Integrated Cap Assembly for Secondary Battery Sealing
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Solution Overview
Problem
Conventional cap assemblies for cylindrical secondary batteries are complex to manufacture and have weak component adhesion, leading to increased risks of gas leakage due to the individual insertion and stacking of components, which compromises sealing performance and safety.
Innovation Solution
A cap assembly is designed with a cap-up, a PTC thermistor, a vent, and an insulating plate that prevents contact between the vent and the PTC thermistor, integrated to simplify manufacturing and enhance sealing by forming a unified structure with curling parts that surround the insulating plate and PTC thermistor, ensuring secure adhesion and gas containment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If components of the cap assembly are inserted individually into the insulating gasket, then each component can be positioned separately, but the manufacturing process becomes complex and time-consuming
Solution Approach 1:
The patent combines the cap-up, PTC thermistor, vent, and insulating plate into a single integrated cap assembly structure. This merging of previously separate components into one unified assembly that is inserted as a single unit directly resolves the contradiction by simplifying the manufacturing process (reducing multiple insertion steps to one) while maintaining proper positioning and functionality of all components through their integrated design
2Productivity
If components of the cap assembly are simply stacked, then assembly is straightforward, but the components are weakly adhered and gas leakage risk increases
Solution Approach 1:
The patent implements a nested structure where the vent is positioned within the cap-up, the PTC thermistor is positioned within the vent structure, and the insulating plate is positioned between the vent and cap-up. This nesting arrangement provides straightforward assembly while ensuring strong adhesion and proper sealing, as each component is securely positioned within the structure of the previous component rather than being merely stacked
Solution Approach 2:
The patent enhances the stacked structure by adding dimensional features such as the curling part of the vent that extends outward to cover the insulating plate, and the insulating plate that extends to cover the side surface of the cap-up. This dimensional enhancement transforms a simple stack into a securely adhered assembly with improved sealing performance while maintaining assembly efficiency
3Device complexity
If the vent and PTC thermistor are allowed to contact, then assembly is simpler, but electrical safety is compromised due to potential short circuits
Solution Approach 1:
The patent introduces the insulating plate as an intermediary component positioned between the vent and the PTC thermistor. This insulating plate prevents direct contact and potential short circuits between the conductive vent and the PTC thermistor, thereby ensuring electrical safety. The insulating plate is integrated into the cap assembly structure, so it does not significantly increase assembly complexity while effectively preventing the harmful electrical contact
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 integrated cap assembly simplifies the manufacturing process, enhances sealing performance by preventing gas leakage, and improves electrical safety by ensuring proper functioning of the PTC thermistor at high temperatures, thereby addressing the weaknesses of conventional cap assemblies.
Implementation Method 1
a PTC thermistor disposed under the cap-up
Data Source
AI summary
Provided are a cap assembly for a secondary battery. The cap assembly includes a cap-up, a PTC thermistor disposed under the cap-up, a vent disposed under the PTC thermistor, and an insulating plate disposed between the vent and the cap-up and preventing contact between the vent and the PTC thermistor. Here, the vent includes a curling part bent to cover an external surface of the insulating plate. Further, the secondary battery includes an electrode assembly, a can accommodating the electrode assembly and having an opening, and the cap assembly which seals the can.