WO2015148178A1

WO2015148178A1 - Device and method for forming solder joints in photovoltaic components

Info

Publication number: WO2015148178A1
Application number: PCT/US2015/020877
Authority: WO
Inventors: Patrick M. KELLEHER; Ryan S. Gaston; Robert L. Grove; Pearl M. MOODY; Thomas L. II WOODS; Narayan Ramesh; Ryan N. POWELL
Original assignee: Dow Global Technologies Llc
Priority date: 2014-03-28
Filing date: 2015-03-17
Publication date: 2015-10-01

Abstract

A process comprising; (a) aligning one or more terminals of an electrical component that has geometry constraints with one or more bus bars of a photovoltaic component; (b) pre~feeding flux and solder to a tip of a soldering iron; and (c) connecting one or more of the one or more terminals of the electrical component to one or more busses of the one or more bus bars of the photovoltaic component.

Description

DEVICE AND METHOD FOR FORMING SOLDER JOINTS IN PHOTOVOLTAIC

COMPONENTS

FIELD

[0001] The present teachings provide a device and method for forming a solder connection in a photovoltaic component and more specifically connecting a bypass diode in a photovoltaic module,

BACKGROUND

[0002] Photovoltaic arrays, generally, are created by combining a plurality of photovoltaic components together (e.g., photovoltaic modules). Each of the plurality of photovoltaic components are electrically connected so that energy can flow through the photovoltaic components and eventually to an inverter to provide electricity to desired location. Each of the photovoltaic components includes one or more components that assist in harvesting energy and/or directing energy from one location to another location. These components are electrically connected within the photovoitaic components and these electrical components are typically custom made so that the electrical components can be installed within the electrical component to perform a desired function. However, custom made parts may be expensive, have supply issues, work in one component and not in other components, or a combination thereof. Furthermore, many electrical components that are available are surface mounted components. The electrical components when mounted using surface mounting techniques have low strain and fatigue stress and may fail when used in a solar component and subject to thermal expansion. The electrical components typically are connected to an existing surface and do not provide any structural integrity to the existing surface and the electrical components are subjected to low amounts of stress due to support of the existing surface. Further, surface mounted componentry when subjected to high heat conditions may fail and/or be damaged and may have geometry constraints that prevent the surface mounted componentry from being connected within photovoltaic components using techniques other than surface mounting.

[0003] Examples of some devices and methods for forming connections in a solar module may be found in Patent Application Publication No, 2009/0014057 and 2009/0308430; European Application Publication No, EP1983578 A2; Korean Patent Application iMo. KR2012 068399A; and Japanese Patent Application No. JP2006/351706A and JP2008/147555A all of which are incorporated by reference herein for all purposes.

[0004 St would be attractive to have a device and process for installing standard components, surface mounied electrical components, or both within a photovoltaic component. It would be attractive to have a device and method that allows for connecting a standard component, a surface mounted electrical component, or both with a constrained geometry within a photovoltaic component, ft would be attractive to have an electrical component and a connection for connecting the electricai component within a photovoltaic component that withstands fatigue and creep strain for 10 years or more and preferably 20 years or more. What is needed is a device and method for connecting a terminal of an electricai component directly to the surface of a bus bar of a photovoltaic component. What is needed is a device and method for installing a standard diode within a photovoltaic module.

SUMMARY

[0005] The present teachings meet one or more of the present needs fay providing; a device comprising: (a) an assembly comprising: (1 ) one or more nests and (2) one or more ledges connected to the one or more nests; (b) one or more placement devices that completely and/or partially suspend an electrical component with a constrained geometry above the assembly so that an electrical component can be formed; (c) a soldering iron; and (d) a soldering wire; wherein the soldering iron is located between the soldering wire and the electricai component.

[0008] The present teachings provide; a process comprising (a) aligning one or more terminals of an e!ectricai component that has geometry constraints with one or more bus bars of a photovoltaic component; (b) pre-feeding flux and solder to a tip of a soldering iron; and (c) connecting one or more of the one or more terminals of the electrical component to one or more busses of the one or more bus bars of the photovoltaic com onent.

[0007] The teachings herein surprisingly solve one or more of these problems by providing a device and process fo installing standard components, surface mounted electricai components, or both within a photovoltaic component. The teachings herein provide a device and method that allows for connecting a standard component, a surface mounted electrical component, or both with a constrained geometry within a photovoltaic component. The present teachings provide an electrical component and a connection for connecting the electrical component within an photovoltaic component that withstands fatigue and creep strain for 10 years or more and preferably 20 years or more. The teachings herein provide a device and method for connecting a terminal of an electrical component directly to the surface of a bus bar of a photovoltaic component. The teachings herein provide a device and method for installing a standard diode within a photovoltaic module. BRIEF DESCRIPTION OF THE DRAWINGS

100083 RG>- 1 illustrates a side view of one example of an assembly;

[0009] FIG. 2 illustrates a close-up view of an anode terminal in the assembly of FIG, 1 ;

[0010] FfG. 3 illustrates an example of an electrical component extending between and connecting bus bars;

[0011] FIG. 4 illustrates an example of a photovoltaic module Include an electrical component;

[0012] FIG. 5 illustrates an example of a photovoltaic array including a plurality of photovoltaic modules of FIG. 4;

[0013] FIG, 6 illustrates a flow diagram of a non-destructive test method;

[0014] FIG. 7 illustrates a 100x microscopic image of a joint; and

[0015] FIG, 8 illustrates a 5000.x microscopic image of the joint of FIG, 7.

