Battery Module Case Welding with Gas-Relief Tunnel Structure
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Solution Overview
Problem
Existing battery module manufacturing methods result in appearance defects such as weld burst marks due to gas ejection during welding, particularly when using aluminum cases manufactured by die casting.
Innovation Solution
The implementation of a tunnel portion between coupling portions of aluminum cases, manufactured by different methods (die casting and rolling/extrusion), which distributes gas ejection pressure and prevents surface swelling by allowing gas discharge through recessed areas, thereby improving welding quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If aluminum cases are welded together, then strong bonding force is achieved, but appearance defects such as weld burst marks occur due to gas ejection
Solution Approach 1:
The patent extracts the harmful gas ejection from the welding area by creating a tunnel portion that directs gas away from the welding portion. The tunnel portion serves as an extraction path that separates the gas flow from the critical welding and surface areas, allowing welding to proceed without appearance defects.
Solution Approach 2:
The tunnel portion acts as an intermediary structure between the welding portion and the external environment. It mediates the gas ejection process by providing a controlled path for gas discharge, preventing direct contact between ejected gas and the welding area, thus protecting the welding quality while maintaining the welding process.
2Manufacturing precision
If gas ejection is prevented during welding, then appearance quality improves, but welding process becomes more difficult
Solution Approach 1:
The patent introduces a spatial dimension solution by creating a tunnel portion that extends in a direction away from the welding surface. This three-dimensional structure provides a dedicated gas ejection path that does not interfere with the two-dimensional welding process, allowing both high appearance quality and ease of manufacture.
Solution Approach 2:
The module case is segmented into distinct functional portions: the welding portion for strong bonding, the tunnel portion for gas ejection, and the coupling portions for structural connection. This segmentation allows each portion to optimize its specific function without compromising the others, making the overall manufacturing process easier while maintaining appearance quality.
3Manufacturing precision
If tunnel portion is added to module case, then welding quality improves, but device complexity increases
Solution Approach 1:
The tunnel portion is designed to serve multiple functions: it acts as a gas ejection path during welding, provides structural support as part of the module case, and can serve as a mounting feature for other components. This multi-functionality reduces the need for additional separate features, thereby limiting the increase in device complexity while achieving improved welding quality.
Solution Approach 2:
The tunnel portion is merged with the coupling portions of the module case, forming an integrated structure. Rather than being a separate added component, the tunnel is formed as part of the case itself, combining the case structure and gas ejection function into a single element, thus minimizing the increase in device 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
The solution enhances welding quality by preventing appearance defects and reducing manufacturing costs while maintaining strong bonding forces.
Implementation Method 1
allowing gas discharge through recessed areas, thereby improving welding quality
Implementation Method 2
a welding portion in which a boundary area of the first coupling portion and the second coupling portion is welded
Data Source
AI summary
A battery module according to the present disclosure comprises a cell stack comprising a plurality of battery cells; and a module case covering the outside of the cell stack. A module case comprises a first case comprising a rib and a first coupling portion that has a greater thickness than that of the rib and that is connected to a side of the rib; a second case comprising a second coupling portion facing an upper portion of the rib and a side of the first coupling portion; a tunnel portion formed between the rib, the first coupling portion, and the second coupling portion; and a welding portion in which a boundary area of the first coupling portion and the second coupling portion is welded.