Single-toe interconnects

Abstract

The present disclosure relates to single-toe interconnects. Specifically, to an interconnect for establishing an electrical connection for a solar cell, wherein the interconnect consists of a single toe without a second toe connected to the single toe and without a connecting crossbar. Multiple interconnects may be evenly placed across the edge of the solar cell. In one example, when the area of ​​the solar cell is less than 60 cm 2 When the area of ​​the solar cell is greater than 60 cm, three interconnects are evenly placed across the edge of the solar cell. In another example, when the area of ​​the solar cell is greater than 60 cm 2 When four or more interconnects are evenly placed across the edge of the solar cell.

Description

Technical Field

[0001] The present disclosure generally relates to single toe interconnects for solar cells. Background Art

[0002] In order to utilize the electricity generated by solar cells from sunlight, the current must be transferred from the solar cells to external circuits. This is usually done using metal grid lines (fine features that collect current from all areas of the device), one or more busbars (larger features that gather current from many grid lines), contact pads (where tabs / interconnects are attached to connect to other devices), and interconnects with crossovers between contact pads and other devices. These grids, busbars, contact pads, tabs, and interconnects all contribute to parasitic losses.

[0003] Metals used for grids, busbars, contact pads, and interconnects also contribute to power losses related to the conversion efficiency of solar cells by blocking light from reaching the semiconductor layers of the solar cell, through parasitic losses, and through series resistance. For state-of-the-art space solar cells, metal coverage of the solar cell is the dominant loss factor. Optimizing gridline and busbar design is standard practice to reduce obscuration, but the design and location of contacts and interconnects has received less attention.

[0004] Space solar cells typically have two or three interconnects spaced as far apart as possible. This common practice is intended to reduce the risk of an open circuit if the solar cell breaks, but it also results in the current flowing along the busbars over a relatively long distance. Removing the interconnects from large solar cells is known to cause efficiency losses. For example, recent progress has been made for solar cells with an area less than 65 cm 2 For all solar cells, the interconnects are reduced from three to two, with the remaining two interconnects placed as far apart as possible.

[0005] However, widely spaced interconnects increase resistive losses when conducting current to the interconnects and / or result in increased busbar size, thereby reducing battery current. Furthermore, widely spaced interconnects increase the risk that battery cracking may separate all interconnects, thereby creating an open circuit. Additionally, interconnects are provided in multiples of only two leads, resulting in over- or under-designed solutions.

[0006] Therefore, there is a need in the art for improved solar cell interconnects. The present disclosure satisfies that need. Summary of the invention

[0007] To overcome the above limitations, as well as other limitations that will become apparent after reading and understanding this specification, the present disclosure describes an interconnect for establishing electrical connections of solar cells, wherein the interconnect consists of a single toe without a second toe connected to the single toe and without a connected crossbar. The present disclosure also describes a method for manufacturing the interconnect and a method for establishing electrical connections using the interconnect.

[0008] The interconnect is composed of one or more layers of conductive bondable material, wherein the conductive bondable material is selected from aluminum (Al), copper (Cu), silver (Ag), gold (Au), molybdenum (Mo), (FeNi), Invar (64FeNi), or alloys or combinations thereof. The interconnect has a length of about 0.25 inches to 1 inch, a width of 40 mils to 100 mils, and a thickness of 1 mil to 2 mils.

[0009] Multiple interconnects may be placed evenly across the edge of the solar cell. In one example, when the area of ​​the solar cell is less than 60 cm 2 When the area of ​​the solar cell is greater than 60 cm, three interconnects are evenly placed across the edge of the solar cell. In another example, when the area of ​​the solar cell is greater than 60 cm 2 When four or more interconnects are evenly placed across the edge of the solar cell. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Referring now to the drawings, in which like reference numerals designate corresponding parts throughout:

[0011] Figure 1A Shown are typical solar cells and the interconnects used to transmit the power generated by the solar cells.

[0012] Figure 1B A typical configuration of an interconnect is shown.

[0013] Figure 2A An interconnect consisting of a single toe without a second toe and without a crossbar is shown.

[0014] Figure 2B Four interconnects are shown placed along one edge of the solar cell.

[0015] Figure 2C Five interconnects are shown placed along one edge of the solar cell.

[0016] Figure 3 is a graph of the relative power losses (ie, resistive losses, shading, and total power losses) of solar cells with different numbers and types of interconnects.

