1. The battery is hidden cracked
Reason:
A. The battery is caused by external forces during welding or transportation.
B. The battery has not been preheated at low temperature and suddenly suffers from high temperature in a short period of time, causing hidden cracking phenomenon.
C. The instantaneous temperature during welding is too high.
Preventive measures:
a. In the production process to avoid battery too much external force collision.
b. During the welding process, the battery should be insulated in advance, and the temperature of the soldering iron should meet the requirements.
The c. EL test rigorously analyzes the thin lines of black bands on each image.
d. When there is a hidden crack, open the backplane and EVA, and confirm with a flashlight. Hidden segments should be replaced in time.
2. EVA is not dissolved
Reason:
A. EVA material expired.
B. The heating process of the laminating machine (such as low temperature of the laminating machine, short laminating time, etc.) is unreasonable.
C. The crosslinking degree test can not find out the correct process parameters of the EVA.
Preventive measures:
a. Strengthen the improvement of raw material suppliers and raw material inspection.
b. Strictly control the temperature, time and other important parameters of the laminating machine.
c. Perform cross-linking degree test according to the requirements, and control the cross-linking degree within 85%±5%.
d. Different manufacturers of materials use different process conditions.
3. Bubbles
Reason:
A. There are foreign bodies in the components.
B. The EVA expires.
C. Laminating machine failure: low vacuum, seal ring cracks.
D. The parameters of the laminator are incorrectly set.
E. Residual flux surface.
F. Virtual welding of the interconnection bar.
Preventive measures:
a. Improve the workshop production environment and check before laminating.
b. The EVA used should be kept within the shelf life, and those that cannot be used up should be sealed and stored.
c. Adjust the parameters of the laminating machine when a large area of bubbles bursts.
d. Do a spot check on each shift of the laminating machine, observe the upper and lower vacuum values in time, check the seal status in time, and do daily maintenance.
e. EVA of different manufacturers have different laminating parameters, adjust the process in time.
f. Control the use of flux and scrub the surface with alcohol when residual.
g. As far as possible, reduce the repair of the battery on the stacked platform to prevent foreign matter from falling into and eliminate secondary pollution.
h. The management personnel confirm the process value set by the laminating machine every day.
4. Black film
Reason:
A. The positive and negative interconnection bar is short-circuited.
B. Virtual welding of interconnecting strip.
C. The junction box diode is welded back or the connection is abnormal.
D. External cables to the test machine are abnormal.
Preventive measures:
a. Prevent residual solder on the edge of the battery during serial welding.
b. Prevent virtual welding when the temperature is low.
c. Focus on image inspection during initial test.
d. After the final test abnormal to break the frame and change the film.
e. Check junction box diode welding and lead welding when black.
f. Check the external cables of the test machine.
