TWI612685B - Adaptable free-standing metallic article for semiconductors - Google Patents

Abstract

A self-standing metal object and method of manufacture are disclosed, wherein the metal object is electroformed on a conductive mandrel. The metal article has a plurality of electroformed components configured to function as an electrical conduit for a photovoltaic cell. A first electroformed component has at least one of: a) a non-uniform width along one of the first lengths of the first component, b) a change in direction of the conduit along the first length of the first component, c) An expansion section of the first length of the first member, d) a first width different from a second width of one of the plurality of electroformed components, e) and a plurality of electroformed components One of the second elements has a second height that differs from the first height, and f) one of the textured top surfaces.

Description

Adaptable self-standing metal objects for semiconductors Cross-reference to related applications

The present application claims priority to U.S. Patent Application Serial No. 14/079,540, the entire disclosure of which is incorporated herein by reference in its entirety in its entirety in its entirety in </ RTI> <RTIgt; </ RTI> <RTIgt; </ RTI> <RTIgt; </ RTI> <RTIgt; </ RTI> <RTIgt; </ RTI> <RTIgt; </ RTI> <RTIgt; This article. The present application is also related to U.S. Patent Application Serial No. 14/079,544, the entire disclosure of which is incorporated herein by The possessor owns and incorporates this article by reference.

This invention relates to an adaptable self-standing metal article for a semiconductor.

Background of the invention

A solar cell is a device that converts photons into electrical energy. The electrical energy generated by the battery is collected via electrical contacts coupled to the semiconductor material and arranged The route is interconnected with other photovoltaic cells in the module. The "standard battery" model of solar cells has a semiconductor material that absorbs incident solar energy and converts it into electrical energy, placed beneath the anti-reflective coating (ARC) layer and above the metal backplane. Electrical contact to the surface of the semiconductor is typically made by firing through the paste which is heated to diffuse the paste through the ARC layer and to contact the metal paste on the surface of the cell. The paste is substantially patterned into a set of fingers and bus bars, which are then lead welded to other cells using a tape to create a module. Another type of solar cell has a semiconductor material sandwiched between transparent conductive oxide layers (TCO), which is then coated with a final conductive paste layer, which is also configured in accordance with the finger/bus bar pattern.

Among the two types of batteries, silver metal paste is generally used to support electricity. The flow flows in a horizontal direction (parallel to the surface of the cell), which in turn allows the fabrication of connections between the solar cells to create a module. Solar cell metallization is most commonly achieved by printing a silver paste screen onto a cell, curing the paste, and subsequently lead welding across the screen printing bus bar. However, silver is expensive relative to other components of solar cells and accounts for a high percentage of the total cost.

To reduce silver costs, the art is known for metallizing solar power An alternative to the pool. For example, attempts have been made to replace copper with copper by electroplating copper directly onto a solar cell. However, the disadvantage of copper plating is that the battery is contaminated with copper, which affects reliability. When directly electroplating to the surface of the cell, the amount of plating production and yield can also be problematic due to the numerous steps required for electroplating, such as depositing a seed layer, applying a mask, and etching or laser-etching the plated area to form the desired pattern. Other methods for forming an electrical conduit on a solar cell include encapsulating the conductive lines with parallel lines or polymeric sheets and laying them up to electricity On the pool.

Summary of invention

A self-standing metal object and method of manufacture are disclosed, wherein the metal object is electroformed on a conductive mandrel. The metal article has a plurality of electroformed components configured to be used as an electrical conduit for a photovoltaic cell. The first electroformed component has at least one of: a) a non-uniform width along a first length of the first component, b) a change in direction of the conduit along a first length of the first component, and c) a first along the first component a lengthwise expansion section, d) a first width different from a second width of the second of the plurality of electroformed components, e) a first difference from a second height of the second of the plurality of electroformed components Height, and f) textured top surface.

100, 102‧‧‧ mandrel

105‧‧‧Outer surface

110, 112, 115‧‧‧ pattern elements

150, 152, 154‧‧‧ electroforming components

160‧‧‧ Nickel layer

180, 350, 355, 400, 800, 1100, 1210, 1260‧‧‧ metal objects

190, 830, 840‧‧‧ intersecting components

300a, 300b‧‧‧ metal layer

310‧‧‧Parallel fingers/vertical fingers

310, 320‧‧‧ fingers (components)

312, 322‧‧‧ bottom surface

320‧‧‧ horizontal fingers

330‧‧‧Frame components

360, 430, 440, 600, 610, 1220‧‧‧ interconnection components

370‧‧‧First (square) area

380‧‧‧Second District

390‧‧‧catheter/square/second area

402‧‧‧Semiconductor substrate

410, 420, 810, 820, 900, 1110, 1120‧‧‧ grid lines

412, 422, 432, 442, 602, 622, 812a, 812b, 908, 912, 1112, 1122‧‧ Width

414‧‧‧ Height

450, 455, 1130‧‧‧ edge members

605‧‧‧ front edge

606, 624‧‧‧ length

620‧‧‧ pores

650a, 650b‧‧‧ substrate

651, 652, 1360‧‧ ‧ gap

710, 720‧‧‧ electroforming components

715, 725‧‧‧ top surface

720‧‧‧Overplating components

722‧‧‧ coating

910‧‧‧ nominal width

940‧‧‧Interconnected area

1010a/b/c/d/e, 1270‧‧ ‧ bus bars

1011c, 1021c‧‧ cycle

1011d‧‧‧Arc section

1011e, 1021e‧‧‧ curved part

1012c, 1022c‧‧‧ amplitude

1013d/e, 1023e‧‧‧ straight section

1020a/b/c/d/e‧‧‧ cross-members

1030a/b/c/d/e‧‧‧ intersection

1040a/b/c/d/e, 1150‧‧‧ solder pads

1050b‧‧‧bonding area

1140‧‧‧ Corner members

1160‧‧‧radial pillar

1200, 1250, 1310, 1320, 1330, 1340‧‧‧ batteries

1300‧‧‧Module

1350‧‧‧ positive terminal

1355‧‧‧Negative terminal

1400‧‧‧flow chart

1410-1450‧‧‧Steps

The various aspects and embodiments of the invention described herein can be used alone or in combination with one another. The aspects and embodiments will now be described with reference to the drawings.

Figure 1 shows a perspective view of an exemplary electroformed mandrel in an embodiment.

2A through 2C depict cross-sectional views of an exemplary stage in the manufacture of a self-standing electroformed metal article.

3A to 3B are top views of two embodiments of metal objects.

Figure 3C is a cross-sectional view of section A-A of Figure 3B.

3D through 3E are partial cross-sectional views of other embodiments of the cross section of Fig. 3B.

3F to 3G are embodiments of metal objects having interconnecting elements Top view.

Figure 4 provides a top view of a metal article having an adaptable feature in an embodiment.

Figure 5 is an exemplary partial cross section of section C of Figure 4.

Figure 6 is a detailed top plan view of the interconnected regions in an embodiment.

Figures 7A through 7B are vertical cross-sections of section D of Figure 4 in certain embodiments.

Figure 8 shows a top view of a metal article having an adaptable feature embodiment for the front side of a photovoltaic cell.

Figure 9 is a detailed top view of an exemplary grid line having a tapered width along its length.

