AN ELECTRODE ASSEMBLY

Abstract

An electrode assembly for connecting a front surface of a first solar cell to a back surface of a second solar cell, the electrode assembly comprising: a plurality of conductive elements, wherein at least one of the conductive elements comprises: a first surface for contacting the front surface of the first solar cell; and a second surface for contacting the back surface of the second solar cell, the second surface being arranged opposite the first surface; wherein at least a portion of each of the first and second surfaces comprises a coating for connecting the respective surfaces of the at least one conductive element to a surface of the solar cell; wherein the second surface is configured to define a contact area which is substantially smaller than the contact area defined by the first surface.

Claims

1. An electrode assembly for connecting a front surface of a first solar cell to a back surface of a second solar cell, the electrode assembly comprising: a plurality of conductive elements, wherein at least one of the conductive elements comprises: a first surface for contacting the front surface of the first solar cell; and a second surface for contacting the back surface of the second solar cell, the second surface being arranged opposite the first surface; wherein at least a portion of each of the first and second surfaces comprises a coating for connecting the respective surfaces of the at least one conductive element to a surface of the solar cell; wherein the second surface is configured to define a contact area which is substantially smaller than the contact area defined by the first surface.

2. The electrode assembly according to claim 1, wherein the second surface is substantially curved.

3. The electrode assembly according to claim 2, wherein the second surface curves outwardly from the conductive element.

4. The electrode assembly according to claim 3, wherein the at least one conductive element comprises a cross section shaped as an elliptical segment.

5. The electrode assembly according to claim 1, wherein the second surface is substantially flat.

6. The electrode assembly according to claim 1, wherein the first surface is substantially flat.

7. The electrode assembly according to claim 6, wherein the first surface is substantially parallel to the second surface.

8. The electrode assembly according to claim 1, wherein the at least one conductive element comprises a third surface arranged between the first and second surfaces, the third surface being configured to space apart the first surface from the second surface.

9. The electrode assembly according to claim 8, wherein the third surface is substantially flat.

10. The electrode assembly according to claim 8, wherein the third surface is substantially curved.

11. The electrode assembly according to claim 10, wherein the third surface curves outwardly from the conductive element.

12. The electrode assembly according to claim 1, wherein the coating is configured to substantially cover the first and second surfaces.

13. The electrode assembly according to claim 12, wherein the coating is configured to substantially cover each of the conductive element's surfaces.

14. The electrode assembly according to claim 1, wherein at least a portion of the conductive elements are arranged in or on an insulating and optically transparent film, wherein at least a portion of at least one of the first and second surfaces of the at least one conductive element is exposed from the film to form an ohmic contact with the respective front and back surfaces of the first and second solar cells.

15. A solar cell assembly comprising a first solar cell, a second solar cell and an electrode assembly according to claim 1, wherein the plurality of conductive elements are configured to electrically couple a front surface of the first solar cell with a back surface of the second solar cell.

16. A method of manufacturing a solar cell assembly according to claim 15, the method comprising: arranging the second solar cell so that its back surface faces in a substantially upward direction; overlaying a first section of the electrode assembly onto the back surface of the second solar cell such that the second surface of the at least one conductive element is arranged in contact with the back surface; connecting the second surface of the at least one conductive element onto the back surface of the second solar cell; overlaying the front surface of the first solar cell onto a second section of the electrode assembly such that the first surface of the at least one conductive element is arranged in contact with the front surface; and connecting the first surface of the at least one conductive element onto the front surface of the first solar cell.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0087] Embodiments will now be described by way of example only, with reference to the Figures, in which:

[0088] FIG. 1 is a close-up sectional side view of a solar module including a solar cell assembly, the solar cell assembly comprising a first solar cell coupled to a second solar cell by an electrode assembly;

[0089] FIGS. 2A and 2C are plan views of the top (front) and bottom (back) of the first and second solar cells, respectively, as shown in FIG. 1, respectively;

[0090] FIGS. 2B and 2D are transverse sectional views taken through the first and second solar cells, respectively, as shown in FIGS. 2A and 2C;

[0091] FIGS. 3A and 3B are close-up sectional views of the first and second solar cells shown in FIGS. 2A to 2D;

[0092] FIGS. 4 to 9 are sectional views of alternative conductive elements suitable for use in the electrode assembly shown in FIG. 1;

[0093] FIGS. 10A to 15A are side views of a solar cell assembly, showing the different stages of a method of manufacturing the assembly;

[0094] FIGS. 10B to 15B are sectional views of the solar cells of the solar cell assembly shown in FIGS. 10A to 15A, showing the different stages of the manufacturing method; and

[0095] FIG. 16 is a flowchart illustrating a method of manufacturing the solar cell assembly, as shown in FIGS. 15A and 15B.

