Pouch Battery Cell Seal Segmentation for Directed Gas Venting
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Solution Overview
Problem
Pouch battery cells experience pressure buildup due to gas generation during charge/discharge cycles and harsh environments, leading to seal damage and uncontrolled venting of high-temperature gas during thermal runaway, necessitating controlled venting direction.
Innovation Solution
A battery cell design with distinct sealing portions formed by polymerization and welding, utilizing layers of different materials with varying melting points to control venting direction during a fire, including an inner layer, outer layer, and metal layer with specific coupling mechanisms.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single sealing portion is used for the pouch battery cell, then the manufacturing process is simple, but the venting direction of gas during thermal runaway cannot be controlled
Solution Approach 1:
The sealing portion is divided into multiple segments: a first sealing portion with a first breaking strength and a second sealing portion with a second breaking strength. This segmentation allows different portions to fail at different strengths, thereby controlling the venting direction of gas during thermal runaway to occur through the first sealing portion while the second sealing portion remains intact.
Solution Approach 2:
Different portions of the sealing structure are assigned different properties: the first sealing portion is designed with lower breaking strength to serve as the primary venting path, while the second sealing portion maintains higher breaking strength to preserve structural integrity. This local differentiation enables controlled venting while maintaining overall reliability.
2Strength
If the pouch seal is made strong to withstand pressure, then the cell maintains structural integrity, but the seal may not break in a controlled manner during thermal runaway
Solution Approach 1:
The sealing portion is divided into multiple segments: a first sealing portion with a first breaking strength and a second sealing portion with a second breaking strength. This segmentation allows different portions to fail at different strengths, thereby controlling the venting direction of gas during thermal runaway to occur through the first sealing portion while the second sealing portion remains intact.
Solution Approach 2:
The breaking strength parameter of different sealing portions is deliberately differentiated. The first sealing portion is designed with a lower breaking strength parameter to fail first under pressure, while the second sealing portion maintains a higher breaking strength parameter. This parameter differentiation ensures controlled venting while maintaining overall structural integrity.
3Ease of manufacture
If all sealing portions are made with the same material properties, then the manufacturing process is simple, but different edges require different coupling forces
Solution Approach 1:
Different portions of the sealing structure are assigned different properties: the first sealing portion is designed with lower breaking strength to serve as the primary venting path, while the second sealing portion maintains higher breaking strength to preserve structural integrity. This local differentiation enables controlled venting while maintaining 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 design provides controlled venting of gas during a battery fire, ensuring safety by setting the venting direction and preventing damage, thus enhancing the safety of battery modules.
Implementation Method 1
The pouches facing each other are coupled by polymerizing a resin, and thus the pouch can be sealed.
Implementation Method 2
the metal layers of the pair of second pouch sealing portions face each other and are coupled
Data Source
AI summary
A battery cell and a method of manufacturing the same are disclosed. an electrode assembly and a pouch unit wrapping and accommodating the electrode assembly, the pouch unit including an inner layer, an outer layer, and a metal layer disposed between the inner layer and the outer layer, the battery cell comprising: a battery cell body; an electrode lead; a first battery cell sealing portion; and a second battery cell sealing portion. The inner layers of the part of the pair of first pouch sealing portions face each other and are coupled with the electrode lead interposed therebetween, and the metal layers of the pair of second pouch sealing portions face each other and are coupled.