Not an expert here as far as building from scratch, Dr. Bass would be best for that. From what I can see, there are some truth and misconceptions in most of the above posts.
Hopefully I will not ad to the misconceptions. There are two things going on as far as connections. Series ( negative to positive, like in a flashlight MORE work done, short time ).
Parallel ( negative to negative Positive to Positive, same work done, for longer period of time ). To get battery packs you add cells together in series AND parallel to achieve
the Voltage / Amperage you seek. Here is a link to a post from MostlyBonkers from this time last year. Probably explains better than I could
http://electricmotorcycleforum.com/boards/index.php?topic=4280.0Now, to figure out what you want to do.
A DC motor spins faster as more voltage is added, 96 Volts faster than 72, 108 faster than 96, etc.
If you have access to dozens or hundreds of these pouches, then, knock yourself out, have fun. DR. Bass seems to enjoy himself.
If not, it is probably faster and cheaper to buy an assembled pack with BMS already installed in the Voltage and Amperage that you seek.
Here is a company that has been around a few years. I have not used the product, and do not endorse, just one option to view.
http://elitepowersolutions.com/products/product_info.php?cPath=27_38&products_id=186Consider that you will need a couple dozen cells, BMS, charger, plus your time. Compare to turn key solution.
Let the stone throwing begin.