Thick Lithium Battery Electrode Crack Prevention
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Solution Overview
Problem
Rechargeable lithium batteries face issues with surface cracks in thick positive and negative electrodes, leading to poor conductivity and reduced performance, which affects their capacity and efficiency.
Innovation Solution
A positive electrode is designed with a net-type current collector and a positive active material layer containing a binder and conductive material, hot-pressed to a thickness of 150 μm or more, enhancing adherence and conductivity while minimizing cracks, and a rechargeable lithium battery is constructed with this electrode, a negative electrode, and a separator.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the positive and negative electrodes are made thick to achieve large capacity, then the battery capacity increases, but cracks develop on the surface leading to poor conductivity
Solution Approach 1:
The invention changes the physical and chemical parameters of the electrode structure by incorporating conductive materials and optimizing binder content. This allows thick electrodes to maintain good conductivity by modifying the compositional parameters rather than reducing thickness, thus resolving the contradiction between capacity and conductivity.
Solution Approach 2:
The invention uses composite materials by combining active materials with conductive additives (such as carbon black, acetylene black, or metal powders) and specific binders. This composite structure ensures that even in thick electrodes, conductive pathways are maintained throughout the electrode bulk, preventing the conductivity deterioration that normally occurs with increased thickness.
2Quantity of substance
If the positive electrode is made thick to increase capacity, then the energy storage increases, but surface cracks develop reducing performance
Solution Approach 1:
The invention introduces conductive materials and optimized binders as intermediary substances within the electrode structure. These intermediaries fill and bridge potential crack formations, maintaining structural integrity and electrical continuity in thick electrodes, thus preventing the harmful effects of surface cracks while preserving high energy storage capacity.
Solution Approach 2:
By changing the compositional parameters - specifically increasing conductive material content to 5-20 wt% and optimizing binder content to 5-20 wt% - the invention modifies the mechanical and electrical properties of thick electrodes. This parameter optimization prevents crack formation and maintains performance in high-capacity thick electrode designs.
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 solution results in a rechargeable lithium battery with improved electrical conductivity, increased capacity, and stable cycle-life characteristics, as demonstrated by enhanced charge and discharge characteristics and increased discharge capacity compared to conventional methods.
Implementation Method 1
hot-pressing the positive active material layer and the current collector
Implementation Method 2
a positive electrode including a positive active material that can intercalate and deintercalate lithium
Data Source
AI summary
A positive electrode for a rechargeable lithium battery including a net-type current collector and a positive active material layer formed on both sides of the current collector and also including a positive active material and a binder and having a thickness of about 150 μm or more, a method of manufacturing the same, and a rechargeable lithium battery including the same.