Battery Separator Polymer Layer for Ion Diffusion and Dissolution Resistance
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Solution Overview
Problem
Existing battery cells exhibit poor storage performance due to issues with electrolyte solution diffusion and polymer dissolution, leading to reduced ion conductivity and concentration polarization.
Innovation Solution
A separator with a polymer layer made of aldehyde ketone polymer, which forms a three-dimensional connected interface with electrode plates, enhancing ion diffusion and reducing polymer dissolution through controlled molecular chain entanglement and flexibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the polymer molecular chains are highly entangled to lock electrolyte solution, then polymer dissolution resistance improves, but ion diffusion between molecular chains deteriorates
Solution Approach 1:
The patent applies parameter changes by controlling the elastic modulus ratio (G'/G'') to be between 0.8 and 100 at specific temperature and frequency conditions. This parameter optimization achieves the right balance between molecular chain entanglement (for locking electrolyte) and chain spacing (for ion diffusion), resolving the contradiction between polymer stability and ion conductivity.
2Stability of the object's composition
If the polymer forms a dense structure to reduce dissolution, then polymer stability improves, but ion conductivity deteriorates
Solution Approach 1:
The patent uses parameter changes by optimizing the elastic modulus ratio (G'/G'') to achieve a specific structural state where the polymer maintains stability while allowing ion transport. The controlled ratio ensures the polymer neither forms a too-dense structure nor a too-loose structure, balancing stability and conductivity.
Solution Approach 2:
The patent creates a composite interface structure where the polymer layer with controlled molecular entanglement forms a three-dimensional connected interface with electrode plates. This composite structure combines the stability of entangled polymer chains with the conductivity of interconnected pathways for ion transport.
3Productivity
If the polymer molecular chains are stretched to promote electrolyte diffusion, then ion conductivity improves, but polymer structural integrity deteriorates
Solution Approach 1:
The patent applies parameter changes by controlling the elastic modulus ratio (G'/G'') to optimize the molecular chain conformation. This parameter control allows molecular chains to achieve an optimal state that provides both sufficient openness for electrolyte diffusion and adequate entanglement for structural integrity, avoiding complete chain stretching that would compromise strength.
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
Improves storage performance by increasing ion conductivity and reducing concentration polarization, allowing for rapid and uniform ion deposition, thereby enhancing battery cell stability and efficiency.
Implementation Method 1
the polymer and the electrolyte solution can form a three-dimensional connected interface between the separator and an electrode plate, and the interface has a mesh structure, which is conducive to increasing the rate of diffusion of active ions, such as lithium ions, from the electrolyte solution phase to the electrode plate
Implementation Method 2
the polymer still maintains a certain molecular chain entanglement state, which is capable of locking the electrolyte solution inside the polymer, and is capable of reducing the risk of the polymer dissolving in the electrolyte solution
Data Source
AI summary
The present application provides a separator, a battery cell, a battery and an electrical apparatus. The separator comprises a separator body and a polymer layer arranged on at least one surface of the separator body. The polymer layer comprises an aldehyde ketone polymer. The aldehyde ketone polymer is made into a sheet-like structural body; the sheet-like structural body is subjected to a dynamic frequency scanning test at (Tm+20)° C. to obtain an elastic modulus G′−loss modulus G″ curve, and the elastic modulus G′−loss modulus G″ curve has a slope of K, wherein 0.8≤K<∞, and Tm° C. represents a melting temperature of the aldehyde ketone polymer.