（1） Snail pattern
1.The appearance of snail lines is a comprehensive process, and factors such as additives in EVA film, silver paste composition on the surface of battery cells, hidden cracks of battery cells, and catalysis of water in the system can all promote the formation of snail lines. The appearance of snail lines is not inevitable, but has its accidental triggering factors. The EVA film formula includes crosslinking agents, antioxidants, coupling agents, and other additives. The crosslinking agent generally uses peroxides to initiate the crosslinking of EVA resin. As peroxides are highly active initiators, if there is still a lot of residue in the crosslinking agent after lamination, it will have an initiating and accelerating effect on the production of snail patterns.
2. The additives used in EVA film have purity indicators, and generally, the purity requirement should be above 99.5%. The impurities in the additives mainly consist of by-products and residual additives during synthesis, which exist in small molecule states with high boiling points and cannot be removed from the system through lamination vacuum extraction. Therefore, if the purity of the additives is not high, these impurities will also affect the stability of the EVA film and may cause the appearance of snails.
Component impact:
1. The pattern generally accompanies the appearance of hidden cracks in the battery cells.
2. The surface of the battery cell is oxidized.
3. It affects the appearance of the component.
Preventive measures:
1. Use additives that meet the purity indicators for VA adhesive film.
2. Have sufficient understanding of the handling of components during installation.
（2） 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.
4. Too much flux will cause delamination along the main grid line when encountering high temperature in the outside for a long time.
Component impact:
1. A small delamination area affects the high-power failure of the component. When the delamination area is large, it directly leads to 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, and control the crosslinking degree within 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.
4. Strictly control the amount of flux and try not to exceed 0.3mm on both sides of the main grid line.
（3） Poor silicone leads to delamination and hidden cracks in battery cell intersections
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. There is a gap in the border gluing, and after rainwater enters the gap, the component heats up during long-term operation, resulting in delamination of the component edge
4. The battery cells or components are cracked due to external forces.
Component impact:
1. Layering can lead to water ingress inside the component, causing internal short circuits and component scrapping.
2. Cross cracking can cause fragmentation and cause battery failure, and the power attenuation of the module directly affects the performance of the module.
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.
2. Strengthen the improvement of raw material suppliers and raw material inspection.
3. Strengthen the appearance inspection of finished products during the manufacturing process.
4. The final assembly gluing requires strict operation techniques, and the silicone needs to be completely sealed.
5. Avoid collision with external forces when lifting and placing components.
（4） Component burnt out
The contact area between the busbar and the welding strip is small, or the resistance increases due to faulty welding, resulting in heating and component burning.
Component impact:
1. There is no impact on the component in a short period of time, and the component will be burned out and eventually scrapped when working on an external power generation system for a long time.
Preventive measures:
1. In the welding and component repair processes of the busbar, it is necessary to strictly follow the requirements of the operation manual for welding to avoid the welding area being too small during the welding process.
2. After welding, it is necessary to visually inspect whether the welding is OK.
3. Strictly control the soldering iron issue within the control range (375 ± 15) and the welding time for 2-3 seconds.
（5） Component junction box on fire
1. The lead wire is not tightly clamped in the card slot, causing a spark.
2. The welding area of the leads and junction boxes is too small, resulting in excessive resistance and causing ignition.
3. If the lead wire is too long and comes into contact with the plastic parts of the junction box, prolonged heating can cause a fire.
Component impact:
1. The fire directly causes the component to be scrapped, which may lead to a serious fire.
Preventive measures:
1. Strictly follow the SOP operation to fully insert the lead wire into the card slot.
2. The welding area of outgoing line and junction box shall be at least greater than 20 square millimetre.
3. Strictly control the length of the lead wire to meet the requirements of the drawing, operate according to SOP, and avoid the lead wire from touching the plastic parts of the junction box.
