Tei Newman-Lehman

Wildcat Discovery Technologies

Temperature control for high-throughput battery testing

Mechanical design and control engineering · 2011–2013

Wildcat’s researchers needed to test coin cells across different temperatures while measuring their electrical behavior at the same time. I designed the multi-position thermal hardware and developed its control system around the laboratory’s existing electrical test equipment.

CNC-machined multi-position heated coin-cell test fixture with spring-loaded electrical contact probes and braided sensor leads.Enlarge imageEnlarge: CNC-machined multi-position heated coin-cell test fixture with spring-loaded electrical contact probes and braided sensor leads.
Heated multi-position coin-cell test fixture pairing independent temperature control at each cavity with four-wire electrical measurement leads. Illustrative image.

Separate temperature settings for the cells

I designed a heated pan with individual cavities for coin cells, giving researchers independently controlled temperature positions while the electrical instrument ran its battery measurements uninterrupted.

The thermal controller maintained the target temperature around each cell while the separate electrical instrument measured how the battery performed, as shown schematically for one representative position below.

Two functions at the same test cell

Temperature control at one battery test position — Temperature feedback returns to a controller that adjusts heating; a separate electrical test measures the cell. One independently controlled position is shown schematically, not as original equipment geometry. Functional illustration of a coin cell above one heated position, with temperature feedback returning to a controller, heat adjustment entering the position, and a separate electrical measurement. Enlarge illustrationEnlarge the functional temperature-control illustration
Each position could hold its own temperature while a separate instrument measured the cell. One representative position, shown schematically · 2011–2013 project

Testing the controller with the hardware in the loop

To tune control performance against the fixture’s real thermal response rather than idealized assumptions, I used hardware-in-the-loop testing on the physical rig. Across several weeks on the bench, I evaluated active heating and cooling approaches, tested temperature-measurement arrangements, and compared PID, fuzzy-logic, and other control methods together—achieving steady-state temperature stability within 0.03°C.

To bring hardware costs down across large multi-channel test racks, I also led the effort to swap out an RTD sensor for a much cheaper thermistor—cutting cost by roughly 30% per assembly while keeping temperature control within spec.

Experience used here

Mechanical design · Thermal control · Hardware-in-the-loop testing · Temperature measurement · Control engineering · Controller tuning

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