Insulating Case Deformation Holes for Secondary Battery Safety
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Secondary batteries face reliability issues due to internal short circuits, overcharge, and overdischarge, leading to temperature rises and potential explosions, which damage the electrode assembly, insulating case, and cap assembly, causing electrolyte leakage and loss of function.
Innovation Solution
A secondary battery design featuring an insulating case made of polyphenylene sulfide with deformation holes and protrusions that provide mechanical stability and easy coupling with the can, ensuring excellent electric insulation and flame-retardation, while maintaining the structural integrity and safety of the battery.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional insulating cases are used, then the battery can be assembled, but the insulating case lacks mechanical stability and deforms under thermal stress, leading to poor sealing and electrolyte leakage
Solution Approach 1:
The insulating case is made from a composite material comprising polyphenylene sulfide (PPS) and polytetrafluoroethylene (PTFE), which combines the high heat resistance and mechanical strength of PPS with the chemical inertness and low friction of PTFE. This composite structure provides superior mechanical stability and thermal resistance compared to conventional single-material insulating cases, preventing deformation under thermal stress and ensuring reliable sealing.
Solution Approach 2:
The invention changes the material parameters of the insulating case by selecting a specific composite material formulation with optimized proportions of PPS and PTFE. This material parameter change results in enhanced mechanical properties, including higher modulus of elasticity and improved dimensional stability at elevated temperatures, directly addressing the deformation issue.
2Strength
If high-hardness materials are used for the insulating case, then mechanical strength is improved, but the insulating case becomes difficult to couple with the can and may cause damage during assembly
Solution Approach 1:
The insulating case incorporates a thin film structure of PTFE coating on the PPS substrate. This thin film provides flexibility and elasticity that allows the rigid high-hardness composite material to be easily coupled with the can during assembly without causing damage, while maintaining its mechanical strength for structural support.
Solution Approach 2:
The insulating case has different local properties: the PPS core provides high strength and rigidity where structural support is needed, while the PTFE surface layer provides low friction and flexibility where contact with the can occurs during assembly. This local differentiation of material properties resolves the contradiction between strength and ease of assembly.
3Ease of manufacture
If the insulating case is made with simple structure, then manufacturing is easier, but it lacks the mechanical stability and coupling capability with the can
Solution Approach 1:
The insulating case is segmented into two functional layers: an inner PPS structural layer that provides mechanical stability and shape retention, and an outer PTFE functional layer that provides coupling capability and protects against deformation. This segmentation allows each layer to be optimized for its specific function while maintaining overall manufacturing simplicity through co-molding or coating processes.
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 enhances the mechanical stability and safety of the secondary battery by preventing deformation and electrolyte leakage, maintaining insulation, and ensuring reliable operation even under high temperatures, thus improving the battery's reliability and safety.
Implementation Method 1
an insulating case interposed between the cap assembly and the electrode assembly... excellent electric insulation
Implementation Method 2
a sealing material with low thermal deformation... excellent flame-retardation... low occurrence, such as a short circuit, overcharge, and overdischarge, continues for a certain time, the temperature of the secondary battery significantly rises
Implementation Method 3
a first protrusion formed on the first side surface... The first protrusion has a first contact portion that contacts an inner surface of the can
Data Source
AI summary
The present invention relates to a secondary battery including an insulating case interposed between the cap assembly and the electrode assembly. The insulating case is made of a sealing material with low thermal deformation, excellent flame-retardation, and excellent electric insulation so as to be able to enhance the reliability of the secondary battery. The secondary battery of the present invention includes a can having an open top, an electrode assembly disposed inside the can and generating electricity, a cap assembly sealing the open top of the can, and an insulating case interposed between the cap assembly and the electrode assembly. The insulating case includes a base having an upper surface and a side surface, and a protrusion formed on the side surface. The upper surface has a deformation hole. The deformation hole and the protrusion are arranged in a manner that a line connecting the center of the deformation hole to the protrusion is substantially perpendicular to the side surface.