Press-Formed Battery Case Corners Using Shear-Deformed Ridge Forming
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Solution Overview
Problem
In manufacturing box-shaped battery cases for electric vehicles, the formation of corners where three ridge lines intersect through press-forming results in a decrease in member thickness due to material flow constraints, making it difficult to achieve both strength, impact resistance, and weight reduction simultaneously.
Innovation Solution
A method involving a multi-step process where a sheet-shaped workpiece is formed into vertical wall portions using a specific die configuration, allowing material to flow and shear-deform to minimize thickness loss, and forming flange-shaped strip portions to maintain structural integrity and strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If high-strength materials are used to achieve strength and impact resistance, then strength and impact resistance are improved, but forming becomes more difficult and member thickness decreases
Solution Approach 1:
The press-forming process is divided into multiple stages: a first press-forming step to form preliminary vertical wall portions, and a second press-forming step to form the corner portions. This segmentation allows each step to be optimized independently, enabling the use of high-strength materials while maintaining formability.
Solution Approach 2:
The first press-forming step performs preliminary forming of vertical wall portions before the corner portions are formed in the second step. This preliminary action prepares the workpiece in a state that facilitates subsequent corner forming with high-strength materials, preventing excessive thickness reduction.
2Strength
If member thickness is increased to achieve strength and impact resistance, then strength and impact resistance are improved, but weight increases leading to decreased fuel efficiency
Solution Approach 1:
The invention changes the forming parameters by using a two-step press-forming process with specific die configurations. This allows achieving the required strength and impact resistance through optimized forming rather than simply increasing material thickness, thereby reducing weight.
3Volume of stationary object
If the radius of curvature of ridge line portions is decreased to maximize battery accommodation space, then space utilization is improved, but material flow is constrained causing significant member thickness reduction
Solution Approach 1:
The forming process is segmented into two distinct steps: the first step forms vertical wall portions with adequate material flow, and the second step forms corner portions with small radii of curvature. This segmentation enables achieving small radii without excessive thickness reduction, as each step is optimized for its specific function.
Solution Approach 2:
The first press-forming step performs preliminary forming to create vertical wall portions that provide a foundation for the subsequent corner forming. This preliminary action ensures that sufficient material is available and properly positioned before the second step creates the space-optimized corner geometry with small radii of curvature.
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 method enables the formation of corners with minimal thickness loss, achieving high strength and impact resistance while maintaining a lightweight structure, suitable for high-strength materials and efficient battery case design.
Implementation Method 1
in the second step, a portion of the second rising portion connected to the vertical ridge line is shear-deformed
Data Source
AI summary
A method for manufacturing a press-formed article (100) includes a first step for forming a base sheet portion, a first rising portion, and a first strip portion from a sheet-shaped workpiece having a first edge portion and a second edge portion; and a second step for forming a second rising portion by causing a strip-shaped first zone including the second edge portion to be disposed between a first upper die and a first lower die from both sides, causing a second zone adjacent to the first zone to be disposed between a second upper die and a second lower die from both sides, and moving the first upper die and the first lower die relative to the second upper die and the second lower die, wherein, in the second step, a part of the second rising portion which is connected to a vertical ridge line (108) is shear-deformed.