Porous Battery Separator with Embedded Polymer for Thermal Shrinkage
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Solution Overview
Problem
Current separators for lithium secondary batteries face challenges in achieving high heat resistance, strength, and reduced thermal shrinkage while maintaining a thin structure, as existing solutions either complicate manufacturing or compromise on energy density or safety.
Innovation Solution
A separator with a porous structure embedded with a highly heat-resistant particle-type polymer, where the polymer is integrated into the pores, maintaining the same thickness as the original separator and enhancing heat resistance and strength without adding a coating layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a coating layer including an inorganic material is added to the outer surface of a separator substrate to improve heat resistance, then thermal properties are improved, but the overall thickness of the separator increases
Solution Approach 1:
The heat-resistant polymer particles are embedded within the pores of the separator substrate, creating a nested structure where the functional material is contained inside the porous matrix. This allows the separator to gain thermal resistance properties without adding external coating layers that would increase thickness.
Solution Approach 2:
The invention utilizes the porous structure of the separator substrate to embed heat-resistant polymer particles within the pores. This approach leverages the existing porous architecture to incorporate functional materials internally, avoiding the need for additional coating layers and maintaining thin overall thickness while improving heat resistance.
2Quantity of substance
If the separator thickness is reduced to achieve high energy density, then energy density is improved, but the strength and thermal shrinkage resistance of the separator deteriorate
Solution Approach 1:
The separator is constructed as a composite material system combining the porous substrate with embedded heat-resistant polymer particles. This composite structure provides both mechanical strength from the substrate and thermal stability from the polymer particles, enabling thin separator design that maintains adequate strength and shrinkage resistance for high energy density applications.
Solution Approach 2:
The heat-resistant polymer particles are distributed within the pores of the separator substrate, providing localized thermal and mechanical reinforcement where needed. This localized enhancement allows the overall separator to maintain thin thickness while having strengthened regions that prevent thermal shrinkage and maintain structural integrity.
3Force
If baroplastic polymer powder is inserted into pores and pressed to prevent separation, then binding force is improved, but the separator strength is reduced due to polymer melting at high temperature
Solution Approach 1:
The invention uses heat-resistant polymer particles that do not melt at battery operating temperatures, replacing the baroplastic polymer approach. These particles remain stable and maintain separator strength even at high temperatures, avoiding the strength loss that occurs when baroplastic polymer melts during normal battery operation or abuse conditions.
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 allows for a thin, high-strength separator with improved thermal shrinkage resistance and permeability, addressing the limitations of existing technologies by embedding a heat-resistant polymer within the separator's pores, thus enhancing the battery's safety and energy density.
Implementation Method 1
a particle type polymer embedded in the separator body, wherein the particle type polymer includes a material having a heat resistance higher than a heat resistance of the separator body
Data Source
AI summary
A separator for a secondary battery, including a separator body having a porous structure and a particle type polymer embedded in the separator body. The particle type polymer includes a material having a heat resistance higher than a heat resistance of the separator body, whereby it is possible to provide a thin separator with improved thermal shrinkage.