US-12622071-B2 - Bifacial PV module hybridized with III-V PV cells

Abstract

A hybrid photovoltaic (PV) module includes a bifacial PV module that has an upper sheet of glass, a lower sheet of glass arranged spaced apart and substantially parallel to the upper sheet of glass, and a plurality of PV cells sandwiched between the upper and lower sheets of glass. The upper sheet of glass has an outside surface on an opposite side from the plurality of PV cells. The hybrid PV module also includes a plurality of copper wires bonded to the outside surface of the upper sheet of glass so as to extend across a width thereof: a plurality of multijunction (MJ) PV cell assemblies positioned and bonded to the outside surface of the upper glass sheet, each MJ cell assembly of the plurality of MJ cell assemblies including an MJ cell, a secondary optical assembly and first and second conductive connectors, each being electrically and thermally connected to the MJ cell and to at least a respective one of the plurality of copper wires; and an upper lens array of a full size of the bifacial PV module and being attached in position there above.

Inventors

• James Roger P. Angel
• Nicholas DIDATO
• Joel BERKSON

Assignees

• ARIZONA BOARD OF REGENTS ON BEHALF OF THE UNIVERSITY OF ARIZONA

Dates

Publication Date

20260505

Application Date

20230421

Claims (3)

1. 1 . A hybrid photovoltaic (PV) module, comprising: a bifacial PV module comprising an upper sheet of glass, a lower sheet of glass arranged spaced apart and substantially parallel to said upper sheet of glass, and a plurality of PV cells sandwiched between said upper and lower sheets of glass, said upper sheet of glass having an outside surface on an opposite side from said plurality of PV cells; a plurality of copper wires bonded to the outside surface of said upper sheet of glass so as to extend across a width thereof; a plurality of multijunction (MJ) PV cell assemblies positioned and bonded to said outside surface of said upper glass sheet, each MJ cell assembly of said plurality of MJ cell assemblies comprising an MJ cell, a secondary optical assembly and first and second conductive connectors, each being electrically and thermally connected to said MJ cell and to at least a respective one of said plurality of copper wires; and an upper lens array of a full size of said bifacial PV module and being attached in position there above, wherein, when said hybridized PV module is oriented to face the sun, each lens of said upper lens array focuses direct sunlight onto a respective one of said plurality of MJ cell assemblies while transmitting diffuse light to said bifacial PV module, and wherein said copper wires and connectors are structured to provide at least two functions, namely to: conduct electrical power of said MJ cells to a perimeter of said hybrid PV module and thence via additional electrical wiring to an external circuit, and conduct and spread heat from said plurality of MJ cell assemblies across said upper sheet of glass of said bifacial PV module so that the module serves as a heat sink for said plurality of MJ cells assemblies thereby providing passive convective cooling from said lower sheet of glass and thus preventing overheating and increasing optical to electrical conversion efficiency, without incurring an added complexity and cost of added heat sinks or active cooling and parasitic electrical power loss.
2. 2 . The hybrid PV module according to claim 1 , wherein each copper wire of said plurality of copper wires have at least one of a square or rectangular cross section, are untwisted, and have one of their four sides bonded to the outside surface of said upper sheet of glass with a thin layer of thermally conducting adhesive, and wherein heat transfer from each copper wire of said plurality of copper wires to said bifacial module is maximized.
3. 3 . The hybrid PV module according to claim 1 , further comprising mirrored side panels attached to edges of said upper lens array and of said bifacial module, said side panels being arranged to reflect additional diffuse light onto said bifacial PV module.

