Battery Pack Case Sandwich Structure for Compression Without Weight Gain
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Solution Overview
Problem
Existing battery packs face challenges in maintaining a desired compression force for battery stacks while minimizing weight, as traditional methods using bolts and nuts increase pack size and weight, and aluminum die-cast cases require increased rigidity to maintain compression, leading to a heavier pack case.
Innovation Solution
A pack case with a sandwich panel structure comprising metal plates and a lower-density interposed member, which provides higher flexural and torsional rigidity while maintaining a lightweight design, allowing for efficient compression and restraint of battery stacks without significant weight increase.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If aluminum die-cast pack case with increased wall thickness is used to maintain compression force, then compression force is maintained, but pack case weight increases
Solution Approach 1:
The pack case employs a composite structure combining aluminum die-cast metal plates with foam material filling. This composite construction provides high compression resistance through the metal framework while the foam material contributes to structural rigidity without significantly increasing weight, thereby maintaining compression force on the battery stack while avoiding excessive weight gain
2Force
If traditional bolts and nuts are used to restrain battery stack, then compression force is applied, but pack size and weight increase
Solution Approach 1:
The invention extracts and eliminates the need for separate fastening components like bolts and nuts by integrating the compression function directly into the pack case structure. The pack case itself is designed with walls that directly contact and compress the battery stack, simplifying the overall structure and reducing the number of parts required
3Weight of stationary object
If aluminum die-cast pack case is used to reduce weight, then pack case weight is reduced, but rigidity decreases leading to insufficient compression force
Solution Approach 1:
The pack case uses a composite construction where aluminum die-cast metal plates provide structural framework with reasonable weight, while foam material filling enhances the overall rigidity and compression characteristics. This composite approach achieves both weight reduction and sufficient rigidity for maintaining compression force
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 sandwich panel structure effectively suppresses deformation due to reaction forces, maintains compression force, and reduces the overall weight of the pack case, resulting in a lightweight yet rigid battery pack.
Implementation Method 1
The interposed member interposed between and fixed to the first metal plate and the second metal plate has a density lower than that of a metal forming the first metal plate and the second metal plate
Data Source
AI summary
A pack case includes: a first wall pressing a battery stack toward a second side in a stacking direction; and a second wall pressing the battery stack toward a first side in the stacking direction. At least one of the first wall and the second wall is a panel structure wall including a first metal plate, a second metal plate located outward of the first metal plate in the stacking direction and faces the first metal plate, and an interposed member interposed between and fixed to the first metal plate and the second metal plate. The interposed member has a lower density than a metal forming the first metal plate and the second metal plate.