Common Failures in Welding Battery Casings
When it comes to assembling power batteries, a crucial step involves welding the positive and negative pole columns to the connecting blocks through laser welding. However, this process can be prone to potential failures, with one of the most common being the formation of pores within the welds. These pores can compromise the integrity of the battery's seal.
Potential Failure: Pores
The primary cause of pore formation in these welds is related to the presence of metallurgic pores. These pores are often the result of residual impurities such as lubricants and cleaning agents on the surface of the pole columns. When subjected to the high heat generated during laser welding, these impurities vaporize rapidly, causing gas to escape into the molten pool and resulting in pore formation.
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Recommended Solutions
To address this issue, several solutions can be implemented:
1. Thorough Cleaning: Before welding, it's essential to ensure that the pole columns are thoroughly cleaned to remove any substances that could generate gas during welding. Proper cleaning procedures can significantly reduce the risk of pore formation.
2. Optimized Welding Parameters: Adjusting the welding parameters can help minimize the formation of pores. By reducing the laser power and increasing the welding speed, the pore content can be significantly reduced.
3. Use of Scanning Mirror Lasers: An alternative approach is to replace pulse laser spot welding with scanning mirror lasers. This change takes advantage of the keyhole's stirring effect on the molten pool, expelling gas more effectively and almost entirely eliminating pore formation in the weld.
Click this link for a video showing (Laser welding machine for battery pack)
In conclusion, welding the pole columns in battery assemblies can be vulnerable to pore-related failures, jeopardizing the battery's seal. However, by implementing proper cleaning procedures and optimizing welding parameters or adopting scanning mirror lasers, these common failures can be effectively mitigated, enhancing the quality and reliability of power battery assemblies used in electric vehicles and energy storage systems.