Friction stir welding, instead of spot-welding

Hi guys, yesterday, I disassembled a power tool battery pack and what a surprise, all the welds were friction stir welds, at least this is what it looks like to me.

Please check the picture and tell me if I'm totally wrong about this.




Can anyone give more information on the topic, how they do this? What about the heat... is it less than the spot welding heat? Or not really?

Thank you for all the info you can share....

Maybe laser welded?

FSW would be give a higher quality connection but I'm not sure it's suitable for welding TO the battery because the total heat input is [seems like, idk] higher even though the active area doesn't get as hot.

Regardless of how it's actually been welded, that tab is slotted for the purpose of electrical resistance welding.

Indeed correct observation..

Anyone.. ideas, what kind of weld is this?

you are correct, those are "friction stir welds" but they take a lot of time to "weld", cause a lot of heat and can also puncture the cells in the bottom. Also machines ar more likely to be in the $10000 range or more. Looks good but has no application in battery manufacturing, at least not with cylindrical cells.

The Battery Doctor said:

you are correct, those are "friction stir welds" ..........

Click to expand...

What evidence is there to confirm that ?
They dont look any different to most any other "spot" weld or ultrasonic weld.
...so what makes you so sure !

The Battery Doctor said:

Looks good but has no application in battery manufacturing, at least not with cylindrical cells.

Click to expand...

Your post is self-contradictory.

If it didn't, then why would they be used on the power tool packs pictured in the OP?

If they weren't used on them, then why are you claiming they were?

If they were used on them, then why would you claim it has no application in battery manufacturing, at least not with cylindrical cells, when the packs pictured in the OP *ARE* batteries, and they *ARE* cylindrical cells?


Based on this and other posts you've made in your flurry since joining, I wonder how much knowledge you're contributing, vs how much SEO spam for your business that you're leaving via your signature/profile?

Those joints look nice, any chance you can peel up a button and photo however it looks?