Patent ID: 11892514
Assignee: DENSO CORPORATION
Field: Measurement (Instruments)
Classification: CPC G  Y | IPC G

Claim 0:
1. A battery monitoring system for monitoring a state of a battery having battery cells, the system comprising:
a reference signal generator that generates two alternating current (AC) orthogonal reference signals which are sine waves and cosine waves having the same frequency;
an excitation signal generator that generates an excitation signal by processing an in-phase signal which is one of the orthogonal referenced signals;
a current generator that
is composed of a series circuit of a resister element, a driving element, and a resister element,
generates an excitation current by driving the driving element based on the excitation signal and energizes the battery cells, and
outputs two terminal voltage signals from both ends of the resister element;

a current measurer that measures the excitation current generated by the current generator;
a voltage measurer that measures a voltage of a selected battery cell;
a multiplexer that switches connection between the battery cells and the voltage measurer;
an impedance measurer that measures an AC impedance of the selected battery cell based on the excitation current measured by the current measurer and the voltage measured by the voltage measurer; and
a controller that controls measurement of the AC impedance wherein:
the controller selects the selected battery cell by the multiplexer, and causes the impedance measurer to measure the AC impedance,
the current measurer includes a first orthogonal demodulator that is composed of two first multipliers,
the current measurer
inputs the two terminal voltage signals from the current generator,
inputs the two reference signals from the reference signal generator, and
measures the excitation current by performing orthogonal demodulation by causing the two first multipliers to multiply the two terminal voltage signals from the current generator by the two reference signals, respectively,

the voltage measurer includes a second orthogonal demodulator that is composed of two second multipliers, and
the voltage measurer
inputs two terminal voltages of the selected battery cell via the multiplexer,
inputs the two reference signals from the reference signal generator, and
measures a voltage of the selected battery cell by performing orthogonal demodulation by causing the two second multipliers to multiply the two terminal voltages of the selected battery cell by the two reference signals, respectively.