DETAILED DESCRIPTION

[0096] Aspects and embodiments of the present disclosure will now be discussed with reference to the accompanying figures. Further aspects and embodiments will be apparent to those skilled in the art.

[0097] In the drawings, the thickness of layers, films, elements etc., are exaggerated for clarity. Furthermore, it will be understood that when an element such as a layer, film, region, or substrate is referred to as being on another element, it can be directly on the other element or intervening elements may also be present. In contrast, when an element is referred to as being directly on another element, there are no intervening elements present.

[0098] FIG. 1 shows a solar cell assembly 10 according to the present invention, which is arranged within a support assembly 102 of a solar module 100 (e.g. a solar panel). The solar cell assembly 10 includes a first solar cell 20, a second solar cell 30 and an electrode assembly 12 which is arranged to electrically couple a front surface 22 of the first solar cell 20 to a back surface 34 of the second solar cell 30.

[0099] The electrode assembly 12 comprises a plurality of conductive elements which are configured to provide an improved electrical pathway between the first and second solar cells 20, 30, whilst also enhancing the light scattering and absorption conditions at the front surface 22 of the first solar cell 20.

[0100] A first portion of the electrode assembly 12 is arranged to contact the front surface 22 of the first solar cell 20 to define a front connecting portion, or front connector 12a, of the electrode assembly 12. A second portion of the electrode assembly 12 contacts the back surface 34 of the second solar cell 30 to define a back connecting portion, or back connector 12b, of the electrode assembly 12. The first and second connectors 12a, 12b are electrically coupled together by a third interconnecting portion 12c which bends between the respective upper and lower surfaces 22, 34 of the adjacently positioned solar cells 20, 30 of the solar cell assembly 10.

[0101] The solar cell assembly 10 is one of a plurality of solar cell assemblies which are arranged within the support assembly 102. For example, a front surface 32 of the second solar cell 30 is electrically coupled to the back surface of a third solar cell (not shown) by a second electrode assembly 14. Also, a third electrode assembly 16 is provided to couple a back surface 24 of the first solar cell 20 to the front surface of a fourth solar cell (not shown).

[0102] It will be understood, for example, that the second and third solar cells in this arrangement are electrically coupled together by the second electrode assembly 14 to define a second solar cell assembly. The plurality of solar cells 20, 30 are thereby coupled together by the electrode assemblies 12, 14, 16 to define a single string.

[0103] A front plate 104 of the support assembly 102 comprises a transparent (e.g. glass) sheet which is configured to allow light to pass through into a central chamber 106 in which the solar cell assembly 10 is mounted. The arrows at the top of FIG. 1 show the direction of the solar radiation which is incident upon the solar cell assembly 10.

[0104] A back plate 108 of the support assembly 102 is arranged to enclose the solar cell assembly 10 within the central chamber 106. The back plate 108 comprises a reflective sheet which is configured to reflect any light which is incident upon its upper surface, back towards the solar cell assembly 10. The central chamber 106 is filled with an encapsulating material (the shaded area shown in FIG. 1) which prevents ingress of external liquid or gaseous entrants.

[0105] FIGS. 2A and 2C illustrate the top (front) and bottom (back) view of the first and second solar cells 20, 30, respectively, of the solar cell assembly 10. FIGS. 2B and 2D show transverse sectional views of the first and second solar cells 20, 30, respectively, taken along the dashed lines A-A and B-B, as shown in FIGS. 2A and 2C.

[0106] Each of the solar cells 20, 30 has a length which is the vertical dimension of FIGS. 2A and 2C, and a width which is the horizontal dimension of FIGS. 2A and 2C. The first and second solar cells 20, 30 are arranged in a common transverse plane (as shown in FIG. 1) such that their width wise and lengthwise dimensions lie in parallel with each other. Each of the front surfaces 22, 32 of the respective solar cells define a surface on which light is incident when the solar cell assembly 10 is in use. The back surfaces 24, 34 each define a surface which is opposite to the respective front surface 22, 32, as shown in FIGS. 2B, 2D.

