BATTERY MONITORING DEVICE, INTEGRATED CIRCUIT, AND BATTERY MONITORING SYSTEM

This battery monitoring device (100) comprises: a first reference resistor (103) disposed on a path (P2) different from a path (P1) for a current flowing from a battery to a load (102); a transistor (104) for causing the current to flow from the battery to the first reference resistor (103); and an integrated circuit (105). The integrated circuit (105) has: a current measurement unit (112) that measures a first current flowing through the first reference resistor (103); a voltage measurement unit (115) that measures a voltage of a battery (B); and a first calculation unit (118) that calculatesan AC impedance of the battery on the basis of the measured first current and the measured first voltage. 电池监视装置(100)具备在与从电池向负载(102)流动的电流的路径(P1)不同的路径(P2)上配置的第一参照电阻(103)、用于使电流从电池向第一参照电阻(103)流动的晶体管(104)、以及集成电路(105)。集成电路(105)具有计测流过第一参照电阻(103)的第一电流的电流计测部(112)、计测电池(B)的电压的电压计测部(115)、以及根据所计测的第一电流及所计测的第一电压计算电池的交流阻抗的第一计算部(118)。