（6） Battery split
1. Improper operation during the welding process caused cracks.
2. Improper lifting and placement by personnel resulted in component cracking.
3. The lamination machine has malfunctioned with component chips.
Component impact:
1. Partial failure of the split affects the power attenuation of the component.
2. The power attenuation or complete failure of a single battery cell affects the power attenuation of the component.
Preventive measures:
1. The welding and rework area of the busbar shall be strictly operated according to the SOP method.
2. Personnel shall strictly follow the process requirements when lifting and placing components.
3. Ensure regular maintenance of the laminating machine. Every time equipment parts are replaced, the first article confirmation must be strictly done before production.
4. Strictly control and inspect EL testing to prevent any defects or omissions.
（7） Too much battery flux
1. The welding machine is adjusted to spray too much flux.
2. Personnel apply too much flux during repair.
Component impact:
1. EVA delamination at the position of the main grid line of the affected component.
2. After a long time on the power generation system, the components appear lightning black spots, which affect the power attenuation of the components, reduce their lifespan, or cause them to be scrapped.
Preventive measures:
1. Adjust the amount of flux sprayed by the welding machine and conduct regular inspection.
2. When replacing the battery chip in the repair area, please use the designated soldering pen. It is forbidden to apply flux with a big brush.
（8） False soldering, over soldering
1. Too much welding temperature or too little or too fast application of flux will lead to faulty welding.
2. Excessive welding temperature or welding time can lead to over welding.
Component impact:
1. False soldering can cause delamination between the solder strip and the battery cell in a short period of time, affecting the power attenuation or failure of the component.
2. Overwelding causes damage to the internal electrodes of the battery cells, directly affecting the power attenuation of the components, reducing their lifespan, or causing them to be scrapped.
Preventive measures:
1. Ensure the parameter settings of welding machine temperature, flux injection amount and welding time, and check regularly.
2. Ensure the temperature of soldering iron, welding time and use correct soldering pen to apply flux in the repaired area.
3. Strengthen EL inspection efforts to avoid defective products missing from the next process.
（9） Welding strip offset or warped fragments after welding
1. Abnormal positioning of the welding machine can cause the welding strip to shift.
2. The deviation of the main grid line of the battery raw material will cause the welding strip to deviate from the main grid line after welding.
3. The temperature is too high, and the bending hardness of the welding strip is too high, resulting in the bending of the battery cells after welding.
Component impact:
1. Offset can lead to reduced contact between the welding strip and the battery area, resulting in delamination or affecting power attenuation.
2. Overwelding causes damage to the internal electrodes of the battery cells, directly affecting the power attenuation of the components, reducing their lifespan, or causing them to be scrapped.
3. Bending after welding causes fragments of battery cells.
Preventive measures:
1. Regularly check the positioning system of the welding machine.
2. Strengthen the incoming inspection of raw materials for battery cells and solder strips.
（10） Component tempered glass explosion and wire breakage in the junction box
1. The component was severely impacted by external forces during transportation, resulting in glass explosion.
2. There are impurities in the glass raw material that cause the raw material to self explode.
3. The wire was not placed in the specified position, resulting in back pressure damage to the wire.
Component impact:
1. Glass blasting components are directly scrapped.
2. Wire damage leads to component power failure or the risk of leakage and power connection accidents.
Preventive measures:
1. During the lifting and placing process, the components should be handled gently to avoid being collided by external forces.
2. Strengthen the inspection and testing of glass raw materials.
3. The wires must be strictly coiled according to the requirements to avoid scattering on the components.
（11） Bubble generation
1. If the vacuum temperature time of the laminator is too short, and the temperature setting is too low or too high, bubbles will appear.
2. If the interior is not clean and there are foreign objects, bubbles may appear.
3. If the size of the insulation strip is too large or too small, it can cause bubbles.
Component impact:
1. Component bubbles can affect delamination. Severe damage can lead to scrapping.
Preventive measures:
1. The temperature parameters for the vacuum pumping time of the laminating machine should be strictly set according to the process requirements
2. Welding and stacking processes should be cleaned within 5 seconds.,
3. The cutting size of the insulation strip is strictly required for cutting and inspection.
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