Battery State of Charge Detection Using Pulse Impedance Analysis
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Solution Overview
Problem
Conventional methods for detecting the state of charge (SOC) of batteries are either time-consuming, inaccurate, or require expensive equipment, making them unsuitable for general battery management systems, especially for batteries with small open-circuit voltage changes or those affected by polarization.
Innovation Solution
A method and apparatus that input a pulse to the battery to measure a response curve, calculate a simulated curve, and compare it to a predetermined threshold, using a pulse generator, analog/digital converter, and controller to determine SOC based on the resistance of a charge transfer resistor, allowing for fast and precise measurements without prolonged battery stationary time or complex calculations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If open circuit voltage measuring method is used, then the measurement process is simpler, but the measurement takes too much time due to battery stabilization requirement
Solution Approach 1:
The patent applies periodic pulse signals to the battery instead of requiring continuous stabilization. By using periodic excitation signals and analyzing the impedance response, the system can determine SOC dynamically during charge/discharge operations without waiting for the battery to reach a stationary state, thus resolving the time-consuming issue while maintaining measurement simplicity
Solution Approach 2:
The patent replaces the traditional voltage-based measurement system with an impedance-based measurement system. By measuring the battery's impedance response to pulse signals and analyzing the charge transfer resistance, the system eliminates the need for open-circuit voltage stabilization while achieving accurate SOC determination through electrical parameter analysis
2Measurement precision
If electrochemical impedance spectroscopy measuring method is used, then parameters presenting different SOCs can be obtained, but the measurement consumes excessively long time and requires expensive equipment
Solution Approach 1:
The patent extracts only the essential impedance information needed for SOC determination by using simple pulse signals instead of comprehensive multi-frequency impedance spectroscopy. By focusing on the charge transfer resistance parameter obtained from pulse response analysis, the system achieves sufficient measurement precision while dramatically reducing measurement time and equipment requirements
Solution Approach 2:
The patent replaces expensive electrochemical impedance spectroscopy equipment with simple, low-cost pulse signal generation and measurement circuits. By using basic microcontroller units with pulse output capabilities and simple voltage measurement, the system achieves accurate SOC measurement without requiring sophisticated impedance spectroscopy instruments, making the solution economically viable for general battery management systems
3Measurement precision
If electrochemical impedance spectroscopy measuring method is used, then parameters presenting different SOCs can be obtained, but the computations are complicated when polarization is considered
Solution Approach 1:
The patent extracts only the essential charge transfer resistance parameter from the impedance response by using simplified pulse signal analysis. By focusing on the steady-state current response to pulse voltage signals and calculating resistance directly from Ohm's law, the system eliminates complex polarization modeling and computation while maintaining sufficient measurement accuracy for practical SOC determination
Solution Approach 2:
The patent changes the measurement approach from analyzing complex impedance spectra across multiple frequencies to measuring simple voltage-current relationships during pulse excitation. By transforming the measurement parameter from complex impedance to simple resistance calculation, the system reduces computational complexity while maintaining the ability to track SOC changes through resistance variations
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
Enables rapid, accurate SOC measurements by eliminating the need for prolonged battery stabilization and reducing polarization interference, simplifying the measurement process, and reducing costs by using a single-frequency pulse, thus facilitating convenient implementation in battery management systems.
Implementation Method 1
inputting a pulse to the battery to measure a response curve of the battery associated with the pulse
Implementation Method 2
The corresponding relationship indicates a correspondence between the SOC of the battery and a resistance of a charge transfer resistor of the battery
Data Source
AI summary
A method for detecting a state of charge (SOC) of a battery is disclosed. The method includes inputting a pulse to the battery for receiving a response curve of the battery associated with the pulse inputted to the battery, determining a set of parameters for preparing a simulated curve, comparing a difference between the response curve and the simulated curve, determining whether the difference between the simulated curve and the response curve is less than a predetermined threshold before further utilizing the parameters to determine the SOC from a corresponding relationship.