Insulating Porous Layer for Battery Separator Discharge Output
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Solution Overview
Problem
Conventional nonaqueous electrolyte secondary batteries, particularly lithium secondary batteries, face issues with insufficient discharge output characteristics due to limitations in their separator designs, which affect safety and performance.
Innovation Solution
The introduction of an insulating porous layer with specific capacitance and thickness ranges, containing fine metal oxide particles like titanium oxide and aluminum, improves the discharge output characteristic by optimizing the desolvation process of cations, thereby enhancing the battery's performance and safety.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a porous film made of meltable material is used as separator to provide shutdown function, then safety is improved, but discharge output characteristic deteriorates
Solution Approach 1:
The separator is constructed as a composite structure consisting of a porous base material layer and an insulating porous layer containing inorganic fine particles (such as alumina, silica, or titania) dispersed in a binder polymer. This composite structure combines the shutdown function of the porous base material with the ion conductivity and thermal stability of the insulating porous layer, thereby improving discharge output characteristic while maintaining safety
Solution Approach 2:
The insulating porous layer is designed with controlled porosity (30-80%) and specific pore structure to facilitate ion transport while providing thermal stability. The porous structure allows efficient ion passage during normal operation, improving discharge output, while the inorganic fine particles maintain structural integrity at elevated temperatures
2Reliability
If inorganic fine particles and binder polymer are used in active layer, then shutdown function is achieved, but discharge output characteristic remains insufficient
Solution Approach 1:
The invention optimizes several key parameters of the insulating porous layer: capacitance (0.01-0.5 μF/cm²), thickness (1-20 μm), porosity (30-80%), and inorganic fine particle content (10-90 wt%). By carefully controlling these parameters, the layer achieves both adequate shutdown function and improved ion conductivity for better discharge output
Solution Approach 2:
The separator structure is designed with spatial differentiation: the porous base material layer provides the shutdown function through its meltable structure, while the insulating porous layer with inorganic fine particles provides ion conductivity and thermal stability. Each layer has localized properties optimized for its specific function, resolving the contradiction between shutdown capability and discharge performance
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 implementation of the insulating porous layer with controlled capacitance and thickness improves the discharge output characteristic of nonaqueous electrolyte secondary batteries, leading to superior performance compared to conventional designs, while ensuring safety through enhanced ion management and thermal stability.
Implementation Method 1
improves the discharge output characteristic by optimizing the desolvation process of cations
Implementation Method 2
an insulating porous layer with specific capacitance and thickness ranges
Data Source
AI summary
As a nonaqueous electrolyte secondary battery insulating porous layer and nonaqueous electrolyte secondary battery laminated separator each of which allows a nonaqueous electrolyte secondary battery to have an improved discharge output characteristic, there are provided (i) a nonaqueous electrolyte secondary battery insulating porous layer containing a filler including a metal oxide and having a capacitance of not less than 0.0390 nF and not more than 0.142 nF per 19.6 mm2 and a thickness of not less than 0.1 μm and not more than 20 μm and (ii) a nonaqueous electrolyte secondary battery laminated separator including the porous layer.