Battery Case Vent Structure to Prevent Safety Valve Blockage
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Solution Overview
Problem
Existing power storage devices face issues with the safety valve being blocked by broken pieces of the electrode body during nail penetration tests, leading to hindered gas release, and existing methods for forming metal protrusions to prevent this are costly, prone to deformation, or have low productivity.
Innovation Solution
A power storage device with a metal case member featuring a resin protrusion joined to a nano-level roughened case inner surface, utilizing nanocolumns to enhance joining strength and prevent electrode body pieces from blocking the safety valve.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a metal protrusion is formed by press forming the case member to prevent electrode body pieces from blocking the safety valve, then the safety valve protection function is improved, but the case member is easily distorted and deformed during pressing, causing leaks when the case is sealed
Solution Approach 1:
The protrusion is divided into two separate components: a metal protrusion formed on the case member and a resin protrusion formed separately. These two protrusions are then combined through injection molding to create a composite structure that provides both mechanical strength and protection without requiring high-pressure pressing of the entire case member.
Solution Approach 2:
The invention uses a composite structure combining metal and resin materials. The metal protrusion provides structural support and integration with the case member, while the resin protrusion provides the blocking prevention function. This composite approach allows each material to contribute its strengths without the drawbacks of using either material alone.
2Reliability
If a metal protrusion is welded to the case member to prevent electrode body pieces from blocking the safety valve, then the safety valve protection function is improved, but the case member is easily deformed during welding and costs increase
Solution Approach 1:
The metal protrusion and resin protrusion are merged into a single integrated component through injection molding. The resin is injected around the metal protrusion, creating a unified structure that combines both materials. This eliminates the need for separate welding operations while providing the same safety valve protection function.
3Reliability
If the case member with metal protrusion is formed by casting to prevent electrode body pieces from blocking the safety valve, then the safety valve protection function is improved, but productivity decreases and costs increase
Solution Approach 1:
The metal protrusion is pre-formed on the case member before the resin protrusion is injected. This preliminary formation of the metal protrusion allows for efficient production without requiring complex casting operations. The pre-formed metal protrusion serves as a nucleus for the subsequent resin injection process.
4Reliability
If the protrusion height is increased to improve blockage prevention, then the safety valve protection function is improved, but the metal protrusion cannot be formed in a desired shape by press forming and case member distortion increases
Solution Approach 1:
The invention changes the material parameter from metal alone to a composite of metal and resin. This allows the protrusion to achieve greater height and more complex shapes without the limitations of press forming metal. The resin material can be molded into desired shapes that would be difficult or impossible to achieve with metal press forming alone.
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 resin protrusion effectively prevents the safety valve from being blocked, ensuring proper gas release and increased joining strength while reducing costs and deformation risks.
Implementation Method 1
nanocolumns formed by joining particles derived from the metal that forms the case member together like strings of beads into the form of columns and having a height of 50 nm or greater stand numerously on the valve periphery roughened portion, and the blockage preventing resin protrusion is joined to the valve periphery roughened portion such that a resin material that forms the blockage preventing resin protrusion fills gaps between the nanocolumns standing numerously
Data Source
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AI summary
A power storage device (1) includes a safety valve (30) in a case member (21) made of metal. The case member (21) has a valve periphery roughened portion (24) around the safety valve on a case inner surface (23). The power storage device (1) includes a blockage preventing resin protrusion (40) that is a protrusion made of resin and protruding to the inside (EH). The blockage preventing resin protrusion (40) is joined to the valve periphery roughened portion (24) and reduces the possibility of a piece of the electrode body (50) blocking the safety valve (30). Nanocolumns (26) stand numerously on the valve periphery roughened portion (24), and the blockage preventing resin protrusion (40) is joined to the valve periphery roughened portion (24) such that a resin material (45) fills gaps between the nanocolumns (26) standing numerously.