Swelling Tape for Battery Gap Filling and Assembly Fixation
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Solution Overview
Problem
Batteries face performance degradation due to gaps between the electrode assembly and the cylindrical can, leading to increased internal resistance and potential damage from external vibrations, as the electrode assembly is not securely fixed in place.
Innovation Solution
A swelling tape with a polyurethane film and pressure-sensitive adhesive layer is used to fill the gap between the electrode assembly and the can, comprising a substrate film with a controlled weight ratio of polyisocyanate and chain extender to provide excellent supporting strength and resistance, allowing the tape to form a three-dimensional shape and securely fix the assembly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a gap filler is used to fill the gap between the electrode assembly and the can, then the electrode assembly is securely fixed in place, but the gap filler may extend or deform when the tape is unwound, compromising fixing reliability
Solution Approach 1:
The patent changes the physical and chemical parameters of the polyurethane film by controlling the weight ratio of hard region components (polyisocyanate compound and chain extender) to soft region components (polyol compound). By adjusting this ratio to specific ranges, the film achieves optimal balance between hardness for maintaining shape and flexibility for gap filling, preventing extension and deformation during unwinding while ensuring reliable fixation.
Solution Approach 2:
The patent creates a composite polyurethane structure with distinct hard regions and soft regions. The hard regions, formed by polyisocyanate compound and chain extender, provide structural support and resistance to deformation. The soft regions, formed by polyol compound, provide flexibility and adaptability for gap filling. This composite structure resolves the contradiction between maintaining film shape and enabling gap filling.
2Reliability
If the polyurethane film has high hardness to prevent extension and deformation, then fixing reliability is improved, but the supporting strength and resistance may be insufficient for effective gap filling
Solution Approach 1:
The patent optimizes the hardness parameter of the polyurethane film by controlling the weight ratio of hard region components (polyisocyanate compound and chain extender) to soft region components (polyol compound) within specific ranges. This parameter adjustment ensures the film has sufficient hardness to prevent extension and deformation during unwinding, while maintaining adequate supporting strength and resistance for effective gap filling and electrode assembly fixation.
Solution Approach 2:
The patent employs a composite polyurethane material structure with hard regions providing structural support and resistance to deformation, and soft regions providing flexibility and supporting strength. This composite approach allows the film to simultaneously achieve sufficient hardness for preventing extension and adequate softness for maintaining supporting strength during gap filling operations.
3Reliability
If the weight ratio of polyisocyanate compound and chain extender is increased to form more hard regions, then resistance to extension and deformation is improved, but the film may become too rigid for effective gap filling
Solution Approach 1:
The patent precisely controls the weight ratio parameters of polyisocyanate compound and chain extender relative to polyol compound within specific ranges. This parameter optimization ensures the formation of an appropriate amount of hard regions that provide resistance to extension and deformation, while maintaining sufficient soft region content to enable the film to adapt to and effectively fill gaps of varying sizes and shapes.
Solution Approach 2:
The patent creates local quality differentiation within the polyurethane film by forming distinct hard regions and soft regions. The hard regions, formed by polyisocyanate compound and chain extender, provide localized resistance to extension and deformation. The soft regions, formed by polyol compound, provide localized flexibility and adaptability for gap filling. This local quality distribution resolves the contradiction between resistance to deformation and adaptability.
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 swelling tape effectively fills the gap and prevents movement of the electrode assembly, enhancing battery performance by maintaining the assembly's position and reducing internal resistance, as demonstrated by improved vibration and impact resistance tests.
Implementation Method 1
The polyurethane includes polymer compounds bound by a urethane bond. The polyurethane has a large molecular weight, and is prepared by forming a urethane (-NHCOO-) group by bonding an alcohol (-OH) group located at the end of polyol to an isocyanate (-NCO) group of a polyisocyanate compound
Implementation Method 2
A swelling tape for filling a gap and a method of filling a gap in a battery. The tape includes a substrate film and a pressure-sensitive adhesive layer formed on one surface of the substrate film
Data Source
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Figure 3
AI summary
The present invention relates to swelling tape for filling a gap and its use. The swelling tape is, for example, applied between gaps in which a fluid is present, thereby being deformed into a three-dimensional shape to fill the gap and fix an object separated by gaps as needed.