（12） Hot spots and delamination
1. Photovoltaic module hot spot refers to a dark spot where the module is exposed to sunlight and some battery cells are blocked from working, causing the covered part to heat up much more than the uncovered part, resulting in excessive temperature and burning out.
2.The formation of hot spots in photovoltaic modules is mainly composed of two internal factors, namely internal resistance and the dark current of the cell itself. The hot spot durability test is a testing test to determine the ability of solar cell components to withstand the heating effect of hot spots. Detect solar cell components through reasonable time and process to demonstrate that solar cells can be used for a long time under specified conditions. Hot spot detection can be carried out using an infrared thermal imager, which can use thermal imaging technology to display the temperature and distribution of the measured target using a visible thermal map.
3. The temperature and time of delamination and lamination do not meet the standards.
Component impact:
1. Hot spots cause component power attenuation and failure, or directly lead to component burning and scrapping.
2. Delamination leads to component power attenuation or failure, which affects component lifespan and leads to component scrapping.
Preventive measures:
1. Strictly follow the repair SOP requirements and pay attention to the inspection after repair for 5 seconds.
2. The temperature of the soldering iron at the welding site and the control of the welding machine time should comply with the standards.
3. Regularly check whether the parameters of the laminating machine meet the process requirements, and conduct crosslinking degree experiments on time to ensure that the crosslinking degree meets the requirements of 85% ± 5%.
（13） EVA delamination
1. Unqualified crosslinking degree (such as low temperature of the laminating machine, short lamination time, etc.).
2. Foreign objects on the surface of raw materials such as EVA, glass, and backboard.
3. The uneven composition of EVA raw materials (such as ethylene and vinyl acetate) leads to the inability to dissolve at normal temperature, resulting in delamination.
Component impact:
1. Delamination can cause water to enter the interior of the component, causing a short circuit inside the component, resulting in component failure and scrapping.
Preventive measures:
1. Strictly control important parameters such as temperature and time of the laminating machine, and regularly conduct crosslinking degree experiments according to requirements. Ensure that the crosslinking degree meets the requirement of 85% ± 5%.
2. Strengthen the improvement of raw material suppliers and raw material inspection.
3. Strengthen the appearance inspection of finished products during the manufacturing process.
（14） Inefficient
1. Mix low-grade battery cells into high-end components (raw material mixing/or in-process mixing).
Component impact:
1. The overall power of the affected component decreases, and the power of the component decays significantly in a short period of time.
2. Low efficiency areas may generate heat and burn down components.
Preventive measures:
1. When placing battery cells in the production line, different grades of battery cells should be distinguished to avoid mixing. The grade of battery cells in the repair area should also be labeled to avoid misuse.
2. EL testers should strictly inspect to avoid the leakage of inefficient tablets.
（15） Silicone bubbles and gaps
1. Silicone bubbles and gaps are mainly caused by bubbles inside the silicone raw material or unstable air gun pressure.
2. The main reason for the gap is that the employees use non-standard adhesive techniques.
Component impact:
1. There will be rainwater entering the areas with gaps, and the heating of the components during operation will cause layering after rainwater enters.
Preventive measures:
1. Please ask the raw material manufacturer to improve and strengthen the IQC inspection.
2. The glue application techniques of personnel should be standardized.
3. After applying the glue, the personnel should perform their own actions and the cleaning personnel should strictly inspect it.
（16） Missing glue application
1. The personnel did not work seriously, resulting in missing glue.
2. The placement of production line components is not standardized, and personnel pull the wrong product into the next process.
