Slitted Battery Winder Mandrel for Separator Hold During Winding
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The existing mandrel members used in manufacturing jelly roll-type electrode assemblies for secondary batteries suffer from a separator loosening issue during the reform process, leading to poor electrode tab welding quality, particularly as separators become thinner and mandrel sizes decrease.
Innovation Solution
A mandrel member with a hollow cylindrical body featuring slits oriented at an inclination to the radial direction, allowing air to be supplied through the hollow portion and ejected in a tangential direction via the Coanda effect, ensuring the sheet-type stack is securely attached to the mandrel during winding, eliminating the need for a separate reform process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a traditional solid mandrel is used for winding the sheet-type stack, then the mandrel provides structural support, but the separator loosens during the reform process leading to poor welding quality
Solution Approach 1:
The patent applies pneumatic principles by introducing air supply holes that extend along the axial direction of the mandrel. Compressed air is supplied through these holes to the separator during the winding process, creating pneumatic pressure that secures the separator to the mandrel surface. This pneumatic attachment prevents separator loosening during the reform process and ensures stable electrode tab positioning for high-quality welding, resolving the contradiction between structural support and welding precision.
2Volume of moving object
If the mandrel size is decreased to accommodate thinner separators, then the battery becomes more compact, but the separator loosening problem worsens
Solution Approach 1:
The patent uses pneumatic pressure applied through air supply holes to compensate for the reduced mechanical grip of smaller mandrels. The compressed air creates sufficient pneumatic force to secure thin separators even on compact, small-sized mandrels, enabling the use of thinner separators for more compact battery designs without sacrificing separator attachment reliability.
Solution Approach 2:
The patent changes the physical state and pressure parameters of air introduced through the air supply holes. By controlling air pressure and flow rate, the system adapts to different mandrel sizes and separator thicknesses, maintaining reliable separator attachment across various compact configurations.
3Reliability
If air is supplied through the hollow portion of the mandrel, then the sheet-type stack is securely attached during winding, but additional manufacturing complexity is introduced
Solution Approach 1:
The mandrel is designed with multi-functionality: it serves as both the structural core for winding and as an air supply conduit. The hollow interior of the mandrel, which would otherwise be empty space, is utilized as an air passage to deliver compressed air to the separator. This eliminates the need for separate air delivery mechanisms and integrates the pneumatic attachment function into the existing mandrel structure, reducing overall system complexity.
Solution Approach 2:
The mandrel incorporates air supply holes that create a controlled porous structure along its axial length. This porous design allows selective air passage while maintaining the mandrel's structural integrity and rotational functionality, achieving secure separator attachment without excessive complexity.
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 solution prevents separator loosening and ensures secure attachment of the sheet-type stack, improving the quality of electrode tab welding by maintaining the integrity of the jelly roll-type electrode assembly throughout the manufacturing process.
Implementation Method 1
allowing air to be supplied through the hollow portion and ejected in a tangential direction via the Coanda effect, ensuring the sheet-type stack is securely attached to the mandrel during winding
Data Source
Figure 1A
Figure 1B
Figure 2
AI summary
A mandrel member (100) of a winder for a secondary battery, which is mounted in a winder configured to manufacture a jelly roll-type electrode assembly by winding a stack of a first electrode plate (21), a separator (22), and a second electrode plate (23), the mandrel member (100) comprising a cylindrical body having a hollow portion (120), wherein the cylindrical body includes a plurality of slits (110) crossing the cylindrical body in a hollow axis direction so that the hollow portion (120) inside the cylindrical body is in fluid communication with the outside of the cylindrical body.