SOLAR CELL INTERCONNECTION, MODULE AND PANEL METHOD

• US 20110300664A1
• Filed: 06/07/2011
• Published: 12/08/2011
• Est. Priority Date: 06/08/2010
• Status: Active Grant

• Current Assignee: Amerasia International Technology, Inc.
• Original Assignee: Amerasia International Technology, Inc.
• Inventors: CHUNG, Kevin Kwong-Tai
• Granted Patent: US 8,394,650 B2
• Time in Patent Office: Days
• US Class Current: 438/80
• CPC Class Codes: B32B 17/10018 comprising only one glass sheet
• CPC Class Codes: B32B 17/10871 in combination with particular heat treatment
• CPC Class Codes: H01L 31/02013 comprising output lead wires elements
• CPC Class Codes: H01L 31/048 Encapsulation of modules
• CPC Class Codes: H01L 31/0512 made of a particular material or composition of materials
• CPC Class Codes: H01L 31/1876 Particular processes or apparatus for batch treatment of the devices
• CPC Class Codes: Y02E 10/50 Photovoltaic [PV] energy
• CPC Class Codes: Y02P 70/50 Manufacturing or production processes characterised by the final manufactured product

Abstract

A laminated module or panel of solar cells and a laminating method for making same comprise a top layer of melt flowable optically transparent molecularly flexible thermoplastic and a rear sheet of melt flowable insulating molecularly flexible thermoplastic both melt flowing at a temperature between about 80° C. and 250° C. and having a low glass transition temperature. Solar cells are encapsulated by melt flowing the top layer and rear sheet, and electrical connections are provided between front and back contacts thereof. Light passing through the transparent top layer impinges upon the solar cells and the laminated module exhibits sufficient flexural modulus without cross-linking chemical curing. Electrical connections may be provided by melt flowable electrically conductive molecularly flexible thermoplastic adhesive or by metal strips or by both.

Claims

1. A method for making a laminated module of solar cells having front and back surfaces comprising:

obtaining a top layer of a melt flowable optically transparent electrically insulating thermoplastic adhesive material having a first pattern of melt flowable electrically conductive thermoplastic adhesive thereon for making electrical connection to the front surface of solar cells;

placing a plurality of solar cells having front and back surfaces to which electrical connection may be made on the melt flowable top layer in locations with the first pattern of melt flowable electrically conductive thermoplastic adhesive adjacent the front surfaces of the plurality of solar cells,

whereby an electrical connection may be made between the first pattern of melt flowable electrically conductive thermoplastic adhesive and the front surfaces of the plurality of solar cells;

obtaining a rear sheet of a melt flowable electrically insulating thermoplastic adhesive material having a second pattern of melt flowable electrically conductive thermoplastic adhesive thereon for making electrical connection to the rear surface of the solar cells;

placing the melt flowable rear sheet adjacent to the melt flowable top layer and the back surfaces of the plurality of solar cells in a location with the second pattern of melt flowable electrically conductive thermoplastic adhesive adjacent the back surfaces of the plurality of solar cells;

heat laminating the melt flowable top layer, the plurality of solar cells and the melt flowable rear sheet to melt flow the melt flowable top layer and the melt flowable rear sheet together so that electrical connections are made between the first pattern of melt flowable electrically conductive thermoplastic adhesive and the front surfaces of the plurality of solar cells, between the second pattern of melt flowable electrically conductive thermoplastic adhesive and the back surfaces of the plurality of solar cells, and between the first and second patterns of pattern of melt flowable electrically conductive thermoplastic adhesive;

whereby the plurality of solar cells are embedded into at least the melt flowable top layer, and

whereby ones of the plurality of solar cells are electrically connected in series by the connection between the first and second patterns of electrically conductive thermoplastic adhesive.

2. The method of claim 1 wherein said obtaining a top layer of a melt flowable optically transparent electrically insulating thermoplastic adhesive material includes:

applying the first pattern of melt flowable electrically conductive thermoplastic adhesive on one surface of the top layer of melt flowable optically transparent electrically insulating thermoplastic adhesive material,

wherein the first pattern includes at least one elongated conductor for making electrical connection to the front surface of solar cells.

