Patent ID: 9225181
Filing Date: 2015-12-29
Classification: H02J

Abstract:
1. A power storage system comprising: battery charger which charges a battery pack having a battery and a battery voltage detection circuit detecting a terminal voltage of the battery, wherein said battery charger is structured such as to acquire terminal voltage information of the battery from the battery voltage detection circuit of the battery pack in a charging process, carry out a constant current charge control in a state in which the terminal voltage of the battery is equal to or lower than a previously determined reference voltage value of said battery and switch to a constant voltage charge control maintaining the output voltage of the battery charger in the case that the terminal voltage of the battery goes beyond said reference voltage value, thereby carrying on the charge until the battery is fully charged, wherein said battery charger comprises: at least one main circuit which supplies electric power to the battery pack; at least one main control circuit which controls an output current and an output voltage of said at least one main circuit; at least one output current detection circuit which detects a magnitude of the output current of said at least one main circuit so as to input to said at least one main control circuit; at least one output voltage detection circuit which detects a magnitude of the output voltage of said at least one main circuit so as to input to said at least one main control circuit; and an auxiliary control circuit which acquires a terminal voltage of the batter in said batter pack, compares the acquired terminal voltage with the previously determined reference voltage value, and informs said at least one main control circuit of the fact that the terminal voltage goes beyond the reference voltage value, and wherein said at least one main control circuit refers to an output current value which is input from said at least one output current detection circuit, an output voltage value which is input from said at least one output voltage detection circuit, and an information signal which is input from the auxiliary control circuit, controls said at least one main circuit so that said at least one main circuit sets a rated charge current value of the battery pack as a charge current control target value so as to carry out a constant current charge in a state in which the information signal is not input, and controls said at least one main circuit so that said at least one main circuit sets an output voltage value of said at least one main circuit when the terminal voltage of the battery goes beyond the reference voltage value as a charge voltage control target value so as to carry out a constant voltage charge in a state in which the information signal is input.