Laser Welding vs. Ultrasonic Welding for Busbars
Introduction
If you’re assembling battery busbars for EVs, drones, or energy storage systems, you’ve likely asked: Should I use laser welding or ultrasonic welding?
Both techniques join copper, nickel, or aluminum busbars but differ in heat, precision, and joint strength. This article compares laser vs. ultrasonic welding from an engineering perspective—helping you choose the right method for your lithium battery packs. Wellgo Battery, a trusted busbar manufacturer, uses both technologies to ensure high-precision, safe, and durable electrical connections.
Overview: Why Busbar Welding Matters
A busbar welding process determines how effectively current flows between cells. A poor weld increases resistance, heat, and potential safety risks.
According to IEEE Transactions on Components and Packaging Technologies, optimized welding can reduce electrical loss by up to 12% in lithium battery busbars (IEEE Xplore).
Wellgo Battery employs automated welding systems that maintain low resistance and consistent bonding—ensuring high reliability in energy-dense EV packs.
What Is Laser Welding?
Laser welding uses a focused laser beam to melt and fuse metals precisely. It’s ideal for copper and nickel busbars where tight tolerances are needed.
● Key benefits include:Minimal heat-affected zone (HAZ)
● High precision and repeatability
● Suitable for multi-layer or dissimilar metal joints
Wellgo Battery integrates fiber laser welding into its custom copper-nickel busbars, offering exceptional strength and conductivity for high-power lithium battery systems.
What Is Ultrasonic Welding?
Ultrasonic welding joins metals through high-frequency mechanical vibrations under pressure—without melting the material. It’s perfect for thin aluminum and nickel busbars where overheating must be avoided.
● Benefits include:No external heat input
● Clean, oxide-free joint surfaces
● Energy-efficient and fast
According to Journal of Manufacturing Processes, ultrasonic welding achieves excellent bonding strength for thin conductive layers (Journal of Manufacturing Processes | ScienceDirect.com by Elsevier).
Wellgo Battery uses ultrasonic welding for lightweight and compact battery busbar assemblies in EV and drone applications.
Key Differences Between Laser and Ultrasonic Welding
|
Feature |
Laser Welding |
Ultrasonic Welding |
|
Process Type |
Fusion (melts metal) |
Solid-state (no melting) |
|
Heat Input |
High (localized) |
Low |
|
Suitable Materials |
Copper, Nickel, Steel |
Aluminum, Nickel |
|
Precision |
Very high |
Moderate |
|
Cycle Time |
Fast (automated) |
Fast (limited thickness) |
|
Maintenance |
Medium |
Low |
|
Best For |
High-power EV packs |
Lightweight modules or thin tabs |
Wellgo Battery provides both laser-welded and ultrasonic-welded busbar designs, selecting the method based on current density, material type, and project requirements.
Performance Comparison: Strength & Conductivity
Weld strength and electrical resistance are crucial to battery safety.
Studies show laser welding joints can achieve up to 90% of base metal strength, while ultrasonic welds excel at maintaining low resistance for thin foils.
Source: Journal of Materials Processing Technology (Journal of Materials Processing Technology | ScienceDirect.com by Elsevier)
Wellgo Battery’s busbars are tested for tensile strength, resistance drop, and thermal cycling to ensure consistent performance under dynamic load conditions.
Thermal Management & Safety Considerations
Laser welding generates localized heat that must be controlled to prevent damaging nearby cells. Ultrasonic welding, meanwhile, produces frictional heat but avoids metal melting.
In high-energy EV packs, improper heat management can cause hot spots or seal failures.Wellgo Battery applies thermal simulation and precision jig design to minimize heat-affected zones and ensure safe operation in lithium-ion battery modules.
Cost, Automation & Production Efficiency
Laser welding systems are more expensive to install but allow full automation and tighter quality control. Ultrasonic systems are cheaper and ideal for smaller-scale or thin-foil manufacturing.
As production scales, automation and speed become decisive factors.Wellgo Battery optimizes both welding methods to reduce production costs, delivering mass-manufacturable busbar solutions that meet ISO and automotive standards.
Environmental & Regulatory Compliance
Modern manufacturing requires eco-friendly processes and traceable materials.
Both laser and ultrasonic welding comply with EU Battery Regulation (2023/1542) and UL 1973 safety guidelines when executed with precision (Batteries - Environment - European Commission).
Wellgo Battery ensures its battery busbars meet RoHS, REACH, and ISO 9001 certifications, using recyclable copper and aluminum materials.
Summary: Choosing the Right Welding Technique
|
Factor |
Best Option |
Why |
|
Copper or thick busbars |
Laser welding |
Strong fusion and deep penetration |
|
Aluminum or thin layers |
Ultrasonic welding |
Minimal heat and clean joints |
|
High-volume automation |
Laser welding |
Better process control |
|
Low-cost assembly |
Ultrasonic welding |
Less setup complexity |
|
Multi-metal connections |
Laser welding (Cu-Ni) |
More adaptable for hybrid designs |
Wellgo Battery helps customers evaluate both methods, offering custom busbar designs optimized for your material mix, current load, and manufacturing scale.
