Sulfonic Polysulfone Separator for Lithium Battery
Solution Overview
Problem
Lithium rechargeable batteries face issues with metal ion deposition between electrodes, leading to performance deterioration and safety concerns, particularly with nickel ions from positive electrodes, and require improved heat resistance to prevent separator shrinkage and mechanical damage.
Innovation Solution
A separator for lithium rechargeable batteries is developed, featuring a porous substrate with a heat-resistant porous layer containing sulfonic acid group-containing polysulfone, which effectively traps metal ions and enhances thermal stability by applying a nano dispersion liquid of sulfonic acid group-containing polysulfone on the substrate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a separator is used in lithium rechargeable batteries, then ion conductivity is maintained and electrodes are separated, but the separator mechanically shrinks or is damaged due to melting characteristics at high temperature
Solution Approach 1:
The patent applies composite materials by combining organic binder polymers (polyacrylic acid, polyacrylamide, carboxymethyl cellulose, or starch) with inorganic particles (alumina, silica, boehmite, or titania) to form a heat-resistant porous layer. This composite structure provides both the flexibility and ion conductivity of organic materials and the high-temperature stability of inorganic materials, preventing separator shrinkage and damage at elevated temperatures while maintaining operational reliability.
2Temperature
If inorganic particles are mixed with organic binder and coated on separator to increase thermal resistance, then heat resistance is improved, but the complexity of manufacturing increases
Solution Approach 1:
The patent controls the particle size of inorganic particles within a specific range of 0.1 to 2.0 micrometers and maintains the content of inorganic particles at 1 to 50 parts by weight per 100 parts by weight of organic binder. These parameter optimizations ensure effective heat resistance improvement while maintaining manufacturing feasibility and avoiding excessive complexity in the coating process.
3Reliability
If metal ions are not trapped, then ion conductivity is maintained, but metal ions deposit on negative electrode causing performance deterioration and safety concerns
Solution Approach 1:
The heat-resistant porous layer acts as an intermediary between the positive and negative electrodes, containing inorganic particles with high surface area and specific surface charge that adsorb and trap metal ions (such as nickel ions) eluted from the positive electrode. This prevents metal ion deposition on the negative electrode while maintaining ion conductivity through the porous structure, thereby improving battery safety and performance.
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 effectively prevents nickel ion deposition on negative electrodes, improves cycle-life characteristics, and enhances heat resistance, thereby improving the safety and performance of lithium rechargeable batteries.
Implementation Method 1
the heat resistance porous layer includes a sulfonic acid group-containing polysulfone... may trap metal ions eluted from a positive electrode effectively
Data Source
AI summary
The present invention relates to a separator for a lithium secondary battery, a method for manufacturing the separator, and a lithium secondary battery including the separator. The separator includes a porous substrate and a heat resistance porous layer positioned on at least one surface of the porous substrate, wherein the heat resistance porous layer includes a sulfonic acid group-containing polysulfone.