Anyone has any experience with aluminum spot welding

Anyone has any experience with aluminum spot welding

I have 21700 batteries with an aluminum cover (positive pole / plus).
They have to be welded.


Now the question is can I weld the wire with securing wire (normal metal) or with an aluminum wire.
And if so which devices work and has someone already done it and can give me tips.

(In any case, soldering is not possible because aluminum does not accept solder, I still tested it, but I tested it again.

I have a special solder for aluminium; it kind of works, but it is merely a "glue". I am sorry, I have no make-info but something like this does exist

I'm not sure but suspect you would have to lightly sand each aluminium surface before trying to spot weld to remove the oxide layer aluminium makes with air or any anodizing layer, etc.
Aluminium is also a better conductor of both heat & electricity than say equivalent nickel strips, so spot weld currents would probably need to be a fair bit higher.

I have successfully soldered aluminum using the special solder and flux . The joint worked well until the cycle stress of the battery
(600 amp ) worked its way lose . This joint required a 300 watt iron . This way has very low cohesive bonding .

Using a ultrasonic welder is the way to go , It vibrates the joint to melting point or bonding point in very little time . The nice thing
about U welding is the the over all heat required is very little and can do different metals , like aluminum to copper.

This is the professionals use to the aluminum tabs to get a proper joint. Unfortunately is not cheap to buy .

JimJr. said:

I have successfully soldered aluminum using the special solder and flux . The joint worked well until the cycle stress of the battery
(600 amp ) worked its way lose . This joint required a 300 watt iron . This way has very low cohesive bonding .

Click to expand...

What means did you take?
Can you link them.
Thank you

Walde said:

JimJr. said:

I have successfully soldered aluminum using the special solder and flux . The joint worked well until the cycle stress of the battery
(600 amp ) worked its way lose . This joint required a 300 watt iron . This way has very low cohesive bonding .

Click to expand...

What means did you take?
Can you link them.
Thank you

Click to expand...

I used "scotch bright " to polish the aluminum oxide off and applied the flux ,then the heat , and the solder and waited for it to flow. Aluminum oxide is a translucent brown in color and can not be seen with the eye when it is a few molecules thick and is chemical,water,abrasion, temperature resistant .

Be sure to wipe off excess flux when done it is corrosive. Do not forget to cool off the the solder job when you are done to save the seals

I did aluminum to aluminum and aluminum to copper. I used https://www.ebay.com/itm/ALUMINUM-S...jMAAOSw~gRV07gW:sc:USPSFirstClass!44460!US!-1 or similar.

My solder joints lasted about a year and a half

I resorted to a mechanical connection for longer connection life

Jimjr