Li-Ion Fast-Charging Control Using Current-Change Detection
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Solution Overview
Problem
Existing battery health monitoring algorithms in fast-charging systems are dependent on variable battery conditions, making real-time SOH adjustment difficult and leading to potential degradation, necessitating a more effective real-time battery health degradation detection mechanism.
Innovation Solution
A system with a battery charging circuit that controls a charging voltage waveform and a detection circuit to monitor the rate of change of charging current, adjusting the waveform to prevent degradation by using piece-wise constant voltage profiles based on battery temperature, SOC, and SOH.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If CCCV charging pattern is used, then charging speed is improved, but battery health degradation occurs
Solution Approach 1:
The patent applies dynamics by transitioning from static CCCV charging to dynamic piece-wise constant voltage charging. The charging voltage is adjusted in multiple stages based on real-time battery state (temperature, SOC, SOH), allowing the system to optimize charging speed while preventing health degradation at different charging phases
Solution Approach 2:
The patent changes the voltage parameter dynamically during charging. Instead of maintaining constant voltage, the system uses piece-wise constant voltage profiles where voltage levels are adjusted based on battery conditions. This parameter change enables faster charging when battery health is good while reducing voltage stress when degradation risks increase
2Measurement precision
If physics-based model is used for charging control, then charging pattern accuracy is improved, but real-time adaptation difficulty increases
Solution Approach 1:
The patent segments the charging process into multiple voltage stages, each with its own constant voltage level. This segmentation simplifies real-time control by breaking down the complex PBM into manageable voltage steps, where each stage can be controlled independently based on battery state feedback
Solution Approach 2:
The patent performs preliminary action by pre-calculating piece-wise constant voltage profiles based on offline PBM studies. These pre-determined voltage patterns are stored and applied during charging, eliminating the need for complex real-time PBM calculations while maintaining accuracy through real-time state monitoring
3Ease of manufacture
If offline charging patterns are used, then implementation simplicity is improved, but real-time health monitoring capability deteriorates
Solution Approach 1:
The patent implements feedback by continuously monitoring battery temperature, SOC, and SOH during charging and using this information to adjust the piece-wise constant voltage profile. This feedback mechanism enables real-time health monitoring while maintaining the simplicity of pre-determined voltage patterns, as the system adapts based on actual battery state
Data Source
AI summary
A system detects degradation of battery health due to fast-charging and controls charging of the battery and/or provides indications of battery health while fast-charging. The system includes remove a battery charging circuit that controls a charging voltage waveform to supply charging current to a battery and a detection circuit that monitors a rate of change of the charging current and controls the charging voltage waveform responsive to an output of the detection circuit.