[0107] Each solar cell 20, 30 includes a layered structure (not shown) arranged between its respective front and back surfaces. The layered structure is a multi-layer semiconductor assembly which includes a photovoltaic element (or layer) which is configured to generate electrical charge carriers from the absorption of incident radiation. The front and back finger electrodes 26, 36, 28, 38 are each configured to conduct away the electrical charge carriers generated by the respective solar cell 20, 30.

[0108] The first solar cell 20 includes a first plurality of finger electrodes 26 arranged on its front surface 22 (i.e. front finger electrodes), and a second plurality of finger electrodes 28 arranged on its back surface 24 (i.e. back finger electrodes). Similar, the second solar cell 30 includes a first plurality of finger electrodes 36 arranged on its front surface 32, and a second plurality of finger electrodes 38 arranged on its back surface 34.

[0109] The electrode assembly 12 comprises a plurality of conductive elements 18, as shown in FIGS. 2A to 2D. The conductive elements are configured to form an ohmic contact with finger electrodes 26, 38 arranged on the front and back surfaces 22, 34 of the first and second solar cells, respectively. The conductive elements 18 each have an integral elongate form, such as a wire, which is formed of an electrically conductive material. For example, the conductive elements 18 are comprise a metallic alloy material, which includes at least one of Ag, Al, Au and Cu. The conductive elements 18 are each arranged within an optically transparent insulating film 40, as shown most clearly in FIGS. 2B and 2D.

[0110] A first portion 18a of the plurality of conductive elements 18 defines the front connector 12a of the electrode assembly 12. A second portion 18b of the plurality of conductive elements 18 defines the back connector 12b of the electrode assembly 12. Accordingly, each of the plurality of conductive elements 18 extends from the front connector 12a to the back connector 12b of the electrode assembly 12. A third portion 18c of the plurality of conductive elements 18 is configured to electrically couple together the respective first and second portions 12a, 12b.

[0111] The conductive elements 18 are configured, in the third portion 18a, to bend along an axial direction of the conductive element 18 so as to allow the electrode assembly 12 to form an electrical connection between the front and back connectors 12a, 12b.

[0112] As described above, the conductive elements 32 are formed of an electrically conductive material such that they are configured to allow electrical charge carriers to flow between the conductive elements 18 and the finger electrodes 26, 38 on the front and back surfaces 22, 34 of the first and second solar cells 20, 30. In this way, each of the conductive elements 18 defines a current collector of the electrode assembly 12. Furthermore, the conductive elements 18 are configured to collect charge carriers from the front finger electrodes 26 of the first solar cell 20 and transport them to the back-finger electrodes 38 of the second solar cell 30, or vice versa.

[0113] Each of the conductive elements 18 comprises a width, length, and depth. The length of each conductive elements 18 defines an axial length which is substantially greater than its width and depth. The conductive elements 18 are configured with an asymmetrical cross-section, which leads to an improved electrical connection between the conductive elements 18 and the finger electrodes 26, 38 on the surfaces of the solar cells, as will be explained in more detail below.

[0114] With reference to FIGS. 2A to 2D, the arrangement of each of the pluralities of finger electrodes 26, 28, 36, 38 and conductive elements 18 will now be described in more detail.

[0115] The pluralities of front and back finger electrodes 26, 28, 36, 38 are arranged to extend across the solar cells 20, 30 in the transverse direction (the horizontal direction in FIGS. 2A, 2C) and are equally spaced apart in the longitudinal direction (the vertical direction in FIGS. 2A, 2C).

[0116] The dimensions of each finger electrode 26, 28, 36, 38 are substantially the same as that of every other finger electrode 26, 28, 36, 38. For example, the finger electrodes have a common length, width and depth such that each electrode is arranged to protrude from the surface of the solar cell by the same amount. Furthermore, each of the finger electrodes has a rectangular cross-section (which is measured perpendicular to the electrode's length).

