Battery Cell Screening via DRT Peak Width Analysis
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Solution Overview
Problem
Battery assemblies experience poor consistency due to manufacturing variations, leading to inconsistencies in battery cells, which deteriorate further during storage, affecting performance.
Innovation Solution
A battery device and method utilizing electrochemical impedance tests and DRT processing to determine peak width parameters in DRT spectra, ensuring feature value differences between cells are within a preset range, thereby maintaining consistency and performance during storage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If single cells are selected based on voltage, internal resistance, and capacity indicators, then initial consistency is improved, but consistency deteriorates after storage
Solution Approach 1:
The patent applies preliminary action by performing electrochemical impedance testing and DRT analysis on single cells before assembly to identify and select cells with matching relaxation time characteristics. This preliminary characterization based on peak width parameters prevents future consistency deterioration during storage, rather than relying on conventional voltage, resistance, or capacity measurements that fail to predict long-term stability.
Solution Approach 2:
The patent changes the selection parameters from conventional electrical indicators (voltage, internal resistance, capacity) to electrochemical impedance parameters, specifically the peak width parameters from DRT spectra. This parameter transformation reveals underlying electrochemical consistency that remains stable during storage, resolving the contradiction between initial selection and long-term reliability.
2Stability of the object's composition
If conventional screening methods are used, then initial consistency is improved, but manufacturing complexity increases due to additional testing
Solution Approach 1:
The patent replaces conventional mechanical/electrical testing methods (voltage measurement, resistance testing, capacity discharge) with electrochemical impedance spectroscopy and DRT analysis. This substitution provides a more fundamental characterization of cell electrochemical behavior in a single test, achieving better consistency selection without proportionally increasing manufacturing complexity.
Solution Approach 2:
The electrochemical impedance testing method serves multiple functions simultaneously: it characterizes the electrochemical state of the cell, provides relaxation time distribution information through DRT analysis, and enables consistency screening. This multi-functionality reduces the need for separate conventional tests, offsetting the added complexity with consolidated testing capability.
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
The solution ensures consistent battery cell performance by selecting cells with similar peak width parameters, maintaining excellent consistency and performance even after storage, and allows for on-line monitoring of battery health.
Implementation Method 1
performing an electrochemical impedance test on the battery cell in the state of charge
Implementation Method 2
after performing DRT processing on the obtained test data to obtain a DRT spectrum
Data Source
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AI summary
The disclosure discloses a battery device, a detection method thereof, a screening method and a screening device for a battery cell. The feature value is determined according to the peak width parameter of one of the peaks in the DRT spectrum, so based on the feature value, it is possible to reflect the difference in the relaxation time corresponding to the electrochemical process in different battery cells, and then reflect the difference in health and performance of different battery cells. In this manner, when performing screening based on the above condition, it is possible to screen battery cells with consistent health and performance, so that the consistency of the screened battery cells is better, and the performance of the battery assembly formed is excellent.