Nuvoton Technology Corporation Japan has introduced the KA85010UA, a sixth-generation battery monitoring IC that integrates electrochemical impedance spectroscopy (EIS) for electric vehicle (EV) battery diagnostics.
The IC monitors up to 26 battery cells and uses EIS to assess internal battery conditions that are difficult to identify through conventional voltage and temperature measurements alone. The technology is designed to help estimate battery state of health (SOH) and internal temperature while identifying early signs of cell abnormalities.
EIS works by applying an ac current to a battery and calculating impedance from the resulting voltage and current responses. Different frequency ranges provide information about the battery’s internal components and electrochemical processes. Integrating this capability into the monitoring IC allows impedance measurements to be performed within the battery system without separate laboratory equipment.
The KA85010UA uses a proprietary inductor-based excitation method to reduce heat generation during EIS measurements. Rather than dissipating energy through a resistor, the circuit uses two switching transistors to control current through an inductor and circulate stored energy as the measurement current.
In Nuvoton’s testing, this approach reduced both power loss and printed circuit board (PCB) temperature rise by approximately 93% compared with conventional resistor-based EIS measurement methods. The lower heat generation allows measurements across different battery operating conditions, including charging and vehicle operation.
The IC provides cell voltage measurement accuracy of ±2.0 mV at end of life and incorporates voltage, current, and temperature monitoring. It is listed as compliant with ISO 26262 ASIL-D and AEC-Q100 automotive requirements.
Nuvoton also provides EIS analysis algorithms developed using experience from joint verification with automakers and research institutions. These tools are intended to help battery management system developers interpret impedance measurements and integrate diagnostic functions into EV battery applications.
Under specified evaluation conditions, Nuvoton compared EIS measurements from the KA85010UA with dedicated laboratory equipment and 1-kHz ac internal-resistance measurements. The company reports strong agreement between the measurement methods, with verification findings documented in research published in IEEE Transactions on Instrumentation and Measurement.
The company will showcase the technology at The Battery Show North America, October 12–15 at Huntington Place in Detroit, Michigan (Booth 5227).
Filed Under: Batteries, Technology News, Test And Measurement