How Can Ultrasonic Welding Overcome The Challenge Of Incomplete Bonding With Short Pressure, Foil Damage With Long Pressure in Aluminium-Copper Foil Lamination?

For welding aluminium and copper, which have high thermal conductivity, the most suitable process is ultrasonic metal welding. This is a low-temperature bonding process where atoms interact by removing and dispersing oxides and contaminants.

It is particularly effective for aluminium, a material often difficult to resistance weld, as it efficiently removes the robust oxide layer on its surface. Furthermore, compared to the precise design of the welding horn, the process offers the benefits of a large joint area and suppressed contact resistance.

The current collector is manufactured by laminating 50 or more metal foils, each with a thickness of 10–17μm. Each individual layer is extremely thin and prone to damage, requiring special care during welding.

There are two main challenges in the welding process:
1. If the pressure time is shortened to avoid damaging the metal foils, it may not be possible to achieve a complete weld across all the laminated layers.
2. If the pressure time is too long, the metal foils can become excessively deformed and damaged.
Therefore, achieving an optimal pressure time is critical for a successful weld.