrade.
Applications of TOPCon Solar Modules
Residential and Commercial Systems: TOPCon panels are ideal for rooftop or ground-mounted installations, providing efficient renewable energy for homes, businesses, and industrial facilities.
Utility-Scale Solar Plants: In large-scale solar farms, TOPCon panels maximize power generation within limited space, lowering electricity costs and improving project efficiency.
Agricultural Solutions: Perfect for off-grid or remote areas, TOPCon panels can power essential agricultural equipment like water pumps and irrigation systems, helping farmers boost productivity.
Electric Vehicle Charging: As EV adoption grows, TOPCon panels offer a clean energy source for charging stations, supporting sustainable and green transportation initiatives.
Building-Integrated Photovoltaics (BIPV): TOPCon technology enables seamless integration into building designs, combining energy generation with aesthetic architectural elements.
Coastal and Offshore Areas: Thanks to their high durability, TOPCon panels are well-suited for regions with high salt mist and humidity, ensuring reliable performance in challenging environments.
Future Development Predictions for TOPCon Solar Modules
TOPCon solar cells are projected to witness substantial market growth from 2023 to 2030, driven by their superior conversion efficiency and reliable performance. As production scales up and technology matures, manufacturing costs are expected to decline, enabling greater adoption in large-scale photovoltaic power stations and commercial applications.
Policy incentives and the global emphasis on sustainable development are further accelerating the integration of TOPCon technology. The rising demand for clean energy, particularly in sun-rich regions, is expected to propel technological advancements and expand the photovoltaic market, solidifying TOPCon’s role in the renewable energy sector.
Reference:
https://guangfu.bjx.com.cn/news/20200710/1088087.shtml
https://guangfu.bjx.com.cn/news/20200710/1088087.shtml
https://xueqiu.com/2305761063/241967340
https://guangfu.bjx.com.cn/news/20200710/1088087.shtml
https://www.sohu.com/a/640762583_121123896
https://www.verifiedmarketreports.com/product/topcon-solar-cell-and-module-market/
TOPCon Products of Maysun Solar
Efficiency: 21.9%-22.6%
Dimensions (L × W × H): 2279 x 1134 x 30 mm
Weight: 29 kg
Packaging: 37 pcs/pallet, 740 pcs/40'HQ
Warranty: 15-year product guarantee and 25-year power guarantee
Efficiency: 21.7%-22.4%
Dimensions (L × W × H): 2279 x 1134 x 30 mm
Weight: 32 kg
Packaging: 36 pcs/pallet, 720 pcs/ 40'HQ
Warranty: 30-year product and power warranty
Efficiency: 21.5%-22.3%
Dimensions (L × W × H): 1722 x 1134 x 30mm
Weight: 24 kg
Packaging: 36 pcs/pallet, 936 pcs/40'HQ
Warranty: 30-year product and power warranty
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