Solar cell having a front-mounted bypass diode

• US 20020144724A1
• Filed: 09/17/2001
• Published: 10/10/2002
• Est. Priority Date: 08/20/1998
• Status: Active Grant

• Current Assignee: Emcore Solar Power, Inc. (Emcore Corporation)
• Original Assignee: Emcore Corporation
• Inventors: DeWitt, Mark, Hanley, James Patrick, Chiang, Peng-Kuen, Kilmer, Louis C.
• Granted Patent: US 6,617,508 B2
• Time in Patent Office: Days
• US Class Current: 136/244
• CPC Class Codes: B64G 1/443 Photovoltaic cell arrays
• CPC Class Codes: H01L 27/1421 comprising bypass diodes integrated or directly associated with the device, e.g. bypass diode integrated or formed in or on the same substrate as the solar cell
• CPC Class Codes: H01L 31/0508 the interconnection means having a particular shape
• CPC Class Codes: H01L 31/06875 inverted grown metamorphic [IMM] multiple junction solar cells, e.g. III-V compounds inverted metamorphic multi-junction cells
• CPC Class Codes: H01L 31/1852 comprising a growth substrate not being an AIIIBV compound
• CPC Class Codes: Y02E 10/544 Solar cells from Group III-V materials
• CPC Class Codes: Y02P 70/50 Manufacturing or production processes characterised by the final manufactured product
• CPC Class Codes: Y10S 136/293 Circuits

Abstract

An efficient method of interconnecting a solar cell having at least two front surface contacts with a diode mounted on a front surface of the solar cell includes the act of forming at least a first recess on a front surface of the solar cell. A first solar cell contact is formed on the front surface in the first recess. A second solar cell contact is formed on the front surface. At least a first bypass diode is positioned at least partly within the recess. The bypass diode has a first diode contact and a second diode contact. The first solar cell contact is interconnected with the first diode contact. The second solar cell contact is interconnected with the second diode contact.

Claims

1. An efficient method of interconnecting a solar cell having at least two front surface contacts with a diode mounted on a front surface of said solar cell, said method comprising the acts of:

forming at least a first recess on a front surface of said solar cell;

forming a first solar cell contact on said front surface in said first recess;

forming a second solar cell contact on said front surface;

positioning at least a first bypass diode at least partly within said recess, said bypass diode having a first diode contact and a second diode contact;

interconnecting said first solar cell contact with said first diode contact; and

interconnecting said second solar cell contact with said second diode contact.

2. The method of interconnecting a solar cell with a diode as defined in claim 1, wherein said act of forming said recess further comprises the act of using a mesa etch process to form the recess down to a solar cell substrate.

3. The method of interconnecting a solar cell with a diode as defined in claim 1, wherein said act of forming said first solar cell contact comprises the act of using photoresist patterning process to form said contacts.

4. The method of interconnecting a solar cell with a diode as defined in claim 1, further comprising the act of bonding a ceria-doped coverglass over said solar cell, said coverglass defining a notch having an area at least the size of an area of said recess.

5. The method of interconnecting a solar cell with a diode as defined in claim 1, wherein said act of interconnecting said first solar cell contact with said first diode contact further comprises the act of physically bonding a first interconnect to said first solar cell contact and to said first diode contact.

6. The method of interconnecting a solar cell with a diode as defined in claim 5, wherein said act of interconnecting said second solar cell contact with said second diode contact further comprises the act of welding a second interconnect to said second solar cell contact and said second diode contact.

7. A solar cell assembly including a solar cell and a bypass diode, said solar cell assembly comprising:

at least a first solar cell having a front surface, said front surface having at least a first recessed region;

a first solar cell contact formed on at least said first recessed region of said front surface;

a second solar cell contact formed on said front surface;

a bypass diode positioned at least partly in said first recessed region, said bypass diode having a first diode contact and a second diode contact;

a first interconnect coupling said first diode contact with said first solar cell contact; and

a second interconnect coupling said second diode contact to said second solar cell contact.

8. A solar cell assembly as defined in claim 7, said solar cell assembly further comprising:

a ceria-doped coverglass positioned over said solar cell; and

a substantially transparent adhesive positioned between said coverglass and said solar cell, said adhesive remaining substantially transparent when exposed to an AM0 space radiation environment.

9. A solar cell assembly as defined in claim 7, wherein said recessed region extends substantially downward to a wafer surface of said solar cell.

10. A solar cell assembly as defined in claim 7, wherein said solar cell is an GaInP₂/GaAs-type cell.

11. A solar cell assembly as defined in claim 7, wherein said bypass diode is formed from at least silicon.

12. A solar cell assembly as defined in claim 7, wherein said second solar cell contact is formed in said first recess.

14. A solar cell assembly as defined in claim 13, wherein at least one of said first and said second solar cells is formed from at least gallium arsenide and germanium.