10A through 10E are simplified schematic views of various embodiments of the expansion section.

Figure 11 shows a top view of a metal article having an adaptable feature embodiment for the back side of a photovoltaic cell.

Figure 12 illustrates an inter-cell interconnection between an exemplary front mesh and a rear mesh.

Figure 13 shows an exemplary photovoltaic cell that forms a module assembly from a metal object.

14 is a flow diagram of an exemplary method of forming a photovoltaic module using the metal article of the present invention.

Detailed description of the preferred embodiment

The metallization of solar cells is custom printed on screens. The silver paste on the surface of the battery and the inter-battery interconnection using the solder coated tape are achieved. In terms of the specified metal conduit aspect ratio, the resistance is inversely proportional to its footprint. Therefore, battery metallization or inter-cell interconnect design typically trades between shadow and resistance to achieve an optimized solar cell module power output. The metal articles of the present invention, also referred to as squares or grids, can be used in place of conventional silver pastes and solder coated tapes and have adaptable features that allow for decoupling factors that are customarily required to be traded between functional requirements.

U.S. Patent Application Serial No. 13/798,123 to Babayan et al. In the number, an electric conduit of a semiconductor (such as a photovoltaic cell) is fabricated into an electroformed self-standing metal object. Metal objects are manufactured separately from solar cells and include a plurality of components, such as fingers and bus bars, that can be stably transferred as a single piece of workpiece and easily aligned with a semiconductor device. In the electroforming process, the components of the metal object are integrally formed with each other. Metal objects are fabricated in an electroformed mandrel that produces a patterned metal layer that is customized for solar cells or other semiconductor devices. For example, a metal object can have a checkered line that has a high to wide aspect ratio that minimizes the shadow of the solar cell. Metal objects can replace the conventional bus bar metallization and tape routing for battery metallization, inter-cell interconnection, and module fabrication. The ability to create a metallization layer of photovoltaic cells that creates a separate component that can be stably transferred between processing steps provides various advantages in material cost and manufacturing.

Figure 1 depicts one of the US patent applications No. 13/798,123 A perspective view of a portion of an exemplary electroformed mandrel 100 in an embodiment. The mandrel 100 can be made of a conductive material such as stainless steel, copper, anodized aluminum, titanium or molybdenum, nickel, nickel-iron alloy (eg, Invar), copper, or any of these metals. Combined, and designed to have sufficient area to allow for high plating currents and support high throughput. The mandrel 100 has an outer surface 105 having a preformed pattern that includes pattern elements 110 and 112 and that can be customized for the desired shape of the electrical conduit element that is intended to be fabricated. In this embodiment, pattern elements 110 and 112 are grooves or grooves having a rectangular cross-section, although in other embodiments pattern elements 110 and 112 may have other cross-sectional shapes. The pattern elements 110 and 112 are depicted as forming intersecting sections of a checkered pattern, wherein in this embodiment, the sets of parallel lines intersect each other perpendicularly.

The pattern element 110 has a height "H" and a width "W", wherein The high aspect ratio is defined as the aspect ratio. By using pattern elements 110 and 112 for mandrel 100 to form a metal object, custom electroformed metal parts can be applied for photovoltaic applications. For example, the aspect ratio can be between about 0.01 and about 10 as needed to meet the shadow limitations of solar cells.

Aspect ratio of the pattern elements as well as cross-sectional shape and longitudinal layout Can be designed to meet required specifications such as current capacity, series resistance, shadow loss, and battery layout. Any electroforming process can be used. For example, a metal object can be formed by an electroplating process. In particular, since the electroplating is essentially an isotropic process, the use of a pattern mandrel limits the importance of electroplating to the shape of the customized part to maximize efficiency. Moreover, while certain cross-sectional shapes may be unstable when placed on a semiconductor surface, customized patterns that can be made through the use of a mandrel allow features such as interconnect lines to provide stability to such conduits. In some embodiments, for example, the preformed pattern can be configured to have a continuous grid of intersecting lines. This configuration not only provides mechanical stability to the plurality of electroformed components forming the grid, but also because the current is distributed more The conduit provides a low series resistance. The square structure also improves the robustness of the battery. For example, if some parts of the square are damaged or not working, the current may flow around the damaged area due to the presence of the checkered pattern.

Figures 2A through 2C are, for example, U.S. Patent Application Serial No. 13/798,123 A simplified cross-sectional view of an exemplary stage disclosed in the fabrication of a metal layer workpiece using a mandrel. In FIG. 2A, a mandrel 102 having pattern elements 110 and 115 is provided. The pattern element 115 has a tapered vertical cross section with the outer surface 105 of the mandrel 102 widened. The tapered vertical cross section may provide certain functional benefits, such as increasing the amount of metal to improve electrical conductivity, or assisting in the removal of the electroformed workpiece from the mandrel 102. The mandrel 102 should be subjected to an electroforming process in which exemplary electroformed components 150, 152, and 154 are formed in pattern elements 110 and 115, as shown in FIG. 2B. Electroformed components 150, 152, and 154 can be, for example, pure copper or copper alloys. In other embodiments, the nickel layer may first be electroplated onto the mandrel 102, followed by electroplating of copper, such that the nickel provides a barrier that prevents the final semiconductor device from being contaminated with copper. Another nickel layer may optionally be electroplated on top of the electroformed component to encapsulate the copper, as depicted by the nickel layer 160 on the electroformed component 150 in Figure 2B. In other embodiments, multiple layers may be used to plate multiple layers into pattern elements 110 and 115 as needed to achieve the desired properties of the metal article to be fabricated.

In Figure 2B, electroformed components 150 and 154 are shown as forming and The outer surface 105 of the mandrel 102 is flush. Electroformed component 152 illustrates another embodiment of an overplatable component. In the case of electroformed component 152, the electroplating continues until the metal extends over surface 105 of mandrel 102. The overplated portion that forms the rounded top due to the isotropic nature of the electroforming is typically used as a handle to facilitate extraction of the electroformed component 152 from the mandrel 102. The rounded top of electroformed component 152 can also be used in photovoltaics Optical advantages are provided in the battery, for example, as a refractive surface to aid in light collection. In other embodiments not shown, the metal article may have portions formed on top of the mandrel surface 105, such as bus bars, in addition to those formed in the preformed patterns 110 and 115.

In Figure 2C, electroformed components 150, 152, and 154 are self-mandrel 102. The self-standing metal object 180 is removed. Note that Figures 2A through 2C show three different types of electroformed components 150, 152, and 154. In various embodiments, the electroformed components within the mandrel 102 can all be of the same type, or can have different combinations of electroformed patterns. Metal object 180 can include intersecting elements 190 as may be formed by cross member pattern 112 of FIG. The intersecting elements 190 can assist in forming the metal article 180 into a single piece of self-standing workpiece so that it can be easily transferred to other processing steps while maintaining the individual elements 150, 152, and 154 aligned with each other. Other processing steps may include a coating step from the standing metal object 180 and an assembly step of incorporating it into the semiconductor device. By making the metal layer of the semiconductor self-standing workpiece, the manufacturing yield of the entire semiconductor assembly will not be affected by the yield of the metal layer. In addition, the metal layer can be separated from other semiconductor layers by temperature and process. For example, the metal layer can undergo a high temperature process or chemical bath that will not affect the remainder of the semiconductor assembly.