[0117] The finger electrodes arranged on each of the front and back surfaces 26, 28, 36, 38 of the solar cells 20, 30 are aligned in parallel with each other, and with a corresponding finger electrode on the opposite side of the solar cell. For example, each one of the finger electrodes 26 arranged on the front surface 22 of the first solar cell 20 is longitudinally aligned with a corresponding finger electrode 28 from the plurality of back finger electrodes 28. As shown in FIGS. 2A and 2C, each of the pluralities of front and back finger electrodes 26, 28, 36, 38 comprises twelve electrodes. However, it is to be understood that in some other embodiments, the number of front and back finger electrodes 26, 28, 36, 38 may be different, without departing from the scope of the present invention.

[0118] The number of conductive elements 18 of the electrode assembly 12 is between 4 and 20. According to the embodiment described herein the first electrode assembly 12 has between fourteen and eighteen conductive elements 18, for example sixteen conductive elements 18 as shown in FIGS. 2A to 2D. However, it will be appreciated that, in some other embodiments, a different number of conductive elements may be present, without departing from the scope of the present invention.

[0119] The first and second portions 18a, 18b of the plurality of conductive elements 18 are parallel and extend lengthwise relative to the front and back surfaces 22, 34 of the solar cells, in a longitudinal direction (the vertical direction in FIG. 2A). The conductive elements 18 are also equally spaced apart in a transverse direction relative to the front and back surfaces 22, 34 (the horizontal direction in FIG. 2A) to define longitudinal-extending spaces between the conductive elements 18. Accordingly, each one of the first and second portions 18a, 18b defines an array of parallel, transversely spaced conductive elements 18.

[0120] Each of the first portions 18a of the plurality of conductive elements 18 are axially aligned with the corresponding second portions 18b of the conductive elements 18 of the same electrode assembly 12. Also, the second portions 18b of conductive elements 18 of the first electrode assembly 12 are axially aligned with the first portions 18a of the conductive elements 18 of the second electrode assembly 14, with the second solar cell 30 interposed between.

[0121] According to the above described arrangement, it will be understood that the pluralities of front and back finger electrodes 26, 38 are arranged perpendicular to the first and second portions 18a, 18b of the plurality of conductive elements 18, as shown in FIGS. 2A and 2C.

[0122] The finger electrodes 26, 28, 36, 38 are formed of an electrically conductive material, which is formed of a metallic alloy comprising Ag. The electrically conductive material is a printed material, which enables the finger electrodes to be conveniently deposited onto the respective surfaces of the solar cells. The printed material is formed using a printable precursor, such as a conductive paste, which comprises a mixture of silver metal powder and glass frit suspended in a solvent. The conductive paste may be fired, or cured, to form the finger electrodes.

[0123] As described above, the electrode assembly 12 comprises an insulating and optically transparent film 40 in which the conductive elements 18 are arranged. The first and second portions 18a, 18b of the plurality of conductive elements 18 are each arranged in separate film portions, which are arranged on the front and back surfaces 22, 34 of the respective solar cells. For example, the front connector 12a comprises a first film portion which defines a front film portion 42 and the back connector 12b comprises a second film portion which defines a back-film portion 44. However, it is noted that the conductive elements 18 in the third portion 18c are free from any film covering.

[0124] According to an exemplary arrangement of the solar cell assembly 10, each of the first and second portions 18a, 18b of the conductive elements 18 is attached to a surface of its respective film 42, 44 that faces the solar cell. This solar cell-facing surface of each film 42, 44 is coated with an adhesive which adheres the conductive elements to their respective films 42, 44.

[0125] With reference to FIGS. 2B and 2D, in the case of the front connector 12a, the film 42 is arranged to contact the front surface 22 of the solar cell in the areas in-between the conductive elements 18 and the front finger electrodes 26. The back-film portion 44 is configured in the same way for the back connector 12b.

[0126] In an exemplary arrangement of the solar cell assembly 10 each of the films 42, 44 is configured to at least partially (e.g. completely) envelope, or surround, the respective conductive elements 18 and the respective finger electrodes 26, 38, as shown in FIGS. 2B and 2D.

[0127] The front and back film portions 42, 44 are arranged to provide adhesion between the solar cells and the conductive elements 18 so that the conductive elements are correctly arranged on the solar cells (i.e. aligned with the finger electrodes). In an exemplary embodiment, the front and back film portions 42, 44 may not fully cover the respective surfaces of the solar cells.

