Backplane reinforcement and interconnects for solar cells
Fabrication methods and structures relating to backplanes for back contact solar cells that provide for solar cell substrate reinforcement and electrical interconnects are described. The method comprises depositing an interdigitated pattern of base electrodes and emitter electrodes on a backside surface of a semiconductor substrate, forming electrically conductive emitter plugs and base plugs on the interdigitated pattern, and attaching a backplane having a second interdigitated pattern of base electrodes and emitter electrodes at the conductive emitter and base plugs to form electrical interconnects.
1. A back contact crystalline semiconductor solar cell, comprising:
a crystalline semiconductor substrate, said substrate comprising a light capturing frontside surface and a backside surface for forming emitter and base contacts;
a first electrically conductive interconnect layer having an interdigitated pattern of emitter electrodes and base electrodes on said backside surface of said crystalline substrate, said first electrically conductive interconnect layer having a thickness less than approximately 10 microns;
electrically conductive emitter plugs and base plugs forming electrical connections to said emitter and base electrodes; and
a backplane attached to said backside surface of said crystalline substrate by said electrically conductive emitter plugs and base plugs and providing permanent crystalline substrate reinforcement and high-conductivity solar cell interconnects, said backplane comprising:
a second electrically conductive interconnect layer providing high-conductivity cell interconnects connected to said first electrically conductive interconnect layer by said electrically conductive emitter and base plugs, said second electrically conductive interconnect layer having an interdigitated pattern of emitter electrodes and base electrodes and a metallic layer thickness in the range of approximately 100 to 1000 microns; and
a backplane plate attached to said second electrically conductive interconnect layer, said backplane plate having through holes exposing emitter and base metal contacts and providing connections to solar cell base and emitter regions using an electrically conductive material for solar cell interconnection.
2. The back contact solar cell of claim 1 , further comprising a dielectric adhesive layer covering said first electrically conductive interconnect layer and exposing said electrically conductive emitter plugs and base plugs.
3. The back contact solar cell of claim 1 , wherein said crystalline semiconductor substrate has a thickness less than 100 microns.
4. The back contact solar cell of claim 1 , wherein said first electrically conductive interconnect layer has an interdigitated pattern with busbars and emitter electrodes and base electrodes.
5. The back contact solar cell of claim 1 , wherein said second electrically conductive interconnect layer has an interdigitated pattern with busbars and emitter electrodes and base electrodes.
6. The back contact solar cell of claim 1 , wherein said second electrically conductive interconnect layer has extended ends for forming wrap-around backside metal interconnects on said solar cell.
7. The back contact solar cell of claim 1 , wherein said second electrically conductive interconnect layer aligns substantially parallel to said first electrically conductive interconnect layer.
8. The back contact solar cell of claim 1 , wherein said second electrically conductive interconnect layer aligns substantially orthogonal to said first electrically conductive interconnect layer.
9. The back contact solar cell of claim 1 , wherein said emitter electrodes and base electrodes of second electrically conductive interconnect layer have deformed regions.
10. The back contact solar cell of claim 1 , wherein said second electrically conductive interconnect layer is aluminum foil.
11. A back contact crystalline semiconductor solar cell comprising:
a crystalline semiconductor substrate, said substrate comprising a light capturing frontside surface and a backside surface for forming emitter and base contacts;
a first electrically conductive interconnect layer having an interdigitated pattern of emitter electrodes and base electrodes on said backside surface of said crystalline substrate, said first electrically conductive interconnect layer having a thickness less than approximately 10 microns;
electrically conductive emitter plugs and base plugs forming electrical connections to said emitter and base electrodes; and
a backplane attached to said backside surface of said crystalline substrate by said electrically conductive emitter plugs and base plugs and providing permanent crystalline substrate reinforcement and high-conductivity solar cell interconnects, said backplane comprising:
a second electrically conductive interconnect layer providing high-conductivity cell interconnects connected to said first electrically conductive interconnect layer by said electrically conductive emitter and base plugs, said second electrically conductive interconnect layer having an interdigitated pattern of emitter electrodes and base electrodes and wherein said second electrically conductive interconnect layer has a thickness in the range of 25-250 microns; and
a backplane plate attached to said second electrically conductive interconnect layer, said backplane plate having through holes exposing emitter and base metal contacts and providing connections to solar cell base and emitter regions using an electrically conductive material for solar cell interconnection.