Battery Shell Necking with Preformed Annular Groove Control
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Solution Overview
Problem
Existing battery production technologies, particularly cylindrical battery winding sealing methods, frequently experience short circuit faults due to excessive deformation of the shell during the necking process, which compromises the stability and safety of the battery cells.
Innovation Solution
A necking method and apparatus that first form a narrower annular groove on the shell before expanding it to create the necked portion, limiting deformation and preventing excessive pressure on the electrode assembly, thereby reducing the risk of short circuits and improving machining precision and structural stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the necked portion is directly formed on the shell, then the packaging speed is improved, but the shell undergoes large compression deformation and squeezes the electrode assembly causing short circuit faults
Solution Approach 1:
The patent applies preliminary action by first forming an annular groove on the shell before forming the necked portion. This preliminary groove formation creates a controlled deformation zone that prevents excessive compression deformation during subsequent necking, thereby avoiding electrode assembly damage while maintaining packaging speed.
Solution Approach 2:
The necking process is segmented into two distinct stages: first forming an annular groove, then forming the necked portion. This segmentation allows the deformation to be controlled and distributed, preventing concentrated stress that would cause short circuits while maintaining efficient packaging speed.
2Device complexity
If the necked portion is directly formed on the shell, then the manufacturing process is simplified, but the machining precision and structural stability of the necked portion deteriorate
Solution Approach 1:
The annular groove is formed as a preliminary step before the final necked portion formation. This preliminary action creates a pre-defined deformation zone that guides subsequent forming, ensuring precise necking dimensions and improved structural stability without significantly increasing overall process complexity.
Solution Approach 2:
The annular groove creates a localized zone with different mechanical properties compared to the rest of the shell. This local quality change concentrates deformation in a controlled area, improving the precision of the necked portion while maintaining overall process simplicity.
3Shape
If the width of the annular groove is expanded towards the open end to form the necked portion, then the desired necking shape is achieved, but the deformation area of the shell expands towards the electrode assembly
Solution Approach 1:
The annular groove is formed in advance before expanding the width to create the necked portion. This preliminary groove acts as a barrier that confines deformation to a specific area, preventing deformation from propagating towards the electrode assembly while still achieving the desired necking shape.
Solution Approach 2:
The pre-formed annular groove creates preliminary resistance against deformation propagation. This preliminary anti-action blocks the transmission of pressure waves and deformation forces, protecting the electrode assembly from harmful effects while allowing the necked portion to achieve its target shape.
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 effectively reduces short circuit faults and enhances the safety and stability of battery cells by controlling shell deformation and maintaining the integrity of the electrode assembly during the necking process.
Implementation Method 1
a first roller, configured to feed in a radial direction of the shell to form an annular groove on the shell
Implementation Method 2
a second roller, configured to feed in a radial direction of the shell to form a necked portion and a flanged portion on the shell
Data Source
AI summary
The present application provides a necking method, a necking apparatus, and a battery manufacturing device. The necking method is used for forming a necked portion on a shell with an open end. The necking method includes: forming an annular groove on the shell, where the annular groove extends in a circumferential direction of the shell; and expanding a width of the annular groove towards the open end to form the necked portion. The technical solution of the present application can effectively reduce deformation of the shell, ensure safety of an electrode assembly, and improve performance stability of a battery cell. Meanwhile, pre-necking the shell effectively reduce a risk of deformation resilience of the shell after the necked portion is formed, thereby improving machining precision and structural stability of the necked portion.