Technological advancements in solar cell technology have played a pivotal role in improving the efficiency and cost-effectiveness of solar energy. With the PERC cell having reached its limits, one such innovation that has gained significant attention in recent years is TOPCon (Tunnel Oxide Passivated Contact) cell technology.
You can find more information on our web, so please take a look.
In this blog post, we will explore what TOPCon cell technology is, its advantages over PERC cells, and its current and projected market share.
Benefits of TOPCon Technology
Some notable benefits of this new cell technology include:
Adaptability to the existing manufacturing process
One of the key benefits of TOPCon cells lies in their seamless integration with the current manufacturing infrastructure. As TOPCon cells can be produced using similar equipment as PERC cells, the transition to this new technology from existing PERC production lines is smooth and cost-effective. A slight increase in cost allows for easy upgrading to TOPCon solar cells, making it a viable and efficient option for manufacturers.
Higher efficiency
TOPCon cells reach an efficiency of around 28%, which is significantly higher than the efficiency of PERC cells, which is typically around 22%.
RenewSys N-type TOPCon modulesEnhanced low-light performance
TOPCon cells exhibit higher efficiency in low-light conditions, enabling them to generate electricity even when sunlight is limited.
Better performance in a hot climate
TOPCon panels have a lower temperature coefficient, usually < (-)0.30 %/°C. This results in less power reduction with every degree rise in temperature, allowing TOPCon panels to outperform mono PERC panels in hot climates by generating more power.
Increased energy generation
When compared to PERC modules, TOPCon modules demonstrate significantly lower power degradation both within the first year and over their extended 25 to 30-year lifespan. As a result, TOPCon panels consistently produce more energy throughout their operational lifetime.
Improved bifaciality
TOPCon cells have a higher bifaciality than PERC cells, generally 80-85%, which means they can generate more electricity from the rear side of the cell. This is important for solar panels that are installed in bifacial configurations.
What is TOPCon Solar Cell Technology?
TOPCon cells are a type of n-type solar cell. N-type cells are made with a semiconductor material that has been doped with phosphorus, which gives the material a negative charge. This type of cell has several advantages over p-type cells, including higher efficiency and better performance in low-light conditions.
TOPCon cell technology is a further development of PERC technology. In PERC cells, the rear surface of the solar cell is passivated with a thin layer of aluminium oxide (Al2O3). This layer helps to reduce recombination losses, which can improve the efficiency of the cell.
In TOPCon cells, a thin layer of silicon dioxide (SiO2) is deposited on top of the Al2O3 layer. This layer creates a tunnelling junction, which allows electrons to flow more easily from the p-type emitter to the n-type substrate. This tunnelling junction helps improve the efficiency of the cell by reducing the series resistance.
TOPCon cells are generally n-type. N-type cells are made with a semiconductor material that has been doped with phosphorus, which gives the material a negative charge. This type of cell has several advantages over p-type cells, including higher efficiency and better performance in low-light conditions.
Current and Estimated Market S
hare
潞安 Product Page
Currently, TOPCon cells hold a relatively small market share, but it is growing rapidly. In , TOPCon cells accounted for about 10% of the global solar cell market. However, TOPCon is expected to become the dominant cell concept after and is estimated to reach a market share of around 60% by , according to the International Technology Roadmap for Photovoltaic (ITRPV), April edition.
Data credits:
RenewSys R&D
International Technology Roadmap for Photovoltaic (ITRPV), April edition
Image credits:
RenewSys
Solar cell technology used to manufacture photovoltaic (PV) modules is constantly evolving as new, more advanced and more efficient technologies are developed. Tunnel oxide passivated contact (TOPCon) solar cell technology is a new development with the potential to replace passivated emitter and rear contact (PERC) and high-efficiency passivated emitter, rear totally-diffused (PERT) solar panels.
TOPCon solar cells represent an upgraded and more efficient technology compared to PERC/PERT solar cells, featuring a highly similar structure.
In this article, we will explain important details on this technology, going from the basics, structure and manufacturing, comparison against other popular technologies in the solar industry, advantages and disadvantages, and more.
Tiger Neo bifacial TOPCon solar panel - Source: Jinko SolarTOPCon solar cell technology: Understanding the basicsTOPCon solar cell technology is one of the latest trends in the solar industry, developed as an upgraded and more advanced version of the PERC/PERT technology. One of the main advantages of TOPCon solar cells is that the structure is only slightly different from PERC/PERT solar cells, meaning that manufacturers can use practically the same production line with a few improvements to produce TOPCon solar cells.
TOPCon solar cell technology was first introduced as a concept in by the Fraunhofer ISE German PV research institute. The project designed to develop this technology took place from to , but it was not until that companies like Trina Solar scaled it to production. As TOPCon solar cell technology proved as a successful upgrade from PERC solar cells, many other companies including LONGi Solar, Suntech, Canadian Solar, and many others got interested in it.