[0017] Figure 4AMethods of manufacturing solar cells, panels and / or satellites are shown.

[0018] Figure 4B The resulting satellite is shown with panels consisting of solar cells.

[0019] Figure 5 The panel is shown in the form of a functional block diagram. DETAILED DESCRIPTION

[0020] In the following description, reference is made to the accompanying drawings which form a part of this description and in which are shown by way of illustration specific examples in which the present disclosure may be practiced. It should be understood that other examples may be utilized and structural changes may be made without departing from the scope of the present disclosure.

[0021] Overview

[0022] The present disclosure improves the electrical connection between solar cells by replacing relatively fewer, larger interconnects with relatively more, smaller interconnects. Currently, space-level interconnects consist of two parallel, flat metal "toes" or "legs" connected to a crossbar. In the present disclosure, the interconnect consists of a single flat metal toe, without a second toe and without a connected crossbar.

[0023] Utilizing only a single toe to create interconnects allows the number of interconnects (including an odd number of interconnects) to be comparable to the cell and process size. Removing the crossbars allows for more uniform placement of interconnects across the edge of the solar cell, which increases solar cell efficiency, reduces material costs, improves reliability, and enables advanced manufacturing such as real-time laser cutting of interconnects.

[0024] Technical Description

[0025] Figure 1A Shown is a solar cell 10 and an interconnect 12 for transmitting power generated by the solar cell 10. The solar cell 10 includes metal grid lines 14 that collect current from all areas of the solar cell 10, one or more busbars 16 that aggregate the current from the grid lines 14, and contact pads 18 for attaching the interconnect 12 to span between the contact pads 18 and other devices (not shown).

[0026] like Figure 1A As shown, space solar cells 10 typically have two or three interconnects 12 spaced as far apart as possible. This common practice is intended to reduce the risk of an open circuit if the solar cell breaks, but also results in the current flowing a relatively long distance along the busbar 16. However, customers are known to remove the interconnects 12 of large cells 10 (which is known to cause efficiency losses).

[0027] Figure 1B Shown is the configuration of one interconnect 12. The interconnect 12 consists of two thin flat metal toes or legs 20 positioned in parallel with two or more crossbars 22 that hold the two toes 20 in place. Because double toes 20 are used, it is necessary to provide welding redundancy.

[0028] Limitations of this construct include:

[0029] The crossbar 22 requires the double toes 20 to be closely spaced, which is disadvantageous in that mechanical stress is concentrated at the toes 20, and placing the two toes 20 close together increases the stress concentration factor.

[0030] The use of crossbars 22 increases the width of material required to make each interconnect 12 .

[0031] • Farther apart interconnects 12 increase the resistive losses conducting current to the interconnects 12 and / or result in an increase in busbar 16 size, which reduces battery current.

[0032] • Widely spaced interconnects 12 increase the risk that cracking of the solar cell 10 may separate all interconnects 12, thereby causing an open circuit.

[0033] • Interconnects 12 are only provided in multiples of two leads, resulting in over- or under-designed solutions.

[0034] As mentioned above, metal coverage of the solar cell 10 is a major loss factor. The grid lines 14 and busbars 16 have been optimized to reduce shading, but the interconnects 12 have received less attention.

[0035] The present disclosure overcomes these limitations by providing a new design of an improved interconnect having a single toe or leg and distributing the interconnect relatively evenly across the edge of the solar cell.

[0036] Figure 2A , Figure 2B and Figure 2C Devices, methods of manufacture, and methods of establishing electrical connections using this new design are shown, wherein: Figure 2A An interconnect 24 for establishing electrical connection of a solar cell 10 is shown, the interconnect 24 consisting of a single toe 26 without a second toe 20 connected to the single toe 26, and without a connected crossbar 22; Figure 2B A plurality (ie, four) of interconnects 24 are shown evenly spaced along the edge of the solar cell 10; and Figure 2C A plurality (ie, five) of interconnects 24 are shown evenly spaced along the edge of the solar cell 10 .

[0037] In one example, the interconnect 24 is composed of one or more layers of a conductive bondable material (e.g., in the form of a metal foil) selected from aluminum (Al), copper (Cu), silver (Ag), gold (Au), molybdenum (Mo), (FeNi), Invar (64FeNi), or alloys or combinations thereof. The interconnect 24 may be approximately 0.25 to 1 inch in length, 40 to 100 mils in width, and 1 to 2 mils in thickness.

