1.
H Schulte-Huxel; T Daschinger; B Min; T Brendemühl; R Brendel
Novel busbar design for screen-printed front side Al metallization of high-efficiency solar cell Artikel
In: Solar Energy Materials and Solar Cells, Bd. 264, S. 112601, 2024, ISSN: 0927-0248.
@article{Schulte-Huxel2024,
title = {Novel busbar design for screen-printed front side Al metallization of high-efficiency solar cell},
author = {H Schulte-Huxel and T Daschinger and B Min and T Brendemühl and R Brendel},
doi = {10.1016/j.solmat.2023.112601},
issn = {0927-0248},
year = {2024},
date = {2024-01-01},
urldate = {2024-01-01},
journal = {Solar Energy Materials and Solar Cells},
volume = {264},
pages = {112601},
abstract = {The need to reduce the silver consumption for future global PV production requires novel approaches for cell metallization and module integration. A screen-printed aluminum cell metallization on the front side could contribute here, but requires a redesign of the solder pads and busbars. A compromise between shading and resistive losses is needed. We investigate the inclusion of Ag solder pads in high-aspect-ratio Al finger grids on the front side of p-type back junction solar cells featuring passivating polysilicon on oxide (POLO) contacts on the rear side. In order to determine the optimal geometric dimensions of the solder pads, we characterize the resistance at the interface between the Ag solder pads and the Al finger grid in dependence on the size of the overlap between the two paste. A contact resistance of 285 mΩ is determined for 200 μm-narrow Al busbars and small solder pads of 750 μm in length. This would require tens of solder pads per busbar for acceptable power losses below 0.5 % coming along with significant shading. Therefore, a new metallization design is developed. We use narrow Ag busbars with a widened intersection to the Al fingers in order to reduce the contact resistance caused by the Ag–Al alloy. Thereby, the shading losses of the solderable busbars and pads are less than 1.5 %.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
The need to reduce the silver consumption for future global PV production requires novel approaches for cell metallization and module integration. A screen-printed aluminum cell metallization on the front side could contribute here, but requires a redesign of the solder pads and busbars. A compromise between shading and resistive losses is needed. We investigate the inclusion of Ag solder pads in high-aspect-ratio Al finger grids on the front side of p-type back junction solar cells featuring passivating polysilicon on oxide (POLO) contacts on the rear side. In order to determine the optimal geometric dimensions of the solder pads, we characterize the resistance at the interface between the Ag solder pads and the Al finger grid in dependence on the size of the overlap between the two paste. A contact resistance of 285 mΩ is determined for 200 μm-narrow Al busbars and small solder pads of 750 μm in length. This would require tens of solder pads per busbar for acceptable power losses below 0.5 % coming along with significant shading. Therefore, a new metallization design is developed. We use narrow Ag busbars with a widened intersection to the Al fingers in order to reduce the contact resistance caused by the Ag–Al alloy. Thereby, the shading losses of the solderable busbars and pads are less than 1.5 %.
2.
H Schulte-Huxel; S Blankemeyer; A Morlier; R Brendel; M Köntges
Interconnect-shingling: Maximizing the active module area with conventional module processes Artikel
In: Solar Energy Materials and Solar Cells, Bd. 200, S. 109991, 2019, ISSN: 0927-0248.
@article{Schulte-Huxel2019b,
title = {Interconnect-shingling: Maximizing the active module area with conventional module processes},
author = {H Schulte-Huxel and S Blankemeyer and A Morlier and R Brendel and M Köntges},
doi = {10.1016/j.solmat.2019.109991},
issn = {0927-0248},
year = {2019},
date = {2019-09-15},
journal = {Solar Energy Materials and Solar Cells},
volume = {200},
pages = {109991},
abstract = {We present a module fabrication process enabling gap-free interconnection of c-Si solar cells using solder-based interconnection technology with ribbons or wires. The interconnect-shingling process increases the module efficiency by avoiding the gaps between the solar cells. The process is applicable to bifacial cells and uses well-proven interconnection technologies. In contrast to previous adhesive-based shingled modules, the current transport is supported by interconnects, thus reducing the silver consumption for the cells’ metallization and avoiding cell overlap. We lay down the cells on structured encapsulant layers to reduce mechanical stress at the cell edges during lamination. Alternatively, the lamination process can be adapted to allow the encapsulant to reflow. This also results in a low pressure at sensitive cell parts. Both approaches avoid crack formation. We demonstrate the interconnect-shingling process with a proof-of-concept module having a aperture area efficiency of 22.1%. Applying 200 thermal cycles does not cause any crack formation.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
We present a module fabrication process enabling gap-free interconnection of c-Si solar cells using solder-based interconnection technology with ribbons or wires. The interconnect-shingling process increases the module efficiency by avoiding the gaps between the solar cells. The process is applicable to bifacial cells and uses well-proven interconnection technologies. In contrast to previous adhesive-based shingled modules, the current transport is supported by interconnects, thus reducing the silver consumption for the cells’ metallization and avoiding cell overlap. We lay down the cells on structured encapsulant layers to reduce mechanical stress at the cell edges during lamination. Alternatively, the lamination process can be adapted to allow the encapsulant to reflow. This also results in a low pressure at sensitive cell parts. Both approaches avoid crack formation. We demonstrate the interconnect-shingling process with a proof-of-concept module having a aperture area efficiency of 22.1%. Applying 200 thermal cycles does not cause any crack formation.