why my x220 doesn't work without AC plugging in?

I am back and coming with another issue.
Well, my battery doesn't work any more. I need to plug in the AC to turn on my x220

Does anyone know what happened?
The battery can be recognized, it's fully charged, but without the AC plugging in....then it's dead!
T___T
I left it home today and put it in my closet with sleeve on......
It should be safe....

Thanks, guys!

 

I suspect a hardware problem. The battery has several contacts so it would be possible for the computer to read the charge state through the appropriate contacts but there's a problem in a system which takes the power out of the battery and converts it to the various voltages used by the notebook hardware. Obviously, if no power is getting through then the notebook can't start on battery.

You can visually inspect the battery connectors, both on the battery and on the computer to see if there is any obvious problem. Otherwise it's over to Lenovo to fix.

John

 

Really?
I am gonna check this afternoon.
If you have read my other thread, you would know that a kid shaked it down and knelt on it. But it worked through the battery after that accident; just one day after, it's not working. But I haven't used it a lot after the "fell down and knelt on", just like one hour in total. So, I don't know if there is a connection.
Anyway, thanks. But I just hope it will work later today .....