Demonstration of an Automated Assembly Process for Proton Exchange Membrane Fuel Cells Using Robotic Technology

At the recommendation of the ABAT accreditation committee, a new capstone design project class - Engineering Technology Project was introduced at our Engineering Technology Department in the spring semester of 2011. Students work in groups under direct faculty supervision on creative, challenging, open-ending projects proposed by the professor in the area of renewable energy. Practical, hands-on experience is emphasized and analytical and design skills acquired in companion courses are integrated. These projects align with our state’s Third Frontier Fuel Cell Program commitment to accelerate the growth of fuel cell industry in the state, to investigate manufacturing processes and technologies, to adapt or modify existing components and systems that can reduce the cost of fuel cell systems, to address technical and commercialization barriers and to demonstrate market readiness. Projects on which our students worked during the capstone design project class included the design and fabrication of a nine-cell, 50 cm2 active area proton exchange membrane fuel cell (PEMFC) stack, a first ever successful demonstration of an automated assembly process of a PEMFC stack using robotic technology, design and fabrication of instrumentation for measuring physical properties for fuel cell components and the investigation of manufacturing processes for polymer/graphite-based bipolar plates for PEMFCs. As identified by the U.S. Department of Energy, one of the obstacles that remain to be resolved on the road to hydrogen economy is the cost of manufacturing fuel cells. In today’s fuelcell industry the fuel cell stacks are assembled manually in a lengthy process involving a repetitive work cycle in which human errors are common. To our best knowledge the demonstration of an automated assembly line for PEMFCs has not been achieved successfully in the past. The reason is the difficulty to perfectly align the fuel cell components in the stack in order to eliminate overboard reactant leaks as well as the variety of fuel cell components that need to be handled by robot arms. Additional obstacles are the general lack of compliance (flexibility) of the robot joints and the inherent limitations in a robot’s accuracy and repeatability. These latter two factors reduce a robots capability to tolerate and compensate form is aligned parts. In our opinion, another major barrier in the way to successfully demonstrate in the past the feasibility of automated assembly lines for fuel cells was related to an insufficient integration of the fuel cell design process with the design of the automated assembly line. We present an innovative, inexpensive end-effector, the robot work cell and the fuel cell components used to demonstrate successfully for the first time the automated assembly process of a PEMFC stack. The end-effector is capable of handling a variety of fuel cell components including membrane electrode assemblies (MEAs), bipolar plates and gaskets. The end-effector and the fuel cell components are designed with features that allow an accurate component alignment during the assembly process. All fuel cell stack components and the end-effector have been built in house and the automated assembly process has been demonstrated with limited resources and available time by students during the capstone design project class offered in the spring semester of 2011.