EV Battery Enclosure Flange Structure for Crack Mitigation
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Solution Overview
Problem
Battery enclosure tubs formed from low strength metallic sheets are vulnerable to spot weld cracks and impact-induced cracking, which can compromise the integrity of the sealed battery enclosure and pose safety risks.
Innovation Solution
The battery enclosure tub includes a flange with crack mitigation regions formed between the outer edge and the inner rim, which are designed to stop, mitigate, or redirect cracks. The tub is formed from a metal sheet using a stamping process, with the crack mitigation regions being thicker than other sections and incorporating features such as beads, openings, or soft zones to enhance crack resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If low strength metallic sheets are used to form the battery enclosure tub, then manufacturing cost and ease of manufacture are improved, but structural strength and crack resistance deteriorate
Solution Approach 1:
The flange incorporates crack mitigation regions with different properties than the rest of the flange. These regions have increased thickness and may include features such as beads, openings, or soft zones that provide enhanced crack resistance specifically where needed, while the rest of the flange maintains its original design for manufacturing efficiency.
2Ease of manufacture
If low strength metallic sheets are used to form the battery enclosure tub, then manufacturing cost is reduced, but reliability under impact loads deteriorates
Solution Approach 1:
The crack mitigation regions are strategically placed in areas most susceptible to impact-induced cracking. By concentrating enhanced material properties only where needed, the design achieves improved reliability without requiring the entire enclosure to be made from high-strength, expensive materials.
Solution Approach 2:
The crack mitigation regions act as pre-designed protective features that cushion against crack propagation before impacts occur. The increased thickness and special features (beads, openings, soft zones) are built in advance to absorb and redirect impact energy, preventing cracks from forming or propagating into critical areas.
3Strength
If the flange thickness is increased to prevent cracking, then crack resistance is improved, but manufacturing cost and device complexity increase
Solution Approach 1:
Instead of uniformly increasing the flange thickness throughout, the design applies increased thickness only in the specific crack mitigation regions where it is most needed. This localized approach provides the necessary crack resistance while minimizing the additional material required and maintaining manufacturing efficiency.
Data Source
AI summary
A battery enclosure and a battery enclosure tub are provided. The battery enclosure tub includes a flange, a wall, and a bottom that is configured to support a battery pack. The flange includes an outer edge, an inner rim defining an opening, and crack mitigation regions formed between the outer edge and the inner rim. The wall extends from the inner rim of the flange, and includes a first portion and a second portion. The first portion is joined to the inner rim of the flange, and the bottom is joined to the second portion of the wall.