During the production and transportation of photovoltaic modules, no matter how careful one is, cracks and damages cannot be avoided. These cracks and damages are caused by irregular surface stresses caused by external forces during welding or transportation.
When there is a rapid increase in temperature in a low temperature environment over a short period of time without preheating, a temperature difference occurs between the inner and outer surface and this expansion leads to cracks. Sometimes the instantaneous high temperature during welding can also cause cracks.
The following measures can be taken to prevent the formation of these hidden cracks in photovoltaic modules:
- During the production process, situations where there is a risk of compression and collision by external forces should be avoided. During transportation, the force should be distributed as much as possible and uneven stresses should be avoided.
- Before welding, the temperature of the photovoltaic module should be increased slowly and sudden heating should be avoided.
- During EL testing, one should strictly analyze the thin black stripes that appear in the images, identify the cause of the problem and try to eliminate the risk of hidden cracks.
- When hidden cracks are detected in the image, the backplate and EVA material should be opened for verification. If possible, repeated verification should be carried out using a flashlight. Photovoltaic modules with hidden cracks should be replaced immediately.
Photovoltaic module cracking is a common problem and the challenge is to prevent cracks as much as possible, reduce the probability of cracking and improve the quality of the manufacturing process of modules.