3. The method of claim 2 wherein said applying the first pattern includes:

applying the first pattern of melt flowable electrically conductive thermoplastic adhesive by screening, stenciling, roll coating, masking, deposition, printing, screen printing, inkjet printing, or sheet laminating;

or

patterning an electrically conductive metal on the sheet in the first pattern and applying the first pattern of melt flowable electrically conductive thermoplastic adhesive on the patterned electrically conductive metal by screening, stenciling, roll coating, masking, deposition, printing, screen printing, inkjet printing, or sheet laminating.

4. The method of claim 2 wherein said applying the first pattern includes:

applying an insulating pattern of a melt flowable electrically insulating thermoplastic adhesive on the first pattern of melt flowable electrically conductive thermoplastic adhesive, wherein the insulating pattern has a plurality of elongated areas at locations corresponding to locations at which the edges of the plurality of solar cells are to be placed.

5. The method of claim 1 wherein:

said placing a plurality of solar cells includes placing solar cells in locations with portions of the first pattern of melt flowable electrically conductive thermoplastic adhesive extending beyond edges of the plurality of solar cells; and

said placing the melt flowable rear sheet adjacent to the melt flowable top layer includes placing the rear sheet in a location with portions of the second pattern of melt flowable electrically conductive thermoplastic adhesive extending beyond edges of the plurality of solar cells opposite the extending portions of the first pattern of electrically conductive thermoplastic adhesive;

wherein electrical connections are made between the respective extending portions of the first and second patterns of pattern of melt flowable electrically conductive thermoplastic adhesive.

6. The method of claim 1 wherein said obtaining a rear sheet of a melt flowable electrically insulating thermoplastic adhesive material includes:

applying the second pattern of melt flowable electrically conductive thermoplastic adhesive on one surface of the rear sheet of melt flowable electrically insulating thermoplastic adhesive material,

wherein the second pattern includes at least one conductor for making electrical connection to the back surface of solar cells.

7. The method of claim 6 wherein said applying the second pattern includes:

applying the second pattern of melt flowable electrically conductive thermoplastic adhesive by screening, stenciling, roll coating, masking, deposition, printing, screen printing, inkjet printing, or sheet laminating;

or

patterning an electrically conductive metal on the sheet in the second pattern and applying the second pattern of melt flowable electrically conductive thermoplastic adhesive on the patterned electrically conductive metal by screening, stenciling, roll coating, masking, deposition, printing, screen printing, inkjet printing, or sheet laminating.

8. The method of claim 1 wherein said placing a plurality of solar cells includes:

placing the front surfaces of the solar cells adjacent to the first pattern of melt flowable electrically conductive thermoplastic adhesive while the melt flowable electrically conductive thermoplastic adhesive is wet;

or

placing the front surfaces of the solar cells adjacent to the first pattern of melt flowable electrically conductive thermoplastic adhesive after the melt flowable electrically conductive thermoplastic adhesive is dried;

or

placing the front surfaces of the solar cells adjacent to the first pattern of melt flowable electrically conductive thermoplastic adhesive after the melt flowable electrically conductive thermoplastic adhesive is B-staged.

9. The method of claim 1 wherein:

each of the plurality of solar cells includes a transparent electrically conductive front contact substantially covering the front surface thereof and the first pattern includes for each of the plurality of solar cells at least one elongated conductor having a plurality of relatively narrower elongated conductors extending substantially perpendicular thereto for making an electrical connection to the front contact of the solar cell;

or

each of the plurality of solar cells includes at least one elongated electrically conductive front contact on the front surface thereof and the first pattern includes for each of the plurality of solar cells at least one elongated conductor corresponding to the at least one elongated electrically conductive front contact of the solar cell and located for making an electrical connection to the front contact of the solar cell;

or

each of the plurality of solar cells includes at least two parallel elongated electrically conductive front contacts on the front surface thereof and the first pattern includes for each of the plurality of solar cells at least two parallel elongated conductors corresponding to the at least two parallel elongated electrically conductive front contacts of the solar cell and located for making an electrical connection to the front contacts of the solar cell.

10. The method of claim 1 wherein each of the plurality of solar cells has a contact on the front surface thereof to which electrical connection may be made, wherein said placing a plurality of solar cells on the melt flowable top layer includes heating the top layer, the solar cells, or both, so as to increase the adhesion of the solar cells to the top layer.

