Traction Battery Rail with Stiffness Gradient for Side Impact
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Solution Overview
Problem
The increased weight of traction battery units in electric or hybrid vehicles enhances deformation forces and energy absorption during a side impact, leading to potential damage and inefficient energy dissipation in existing vehicle designs.
Innovation Solution
A battery side member with a cross-sectional design featuring a first portion with higher stiffness near the traction battery unit and a second portion with lower stiffness near the sill side section, made of metallic materials like aluminum, allows preferential deformation during a side impact, thereby improving energy absorption and maintaining battery integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a battery side member with uniform stiffness is used, then the structure is simple to manufacture, but the energy absorption during side impact is insufficient due to the increased mass of traction batteries
Solution Approach 1:
The battery side member is designed with a non-uniform cross-section where the first portion (near the battery unit) has different dimensions than the second portion (near the sill side section). Specifically, the first portion has a greater distance between opposite walls than the second portion, creating a gradient in stiffness along the lateral direction. This local variation in geometry allows the structure to optimize energy absorption during side impact while maintaining manufacturability through a single extrusion process.
2Loss of energy
If the second portion has reduced material surface working in transverse compression (less than 70% of the first portion), then preferential deformation occurs during side impact, but the manufacturing precision requirements increase
Solution Approach 1:
The invention changes the geometric parameters of the battery side member cross-section along its length. The first portion has a greater distance between opposite walls compared to the second portion, creating a controlled gradient in stiffness. This parameter variation is achieved through extrusion process control, where the non-uniform cross-section is formed as a single continuous structure. The design ensures that the second portion has reduced material surface working in transverse compression (less than 70% of the first portion), enabling preferential deformation during side impact to dissipate energy efficiently.
3Stability of the object's composition
If the battery side member is made as a single extruded piece with varying cross-section, then structural integrity is maintained while enabling controlled deformation, but the manufacturing complexity increases
Solution Approach 1:
The battery side member cross-section is segmented into distinct portions (first portion near the battery unit and second portion near the sill side section) with different geometric characteristics. Each portion has a specific distance between opposite walls, creating zones of different stiffness. Despite this segmentation in geometry, the entire structure is manufactured as a single extruded piece, maintaining structural integrity while enabling controlled deformation behavior during side impact.
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
This configuration enhances the deformation behavior of partially electric vehicles by reducing deceleration values during a side impact, ensuring the battery's protection and efficient energy dissipation without additional structural modifications or costs.
Implementation Method 1
the second portion deforms preferentially with respect to the first portion during a side impact on the vehicle on the side of said battery side member
Data Source
Figure 1~2
Figure 3
AI summary
The invention relates to a partially electric motor vehicle comprising: a floor (3); two side sill profiles (15) arranged either side of the floor (3); a traction battery unit (7) beneath the floor (3) and between the two profiles (15); and at least one battery rail (23) arranged laterally between the traction battery unit (7) and at least one of the two side sill profiles (15), respectively. The battery rail (23) also has a cross-section with a first portion (25) arranged on the side of the traction battery unit (7) and a second portion (27) arranged on the side of the corresponding side sill profile (15), said second portion (27) having a lower transverse compression stiffness than the first portion (25).