Secondary Battery Cap Assembly Laser Fusion
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Solution Overview
Problem
Lithium ion secondary batteries face safety issues due to electrolyte leakage between the safety vent and insulator, and the insulator and cap-down, which compromises the battery's integrity.
Innovation Solution
The implementation of laser patterns on the safety vent and cap-down, specifically wedge-shaped grooves with a 60-degree angle and 0.05 mm depth, enhances the coupling forces between these components by thermal fusion of the insulator, reducing electrolyte penetration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional cap assembly structure is used without laser patterns, then manufacturing is simpler, but coupling force between safety vent and insulator is insufficient causing electrolyte leakage
Solution Approach 1:
The patent replaces mechanical coupling methods with laser-based thermal fusion. Laser patterns are formed on the safety vent and cap-down surfaces, and the insulator is thermally fused to these laser patterns through laser heating, achieving strong coupling without mechanical fasteners or adhesives.
Solution Approach 2:
The patent changes the physical state and properties of materials through laser heating. The laser patterns alter the surface properties of the safety vent and cap-down, and the thermal fusion process changes the insulator from a separate component to a bonded structure, achieving improved coupling strength.
2Reliability
If conventional cap assembly structure is used without laser patterns, then manufacturing is simpler, but electrolyte leakage occurs reducing battery safety
Solution Approach 1:
The patent replaces mechanical coupling methods with laser-based thermal fusion. Laser patterns are formed on the safety vent and cap-down surfaces, and the insulator is thermally fused to these laser patterns through laser heating, achieving strong coupling without mechanical fasteners or adhesives.
Solution Approach 2:
The patent changes the physical state and properties of materials through laser heating. The laser patterns alter the surface properties of the safety vent and cap-down, and the thermal fusion process changes the insulator from a separate component to a bonded structure, achieving improved coupling strength.
3Strength
If laser patterns are formed on safety vent and cap-down, then coupling force is improved, but manufacturing process becomes more complex
Solution Approach 1:
The patent replaces mechanical coupling methods with laser-based thermal fusion. Laser patterns are formed on the safety vent and cap-down surfaces, and the insulator is thermally fused to these laser patterns through laser heating, achieving strong coupling without mechanical fasteners or adhesives.
Solution Approach 2:
The patent changes the physical state and properties of materials through laser heating. The laser patterns alter the surface properties of the safety vent and cap-down, and the thermal fusion process changes the insulator from a separate component to a bonded structure, achieving improved coupling strength.
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 significantly improves the safety of the battery by preventing electrolyte leakage and maintaining high tensile strength even after prolonged electrolyte immersion, ensuring the battery's structural integrity.
Implementation Method 1
Laser patterns formed by using a laser beam are on a bottom surface of the safety vent and a top surface of the cap-down. The safety vent and the cap-down may each include oxide coatings, and the oxide coatings may not be present at portions of the safety vent and the cap-down at where the laser patterns are located.
Implementation Method 2
The insulator may be fused to the safety vent and the cap-down by thermal fusion, and protrusions may be on a surface of the insulator corresponding to the grooves of the laser patterns.
Data Source
AI summary
A secondary battery includes an electrode assembly, a case accommodating the electrode assembly, and a cap assembly coupled to a top portion of the case. The cap assembly includes a cap-up, a safety vent under the cap-up, a cap-down under the safety vent, an insulator between the safety vent and the cap-down, and a sub-plate on a bottom surface of the cap-down. Laser patterns formed by using a laser beam are on a bottom surface of the safety vent and a top surface of the cap-down.