A micro heater platform with fluid channels for testing micro-solid oxide fuel cell components

Abstract

Micro-scale solid oxide fuel cells (µ-SOFCs) constitute a promising power generation technology for portable devices such as aerospace exploration, medical devices and consumer electronics. Fuel cell systems include several functional units providing gas reforming, electrochemical power generation, and post-combustion of unused fuel. All such units require operation at controlled temperature with appropriate gases. Although various µ-SOFC components have been demonstrated, the evaluation of the thermal balance is cumbersome, as there is no micro platform providing thermal insulation, controlled heating, temperature control, and gas exchange. Our testing platform is designed for this purpose. It consists of two sealed glass substrates with integrated platinum thermistors for heating and temperature control, and channels to supply and evacuate gases. Its fabrication is compatible with silicon chip bonding. The heating elements are thick-film platinum thermistors allowing to heat up to 700°C. Efficient thermal decoupling along the carrier allows convenient lowtemperature electrical and fluidic connections. A fluidic MEMS module -a prototype gas reformer -was bonded onto the carrier to demonstrate tight gas connections at elevated temperature. Laboratoire de Production Microtechnique (LPM) AbstractMicro-scale solid oxide fuel cells (µ-SOFCs) constitute a promising power generation technology for portable devices such as aerospace exploration, medical devices and consumer electronics. Fuel cell systems include several functional units providing gas reforming, electrochemical power generation, and post-combustion of unused fuel. All such units require operation at controlled temperature with appropriate gases. Although various µ-SOFC components have been demonstrated, the evaluation of the thermal balance is cumbersome, as there is no micro platform providing thermal insulation, controlled heating, temperature control, and gas exchange. Our testing platform is designed for this purpose. It consists of two sealed glass substrates with integrated platinum thermistors for heating and temperature control, and channels to supply and evacuate gases. Its fabrication is compatible with silicon chip bonding. The heating elements are thick-film platinum thermistors allowing to heat up to 700°C. Efficient thermal decoupling along the carrier allows convenient low-temperature electrical and fluidic connections. A fluidic MEMS module -a prototype gas reformer -was bonded onto the carrier to demonstrate tight gas connections at elevated temperature.

A low-temperature co-fired ceramic micro-reactor system for high-efficiency on-site hydrogen production

“…A similar design can be found in silicon-based micro-reactors [12,28], with the difference that the high thermal conductivity of silicon materials requires a more sophisticated thermal decoupling structure. A "larger" glassbased micro-reactor with a similar cantilever shape for thermal decoupling was reported in our previous and forthcoming work [15,29]. This system achieved a good thermal decoupling by using a combination of low thermal conductivity of glass (1.16 W m À1 K…”

A thermally self-sustained micro-power plant with integrated micro-solid oxide fuel cells, micro-reformer and functional micro-fluidic carrier

“…Hermetic sealing was achieved after firing in air at 700 °C for 20 min with a weight of 80 g. The micro-SOFC chip was subsequently glued with cement paste (TAKETSUNA Manufactory CO., LTD) to the underlying micro-reformer ( Figure 1). The dimensions of the glass carrier and of the micro-reformer are slightly different to those reported in our earlier works [5,11,[28][29][30]36]. They were adjusted to meet the dimensions of the chip containing the micro-SOFC membranes in order to avoid closing off membranes by the cement paste used for bonding.…”

“…Both, gas inlet and outlet at the "cold"-end of the functional carrier, were always kept below 50 °C [28]. The temperature at the "hot"-end was measured by a thermocouple touching the top of the Si-chip containing the micro-SOFC membranes.…”

Development of a Novel 2-Dimensional Micro-Heater Array Device with Regional Selective Heating

“…For example, in order to control the temperature with a high accuracy, a heater element and a temperature sensor can be integrated on the same chip. In this case, a heater element and a thermistor (a type of temperature sensor) were fabricated from nickel (Ni) and platinum (Pt), and therefore had a resistance that varied more strongly with temperature than sensors made from other materials (Jiang et al, 2012;Resnik et al, 2011;Tao & Tsai, 2002;Yoon et al, 2002;Yan et al, 2008). There are many other cases where combinations of different material properties are used for a variety of purposes.…”