15. A solar cell assembly as defined in claim 13, wherein said fifth interconnect is a U-shaped tab.

17. A solar cell assembly as defined in claim 16, wherein said second solar cell contact is formed on said first recessed region.

18. A solar cell assembly as defined in claim 16, wherein said recessed region has an area of no more than 0.22 inches².

19. A solar cell assembly as defined in claim 16, wherein said second contact is formed from at least Ti/Pd/Ag metal.

20. A solar cell assembly as defined in claim 16, said solar cell assembly further comprising an antireflection layer overlying at least a portion of said front surface.

21. A solar cell assembly as defined in claim 16, said solar cell assembly further comprising at least a first bypass diode positioned in said recessed region.

22. A solar cell assembly as defined in claim 21, wherein said first solar cell contact is coupled to a solar cell anode, said second solar cell contact is coupled to a solar cell cathode, and said bypass diode has at least a first diode contact coupled to a diode anode and a second diode contact coupled to a diode cathode.

23. A solar cell assembly as defined in claim 22, wherein said first solar cell contact is electrically coupled to said second diode contact, and said second solar cell contact is electrically coupled to said first diode contact.

24. A solar cell assembly as defined in claim 16, said solar cell assembly further comprising a substantially transparent cover overlying at least a portion of said solar cell.

27. The method of interconnecting a solar cell with a bypass diode as defined in claim 26, wherein said selected layer is an interface layer.

28. The method of interconnecting a solar cell with a diode as defined in claim 26, wherein said forming act includes the act of etching down to a bottom-most layer.

30. A solar cell assembly as defined in claim 29, wherein said selected layer is an interface between a first cell layer and a second cell layer.

31. A solar cell assembly as defined in claim 29, wherein said selected layer is a bottom-most layer.

13. A solar cell array including at least two solar cell assemblies, said solar cell array comprising:

a first solar cell assembly, said first solar cell assembly including;

a first solar cell having a first surface, said first surface having at least a first recessed region;

a first solar cell contact formed on at least said first recessed region of said first surface;

a second solar cell contact formed on said first surface;

a first bypass diode positioned on said front surface, said first bypass diode having a first diode contact and a second diode contact;

a first interconnect coupling said first diode contact with said first solar cell contact;

a second interconnect coupling said second diode contact to said second solar cell contact;

a second solar cell assembly, said second solar cell assembly including;

a second solar cell having a second surface, said second surface having at least a second recessed region;

a third solar cell contact formed on at least said second recessed region of said second surface;

a fourth solar cell contact formed on said second surface;

a second bypass diode positioned on said second surface, said second bypass diode having a third diode contact and a fourth diode contact;

a third interconnect coupling said third diode contact with said third solar cell contact; and

a fourth interconnect coupling said fourth diode contact to said fourth solar cell contact;

and

a top-level interconnect electrically coupling said first solar cell assembly and said second solar cell assembly.

16. A solar cell assembly including a solar cell, said solar cell assembly comprising:

at least a first solar cell having a front surface, said front surface having at least a first recessed region shaped to receive a diode;

a first solar cell contact formed on at least said first recessed region of said front surface, said first solar cell contact configured to be electrically coupled to a first diode contact; and

a second solar cell contact formed on said front surface, said second solar cell contact configured to be electrically coupled to a second diode contact.

25. A solar cell assembly comprising:

at least one means for converting solar energy into electrical energy having a first face, said first face having at least one means for receiving a means for protecting said at least one means for converting solar energy;

a first means for electrically coupling to said means for converting solar energy, said first means for electrically coupling located on said means for receiving;

a second means for electrically coupling to said means for converting solar energy, said second means for electrically coupling located on said first face;

a means for protecting said means for converting solar energy located on said means for receiving, said means for protecting having a third means for electrically coupling to said means for protecting and a fourth means for electrically coupling to said means for protecting;

a means for electrically interconnecting said first means for electrically coupling to said third means for electrically coupling;

a means for electrically interconnecting said second means for electrically coupling to said fourth means for electrically coupling; and

a means for covering at least a portion of said means for converting solar energy into electrical energy.

26. A method of interconnecting a solar cell with a bypass diode, said method comprising the acts of:

forming at least a first recess through said front surface of said solar cell to at least a first selected cell layer;

positioning at least a first bypass diode on said solar cell front surface; and

interconnecting said bypass diode to said first selected layer via said recess.

29. A solar cell assembly including a solar cell and a bypass diode, said solar cell assembly comprising:

at least a first solar cell having a front surface, said front surface having at least a first recessed region extending down to at least a first selected layer;

a solar cell contact formed on at least a portion of said front surface;

a diode positioned on said front surface, said diode having a first diode contact and a second diode contact;

a first interconnect coupling said first diode contact with said solar cell contact; and

a second interconnect coupling said second diode contact to said selected first layer via said recess.