Lightweight High-Performance Fuel Cells for Unmanned Aerial Vehicle Propulsion

质子交换膜燃料电池(PEMFC)通过产生水和热，将氢气的化学能直接转化为电能。PEMFC动力装置是汽车和分布式电源应用中最有前途的电源。目前，质子交换膜燃料电池被认为是无人机的替代能源。然而，与其他已用于为无人机提供动力的电源(如内燃机、电池和涡轮螺旋桨)相比，PEMFC动力装置的功率密度要低得多。因此，低功率密度(由重型燃料电池动力装置输出的低功率)是燃料电池供电的无人机(FCUAVs)面临的最关键的挑战。 传统的石墨双极板几乎占燃料电池堆重量的80%。膜水化是低温(~70℃)质子交换膜燃料电池面临的最大挑战之一，因为它直接影响燃料电池的性能和效率。传统的燃料电池动力装置通常需要单独的加湿器和相关的系统，这样才能保证膜的水化效果。 首席调查组在质子交换膜燃料电池和质子交换膜燃料电池-电池动力系统领域做出了重大贡献： (1)建立了一个完整的质子交换膜燃料电池三维通用模型，并将其应用于两相流动和传输机理的研究。 (2)成功搭建、改进了燃料电池试验台，并将其应用于燃料电池性能研究和PEMFC通用模型的验证。 (3)设计和制造了一套电纺装置，用于制备具有更好耐久性和更高性能的纳米纤维和催化剂涂层气体扩散层。 (4)开发了车载和便携式燃料电池-电池混合动力系统的功率管理策略，并进行了实验验证。 (5)燃料电池动力装置控制策略的FCUAV样机设计。 为了制造出高效率、长寿命的质子交换膜燃料电池，迫切需要一种有效的系统化方法来构建具有创新设计、有效和可承受的制造方法的轻质质子交换膜燃料电池堆。 在该方案中，将提出膜、电极和双极板的创新设计和制造，并通过数值和实验方法对其进行表征和研究，并将建立一种有效的系统方法来构建轻质高性能的PEMFC电堆。 所提出的研究结果将显著提高质子交换膜燃料电池的性能，降低成本。随着高素质人员的培训和专业知识的发展，它将对国防和民用应用的FCUAV产生积极和实质性的影响。

A Proton Exchange Membrane Fuel Cell (PEMFC) converts the chemical energy of hydrogen directly into electrical energy with the generation of water and heat. The PEMFC powerplant is the most promising power source for automotive and distributed power applications. Currently PEMFCs are regarded as the alternative power source for Unmanned Aerial Vehicles (UAVs). However, compared with other power sources (e.g., internal combustion engine, battery, and turboprop) that have been used to power UAVs, the power density of the PEMFC powerplant is much lower. Thus, the low power density (low power output by a heavy fuel cell powerplant) is the most critical challenge for fuel cell-powered UAVs (FCUAVs). Conventional graphite bipolar plates contribute almost 80% of a fuel cell stack weight. Membrane hydration is one of the most critical challenges for low-temperature (~70 C) PEMFCs as it directly affects the fuel cell performance and efficiency. In order to properly hydrate the membrane, with the conventional technologies, a separate humidifier and related systems are usually required, which makes the conventional fuel cell powerplants heavy and bulky. The Principal Investigator's group has made significant contributions in the fields of PEMFCs and PEMFC-Battery Power Systems: (1) A comprehensive three-dimensional General Model of PEMFCs was developed, implemented, and applied to deal with two-phase flow and transport mechanisms. (2) A Fuel Cell Test Stand was successfully built, improved, and employed to investigate fuel cell performance and validate the General Model of PEMFCs. (3) An electrospinning setup has been designed and built to fabricate nanofibers and catalyst-coated gas diffusion layers with better durability and higher performance. (4) Power management strategies for fuel cell-battery hybrid systems with vehicles and portable applications have been developed and the experimentally validated. (5) FCUAV prototyping with a focus on the control strategies for the fuel cell powerplant. In order to build a FCUAV with high efficiency and long endurance, there is an urgent need to develop an effective systematic methodology for building a lightweight PEMFC stack with innovative designs and by effective and affordable fabrication methods. In this proposal, innovative designs and fabrications of membrane, electrode, and bipolar plates will be proposed, characterized, and investigated by numerical and experimental methods; and an effective systematic methodology for building a lightweight PEMFC stack with high performance will be established. The results of the proposed research will significantly improve the performance and reduce the cost of PEMFCs. Along with the highly qualified personnel trained and the expertise developed, it will have positive and substantial effects on FCUAVs for defence and civilian applications.