[0128] Whilst the front and back film portions 42, 44 shown in the drawings comprise substantially planar bottom and top surfaces, respectively. It will be understood that the films may be configured to conform to the structural components of solar cells and/or conductive elements. For example, the film 40 of the back connector 12b may conform to the finger electrodes 38 and conductive elements 18 which are arranged on the back surface 34 of the solar cell 30. According to this exemplary arrangement, the film 40 may be comprised of elongate channels recessed towards the solar cell in the regions of the back surface 34 in-between conductive elements, and may form ridges/protuberances over the structures electrodes (e.g. finger electrodes and conductive elements) where they are present.

[0129] The front and back film portions 42, 44 are applied with heat and pressure onto the respective surfaces of the solar cells so that the films will conform to the finger electrodes and conductive elements arranged thereon.

[0130] According to an alternative exemplary arrangement, the films 40 may comprise channels, arranged on their respective solar cell facing surfaces. The channels may be configured to provide a tight fit around the corresponding conductive elements and finger electrodes.

[0131] The front and back film portions 42, 44 may be thinner than the conductive elements 18. For example, the conductive elements 18 may have a thickness (i.e., depth) of at least 200 m and up to 400 m (e.g., between 0.2 mm and 0.4 mm), whereas the films have a thickness of at least 70 m and up to 120 m (e.g., between 0.07 mm and 0.12 mm).

[0132] The front and back film portions 42, 44 are each formed of a polymer material having a high ductility, good insulating characteristics, optical transparency and thermal stability, resistance to shrinkage. An exemplary polymer material is comprised of modified ethylene tetrafluoroethylene.

[0133] With reference to FIGS. 3A, 3B and 4 to 9, the configuration of the conductive elements 18 will now be described in more detail. In an exemplary arrangement, the conductive elements 18 each have a semi-circular transverse cross-sectional shape (i.e. transverse to the axial length of the conductive element 18), as shown in FIGS. 3A, 3B, 4 and 7. However, the conductive elements 18 may be configured with different cross-sectional shapes, as shown in FIGS. 5, 6, 8 and 9, without departing from the scope of the present invention.

[0134] Each of the conductive elements 18 comprises a first surface 50 which is configured to electrically contact the front surface 22 of the first solar cell 20, as shown in FIG. 3A. Each conductive element 18 also comprises a second surface 54 configured to electrically contact the back surface 34 of the second solar cell 30, as shown in FIG. 3B.

[0135] At least a portion of each of the first and second surfaces 50, 52 comprises a coating 60 which is configured, when in use, to solder the respective first and second surfaces 50, 52 to a surface of the solar cells 20, 30 upon which they are overlaid.

[0136] It will be appreciated that FIG. 3A shows the first portion 18a of the conductive elements 18 on the front surface 22 of the first solar cell 20 (i.e. the front connector 12a of the electrode assembly 12), whereas FIG. 3B illustrates the second portion 18b of the same conductive elements 18 on the back surface 34 of the second solar cell 30 (i.e. the back connector 12b of the electrode assembly 12).

[0137] The first and second surfaces 50, 52 define two distinct longitudinal surfaces of the conductive element 18 (i.e. the surfaces which extend in a longitudinal direction of the conductive element). In particular, the first and second surfaces 50, 52 define upper or lower surfaces of the conductive element 18. As such, the first surface 50 is arranged on the opposite side of the conductive element 18 from the second surface 52.

[0138] The conductive elements 18 each comprise a first surface 50 which is substantially flat. The first surface 50 of the conductive element portion 18a is configured with a planar surface which faces, and lies parallel to, the front surface 22 of the first solar cell 20, as shown in FIG. 3A. The flat first surface 50 is particularly advantageous in situations where the solar cells are inverted during their connection to the electrode assembly 12. In such situations, the first surface 50 of the conductive elements 18 are arranged to face in a substantially upward direction (e.g. vertically up), as will be described in more detail below. When heat and/or pressure is applied to the conductive elements 18 (e.g. lamination) to form the connection with the front solar cell surface 22, the coating 60 is supported on the flat surface and thereby prevented from flowing, due to gravity, away from the contact interface with the solar cell surface.

[0139] In contrast to the first surface 50, the conductive elements' second surfaces 52 are substantially curved, as shown in FIG. 3B. The convex shape of the second surface 52 defines a cross-sectional arc whose ends terminate at the edges of the first surface 50. In this way, the conductive elements 18 each comprise a semi-elliptical cross section, as shown in FIGS. 3A and 3B.

