Porous Insulating Layer Composition for Lithium Battery Electrodes
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Solution Overview
Problem
Conventional methods for preparing porous insulating layers for non-aqueous electrolyte rechargeable batteries face challenges in suppressing the thickness increase of active material layers and ensuring stable dispersion of polyolefin-based polymer particles, leading to irregular coating and potential safety issues due to moisture absorption and agglomeration.
Innovation Solution
A composition comprising a polyolefin-based polymer particle, an insulating inorganic particle, and a binder with specific monomer units, along with a solvent system that includes water and an organic solvent, is used to form a porous insulating layer on an active material layer, ensuring uniform dispersion and preventing excessive thickness increase.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If material slurry containing water is coated on the active material layer, then the porous insulating layer can be formed, but the active material layer swells due to moisture permeation, increasing its thickness
Solution Approach 1:
The patent changes the solvent composition parameters by using organic solvents with specific boiling points (≥160°C) instead of water, and controls the water content at ≤5 wt% to prevent moisture-induced swelling while maintaining coating processability
Solution Approach 2:
The patent introduces a specifically designed binder polymer as an intermediary substance that is insoluble in the organic solvent system, creating a barrier that prevents moisture permeation into the active material layer while still allowing the coating to be applied
2Manufacturing precision
If the ratio of water is reduced and organic solvent ratio is increased in the material slurry, then the thickness increase of active material layer is suppressed, but the polyolefin-based polymer particle stability deteriorates and agglomeration occurs
Solution Approach 1:
The binder polymer acts as a protective intermediary between the polyolefin-based polymer particles and the organic solvent environment, preventing direct interaction that would cause agglomeration while maintaining particle dispersion stability
Solution Approach 2:
The patent creates a composite coating system combining the polyolefin-based polymer particles with the binder polymer and insulating inorganic particles, where the binder provides stability to the polyolefin particles in the organic solvent medium
3Reliability
If polyolefin-based polymer is included in the porous insulating layer for shut-down function, then safety is improved, but the active material layer thickness is excessively increased due to moisture absorption
Solution Approach 1:
The patent changes the solvent system parameters to use organic solvents with high boiling points (≥160°C) and limits water content to ≤5 wt%, eliminating moisture-induced swelling while preserving the shut-down safety function of polyolefin-based polymer
Solution Approach 2:
The binder polymer serves as a moisture barrier intermediary that allows the polyolefin-based polymer to provide safety functions without exposing the active material layer to moisture that would cause excessive thickness increase
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 suppresses the thickness increase of active material layers, enhances the dispersion stability of polyolefin-based polymer particles, and improves the coating properties, resulting in a safer and more reliable non-aqueous electrolyte rechargeable battery with a uniform porous insulating layer.
Implementation Method 1
a shut-down function of increasing internal resistance of the battery by closing pores of a separator through melting during abnormal overheating
Implementation Method 2
the binder includes a polymer, the polymer includes at least one monomer unit (A) and at least one monomer unit (B)... capable of suppressing a layer thickness increase of an active material layer when being coated thereon
Implementation Method 3
enhances the dispersion stability of polyolefin-based polymer particles... a solvent including water and an organic solvent
Data Source
Figure 1
AI summary
A composition for preparing a porous insulating layer for a non-aqueous electrolyte rechargeable battery, an electrode prepared using the same, a non-aqueous electrolyte rechargeable battery, and a method of preparing an electrode, wherein the composition for preparing the porous insulating layer is a composition for preparing a porous insulating layer for a non-aqueous electrolyte rechargeable battery on an active material layer disposed on a current collector and comprising an active material capable of electrochemically intercalating and deintercalating lithium ions, the composition for preparing the porous insulating layer includes a polyolefin-based polymer particle, a binder, an insulating inorganic particle, and a solvent including water and an organic solvent, the binder includes a polymer, the polymer includes at least one monomer unit (A) represented by Chemical Formula 1 and at least one monomer unit (B) represented by Chemical Formula 2, and in the polymer, a weight ratio (A)/(B) of the monomer unit (A) and the monomer unit (B) ranges from 40/60 to 80/20.