Ultrasonic spot welding machine for battery tabs lithium-ion batteries
Two metals joined without melting. The horn presses onto the tab and the terminal and vibrates, the oxide between them breaks up, and the two surfaces bond in well under a second — no filler, no flux, no spatter, and no heat travelling down into the cell behind the joint.
The metal is scrubbed together, not melted
The horn is pressed onto the top part with a set force and set vibrating at ultrasonic frequency. Both parts stay solid the whole time. What happens between them is friction: the oxide skin on each surface breaks up, the surface peaks interlock and the two metals weld to each other. The heat is generated only at the interface — across a few tens of microns — not through the part.
That is what makes it useful on a battery line. A resistance spot weld or a laser weld melts a pool of metal into the joint, and the heat behind that pool spreads into whatever is underneath. Here the bulk of the tab and the terminal stay far below their melting points, so a tab can be welded onto a cell, or onto a stack of foils, while the separator and the electrolyte behind it stay untouched.
It also removes the matching requirement. Copper to aluminium, nickel-plated copper, brass, nickel, and stacks of thin foil — combinations that are awkward or impossible to fuse can be ultrasonically welded, because nothing has to reach a shared melting range.
A press, a tuned stack, and a fixture that holds the part
Four things decide how the machine behaves. The press: a pneumatic cylinder that brings the horn down and holds a set force, from a light touch on thin foil up to 8000 N on a heavy busbar. The stack: converter, booster and horn, matched and tuned as one unit at the working frequency. The fixture: an anvil and a nest that hold the tab and the terminal in register for the fraction of a second the weld takes. The generator: the box that drives the stack and holds the recipe.
The fixture is where most of the work goes. If a tab does not sit flat, and in the same place on every cycle, the weld moves with it. Nests are machined around your actual part — send the tab and the terminal, or a drawing, and the horn tip pattern and the nest are made to suit.
Cell tabs, foil stacks and pack cables
The same head and the same press do all of it — what changes with the part is the horn tip and the nest. That is the whole tooling list.
Every job is proved on your own parts before you commit to a machine. Send a tab and a terminal — or simply the two materials and the weld area you need — and we run them, then come back with the parameters, the nugget size and a peel test result. Ask for a free process test.
Machine data
Ultrasonic battery tabs welding machine — specification
| Item | Data |
|---|---|
| Product name | Ultrasonic Battery Tabs Welding Machine |
| Frequency | 15 kHz – 40 kHz, optional |
| Power | 800 W – 12 000 W, optional |
| Voltage | 220 V / 380 V |
| Working stroke | 30 mm / 50 mm |
| Drive mode | Pneumatic |
| Maximum output pressure | 8000 N |
| Air pressure | 0.2 MPa – 0.7 MPa |
| Pneumatic components | AIRTAC / FESTO |
| Dimensions | 600 × 325 × 560 mm |
| Weight | 120 kg |
At a glance
One press and one stack cover the range — the frequency, the power and the tooling are chosen for the part, not the other way round.
Where a cold weld pays for itself
Anywhere two pieces of metal have to be joined and something heat-sensitive sits behind the joint, this is the process to look at first.
EV and e-bike packs
Module interconnects, busbars and the tab-to-busbar links inside the pack, welded without heat reaching the cells.
Cylindrical cells
Cell tabs to nickel-plated copper busbars and connection plates, welded at production rate and repeated weld to weld.
Prismatic and pouch cells
Terminal-to-tab joints and multi-layer foil stacks, in copper or aluminium, welded flat enough to sit under the lid.
Energy storage and supercapacitors
Module and rack interconnects, flexible busbars and current collectors in stationary storage systems.
Cable and terminal
HV harness, ring terminals and lugs onto stranded copper, welded without melting the strands or the insulation behind them.
Dissimilar metals
Copper to aluminium and other pairs a fusion weld cannot make reliably — joined without a brittle bimetallic melt zone.
Battery work is judged on the joint, not on the machine. A weld is set by three numbers — amplitude, force and weld time — and once they are fixed the joint repeats: same nugget area, same pull strength, same resistance. Change the part and the recipe changes with it, saved under its own number on the panel.
Every new part is proved the same way. Weld samples, pull them apart, and look at where they fail. If the tear runs through the material beside the weld rather than through the weld itself, the joint is stronger than the metal around it — which is the result to aim for.
See the full battery and electrical application page for more of the work this process does.
Ultrasonic against the two alternatives
| Resistance spot welding | Laser welding | Ultrasonic welding | |
|---|---|---|---|
| Heat into the part | A melt pool, with the heat sinking into whatever is behind it | A melt pool, plus a keyhole and spatter | Interface only — the bulk of the part stays cool |
| Copper to aluminium | Poor — brittle intermetallics form in the melt | Difficult — needs a filler and close control | Straightforward — nothing has to reach a shared melting range |
| Thin foil and stacks | Burns through, or sticks to the electrode | Very sensitive to fit-up and surface | Dozens of layers welded in one bite |
| Consumables | Electrodes to dress and replace | Shielding gas, and optics to keep clean | None — the horn and the anvil are the tooling |
| Finishing after the weld | Electrode marks and spatter to clean | Spatter and discolouration around the seam | A flat, clean nugget — nothing to clean up |
| Joint resistance | Rises as the nugget ages and oxides | Good, if the process stays in control | Low and stable, with no cast structure in the joint |
From the crate to the first good weld in four steps
Position and connect
The machine goes on a bench or into a workstation frame. Air line at 0.2–0.7 MPa, and 220 V single-phase or 380 V three-phase.
Fit the tooling
Horn with the tip pattern for your weld area, and the anvil nest that holds the tab and the terminal in register.
Set the recipe
Amplitude, force, weld time and hold time. Save it under the part number, so the next run comes back to the same four numbers.
Prove the joint
Weld samples and pull them apart. When the tear runs beside the weld instead of through it, lock the recipe and run the batch.
Not sure the joint will hold on your material? Send us the tab and the terminal and we run them here, then come back with the tooling, the parameters and a sample of the weld, before you place the order. Ask for a free process test.
Other metal welding equipment
Questions buyers ask before ordering
Can it weld copper to aluminium?
Yes. Ultrasonic welding joins dissimilar metals without forming a large melt zone, which is why it is used for copper-to-aluminium tabs and busbars. Send the two materials and we will confirm with a peel test.
How many foil layers can one weld take?
It depends on the total thickness rather than the count, and on the horn tip area you have room for. Multi-layer copper and aluminium stacks for pouch cells and current collectors are routine work for this process.
Will the weld damage the cell?
The joint is made at the interface only. The bulk of the tab and the terminal stay far below their melting point, so there is no heat path down into the separator or the electrolyte. Weld parameters are set to keep it that way.
How do I check weld quality in production?
Set amplitude, force and weld time and the joint repeats, so a periodic peel or pull test on samples tracks the process. Where the generator logs the cycle, the weld data can be monitored part by part.
Can the machine be built into an automated line?
Yes. The head, press and fixture are the working parts — the generator can be mounted separately, and the press is triggered by an external signal so a robot or an indexer can present the parts.
What support comes with the machine?
Tooling made for your part, commissioning with your material, operator training, a one-year complete warranty and lifetime maintenance support.
Send us the tab and the terminal
Tell us the two metals, the weld area you need and what sits behind the joint. We will come back with the tooling, the parameters and a welded sample — proved on your own parts before you order.
Request a Quotation