Windows 7 hibernates by itself

I have Windows 7 Pro 64-bit installed on a Lenovo Thinkpad X120e, and it is set up so that it will go into hibernation when the battery is too low. Sometimes, the computer hibernates by itself, and when I boot it again it tells me that it hibernated because of low battery. The problem is, the battery is not low or damaged or anything. What can be the problem?

In my experience this type of issue is caused by either the battery (usually) or laptop (rarely) reporting that the battery capacity is 0% for just a second. The problem may happen most often when you disconnect the power and the battery changes from charge to discharge.

The problem is that the chip in the battery is reporting the current capacity incorrectly, and the system interprets it as 0% which triggers low battery actions. Chemically, the battery itself is fine, but the internal electronics are malfunctioning. In almost every case I've seen this issue occur, it was corrected by replacing the battery. If you're using a third party battery or refurbished battery, this type of issue is more common.