Dual Layer Electrode Binder Crystalline Phase Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional electrodes with a middle layer are prone to short-circuiting due to binder expansion at high temperatures, leading to degraded battery performance, necessitating a stable high-power electrode solution.
Innovation Solution
An electrode with a dual layer structure, featuring a middle layer and an electrode active material layer, where the binders have controlled weight average molecular weights and crystalline phases, preventing conductive agent short-circuiting by acting as a positive temperature coefficient material.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a middle layer with binder is added to the electrode structure, then the electrode performance is improved, but the binder expands at high temperatures causing short-circuiting of conductive agents
Solution Approach 1:
The patent changes the molecular weight parameter of the binder material. Specifically, it uses a binder with a weight average molecular weight of 60,000 to 300,000 in the middle layer and 300,000 to 1,000,000 in the electrode active material layer. This parameter change prevents the binder from expanding excessively at high temperatures while maintaining good dispersibility of conductive agents, thus preventing short-circuiting.
Solution Approach 2:
The patent creates a composite electrode structure with a dual-layer binder system. The middle layer contains a binder with specific molecular weight characteristics, while the electrode active material layer contains a binder with different molecular weight characteristics. This composite approach allows each layer to perform its specific function: the middle layer binder provides thermal stability, while the electrode active material layer binder ensures good dispersibility.
2Stability of the object's composition
If the binder molecular weight is increased to prevent expansion, then thermal stability is improved, but the dispersibility of conductive agents deteriorates
Solution Approach 1:
The patent applies local quality by assigning different binder molecular weights to different layers of the electrode. The middle layer uses a binder with moderate molecular weight (60,000-300,000) optimized for thermal stability and conductive agent dispersibility in that specific layer, while the electrode active material layer uses a binder with higher molecular weight (300,000-1,000,000) optimized for maintaining structural integrity. Each layer's binder properties are locally optimized for its specific function.
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 dual layer structure improves binder and conductive agent dispersibility, preventing short-circuiting at high temperatures, thereby enhancing the stability and performance of lithium secondary batteries.
Implementation Method 1
preventing conductive agent short-circuiting by acting as a positive temperature coefficient material
Data Source
AI summary
The present invention relates to an electrode having a dual layer structure, a method for manufacturing the same, and a lithium secondary battery comprising the same, the electrode comprising: an electrode current collector; a middle layer formed on at least one side of the electrode current collector; and an electrode active material layer formed on the middle layer, wherein the middle layer comprises a first binder, wherein the electrode active material layer comprises an electrode active material and a second binder, and wherein the first binder and the second binder are the same kind of material but have different crystalline phases.