Pin-Type Anode Tab for Cylindrical Secondary Battery Assembly
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Solution Overview
Problem
The rigid nickel strips used as anode tabs in cylindrical secondary batteries often get stuck at the opening of the can during assembly, limiting the electrode assembly's dimensions and battery capacity, and pose safety risks due to potential distortion and explosion during thermal testing.
Innovation Solution
A pin with a hollow or solid shape, featuring protrusions and communication holes, is inserted into the center of the electrode assembly to electrically connect the negative plate and the can, eliminating the need for an external anode tab and allowing for a larger electrode assembly diameter, improved assembly process, and enhanced gas discharge.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a rigid nickel strip is used as the anode tab, then the electrical connection between the negative plate and the can is ensured, but the anode tab gets stuck at the opening of the can during assembly, limiting the electrode assembly dimensions and battery capacity
Solution Approach 1:
The invention extracts the problematic rigid nickel strip anode tab from the system and replaces it with a pin-type anode tab that is inserted through the electrode assembly. This extraction eliminates the sticking issue at the can opening while maintaining the electrical connection function, thereby allowing larger electrode assembly dimensions and increased battery capacity
Solution Approach 2:
The invention changes the physical form parameter of the anode tab from a flat rigid nickel strip to a pin structure with diameter of 0.3-1.5 mm. This parameter change transforms the anode tab from a two-dimensional strip that gets stuck at the opening to a three-dimensional pin that can be inserted through the electrode assembly, resolving the contradiction between reliable electrical connection and electrode assembly dimension
2Ease of manufacture
If the electrode assembly outer diameter is reduced to allow margin of 0.2-0.4 mm for insertion, then the assembly process is simplified, but the electrode assembly cannot be enlarged enough to heighten the battery capacity
Solution Approach 1:
By extracting the rigid nickel strip anode tab and replacing it with a pin-type anode tab inserted through the electrode assembly, the invention eliminates the need for margin space at the can opening. This allows the electrode assembly outer diameter to be increased to match the can inner diameter, thereby increasing the active material quantity and battery capacity while maintaining ease of assembly through the pin insertion method
3Reliability
If a rigid nickel strip is used as the anode tab, then the electrical connection is established, but the anode tab is liable to be stuck at the opening portion of the can, incurring an abnormality in the arrangement of the electrode assembly
Solution Approach 1:
The invention changes the anode tab geometry from a flat strip to a pin with diameter 0.3-1.5 mm, and changes its placement method from external attachment to internal insertion through the electrode assembly center. This parameter change ensures proper arrangement of the electrode assembly within the can while maintaining reliable electrical connection through the pin's contact with the negative plate and can
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 design enables a 0.5-1.0% increase in electrode assembly diameter, enhancing battery capacity by 2-5%, prevents assembly issues and distortions, and ensures safe gas discharge, reducing the risk of explosion during high-temperature testing.
Implementation Method 1
A pin is inserted into the electrode assembly, and it contacts the negative plate and the can to electrically interconnect them
Implementation Method 2
protrusions are formed at one side end portion of the pin, and the protrusions are welded to the can
Data Source
AI summary
A secondary battery includes an electrode assembly where a negative plate and a positive plate are arranged by interposing a separator therebetween, and a can mounting the electrode assembly therein. A cap assembly is fitted to the can to tightly seal the can, and is electrically connected to the positive plate. A pin is inserted into the electrode assembly, and it contacts the negative plate and the can to electrically interconnect the negative plate and the can.