After the metal object 180 is removed from the mandrel 102 in Figure 2C, The mandrel 102 can be reused to make other parts. Since the mandrel 102 can be reused, it provides a significant cost reduction over the prior art that directly performs electroplating on solar cells. In the direct plating method, the mask or mandrel is formed on the battery itself, and thus must be built on each battery and often broken. Compared to the technology that requires patterning and subsequent plating of semiconductor devices, The mandrel is then used to reduce processing steps and save money. In other conventional methods, a thin printed seed layer is applied to the surface of the semiconductor to begin the electroplating process. However, the seed layer results in low throughput. In contrast, a reusable mandrel as described herein can utilize a thick metal mandrel that allows for high current capacity, thereby resulting in high plating currents and thus high throughput. The metal mandrel thickness can be, for example, between 0.2 and 5 mm.

3A and 3B illustrate an electroformed mandrel that can be fabricated by the methods described herein A top view of exemplary metal layers 300a and 300b is fabricated. Metal layers 300a and 300b include electroformed elements embodied herein as substantially parallel fingers 310 that have been formed by substantially parallel grooves in the conductive mandrel. Metal layer 300b also includes an electroformed component embodied herein as horizontal fingers 320 that intersects vertical fingers 310, wherein fingers 310 and 320 intersect at approximately right angles. In other embodiments, the fingers 310 and 320 may intersect at other angles while still forming a continuous grid or grid pattern. The metal layers 300a and 300b also include a frame member 330 that can be used as a bus bar to collect current from the fingers 310 and 320. Integrating the bus bars formed as part of a metal object provides a manufacturing improvement. In the high-capacity solar module manufacturing method, the battery connection is often achieved by artificially soldering the metal strip to the battery. This practice often results in battery breakage or damage due to manual handling and stress imposed on the battery by the lead strip. In addition, manual lead welding methods result in high labor-related production costs. Thus, as is possible with the electroformed metal articles described herein, bus bars or strips previously formed and attached to the metallization layer support low cost automated manufacturing methods.

Frame member 330 can also provide mechanical stability to enable self-centering When the shaft is removed, the metal layers 300a and 300b are self-standing workpieces in a single piece. That is, the metal layers 300a and 300b are single pieces because the fingers 310 and 320 remain connected when they are a single component from the photovoltaic cell or other semiconductor components. Frame element 330 may additionally assist in maintaining the spacing and alignment between finger elements 310 and 320 when it is contemplated to attach the finger elements to the photovoltaic cells. Frame member 330 is shown extending across one of the edges of metal layers 300a and 300b in Figures 3A-3B. However, in other embodiments, the frame member may extend only partially across one edge, or may be bordered by more than one edge, or may be configured as one or more ears on the edge, or may reside on the square itself Inside. Additionally, frame member 330 can be electroformed simultaneously with fingers 310 and 320, or in other embodiments can be electroformed in separate steps after fingers 310 and 320 have been formed.

Figure 3C shows the metal layer taken at section A-A of Figure 3B. Cross section of 300b. In this embodiment, the fingers 310 are shown to have an aspect ratio greater than 1, such as from about 1 to about 5, and in this figure, such as about two. The wider cross-sectional height reduces the shadowing effect of the metal layer 300b on the photovoltaic cell. In various embodiments, only a portion of the fingers 310 and 320 can have an aspect ratio greater than one, or more than half of the fingers 310 and 320 can have an aspect ratio greater than one. In other embodiments, some or all of the fingers 310 and 320 can have an aspect ratio of less than one. The height "H" of the fingers 310 can range, for example, from about 5 microns to about 200 microns, or from about 10 microns to about 300 microns. The width "W" of the fingers 310 can range, for example, from about 10 microns to about 5 mm, such as from about 10 microns to about 150 microns. The distance between the parallel fingers 310 has a distance "P" measured between the lines of the fingers. In some real In an embodiment, the spacing can be between, for example, between about 1 mm and about 25 mm. In Figures 3B and 3C, the fingers 310 and 320 have different widths and spacings, but the heights are substantially equal. In other embodiments, the fingers 310 and 320 can have different widths, heights, and spacings from one another, or can have some of the same characteristics, or can have all of the same characteristics. The value is chosen based on a number of factors, such as the size of the photovoltaic cell, the amount of shadow required, or the coupling of metal objects to the front or rear of the cell. In some embodiments, the fingers 310 can have a spacing of between about 1.5 mm and about 6 mm, and the fingers 320 can have a spacing of between about 1.5 mm and about 25 mm. Fingers 310 and 320 are formed in a mandrel having a shape and spacing substantially the same as the grooves of fingers 310 and 320. The frame member 330 can have the same height as the fingers 310 and 320, or can be a thinner workpiece as indicated by the dashed lines in Figure 3C. In other embodiments, frame member 330 can be formed over finger members 310 and 320.

FIG. 3C also shows that the fingers 310 and 320 can be substantially shared with each other. The faces are due to the fact that the fingers 310 and 320 have more than half of their cross-sectional areas that overlap each other. Coplanar squares as depicted in Figure 3C can provide a lower profile with overlapping circular lines of the same cross-sectional area than conventional meshes that are woven up and down. The intersecting coplanar lines of the metal layer 300b are also integrated with each other during the electroforming process, thereby providing greater robustness to the self-standing articles of the metal layer 300b. That is, the integrating elements are formed as a workpiece rather than being joined together by separate components. Figures 3D and 3E show other embodiments of coplanar intersecting elements. In FIG. 3D, the fingers 310 are shorter in height than the fingers 320 but are positioned within the cross-sectional height of the fingers 320. Fingers 310 and 320 each have bottom surfaces 312 and 322 that are aligned in this embodiment, such as to provide for mounting to a semiconductor meter The flat surface used for the surface. In the embodiment of FIG. 3E, the fingers 310 have a greater height than the fingers 320 and extend beyond the top surface of the fingers 320. More than half of the cross-sectional area of the fingers 310 overlaps the entire cross-section of the fingers 320, and thus the fingers 310 and 320 are coplanar as defined herein.

Figures 3F and 3G show other embodiments in which an electroformed metal object Supports the interconnection between photovoltaic cells in the module. Common modules have many batteries connected in series, such as between 36 and 60. The connections are made by attaching the front of a battery to the back of the next cell using a solder coated copper strip. Attaching the strap in this manner requires a thin strap so that the strap can bend around the battery without damaging the battery edge. Since the belt is very narrow, the use of a thin strip increases the resistance. Interconnects typically also require three separate strips for separate lead soldering. In the embodiment of FIG. 3F, metal object 350 has interconnecting elements 360 that have been electroformed with first checker zone 370. Interconnect element 360 has a first end coupled to square 370 and is configured to extend beyond the surface of the photovoltaic cell to allow connection to an adjacent cell. Interconnect element 360 replaces the need to lead the separation tape between cells, thereby reducing manufacturing costs and supporting feasible automation. In the embodiment shown, interconnect element 360 is a straight section, although other configurations are possible. Moreover, the number of interconnect elements 360 can be varied as desired, such as providing multiple elements 360 to reduce electrical resistance. The interconnecting elements 360 can be bent or angled after electroforming, for example to support front to back connections between the cells, or can be made in the mandrel to be angled relative to the grid 370.

