High-current Pulses for Battery Research

IntroductionGamry Reference 3000 potentiostat w/ 30k Booster for high current battery pulsing

For those interested in determining the characteristics of batteries, especially by discharging them to see their changes in impedance, Gamry Instruments offers the Reference™ 3000 potentiostat plus our 30k Booster. This combination of instruments is useful for running stress tests on batteries, by applying rapid, high-current pulses singly or repeatedly.

As a cell, we used our 30k Test and Cal cell. The 30k Test and Cal cell printed circuit board was carefully designed for:

  • True four-terminal sensing on both the Test and Calibration sides of the Cell
  • Minimal inductance in the current-carrying connections
  • Minimal mutual inductance between the current-carrying and sensing circuits.

Gamry Instruments uses the Calibration side of the cell to galvanostatically measure impedance spectra

at frequencies up to 300 kHz with less than 2° of phase error.

This Application Note shows results of our own research into the characteristics of our equipment.

Experimental

The tests were run on a Reference 3000 and Reference 30k Booster. A Gamry Reference 30k Test and Cal cell was connected to the booster in all tests. The cell connections used the standard cables supplied with the system: a 1 m current-carrying cable and a 1.5 m sense cable.

Most of the testing was done on the Calibration side of the Test and Cal cell. This side is a 200 mΩ resistor with a 2.5 A fast-blow fuse in the counter electrode lead. The fuse protects the 1 W resistor from damage caused by excessive current flow. The resistance of a sample fuse was measured to be 34 mΩ. Fast current pulses larger than the 2.5 A fuse rating will not blow the fuse if the pulses are short enough.

The Test side of the Test and Cal Cell is a 3 mΩ four-terminal resistor. It does not require a fuse because it can safely pass 30 A currents.

Many tests were performed at different CA (control amplifier) Speed settings. The faster the CA Speed is, the better time-resolution is achieved, but at the cost of stability in the amplifier.

Most data were recorded using our signature Framework™ software. Some of the tests required use of a Tektronix 2024C digital oscilloscope instead.

Results

Please visit Gamry.com’s application note for the ‘results’ and to download a PDF version of the complete application note,

High-current Pulses for Battery Research

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