External Terminal Step Portion for Void-Free Welding
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional power storage devices experience defective welding between collector terminals and external terminals due to the formation of voids, leading to potential fractures and reduced reliability.
Innovation Solution
The design incorporates a step portion on the external terminal with a recess and a raised portion, allowing for a secure contact surface that minimizes the formation of gaps and voids during the welding process, ensuring a robust connection between the collector terminal and external terminal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the protrusion is riveted to form a rivet portion with a swollen central portion, then the collector terminal can be mechanically connected to the external terminal, but a void is produced between the rivet portion and the plate-shaped member leading to defective welding
Solution Approach 1:
The patent applies preliminary action by forming a recess in the plate-shaped member before the riveting process. This recess is specifically designed to accommodate the swollen central portion of the rivet portion, preventing void formation during subsequent welding operations. The preparatory recess ensures that when the protrusion is riveted and swells outward, the material has a pre-formed cavity to receive it, thereby eliminating gaps that would otherwise prevent proper welding.
2Reliability
If the outer circumferential edge of the rivet portion is welded to the plate-shaped member, then electrical and mechanical connection is achieved, but the presence of a void causes welding failure
Solution Approach 1:
The recess is formed in advance in the plate-shaped member to receive the swollen rivet portion, ensuring that when welding is performed on the outer circumferential edge, there are no voids or gaps between the rivet portion and the plate-shaped member. This preliminary preparation of the recess space allows the welding process to proceed successfully, achieving both reliable electrical connection and manufacturing feasibility.
3Device complexity
If a through hole is formed in the external terminal for inserting the protrusion, then assembly is simplified, but the resulting gap between the rivet portion and external terminal surface causes welding defects
Solution Approach 1:
The patent applies local quality by creating a recess specifically at the location where the rivet portion will be formed, while maintaining the overall simplicity of the through hole structure. The recess is a localized modification to the plate-shaped member that provides precise geometric control at the critical welding interface, without complicating the overall assembly structure. This localized quality enhancement ensures proper fit and welding precision only where needed.
Solution Approach 2:
The recess is prepared in advance in the plate-shaped member before assembly and riveting occur. This preliminary action ensures that when the protrusion is inserted through the hole and riveted to form the swollen portion, the recess is already in position to accommodate the swelling, preventing gap formation and ensuring welding precision without requiring post-assembly adjustments.
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 configuration effectively suppresses the production of gaps and voids, enhancing the reliability and durability of the welding portion, thus improving the overall performance and longevity of the power storage device.
Implementation Method 1
The welding portion is formed to weld the surface of the step portion and the contact surface of the collector terminal
Data Source
AI summary
A power storage device includes an electrode assembly, an accommodation case accommodating the electrode assembly, an external terminal provided on an outer surface of the accommodation case, a collector terminal connecting the electrode assembly and the external terminal, and a welding portion connecting the collector terminal and the external terminal. The external terminal includes an opposed surface opposed to the outer surface and an outer surface located opposite to the opposed surface. The external terminal has an insertion hole extending from the opposed surface toward the outer surface and a step portion located around an opening in the insertion hole located on a side of the outer surface. The collector terminal includes a contact surface in contact with a surface of the step portion. The welding portion is formed to weld the surface of the step portion and the contact surface.