Component impact:
1. Failure to apply glue can cause rainwater or moisture to enter and cause the connected components to catch fire.
Preventive measures:
1. Strengthen personnel skill training and enhance self inspection awareness.
2. The production line is strictly arranged according to the principle of "three fixed products" to avoid misuse.
3. Strictly inspect the cleaning components and packaging areas to avoid any defects or omissions.
（17） False soldering of leads
1. The personnel's operation techniques are not standardized or serious, resulting in missed welding.
2. The soldering iron temperature is too low, too high, or the welding time is too short, resulting in faulty soldering.
Component impact:
1. The component power is too low.
2. Poor connection leads to increased resistance, causing component damage due to ignition.
Preventive measures:
1. Strictly require operators to perform SOP operations and standardize their operational techniques.
2. Check the temperature of the soldering iron on time and standardize the welding time.
（18） Junction box silicone not cured
1. The silicone ratio does not meet the process requirements, causing the silicone to not solidify.
2. The glue hole A or B is blocked without glue, resulting in non curing.
Component impact:
1. Silicone non curing adhesive will flow out from the edge of the wire box gap, and the leads inside the box will be exposed to the air. In case of rain or moisture, it will cause electrical connection and cause the component to catch fire.
Preventive measures:
1. Strictly follow the regulations to confirm the drying action of the silicone surface every hour.
2. Regularly confirm whether the silicone ratio meets the process requirements.
3. The cleaning process should be strictly controlled to ensure that the silicone gel is 100% cured.
（19） EVA small bar turns yellow
1. EVA strips are exposed to the air for a long time, causing mutations.
2. EVA is polluted by flux, alcohol, etc., causing variation.
3. Chemical reaction occurs when used in combination with EVA from different manufacturers.
Component impact:
1. The customer does not accept the appearance defect.
2. It may cause delamination.
Preventive measures:
1. After opening, EVA should be strictly used up within 12 hours according to the process requirements to avoid prolonged exposure to the air.
2. Pay attention to the 5-second cleaning of the material placement area to avoid contamination during the processing.
3. Avoid using it with EVA from different manufacturers.
（20） Component color difference
1. The color difference of the component is caused by uneven coating during raw material processing.
2. The welding machine did not distinguish the placement of battery cells according to color during placement.
3. The repair area did not undergo color differentiation confirmation, resulting in mixed color differences.
Component impact:
1. Affects the overall appearance of the component and causes complaints.
Preventive measures:
1. Provide feedback to improve raw materials and conduct strict inspection and management of incoming materials.
2. The welding machine strictly requires color differentiation during feeding to avoid mixing.
3. Mark the color level of the battery cells in the repair area, and make your own actions during and after rework to avoid color differences caused by using the wrong cells.
（21） Power attenuation classification and detection methods
Photovoltaic module power attenuation refers to the phenomenon where the output power of the module gradually decreases with the increase of lighting time. The power attenuation phenomenon of photovoltaic modules can be roughly divided into three categories: the first type is the power attenuation of modules caused by destructive factors; The second type is the initial photoinduced attenuation of the component; The third type is the aging attenuation of components. The second and third categories are
Component impact:
1. The output power of the component gradually decreases.
Preventive measures:
1. Strengthen the quality control of unloading, transporting, and installing photovoltaic modules
2. The power attenuation test of photovoltaic modules can be completed through the I-V characteristic curve tester of photovoltaic modules.
（22） Reticular fissure
1. Hidden cracks refer to the appearance of small cracks in the battery cell, which can accelerate the power attenuation of the battery cell and affect the normal service life of the component. At the same time, hidden cracks in the battery cell can expand under mechanical load, potentially leading to open circuit damage and hot spot effect.
2. The occurrence of hidden cracks is caused by the combined action of multiple factors, such as uneven force on components or severe shaking during transportation and reshipment, which may cause hidden cracks in battery cells. Photovoltaic modules undergo EL imaging testing before leaving the factory, using an EL detector. The instrument uses the electroluminescence principle of crystalline silicon, and uses a high-resolution CCD camera to capture the near-infrared image of the module, to obtain and determine the defects of the module. The EL detector can detect whether solar cell components have hidden cracks, fragments, solder joints, broken grids, and abnormal phenomena of single cell batteries with different conversion efficiency.
Component impact:
1. Mesh cracks can affect component power attenuation.
2. The appearance of fragments and hot spots in the mesh cracks for a long time directly affects the performance of the components.
Preventive measures:
1. Avoid excessive impact of external forces on battery cells during the production process.
2. During the welding process, the battery cells should be insulated in advance (manual welding), and the temperature of the soldering iron should meet the requirements.
3. EL testing requires strict inspection requirements.
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