Battery Cell Injection-Hole Sealing With Annular Friction Welding
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Solution Overview
Problem
Existing battery cell sealing methods, such as laser welding and friction stir welding, face challenges with cleanliness requirements, potential for welding defects, and the need for stirring needles that can wear out, leading to suboptimal sealing performance of liquid injection holes.
Innovation Solution
A battery cell design featuring a circular ring-shaped groove around the liquid injection hole, where an annular sealing member is frictionally welded to the groove, eliminating the need for a stirring needle and reducing the risk of welding defects, with a clamping part and tool interface for improved production efficiency and safety.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If laser welding or friction stir welding is used to seal the liquid injection hole, then sealing performance can be improved, but the requirements for cleanliness of the liquid injection hole become extremely high and welding defects may occur
Solution Approach 1:
The patent extracts and eliminates the stirring needle component from the friction stir welding process, replacing it with a friction pressing member that directly presses against the groove. This removal of the stirring needle eliminates the source of welding defects and particle contamination, thereby reducing cleanliness requirements while maintaining sealing performance.
Solution Approach 2:
The patent replaces the complex friction stir welding mechanical system (including stirring needle, rotation, and stirring action) with a simpler friction pressing mechanism. The friction pressing member rotates and presses against the groove to generate friction heat and form a friction welding seam, eliminating the need for stirring needle insertion and extraction, thus reducing cleanliness requirements.
2Ease of manufacture
If friction stir welding with stirring needle is used, then welding can be achieved, but the stirring needle is consumable and will wear out, leading to production inefficiency
Solution Approach 1:
The patent inverts the disposable concept: instead of making the stirring needle disposable (which wears out), the design makes the friction pressing member disposable or replaceable while the groove structure remains permanent. The friction pressing member can be a simple, inexpensive component that is replaced when worn, eliminating the need for expensive, precision-machined stirring needles that are subject to wear and contamination.
Solution Approach 2:
The friction pressing member is designed to self-clean during the friction welding process as it rotates and presses against the groove, generating friction heat that can burn off contaminants. This self-service cleaning capability reduces the need for external cleaning operations and maintains production efficiency without requiring consumable stirring needles.
3Reliability
If conventional welding methods are used, then sealing can be achieved, but particles generated by welding will remain on the surface of the welding seam
Solution Approach 1:
The patent converts the potentially harmful friction heat and material deformation into a beneficial self-cleaning effect. The friction pressing member generates heat that burns off particles and contaminants from the groove surface during the welding process, transforming what would be harmful thermal effects into a cleaning mechanism that eliminates welding particles from the seam surface.
Solution Approach 2:
The patent extracts and eliminates the stirring needle that generates particles during friction stir welding. By using a friction pressing member that presses against the groove without inserting a stirring needle into the liquid injection hole, the source of particle contamination is removed, resulting in a cleaner welding seam surface.
4Reliability
If the sealing member protrudes from the surface of the battery cell, then sealing can be achieved, but it may cause sealing issues during transport or use
Solution Approach 1:
The patent designs the friction welding seam to be nested within the groove structure, with the friction pressing member fitting into the groove during welding. The groove acts as a recess that accommodates the sealing member and welding seam, allowing the surface to remain substantially flush with the battery cell exterior, eliminating protrusions that could cause damage during transport while maintaining sealing integrity.
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 design ensures better sealing performance, reduces the risk of leakage, and enhances production efficiency by minimizing the need for precise cleanliness and avoiding the use of consumable needles, while maintaining a flat surface and preventing protrusions that could cause sealing issues during transport or use.
Implementation Method 1
the side wall of the sealing member is frictionally welded to a bottom wall of the first groove to seal the liquid injection hole. The friction welding is friction between the sealing member and the first wall
Data Source
AI summary
A battery cell includes a first wall and a sealing member. A liquid injection hole is disposed on the first wall, a first groove in a circular ring shape is disposed around the liquid injection hole, and an opening of the first groove faces an exterior of the battery cell. The sealing member includes a bottom wall and a side wall, the bottom wall covers one end of the liquid injection hole away from an interior of the battery cell, the side wall is at least partially accommodated in the first groove, the side wall is in an annular structure, and the side wall of the sealing member is frictionally welded to a bottom wall of the first groove to seal the liquid injection holed.