High power density fuel cell systems for portable electric generators

I. Kruusenberg, Y. Okuyama, K. Chadha
PowerUP Fuel Cells,

Keywords: fuel cells, portable generators, PEMFC, sustainable, hydrogen


It is of utmost importance to develop lightweight fuel cell stacks and find the ways to integrate these to light weight and low temperature fuel cell systems. In order to meet the future energy demands non-polluting, compact, transportation and portable applications are required. Current energy systems have lower power density (kW/kg) resulting in optimized power only at higher overall weight. Systems with higher power density demand higher initial setup costs. Low temperature PEMFC, on other hand, offers various advantages but fails to provide the required output without exceeding the weight of the fuel cell stack and thereby fuel cell systems. A liquid cooled fuel cell system consists of a fuel cell stack, hydrogen system (compressed gas in cylinder, pressure regulator, supply valve, pressure relief valve, purge valve, gas/water separator, etc.), air system (air filter, air compressor intercooler, humidifier, pressure control valve, etc.), cooling system (water pump, bypass valve, radiator, deionizer, etc.), temperature sensors, pressure sensors and CVM (Cell Voltage Monitor). A fuel cell stack is the main component consisting of one of the devices with maximum weight and cost contribution. In such a case, developing a system with a stack having higher power density reduces overall weight and increases power density (kW/kg). PowerUP Energy Technologies has developed a light weight fuel cell stack to achieve higher power density. Experiments considering flow field designs of bipolar plates, MEA (Membrane Electrode Assembly) design, recirculation strategy, different anode configuration have been a subject of study. Dead-end anode, closed cathode configuration of fuel cell stack further improves fuel utilization. Recirculation line of hydrogen if further added can improve overall fuel utilization. Counter flow arrangement for reactant distribution in bipolar plates further removes the necessity of humidifying the gases. This results in removal of humidifiers and thereby reducing the weight of the fuel cell system in total. Also, high performance MEA at high current density results in reducing total active area, leading to weight and cost reduction as a result. Portable fuel cell systems have flexibility for ease in transportation and stationery solutions. Furthermore, lighter fuel cell stacks add advantage for higher output power at lower overall weights. This stack is further optimized with improved flow field designs and design of manifolds. These fuel cell stacks are used in PowerUP’s portable fuel cell electric generators that are more efficient and sustainable than the currently used fossil fuel based solutions.