S-Bond has demonstrated the assembly (stringing) of photovoltaic (PV) solar panels bonding aluminum or copper buss bars using their active solders (S-Bond) in combination with thermosonic bonding. Thermosonic bonding is the simultaneous application of ultrasonic agitation, pressure and heat, normally applied using commercially available ultrasonic soldering irons.
Commercial polycrystalline silicon photovoltaic (PV) cells currently utilize an aluminum powder applied metallization as the current collector for the electrons released by the incident solar energy collects at the aluminized surfaces. Commercial PV cells then require that a conductor strip be bonded to the aluminized cell back in order to transmit the electrons (current) from the cell to the adjacent cells that make up a solar power module in a solar panel assembly. The challenge has been electrically bonding to the aluminized (or otherwise coated) PV materials. Many times silver paint / plated pads has been applied to the coated PV cell followed by conventional flux soldering of pre-tinned thin copper strip to the silver pad
The S-Bond active solder process eliminates the need for pre-coating of silver (lowering cost) to the coated cell surfaces and eliminates the need to use flux (lowering cleaning costs while improving the working environment with no flux off gases). The figures below show how thermosonic bonding of S-Bond coated copper (or even aluminum) buss strip can be used to “string” PV cells together into solar panel modules. S-Bond can provide S-Bond alloys tinned with Copper (or aluminum) buss using an ultrasonic solder pot as illustrated below. For aluminum powder metallized PV cells, the ultrasonic tip is used to “burnish” and densify the areas for buss strip attachment. This treatments makes a dense well adhered, directly S-Bond solderable surface. Using a heated ultrasonically activated soldering tip, the tip can be robotically manipulated to press heat and activate the S-Bond solder in order to locally reheat, reflow and mechanically disrupt the local oxides on the melting solders such that a metallurgical bond is made direct to the coated PV surfaces.
S-Bond has demonstrated this same thermosonic method for bonding to a range of different coated PV materials including Mo coated CIGS and even bonding ceramics to the back of concentrated solar PC cells (CPV’s). Contact us and see how S-Bond thermosonic boding might be used in your solar panel manufacturing processes. To see how robotics and thermosonic bonding can be integrated with robotics take a look at http://www.japanunix.co.jp/ju_en/products/video_unisonik.html .
Please Contact Us to inquire how S-Bond active solders and thermosonic bonding may be used in the manufacture your solar modules.