Battery Capacity Estimation Using Timed AC Impedance Windows
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing methods for estimating the capacity of secondary batteries using alternating current impedance measurement techniques often result in variations, leading to inaccurate capacity estimation, especially due to the elapsed time after charging and discharging until the impedance is measured.
Innovation Solution
A battery capacity estimation method that involves charging and discharging a secondary battery, acquiring alternating current impedance measurements within a specific time frame (longer than a minimum waiting time and shorter than a maximum waiting time) to improve accuracy, and utilizing a pre-trained neural network model for estimating battery capacity based on Nyquist plots.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If alternating current impedance measurement is performed at any time after charging and discharging, then measurement can be conducted flexibly, but measurement precision deteriorates due to variations in estimation results
Solution Approach 1:
The patent changes the time parameter by defining a specific measurement window (between minimum and maximum waiting times after charging/discharging completion) to optimize measurement precision. This parameter control ensures that impedance measurements are taken when the battery is in a stable state, reducing variations in estimation results while maintaining operational flexibility within the defined window.
2Loss of time
If alternating current impedance measurement is performed immediately after charging and discharging, then measurement time is reduced, but measurement precision deteriorates due to larger variations in estimation results
Solution Approach 1:
The patent applies preliminary action by requiring the battery to rest for a minimum waiting time after charging/discharging before impedance measurement. This preliminary rest period allows the battery to reach a stable state, ensuring measurement precision is not compromised while minimizing the waiting time through experimentally determined optimal values.
Solution Approach 2:
The patent optimizes the waiting time parameter by establishing both minimum and maximum boundaries. The minimum waiting time ensures sufficient stabilization, while the maximum prevents excessive delays. This parameter optimization balances measurement time loss against measurement precision, achieving the best compromise through experimental determination of optimal time values.
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 enhances the accuracy of battery capacity estimation by minimizing variations in measurement results and optimizing the neural network model for precise capacity determination.
Implementation Method 1
acquiring a measurement result of an alternating current impedance of the target secondary battery by applying an alternating current signal within a specific frequency range to the target secondary battery
Data Source
AI summary
A battery capacity estimation system executes a charging and discharging process (S1), an alternating current impedance acquiring process (S2 and S3), and a battery capacity estimating process (S4 to S6). The charging and discharging process involves charging and discharging a target secondary battery. The alternating current impedance acquiring process involves acquiring a measurement result of an alternating current impedance of a target secondary battery, by applying an alternating current signal within a specific frequency range to the target secondary battery after completion of the charging and discharging in the charging and discharging process and before a predetermined maximum waiting time elapses. The battery capacity estimating step involves estimating a battery capacity of the target secondary battery based on the measurement result of the alternating current impedance.