EV Floor Part and Side Sill Welding for Sealed Battery Housing
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The challenge in electric vehicles is to extend the range without increasing the weight of battery cells, which is limited by the need for a robust and watertight battery system.
Innovation Solution
A vehicle body design that incorporates a floor part functioning as an upper battery case, coupled with a side sill through a welding structure that includes friction stir spot welding and metal inert gas welding, to secure airtightness and watertightness without an upper battery case.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the number of battery cells is increased to extend the range of the electric vehicle, then the battery capacity is improved, but the weight of the battery system increases
Solution Approach 1:
The floor part is merged with the upper battery case function, where the floor part itself serves as the upper battery case. This integration eliminates the need for a separate upper battery case, reducing overall weight while maintaining battery capacity. The floor part is configured to cover upper portions of battery modules, thereby functioning as an upper battery case.
Solution Approach 2:
The floor part is designed to perform multiple functions: it serves as both the floor structure and the upper battery case. This multi-functionality reduces the number of separate components needed, thereby reducing weight while maintaining the required battery capacity for extended range.
2Weight of moving object
If the floor part is designed to function as an upper battery case to reduce weight, then the vehicle weight is reduced, but the airtightness and watertightness of the battery system may be compromised
Solution Approach 1:
The floor part is merged with the upper battery case function, creating an integrated structure that maintains airtightness and watertightness through direct welding connections. The first flange of the side sill is welded to the lower surface of the floor part, ensuring sealed connections without requiring additional sealing components.
Solution Approach 2:
Traditional mechanical sealing methods are replaced with welding technology. The first flange is welded to the floor part using friction stir spot welding and MIG welding, providing a more reliable and permanent seal that ensures both airtightness and watertightness while reducing weight.
3Reliability
If the side sill is coupled to the floor part through welding to ensure airtightness and watertightness, then the battery sealing is improved, but the manufacturing complexity increases
Solution Approach 1:
The welding process is segmented into two distinct stages: friction stir spot welding for initial connection and MIG welding for final sealing. This segmentation allows each welding method to be optimized for its specific purpose, simplifying the overall manufacturing process while ensuring reliable sealing.
Solution Approach 2:
Friction stir spot welding is performed first to establish preliminary connections between the side sill and floor part, positioning components accurately. This preliminary action prepares the structure for the subsequent MIG welding that ensures airtightness and watertightness, making the overall manufacturing process more manageable.
4Ease of manufacture
If the floor part is extruded as a single member to simplify manufacturing, then the manufacturing process is simplified, but the structural strength and hardness may be reduced
Solution Approach 1:
The floor part is divided into multiple extruded members that are connected through welding. This segmentation allows each member to be optimized for specific structural requirements, maintaining high strength and hardness while simplifying the extrusion manufacturing process for individual components.
Solution Approach 2:
Multiple extruded members are joined through welding to create a composite structure that achieves the required strength and hardness. The welded connection of multiple members provides structural integrity comparable to or exceeding that of a single large extrusion, while allowing for simpler manufacturing of individual components.
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 design enhances the range of electric vehicles by reducing weight and ensuring perfect airtightness and watertightness, thereby maintaining battery performance and safety.
Implementation Method 1
The lower surface of the floor part and the first flange of the side sill may be coupled to each other in the longitudinal direction of the first flange through friction stir spot welding (FSW) in a surface-contact state.
Implementation Method 2
An area between an upper surface of the floor part and an upper surface of the side sill contacting each other may be welded through metal inert gas (MIG) welding.
Data Source
AI summary
An embodiment body of a vehicle includes a floor part configured as a member molded through an extrusion process, the floor part having a lower surface configured to cover upper portions of battery modules to be accommodated in a lower battery case and a pair of side sills coupled to opposite side surfaces of the floor part and extending in a longitudinal direction of the vehicle, each side sill of the pair of side sills comprising a first flange disposed at an inner surface of the side sill facing the floor part and extending in the longitudinal direction, wherein the first flange is directly coupled to the lower surface of the floor part by a first weld.