Energy storage device

The energy storage device according to one embodiment of the present invention comprises: a battery for storing received electric energy in a DC form or outputting the stored electric energy; and a battery manager controlling the battery, the battery manager including: a sensing portion including a plurality of sensors measuring a voltage, a current, and a temperature of the battery; a memory that stores a cycle count that increases as a cycle is executed, and a low-voltage protection level that is a reference value for low-voltage protection that prevents discharge from being equal to or less than a predetermined voltage; and a microcomputer unit that increases the low-voltage protection level when the cycle count reaches a reference number of times. 本发明一实施例的储能装置包括：电池，将接收的电能以直流形式存储，或者输出所存储的电能；以及电池管理器，控制所述电池，所述电池管理器包括：感测部，包括测量所述电池的电压、电流以及温度的复数个传感器；存储器，存储随着执行循环而增加的循环计数、以及作为防止放电为规定电压以下的低电压保护的基准值的低电压保护电平；以及微机单元，若所述循环计数达到基准次数，则使所述低电压保护电平增加。