[0140] The contact area of the first surface 50 is defined by a width of the first surface 50 which forms the electrical contact with the front surface 22 of the first solar cell 20 (e.g. the front finger electrode 36). Accordingly, the contact area of the first surface 50 is substantially defined by the width of the coating 60 which forms between the first surface 50 and the front surface 22 of the solar cell, as shown by the in FIG. 3A.

[0141] The contact area of the second surface 52 is defined by a width of the second surface 52 which forms an electrical contact with the back surface 34 of the second solar cell 30 (e.g. the back-finger electrode 38). In particular, the contact area of the second surface 52 is defined by the width of the coating 60 which forms between the second surface 52 and the back surface 34 of the solar cell, as shown by the in FIG. 3B. Accordingly, since the first surface 50 has a wider cross-sectional width (i.e. contact width) than the second surface 52, the contact width of the first surface 50 is also greater than the contact area defined by the second surface 52.

[0142] The curved configuration of the second surface 52 causes the coating 60 to flow towards the upper central point of the second surface 52. This arrangement of the second surface 52 also causes the coating 60 to wet onto the back surface 34 of the second solar cell 30, which narrows the width of the contact area between the conductive element 18 and the second solar cell 30. Considering the front connector 12a, the curved second surface 52 also provides a light scattering surface on the front surface 22 of the first solar cell 20, as illustrated by the dashed arrows in FIG. 3A

[0143] It will be understood that the first and second contact areas are also defined, at least in part, by the length of each conductive element 18 which is configured to overlay the respective front and back surfaces 22, 34 of first and second solar cells 20, 30 (i.e. the length of the first and second conductive element portions 18a, 18b associated with the front and back connectors 12a, 12b , respectively).

[0144] The electrode assembly 12 is configured such that the length of the portion 18a of the conductive elements 18 which overlays the front surface 22 of the first solar cell 20 is equal to the length of the conductive element portion 18b which overlays the back surface 34 of the second solar cell 30. Accordingly, the difference in the respective contact areas is defined by the contact width of the respective first and second surfaces 50, 52 of the conductive elements 18.

[0145] According to an exemplary arrangement, the conductive elements 18 may comprise a third and a fourth surface 54, 56 arranged between the first and second surfaces 50, 52, as shown in FIGS. 5, 6, 8 and 9. The fourth surface 56 is arranged opposite the third surface 54, and they each space apart the first surface 50 from the second surface 52 to define a depth of the conductive element 18.

[0146] According to each of these exemplary arrangements, the second surfaces 52 are configured to be substantially flat. The flat second surface 52 is arranged to be parallel to the first surface 50 and the respective front and back surfaces 22, 34 of the first and second solar cells 20, 30. Compared to the curved second surface, the flat second surface 52 provides a more robust electrical contact with the second solar cell 30 whilst still providing some light scattering when arranged on the front surface of the first solar cell 20.

[0147] The third and fourth surfaces 54, 56 may be configured with a convex curved surface, as shown in FIGS. 5 and 7. In these arrangements, the conductive element 18 comprises a cross sectional shape which defines a truncated semi-circle. Alternatively, the third and fourth surfaces 54, 56 may be substantially flat such that the conductive element's cross-section defines a truncated triangle, as shown in FIGS. 6 and 9.

[0148] The conductive elements 18 are configured such that they each comprise a cross sectional shape which is non-symmetrical about a central lateral plane CL of the conductive element 18, as shown by the dashed horizontal line in FIGS. 4 to 6. The central lateral plane CL defines a plane which extends in a width wise, or horizontal, direction through the longitudinal axis of the conductive element 18. The conductive elements 18 are also configured such that they comprise a cross sectional shape which is symmetrical about a central vertical plane CV of the conductive element 18. The central vertical plane CV defines a plane which extends in a depth wise, or vertical, direction through the longitudinal axis of the conductive element 18, as shown by the vertical dashed lines in FIGS. 4 to 6.