[0038] In one example, when the area of ​​the solar cell 10 is less than 60 cm 2 When the plurality of interconnects includes three interconnects 24 evenly spaced across the edge of the solar cell 10 (i.e., with equal spacing between each interconnect 24). In another example, when the area of ​​the solar cell 10 is greater than 60 cm 2 When the plurality of interconnects 24 includes four or more interconnects 24 evenly placed across the edge of the solar cell 10 .

[0039] The interconnect 24 reduces both current and voltage losses in the busbar 16 while reducing component wear and maintaining risk mitigation for open circuits. Results improve efficiency, reduce parasitic losses, and improve manufacturability by eliminating the double-toed interconnect 12 with connected crossbars 22.

[0040] Figure 3 Is larger than 70cm 2 And a graph of the relative power losses (i.e., resistive losses, shading, and total power losses) of a solar cell 10 having different numbers and types of interconnects (the lower the power losses, the better), wherein the different numbers and types of interconnects include 3 double-toed interconnects (ICs) 12, 4 single-toed ICs 24, 5 single-toed ICs 24, 6 single-toed ICs 24, and 8 20-mil wire bonds.

[0041] From an operational efficiency perspective, there are reasons why one might not favor this solution of a single-toed interconnect 24. For example, the reduced metal used for the interconnect 24 may increase the likelihood of damage.

[0042] However, using single-toed interconnects 24 between solar cells 10 provides numerous benefits including increased redundancy, reduced component wear, more flexible design options, increased reliability, improved efficiency, reduced material costs, and advanced manufacturing.

[0043] For example, the number of interconnections can be increased using single-toe interconnects 24 to increase redundancy. Alternatively, the number of interconnections using single-toe interconnects 24 can be reduced to reduce component wear.

[0044] The present disclosure provides more flexible design options because by using the new interconnect 24, the solar cell 10 can have more interconnection points (more redundancy) or fewer interconnection points (reduced component wear).

[0045] Specifically, by removing the crossbar 22 between the double toes 20, the present disclosure provides more design freedom to select the number of interconnections and the location of those interconnections using the new interconnect 24. For example, by using the interconnect 24, an odd number of interconnections of the solar cells 10 is possible, while the interconnect 12 always results in an even number of interconnections due to the double toes 20.

[0046] The present disclosure may provide equal, greater, or lesser reliability than currently required, as determined by the number, spacing, and / or location of interconnects 24. For example, the number, spacing, and location (either evenly spaced or positioned based on some other constraints) of interconnects may be selected to improve the efficiency of solar cells 10. Specifically, the location of interconnects using interconnects 24 is not constrained by crossbars 22.

[0047] Removing the crossbars 22 allows for more uniform placement of the interconnects 24 across the edges of the solar cell 10, which simultaneously improves the efficiency of the solar cell 10, reduces material costs, and improves reliability. For example, uniform spacing of the interconnects 24 results in improved reliability by reducing the likelihood that cracking of the solar cell 10 may electrically separate the interconnects 24, thereby creating an open circuit. Uniform spacing of the interconnects 24 also results in higher efficiency of the solar cell 10 due to reduced shading and resistive losses of the busbar 16.

[0048] The single-toed interconnect 24 inherently reduces the amount of material consumed in manufacturing and therefore reduces the cost of the interconnect 24. The crossbar 22 increases the material consumption and cost of the interconnect 12 and increases the shadowing of the contact pads 18 on the solar cell 10. The single-toed interconnect 24 is more compatible with advanced manufacturing concepts such as real-time laser cutting of the interconnect 24 from raw stock material. The single-toed interconnect 24 also provides mechanical stress relief for the solar cell 10.

[0049] manufacture

[0050] The method 28 (e.g., manufacturing one or more interconnects 24, a solar cell 10 using the interconnect 24, a panel composed of the solar cell 10, and / or a space vehicle such as a satellite including the panel) may be described. Figure 4A As shown, the method 28 includes steps 30 to 42) in the context of describing an example of the present disclosure, wherein, Figure 4BThe resulting satellite 44 is shown, consisting of various systems 46 and a body 48 , including a panel 50 consisting of an array 52 of one or more solar cells 10 .

