Electrical properties of the rear contact structure of MWT silicon solar cells

A review of concentrator silicon solar cells

“…Fellmeth et al made the metal wrap through (MWT) cell for concentration using industrial crystalline silicon solar cell manufacturing process, the efficiency was larger than 20% under 5-12 suns [78]. The MWT cell was a combination of bifacial contact cell and back contact cell, the grids were made on the front surface of the cell, but the bus-bars were made on the back surface and connected to grids through the roles in the cell to decrease the shading losses [57,[78][79][80], the structure of the MWT cell drew by Lohmüller et al is shown in Fig. 11 …”

“…The structure of the MWT cell drew by Lohmüller et al[80].Reprinted from Solar Energy Materials and Solar Cells, 137, Lohmüller E, Thanasa M, Thaidigsmann B, Clement F, Biro D, Electrical properties of the rear contact structure of MWT silicon solar cells, 293-302, Copyright (2015), with permission from Elsevier.…”

“…[80].Ebert et al made a concentrating module based on these MWT cells; its efficiency reached 19.2% under 9.9 suns [81]. Fellmeth et al also tried to use PERC structure in MWT cell, the highest efficiency was 19.8% under 3 suns, the additional series resistance caused by local metal contact constrained its use under higher concentration ratio[57].…”

Reverse Bias Behavior of Diffused and Screen-Printed n-Type Cz-Si Solar Cells

“…1 b,c) was metallized by a two-step screen printing process. First, the finger structures were printed with a fire-through silver paste, followed by the simultaneous printing of the external p-type and n-type contacts, as well as the vias with a non-fire-through silver via paste [2]. The front grid, with three thin pseudo-busbars, was screen-printed with a silver-aluminum paste.…”

“…In order to avoid shunting, the via paste must not form an electrically conductive contact to the adjacent n-type-doped region under forward bias. In previous experiments, special test structures have been used to examine the influence of reverse biasing on the electrical contact insulation between BSF and external p-type contacts [2]. A strong degradation of the electrical contact insulation was observed for the rear contact setup corresponding to cell MWT-B.…”