Asymmetrical Separator for Lithium-Ion Battery Safety
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Solution Overview
Problem
Lithium-ion batteries face challenges in large-scale energy storage due to thermal stress, safety concerns, and reduced lifespan caused by poor heat dissipation, which necessitates improved separators that can handle high-voltage cathode and reducing anode materials effectively.
Innovation Solution
A separator with asymmetrical structure and different material consistencies on the anode and cathode sides, featuring a fine-pored barrier layer and specific fillers like Al2O3 and polyvinylidene fluoride, which enhances chemical stability, prevents dendrite growth, and maintains safety and high energy/power density.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a uniform separator material is used on both anode and cathode sides, then the separator structure is simple and easy to manufacture, but it cannot adequately address the different chemical and electrochemical stability requirements of the two electrode sides
Solution Approach 1:
The separator is designed with different material compositions on the anode side and cathode side. The anode side contains materials with high reduction stability while the cathode side contains materials with high oxidation stability, allowing each side to be optimized for its specific electrochemical environment without requiring a completely complex asymmetric structure
Solution Approach 2:
The separator employs an asymmetrical structure where the anode side and cathode side have different material consistencies. This asymmetry enables the separator to be matched to the different requirements for chemical or electrochemical stability on the respective electrode sides, ensuring safe operation while maintaining a relatively simple overall structure
2Quantity of substance
If high-voltage cathode materials are used to increase battery capacity, then energy density increases, but the separator faces new demands for chemical stability against strongly oxidizing materials
Solution Approach 1:
The cathode side of the separator is specifically designed with materials that have high oxidation stability to withstand the strongly oxidizing high-voltage cathode materials. This localized material selection allows the battery to use high-voltage cathodes for increased capacity while the separator provides targeted chemical stability protection at the cathode interface
3Productivity
If the separator porosity is increased to improve ion transport, then charging speed increases, but dendrite growth may be promoted reducing safety
Solution Approach 1:
The separator employs different porosity levels on the anode and cathode sides. The anode side has optimized porosity to prevent dendrite growth while maintaining adequate ion transport, and the cathode side has porosity optimized for ion transport to enable rapid charging. This localized porosity optimization allows the battery to charge quickly while maintaining safety
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 addresses thermal stress and safety concerns, enabling rapid charging with reduced dendrite growth and maintaining high energy/power density, thus enhancing the operational reliability and lifespan of lithium-ion batteries.
Implementation Method 1
particles of polyvinylidene fluoride withstand the oxidizing cathode materials
Implementation Method 2
particles of Al 2 O 3 withstand the reducing anode materials
Implementation Method 3
A fine-pored barrier layer is formed on the anode side. This can prevent dendrite growth
Data Source
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AI summary
The invention relates to a separator for arranging in a battery, comprising a basic body (1), wherein the basic body (1) has an anode side (2) for contacting the anode of a battery, and a cathode side (3) for contacting the cathode of a battery. In view of the objective to provide a separator which can be inserted in a lithium ion battery without difficulty, and which increases the operational safety of the lithium ion battery, the separator is characterized in that the material consistency of the anode side (2) is different from the material consistency of the cathode side (3).