Electrochemical Impedance Measurement via Parallel Variable Impedance
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current methods for measuring electrical impedance of electrochemical devices, especially at high currents, are limited as they require additional current modulation and are difficult to implement in compact or autonomous systems, making it challenging to assess device health and efficiency effectively.
Innovation Solution
A method that involves connecting a variable impedance in parallel with the electrochemical device, allowing current subtraction from the power supply, enabling impedance measurement without additional current introduction, using a variable impedance such as MOSFET, JFET, or programmable load banks, and modulating current to determine impedance based on voltage and current measurements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If additional current is driven through the electrochemical device to measure impedance, then impedance measurement can be performed, but the system complexity and difficulty of integration increase
Solution Approach 1:
Instead of adding current to the electrochemical device to measure impedance (conventional approach), the patent inverts the approach by subtracting current through a variable impedance in parallel. This allows the electrochemical device to serve as the power source, eliminating the need for external current-driving equipment and simplifying system integration while maintaining impedance measurement capability.
Solution Approach 2:
The electrochemical device is enabled to measure its own impedance using its own output current. By connecting a variable impedance in parallel and modulating its current, the system uses the electrochemical device's inherent electrical characteristics to perform the measurement, eliminating the need for separate external current-driving equipment and reducing overall system complexity.
2Measurement precision
If external current-driving equipment is connected to the electrochemical device, then impedance can be measured, but the system becomes less suitable for compact or autonomous applications
Solution Approach 1:
The electrochemical device performs self-diagnosis by measuring its own impedance using its own output current. The variable impedance is configured in parallel with the electrochemical device, and by modulating the current through the variable impedance, the system utilizes the electrochemical device's inherent electrical characteristics to determine its impedance without requiring external current-driving equipment, making it ideal for compact and autonomous applications.
Solution Approach 2:
The variable impedance serves multiple functions: it acts as both a current modulation device and a measurement probe. By modulating the current through the variable impedance and measuring the resulting voltage and current changes, the system achieves impedance measurement capability while maintaining system compactness and autonomy.
3Device complexity
If current is subtracted from the electrochemical device via a variable impedance in parallel, then system integration is simplified, but measurement precision may be compromised
Solution Approach 1:
The system employs feedback by continuously monitoring the voltage and current through the variable impedance and using this information to calculate the impedance of the electrochemical device. The modulated current and resulting voltage measurements provide real-time feedback that enables accurate impedance determination while maintaining simplified system integration.
Solution Approach 2:
The variable impedance is modulated to change the current distribution between the parallel branches. By varying the impedance value and measuring the corresponding voltage and current changes, the system can accurately determine the electrochemical device's impedance characteristics while maintaining simple system integration through the parallel configuration.
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 efficient impedance measurement across various scales and systems, providing insights into device health and efficiency without the need for external current-driving equipment, making it suitable for high-current applications and compact systems.
Implementation Method 1
electrically connecting a variable impedance in parallel with the electrochemical device; modulating a current through the variable impedance
Implementation Method 2
electrically connecting a power supply to the electrochemical device, the power supply generating a power supply current
Implementation Method 3
measuring, at the electrochemical device, a voltage across at least a portion of the electrochemical device; and calculating, based on the measured stack current and the measured voltage, the impedance of the electrochemical device
Data Source
AI summary
The present disclosure provides methods for determining impedance of an electrochemical device by electrically connecting a variable impedance in parallel with the electrochemical device; electrically connecting a power supply to the electrochemical device, the power supply generating a power supply current; modulating a current through the variable impedance; measuring a stack current flowing through the electrochemical device; measuring, at the electrochemical device, a voltage across at least a portion of the electrochemical device; and calculating, based on the measured stack current and the measured voltage, the impedance of the electrochemical device. Systems for performing such methods are also provided.