Battery Pack Waterproofing via Segmented Flanges and Depending Walls
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Solution Overview
Problem
Conventional battery packs for electric vehicles lack sufficient waterproofing, particularly when submerged in water, leading to potential water intrusion into the battery chamber.
Innovation Solution
The battery pack design includes an upper and lower case with flanges, a seal member, and threaded bolts and nuts for secure joining, along with a rib on the upper case flange for enhanced stiffness and a resin-filled space between depending walls to improve waterproofing, preventing water intrusion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional battery pack design is used, then the structure is simple, but the waterproof performance is insufficient when submerged in water
Solution Approach 1:
The battery pack is divided into upper and lower cases with separate flanges and depending walls. The upper case-side flange and lower case-side flange are segmented components that can be independently manufactured and assembled, allowing for optimized waterproof design at each segment while maintaining overall structural integrity.
Solution Approach 2:
Depending walls extend vertically downward from the flanges beyond the opposing flange, creating a multi-dimensional barrier against water intrusion. This vertical extension adds a new dimensional element to the waterproof design, preventing water entry from multiple angles when the battery pack is submerged.
2Reliability
If flange structure is added for waterproofing, then the waterproof performance is improved, but the manufacturing complexity increases
Solution Approach 1:
The flange structure is segmented into upper case-side flange and lower case-side flange, each with specific functions. This segmentation allows each flange to be optimized for its specific role in waterproofing while simplifying the manufacturing process for each individual component.
Solution Approach 2:
The flanges serve multiple functions: mechanical joining of the battery pack cases, sealing surface for the seal member, and structural support for the depending walls. This multi-functionality reduces the need for separate components, simplifying manufacturing while maintaining waterproof performance.
3Reliability
If seal member is interposed between flanges, then the waterproof performance is improved, but the assembly complexity increases
Solution Approach 1:
The seal member is pre-installed on the lower case-side flange before assembly, creating a ready-to-seal surface. This preliminary action ensures proper seal member positioning and orientation, simplifying the final assembly process while guaranteeing waterproof performance.
Solution Approach 2:
The seal member acts as an intermediary element between the upper and lower flanges, creating a flexible sealing interface that accommodates manufacturing tolerances and assembly variations. This intermediary component simplifies the assembly process by providing a forgiving interface that maintains waterproofing despite minor misalignments.
4Reliability
If depending walls are added beyond the flange, then the waterproof performance is improved, but the device complexity increases
Solution Approach 1:
The depending walls are merged with the flange structures, forming an integrated waterproof barrier. The upper case-side depending wall extends from the upper case-side flange, and the lower case-side depending wall extends from the lower case-side flange, combining sealing and structural functions in a single integrated design.
Solution Approach 2:
The depending walls extend vertically beyond the horizontal flange structures, adding a vertical dimension to the waterproof barrier. This vertical extension creates a multi-layered defense against water intrusion from below, improving waterproof performance without requiring separate components.
Data Source
AI summary
A battery pack includes: an upper case having an upper-case side flange and a lower case having a lower-case side flange opposing the upper case-side flange, wherein the battery pack is provided with an upper case-side depending wall that depends from an outer edge of the upper case-side flange beyond the lower case-side flange, with the upper case-side depending wall being spaced from an outer edge of the lower case-side flange, and a lower case-side depending wall that depends from the outer edge of the lower case-side flange.