Adaptive Effective C-Rate Charging Prevents Lithium Saturation
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Solution Overview
Problem
Conventional lithium-ion battery charging methods, such as CCCV and I-V-T, either operate blindly or charge unnecessarily slowly due to over-conservative estimates, and require difficult-to-manufacture three-electrode cells, failing to adapt to changes in diffusion time caused by temperature, age, and manufacturing variations.
Innovation Solution
The Adaptive Effective C-rate Charging (AECC) method calculates an effective C-rate using battery voltage and state-of-charge, allowing for dynamic adaptation of charging current and voltage to prevent lithium surface saturation, extending battery life without needing three-electrode cell characterization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If constant-current constant-voltage (CCCV) charging method is used, then charging simplicity is maintained, but charging speed is limited due to worst-case assumptions and inability to adapt to battery characteristics
Solution Approach 1:
The patent implements feedback control by continuously monitoring battery voltage and state-of-charge, and adjusting the charging current based on the calculated effective C-rate. The controller compares the actual battery state with target values and dynamically modifies charging parameters to optimize charging speed while preventing lithium surface saturation.
Solution Approach 2:
The patent transitions from static charging parameters to dynamic parameter adjustment. The effective C-rate is continuously recalculated based on real-time battery voltage and state-of-charge measurements, allowing the charging current to adapt dynamically to changing battery characteristics during the charging process.
2Reliability
If adaptive surface concentration charging (ASCC) is used, then lithium surface saturation is prevented, but charging speed decreases due to over-conservative estimates
Solution Approach 1:
The patent changes the control parameter from conservative voltage-based estimation to effective C-rate calculation. By computing the effective C-rate based on actual battery voltage and state-of-charge, the system achieves more accurate adaptation to battery conditions, allowing faster charging while still preventing lithium surface saturation.
Solution Approach 2:
The patent replaces the mechanical/physical constraint of three-electrode cell characterization with an electrical calculation approach. Instead of requiring physical reference electrodes and complex cell construction, the effective C-rate is calculated electronically from voltage and state-of-charge measurements, achieving similar adaptive control without the manufacturing complexity.
3Measurement precision
If three-electrode cell characterization is performed, then accurate battery dynamics are obtained, but manufacturing complexity and cost increase significantly
Solution Approach 1:
The patent extracts only the essential information needed for charging control from the complex three-electrode characterization process. By calculating the effective C-rate from standard two-electrode battery measurements (voltage and state-of-charge), the system obtains the necessary battery dynamics information without requiring the insertion of reference electrodes or specialized cell construction.
Solution Approach 2:
The patent creates a mathematical model (effective C-rate calculation) that replicates the functionality of three-electrode cell characterization using readily available two-electrode measurements. This virtual model captures the essential battery dynamics without requiring physical modifications to the battery cell structure.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
AECC charges batteries quickly while preventing lithium surface saturation, adapting to temperature, aging, and manufacturing variations, and does not require complex three-electrode cell characterization, thus extending battery life and optimizing charging times.
Implementation Method 1
the net effect is dominated by a slow diffusion process for filling one electrode with lithium and another diffusion process for removing lithium from the other
Data Source
AI summary
The disclosed embodiments provide a system that manages use of a battery in a portable electronic device. During operation, the system obtains a voltage of the battery and a state-of-charge of the battery. Next, the system calculates an effective C-rate of the battery using the voltage and the state-of-charge. Finally, the system uses the effective C-rate to manage a charging process for the battery.