3D Printed Flow Field and Fixture for Visualization of Water Distribution in Fuel Cells by X-ray Computed Tomography

This work demonstrates an original approach to three-dimensional, high-resolution, non-destructive visualization of fuel cells during room temperature operation using a commercial micro-X-ray computed tomography (XCT) system. The novel application of 3D printing technology was used to create a customized housing fixture that allows for non-invasive imaging of an operational fuel cell. The use of 3D print materials also allows for rapid prototyping and intricate design of any experimental fixture with minimal cost. Demonstration of imaging capabilities is shown through in situ visualization of the internal MEA components and liquid water after fuel cell operation. Water imaging in fuel cells is particularly challenging using XCT due to small differences in X-ray absorption characteristics between constituent materials. Image processing operations are discussed which allows for the improved segmentation of solid and water to calculate porosity and saturation throughout the gas diffusion layer, as reported herein. Additionally, a membrane thickness increase of approximately 25% due to swelling under 100% relative humidity is shown, which has previously been difficult to determine. Overall, the results shown here illustrate the novel use of 3D printed materials and image processing steps to be further used in understanding of fuel cell devices through non-invasive imaging procedures by use in a commercial micro-XCT system.