Secondary Battery Thermal Contractible Protection Layer
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Solution Overview
Problem
Secondary batteries experience swelling of the electrode assembly during charging and discharging, leading to deformation and product defects due to heat generation and interface expansion.
Innovation Solution
A secondary battery design incorporating a case with a thermal contractible protection layer made of insulative materials like nylon or polypropylene, which contracts to suppress swelling and maintain insulation, preventing deformation and short circuits while improving sealability and stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the electrode assembly is accommodated in a conventional case without thermal contractible protection layer, then the battery structure is simple, but the electrode assembly swells and deforms during charging/discharging causing product defects
Solution Approach 1:
The case is constructed as a composite structure with multiple layers including a metal layer, an outer adhesion layer, and a thermal contractible protection layer. This composite material approach provides both structural integrity and the specific functional property of thermal contraction to suppress electrode assembly swelling during charging and discharging cycles.
Solution Approach 2:
The thermal contractible protection layer changes its physical parameters (contracts) in response to temperature changes during charging and discharging. This parameter change allows the layer to dynamically adjust and apply compressive force on the electrode assembly, preventing swelling without requiring complex active control mechanisms.
2Shape
If a thermal contractible protection layer is added to the case, then electrode assembly swelling is suppressed, but the case structure becomes more complex
Solution Approach 1:
The thermal contractible protection layer is implemented as a thin film structure that can conform to the electrode assembly shape and provide uniform compressive force. This thin film approach maintains shape control effectiveness while minimizing the added structural complexity and volume compared to rigid alternative solutions.
Solution Approach 2:
The case uses a composite structure where the thermal contractible protection layer is integrated with metal and adhesion layers. This composite approach distributes the functional requirements across different material layers, with each layer contributing specific properties, thereby managing overall structural complexity while achieving the shape control function.
3Reliability
If the thermal contractible protection layer is made of insulative material, then short circuit prevention is improved, but the thermal contraction function may be reduced
Solution Approach 1:
The case structure uses a composite material system where the thermal contractible protection layer provides both the insulative property to prevent short circuits and the thermal contraction capability through careful material selection. The composite structure allows these seemingly conflicting properties to coexist by leveraging the specific characteristics of different materials in different layers.
Solution Approach 2:
The thermal contractible protection layer undergoes parameter changes (contraction) in response to temperature variations during battery operation. This thermally-driven parameter change enables the layer to maintain both its insulative function and its shape control function, as the contraction itself is triggered by the temperature changes that occur during normal charging and discharging cycles.
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
Effectively prevents electrode assembly deformation and secondary battery expansion, enhancing safety and marketability by absorbing heat and maintaining insulation properties, thus reducing the risk of short circuits and prolonging battery lifespan.
Implementation Method 1
the case comprises a thermal contractible protection layer that is contracted by heat
Implementation Method 2
enhancing safety and marketability by absorbing heat and maintaining insulation properties
Data Source
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AI summary
The present invention relates to a secondary battery comprising: an electrode assembly; and a case in which the electrode assembly is accommodated, wherein the case comprises a thermal contractible protection layer that is contracted by heat.