The opposite ends of the interconnecting member 360 can be coupled to the second region 380, The second intermediate zone 380 can also be electroformed as part of the metal object 350 in the conductive mandrel. In FIG. 3F, the second zone 380 is configured as a tab (eg, a bus bar), It can then be electrically connected to an electrical conduit 390 of an adjacent battery. The conduit 390 is here configured as an array of components, but other configurations are possible. The grid 370 can be used, for example, as an electrical conduit on the front surface of the first battery, and the square 390 can be an electrical conduit on the surface behind the second battery. In the embodiment of Figure 3G, the metal object 355 has a mesh instead of a bus bar type connection. The metal article 355 includes a first region 370, an interconnecting member 360, and a second region 390, all of which have been electroformed into a single component such that the inter-cell connection has been provided by the metal article 355. Thus, metal objects 350 and 355 not only provide electrical conduits on the surface of a photovoltaic cell, but also provide interconnection between the cells.

Metal objects made by electroforming mandrels have even advanced The steps are tailored to meet the required functions and manufacturing requirements of a particular photovoltaic cell. For example, the individual shapes of the components within the metal article can be customized, or the components in one of the regions of the metal article can be designed to have features that are geometrically different from the components in another region. The customized features described herein can be used alone or in combination with each other. The use of an electroformed mandrel decouples the size constraints of the entire electroformed workpiece so that the features can be optimized for specific areas within the metal object. In addition, metal objects manufactured by the method support customization for specific types of batteries, such as from low cost consumer batteries to high efficiency batteries. The features of the metal object also allow the interconnection components to be integrated so that the solar cells using the metal object as an electrical conduit are ready for use as a module. The metallization provided by the metal articles described herein provides a higher metallization volume and lower resistance than conventional battery metallization with the same footprint, while reducing cost compared to silver-based and ribbon-based metallization. These metal objects also promote the design of photovoltaic cells with light and voltage sag tolerance.

Figure 4 shows the implementation of various features of a photovoltaic cell A top view of a metal object 400 of an example. The semiconductor substrate 402 is shown in dashed lines to show the placement of the metal object on the photovoltaic cell, where the metal object 400 is configured here as a square for the front side of the cell. However, the features described herein can be applied to an electrical conduit on the back side of a photovoltaic cell. In the present invention, references to the formation of semiconductor materials in semiconductor devices or photovoltaic cells may include non-transformed germanium, crystalline germanium or any other semiconductor material suitable for use in photovoltaic cells. The metal objects can also be applied to other types of semiconductor devices other than photovoltaic cells. The semiconductor substrate 402 is shown in FIG. 4 as a single crystal cell having a rounded corner (also referred to as a quasi-square). In other embodiments, the semiconductor substrate can be a polymorph having a full square shape. The semiconductor substrate 402 can have an electrical conduit wire (not shown), such as a silver finger, on its surface that carries the current generated by the substrate 402. The silver fingers can be screen printed onto the semiconductor substrate 402 in accordance with conventional methods. For example, the silver fingers can be perpendicular to the direction of the checkered line 410. The components of the metal article 400 are then used as electrical conduits to carry current from the silver fingers. In the embodiment of FIG. 4, the square lines 410 (in the horizontal of FIG. 4) and 420 (the vertical in FIG. 4) of the metal object 400 are electrically coupled to the semiconductor 402, such as through lead soldering, to collect Current is delivered to interconnect elements 430 and 440. As described in Figures 3F through 3G, the interconnecting elements provide an inter-cell connection of the solar modules. Compared to batteries that use silver for electrical conduits, the fabrication of metal articles 400 from metals such as copper reduces cost and can also improve battery efficiency due to improved electrical conductivity.

The ruled lines 410 and 420 of Figure 4 are shown as being substantially perpendicular to each other; however, in other embodiments, they may be at an angle that is not perpendicular to each other. Although the party Both the grid line 410 and the intersecting grid line 420 can carry current, but the grid line 410 provides a minimum resistance path to the interconnecting elements 430 and 440 and can serve as the primary carrier for the current. Thus, the checkered line 410 should also be referred to as a bus bar, and the intersecting checkered line 420 can be referred to as a cross member. The cross member 420 provides mechanical support for the self-standing metal object 400 in terms of strength and maintaining the dimensions of the square. However, the cross member 420 can also function as an electrical conduit, such as if the bus bar 410 fails. In some embodiments, the checkered lines 410 and 420 can have different widths 412 and 422 from each other, such as to optimize mechanical strength or achieve a desired fill factor for the battery. For example, the width 412 of the checker line 410 may be smaller than the width 422 of the checker line 420 such that the checkered line 420 provides sufficient mechanical stability of the metal object 400 while the checker line 410 is customized to achieve the highest possible Fill factor. In other embodiments, some of the checkered lines 410 may have a different width than the other checkered lines 410, such as to address the mechanical strength or capacitance of a particular zone. The spacing between bus bars 410 may also vary relative to cross member 420, or may differ from one another in different regions within metal object 400 to meet the desired device conduction requirements. In some embodiments, a coarser or finer grid spacing may be selected based on, for example, the silver finger design of the wafer, the accuracy of the silver screen printing process, or the type of battery used.

The checkered lines 410 and 420 also include edge members 450 and 455, etc. It is configured to be located near the perimeter of the solar cell. For example, edge members 450 and 455 can be located 1 to 3 mm from the edge of wafer 402. Because the edge members 450 and 455 form the perimeter of the metal object 400, the edge members 450 and 455 can be wider than the other grid lines 410 and 420 inside the metal object 400 to provide additional structural support. In the embodiment of Figure 4, the edge member 455 is configured as an autonomous edge Member 450 forms a corner bus bar of a certain angle. That is, the edge member 450 has a change in the direction of the conduit of the length, such as to accommodate the quasi-square shape in this embodiment. This change in direction can be formed by integration of the electroformed mandrel and can include the width of the custom corner bus bar 455 to improve mechanical strength and reduce resistive losses. When the metal object 400 is attached to the semiconductor substrate 402, the wider bus bars 450 and 455 at the perimeter of the metal object 400 can also improve the bond strength.

Interconnecting elements 430 and 440 are near the edge of metal object 400, It may also have a different width 432 and 442 than other areas of the metal object 400. For example, interconnect element 430 can have a width 432 that is greater than the width 412 of the checker line 410. Thus, the width 432 is decoupled from the width limit of the face of the battery and allows for lower resistance without affecting the effective area of the battery. Since the electroforming process is isotropic, the increased width 432 can result in a thinner interconnect element 430. Figure 5 shows a vertical cross section of section C of Figure 4, thereby showing an exemplary height difference between elements 410 and 430. In FIG. 5, the checkered line 410 has a height 414 that is greater than the height 434 of the interconnecting member 430. That is, the square line 410 at the edge of the wafer is narrower and taller than the wider and thinner interconnect 430. The thinner interconnect 430 can improve resistance to fatigue failure such as deflection during transport and exposure to environmental forces while minimizing voltage loss by providing a large surface area for current flow. For example, in some embodiments, the thickness or height 434 of the interconnect 430 can be 40 to 120 [mu]m, such as 50 to 70 [mu]m, and the checkered line 410 can have a thickness or height 414 of 100 to 200 [mu]m, such as 100 to 150 [mu]m.

