Trina Solar has published an analysis of the high mechanical reliability of its Vertex 670W module, following the product’s exposure to six rigorous tests, including 35mm hail, non-uniform snow-load, extreme DML, extreme wind tunnel and extreme low-temperature mechanical load.
In the 35mm hailstone test, the power attenuation of a single-glass 670W module was just 0.17%, with no attenuation detected in a dual-glass module.
Under the stringent requirements of the IEC 61215 standard, hail testing of the Vertex module simulated the shock of hail on its surface. Using a pneumatic emission device, natural hail was replicated, with artificial ice balls with a diameter of 35mm hitting the module at a constant speed of 27.2 metres per second.
Post-test inspection of the module surface showed it to be intact with no evidence of micro-cracks.
The Vertex module also passed insulation and wet leakage tests, with power attenuation of the single-glass module again only 0.17% with no attenuation detected for the dual-glass version.
A PV module’s capacity to withstand hail is mainly related to the material of its frontsheet, in this case glass. The thickness of the glass and its tolerance to shock have a direct bearing on this capacity.
Chen Lin, technology head at Xinyi Glass Holdings, commented: “We have enlarged the size of our steel furnace, adjusted fan configuration and strictly controlled our manufacturing and management processes, so that the steel strength of the glass, which is matched with 210 modules, is guaranteed, with full technological reliability.”
In a 210 module, the ability of the glass to resist shock fully guarantees its safety and reliability.
Additionally, based on the structural features of its various module types, Trina Solar has special requirements for the performance of glass. The inspection and test specifications for both suppliers and Trina itself ensure that the reliability of the glass is fully integrated into the design and structure of its products, creating a corporate benchmark promoted as a potential standard for the whole industry.
In 2007 Trina Solar adopted a management policy of continual reliability testing to establish a material ORT concept for the industry, incorporating this into the company’s own corporate reliability standards. Also included were full series testing programs such as IEC 61215, 61730 and 63216. In most cases, Trina internal requirements are now set at a level two to three times that of the required IEC standards.