Customized Fast-Charging Algorithm for Lithium-Ion Battery Degradation
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Solution Overview
Problem
Lithium-ion battery cells experience degradation due to typical fast charging techniques, which involve high currents, temperature rise, swelling of active materials, mass transport limitations, and risks of overcharging or electrolyte decomposition, leading to reduced battery life and capacity.
Innovation Solution
An automated customized fast charging process is generated based on specific battery cell profiles, using a lookup table that provides optimal C-rates for charging, minimizing degradation by monitoring lithium plating and other undesirable effects during discharge, and applying a tailored charging protocol managed by a battery management system.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If constant current and constant voltage charging is applied to achieve fast charging, then charging speed is improved, but battery degradation increases due to higher currents, temperature rise, and chemical degradation mechanisms
Solution Approach 1:
The patent applies dynamics by transitioning from static constant current/voltage charging to dynamic charging where the C-rate is continuously adjusted based on real-time monitoring of voltage, temperature, and state of charge. The charging protocol dynamically modifies current levels to stay within safe operational boundaries while maintaining fast charging capability, thereby resolving the contradiction between charging speed and battery reliability
Solution Approach 2:
The patent changes multiple parameters simultaneously including C-rate, voltage thresholds, temperature limits, and state of charge boundaries. By dynamically adjusting these parameters based on monitored conditions, the system optimizes charging speed while preventing degradation mechanisms, thus resolving the contradiction between fast charging and battery life
2Loss of time
If higher C-rates are used for fast charging, then charging time is reduced, but chemical and mechanical degradation mechanisms are intensified
Solution Approach 1:
The patent implements feedback by continuously monitoring voltage, temperature, and state of charge during charging, then using this feedback to adjust the C-rate in real-time. This closed-loop control prevents excessive degradation by reducing current when thresholds are approached while maintaining high charging rates when conditions permit, thus resolving the contradiction between charging time and degradation
Solution Approach 2:
The patent applies beforehand cushioning by establishing pre-defined safety thresholds for voltage, temperature, and state of charge before charging begins. These thresholds act as cushioning boundaries that prevent the system from entering dangerous operational zones, allowing aggressive fast charging while preventing harmful degradation effects
3Productivity
If a customized charging algorithm is generated for each battery profile, then charging optimization is improved, but system complexity increases due to multiple testing and lookup table generation
Solution Approach 1:
The patent applies preliminary action by performing extensive battery testing and generating customized charging algorithms during the manufacturing or initialization phase. The results are stored as lookup tables that contain pre-optimized charging parameters for different battery profiles. During actual charging operations, the system simply queries these pre-generated tables, avoiding the need for complex real-time calculations and reducing operational system complexity
Solution Approach 2:
The patent uses copying by creating lookup tables that replicate optimized charging parameters for different battery profiles. Instead of performing complex real-time optimization for each charging event, the system copies pre-determined optimal parameters from the lookup tables based on the specific battery profile, thus achieving high optimization without proportional increases in system complexity
Data Source
AI summary
An automatically generated and customized fast charging process results in reduced degradation in the battery cell. An algorithm for a particular battery cell profile is automatically generated and customized to minimize degradation due to fast charging for that particular batch. To generate the custom algorithm, battery cell information is retrieved for a profile of a battery, wherein each battery profile may have a particular manufacturer, model, type, electrode batch, and potentially other specific identification information. Each battery cell is charged from a particular SOC level and at a selected C-rate, and then discharged. During discharge, the battery cell is monitored for detection of lithium plating or other undesirable effects. A lookup table is automatically generated from the battery cell information, and can be provided to devices and/or battery management systems. The BMS then uses the lookup table to apply a charging process that is customized to the on-board battery.