11. The method of claim 1 wherein the first pattern of melt flowable electrically conductive thermoplastic adhesive or the second pattern of melt flowable electrically conductive thermoplastic adhesive or both comprise:

at least one elongated continuous strip of melt flowable electrically conductive thermoplastic adhesive where said plurality of solar cells do not have a metalized contact on the front surface and/or on the back surface thereof;

or

a plurality of areas comprising between about ten percent and 100 percent of the area of metalized contact where said plurality of solar cells have a metalized contact on the front surface and/or on the back surface thereof.

12. The method of claim 1 wherein each of said plurality of solar cells includes an electrically conductive tab applied to a contact on the front surface or on the back surface thereof or on both surfaces thereof, said tab extending beyond an edge of the solar cell, and wherein said electrically conductive tab includes:

a solderable metal strip soldered to a metalized contact of the solar cell;

or

a metal strip having on opposing broad surfaces thereof a plurality of areas comprising melt flowable electrically conductive thermoplastic adhesive covering between about ten percent and 100 percent of the area of said metal strip and melt flowable electrically insulating thermoplastic adhesive substantially covering the remaining area of said metal strip.

13. The method of claim 1 wherein said heat laminating includes:

heat laminating the melt flowable top layer and the plurality of solar cells thereon to melt flow the melt flowable top layer so that electrical connections are made between the first pattern of melt flowable electrically conductive thermoplastic adhesive and the front surfaces of the plurality of solar cells and the plurality of solar cells are embedded into the melt flowable top layer.

14. The method of claim 13 wherein said heat laminating includes:

heat laminating the melt flowed top layer with the plurality of solar cells embedded therein and the melt flowable rear sheet to melt flow the melt flowable top layer and the melt flowable rear sheet together so that electrical connections are made between the second pattern of melt flowable electrically conductive thermoplastic adhesive and the back surfaces of the plurality of solar cells, and between the respective extending portions of the first and second patterns of pattern of melt flowable electrically conductive thermoplastic adhesive;

whereby ones of the plurality of solar cells are electrically connected in series by the connection between the first and second patterns of electrically conductive thermoplastic adhesive.

15. The method of claim 1 wherein said heat laminating includes:

heat laminating a glass layer on an exposed front surface of the melt flowable optically transparent top layer;

or

heat laminating a thermally conductive layer on an exposed rear surface of the melt flowable rear sheet;

or

heat laminating a glass layer on an exposed front surface of the melt flowable optically transparent top layer and a thermally conductive layer on an exposed rear surface of the melt flowable rear sheet.

16. The method of claim 1 wherein said heat laminating comprises:

rolling heat laminating;

or

rolling heat laminating employing heated laminating rollers;

or

rolling heat laminating employing a release liner between at least the top layer and the laminating rollers;

or

rolling heat laminating employing a release liner between at least the rear sheet and the laminating rollers;

or

rolling heat laminating employing one or more heating elements for heating at least the top layer prior to the laminating rollers;

or

rolling heat laminating employing one or more heating elements for heating at least the rear sheet prior to the laminating rollers;

or

vacuum laminating;

or

any combination of the foregoing.

17. The method of claim 1 wherein said heat laminating further comprises:

placing a release liner adjacent at least the top layer; and

placing a backing sheet that is stiffer than the top layer against the release liner for defining a surface to which the top layer conforms when heat laminated.

18. The method of claim 1 wherein said obtaining a top layer includes obtaining a roll or sheet including a plurality of top layers, said method further comprising:

separating a roll laminated roll or sheet including a plurality of top layers into a plurality of individual top layers.

19. The method of claim 1 wherein said obtaining a rear sheet includes obtaining a roll or sheet including a plurality of rear sheets, said method further comprising:

separating a roll laminated roll or sheet including a plurality of rear sheets into a plurality of individual rear sheets.