[0149] In each of the exemplary arrangements shown in FIGS. 4 to 9, the coating 60 is configured to substantially cover the first and second surfaces 50, 52. As shown in FIG. 4, the coating 60 is arranged to only cover the portion of the second surface 52 which is configured to make contact with a solar cell surface (e.g. the back surface 34 of the second solar cell 30). In the exemplary arrangements where the conductive elements 18 comprise a third and fourth surface 54, 56, then the coating 60 is only arranged on the first and second surfaces 50, 52, as shown in FIGS. 5 and 6. Alternatively, each of the surfaces of the conductive element may be coated in the coating 60, as shown in FIGS. 7 to 9.

[0150] The coating 60 is an electrically conductive material having a melting point which is lower than that of the conductive element 18. The coating 60 comprises a metal alloy formed of at least two or more components, such as a lead based, tin based and bismuth-based alloy. Alternatively, the coating 60 may comprise a 2-phase, 3-phase, or more complex metal alloy, as would be understood by the skilled person.

[0151] In the exemplary arrangements shown in FIGS. 3A, 3B and 4 to 9, each conductive element 18 is configured with a constant cross-section along its length. Each conductive element 18 is arranged such that the first and second surfaces 50, 52 maintain their respective positions on the conductive element 18, as the element extends and connects between the first solar cell 20 and the second solar cell 30. In this way, each conductive element 18 is configured so as not to comprise any axial twists or turns along its length.

[0152] Each of the conductive elements 18 is formed from a single wire portion (i.e. the first and second portions 18a, 18b of each conductive element 18 are integrally formed with each other). In this way, the conductive elements 18 provide a direct electrical connection between the first and second solar cells 20, 30, which increases the flow of current therebetween. Configuring the conductive elements in this way removes the need to provide separate connections (such as copper ribbons) between neighbouring solar cells, which thereby reduces the number and complexity of manufacturing steps required to fabricate the solar cell assembly 10.

[0153] An exemplary method of manufacturing the solar cell assembly 10 will now be described with reference to FIGS. 10A to 15B, which illustrate the steps of the manufacturing method. Reference will also be made to FIG. 16, which shows a flow chart of the corresponding method steps.

[0154] The method commences with a first step 202 in which there is provided a first solar cell 20, a second solar cell 30 and an electrode assembly 12, as described above. Prior to the first step 202, the solar cells are manufactured in a conventional manner as would be understood by the person having ordinary skill in the art. In particular, the method includes configuring each of the solar cells with a conductive surface (or conductive portion) on their respective front and back surfaces. For example, this may be achieved through the deposition of electrically conductive material onto the front and back surfaces 22, 34 of the first and second solar cells 20, 30 to form the pluralities of front and back finger electrodes 36, 38, respectively.

[0155] According to an exemplary method, the finger electrodes 36, 38 are deposited onto their respective surfaces using a screen-printing process. The screen-printing process includes laying down a printable precursor onto the layered structure surface through a screen, or mask. The printable precursor comprises a metal paste which is obtained by mixing metal powder together with glass frit in the presence of a suitable solvent. Openings in the mask determine the respective arrangement and dimensions of the printed features (i.e. the finger electrodes). Once the printable precursor is provided onto the solar cell surface, it is then fired in a furnace to form the corresponding finger electrodes.

[0156] The electrode assembly 12 may be formed by arranging a plurality of conductive elements 18 together with respective first and second portions of film 42, 44 in order to define the front and back connector 12a, 12b of the electrode assembly 12.

[0157] Once the plurality of finger electrodes 36, 38 are deposited onto the surfaces of the first and second solar cells 20, 30, the electrode assembly 12 can be connected to the solar cells 20, 30 to define a solar assembly 10, according to the present invention.

[0158] In step 204, the second solar cell 30 is arranged so that its back surface 34 faces upward, as shown in FIGS. 10A and 10B, for example. Once the second solar cell 30 is inverted, then in step 206 the back connector 12b of the electrode assembly 12 is overlaid onto the back surface 34 of the second solar cell 30. Accordingly, the conductive elements 18 are overlaid onto the back surface 34 such that they sit perpendicular to the finger electrodes 38, as shown in FIG. 11B. As a result of method step 206, the second surfaces 52 of the conductive elements 18 are brought into contact with the back-finger electrodes 34 of the solar cell.

[0159] In step 208, the second surface 52 of the plurality of conductive elements 18 is connected to the back surface 34 of the second solar cell 30. This method step involves heating and/or applying pressure to the conductive elements 18 in the second connector 12b to bond the coating 60 to the second solar cell's back surface 34 under a compressive force, as illustrated in FIG. 11B.

