Battery Charge Rate Control for Longer Electrochemical Cell Cycle Life
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Solution Overview
Problem
Conventional rechargeable electrochemical cell management systems result in poor longevity and performance due to short cycle life, primarily because charge and discharge rates are similar or where the charge rate is higher than the discharge rate, leading to inefficient battery usage.
Innovation Solution
Implementing an electrochemical cell management system that controls the charging and discharging rates by monitoring cell characteristics such as discharge history and morphological features, and adjusting the charging rate to be lower than the discharging rate, and inducing discharges before or after charging steps to optimize the discharge-to-charge rate ratio.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If the cell is charged at a high charging rate to reduce charging time, then the charging speed is improved, but the cycle life and longevity of the cell deteriorate
Solution Approach 1:
The charging rate is dynamically adjusted based on real-time monitoring of cell characteristics including discharge history and morphological changes. The system transitions from static charging rates to adaptive charging rates that change throughout the charging process to optimize both speed and longevity
Solution Approach 2:
The system changes the charging rate parameter during the charging process, specifically reducing the charging rate to be lower than the discharging rate for at least a portion of the charge cycle. This parameter change addresses the degradation caused by high charging rates while still providing acceptable charging performance
2Productivity
If the charging rate is increased to meet user demands for faster charging, then the charging efficiency is improved, but the morphological characteristics of the cell deteriorate
Solution Approach 1:
The system continuously monitors cell morphological characteristics and discharge history, then uses this feedback to adjust the charging rate. This closed-loop control prevents morphological degradation by adapting the charging rate based on the cell's actual state and response to previous charging cycles
Solution Approach 2:
The system induces a discharge step before the charging step to prepare the cell for charging. This preliminary action modifies the cell state beforehand, creating more favorable conditions for charging that reduce morphological degradation during the subsequent charging process
3Ease of operation
If similar charge and discharge rates are used, then the battery operation is simplified, but the cycle life is reduced
Solution Approach 1:
The system deliberately creates asymmetry between charging and discharging rates, setting the charging rate lower than the discharging rate. This asymmetric operation, while more complex than symmetric rates, significantly extends cycle life by reducing degradation during charging when the cell is most vulnerable
Data Source
AI summary
An electrochemical cell management system comprising an electrochemical cell and at least one controller configured to control the cell such that, for at least a portion of a charge cycle, the cell is charged at a charging rate or current that is lower than a discharging rate or current of at least a portion of a previous discharge cycle. An electrochemical cell management method. An electrochemical cell management system comprising an electrochemical cell and at least one controller configured to induce a discharge of the cell before and/or after a charging step of the cell. An electrochemical cell management method. An electrochemical cell management system comprising an electrochemical cell and at least one controller configured to: monitor at least one characteristic of the cell and, based on the at least one characteristic of the cell, induce a discharge and/or control a charging rate or current of the cell.