Lethalmike, thank you for your suggestion.
I do agree that it would be useful to have access to this information from the battle screen. Occasionally, the battle interface, GUI, etc. is updated and this could be a potential inclusion in the future.
For the time being, if you click on your Pokemon in the party, you can see the Pokemon's current HP there.
Thanks for your reply Pretentious.
I'm glad that you agree on this, because it would help a lot on our future battles.