Page 71 - Advances in Renewable Energies and Power Technologies

44 CHAPTER 1 Solar Cells and Arrays: Principles, Analysis, and Design

Acrylic sheet
Rubber gasket
SC SC
Fiber
Rubber gasket
Adhesive Al sheet
Solder contact Silver paste spot
A1 Frame Copper stripe bonded by silicon adhesive
FIGURE 1.38
Flat plate module construction.

relatively soft allowing the bonding of materials with appreciably different linear
thermal coefficients.
This structure is characterized by the following:
1. The wind forces do not reach the solar cells because the upper and the lower
sheets will reflect the wind and act as barrier or wind shield.
2. Because there is no mechanical requirements on the substrate carryingthe cells, it
could be made of thin sheet; therefore, saving in weight and cost.
3. The substrate can be made of material with easy mechanical processing such as
fiber, wood, acrylic, printed boards, and plastic sheets. This makes the assembly
of the solar cells on the substrate easy.
4. One of the possible ways to assemble the cells is to bond first the interconnect
wire strips to the substrate using a glue material, then the solar cells are bonded
to the wires from the back side by conducting silver paste. Finally, the wires are
soldered to the front of the next solar cell as shown in Fig. 1.39.
One can carry out the first step by using printed circuit boards. If no silver paste is
available, one can use the through hole assembly process [36]. One uses soft adhe-
sives for die bond and wire attach to relieve the transfer of stresses between the mul-
tilayers. The detailed steps of the fabrication of this module are given in [35].

5.8 THE GLASSING FACTOR OF THE MODULE

The transparent module cover affects the incident solar radiation to the underly-
ing solar cells. It reflects some incident solar radiation and absorbs another

SC SC SC SC Silver paste spot
Copper stripe
Silicon
Adhesive
Fiber sheet
FIGURE 1.39
The assembly of the solar cells (SC) and the interconnected wires to a fiber substrate
sheet.