Pouch Cell Layer Structure for Penetration-Induced Short Control
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Solution Overview
Problem
Pouch-type secondary batteries face a high risk of explosion when a sharp object penetrates, causing rapid heat generation due to direct contact between the positive and negative electrodes, which existing designs fail to adequately mitigate.
Innovation Solution
A pouch-type secondary battery design featuring a surface protection layer, a sealant layer, a gas barrier layer, and a metal foil layer, where the metal foil layer is connected to the negative electrode and exposed to reduce the risk of explosion by inducing a short circuit before the most dangerous contact occurs, allowing for heat dissipation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the positive electrode is laminated on the outermost side of the electrode assembly, then the structure is simplified and manufacturing is easier, but the risk of large explosion increases because the positive electrode collector and negative electrode active material are the closest to each other
Solution Approach 1:
The pouch is divided into multiple functional layers (surface protection layer, gas barrier layer, sealant layer, and metal foil layer) with different roles. The metal foil layer is specifically positioned to contact the positive electrode first during penetration, segmenting the harmful effect from the most dangerous contact between positive electrode collector and negative electrode active material.
Solution Approach 2:
The metal foil layer is pre-positioned between the positive electrode and the pouch outer surface to create a preliminary protective barrier. When penetration occurs, this layer is designed to contact the positive electrode first, performing a preliminary short circuit that prevents the more dangerous direct contact between positive electrode collector and negative electrode active material.
2Strength
If a sharp object penetrates the secondary battery, then the structural integrity is compromised, but direct contact between positive and negative electrodes causes rapid heat generation and explosion
Solution Approach 1:
The metal foil layer acts as an intermediary element between the penetrating object and the electrode assembly. It is designed to be the first component contacted by the positive electrode during penetration, mediating the energy release through a controlled short circuit that prevents more dangerous thermal runaway scenarios.
Solution Approach 2:
The invention converts the harmful effect of penetration-induced short circuit into a beneficial controlled short circuit between the metal foil layer and positive electrode. This controlled short circuit releases energy in a manageable way that prevents the more dangerous uncontrolled thermal runaway and explosion.
3Reliability
If the positive electrode collector and negative electrode active material contact directly, then a severe short circuit occurs causing large explosion, but existing designs lack effective prevention mechanisms
Solution Approach 1:
The metal foil layer is positioned to create a preliminary anti-action against the harmful direct contact between positive electrode collector and negative electrode active material. By designing the layer structure and material properties, the patent ensures that the metal foil layer contacts the positive electrode first during penetration, counteracting the potential for more dangerous direct electrode contact.
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 reduces heat generation and facilitates heat release, thereby minimizing the risk of explosion when a sharp object penetrates by ensuring the metal foil layer contacts the positive electrode first, thereby reducing the risk of explosion.
Implementation Method 1
the metal foil layer is connected to the positive electrode first, thereby reducing the risk of explosion
Implementation Method 2
reduces heat generation and facilitates heat release
Data Source
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AI summary
To solve the above problem, a pouch-type secondary battery according to an embodiment of the present invention includes: an electrode assembly in which a positive electrode, a separator, and a negative electrode are laminated; and a pouch configured to accommodate the electrode assembly, wherein the pouch includes: a surface protection layer made of a first polymer and formed at an outermost layer; a sealant layer made of a second polymer and formed at an innermost layer; a gas barrier layer made of a first metal and laminated between the surface protection layer and the sealant layer; and a metal foil layer made of a second metal, laminated between the surface protection layer and the sealant layer, and connected to the negative electrode of the electrode assembly.