Making large packs from small cells is the expensive way to build a
battery pack. However, you get a _lot_ of performance from smaller
cylindrical cells. That is why people do it.
It is best if the cells are at approximately the same SOC when you
weld them together, but they don't have to be.
A new cell welder costs ~ $15,000 or more. If you know the parts you
are looking for, you can get something on Ebay for $3500, maybe less
if you are patient and hunt around. (The $175 Harbor Freight spot
welder will not do. You need an entirely different welder.) You need
a double pulse inverter welder capable of 4000 amps. You need a "fine
spot" dual welding head.
You can see the welder in action at:
http://www.youtube.com/watch?v=tQkf7jN2D1g
Bill D.
At 11:50 AM 9/3/2013, you wrote:
If I am going to go with a spot welded pack what battery has a
proven track record? Are they affordable? People used to talk about
1 dollar batteries. Do these exist? When buying a thousand
batteries what kind of a deal can you get? Once you make a module
these batteries are literately joined at the hip. Now one charger
in effect is needed per module. I love the concept. Bill Dube does
this. Can mere mortals do it? Will a 175 dollar Harbor Freight
spot welder hold up after thousands of spot welds. Lawrence Rhodes...
_______________________________________________
UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub
http://lists.evdl.org/listinfo.cgi/ev-evdl.org
For EV drag racing discussion, please use NEDRA
(http://groups.yahoo.com/group/NEDRA)
