Nuvoton Technology, global industry experts in semiconductor technologies for automotive, industrial and embedded systems, has announced the development of a 26-cell battery monitoring IC integrating electrochemical impedance spectroscopy (EIS) for in-system battery health and condition monitoring across electric vehicle and energy storage applications.

The KA85010UA combines conventional cell voltage, current and temperature monitoring with impedance measurement on a single device, allowing battery management systems to evaluate changes occurring within cells without sole reliance on external EIS instrumentation. The architecture is designed to support state of health assessment, internal temperature estimation, lifetime prediction and early identification of developing cell abnormalities by measuring changes in battery impedance across multiple frequency ranges. 

A key design element of the KA85010UA is Nuvoton’s proprietary inductor-based EIS excitation method. Conventional approaches can drive several amperes through a resistor to generate the AC measurement current, dissipating a significant portion of that energy as heat. Nuvoton instead uses two FETs to control current direction while circulating energy stored in an inductor to create the excitation current. In company testing, the method reduced both power loss and PCB temperature rise by approximately 93% compared with its conventional resistor-based approach. The lower thermal load is intended to support impedance measurements across operating, charging and rest conditions without adding the heat burden associated with conventional excitation circuitry.

Nuvoton KA85010UA battery monitoring IC shown in the foreground with an electric vehicle charging in the background, illustrating EIS enabled battery diagnostics for EV applications, featured by EV & Battery Tech Monthly.

Nuvoton’s KA85010UA battery monitoring IC integrates electrochemical impedance spectroscopy to support in-system battery diagnostics across electric vehicle and energy storage applications. (Product Photo Courtesy of Nuvoton; Components Source Network Editorial Backscreen.)

The integrated EIS capability measures battery voltage and current response to an applied AC signal and calculates complex impedance using quadrature detection. Changes across the resulting impedance spectrum can provide information on different electrochemical and electrical conditions within the battery. Nuvoton identifies higher frequency measurements with changes in terminals, wiring and electrolyte behavior, while mid and lower frequency responses provide information associated with electrode behavior and internal electrochemical reactions.

The company has also developed EIS analysis algorithms to support interpretation of the acquired impedance data. Nuvoton says this work builds on joint verification with automotive manufacturers and research institutions and supports development from measurement setup and battery data acquisition through state estimation, abnormality detection and application integration. The company has previously conducted joint battery diagnostics research with Japan’s National Institute of Advanced Industrial Science and Technology (AIST), including work involving battery degradation and internal temperature estimation.

The KA85010UA supports up to 26 cells and provides cell voltage, current and temperature measurements in addition to EIS. Nuvoton specifies voltage measurement accuracy of ±2.0 mV at end of life and identifies the device as ISO 26262 compliant to ASIL-D and AEC-Q100 compliant. The monitoring IC is intended for automotive batteries, large scale energy storage systems and reused battery diagnostic applications.

Integrating impedance measurement into the battery monitoring architecture expands the information available to battery management systems beyond conventional voltage, current and temperature data. Under company defined evaluation conditions, Nuvoton compared measurements from the device with dedicated EIS equipment and 1 kHz AC internal resistance measurements specified in IEC 62620 and reported a high level of agreement. Related joint research results with AIST have also been published through IEEE.

Samples of the KA85010UA are scheduled to become available in January 2027.

About Nuvoton Technology Corporation Japan

Nuvoton Technology Corporation Japan is a semiconductor manufacturer developing technologies and devices for automotive, industrial, consumer and embedded applications. The company became part of the Nuvoton Technology group in 2020 and builds on more than six decades of semiconductor development experience in Japan. Its technology portfolio spans battery management, automotive electronics, microcontrollers, sensing, power management, audio, imaging and other semiconductor solutions. Within battery management, Nuvoton develops monitoring ICs and supporting technologies for electric vehicles, energy storage systems and other high-capacity battery applications, including cell monitoring, electrochemical impedance measurement and battery condition analysis. For more information, please click here. 

Source: Nuvoton Technology Corporation

(Editor’s Note: All trademarks mentioned in this article, including company names, product names, and logos, are the property of their respective owners. Use of these trademarks is for informational purposes only and does not imply any endorsement.)

Molly Bakewell Chamberlin
Latest posts by Molly Bakewell Chamberlin (see all)
Tagged