Battery Pack Case Structure Using Aluminum Sheets for Lower Weight
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Solution Overview
Problem
The existing battery pack cases for electric vehicles are heavy due to the use of extruded aluminum materials, which also lead to productivity issues and dimensional accuracy challenges, and the welding processes like MIG and FSW cause thermal deformation and deterioration.
Innovation Solution
A battery pack case design that minimizes the use of extruded aluminum materials by employing aluminum sheets with spot welding, forming closed sections, and using extruded aluminum components in a controlled manner to reduce weight and improve productivity, while minimizing the occurrence of defective cross-sections and reducing the need for MIG and FSW.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If extruded aluminum materials with complex cross sections are used to reinforce the battery pack case, then the rigidity of the case is improved, but the weight of the case increases
Solution Approach 1:
The battery pack case is divided into multiple components: case panels and multiple extruded aluminum components (front, rear, left, right, first cross, and second cross members). Each component is separately extruded and then assembled together, allowing the structure to achieve required rigidity through the combined effect of multiple simpler components rather than relying on a single complex extrusion
Solution Approach 2:
The battery pack case uses a composite structure combining case panels with multiple extruded aluminum components. The panels and extrusions work together to provide both rigidity and weight efficiency, creating a composite assembly that optimizes the balance between strength and weight
2Strength
If multiple extruded aluminum materials with complex cross sections are used, then the rigidity of the battery pack case is improved, but productivity decreases
Solution Approach 1:
The case structure is segmented into standard extruded components (front, rear, left, right, cross members) that can be manufactured using conventional extrusion processes. These standardized components are easier and faster to produce than a single complex monolithic extrusion, thereby improving productivity while maintaining rigidity through proper structural arrangement
3Strength
If MIG welding and friction stir welding are used to join extruded aluminum components, then the connectivity between components is improved, but thermal deformation and deterioration occur
Solution Approach 1:
The patent replaces thermal welding processes (MIG welding and friction stir welding) with mechanical fastening methods. Fasteners are used to join the extruded aluminum components to the case panels and to each other, eliminating the harmful thermal effects while maintaining strong mechanical connectivity between 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
The solution achieves weight reduction, increased productivity, and improved dimensional accuracy, along with enhanced impact resistance and reduced thermal deformation, by using spot welding and forming closed sections within the battery pack case.
Implementation Method 1
The extruded aluminum components and a case panel are coupled to one another by friction stir welding (FSW)
Implementation Method 2
the extruded aluminum components and a case panel are coupled to one another by friction stir welding (FSW)
Data Source
AI summary
A battery pack case may include: i) a case panel; ii) a case outer frame including at least one aluminum sheet and coupled to edge portions of the case panel; iii) a case inner frame including at least one aluminum sheet and coupled to the edge portions and an upper surface of the case panel; and iv) a case cover coupled to upper portions of the case outer frame and case inner frame.