Laser Welding Battery Module Housing Microstructure Control
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Solution Overview
Problem
The existing methods for manufacturing battery modules face challenges in enhancing the mechanical properties of welding joints due to surface defects such as holes, craters, and burrs, which can lead to leakage and fatigue damage, especially under external shocks and repeated loading during charging and discharging.
Innovation Solution
A method involving the use of laser irradiation to form a welding joint with distinct microstructures by differentiating the thermal history between the bonding region and the surface region, where the surface region is re-melted and solidified to cover the bonding region, reducing surface defects and improving mechanical properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If welding is performed to join housing members to form a sealed internal accommodating space, then the housing structure is formed and sealed, but surface defects such as holes, craters, and burrs are generated during the welding process, reducing mechanical properties of the welded portion
Solution Approach 1:
The patent applies laser irradiation to change the thermal parameters of the welded portion, creating distinct thermal histories between the bonding region and surface region. This parameter change transforms the microstructure by controlling melting and solidification processes, thereby improving surface quality and mechanical properties while maintaining the sealed structure
Solution Approach 2:
The patent utilizes phase transitions (melting and solidification) through controlled laser irradiation. The bonding region undergoes melting and solidification to form a strong joint, while the surface region is selectively re-melted and solidified to eliminate surface defects. This controlled phase transition improves both the sealing integrity and surface quality
2Strength
If conventional welding is used to join housing members, then the housing structure is formed, but the connection portion has low resistance to external shock and may be easily damaged
Solution Approach 1:
The patent changes the thermal parameters during welding by applying laser irradiation with controlled energy distribution. This creates a refined microstructure in both the bonding and surface regions, enhancing the mechanical strength and shock resistance of the connection portion. The controlled thermal history improves the reliability of the welded joint under external shocks
Solution Approach 2:
The patent creates a composite microstructure within the welded portion, with distinct bonding region and surface region having different microstructural characteristics. This composite structure combines the strength benefits of melted-and-solidified bonding with the defect-free surface quality, resulting in improved overall reliability and shock resistance
3Manufacturing precision
If surface defects are removed by physically working welded portions, then surface quality is improved, but the manufacturing process becomes more complex and time-consuming
Solution Approach 1:
The patent replaces mechanical surface treatment methods with laser irradiation. Instead of physically working the welded portions to remove surface defects, the laser energy selectively re-melts and solidifies the surface region, eliminating defects through controlled phase transition. This substitution simplifies the manufacturing process while improving surface quality
Solution Approach 2:
The patent uses laser irradiation to change the thermal parameters of the welded portion surface, transforming the microstructure in-situ. This parameter change approach eliminates the need for separate mechanical finishing operations, reducing process complexity while achieving superior surface quality and defect removal
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 approach results in a battery module with improved mechanical properties and reduced risk of surface defects, enhancing both the aesthetic finish and resistance to impurity-induced defects, thereby ensuring the integrity of the welding joint.
Implementation Method 1
forming a welded bead in which a first alloy of the first base material and a second alloy of the second base material are melted and solidified by irradiating the contact surface between the first base material and the second base material with a laser for welding
Implementation Method 2
re-melting and solidifying a surface of the welded bead by irradiating the welded bead with a laser for surface treatment to form a welding joint portion including a bonding region which is not re-melted in the welded bead and a surface region covering the bonding region and having a microstructure different from that of the bonding region due to the re-melting and solidification
Data Source
Figure 1~2
Figure 3A~3B
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AI summary
Provided is a method of manufacturing a battery module including a) aligning a first base material and a second base material, which are welding objects and housing members that are combined with each other to form an internal accommodating space in which a plurality of battery cells are accommodated and b) forming a welding joint portion including a bonding region and a surface region covering the bonding region by irradiating a contact surface between the first base material and the second base material with a laser, the bonding region and the surface region forming the welding joint portion having different microstructures due to different thermal history.