Vehicle Lower Body Structure for Side-Impact Battery Load Isolation
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Solution Overview
Problem
Existing vehicle body structures fail to effectively absorb collision energy during a side collision, leading to potential transmission of load to the battery, which is not adequately addressed by existing technologies.
Innovation Solution
A vehicle lower body structure featuring a pair of side sills with a closed cross-sectional design, including outer and inner reinforcements, a cross member, and a specific arrangement to redirect collision loads away from the battery by transmitting them to the cross member and floor panel.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the second profile member is made with high breakability to absorb collision energy, then collision energy absorption is improved, but the collision load cannot be sufficiently absorbed and is transmitted to the battery
Solution Approach 1:
The side sill is divided into two profile members with different breakability characteristics. The first profile member (outer) has higher breakability to absorb initial collision energy, while the second profile member (inner) has lower breakability to maintain structural integrity and prevent load transmission to the battery. This local differentiation of mechanical properties resolves the contradiction between energy absorption and battery protection.
Solution Approach 2:
The side sill structure is segmented into multiple functional components: the first profile member for energy absorption, the second profile member for load path management, and the reinforcement members for structural support. This segmentation allows each component to perform its specific function optimally, preventing overload transmission to the battery while maintaining adequate energy absorption.
2Strength
If the inner reinforcement is positioned close to the lower wall portion to support the battery, then battery support is improved, but collision load is transmitted to the battery
Solution Approach 1:
The inner reinforcement acts as an intermediary element positioned between the collision load path and the battery. It is fixed to the upper and inner wall portions but spaced apart from the lower wall portion, creating a load isolation zone. This intermediary positioning allows the reinforcement to manage collision loads while preventing direct load transmission to the battery, resolving the contradiction between support and protection.
Solution Approach 2:
The inner reinforcement is positioned in the vertical dimension (spaced apart from the lower wall portion) rather than being directly adjacent to it. This vertical spacing creates a dimensional buffer zone that interrupts the direct load path from the collision to the battery, while the reinforcement still provides structural support through its fixation to other portions of the side sill.
Data Source
AI summary
A vehicle lower body structure prevents transmission of a collision load to a battery during a side collision. A side sill having a closed cross-sectional structure extending in a vehicle front-rear direction has an outer wall portion, an inner wall portion, upper wall portions, lower wall portions, an outer reinforcement fixed to the outer wall portion, and an inner reinforcement fixed to the inner upper wall portion and the inner wall portion. A cross member extending in a vehicle width direction is fixed to the inner upper wall portion. A battery is supported by the inner lower wall portion. The outer reinforcement has an overlapping portion (connection surface portion) whose position overlaps a position of the inner reinforcement in an up-down direction, and the inner reinforcement is spaced apart from the inner lower wall portion in the up-down direction.