The main setback of this new technology compared to PERC/PERT is that the TOPCon solar cells require a larger amount of silver (Ag) for production. This silver increase translates into a higher manufacturing price; however, new developments might prove successful in reducing the required amount of silver, while still delivering similar or even higher efficiencies and reducing production costs.
Structure and manufacturing of TOPCon solar cellsTOPCon solar cell technology features a similar structure and manufacturing process to PERC solar cells, featuring only a few additional steps. In this section, we explain how both of these work:
Structure of the TOPCon solar cellTOPCon solar cells can be manufactured as n-type or p-type solar cells, but the n-type variation has proven to be more efficient and resistant to impurities. Because TOPCon solar cells are an upgrade from PERC/PERT solar cells, it is important to understand the structure of this new technology.
PERT solar cells are manufactured with an n-type crystalline silicon (c-Si) bulk layer because of its higher surface quality and it is coupled with a p+ emitter layer to create the p-n junction. The emitter layer is covered with an aluminum oxide (Al2O3) passivating layer and topped with a silicon nitride (SiNx) coating for its anti-reflecting properties. PERC solar cells replace the absorber layer with a p-type bulk layer and an n+ emitter for the p-n junction.
The lower part of the bulk region is doped with phosphorous to create the back surface field, and it is then coated with SiNx similar to the top of the cell. Both the top and bottom of the solar cell are equipped with silver (Ag) or aluminum (Al) contacts to close the circuit when the cell is being connected to the load or other cells at the time of manufacturing the PERC/PERT solar panel.
TOPCon solar cell structure - Source: Scholarly Community EncyclopediaThe PERC/PERT solar cell structure has proven to be quite efficient since it was introduced to the market and implemented to manufacture PV modules, but researchers found ways to improve it and therefore created the TOPCon solar cell.
The TOPCon solar cell structure takes the base structure of the PERT solar cell but includes an ultra-thin silicon dioxide (SiO2) layer working as the tunnel oxide layer and replaces the back surface field layer with phosphorous-doped polycrystalline silicon (n+ Poly-Si) layer. These modifications have improved the efficiency by reducing the recombination process thanks to the passivation in the added layers.
Manufacture of a TOPCon solar cellOne of the best things about TOPCon solar cell technology is that the manufacturing process is so similar to that of PERT solar cells that manufacturers will only have to make a little investment to upgrade their existing production line. Most of the manufacturing equipment can remain the same. This makes TOPCon solar cells an excellent investment for PERC/PERT PV module manufacturers already in the market.
After the TOPCon solar cells are manufactured, I-V solar cell curve characterizations are performed to evaluate their performance.
There are only a few additional steps required to manufacture a TOPCon solar cell instead of the PERT solar cell, making this new technology financially attractive for the solar industry.
How do TOPCon solar cells compare against the most popular PV technology in the market?Power degradation of TOPCon cell over its 30-Year lifespan - Source: Jinko SolarTOPCon solar cell technology is quite promising, having the potential to rapidly grow within the solar industry. When considering a new rising technology like this one, it is important to analyze it against other popular PV technologies in the market. In this case, we will compare TOPCon solar cell technology against PERC and heterojunction (HJT) solar cell technologies.
Highest EfficiencyTemperature CoefficientBifaciality FactorMarket ShareTOPCon26.10%<0.3%/ºC85%8% ()PERC24.50%<0.4%/ºC70%75% ()HJT26.56%0.21%/ºC92%2.5% ()PERC solar cell technology currently sits in the first place, featuring the highest market share in the solar industry at 75%, while HJT solar cell technology started to become adopted in , its market share was only 2.5% by . TOPCon, which is barely present in the market, already represents 8% of the PV market, but it might start to grow in as major manufacturers switch from PERC/PERT to TOPCon.
Considering the technical specs, PERC technology is left behind by both HJT and TOPCon solar cell technologies. While PERC features a 24.5% efficiency and 70% bifaciality factor, TOPCon takes the efficiency to 26.1% and the bifaciality factor to 85%, while HJT goes even further with an efficiency of 26.56% and bifaciality factor of 92%. The temperature coefficient for PERC solar cells is worse when compared to TOPCon with its 0.3%/ºC, while HJT solar cells go even lower than that to 0.21%/ºC.
HJT solar cells might look quite promising, but there are major setbacks to this technology because of the higher production cost for solar cells and the incompatible production line with current technologies. This is where TOPCon solar cells have a head start since the required production line for TOPCon solar cells is practically the same as PERC/PERT and the cost is also quite similar.
Considering the similarity between the technical specifications of HJT and TOPCon solar cells, but factoring in the setbacks of HJT technology, it is understandable why major manufacturers like Trina Solar, Jinko Solar, LONGi, and others, are opting for TOPCon solar cells instead of HJT.
TOPCon solar cells feature a few differences from PERC/PERT solar cells but greatly improve performance. In this section, we present the advantages and disadvantages of TOPCon solar cells.
