Battery Packaging Material Delamination for Pressure Relief
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Solution Overview
Problem
Conventional battery packaging materials fail to maintain a hermetically sealed state during increased pressure or temperature, leading to potential explosions or fires due to rapid gas eruptions, as they are not designed to gently unseal and release pressure.
Innovation Solution
A battery packaging material comprising a laminate structure with a base material layer, a metal layer, and a sealant layer, which delaminates at the interface between the metal and sealant layers to maintain a sealed state until pressure or temperature increases, then gently unseals by generating fine cleavages in the sealant layer to release internal pressure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of stationary object
If a film-shaped laminate packaging material is used to achieve weight reduction and shape diversification, then the packaging material can be easily processed into diversified shapes and achieve thickness reduction, but the packaging material may cause cleavage leading to firing or explosion when pressure or temperature in the battery persistently increases
Solution Approach 1:
The sealant layer is segmented into multiple layers (first sealant layer and second sealant layer) with different melting points. The first sealant layer has a lower melting point and provides initial sealing, while the second sealant layer has a higher melting point and provides secondary sealing. This segmentation allows the packaging to maintain reliability under pressure and temperature increases while still achieving weight reduction compared to metallic packaging.
Solution Approach 2:
The packaging material uses a composite laminate structure consisting of a base material layer, metal layer, adhesive layer, and multi-layer sealant layer. This composite structure combines the lightweight advantage of film materials with the thermal and mechanical stability provided by the metal layer and the controlled unsealing behavior of the multi-layer sealant system, resolving the contradiction between weight reduction and safety under extreme conditions.
2Reliability
If the packaging material is designed to maintain hermetic sealing until pressure or temperature increases to a certain level, then the battery element can be kept hermetically sealed, but the packaging material must be designed to quickly and gently unseal when uncontrollable battery reaction occurs
Solution Approach 1:
The sealant layers are designed with different melting point parameters (first sealant layer: lower melting point, second sealant layer: higher melting point). This parameter differentiation allows the packaging to maintain hermetic sealing under normal operating conditions and then automatically unseal in a controlled manner when temperature increases, without requiring complex mechanical unsealing mechanisms.
Solution Approach 2:
The packaging material's unsealing function is achieved through the inherent thermal properties of the multi-layer sealant system. When temperature increases to a certain level, the sealant layers automatically transition from a sealed state to an unsealed state through melting and delamination, without requiring external activation or complex control mechanisms.
3Reliability
If cleavage induction portion is added to suppress cleavage at heat-sealed part, then breakage can be suppressed when pressure increases, but interlayer delamination or cohesive fracture occurs when strong stress is applied, increasing risk of firing or explosion
Solution Approach 1:
The sealant layer is segmented into multiple layers with different functions. The first sealant layer provides initial sealing and can delaminate from the metal layer to create a pressure relief path. The second sealant layer provides secondary sealing and maintains hermeticity until higher temperatures are reached. This segmentation prevents both cleavage at the heat-sealed part and harmful interlayer delamination by distributing stress across multiple layers.
Solution Approach 2:
The adhesive layer acts as an intermediary between the metal layer and the sealant layers. It provides controlled adhesion that allows the first sealant layer to delaminate from the metal layer under pressure, creating a gentle unsealing path, while preventing harmful cohesive fracture within the adhesive layer itself.
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 solution effectively prevents excessive expansion and uncontrollable reactions by gradually releasing internal pressure, reducing the risk of fires and explosions, ensuring safety by maintaining a sealed state until necessary and then gently unsealing to release gases.
Implementation Method 1
when heating is performed with a battery element hermetically sealed by heat-sealing the battery packaging material, the battery packaging material delaminates at least at a part of the interface between the metal layer and the outside surface of the sealant layer
Implementation Method 2
a laminate including at least a base material layer, a metal layer and a sealant layer in this order
Data Source
AI summary
Presented is battery packaging material which is made of a laminate including, as the essentials, a base material layer, a metal layer and a sealant layer in this order. When a product obtained by packaging a battery element with the packaging material in a hermetically sealed state through heat sealing is heated, the packaging material delaminates at least at a part of the interface between the metal layer and the outside surface of the sealant layer with the hermetically sealed state being kept, and thereafter works so as to make the product unsealed.