Battery Cap Plate Welding Bead Structure for Pore and Spatter Control
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Solution Overview
Problem
Existing rechargeable battery welding methods face challenges in achieving improved welding quality while maintaining the required bonding strength between the cap plate and the case, often resulting in pores or spatter formation.
Innovation Solution
A welding method that forms a welding bead with a first region of deeper depth and a second region of wider width, using a keyhole welding method for the first region and conduction welding for the second region, with the second laser beam irradiated simultaneously and asymmetrically to enhance bonding strength and reduce spatter formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional welding methods are used to bond the cap plate to the case, then bonding force can be achieved, but welding quality deteriorates due to pores or spatter formation
Solution Approach 1:
The welding bead part is divided into two distinct regions: a first region with deeper depth for strong bonding, and a second region with wider width for suppressing pores and spatter. This segmentation allows each region to perform its specific function optimally, resolving the contradiction between bonding strength and welding quality.
Solution Approach 2:
Different regions of the welding bead part are given different properties: the first region has deeper depth (30-60% penetration) for strong bonding force, while the second region has wider width for suppressing harmful factors. This local differentiation of properties allows simultaneous achievement of bonding strength and welding quality.
2Strength
If deeper welding depth is achieved to improve bonding strength, then bonding force increases, but welding quality worsens due to increased pores and spatter
Solution Approach 1:
The welding bead is segmented into a first region providing deep penetration (30-60%) for bonding strength, and a second region providing wider coverage for quality control. This segmentation resolves the trade-off by distributing functions across different spatial zones.
Solution Approach 2:
The solution moves from a single-dimensional welding parameter (depth) to a two-dimensional structure (depth and width distribution). By controlling both the depth profile (first region) and width profile (second region), the patent achieves simultaneous optimization of bonding strength and welding quality.
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 improves welding quality and bonding strength between the cap plate and the case, suppressing the occurrence of pores and spatter, thereby enhancing the overall performance and reliability of the rechargeable battery.
Implementation Method 1
a first laser beam forming a keyhole welding part by keyhole welding
Implementation Method 2
the first laser beam forming a keyhole welding part by keyhole welding
Implementation Method 3
a second laser beam forming a conduction welding part by conduction welding
Implementation Method 4
a second laser beam forming a conduction welding part by conduction welding
Data Source
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AI summary
A rechargeable battery and a welding method of a rechargeable battery are disclosed, and a rechargeable battery according to an exemplary embodiment of the present invention includes: a case in which an electrode assembly is accommodated in an inner space and one side is opened; a cap plate closing and sealing one surface of the case; and a welding bead part formed along a circumference of the cap plate and formed at a contact surface of the case and the cap plate, wherein the welding bead part includes a first region and a second region on a cross-section vertical to a welding progressing direction of the welding bead part, the first region has a first boundary line on the cross-section, a contact surface is disposed between both end parts of the first boundary line, the second region has a second boundary line on the cross-section, the first region is disposed between both end parts of the second boundary line to form a first contact point and a second contact point in contact with the first boundary line, the first region has a deeper depth than the second region, and the second region has a wider width than the first region.