Robotic Manufacturing System for Unattended Machining and Inspection of Graphite Bipolar Flow Field Plates for Proton Exchange Membrane Fuel Cells

A single robot-based manufacturing system for unattended machining and inspection of graphite bipolar flow field plates for proton exchange membrane fuel cells is designed and integrated for demonstration and validation. Unlike most robotic manufacturing systems where an industrial robot is used for tending an automated tool such as a computer numerical control machine, in the present system the industrial robot performs all manufacturing operations, including machining the flow fields on both sides of the plates, changing the tools, handling the plates, vacuuming the plates and the workholding device of graphite dust, flipping the plates, air blowing them and performing machine vision inspection for quality control. The toolpath for robotic machining the flow fields and the manifolds are generated offline using Roboguide simulation software. The manufacturing system uses an integrated machine vision inspection process as a diagnostic tool for in-line checking the presence of machined features and in-line verification of feature dimensions. Besides the considerably lower capital cost compared to other automated manufacturing systems resulted from the elimination of the automated machine tool, the proposed robotic cell has the advantage of better managing the abrasive graphite dust resulted in the manufacturing process. The limitations of the proposed robotic cell are assessed and recommendations for further development are considered. The manufacturing system is demonstrated as part of a larger endeavour of bringing to readiness advanced manufacturing technologies for renewable energy devices and responds the high priority needs identified by the U.S. Department of Energy for fuel cells manufacturing research and development

Robotic Technologies for Proton Exchange Membrane Fuel Cell Assembly

Proton exchange membrane fuel cell (PEMFC) stacks and their components are currently being manufactured using laboratory fabrication methods. While in recent years these methods have been scaled up in size, they do not incorporate high-volume manufacturing methods. In this context, manufacturing R&D is necessary to prepare advanced manufacturing and assembly technologies that are required for low-cost, high-volume fuel cell power plant production. U.S. Department of Energy (DOE) has identified high-priority manufacturing R&D needs for PEMFCs. Along with efforts to develop technologies for high-speed manufacturing of fuel cell components, DOE identified the need for demonstrating automated assembly processes for fuel cell stacks. The scope of this chapter is to review current manufacturing R&D efforts in the area of automated processes for assembling PEMFC stacks, to present the current state of development, successful demonstrations, related technological challenges and the technical solutions used to overcome them. An emphasis of this review is on the design of tools used for robotic grasping, handling and inserting fuel cell components in the stack and on the use of design for manufacture and assembly (DFMA) strategies that enable the automated assembly process

Design of a Methanol Reformer for on-board Production of Hydrogen as Fuel for a 3kW High-temperature Proton Exchange Membrane Fuel Cell Power System

The method of Computational Fluid Dynamics is used to predict the process parameters and select the optimum operating regime of a methanol reformer for on-board production of hydrogen as fuel for a 3 kW High-Temperature Proton Exchange Membrane Fuel Cell power system. The analysis uses a three reactions kinetics model for methanol steam reforming, water gas shift and methanol decomposition reactions on Cu/ZnO/Al2O3 catalyst. Numerical simulations are performed at single channel level for a range of reformer operating temperatures and values of the molar flow rate of methanol per weight of catalyst at the reformer inlet. Two operating regimes of the fuel processor are selected which offer high methanol conversion rate and high hydrogen production while simultaneously result in a small reformer size and a reformate gas composition that can be tolerated by phosphoric acid-doped high temperature membrane electrode assemblies for proton exchange membrane fuel cells. Based on the results of the numerical simulations, the reactor is sized, and its design is optimized

Bridging the Gap between Automated Manufacturing of Fuel Cell Components and Robotic Assembly of Fuel Cell Stacks

Recently demonstrated robotic assembling technologies for fuel cell stacks used fuel cell components manually pre-arranged in stacks (presenters). Identifying the original orientation of fuel cell components and loading them in presenters for a subsequent automated assembly process is a difficult, repetitive work cycle which if done manually, deceives the advantages offered by either the automated fabrication technologies for fuel cell components or by the robotic assembly processes. We present for the first time a robotic technology which enables the integration of automated fabrication processes for fuel cell components with a robotic assembly process of fuel cell stacks into a fully automated fuel cell manufacturing line. This task uses a Yaskawa Motoman SDA5F dual arm robot with integrated machine vision system. The process is used to identify and grasp randomly placed, slightly asymmetric fuel cell components, to reorient them all in the same position and stack them in presenters in preparation for a subsequent robotic assembly process. The process was demonstrated as part of a larger endeavor of bringing to readiness advanced manufacturing technologies for alternative energy systems, and responds the high priority needs identified by the U.S. Department of Energy for fuel cells manufacturing research and development

Design and Demonstration of Automated Technologies for the Fabrication and Testing of PEM Fuel Cell Systems

This paper describes the research efforts at Georgia Southern University to develop robotic technologies for the fabrication of fuel cell components and stacks, as well as the design and fabrication of a High Temperature Proton Exchange Membrane Fuel Cell (HT-PEMFC) power system to be used as motive power and auxiliary power unit (APU) for a long range, unmanned, fully autonomous forest rover. The paper describes a manufacturing workcell consisting of a Yaskawa Motoman SDA5F dual arm robot with machine vision used for sorting, reorientation and stacking fuel cell components in presenters in preparation for their subsequent robotic assembly in fuel cell stacks. It also describes a manufacturing workcell consisting of a Fanuc LR Mate 200iD robot, an in-house made computer numerically controlled (CNC) router and programmable logic controller (PLC) used for automated fabrication of graphite bipolar plates for fuel cells. It presents the design and integration of a fully automated test stand used for testing fuel cells up to 4 kWe power and the design and fabrication of a 250 W, 166 cm2 active area fuel cell stack prototype. The operation characteristics of this short stack prototype are studied before a larger 3 kW fuel cell system will be built

Two-dimensional mathematical model and numerical simulation of the transport processes and cell performance of proton exchange membrane fuel cells

A two dimensional, mathematical model for the entire sandwich of a proton exchange membrane (PEM) fuel cell including the gas channels' is developed. To take into consideration the real concentration distributions along the interface between the gas diffuser and catalyst layer, transport equations are solved simultaneously for the domain consisting of the coupled gas channel, gas diffuser, catalyst layer and membrane. The self-consistent schematical model for porous media is used for the equations describing transport phenomena in the membrane, catalyst layers and gas diffusers, while standard Navier-Stokes, energy transport, continuity and species concentration equations are solved in the gas channels. A special handling of the transport equations enabled us to use the same numerical method to solve them, and therefore to treat the gas channel-gas diffuser-catalyst layer domains as an entirety, avoiding arbitrary boundary conditions at their interfaces. The oxygen and water vapor mole fraction distribution in the coupled cathode gas channel-gas diffuser is studied for different values of the operating current density. Influences of the inlet conditions at the gas channel entries and of the gas diffuser porosity on the cell performance are also analyzed.</p

Supplemental Files: Laser Scanner-Based Robotic Coordinate Measuring Machine

This data represents the LabView and C++ software necessary to operate the coordinate measuring machine (CMM) described in the related publication, as well as raw data results representing the digitized model of a section of a turbine blade obtained using the CMM. This data is shared as supplemental material for the related publication: V. Gurau, A. Gerhardstein, K. Carruthers and H. Frazer: “Laser Scanner-Based Robotic Coordinate Measuring Machine”, in International Journal of Mechanical Engineering and Robotics Research (2023)

Design and Demonstration of Automated Technologies for the Fabrication and Testing of PEM Fuel Cell Systems

Presentation given at the International Conference on Mechanical, Materials and Manufacturing