DETAILED DESCRIPTION

[0016] The explanations and illustrations presented herein are intended to acquaint others skilled in the art with the teachings, its principles, and its practical application. Those skilled in the art may adapt and apply the teachings In its numerous forms, as may be best suited to the requirements of a particular use. Accordingly, the specific embodiments of the present teachings as set forth are not intended as being exhaustive or limiting of the teachings. The scope of the teachings should, therefore, be determined not with reference to the above description, but should instead be determined with reference to the appended claims, along with the full scope of equivalents to which such claims are entitled, The disclosures of all articles and references, Including patent applications and publications, are incorporated by reference for all purposes. Other combinations are also possible as will be gleaned from the following claims, which are also hereby incorporated by reference into this written description.

[0017] The teachings herein provide an improved device and method of installing components within a photovoltaic component. A plurality of photovoltaic components (e.g., photovoltaic modules and integrated flashing pieces) are combined together to form a photovoltaic array that collects sunlight and converts the sunlight to electricity. The photovoltaic modules of the teachings herein may be used with a housing that contains all of the individual solar modules that make up a photovoltaic array. Preferably, the photovoltaic array taught herein is free of a separate structure that houses all of the solar modules that make up a solar array. More preferably, each individual solar module may be connected directly to a structure such as a roof and each of the individual solar moduies is electrically connected together so that a solar array is formed (i.e., a building integrated photovoltaic (BIPV)). [0018] The plurality of photovoltaic components may be configured in any manner so that each of the plurality of photovoltaic components may be electrically connected. The photovoltaic components may be comprised of a plurality of laminated layers and each of the layers may expand at different rates (i.e., have a different coefficient of thermal expansion (CTE)). The photovoltaic component may include one or more potting wells so that one or more electrical components may be electrically connected to electrical circuitr and be laminated within the photovoltaic component. Preferably, at least one of the layers of the photovoltaic components may be electrical circuitry and the electrical circuitry may at least partially be laminated within the photovoltaic component. The electrical circuitry may be stressed, strained, subjected to fatigue, or a combination thereof during repeated thermal expansion and contraction resulting from environmental changes in temperature by the one or more laminated layers expanding and contracting at different rates {i.e., having a different coefficient of thermal expansion). Each of the individual photovoltaic components may be electrically connected to an adjacent photovoltaic component such as a photovoltaic module by electrical circuitry. The electrical circuitry may be one or more ribbons, a positive bus bar, a negative bus bar, a connector, an integrated flashing piece, one or more diodes, one or more electrical components, or a combination thereof. The ribbons as discussed herein may be any wire, electrical conductor, or both that extends within a photovoltaic component. The ribbons may be about the same width as the terminals of the electrical components. The width of the ribbons may be sufficiently large so that solder, flux, or both do not extend beyond the edges of the ribbon during formation of a joint. The ribbons may be made of any material that conducts power, electricity, or both. The ribbons may include copper, silver, brass, beryllium, nickel, gold, steel, iron, or a mixture thereof. The ribbons may be coated with a metal that has a different (e.g., higher or lower) conductivity than the base material, a lower melting point, less sensitive to oxidation, a less expensive material than a base material, a more expensive material than a base material, or a combination thereof. For example, the ribbons may be copper and coated with tin. Preferably, the electrical circuitry are ribbons that are joined to a connector that extends between and/or receives a connector that extends between and connects two or more adjacent photovoltaic components, More preferably, the electrical circuitry of the photovoltaic components may be one or more bus bars, one or more ribbons, or both that connect two or more photovoltaic components together. The electrical circuitry may extend from cell to cell, photovoltaic module to photovoltaic module, cell to a photovoltaic module, photovoltaic module to integrated flashing piece, or a combination thereof. For example, the joint (e.g., solder fillet) formed by the device and teachings herein may join together a bus bar of a photovoltaic component with an electricai component so that the electrical component is physically and electrically connected within the photovoltaic module. In another example, a bus bar of a photovoltaic module and a terminal of a diode may be joined together by the teachings herein so that the diode is a low resistance electrical and mechanical connection between two adjacent ends of a bus bar. The joint formed may form a bridge between two bus bar portions; may have sufficient strength to withstand repeated thermai expansion and contraction of the bus bar, the photovoltaic component, the electrical circuitry, the laminated layers, or a combination thereof; movement of the connectors of the photovoltaic component by a connector of an adjacent photovoltaic component; or a combination thereof. Preferably, the component is a diode that is installed within a photovoltaic module and forms a bypass on one or more bus bars of the photovoltaic module and prevents reverse biasing within the photovoltaic component.

[0019] The photovoltaic module may function to capture energy from suniight and translate the energy to an inverter to create electricity. The photovoltaic module may include one or more cells that function to capture energy from sunlight. The one or more cells may be electrically connected, may be electrically connected to one or more bus bars, or both. The one or more cells may be made of any materia! that functions to capture energy from sunlight that can be converted into electricity. The one or more ceils may be connected by one or more ribbons, to one or more bus bars, or both. The one or more ribbons, one or more busses, or both may connect ceil to cell, may run th length and/or width of a photovoltaic component (e.g. the photovoltaic modules), or both. Preferably, as discussed herein the bus bars are a larger ribbon that runs the length of the photovoltaic module and the ribbons of the cells connect to the bus bars so that the bus bars can transfer energy from photovoltaic com onent to photovoltaic component and ultimately to the inverter. The bus bars or bus ribbons as discussed herein may function to collect energy from the cells of the photovoltaic module and transmit the energy from one photovoltaic component to another one of the one or more photovoltaic components. The bus bars may terminate at a connector that functions to connect one photovoltaic component to an adjacent photovoltaic component. Preferably, at least one of the one or more bus bars of each photovoltaic component and more preferably each photovoltaic module include an electrical component having geometric constraints along a length of the bus bar. More preferably, the electrical component is a diode that is connected to one or more of the bus bars.

