Segmented Battery Cage for Crash Protection
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Solution Overview
Problem
Battery packs in electric vehicles are vulnerable to damage during side crashes due to insufficient structural resistance in the underbody and tunnel areas, leading to weight penalties when attempting to reinforce the structure for protection.
Innovation Solution
A lightweight cage structure comprising a top and lower sub-assembly of spaced tubes and U-shaped frames, with a damper system to absorb impact, is designed to encase the battery pack, providing protection and facilitating easy servicing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the underbody structural components (tunnel, cross-members, rocker) are strengthened through up gauging and adding reinforcements, then tunnel collapse resistance is improved, but vehicle weight increases significantly
Solution Approach 1:
The protective structure is divided into two separate sub-assemblies: a top sub-assembly with tubes and inverted U-shaped frames, and a lower sub-assembly with tubes and frames. These sub-assemblies can be independently manufactured and then assembled together, allowing for optimized weight distribution and easier manufacturing while providing comprehensive protection against tunnel collapse.
Solution Approach 2:
The cage structure combines multiple material forms including extruded tubes, cast or formed frames, and foam dampers to create a composite protective system. This composite approach provides high strength-to-weight ratio compared to traditional solid structural reinforcements, effectively resisting tunnel collapse while minimizing weight penalty.
2Reliability
If the battery pack is securely enclosed in the tunnel space, then crash protection is improved, but accessibility for servicing deteriorates
Solution Approach 1:
The cage is segmented into a top sub-assembly and a lower sub-assembly that are joined together. The lower sub-assembly includes a pan that can be removed as a unit, allowing the battery pack to be accessed by simply removing the pan and lower sub-assembly components rather than disassembling the entire structure, thus maintaining crash protection while enabling easy servicing.
Solution Approach 2:
The lower sub-assembly components including the pan are designed to be removable from the vehicle floor, allowing the battery pack to be extracted for servicing. The fasteners connecting the sub-assemblies can be quickly removed, enabling maintenance personnel to access the battery pack without permanently compromising the protective structure.
3Weight of moving object
If a lightweight cage structure is used instead of reinforcing the entire underbody, then vehicle weight is reduced, but crash load absorption capability may be compromised
Solution Approach 1:
The cage employs a composite construction combining lightweight extruded aluminum or steel tubes with cast or formed frame members and foam dampers. This composite structure absorbs crash loads through multiple mechanisms including deformation of the tubular members, crushing of the foam dampers, and energy dissipation at the joint connections, providing adequate crash load absorption while maintaining low weight.
Solution Approach 2:
Foam dampers are pre-installed at critical locations within the cage structure, particularly between the battery pack and the cage members, and between the cage and the vehicle floor. These dampers are designed to compress and absorb impact energy during crash events, protecting the battery pack from direct crash loads while keeping the overall structure lightweight.
Data Source
AI summary
A cage assembly is provided to protect a battery pack in a vehicle. The cage assembly includes a top sub-assembly and a bottom sub-assembly that are secured together to protect the battery pack. U-shaped frames and base frames are connected together by tubular members. A method of making a cage for a battery pack of a vehicle is provided. The method may include assembling a first plurality of spaced tubes and a plurality of spaced inverted U-shaped frames to from a first sub-assembly. The method may also include assembling a second plurality of spaced tubes and a plurality of spaced frames to form a second sub-assembly. The first sub-assembly and the second sub-assembly may be assembled together to enclose the battery pack.