Cylindrical Battery Sealing Structure With Positive-Side Liquid Injection
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Solution Overview
Problem
Existing secondary batteries face challenges in ensuring effective sealing while minimizing the number of components and optimizing the placement of liquid injection ports, particularly on the positive electrode side, which can affect welding strength and defect detection.
Innovation Solution
A beading-free cylindrical secondary battery design with a current collector plate liquid injection portion and rivet terminal configuration that includes parallel or inclined surfaces for enhanced sealing, utilizing laser welding for secure connections and a sealing portion to cover these components, with a liquid injection port on the positive electrode side.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a liquid injection port is provided on the negative electrode side, then the sealing structure is simplified, but the welding strength is reduced and defect detection becomes difficult
Solution Approach 1:
The patent inverts the conventional approach by placing the liquid injection port on the positive electrode side instead of the negative electrode side. This inversion allows the injection port to be positioned where welding strength is less critical and defect detection is easier, while the negative electrode side maintains its simplified sealing structure.
Solution Approach 2:
The patent applies different quality requirements to different regions: the positive electrode side is designed with enhanced welding strength and defect detection capability, while the negative electrode side maintains simplified sealing. This local differentiation resolves the contradiction by optimizing each side for its specific function.
2Reliability
If multiple components are used to ensure sealing, then the sealing reliability is improved, but the number of components increases
Solution Approach 1:
The patent merges the sealing function into the cap plate itself, which integrates the sealing structure with the existing cap plate component. This eliminates the need for separate sealing components while maintaining sealing reliability, as the cap plate is designed with integrated sealing features.
Solution Approach 2:
The cap plate is designed to serve multiple functions: structural support, sealing, and electrode connection. By making the cap plate multi-functional, the patent reduces the total number of components while ensuring sealing reliability through the integrated design.
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 ensures robust sealing, reduces component count, enhances welding strength, and facilitates easy detection of welding defects, while maintaining efficient electrolyte injection and distribution.
Implementation Method 1
a sealing portion sealing the current collector plate liquid injection portion and the rivet liquid injection portion
Implementation Method 2
an upper side of the current collector plate liquid injection portion and an upper side of the rivet liquid injection portion may be coupled by laser welding
Data Source
AI summary
A secondary battery includes: a cylindrical case; an electrode assembly in the case and comprising a first tab protruding in a first direction and a second tab protruding in a second direction opposite to the first direction and connected to the case; a current collector plate in the case and comprising a current collector plate body portion connected to the first tab and a current collector plate liquid injection portion on the current collector plate body portion; a cap plate sealing the case so that the electrode assembly and the current collector plate are isolated from an outside; a rivet terminal including a rivet body portion coupled to the cap plate and a rivet liquid injection portion coupled to the current collector plate liquid injection portion; and a sealing portion sealing the current collector plate liquid injection portion and the rivet liquid injection portion.