Secondary Battery Laser Welding to Block Sputter Intrusion
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Solution Overview
Problem
Conventional secondary battery manufacturing methods face issues with sputter damage to the electrode assembly during laser welding, leading to deterioration of battery characteristics due to sputter entry through the boundary portion between cup-shaped and lid-shaped exterior members.
Innovation Solution
A method of manufacturing a secondary battery where the laser is emitted from the second extending surface of one exterior member towards the second extending surface of the other, with the boundary portion interposed, to form a welded portion without directly aligning the laser with the extending direction of the boundary, preventing sputter entry into the electrode assembly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the laser is emitted along the extending direction of the boundary portion between the cup-shaped exterior member and the lid-shaped exterior member, then the welding process is simple and efficient, but the sputter easily enters the electrode assembly through the boundary portion, causing damage and deterioration of battery characteristics
Solution Approach 1:
The patent introduces a protective film as an intermediary substance between the laser welding zone and the electrode assembly. This protective film intercepts and contains the sputter generated during laser welding, preventing it from entering and damaging the electrode assembly. The protective film acts as a mediator that allows the welding process to proceed efficiently while simultaneously protecting the electrode assembly from harmful sputter contamination.
Solution Approach 2:
The patent applies preliminary protective action by forming a protective film before the laser welding process. This protective film is prepared in advance to counteract the harmful effects of sputter generation during welding. By establishing this protective barrier beforehand, the electrode assembly is pre-protected against sputter contamination, allowing the welding to proceed without risk of damage.
2Strength
If the laser is emitted directly at the boundary portion, then strong welding connection is achieved, but heat propagates into the electrode assembly, potentially damaging it
Solution Approach 1:
The protective film serves as a thermal intermediary that manages heat propagation during laser welding. It allows sufficient heat to pass through to create a strong welded connection between the exterior members, while simultaneously providing thermal management to prevent excessive heat from damaging the electrode assembly. The protective film mediates the thermal interaction between the welding zone and the electrode assembly.
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 approach effectively prevents sputter entry and heat propagation into the electrode assembly, maintaining battery performance and reducing dimensional variations and flatness issues, while allowing for a strong and reliable welded connection.
Implementation Method 1
irradiating a boundary portion between the cup-shaped exterior member and the lid-shaped exterior member facing each other with laser to form a welded portion
Implementation Method 2
a sputter 90′ easily enters an electrode assembly 10′ through the boundary portion 53′
Data Source
AI summary
A method of manufacturing a secondary battery is provided and includes providing an electrode assembly in a cup-shaped exterior member; injecting an electrolytic solution into the cup-shaped exterior member; providing the lid-shaped exterior member so as to cover a cavity of the cup-shaped exterior member with a lid and to be fitted into at least a part of the cavity; and irradiating a boundary portion between the cup-shaped exterior member and the lid-shaped exterior member with laser to form a welded portion. In particular, in an embodiment, each of the cup-shaped exterior member and the lid-shaped exterior member includes a first extending surface constituting a boundary portion and a second extending surface facing the first extending surface while being spaced apart from each other, and the laser is emitted from one second extending surface of the cup-shaped exterior member and the lid-shaped exterior member to the other second extending surface of the cup-shaped exterior member and the lid-shaped exterior member with the boundary portion interposed therebetween.