welding 18650 cells with DN-5 spot welder
- Thread starter madin88
- Start date
Allex
100 MW
I would say 750 welded cells to get the money back. If he would would offer the welding for 1USD per cell 
kenkad
100 W
madin88,
Have you considered making a pneumatic press that you could use to place slight indentations (four square) in the strip so that, when you spot weld, the tips automatically want to 'drop in' the indentations and you would have complete symmetry of all the spot welds? Maybe a indentation head made up using M2 cone point set screws. What is the typical spacing of the four weld spots that you currently do (each side of the cell is different size in the photos)?
Have you considered making a pneumatic press that you could use to place slight indentations (four square) in the strip so that, when you spot weld, the tips automatically want to 'drop in' the indentations and you would have complete symmetry of all the spot welds? Maybe a indentation head made up using M2 cone point set screws. What is the typical spacing of the four weld spots that you currently do (each side of the cell is different size in the photos)?
silentflight
100 W
Thank you maddin88!
I meant to say it would be a good idea for the chinese company that makes the DN-5 to design a new model of spot welder based on FETs. This new model would weigh so much less that it would cost at least $100 less in shipping, which would help pay for the FETs which are more expensive than a transformer.
I wish we could set up a battery building makerspace somewhere, but of course most people think working with high voltage lithium is just short of suicidal.
I meant to say it would be a good idea for the chinese company that makes the DN-5 to design a new model of spot welder based on FETs. This new model would weigh so much less that it would cost at least $100 less in shipping, which would help pay for the FETs which are more expensive than a transformer.
I wish we could set up a battery building makerspace somewhere, but of course most people think working with high voltage lithium is just short of suicidal.
katou said:
hard to say because aside from the bare cells, other materials must be calculated and also TIME needed for building one pack
the materials i use are:
different type of glue (CA, hotglue, sikaflex)
nickel or hilumin
balancing wires
main wires
connectors
different shrink tubes
edge protectors
sheets for the sides (at least on the sides where the welds are)
@ kenkad
yeah a press would be nice but by now i do not have plans to build one. its not a problem if the dots are not all identically spaced (only for the eye) but the force needed to press the tips to the cells makes the hands a bit tired after some time, so a press would be more comfortable here^^
Here is picture of strips/sheets that makita uses. http://aijaa.com/Frn35J 0.1mm thick. Left one I filed off that plating and I think its copper inside but what is that plating? These are very easy to spot weld using dn-10. I just cant find that kind of strips anywhere. I would like to use these instead of nickel or hilumin.
Electro tinned copper, looks like same? http://www.wielandsa.com/commonmedia/content/media/bildergallerie_neu/w_bereich_1/produkte_4/Ringe_verzinnt_liegend_Al_w_x_04.jpg
EDIT: I have one DN-10 for sale in Europe, PM if interested.
Electro tinned copper, looks like same? http://www.wielandsa.com/commonmedia/content/media/bildergallerie_neu/w_bereich_1/produkte_4/Ringe_verzinnt_liegend_Al_w_x_04.jpg
EDIT: I have one DN-10 for sale in Europe, PM if interested.
okashira
10 kW
anttipaa said:
Very interesting. That material would be quite useful... but where to purchase it?
Nickel plated copper would also be nice, but hard to find for cheap.
The problem with Nickel is the cost / conductivity is just not great.
Hilumin, no thanks. Steel is 1/2 the conductivity of Nickel.
okashira said:
thanks for this information. i thought its similar and i have also read it somewhere. need to check.
maybe steel-nickel alloy has better conductivity than pure steel?
so this means:
nickel = 17,5% of copper
pure steel = 10,3% of copper
madin88 said:
Pure nickel has 4.16x more electrical resistivity than copper ---- nickel = 24% electrical conductivity of copper
Steel is an alloy, so depends of the % of carbon, iron or adds it varies between 10 to 100 × 10-8 Ωm
So steel alloy would be between 6x to 60x the electrical resistivity of cooper. ---- steel alloy = 16,6% to 1.6% electrical conductivity of cooper
Common carbon steel has 9x more electrical resistivity than cooper ------ carbon steel = 11% electrical conductivity of cooper
Steel strips are tinned with nickel for avoiding corrosion so it would be slighty better conductor
okashira
10 kW
Nobuo said:
The nickel plating is ultra thin so not much help there.
