Secondary Battery Electrode Composite Conductive Coating
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional lithium secondary batteries face issues with deteriorated charge and discharge capacities and lifespan due to separation of electrode active material components from the current collector, leading to reduced adhesion and poor electrical conductivity.
Innovation Solution
A cathode for secondary batteries is developed with a second conductive material coated to a thickness of 30 to 60 µm on the current collector, covering 50 to 80% of its area, using materials like graphite, carbon nanotubes, or graphene, and incorporating a spinel-structure lithium metal oxide as the cathode active material, along with a binder and first conductive material, to enhance adhesion and electrical conductivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional thin conductive coating is applied to the current collector, then the adhesion between electrode active material and current collector is improved, but the electrical conductivity is insufficient
Solution Approach 1:
The patent applies a composite coating structure consisting of a first conductive material layer (30-60 μm thickness) and a second conductive material layer (5-20 μm thickness) on the current collector. The first conductive material provides strong adhesion and bulk conductivity, while the second conductive material enhances surface conductivity and electron transport to the electrode active material, resolving the contradiction between adhesion and electrical conductivity.
2Object-generated harmful factors
If the conductive material coating thickness is increased, then the electrical conductivity is improved, but the adhesion between electrode active material and current collector deteriorates
Solution Approach 1:
The conductive coating is segmented into two distinct layers with different functions: the first conductive material layer (thicker, 30-60 μm) provides mechanical adhesion and bulk electrical conductivity, while the second conductive material layer (thinner, 5-20 μm) provides enhanced surface conductivity. This segmentation allows each layer to optimize its thickness for its specific function, resolving the contradiction between conductivity and adhesion.
Solution Approach 2:
Different regions of the coating structure have different properties: the first conductive material layer has higher thickness and provides mechanical support and adhesion, while the second conductive material layer has lower thickness and provides superior electrical conductivity at the interface with the electrode active material. This local quality differentiation resolves the contradiction by assigning different optimization priorities to different layers.
3Object-generated harmful factors
If a uniform conductive coating is applied over the entire current collector, then the electrical conductivity is improved, but the manufacturing complexity increases
Solution Approach 1:
The second conductive material layer is applied selectively to specific regions where enhanced conductivity is most needed, such as areas with high current density or poor natural conductivity, rather than uniformly across the entire current collector. This partial application reduces manufacturing complexity while still achieving the desired electrical conductivity improvement in critical areas.
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 configuration improves electrical conductivity, reduces internal resistance, and enhances rate characteristics, thereby extending the battery's cycle life and performance.
Implementation Method 1
a second conductive material is coated to a thickness of 30 to 60 μm on the current collector and the electrode mixture is coated on a coating layer of the second conductive material so as to improve electrical conductivity
Data Source
Figure 1
Figure 2
AI summary
Disclosed is an electrode for secondary batteries including an electrode mixture including an electrode active material, binder and conductive material coated on a current collector wherein a conductive material is coated to a thickness of 1 to 80 µm on the current collector and the electrode mixture is coated on a coating layer of the conductive material so as to improve electrical conductivity.