EV Rear Rail Structure With Transition-Zone Crash Energy Absorption
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The current rear rail design in electric vehicles, which lacks a fuel tank, is inadequate in absorbing excess crash energy, leading to potential kinetic energy transmission and compromised occupant safety during high-energy rear collisions.
Innovation Solution
A rear rail structure with a transition zone made from a material with a specific fracture strain and critical bending angle, combined with controlled buckling and double bending deformation, to optimize energy absorption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the rear rail design uses controlled buckling for energy absorption, then energy absorption capacity is improved, but remaining crash energy is transmitted to the vehicle body and occupants
Solution Approach 1:
The rear rail is segmented into three distinct zones: rear portion, transition zone, and front portion. Each zone has specific geometric characteristics and material properties optimized for its function. The rear portion with lower strength undergoes controlled buckling, the transition zone with intermediate properties undergoes double bending, and the front portion with higher strength provides anti-intrusion protection.
Solution Approach 2:
Different zones of the rear rail have different material properties and geometric characteristics. The rear portion uses material with lower ultimate tensile strength (700-1000 MPa) for easy buckling, while the front portion uses higher strength material (1000-1500 MPa) for protection. The transition zone uses intermediate strength material (700-1500 MPa) with specific fracture strain (≥0.6) and critical bending angle (≥75°) to enable double bending deformation.
2Loss of energy
If the transition zone and rear portion are designed for controlled deformation, then energy absorption is improved, but structural integrity may be compromised under high-energy crashes
Solution Approach 1:
The patent specifies precise parameter ranges for different zones: rear portion ultimate tensile strength (700-1000 MPa), transition zone ultimate tensile strength (700-1500 MPa) with fracture strain ≥0.6 and critical bending angle ≥75°, front portion ultimate tensile strength (1000-1500 MPa). These parameter changes enable controlled deformation while maintaining structural integrity.
Solution Approach 2:
The rear rail employs a composite structure with different material grades in different zones. The transition zone uses material with intermediate properties between the rear and front portions, creating a gradient structure that facilitates progressive deformation from rear to front while maintaining overall structural integrity.
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
Enhances energy absorption capacity, ensuring controlled deformation sequences and protects critical vehicle components like the battery pack, thereby improving passenger safety and collision resilience.
Implementation Method 1
the transition zone is made from a material having a fracture strain of at least 0.6 and a critical bending angle of at least 75°
Implementation Method 2
it is possible to absorb energy during a rear collision not only through the controlled buckling deformation of the rear section but also through the double bending deformation of the transition zone in its upper and lower bends
Implementation Method 3
the rear portion absorbs energy during a rear collision, through controlled buckling for example
Data Source
AI summary
Rear structure for an electric vehicle having a rear rail which includes a rear portion, a front portion and a transition zone, such that in the event of a rear crash the rear portion and the transition zone are both able to deform to maximize the amount of energy absorption.