Battery Cap Plate Welding Bead Structure for Pore-Free Bonding
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Solution Overview
Problem
Existing rechargeable battery welding methods struggle to achieve improved welding quality while maintaining the required bonding strength between the cap plate and the case, often resulting in pores or spatter.
Innovation Solution
A rechargeable battery design featuring a welding bead part with a first region and a second region on its cross-section, where the first region has a deeper depth and the second region has a wider width, formed using a keyhole welding method for the first region and a conduction welding method for the second region.
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 is achieved, but welding quality deteriorates due to pores or spatter
Solution Approach 1:
The welding bead part is segmented into two distinct regions: a first region with deeper depth and a second region with wider width. This segmentation allows each region to serve different functions - the first region provides strong bonding penetration while the second region prevents harmful factors like pores and spatter, thereby resolving the contradiction between bonding force and welding quality
Solution Approach 2:
Different regions of the welding bead part are given different local qualities - the first region has deeper depth for strong bonding, while the second region has wider width for quality control. This local differentiation enables the welding structure to simultaneously achieve both bonding strength and high welding quality without pores or spatter
2Strength
If welding parameters are increased to improve bonding strength, then bonding force is enhanced, but welding quality deteriorates due to increased pores or spatter
Solution Approach 1:
The welding bead is segmented into two regions with different characteristics. The first region provides the necessary bonding strength through deeper penetration, while the second region maintains welding quality by having wider width that prevents pore and spatter formation, thus resolving the contradiction between strength and quality
Solution Approach 2:
The welding structure utilizes parameter changes by creating regions with different depth and width characteristics. This parameter differentiation allows the welding bead to simultaneously achieve high bonding strength through the deeper first region and high welding quality through the wider second region, eliminating the need to increase overall welding parameters that would cause defects
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 enhances welding quality and effectively satisfies the required bonding strength between the cap plate and the case, while minimizing the occurrence of pores or spatter.
Implementation Method 1
forming a welding bead part by welding a contact surface between the cap plate and the case along a circumference of the cap plate
Data Source
AI summary
A rechargeable battery includes a case having an opening and accommodating an electrode assembly therein; a cap plate closing and sealing the opening; and a welding bead part along a circumference of the cap plate and at a contact surface of the case and the cap plate, wherein the welding bead part includes first and second regions 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 between end parts of the first boundary line, the second region has a second boundary line on the cross-section, the first region is between end parts of the second boundary line to form first and second contact points in contact with the first boundary line, the first region is deeper than the second region, and the second region is wider than the first region.