[0020] The diode may foe any diode that functions to prevent reverse flow of power, to generate a unidirectional fiow of power, protect the photovoltaic component from a power surge, regulate the flow of power, create a bypass for power to flow during predetermined conditions, or a combination thereof. The diode ma protect the photovoltaic components from an over voltage condition. The diode may protect the photovoltaic components from a spike in voltage. The diode may be a failure point during a voltage surge so that the other components of the photovoltaic component are protected and only the diode fails. The diode may be an avalanche diode, a zener diode, a schottky diode, a field effect transistor, or a combination thereof. The diode, the electrical component, or both may be a surface mounted component.

[00213 The electrical component (e.g., diode) may include one o more terminals. Preferably, the electrical component may Include at least one terminal extending from an anode side (i.e., anode terminal) and at least one terminal extending from a cathode side (i.e., cathode terminal ). The terminals may be cop!anar with a package of the electrical component. One or more terminais on one side may extend coplanar with the package and one or more terminals on an opposing side of the package may extend at an angle from the package, dow from the package, from a top of a package to a bottom of a package, or a combination thereof. One or more of the terminals may extend at a downward angle towards a bus bar and a portion of the terminal proximate to the bus bar may extend away from the bus bar. The anode terminals, cathode terminals, or both may extend coplanar with the package. Preferably, the cathod terminal is coplanar with the package. The anode terminal may extend at an angle. The package may have two terminals that extend from each side (i.e., two cathode terminals and two anode terminals). The package, the electrical components, the terminals, or a combination thereof may have geometric constraints.

[002:2] The geometric constraints may function to prevent a soldering wire, a soldering iron, or both from contacting one or more of the terminals, the bus bars proximate to the terminals, or both. The geometric constraint may be a constraint created by the position of the package relative to the terminals. The geometric constraint may prevent the soldering iron from transferring thermal energy (e.g., heat) directly to the terminals, the bus bars, or both before a joint is formed. The geometric constraint may prevent the terminals on both sides of the electrical component from: contacting the bus bars. The one or more terminals may be subject to deformation due to the geometric constraints of the electrical component. The one or more terminals, the bus bars, or both may be supported within an assembly that assists in forming a joint, a soldering fillet, or both between the terminals and the bus bars,

[0023] The assembly may function to support the electrical component, the bus bars, the terminais, or a combination thereof during a formation of a joint and/or soldering fillet. The assembly may assist in aligning the terminals to the bus bars. The assembly may prevent the bus bars, the terminals or both from deforming during formation of a joint. The assembly may assist in creating joints of uniform size and shape with each formation. The assembly may include one or more nests, one or more ledges, or both.

[0024] The nest may function to support the diode, the electrical component, the package, or a combination thereof. The nest may function to elevate the package so that the terminais extend therefrom and into contact with the bus bars. The nest may align the package relative to the bus bars, the terminais relative to the bus bars, or both. The nest may create a recess under the package so that the soldering fillet when formed can encapsulate all or a portion of the terminals, the bus bars, or both. The nest may create a predetermined distance between the terminals and the bus bars. The predetermined distance may determine the thickness of the joint. The nest may accommodate the terminals extending from different locations, having different orientations, or both. The nest may be made of any materia! that supports the electrical component, the package, or both during assembly of the terminais to the bus bars. The nest may have insulating characteristics so that heat is prevented in being transferred to the package of the electrical component, The nest may be made of a material with !ow conductivity and/or coated with a materia! with low conductivity so that heat is not transferred from the bus bars, the terminals, the soldering iron, the pre~feed, or a combination thereof into the nest and/or so that the bus bars, the terminals, the pre-feed, or a combination thereof are not coo!ed. The nest may be made of, coated with, or both a material that is resistant to corrosion from acid in the flux; sticking by the so!der. the flux, the terminals, the bus bars, or a combination thereof; or both. Preferably, the nest is made of and/or coated with ceramic, a heat treated metal, stainless steel, nickel, chrome, or a combination thereof. The electrical component, the package, or both may be free of contact with the nest, may be suspended above the nest, or both during assembly. The nest may extend between one or more Sedges fhaf support the terminals, th bus bars or both,

[0025] The one o more ledges may support the bus bars, the terminals, or both; prevent deformation of the bus bars, the terminals, or both; prevent solder and/or flux from migrating away from the terminals, the bus bars, or both: align the bus bars relative to the terminals; or a combinatio thereof. The one or more Sedges may maintain and/or align the bus bars₍ terminals or both on the anode side with the bus bars, terminals, or both on the cathode side so that the terminals are copianar. The one or more Sedges alone or in conjunction with the nest may prevent lateral movement, longitudinal movement, or both of the one or more bus bars so that a standard space is maintained between the bus bars. The Sedges may be made of the same materials listed for the nest and preferably the ledges and the nest are made of the same material. The one o more bus bars, the one or more nests, or both may work in conjunction with a placement device.

[0026] The one or more placement devices may move one or more electrical components into the assembly so that the one or more electrical components may be Installed in a photovoltaic component, The one or more placement devices may verticaSly align, horizontally align, or both the electrical components within the system, the assembly, or both. The one or more placement devices may maintain a position of the electrical components until assembly of the electrical component within the system is complete. The one or more placement devices may suspend the one or more eiectrical components above the assembly so that the electrical component is free of contact with the nest, the one or more ledges, or both. The one or more placement devices may move the one or more eiectrical components by gripping the electrical components, suction, magnetism, or a combination thereof. The one or more placement devices may move and align the eiectricai component so thai the terminals of th electrical components align with the bus bars of the photovoltaic components. The placement devices may prevent the terminals, the bus bars, or both from contacting so that deformation is prevented. The placement device may maintain the terminals a predetermined distance from the bus bars so that the soldering iron may create a joint that connects the terminals to the bus bars,

