A topic of optimization that is gaining attention in PV manufacturing is one of different wafer sizes. But unlike in the past, the discussion around it is more subtle now. This time around, manufacturers seem to agree that there needs to be standardization of module sizes, irrespective of wafer sizes. In this context, Trina Solar is pushing for 3 sizes, characterized as "golden sizes" for each of the mainstream applications – residential, C&I and utility. This was also the center theme of Trina's product manager Rocky Li's presentation at the TaiyangNews conference (see recording here).
However, he started by detailing the progression of Trina Solar's i-TOPCon technology, outlining its evolution across 4 pivotal stages. Between 2015 and 2019, during the i-TOPCon phase, the company achieved a lab-scale efficiency of 23.5% with a 158.75 mm wafer size. The company also established a 500 MW lab line during this period. From 2020 to 2022, the i-TOPCon Plus stage marked the integration of the TOPCon technology with the more substantial G12 wafer format, leading to an elevation in the average production efficiency to 24.5%. The subsequent stage, which is also the current one, characterized as i-TOPCon Advanced, has witnessed a series of technological breakthroughs. Looking ahead, the i-TOPCon Ultra Tandem phase aims to achieve full frontal passivation contacts with an efficiency target of 27%. With the integration of perovskite tandem cell technology, there's potential to push the efficiency to an impressive 30%.
At the current phase of i-TOPCon Advanced, Li emphasized 4 important characteristics. The first one is the introduction of the innovative rectangular cell on the 210 platform, the G12R (182 x 210 mm format). This has enabled the company to develop modules with golden sizes. The other 3 are use of large area boron doping by laser selective emitter technology, the development of back side microstructure reflectors to boost efficiency, and the incorporation of high doping and low composite tech structures using the PECVD route. All these improvements have collectively enabled Trina to realize a cell efficiency of 25.8% and the company expects to push it further to 26.6% during 2027.
Based on this i-TOPCon technology, Trina Solar has launched 3 modules, each for a different application: residential, C&I, and utility. These modules are also promoted as the "golden size" by Trina for each of the respective applications, and Li also explained the rationale behind why the sizes are called as such.
The residential module, called Vertex S+, built with 40 of G12R cells sliced into 3 pieces. It is a doubleglass product with 1.6 mm glass used on each side. It has a power rating of 450 W and an efficiency of 22.5%. Measuring 1,672 x 1,134 x 30 mm, the module area of 1.998 m2 is very close to the upper limit of 2 m2, exploring the size limit set by German building regulation to the maximum possible extent. At its weight of 21 kg, the module is less than 51 lbs, making it safe and easy to install. Li claims that compared to other typical products in the market based on M10 and G12 cell sizes, the Vertex S+ modules facilitate 5.88% more installation capacity for the same roof size and higher container utilization rate.
Vertex N is yet another module of the company that is built on the G12R wafer format but is promoted for C&I and utility. These modules measuring 2,384 x 1,134 x 30 mm are slightly longer than a typical M10 based module of comparable form factor. With slightly lower voltage of 3.6 V than the reference, the Vertex N enables connecting 2 additional modules per string in a tracker. Li claims that a 1P tracker installed with the latest Vertex N has 13% more power over the reference. This reflects as a saving of $0.0053/W on tracker costs. In addition, the Vertex N has a high container utilization rate of 98.5%, which increases the total power of modules loaded per container by 5.2%. The third one is a larger format module designed for utility applications. The module is based on the G12 wafer format, has a power rating of 700 W and 22.5% efficiency. With a dimension of 2384 x 1303 x 30 mm, these modules are adapted to vertical packaging, which also helps in maximizing the container space utilization rate to 97.6%. Trina Solar characterized these modules also as the golden size for utility applications.
Trina Solar says that its golden size philosophy is widely accepted by the industry. Several companies have upgraded their products with these 3 sizes at SNEC and Intersolar. Li also presented hypothetical case studies for both the mid-sized and larger modules, showing that these products reduce the LCOE. The i-TOPCon modules from Trina have exceeded the requirements of several internationally recognized testing protocols and were awarded with PVEL's top performer for the ninth time in a row. Li also presented an update on the overall product capacity of Trina along the value chain for 2023: 50 GW for wafers, 75 GW for cells of which i-TOPCon represents 40 GW, and 95 GW for modules.
The text is an excerpt from TaiyangNews New Solar Products Overview H1/2023, which can be downloaded for free here.