Pouch Battery Cell Sealing Layout for Directed Thermal Venting
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Solution Overview
Problem
Existing battery cells face challenges in managing the venting direction of internal gas during a battery fire, which can lead to damage and safety issues due to uneven pressure distribution and sealing weaknesses.
Innovation Solution
The battery cell design incorporates a pouch unit with distinct sealing portions, including polymerized and welded pouch sheets, to create different coupling forces along the edges. This configuration allows for controlled venting of gas generated inside the battery cell during a fire.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a single sealing portion is used along the perimeter of the battery cell body, then the manufacturing process is simple, but the venting direction of gas during thermal runaway cannot be controlled and pressure distribution is uneven
Solution Approach 1:
The sealing structure is divided into multiple segments: a first sealing portion formed by polymerization of resin at a first edge, and a second sealing portion formed by welding of metal layers at a second edge. This segmentation allows different sealing mechanisms to be applied at different locations, enabling controlled venting direction while maintaining manufacturing feasibility.
Solution Approach 2:
Different sealing methods are applied to different edges of the battery cell based on local requirements. The first edge uses polymerization-based sealing while the second edge uses welding-based sealing, creating localized sealing characteristics that control gas venting direction during thermal runaway events.
2Ease of manufacture
If polymerization sealing is used at all edges, then the sealing is uniform and simple to manufacture, but the coupling force is insufficient at edges requiring stronger attachment
Solution Approach 1:
The patent applies different sealing methods to different edges based on local strength requirements. Edges requiring stronger coupling force use welding of metal layers, while other edges use polymerization sealing, creating localized strength variations that match functional requirements.
Solution Approach 2:
The sealing structure combines different material systems: polymer resin for sealing and metal layers for welding. This composite approach allows the structure to exhibit both the sealing properties of polymers and the high-strength bonding capabilities of metals at different locations.
3Device complexity
If the metal layer melting point is close to the inner layer melting point, then the sealing structure is simple, but the controlled venting function cannot be achieved during thermal runaway
Solution Approach 1:
The patent changes the thermal parameter (melting point) of the sealing materials by selecting metal layers with melting points significantly higher than the inner layer. This parameter differentiation enables the inner layer to fail first during thermal runaway, creating a controlled venting path while the metal layer sealing remains intact.
Solution Approach 2:
The sealing structure is pre-designed with differential melting points so that during thermal runaway, the inner layer melts and opens a venting path before the metal layer sealing fails. This preliminary design ensures controlled gas release direction without requiring active control mechanisms.
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 effectively sets the venting direction of gas, reducing the risk of damage to the battery cell and enhancing safety by ensuring controlled release of pressure during a thermal runaway event.
Implementation Method 1
The weak portion of the pouch seal may be a sealing portion in which pouches facing each other are in contact with and coupled to each other. The pouches facing each other are coupled by polymerizing a resin
Implementation Method 2
a pair of second pouch sealing portions extending from another part of the pair of first pouch sealing portions and having the metal layers that face each other and are coupled
Data Source
Figure 1a
Figure 1b
Figure 2
AI summary
A battery cell and a method of manufacturing the same are disclosed. The battery cell includes an electrode assembly (100) and a pouch unit (300) wrapping and accommodating the electrode assembly (100), and the pouch unit (300) includes an inner layer, an outer layer, and a metal layer disposed between the inner layer and the outer layer. The battery cell may comprise a battery cell body (11) including an accommodation portion (310) of the pouch unit (300) accommodating the electrode assembly (100) and the electrode assembly (100); an electrode lead (200) protruding from the battery cell body (11); a first battery cell sealing portion (16a) formed along a portion of a perimeter of the battery cell body (11), the first battery cell sealing portion (16a) including a part of a pair of first pouch sealing portions (321) extending from the accommodation portion (310) and having the inner layers that face each other and are coupled with the electrode lead (200) interposed therebetween; and a second battery cell sealing portion (16b) formed along another portion of the perimeter of the battery cell body (11), the second battery cell sealing portion (16b) including another part of the pair of first pouch sealing portions (321) and a pair of second pouch sealing portions (322) extending from the another part of the pair of first pouch sealing portions (321) and having the metal layers that face each other and are coupled.