Wire-based metallization and stringing for solar cells
Wire-based metallization and stringing techniques for solar cells, and the resulting solar cells, modules, and equipment, are described. In an example, a substrate has a surface. A plurality of N-type and P-type semiconductor regions is disposed in or above the surface of the substrate. A conductive contact structure is disposed on the plurality of N-type and P-type semiconductor regions. The conductive contact structure includes a plurality of conductive wires, each conductive wire of the plurality of conductive wires essentially continuously bonded directly to a corresponding one of the N-type and P-type semiconductor regions.
1. A method of electrically coupling solar cells, comprising:
aligning conductive wires over back sides of adjacent solar cells, wherein the conductive wires are aligned substantially parallel to P-type and N-type doped diffusion regions of the solar cells;
bonding the conductive wires directly to the back side of each of the solar cells over the P-type and N-type doped diffusion regions using thermocompression bonding, wherein each conductive wire comprises a first portion having a substantially flat surface with microgrooves extending along a longest length of the conductive wire, and each conductive wire comprises a second portion that is substantially round and has a substantially smooth surface; and
cutting every other one of the conductive wires between each adjacent pair of the solar cells.
2. The method of claim 1 , wherein each conductive wire is parallel along a direction to form a one-dimensional layout.
3. The method of claim 1 , wherein each conductive wire has a flattened circular profile.
4. The method of claim 1 , wherein each conductive wire has a surface with microgrooves along a length of the conductive wire.
5. The method of claim 1 , wherein each solar cell has a substrate that is substantially rectangular, and wherein the corresponding P-type and N-type doped diffusion regions and the corresponding conductive wires are substantially parallel to an edge of the substrate.
6. The method of claim 5 , wherein the P-type and N-type doped diffusion regions are disposed in a back surface of the corresponding substrate, the back surface opposite an opposing light-receiving surface of the substrate.
7. The method of claim 5 , wherein the P-type and N-type doped diffusion regions are disposed above a back surface of the corresponding substrate, the back surface opposite an opposing light-receiving surface of the substrate.
8. A method of electrically coupling solar cells, comprising:
aligning conductive wires over back sides of adjacent solar cells, wherein the conductive wires are aligned substantially parallel to P-type and N-type doped diffusion regions of the solar cells;
bonding the conductive wires directly to the back side of each of the solar cells over the P-type and N-type doped diffusion regions using ultrasonic bonding, wherein each conductive wire comprises a first portion having a substantially flat surface with microgrooves extending along a longest length of the conductive wire, and each conductive wire comprises a second portion that is substantially round and has a substantially smooth surface; and
cutting every other one of the conductive wires between each adjacent pair of the solar cells.
9. The method of claim 8 , wherein each conductive wire is parallel along a direction to form a one-dimensional layout.
10. The method of claim 8 , wherein each conductive wire has a flattened circular profile.
11. The method of claim 8 , wherein each conductive wire has a surface with microgrooves along a length of the conductive wire.
12. The method of claim 8 , wherein each solar cell has a substrate that is substantially rectangular, and wherein the corresponding P-type and N-type doped diffusion regions and the corresponding conductive wires are substantially parallel to an edge of the substrate.
13. The method of claim 12 , wherein the P-type and N-type doped diffusion regions are disposed in a back surface of the corresponding substrate, the back surface opposite an opposing light-receiving surface of the substrate.
14. The method of claim 12 , wherein the P-type and N-type doped diffusion regions are disposed above a back surface of the corresponding substrate, the back surface opposite an opposing light-receiving surface of the substrate.
15. A method of electrically coupling solar cells, comprising:
aligning conductive wires over back sides of adjacent solar cells, wherein the conductive wires are aligned substantially parallel to P-type and N-type doped diffusion regions of the solar cells;
bonding the conductive wires directly to the back side of each of the solar cells over the P-type and N-type doped diffusion regions using thermosonic bonding, wherein each conductive wire comprises a first portion having a substantially flat surface with microgrooves extending along a longest length of the conductive wire, and each conductive wire comprises a second portion that is substantially round and has a substantially smooth surface; and
cutting every other one of the conductive wires between each adjacent pair of the solar cells.
16. The method of claim 15 , wherein each conductive wire is parallel along a direction to form a one-dimensional layout.
17. The method of claim 15 , wherein each conductive wire has a flattened circular profile.
18. The method of claim 15 , wherein each conductive wire has a surface with microgrooves along a length of the conductive wire.
19. The method of claim 15 , wherein each solar cell has a substrate that is substantially rectangular, and wherein the corresponding P-type and N-type doped diffusion regions and the corresponding conductive wires are substantially parallel to an edge of the substrate.
20. The method of claim 19 , wherein the P-type and N-type doped diffusion regions are disposed in a back surface of the corresponding substrate, the back surface opposite an opposing light-receiving surface of the substrate.
21. The method of claim 19 , wherein the P-type and N-type doped diffusion regions are disposed above a back surface of the corresponding substrate, the back surface opposite an opposing light-receiving surface of the substrate.