Module fabrication of solar cells with low resistivity electrodes

1. A solar module, comprising:

a plurality of connected solar cells, wherein a respective solar cell comprises:

a multi-layer semiconductor structure that has a first-polarity surface and a second-polarity surface, wherein the second polarity is opposite to the first polarity;

a first electrode on the first-polarity surface; and

a second electrode on the second-polarity surface;

wherein the first and second electrodes each comprise a plurality of finger lines and a busbar coupled to the finger lines; and

wherein the first-polarity surface and second-polarity surface each have only an area near one edge covered by the busbar.

2. The solar module of claim 1 , wherein two adjacent solar cells are connected to each other by a stringing ribbon soldered to a first busbar on the first-polarity surface of a first solar cell and a second busbar on the second-polarity surface of an adjacent solar cell, and wherein a width of the stringing ribbon is substantially similar to a width of the busbars.

3. The solar module of claim 1 , wherein the busbars on the first-polarity surface and second-polarity surface of the solar cell are located near opposite edges.

4. The solar module of claim 3 , wherein two adjacent solar cells are connected by a metal tab soldered to a first busbar on the first-polarity surface of a first solar cell and a second busbar on the second-polarity surface of the adjacent solar cell, wherein a width of the metal tab is substantially similar to a length of the first and second busbars.

5. The solar module of claim 4 , wherein the first-polarity surface of the first solar cell and the second-polarity surface of the adjacent solar cell are facing different directions.

6. The solar module of claim 4 , wherein the first-polarity surface of the first solar cell and the second-polarity surface of the adjacent solar cell are facing a same direction.

7. The solar module of claim 4 , wherein a plurality of solar cells are coupled by metal tabs into a string, and wherein a plurality of strings are coupled electrically in series or in parallel.

8. The solar module of claim 4 , wherein a length of the metal tab is between 3 and 12 mm.

9. The solar module of claim 3 , wherein two adjacent solar cells are coupled together by overlapping edges of the two adjacent solar cells, wherein the two adjacent solar cells are overlapped in such a way that a first busbar on the first-polarity surface of a first solar cell is in contact with a second busbar on the second-polarity surface of an adjacent solar cell, thereby facilitating a serial connection between the two adjacent solar cells.

10. The solar module of claim 9 , wherein a plurality of solar cells are coupled by overlapping edges to form a string, and wherein a plurality of strings are coupled electrically in series or in parallel.

11. The solar module of claim 1 , wherein the multi-layer semiconductor structure comprises:

a base layer;

a front- or back-side emitter layer; and

a back or front surface field layer.

12. The solar module of claim 11 , wherein the multi-layer semiconductor structure comprises a quantum tunneling barrier (QTB) layer positioned at both sides of the base layer.

13. The solar module of claim 1 , wherein the first and second electrodes each comprise at least an electroplated Cu layer.

14. The solar module of claim 1 , wherein a width of the busbar is between 0.5 and 3 mm.

15. The solar module of claim 1 , further comprising a plurality of maximum power point tracking devices, wherein a respective maximum power point tracking device is coupled to an individual solar cell, thereby facilitating cell-level maximum power point tracking.

16. The solar module of claim 1 , further comprising a plurality of maximum power point tracking devices, wherein a respective maximum power point tracking device is coupled to a string of solar cells, thereby facilitating string-level maximum power point tracking.

17. The solar module of claim 1 , further comprising a front-side cover and a back-side cover, wherein both the front- and back-side covers are transparent to facilitate bifacial configuration of the solar module.

18. The solar module of claim 1 , wherein the plurality of solar cells includes at least one of:

a 5-inch solar cell;

a 6-inch solar cell; and

a ⅛, ⅙, ¼, ⅓, or ½ of a 5-inch or a 6-inch solar cell.

19. A solar cell coupling system, comprising:

a first solar cell and a second solar cell, wherein a respective solar cell comprises a first electrode on a first-polarity surface and a second electrode on a second-polarity surface, wherein a respective electrode comprises a plurality of finger lines and a busbar coupled to the finger lines, the busbar being positioned near an edge of the respective solar cell, and wherein the first-polarity surface and second-polarity surface each have only an area covered by the busbar; and

a metal tab connecting the first electrode of the first solar cell and the second electrode of the second solar cell.

20. A solar cell coupling system, comprising:

a first solar cell and a second solar cell connected to each other, wherein a respective solar cell comprises a first electrode on a first-polarity surface and a second electrode on a second-polarity surface, wherein a respective electrode comprises a plurality of finger lines and a busbar coupled to the finger lines, the busbar being positioned near an edge of the respective solar cell, and wherein the first-polarity surface and second-polarity surface each have only an area covered by the busbar;

wherein an edge of the first solar cell overlaps with an edge of the second solar cell such that busbar on the first-polarity surface of the first solar cell is in contact with a busbar on the second-polarity surface of the second solar cell.