Battery Cap Plate Welding Structure for Spatter and Corrosion Control
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Solution Overview
Problem
Existing secondary batteries face issues with safety due to spatter generation during welding and potential corrosion at welding points, which can compromise the integrity and performance of the battery.
Innovation Solution
The secondary battery design includes an outer surface welding process for the cap and case, using a first and second current collector plates with a stepped portion and elastic deformation, and employs a corrosion preventer to cover the welding points, preventing spatter entry and corrosion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If welding is performed on the cap plate to connect current collector plates and case, then electrical connection and structural integrity are improved, but spatter generation and corrosion risk increase
Solution Approach 1:
A groove is formed in the cap plate at the welding position before welding occurs. This preliminary structural preparation creates a containment feature that prevents spatter from entering the battery interior during the welding process, thereby resolving the contradiction between achieving reliable welding connections and preventing harmful spatter entry.
Solution Approach 2:
A corrosion preventer is applied to the welding portion after welding. This intermediary protective layer acts as a barrier between the welding area and the electrolyte, preventing corrosion at the welding points while maintaining the electrical connection integrity. This resolves the contradiction by introducing a protective mediator that eliminates the harmful effect of corrosion.
2Adaptability or versatility
If the first current collector plate is made elastically deformable to accommodate height differences, then adaptability to electrode assembly variations is improved, but structural rigidity decreases
Solution Approach 1:
The first current collector plate is designed with elastic deformability, allowing it to dynamically adapt to height differences between electrode plates through controlled deformation. The plate can bend to accommodate variations while maintaining electrical contact, yet retains sufficient structural strength to perform its connecting function. This dynamic flexibility resolves the contradiction between adaptability and rigidity.
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
The design enhances safety by preventing spatter entry and reducing corrosion, improving sealing strength and capacity while maintaining a stable electrical connection.
Implementation Method 1
the first current collector plate may include a first region in contact with the first electrode plate, and a second region in contact with the cap plate, and be elastically deformably bent such that the first region has a height difference with respect to the second region
Implementation Method 2
a corrosion preventer covering at least one of the first welding portion and the second welding portion
Data Source
AI summary
A secondary battery includes: an electrode assembly including a first electrode plate, a second electrode plate, and a separator; a case including a first side having an opening to accommodate the electrode assembly; a cap plate sealing the first side of the case; a first current collector plate arranged between the electrode assembly and the cap plate and electrically connecting the first electrode plate and the cap plate; a terminal arranged on a second side of the case; a second current collector plate electrically connecting the second electrode plate and the terminal; a first welding portion on an outer surface of the cap plate and welding the cap plate and the first current collector plate; and a second welding portion on the outer surface of the cap plate and welding the case and the cap plate.