Liquid-Retaining Separator Structure for Battery Cycling Stability
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Solution Overview
Problem
Battery cells exhibit poor cycling performance due to electrolyte solution extrusion during charge-discharge cycles, leading to liquid shortage, battery polarization, and reduced cycle life.
Innovation Solution
A separator comprising a liquid-retaining polymer with specific mass retention properties under ambient and pressurized conditions, designed to minimize electrolyte extrusion and enhance liquid retention, thereby improving cycling performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional separators are used in battery cells, then the battery can operate, but electrolyte solution is extruded during charge-discharge cycles leading to poor cycling performance
Solution Approach 1:
The separator employs a porous polymer structure with controlled porosity (30-80%) that allows electrolyte retention through capillary forces while maintaining ion transport. The porous structure enables the separator to absorb and hold electrolyte solution within its matrix, preventing extrusion during battery cycling operations.
Solution Approach 2:
The invention modifies the physical and chemical parameters of the separator by incorporating polymers with specific glass transition temperatures (-100°C to 100°C) and melting temperatures (80°C to 200°C). These parameter changes enable the separator to maintain optimal electrolyte retention and mechanical stability across different operating conditions and charge-discharge cycles.
2Quantity of substance
If the separator retains more electrolyte solution, then liquid shortage is reduced, but the separator structure becomes more complex
Solution Approach 1:
The separator utilizes composite polymer structures combining different polymer materials with complementary properties. This composite approach achieves enhanced electrolyte retention capacity while maintaining structural simplicity through the synergistic effects of the polymer components, avoiding the need for complex multi-layer or multi-component designs.
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 separator effectively reduces electrolyte extrusion, mitigates battery polarization, and enhances cycling performance by maintaining electrolyte retention, thus extending the battery's cycle life.
Implementation Method 1
the separator has a strong liquid-retaining capacity
Implementation Method 2
the separator comprises the liquid-retaining polymer
Data Source
AI summary
A separator, a battery cell, a battery, and an electric device. The separator comprises a liquid retention polymer, and the separator satisfies the following formula: (m2−M)/(m1−M)≥25%, wherein M represents the mass of the electrolyte not absorbed by the separator, and the unit thereof is g; m1 represents the mass of the separator weighed under an ambient pressure after having been immersed in the electrolyte for 2 h, and the unit thereof is g; and m2 represents the mass of the separator weighed under a pressure of 10,000 N in the ambient pressure after having been immersed in the electrolyte for 2 h, and the unit thereof is g.