Carbon-Coated Current Collector for Low-Resistance Battery Interfaces
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing current collectors for electrical storage devices face issues with poor dispersibility of carbon fine particles in PVDF-based slurries, leading to uneven coating and low adhesion, which results in increased resistance and reduced performance.
Innovation Solution
A coating liquid containing acid-modified polyvinylidene fluoride and polyvinylpyrrolidone is used to disperse powdery carbon materials, enhancing adhesion and conductivity on the substrate, thereby forming a uniform and low-resistance coating layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If PVDF-based slurry is used to coat carbon fine particles on current collector, then the coating provides electrical conductivity and reduces resistance, but the carbon fine particles exhibit poor dispersibility leading to uneven coating and low adhesion
Solution Approach 1:
The patent introduces a dispersant as an intermediary substance between PVDF and carbon fine particles. The dispersant has both hydrophobic groups that interact with carbon particles and hydrophilic groups that interact with PVDF, acting as a bridge to achieve uniform dispersion of carbon particles in the slurry, thereby enabling even coating while maintaining electrical conductivity
Solution Approach 2:
The patent creates a composite slurry system combining PVDF, carbon fine particles, and dispersant. This composite material approach allows the dispersant to modify the interface between PVDF and carbon particles, improving overall dispersibility and coating uniformity while preserving the electrical conductivity function of the carbon network
2Use of energy by moving object
If high voltage is applied to increase battery capacity, then the energy storage increases, but the binder resins are oxidatively decomposed causing functional deterioration
Solution Approach 1:
The patent changes the chemical composition parameter of the binder resin from conventional polymers to PVDF, which has inherently higher oxidation resistance. This parameter change allows the binder to withstand high voltage conditions (4.2V or above) without oxidative decomposition, enabling high energy storage capacity while maintaining reliability
3Reliability
If carbon coating layer is applied to reduce interface resistance, then the electrical performance improves, but the adhesion between coating and substrate decreases due to poor dispersibility
Solution Approach 1:
The dispersant acts as a mediator that enhances the interaction between carbon particles and PVDF binder. By improving the interfacial adhesion at the micro level through molecular-level interactions, the dispersant ensures strong bonding between the carbon coating layer and substrate while maintaining electrical performance
Solution Approach 2:
The patent optimizes the dispersant concentration in the slurry to achieve the best balance between dispersibility and adhesion. By controlling the amount of dispersant, the system achieves optimal carbon particle distribution and coating formation, ensuring both electrical performance and adhesion strength
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 enables uniform application and improved adhesion of the coating layer, reducing the interface resistance and enhancing the performance of electrical storage devices.
Implementation Method 1
the content of the polyvinylpyrrolidone in the coating layer is 0.099 to 5.0 mass%, wherein the dispersibility of the powdery carbon material is enhanced
Implementation Method 2
a coating layer disposed on one or both sides of the conductive substrate
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
[Object] To provide a current collector for electrical storage device which allows an electrical storage device to attain a low resistance. [Solution] A current collector for electrical storage device includes a sheet-shaped conductive substrate and a coating layer disposed on one or both sides of the conductive substrate. The coating layer includes a powdery carbon material, acid-modified polyvinylidene fluoride and polyvinylpyrrolidone. The content of the polyvinylpyrrolidone is 0.099 to 5.0 mass%. The content of the powdery carbon material in the coating layer is 15.0 to 45.0 mass%.