Side Sill and Cross Member Joint for EV Side-Impact Loads
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Solution Overview
Problem
The existing vehicle body structures are vulnerable to side collisions, particularly when mounting high-capacity batteries, as the installation space for energy-absorbing members is insufficient, leading to potential penetration of collision loads into passenger and battery spaces.
Innovation Solution
A vehicle body design featuring a side sill with an inner and outer panel, a reinforcing member between them, and a cross member with an inclined end that corresponds to the side sill's inclined surface, enhancing the connection rigidity and energy absorption during side collisions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If a high-capacity battery is mounted in the vehicle, then the energy storage capacity is improved, but the installation space for energy-absorbing members becomes insufficient, making the vehicle vulnerable to side collisions
Solution Approach 1:
The side sill is divided into multiple components: inner panel, outer panel, and reinforcing member disposed between them. This segmentation allows the structure to maintain strength while reducing the space required for energy-absorbing members, enabling battery installation without compromising side collision resistance.
Solution Approach 2:
The reinforcing member is nested between the inner panel and outer panel of the side sill, creating a compact multi-layer structure. This nesting arrangement maximizes structural strength within limited space, allowing both high energy storage capacity and adequate collision protection.
2Reliability
If a reinforcing member is added to the side sill to improve energy absorption, then the side collision resistance is improved, but the device complexity increases
Solution Approach 1:
The connection structure merges the cross member and reinforcing member into a single integrated unit through continuous welding along the inclined surface. This combining approach improves side collision resistance while avoiding the complexity of multiple separate connection components.
3Strength
If ultra-high strength steel of 780 MPa or more is used to strengthen the connection structure, then the side collision resistance is improved, but the formability decreases, limiting the shape of the connection structure
Solution Approach 1:
The connection structure employs an inclined surface with curved geometry that gradually transitions between components. This curved design maintains excellent formability despite using ultra-high strength steel, while achieving superior connection strength for side collision resistance.
Data Source
AI summary
A vehicle body according to an embodiment of the present invention may comprise: a side sill extending in the lengthwise direction of a vehicle; and a cross member extending in the widthwise direction of the vehicle and coupled at an end thereof to the side sill, wherein: the side sill comprises an inner panel, an outer panel coupled to the inner panel, an outer panel coupled to the inner panel, and a reinforcement member disposed between the inner panel and the outer panel; the inner panel includes an inclined surface formed to have an ascending slope from the inner side to the outer side of the vehicle; the end of the cross member is formed to have a slope corresponding to the inclined surface and is coupled to the outer surface of the inclined surface; and one end of the reinforcement member is coupled to the inner surface of the inclined surface.