Showing papers by "Robert Hahn published in 2007"
01 Jan 2007
TL;DR: In this article, the authors proposed micro fuel cells (FCs) based on polymer electrolyte membranes (PEMs), which could be used as energy sources for applications in devices such as hearing aids, chip cards, wireless sensor networks and other small portable devices, thereby replacing Li-polymer batteries, button cells and zinc air batteries.
Abstract: Despite increasingly efficient components and low power technologies, the energy demands of portable electronic products such as next-generation mobile phones, wearable computers, autonomous sensors and microsystems will rise dramatically in the future due to their growing functionality. As improvements in battery technology have so far been limited to energy density increases of only a few percent per annum, over the past few years many R&D activities have concentrated on alternative forms of portable power supply. One of the most promising candidates is micro fuel cells (FCs) based on polymer electrolyte membranes (PEMs). They could be used as energy sources for applications in devices such as hearing aids, chip cards, wireless sensor networks and other small portable devices, thereby replacing Li-polymer batteries, button cells and zinc air batteries. Compared to batteries the environmental impact of fuel cells is much lower [1].
1 citations
01 Jan 2007
TL;DR: In this article, the authors proposed micro fuel cells (FCs) based on polymer electrolyte membranes (PEMs) as a battery replacement, but there are several challenges concerning fuel cells as battery replacement.
Abstract: Despite increasingly efficient components and low-power technologies, the energy demands of portable electronic products will rise dramatically in the future due to their growing functionality. As improvements in battery technology have so far been limited to energy density increases of only a few percent per annum, over the past few years many R&D activities have concentrated on alternative forms of portable power supply. One of the most promising candidates is micro fuel cells (FCs) based on polymer electrolyte membranes (PEMs) [1–3]. But there are several of challenges concerning fuel cells as a battery replacement:
1 citations
Patent•
31 Aug 2007
TL;DR: In this paper, a planar support and a pressure element are arranged around a membrane electrode unit and current conductor, such that the pressure element is mechanically tensioned by the curvature of the membrane.
Abstract: The invention relates to a fuel cell arrangement, a fuel cell system and a method for producing a fuel cell arrangement. According to the invention, the fuel cell arrangement comprises a planar support (1), a planar pressure element (3) and at least one planar fuel cell (2) of layered construction arranged between the support (1) and the pressure element (3), comprising at least one membrane electrode unit and current conductor, wherein support (1), fuel cell (2) and pressure element (3) are curved together such that at least the pressure element (3) is mechanically tensioned by the curvature such as to press against the support (1) as a result of the mechanical tension and the curvature of the fuel cell (2), the pressure element (3) being connected to the support (1) outside the region occupied by the fuel cell (2), in order to maintain the mechanical tension.
1 citations
Patent•
12 Jul 2007
TL;DR: In this paper, a Brennstoffzellensystem with einer Gaserzeugungseinrichtung (2, 3) and mit einer BER (1) zur erzeuging elektrischer Energie, die einen Zugang (4, 5) fur das erste Gas aufweist, ist erfindungsgemas vorgesehen, dass die Abstromoffnung ausschlieslich durch ein passives Einwegventil (23
Abstract: Bei einem Brennstoffzellensystem mit einer Gaserzeugungseinrichtung (2, 3) und mit einer Brennstoffzelle (1) zur Erzeugung elektrischer Energie, die einen Zugang (4, 5) fur das ihr von der Gaserzeugungseinrichtung zugefuhrte erste Gas sowie wenigstens eine Abstromoffnung (6, 7) fur das erste Gas aufweist, ist erfindungsgemas vorgesehen, dass die Abstromoffnung ausschlieslich durch ein passives Einwegventil (23) verschliesbar und die Gaserzeugungseinrichtung bezuglich der Geschwindigkeit der Gaserzeugung steuerbar ist. Hierdurch wird das gesamte System durch Steuerung der Gaserzeugung kontrollierbar.
Patent•
23 Aug 2007
TL;DR: In this article, a gas accumulator for a micro fuel cell system is described, which can be used in particular to implement micro-fuel cell systems which do not require a pressure controller.
Abstract: The invention relates to a gas accumulator for a micro fuel cell system, to a plurality of methods for producing such a gas accumulator and to a fuel cell system. The gas accumulator (6) according to the invention contains a gas-impermeable wall (4, 5, 8), which bounds a storage volume (3), with at least one first opening (7), via which gas can be supplied to or removed from the storage volume, wherein the wall is mechanically flexible, at least in regions (8), in order to increase and/or reduce the storage volume without generating a substantial pressure difference between the pressure in the storage volume and the external pressure acting on the storage volume. The gas accumulator according to the invention can be used in particular to implement micro fuel cell systems which do not require a pressure controller.