Screen Printing Technology for Energy Devices

Abstract: The technical application of screen and stencil printing has been state of the art for decades. As part of the subtractive production process of printed circuit boards, for instance, screen and stencil printing play an important role. With the end of the 20th century, another field has opened up with organic electronics. Since then, more and more functional layers have been produced using printing methods. Printed electronics devices offer properties that give almost every freedom to the creativity of product development. Flexibility, low weight, use of non-toxic materials, simple disposal and an enormous number of units due to the production process are some of the prominent keywords associated with this field.Screen printing is a widely used process in printed electronics, as this process is very flexible with regard to the materials that can be used. In addition, a minimum resolution of approximately 30 µm is sufficiently high. The ink film thickness, which can be controlled over a wide range, is an extremely important advantage of the process. Depending on the viscosity, layer thicknesses of several hundred nanometres up to several hundred micrometres can be realised.The conversion and storage of energy became an increasingly important topic in recent years. Since regenerative energy sources, such as photovoltaics or wind energy, often supply energy intermittently, appropriate storage systems must be available. This applies to large installations for the power supply of society, but also in the context of autarkic sensors, such as those used in the Internet of Things or domestic/industrial automation. A combination of micro-energy converters and energy storage devices is an adequate concept for providing energy for such applications.In this thesis the above mentioned keywords are addressed and the feasibility of printed thermoelectric energy converters and supercapacitors as energy storage devices are investigated. The efficiency of thermoelectric generators (TEG) is low, but in industrial environments, for example, a large amount of unused low temperature heat energy can be found. If the production costs of TEGs are low, conversion of this unused heat energy can contribute to increasing system efficiency.Additionally, printing of supercapacitor energy storage devices increases the usability of the TEG. It is appropriate to use both components as complementary parts in an energy system.