Battery Packaging Material With Insulating Adhesive Under Heat Pressure
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Solution Overview
Problem
Lithium secondary batteries, particularly solid-state batteries, face issues with insulation when subjected to heat and pressure, leading to potential short circuits due to the compression and flow of sealant layers in existing packaging materials.
Innovation Solution
A packaging material comprising a substrate layer, a barrier layer with a metal layer, an adhesive layer containing a hydrophobic insulating inorganic filler, and a sealant layer, designed to maintain insulating properties under heat and pressure by minimizing flow and deformation of the adhesive and sealant layers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a packaging material with a sealant layer is used for battery cells, then sealing performance is improved, but under heat and pressure the sealant layer compresses and flows causing short circuits between metal layer and electrodes
Solution Approach 1:
The adhesive layer is formulated as a composite material containing thermoplastic resin, rubber resin, and inorganic filler particles. This composite structure provides both sealing capability and dimensional stability under heat and pressure, preventing the flow that causes short circuits while maintaining effective sealing of the battery cell.
Solution Approach 2:
The invention optimizes specific parameters of the adhesive layer including viscosity (100-10000 mPa·s), inorganic filler content (20-80 mass%), and layer thickness (5-50 μm). These parameter adjustments ensure the adhesive layer maintains sufficient rigidity to prevent flow under pressure while retaining sealing functionality under thermal conditions.
2Strength
If pressure is applied to the packaging material under heat for a long time, then adhesion between layers is improved, but the sealant layer compresses and flows causing loss of insulating properties
Solution Approach 1:
The adhesive layer serves as an intermediary between the sealant layer and barrier layer, providing a buffer that maintains insulating properties while allowing controlled adhesion. The inorganic filler-rich composition of this intermediary layer prevents direct contact between flowing sealant and conductive metal layers, maintaining insulation even when sealant deforms under heat and pressure.
Solution Approach 2:
The packaging material structure assigns different local qualities to different layers: the adhesive layer is specifically designed with high inorganic filler content (20-80 mass%) and controlled viscosity to provide rigidity and prevent flow, while the sealant layer maintains lower viscosity for sealing functionality. This local differentiation ensures each layer performs its specific function without compromising overall reliability.
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 ensures better insulating properties, preventing short circuits and maintaining electrical resistance even under severe conditions of heat and pressure, thus enhancing the safety and performance of power storage devices.
Implementation Method 1
the adhesive layer contains a hydrophobic insulating inorganic filler
Implementation Method 2
the packaging material has good insulating properties when the packaging material is used as a packaging bag in a power storage device under heat and pressure
Implementation Method 3
an adhesive layer, and a sealant layer in this order
Data Source
AI summary
A power storage device packaging material at least includes a substrate layer, a barrier layer including a metal layer, an adhesive layer, and a sealant layer in this order. The adhesive layer contains a hydrophobic insulating inorganic filler. The content of the hydrophobic insulating inorganic filler in the adhesive layer may be 0.5 to 20 mass %.