Battery Impedance Diagnosis with Temperature and Aging Correction
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Solution Overview
Problem
Current battery maintenance methods for railway environments are inefficient and unsafe due to the high number of batteries, varying environmental conditions, and inability to account for temperature and aging effects, leading to increased maintenance time and cost, as well as reduced reliability and safety.
Innovation Solution
A method for predictive maintenance that measures the absolute impedance of battery modules, using correction algorithms to account for temperature and aging, allowing for trend analysis and reducing the need to access individual cell terminals, thereby improving safety and efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If impedance measurement is performed on each individual cell of every battery, then diagnostic precision is improved, but maintenance time increases significantly
Solution Approach 1:
The battery system is segmented into modular units (battery assemblies, each containing multiple cells). Instead of measuring every individual cell across all batteries, the method measures impedance at the battery assembly level, where each assembly represents a functional segment. This segmentation allows diagnostic information to be obtained at a higher level of organization, reducing the number of measurement points from individual cells to battery assemblies while maintaining diagnostic capability.
Solution Approach 2:
Multiple cells within a battery assembly are electrically connected in series or parallel, forming a combined measurement unit. The impedance measurement is performed on the combined battery assembly rather than on individual cells separately. This merging approach consolidates multiple measurement targets into a single measurement point, significantly reducing the time required while preserving the ability to detect degradation trends through the collective impedance behavior of the assembly.
2Measurement precision
If impedance measurement is performed on each individual cell, then diagnostic accuracy is improved, but operator safety deteriorates due to increased exposure to battery terminals
Solution Approach 1:
The measurement approach is segmented from the cell level to the battery assembly level. By performing measurements at the assembly level rather than individual cell level, the number of terminal access points is reduced. This segmentation minimizes operator exposure to potentially hazardous battery terminals while maintaining the ability to detect degradation through impedance trends of the entire assembly.
Solution Approach 2:
The battery assembly serves multiple functions: it acts as both the operational power source and the measurement unit. By measuring impedance at the assembly level, the same structural unit that provides electrical function also serves as the diagnostic interface, eliminating the need for separate cell-level access and reducing safety risks associated with repeated terminal exposure.
3Ease of operation
If standard impedance measurement methods are used in railway environments, then measurement simplicity is maintained, but measurement precision deteriorates due to temperature variations and aging effects
Solution Approach 1:
Temperature correction factors and aging compensation algorithms are pre-calculated and stored in the system before actual measurements are taken. When performing impedance measurements in the field, the system automatically applies these pre-prepared corrections based on measured temperature and battery age, eliminating the need for complex real-time calculations or controlled environmental conditions during measurement.
Solution Approach 2:
The measurement system dynamically adjusts the impedance evaluation criteria based on changing parameters such as temperature and battery age. Instead of using fixed threshold values, the system modifies the reference impedance values and correction factors according to the actual operating conditions, allowing accurate diagnostics across varying environmental conditions without requiring controlled measurement environments.
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 significantly reduces maintenance time, enhances operator safety, and enables effective predictive maintenance by providing accurate, temperature- and aging-corrected impedance measurements, allowing for proactive replacement of batteries and minimizing downtime.
Implementation Method 1
the measurement of the impedance of groups of cells or modules of the batteries
Implementation Method 2
in which the effect of the temperature is furthermore taken into account
Data Source
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AI summary
The invention relates to a method for diagnosing batteries in dynamic environments which allows assuring high battery reliability for implementing a predictive maintenance plan, and which basically comprises the steps of measuring the impedance of groups of cells or modules of the batteries, subsequently applying a correction of said impedance as a function of temperature and then a correction which takes into account the effect that the ageing of the batteries has on said modules or groups of cells.