Magnetic-Field Fast Charging for Graphite Anode Li-Ion Batteries
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Solution Overview
Problem
Lithium-ion batteries with graphite anodes suffer from severe performance degradation during fast charging due to the formation of a solid-electrolyte interface (SEI) and lithium plating, leading to capacity loss, poor columbic efficiency, and safety risks from thermal runaway.
Innovation Solution
Applying a magnetic field during fast charging to control lithium ion flux using magnetohydrodynamic forces, reducing degradation by positioning permanent or electromagnets to align magnetic field lines with the direction of ion transport towards the anode.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If fast charging is applied to lithium-ion batteries with graphite anodes, then charging speed is improved, but severe performance degradation occurs due to SEI formation and lithium plating
Solution Approach 1:
The patent applies an external magnetic field as a new parameter to alter the charging process. This magnetic field parameter changes the transport behavior of lithium ions, enabling faster charging while suppressing harmful side reactions like SEI formation and lithium plating that normally occur during rapid charging.
Solution Approach 2:
The magnetic field acts as an intermediary that mediates between the charging current and the lithium ion transport process. By introducing this intermediate magnetic field, the patent enables controlled ion flux distribution that prevents direct contact between excessive lithium ions and the graphite anode surface, thereby reducing degradation during fast charging.
2Loss of time
If conventional fast charging is used, then charging time is reduced, but capacity loss increases due to irreversible SEI formation
Solution Approach 1:
The magnetic field parameter modifies the charging process to reduce irreversible lithium consumption. By applying the magnetic field during fast charging, the patent changes ion transport dynamics to minimize SEI formation, thereby preserving active lithium and reducing capacity loss despite the reduced charging time.
3Productivity
If fast charging increases ionic flux, then charging rate is improved, but non-uniform distribution causes lithium plating and film fracture
Solution Approach 1:
The magnetic field creates local variations in ion flux distribution across the anode surface. By positioning magnets to generate specific field patterns, the patent achieves more uniform local lithium deposition, preventing localized concentration spikes that lead to plating and film fracture while maintaining high overall charging rates.
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
Reduces deleterious degradation, improves capacity and columbic efficiency, and minimizes safety risks by homogenizing lithium distribution and suppressing film fracture.
Implementation Method 1
Applying a magnetic field during fast charging to control lithium ion flux using magnetohydrodynamic forces
Data Source
AI summary
Fast charging of a lithium-ion battery at 4C rate or 5C rate or more is improved by applying an external magnetic field relative to the battery to establish magnetic field lines that extend in a direction of primary movement of lithium ions toward the graphite anode during fast charging. Deleterious degradation of the graphite anode from repeated fast charging can be reduced or eliminated by practice of the invention.