Solar PV technology has captured the world's imagination of late, including policy makers and businesses, thanks mainly to of course its falling costs as it makes economic sense. Looking at its growing demand across the world, solar PV manufacturers are expanding their production capacities to levels unheard before.
While it is extremely important to lower costs by expanding solar PV manufacturing capacities, it is equally significant not to lose track of the fact that the reliability factor of a module remains intact in the process. To discuss the reliability factor of solar modules and how to ensure it during the manufacturing process itself, TaiyangNews brought together key stakeholders active in various parts of solar module manufacturing for our 1st Reliable PV Module Design Conference on October 9, 2020.
During the executive panel discussion held, industry experts discussed the relevance of certifications for long term module warranties and the importance of extensive testing for truly reliable modules in the market. PV Evolution Labs (PVEL) CEO Jenya Meydbray opined that performance test certifications are helpful to keep really faulty products out of the market, but they do not always end up keeping all the faults out of the product that may start appearing after a few years on the field. 'This is the lowest level to keep safety standards, etc., but to make sure that modules are long lasting in the field it needs third party testing, said Medbray. The panel agreed that the common IEC tests are just the required entry level, but that sequential tests, developed by NREL or PVEL is what's needed to test module quality thoroughly.
DuPont's Global Marketing Manager Mark Ma pushed for a more stringent testing protocol for solar modules with longer life duration and raise the bar to win certifications.
Encapsulant leader HiUV's Vice President Colin Quan believes there is no test that can accurately evaluate the durability of a solar module for 25 years. What's the industry can do then is to go in for extensive testing, learn from the field results and incorporates the learnings within the manufacturing process itself. He also took the platform to share his company will be expanding its annual production capacity to 40 GW in 2021, increasing it from 20 GW in 2020.
Solyco CEO Dr. Lars Podlowski believes some responsibility lies on the shoulders of end consumers to ensure they ask for the right product since manufacturers are also sometimes just fulfilling market demand for products with longer warranties. In the end, you also get what you pay for. If customers only go for the lowest price products, they have to live with the consequences.
These days, with a lot of innovations being implemented into module designs – larger wafers, high efficiency cell technologies, advanced module connections, it is difficult for testing institutes to catch up. Theoretically it needs 5 years before all the issues are understood, but at the current pace this is not possible. "The only way is third-party testing," the panel said unanimously.
However, testing doesn't start with the final module, but rather during the product design phase. Speaking at the conference, Polymer Competence Center Leoben Division Head Smart Materials, Gernot Oreski stressed on extensive testing of actual samples at every step of the way right from resins, polymer films, laminates, mini modules and finally the full size modules. As the solar PV market proliferates there are bound to be several suppliers of different module components. To ensure these are compatible with each other to be able to lead to a strong module design, testing cannot be less important, according to Oreski.
Solar module maker Astronergy Chint took the role of a tier 1 producer, showing its high-degree of automation and extensive quality control, including MES and artificial intelligence tools. Project Manager Aj Hu listed the checklist her company deploys to cross check and eliminate any problem areas in their end product. Relying on non-destructive cutting (NDC), Astronergy said it improves the bending strength of cells and mechanical properties of modules. The module company decided to use double glass for its bifacial modules as Hu said it provides better protection against fire, water, wind and snow. At the conference, Hu also shared Astronergy plans to expand its annual module manufacturing capacity to 15.5 GW by 2025, increasing it from 7.5 GW in 2020.
On the other hand, Jolywood representing the backsheet side of the module BOM, was supporting transparent backsheet solutions for bifacial products. Michael Chen from the marketing department of the company also emphasized the use of double coated backsheets as the most attractive solution from a quality/cost ratio.
Adding the encapsulation material perspective on module reliability, Colin Quan, vice president of leading encapsulation material supplier HIUV, has discussed two important degradations – PID and snail tracks.
Indian solar PV glass manufacturer Borosil Renewables' Head of Marketing Swapnil Walunj batted for glass-glass modules as being better at handling thermal stresses compared to glass-backsheet modules. Referencing to some sequence test results, Walunj stressed that glass-glass modules are more robust to cell cracking. He also offered a possible solution to the concern regarding weight of glass-glass modules, Walunj suggested one could look at using a frameless glass-glass module with 2mm glass, which he said will have almost the same weight as compared to glass backsheet modules. Glass-glass modules also offer a promising prospect in the floating solar space, according to Walunj.
Stressing the need to save a solar module from degradation for as long as possible during its lifetime, DuPont's Global Technology Leader Kaushik Roy Choudhury said backsheet failures can occur both on outer and inner layers. However, he offered field test results to show DuPont's Tedlar based transparent backsheet can overcome many of these defects compared to competing technologies in the field. These Clear Tedlar based backsheets help lower the overall weight of solar modules compared to incumbent double glass bifacial panels, argues Choudhury, calling these a better fit for higher power, bigger sized modules with 500W and above power output.
TaiyangNews Market Survey 2020 launched
The 1st Reliable PV Module Design Conference was also the occasion for the official launch of TaiyangNews Backsheet & Module Encapsulation Market Survey 2020. The Head of Technology at TaiyangNews Shravan Chunduri discussed the major findings of the survey basis responses from 13 participants for 89 products in total. The report places Cybrid at top of the list among backsheet suppliers, followed by Jolywood and Hangzhou First, which is also a coatings supplier. As for encapsulants, the survey sees 3 dominant market leaders with Hangzhou First holding over 50% of the market, followed by Sveck and HiUV.
The most popular backsheet in the market currently, as per TaiyangNews survey, is a PVDF film on the outer side and fluorine coating on the inner side with PET as the core layer, while transparent backsheet is the hot topic of discussion among backsheet makers.
Several companies are now evaluating transparent backsheets space with JinkoSolar and Jolywood now offering 30-year power warranties, a level that is 5 years above what's on offer for glas-backsheet products and was only offered for glass backsheets. Some backsheet suppliers believe grids to improve internal reflection in bifacial modules would become a standard with transparent backsheet in the near future.
Another interesting trend reported by the survey is the coextrusion process to make multi-layer backsheets in a single step directly from resin, however Chunduri pointed out that the technology still hasn't been able to win major Chinese backsheet producers.
The TaiyangNews Backsheet & Module Encapsulation Market Survey 2020, which provides also detailed product specs from leading suppliers' models is available for free download.