Tab-Less Cylindrical Li-S Cells With Carbon Edge Current Collection
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Solution Overview
Problem
Conventional lithium-sulfur batteries face issues such as polysulfide shuttle effect, leading to loss of active material, reduced cycling stability, and mechanical integrity problems due to lithium dendrite formation and cathode expansion, limiting their performance and safety for applications requiring high energy density.
Innovation Solution
A method for manufacturing a lithium-sulfur battery in a cylindrical cell format using a porous carbonaceous cathode structure with graded porosity and protective layers to inhibit polysulfide migration, combined with a jelly roll design that includes an adhesive carbon-containing layer acting as an anode tab to enhance mechanical stability and electrical conductivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional lithium-sulfur batteries are manufactured with traditional tab structures, then manufacturing process is simpler, but electrical conductivity and mechanical stability are reduced
Solution Approach 1:
The adhesive carbon-containing layer serves multiple functions: it acts as an anode tab for electrical connection, provides mechanical reinforcement to prevent cathode expansion, and maintains structural integrity during cycling. This multi-functional design eliminates the need for separate tab components while improving overall battery performance.
Solution Approach 2:
The patent combines the adhesive layer and carbon-containing material into a unified structure that serves both as structural support and electrical conductor. This merging of functions into a single component simplifies the overall battery structure while enhancing both mechanical and electrical properties.
2Device complexity
If no protective layers are used on the anode, then manufacturing process is simpler and cost is lower, but lithium dendrite formation and lithium erosion occur
Solution Approach 1:
The protective layer is applied to the anode before battery assembly and cycling begins. This preliminary protective measure prevents lithium dendrite formation and lithium erosion from the outset, ensuring long-term cycling stability and safety without requiring complex post-processing steps.
Solution Approach 2:
The protective layer acts as a cushioning barrier that anticipates and prevents harmful effects such as lithium dendrite penetration and lithium erosion. By providing this protective buffer in advance, the battery maintains structural integrity and safety throughout its operational life.
3Reliability
If porous carbonaceous cathode structure with graded porosity is used, then polysulfide migration is inhibited and cycling stability improves, but manufacturing precision requirements increase
Solution Approach 1:
The cathode structure features graded porosity where different regions have different pore sizes and distributions. This local variation in structural properties allows the cathode to effectively trap polysulfides in specific regions while maintaining overall structural integrity, thereby improving cycling stability without requiring uniform precision throughout the entire structure.
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 method improves electrical discharge performance, increases volumetric and gravimetric energy density, and enhances cycling stability by mitigating polysulfide diffusion and lithium erosion, making it suitable for high-capacity energy storage applications.
Implementation Method 1
the protective layer may include wrinkled graphene nanoplatelets adjoined to one another by flexure points
Implementation Method 2
fluorinated poly(meth)acrylates may be grafted onto some exposed carbon atoms
Implementation Method 3
disposing an adhesive carbon-containing layer along the bottom edge of the anode
Implementation Method 4
dispersing an electrolyte throughout the lithium-sulfur battery such that the electrolyte may be dispersed throughout the cathode and contact the anode
Data Source
AI summary
A method of manufacturing a lithium-sulfur battery in a cylindrical cell format is provided. In some aspects, the method includes providing an anode current collector and providing an anode on the anode current collector. The method may include depositing a protective layer on and along the length of the anode, providing a cathode current collector opposite to the anode, and providing a cathode on the cathode current collector. The method may include providing a separator between the anode and the cathode, disposing an adhesive carbon-containing layer along the bottom edge of the anode (e.g., to replace one or more conventional anode tabs), and dispersing an electrolyte throughout the lithium-sulfur battery. The method may include forming the lithium-sulfur battery in the cylindrical cell format by collectively winding into a jelly roll.