Dynamic Voltage Control for Lithium Battery SEI Layer Management
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Solution Overview
Problem
Lithium batteries face reduced lifespan due to the thickening of the solid electrolyte interface (SEI) layer during charging cycles, leading to increased impedance and reduced battery performance.
Innovation Solution
A battery management system that dynamically adjusts charging parameters, including voltage and temperature, to control SEI thickness through distinct charging methods, such as a first charging method with a lower voltage level and a second method with a higher voltage level, to manage SEI growth and maintain optimal impedance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional charging methods are used, then charging speed is maintained, but SEI layer thickness increases leading to reduced battery lifespan
Solution Approach 1:
The charging method dynamically adjusts voltage and current parameters based on real-time monitoring of charging cycles and SEI layer development stage. The system transitions from static conventional charging to dynamic adaptive charging, modifying charging parameters according to the battery's current state to prevent excessive SEI growth while maintaining efficient charging.
Solution Approach 2:
The invention changes charging parameters (voltage levels, current rates) based on the charging cycle number and detected SEI layer thickness. By adjusting these parameters dynamically, the system optimizes the balance between charging speed and SEI layer growth control, extending battery lifespan without significantly compromising charging efficiency.
2Loss of time
If high voltage charging is applied, then charging time is reduced, but SEI layer degradation accelerates
Solution Approach 1:
The charging method employs periodic alternation between different voltage levels and charging rates. High voltage charging is applied intermittently rather than continuously, allowing the SEI layer to stabilize between high-stress periods. This periodic approach reduces cumulative degradation while maintaining overall charging efficiency.
Solution Approach 2:
The system applies high voltage charging only when necessary and for limited durations, rather than maintaining maximum voltage throughout the entire charging process. By using partial high-voltage action selectively, the system achieves fast charging benefits when needed while avoiding continuous excessive stress on the SEI layer.
3Reliability
If low voltage charging is used, then SEI layer growth is controlled, but charging efficiency decreases
Solution Approach 1:
The charging system dynamically switches between low voltage and high voltage modes based on real-time conditions. During phases when SEI layer stability is critical, low voltage charging is applied to control growth. During phases when charging speed is prioritized and SEI layer is stable, high voltage charging is enabled to improve efficiency.
Data Source
AI summary
A system implements a first charging method or a second charging method during one or more charge cycles of a battery. The first charging method includes a first voltage charging level and the second charging method includes a second voltage charging level that is higher than the first charging level.