Side Sill Reinforcement Layout for Battery-Safe Side Impact Load Paths
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Solution Overview
Problem
Existing vehicle body structures fail to effectively absorb collision loads during a side collision, potentially transmitting them to the battery, which can cause damage.
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 that redirects collision loads away from the battery by transmitting them to the cross member and floor panel.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the second profile member is made with lower breakability to maintain structural integrity, then the battery protection 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 multiple wall portions (outer wall portion, inner wall portion, upper wall portion, lower wall portion) with distinct functions. The outer wall portion absorbs collision energy through controlled deformation, while the inner wall portion and lower wall portion maintain structural integrity to protect the battery, separating the energy absorption function from the protection function.
Solution Approach 2:
The lower wall portion acts as an intermediary element between the collision load path and the battery. It is positioned to support the battery but is designed with specific breakability characteristics that prevent direct transmission of high collision loads to the battery while still providing structural support.
2Ease of manufacture
If the side sill structure is simplified to reduce manufacturing complexity, then the ease of manufacture is improved, but the ability to prevent collision load transmission to the battery deteriorates
Solution Approach 1:
The side sill structure is designed as an integrated component that simultaneously performs multiple functions: absorbing collision energy through controlled deformation of the outer wall portion, maintaining structural integrity through the closed cross-sectional shape, supporting the battery via the lower wall portion, and preventing load transmission to the battery. This multi-functional design avoids the need for separate components for each function.
Solution Approach 2:
The side sill employs a nested wall structure where the inner wall portion is positioned within the outer wall portion, creating a closed cross-sectional structure. This nested configuration provides enhanced structural integrity and collision resistance while maintaining a compact design that is manufacturable as an integrated component.
3Strength
If the inner reinforcement is positioned closer to the lower wall portion to strengthen the structure, then the structural strength is improved, but the collision load is transmitted to the battery
Solution Approach 1:
The inner reinforcement is positioned at specific locations (fixed to the upper wall portion and inner wall portion) rather than uniformly distributed. This localized reinforcement strategy strengthens the side sill structure where needed for collision resistance while deliberately avoiding direct connection to the lower wall portion to prevent load transmission to the battery.
Solution Approach 2:
The inner reinforcement is positioned in the up-down direction at a height that provides structural strength for collision resistance but is spaced apart from the lower wall portion. This vertical positioning creates a dimensional separation between the strength-providing function and the battery support function, preventing direct load transmission.
Data Source
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AI summary
A side sill 2 having a closed cross-sectional structure extending in a vehicle front-rear direction has an outer wall portion 13, an inner wall portion 23, upper wall portions 11, 21, lower wall portions 12, 22, an outer reinforcement 30 fixed to the outer wall portion 13, and an inner reinforcement 40 fixed to the inner upper wall portion 21 and the inner wall portion 23. A cross member 60 extending in a vehicle width direction is fixed to the inner upper wall portion 21, a battery B is supported by the inner lower wall portion 22, the outer reinforcement 30 has an overlapping portion (connection surface portion 33) whose position overlaps a position of the inner reinforcement 40 in an up-down direction, and the inner reinforcement 40 is spaced apart from the inner lower wall portion 22 in the up-down direction.