UV-Crosslinked Separator Coating for High-Temperature Battery Safety
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Solution Overview
Problem
Existing battery separator production methods face challenges such as high processing difficulty, high production costs, and low crosslinking consistency, leading to premature melting and rupture during overcharging or external stress, which can cause battery fires or explosions.
Innovation Solution
A coating slurry comprising an organic polymer, a solvent, and a photoinitiator is applied to a substrate, followed by UV crosslinking to form a 3D network structure, enhancing the breakage temperature and safety of the separator.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a crosslinking agent is directly mixed with raw materials and extruded at high temperature, then crosslinking occurs, but processing difficulty increases and production cost rises
Solution Approach 1:
The patent replaces thermal crosslinking (mechanical/thermal system) with photo-crosslinking using a photoinitiator and UV light. The coating slurry contains a photoinitiator that activates crosslinking reactions upon UV irradiation, eliminating the need for high-temperature extrusion and complex processing while achieving complete and uniform crosslinking.
2Reliability
If a crosslinking agent is directly mixed with raw materials, then crosslinking occurs, but the crosslinking agent cannot be fully dispersed and reacted completely
Solution Approach 1:
The patent uses a photoinitiator as an intermediary substance that enables uniform crosslinking throughout the coating layer. The photoinitiator disperses evenly in the coating slurry and activates crosslinking reactions uniformly upon UV irradiation, ensuring complete reaction and consistent product quality without aggregation or incomplete reaction zones.
3Productivity
If polyolefin polymers are used as membrane materials, then mass production is universal and economical, but the separator melts and ruptures at high temperature causing safety issues
Solution Approach 1:
The patent creates a composite coating structure by applying a coating slurry containing organic polymer and photoinitiator onto the polyolefin separator. After UV irradiation, a crosslinked coating layer forms on the separator surface, combining the mass-producible polyolefin base with a high-temperature-resistant crosslinked coating, thereby maintaining productivity while dramatically improving thermal stability and 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 UV crosslinking process improves the breakage temperature of the separator by 20° C. to 80° C., increasing thermomechanical strength and safety while maintaining low production costs and simplifying the manufacturing process.
Implementation Method 1
a crosslinking structure formed by photo-crosslinking of a photoinitiator
Data Source
AI summary
A coating slurry for a battery separator includes an organic polymer, a solvent, and a photoinitiator. A coated separator prepared with the coating slurry, and a preparation method of the coated separator are also provided. The preparation method of the coated separator includes: coating the coating slurry on at least one surface of a substrate, and irradiating a coated substrate under ultraviolet (UV) light with a set energy and wavelength to allow UV crosslinking to obtain the coated separator.