EV Body Floor Structure for Battery Protection in Frontal Overlap Crashes
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Solution Overview
Problem
In electrically drivable motor vehicles, the electrical energy store located below the vehicle floor is at risk of damage during frontal collisions with low width overlap, as the remaining longitudinal members may rotate and cause deformation of the vehicle floor element, potentially leading to intrusion into the energy store's housing.
Innovation Solution
The motor vehicle body features a vehicle floor element with upward embossments behind the connection points of the longitudinal members and targeted weakening of these connection points to prevent excessive deformation and intrusion into the energy store, along with strategically placed connecting elements to reinforce the structure without compromising the connection points.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the longitudinal members are shortened to accommodate the energy store below the vehicle floor, then the space for the energy store is improved, but the ability to transfer forces rearward during collision is worsened
Solution Approach 1:
The embossment is formed in advance on the vehicle floor element at the location where deformation might occur during collision. This pre-formed structural feature prepares the floor element to deform in a controlled manner upward into the embossment during impact, preventing downward deformation that would damage the energy store while maintaining the shortened longitudinal member configuration.
2Strength
If the connection point between the longitudinal member and vehicle floor element is reinforced, then the structural strength is improved, but the risk of pulling down and deforming the vehicle floor element into the energy store during rotation is worsened
Solution Approach 1:
The vehicle floor element is given different structural properties at different locations: the embossment is formed locally at the rearward region behind the connection point to provide controlled deformation capability, while the connection point itself maintains its strength for force transfer. This local differentiation allows the floor element to be strong where needed for connection while being designed to deform safely in a specific region away from the energy store.
3Force
If the longitudinal member rotates about the vehicle transverse axis during frontal collision, then the force distribution is improved, but the vehicle floor element is pulled downwards and deformed towards the energy store is worsened
Solution Approach 1:
The embossment converts the harmful downward deformation of the vehicle floor element during longitudinal member rotation into a beneficial upward deformation. When the longitudinal member rotates and pulls the connection point downward, the floor element deforms upward into the embossment instead of downward into the energy store, transforming a potentially damaging force into a safe deformation path that protects the energy store while still allowing force distribution.
Data Source
AI summary
A motor vehicle body for an electrically drivable motor vehicle includes: a vehicle floor element, which transitions, at the front end of a passenger compartment, into a firewall; longitudinal members of a front-end structure, the rear ends of the longitudinal members being fastened to the firewall and, at a point of connection, to the vehicle floor element; and a stored energy source, which is located below the vehicle floor element and a front end of which is located below the rear ends of the longitudinal members. In order to provide a motor vehicle body with favorable characteristics in a frontal collision with an obstacle or a vehicle, the vehicle floor element has, behind the points of connection to the rear ends of the longitudinal members, respective embossed portions formed upward in the vehicle vertical direction, and/or the points of connection of the rear ends of the longitudinal members to the vehicle floor element have deliberately weakened portions.