Integrated dc/dc converter, electrochemical energy storage system, and methods for analyzing electrochemical impedance spectroscopy and working state of electrochemical energy storage apparatus

An electrochemical energy storage system comprising an electrochemical energy storage apparatus, a control system, and an integrated DC/DC converter, the control system is capable of maintaining a stable electric energy output of the electrochemical energy storage apparatus, the integrated DC/DC converter comprising:

• a first DC/DC converter having a first DC/DC converter input end and a first DC/DC converter output end, the first DC/DC converter input end is electrically connected to an electrochemical energy storage apparatus, the first DC/DC converter output end is electrically connected to an electrical load;
• a second DC/DC converter connecting the first DC/DC converter in parallel, the second DC/DC converter having a second DC/DC converter input end and a second DC/DC converter output end;
• a first voltage sensor electrically connected in parallel with the first DC/DC converter input end to detect an electrochemical energy storage apparatus output voltage;
• a second voltage sensor electrically connected in parallel to the first DC/DC converter output end, the second voltage sensor is capable of detecting a first DC/DC converter output voltage;
• a first current sensor connected to the electrochemical energy storage apparatus in series, the first current sensor is capable of detecting an output current of the electrochemical energy storage apparatus;
• a second current sensor connected to the second DC/DC converter input end in series, the second current sensor is capable of detecting a second DC/DC converter input current;
• a third current sensor connected to the first DC/DC converter output end in series, the third current sensor is capable of detecting a first DC/DC converter output current;
• and
• a controller receiving signals from the first voltage sensor, the second voltage sensor, the first current sensor, the second current sensor, and the third current sensor, the controller controlling the first DC/DC converter, the controller is capable of adjusting an output of the electrochemical energy storage apparatus and controlling on and off of the second DC/DC converter, and the controller is also capable of controlling the second DC/DC converter at an on state to adjust an electrochemical energy storage apparatus output current in a current disturbance way to obtain an electrochemical impedance spectroscopy of the electrochemical energy storage apparatus.

A method for analyzing an electrochemical impedance spectroscopy of an electrochemical energy storage apparatus comprising:

• S1, supplying an electric current to a second DC/DC converter to generate a current disturbance signal;
• S2, disturbing an output current of the electrochemical energy storage apparatus by the current disturbance signal;
• S3, detecting a disturbed output current and disturbed output voltage of the electrochemical energy storage apparatus;
• S4, calculating an impedance corresponding to a frequency of the current disturbance signal based on the current disturbance signal, the disturbed output current, and the disturbed output voltage;
• and
• S5, varying the frequency of the current disturbance signal and disturbing again the output current of the electrochemical energy storage apparatus.