[0051] like Figure 4A As shown, during pre-production, an exemplary method 28 may include specification and design 30 of a satellite 44 and procurement of materials 32 for the satellite. During production, component and subassembly manufacturing 34 and system integration 36 of the satellite 44 are performed, which includes manufacturing the satellite 44, panels 50, arrays 52, and solar cells 10. Thereafter, the satellite 44 may be certified and delivered 38 for entry into service 40. Prior to launch, maintenance and service 42 (including modification, reconstruction, refurbishment, etc.) of the satellite 44 may also be scheduled.

[0052] Each of the processes of method 28 may be performed or implemented by a system integrator, a third party, and / or an operator (e.g., a customer). For the purposes of this description, a system integrator may include, but is not limited to, any number of manufacturers and major system contractors; a third party may include, but is not limited to, any number of vendors, contractors, and suppliers; and an operator may be a satellite company, a military entity, a service organization, etc.

[0053] like Figure 4B As shown, a satellite 44 manufactured by exemplary method 28 may include various systems 46 and a body 48. Examples of systems 46 included in satellite 44 include, but are not limited to, one or more of a propulsion system 54, an electrical system 56, a communication system 58, and a power system 60. Any number of other systems may also be included.

[0054] Functional Block Diagram

[0055] Figure 5 A panel 50 according to one example is shown in functional block diagram form. The panel 50 is comprised of an array 52 of one or more of the solar cells 10 individually attached to the panel 50. Each of the solar cells 10 absorbs light 62 from a light source 64 and generates an electrical output 66 in response thereto.

[0056] At least one of the solar cells 10 includes at least: metal grid lines 14, which collect current from all areas of the solar cell 10; busbars 16, which gather current from the grid lines 14; and contact pads 18, which are used to attach interconnects 24 to bridge between the contact pads 18 and other devices (not shown) to establish electrical connections.

[0057] In addition, this disclosure includes examples according to the following clauses:

[0058] Clause 1. A device comprising: one or more interconnects for establishing an electrical connection, each of the interconnects consisting of a single toe without a second toe connected to the single toe and without a connected crossbar.

[0059] Clause 2. The device of clause 1, wherein each of the interconnects is composed of one or more layers of a conductive bondable material selected from the group consisting of aluminum (Al), copper (Cu), silver (Ag), gold (Au), molybdenum (Mo), (iron-nickel-cobalt alloy), Invar (64FeNi), or alloys or combinations thereof.

[0060] Clause 3. The apparatus of clause 1 or 2, wherein each of the interconnects has a length of approximately 0.25 inches to 1 inch, a width of 40 mils to 100 mils, and a thickness of 1 mil to 2 mils.

[0061] Clause 4. The apparatus of any one of clauses 1 to 3, wherein the interconnect establishes the electrical connection of a solar cell.

[0062] Clause 5. The apparatus of clause 4, wherein the plurality of interconnects are evenly placed across an edge of the solar cell.

[0063] Clause 6. The apparatus of clause 5, wherein the plurality of interconnects comprises three interconnects evenly spaced across an edge of the solar cell, and the area of ​​the solar cell is less than 60 cm 2 .

[0064] Clause 7. The apparatus of clause 5, wherein the plurality of interconnects comprises four or more interconnects evenly spaced across an edge of the solar cell, and the area of ​​the solar cell is greater than 60 cm 2 .

[0065] Clause 8. A method comprising the steps of: manufacturing one or more interconnects for establishing an electrical connection, each of the interconnects consisting of a single toe without a second toe connected to the single toe and without a connected crossbar.

[0066] Clause 9. The method according to clause 8, wherein each of the interconnects is composed of one or more layers of a conductive bondable material selected from the group consisting of aluminum (Al), copper (Cu), silver (Ag), gold (Au), molybdenum (Mo), (iron-nickel-cobalt alloy), Invar (64FeNi), or alloys or combinations thereof.

[0067] Clause 10. The method of clause 8 or 9, wherein each of the interconnects has a length of approximately 0.25 inches to 1 inch, a width of 40 mils to 100 mils, and a thickness of 1 mil to 2 mils.

[0068] Clause 11. The method of any one of clauses 8 to 10, wherein the interconnect establishes the electrical connection of a solar cell.

[0069] Clause 12. The method of clause 11, wherein the plurality of interconnects are evenly placed across an edge of the solar cell.