Also Hilumin is not a nickel-steel alloy, it's just cheap steel with nickel plate.
Nickel-steel alloy would have even worse conductivity then cheap steel.
seems like many different values for cunductivity are prevalent here.
the best would be to measure resisistance of lets say a strip with 1m by measuring voltage drop at a given current. this would make it clear. the cross section we know.
any news about the material makita uses? is it really tinned-copper?
i will give these nickel-copper alloy strips available on amazon or ebay a try.
the best would be to measure resisistance of lets say a strip with 1m by measuring voltage drop at a given current. this would make it clear. the cross section we know.
any news about the material makita uses? is it really tinned-copper?
i will give these nickel-copper alloy strips available on amazon or ebay a try.
nieles
10 kW
welding copper strip with copper electrodes might not be a very good plan.
i have had the idea to use graphite rod as a electrode. the electrode has higher resistance than copper, but this does not matter (just keep it small)
because the graphite is very heat resistant.
http://www.ebay.nl/itm/Graphite-Quartz-Stirring-Rod-Various-Lengths-Dias-For-Melting-All-Metals-/360870428784?pt=LH_DefaultDomain_3&var=&hash=item54058dc070
not that expensive for a test.
i have had the idea to use graphite rod as a electrode. the electrode has higher resistance than copper, but this does not matter (just keep it small)
because the graphite is very heat resistant.
http://www.ebay.nl/itm/Graphite-Quartz-Stirring-Rod-Various-Lengths-Dias-For-Melting-All-Metals-/360870428784?pt=LH_DefaultDomain_3&var=&hash=item54058dc070
not that expensive for a test.
okashira
10 kW
madin88 said:
Not really. Resistivity of metals is well established.
Also, pretty sure that you will find copper-nickel alloy to be terrible.
Stick with nickel, copper or nickel plated copper, or maybe aluminum alloy.
madin88 said:
Well makita and hilti uses plated copper in powertool packs. There must be reason for that too? I have to check bosch, hitachi and dewalt. Also those plated copper strips were easier to spotweld than purenickel (with dn-10). I just dont know why?
okashira
10 kW
Yes, precisely, for a long term use, you'd really want nickel plated copper. Or at least be able to pot the area around the weld.
If you coated everything nicely with some corrosion inhibitor before wrapping / sealing a pack it would be fine.
To the guy asking about where to get cheap nickel plated copper strip, I have the same question.
Yeah, I may try that tinned copper strip. Not sure how it will weld.
If you coated everything nicely with some corrosion inhibitor before wrapping / sealing a pack it would be fine.
To the guy asking about where to get cheap nickel plated copper strip, I have the same question.
Yeah, I may try that tinned copper strip. Not sure how it will weld.
My DN10 arrived through the week. This morning forum member RideTheLightning came by and we did some testing.
The nickel strip was just 0.12mm. The welder has somewhat limited fine adjustment, and as such we were finding that with strip that thin, it was either blow a hole in it - or not stick it with sufficient strength. Thicker material is definitely going to be easier - will get some 0.3mm strip or thicker. You can also notice the amount of heat produced in that short burst - as it chars the wood significantly.
Volume knob was turned to 1 - any less and it would not stick it, any more and it would blow a hole. We also filed the tips a bit to increase surface contact - which did help. Keeping the tips clean is essential. The strip was sticking to the electrodes - and made a mess.
Would be good to be able to fine tune it - very touchy at the moment.
[youtube]PI32jSGLKho[/youtube]
...some more testing required.
The nickel strip was just 0.12mm. The welder has somewhat limited fine adjustment, and as such we were finding that with strip that thin, it was either blow a hole in it - or not stick it with sufficient strength. Thicker material is definitely going to be easier - will get some 0.3mm strip or thicker. You can also notice the amount of heat produced in that short burst - as it chars the wood significantly.
Volume knob was turned to 1 - any less and it would not stick it, any more and it would blow a hole. We also filed the tips a bit to increase surface contact - which did help. Keeping the tips clean is essential. The strip was sticking to the electrodes - and made a mess.
Would be good to be able to fine tune it - very touchy at the moment.
[youtube]PI32jSGLKho[/youtube]
...some more testing required.
