I have seen it all lol.

Found this reference on a search of the chemical composition of urine:

"Urine contains 95% water and 5% solids.  More than 1000 different
mineral salts and compounds are estimated to be in urine.  So far, our
scientific community knows of about 200 elements.  Some substances are: 
vitamins, amino acids, antibodies, enzymes, hormones, antigens, interleukins,
proteins, immunoglobulins, gastric secretory depressants, tolergens,
immunogens, uric acid, urea, proteoses, directin, H-11 (a growth inhibitory
factor in human cancer), and urokinase.  Believe it or not, scientists have
know for years that urine is antibacterial, anti-protozoal, anti-fungal, anti-
viral, and anti-tuberculostatic! "

So what is required for a good electrolyte material in a fuel cell? I have no idea; but if you can find a cheap material to go inside of a type of fuel cell, then you will have solved the biggest barrier to using a fuel cell: COST!!

Unfortunately this urine battery just only uses a copper
and a magnesium plate as electrodes and these plates
are consumed.
The urine is just the electrolyte in it and you can also
use saltwater for this purpose, so it is not really powered
by urine, but by copper and magnesium...

So this is not a real urine battery, where only the urine
would be consumed... so this is just vapourware...
unfortunately...
Until a battery comes out, that will only consume the urine
and not the electrodes, then this will be much more interesting !