[0070] Clause 13. The method of clause 12, wherein the plurality of interconnects comprises three interconnects evenly spaced across an edge of the solar cell, and the area of ​​the solar cell is less than 60 cm 2 .

[0071] Clause 14. The method of clause 12, wherein the plurality of interconnects comprises four or more interconnects evenly spaced across an edge of the solar cell, and the area of ​​the solar cell is greater than 60 cm 2

[0072] Clause 15. A method comprising the steps of establishing an electrical connection to one or more solar cells using one or more interconnects, each of the interconnects consisting of a single toe without a second toe connected to the single toe and without a connected crossbar.

[0073] Clause 16. The method of Clause 15, further comprising the step of establishing the electrical connection with the one or more solar cells in a panel comprised of an array of the one or more solar cells.

[0074] Clause 17. The method of Clause 16, further comprising the step of establishing an electrical connection with the one or more solar cells in a space vehicle that includes the panel.

[0075] Clause 18. A device comprising: one or more solar cells; and one or more interconnects for establishing electrical connections with the solar cells, each of the interconnects consisting of a single toe without a second toe connected to the single toe and without a connected crossbar.

[0076] Clause 19. The apparatus of clause 18, wherein the one or more interconnects comprise a cross-sectional area less than 60 cm 2 The solar cells have three interconnecting members evenly placed on the edge of one solar cell.

[0077] Clause 20. The apparatus of clause 18 or 19, wherein the one or more interconnects comprise a cross-sectional area greater than 60 cm 2 Four or more interconnecting members are evenly placed on the edge of one of the solar cells.

[0078] Clause 21. The apparatus of any of Clauses 18 to 20, further comprising a panel comprised of an array of said solar cells.

[0079] Clause 22. The apparatus of clause 21, further comprising a space carrier having the panel.

Claims

1. A device, comprising: A plurality of interconnects (24) for establishing electrical connections only between solar cells, at least one of the solar cells comprising one or more metal grid lines for collecting current, one or more busbars for collecting current from the grid lines, and one or more contact pads for electrically connecting the interconnects (24) to the busbars, Each of the interconnects (24) is composed of a single metal toe (26), the single metal toe (26) is composed of a metal foil that remains flat when transmitting electrical energy generated by the solar cell, and each of the interconnects (24) is electrically connected to a single one of the contact pads and is separated from other interconnects so as to bridge between the single one of the contact pads and other solar cells, each of the interconnects (24) is not connected to a second metal toe (20) of the single metal toe (26), and has no connected crossbar (22), Wherein, when the area of ​​at least one of the solar cells is greater than 60 cm 2 When the interconnects are arranged in a uniform manner across one edge of the at least one solar cell in the solar cells, four or more of the interconnects are evenly spaced with equal spacing between the interconnects, or When the area of ​​at least one of the solar cells is less than 60 cm 2 When the interconnects are arranged evenly across one edge of the at least one solar cell in the solar cells, the spacings between the interconnects are equal, Each of the interconnects (24) has a length of approximately 0.25 inches to 1 inch, a width of 40 mils to 100 mils, and a thickness of 1 mil to 2 mils.

2. The device according to claim 1, wherein: Each of the interconnects (24) is composed of one or more layers of conductive bondable material, wherein the conductive bondable material is selected from aluminum Al, copper Cu, silver Ag, gold Au, molybdenum Mo, iron nickel cobalt alloy, Invar 64FeNi, or alloys or combinations thereof.

3. A method comprising the following steps: manufacturing a plurality of interconnects (24) for establishing electrical connections only between solar cells, at least one of the solar cells comprising one or more metal grid lines for collecting current, one or more busbars for collecting current from the grid lines, and one or more contact pads for electrically connecting the interconnects (24) to the busbars, Each of the interconnects (24) is composed of a single metal toe (26), the single metal toe (26) is composed of a metal foil that remains flat when transmitting electrical energy generated by the solar cell, and each of the interconnects (24) is electrically connected to a single one of the contact pads and is separated from other interconnects so as to bridge between the single one of the contact pads and other solar cells, each of the interconnects (24) is not connected to a second metal toe (20) of the single metal toe (26), and has no connected crossbar (22), Wherein, when the area of ​​at least one of the solar cells is greater than 60 cm 2 When the interconnects are arranged in a uniform manner across one edge of the at least one solar cell in the solar cells, four or more of the interconnects are evenly spaced with equal spacing between the interconnects, or When the area of ​​at least one of the solar cells is less than 60 cm 2 When the interconnects are arranged evenly across one edge of the at least one solar cell in the solar cells, the spacings between the interconnects are equal, Each of the interconnects (24) has a length of approximately 0.25 inches to 1 inch, a width of 40 mils to 100 mils, and a thickness of 1 mil to 2 mils.

