Dynamic Lithium-Ion Battery Charging Control
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Solution Overview
Problem
Current fast charging methods for lithium-ion batteries, such as CC-CV, can damage batteries due to large currents, leading to accelerated aging and reduced lifetime, as they do not consider the internal constraints and kinetic limitations of the battery during the charging process.
Innovation Solution
An electrochemical battery system utilizing optimal control theory to predict and adjust current and voltage inputs based on internal state parameters, ensuring constraints are not exceeded, thereby implementing a time-optimal charging solution that reduces charging time by 50% compared to conventional methods.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If standard charging techniques such as CC-CV are used for fast charging, then charging speed is improved, but battery damage and accelerated aging occur due to large currents
Solution Approach 1:
The patent implements dynamic current adjustment during charging by continuously monitoring internal battery state parameters (temperature, voltage, current) and adapting the charging current in real-time. This replaces static CC-CV charging with a dynamic profile that maximizes charging speed while preventing damage by reducing current when internal constraints are approached, thus resolving the contradiction between charging speed and battery lifetime
Solution Approach 2:
The system employs feedback control by measuring internal battery state parameters during charging and using this information to adjust the charging current. The controller continuously monitors temperature, voltage, and current, and modifies the charging profile based on these measurements to prevent battery damage while maintaining fast charging performance, thereby resolving the contradiction between productivity and reliability
2Loss of time
If large currents are passed through the battery during fast charging, then charging time is reduced, but overpotentials and mechanical stress increase causing battery damage
Solution Approach 1:
The patent performs preliminary assessment of battery internal constraints before applying high current by evaluating initial state parameters (temperature, voltage, SOC). Based on this preliminary evaluation, the system pre-determines an appropriate charging current profile that avoids excessive overpotentials and mechanical stress from the outset, thus reducing charging time without causing battery damage
Solution Approach 2:
The system dynamically changes charging parameters (current magnitude, voltage limits) based on real-time monitoring of internal battery state. By adjusting these parameters according to actual battery conditions rather than using fixed high current, the system achieves fast charging while maintaining stress levels within safe boundaries, resolving the contradiction between charging time and harmful factors
3Reliability
If voltage limits are set conservatively for all batteries, then battery safety is maintained, but charging performance is suboptimal for new and aged batteries with different behaviors
Solution Approach 1:
The patent applies local quality by tailoring charging parameters to the specific state and characteristics of each battery (new vs. aged, current temperature, SOC level). Instead of using uniform conservative voltage limits for all batteries, the system adjusts voltage and current limits according to individual battery conditions, thereby maintaining safety while optimizing charging performance for each specific case
4Device complexity
If conventional charging strategies are used, then implementation simplicity is maintained, but maximum performance determined by electrochemistry is not achieved
Solution Approach 1:
The patent replaces simple mechanical switching of charging modes (CC-CV) with an intelligent control system that uses sensors, processors, and algorithms to optimize charging. This substitution of mechanical/simple control with electronic/intelligent control enables achievement of maximum electrochemical performance while managing the increased complexity through integrated battery management system architecture
Data Source
AI summary
In one embodiment, an electrochemical battery system performs optimized charging of a battery. The electrochemical battery system includes at least one electrochemical cell, a memory storing command instructions, and a controller operably connected to the memory and a current source. The controller executes the command instructions to generate a first prediction of at least one state parameter corresponding to an internal state of the at least one electrochemical cell in the event that a first input current is applied to the at least one electrochemical cell for a predetermined time based upon a present state of the at least one state parameter in the electrochemical cell, determine a second input current based on the first prediction and at least one predetermined state parameter constraint, and control the current source to apply the second input current to the at least one electrochemical cell.