Lithium-Ion Battery Charging Controller Using Kalman Filter
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Solution Overview
Problem
Lithium plating during charging of lithium-ion batteries is difficult to analyze and prevent, leading to reduced battery life and safety concerns, as existing charging methods rely on conservative approaches that compromise charging speed.
Innovation Solution
A battery charging controller based on a Kalman filter and a physics-based battery cell model dynamically adjusts the charge current using feedback metrics from state estimators, such as polarization resistance and electrolyte overpotential, to minimize lithium plating.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conservative charging methods are used, then battery safety is improved, but charging speed deteriorates
Solution Approach 1:
The patent applies dynamics by transitioning from static conservative charging limits to dynamic charge current adjustment. The system continuously monitors battery state (temperature, charge level, internal resistance) and adapts the charge current in real-time, allowing maximum safe charging speed at each moment rather than using fixed conservative limits throughout the charging process.
Solution Approach 2:
The patent implements feedback control by monitoring battery parameters (temperature, voltage, current, internal resistance) and using this information to adjust the charge current. The controller receives feedback from the battery state and modifies the charging profile accordingly, enabling both safety and optimized charging speed through closed-loop control.
2Productivity
If high charge current is applied, then charging speed is improved, but lithium plating increases
Solution Approach 1:
The patent applies preliminary action by predicting lithium plating risk before it occurs. The system uses state estimators and models to forecast the likelihood of lithium plating based on current battery conditions and planned charge current, allowing preventive adjustment of charging parameters before harmful plating can occur.
Solution Approach 2:
The patent replaces direct mechanical/chemical monitoring of lithium plating with electrical parameter monitoring and modeling. Instead of detecting actual lithium deposits (which would require complex physical analysis), the system substitutes this with monitoring of electrical parameters (voltage, current, impedance) and using mathematical models to infer plating risk, enabling indirect but effective control.
3Object-generated harmful factors
If charge current is reduced to prevent lithium plating, then lithium plating is minimized, but charging time increases
Solution Approach 1:
The patent applies periodic action by using pulsing or variable charge current profiles rather than continuous constant current. The system periodically adjusts charge current based on real-time battery state assessment, applying higher current when safe and reducing it when plating risk increases, creating a rhythmic charging pattern that optimizes both safety and time efficiency.
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
This solution enables more efficient and safer charging by continuously monitoring and adapting to the battery's state, allowing for faster charging while reducing lithium plating and enhancing battery longevity.
Implementation Method 1
investigation of 'lithium plating', which occurs during certain charging conditions and can be detrimental to battery life and safety
Data Source
AI summary
A method of controlling the charge current during charging of a lithium-ion battery. A battery charging controller is based on a Kalman filter, which uses estimated battery states to generate a feedback metric to continually adjust a battery cell model. The battery cell model then delivers data to an optimization process that generates the charge current.