Paper TF+EM+NS+SS-ThM4
Development of Low-Cost, Crack-Tolerant Metallization Using Screen Printing for Increased Durability of Silicon Solar Cell Modules
Thursday, October 24, 2019, 9:00 am, Room A122-123
| Session: |
Thin Films for Energy Harvesting and Conversion |
| Presenter: |
Sang M. Han, University of New Mexico |
| Authors: |
O.K. Abudayyeh, Osazda Energy
A. Chavez, University of New Mexico
J. Chavez, Osazda Energy
S.M. Han, University of New Mexico
F. Zimbardi, Georgia Institute of Technology
B. Rounsaville, Georgia Institute of Technology
V. Upadhyaya, Georgia Institute of Technology
A. Rohatgi, Georgia Institute of Technology
B. McDanold, National Renewable Energy Laboratory
T. Silverman, National Renewable Energy Laboratory
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| Correspondent: |
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One of the ways to reduce the cost of solar electricity to 3¢/kWh, thus reaching parity with fossil-fuel-based generation, is to reduce the degradation rate of solar modules and extend their lifetime well beyond 30 years. The extended module lifetime in turn can positively influence the financial model and the bankability of utility-scale PV projects. Today, the highest-risk-priority solar module degradation mechanism is what is known as hot spots, often induced by cell cracks. In order to address this degradation mechanism, we make use of low-cost, multi-walled carbon nanotubes embedded in commercial screen-printable silver pastes, also known as metal matrix composites. When the carbon nanotubes are properly functionalized and appropriately incorporated into commercial silver pastes, the resulting metal contacts on solar cells, after screen-printing and firing, show exceptional fracture toughness. These composite metal contacts possess increased ductility, electrical gap-bridging capability up to 50 µm, and “self-healing” to regain electrical continuity even after cycles of complete electrical failure under extreme strain [1]. Accelerated thermal cycling tests on mini-modules constructed from aluminum back surface field (Al-BSF) cells show a slower degradation rate for the cells integrated with the composite grid fingers and busbars for the front surface metallization compared to the cells with conventional metallization.[1] O. K. Abudayyeh, A. Chavez, J. Chavez, S. M. Han, F. Zimbardi, B. Rounsaville, V. Upadhyaya, A. Rohatgi, B. McDanold, T. J. Silverman, and N. Bosco, in "Low-Cost Advanced Metallization to Reduce Cell-Crack-Induced Degradation for Increased Module Reliability," 2019 NREL PV Reliability Workshop, Lakewood, CO, 2019.