Trinasolar has completed a field test which has found that TOPCon PV modules deliver an average power generation gain of 3.15% per watt over back contact (BC) modules, with a relative gain of up to 3.4% on a monthly basis. This analysis would demonstrate the superior power generation of TOPCon modules the company claims.
The test was conducted between 16th July and 10th September 2024 in Changzhou, China. Trinasolar compared the performance of its Vertex N 600W bifacial dual-glass modules, based on advanced n type i-TOPCon technology, with 620W bifacial dual-glass tunnel back contact (TBC) modules from an alternative manufacturer.
To ensure accuracy, the test site was designed to closely simulate regular installation conditions. It featured a cement ground with around 30% reflectivity, with modules mounted on fixed racking systems with a 23° tilt angle and installed 0.5 metres above the ground. There was no shading on the front or rear rows, and power generation data was collected using an IV tracker.
High bifaciality and low-irradiance performance
The TOPCon modules demonstrated superior performance in low-irradiance conditions such as in the morning and early evening. From 7am to 8am, the TOPCon modules’ power generation per watt was 6.9% higher than the TBC modules, and from 5pm to 7pm, its relative gain was 8.3-8.4%. This is in line with earlier field tests showing that TOPCon outperforms BC by about 5% in low-irradiance conditions.
TOPCon’s higher bifaciality also contributes to its greater power generation: even at midday when sunlight is strongest, TOPCon modules deliver a 2.6% power generation advantage over BC alternatives.
Trina Solar
The combination of high bifaciality and low-irradiance performance enables TOPCon modules to deliver a 2-3% power generation gain per watt over BC modules in actual operating conditions. These findings are consistent with results from the National Photovoltaic and Energy Storage Experimental Platform and the National Centre of Inspection on Solar Photovoltaic Products Quality, both based in China.
Further e fficiency gains expected
The test results would provide strong evidence that TOPCon will be the dominant PV technology over the next five years Trina Solar claims, with further improvements to efficiency and reductions in costs still to come. Trinasolar envisions that efficiency of the cells will increase by an additional 1% in this time, and that the power output of TOPCon modules will grow by over 30W in the same period. In five years’ time, the company expects n-type TOPCon-based perovskite-silicon tandem solar cells to become the benchmark for high-quality development in the PV industry.
Recently AIKO claimed the advantages of the back-contact technology with field results from their N-Type ABC PV modules and Longi also emphasizes the advantages of its back-contact cell and module technology. (hcn)
