Adaptive Battery Cell Diagnosis via Dynamic Excitation
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Solution Overview
Problem
Existing methods for diagnosing battery cell conditions, such as electrochemical impedance spectroscopy, are ineffective during dynamic operations and can damage the battery, failing to provide accurate results and leading to potential hazards due to critical states caused by external conditions and aging.
Innovation Solution
A method involving a current excitation signal with multiple periodic frequencies, adaptive adjustment of signal parameters like amplitude and phase to minimize measurement errors, and continuous impedance measurement to determine battery state variables without damaging the cell, using an excitation unit with a storage capacitor and bi-directional power electronic converter.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional electrochemical impedance spectroscopy is used for battery diagnosis, then measurement precision can be achieved under static conditions, but the method becomes ineffective during dynamic operations and may damage the battery cell
Solution Approach 1:
The patent applies dynamics by making the excitation signal adaptive rather than fixed. The excitation signal's amplitude, frequency, and other parameters are dynamically adjusted based on real-time battery operating conditions to maintain measurement accuracy during both static and dynamic operations. This allows the diagnostic system to adapt to changing battery states without causing damage.
Solution Approach 2:
The patent changes the parameters of the excitation signal (amplitude, frequency, waveform) based on battery state and operating conditions. By varying these parameters adaptively, the system achieves accurate measurements across different operational modes including dynamic charging and discharging, resolving the contradiction between measurement precision and adaptability.
2Measurement precision
If higher excitation signal amplitude is used to improve signal-to-noise ratio, then measurement precision improves, but the risk of damaging the battery cell increases
Solution Approach 1:
The patent dynamically adjusts the excitation signal amplitude based on battery state and operating conditions. During normal operation, lower amplitudes are used to avoid damage. When measurement quality deteriorates, the amplitude is increased only to the extent necessary to maintain acceptable signal-to-noise ratio, thus balancing measurement precision with battery safety.
Solution Approach 2:
The system uses feedback mechanisms to monitor battery response and adjust excitation signal parameters in real-time. Based on the measured impedance and battery state, the control system adapts the excitation amplitude to maintain optimal signal-to-noise ratio while preventing excessive stress on the battery cell.
3Measurement precision
If multiple frequency components are added to the excitation signal to improve diagnostic capability, then measurement precision improves, but device complexity increases
Solution Approach 1:
The patent segments the excitation signal into multiple frequency components that can be independently controlled and adjusted. Each frequency component targets specific battery characteristics, enabling comprehensive diagnostic capability. The segmented approach allows systematic analysis of different battery properties without requiring a completely complex signal generation 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
This approach allows for accurate, continuous monitoring of battery conditions, reducing measurement time and minimizing errors, enabling early detection of critical states and preventing hazards by dynamically adjusting the excitation signal based on operating conditions.
Implementation Method 1
an excitation unit (20) with a storage capacitor (190), wherein the storage capacitor (190) provides an energy to excite a mean value free current excitation signal
Implementation Method 2
recording a response measurement signal and determining the impedance spectrum of the battery cell or the impedance of the battery cell
Data Source
AI summary
An exciter unit, a battery system including the exciter unit, and a method for determining a battery state of at least one battery cell. The method includes: a. applying a current-exciting signal; b. recording an impedance spectrum of the battery cell; c. determining an evaluation variable on the basis of a measured impedance spectrum. At least one of the amplitude, frequency and relative phase difference of at least one component of the current-exciting signal is modified as a function of the first measured response signal such that a measuring error is minimized, a further measured response signal is determined and evaluated, the value evaluated is used as an evaluation variable, and the battery state variables of the battery cell are determined on the basis of a comparison of at least one diagnostic variable with at least one reference value and/or with at least one further diagnostic variable.