The wafers produced in wafer manufacturing are processed further to solar cells. For this purpose, the wafers are doped and surface-treated so that the cells can later convert solar energy into electrical energy. Generally, phosphorous is diffused in the wafers to create the p-n junction. After the edges have been insulated, the plasma coating process gives the cells their signature characteristic blue color.
Then electrical contacts are applied to both the front and back of the cells using a screen printing process. These contacts are later used to conduct the electricity generated out of the cells.
High output quantities
Cell manufacturing also requires handling cycle times of less than one second. Because of the high acceleration rates, the grippers must apply high holding and shear forces. What’s more, the wafer gripper SWGm can integrate inspection and testing tasks during handling by using the optional integrated sensors.
Low breakage rates
The breakage rate of the processsignificantly affects the output quantities. For that reason, there is a high focus on handling the cells as gently as possible. The special gripper SWGm enables minimum breakage rates compared to other handling technologies. The large contact surface and low vacuum level mean that the gripper generates only minimum surface pressure, making it particularly gentle.
Contamination of the cell surfaces must be avoided throughout many processes in the production chain. Because marks or contaminations have a negative effect on the chemical processes, particularly before the plasma coating process. The wafer gripper SWGm with a contact surface made of contamination-free PEEK material is the optimal solution. Suction cups made of the markless material HT1, can also be used in cell manufacturing.
Separating the cells
Separating the cells places high demands on the gripping technology. The floating suction cup SBS generates a high flow rate, which is used to achieve a larger engamenet distance to separate the cells. The optional floating suction cup modules SBSm, which can be integrated into the wafer gripper SWGm, allow the advantages of the wafer gripper to be combined with the engagement distance of floating suction cups. Sensors on the wafer gripper SWGm not only allow coverage monitoring, distance measurements and breakage detection, but also detect when two cells have been picked up. Detecting double layers during destacking processes reduces cycle times considerably.