Battery Safety Valve Assembly for Stable Pressure Relief
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Solution Overview
Problem
Existing power storage devices face challenges in forming a safety valve portion of a desired shape and thickness due to the thickness and material of the case member, especially when the case member is made of metal and increases in size.
Innovation Solution
A power storage device with a separate safety valve member made of metal and a valve fixing resin member made of resin, where the resin member hermetically joins the safety valve member to the case member, allowing for independent formation of the safety valve member without being affected by the case member's thickness and material.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the safety valve portion is formed integrally with the case member by pressing, then the structure is simplified, but it becomes difficult to properly form the safety valve portion in a desired shape when the case member thickness increases
Solution Approach 1:
The safety valve member is separated from the case member as an independent component. The safety valve member includes a valve body with a through-hole, and the thickness of the valve body can be independently controlled regardless of the case member thickness. This segmentation allows the safety valve portion to be properly formed even when the case member is thick.
Solution Approach 2:
The safety valve function is extracted from the case member and implemented as a separate safety valve member. This extracted component can be manufactured with precise thickness and shape requirements independent of the case member's thickness, solving the problem of forming difficulty in thick case members.
2Strength
If the case member thickness is increased to accommodate larger battery size, then the structural strength is improved, but the safety valve portion cannot be formed with suitable thickness
Solution Approach 1:
By separating the safety valve member from the case member, the thickness of the safety valve portion can be independently controlled. The case member maintains its required thickness for structural strength, while the safety valve member has its own optimized thickness for proper valve formation, resolving the conflict between strength and manufacturability.
Solution Approach 2:
The safety valve member is designed with local thickness optimization. The valve body has a specific thickness that is suitable for press working and forming the safety valve portion, while the case member maintains its overall thickness for structural support. This local quality differentiation allows both requirements to be satisfied simultaneously.
3Manufacturing precision
If the safety valve member is formed separately from the case member, then the desired shape can be achieved, but additional joining process is required
Solution Approach 1:
A resin member is introduced as an intermediary between the safety valve member and the case member. The resin member fills the space between the through-hole of the safety valve member and the case member, providing hermetic sealing and mechanical bonding. This intermediary component facilitates the joining process while maintaining the independence of the safety valve member for precise shape formation.
4Ease of manufacture
If the case member is distorted during case formation, then the case can be formed, but the safety valve portion may be affected adversely
Solution Approach 1:
The safety valve member is segmented from the case member, allowing it to be manufactured separately with precise dimensional control. This separation isolates the safety valve portion from distortion effects during case formation, ensuring that valve opening pressure remains stable even when the case undergoes forming distortions.
Solution Approach 2:
The resin member acts as a cushioning element between the safety valve member and the case member. During case formation, any distortion or stress is absorbed by the resin member rather than being transmitted to the safety valve member, protecting the valve opening pressure from adverse effects before they can occur.
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 enables easy and accurate formation of the safety valve portion, maintaining stable valve opening pressure and reducing distortion, while also providing thermal relief through the resin's softening or melting, enhancing seal performance and joining strength.
Implementation Method 1
a valve fixing resin member comprising resin and encircling the safety valve member. The valve fixing resin member is interposed between a hole surrounding portion of the case member surrounding the valve hole and a peripheral portion of the safety valve member to be hermetically joined to the hole surrounding portion and the peripheral portion over the entire circumferences and fix the safety valve member to the case member
Implementation Method 2
the safety valve member and the valve fixing resin member may constitute a safety valve of a thermal relief type configured to open when the resin material softens or melts due to a temperature rise of the valve fixing resin member
Data Source
AI summary
A power storage device includes a case having a case member made of metal and including a valve hole, a safety valve member made of metal and including a safety valve portion of a pressure relief type which fractures and opens when the internal pressure of the case exceeds a valve opening pressure, and a valve fixing resin member made of resin and encircling the safety valve member. The valve fixing resin member is interposed between a hole surrounding portion of the case member surrounding the valve hole and a peripheral portion of the safety valve member to be hermetically joined to these portions over the entire circumferences and fix the safety valve member to the case member.