Chapter 9
Solar Module Technology
Alessandro Virtuani
Abstract In a solar photovoltaic module, a number of individual solar cells are
electrically connected to increase their power output. Cells and interconnects are then
packaged in order to: (1) protect the electrical circuit from weathering, (2) provide
structural stability and protect the mechanical integrity of the cells, (3) isolate the
electrical circuit from the environment, protecting operators against electrical shocks.
In this chapter, we focus initially on the electrical layout of cells/modules and on the
typical sandwich and encapsulation structures used in solar module manufacturing,
by having a close look at the materials and processes used in the industry, and at
innovative concepts that are increasingly entering the market. We then review the
topics of performance, reliability and durability of solar modules and the related
subjects of industry qualification standards, service lifetime and warranties. A closer
look at failure modes experienced by modules in operation will be given in Chap. 10,
next up. In this chapter, our major focus will be on the dominant technology of
wafer-based crystalline silicon (c-Si) solar cells/modules. Peculiarities of module
technology for thin film modules will be reviewed briefly.
9.1 Electrical Layout of Solar Modules
9.1.1 Cell Interconnections
In a PV module, a number of individual solar cells are electrically connected to
increase their power output. In wafer-based crystalline solar (c-Si) solar cells, the
busbars present on the top of the cell (see Fig. 9.1) are connected directly to the rear
contact of the adjacent cell, by means of cell interconnect ribbons, generally tincoated copper ribbons (or silver-coated ones). This is shown in Fig. 9.2 for the case of
cells with 2-busbars (2BB); this figure shows as well how sub-strings are connected
by so-called string interconnects. Most often, the ribbons are soldered directly onto
A. Virtuani (B)
EPFL (PV-Lab), Neuchâtel, Switzerland
e-mail: alessandro.virtuani@epfl.ch
© Springer Nature Switzerland AG 2020
A. Shah (ed.), Solar Cells and Modules, Springer Series in Materials Science 301,
https://doi.org/10.1007/978-3-030-46487-5_9
219
Solar Module Technology
Alessandro Virtuani
Abstract In a solar photovoltaic module, a number of individual solar cells are
electrically connected to increase their power output. Cells and interconnects are then
packaged in order to: (1) protect the electrical circuit from weathering, (2) provide
structural stability and protect the mechanical integrity of the cells, (3) isolate the
electrical circuit from the environment, protecting operators against electrical shocks.
In this chapter, we focus initially on the electrical layout of cells/modules and on the
typical sandwich and encapsulation structures used in solar module manufacturing,
by having a close look at the materials and processes used in the industry, and at
innovative concepts that are increasingly entering the market. We then review the
topics of performance, reliability and durability of solar modules and the related
subjects of industry qualification standards, service lifetime and warranties. A closer
look at failure modes experienced by modules in operation will be given in Chap. 10,
next up. In this chapter, our major focus will be on the dominant technology of
wafer-based crystalline silicon (c-Si) solar cells/modules. Peculiarities of module
technology for thin film modules will be reviewed briefly.
9.1 Electrical Layout of Solar Modules
9.1.1 Cell Interconnections
In a PV module, a number of individual solar cells are electrically connected to
increase their power output. In wafer-based crystalline solar (c-Si) solar cells, the
busbars present on the top of the cell (see Fig. 9.1) are connected directly to the rear
contact of the adjacent cell, by means of cell interconnect ribbons, generally tincoated copper ribbons (or silver-coated ones). This is shown in Fig. 9.2 for the case of
cells with 2-busbars (2BB); this figure shows as well how sub-strings are connected
by so-called string interconnects. Most often, the ribbons are soldered directly onto
A. Virtuani (B)
EPFL (PV-Lab), Neuchâtel, Switzerland
e-mail: alessandro.virtuani@epfl.ch
© Springer Nature Switzerland AG 2020
A. Shah (ed.), Solar Cells and Modules, Springer Series in Materials Science 301,
https://doi.org/10.1007/978-3-030-46487-5_9
219