Hi,
Try Removing your battery first then unplug the Power adaptor from the system, then press and hold down the power button to do a power drain on your systems motherboard.
return your battery then try powering the system using battery only.
if the system still wont power up using battery, plug in your adaptor go in windows, go to add remove programs or programs and features depending on what windows your system has, once in either one of the two look for energy management uninstall it from your system then restart the computer one last time try powering using your battery only.
If still this does not work powering the system using battery try updating drivers for your motherboard go to the lenovo website
consumersupport.lenovo.com for the chipset drivers download
if still nothing has changed call lenovo probably something is wrong with your motherboard or battery you may need to send the system back to lenovo for further checking.