Product Briefing Outline: Meco Equipment Engineers has developed its Cell Plating Line (CPL) for the metallization of crystalline solar cells to enable a fine line and thin seed layer of silver paste to boost cell efficiencies for volume production applications.
Problem: Currently frontside metallization of crystalline solar cells is done by screen printing a thick-film Ag paste. Typically, these screen-printed contact fingers are up to 120μm wide to obtain sufficient electrical conductance. To further increase the cell efficiency, the contact finger width can be reduced as the active area of the cell increases (less shading). However, cell efficiency improvement is limited as the poor aspect ratio of screen printed contact fingers leads to an increase of the finger resistance value at the same time.
Solution: The CPL process starts on a fine line and thin seed layer of silver paste where the electrical conductance of the contact finger is further enhanced by electroplating either Ag or Ni-Cu-Sn onto it. This gives a fine-line contact finger while the resistance value is also improved at the same time. This leads to cell efficiency improvements of 0.3–0.5% and additionally the consumption of costly Ag paste can be reduced dramatically. For the production of next-generation solar cells where the SiN layer has been opened by laser, the CPL process can be used as a direct metallization process onto silicon. In this case, even higher cell efficiency improvements are feasible.
Applications: Metallization of silicon solar cells; frontside or backside plating. Also simultaneous front and backside plating possible (e.g., for bifacial cells).
Platform: The CPL is a turnkey line for plating of Ag or Ni-Cu-Sn. The output is either 1500 or 3000 cells/hour, although it can also be tailored to specific needs. The CPL is delivered with automated cell loading/unloading (either stack-to-stack or cassette loading). As the cells are vertically transported through the CPL, the drag over of chemistry is considerably lower than in case of horizontal cell transportation. The advantages are evident: a very low consumption of chemicals and a strongly reduced amount of wastewater.
Availability: Currently available.
