Battery Pouch Packaging Structure for Low-Temperature Heat Sealing
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Solution Overview
Problem
Existing secondary battery packaging materials face issues with heat resistance, shape stability, and damage susceptibility due to exposure of metal layers to electrolyte solutions, leading to chemical reactions and potential ignition.
Innovation Solution
A layered structure comprising a heat-resistant resin film outer layer, a metal foil gas barrier layer, and an inner layer made from a thermoplastic polyolefin composition with specific thermal properties, allowing for heat-sealable and stable packaging under low heat-sealing conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a metal foil layer is used as a barrier layer in the packaging material, then moisture and oxygen barrier properties are improved, but the metal layer is susceptible to damage from protruding electrode parts during assembly, leading to exposure and chemical reactions with electrolyte solution
Solution Approach 1:
The patent applies beforehand cushioning by introducing a protective resin layer between the metal foil barrier layer and the electrode assembly. This resin layer acts as a cushion that absorbs mechanical stress from protruding electrode parts during assembly, preventing damage to the metal foil layer before exposure can occur. The resin layer is specifically designed to accommodate electrode protrusions while protecting the underlying metal barrier.
2Weight of stationary object
If the packaging material uses a soft pouch structure to reduce volume and mass, then portability is improved, but the soft structure is more susceptible to mechanical damage and chemical reactions compared to rigid can-type packaging
Solution Approach 1:
The patent employs composite materials by creating a multi-layered packaging structure consisting of resin layers, metal foil barrier layers, and protective resin layers. This composite structure combines the lightweight advantages of resin with the barrier properties of metal foil, while the protective resin layers add mechanical strength and damage resistance. The layered composite provides both weight reduction and enhanced reliability against mechanical and chemical damage.
3Object-affected harmful factors
If heat-sealing temperature is reduced to prevent chemical reactions, then safety is improved, but heat resistance and shape stability of the packaging material deteriorate
Solution Approach 1:
The patent applies local quality by differentiating the thermal properties of different layers in the packaging structure. The sealing layer is designed with lower melting point resin components that enable low-temperature heat sealing, while other layers maintain higher heat resistance for shape stability. This spatial differentiation of thermal properties allows the sealing function to operate at low temperatures without compromising the overall structural integrity at higher temperatures.
4Object-generated harmful factors
If aluminum layer is exposed to electrolyte solution due to packaging damage, then chemical reactions occur generating corrosive gas, but the reaction can be prevented by improving packaging integrity
Solution Approach 1:
The patent uses an intermediary approach by introducing a protective resin layer as a mediator between the metal foil barrier layer and the electrode assembly. This intermediary resin layer prevents direct contact between the metal foil and electrolyte solution, even when electrode parts protrude or minor damage occurs. The mediator absorbs mechanical stress and prevents the chain reaction that would lead to aluminum exposure and corrosive gas generation.
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 packaging material exhibits improved heat resistance, shape stability, and enhanced thermal bonding strength, preventing damage and chemical reactions in high-temperature environments.
Implementation Method 1
the composition constituting the inner layer has at least three endothermic peaks in a temperature-calorie curve when measured by successive self-nucleation and annealing (SSA) using calorimetry (DSC)
Implementation Method 2
the composition constituting the inner layer has at least three endothermic peaks in a temperature-calorie curve when measured by successive self-nucleation and annealing (SSA) using calorimetry (DSC)
Implementation Method 3
a secondary battery packaging material having a layered structure including an outer layer made from a heat-resistant resin film, a metal foil gas barrier layer, and an inner layer made from a composition containing a thermoplastic polyolefin
Implementation Method 4
an aluminum layer, which is a metal foil layer serving as a substrate for maintaining mechanical strength and a barrier layer against moisture and oxygen
Data Source
AI summary
Disclosed is a secondary battery packaging material having a layered structure including an outer layer made from a heat-resistant resin film, a metal foil gas barrier layer, and an inner layer made from a composition containing a thermoplastic polyolefin, the packaging material being heat-sealable in low heat-sealing temperature conditions and exhibiting improved heat resistance and shape stability in a high-temperature environment. The present invention provides a secondary battery packaging material having a layered structure including an outer layer made from a heat-resistant resin film, a metal foil gas barrier layer, and an inner layer made from a composition containing a thermoplastic polyolefin, wherein the composition constituting the inner layer has at least three endothermic peaks in a temperature-calorie curve when measured by successive self-nucleation and annealing (SSA) using differential scanning calorimetry (DSC), wherein the endothermic peaks appear in the range of 90° C. to 180° C.