Why did my Lenovo battery die ?

Let's begin with introducing the detailed battery information of LENOVO B50

· Battery rating: 14.4V
· Battery capacity: 2200mAh (32Wh)
· Type: rechargeable Li-ion original battery
· Battery color: Black

We all know that laptop batteries typically have a lifespan of 2-3 years or 300-500 cycles, but may last as little as 12-18 months .

The main enemies of battery longevity are age, the number of charge cycles, amount of time at full charge, and high temperature. If used only on main power,  fully charged, in a hot environment, longevity is reduced.

For tips on how to increase battery lifespan, see "How can I increase battery life?".

If the battery status indicator appears to be incorrect, it is recommended that you perform a reset.  To reset the battery gauge in the Power Manager, click on Battery Maintenance then Perform Reset. This will require you to let your battery run completely down, and then to recharge it fully. Should your battery appear to indicate the incorrect status after a reset, and you believe there may be a problem with it,

But why did my battery SUDDENLY die?

The lithium-ion battery packs used in ThinkPads are intelligent batteries. They contain a microprocessor to monitor the state of battery. Information about remaining battery capacity is passed to the system from the battery pack. If the power management system determines that the battery can no longer supply reliable or safe power, it will indicate that the battery needs replacement.

Source:forums.lenovo.com