Ceramic-Coated Battery Separator for High-Temperature Shrinkage Resistance
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Solution Overview
Problem
Existing battery separators fail to provide sufficient high-temperature heat stability, leading to safety issues due to large-area shrinkage under thermal stress.
Innovation Solution
A battery separator with a high-heat-resistant ceramic coating is developed, comprising a base membrane coated with ceramic powder and a binder, where the ceramic powder includes inorganic substances with a density of 5-15 g/cm3, forming a rigid framework to prevent shrinkage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If aluminium oxide or boehmite is coated on a polyolefin microporous film to improve heat resistance, then the separator shows better thermal stability, but it cannot meet the high-temperature heat stability requirement at 220-300°C
Solution Approach 1:
The patent changes the density parameter of the ceramic coating material from conventional low-density materials (aluminium oxide, boehmite) to high-density inorganic substances (barium titanate, zirconium dioxide, yttrium oxide, cerium oxide) with densities of 5-15 g/cm³. This parameter change enables the separator to maintain dimensional stability at temperatures of 220-300°C, resolving the contradiction between heat resistance and high-temperature heat stability.
Solution Approach 2:
The patent creates a composite ceramic coating by combining high-density inorganic substances with binders to form a multi-component coating system. This composite material approach allows the coating to achieve both adhesion to the base membrane and high-temperature stability, enabling the separator to meet the stringent heat stability requirements at 220-300°C while maintaining structural integrity.
2Ease of manufacture
If the base membrane undergoes traction and stretching during preparation, then the membrane structure is formed, but internal stress causes large-area shrinkage under high-temperature environment
Solution Approach 1:
The patent applies preliminary anti-action by coating the high-density ceramic layer on the base membrane before the membrane experiences thermal stress. This ceramic coating acts as a pre-applied counterforce that prevents the internal stress-induced shrinkage from occurring, thereby maintaining dimensional stability while preserving the ease of membrane formation during preparation.
Solution Approach 2:
The patent utilizes the thermal expansion properties of high-density inorganic substances which exhibit different thermal expansion coefficients compared to the polyolefin base membrane. The ceramic coating with density 5-15 g/cm³ provides thermal stability that compensates for the base membrane's thermal contraction, preventing large-area shrinkage while maintaining the membrane's manufacturability.
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 ceramic coating enhances the separator's stability under high temperatures, reducing shrinkage and improving safety by acting as a 'pillar' in the three-dimensional structure, thereby enhancing thermal resistance.
Implementation Method 1
the base membrane has internal stress due to traction and stretching, and under a high-temperature environment, large-area shrinkage is caused by stress release due to the movement of molecular chains in the separator
Implementation Method 2
a ceramic material is distributed in the three-dimensional structure of the separator to form a specific rigid framework which can effectively prevent the separator from shrinking and melting under the thermal runaway condition
Data Source
AI summary
The present invention provides a battery separator with a high-heat-resistant ceramic coating, wherein the battery separator comprises a base membrane and a ceramic coating coated thereon, the ceramic coating includes ceramic powder and a binder, the binder is used for binding the ceramic powder on the base membrane, and the ceramic powder further includes at least one inorganic substance A with a density of 5-15 g/cm3. The present invention has the beneficial effect that when the base membrane is coated with the ceramic coating at least containing the inorganic substance A with the larger density, the inorganic substance A can play a role of “pillar” in the three-dimensional structure of the separator due to larger gravity so as to form a more stable rigid structure, thereby resisting large-area shrinkage caused by stress release due to the movement of molecular chains in the separator under a high-temperature environment.