Description

CROSS-REFERENCE OF RELATED APPLICATION This application is a U.S. National Stage of PCT/US2023/019423, filed Apr. 21, 2023, which claims priority to U.S. Provisional Application No. 63/333,943 filed Apr. 22, 2022; the entire contents of which are hereby incorporated by reference. BACKGROUND 1. Technical Field The field of currently claimed embodiments of this invention relates to photovoltaic (PV) modules, and more particularly to bifacial PV modules adapted for higher conversion efficiency by the addition of multijunction PV cells and glass lens arrays. 2. Discussion of Related Art A photovoltaic (PV) module is a device to convert sunlight and daylight into electricity. PV modules typically are made with a glass sheet supporting and protecting a thin layer of semiconductor material, commonly silicon. For utility scale generation they are typically turned about a horizontal axis through the day to face the sun as it moves across the sky. In some cases, silicon PV cells are sandwiched between two glass sheets to form a bifacial module which converts reflected sunlight from behind as well as direct and diffuse sunlight from in front. They are limited in their conversion efficiency of sunlight energy into electricity because they commonly use only one semiconductor type, and hence convert only a part of the solar spectrum. Conversion efficiency of PV cells may be much increased by use of tandem or multijunction (MJ) cells, in which a stack of two or more different types of semiconductor collectively harvest energy more efficiently across the full solar spectrum, and also by concentrating the sunlight on the cells. Thus, the best tandem silicon-perovskite PV cells have been measured with 32.9% efficiency in non-concentrated sunlight, and the best 4-junction cells at 665× concentration at 47.6% (NREL, 2022, Best Research Cell Efficiency). MJ cells are more expensive, per unit area, than the silicon cells used in most PV modules. However, they become less expensive, per unit of electrical power generated, when greatly reduced in size and powered by concentrated spots of focused sunlight. But in the past, PV modules using multijunction cells under concentrated sunlight have not realized enough increase in energy output to offset their additional costs. To date, no company has been able to exploit multijunction PV cells under concentrated sunlight to successfully compete commercially in large scale generation with existing directly illuminated PV modules that are manufactured in huge volume at low cost, and with the full advantage of economy of scale. In some recent related art, test modules using multijunction cells under focused sunlight have obtained somewhat improved conversion efficiency by incorporating additional silicon cells. In these hybrid modules, the silicon cells convert into electricity the energy of diffuse light, which is not focusable. The separation of diffuse and direct sunlight is made by lenses that focus direct sunlight onto the multiple multijunction cells while also transmitting diffuse light to full-area PV cells. The types of lenses commonly used in prior art are Fresnel and plastic lenses, (Lee et al., “Concentrator photovoltaic module architectures with capabilities for capture and conversion of full global solar radiation”, PNAS Dec. 5 2016), Meitl et al, 2013, US 2013/0182333 A1. However, these lenses are not highly transmissive for either direct or diffuse light. The complexity and cost of these prototype hybrid modules has prevented commercial adoption. In a prior art invention, PCT/US2020/052522, Apparatus and Method for the Manufacture of Large Glass Lens Arrays, the entire content of which is incorporated herein by reference. Angel et al describe methods for forming highly transmissive arrays of conventional (not Fresnel) glass lenses. In one of these methods, flat or cylindrical molds are used to emboss arrays of adjacent plano-convex spherical lenses. FIG. 1 illustrates rollers 15 (upper) and 16 (lower) to emboss a continuous glass sheet. However, a potential difficulty identified with molding a parquet of lenses is entrapment of gas at the crown of the inverted concave cups, as soft glass is pressed up into each cup to form the crown of the lens surface. Thus, there remains a need for approaches for PV modules using such arrays that can provide higher conversion efficiency, and that can be cost effective for generation at commercial and utility scale. SUMMARY A hybrid photovoltaic (PV) module according to some embodiments of the current invention include a bifacial PV module that has an upper sheet of glass, a lower sheet of glass arranged spaced apart and substantially parallel to the upper sheet of glass, and a plurality of PV cells sandwiched between the upper and lower sheets of glass. The upper sheet of glass has an outside surface on an opposite side from the plurality of PV cells. The hybrid PV module also includes a plurality of copper wires bonded to the outside surfa