Battery EIS Analog Circuitry for Fast Impedance Phase Detection

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Solution Overview

Problem

Conventional electrochemical impedance spectroscopy (EIS) systems for battery health monitoring require significant computational resources and time due to digital processing of sampled data, especially with conventional stimulus signals ranging from mHz to kHz, leading to high memory and computational demands.

Innovation Solution

Implementing analog circuitry for synchronous acquisition of voltage and current signals associated with a battery's response, reducing the need for digital computation and enabling faster EIS analysis with lower memory requirements and reduced physical footprint.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If digital processing of sampled data is used for EIS analysis, then measurement precision is improved, but device complexity and computational resources increase

Engineering Contradiction:

ImproveEIS measurement precisionVSAvoidcomputational resources

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent replaces digital signal processing systems with an analog measurement system that directly computes impedance parameters. The analog circuitry processes voltage and current signals through synchronous detection and mathematical operations performed in the analog domain, eliminating the need for digital sampling, ADC conversion, and computational algorithms like FFT, thereby reducing device complexity while maintaining measurement precision

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent introduces an analog measurement system as an intermediary between the stimulus signal and the impedance measurement. This intermediate analog processing stage performs synchronous detection and real-time mathematical operations (multiplication, division, square root) to directly extract impedance magnitude and phase, serving as a mediator that converts raw voltage/current signals into impedance parameters without requiring digital computation

Inventive Principle:

Principle #24Intermediary (Mediator)

2Adaptability or versatility

If conventional stimulus signals (mHz to kHz) are used, then adaptability is improved, but loss of time increases

Engineering Contradiction:

Improvefrequency range coverageVSAvoidmeasurement time

Core Design Contradiction:

Adaptability or versatilityVSLoss of time

Solution Approach 1:

The patent employs periodic stimulus signals (sinusoidal or square waves) at selected frequencies to excite the battery system. By using periodic excitation with known frequency characteristics, the system can efficiently extract impedance parameters through synchronous detection, maintaining adaptability across frequency ranges while reducing measurement time compared to conventional sweeping methods

Inventive Principle:

Principle #19Periodic action

Solution Approach 2:

The patent performs preliminary selection of stimulus frequencies based on expected battery characteristics and measurement objectives. Rather than sweeping through all frequencies from mHz to kHz, the system pre-selects optimal frequencies for the specific measurement context, enabling faster acquisition of relevant impedance data while maintaining adaptability to different battery types and states

Inventive Principle:

Principle #10Preliminary action

3Measurement precision

If digital processing with high memory requirements is used, then measurement precision is improved, but volume of device increases

Engineering Contradiction:

ImproveEIS data accuracyVSAvoidphysical footprint

Core Design Contradiction:

Measurement precisionVSVolume of stationary object

Solution Approach 1:

The patent replaces digital processing systems requiring large memory and computational resources with an analog measurement system that performs real-time signal processing through physical circuit operations. The analog circuitry directly computes impedance parameters from voltage and current signals using operational amplifiers, multipliers, and function generators, eliminating the need for large digital memory buffers and reducing the physical footprint of the measurement device

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The proposed system achieves faster EIS analysis with lower computational resources and reduced physical space, while maintaining accurate battery health monitoring capabilities.

Implementation Method 1

Electrochemical impedance spectroscopy (EIS) may be used to generate information for determining a state of health of batteries

Methodology Applied

Scientific EffectElectrochemical impedance spectroscopy:

Data Source

PatentUS20250341588A1Electrochemical impedance spectroscopy phase and amplitude detection of a stimulated system

Publication Date: 2025.11.06 STMICROELECTRONICS INT NV

AI summary

Systems, apparatuses, and methods for electrochemical impedance spectroscopy (EIS) for use with batteries, including for EIS phase and amplitude detection of a stimulated system are provided. A battery management system comprising EIS circuitry is electrically coupled to a battery. The EIS circuitry provides a stimulus signal to the battery to generate a response signal from the battery. A current signal and voltage signal are generated by the EIS circuitry based on the response signal from the battery. The EIS circuitry generates at least one output signal based on the current signal and the voltage signal, and an impedance is generated based on the at least one output signal.