Electrode Tab Guide Alignment for Low-Tension Ultrasonic Welding
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Solution Overview
Problem
Existing welding technologies for electrode tabs in lithium secondary batteries apply excessive tensile force, leading to potential fracture and damage during alignment and assembly, which compromises the safety and longevity of the electrode assembly.
Innovation Solution
A welding apparatus and method using guides to align and loosen electrode tabs before welding, reducing tensile force by employing movable guides with rotary portions to extend the length of electrode tabs, ensuring they are not tightly aligned, and using ultrasonic welding to form a stable weld.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If electrode tabs are tightened during alignment to form the electrode tab bundle, then alignment precision is improved, but the electrode tabs become prone to fracture under small impact
Solution Approach 1:
The patent applies preliminary action by performing alignment of electrode tabs before welding, using a guide structure that maintains proper positioning without requiring excessive tightening force. The guide holes and guide portions work together to align tabs in advance, allowing subsequent welding to secure the alignment without subjecting tabs to continuous high tensile stress that would cause fracture.
2Ease of manufacture
If electrode tabs are aligned and welded, then the electrode tab bundle is formed, but tensile force causes the electrode tabs to be stretched and safety is lowered
Solution Approach 1:
The patent introduces an intermediary guide structure consisting of guide holes in the lower electrode assembly and guide portions on the upper electrode tabs. This intermediary mechanism facilitates proper alignment and bonding of electrode tabs during manufacturing while minimizing the tensile force required, thereby maintaining electrode tab safety and preventing stretching that would compromise reliability.
3Object-affected harmful factors
If loads are applied to prevent dust movement during pre-welding, then contamination is reduced, but tensile force stretches the electrode tabs and lowers safety
Solution Approach 1:
The patent extracts the dust prevention function from the loading process by implementing a guide structure that aligns electrode tabs through guide holes and guide portions. This separation allows dust control to be achieved through proper alignment and bonding mechanisms rather than relying on loads that would subject electrode tabs to harmful tensile forces, thereby maintaining safety while preventing contamination.
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 prevents electrode tab fracture and breakage, maintaining tab length and stability during charging and discharging cycles, thereby enhancing the safety and durability of the electrode assembly.
Implementation Method 1
a welding unit configured to weld the electrode tabs in the state in which the guides have aligned the electrode tabs
Data Source
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AI summary
The present invention relates to a welding apparatus including an electrode assembly configured such that a plurality of positive electrodes and a plurality of negative electrodes are stacked in the state in which separators are interposed therebetween, guides configured to reduce tensile force of positive electrode tabs and negative electrode tabs protruding from the electrode assembly, an anvil configured to allow the electrode tabs to be disposed thereon, and a horn configured to apply ultrasonic waves to the electrode tabs disposed on the anvil, a welding method using the same, and an electrode assembly manufactured by the welding method.