Battery Module Cell Stack Insertion Under High Mechanical Prestress
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Solution Overview
Problem
Existing methods for inserting a cell stack into a battery module housing result in uneven loading and potential damage to the cells due to localized stress, especially with high mechanical prestress, leading to frictional resistance and insufficient insertion.
Innovation Solution
A process arrangement using tension plates with sliding films and a tie rod to maintain and evenly distribute mechanical prestress during the insertion, ensuring uniform loading and protection of the cells.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If high mechanical prestress is applied to the cell stack during insertion, then the cell stack can be securely positioned in the module housing, but localized stress and pressure points form on the cell membrane causing damage
Solution Approach 1:
A tension plate is introduced as an intermediary component between the tie rod and the cell stack. The tension plate distributes the insertion force from the tie rod across its entire surface area, preventing localized stress concentration on the cell membrane while maintaining the necessary mechanical prestress for secure positioning
Solution Approach 2:
The tension plate changes the distribution parameter of the applied force from concentrated (at the tie rod contact point) to distributed (across the tension plate surface). This parameter change allows high mechanical prestress to be applied without creating damaging pressure points on the cell membrane
2Stability of the object's composition
If compression forces are increased to accommodate cell swelling in more powerful cells, then the cell stack remains stable, but frictional resistance increases making insertion into the module housing insufficient
Solution Approach 1:
The tension plate is pre-positioned on the cell stack before insertion, and the tie rod is connected to the tension plate beforehand. This preliminary arrangement ensures that the force distribution mechanism is already in place, allowing smooth insertion without increasing frictional resistance
Solution Approach 2:
The tension plate acts as a mediator that decouples the relationship between the tie rod and the cell stack. It allows the cell stack to be pulled into the housing through the tension plate without direct contact between the tie rod and cells, reducing frictional resistance while maintaining stability
3Force
If the workpiece carrier remains permanently attached to the cell stack during drawing-in, then the cell stack remains mechanically prestressed, but the insertion process becomes more complex and time-consuming
Solution Approach 1:
The system is segmented into distinct functional components: the workpiece carrier for initial holding, the tension plate for force distribution and prestress maintenance, and the tie rod for insertion. This segmentation allows each component to be optimized for its specific function and easily removed after serving its purpose
Solution Approach 2:
The tension plate is extracted from the cell stack after insertion is complete, and the workpiece carrier is removed. Only the essential tie rod remains attached to maintain mechanical prestress, simplifying the final assembly while preserving the necessary force application
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 allows for the cell stack to be drawn into the module housing without damage, even under high mechanical prestress, by using tension plates and sliding films to distribute forces uniformly and prevent localized stress.
Implementation Method 1
Each of the tension plates (27) has a sliding film (31) positioned as a loop-shaped double layer between the respective tension plate (27) and the adjacent cell stack end
Data Source
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AI summary
The invention relates to a process arrangement for producing a battery module with a module housing (1) in which a cell stack, in particular made of pouch cells, is arranged, which is subjected to a mechanical prestress (Fv) in a stacking direction between module housing walls (5, 7), with a pressing station in which the cell stack can be placed under mechanical prestress (Fv) in a pressing process by means of a workpiece carrier (21), and with a pulling-in station in which a tension rod (43) pulls the cell stack from the workpiece carrier (21) into the module housing (1) in a pulling-in process while maintaining the mechanical prestress (Fv). According to the invention, tension plates (27) are provided as assembly aids for maintaining and/or evenly distributing the mechanical prestress (Fv) of the cell stack during the pulling-in process.