Patent ID: 8125191

Claim:
An early warning method for an abnormal state of a lithium battery, applicable to a portable electronic device having the lithium battery, comprising: obtaining at least one curve of voltage against electric quantity by the portable electronic device, the portable electronic device saving the curve of voltage against electric quantity in a memory of the portable electronic device, the curve of voltage against electric quantity corresponding to a predicted average current consumption when the lithium battery is at an operating test state; obtaining an operating average current consumption, and an operating electric quantity from a first voltage to a second voltage by the portable electronic device when the lithium battery is at an operating state; the portable electronic device finding the predicted average current consumption, finding the curve of voltage against electric quantity which is against the operating average current consumption through the memory, according to the operating average current consumption, and retrieving a warning electric quantity from the curve of voltage against electric quantity in accordance with the predicted average current consumption in a range from the first voltage to the second voltage; and determining whether the operating electric quantity is greater than the warning electric quantity by the portable electronic device, so as to perform the early warning of the abnormal state of the lithium battery.