To make sure that it is an issue with the battery itself disconnect the charger from both ends and then reconnect.
If that still does not work try a different charger to determine if it was a problem with the charger.
Hold the power button for 10 seconds to see if device will reset
Once you have determined that the charger is not the problem and that the device has a faulty battery, it is time to replace the battery to restore your device.
The SoundLink micro uses a lithium ion battery and you can find this battery on the website where you purchased the speaker.
First you must acquire the proper tools, such as a screwdriver, knife, lithium ion battery, and a needle.
Open the device and remove the damaged battery. Then replace the damaged battery with the new one.
Once completed put the speaker back together and charge the SoundLink micro.
After charging the battery the speaker should function like normal.