Battery Can Sealing Structure to Block Electrolyte Rise
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Solution Overview
Problem
Existing battery sealing methods, such as welding, lead to a decrease in energy density due to the formation of caulking portions and increased volume, and result in welding defects from electrolytic solution mixing into the melting portion, causing capillary phenomena.
Innovation Solution
A battery design featuring a metal can, electrode body, and sealing member with a preventing portion, such as a groove or surface processing, to prevent electrolytic solution rise and mixing into the melting portion, reducing the need for caulking and allowing for a more compact design.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If welding is used to seal the battery can, then sealing reliability is improved, but electrolytic solution mixes into the melting portion causing welding defects
Solution Approach 1:
A preventing portion (protrusion) is formed on the sealing member before the welding process. This protrusion pre-occupies the space between the sealing member and battery can, creating a physical barrier that prevents electrolytic solution from reaching the welding area during the sealing process.
Solution Approach 2:
The preventing portion acts as an intermediary element between the electrolytic solution and the welding area. It serves as a mechanical barrier that blocks the capillary action of the electrolytic solution, allowing welding to proceed without contamination while maintaining sealing effectiveness.
2Reliability
If caulking portions and annular ridges are formed to seal the battery, then sealing effectiveness is improved, but battery volume increases decreasing energy density
Solution Approach 1:
The invention extracts and eliminates the need for annular ridges and extensive caulking portions by using a simplified sealing structure. The sealing member with its preventing portion protrusion provides adequate sealing without requiring the battery can diameter to be reduced inward, thereby removing the volume-increasing feature while maintaining sealing effectiveness.
Solution Approach 2:
The invention changes the sealing approach from mechanical deformation (caulking and ridge formation) to a combination of precision fitting and controlled welding. This parameter change in the sealing mechanism allows for reduced battery volume while maintaining or improving sealing 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
This configuration enhances energy density by preventing electrolytic solution from rising and mixing into the welding area, reducing welding defects and allowing for a more efficient sealing process without the need for annular ridges or caulking, thereby improving the battery's energy-to-volume ratio.
Implementation Method 1
A part of the inner peripheral surface of the opening edge portion and a part of the outer peripheral surface of the sealing member are joined by a melting portion
Implementation Method 2
a preventing portion, which prevents the electrolytic solution from rising toward a position, in which the melting portion is formed, between the inner peripheral surface of the opening edge portion and the outer peripheral surface of the sealing member
Data Source
AI summary
A battery includes a metal battery can that has a tubular portion having an opening edge portion and a bottom portion; an electrode body that is in the battery can; an electrolytic solution that fills the battery can; and a sealing member that has an outer peripheral surface facing an inner peripheral surface of the opening edge portion of the tubular portion and is configured to seal the opening edge portion. A part of the inner peripheral surface of the opening edge portion and a part of the outer peripheral surface of the sealing member are joined by a melting portion, and a preventing portion is on the outer peripheral surface of the sealing member, the preventing portion being configured to prevent the electrolytic solution from rising toward a position, in which the melting portion is formed.