Bus Bar Elastic Deformation for Welding Defect Detection
Solution Overview
Problem
Conventional battery packs face challenges in detecting welding defects between bus bars and electrodes, as electrical inspections may fail to detect issues when the bus bar is not properly welded due to gaps or improper contact.
Innovation Solution
The battery pack design includes a bus bar module with a base member and extending portions that are welded to the electrodes while applying stress away from them, allowing for detection of welding defects through electrical conductivity checks after elastic deformation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the bus bar is welded to the electrodes without applying stress, then the welding process is simple, but welding defects cannot be reliably detected through electrical inspection
Solution Approach 1:
The bus bar is pre-deformed to apply stress during welding, ensuring that any welding defect will result in separation. This preliminary preparation of the stress state enables reliable defect detection through subsequent electrical inspection, while maintaining a relatively simple welding process.
Solution Approach 2:
The stress state of the bus bar is changed during welding by applying elastic deformation. This parameter change ensures that the bus bar is under tension during welding, so that welding defects cause separation and prevent electrical contact, making defects detectable through electrical inspection.
2Reliability
If the bus bar is welded to the electrodes with stress applied away from the electrode, then welding defects can be detected, but the welding process becomes more complex
Solution Approach 1:
The bus bar is pre-deformed to apply stress during welding, ensuring that any welding defect will result in separation. This preliminary preparation of the stress state enables reliable defect detection through subsequent electrical inspection, while maintaining a relatively simple welding process.
Solution Approach 2:
The bus bar's own elastic deformation provides the stress needed for defect detection. The material's inherent elastic properties are utilized to create the tensile stress condition, eliminating the need for external stress application mechanisms and reducing overall system complexity.
3Productivity
If the bus bar is welded to the electrodes without elastic deformation, then the manufacturing process is simpler, but welding defects may remain undetected
Solution Approach 1:
The bus bar is pre-deformed to apply stress during welding, ensuring that any welding defect will result in separation. This preliminary preparation of the stress state enables reliable defect detection through subsequent electrical inspection, while maintaining a relatively simple welding process.
Solution Approach 2:
The bus bar's own elastic deformation provides the stress needed for defect detection. The material's inherent elastic properties are utilized to create the tensile stress condition, eliminating the need for external stress application mechanisms and reducing overall system complexity.
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
This method reliably detects welding defects by ensuring the bus bar is not in contact with the electrodes when a defect occurs, allowing for accurate electrical inspection and improved manufacturing quality.
Implementation Method 1
the first extending portion is welded to the first electrode in a state where stress is applied to the first extending portion in a direction away from the first electrode
Data Source
AI summary
A battery pack includes a battery stack composed of a stack of multiple battery cells and a bus bar module fixed to the battery stack. Electrodes are provided on a specific surface of each of the battery cells. The battery stack has a surface composed of the specific surface of each of the multiple battery cells. The bus bar module includes a base member and a bus bar. The base member is fixed on the surface of the battery stack. The bus bar includes a fixed portion fixed to the base member and a first extending portion extending from the fixed portion to a first electrode of the electrodes of each of the multiple battery cells. The first extending portion is welded to the first electrode in a state where stress is applied to the first extending portion in a direction away from the first electrode.