ELECTROCHEMICAL IMPEDANCE SPECTROSCOPY DC-LINK PRE-CHARGE CIRCUIT ON ELECTRIC VEHICLES ONBOARD CHARGER
Systems, apparatuses, and methods for electrochemical impedance spectroscopy (EIS) for use with batteries are provided, including for a pre-charge circuit on electric vehicles that may be used to generate a stimulus signal for EIS analysis of one or more batteries. An exemplary system may comprise a battery, a pre-charge circuitry, and EIS circuitry. The pre-charge circuitry comprising an inverse buck circuitry with a first capacitor and configured to limit an inrush current during loads connection, which includes charging the first capacitor with a periodic waveform. The EIS circuitry receives the periodic waveform and transmits it as a stimulus signal to the battery. The EIS circuitry receives a response signal from the battery in response to the stimulus signal and generates an impedance of the battery based on the response signal.
1 . A system comprising:
at least one battery;
a pre-charge circuitry electrically coupled to a load, wherein the pre-charge circuitry comprises an inverse buck circuitry, wherein the inverse buck circuitry comprises a first capacitor electrically coupled to the load, and wherein the pre-charge circuitry is configured to limit an inrush current during charging of the first capacitor, including charging the first capacitor with a periodic waveform;
an EIS circuitry electrically connected to the pre-charge circuitry to receive the periodic waveform and to transmit the periodic waveform as a stimulus signal to the at least one battery;
wherein the EIS circuitry is further configured to receive a response signal from the at least one battery in response to the stimulus signal; and
wherein the EIS circuitry is further configured to measure an impedance of the battery based on the response signal.
2 . The system of claim 1 , wherein the stimulus signal is comprised of one or more triangular waveforms.
3 . The system of claim 1 , wherein the stimulus signal is comprised of at least three phases, including a beginning phase, a central phase, and a final phase, wherein the periodic waveform is different in of the at least three phases.
4 . The system of claim 1 , wherein the EIS circuitry is configured to receive the periodic waveform during battery charging and battery discharging.
5 . The system of claim 1 further comprising a battery management system, wherein the battery management system is configured to generate a state of health of the at least one battery based on the impedance.
6 . The system of claim 1 , wherein the EIS circuitry is further configured to generate at least one additional signal to superimpose on the periodic waveform of the stimulus signal.
7 . The system of claim 6 , wherein the at least one additional signal comprises a first frequency that is different from the frequency of the periodic waveform.
8 . The system of claim 1 , wherein the pre-charge circuitry is located in a traction inverter, an on-board charge, or an auxiliary DC/DC.
9 . The system of claim 1 , wherein the EIS circuitry is included in an integrated circuit.
10 . The system of claim 1 , wherein the system is a vehicle.
11 . A method comprising:
generate, with a pre-charge circuitry comprising an inverse buck circuitry, a periodic waveform to charge a first capacitor, wherein the pre-charge circuitry is electrically coupled to a load, wherein the inverse buck circuitry comprises the first capacitor electrically coupled to the load, and wherein the pre-charge circuitry is configured to limit an inrush current during charging of the first capacitor;
receiving the periodic waveform at an EIS circuitry;
transmitting, by the EIS circuitry to the at least one battery, the periodic waveform as a stimulus signal;
receiving, at the EIS circuitry from the at least one battery, a response signal based on the stimulus signal; and
measuring an impedance of the at least one battery based on the response signal.
12 . The method of claim 11 , wherein the stimulus signal is comprised of one or more triangular waveforms.
13 . The method of claim 11 , wherein the stimulus signal is comprised of at least three phases, including a beginning phase, a central phase, and a final phase, wherein the periodic waveform is different in of the at least three phases.
14 . The method of claim 11 , wherein receiving the periodic waveform at an EIS circuitry is during battery charging and battery discharging.
15 . The method of claim 11 further comprising:
generating, by a battery management system, a state of health of the at least one battery based on the impedance.
16 . The method of claim 11 further comprising:
generating, by the EIS circuitry, at least one additional signal to superimpose on the periodic waveform of the stimulus signal.
17 . The method of claim 16 , wherein the at least one additional signal comprises a first frequency that is different from the frequency of the periodic waveform.
18 . The method of claim 11 , wherein the pre-charge circuitry is located in a traction inverter, an on-board charge, or an auxiliary DC/DC.
19 . The method of claim 11 , wherein the EIS circuitry is included in an integrated circuit.
20 . The method of claim 11 , wherein the pre-charge circuitry, the EIS circuitry, and the at least one battery are in a vehicle.