[0027] The soldering iron may function to heat the terminals and/or bus bars, pre-heat the terminals and/or bus bars, melt solder, apply solder, apply flux, or a combination thereof. The soldering iron may contact solder and flux and apply the solder and flux to the predetermined distance between the terminals and the bus bars. The soldering iron may have sufficient amount of power so that the soldering iron maintains at least a predetermined temperature or higher, maintains the solder in a liquid form when the solder is pre-fed, when the solder is being applied to form a joint, or both. The soldering iron may be heated before solder, flux, or both are moved into contact with the soldering iron; before contacting the terminal, the bus bars, or both; before a pre-feed is formed; or a combination thereof. The soldering iron may be pre-heated so that the soldering iron maintains a minimum temperature. The soldering iron may be overheated (e.g., heated to a temperature of about 25 °C above a soldering temperature) before the soldering iron is contacted by the solder, the flux, is moved into contact with the ribbons, is moved into contact with a terminal, forms a joint, or a combination thereof. For example, if soldering has a set point of heating is about 400 then before the soldering process is initiated the soldering iron is over heated to a temperature of about 425 °C. The soldering iron may be generally straight so that the soldering Iron applies solder to a predetermined location to create a joint. The soldering iron includes a tip where the solder, flux, or both are transferred from the solder iron to the location of interest. The soldering iron may only be able to apply solder and/or flux to a predetermined location. The soldering iron during application of solder, flux, or both may be located between the predetermined location and the solder wire, the flux applicator, o both. Preferably, the ti of the soldering iron Is located closest to the predetermined location and the solder wire, the flux applicator, or both are located distal relative to the tip of the soldering iron. The soldering iron during use may extend to a predetermined location and assume a substantially static position and flux, soldering wire, or both may be moved into contact with the soldering iron so that the solder and flux are applied to the predetermined location.

[0028] The soldering wire when liquefied or molten may function to form a joint between the terminals and the bus bars. The soldering wire may be any material that joins two highly conductive materials together. The solder wire may be made of any material with a liquidus point below about 400 ^SC. The solder may be any meltable and f!owable material. Preferably, the solder is metal. The solder wire may include tin, silver, copper, gold, steel, iron, indium, lead, bismuth or any other highly conductive metals. The solder wire may include additives, refining elements, or both. Preferably, the solder wire includes tin, silver, and copper at a near eutectic composition. More preferably, the solder is a lead free alloy. The solder may form a connection between the bus bars and the terminals so that energy may extend from the bus bar to the terminal and vice versa. The solder may fill in the predetermined distance between the terminal and the bus bar. The solder may form a bridge between the terminal and the bus bar. The soider may be applied with f ux, after flux, before flux, or a combination thereof.

[0029] The flux may function to clean one or more components before a joint is formed. The flux may clean the soldering iron, the soldering wire, the terminals, the bus bars, or a combination thereof. The flux may function to remove oxidation and oxide from surfaces to be joined, reduction surface tension between the surfaces to be joined, promote flow of solder between two opposing surfaces, or a combination thereof. The flux may be acidic. The flux may be a liquid that is applied to the soldering iron before or during the melting and flowing of the soldering wire. The flux may be a rosin that part of the solder wire and melted simultaneously with the solder wire, the flux may form a liquid core of the soider, the flux may be mixed within the solder, or a combination thereof. The flux may be placed within an organic gum rosin that carriers the flux. One example of a commercially available flux core solder is available from Aipha Teiecore, sold under the name Alpha Telecore XL-825. The solder wire may have a flux content of about 1 percent by weight or more, preferably about 2 percent by weight or more, or more preferably about 3 percent by weight or more (i.e., about 3.3 percent by weight) flux within the solder wire. The flux may assist in flowing the solder. The flux may clean as the solder flows. The flux may assist in creating a strong joint. The flux, solder, or both may be pre-fed unto the solde iro before the solder iron is proximate to the location to be joined.

[0030] The pre-feed may function to create a bridge between the solder iron and a portion of the electrical component, the photovoltaic component, or both. The pre-feed may create a bridge between the soider iron and a portion of the electrical component with geometry constraints. For example, due to the geometry constraints the soldering iron may not be able to make contact with the terminal, the bus bar, or both and solder and/or flux may be pre-fed to the tip of the soldering iron so that the pre-fed material forms a bridge between the tip of the soldering iron and the terminal, the bus bars, or both. The pre-feed may form a bridge so that the soldering iron is free of direct contact with the terminals, the bus bars, the eieetricai component, the photovoltaic component, or a combination thereof. The pre-fed materia! may transfer heat from the soldering iron to the terminal, the bus bars, or both so that the solder iron, the bus bars, the terminals, or a combination thereof are heated to a predetermined temperature; the temperature difference between the terminals, the bus bars, the soider iron, or a combination thereof reduced to below a predetermined maximum: the soider may flow between the terminals and the bus bars without premature cooling; or a combination thereof. The pre-feed may bridge a gap of about 0.5 mm or more, about 1.0 mm or more, or even about 1.2 mm or more (i.e., about 1.4 mm) between the termina!s and/or bus bars and the soider iron. The pre-feed may form a bridge for a sufficient duration of lime so that the terminals, the bus bars, or both are pre-heated to a pre-determined temperature or more. The pre-feed may assist in forming a bridge for the main feed to transfer from the tip of the soldering iron to the predetermined location so that a joint and/or soider fillet are formed.

