Abstract
Cracks in crystalline silicon solar cells can lead to substantial power loss. While the cells' metal contacts can initially bridge these cracks and maintain electrical connections, the bridges are damaged by mechanical loads, including those due to temperature changes. We investigated the metallization bridges that form over cracks in encapsulated silicon solar cells. Microscopic characterization showed that the crack in the silicon can immediately propagate through the metal grid, but the grid can maintain electrical contact once the load is removed. We also quantified the movement of the cell fragments separated by a crack as a function of temperature. Cell fragments are free to move diagonally and to rotate, so the change in gap across the crack during a temperature change varies along the length of the crack. In one sample, we showed that a 10C temperature change, causing a 2 μm increase in the separation of cell fragments, was sufficient to cause a reversible electrical disconnection of metallization bridging a crack.
Original language | American English |
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Pages | 1517-1520 |
Number of pages | 4 |
DOIs | |
State | Published - Jun 2019 |
Event | 46th IEEE Photovoltaic Specialists Conference, PVSC 2019 - Chicago, United States Duration: 16 Jun 2019 → 21 Jun 2019 |
Conference
Conference | 46th IEEE Photovoltaic Specialists Conference, PVSC 2019 |
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Country/Territory | United States |
City | Chicago |
Period | 16/06/19 → 21/06/19 |
Bibliographical note
Publisher Copyright:© 2019 IEEE.
NREL Publication Number
- NREL/CP-5K00-73200
Keywords
- image processing
- materials reliability
- materials testing
- metallization
- photovoltaic cells