Lithium-Ion Battery Anode Pore Alignment for High C-Rate Charging
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Solution Overview
Problem
Lithium ion secondary batteries face decreased capacity and increased resistance during high C-rate charging due to lithium ions moving through horizontal pores in the anode active material, which can lead to lithium salt formation on the electrode surface, limiting battery performance.
Innovation Solution
An anode with an anode mixture layer oriented perpendicular to the current collector, achieved by applying a magnetic field to the anode mixture, resulting in a Z-tensor value of 0.33 or more, facilitating easier lithium ion insertion and deintercalation and improving charging/discharging efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If anode active material is oriented horizontally parallel to the current collector, then the anode mixture can be easily manufactured and applied, but lithium ion diffusion resistance increases and charging efficiency decreases at high C-rates
Solution Approach 1:
The patent changes the orientation dimension of pores from horizontal (parallel to current collector) to vertical (perpendicular to current collector). This dimensional change creates direct ion transport pathways from the electrolyte through the anode active material to the current collector, dramatically reducing diffusion distance and resistance while maintaining ease of manufacture through magnetic field alignment during the coating process
2Reliability
If anode active material is oriented vertically perpendicular to the current collector, then lithium ion diffusion resistance decreases and charging efficiency improves, but the manufacturing process becomes more complex requiring magnetic field alignment
Solution Approach 1:
The patent replaces complex mechanical alignment methods with a magnetic field-based self-alignment mechanism. During the coating process, a magnetic field is applied to align the anode active material particles vertically, and the field is then removed. This substitution simplifies the overall manufacturing complexity while achieving the desired vertical orientation for improved ion transport
Solution Approach 2:
The patent changes the physical state parameter of the anode mixture by controlling its viscosity within a specific range (5,000 to 50,000 cp). This parameter change enables the mixture to respond appropriately to the magnetic field for vertical alignment while maintaining processability, and the viscosity parameter is adjusted based on magnetic field strength and application conditions
3Quantity of substance
If high loading of anode active material is applied to increase battery capacity, then the amount of active material increases, but the distance for lithium ion transport increases significantly resulting in higher resistance
Solution Approach 1:
The patent addresses the transport distance issue by changing the pore orientation to vertical, creating direct pathways from the electrolyte interface through the high-loading anode active material layer to the current collector. This dimensional change in transport pathways allows high loading densities to be maintained without proportionally increasing ion transport resistance, as the vertical orientation provides the shortest possible diffusion paths
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
The perpendicular orientation of pores in the anode mixture layer reduces diffusion resistance and suppresses lithium salt formation, enhancing charging/discharging efficiency and rapid charging performance at high rates while maintaining capacity retention over cycles.
Implementation Method 1
a technique, in which a magnetic field is applied to orient an anode active material vertically with respect to an anode current collector
Data Source
AI summary
The present disclosure relates to an anode for a secondary battery, a method of manufacturing the anode, and a lithium ion secondary battery including the anode. An anode includes an anode mixture layer on at least one surface of an anode current collector, with pores inside the anode mixture layer having a Z-tensor value of 0.33 or more. In addition, a method of manufacturing the anode and a lithium ion secondary battery including the anode are provided.