Movement of Cracked Silicon Solar Cells During Module Temperature Changes

Timothy Silverman, Ingrid Repins, Martin Bliss, Ali Abbas, Tom Betts, Michael Walls

Research output: Contribution to conferencePaperpeer-review

10 Scopus Citations

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 languageAmerican English
Pages1517-1520
Number of pages4
DOIs
StatePublished - Jun 2019
Event46th IEEE Photovoltaic Specialists Conference, PVSC 2019 - Chicago, United States
Duration: 16 Jun 201921 Jun 2019

Conference

Conference46th IEEE Photovoltaic Specialists Conference, PVSC 2019
Country/TerritoryUnited States
CityChicago
Period16/06/1921/06/19

Bibliographical note

Publisher Copyright:
© 2019 IEEE.

NREL Publication Number

  • NREL/CP-5K00-73200

Keywords

  • image processing
  • materials reliability
  • materials testing
  • metallization
  • photovoltaic cells

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