Not here to defend UPP. That U004/U005 was a safety hazard with its glued cell construction. If you read the Amazon reviews, a common complaint was the weight ripping off the frame straps on the battery bag, You drop a battery that heavy, it's bound to catch on fire later.
But someone asked about their other batteries. This is a Halilobng 48V10AH I purchased in 2021. I might have opend it anyway, but I had to do so the frist day I used it. The BMS harness was not fully plugged in, and the battery would shut off on bumps, I did correct that.. So here's the insides.
1. The cells are in a plastic form. Paper washers added over the positive ends of each cell. Spot welds appear to be done by hand. I suspect the metal forms are nickel plated steel, rather than pure nickel.
2. The cells are generic Chinese 2500 mah. FST-18650-2500. Google them and they are 10A cells, and sell for $1,50 each on alibaba, UPP surely gets them for less.
3. View of the battery, The cell assembly was not shrink wrapped, but this Hailong-2 case is so tight, I think there isn't room. Picture is blurry, sorry.
This particular battery was purchased August 2021. Still in use on my bafang front drive bike. It's rated 48V10AH. Two static tests where I discharged it from 54.6V to 40V @3 amps gave 10,6AH and 10,3AH, which seemed high. It got about 8.3AH out of it running the battery flat while riding.