[0160] The application of heat and pressure causes the coating 60 on the second surface 52 of the conductive elements 18 to flow due to gravity towards the back surface 34 of the second solar cell 30. The coating 60 wets against the solar cell surface. Also, the curvature of the conductive element's second surface 52 causes the coating 60 to build-up, or pool, at the interface between the solar cell and the conductive element.

[0161] Once the coating has cooled and solidified, it forms an ohmic contact with the underlying back-finger electrodes 38, as shown in FIG. 12B. The application of heat and pressure also laminates the back film 44 onto the back surface 34 of the solar cell 30.

[0162] The method proceeds with step 210 in which the first solar cell 20 is inverted and overlaid onto the front connector 12a, as shown in FIGS. 10A and 10B. In so doing, the first surfaces 50 of the conductive elements' front portions 18a are brought into contact with the front surface 22 of the first solar cell 20.

[0163] In step 212, the first surfaces 50 of the plurality of conductive elements 18 are then connected to the front surface 22 of the first solar cell 20. Like step 208, the method involves heating and/or applying pressure to the conductive elements 18 of the first connector 12a to physically bond them to the first solar cell's front surface 22 under a compressive force, as illustrated in FIG. 14B. The application of heat and pressure cause the coating 60 on the conductive elements' first surfaces 50 to melt and then wet against the first solar cell's front surface 22. The planar first surface 50 is configured to retain the molten coating 60 in position at the interface with the solar cell 20 whilst the coating 60 cools and solidifies to form an ohmic contact therebetween. The application of heat and pressure also laminates the front film 42 onto the first solar cell's front surface 22, as shown in FIG. 15B.

[0164] In embodiments, the front plate 104 of the solar module 100 is made of glass whilst the rear plate 108 is made from a lighter polymer sheet. In this case, a further advantage of assembling the solar cell assembly 10 with the inverted solar cells 20, 30 is that it's easier to build up the solar assembly 10 onto the heavier front plate 104 and then cover it with the lighter back plate 108. This reduces the risk of damaging the solar module 100 compared with having to arrange the heavier glass front plate 104 into position on top of a pre-assembled solar assembly 10.

[0165] It will be appreciated that at least some of the above described method steps may be undertaken concurrently or in any order. For example, the method steps which involve inverting and arranging the first and second solar cells 20, 30 with respect to the electrode assembly 12 may take place at substantially the same time. Similarly, the front and back connectors 12a, 12b may also be connected to the respective front and back surfaces 22, 34 of the first and second solar cells 20, 30 at the same time.

[0166] As a result of the above described method, the front and back connectors 12a, 12b of the electrode assembly 12 are both mechanically and electrically coupled to the respective first and second solar cells 20, 30 to form a solar cell assembly 10 according to the present invention.

[0167] It will be understood that the invention is not limited to the embodiments above described and various modifications and improvements can be made without departing from the concepts described herein. Except where mutually exclusive, any of the features may be employed separately or in combination with any other features and the disclosure extends to and includes all combinations and sub-combinations of one or more features described herein.

FEATURE LIST

[0168] Solar cell assembly 10 [0169] Electrode assembly 12, 14, 16 [0170] Front connector 12a [0171] Back connector 12b [0172] Interconnecting portion 12c [0173] Conductive element 18 [0174] First portion of the conductive elements 18a [0175] Second portion of the conductive elements 18b [0176] Third portion of the conductive elements 18c [0177] First solar cell 20 [0178] Front surface 22 [0179] Back surface 24 [0180] Front finger electrodes 26 [0181] Back finger electrodes 28 [0182] Second solar cell 30 [0183] Front surface 32 [0184] Back surface 34 [0185] Front finger electrodes 36 [0186] Back finger electrodes 38 [0187] Film 40 [0188] Front film portion 42 [0189] Back film portion 44 [0190] Conductive element-first surface 50 [0191] Conductive element-second surface 52 [0192] Conductive element-third surface 54 [0193] Conductive element-fourth surface 56 [0194] Coating 60 [0195] Solar module 100 [0196] Support assembly 102 [0197] Front plate 104 [0198] Central chamber 106 [0199] Back plate 108 [0200] Method steps 200 to 212