Electrode Assembly Winding with Preheating to Reduce Lithium Deposition
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The existing manufacturing process of secondary battery electrode assemblies, particularly the stack/folding type, results in increased interfacial resistance and lithium deposition at non-bonded regions due to uneven thickness of the active material layer, threatening the safety and cycle characteristics of lithium secondary batteries.
Innovation Solution
A method and apparatus for manufacturing an electrode assembly where unit cells are heat-treated at the ends where tabs are formed, along with the separation film, before winding, to minimize non-bonded regions and reduce lithium deposition, using a winder and heaters to control the heat treatment and winding process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If unit cells are simply wound with separation film without heat treatment, then the manufacturing process is simple and fast, but non-bonded regions increase and interfacial resistance increases causing lithium deposition
Solution Approach 1:
Heat treatment is performed on the unit cells and separation film before the winding process. This preliminary action modifies the physical properties of the materials (making them more pliable) in advance, ensuring better bonding during winding and preventing lithium deposition, thus resolving the contradiction between manufacturing speed and battery reliability
Solution Approach 2:
The heat treatment changes the temperature parameter of the unit cells and separation film, transforming them from a rigid state to a more pliable state. This parameter change enables better conformal bonding during winding, reducing non-bonded regions and interfacial resistance, thereby improving battery safety and cycle characteristics
2Reliability
If heat treatment is applied to unit cells and separation film before winding, then bonding quality improves and lithium deposition is suppressed, but the manufacturing process becomes more complex
Solution Approach 1:
The heat treatment process combines heating the unit cells and separation film simultaneously in an integrated manner before winding. This merging of the heat treatment step into a unified process, rather than treating them separately, simplifies the overall manufacturing complexity while maintaining the bonding quality improvements
Solution Approach 2:
The heat treatment is performed continuously on both the unit cells and separation film in sequence before winding, creating a continuous preparatory action that ensures consistent bonding quality throughout the manufacturing process, reducing variability and simplifying quality control
3Manufacturing precision
If the active material layer has uniform thickness, then bonding is more uniform, but the electrode structure becomes more difficult to manufacture
Solution Approach 1:
Heat treatment changes the temperature parameter of the active material layer, making it more pliable and easier to conform to the separation film surface. This parameter change allows the irregularly shaped electrodes with varying thickness to achieve uniform bonding without requiring precise manufacturing control of the active material layer thickness
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 effectively reduces lithium deposition and enhances the safety and cycle characteristics of secondary batteries by ensuring better bonding between the unit cells and the separation film, thereby improving the overall performance and reliability of the battery.
Implementation Method 1
heat-treating one end of each of the unit cells where tabs of the unit cells are formed, another end of each of the unit cells, and the separation film positioned at a corresponding location thereof
Data Source
AI summary
An electrode assembly is manufactured in which unit cells are wound with a separation film. Unit cells are mounted on an upper surface of the separation film to prepare an array body. One end of each of the unit cells where tabs of the unit cells are formed, another end of each of the unit cells, which are in the upper and lower portions of a direction parallel to a longitudinal direction of the separation film and parallel to a winding direction of the array body, and the separation film positioned at a corresponding location thereof. The heat-treated unit cells are wound with the separation film. An apparatus manufactures the electrode assembly.