Battery Ageing Detection Using In-Vehicle Impedance Spectroscopy
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Solution Overview
Problem
Current methods for determining the ageing condition of electric vehicle batteries are inaccurate and costly, requiring complex external sensor technology, which limits their use in mobile systems.
Innovation Solution
A method that uses existing vehicle sensor technology and power electronics to acquire and analyze sinusoidal curve sections of battery operating parameters, calculating impedance and determining the ageing condition through impedance spectroscopy without external excitation, and optionally utilizing cloud computing for processing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If complex external sensor technology is used for impedance spectroscopy, then measurement precision is improved, but device complexity and cost increase
Solution Approach 1:
The patent applies universality by making the existing power electronics serve dual functions: their primary function of power conversion and their secondary function as excitation sources for impedance spectroscopy. The power electronics convert between AC and DC while simultaneously generating the sinusoidal excitation signals needed for battery impedance measurement, eliminating the need for separate external sensor technology.
Solution Approach 2:
The patent implements self-service by having the battery system's own power electronics perform the excitation function normally requiring external equipment. The power electronics generate sinusoidal test signals and measure voltage responses using existing sensors, allowing the system to self-diagnose battery ageing without external testing equipment.
2Measurement precision
If external impedance spectroscopy equipment is used, then measurement precision is improved, but ease of operation and mobility are worsened
Solution Approach 1:
The power electronics perform multiple functions including power conversion and impedance spectroscopy excitation. This multi-functionality enables accurate impedance measurement to be integrated into the vehicle's existing infrastructure, making the system easy to operate and mobile without requiring separate external equipment.
3Measurement precision
If additional excitation equipment is installed, then measurement precision is improved, but device complexity and cost increase
Solution Approach 1:
The invention makes existing power electronics perform dual functions: their primary power conversion role and their secondary role as excitation sources for impedance spectroscopy. This eliminates the need for additional expensive equipment, reducing implementation costs while maintaining measurement precision.
Solution Approach 2:
The system uses its own existing power electronics and sensors to perform impedance spectroscopy, making the system self-sufficient. This self-service approach avoids additional manufacturing costs for external testing equipment while achieving accurate battery ageing determination.
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 provides a cost-effective, accurate, and mobile means to determine the ageing condition of vehicle batteries, reducing the need for additional hardware and enabling real-time, flexible assessment during vehicle operation.
Implementation Method 1
various sinusoidal frequencies are impinged onto the current of the cells of the vehicle battery. On the basis of their voltage response, conclusions can then be drawn about the impedance of the vehicle battery or of the individual battery cells.
Data Source
AI summary
The present invention relates to a method for investigating an ageing condition of a battery (10) which is provided for power supply to an electric motor (20), comprising the steps of: determining at least one graphical progression of at least one operating parameter of the battery (10), checking the at least one graphical progression on at least one sinusoidal curve portion, if at least one sinusoidal curve portion is recognised, extracting the at least one sinusoidal curve portion, calculating an impedance of the battery (10) by means of impedance spectroscopy with reference to the at least one sinusoidal curve portion, and determining the ageing condition of the battery (10) with reference to the calculated impedance. The invention further relates to a computer program (30), a memory means, a control device (40) and a vehicle (100).