Keysight's self-discharge measurement system significantly reduces the time required to measure battery self-discharge current.

BT2191A Cell Self-Discharge Test System Key Features and Specifications

• Measure and record battery self-discharge current, battery voltage, and battery temperature.

• Configure instruments within the system.

• Save or log measurement data.

• Recall previously stored measurement results for display and analysis.

• Export recorded data to Microsoft Excel (xlsx files).

• Matching function measures initial battery voltage and adjusts the applied voltage to expedite self-discharge measurements.

• Allows users to adjust the effective total resistance value (including physical resistors) connected to the battery. This enables users to select the total resistance value to optimize the RC stabilization time for measurements.

BT2191A Cell Self-Discharge Test System Description

Keysight's self-discharge measurement system significantly shortens the time needed to measure battery self-discharge current. Tests show that for small batteries such as cylindrical 18650 or 21700 cells, a stable self-discharge current can be determined within 30 minutes to 2 hours, depending on battery characteristics; for large-capacity pouch cells (e.g., 10-60 Ah), the process typically takes 1-2 hours.

Compared to the traditional method of observing sufficient changes in battery OCV to determine battery quality, which often took weeks or months, this measurement system represents a significant advancement. It greatly shortens your testing cycle, allowing products to reach the market faster.

This self-discharge measurement system uses potentiostatic measurement to quickly determine self-discharge current and provides the functional characteristics necessary for precise DC measurements.

• Minimal Battery Disturbance

  • The applied voltage quickly matches the actual battery voltage (±5 μV). This minimizes new charging or discharging, thereby reducing the new RC stabilization time to a low level.

  • The voltage applied to the battery is highly stable (±10 μVpk), significantly reducing continuous charge redistribution current noise in self-discharge current measurements.

• Measurement accuracy for low-level self-discharge current reaches ±(0.025% + 100nA).

The self-discharge measurement system can also measure battery temperature. This allows you to observe changes in battery voltage and self-discharge current with temperature. Due to the complex temperature coefficients of batteries, monitoring battery temperature helps you control or eliminate voltage variations caused by temperature changes. Controlling voltage variations removes a major source of error in self-discharge current measurements. You can use the T-type thermocouple included with the BT2191A or use your own sensors and wiring. Supported sensors include T, J, K, E, N, R-type thermocouples; 5kΩ thermistors; and Pt100 and Pt1000 RTDs.