Battery EIS Phase Detection Using Analog Lock-In Circuitry
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Solution Overview
Problem
Conventional electrochemical impedance spectroscopy (EIS) systems for battery health assessment require significant computational resources and time due to digital processing of sampled data, especially with conventional stimulus signals ranging from mHz to kHz, leading to high memory and computational demands.
Innovation Solution
Implementing analog circuitry for synchronous acquisition of voltage and current signals associated with a battery's response, reducing the need for digital computation and enabling faster EIS analysis with lower memory requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If digital processing of sampled data is used for EIS analysis, then measurement precision is improved, but computational resources and processing time increase significantly
Solution Approach 1:
The patent replaces digital signal processing (computational system) with analog signal processing (electrical system). Specifically, it uses analog circuitry including a lock-in amplifier to directly compute impedance magnitude and phase from voltage and current signals, eliminating the need for digital sampling, storage, and computational processing while maintaining measurement precision.
Solution Approach 2:
The patent changes the processing domain from digital (discrete samples) to analog (continuous signals). By using analog multiplication and integration circuits, the system processes signals in their native continuous form, transforming the computational problem into an electrical problem that can be solved in real-time with simple circuitry.
2Measurement precision
If conventional stimulus signals (mHz to kHz) are used, then comprehensive battery health assessment is achieved, but processing time and memory requirements increase
Solution Approach 1:
The patent replaces time-consuming digital processing with instantaneous analog computation. The lock-in amplifier and analog circuitry compute impedance parameters in real-time as signals pass through the circuit, eliminating the need to store and process large amounts of sampled data, thus dramatically reducing processing time while maintaining comprehensive battery health assessment capability.
3Productivity
If analog circuitry is used for synchronous acquisition, then processing speed is improved, but device complexity in circuit design increases
Solution Approach 1:
The patent uses a lock-in amplifier, which is a universal instrument capable of measuring both magnitude and phase of AC signals simultaneously. This single device performs multiple functions (synchronous detection, filtering, and computation) that would otherwise require separate circuits, thereby achieving high processing speed while keeping the overall circuit design manageable.
4Measurement precision
If digital sampling is used, then data accuracy is improved, but physical footprint and memory requirements increase
Solution Approach 1:
The patent eliminates the need for digital memory and large-scale integration by using analog computation. The impedance measurements are derived directly from analog signals through circuit-based multiplication and integration, requiring minimal physical space for components while maintaining data accuracy through synchronous detection techniques.
Data Source
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AI summary
Systems, apparatuses, and methods for electrochemical impedance spectroscopy (EIS) for use with batteries, including for EIS phase and amplitude detection of a stimulated system are provided. A battery management system comprising EIS circuitry (510) is electrically coupled to a battery (100). The EIS circuitry (510) provides a stimulus signal (512) to the battery to generate a response signal (514) from the battery (100). A current signal and voltage signal are generated by the EIS circuitry (510) based on the response signal (514) from the battery (100). The EIS circuitry (510) generates at least one output signal (522) based on the current signal and the voltage signal, and an impedance is generated based on the at least one output signal (522).