20. The method of claim 1 wherein said laminated module of solar cells comprises a laminated solar cell panel.

21. A method for making a laminated module of solar cells having front and back surfaces comprising:

obtaining a top layer of a melt flowable optically transparent electrically insulating thermoplastic adhesive material having a first pattern of melt flowable electrically conductive thermoplastic adhesive thereon for making electrical connection to the front surface of solar cells;

placing a plurality of solar cells having front and back surfaces to which electrical connection may be made on the melt flowable top layer in locations with the first pattern of melt flowable electrically conductive thermoplastic adhesive adjacent the front surfaces of the plurality of solar cells,

whereby light may pass through said melt flowable optically transparent top layer to impinge upon the front surface of said plurality of solar cells and connection may be made to the back surfaces thereof;

heat laminating the melt flowable top layer and the plurality of solar cells to melt flow the melt flowable top layer so that electrical connections are made between the first pattern of melt flowable electrically conductive thermoplastic adhesive and the front surfaces of the plurality of solar cells;

wherein the plurality of solar cells are embedded into the melt flowable top layer,

wherein the first pattern of melt flowable electrically conductive thermoplastic adhesive provides exposed electrical connections to the front surfaces of said plurality of solar cells, and

wherein the back surfaces of said plurality of solar cells are exposed for making electrical connection thereto,

whereby electrical connections to the front and back surfaces of said plurality of solar cells are exposed on the same surface of said laminated module of solar cells.

22. The method of claim 21 further comprising:

obtaining a rear sheet of a melt flowable electrically insulating thermoplastic adhesive material having a second pattern of melt flowable electrically conductive thermoplastic adhesive thereon for making electrical connection to the rear surface of the solar cells;

placing the melt flowable rear sheet adjacent to the melt flowable top layer and the back surfaces of the plurality of solar cells in a location with the second pattern of melt flowable electrically conductive thermoplastic adhesive adjacent the back surfaces of the plurality of solar cells with portions of the second pattern of melt flowable electrically conductive thermoplastic adhesive extending beyond edges of the plurality of solar cells opposite the extending portions of the first pattern of electrically conductive thermoplastic adhesive;

heat laminating the melt flowable top layer, the plurality of solar cells and the melt flowable rear sheet to melt flow the melt flowable top layer and the melt flowable rear sheet together so that electrical connections are made between the second pattern of melt flowable electrically conductive thermoplastic adhesive and the back surfaces of the plurality of solar cells, and between the respective extending portions of the first and second patterns of pattern of melt flowable electrically conductive thermoplastic adhesive;

whereby the plurality of solar cells are embedded into at least the melt flowable top layer, and

whereby ones of the plurality of solar cells are electrically connected in series by the connection between the first and second patterns of electrically conductive thermoplastic adhesive.

23. The method of claim 21 wherein said obtaining a top layer of a melt flowable optically transparent electrically insulating thermoplastic adhesive material includes:

applying the first pattern of melt flowable electrically conductive thermoplastic adhesive on one surface of the top layer of melt flowable optically transparent electrically insulating thermoplastic adhesive material,

wherein the first pattern includes at least one elongated conductor for making electrical connection to the front surface of solar cells.

24. The method of claim 23 wherein said applying the first pattern includes:

applying the first pattern of melt flowable electrically conductive thermoplastic adhesive by screening, stenciling, roll coating, masking, deposition, printing, screen printing, inkjet printing, or sheet laminating;

or

patterning an electrically conductive metal on the sheet in the first pattern and applying the first pattern of melt flowable electrically conductive thermoplastic adhesive on the patterned electrically conductive metal by screening, stenciling, roll coating, masking, deposition, printing, screen printing, inkjet printing, or sheet laminating.

25. The method of claim 23 wherein said applying the first pattern includes:

applying an insulating pattern of a melt flowable electrically insulating thermoplastic adhesive on the first pattern of melt flowable electrically conductive thermoplastic adhesive, wherein the insulating pattern has a plurality of elongated areas at locations corresponding to locations at which the edges of the plurality of solar cells are to be placed.

26. The method of claim 21 wherein:

said placing a plurality of solar cells includes placing solar cells in locations with portions of the first pattern of melt flowable electrically conductive thermoplastic adhesive extending beyond edges of the plurality of solar cells,

wherein the portions of the first pattern of melt flowable electrically conductive thermoplastic adhesive extending beyond solar cells are exposed near the back surfaces of said plurality of solar cells to provide the exposed electrical connections to the front surfaces of said plurality of solar cells.

