Impedance Measurement Phase Correction for Laminated Battery Accuracy
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Solution Overview
Problem
The existing impedance measuring devices for laminated type batteries, such as fuel cell batteries, face accuracy issues due to capacitance components that cause phase differences between detection signals, leading to leakage of alternating current to the load and subsequent reduction in measurement accuracy.
Innovation Solution
The impedance measuring device adjusts the amplitude of alternating currents output to the positive and negative electrodes to ensure equal potential differences, and includes a phase difference detection unit to diagnose measurement state defects, allowing for phase correction and error revision to maintain measurement accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If alternating current is output to both positive and negative electrodes to measure impedance, then impedance measurement can be performed, but phase difference caused by capacitance components causes current leakage to load and reduces measurement accuracy
Solution Approach 1:
The patent applies preliminary action by detecting the phase difference between detection signals from the positive and negative electrodes before performing impedance measurement. The phase difference detection unit identifies any phase deviation caused by capacitance components in advance, allowing the system to determine whether the measurement state is reliable before actually measuring impedance. This prevents inaccurate measurements from being performed in the first place.
Solution Approach 2:
The patent implements feedback by using the phase difference detection results to control whether impedance measurement should be executed. The determination unit receives feedback from the phase difference detection unit about the measurement state reliability, and based on this feedback, either permits or prohibits the impedance measurement. This closed-loop control ensures that measurements are only performed when the phase difference is within acceptable limits.
2Adaptability or versatility
If capacitance components are present in the battery, then the battery can function normally, but phase difference is generated between detection signals causing measurement accuracy reduction
Solution Approach 1:
The patent converts the harmful effect of capacitance components (which cause phase difference and measurement errors) into a useful diagnostic indicator. By detecting the phase difference caused by capacitance, the system can determine the reliability of the measurement state. The previously harmful phase difference is now used as a criterion to gate whether measurement should proceed, turning a source of error into a quality control mechanism.
3Measurement precision
If phase difference detection and measurement state determination units are added, then measurement accuracy can be maintained, but device complexity increases
Solution Approach 1:
The patent achieves multi-functionality by having the detection signals serve dual purposes: they are used both for the primary impedance measurement and for the secondary phase difference detection. The same detection circuitry that measures voltage for impedance calculation also provides the phase difference information needed for reliability determination. This eliminates the need for completely separate dedicated phase detection hardware.
Solution Approach 2:
The system performs self-diagnosis by using its own detection signals to assess the reliability of its measurement state. The phase difference detection unit utilizes the existing detection signals from the measurement process itself, without requiring external calibration signals or separate reference measurements. The system serves its own quality control needs using its inherent operational signals.
Data Source
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AI summary
An impedance measuring device outputs an alternating current of a prescribed frequency to each of a positive electrode terminal and a negative electrode terminal of a laminated type battery and detects an alternating-current potential difference between the positive electrode terminal and an intermediate-point terminal and an alternating-current potential difference between the negative electrode terminal and the intermediate-point terminal. The impedance measuring device adjusts an amplitude of the alternating current such that the alternating-current potential difference between the positive electrode terminal and the intermediate-point terminal and the alternating-current potential difference between the negative electrode terminal and the intermediate-point terminal coincide, and computes an impedance on the basis of the adjusted alternating current and alternating-current potential differences. Then, the impedance measuring device corrects a phase difference of the alternating currents output to the positive electrode terminal and the negative electrode terminal on the basis of a phase difference between an alternating-current potential generated at the positive electrode terminal and an alternating-current potential generated at the negative electrode terminal.