4. The method according to claim 3, wherein: Each of the interconnects (24) is composed of one or more layers of conductive bondable material, wherein the conductive bondable material is selected from aluminum Al, copper Cu, silver Ag, gold Au, molybdenum Mo, iron nickel cobalt alloy, Invar 64FeNi, or alloys or combinations thereof.

5. A method comprising the following steps: A plurality of interconnects (24) are used to establish electrical connections only between solar cells (10), at least one of the solar cells comprising one or more metal grid lines for collecting current, one or more busbars for collecting current from the grid lines, and one or more contact pads for electrically connecting the interconnects (24) to the busbars, Each of the interconnects (24) is composed of a single metal toe (26), the single metal toe (26) is composed of a metal foil that remains flat when transmitting electrical energy generated by the solar cell, and each of the interconnects (24) is electrically connected to a single one of the contact pads and is separated from other interconnects so as to bridge between the single one of the contact pads and other solar cells, each of the interconnects (24) is not connected to a second metal toe (20) of the single metal toe (26), and has no connected crossbar (22), Wherein, when the area of ​​at least one of the solar cells is greater than 60 cm 2 When the interconnects are arranged in a uniform manner across one edge of the at least one solar cell in the solar cells, four or more of the interconnects are evenly spaced with equal spacing between the interconnects, or When the area of ​​at least one of the solar cells is less than 60 cm 2 When the interconnects are arranged evenly across one edge of the at least one solar cell in the solar cells, the spacings between the interconnects are equal, Each of the interconnects (24) has a length of approximately 0.25 inches to 1 inch, a width of 40 mils to 100 mils, and a thickness of 1 mil to 2 mils.

6. The method according to claim 5, further comprising the steps of: Electrical connections are established with the solar cells (10) in a panel (50) comprised of an array (52) of the solar cells (10).

7. The method according to claim 6, further comprising the steps of: An electrical connection is established with the solar cell (10) in a space vehicle including the panel (50).

8. A device, comprising: one or more solar cells (10); as well as A plurality of interconnects (24) for establishing electrical connections only with the solar cells (10), at least one of the solar cells comprising one or more metal grid lines for collecting current, one or more busbars for collecting current from the grid lines, and one or more contact pads for electrically connecting the interconnects (24) to the busbars, Each of the interconnects (24) is composed of a single metal toe (26), the single metal toe (26) is composed of a metal foil that remains flat when transmitting electrical energy generated by the solar cell, and each of the interconnects (24) is electrically connected to a single one of the contact pads and is separated from other interconnects so as to bridge between the single one of the contact pads and other solar cells, each of the interconnects (24) is not connected to a second metal toe (20) of the single metal toe (26), and has no connected crossbar (22), Wherein, when the area of ​​at least one of the solar cells is greater than 60 cm 2 When the interconnects are arranged in a uniform manner across one edge of the at least one solar cell in the solar cells, four or more of the interconnects are evenly spaced with equal spacing between the interconnects, or When the area of ​​at least one of the solar cells is less than 60 cm 2 When the interconnects are arranged evenly across one edge of the at least one solar cell in the solar cells, the spacings between the interconnects are equal, Each of the interconnects (24) has a length of approximately 0.25 inches to 1 inch, a width of 40 mils to 100 mils, and a thickness of 1 mil to 2 mils.

9. The device according to claim 8, further comprising a panel (50) consisting of an array (52) of said solar cells (10).

10. The device according to claim 9, further comprising a space carrier having the panel (50).

11. The device according to claim 8, wherein: Each of the interconnects (24) is composed of one or more layers of conductive bondable material, wherein the conductive bondable material is selected from aluminum Al, copper Cu, silver Ag, gold Au, molybdenum Mo, iron nickel cobalt alloy, Invar 64FeNi, or alloys or combinations thereof.

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