Battery Pouch Venting Structure for Gas Release and Moisture Blocking
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Solution Overview
Problem
Secondary batteries face issues with gas pressure buildup leading to pouch venting, explosion, or ignition, and moisture ingress, which deteriorates performance and safety.
Innovation Solution
Incorporating a gas discharge part between the electrode lead and sealing part of the pouch, comprising a gas transmitting film and moisture absorbing material to discharge gases externally while blocking moisture ingress.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the pouch is sealed tightly to prevent moisture ingress, then moisture blocking is improved, but gas discharge capability deteriorates
Solution Approach 1:
The sealing part is segmented into multiple functional layers: a gas discharge part with gas permeability for venting internal pressure, and a moisture blocking part with moisture blocking capability. This segmentation allows the sealing structure to simultaneously achieve both gas discharge and moisture prevention functions that are contradictory in a homogeneous material.
Solution Approach 2:
The sealing part is designed as a multi-functional component that performs both sealing (moisture blocking) and gas discharge functions. The gas discharge part and moisture blocking part work together to create a universal sealing structure that addresses both safety (gas venting) and performance (moisture prevention) requirements.
2Reliability
If the pouch is designed with gas discharge capability to prevent explosion, then safety is improved, but moisture ingress risk increases
Solution Approach 1:
Different regions of the sealing part are assigned different functional properties: the gas discharge part has high gas permeability for safety venting, while the moisture blocking part has low moisture permeability for preventing degradation. This local differentiation of material properties resolves the contradiction between safety and moisture protection.
Solution Approach 2:
The sealing part acts as an intermediary structure between the internal battery environment and external atmosphere. It selectively mediates gas and moisture transmission through its dual-function design, allowing harmful internal gas to escape while blocking external moisture from entering.
3Reliability
If a gas discharge part is added between electrode lead and sealing part, then safety is improved, but device complexity increases
Solution Approach 1:
The gas discharge part is merged with the sealing part to form an integrated multi-functional sealing structure. By combining the gas discharge function and moisture blocking function into a single unified component rather than separate parts, the design achieves safety improvement while minimizing the increase in device complexity.
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
Enhances safety by stabilizing gas discharge and preventing moisture entry, thereby preventing pouch venting and improving battery performance.
Implementation Method 1
a gas transmitting film having air permeability
Implementation Method 2
a moisture absorbing material that absorbs moisture passing through the gas transmitting film
Data Source
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AI summary
A secondary battery according to the present invention comprises: an electrode assembly to which an electrode lead is coupled; a pouch comprising an accommodation part configured to accommodate the electrode assembly in a state, in which a front end of the electrode lead is withdrawn to the outside, and a sealing part formed along a circumference of the accommodation part to seal the accommodation part; and a gas discharge part provided in the pouch to discharge a gas from the inside to the outside of the pouch and block an inflow of moisture from the outside to the inside of the pouch, wherein the gas discharge part comprises: a gas transmitting film having air permeability, by which the gas inside the accommodation part is discharged to the outside; and a moisture absorbing material that absorbs the passing through the gas transmitting film to block the inflow of the moisture from the outside to the inside of the pouch.