My 1st generation ipod battery problem

My 1st generation ipod is stuck on a red battery sign with a lightning bolt underneath. Every time i unplug it, i shuts off. When it is plugged in, it is unresponsive! I tried the DFU mode n i restored it but it still would not work. BUT, At one point the ipod did turn on and was completely responsive. then a few minutes later, it went right back to the red battery sign with the lightning bolt underneath and is completely UNRESPONSIVE...What Do I Do!!! PLZ HELP!!!!!!