How is EIS accuracy preserved with long cell cables?

Key points

• The measurement chain: chassis, channel board, cell cable and accessories (extension cables, battery holders). Each link can affect measurement quality positively or negatively.
• The accuracy contour plot shows which error band applies at which |Z| and frequency. The top area (high impedance) is critical for coatings and insulating materials, the bottom area (low impedance) for batteries, supercapacitors, fuel cells, electrolysers and flow batteries.
• Bio-Logic DC and EIS specifications are established with standard cables that reflect real laboratory use: 1.50 m for the Essential range and 1.75 m for the Premium range.
• In the Essential range cables can be swapped without shutting the instrument down. The extra length of a longer cable affects high-impedance accuracy but not low impedance; the EC-Lab post-processing algorithm compensates for it with two initial measurements.
• In the Premium range the cable is paired with the channel board and factory calibration is valid up to the end of the cable regardless of its length; the electrometer allows precise calibration of the low current ranges.
• Battery holders, high-temperature extension cables and material holders such as the CESH-e are designed for 4-point connection and low parasitics.

Figures

Images: Bio-Logic Science Instruments; taken from the source article.

Related application notes

• How is the instrument's EIS accuracy contour plot read? Battery AN54
• What precautions should be taken for a good EIS measurement? Electrochemistry AN5
• Which artefacts do reference-electrode impedance and instrument parasitics create in EIS? Battery AN44