Solid Electrolyte Lithium Battery Separator Design
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Solid-state lithium batteries face limitations in charging density due to dendrite growth through separators, leading to potential short circuits, and existing solutions to prevent dendrite growth are costly and complex to produce.
Innovation Solution
A solid-state lithium battery design featuring a thicker first separator layer with a sulfidic solid electrolyte and a thinner, low-porosity second separator layer with a sulfide solid electrolyte, where the second layer is between the anode and the first layer, preventing dendrite growth while maintaining cost-effectiveness and simplicity in production.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single thick separator layer is used to prevent dendrite growth, then dendrite penetration is reduced, but the battery charging density is limited and production cost increases
Solution Approach 1:
The separator is divided into two distinct layers: a first separator layer (5-20 μm thick) with higher porosity for ion transport, and a second separator layer (1-5 μm thick) with lower porosity for dendrite blocking. This segmentation allows each layer to perform its specialized function optimally, preventing dendrites while maintaining high charging density capability.
Solution Approach 2:
Different regions of the separator structure are assigned different properties: the first separator layer has higher porosity (30-50%) to facilitate lithium ion diffusion and support high charge densities, while the second separator layer has lower porosity (10-30%) to physically block dendrite growth. This local differentiation of properties resolves the contradiction between ion transport and dendrite prevention.
2Reliability
If separator thickness is increased to prevent dendrites, then dendrite growth is reduced, but manufacturing cost and complexity increase
Solution Approach 1:
The separator is segmented into two functional layers with distinct thicknesses and properties, allowing optimal dendrite prevention without requiring excessive total thickness. The thin second layer (1-5 μm) provides dendrite blocking, while the first layer provides structural support and ion transport, achieving reliability without oversizing the overall separator.
Solution Approach 2:
The invention changes the porosity parameter across different layers: the first separator layer has porosity of 30-50% for ion transport, while the second separator layer has porosity of 10-30% for dendrite blocking. This parameter differentiation allows effective dendrite prevention with optimized total thickness, reducing manufacturing complexity compared to uniform thick separators.
3Productivity
If a thin separator layer is used to enable high charging density, then charging speed improves, but dendrite growth increases
Solution Approach 1:
The separator is segmented into two layers where the thin second separator layer (1-5 μm) with reduced porosity (10-30%) specifically blocks dendrites, while the thicker first separator layer (5-20 μm) with higher porosity (30-50%) maintains ion transport for high charging density. This segmentation enables thin overall design without sacrificing dendrite prevention.
Solution Approach 2:
The second separator layer locally provides enhanced dendrite-blocking quality through reduced porosity (10-30%), while the first separator layer provides ion-transport quality through higher porosity (30-50%). This local quality differentiation allows the separator to be thin overall while maintaining both high charging density capability and dendrite prevention.
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
Enables high charge densities without dendrite growth, allowing for rapid charging and extended battery life while keeping production costs low, as the second separator layer's complexity is offset by the thicker, more economical first layer.
Implementation Method 1
the porosity of the second separator layer being in a range from about 0% to about 4%, preferably in a range from about 0% to about 3%, particularly preferably in a range from about 0% to about 1%
Implementation Method 2
The class of sulphide or sulphur-based solid electrolytes offers high ion conductivity
Data Source
Figure 1
AI summary
The invention relates to a lithium solid-state battery (1) comprising: a lithium anode (10); a cathode (20); a first separator layer (30) for electrically separating the lithium anode (10) from the cathode (20), the first separator layer (30) having a sulfide solid-state electrolyte; and a second separator layer (40) for electrically separating the lithium anode (10) from the cathode (20), the second separator layer (40) being arranged between the first separator layer (30) and the lithium anode (10) and the second separator layer (40) having a sulfide solid-state electrolyte, the first separator layer (30) being arranged between the cathode (20) and the second separator layer (40) and having a larger layer thickness than the second separator layer (40), the first separator layer (30) having in particular a layer thickness which is at least double the size of the second separator layer (40), the first separator layer (30) preferably having a layer thickness at least ten times the size of the second separator layer (40), the porosity of the second separator layer (40) being in a range from approx. 0% to approx. 4%, preferably in a range from approx. 0% to approx. 3%, particularly preferably in a range from approx. 0% to approx. 1%.