Battery Charging Control Using SOC-Dependent Lithium Plating Estimation
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Solution Overview
Problem
Lithium ion batteries in electric vehicles face degradation due to lithium plating on anodes during charging, which is not effectively addressed by traditional current limits that are often overly conservative and inefficient, especially under pulsed charging conditions.
Innovation Solution
A battery management system utilizing an electrochemical model to dynamically control charging parameters based on monitored parameters like temperature, state of charge, and charging current, preventing lithium plating by determining and quantifying plating kinetics and adjusting charging operations accordingly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional current limits are applied to prevent lithium plating, then battery reliability is improved, but charging productivity deteriorates due to overly conservative limits
Solution Approach 1:
The patent implements dynamic current limiting that adjusts charging current based on real-time battery state parameters (temperature, state of charge, charge rate). Instead of applying fixed conservative current limits throughout charging, the system dynamically modulates current to prevent lithium plating only when conditions indicate risk, thereby maintaining higher productivity while ensuring reliability.
Solution Approach 2:
The system changes operating parameters (current, voltage, temperature compensation) based on battery state to optimize both safety and charging speed. By monitoring parameters like cell temperature, state of charge, and charge rate, the system adjusts current limits to prevent plating at critical states while allowing faster charging when conditions are safe, resolving the contradiction between reliability and productivity.
2Reliability
If conservative current limits are enforced to prevent lithium plating, then battery degradation is reduced, but charging time increases
Solution Approach 1:
The system performs preliminary assessment of battery conditions (temperature, state of charge, charge rate) before applying current limits. By predicting plating risk based on current battery state and charging conditions, the system proactively adjusts current only when necessary, preventing plating before it occurs while avoiding unnecessary current reductions that would extend charging time.
Solution Approach 2:
The patent employs dynamic current adjustment that responds to real-time battery conditions. The system transitions from static conservative limits to dynamic modulation, increasing current when battery conditions are favorable and reducing current only when plating risk is detected, thereby minimizing charging time while protecting battery longevity.
3Productivity
If high charging current is applied to improve productivity, then charging speed increases, but lithium plating occurs on anodes
Solution Approach 1:
The system continuously monitors battery parameters (temperature, state of charge, charge rate, cell voltage) and uses this feedback to adjust charging current in real-time. When monitoring indicates conditions favorable for plating (high SOC, low temperature, high charge rate), the system reduces current to prevent plating. When conditions are safe, the system allows higher current for faster charging, thus achieving high productivity without generating harmful plating.
Solution Approach 2:
The patent dynamically changes charging parameters (current magnitude, voltage limits, temperature compensation) based on real-time battery state. By adjusting these parameters according to conditions like temperature and state of charge, the system enables high-current fast charging when safe while preventing plating when conditions deteriorate, resolving the contradiction between charging speed and plating prevention.
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 approach maximizes battery performance while preventing lithium plating and related aging, providing more accurate current limits for pulsed charging regimes and maintaining efficient charging operations.
Implementation Method 1
determines lithium plating reaction kinetics at an anode of the lithium ion battery, determines a quantity of plated lithium at the anode
Data Source
AI summary
A battery system includes a lithium ion battery configured to couple to an electrical system, and a battery management system configured to electrically couple to the lithium ion battery and to control one or more recharge parameters of the lithium ion battery. The battery management system is programmed with an electrochemical model, and the battery management system is configured to monitor parameters of the lithium ion battery, and to control the one or more recharge parameters of the lithium ion battery based on the electrochemical model and the one or more monitored parameters. The electrochemical model determines lithium plating reaction kinetics at an anode of the lithium ion battery, determines a quantity of plated lithium at the anode of the lithium ion battery, or both, and indicates a relationship between the one or more monitored parameters and the lithium plating reaction kinetics, the quantity of plated lithium, or both.