Invention:
This invention is a new type of hybrid PV module that overcomes previous deficiencies of light loss and prohibitively high manufacturing cost. It takes a complete manufactured bifacial PV module as its starting point, which has single-junction PV cells sealed between thin glass windows. This module serves not only to harvest the energy of diffuse light, but also to carry and cool an array of small multijunction, III-V PV cells to harvest direct sunlight with very high conversion efficiency. The small cells are mounted to the module’s front window on small copper/ceramic substrates. An array of lenses molded into a single sheet of glass is attached to the front of the apparatus to concentrate direct sunlight onto each of the MJ cells while transmitting diffuse light to the single junction cells. A very fast molding process for manufacturing the lens arrays is described in which relatively cold molds are used to form the lenses into a sheet of hot, soft glass. To maximize optical coupling efficiency and provide tolerance to wrong pointing, the concentrating optics include a second spherical glass lens and flat glass plate bonded to the MJ cell. Electrical power from the MJ cells is conducted to the edge of the module by copper wires attached also to the entrance window. In this invention, cooling of the multijunction cells, as needed to maintain their high conversion efficiency, is accomplished by conduction of heat through the base module’s glass window. To maximize the heat flow, copper wires attached to the III-V cells are configured to conduct away heat as well as electrical power. Thermally conductive adhesive is used to bond these wires, as well as the cell substrates, to the glass window.
Background:
Multijunction PV cells can now be made to convert sunlight with twice the efficiency of standard silicon modules. Despite hundreds of millions of dollars invested, no company has yest succeeded in commercializing this advantage. This invention builds on existing products and knowledge of the PV industry, advancing innovation in the renewable energy sector.
Applications:
- Solar arrays of all forms
- Affordable renewable energy
Advantages:
- Fast molding process of array lens
- Higher efficiency