[0031] The soider fillet and/or joint may function to mechanicaiiy connect, electrically connect, or both two adjacent structures together. The soider fillet or joint as discussed herein refer to the same connection structure and are used interchangeably. The joint may be entirely located between two adjacent electrical parts of the photovoltaic components. Preferably, the joint is formed between a terminal of an electrical component and a bus bar of a photovoltaic component. The joint may be formed of only material of the soider and may have a composition that is substantially the same as the soldering wire. The joint may include some material from the terminal, the bus bars, or both and there may be some intermetallic mixing. The joint may form intermetailics and/or intermetallic compounds proximate to the surfaces being joined. The intermetailics may be formed at the point of contact between the soider and the bus_: terminal, ribbon, or a combination thereof. The joint may be made of materials that have low electrical resistance. The joint may form a tin/coppe intermetallic compounds. Preferably, at least a portion of the joint has a composition of CueSn§, More preferably, the joint has a sufficient amount of CusSn_sat the interfaces between the buses and the solder joint so that the joint has sufficient strength to resist failure of the terminals and the bus bars, to have good ductility, low brittleness, fatigu resistance, or a combination thereof. The joint may have sufficient fatigue resistance (e.g., repetitive strain) that when the joint is cycled between about 0.01 mm and about 0.2 mm at a temperature of about 125 the joint may resist failure (e.g., cracking) for about 500 cycles or more, preferably about 1000 cycles or more, more preferably about 1500 cycles or more, or even more preferably about 1750 cycles or more. For example, the joint may be placed in a device at a temperature of about 125 ^*C and cycled 0.2 mm every 10 minutes and the joint may resist 1850 cycles. The joint may have sufficient strength that the bus, terminal, ribbon, or a combination thereof may fail before the joint. The interfaces between the buses and the solder joint may have a surface area that includes about 50 percent or more, about 60 percent or more, preferably about 70 percent or more, more preferably about 80 percent or more, or most preferably about 90 percent or more CusSos over the surface area of the interface. The dwe!! time of the soldering iron may be sufficiently long to create CueSns but short enough so that CuaSn is not formed. The joint may include a layer of CueSng o each side of the joint. The thickness of CugSng, the intermetallic connection, or both on each side of the joint may be about 0.1 pm thick or more, about 0.5 pm thick or more, preferably about 1 pm thick or more, or more preferably about 3 pm thick or more. The joint may extend so that the joint covers a portion of the bus, through the overlapping region, and out a second side so that the joint covers a portion of the terminal The joint may have any thicknes so that the Joint has sufficient strength to withstand; repeated tensile and compressive forces as weii as creep strain the bus bar on the anode side being puiled in a first direction and the bus bar on the cathode side being pu!Sed in a second direction, forces created by thermal expansion, forces created by movement of the photovoltaic components relative to each other, or a combination thereof. The joint may be formed in a out 30 seconds or iess, about 20 seconds or iess, about 15 seconds or less, or even about 10 seconds or less. The joint may be formed in about 1 second or more, about 3 seconds or more, or about 5 seconds or more. The joint may have a thickness of about 0.001 mm or more, about 0.005 mm or more, preferably about 0.01 mm or more, more preferably about 0.05 mm or more, or even about 0.1 mm or more. The joint may have a thickness of about 1 mm or less, about 0,75 mm or less, or about 0.5 mm or less. The joint may be substantially as wide as the terminals, the bus bars, or both. The joint may not expand beyond the width of the terminal, the bus bars, or both; however, the joint may extend beyond an end (e.g., length) of the bus bar, the terminal, or both.

[00323 The joint may be formed by solder, flux, or both being applied proximate to a space between the terminal and the bus bars. The solder, flux, or both may move between the terminal, the bus bars, or both by flowing. The flux, rosin, or both may be burned off by the soldering iron, the joint forming process, or both and the solder may flow between terminal, the bus bars, or both. The flow of the solder, the fiux, or both may be due to capillary action. The flow of the solder may be sufficient to extend the length of the overlap region between the terminal and the bus bar or more. A sufficient amount of solder, fiux, or both may flow between the terminal and the bus bar to form a joint there between. The joint as discussed herein may be created using a method and device taught herein.

10033] The method of connecting the terminals to the bus bars, connecting an electrical component within a photovoltaic component, forming a joint, or a combination thereof may use one or more of the following steps which may be performed in an order different than recited herein. An assembiy may be provided. The assembiy may include one or more nests, one or more Sedges, one or more placement devices, one or more soldering irons, one or more flux applicators, one or more soldering irons, or a combination thereof. One or pieces of electrical circuitry for a photovoltaic component may be arranged relative to each other in the assembly and/or by the assembiy. The one or more pieces of electrical circuitry may be aligned with the assembiy, against the nests, on the ledges, or a combination thereof . Preferably, bus bars of the electrical circuitry are aligned on the ledges and against the nest so that longitudinal movement is prevented. The nest, Sedge, or both may prevent lateral movement. The one or more eiectricai components may be moved. The one or more eiectricai components may be connected to a placement device such as an end of an arm tool (EOAT). The one or more eiectricai components may be aligned with the nest, the ledge, or both and vertically moved into a soldering position. The placement device may maintain contact with the electrical component throughout the entire duration of the of the connection process. The placement device may hold the package of the eiectricai component a predetermined distance above the nest, the terminals a predetermined distance away from the ledges, or both. The predetermined distance may determine the height of the joint. The larger the predetermined distance the larger the joint thickness. After the bus bars are aligned, the electrical component is aligned and the solder wire, the solder iron, the flux applicator, or a combination thereof may be moved to a position proximate to the electrical component, the assembly, or both. The soldering iron may be preheated before solder, flux, or both are fed to the soldering iron, a pre-fed solder is created, or both. Solder, flux, or both may be pre-fed to a tip of the soldering iron. The pre-fed solder, flux, or both may be moved so that the pre-fed solder, flux, or both comes info contact with the terminal, the bus bar, is located between the bus bar and terminal, or a combination thereof. The soldering iron may be positioned so that the soldering iron is located between the terminal and the bus bar and the solder wire, the flux applicator, or both so that the tip is the closest connection piece to the point of interest. The soldering wire may be pre-fed to the tip while the soldering iron is a predetermined distance from the point of interest, which the tip is located at a distanc for forming a joint, or a position therebetween. The soldering wire may be pre-fed as the soldering iron is being moved into position so that when the soldering iron is in position the pre-fed solder can create a bridge. The bridge may remain between the soldering iron and the terminal, the bus bars, or both for a sufficient amount of time so that heat is transferred from the soldering iron, a predetermined temperature is achieved, for a predetermined duration, or a combination thereof. Once a predetermined condition is achieved with the bridge, additional solder, flux, or both are fed to the soldering iron and melted so that the solder, flux, or both flow between the bus bars, the terminals, or both. A predetermined amount of solder, flux, or both are applied to form each joint.

