Vehicle Lower Body Structure for Side-Impact Battery Load Redirection
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Solution Overview
Problem
Existing vehicle body structures for hybrid or electric vehicles fail to effectively absorb collision energy during a side collision, leading to potential transmission of collision loads to the battery, which is not adequately addressed by existing breakable profile members.
Innovation Solution
A vehicle lower body structure featuring a pair of side sills with outer and inner reinforcements, a cross member, and load transmission promoting portions that redirect collision loads away from the battery by transmitting them to the cross member via overlapping and rigidly fixed components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If only a first profile member with breakability is used for side collision energy absorption, then the structure complexity is reduced, but the collision load cannot be sufficiently absorbed and may be transmitted to the battery
Solution Approach 1:
The side sill structure is segmented into multiple functional components: an outer profile member (first reinforcement) positioned on the outer side, and an inner profile member (second reinforcement) positioned on the inner side. Each segment has specific breakability characteristics - the outer profile member is designed to break first to absorb collision energy, while the inner profile member maintains higher strength to prevent load transmission to the battery. This segmentation allows the system to handle different stages of collision energy absorption effectively.
Solution Approach 2:
Different parts of the side sill structure are assigned different mechanical properties tailored to their specific functions. The outer profile member has lower breakability (higher strength) to initially resist collision, while the inner profile member has higher breakability (lower strength) to fail safely without transmitting load to the battery. This local differentiation of material properties optimizes the overall collision response of the structure.
2Reliability
If the second profile member is designed with high breakability to absorb collision energy, then the battery protection is improved, but the collision load may not be sufficiently absorbed before reaching the battery
Solution Approach 1:
The outer profile member is designed to perform preliminary action by breaking first during collision to absorb a significant portion of the collision energy. This preliminary energy absorption reduces the load that reaches the inner profile member and battery, allowing the inner profile member to maintain higher breakability for battery protection without compromising overall collision load absorption.
3Ease of manufacture
If a single reinforcement member is used in the side sill, then the manufacturing cost is reduced, but the collision load transmission to battery cannot be effectively prevented
Solution Approach 1:
The inner profile member acts as an intermediary element between the outer profile member and the battery. It receives collision loads from the outer profile member through the floor panel and cross member, and is designed to fail in a controlled manner that prevents load transmission to the battery. This intermediary component effectively mediates the force transmission path to protect the battery while maintaining reasonable manufacturing complexity.
Data Source
AI summary
A vehicle body structure prevents transmission of a collision load during a side collision to a battery. An outer reinforcement is fixed to an outer wall portion of a side sill, and an inner reinforcement having a vertical surface portion is fixed to an inner upper wall portion and an inner wall portion of the side sill. A cross member extending in a vehicle width direction is fixed to the inner upper wall portion of the side sill. The outer reinforcement has an overlapping portion (a connection surface portion), a position of which overlaps a position of the inner reinforcement in an up-down direction. The vertical surface portion has a load transmission promoting portion, a position of which overlaps a position of the cross member in a vehicle front-rear direction, and which transmits a collision load during a side collision to the cross member.