6 shows an exemplary interconnection similar to interconnect element 440 of FIG. A detailed top view of component 600. Interconnect element 600 acts as a pad for the back of an adjacent cell while interconnect element 610 acts as an electrical conduit between the solar cells. Note that the plate type design of the interconnect 600 has a large surface area compared to conventional solder tapes, such as 5 times or 10 times that of conventional batteries using three bus bars. Therefore, the design of interconnect 600 improves efficiency at the module level by providing low series resistance and minimal voltage drop. For example, the width 602 of the interconnecting member 600 can be 5 to 10 mm, such as 6 to 8 mm, as compared to the width of 50 to 100 μm of the checkered lines 410 and 420 of FIG. The length 606 of the interconnecting member 600 can be close to the edge length of the photovoltaic cell, such as the entire edge of the polycrystalline cell or the length between the corners of the single crystal cell. Interconnect element 600 can also be used as a manufacturing aid to remove metal objects (e.g., metal object 400 of Figure 4) from an electroformed mandrel. The interconnect element 610 can be bent or angled after electroforming, such as to support a front-to-back connection between the cells. Interconnect elements 600 and 610 can be formed integrally with grid lines 410 and 420, which can reduce manufacturing costs by eliminating bonding steps. In other embodiments, interconnecting elements 600 and/or 610 can be formed to separate the workpiece and subsequently bonded to the checkered lines 410 and 420, such as to allow interchangeable interconnecting elements having different square designs.

Interconnect elements 600 and 610 can have the remainder with metal object 400 Partially different heights, i.e., thickness, are similar to the height difference between the ruled line 410 and the interconnecting element 430 shown in FIG. In some embodiments, for example, interconnect element 610 can have a height of 50 to 70 μm and interconnect element 60 can have a height of 40 to 100 μm. Because interconnect element 610 provides mechanical and electrical connections between the cells in the module, component 610 can be customized to have a specific thickness to meet specified flexural testing requirements. The number of components 610 can also be increased compared to conventional single-belt accessories for improved reliability and flexural test endurance. The increased number of interconnecting elements 610 also provides a larger electrical conduit area, and thus a smaller electrical resistance. In some embodiments, it has been found that there are 15 to 30 with The metal object of the interconnecting member 610 having a height of 50 to 70 μm can withstand a flexural failure cycle of ten to one hundred times more than a conventional copper solder tape having a thickness of 150 μm.

Figure 6 shows other features of the presence of aperture 620 of interconnect element 600. unit. The aperture 620 extends through the opening of the thickness of the interconnecting member 600 in the form of a circular, elliptical or other shaped aperture or slit. These apertures 620 allow for the release of trapped air during lamination of the photovoltaic cell assembly, thereby promoting void-free encapsulation. The dashed lines 650a and 650b represent the placement of the semiconductor substrate in an embodiment wherein the substrate 650a represents the attachment on the front side of the photovoltaic cell and the substrate 650b is the attachment on the back side of the adjacent cell. The substrate 650a can be positioned, for example, with a gap 651 of 0.5 to 1.5 mm from the front edge 605 of the interconnect element 600, while the substrate 650b can be positioned, for example, with a gap 652 of 1.5 to 2.5 mm from the edge 605. As can be seen in Figure 6, at least a portion of the apertures 620 remain exposed between the cells for mechanical strength purposes, thereby permitting the module laminate, such as ethylene vinyl acetate (EVA), to penetrate the interconnecting member 600. The apertures 620 also provide a means for any air bubbles within the laminate to escape. The number and size of the apertures 620 can be selected to promote the lamination process while balancing the amount of material required to meet the electrical resistance and mechanical strength requirements in the interconnect component 600. In some embodiments, the number of apertures 620 can range, for example, from 1 to 10, wherein aperture 620 has a width of 0.5 to 5 mm, such as a width 622 of 1 to 3 mm, and 1 to 6 mm, such as 3 to 5 mm. Length 624. The apertures 620 can have internal angles that are rounded to maximize durability while allowing the encapsulant to flow.

Figures 7A through 7B show the square as shown in section D in Figure 4 The width of the ruled line 410 yields a vertical cross-section of the exemplary electroformed components 710 and 720. Cross-sections 710 and 720 are similar to electroformed components 150 and 152 of Figure 2B. And presented in Figures 7A through 7B to illustrate further customized features that can be incorporated into the top surface of the metal article of the present invention. In Figure 7A, element 710 has a rectangular cross-section with a top surface 715, where "top" refers to the light incident surface when mounted on a photovoltaic cell. The top surface 715 can be configured to contribute to the optical properties of the grid lines, such as enhancing light reflection and thereby enhancing battery efficiency. In some embodiments, the texturing can be intentional roughness to increase the surface area used to capture light. This roughness can be imparted, for example, by incorporating a textured pattern into the electroformed mandrel. That is, the preformed pattern 110 of FIG. 1 can have a textured pattern formed in the mandrel 100, wherein the top surface 715 can be a surface fabricated by the bottom of the preformed pattern 110. In another embodiment, texturing can be made by the electroforming process itself. In an exemplary process, high plating current can be used for fast electroforming rates, such as on the order of 1 to 3 [mu]m/minute. This rate of rapidity can result in roughened exposed surfaces at the outer surface 105 of the electroformed mandrel 100.

In other embodiments, the top surface of the custom configuration can be in electroforming The specific surface finish that is created after the part is formed. For example, Figure 7B shows an overplating element 720 having a coating 722 on its top surface 725. Coating 722 can include one or more metal layers including, but not limited to, nickel, silver, tin, lead tin, or solder. Coating 722 can, for example, produce a smooth surface to improve the reflectivity of rounded top surface 725. Application of the solder as a coating to the top surface 725 or 715 in addition to providing optical benefits may also assist in supporting solder backfilling for bonding.

Although element 710 is shown as having a rectangular cross section and components 720 is shown as having a rectangular base and a rounded top, but other cross-sectional shapes such as hemispherical or elongated rectangles with rounded chamfers may be employed. These cross-sectional shapes may be the same throughout the metal object or may vary between different regions of the metal object Chemical. Any curved or rounded edge of the top surface can be used to deflect incident light to the battery or, if within a standard solar cell module, to reflect light to support total internal reflection. The surface can be coated with a highly reflective metal such as silver or tin to enhance both deflection and reflection, thereby reducing the effective grid shadow area to less than its footprint.

Figure 8 shows a top view of an embodiment of another metal object 800, Show other features that can be customized. Metal object 800 has intersecting grid lines 810 and 820 that form a grid configuration on more than half of metal object 800, with intersecting elements 830 and 840 at the ends of the grid. The ruled line 810 has a width that is non-uniform along its length that is designed into the electroformed mandrel from which the metal article 800 is fabricated. In the embodiment of Figure 8, the width 812a is smaller than the width 812b of the interconnect element 840 that is the current sinking end of the battery. The increased width 812b accommodates the higher current at this end as the metal object concentrates current across its surface. Therefore, the increased width 812b reduces the resistive loss. In the region of the increased width as described above, the height of the checkered line 810 can also be adjusted as needed.

