Electrode-Based Battery Charging to Prevent Lithium Plating
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Solution Overview
Problem
Lithium plating occurs during fast charging of lithium batteries, particularly in vehicles, leading to reduced battery performance and limited usefulness due to lithium ions depositing as metallic lithium instead of intercalating, which is exacerbated by high charging currents, low temperatures, and regenerative braking.
Innovation Solution
A method and system that adjust charging currents through multiple phases with specific profiles to prevent cathode and anode potentials from exceeding thresholds, using a battery monitor and charger to manage lithium plating by monitoring and adjusting charge currents based on cathode and anode potentials.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If high charging currents are used for fast charging, then charging speed and productivity are improved, but lithium plating occurs leading to reduced battery reliability and performance
Solution Approach 1:
The charging process is divided into multiple phases with different current profiles. The charger implements a multi-stage charging strategy where the first phase uses constant current charging, the second phase transitions to constant voltage charging when the cathode potential approaches the threshold, and the third phase uses a combination of constant voltage and controlled current to prevent anode plating. This segmentation allows the system to achieve fast charging while preventing lithium plating at different stages of the charging process.
Solution Approach 2:
The charging current is dynamically adjusted based on real-time monitoring of cathode and anode potentials. The system continuously monitors electrode potentials and adjusts the charging current profile accordingly, transitioning from high current to lower current as potentials approach thresholds. This dynamic control enables the system to maintain high charging speeds when safe and reduce current when plating risk increases, resolving the contradiction between productivity and reliability.
2Speed
If lithium ion reduction rate exceeds intercalation rate during fast charging, then charging speed is improved, but lithium plating occurs as metallic lithium deposits
Solution Approach 1:
The charging system incorporates feedback control by continuously monitoring cathode and anode potentials during charging. When the cathode potential approaches the threshold where lithium plating becomes likely, the system automatically adjusts the charging current to maintain the potential below the threshold. Similarly, when anode potential indicates risk of plating, the current is reduced. This feedback mechanism ensures that lithium ion reduction rate is kept in balance with intercalation rate, preventing metallic lithium deposition while maintaining efficient charging.
3Use of energy by moving object
If charging is performed at low ambient temperatures, then energy efficiency is improved, but lithium ion movement slows causing increased plating risk
Solution Approach 1:
The system adjusts charging parameters based on ambient temperature conditions. At low temperatures, the charging current profile is modified to account for reduced lithium ion mobility. The system uses temperature-compensated charge profiles that reduce current magnitude and extend charging time at low temperatures, preventing plating while maintaining energy efficiency. The parameter changes include adjusting current thresholds, modifying charge profiles, and extending charging duration to match the reduced ion transport rates at lower temperatures.
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
Effectively minimizes lithium plating by controlling charging currents, maintaining optimal battery performance and extending the battery's useful life by preventing undesirable voltage potentials during fast charging.
Implementation Method 1
not all lithium entering host material may be accommodated to a suitable intercalated form (e.g., an LiC6 intercalation form for a host material comprising graphite) such that lithium plating may occur
Implementation Method 2
lithium plating may occur. The plating may result from lithium ions (e.g., Li+) depositing as metallic lithium when the conditions are such that lithium ion reduction is preferential to lithium intercalation
Data Source
AI summary
A method for controlling charging of a battery to minimize or avoid lithium plating. The method may include charging the battery during with a first charge current having a first charge profile, monitoring charging of the battery with the first charge current, and thereafter charging the battery with a second charge current having a cathode charge profile to prevent a cathode potential of the battery from exceeding a cathode threshold.