Battery Case Stepped Corner Forming for Stable Sealing Plate Fit
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Solution Overview
Problem
Existing methods for forming stepped portions in battery cases result in unstable sealing plate installation due to material deformation and resistance issues, leading to potential rupture or misalignment, which affects the stability and alignment of the sealing plate.
Innovation Solution
A battery case design with a depressed corner and mounting surface configuration, where the depressed corner is formed by depressing the inner wall surface to a predetermined depth, followed by forming a stepped portion with controlled plastic flow to ensure the sealing plate is accurately positioned and securely attached.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the ironing method is used to form the stepped portion by flowing material plastically along a punch, then the stepped portion can be formed, but the material resistance causes wall portion rupture between the die and the stepped portion, requiring reduced processing speed
Solution Approach 1:
The punch forms a rounded corner portion first, which then serves as a stress distribution feature during subsequent material flowing. This preliminary shaping prevents concentration of forces that would cause rupture, allowing higher processing speeds without compromising wall integrity
Solution Approach 2:
The punch tip is designed with a predetermined curvature radius to create a rounded corner portion. This curvature distributes stress evenly during the ironing process, preventing material rupture while enabling faster processing speeds compared to sharp-cornered approaches
2Productivity
If the stepped portion is formed mildly to increase processing speed, then the processing speed increases, but the mounting surface cannot be formed parallel to the opening edge, causing sealing plate misalignment
Solution Approach 1:
The forming process is divided into two distinct stages: first forming the rounded corner portion, then forming the stepped portion with the mounting surface. This segmentation allows each feature to be optimized independently - the rounded corner for stress distribution and the stepped portion for precise parallelism
Solution Approach 2:
The rounded corner portion is formed as a preliminary feature before the stepped portion. This preliminary action creates a stress-distributing geometry that enables subsequent high-speed forming of the mounting surface without compromising its parallelism to the opening edge
3Manufacturing precision
If the curvature radius of the punch tip is reduced to reduce the rounded corner radius, then the rounded corner interference with sealing plate edges is reduced, but the side wall between the punch and die would be ruptured
Solution Approach 1:
The punch tip maintains a predetermined curvature radius that creates a rounded corner portion. This curvature is optimized to be large enough to prevent side wall rupture during forming, yet the rounded corner is positioned and sized to not interfere with rectangular sealing plate edges during installation
4Ease of manufacture
If the clearance between the push punch and die is too wide to form the stepped portion by pushing, then the processing is easier, but the stepped portion becomes inclined, causing unstable sealing plate support
Solution Approach 1:
The rounded corner portion is formed as a preliminary feature that acts as a mechanical stop and stress distributor. This preliminary action constrains subsequent material flow during the pushing operation, ensuring the stepped portion forms with proper inclination even with wider clearances between punch and die
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 ensures stable and accurate fitting of the sealing plate, preventing deformation and misalignment, allowing proper welding and maintaining the case's structural integrity.
Implementation Method 1
the sealing plate is welded to the opening of the case by a laser welding method
Implementation Method 2
the ironing is a method of changing a wall thickness by flowing a material plastically along a punch
Data Source
AI summary
A battery case includes a mounting surface formed into a desired shape to place a sealing plate stably thereon. The battery case includes: an open box-shaped case body holding components of a battery; and a sealing plate that is integrated with the case body to close an opening of the case body. A stepped portion on which the sealing plate is placed is formed on an inner wall surface of the case body. The stepped portion includes: a mounting surface on which the sealing plate is placed; an opposed surface opposed to a periphery of the sealing plate placed on the mounting surface; and a depressed corner depressed outwardly from the opposed surface between the mounting surface and the opposed surface.