The amount of non-uniformity over the length of the checkered line can be designed to Maintain the required fill factor for photovoltaic cells. For example, FIG. 9 shows an exemplary linear grid line 900 having a nominal width 910. The nominal width 910 can be, for example, 50 to 300 [mu]m. In this embodiment, near the end of one of the checkered lines 900, the width 908, such as away from the interconnected region 940, can be reduced by 10 to 30% compared to the nominal width 910. The width 912 near the interconnected region 940 can be increased by 10 to 30% compared to the nominal width 910. Therefore, the checkered line 910 is tapered symmetrically, so that the width of one end is reduced and the width of the other end is increased, resulting in a whole length A fill factor with the same grid width of the nominal width.

In some embodiments, the uneven width of Figures 8 and 9 can be in a square The length occurs continuously, or in other embodiments may occur on one or more portions. In other embodiments, the width of the checkered line 810 can be increased and decreased over different portions rather than having a single ramp rate. In addition, features having a non-uniform width along the length may be present in one, some, or all of the checkered lines.

Turning to Figure 8, grid lines 810 and 820 show the characteristics of another design. In the section, the lengthwise contour also exhibits a shape change in addition to the width. In FIG. 8, the checkered lines 810 and 820 are configured to have an allowable checker line that expands in the length direction, thereby serving as a non-linear pattern of the expanded section. The patterns are formed by creating an electroformed mandrel of metal object 800. In the embodiment of FIG. 8, both of the checkered lines 810 and 820 have a wavy pattern oriented parallel to the plane of the metal article 800 to present the metal object for bonding to the flat surface of the photovoltaic cell. The wave pattern can be configured, for example, as a single wave or other curved shape or geometry. The wave pattern provides an extra length between the solder joints to allow the metal object 800 to expand and contact, such as providing strain relief for the difference in coefficient of thermal expansion (CTE) between the metal object and the bonded semiconductor substrate. For example, copper has a CTE that is about five times that of bismuth. Thus, during the heating and cooling steps involved in manufacturing the subassembly into the final solar cell, the copper metal object that is lead welded to the tantalum substrate will experience significant strain.

The wave pattern is designed to allow the metal object 800 to fully expand and Shrinkage reduces or eliminates problems such as undercuts or breaks that occur due to CTE differences. The size of the expansion section is selected to accommodate the CTE difference of the particular material used. In some embodiments, the wave pattern can have, for example, 200 to 300 The amplitude of μm and the wavelength of 1 to 10 mm provide an extra length compared to a fully linear segment. The expansion section can also provide a lower weld spot size, thereby reducing shadowing due to the reduced strain requirements requiring less weld strength. The lower joint size also supports larger bond process windows, thereby improving manufacturability and cost. Note that although all of the grids 810 and 820 are configured as expansion sections in FIG. 8, in other embodiments, only certain grid lines may be configured as expansion sections. In still other embodiments, only a portion of a single grid line can be configured as an expansion section while the remaining length is linear.

10A to 10E are each of the expansion sections in other embodiments Top view of the configuration. In these figures, the metal grid lines are shown as a single line for simplicity. Further, although only a portion of the checkered lines are displayed, the entire checkered lines may have the same pattern, or the rest of the checkered lines may have different patterns and the width may vary. In FIG. 10A, the bus bar 1010a has a wave pattern, and the cross member 1020a is linear. This design provides one-dimensional CTE stress relief in the direction of bus bar 1010a. The point at which the bus bar 1010a intersects the cross member 1020a should be referred to as the intersection 1030a. Pad 1040a represents a silver, tin or similar pad on a semiconductor wafer to be attached to bus bar 1010a. The pads 1040a are shown as discrete faces in these figures; however, in other embodiments, they may be lines that extend partially or continuously across the semiconductor wafer. In FIG. 10A, pad 1040a is located between intersections 1030a. In other embodiments, the pad 1040a can be positioned to align with the intersection 1030a, or otherwise positioned over the checkered lines 1010a and 1020a.

Figure 10B is consistent with Figure 10A, but the bonding region 1050b has been formed On the bus bar 1010b. Bonding region 1050b is provided for bonding to pad 1040b Increased surface area, such as to increase bond strength and increase manufacturing tolerances. The bond region 1050b can be configured, for example, as a circular pad as shown, or a post or other shape extending from the bus bar 1010b. Note that in Figures 10A and 10B, the directions of the expansion members are interchangeable. That is, the cross members 1020a/b can be configured to have a wave pattern, while the bus bars 1010a/b can be linear.

In FIG. 10C, both the bus bar 1010c and the cross member 1020c It is configured as an expansion section, thereby allowing two-dimensional stress relief. The bus bar 1010c is bonded to the pad 1040c between the intersections 1030c. Both the bus bar 1010c and the cross member 1020c have a wave pattern in which the period 1011c of the bus bar 1010c is the same as the period 1021c of the cross member 1020c. However, the amplitude 1012c of the bus bar 1010c is different - in this embodiment greater than - the amplitude 1022c of the cross member 1020c. It can thus be seen that the bus bar 1010c and the cross member 1020c can be customized independently of one another. In other embodiments, some of the bus bars 1010c within the metal object may have different amplitudes and periods than the other bus bars 1010c. Similarly, cross member 1020c can have different amplitudes and periods from each other.

Figure 10D shows yet another expansion section configuration in which the bus bars 1010d has an arcuate section 1011d having an intervening linear section 1013d between intersections 1030d. In this embodiment, the cross member 1020d is linear. The transition between the straight section 1011d and the curved section 1013d can be designed to be curved, which promotes the removal of metal objects from the electroformed mandrel and reduces stress points due to the absence of sharp angles. In this embodiment, the straight section 1013d has a length that extends across the pad 1040d. Since the stress will be applied to the ruled line 1010d in only one direction, the straight section 1013d can reduce the amount of strain at the pad 1040d. The straight section 1013d can also reduce the manufacturing tolerances required to align the bus bar 1010d with the pad 1040d. In other embodiments, the bus bar 1010d may also include a straight portion at the intersection 1030d to reduce the stress at the intersection between the checkered lines 1010d and 1020d.

Figure 10E shows another embodiment in which the bus bar 1010e and the crossover The member 1020e has straight sections 1013e and 1023e that alternate between the curved portions 1011e and 1021e. The embodiment of Figure 10E supports the metal article to provide CTE strain relief in the X and Y directions while also providing a vertical joint at intersection 1030e.

Figure 11 is an exemplary metal object for the back side of a solar cell A top view of the piece 1100. In this embodiment, the metal object 1100 has checkered lines 1110 and 1120 that are substantially perpendicular to each other and evenly spaced apart. In other embodiments, the checkered lines 1110 and 1120 may intersect at perpendicular angles and may have varying distances. The checkered lines 1110 and 1120 are configured to have an expanded section along their entire length, but in some embodiments, the checkered lines 1110 and 1120 may be partially or fully linear along one of their equal lengths. The metal article 1100 is horizontal and vertically symmetrical, allowing the photovoltaic cell to rotate in any orientation to connect to adjacent cells. In Fig. 11, the checkered lines 1110 and 1120 each have a width 1112 and 1122 wider than the front side of the battery. For example, the widths 1112 and 1122 may be 0.5 to 2 mm, which is 50 to 300 μm wide compared to the front side ruled line. Therefore, the metal object 1100 can provide two to five times more copper than the front side mesh, and has extremely low resistance and a very small voltage drop. The metal object 1100 can also be made thinner, such as one half of the thickness of a standard battery.

