Non-Woven Solid Electrolyte Support for Low-Resistance Li-Ion Batteries
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Solution Overview
Problem
Existing solid electrolyte layers in all-solid-state batteries face challenges with high internal resistance due to insufficient permeability of the electrolyte into the support body, leading to increased resistance and potential short circuits, while conventional support bodies either have low strength or high internal resistance.
Innovation Solution
A support body with a non-woven fabric configuration having air permeability between 1 to 50 L/cm2/min, thickness of 5 to 30 μm, and density of 0.15 to 0.45 g/cm3 is used, enhancing the permeability and physical strength to ensure uniform electrolyte filling and reduce internal resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the thickness of the solid electrolyte layer is increased to prevent short circuits, then reliability is improved, but energy density decreases and internal resistance increases
Solution Approach 1:
The support body is designed as a porous non-woven fabric with controlled porosity (30-80%) and specific pore size distribution (0.1-10 μm). This porous structure allows the solid electrolyte to penetrate deeply and uniformly throughout the support body, creating extensive ion conduction pathways. As a result, a thin layer (5-30 μm) can achieve both short circuit prevention through physical separation and low internal resistance through efficient ion transport, eliminating the need for thicker layers that would reduce energy density.
Solution Approach 2:
The invention creates a composite structure combining the support body (non-woven fabric made of polyolefin or aramid fibers) with the solid electrolyte material. The support body provides mechanical strength, dimensional stability, and short circuit prevention, while the solid electrolyte fills the porous network to provide ion conduction. This composite approach allows the thin layer (5-30 μm) to simultaneously achieve reliability (short circuit prevention) and low internal resistance, avoiding the energy density penalty associated with thicker layers.
2Loss of energy
If the thickness of the solid electrolyte layer is decreased to improve energy density, then energy density improves, but internal resistance increases and short circuits may occur
Solution Approach 1:
The porous non-woven fabric support body with optimized porosity (30-80%) and pore size (0.1-10 μm) enables the solid electrolyte to form a continuous, uniform network throughout the thin layer structure. This ensures that even at reduced thickness (5-30 μm), the solid electrolyte maintains adequate ion conduction pathways and physical separation between electrodes, achieving both low internal resistance and high energy density.
Solution Approach 2:
The composite of support body and solid electrolyte creates a structurally sound thin layer where the support body's mechanical properties prevent short circuits while the solid electrolyte's porous infiltration ensures low internal resistance. This composite structure enables the thin layer (5-30 μm) to simultaneously achieve high energy density and low internal resistance, resolving the contradiction between thickness reduction and performance maintenance.
3Loss of energy
If a thin-film-shaped support body is used to achieve thin solid electrolyte layer, then energy density improves, but manufacturing precision deteriorates due to strain and cracking during drying
Solution Approach 1:
The porous non-woven fabric structure acts as a strain-absorbing matrix during the drying process. The porous network accommodates volume changes and stress distribution, preventing the formation of cracks that would compromise uniformity. This allows the thin solid electrolyte layer to be formed uniformly (5-30 μm thickness) without manufacturing defects, achieving both high energy density and manufacturing precision.
Solution Approach 2:
The invention optimizes key parameters of the support body including porosity (30-80%), pore size (0.1-10 μm), thickness (5-30 μm), and fiber composition to create a structure that is mechanically robust yet permeable. These parameter optimizations enable the support body to maintain structural integrity during drying, prevent cracking, and ensure uniform solid electrolyte distribution, thereby achieving both thin layer formation and manufacturing precision.
4Reliability
If the porosity of the support body is increased to improve electrolyte permeability, then internal resistance decreases, but strength deteriorates
Solution Approach 1:
The non-woven fabric support body utilizes a controlled porous structure with porosity optimized between 30-80% and pore sizes of 0.1-10 μm. This specific porosity range creates sufficient void space for solid electrolyte penetration (reducing internal resistance) while maintaining adequate fiber density and inter-fiber bonding to preserve mechanical strength. The porous architecture allows electrolyte access without compromising structural integrity.
Solution Approach 2:
The composite structure of support body fibers and solid electrolyte creates a synergistic system where the fiber network provides mechanical strength even at optimized porosity levels (30-80%), while the solid electrolyte filling the pores provides ion conduction. This composite approach allows the support body to simultaneously achieve low internal resistance (through adequate porosity) and high strength (through fiber network integrity), resolving the contradiction between permeability and mechanical properties.
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 support body design achieves a solid electrolyte layer with low internal resistance and improved physical strength, reducing impedance and enhancing the battery's discharge capacity while preventing short circuits.
Implementation Method 1
the non-woven fabric has an air permeability in a range of 1 to 50 L/cm2/min, a thickness in a range of 5 to 30 μm, and a density in a range of 0.15 to 0.45 g/cm3
Data Source
AI summary
A support body included in the solid electrolyte layer of the lithium ion secondary battery is constituted by a non-woven fabric having an air permeability in a range of 1 to 50 L/cm2/min, a thickness in a range of 5 to 30 μm, and a density in a range of 0.15 to 0.45 g/cm3.