Porous Current Collector Anode for Lithium Metal Batteries
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Solution Overview
Problem
Current lithium metal battery manufacturing processes face challenges in producing extremely thin lithium foil layers, especially with widths greater than 55 mm, due to the soft and reactive nature of lithium, leading to low yield and high costs, which limits the energy capacity and cycle life of secondary lithium metal batteries.
Innovation Solution
A method involving a porous current collector with a webbed structure and high open area, allowing alkali metal foil to be laminated to one side and extruded through openings to fill volumes, enabling the use of thicker and wider alkali metal foils, increasing energy density and cycle life while reducing production costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If traditional roll-milling processes are used to produce thin lithium foil, then lithium foil can be manufactured, but the yield is low and cost is high due to the soft and reactive nature of lithium
Solution Approach 1:
A carrier film is introduced as an intermediary substrate to support the lithium foil during manufacturing and handling. The carrier film provides mechanical strength and stability, enabling the production of thin lithium foil layers without direct handling of the soft and reactive lithium material, thereby improving yield and reducing costs.
Solution Approach 2:
The current collector is designed with a porous structure that allows lithium to be deposited and extruded through the substrate. This porous architecture enables better control over lithium foil formation and thickness, improving manufacturing precision while maintaining high productivity through enhanced lithium utilization.
2Quantity of substance
If the thickness of lithium foil is decreased to increase energy density, then volumetric and gravimetric energy density improve, but manufacturing challenges increase and yield decreases
Solution Approach 1:
The carrier film acts as a mediator that enables the manufacturing of ultra-thin lithium foil layers (e.g., ≤20 μm) by providing structural support during production. This allows achieving high energy density with thin lithium while maintaining ease of manufacture through the carrier film's mechanical properties.
Solution Approach 2:
The invention changes the manufacturing parameters by using carrier film-supported lithium deposition instead of traditional direct rolling. This parameter change enables production of thinner lithium foil with improved yield and reduced manufacturing difficulty.
3Ease of manufacture
If the maximum width of lithium metal foil is restricted by manufacturing processes, then production cost is reduced, but the areal dimensions of battery cells are limited
Solution Approach 1:
The battery cell design is segmented into multiple regions with lithium foil applied to both sides of the current collector in a segmented pattern. This segmentation allows using standard-width lithium foil while achieving larger effective battery cell areas through strategic placement and folding configurations.
Solution Approach 2:
The invention utilizes three-dimensional folding and stacking arrangements of the current collector and lithium foil layers. This dimensional transformation allows converting limited two-dimensional foil width into expanded three-dimensional battery cell volume and effective area.
4Productivity
If lithium foil thickness is increased to improve manufacturability, then manufacturing yield improves, but volumetric and gravimetric energy density decrease
Solution Approach 1:
The carrier film enables the use of optimally thin lithium foil (e.g., 20-40 μm) by providing manufacturing support, achieving both high productivity through improved yield and high volumetric energy density through minimal lithium thickness. The carrier film mediates between these conflicting requirements.
Solution Approach 2:
The porous current collector structure enhances lithium utilization efficiency, allowing thinner lithium foil to achieve the same effective capacity. This porous architecture provides mechanical support and electrical conductivity while minimizing the volume occupied by non-active materials, thereby improving volumetric energy density.
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
This approach enables the production of lithium metal batteries with higher volumetric and gravimetric energy density and extended cycle life, using more commonly available and cost-effective alkali metal foils, while allowing for larger cell dimensions and improved electrical conductivity.
Implementation Method 1
forming extruded portions of the alkali metal foil that extend through the openings from the first side to the second side and that substantially fill the volumes of the openings
Data Source
AI summary
Alkali metal secondary batteries that include anodes constructed from alkali metal foil applied to only one side of a porous current collector metal foil. Openings in the porous current collectors permit alkali metal accessibility on both sides of the anode structure. Such anode constructions enable the utilization of lower-cost and more commonly available alkali metal foil thickness, while still achieving high cell cycle life at a significantly reduced cost. Aspects of the present disclosure also include batteries with porous current collectors having increased volumetric and gravimetric energy densities, and methods of manufacturing anodes with porous current collectors.