Nanocellulose-Coated Battery Separator for Heat and Moisture Balance
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Solution Overview
Problem
Existing secondary battery separators struggle to balance high energy density with high thermal safety performance and long service life, often compromising on one aspect at the expense of others.
Innovation Solution
A separator comprising a porous substrate with a coating layer made of nanocellulose and a filler, where the moisture content and coating layer thickness are controlled within specific ratios (250≤A/H≤1500) to achieve excellent heat resistance, low moisture content, and good electrolyte infiltration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a coating layer is added to improve thermal safety performance, then heat resistance is improved, but moisture content increases and energy density decreases
Solution Approach 1:
The coating layer is designed with a porous structure having specific porosity (30-70%) to maintain electrolyte infiltration while providing thermal safety. The porous structure allows the coating to be thermally protective without completely blocking ion transport, thus balancing heat resistance with energy density preservation
Solution Approach 2:
The patent optimizes multiple parameters including coating thickness (5-20 μm), porosity (30-70%), and moisture content (250≤A/H≤1500) to achieve the desired balance. By carefully controlling these parameters, the coating provides thermal protection while minimizing the impact on energy density and maintaining good electrolyte infiltration
2Temperature
If coating layer thickness is increased to improve heat resistance, then thermal safety performance is improved, but moisture content increases and electrolyte infiltration deteriorates
Solution Approach 1:
The coating layer employs a porous structure with optimized porosity (30-70%) that allows electrolyte to penetrate through the coating while the coating itself provides thermal protection. This porous architecture enables the coating to be thermally protective without compromising ion transport
Solution Approach 2:
The patent specifies an optimal coating thickness range of 5-20 μm and porosity range of 30-70% to balance thermal protection with electrolyte infiltration. These parameter optimizations ensure the coating is thick enough for heat resistance but thin and porous enough to allow electrolyte penetration
3Temperature
If nanocellulose content is increased to improve heat resistance, then thermal safety performance is improved, but moisture content increases
Solution Approach 1:
The patent controls the moisture content parameter by optimizing the ratio A/H (where A is moisture content and H is coating thickness) to be within 250-1500. This parameter control ensures that even with nanocellulose content increased for heat resistance, the moisture content remains within acceptable limits
Solution Approach 2:
The coating layer is formulated as a composite material containing nanocellulose, binder, and optional inorganic fillers. This composite structure allows the nanocellulose to provide heat resistance while the overall formulation controls moisture content through optimized composition and processing
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 proposed separator enhances the secondary battery's energy density, thermal safety performance, and extends its service life by maintaining optimal moisture levels and electrolyte infiltration.
Implementation Method 1
the separator has a moisture content of A ppm, the coating layer has a thickness of H μm, and the separator satisfies 250≤A/H≤1500
Data Source
AI summary
Provided in the present application are a separator, a method for preparing the same, and a secondary battery and an electrical device related thereto. The separator comprises a porous substrate and a coating layer disposed on one or more surface of the porous substrate, wherein the coating layer comprises nanocellulose and a filler, and the separator has a moisture content of A ppm, the coating layer has a thickness of H μm, and the separator satisfies 250≤A/H≤1500. The separator of the present application has the characteristics including excellent heat resistance, low moisture content and good electrolyte infiltration, so that a secondary battery using the separator can have the combined characteristics of high energy density, high thermal safety performance, and long service life.