[0034] One or more inert gases may be fed to the point of interest. The one or more inert gases may function to prevent oxidation of the bus bars, the terminals, the solder, or a combination thereof during formation of a joint. The inert gas may be fed only during the formation of the joint. The inert gas may be fed across the soldering iron any time the soldering iron is heated, any time soldering is performed, any time soldering is contacting the soldering iron, or a combination thereof. The inert gas may be fed across a formation of a joint, a soldering iron, molten solder, a joint, or a combination thereof. The inert gas may be applied at a rate of about 0.25 L/min, preferably about 0.5 L/min, more preferably about 0.75 L/min, or most preferably about 1 L/min or more. The inert gas may be fed on!y to a iocaiized area. The inert gas may be used to prevent oxidation while a joint is being formed. The inert gas may be nitrogen. After each joint is formed the solder iron may be moved away from the assembly. The joint may be cooled using conduction, convection, forced convection, natural convection, or a combination thereof. The Joint, electrical component, or both may be maintained within the assembiy and the assembiy may be moved aiong the production process so that the assembiy assists in allowing the joint to coo! and maintain integrity. The joint is maintained within the assembly for about 15 seconds or more, preferably about 30 seconds or more, or more preferably about 45 seconds or more. The joint may be removed from the initial assembiy and placed within a second assembly and/or nest so that further process of the bus is performed. The process may foe repeated for the second side of the electrical component, for a second terminal of the electrical component, or both. The process may solder the anode side first and the cathode side second or vice versa.

[0035] The assembly, the solder iron, or both may be cleaned. The assembly, the nest, the ledge, the solder iron, or a combination thereof may be cleaned between formation of each joint. Preferably, at least the nest is cleaned before each joint is formed. Cleaning may be performed using a chemical, abrasion, or both. Preferably, a wire wheel cleans the components between formation of each joint. The solder iron is "retinned" after cleaning to assure the solder predictable fiows off the iron and the flux can further clean the iron after brushing. A portio of the solder wire may be removed between formation of each joint so that cross-contamination is prevented. The so!der iron may be cooled between formation of each joint. The solder iron may be heated between each solder joint so that the solder iron maintains a standard temperature so that heat may be transferred to the terminals, the bus bars, or both, so that the solder iron can compensate for the loss of temperature from the highly conductive materials of the electrical component, or a combination thereof. Formation of the joint may be free of a refiow step. For example, the method may only have one heating step in forming a joint and there is not a subsequent step where the solder is flowed a second time to form the joint.

[0036] The joint, the diode, or both may be tested using one or more non-destructive tests to ensure that the joint, the diode, or both are not damaged, have a sufficient strength to withstand placement within a solar array, or a combination thereof. The diode may be tested to ensure that the diode was not damaged, overheated, or both during the attachment process. The temperature of the diode may be measured as soon as the soldering process is completed. The temperature of the diode may be compared to a look-up table. The temperature of the diode may be measured using a thermometer, infrared, a pyrometer, a thermistor, or a combination thereof, if the temperature exceeds a predetermined temperature then the diode and joint may be rejected. If the predetermined temperature is below a predetermined temperature then the diode and joint are accepted. The predetermined temperature may be about 300 ^eC or less, preferably about 250 ^CC or less, more preferably about 225 X or less, or even more preferably about 200 ^a C or less. Joint integrity, joint strength, or both may be tested in a separate step from the testing of the diode.

[00373 The test method may me a destructive test method, however, preferably the test method is a nondestructive test method. The test method may include one or more of the following steps. The test method may include ihermocycling the joint The joints, diode, buses, or a combination thereof may be thertnocycled at a repeated temperature change of about 60 °C or more, about 85 °C or more, about 105 °C or more, or even about 120 °C or more. For example the joint may be thermocycled from a high temperature of about 85 *C to a low temperature of about -40 X, The Ihermocycling may occur at a frequency of about every 1 hour or more, about 12 hours or more, or every about 24 hours or more. The ihermocycling may last a sufficient duration until the joint fails so that the strength of the joint may be determined. Preferably, the ihermocycling may be interrupted after a predetermined amount of time (e.g., 5 days or more or even 20 days or more) so that the joint may be tested and then the joint may be placed back into the apparatus and thermocycling may be repeated. Repeated ihermocycling cycles and/or starting and stopping the thermocyciing process may allow for the same parts to be tested multiple times (e.g., 5 cycles or more, 10 cycles or more, or even 20 cycles or more). This may allow for less parts to be used to determine joint strength, joint life, or both. The ihermocycling may last a duration of about 5 days or more, preferably about 10 days or more, more preferably about 15 days or more, or even more preferably about 20 days or more. Preferably, after about 20 days or more the integrity of the joint remain is tact A current may be applied across the joint after formaiion of the joint, after thermocycling of the joini, after the joint is produced and normalized to room temperature, or a combination thereof to determine the strength of the joint, if the joint has failed, or both. 100383 The current may be a standard current so that ihe voltage drop across the joint, ihe diode, or both may be measured. The current may be sufficiently large so thai a voltage drop can be measured across the diode, the joint, or both. The current applied to the diode, th joint, or bot may be about 1 Amp or more, about 3 Amps or more, or preferably about 5 Amps or more. The current applied to the diode, the joint, or both may be about 20 Amps or less, about 15 Amps or less, or about 10 Amps or iess. The current may be applied across the joint, the diode, or boih for a sufficient amount of time so that the resistance, voltage drop, or both of the joint, diode, or both may be measured.

