Valve Device Positioning in Battery Packaging Material
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Solution Overview
Problem
The existing pouch-type lithium ion secondary battery designs face issues with the valve device breaking due to heat and pressure applied during the sealing process, leading to potential failure in maintaining a gas-tight seal and proper function.
Innovation Solution
A battery design where the valve device is positioned such that its inner end protrudes from the joined edge portion, avoiding direct contact with heat and pressure, and is sandwiched between heat-sealable resin layers for secure bonding, ensuring the valve device remains functional.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the valve device is attached with the inner edge flush with the seal portion, then the valve device can be securely positioned, but the valve device is deformed by heat and pressure during sealing and may break
Solution Approach 1:
The valve device is divided into two functional portions: a first portion (valve mechanism) and a second portion (air passage). This segmentation allows the second portion to be positioned in the joined edge portion for secure attachment while the first portion extends outward to avoid heat and pressure damage during sealing.
Solution Approach 2:
The valve device is configured to extend in the thickness direction of the battery, creating a three-dimensional arrangement where the first portion protrudes from the joined edge portion. This dimensional arrangement separates the vulnerable valve mechanism from the sealing zone, protecting it from heat and pressure while maintaining secure positioning of the air passage portion.
2Reliability
If the valve device is attached through heat sealing, then the valve device is securely bonded to the housing body, but the air passage may be clogged by molten material
Solution Approach 1:
The air passage (second portion) is extracted and positioned within the joined edge portion where it is protected from molten material intrusion. The separation of the air passage from the sealing zone prevents clogging while maintaining secure bonding through the fusion of heat-sealable resin layers.
3Strength
If the valve device is positioned to protrude from the joined edge portion, then the valve device is protected from heat and pressure, but the bonding area is reduced
Solution Approach 1:
The valve device is segmented into two portions with distinct functions: the second portion (air passage) provides bonding area within the joined edge portion, while the first portion (valve mechanism) extends outward to receive protective benefits from reduced heat and pressure exposure.
Solution Approach 2:
Different portions of the valve device have different positioning strategies: the second portion is embedded in the joined edge portion for secure bonding, while the first portion extends outward for protection. This local differentiation optimizes both bonding strength and damage protection.
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 the valve device from breaking during attachment, ensuring proper gas discharge and moisture suppression, with a helium leakage rate between 5.0×10−11 Pa·m3/sec to 5.0×10−6 Pa·m3/sec, and minimal distortion of the housing body after gas discharge, thus maintaining the battery's integrity.
Implementation Method 1
a joined edge portion is formed in the housing body as a result of the first housing portion and the second housing portion being fused along respective peripheral edge portions
Implementation Method 2
a valve mechanism is formed, the valve mechanism being configured to discharge gas generated in the interior space of the housing body to the external space outside the housing body
Data Source
AI summary
A battery includes a battery element, a housing body, and a valve device. The housing body is constituted by at least one laminate and includes an interior space in which the battery element is housed, a first housing portion that covers the interior space from a first side, and a second housing portion that covers the interior space from a second side. The valve device is attached to the housing body and can make interior space of housing body be in communication with an external space. A joined edge portion is formed in housing body as a result of the first and second housing portion being fused along respective peripheral edge portions. The valve device is sandwiched between the first and second housing portion in the joined edge portion, and an inner end of the valve device protrudes from an inner edge of joined edge portion toward the interior space.