Hybrid Rear Body Structure for EV Battery Impact Load Distribution
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Solution Overview
Problem
The challenge lies in enhancing the rear impact performance of vehicle bodies, particularly in electric vehicles with large batteries, to prevent battery damage during collisions while maintaining a robust structure and reducing weight.
Innovation Solution
A vehicle body rear structure incorporating a CFRP cabin, a steel cross member within a CFRP rear module mounting panel, and a steel rear module mounting panel with specific load paths and reinforced connections to distribute collision loads effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If CFRP material is used for the cabin to reduce weight, then the weight of the vehicle body is reduced, but the mechanical coupling and structural strength at the rear require additional reinforcement
Solution Approach 1:
The patent employs a hybrid material system combining CFRP (carbon fiber reinforced plastic) for the cabin and steel for the cross member and mounting panel. This composite material approach allows the lightweight CFRP to be used where weight reduction is critical while steel provides the necessary strength and rigidity for load-bearing rear structures, resolving the contradiction between weight reduction and structural strength
Solution Approach 2:
The patent applies different material properties to different regions of the vehicle body. The CFRP cabin uses lightweight material where weight reduction is prioritized, while the steel cross member and mounting panel are strategically positioned at the rear structure where high strength is required. This localized material selection optimizes both weight and strength requirements
2Reliability
If the vehicle body structure is reinforced to prevent battery damage in collisions, then the crash performance is improved, but the weight of the vehicle increases
Solution Approach 1:
The hybrid CFRP-steel construction provides enhanced crash performance through the complementary properties of both materials. The steel cross member and mounting panel offer high strength and rigidity for impact resistance, while the CFRP cabin maintains lightweight characteristics, achieving reliable crash protection without excessive weight increase
Solution Approach 2:
The patent divides the rear structure into functionally distinct segments: the CFRP cabin, the steel cross member, and the steel mounting panel. This segmentation allows each component to be optimized for its specific function - the cabin for lightweight occupancy space, the cross member for structural rigidity, and the mounting panel for battery module attachment - achieving reliable crash performance through coordinated design rather than uniform reinforcement
3Reliability
If multiple separate components are used for the rear module mounting structure to ensure strength, then the structural reliability is improved, but the number of parts and device complexity increase
Solution Approach 1:
The patent merges the cross member and mounting panel into an integrated assembly where the steel cross member is positioned within the CFRP mounting panel. This merging reduces the number of separate components while maintaining structural reliability, as the combined structure provides both the rigidity of the cross member and the mounting functionality of the panel, eliminating the need for additional connection hardware
Data Source
AI summary
A vehicle body rear structure includes a cabin, a cross member, and a rear module mounting panel connected to the cabin, at least a portion thereof contacting with the cross member and the rear module mounting panel of which a mounting portion connected to a body rear element is formed thereto, and the cross member is disposed within the rear module mounting panel.