Metal object 1100 can also have a larger side for use as a lead soldering platform boundary. The edge members 1130 and the corner members 1140 forming the perimeter of the metal article 1100 can have the same or different widths as the checkered lines 1110 and 1120. In the embodiment of FIG. 11, pads 1150 are configured at intersections where checkered lines 1110 and 1120 meet the perimeter of metal object 1100 (eg, edge member 1130 and corner member 1140). Pad 1150 provides a larger surface area than grid lines 1110 and 1120 for alignment with the pads on the surface of the solar cell. In this embodiment, the pad 1150 also includes radial struts 1160, such as to provide strain relief at the intersection and additional surface area for bonding.

Figure 12 shows the use of the gold of the invention between two photovoltaic cells An exemplary front-to-back battery interconnection of an object. Battery 1200 has a metal object 1210 mounted on the front side, wherein metal object 1210 includes interconnecting elements 1220 at an edge. Metal object 1210 can be, for example, the metal square of Figure 4 or Figure 8. Interconnect 1220 is bonded to the back side of battery 1250 with metal object 1260 configured to resemble the backside mesh of FIG. Bonding can be achieved, for example, by lead soldering, welding, ultrasonic, conductive adhesive or other electrical bonding methods. The interconnect 1220 is bonded to the bus bar 1270 of the metal object 1260 to achieve a series connection of the batteries 1200 and 1250.

Figure 13 illustrates, in an embodiment, a photovoltaic that can be assembled into a module The assembly of batteries 1310, 1320, 1330, and 1340 is 1300. Four batteries are shown in Figure 13, but any number of batteries, such as 36 to 60, can be used in the module as needed. As described in relation to Figure 12, adjacent battery pairs are joined together. However, in the embodiment of Figure 13, each adjacent battery is rotated 90 from the previous battery. For example, battery 1320 is rotated 90° clockwise from battery 1310 to connect to battery 1330, and battery 1330 is rotated 90° clockwise from battery 1320 to connect To battery 1340. The battery 1310 in FIG. 13 provides the positive terminal 1350 of the module 1300, while the battery 1340 provides the negative terminal 1355. Thus, the grid design disclosed herein can be designed to have symmetry that allows for various orientations on the battery, whereby the batteries within the support module are connected in any order as desired. The batteries 1310, 1320, 1330, and 1340 are assembled to have a gap 1360 with each other, similar to the gaps 651 and 652 of FIG. The gap 1360 allows the entire module to flex and also assists in the flow of the laminate when the final module is encapsulated.

Figure 14 is a solar electric appliance using the metal object as described above. An exemplary flow chart 1400 of a method of pool modules. In step 1410, the metal object is electroformed using a conductive mandrel. The mandrel has one or more preformed patterns in which the metal article is formed. In some embodiments, the metal object is configured to be used as an electrical conduit within a photovoltaic cell. In some embodiments, the metal object can include integrated features to support the connection between the photovoltaic cells of the solar module. In other embodiments, the interconnect features can be separately fabricated and bonded to the metal object. If separated, the interconnect features can be formed, for example, by electroforming or stamping the sheet. At least a portion of the final electroformed metal object is created within the preformed pattern. The metal article has a plurality of electroformed components, such as having a customized feature that can include one or more of: a) a non-uniform width along a first length of the first component, b) a first along the first component a change in the direction of the length of the conduit, c) an expanded section along a first length of the first component, d) a first width different from a second width of the second of the plurality of electroformed components, e) and a plurality of electrical a second height of the second element of the cast component that differs by a first height, and f) a textured top surface. Metal objects can be configured to be used as electrical grids, bus bars, inter-cell interconnects, and pads for photovoltaic cells.

Step 1410 can include making the outer surface of the electroformed mandrel and including Contacting a solution of a metal salt, wherein the first metal can be, for example, copper or nickel. The first metal may form the entire metal object or may form a metal precursor of other metal layers. For example, a salt solution comprising a second metal can be electroplated onto the first metal. In some embodiments, the first metal can be nickel and the second metal can be copper, wherein the nickel provides a barrier to copper diffusion. The third metal may optionally be electroplated onto the second metal, such as a third metal that is nickel plated onto the second metal that is copper, which is plated onto the first metal that is nickel. In this three-layer structure, the copper conduit is encapsulated with nickel to provide a barrier to prevent copper contamination into the semiconductor device. The electroforming process parameters in step 1410 can be, for example, a current between 1 and 3000 A/m2 (ASF) and a plating time between, for example, 1 minute to 200 minutes. Other conductive metals may be applied to enhance adhesion, improve wettability, act as diffusion barriers or improve electrical contact such as tin, tin alloys, indium, indium alloys, niobium alloys, nickel tungstate or cobalt cobalt tungstate.

After forming the metal object, the metal object is separated from the conductive mandrel into a self-standing single piece in step 1420. This separation may involve lifting or peeling the article from the mandrel, such as by hand or by means of a tool such as vacuum processing. Peeling can also be facilitated by using interconnecting components, such as component 600 of Figure 6, as a handle for touching and lifting the metal object. In other embodiments, the removal may include thermal or mechanical shock or ultrasonic energy to assist in releasing the fabricated part from the mandrel. The ready-to-stand metal object is then formed into the photovoltaic cell or other semiconductor device through the attached and electrically coupled articles as described below. Transferring the metal article to each manufacturing step can be performed without the need for a support element.

In step 1430, the metal object is mechanically and electrically coupled to the semiconductor Body substrate. Step 1430 can include coupling the front grid to the front side of the semiconductor wafer and the back grid to the back side of the wafer. The coupling can be lead soldering, such as manual or automated lead soldering. Solder can be applied to specific points, such as silver pads that have been printed onto the wafer. In some embodiments, the solder has been pre-applied to all or some of the metal objects, such as by electroplating or dipping. The pre-applied solder can then be backfilled during the coupling process of step 1430. In other embodiments, the solder may be an active solder and may support bonding at the unmetallized portion of the wafer, as applied on August 21, 2013, "Using Active Solder to Couple Metal Objects to "Using an Active Solder to Couple a Metallic Article to a Photovoltaic Cell" is described in the U.S. Provisional Patent Application Serial No. 61/868,436, the disclosure of which is incorporated herein by reference. .

In step 1430, for example, ultrasound, infrared, heat can be utilized Rod or rapid thermal processing techniques bond metal objects to the semiconductor. Bonding can be performed at one contact at a time, or once in the area of the wafer or on the entire wafer. The metal article can include an expansion section to reduce bending or fracture that can be caused by thermal stresses induced during the bonding process.

The semiconductor wafer can be subjected to other processing before or after step 1430 Steps such as applying an anti-reflective coating. The particular coating will depend on the type of battery being fabricated and may include, for example, a dielectric anti-reflective coating such as a nitride, or a transparent conductive oxide such as indium tin oxide.

