Hierarchical Laser-Textured Current Collector for Battery Delamination
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Solution Overview
Problem
Current current collector foils in rechargeable batteries, particularly in lithium ion batteries, face issues with mechanical and electrical bonding of electrode layers, leading to delamination due to volume changes and poor surface roughness, which affects the life and cycling stability of batteries.
Innovation Solution
An electrically conductive base material with a hierarchical surface structure, created using ultrashort pulse laser radiation, that allows for improved adhesion of multiscale particles and reduces delamination by forming suitable coupling structures and capillary transport structures, enhancing the bonding between the electrode material and the current collector.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If current collector foils with homogeneous surfaces are used, then the manufacturing process is simple, but the bonding strength between electrode layer and current collector is insufficient
Solution Approach 1:
The surface of the current collector is segmented into multiple hierarchical levels of structures (microstructures and nan structures), creating diverse bonding interfaces that enhance mechanical interlocking with electrode particles while maintaining manufacturing feasibility through controlled surface treatment processes
Solution Approach 2:
Different regions of the current collector surface are given different local structures (microstructures and nan structures with specific roughness parameters) to optimize bonding in specific areas, allowing the surface to have tailored properties for electrode adhesion while keeping the bulk material simple and manufacturable
2Reliability
If conventional current collector surfaces are used, then the production process is straightforward, but delamination occurs due to volume changes
Solution Approach 1:
The current collector surface is pre-treated to create hierarchical micro and nan structures before electrode coating, establishing a robust bonding foundation that anticipates and accommodates future volume changes during battery cycling, thereby preventing delamination without requiring complex post-processing
Solution Approach 2:
The hierarchical surface structures act as a cushioning layer that absorbs and distributes the stress from electrode volume changes during charging and cycling, preventing the propagation of delamination while keeping the current collector itself structurally simple and easy to manufacture
3Strength
If homogeneous current collector surfaces are used, then manufacturing is simple, but adhesion to multiscale particles is poor
Solution Approach 1:
The surface is modified by adding hierarchical structures in the vertical dimension (microstructures and nan structures creating depth and complexity), transforming a simple 2D homogeneous surface into a multi-dimensional rough surface that enhances particle adhesion while maintaining compatibility with standard manufacturing processes
4Reliability
If copper foil is used as current collector, then electrical conductivity is good, but chemical degradation and swelling are pronounced
Solution Approach 1:
The surface parameters of the copper foil are changed by creating hierarchical micro and nan structures through controlled treatment processes, modifying the surface properties to resist chemical degradation and swelling while maintaining the bulk electrical conductivity and keeping the treatment process manageable
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 hierarchical surface structure improves the mechanical and electrical bonding of electrode layers, increasing the cycling life and stability of rechargeable batteries, allowing for more flexible cell designs and reducing solvent usage in the coating process, thereby enhancing production throughput.
Implementation Method 1
the surface of the base material provided for receiving the electrically conductive particles is configured in such a manner that it has a hierarchical structure which is created using ultrashort pulse laser radiation
Implementation Method 2
forming suitable coupling structures and capillary transport structures, enhancing the bonding between the electrode material and the current collector
Data Source
AI summary
The invention relates to an electrically conductive base material (112) for receiving a coating material (114) which comprises electrically conductive particles (116), a method for the production thereof and the use thereof as current collector for an electrode material comprising electrically conductive particles. The base material (112) comprises a metal foil, wherein at least one surface (118) of the base material (112) provided for receiving the electrically conductive particles (116) has a first structure (120) and a second structure (122), wherein the first structure (120) has first ridges (124) and/or first grooves (126) relative to the surface (118) of the base material (112) and wherein the second structure (122) has second ridges (128) and/or second grooves (130) relative to the surface (132) of the first structure (120). Herein, the first ridges (124) and/or the first grooves (126) have first dimensions, wherein the second ridges (128) and/or the second grooves (130) have second dimensions, wherein the first dimensions exceed the second dimensions by a factor of at least 10.The invention further relates to an electrically conductive layer composite (110) which comprises the base material (112) and a coating material (114) comprising electrically conductive particles (116), a method for the production thereof and the use thereof in a secondary element of a rechargeable battery, in particular in a lithium ion battery. Herein, the particles (116) in the coating material (114) adhere to first ridges (124) and/or to first grooves (126) in a first structure (120) on the surface (118) of the base material (112) and/or to second ridges (128) and/or to second grooves (130) in a second structure (122) on the surface (132) of the first structure (120). A good bonding of the coating material (114) to the base material (112) reduces or prevents a layer delamination of the coating material (114) from the base material (112).