With its own manufacturing unit and thin-film technology, HHV is ready to surge ahead in the Indian and global market; both its production line as well as its product are seen as very novel in the new thin-film sector. This facility has the capability to produce Thin-Film Solar PV Modules, in compliance with IEC and UL standards for photovoltaic design and safety.
HHV has a workforce of over 300 employees in a plant which sprawls across 80,000 square feet plant in Dabaspet, 50 kilometers from Bangalore. It is India’s first manufacturing company to have automated production lines of thin-film amorphous silicon (a-Si) PV modules. More than 10 years of research have gone into making the module/manufacturing technology pioneered by HHV. In its entry into the global solar photovoltaic market, HHV Solar has leveraged on the expertise and reputation of its parent company, HHV (Hind High Vacuum Company Pvt. Ltd)
HHV’s factory has an annual capacity of 10 Megawatts, and it makes SPV glass modules one square meter in size and a peak power output of 60 Watts.
HHV also offers installation of its production line at factories willing to manufacture thin-film solar PV modules. The company helps its customers with installation at the customer’s facility, module design, applications support, and access to HHV’s advanced technology research base.
The international popularity of HHV’s technology can be seen in how it newly signed a JV Partnership MOU with Canada based Solar Source Corp (SSC) to build Canada’s first amorphous silicon (thin film) solar panel manufacturing facility, to be based at Summerside, Prince Edward Island (PEI).
In MIT’s Technology Review India, Srinivas Rao and Vantika Dixit cover HHV’s unique a-Si thin-film solar module manufacturing process:
In the entire production line , there are four rounds of laser scribing.
As a first step, a glass sheet coated with transparent conducting oxide (TCO) is put through laser scribing. (The TCO material has a haze and therefore when used in solar modules it helps in trapping more sunlight into the cell.)
In the scribing process the laser marks a line on the coated glass, separating each thin-film layer into a multiple number of single-cells.
After the completion of the first round of scribing, the coated glass undergoes cleaning before entering the most important process of the entire production line: the plasma enhanced chemical vapor deposition system. The PECVD has been designed to deposit the amorphous silicon thin-film on the coated glass through chemical vapor. The system deposits three layers of a-Si: P-type doped amorphous silicon, intrinsic amorphous silicon, and N-type amorphous silicon. The PECVD system consists of 14 chambers assembled one after another with isolation chambers in between to minimize the contamination of different gases. Throughout the process, two glass sheets travel in pairs on two rails arranged parallel to each other. After the initial process of 84 minutes, the system can produce two a-Si modules every six minutes.
The second laser scribing is done after the a-Si deposition is done.
The a-Si glass sheets then go through a direct current (DC) magnetron system which deposits electrical contacts on the sheets. The glass sheets are horizontally placed on vacuum compatible conveyor belt that pushes them into the magnetron system, which deposits zinc oxide and aluminum for providing contacts to transmit the electric current.
The third scribing is done after the deposition of the back electrical contacts.
The last of the four stages of laser scribing is an ablation process which removes the complete thin-film layer build up around the edge of the module.
The module is subsequently moved to tabbing. The tabbing process attaches conductive strips to the solar cells. The one-minute process is carried out simultaneously on both sides of the module.
Before the thin-film modules are framed for installation, they go through photovoltaic lamination. HHV’s PV laminators are capable of encapsulating several modules at a time, significantly reducing the cycle time and increasing productivity.