Jolywood has been awarded ‘Best Performance’ status by PVEL in the 7th release of its PV Module Reliability Scorecard for the company’s high-efficiency, high-power and high-reliability N-type TOPCon modules.
As a world leading independent laboratory, PVEL tests solar modules from leading manufacturers as part of its Product Qualification Program (PQP) and publishes the annual Reliability Scorecard based on these test results.
The PQP covers multiple tests such as thermal cycle, damp heat, dynamic mechanical load, PID (Potential Induced Degradation) and PAN file. Jolywood’s N-type TOPCon module was classified as excellent, especially in “PID192/LID+LETID” testing.
Due to its advantages in raw materials and structure, an N-type TOPCon cell has many benefits such as no PID, zero LID (light-induced-degradation), better weak light response, lower risk of cracking, high performance and high reliability.
In terms of cells, Jolywood has achieved outstanding results in N-type TOPCon technology over recent years. The newly released J-TOPCon 2.0 cell is based on a new generation of tunnel oxide layer and doped polysilicon deposition passivation contact technology. It has the advantages of no LID degradation, low temperature coefficient and high reliability, which provides a strong platform for further reducing the cost of electricity.
A Fraunhofer study published at the EU PVSEC in September 2018 showed LeTID to be prevalent in all commercial components available on the market. It occurs when module temperatures exceed 50°C and its causes include factors such as hydrogen-induced degradation, passivation degradation and metal impurities. LeTID can exceed 10%, which is much higher than LID.
In November 2018, UNSW reported its latest research on LeTID. The research showed that:
1) LeTID degradation mainly occurred in the body area, followed by surface inactivation;
2) With the increase in temperature, LeTID increases;
3) For phosphorus-doped N-type silicon wafers, recovery can be observed after LeTID degradation under light conditions and the recovery time decreases with the increase of light;
4) For phosphorus-doped N-type silicon wafers, no secondary LeTID was observed after recovery under 1~1.5 solar irradiation.
Fraunhofer and NREL researchers have systematically studied and tested module temperatures in different environments, indicating that temperatures will exceed 75 ° C in desert and hot and humid areas. In high temperature areas like the Middle East, particular attention should be paid to a module’s anti-LeTID performance. N-type bifacial modules are characterized by:
1) N-type silicon. There is no B-O defect composite as in P-type silicon, meaning a longer lifetime, less affected by LeTID.
2) N-type bifacial modules can allow part of near-infrared light to pass through, with a lower working temperature and lower LeTID;
3) In light conditions, the LeTID will recover quickly, the greater the light intensity, the faster the recovery;
4) No secondary LeTID after recovery. Therefore, N-type bifacial modules have excellent anti-LeTID performance with their natural properties.
Significant outdoor evidence indicates that Jolywood modules have very low levels of LID, far better than mainstream bifacial products in the market. LID will play an important role in total return on investment and capital and cost per kilowatt hour for a photovoltaic project. In the case of highest and lowest LID, the difference in the total investment rate of return can reach 0.8%, while the difference in kWh cost will reach 1.8 cents/kWh. If the back gain of a bifacial module and double-glass is considered, the difference will reach about 3%. Therefore, when selecting modules, the impact of LID should be fully considered.
Jolywood’s new Niwa series of high-efficiency modules incorporates a total of 3 products. ‘Niwa Pro’ and ‘Niwa Super’ are equipped with the world’s first J-TOPCon2.0 half cell technology, which can be widely used in large-scale ground power, floating power, and distributed power stations and BIPV projects. The more than 80% bifaciality makes the modules suitable for various installation environments, including vertical and oblique, and high-efficiency power generation can also be maintained under extreme conditions such as snow, desert/extreme temperatures, strong wind and sand. The ‘Niwa Black’ module is mainly used in BIPV applications, adopting an aesthetically attractive all-black design and providing high-efficiency power generation.
In 2021, the demand for PV will increase. Exwatt forecast that new module capacity will reach 100GW by the end of the year. As the price of raw materials rises, module manufacturers are faced with a tough choice between cost and quality. With the advent of large size modules and half cell design, there is a greater risk of cracks and the market is presenting higher requirements for reliability in this area.
Lower Micro-crack Risk
The crack is a defect produced inside solar cells which cannot be seen by the naked eye, so the help of professional testing equipment is required. However, cracks will seriously affect the lifetime of a power station and actual power generation, so present a serious issue in the construction phase of a plant.
N-type monocrystalline bifacial solar cells have a symmetrical structure and less internal stress. Silver paste is printed on both sides of the N-type cells to improve stability, giving them higher reliability, especially in sandstorm conditions such as those found in the Middle East.
In an increasingly prosperous photovoltaic market, products are competing for leadership. With its excellent product quality management and control ability, allied to testing and R&D strength, Jolywood stands out with its high efficiency, reliable N-type TOPCon solar modules and has established itself as a leader in this area of technology.