[00393 Th measured voiiage drop, resistance, or both may be compared to a look up iable, a known value at the predetermined current, or both. The measured voltage drop, resistance, or both may have a predetermined value where joint failure may be predicted, joint strength is low, thermocycling may damage the joint and/or diode, or a combination thereof. The measured voltage drop when the joint, the diode, or both are acceptable may foe about 1 V or less, preferably about 0.8 V or less, or more preferably about 0.6 V or less. The resistance of the joint the diode, or both are acceptable may be about 5 D or less, preferably about 4 Ω or less, more preferably about 3 Ω or less, or even more preferably about 2.5 Ω or less. The joint, diode, or both may be rejected, fail, or both if the voltage drop and/or resistance exceeds th acceptable limits.

[0040] In one specific example diode terminals are connected to bus bars by a solder joint being created between teach diode terminal and associated bus bar. The solder joint is allowed to cool to room temperature and then is placed in an environmental chamber. The diode and solder joints are thermocyc!ed from 85 *C to -40 ^aC every 24 hours for 20 days, The diodes and solder joints are removed from the environmental chamber and 5 Amps of current are applied between the anode to the cathode of diode. The resistance of the diode and/or voltage drop of the diode between the anode and cathode are measured. The resistance when 3 Ω or less and/or the voltage is 0.6 V or less is accepted and if the resistance is above 3 0 or and/or voltage is above 0,6 V the diode and solder joint is rejected.

[0041] Figure 1 illustrates an assembly 8 for connecting terminals 34 of a diode 32 to bus bars 30 of a photovoltaic component with solder fillets. The diode 32 is moved over a iedge 12 and held above the Iedge 12 by a placement device 14 that maintains the diode 32 centered above the Iedge 12 with a gap sufficient to form the desired joint structure. The diode 32 includes one terminal 34 thai is a cathode terminal 36 and another terminal 34 that is an anode terminal 38, which extends out from the diode 32 and extends downward without contacting the terminals 34. A soldering iron 18 and soldering wire 16 are moved proximate to the terminals 34 of the diode and bus bars 30 so that flux 22 and solder 24 are applied to the solder iron 18 and the flux 22 and solder 24 flow off the solder iron 18 onto the respective terminals 34 of the diode 32 and bus bars 30 of the photovoltaic component forming a "heat bridge" between the solder iron 16. the bus bars 30 and the terminals 34. As illustrated, the heat bridge has been formed between the solder iron 18 and the respective terminals 34 and bus bars 30 so that heat is transferred to the terminals 34 and bus bars 30 before the solder 24 flows in the direction 50 and a solder fillet (not shown) is formed.

[0042] Figure 2 illustrates a close u view of one half of the assembly 8, The diode 32 is located proximate to a iedge 12 of the nest 10 and a terminal 34 extends beyond the Sedge 2. The anode terminal 38 extends over the ledge 12 and downward towards a bus bar 30 of a photovoltaic component (not shown). The soldering iron 18 and soldering wire 16 are moved towards the diode terminal 34 and the bus bar 30, While the soldering iron 8 is located away from the diode terminal 34 the solder wire 16 contacts the soldering iron 18 so that a pre-feed 20 of solder 24 is formed on the tip of the soldering iron 18. When the soldering iron 18 is moved proximate io ihe diode bus 34 the pre-feed 20 acts as a heat bridge so that the soider and flux flow as is illustrated in Figure 1 to pre-heat the diode bus 34 and the bus bar 30,

[00 33 Figure 3 illustrates a side view of a diode 32 extending between and connected to two opposing bus bars 30. As illustrated, a soider fillet 26 is formed above each bus bar 30 and below each terminai 34, The cathode ierminai 38 extends from the diode 32 substantially parallel to the bus bar 30. The anode terminal 38 when connected with the solder fillet 26 extends slightly upward so that the solder fillet 26 forms a bridge between the anode terminal 38 and the bus bar 30.

[0044] Figure 4 illustrates a photovoltaic module 4 having a plurality of cells 40 and a pair of bus bars 30 extending along the top. The bus bars 30 have a connector 6 at each end. One of the bus bars 30 includes a diode 32.

[0045] Figure 5 illustrates a solar array 4 including a plurality of rows of photovoltaic modules 4 connected together by an integrated flashing pieces 6 at each end.

[0046] Figure 6 illustrates one example of a non-destructive test method that may be used to test the integrity of the solder joints created using the device and method taught herein. The test includes a step 100 of applying a predetermined current across the diode and bus assembly so that voltage passes through the solder fillets formed between the terminals and the bus. While the voltage is being applied across the diode a step 110 of measuring the voltage drop across the diode is performed. The voltage drop is compared to a look up tab!e 120. A step 130 determines if the voltage drop exceed a voltage drop in the look up table, if the voltage drop exceeds the voltage drop of the look up table the soider fillet integrity fails 40, If the voltage is at or beiow the voltage drop of the look up table the soider fiiiet integrity passes 50.

[0047] Figure 7 illustrates an image taken, of a soider fillet 26 as shown in Figure 3_; with a scanning electron microscope with a magnification of 100 times. The solder fiiiet 26 is shown connecting the bus bar 30 to a terminal 34. At a region of the solder fillet 26 proximate to the terminal 34 and the bus bar 30 intermetallic compounds 80 are formed that strengthen the connection,

[0048] Figure 8 illustrates a close-up image of a solder fillet 26 of Figure 7 taken with a scanning electron microscope with a magnification of 5000 times. The solder fillet 26 forms a layer of intermetallic compounds 60 at a region proximate to the bus bar 30. The layer of intermetallic compounds 60 has a thickness of about 3 microns as shown.

