Multilayer Battery Electrode Stair Structure for Capacity Ratio Control
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Solution Overview
Problem
Existing electrodes for lithium secondary batteries face issues with degradation of durability and performance due to excessive thickness of single electrode active material layers, and multilayer structures suffer from decreased capacity and lithium deposition when sloped portions are not adequately controlled.
Innovation Solution
The electrode features a multilayer structure with sloped portions at the ends of each sublayer, forming a stair-like shape, ensuring a controlled capacity ratio between positive and negative electrodes by maintaining specific thickness differences and uncoated regions, achieved through precise coating and drying processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a current collector is used in a lithium secondary battery, then electrical conductivity and structural support are improved, but dendrite formation occurs during charging/discharging cycles
Solution Approach 1:
An aluminum oxide coating layer is applied to the aluminum current collector to serve as an intermediary barrier. This coating prevents direct contact between the aluminum and electrolyte, thereby preventing dendrite formation while maintaining electrical conductivity through controlled ion transport.
Solution Approach 2:
The aluminum oxide coating is formed with controlled porosity through anodization processing. The porous structure allows lithium ion transport while providing physical barriers against dendrite penetration, combining ion conductivity with dendrite prevention functionality.
2Ease of manufacture
If aluminum current collector is used to reduce cost, then manufacturing cost is reduced, but corrosion resistance and dendrite prevention are insufficient
Solution Approach 1:
The current collector is constructed as a composite structure with an aluminum base layer providing cost-effectiveness and electrical conductivity, overlaid with an aluminum oxide coating providing corrosion resistance and dendrite prevention. This composite approach combines the advantages of different materials while mitigating their individual disadvantages.
Solution Approach 2:
The aluminum oxide coating thickness and porosity are controlled through anodization parameters (voltage, time, electrolyte composition) to optimize the balance between cost, corrosion resistance, and dendrite prevention performance.
3Reliability
If copper current collector is used instead of aluminum, then electrochemical stability is improved, but manufacturing cost increases
Solution Approach 1:
The invention uses aluminum, a cheaper material, as the current collector base and relies on the in-situ formed aluminum oxide coating to provide the electrochemical stability traditionally associated with copper. This replaces expensive copper with a cost-effective aluminum-based solution.
4Ease of manufacture
If aluminum current collector is used for cost reduction, then manufacturing cost decreases, but dendrite generation during charging/discharging increases
Solution Approach 1:
The aluminum oxide coating serves as an intermediary barrier between the aluminum current collector and the electrolyte, preventing direct interaction that would lead to dendrite formation. The coating allows controlled ion transport while blocking dendrite growth pathways.
Solution Approach 2:
The aluminum oxide coating is pre-formed on the aluminum current collector before battery assembly through anodization treatment. This preliminary surface modification ensures dendrite prevention capability is built-in from the start, eliminating the need for additional protective layers.
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 processing efficiency and controls the capacity ratio, improving electrode performance and preventing lithium deposition, thereby enhancing battery durability and capacity.
Implementation Method 1
it has been proposed to form an aluminum oxide coating layer on a surface of an aluminum current collector by anodization treatment
Implementation Method 2
the aluminum oxide coating layer prevents direct contact between the aluminum current collector and electrolyte
Implementation Method 3
the aluminum oxide coating layer has a porous structure, and thus it is possible to transport lithium ions smoothly while preventing formation of dendrites
Data Source
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AI summary
Provided is an electrode for an electrochemical device. The electrode has a multilayer structure, and the electrode end portion has a stair-like structure due to the areal difference of each layer, thereby facilitating control of the capacity ratio of the positive electrode to the negative electrode. In terms of the electrode processing, the process for manufacturing an electrode including formation of a stair-like structure provides higher processing efficiency as compared to the process of accurately matching the ends of the electrodes. Therefore, when controlling the electrode manufacturing process to realize a multilayer electrode having an adequate stair width that is not excessively out of range, it is possible to enhance the processing efficiency and to control the capacity ratio of the resultant electrode.