Module fabrication of solar cells with low resistivity electrodes

• US 9,496,427 B2
• Filed: 12/07/2015
• Issued: 11/15/2016
• Est. Priority Date: 01/11/2013
• Status: Active Grant

• Current Assignee: Tesla Inc.
• Original Assignee: SolarCity Corporation (Tesla Inc.)
• Inventors: Heng, Jiunn Benjamin, Fu, Jianming, Xu, Zheng, Yang, Bobby
• Primary Examiner(s): LEONG, SUSAN DANG
• Application Number:
  US14/961,639
• Publication Number:
  US 20160087120A1
• Time in Patent Office: 344 Days
• US Class Current: 1/1
• CPC Class Codes: H01L 31/0201 comprising specially adapted module bus-bar structures
• CPC Class Codes: H01L 31/02021 for solar cells electrical connection means, e.g. junction boxes, specially adapted for structural association with photovoltaic modules H02S40/34
• CPC Class Codes: H01L 31/022425 for solar cells
• CPC Class Codes: H01L 31/022433 Particular geometry of the grid contacts
• CPC Class Codes: H01L 31/048 Encapsulation of modules
• CPC Class Codes: H01L 31/0488 Double glass encapsulation, e.g. photovoltaic cells arranged between front and rear glass sheets
• CPC Class Codes: H01L 31/0504 specially adapted for series or parallel connection of solar cells in a module
• CPC Class Codes: H01L 31/0684 double emitter cells, e.g. bifacial solar cells
• CPC Class Codes: H01L 31/0747 comprising a heterojunction of crystalline and amorphous materials, e.g. heterojunction with intrinsic thin layer
• CPC Class Codes: H01L 31/1876 Particular processes or apparatus for batch treatment of the devices
• CPC Class Codes: Y02E 10/547 Monocrystalline silicon PV cells

Abstract

One embodiment of the present invention provides a solar module. The solar module includes a front-side cover, a back-side cover, and a plurality of solar cells situated between the front- and back-side covers. A respective solar cell includes a multi-layer semiconductor structure, a front-side electrode situated above the multi-layer semiconductor structure, and a back-side electrode situated below the multi-layer semiconductor structure. Each of the front-side and the back-side electrodes comprises a metal grid. A respective metal grid comprises a plurality of finger lines and a single busbar coupled to the finger lines. The single busbar is configured to collect current from the finger lines.

Claims

1. A solar cell, comprising:

a multi-layer semiconductor structure;

a first electrode positioned on a first side of the multi-layer semiconductor structure; and

a second electrode positioned on a second side of the multi-layer semiconductor structure;

wherein the first side of the multi-layer semiconductor structure has no more than one edge substantially covered by a first busbar that is part of the first electrode; and

wherein the second side of the multi-layer semiconductor structure has an opposite edge substantially covered by a second busbar that is part of the second electrode.

2. The solar cell of claim 1, wherein the first electrode comprises a number of finger lines.

3. The solar cell of claim 1, wherein the second electrode is continuous.

4. The solar cell of claim 1, wherein a respective electrode comprises an electroplated layer.

5. The solar cell of claim 4, wherein the electroplated layer comprises Cu.

6. The solar cell of claim 4, wherein the electroplated layer is coated with Ag or Sn.

7. The solar cell of claim 1, wherein a respective electrode comprises a seed layer formed with a physical vapor deposition technique.

8. The solar cell of claim 7, wherein the seed layer comprises Cu or Ni.

9. The solar cell of claim 1, wherein a width of a respective busbar is between 0.5 and 3 mm.

10. A solar module, comprising:

a first cover;

a second cover; and

a plurality of solar cells positioned between the first and second covers, wherein a respective solar cell comprises;

a multi-layer semiconductor structure;

a first electrode positioned on a first side of the multi-layer semiconductor structure; and

a second electrode positioned on a second side of the multi-layer semiconductor structure;

wherein the first side of the multi-layer semiconductor structure has no more than one edge substantially covered by a first busbar that is part of the first electrode; and

wherein the second side of the multi-layer semiconductor structure has an opposite edge substantially covered by a second busbar that is part of the second electrode.

11. The solar module of claim 10, wherein two adjacent solar cells are coupled together by electrically connecting the busbar on a back surface of one of the two adjacent solar cells with the busbar on a front surface of the other one of the two adjacent solar cells.

12. The solar module of claim 10, wherein two adjacent solar cells are coupled together by electrically connecting a busbar at an edge of a solar cell and a busbar at an adjacent edge of an adjacent solar cell.

13. The solar module of claim 12, wherein a length of the electrical connection is substantially similar to a length of the first busbar.

14. The solar module of claim 10, wherein the first electrode comprises a number of finger lines.

15. The solar module of claim 10, wherein the second electrode is continuous.

16. The solar module of claim 10, wherein a respective electrode comprises an electroplated layer.

17. The solar module of claim 16, wherein the electroplated layer comprises Cu.

18. The solar module of claim 16, wherein the electroplated layer is coated with Ag or Sn.

19. The solar module of claim 10, wherein a respective electrode comprises a seed layer formed with a physical vapor deposition technique.

20. The solar module of claim 19, wherein the seed layer comprises Cu or Ni.