Vehicle Battery Case Bracket Structure for Collision Load Transfer
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Solution Overview
Problem
Existing vehicle lower-portion structures that integrate a crossmember with a cover plate serving as a floor panel can compromise battery performance due to the need for direct fixation, which affects the integrity and functionality of the battery.
Innovation Solution
A vehicle lower-portion structure that includes a crossmember extending in the vehicle-width direction, with a bracket and fastener system that avoids direct fixation to the battery case, using a bracket with a joining portion and fastening portion to secure the crossmember, and incorporates a recessed design to enhance reinforcement and absorption of collision loads.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the crossmember is directly fixed to the cover plate by forming a hole in the cover plate, then the crossmember can be securely attached to transmit collision loads, but the performance of the battery may be affected due to the hole formation
Solution Approach 1:
A bracket is introduced as an intermediary component between the crossmember and the battery case. The bracket includes a joining portion that attaches to the battery case and a fastening portion that secures the crossmember, eliminating the need to form holes directly in the battery case while still enabling collision load transmission.
2Reliability
If the bracket is provided between the battery case and the crossmember with a fastening portion, then direct fixation to the battery case is avoided protecting battery performance, but the structure complexity increases
Solution Approach 1:
The bracket integrates multiple functions into a single component: it provides structural support, serves as the joining portion attached to the battery case, and includes the fastening portion for securing the crossmember. This merging approach adds minimal complexity while achieving multiple objectives.
3Strength
If the fastener is inserted through the bracket and crossmember, then the crossmember and battery case are securely fixed, but the fastener may come off from the bracket
Solution Approach 1:
The bracket includes a protrusion that extends toward the battery case, creating a physical barrier that prevents the fastener from detaching. This beforehand cushioning feature ensures that the fastener remains retained even under vibration or collision conditions while maintaining secure fastening.
4Strength
If the bracket outer side bends along the battery case side surface, then the bracket reinforces the battery case side surface, but the manufacturing complexity increases
Solution Approach 1:
The bracket is designed with distinct functional segments: a joining portion for attachment to the battery case, a fastening portion for securing the crossmember, and an outer side that bends along the side surface for reinforcement. This segmentation allows each portion to be optimized independently for its specific function while simplifying the overall manufacturing process.
Data Source
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AI summary
A vehicle lower-portion structure includes a battery case (12) disposed in a lower portion of a vehicle, the battery case accommodating a battery (BT), a crossmember (20) disposed on a vehicle upper side from the battery case (12), the crossmember (20) extending in a vehicle-width direction, a bracket (40) provided between the battery case (12) and the crossmember (20), the bracket (40) including a joining portion (40A) joined to an upper surface of the battery case (12) and a fastening portion (40B) having an insertion hole (41A), and a fastener (44) provided through the insertion hole (41A) to fix the crossmember (20) and the battery case (12).