Composite Porous Separator Coating for Wet and Dry Electrode Adhesion
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing secondary battery separators exhibit insufficient adhesion between electrodes and separators in both dry and wet states, leading to potential separation and local defects due to dislodged inorganic particles, compromising safety and durability.
Innovation Solution
A separator with an organic-inorganic composite porous coating layer containing a mixture of acrylic and PVDF-containing binders, which maintains high adhesion and stability under both dry and wet conditions, preventing inorganic particle dislodgment and enhancing thermal safety and insulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an inorganic porous coating layer is used to ensure chemical stability and porosity, then chemical stability is improved, but flexibility and adhesion to the collector deteriorate
Solution Approach 1:
The patent applies composite materials by combining organic porous polymer particles (providing flexibility and adhesion) with inorganic porous particles (providing chemical stability and porosity). This composite structure allows the coating layer to simultaneously achieve good adhesion to the collector, maintain flexibility, and provide the chemical stability required for electrochemical device operation.
2Productivity
If a porous coating layer is formed to facilitate electrolyte penetration and ion transport, then electrochemical performance is improved, but mechanical strength and structural integrity deteriorate
Solution Approach 1:
The patent employs porous materials by incorporating inorganic porous particles with controlled pore structures into the coating layer. These porous particles facilitate electrolyte penetration and ion transport while the composite structure with organic polymer particles maintains the mechanical strength and structural integrity of the separator.
3Quantity of substance
If the coating layer porosity is increased to enhance electrolyte absorption, then electrolyte retention is improved, but mechanical strength and structural stability deteriorate
Solution Approach 1:
The composite structure combines inorganic porous particles (enhancing electrolyte absorption and retention through their porous structure) with organic porous polymer particles (maintaining structural stability and mechanical strength). This allows the coating layer to hold adequate electrolyte while preserving structural integrity.
4Reliability
If inorganic particles are incorporated to provide chemical stability and porosity, then chemical stability is improved, but coating layer uniformity and manufacturing complexity deteriorate
Solution Approach 1:
The patent applies parameter changes by controlling the particle size distribution of both organic and inorganic particles within specific ranges (0.1-10 μm for organic particles, 0.5-20 μm for inorganic particles). This parameter control ensures uniform coating formation while maintaining the chemical stability and porosity benefits of the inorganic particles.
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 separator achieves improved adhesion and form stability, maintaining interfacial resistance and ion conduction, while preventing inorganic particle dislodgment, thus enhancing thermal safety and electrical insulation.
Implementation Method 1
a positive electrode separator comprising a positive electrode collector and a positive electrode porous coating layer formed on the positive electrode collector, the positive electrode porous coating layer comprising an organic porous coating layer and an inorganic porous coating layer
Data Source
Figure 1~2a
Figure 2b~3a
Figure 3b
AI summary
A separator according to the present invention comprises, on an organic/inorganic composite porous coating layer, a particulate binder resin comprising a mixture of an acryl-based binder and a PVDF-based binder, and thus has excellent adhesion with an electrode, in a dry state and in a wet state. Accordingly, in a roll-to-roll continuous process, the shape stability and processability of an electrode assembly can be improved, and even in a state of being impregnated with an electrolyte, a strong binding strength between the separator and an electrode can be maintained, and thus high adhesion can be maintained without degrading interfacial resistance characteristics. Thus, inorganic particles can be well fixed without detachment, thereby improving the shape stability of the separator. Accordingly, the heat stability and insulating properties of a battery can be improved, and due to a porous structure with an interstitial volume between particles in the porous coating layer, ion conduction between an electrode and the separator is not hindered, and thus the rate of resistance increase is low and lifespan characteristics are excellent.