27. The method of claim 21 wherein said placing a plurality of solar cells includes:

placing the front surfaces of the solar cells adjacent to the first pattern of melt flowable electrically conductive thermoplastic adhesive while the melt flowable electrically conductive thermoplastic adhesive is wet;

or

placing the front surfaces of the solar cells adjacent to the first pattern of melt flowable electrically conductive thermoplastic adhesive after the melt flowable electrically conductive thermoplastic adhesive is dried;

or

placing the front surfaces of the solar cells adjacent to the first pattern of melt flowable electrically conductive thermoplastic adhesive after the melt flowable electrically conductive thermoplastic adhesive is B-staged.

28. The method of claim 21 wherein:

each of the plurality of solar cells includes a transparent electrically conductive front contact substantially covering the front surface thereof and the first pattern includes for each of the plurality of solar cells at least one elongated conductor having a plurality of relatively narrower elongated conductors extending substantially perpendicular thereto for making an electrical connection to the front contact of the solar cell;

or

each of the plurality of solar cells includes at least one elongated electrically conductive front contact on the front surface thereof and the first pattern includes for each of the plurality of solar cells at least one elongated conductor corresponding to the at least one elongated electrically conductive front contact of the solar cell and located for making an electrical connection to the front contact of the solar cell;

or

each of the plurality of solar cells includes at least two parallel elongated electrically conductive front contacts on the front surface thereof and the first pattern includes for each of the plurality of solar cells at least two parallel elongated conductors corresponding to the at least two parallel elongated electrically conductive front contacts of the solar cell and located for making an electrical connection to the front contacts of the solar cell.

29. The method of claim 21 wherein each of the plurality of solar cells has a contact on the front surface thereof to which electrical connection may be made, wherein said placing a plurality of solar cells on the melt flowable top layer includes heating the top layer, the solar cells, or both, so as to increase the adhesion of the solar cells to the top layer.

30. The method of claim 21 wherein the first pattern of melt flowable electrically conductive thermoplastic adhesive comprises:

at least one elongated continuous strip of melt flowable electrically conductive thermoplastic adhesive where said plurality of solar cells do not have a metalized contact on the front surface thereof;

or

a plurality of areas comprising between about ten percent and 100 percent of the area of metalized contact where said plurality of solar cells have a metalized contact on the front surface thereof.

31. The method of claim 21 wherein each of said plurality of solar cells includes an electrically conductive tab applied to a contact on the front surface or on the back surface thereof or on both surfaces thereof, said tab extending beyond an edge of the solar cell, and wherein said electrically conductive tab includes:

a solderable metal strip soldered to a metalized contact of the solar cell;

or

a solderable metal strip soldered to a metalized contact on the front surface of one solar cell and to a metalized contact on the back surface of an adjacent solar cell;

or

a metal strip having on opposing broad surfaces thereof a plurality of areas comprising melt flowable electrically conductive thermoplastic adhesive covering between about ten percent and 100 percent of the area of said metal strip and melt flowable electrically insulating thermoplastic adhesive substantially covering the remaining area of said metal strip;

or

a metal strip having on opposing broad surfaces thereof a plurality of areas comprising melt flowable electrically conductive thermoplastic adhesive covering between about ten percent and 100 percent of the area of said metal strip and melt flowable electrically insulating thermoplastic adhesive substantially covering the remaining area of said metal strip, wherein areas of melt flowable electrically conductive thermoplastic adhesive on one surface of said metal strip adhere to a metalized contact on the front surface of one solar cell and areas of melt flowable electrically conductive thermoplastic adhesive on the other surface of said metal strip adhere to a metalized contact on the back surface of an adjacent solar cell.

32. The method of claim 21 wherein said heat laminating includes:

heat laminating a glass layer on an exposed front surface of the melt flowable optically transparent top layer.

33. The method of claim 21 wherein said heat laminating comprises:

rolling heat laminating;

or

rolling heat laminating employing heated laminating rollers;

or

rolling heat laminating employing a release liner between at least the top layer and the laminating rollers;

or

rolling heat laminating employing one or more heating elements for heating at least the top layer prior to the laminating rollers;

or

vacuum laminating;

or

any combination of the foregoing.

34. The method of claim 21 wherein said heat laminating further comprises:

placing a release liner adjacent at least the top layer; and

placing a backing sheet that is stiffer than the top layer against the release liner for defining a surface to which the top layer conforms when heat laminated.

