Electrically-driven tool and method for an electrically-driven tool to detect battery decline

A method adapted for an electrically-driven tool to detect battery decline, the electrically-driven tool including a battery to supply electric energy, a kinetic device to receive and convert the electric energy into kinetic energy, and a controller, said method being implemented by the controller and comprising steps of:

• A) pre-storing a dataset of energy provision time that includes at least one data piece of energy provision time, one of the at least one data piece signifying a predetermined time length presumed to be required by the battery to provide a predetermined amount of electric energy;
• B) providing the predetermined amount of electric energy to the kinetic device to have the kinetic device perform a predetermined stroke with a predetermined load, and timing a stroke time period taken by the predetermined stroke;
• and
• C) determining whether the stroke time period is greater than the predetermined time length, and outputting a battery abnormality signal upon determining that the stroke time period is greater than the predetermined time length.