Vehicle Body Side Floor Cross Extension for Battery Impact Protection
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Solution Overview
Problem
Increasing the width dimension of battery packs in vehicles to enhance mounting capacity results in a decrease in the distance between the battery pack and rockers, leading to higher impact loads during side collisions, necessitating increased withstand strength of the battery pack to maintain impact energy absorption efficiency.
Innovation Solution
A vehicle body side section structure that includes a rocker, a floor cross member, and a floor cross extension, where the floor cross extension is designed to undergo plastic deformation prior to the floor cross member, absorbing impact energy and distributing load to maintain efficiency without increasing battery pack strength, and optional reinforcement to enhance overall withstand strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the battery pack width dimension is increased to enhance mounting capacity, then the battery mounting capacity is improved, but the distance between the battery pack and rockers decreases, resulting in higher impact loads during side collisions
Solution Approach 1:
The floor cross member is segmented into a floor cross extension portion and a main body portion. The floor cross extension portion is positioned between the rocker and the battery pack to specifically address impact protection, while the main body portion maintains structural support. This segmentation allows the extension portion to deform and absorb energy during side collisions, protecting the battery pack without requiring increased battery pack strength.
Solution Approach 2:
The floor cross extension portion acts as an intermediary element between the rocker and the battery pack. During side collisions, this intermediate structure deforms plastically to absorb impact energy, preventing direct transmission of high impact loads to the battery pack. The extension portion serves as a buffer zone that mediates the interaction between the external impact and the battery pack.
2Volume of moving object
If the distance between the battery pack and rockers is reduced, then the battery pack width dimension is increased, but the impact energy absorption efficiency decreases due to short stroke
Solution Approach 1:
The floor cross extension portion extends in the vehicle width direction from the rocker toward the battery pack, creating an additional dimensional space for energy absorption. By utilizing the width direction dimension rather than relying solely on the front-rear direction stroke, the structure compensates for the reduced distance between the battery pack and rocker, maintaining impact energy absorption efficiency despite the shortened stroke.
Solution Approach 2:
The floor cross extension portion is designed with specific material properties and geometric parameters (length, cross-sectional area, wall thickness) that enable controlled plastic deformation. By adjusting these parameters, the extension portion can absorb a predetermined amount of impact energy through deformation, maintaining energy absorption efficiency even when the overall stroke distance is reduced due to increased battery pack width.
3Strength
If the withstand strength of the battery pack is increased to withstand higher impact loads, then the impact energy absorption efficiency is maintained, but the structural weight and complexity increase
Solution Approach 1:
The floor cross extension portion provides beforehand cushioning by being positioned between the rocker and the battery pack. This pre-positioned protective structure is designed to deform during side collisions, absorbing impact energy before it reaches the battery pack. This approach maintains impact energy absorption efficiency without requiring the battery pack itself to have increased withstand strength, thereby avoiding additional weight and complexity.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This configuration allows for effective absorption of impact energy during side collisions, maintaining efficiency without raising the battery pack's withstand strength, even with a short stroke, and enables the overall battery pack's withstand strength to be increased with reinforcement, while minimizing the impact on legroom and structural rigidity.
Implementation Method 1
a floor cross extension that connects the rocker and the floor cross member together in the vehicle width direction, and that is set so as to undergo plastic deformation prior to the floor cross member in a side collision of the vehicle
Data Source
AI summary
Floor cross members provided above a floor panel are disposed so as to form a gap between each of the floor cross members and rockers. A floor cross extension that is set with a lower withstand strength than the floor cross members connects between each of the floor cross members and the corresponding rocker.