Battery Module EIS Testing With Autonomous Monitoring Electronics
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Solution Overview
Problem
Conventional methods for testing battery modules after creation do not typically include electrical impedance spectroscopy (EIS), which is essential for evaluating the electrical properties of batteries. This lack of EIS testing hinders the identification of bad battery units and limits advancements in battery technology.
Innovation Solution
A device and method that utilize autonomous monitoring electronics attached to battery modules to conduct EIS measurements. The method involves applying a stimulus to the battery module, allowing it to relax, and then recording signals using the monitoring electronics. This approach allows for efficient, high-volume testing of battery modules and continued monitoring during storage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional voltage measurement and storage methods are used to identify bad battery units, then the testing process is simple, but the measurement precision and reliability are insufficient
Solution Approach 1:
The patent introduces an AC stimulus signal as an intermediary to probe the battery's electrochemical properties. This stimulus signal enables precise measurement of impedance characteristics without requiring complex storage and comparison procedures, directly improving identification accuracy through electrical property measurement rather than voltage change observation
Solution Approach 2:
The patent replaces the mechanical/time-based storage method (storing batteries for weeks and remeasuring voltage) with an electrical measurement approach (EIS). This substitution eliminates the need for long-term storage infrastructure and manual remeasurement processes, achieving comparable or superior identification accuracy through electrical impedance spectroscopy
2Reliability
If EIS testing is not performed after module creation, then the testing process is fast and simple, but the reliability of battery quality assessment deteriorates
Solution Approach 1:
The patent performs EIS testing immediately after module creation as a preliminary quality gate. By conducting the stimulus-based impedance measurement at this early stage, the system ensures reliable quality assessment without requiring subsequent long-term storage and remeasurement, thus maintaining high productivity while improving reliability
Solution Approach 2:
The patent measures multiple impedance parameters across different frequencies to assess battery quality. By analyzing the frequency-dependent impedance characteristics (real and imaginary components), the system achieves comprehensive quality assessment in a single testing session, improving reliability without requiring multiple tests over time
3Measurement precision
If AC stimulus signal is applied to measure impedance, then the measurement precision improves, but the device complexity and energy consumption increase
Solution Approach 1:
The patent applies periodic AC stimulus signals at multiple frequencies to measure impedance characteristics. By using sinusoidal waveforms with controlled amplitudes and frequencies, the system achieves precise impedance measurement through periodic excitation and response analysis, minimizing energy consumption through efficient signal cycling rather than continuous high-power input
Solution Approach 2:
The patent applies small-amplitude AC stimulus signals that are sufficient to elicit measurable impedance responses without excessive energy input. By using low-voltage or low-current AC probes rather than full-power DC testing, the system achieves adequate measurement precision with minimal energy consumption, avoiding the need for high-energy discharge tests
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 efficient and high-volume testing of battery modules, allowing for the identification of bad units and providing valuable data for battery health assessment, state of charge, and state of health. This leads to improved battery technology and application by ensuring better quality control and monitoring capabilities.
Implementation Method 1
Electrical impedance spectroscopy (EIS) is a measurement of electrochemical impedance. Electrochemical impedance is usually measured by applying an AC (alternating current) signal, such as a sinusoidal test voltage or current, to an electrochemical cell under test and then measuring the current through the electrochemical cell. EIS uses measurement of impedance over a suitable frequency range.
Data Source
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AI summary
Testing of a battery module can be conducted using monitoring electronics attached to the battery module. Stimulus can be applied to the battery module and removed. After removal of the stimulus, the monitoring electronics can collect signals from the monitoring electronics reflecting parameters of the battery module as it relaxes back to a non-stimulated state. The stimulus can be provided by test equipment or by components of a system in which the battery module, having attached monitoring electronics, is implemented. The monitoring electronics attached to the battery module can provide autonomous recording of signals associated with the battery module that can provide data regarding the status of the battery module or one or more batteries contained in the battery module.