Battery Separator Coating Using Metal Alkanoate Binder
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Solution Overview
Problem
Conventional secondary battery separators using organic binders face issues such as chemical reactions with electrolyte solutions, pore closure, and decreased charge/discharge capacity due to organic binder swelling, leading to reduced battery performance and safety concerns.
Innovation Solution
A separator for secondary batteries is developed using a metal alkanoate with a polar group to bind inorganic particles and the porous substrate, eliminating the need for organic binders, thereby enhancing adhesive strength, thermal resistance, and maintaining pore integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If an organic binder is used to bind inorganic particles and porous sheet, then adhesion is improved, but chemical reactions with electrolyte solution, pore closure, and swelling occur leading to degraded battery performance
Solution Approach 1:
The patent removes the organic binder component from the ceramic layer composition entirely. The ceramic layer is formed using only inorganic particles without any organic binding agent, thereby eliminating the source of chemical reactions, swelling, and pore closure that degrade battery performance while maintaining adhesion through alternative inorganic-based bonding mechanisms.
Solution Approach 2:
The patent changes the chemical composition parameters of the ceramic layer by excluding organic binders and using specific inorganic particle compositions and ratios. This parameter change transforms the layer from an organic-containing composite to a purely inorganic structure that is chemically stable in the electrolyte environment while maintaining mechanical integrity.
2Temperature
If a ceramic layer with inorganic particles is introduced on porous sheet, then thermal resistance is improved, but organic binder components cause pore closure and chemical reactions
Solution Approach 1:
The patent extracts and removes all organic binder components from the ceramic layer formulation. The ceramic layer consists exclusively of inorganic particles that are chemically inert to the electrolyte solution, thereby maintaining thermal resistance properties while eliminating harmful chemical reactions, gas generation, and pore closure effects.
Solution Approach 2:
The patent creates a chemically inert environment within the ceramic layer by using only inorganic particles that do not react with the electrolyte solution. This inert composition prevents chemical reactions, gas evolution, and degradation while maintaining the thermal stability function of the ceramic layer.
3Strength
If organic binder is used for binding inorganic particles, then adhesion is achieved, but elution and swelling occur reducing battery capacity
Solution Approach 1:
The patent removes organic binders from the ceramic layer composition, eliminating the source of elution and swelling that reduce battery capacity. Adhesion is maintained through inorganic particle-to-substrate bonding mechanisms that do not involve organic polymers, thereby preserving battery capacity and preventing performance degradation over time.
4Ease of manufacture
If separator uses conventional organic binder, then manufacturing is simplified, but pore closure and chemical instability occur
Solution Approach 1:
The patent removes organic binders from the ceramic layer, simplifying the material composition to purely inorganic components. This extraction eliminates chemical instability and pore closure issues while the manufacturing process remains straightforward through slurry preparation and coating methods that form the ceramic layer without requiring organic binder addition or removal steps.
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 new separator design achieves low thermal shrinkage, high permeability, and improved electrical properties by ensuring smooth lithium ion movement, increased thermal and chemical resistance, and enhanced safety against rapid temperature rises.
Implementation Method 1
a metal alkanoate having a polar group binds among the particles and also between the particles and the porous substrate
Implementation Method 2
lithium ion movement is smooth to significantly improve electrical properties
Data Source
AI summary
Provided are a separator for a secondary battery, a method for manufacturing the same, and a lithium secondary battery including the same, and particularly, a separator for a secondary battery which has sufficient thermal resistance and mechanical properties even without using a polymer-based organic binder lacking chemical stability, by adopting a metal alkanoate having a polar group as a binder for binding among particles forming a porous active layer and also between the porous active layer and a porous substrate. A method for manufacturing the same, and a lithium secondary battery including the same are also provided.