Ceramic Coated Electrode Assembly for Secondary Battery Thermal Stability
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional secondary batteries face thermal instability issues due to defects in the ceramic coating layer, which can lead to internal shorts, thermal decomposition, and potential fires or explosions, as the polyolefin film separator melts or contracts at high temperatures.
Innovation Solution
A ceramic coating layer with specific particle size distribution and binder properties is applied to the electrodes, eliminating the need for a polyolefin film separator and ensuring uniform coating without defects, thereby enhancing thermal stability and preventing internal shorts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a polyolefin film separator is used to prevent electrical short between electrodes, then electrical insulation is improved, but thermal stability deteriorates because the separator melts or contracts at high temperatures
Solution Approach 1:
The invention changes the material parameter of the separator from polyolefin film to ceramic coating layer, fundamentally altering the thermal properties while maintaining electrical insulation functionality
Solution Approach 2:
The invention uses a composite ceramic coating layer composed of multiple ceramic particles (alumina, silica, zirconia, magnesia) with different properties to achieve both electrical insulation and high thermal stability simultaneously
2Temperature
If a ceramic coating layer is formed on the electrode to improve thermal stability, then thermal stability is improved, but manufacturing complexity increases due to the need for uniform coating without defects
Solution Approach 1:
The invention optimizes the viscosity parameter of the ceramic paste to a specific range (50-5000 cP) to achieve uniform coating without defects, simplifying the manufacturing process while ensuring thermal stability
Solution Approach 2:
The invention applies ceramic coating selectively on the electrode surface where thermal protection is most needed, ensuring uniform coverage without excessive material usage or complex multi-layer structures
3Ease of manufacture
If the ceramic coating layer contains uncoated parts, pin holes or cracks, then manufacturing is simplified, but reliability deteriorates because current concentrates at defective portions causing internal shorts
Solution Approach 1:
The binder acts as an intermediary material that fills gaps and connects ceramic particles, ensuring complete coverage and eliminating pin holes or cracks while maintaining the ease of paste application
Solution Approach 2:
The composite ceramic paste containing multiple ceramic particles and binder creates a defect-free coating layer that prevents current concentration, maintaining both manufacturing simplicity and high reliability
4Temperature
If the separator is damaged by prolonged high temperature, then thermal resistance is reduced, but harmful effects increase due to continuous melting and electrical short
Solution Approach 1:
The invention changes the chemical composition parameter from organic polyolefin to inorganic ceramic materials, raising the decomposition temperature well above battery operating temperatures and eliminating thermal decomposition risks
Solution Approach 2:
The invention converts the thermal weakness of polyolefin separators into a benefit by using ceramic materials that not only resist high temperatures but also actively prevent thermal runaway through their inherent thermal stability and flame resistance
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 provides improved thermal stability, preventing expansion of internal shorts and reducing the risk of thermal decomposition and explosions, while also improving charge/discharge rates and battery lifetime through uniform ceramic coating.
Implementation Method 1
a ceramic coating layer which is formed by coating a ceramic paste made by mixing a binder and a solvent with ceramic powder onto at least one of the cathode or anode
Data Source
Figure 1
Figure 2
Figure 3
AI summary
An electrode assembly of a secondary battery includes a cathode including a cathode active material layer, an anode including an anode active material layer, and a ceramic coating layer formed on at least one of surfaces of the cathode and anode that face each other. The ceramic coating layer includes a ceramic powder and a binder. The specific surface area of the ceramic powder is more than 1.5m2/g and less than 15.0m2/g, and, in the particle size distribution of the ceramic powder, the D10 value is more than 0.05 µm and the D90 value is less than 3.0 µm.