Solar Module lamination problem analyse

1.The possible causes of fragmentation in modules:

①. The cells are crushed when vacuumizing because the soldering process is not smooth,existing piles of tin or metallic inclusion.

②. Originally, the cells have defects.Laminate too early which EVA also has good liquidity.

③. When lifting the modules, the gesture is unreasonable and both hands have pressed the cells.

④. The pressure is too high: reduce the pressing speed, increase the thickness of the EVA,use the EVA with the depth of the embossing

⑤. Reduce the thickness of the ribbon

2.The possible causes of bumps in modules:

①. EVA has been cut and placed too long which causes it wet.

② The material of EVA is not pure. Use the embossed EVA

③ The time of vacuum is too short and the pressure cannot drive away the bumps. Check the vacuum degree, pumping rate, and speed up the pressing speed of the EVA

④ The pressure of lamination is not enough. Check the sealing ring of the laminator

⑤ The temperature of the heating plate is inhomogenous so that part of the eva is cured in advance.

⑥ The lamination time is too long or the temperature is too high, so that the organic peroxide is decomposed and produce oxygen.

⑦ There are other things and the wetting angle is over 90° so that there is gas next to the foreign things.

⑧ The influence of flux: reduce the use of flux or change flux.

⑨ Thickness of the bus bar in the middle of the half-piece MBB module.The bubbles in the 0.35mm bus bar are more likely bigger than in the 0.25mm bus bar.

⑩ Barcode blister, barcode damp.

⑪ Bus bar blisters

⑫ After the destroy of the laminated layer,the residual glass is not cleaned up and the silicon plate is broken

3. Which there are hairs and garbage in the modules may be caused by:

① Because EVA, DNP and small cars have static electricity,sucking the floating hair, dust and small garbage to the surface.

②When the layout,the people works above the modules and cannot guarantee the body doesn’t exist hair and garbage.

③ Some small insects fly into the modules.

④ In winter, the humidity of the workshop isn’t up to standard,causing hair fall into the modules.

4. Which the bus bar warps inward may be caused by:

① During the lamination, more gas will gather at the bus bar. Laminating the rubber plate to press the gas out of the module, and that part of the interstitial should be filled by EVA with better fluidity. This flow of EVA bends the originally straight bus bar.

② The shrinkage of EVA.

5. Which the backsheet of the module is uneven or wrinkled may be caused by:

①. Excess EVA will stick to high-temperature cloth and backsheet.

② EVA shrinkage: shorten the vacuum time, reduce the lamination temperature, and change the cutting direction of EVA

③ . backsheet shrinkage: change the backsheet

④. plicated ribbon: smooth the ribbon6

Solutions:

1. There are fragments in the module:

①. Firstly, check the soldering quality in the soldering area, and carry out some targeted training for employees to make the soldering complete at one time.

②. Adjust the lamination process, increase the vacuum time and reduce the lamination pressure (adjust by the lamination time).

③. Check all process and optimize the gesture of the laminating person.

2. bumps in modules:

① Control the quantity of EVA every day and let every employee know the daily produce

② The material is determined by the manufacturer, so try to choose better materials.

③ Adjust the lamination parameters to make the vacuumizing time appropriate.

④ Increase the lamination pressure. (it can be adjusted by laminating time and also achieved by putting a high-temperature cloth).

⑤ Put a high-temperature cloth to make the module heaten evenly. (the maximum temperature difference is less than 4°).

⑥ Determine the total lamination time according to the parameters provided by the manufacturer to avoid long time.

⑦ Pay attention to 6S management especially the layup and try to avoid falling in foreign matters.

⑧ In the half-piece of module,select the appropriate EVA size.

3. There are hairs and garbage in the modules:

① Do good 6S management, keep the surrounding working environment clean and tidy and wash clothes frequently

② Adjust the technology, optimize the operation of the layup process, and let two people take the materials.

③ Close the door and install mosquito killing lamps to reduce small insects flying into.

4. Bus bar warps inward:

① Adjust the lamination parameters, lengthen the vacuum time and reduce the lamination pressure.

② Choose better materials.

5. The backsheet of the module is inhomogenous:

① Purchase good backsheets.

② Clean the high-temperature cloth every time and clean the residual EVA on the rubber plate in time.

③.The viscosity of glass and backsheet is not good

6. Laminated modules turn yellow

① The lamination temperature is too high: shorten the lamination time or reduce the lamination temperature

7. The viscosity of glass and backsheet is not good

①. Heating temperature is not enough: increase the lamination time and check the temperature of the heating plate

② . Stained glass: clean the glass

③. Replace EVA: check the storage condition and expiration date of EVA

④. The lamination temperature is too high: shorten the lamination time or reduce the lamination temperature,and check the temperature of the heating plate

⑤. Influence of backsheet’s surface: replace the backsheet

8. The shrinkage of the EVA film at the edge of the module

①. The shrinkage of EVA film is too large: add additional EVA film at the edge, increase the size of EVA film and shorten the vacuum time

9. Don’t use the colored sealant

① This pigment will slowly diffuse into EVA in the cell, and the cell will change color after one year.

10. The vacuum degree of laminator decreases

①. The vacuum pump oil begins to be muddy or dirty.This requires changing the oil and cleaning the vacuum pump.At the same time,clean the litter in the vacuum pump.

②. Check whether the vacuum pump doesn’t have oil.

③. Replace the connected vacuum hose. After the high temperature of the laminator, peroxide (crosslinked catalyst),antioxidant and little wax acid in EVA will come back with the increase of temperature. Some peroxides participate in the crosslinked chemical reaction of EVA, form new things  and escape into the air. With the higher working temperature of the laminator, the more and the more complex substances in EVA escape into the air. Some of these complex substances are sucked into the vacuum pump, adsorbed on the modules in the vacuum pump or dissolved in the vacuum pump oil, resulting in the decline of the function of the vacuum pump. With the decrease of the temperature,the other part in the vacuum pipe forms colloidal particles and land on the vacuum pipe. Over time, the vacuum pipeline will become narrower or even blocked.

11. The laminated modules have displacement

① Stick more 3M tape at the displaced place

② Use a soldering iron to point the cell at the displaced place for several times

③ because of EVA shrinkage, test EVA shrinkage

④ The layout is not well arranged

⑤ String is crooked. Fix with 3M during layout

⑥ The position of modules should be consistent with the direction of long shrinkage rate of silicon plate

⑦ The time of vacuum should not be too long

⑧ The silicon plate of the laminator is loose

⑨ Inflation speed of laminator

12: What is the reason of the overflow of the EVA?

1. If it is ARC glass, it is best to put a cellophane and remove it when edge cutting. This will not destroy the film of glass.

2. In the first cut,EVA should not be too long but left a little.

3. The main reason is that the heating plate may be locally inhomogenous. If EVA is softened and has fluidity during heating,some will flow to the inhomogenous place or flow under the glass.EVA will stick to the glass after pressurization.

4. The reason of EVA overflow is that its fluidity is good. We have shorten the door width to reduce the overflow.