Power batteries and energy storage batteries are the two major scenarios for the application of battery technology, with energy storage batteries corresponding to solar energy and other devices, and power batteries corresponding to new energy vehicles. Power battery packages are categorized into three main forms: cylindrical, square and soft pack. The soft pack batteries have been used as the industry's first choice for mobile devices, but in automotive applications, but also because of its volume of controllability is also valued by automotive brands, especially for plug-in hybrids, taking into account the layout and weight of the entire vehicle, the soft pack battery volume advantage is more obvious, today, follow the Shangtuo laser editorial to talk about the soft pack battery laser welding.
By virtue of its concentrated energy, high welding efficiency, high processing precision, weld depth to width ratio and other advantages, the laser has become a power battery copper-aluminum welding, and even the only technology that can be electroplated nickel welded to copper materials. Reasonable selection of welding methods and processes will directly affect the cost, quality, safety and consistency of the battery.
Dissimilar material welding for soft pack battery
For the heterogeneous material welding of soft pack battery, it mainly includes positive and negative lugs in series, positive and negative lugs welded with copper sinks, and multi-layer negative aluminum and copper sinks welded. The thickness of copper lugs is generally 0.2-0.5mm, and the thickness of aluminum lugs is generally 0.2-0.6mm.
Soft pack battery laser welding copper-aluminum material welding the biggest difficulties
Due to the large difference between the melting point of copper and aluminum, in the liquid state of each other unlimited mutual solubility, solid state, limited mutual solubility, can form a variety of intermetallic compounds as the basis of the solid solution phase, so the welding should try to choose the beam quality of the light source, reduce the heat input, shorten the time of contact between the copper and the liquid aluminum phase, in order to reduce the formation of the two intermetallic compounds to enhance the strength of the welded joints.
Difficulties of the laser welding process
High reflectivity/thermal conductivity materials - require high laser power densities, high welding reflectivity, and high requirements for laser stability and reliability;
Carbon content of high materials - carbon content > 0.77%, due to the fast cooling and heating characteristics of the laser, it is very easy to produce cracks in the center of the weld and the heat-affected zone (cold cracks); containing low boiling point elements - such as materials containing elements such as Mg, Zn, etc., due to the low ionization energy of such Elements of the ionization energy is low, a large number of evaporation in the laser welding process, and even continue to absorb the ability to become plasma, will change the weld at the microstructure type and chemical composition, seriously deteriorate the performance of the weld.
Related Products:
ODVS05 Series Scanners
