Sidney Starr
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Cells built for the laser

Designing and 3D-printing my own battery test cells so a laser can look inside while they run, and iterating on the design in days instead of weeks.

A spectroelectrochemical cell, in cross-section (generic schematic)A microscope objective focuses a laser down through a thin window into a liquid electrolyte, onto the working electrode. A counter electrode sits nearby. The 3D-printed body holds everything at a fixed spacing and seals the liquid in.microscope objectiveelectrolyte (water-based)windowworking electrode(zinc)counter electrode3D-printed body: spacing, volume, seal
Fig. 1 · SchematicThe general idea of a spectroelectrochemical cell. This is a generic drawing, not my actual design.

The short version

To watch a battery with a laser, the battery has to have a window, sit under a microscope, hold the right amount of liquid, keep its electrodes at the right spacing, and not leak. Off-the-shelf cells rarely do all of that at once, so I design my own and 3D-print them in PETG on a Bambu Lab X2D.

Printing in-house means a design change can go from idea to a cell on the bench quickly, which changes how you experiment: you can try the version you’re unsure about instead of over-planning one expensive part.

What a cell has to get right

  • An optical path: the laser has to reach the electrode surface and the scattered light has to get back out.
  • Geometry: electrode spacing and electrolyte volume affect the electrochemistry you’re measuring.
  • Sealing and chemistry: the plastic has to hold the electrolyte without leaking or reacting with it.
  • Repeatability: if every cell is a little different, comparisons between experiments get harder.

TODO(Sidney): which of these were the hardest to solve, how many design iterations you've gone through, and what changed between versions.

Technical depth: design and fabrication

Cells are modeled in CAD and printed in PETG on a Bambu Lab X2D. TODO(Sidney): CAD tool, why PETG (chemical compatibility, printability), how you seal windows and electrodes, any post-processing, and tolerances that matter.

Photos

TODO(Sidney): photos of cell prototypes and an exploded CAD render (see the shot list in CONTENT_PLAN.md).

  • 3D printing
  • instrumentation
  • CAD
  • electrochemistry

Results and data from this work will be shared once they’re published or cleared with my research group.