Why Can't 1.3m Wide Modules Resist Hail?
As a power generation facility installed outdoors, photovoltaic modules need to have sufficient reliability to withstand the test of various extreme weather such as hail. At the same time, in order to reduce losses caused by natural disasters, most owners will purchase power plant property insurance as a guarantee. However, it is not safe to sit back and relax with insurance. If the components are too large to resist the impact of hail, the owner will ultimately pay for the loss. Why do you say that?
In the hail test, the part of the module in direct contact with the hail is the glass on the upper surface. Therefore, glass is a key factor in determining the impact resistance of components. Once the glass is broken, the component loses the most important layer of the barrier, and its mechanical load and resistance to decay are greatly affected. When the glass is subjected to an external stress impact greater than the breaking strength, the glass will produce micro-cracks and lead to breakage.
On the one hand, the increase of glass width will lead to the weakening of tempering properties, and the surface prestress of super large modules is 10% lower than that of conventional modules. The prestress is not enough to offset the impact of external stress, and the ability of the component edge to resist hail is significantly reduced. On the other hand, from the perspective of the size effect, the larger the glass size, the higher the probability of having microcracks. And the literature shows that under the same hail impact conditions, the long side of the glass bears more stress than the short side, and the micro-cracks expand rapidly under the action of external stress. The weaker breaking strength of the oversized component meets the greater stress, resulting in a great risk of glass shattering.
On the other hand, going back to the issue of power plant property insurance, if you take it for granted that the reliability of the components is less and the impact resistance of the glass is weaker, it doesn’t matter. In case of damage, the insurance company will pay. It may be that when the power station really encounters a hailstorm, the assets will also face a catastrophe at the same time. Because power station property insurance mainly guards against losses caused by natural disasters such as earthquakes and hurricanes, risk assessment of hail disasters is rarely performed.
To sum up, the size of the component is directly related to its anti-hail impact ability, and the component size should have a reasonable limit. Blindly increasing the size will lead to a decrease in product reliability. Once it cannot bear the impact of hail, it will bring huge losses to the power station owner.
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