Technology

Entering the "gigawatt era" of solar manufacturing depends on making correct choices in two areas: 1: materials technology (solar cell type)  and 2: manufacturing technology that can sustain profitablility over the long term. Choosing the right  manufacturing technology is what enables taking full advantage of the material technology. These two elements must not only have  high efficiency and low cost, but also the ability to achieve high throughput and to be inherently reliable. Choice of the right combination of manufacturing technologies for CIGS is what sets Siva Power apart.

 

Siva's co-evaporated CIGS and MLI glass architecture provides the best combination of material technology and manufacturing technology. The benefit of Siva’s approach include:

 

1) highest efficiency thin film that now is on par with mc-Si

 

2) lowest cost enabled with fast deposition, high capacity tools, and low cost raw materials, with the fewest manufacturing steps (~1/2 of singulated cell approaches)

 

3) inherently reliable; avoids deleterious mechanical and metallurgical bonds as found with singulated cells

Material Technology

 

Three-stage co-evaporation of CIGS has been proven world-wide at leading institutes such as NREL, ZSW, EMPA, and HZB to be the ideal method to deposit CIGS.  Attributes of three-stage evaporation include:

 

  • High rate deposition: the CIGS layer forms directly without the need for lengthy reactions or atomic re-arrangement
  • Lowest cost raw materials: co-evaporation uses simple metal pellets, the lowest value-add state.
  • Highest efficiency: the film has a period where it becomes liquid, promoting liquid phase epitaxial growth of large, defect-free grains.

Manufacturing Technology

 

Key to low-cost manufacturing is monolithic integration (MLI), a process that cells using a series of automated laser scribes. MLI substantially reduces the manufacturing steps in half compared to singulated cell approaches

 

Our module uses two square meter glass. The large format glass improves bankability by providing a drop-in replacement for mc-Si.  MLI avoids mechanical/chemical connections found in Si and cell-based CIGS eliminating the possibility for premature failure due to corrosion or mechanically stress, the predominant factors in pre-mature field failure of cell-based CIGS.  MLI on glass also does not require diodes (a significant cost for stainless steel-based CIGS cell technology).