With the increase in the size of photovoltaic modules, the ability of photovoltaic modules to resist extreme weather throughout their life cycle has attracted widespread attention from the industry.
Recently, LONGi Hi-MO 5 double-sided components completed uneven snow load test at the Certification Center, and the results showed that under the condition of simulating beamless installation (the back of the component does not touch the beam when deformation), the critical snow load (value at the time of failure) of LONGi's 5 Hi-MO 5 pieces reached or exceeded 6400Pa, the maximum value reached 7400Pa, the non-uniform snow load bearing capacity after considering the safety factor was 4341Pa, and the area tested during the same period was 3.1m2 (2384×1303mm) The average critical snow load of the component is 4600Pa, the non-uniform snow load carrying capacity after considering the safety factor is about 3000Pa, and the performance advantage of Hi-MO 5 is more than 1000Pa.
Following the wind tunnel test, hail test and extreme dynamic load test, the rationality and high reliability of the size and structural design of LONGi components have been confirmed.
01 The significance and method of uneven snow load test
In the actual application environment, the component bears snow closer to the bottom relatively thicker, resulting in the component load is non-uniform, with the component length increase, width increase, non-uniform snow load brought about by the local pressure and bending moment are significantly increased, so it is necessary to evaluate the ability of large-size components to carry non-uniform loads.
IEC 62938:2020 uneven snow load test standard is to apply a non-uniform load of step distribution to the 2/3 part of the component at a certain inclination angle (usually 37 °), the load is gradually increased until the component is broken, the critical load value of 5 components is obtained, and the non-uniform snow load carrying capacity of the component is obtained after considering the safety factor of 1.5.
02 Hi-MO 5 uneven snow load test results
Large-size double-sided components are currently mainly vertical installation, in order to avoid the impact of the bracket beam on the back of the power generation, usually use the briquette to raise the component to increase the distance between the glass on the back of the component and the beam, this test uses a similar installation method, the back of the component will not touch the beam in the test, compared to the conventional test is more stringent.
In addition to obtaining the ultimate load value when the component is broken, the test also records the shape variable of the lower edge of the component relative to the center point under different loads. In addition to the Hi-MO 5 component significantly ahead of the 3.1m2 component (2384×1303mm) tested in the same period in terms of ultimate load value, the shape variable of the component under a certain pressure is also significantly lower than that of the 3.1m2 component.
The critical load value of the 3.1m2 component, which is compared with the same period of test, is low, and the component shape variable has exceeded 50mm under the pressure of 3600Pa, and the excessive deformation variable that has been subjected to a large shape variable for a long time in practical applications is also easy to cause problems such as cracking of the internal battery blade, frame deformation, and glass damage.
In summary, the size of the component size is strongly related to the mechanical properties of the component, whether it is the limit dynamic load test, hail test, wind tunnel test or uneven snow load test, indicating that the component size should have a reasonable boundary. The Hi-MO 5 maintains high reliability in extreme climatic conditions thanks to its insight into optimal size and a rigorous and reliable design. LONGi will adhere to the product design concept based on the cost of electricity, pay attention to the application performance of the whole life cycle of the product, and continue to develop technologies and products with customer value.