Layered Negative Electrode Current Collector for Li-Al Corrosion Blocking
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Solution Overview
Problem
Current composite current collectors for lithium-ion batteries face issues such as large mass, low mechanical strength, easy detachment, susceptibility to corrosion, and low conductivity, which hinder their ability to meet the demands for thinner, lighter, and more conductive negative electrode requirements.
Innovation Solution
A negative electrode current collector is designed with a specific layered structure comprising a barrier layer, conductive layers, and a polymer layer, along with optional intermediate and bonding layers, to enhance corrosion resistance, electrochemical stability, and conductivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional copper foil is used as negative electrode current collector, then good conductivity and electrochemical stability are achieved, but weight and cost increase
Solution Approach 1:
The patent employs a composite current collector structure consisting of a polymer substrate layer combined with metal foil layers (aluminum and/or copper). This composite design allows the structure to leverage the lightweight advantage of polymers while incorporating metal layers that provide necessary conductivity and electrochemical stability, thereby reducing overall weight while maintaining performance requirements.
2Weight of moving object
If aluminum foil is used as negative electrode current collector, then weight is reduced, but galvanic corrosion and alloying with lithium occur
Solution Approach 1:
The patent introduces an intermediate layer between the aluminum foil and the electrode slurry. This intermediate layer acts as a mediator that prevents direct contact between aluminum and lithium, thereby avoiding galvanic corrosion and alloying reactions. The intermediate layer allows the lightweight aluminum substrate to be used while protecting it from harmful electrochemical reactions.
Solution Approach 2:
The patent extracts the problematic direct interaction between aluminum and lithium by separating them with an intermediate protective layer. This extraction of the harmful contact interface allows the aluminum foil to retain its weight advantage while eliminating the corrosion and alloying issues that would otherwise occur.
3Weight of moving object
If composite current collectors are developed to reduce weight, then weight and thickness are reduced, but mechanical strength and conductivity decrease
Solution Approach 1:
The patent designs a composite structure where a polymer substrate is combined with metal foil layers. The polymer provides lightweight properties and flexibility, while the metal foil layers (particularly copper) contribute mechanical strength and electrical conductivity. This composite approach allows simultaneous optimization of weight and mechanical properties.
Solution Approach 2:
The patent merges the advantages of different materials by combining polymer and metal components into a unified current collector structure. The polymer substrate provides lightweight foundation while metal layers are integrated to reinforce mechanical strength and enhance conductivity, achieving a synergistic effect that overcomes the limitations of individual materials.
4Reliability
If conductive layers are added to improve conductivity, then conductivity increases, but structure becomes more complex and manufacturing difficulty increases
Solution Approach 1:
The patent designs metal foil layers that serve multiple functions simultaneously: they provide electrical conductivity, contribute mechanical strength, and act as protective barriers. By making these layers multi-functional, the need for separate dedicated conductive layers is reduced, thereby limiting the increase in structural complexity while still achieving improved conductivity.
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 layered structure improves the safety and conductivity of the negative electrode, reduces galvanic corrosion, and enhances the cycle life of lithium-ion batteries, offering better performance and resource efficiency.
Implementation Method 1
arranging a barrier layer I and a barrier layer II, can block the formation of Li—Al alloy and improve the conductivity of the negative electrode current collector
Implementation Method 2
a negative electrode current collector, which includes a barrier layer I, a conductive layer I, a polymer layer, a conductive layer II, and a barrier layer II in sequence
Implementation Method 3
by arranging an intermediate layer I and an intermediate layer II, can mitigate the galvanic corrosion tendency and alloying degree between copper and aluminum
Data Source
AI summary
In a lithium-ion battery, a negative electrode current collector includes a barrier layer I, a conductive layer I, a polymer layer, a conductive layer II, and a barrier layer II in sequence. For the negative electrode current collector, barrier layer I and barrier layer II are continuous and dense film structures, which can prevent the conductive materials in conductive layer I and conductive layer II from alloying, improve the conductivity of the current collector, and replace traditional copper as a negative electrode current collector. It is suitable for industrial promotion with advantages of low production cost, good corrosion resistance, electrochemical stability, thin thickness, light weight, low conductivity, and high safety.