Free-standing metallic article for semiconductors
View Patent ↗A free-standing metallic article, and method of making, is disclosed in which the metallic article is electroformed on an electrically conductive mandrel. The mandrel has an outer surface with a preformed pattern, wherein at least a portion of the metallic article is formed in the preformed pattern. The metallic article is separated from the electrically conductive mandrel, which forms a free-standing metallic article that may be coupled with the surface of a semiconductor material for a photovoltaic cell.
1. A method of forming an electrical component for a photovoltaic cell, the method comprising the steps of:
i) electroforming a metallic article on an electrically conductive mandrel, wherein the electrically conductive mandrel has an outer surface comprising at least one preformed pattern, the preformed pattern comprising a continuous grid pattern coupled to a cell interconnection pattern,
wherein the metallic article comprises a plurality of electroformed elements formed in the preformed pattern, the plurality of electroformed elements comprising a cell interconnection element coupled to a continuous grid having a plurality of first elements intersecting a plurality of second elements, and wherein the cell interconnection element is configured to directly couple the grid to a neighboring cell; and
ii) separating the metallic article from the electrically conductive mandrel, wherein the plurality of electroformed elements are interconnected such that the metallic article forms a unitary, free-standing piece when separated from the electrically conductive mandrel;
wherein the preformed pattern has a height and a width, wherein the ratio of the height to the width is an aspect ratio, and wherein the preformed pattern has an aspect ratio greater than 1; and
wherein the plurality of electroformed elements are configured to serve as an electrical conduit for a light-incident surface of a photovoltaic cell.
2. The method of claim 1 , wherein the aspect ratio is between about 1 and about 10.
3. The method of claim 1 , wherein the step of electroforming comprises overplating the electroformed elements such that the electroformed elements extend above the outer surface of the electrically conductive mandrel.
4. The method of claim 1 , wherein the step of electroforming the metallic article comprises contacting the outer surface of the mandrel with a first solution comprising a salt of a first metal, wherein a first metallic layer comprising the first metal is formed within the preformed pattern.
5. The method of claim 1 , wherein the plurality of first elements and the plurality of second elements comprise a plurality of substantially parallel first elements intersecting a plurality of substantially parallel second elements, wherein the plurality of first elements and the plurality of second elements are coplanar such that one of the first elements has a first cross-section that overlaps a majority of a second cross-section of one of the second elements.
6. The method of claim 5 , wherein each of the plurality of first elements has a width of between about 10 microns and about 5000 microns and each of the plurality of second elements has a width of between about 10 microns and about 5000 microns.
7. The method of claim 5 , wherein the plurality of substantially parallel first elements and the plurality of substantially parallel second elements are linear and intersect perpendicularly.
8. The method of claim 1 , wherein the preformed pattern has a tapered cross sectional shape, being wider at the outer surface of the electrically conductive mandrel.
9. The method of claim 1 , wherein the electrically conductive mandrel has a first outer surface and a second outer surface opposite the first outer surface, wherein the first outer surface comprises a first preformed pattern and the second outer surface comprises a second preformed pattern.
10. The method of claim 9 , wherein the first preformed pattern and the second preformed pattern are different from each other.
11. The method of claim 1 , wherein the electrically conductive mandrel is metallic, and wherein the at least one preformed pattern comprises at least one pattern element as a cavity in the electrically conductive mandrel.
12. The method of claim 11 , wherein the pattern element is an intersecting trench having three metal sides.
13. The method of claim 11 , wherein the electrically conductive mandrel comprises a first layer on the outer surface, and wherein the first layer comprises at least one of a low-adhesion material or a dielectric material.
14. The method of claim 13 , wherein the first layer extends at least partially into the pattern element.
15. A method of forming an electrical component for a photovoltaic cell, the method comprising the steps of:
i) electroforming a metallic article on an electrically conductive mandrel, wherein the electrically conductive mandrel has an outer surface comprising at least one preformed pattern, the preformed pattern comprising a continuous grid pattern coupled to a cell interconnection pattern,
wherein the metallic article comprises a plurality of electroformed elements formed in the preformed pattern, the plurality of electroformed elements comprising a cell interconnection element coupled to a continuous grid having a plurality of first elements intersecting a plurality of second elements, and wherein the cell interconnection element is configured to directly couple the grid to a neighboring cell; and
ii) separating the metallic article from the electrically conductive mandrel, wherein the plurality of electroformed elements are interconnected such that the metallic article forms a unitary, free-standing piece when separated from the electrically conductive mandrel;
wherein the preformed pattern has a height and a width, wherein the ratio of the height to the width is an aspect ratio, and wherein the preformed pattern has an aspect ratio greater than 0.1; and
wherein the plurality of electroformed elements are configured to serve as an electrical conduit for a light-incident surface of a photovoltaic cell.
16. The method of claim 15 , wherein the step of electroforming comprises overplating the electroformed elements such that the electroformed elements extend above the outer surface of the electrically conductive mandrel.
17. The method of claim 16 , wherein the overplating forms a rounded top.
18. The method of claim 16 , wherein a top surface of the overplating provides an optical surface that aids in light collection for the photovoltaic cell.
19. The method of claim 15 , wherein the preformed pattern has a tapered cross sectional shape, being wider at the outer surface of the electrically conductive mandrel.
20. The method of claim 19 , wherein the step of electroforming comprises overplating the electroformed elements such that the electroformed elements extend above the outer surface of the electrically conductive mandrel.
21. The method of claim 15 , wherein the cell interconnection element comprises a bus bar.
22. The method of claim 21 , wherein the cell interconnection element has a height that is less than the height of the continuous grid.
23. The method of claim 15 , wherein the aspect ratio is between about 0.1 and about 1.