The prepared photovoltaic cell is then connected in step 1440. together. The interconnections can be implemented in accordance with the related description of Figures 12 and 13 to achieve a front-to-back series connection. In other embodiments, the front-to-front and back-to-back connections are possible. Route the batteries in parallel.

In step 1450, the module assemblies are laminated together. In some In an embodiment, the assembly can include a substrate sheet, such as a polyvinyl fluoride (PVF) film, having a laminate (e.g., EVA) placed onto the substrate sheet. A photovoltaic cell was placed on the EVA sheet and another EVA sheet was placed on top of the cell. Finally, the glass piece is on the top EVA sheet. The entire layered stack was placed in a laminator where heat and vacuum were applied to laminate the assembly. To complete the module, route the battery's electrical connections to the junction box.

It can be seen that the self-standing electroformed metal object described in this paper is suitable for Various battery types are available and can be inserted at different points within the manufacturing sequence of the solar cell. Additionally, electroformed electrical conduits can be used on the front or back surface of the solar cell or both. Moreover, while the embodiments herein have been described primarily for photovoltaic applications, such methods and apparatus are also applicable to other semiconductor applications, such as rewiring layers (RDL) or flexible circuits. Furthermore, the flowchart steps can be implemented in a different order and can include other steps not shown. Although described for full size batteries, they can also be applied to half or quarter size batteries. For example, a metal object design may have a layout that accommodates a battery that has only one or two chamfered corners instead of being chamfered in four corners of a single-crystal full-quasi-square.

Although described in detail with respect to specific embodiments of the invention The book, but it will be appreciated that those skilled in the art can readily devise alternatives, variations and equivalents of the embodiments. These and other modifications and variations of the present application can be implemented by those skilled in the art without departing from the scope of the invention, which is more specifically described in the accompanying application. In the range of interest. In addition, those skilled in the art will understand that the above description is by way of example only and is not intended to limit the invention.

400‧‧‧Metal objects

402‧‧‧Semiconductor substrate

410, 420‧‧‧ grid lines

412, 422, 432, 442‧‧ ‧ width

430, 440‧‧‧ interconnection components

450, 455‧‧‧ edge members

Claims (29)

A method of forming an electrical component for a photovoltaic cell, the method comprising: electroforming a metal object on a conductive mandrel, wherein the conductive mandrel has an outer surface comprising at least one preformed pattern, wherein the metal object Included in the plurality of electroformed elements formed by the preformed pattern; and separating the metal object from the conductive mandrel, wherein the plurality of electroformed elements are interconnected such that the metal object is from the conductive core Forming a single piece of self-standing workpiece when the shaft is separated; wherein the plurality of electroforming elements are assembled as an electric conduit for one of the light incident surfaces of the photovoltaic cell; wherein the plurality of electroforming elements comprise a first component that is assembled with a first expansion section along at least a portion of a first length of the first component, the first expansion section having a semiconductor selected to receive the metal object and the photovoltaic cell a dimension of a difference in thermal expansion coefficient between the substrates, wherein the first expansion section is assembled into a wave pattern; and wherein the first component further comprises a plurality of bonding regions, the first expansion section Bonding between these regions. The method of claim 1, wherein the first component has a non-uniform width along the first length of the first component. The method of claim 2, wherein the non-uniform width is tapered along a width of one of the first lengths. The method of claim 3, wherein the tapered width faces the photovoltaic cell One of the current sinking ends is increased. The method of claim 1, wherein the first component has a change in direction of the conduit along the first length of the first component. The method of claim 5, wherein the first component is a bus bar, and the conduit direction change is grouped to be bent near one of the corners of a pseudo-square photovoltaic cell. The method of claim 1, wherein the first expanded section has a geometry that is oriented in a plane parallel to one of the photovoltaic cells. The method of claim 1, wherein the wave pattern comprises one wavelength of 1 mm to 10 mm and an amplitude of 200 μm to 300 μm to accommodate the difference in thermal expansion coefficient between the metal object and the semiconductor substrate of the photovoltaic cell. The method of claim 1, wherein the first component has a first width that is different from a second width of one of the plurality of electroformed components. The method of claim 1, wherein the first component is a bus bar and the bus bar is positioned adjacent a perimeter of the metal object. The method of claim 1, wherein the plurality of electroformed elements further comprise an inter-cell interconnect at an edge of the metal object, and the inter-cell interconnect includes an aperture extending through one of its thicknesses. The method of claim 11, wherein the pores are a plurality of pores or slits. The method of claim 1 wherein the thickness of one of the inter-cell interconnects comprises a height that is different from a first height of one of the plurality of electroformed components. The method of claim 1, wherein the first component has a textured top surface. The method of claim 14, wherein the texturing comprises an intentional roughness. The method of claim 1, wherein the plurality of electroformed components further comprise a second component that is associated with a second expansion section along at least a portion of a second length of the second component, and wherein The first and second expansion sections allow for two-dimensional stress relief. The method of claim 16, wherein the first and second components are grouped into intersecting checkered lines. The method of claim 16, wherein the first expansion section has a different amplitude and period than the second expansion section. The method of claim 1 wherein the plurality of electroformed elements further comprise edge members forming a perimeter of the metal article. The method of claim 19, wherein the plurality of electroformed components further comprise a pad at a node where the first component meets the perimeter, and wherein the pad has a first portion at the node The component is a large surface area. The method of claim 1, wherein the bonding region has a bonding region width greater than a first width of the first component. A method of forming an electrical component for photovoltaic cells, the method comprising the steps of: electroforming a metal object on a conductive mandrel, wherein the conductive mandrel has an outer surface comprising at least one preformed pattern, wherein The metal article comprises a plurality of electroformed components formed by the preformed pattern; Separating the metal object from the conductive mandrel, wherein the plurality of electroformed components are interconnected such that the metal object forms a single piece of self-standing workpiece when separated from the conductive mandrel; wherein the plurality of self-standing workpieces; The electroformed component is assembled as an electrical conduit for one of the light incident surfaces of the photovoltaic cell; wherein one of the plurality of electroformed components has a first height and one of the cells is mutually And one of the plurality of electroformed components and a second component of the plurality of electroformed components being a grid line for one surface of the photovoltaic cell, the second component having a second height and a lengthwise profile, the length The directional profile includes an expansion section along at least a portion of a second length of the second component, wherein the expansion section is configured to accommodate a difference in thermal expansion coefficient between the metal object and a semiconductor substrate of the photovoltaic cell And wherein the first height is less than the second height. The method of claim 22, wherein: the first component has a first width; the second component has a second width; and the first width is greater than the second width. The method of claim 22, wherein the first height of the first component comprises a thickness of one of the first components, and the first component comprises an aperture through one of its thicknesses. The method of claim 22, wherein the lengthwise profile comprises a tapered width along one of the second elements. The method of claim 22, wherein the expansion segments are grouped into a wave diagram case. The method of claim 22, wherein the lengthwise profile comprises a change in direction of the conduit along one of the second lengths of the second component. The method of claim 22, wherein the plurality of electroformed components further comprise a third component that is assembled with an expansion section along at least a portion of a third length of one of the third components, and wherein The expanded sections of the second and third elements permit two-dimensional stress relief. The method of claim 22, wherein the second component further comprises a plurality of bonding regions, and the expansion segment is between the bonding regions.