IN Brief:
- Dukosi's evaluation kit provides DCIR and EIS measurements using electronic monitoring hardware fitted at individual battery cells.
- The system supports EIS frequency sweeps from 0.1Hz to 3.5kHz, with one hub accommodating up to 216 Cell Monitor boards.
- Customer benchmarking reported EIS measurement speeds 15 to 20 times faster than selected competing systems, although independent comparative test data has not been published.
Dukosi has introduced an evaluation kit for measuring DC internal resistance and electrochemical impedance at individual lithium-ion battery cells, extending its Smart Cell technology into diagnostic functions used during battery development.
The Edinburgh-based company's platform combines cell-mounted monitoring electronics, a communications hub, and graphical software for configuring measurements and examining results. It is intended for developers evaluating battery management systems used in electric vehicles, industrial equipment, robotics, marine applications, and stationary energy storage.
DC internal resistance, or DCIR, and electrochemical impedance spectroscopy, or EIS, provide complementary information about the electrical behaviour of a battery cell. Both can support assessment of battery condition, but they apply different measurement methods and reveal different characteristics.
Battery management systems commonly monitor voltage, temperature, and current to maintain operation within specified limits. These measurements also contribute to estimates of state of charge, available power, and the condition of cells as they age.
However, the relationship between terminal voltage and internal battery condition changes with operating temperature, state of charge, cell chemistry, and previous use. A voltage reading alone cannot fully describe the resistance and electrochemical processes influencing how a cell responds to a changing electrical load.
DCIR provides a measurement of resistance associated with a controlled current stimulus. The resulting change in voltage can be used to assess the cell's electrical response, including losses that affect the power it can deliver under load.
Internal resistance contributes to voltage drop when current flows. As resistance increases, a cell may reach its minimum permitted voltage sooner during discharge or experience greater electrical losses at a given current. The relationship affects estimates of available power and the limits imposed by the battery management system.
Measured resistance is not an unchanging property of a cell. Temperature, state of charge, the duration of the measurement, and the nature of the applied stimulus all influence the result. Comparisons between cells therefore need to account for the conditions under which their measurements were taken.
Dukosi's DCIR function operates using monitoring hardware located close to the cell terminals. This arrangement reduces the contribution from longer wiring paths and external connections that can influence measurements made further away from the individual cell.
The effect is particularly important when the resistance being measured is small. Resistance introduced by sense wiring, connectors, and other electrical connections can become significant relative to the cell characteristic, making it harder to distinguish changes within the cell itself.
Dukosi states that its DCIR test is self-contained and does not require an external stimulus source. The evaluation software allows developers to configure and examine measurements without constructing a separate laboratory test arrangement around the monitoring electronics.
EIS provides a different view of cell behaviour by applying electrical excitation at selected frequencies and measuring the resulting impedance. Unlike a single DC resistance value, impedance spectroscopy considers how the electrical response changes with frequency.
Different electrochemical processes occur over different timescales. Their contribution to the measured impedance can therefore vary across a frequency sweep, allowing suitable analysis methods to investigate changes associated with the internal behaviour of the cell.
The technique can support investigation of charge-transfer behaviour, resistive contributions, and other electrochemical characteristics. However, assigning an observed feature to a specific physical process requires appropriate interpretation and a model suited to the battery chemistry and measurement conditions.
Dukosi's evaluation kit supports EIS testing over a frequency range from 0.1Hz to 3.5kHz. Developers can conduct a wider frequency sweep or select particular frequencies when investigating a defined characteristic or seeking to reduce the time required for a test.
Lower-frequency measurements generally require longer observation periods than higher-frequency measurements. The duration of a complete EIS sweep therefore depends on the selected frequencies, excitation conditions, and measurement method rather than one fixed time quoted for all possible tests.
Dukosi reports that customers benchmarking its EIS technology against competing solutions observed measurement speeds 15 to 20 times faster, alongside favourable accuracy results. The company has not published a complete independent dataset identifying the reference instruments, settings, or test conditions used in those comparisons.
The evaluation system includes one Dukosi Cell Monitor board, designated DK_DCIR_EIS_CM. Additional boards can be added where developers need to investigate multiple cells within a connected arrangement.
Each cell requires its own monitoring board, while one DK_DCIR_EIS_SH System Hub can accommodate up to 216 boards. The architecture allows cell-level measurements to be organised through a common communications arrangement rather than requiring a separate complete test instrument for every cell.
The kit also includes a reference shunt resistor for verifying the measurement setup before testing live cells, together with supporting cables and accessories. The supplied graphical interface provides a visual representation of the battery configuration and allows operators to switch between DCIR and EIS functions without changing the physical setup.
Communication is based on Dukosi's Smart Cell architecture and C-SynQ technology. By distributing monitoring electronics across individual cells, the system can collect local information and make it available through the shared hub.
Cell-level impedance and resistance measurements can contribute to estimates of state of health and state of available power. Changes in these measurements may indicate that one cell is behaving differently from others in the same battery assembly, providing additional information for diagnosis or further investigation.
The results do not independently determine remaining battery life. Their interpretation depends on the cell's history, chemistry, temperature, state of charge, and the diagnostic model used by the battery management system.
More detailed measurements can also support battery thermal modelling because electrical losses influence heat generation during charge and discharge. Dukosi's existing monitoring technology provides cell-level voltage and temperature information that can be evaluated alongside the new resistance and impedance measurements.
The company is demonstrating the DCIR and EIS evaluation kit at electronica 2026 in Munich from 10 to 13 November. The platform is available for evaluation and proof-of-concept development, allowing customers to investigate the diagnostic approach before integrating the functions into production battery systems.
