Multiple solar cell and method for manufacturing the same

#The invention relates to a multi junction solar cell, comprising a substrate like a Ge or GaAs substrate as well as a solar cell structure comprising several subcells deposited on the substrate, wherein the substrate has peripheral side faces and the solar cell structure has a peripheral circumferential surface which runs spaced apart from the side faces.

#The invention also refers to a method for producing a multi junction solar cell, in particular a concentrator solar cell, wherein the solar cell structures with several subcells are deposited onto a substrate, such as a Ge or GaAs substrate, wherein an active solar cell area is defined as a solar cell structure by an etching, laser, or sawing process with subsequent overetching under formation of a circumferential surface and wherein the substrate is severed by sawing or lasing under formation of peripheral lateral faces into substrate sections for forming the individual multi junction solar cells.

#Multi-junction solar cells are principally used in space travel and in terrestrial concentrator photovoltaic systems, CPV, which are increasingly gaining importance on the market for photovoltaics. Extended trouble-free service life is a pre-requirement for the cost-effectiveness of these systems and to gain further recognition. But on the other hand this will require overcoming a combination made up of widely varying environmental influences, such as moisture, temperature fluctuations, and UV light, which have a negative effect with respect to the reliability of individual components, submodules, and modules.

#Further particulars, advantages and features of the invention result not only from the Claims, and the features to be found in them, either individually and/or in combination, but also from the following description and from the preferred embodiments to be found in the drawing, as follows:

#FIG. 1 is a schematic representation of an encapsulated solar cell according to prior art,

#FIG. 3 shows a structure of a conventional CPV multi-junction solar cell.

#FIG. 3 shows a structure of a conventional CPV multi-junction solar cell 10, comprising a substrate 12, such as a Ge or GaAs substrate, with a solar cell structure 14 deposited onto it, wherein a lowest cell of the multi junction solar cell can form directly in the substrate 12 during a deposition process.

#During the production of CPV multi-junction solar cells 10, semi conductor layers are normally applied epitaxially onto a wafer forming the substrate. The wafer and/or substrate material normally involves a Ge or GeAs material. The deposited layers form subcells, wherein according to FIG. 3, this can include the solar cell structure of the subcells 14 a, 14b, 14c. After the deposition of semiconductor materials, application of a front-side contact 18, particularly in form of a metallic lattice, as well as an anti-reflex coating 20 and a rear-side metallization 22 on the back of the substrate, if necessary, using etching, laser or sawing processes with subsequent overetching, active solar cell areas are produced which have a mesa structure with a circumferential surface 16. The substrate is then severed particularly by sawing into individual substrate sections 12, each of which have a peripheral side face 14.

#As can be seen from the diagrammatic representation of FIG. 3, the active area, i.e. the solar cell structure 14 with the circumferential surface 16 runs spaced apart from the peripheral side face 24 of the substrate section 12, which hereinafter is simply termed substrate.