AdvantagesLittle capital investments for PERC/PERT manufacturersTOPCon solar cell technology is an upgrade of PERC/PERT solar cells, featuring two additional steps. This little difference between both technologies, allows manufacturers of PERC and PERT solar cells to upgrade to TOPCon by adding only a few pieces of equipment for a little investment.
Higher efficiency reported by several manufacturersOne of the main features of TOPCon solar panels is the higher efficiency achieved. According to the Fraunhofer ISE institute, efficiencies can go beyond 25%. This has already been proved by PV manufacturers like LONGi, Jinko Solar, and others, with a high efficiency of 26.1%.
Better performance as a result of a lower temperature coefficientTraditional PV modules feature a temperature coefficient of 0.4%/&#;-0.5%/&#;, while PERC PV modules perform better by taking that coefficient slightly under the 0.4%/&#; frame. TOPCon PV modules manufactured by Jinko Solar, on the other hand, have already proven to take the temperature coefficient to less than 0.3%/&#;, highly improving their performance in many extreme weather scenarios.
15% higher bifacial factorThe bifacial factor for PERC PV modules has been determined on average to be at around 70%. TOPCon solar panels, on the other hand, have proven to take the bifacial factor up to 85%. This increased bifacial factor can increase power gains by as much as 2%.
DisadvantagesSeveral challenges in the manufacturing processTOPCon solar cell technology is still facing several challenges in the manufacturing process. Some of these include different opinions on the best technique for boron deposition, different requirements for clean room conditions that have to be met, and the inability of the current selective emitter to apply to the TOPCon front emitter. For the solar industry to advance with TOPCon, these issues should be addressed.
There is little data about mass production, limiting the roadmap for the futureDifferent companies upgrading their PERC/PERT lines of production to TOPCon solar cells have taken different routes, but since there is limited mass production, the roadmap for this technology is still under development. As major companies like Trina Solar, LONGi, and others start to tackle major problems and find optimal ways to produce TOPCon solar cells, the roadmap will become clearer.
Higher silver requirement equals higher priceOne of the major issues of TOPCon solar cells is a higher requirement of silver to print the contacts on the cell. The ideal option to reduce costs would be to increase efficiency while maintaining current costs. Lowering the costs for this technology is imperative to hit the market at reasonable prices.
Market trends featuring TOPCon solar cellsThe market trends have shifted in the last decade from back surface fields (BSF) solar panels to PERC solar cell technology, and now it seems to be shifting to TOPCon solar panels. Initially, BSF solar panels ruled the market, but manufacturers began the adoption of PERC solar cell technology and the market share grew until hitting 40% in , and almost 75% by . Since TOPCon solar cell technology is a cost-efficient upgrade from PERC/PERT solar cells, this new technology may soon rule the market.
In , LONGi announced a new record for high-efficiency n-type solar panels at 25.21% featuring TOPCon solar cell technology. Little after that, Jinko Solar announced an even higher efficiency record at 25.4%. In , Trina Solar broke the record with an efficiency of 25.5%, while Canadian Solar also reached a high efficiency of 25.0% that same year. By the end of , Jinko Solar broke the record two times in a row, first reaching 25.7% and then 26.1%.
Many PV manufacturers will start to fill the market with TOPCon solar panels as they design and release their products. LONGi launched its bifacial TOPCon solar panels at the SNEC , and Suntech released its Ultra VPro Series in , but it seems that will be the year when most PV manufacturers release their products. Jinko Solar unveiled three different TOPCon solar panel variants with a power rate going from 445W to 635W, Canadian Solar is also hitting the market with solar panels that go up to 690W, and Trina Solar unveiled its new TOPCon solar panels that go up to 445W.
These are only some of the largest manufacturers, but as the technology advances, other major companies in the solar industry will also release TOPCon solar panels. There is a considerable possibility that as TOPCon solar cell technology becomes more popular, PERC solar panels will start to give way to TOPCon to increase its market share and presence in the industry.
Present and future of TOPCon solar cellsTOPCon solar cell technology is a revolutionizing product that upgrades the design of the PERC/PERT solar panels.
This technology has already proven its worth by reaching efficiencies that approach the Shockley-Queisser limit for single p-n junction solar cells and deliver a better performance in general.
The solar industry is starting to get acquainted with TOPCon solar cell technology. LONGi already launched its bifacial modules in , but most manufacturers will be releasing their high-efficiency TOPCon solar panels from the second (Q2) to the last quarter (Q4) of .
It is possible that at first, TOPCon solar cell technology will have slightly more expensive costs than PERC/PERT solar panels, but analysts expect that the cost for TOPCon solar panels will fall lower than the current cost of PERC solar cell technology.
The path for TOPCon solar cell technology is also not entirely free from competition. There are other technologies featuring an interesting great potential to go against this newly upgraded technology, including HJT as it is further developed, and interdigitated back-contacted (IBC) solar cell technology.
For more information, please visit topcon solar cell.