Overview This CAD set contains the 3D printable files for a custom-designed compression holder used for operando active acoustic monitoring of coin cell batteries. The assembly is designed to securely align two ultrasonic transducers (emitter and receiver) on either side of a coin cell, maintaining consistent coupling pressure via a mechanical spring during electrochemical cycling. This setup allows for the continuous monitoring of acoustic metrics (such as Time-of-Flight and signal attenuation) to study structural and mechanical evolution within the battery. Bill of Materials (Hardware & Components) To replicate this experimental setup, the following non-printed components are required: Acoustic Sensors: 2x Ultrasonic Contact Transducers. Diameter: 19 mm (~0.75 inch). Connector: Side-mounted Microdot (10-32). Hardware: 1x CR2032-size coin cell 1x Mechanical compression spring (to maintain constant acoustic coupling pressure). 1x M10 fastening bolt (for spring tensioning). 1x M10 nut (for housing assembly, inserted as inset during the 3D print of retainer_cap). 2x Flat disks with electrical connectors (for electrochemical cycling of the cell) Coaxial cables (Microdot to BNC/SMA) connecting to the ultrasonic pulser/receiver. 3D Printing Specifications The provided 3D models (main housing, transducer carriage, and end-caps) are optimized for Fused Deposition Modeling (FDM). Material: PETG (Polyethylene Terephthalate Glycol) Infill Density: 40% Layer Height: 0.20 mm Assembly Notes The primary housing accommodates the stationary transducer at the base. The coin cell is sandwiched between this base transducer and the top transducer, which sits within a sliding carriage. The spring is sandwiched between the bottom_cap and top_cap parts, and screw assembly applies constant downward pressure onto the carriage, ensuring stable acoustic coupling throughout the charge/discharge cycle regardless of slight volumetric changes in the cell.The nut must be inserted as inset during the 3D print of the retainer_cap part.