Method for detecting critical failure of battery

The invention discloses a method for detecting critical failure of a battery. The method is that the critical failure condition of an UPS battery is determined by analyzing the time from inverting discharging to reach the voltage critical determining value of the UPS battery. The method is simple to perform; the detection cost can be effectively reduced; in addition, the failure condition of the UPS battery can be accurately detected; an LED of the UPS can be used for reminding, thus a user can timely conveniently know the failure condition of the UPS battery, and as a result, the accident caused by the failure of the UPS battery can be greatly reduced. The method can be widely applied to the field of detection of batteries.