Battery Pack Covering Structure With RIM Core for Low-Weight Strength
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current battery pack designs face challenges in achieving lightweight, high mechanical strength, and flame resistance, particularly in the upper cover and bottom tray, where metal materials are heavy and injection molding of polypropylene or polyamide is costly and difficult for large components.
Innovation Solution
A battery pack design featuring a reaction injection molded (RIM) polyurethane core layer with metal face sheets on both sides, allowing for a 3D shape and rib pattern optimization, and a bending/welding process for metal sheets to form the bottom tray, which reduces weight while maintaining mechanical strength and flame resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If metal sheets are used for upper cover and bottom tray, then mechanical strength is improved, but weight increases
Solution Approach 1:
The patent applies composite materials by combining metal face sheets with a polyurethane foam core layer to create a sandwich structure. This composite construction provides the mechanical strength of metal while significantly reducing weight compared to solid metal components, directly resolving the contradiction between strength and weight.
Solution Approach 2:
The sandwich structure applies local quality by concentrating metal face sheets only where structural strength is needed (at the surfaces), while the core layer provides lightweight filling. This localized material distribution optimizes the strength-to-weight ratio by placing materials strategically rather than uniformly throughout the entire component.
2Weight of moving object
If polypropylene or polyamide injection molding is used for upper cover, then weight is reduced, but manufacturing cost and difficulty increase for large components
Solution Approach 1:
The patent uses a composite sandwich structure with a polyurethane foam core and metal face sheets, which can be manufactured through reactive injection molding (RIM). This process is particularly suitable for large components and avoids the high tooling costs and processing difficulties associated with molding large polypropylene or polyamide parts, while still achieving weight reduction.
Solution Approach 2:
The patent changes the material parameter from solid thermoplastics (polypropylene/polyamide) to a foam-based composite structure. This parameter change enables weight reduction while simplifying the manufacturing process for large components, as the foam core can be injected directly into large molds without requiring complex high-pressure molding operations.
3Weight of moving object
If sandwich structure with foam core is used, then weight is reduced, but mechanical strength and flame resistance must be maintained
Solution Approach 1:
The sandwich structure combines a lightweight polyurethane foam core with dense metal face sheets. The foam core provides weight reduction, while the metal face sheets maintain mechanical strength and provide flame resistance. This composite approach allows the structure to meet both weight reduction goals and performance requirements simultaneously.
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
The RIM-based battery pack achieves significant weight reduction, enhanced mechanical strength, and improved flame resistance, with the rib pattern design and sealing groove enhancing stiffness and water tightness.
Implementation Method 1
providing bottom tray, comprising the steps of 1) bending flat metal sheets into target 3D shape top and bottom metal face sheets and welding at the open corner; 2) fixing the top and bottom metal face sheets into a RIM mold, and then closing the mold; 3) injecting the reactants into the hollow space cavity between metal face sheets to form molded core layer via reaction injection molding (RIM process)
Data Source
AI summary
Disclosed herein are a 3D shape covering article including a reaction injection molded product as core layer and two metal sheets located on both sides of the core layer, a battery pack including the covering article, and a process for preparing the battery pack.