Lithium Ion Battery Deterioration Estimation Using Segmented Data Tables
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Solution Overview
Problem
Existing methods for estimating the deterioration degree of lithium ion secondary batteries are not accurate, leading to a discrepancy between calculated and actual deterioration, which can affect the battery's performance and lifespan.
Innovation Solution
A method involving the storage of three data tables containing relationships between temperature, State of Charge (SOC), and deterioration parameters for both positive and negative electrodes, along with lithium trapping, to calculate the battery's deterioration degree based on historical data, allowing for more precise estimation and control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a single data table method is used to estimate battery deterioration, then the calculation process is simple, but the accuracy of deterioration estimation is insufficient
Solution Approach 1:
The patent divides the battery deterioration estimation into three separate data tables: one for positive electrode deterioration, one for negative electrode deterioration, and one for lithium trapping. Each data table stores relationships between temperature, SOC, and specific deterioration parameters. This segmentation allows accurate tracking of different deterioration mechanisms while maintaining organized data structures.
Solution Approach 2:
The patent combines the results from three separate deterioration calculations (positive electrode, negative electrode, and lithium trapping) into a comprehensive battery deterioration degree. The control device integrates multiple data sources and calculation results to produce a unified deterioration assessment, achieving high accuracy through combination of specialized measurements.
2Measurement precision
If detailed temperature and SOC history is recorded and processed, then deterioration calculation accuracy improves, but computational complexity increases
Solution Approach 1:
The patent pre-calculates and stores deterioration rates in data tables during battery testing phases, organizing relationships between temperature, SOC, and deterioration parameters before actual use. This preliminary preparation allows the control device to quickly retrieve and apply pre-established relationships during operation, avoiding complex real-time calculations while maintaining high accuracy.
Solution Approach 2:
The patent uses historical temperature and SOC data as input parameters, copying past operational conditions to estimate current deterioration state. By utilizing recorded history data rather than requiring continuous complex measurements, the system achieves accurate deterioration estimation with reduced computational burden.
Data Source
AI summary
A temperature history of a lithium ion secondary battery is recorded; a SOC history of the lithium ion secondary battery is recorded; a deterioration degree (K1) of a positive electrode of the lithium ion secondary battery is calculated based on the temperature history, the SOC history, and a first data table; a deterioration degree (K2) of a negative electrode of the lithium ion secondary battery is calculated based on the temperature history, the SOC history, and a second data table; an amount of lithium trapped (TLi) in the lithium ion secondary battery is calculated based on the temperature history, the SOC history, and a third data table; and a deterioration degree of the lithium ion secondary battery is calculated based on the deterioration degree of the positive electrode, the deterioration degree of the negative electrode, and the amount of lithium trapped.