Radially arranged metal contact fingers for solar cells

Patent metadata

Field	Value
Publication number	US-9306085-B2
Application number	US-201213591641-A
Country	US
Kind code	B2
Filing date	Aug 22, 2012
Priority date	Aug 22, 2012
Publication date	Apr 5, 2016
Grant date	Apr 5, 2016

Abstract

A solar cell includes negative metal contact fingers and positive metal contact fingers. The negative metal contact fingers are interdigitated with the positive metal contact fingers. The metal contact fingers, both positive and negative, have a radial design where they radially extend to surround at least 25% of a perimeter of a corresponding contact pad. The metal contact fingers have bend points, which collectively form a radial pattern with a center point within the contact pad. Exactly two metal contact pads merge into a single leading metal contact pad that is wider than either of the exactly two metal contact pads.

First claim

What is claimed is:

1. A solar cell comprising:
a plurality of positive metal contact fingers, each of the positive metal contact fingers being coupled to one or more P-type diffusion regions on a backside of the solar cell, a front side of the solar cell facing the sun during normal operation to collect solar radiation;
a plurality of negative metal contact fingers, each of the negative metal contact fingers being coupled to one or more N-type diffusion regions on the backside of the solar cell, the negative metal contact fingers being interdigitated with the positive metal contact fingers; and
a negative contact pad at a corner of the solar cell and providing a surface on which an external interconnect lead may be attached to electrically couple to an N-type diffusion region by way of the negative metal contact fingers, the negative metal contact fingers having bend points that form a radial pattern having a center point within the negative contact pad, the negative metal contact fingers with the bend points radially extending to surround greater than 25% of a perimeter of the negative contact pad.

2. The solar cell of claim 1 further comprising a positive contact pad providing a surface on which an external interconnect lead may be attached to electrically coupled to a P-type diffusion region by way of the positive metal contact fingers, the positive metal contact fingers having bend points that form a radial pattern having a center point within the positive contact pad, the positive metal contact fingers radially extending to surround at least 25% of a perimeter of the positive contact pad.

3. The solar cell of claim 1 wherein exactly two negative metal contact fingers merge into a single leading negative metal contact finger that extends to the negative contact pad.

4. The solar cell of claim 3 wherein the single leading negative metal contact finger is wider than either of the exactly two negative metal contact fingers.

5. The solar cell of claim 1 wherein the negative metal contact fingers radially extend to surround between 25% and 75% of the perimeter of the negative contact pad.

6. The solar cell of claim 1 wherein the external interconnect lead is soldered onto the negative contact pad.

7. The solar cell of claim 1 wherein the solar cell is serially connected to another solar cell by a solar cell interconnect that electrically connects the negative contact pad to a positive contact pad of the other solar cell.

8. A solar cell comprising:
a plurality of negative metal contact fingers that are interdigitated with a plurality of positive metal contact fingers, each of the positive metal contact fingers being coupled to a corresponding P-type diffusion region of the solar cell, each of the negative metal contact fingers being coupled to a corresponding N-type diffusion region of the solar cell; and
a negative contact pad at a corner of the solar cell and electrically connected to the negative metal contact fingers but not to the positive metal contact fingers, the negative metal contact fingers being arranged with bend points to radially extend to surround greater than 25% of a perimeter of the negative contact pad.

9. The solar cell of claim 8 wherein the negative metal contact fingers with bend points radially extend to surround between 25% and 75% of a perimeter of the negative contact pad.

10. The solar cell of claim 8 further comprising a positive contact pad electrically connected to the positive metal contact fingers but not to the negative metal contact fingers, the positive metal contact fingers being arranged to radially extend to the positive contact pad.

11. The solar cell of claim 8 wherein exactly two negative metal contact fingers merge into a single leading negative metal contact finger that radially extends to the negative contact pad.

12. The solar cell of claim 8 wherein the single leading negative metal contact finger is wider than either of the exactly two negative metal contact fingers.

13. The solar cell of claim 8 wherein an external interconnect lead is soldered onto the negative contact pad.

14. The solar cell of claim 8 wherein the solar cell is serially connected to another solar cell by a solar cell interconnect that electrically connects the negative contact pad to a positive contact pad of the other solar cell.

15. A method of arranging metal contact fingers of a solar cell, the method comprising:
interdigitating a plurality of negative metal contact fingers with a plurality of positive metal contact fingers, the negative metal contact fingers being electrically connected to N-type diffusion regions on a backside of a solar cell, the positive metal contact fingers being electrically connected to P-type diffusion regions on the backside of the solar cell, the solar cell including a front side that faces the sun during normal operation;
arranging the negative metal contact fingers to have bend points that form a radial pattern having a center point within a negative contact pad at a corner of the solar cell, the negative metal contact fingers with the bend points radially extending to and surrounding greater than 25% of a perimeter of the negative contact pad; and
arranging exactly two negative metal contact fingers to merge into a single leading negative metal contact finger that extends to the negative contact pad.

16. The method of claim 15 further comprising:
arranging the positive metal contact fingers to have bend points that form a radial pattern having a center point within a positive contact pad of the solar cell, the positive metal contact fingers radially extending to and surrounding at least 25% of a perimeter of the positive contact pad.

17. The method of claim 15 , wherein the single leading negative metal contact finger is formed to be wider than either of the exactly two negative metal contact fingers.

18. The method of claim 15 further comprising:
soldering an external interconnect lead onto the negative contact pad.

19. The method of claim 15 further comprising serially-connecting the solar cell to another solar cell by a solar cell interconnect that electrically connects the negative contact pad to a positive contact pad of the other solar cell.

Assignees

• Westerberg Staffan
• Cousins Peter John
• Sunpower Corp

Inventors

• Westerberg Staffan
• Cousins Peter John

Classifications

• H10F77/215 Primary

  Geometries of grid contacts · CPC title

• H10F19/908

  for back-contact photovoltaic cells · CPC title

• H10F77/219 Primary

  Arrangements for electrodes of back-contact photovoltaic cells · CPC title

• H01L31/022433 Primary

  Electricity · mapped topic

• H01L31/022441

  Electricity · mapped topic