Temporary Field Assisted Passivation For Testing Of Partially Processed Photovoltaic Solar Cells
A method for electrical testing of a back contact solar cell applies a first side of a temporary passivation sheet to a frontside of a back contact solar cell, the first side of the temporary passivation sheet comprising at least a transparent dielectric layer. The temporary passivation sheet having a second side opposite the first side and comprising at least a transparent conductive coating. A voltage is applied between the transparent conductive coating and base metallization of the back contact solar cell. The frontside of the back contact solar cell is illuminated through the transparent conductive coating and the transparent dielectric layer. Electrical testing is performed on the back contact solar cell. The temporary passivation sheet is removed from the frontside of the back contact solar cell.
1 . A method for electrical testing of a back contact solar cell, comprising:
applying a first side of a temporary passivation sheet to a frontside of a back contact solar cell, said first side of said temporary passivation sheet comprising at least a transparent dielectric layer, said temporary passivation sheet having a second side opposite said first side and comprising at least a transparent conductive coating;
applying a voltage between said transparent conductive coating and base metallization of said back contact solar cell;
illuminating said frontside of said back contact solar cell through said transparent conductive coating and said transparent dielectric layer;
performing electrical testing on said back contact solar cell; and
removing said temporary passivation sheet from said frontside of said back contact solar cell.
2 . The method for measuring an electric parametric value from a back contact solar cell of claim 1 , wherein said temporary passivation sheet comprises a transparent dielectric layer having a thickness less than 50 μm and said transparent conductive oxide is indium tin oxide.
3 . The method for measuring an electric parametric value from a back contact solar cell of claim 1 , wherein said voltage is in the range of hundreds to thousands of volts.
4 . The method for measuring an electric parametric value from a back contact solar cell of claim 1 , wherein said electrical testing measures short circuit current, open circuit voltage, and fill factor of said solar cell.
5 . A back contact solar cell test structure, comprising:
a back contact solar cell comprising:
a solar cell substrate having a light receiving frontside and a backside, said backside comprising base and emitter regions;
base metallization and emitter metallization on said substrate backside, said base metallization contacting said base regions and said emitter metallization contacting said emitter regions;
a temporary passivation sheet having at least a transparent dielectric and a transparent conductive coating;
an electrical power supply electrically connected to said transparent conductive coating and electrically connected to said solar cell substrate by said base metallization; and
a solar cell electrical tester electrically connected to said base metallization and said emitter metallization.
6 . The back contact solar cell test structure of claim 5 , wherein said transparent dielectric is dielectric film having a thickness of less than or equal to approximately 50 μm.
7 . The back contact solar cell test structure of claim 5 , wherein said transparent dielectric is dielectric film having a thickness of less than or equal to approximately 25 μm.
8 . The back contact solar cell test structure of claim 5 , wherein said transparent dielectric is dielectric film having a thickness of less than or equal to approximately 12.5 μm.
9 . The back contact solar cell test structure of claim 5 , wherein said transparent conductive coating is a transparent conductive oxide.
10 . The back contact solar cell test structure of claim 9 , wherein said transparent conductive oxide is indium tin oxide.
11 . The back contact solar cell test structure of claim 5 , wherein said temporary passivation sheet comprises a transparent dielectric layer having a thickness less than 50 μm and said transparent conductive coating is indium tin oxide.
12 . The back contact solar cell test structure of claim 5 , wherein said solar cell electrical tester is a solar cell IV tester with a solar light simulator.
13 . The back contact solar cell test structure of claim 5 , further comprising a metal frame around the periphery of said temporary passivation sheet and electrically contacting said transparent conductive coating.
14 . A solar cell electrical tester for electrical testing of partially processed solar cells, comprising:
a solar simulator illumination source;
a temporary passivation sheet having at least a transparent dielectric and a transparent conductive coating;
a chuck having base electrical probes and emitter electrical probes;
an electrical power supply electrically connected to said transparent conductive coating and said base electrical probes; and
a solar cell electrical tester electrically connected to said base electrical probes and said emitter electrical probes.
15 . The back contact solar cell test structure of claim 14 , wherein said transparent conductive coating is a transparent conductive oxide.
16 . The back contact solar cell test structure of claim 15 , wherein said transparent conductive oxide is indium tin oxide.
17 . The back contact solar cell test structure of claim 14 , further comprising a metal frame around the periphery of said temporary passivation sheet and electrically contacting said transparent conductive coating.
18 . The back contact solar cell test structure of claim 14 , wherein said temporary passivation sheet comprises a transparent dielectric layer having a thickness less than 50 μm and said transparent conductive coating is indium tin oxide.
19 . The back contact solar cell test structure of claim 14 , wherein said solar cell electrical tester is a solar cell IV tester.