EV Lithium Battery Anode Non-Uniform Porosity
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Solution Overview
Problem
Lithium-ion batteries in electric vehicles face degradation issues due to the growth of the solid electrolyte interface and lithium plating, leading to capacity fade and reduced lifetime, especially under fast charging conditions.
Innovation Solution
The battery cell design incorporates an anode with non-uniform porosity, where the portion adjacent to the separator has a greater porosity than the portion closer to the negative terminal, reducing internal resistance and mitigating lithium plating through a hierarchical structure and optimized porosity distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the anode has uniform porosity, then the manufacturing process is simple, but lithium plating occurs and capacity fades during fast charging
Solution Approach 1:
The anode is designed with non-uniform porosity distribution, where the porosity varies through the thickness of the anode layer. The portion adjacent to the separator has different porosity characteristics compared to the portion near the current collector, optimizing lithium ion transport and preventing lithium plating at critical interfaces while maintaining structural integrity throughout the anode.
2Reliability
If the anode porosity is increased to prevent lithium plating, then lithium ion transport is improved, but electrical conductivity decreases
Solution Approach 1:
Different regions of the anode are assigned different porosity values optimized for their specific functions. The region near the separator has higher porosity to facilitate lithium ion insertion and prevent plating, while the region near the current collector has lower porosity to maintain electrical conductivity and ensure efficient electron transport to the terminal.
Solution Approach 2:
The porosity parameter is varied continuously or in steps through the thickness of the anode layer, creating a gradient structure that optimizes the balance between ionic transport and electrical conductivity. This gradual parameter change allows the anode to adapt to different operational requirements at different locations.
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 design enhances the battery's ability to withstand fast charging with minimal degradation, improving voltage and discharge rates by reducing lithium plating and extending the battery's lifespan.
Implementation Method 1
The separator can have a first side and a second side, and can transfer ions between the first side and the second side
Data Source
AI summary
Apparatuses, systems, and methods of storing electrical energy for electric vehicles are provided. A battery pack can be disposed in an electric vehicle to power the electric vehicle. A battery cell can be arranged in the battery pack. The battery cell can include a housing. The housing can define a cavity within the housing. The cavity of the battery cell can include a separator having a first side and a second side, a cathode disposed along the first side of the separator, and an anode disposed along the second side of the separator. The anode can include a first portion adjacent to the second side of the separator, and a second portion adjacent to the first portion and separated from the separator by the first portion. A porosity of the first portion of the anode can be greater than a porosity of the second portion of the anode.