Positive electrode plate and lithium-ion battery comprising the positive electrode plate
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Lithium-ion batteries face safety hazards due to internal short circuits, particularly between the positive electrode current collector and the negative electrode plate, which can occur during mechanical damage, leading to fires and failures.
Innovation Solution
A positive electrode plate design featuring a two-layer coating structure, where the first coating layer includes an inorganic filler, a first conductive agent, and a first binder, with a higher binder content than the second layer, ensuring strong bonding forces between the first coating layer and the positive electrode current collector, reducing the exposure of the collector surface and minimizing short circuit probability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single-layer positive electrode coating is used, then the structure is simple and manufacturing is easy, but the bonding force between the coating layer and current collector is insufficient, leading to higher risk of internal short circuit during mechanical damage
Solution Approach 1:
The positive electrode coating is divided into two distinct layers: a first coating layer with high binder content (≥30 wt%) that provides strong bonding to the current collector, and a second coating layer with lower binder content that contains the positive electrode active material. This segmentation allows each layer to perform its specific function optimally, with the first layer ensuring reliable adhesion and the second layer providing electrochemical functionality.
Solution Approach 2:
The patent employs a composite coating structure where the first coating layer acts as a binder-rich adhesive layer and the second coating layer serves as the functional active material layer. This composite approach combines materials with different properties to achieve both strong bonding and effective electrochemical performance, resolving the contradiction between reliability and simplicity.
2Strength
If the binder content in the coating layer is increased to improve bonding force, then the bonding strength increases, but the energy density and electrochemical activity may be reduced
Solution Approach 1:
By segmenting the coating into two layers with different binder contents, the patent concentrates the high binder content (≥30 wt%) only in the first coating layer where it is needed for bonding to the current collector. The second coating layer maintains lower binder content, preserving higher energy density and electrochemical activity in the active material layer.
Solution Approach 2:
The patent applies local quality by having different binder concentrations in different regions (layers) of the coating. The first coating layer has high binder content locally optimized for adhesion to the current collector, while the second coating layer has lower binder content locally optimized for energy density and electrochemical performance.
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 design enhances the safety performance of lithium-ion batteries by reducing the likelihood of internal short circuits during mechanical misuse, while maintaining comparable cycle performance to existing batteries.
Implementation Method 1
the positive electrode current collector is bonded with a part of the first binder, and a part of the positive electrode active material is bonded with another part of the first binder
Data Source
AI summary
Disclosed are a positive electrode plate and a lithium-ion battery including the same. The positive plate includes a positive electrode current collector and a positive electrode coating layer; and the positive electrode coating layer includes a first coating layer and a second coating layer, wherein the first coating layer is coated on the positive electrode current collector surface, and the second coating layer is coated on the first coating layer surface. The lithium-ion battery has a good safety performance, and when mechanical misuse (needling, weight impact) occurs, the probability of battery fire failure is significantly reduced.