Here is a decent battery overview and about the safest way you could build a battery pack.
Still pretty high chance of a short which will cause a fire and noxious smoke.
The other option is look for an existing LiPo pack from the RC Car world. 3S has 11.1 volts and 4S has 14.8 volts, 6S has 22.2 volts. Putting batteries in series increases voltage additively but not amp hours (watts are amps x voltage, so a 10000 mah 6S battery at 22.2 volts would be 222 watt hours, a battery that costs around $120.00). Two 6S batteries in series would provide 44.4 volts at 222 watt hours. Putting batteries in parallel increases amp hours but not voltage. Two 222 watt hour 6S batteries in parallel would give 22.2 volts at 444 watt hours. Would take quite a bit of research to work out what would be needed for your motor and it very likely could damage your motor and likely void your warranty. So 4 6S 10000mah batteries at $120.00 each, 2 sets of 2 batteries in series that are then connected in parallel will give you 44.4 volts and 444 watt hours for $480 dollars as a comparison.
You can search LiPo packs under the "S" voltage you want, just remember if you overcharge or discharge to fast, they will catch on fire, explode, emit toxic fumes, so not to be monkeyed without doing the research, having the right tools for the job, and working in a safe area.
You would also need a good balanced charger will cost a couple of hundred bucks.
You would also need the right connector and a container/package to hold the batteries.
Here is what happens when Lipos go boom. Fast forward to 1 min 20 seconds...