Method and Manufacturing Thin Film Photovoltaic Modules

• US 20080105303A1
• Filed: 08/08/2007
• Published: 05/08/2008
• Est. Priority Date: 01/03/2003
• Status: Abandoned Application

• Current Assignee: BP Corporation North America Incorporated (BP PLC)
• Original Assignee: BP Corporation North America Incorporated (BP PLC)
• Inventors: Liu, Shengzhong, Oswald, Robert
• Application Number:
  US11/835,474
• Publication Number:
  US 20080105303A1
• Time in Patent Office: Days
• US Class Current: 136/261
• CPC Class Codes: B23K 26/03 Observing, e.g. monitoring, the workpiece
• CPC Class Codes: B23K 26/032 using optical means
• CPC Class Codes: B23K 26/0665 by beam condensation on the workpiece, e.g. for focusing
• CPC Class Codes: B23K 26/082 Scanning systems, i.e. devices involving movement of the laser beam relative to the laser head
• CPC Class Codes: H01L 31/046 PV modules composed of a plurality of thin film solar cells deposited on the same substrate
• CPC Class Codes: H01L 31/0463 characterised by special patterning methods to connect the PV cells in a module, e.g. laser cutting of the conductive or active layers
• CPC Class Codes: H01L 31/20 such devices or parts thereof comprising amorphous semiconductor materials
• CPC Class Codes: Y02E 10/50 Photovoltaic [PV] energy

Abstract

A method for manufacturing a thin film photovoltaic module comprising series connected cells, the cells comprising a front contact, a back contact and a photovoltaically active region positioned between the front and back contacts, the series connected cell being formed by scribing a front contact layer, a photovoltaically active layer and a back contact layer on a substrate, the method comprising laser scribing at least one of the front contact layer, the photovoltaically active layer or the back contact layer to form laser scribes using a laser beam scanned rapidly over the layer.

Claims

1. A method for manufacturing a thin film photovoltaic module comprising series connected cells, the cells comprising a front contact, a back contact and a photovoltaically active region positioned between the front and back contacts, the series connected cell being formed by scribing a front contact layer, a photovoltaically active layer and a back contact layer on a substrate, the method comprising laser scribing at least one of the front contact layer, the photovoltaically active layer or the back contact layer to form laser scribes using a laser beam scanned rapidly over the layer.

2. The method of claim 1 wherein the front contact layer, the photovoltaically active layer and the back contact layer are scribed using a laser beam scanned over the layer.

3. The method of claim 1 wherein the photovoltaically active layer and the photovoltaically active region comprises amorphous silicon.

4. The method of claim 1 wherein the photovoltaically active layer and photovoltaically active region comprises CdS/CdTe.

5. The method of claim 1 wherein the laser beam is scanned at a rate of about 1.0 to about 50 meters/second to form the scribes.

6. The method of claim 1 wherein the apparatus used to perform the laser scribing comprises a laser, a beam expander, a dynamic focusing unit and a scanner.

7. The method of claim 6 wherein the scanner comprises X-Y mirrors operated by a galvanometer.

8. The method of claim 6 further comprising optics for forming a linear laser beam shape.

9. The method of claim 8 wherein the laser is an Eximer laser.

10. The method of claim 1 wherein the shape of the laser beam scanned over the layer is linear.

19. Photovoltaic modules made by the method of claim 1.

20. The photovoltaic modules of claim 19 that are at least about 10 square feet in size.

21. The photovoltaic module of claim 20 comprising amorphous silicon.

22. The method of claim 1 wherein the laser beam used to form the scribes is the second harmonic of a solid state laser.

25. The method of claim 1 wherein the laser beam is a high reprate laser beam obtained by combining two or more laser beams of a lower reprate to form the high reprate laser beam.

11. (canceled)

12. A method of manufacturing a photovoltaic device on a substrate comprising the steps of:

(a) depositing a transparent and electrically conductive film on a substrate to form a front contact layer;

(b) laser scribing first grooves in the front contact layer with a rapidly scanning laser beam to form front contact segments on the substrate;

(c) depositing and forming a layer or layers of a semiconductor material on said front electrode segments, and filling the first grooves with the semiconductor material;

(d) laser scribing second grooves in the layer or layers of semiconductor material with a rapidly scanning laser beam at positions adjacent to the first grooves;

(e) depositing and forming a back contact layer comprising a metal on the layer or layers of semiconductor material, and filling the second grooves with the metal to form a series connection to connect the front electrode segments and the back contact layer; and

(f) laser scribing third grooves in the back contact layer with a rapidly scanning laser beam at positions adjacent to said second grooves with a laser beam.

13. The method of claim 12 wherein the semiconductor material comprises amorphous silicon.

14. The method of claim 12 wherein the scribing of the grooves is at about 1.0 to about 50 meters/second.

15. The method of claim 12 wherein the shape of the laser beam used to form the scribes is linear.

16. An apparatus for forming one or more laser scribes during the manufacture of thin-film photovoltaic devices comprising:

a laser, a beam expander, a means for focusing a laser beam, a scanner and a camera for viewing the photovoltaic device.

17. The apparatus of claim 16 wherein the scanner comprises X-Y mirrors.

18. The apparatus of claim 16 further comprising cylindrical optics to form a linear beam shape for forming the laser scribes.

23. The apparatus of claim 16 wherein the means for focusing a laser beam is a dynamic focusing unit.

24. An apparatus for forming one or more laser scribes during the manufacture of a thin-film photovoltaic device comprising:

a laser, a beam expander, a means for focusing the laser, a scanner and optics for forming a linear beam shape for the laser beam.

26. An apparatus for producing a high reprate laser comprising:

at least two lower reprate laser cavities each producing a laser beam having a corresponding reprate, a means for controlling the laser cavities so that pulses of the lasers are separated from each other, and a means for combining the laser beams so that the combined beam has a reprate higher than the reprate of any of the lower reprate laser cavities.

27. The apparatus of claim 26 wherein the means for combining the laser beams comprises a laser beam separator/combiner.

28. The apparatus of claim 27 further comprising a waveplate.

29. A method for producing a high reprate laser beam comprising combining at least two laser beams after shifting the pulse of at least one of the laser beams, to form a combined laser beam having a reprate higher than any of the laser beams before combining.