35. The method of claim 21 wherein said obtaining a top layer includes obtaining a roll or sheet including a plurality of top layers, said method further comprising:

separating a roll laminated roll or sheet including a plurality of top layers into a plurality of individual top layers.

36. A method for making a laminated module of solar cells having front and back surfaces comprising:

obtaining a top layer of a melt flowable optically transparent electrically insulating molecularly flexible thermoplastic adhesive material having at least ten percent molecular crystallites that melt flow at a temperature in the range between about 80°

C. and about 250°

C. and having a glass transition temperature of less than about 0°

C.;

to bond to the front surfaces of solar cells;

placing a plurality of solar cells having front and back surfaces to which electrical connection may be made with the front surfaces thereof adjacent the melt flowable top layer;

providing electrical connections between the front surface of ones of the plurality of solar cells and the back surface of others of said plurality of solar cells;

placing adjacent the back surfaces of the plurality of solar cells and top sheet a rear sheet of a melt flowable electrically insulating molecularly flexible thermoplastic adhesive material having at least ten percent molecular crystallites that melt flow at a temperature in the range between about 80°

C. and about 250°

C. and having a glass transition temperature of less than about 0°

C.;

to bond to the back surfaces of solar cells;

heat laminating the melt flowable top layer, the plurality of solar cells and the melt flowable rear sheet to melt flow the melt flowable top layer and the melt flowable rear sheet together so that the plurality of solar cells and the electrical connections there between are encapsulated in the melt flowed molecularly flexible thermoplastic adhesive of at least the top layer;

whereby light may pass through the melt flowed optically transparent top layer to impinge upon the front surface of the plurality of solar cells;

wherein the laminated module including the top layer and the rear sheet exhibits a flexural modulus at about 60°

C. that is at least fifty percent of the flexural modulus exhibited at about 20°

C. without cross-linking chemical curing.

37. The method of claim 36 wherein said providing electrical connections comprises:

providing a first pattern of melt flowable electrically conductive thermoplastic adhesive on the top layer in locations for making electrical connection to the front surfaces of the plurality of solar cells;

providing a second pattern of melt flowable electrically conductive thermoplastic adhesive on the rear sheet in locations for making electrical connection to the back surfaces of the plurality of solar cells,

wherein each of the first and second patterns of melt flowable electrically conductive thermoplastic adhesive include respective portions extending beyond the edges of the plurality of solar cells that melt flow connect to each other to provide an electrical connection between the front surface of one of the plurality of solar cells and the back surface of another of the plurality of solar cells,

whereby ones of the plurality of solar cells are electrically connected in series by the connection between the first and second patterns of electrically conductive thermoplastic adhesive.

38. The method of claim 36 wherein said providing electrical connections comprises:

providing at least one elongated continuous strip of melt flowable electrically conductive thermoplastic adhesive where the plurality of solar cells do not have a metalized contact on the front surface and/or on the back surface thereof;

or

providing a plurality of areas comprising between about ten percent and 100 percent of the area of metalized contact where the plurality of solar cells have a metalized contact on the front surface and/or on the back surface thereof.

39. The method of claim 36 wherein said providing electrical connections comprises:

applying an electrically conductive tab to a contact on the front surface or on the back surface of or on both surfaces of each of the plurality of solar cells, each tab extending beyond an edge of the solar cell, wherein the electrically conductive tab includes;

a solderable metal strip soldered to a metalized contact of the solar cell;

or

a metal strip having on opposing broad surfaces thereof a plurality of areas comprising melt flowable electrically conductive thermoplastic adhesive covering between about ten percent and 100 percent of the area of the metal strip and melt flowable electrically insulating thermoplastic adhesive substantially covering the remaining area of the metal strip, attached to a metalized contact of the solar cell.

40. The method of claim 36 wherein said providing electrical connections comprises:

soldering solderable metal strips to metalized contacts of the plurality of solar cells;

or

attaching metal strips having on opposing broad surfaces thereof a plurality of areas comprising melt flowable electrically conductive thermoplastic adhesive covering between about ten percent and 100 percent of the area of the metal strip and melt flowable electrically insulating thermoplastic adhesive substantially covering the remaining area of the metal strip, to metalized contacts of the plurality of solar cells.