EV Battery Case Corner R Geometry for Sealing and Crack Resistance
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing battery cases for electric vehicles face challenges in securing a sufficient sealing property, improving space efficiency for battery mounting, preventing cracking during molding, and enhancing the joining strength of the tray and frame, particularly due to the need for mold draft angles and R shapes in cold press molding.
Innovation Solution
A battery case design featuring a polygonal frame with R-shaped corner members and a bathtub-shaped tray, where the tray is pressure-welded to the frame, eliminating seams and allowing for precise R-shape matching, thereby improving space efficiency and joining strength while preventing cracking and thermal deformation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If cold press molding is performed on the metal plate to create a bathtub-shaped tray, then the sealing property is improved, but the corner parts are at risk of cracking due to high-load press molding and small R shapes
Solution Approach 1:
R shapes are provided to the corner parts of the frame in advance before the tray molding process. This preliminary action prepares the frame structure to accommodate the tray corner parts with adequate curvature, preventing stress concentration and cracking during the subsequent high-load press molding operation.
2Ease of manufacture
If high-load press molding is performed to create the bathtub shape, then the tray structure is formed, but the corner parts are at risk of cracking
Solution Approach 1:
The frame is pre-formed with R shapes at its corner parts before the tray molding process. This preliminary preparation ensures that when high-load press molding is applied to form the bathtub-shaped tray, the corner parts have sufficient curvature to distribute stress and prevent cracking, enabling both easy manufacture and structural integrity.
3Strength
If the tray is welded to the frame, then the joining strength is improved, but thermal deformation occurs
Solution Approach 1:
The patent replaces the thermal welding process with a mechanical pressure-welding process. The tray flange part is pressed against the frame by a pressing device, creating a mechanical connection through pressure rather than heat. This substitution eliminates thermal deformation while achieving the necessary joining strength between the tray and frame.
4Volume of moving object
If R shapes are made small to secure large battery mounting space, then space efficiency is improved, but the tray corner parts are at risk of cracking
Solution Approach 1:
R shapes are pre-provided to the corner parts of the frame before tray formation. This preliminary action ensures that even when the tray corner parts are formed with minimal R shapes to maximize battery mounting space, the underlying frame structure provides the necessary curvature support to prevent cracking during the molding process.
Solution Approach 2:
The frame acts as an intermediary structure that provides R shapes at its corner parts. This intermediary element allows the tray corner parts to have minimal R shapes for space efficiency while the frame's R shapes prevent stress concentration and cracking during molding, mediating between the conflicting requirements of space and strength.
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 provides a battery case with enhanced sealing properties, improved space efficiency for battery mounting, and increased joining strength between the tray and frame, reducing the risk of cracking and thermal deformation during molding.
Implementation Method 1
a battery case whose sealing property is improved by using a tray obtained by molding a metal plate into a bathtub shape by cold press molding
Data Source
AI summary
A battery case for an electric vehicle includes a frame that has a polygonal frame shape in plan view, defines a through hole inside, and has R shapes provided on inner sides of corner parts of the polygonal frame shape. The case also includes a bathtub-shaped tray that includes a bottom wall located in the through hole, a surrounding wall that is provided around the bottom wall and defines an opening part on a side opposite to the bottom wall, and a flange that is provided at a distal end of the surrounding wall. The tray is pressure-welded to and integrated with the frame.