[0049] Any numerical values recited herein include all values from the lower value to the upper value in increments of one unit provided that there is a separation of at least 2 units between any lower value and any higher value. As an example, if it is stated that the amount of a component or a value of a process variable such as, for example, temperature, pressure, time and the like is, for example, from 1 to 90, preferably from 20 to 80, more preferably from 30 ίο 70, it is iniended that values such as 15 to 85, 22 to 68, 43 to 51 , 30 to 32 etc. are expressly enumerated in this specification. For values which are less than one, one unit is considered to be 0.0001 , 0.001. 0.01 or 0.1 a appropriate. These are only examples of what is specifically intended and all possible combinations of numerical values between the lowest value and the highest value enumerated are to be considered to be expressiy stated in this application in a similar manner.

[0050] Unless otherwise stated, all ranges include both endpoints and ail numbers between the endpoints. The use of "about" or "approximately" in connection with a range applies to both ends of the range. Thus, "about 20 to 30" is intended to cover "about 20 to about 30", inclusive of at least the specified endpoints.

[00S1J The disclosures of all articles and references, including patent applications and publications, are incorporated by reference for all purposes. The term "consisting essentially of to describe a combination shall include the elements, ingredients, components or steps identified, and such other elements ingredients, components or steps that do not materially affect the basic and novel characteristics of the combination. The use of the terms "comprising" or "including" to describe combinations of elements, ingredients, components or steps herein also contemplates embodiments that consist essentially of the elements, ingredients, components or steps. By use of the term "may" herein, it is intended that any described attributes that "may" be included are optional.

[00S2] Plural elements, ingredients, components or steps can be provided by a single integrated element, ingredient, component or step. Alternatively, a single integrated element, ingredient, component or step might be divided into separate piurai elements, ingredients, components or steps. The disclosure of "a" or "one" to describe an element, ingredient, component or step is not intended to foreclose additional elements, ingredients, components or steps,

[0053] It is understood that the above description is intended to be illustrative and not restrictive, Many embodiments as well as many applications besides the examples provided will be apparent to those of skill in the art upon reading the above description. The scope of the teachings should, therefore, be determined not with reference to the above description, but should instead be determined with reference to the appended claims, along with the full scope of equivalents to which such claims are entitled . The disclosures of all articles and references, including patent applications and publications, are incorporated by reference for a!i purposes. The omission in the following claims of any aspect of subject matter thai is disclosed herein is not a disclaimer of such subject matter, nor should it be regarded that the inventors did not consider such subject matter to be part of the disclosed inventive subject matter.

Claims

We claim:

1 ) A process comprising:

a. aligning one or more terminals of an electrical component ihat has geometry constraints with one or more bus bars of a photovoltaic component;

b. pre-feeding flux and solder fo a tip of a soldering iron; and

c. connecting one or more of the one or more terminals of the electrical component fo one or more busses of the one or more bus bars of the photovoltaic component.

2) The process of claim 1 ₍ wherein the pre-fed flux and solder form a heat bridge between the tip of the solder iron, the one or more bus bars, and the one or more lerminais of the electrical component.

3} The process of claim 2, wherein the tip of the soldering iron is free of direct contact with the one or more terminals of the electrical component, the one or more bus bars of the photovoltaic component, or both.

4) The process of any of claims 2 through 3, wherein the heat bridge is formed for a sufficient duration of time to pre-heal the one or more terminals of the electrical component, the one or more bus bars of photovoltaic component, or both before a second application of flux, solder, or both are applied to form a solde fillet

5} The process of any of claims 2 through 4, wherein the heat bridge transfers thermal energy from the tip of the soldering iron to one of the one or more terminals of the electrical component, one of the one or more bus bars of the photovoltaic component, or both so that the terminal of the electrical component, the bus bar of the photovoltaic component, or both are substantially maintained in position during the step of connecting.

6) The process of any of the preceding claims, wherein the constrained geometry of the electrical component is a geometry where the tip of the soldering iron, solder wire, or both cannot come into contact with the at least one of the one o more terminals of the electrical component, the one or more bus bars of the photovoltaic component, or both proximate to where a connection is created during the step of connecting. 7) The process of any of the preceding ciairrss, wherein the constrained geometry of the eiectricai component is a geometry where heat provided by the solder iron does not transfer to a package the electrical component and damage the electrical component

8) The process of any of the preceding claims, wherein the constrained geometry of the eiectricai component is a geometry where the tip of the soidering iron cannot contact the one or more terminal of the eiectricai component, the one or more bus bars of the photovoltaic component, or both to pre-heat one or more of the terminals of the eiectricai component, the one or more bus bars of the photovoltaic component, or both,

9) The process of any of the preceding claims, wherein the photovoltaic component is iaminaied.

10) The process of any of the preceding claims, wherein the diode is laminated or potted within the photovoltaic component.

1 1 ) The process of any of the preceding claims, wherein a fiiiet of solder is applied between each of the one or more terminals of the photovoltaic component and each of the bus bars of the eiectricai component respectively and the fiilet of solder has a thickness of about 0-050 mm or more.

12) The process of any of the preceding claims, wherein the one or more terminals of the eiectricai component, the one or more bus bars of the photovoltaic component, or both have a sufficient width so that solder is maintained within the width of the bus of the eiectricai component, the bus of the photovoltaic component, or both during the step of connecting.

13) The process of any of the preceding claims, wherein the diode is suspended while the one or more terminals of the eiectricai component and the one or more bus bars of the photovoltaic component are connected.

1 ) The process of any of the preceding claims, wherein the nest is made of ceramic or a metal nest that is heated and includes a coating limit heat transfer from the solder iron, the terminals, the bus bars, or a combination thereof; to resist acids; or both. 15} The process of any of the preceding claims, wherein the fiiiet of solder connecting the one or more terminals of the e!ectricai component to the one or more bus bars of the photovoltaic component is created in 5 seconds or less.

16} The process of any of the preceding claims, wherein a fi!let of soider formed between the one or more terminals of the electrical component and the one or more bus bars of the photovoltaic component during the step of connecting has an interface with a composition that contains a sufficient amount of CueSNe.