The considered scenario refers to an annual production of 500 000 modules with an average output power of 0.3 Wp per module at standard test conditions. Starting with this number of modules the investment into a production plant is worthwhile. If investment costs of 2.5 million Euro and a service life of the plant, which is shown in Fig. 7, of 10 years are assumed this will result in production costs of 5.12 Euro per module for the module production. The total module costs result from the sum of solar cell costs and the above mentioned module production costs. Additionally to the costs for the production plant the following costs were set: material unit costs: 0.70 EUR

manufacturing unit cost: 3.10 EUR

overhead unit costs: 0.13 EUR

The in Fig. 7 represented production plant consists of the dispensing and equipment unit, a hardening furnace for the SMD adhesive, a reflow oven to melt the solder paste, a roll laminator and an edge trimming unit. The dispensing and equipment unit can be taken over from the SMD manufacturing technology. It must control simultaneous dispensation and equipment, since after placing a solar cell their bus bar had to be covered with solder paste. The hardening and reflow oven are likewise standard production devices from the SMD technology. Only the roll laminator and the edge trimming unit are special devices for the production of solar modules. A roll laminator for module production is for example described in [HANOKA99]. For the edge trimming a water jet cutter is suitable.

Conclusions

The packaging and the contacting of high efficient solar cells was examined. In the first part of this work the function of electrically conductive adhesives in high efficient solar modules for device integration was tested. However no significant advantage resulted in relation to soldered contacts.

A new procedure for the shingle connection for solar cells on a printed circuit board was developed. The manufactured modules have a very small thickness of only 1.5 mm but are nevertheless mechanically so stable that they can be integrated into mobile devices. Additionally it is possible to use the economical manufacturing processes of the SMD manufacturing because of the use of printed circuit boards. By the use of PCBs the production of solar modules in an arbitrary form is possible. Almost no boundaries are set to the design of mobile devices. We have shown in our former work that it is possible to

integrate such high efficient modules in personal digital assistants (PDA) [Schmidhuber01 a]. With these solar powered PDAs a fully self-sufficient operation is possible.

Acknowledgement

We want to thank all colleges at Fraunhofer ISE for the support during this work.

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