Electrochemical impedance spectroscopy data calibration circuit and method for lithium-ion batteries

Abstract

The application provides an electrochemical impedance spectrum data calibration circuit and method for a lithium ion battery, the calibration circuit comprising: an energy storage unit, a battery equivalent unit, a power supply control unit and a standard equivalent circuit unit, the energy storage unit is charged to a preset voltage threshold value through the power supply control unit, then the energy storage unit is in a discharging state through the power supply control unit, the known parameters in the discharging state are obtained, the parasitic inductance value of the lithium ion battery is calculated according to the preset voltage threshold value and the known parameters, and the electrochemical impedance spectrum data is calibrated based on the parasitic inductance value. Under the excitation of medium and high frequency signals, the parasitic inductance effect generated by a large-capacity lithium ion battery can be quickly and accurately calculated, the electrochemical impedance spectrum data is calibrated, and the reliability of the electrochemical impedance spectrum data is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of lithium ion battery detection, and in particular to an electrochemical impedance spectrum data calibration circuit and method for lithium ion batteries. BACKGROUND

[0002] With the rapid development of new energy, lithium ion batteries are increasingly widely used. Currently, the internal core chemical state of lithium ion batteries is mainly fed back by monitoring the electrochemical impedance spectrum data of lithium ion batteries. The monitoring of the electrochemical impedance spectrum data of lithium ion batteries is performed by applying a small-amplitude alternating current signal with a variable frequency to the lithium ion battery, determining the composition of the equivalent circuit inside the lithium ion battery and the size of each element, and then quantitatively analyzing the structure of the electrochemical system and the properties of the electrode process. For measuring large-capacity lithium ion batteries, since the metal current collector is relatively long, a winding process is usually used to make it, which causes the lithium ion battery to generate a parasitic inductance effect under the excitation of a medium-high frequency signal. This parasitic inductance effect causes the measured electrochemical impedance spectrum data to deviate from the actual electrochemical impedance spectrum data of the lithium ion battery, reducing the reliability of the electrochemical impedance spectrum data of the large-capacity lithium ion battery.

[0003] As can be seen from the above, for large-capacity lithium ion batteries, how to obtain an accurate parasitic inductance value and calibrate the electrochemical impedance spectrum data under the excitation of a medium-high frequency signal is a technical problem that needs to be solved at present. SUMMARY

[0004] In view of the above-mentioned shortcomings of the prior art, the present application provides a technical solution for calibrating the electrochemical impedance spectrum data of a lithium ion battery. The charging and discharging state of an energy storage unit is switched and controlled by a power supply control unit. The energy storage unit is first charged to a preset voltage threshold, and then the energy storage unit is in a discharging state. The known parameters in the discharging state are obtained. The parasitic inductance value of the lithium ion battery is calculated based on the preset voltage threshold and the known parameters. The electrochemical impedance spectrum data under the response of a medium-high frequency is calibrated based on the parasitic inductance value. The problem of deviation of the electrochemical impedance spectrum data from the actual value when a large-capacity battery is excited by a medium-high frequency signal is solved. The obtained electrochemical impedance spectrum data is more accurate in precision.

[0005] To achieve the above object and other related objects, the technical solution provided by the present application is as follows.

[0006] An electrochemical impedance spectrum data calibration circuit for a lithium ion battery, comprising:

[0007] The energy storage unit is used to store and release electric quantity; the battery equivalent unit is used to equivalent the internal circuit of the lithium ion battery; the power supply control unit is used to switch control the charging and discharging state of the energy storage unit; the standard equivalent circuit unit provides reference data for the calibration circuit; the energy storage unit is in the charging state through the power supply control unit, so that the energy storage unit reaches the preset voltage threshold, and then the energy storage unit is in the discharging state through the power supply control unit, the known parameters in the discharging state are obtained, the parasitic inductance value of the lithium ion battery is calculated according to the preset voltage threshold and the known parameters, and the electrochemical impedance spectrum data is calibrated based on the parasitic inductance value.

[0008] Optionally, the power supply control unit comprises a direct current constant voltage source, a first PMOS tube and a second PMOS tube, the positive electrode of the direct current constant voltage source is connected to the drain of the first PMOS tube, the gate of the first PMOS tube is connected to a charging signal, the source of the first PMOS tube is connected to the drain of the second PMOS tube, and the source of the first PMOS tube is also connected to one end of the parasitic inductance, the gate of the second PMOS tube is connected to a discharging signal, the source of the second PMOS tube is connected to the negative electrode of the direct current constant voltage source, and the source of the second PMOS tube is also connected to one end of the first inductance.

[0009] Optionally, the battery equivalent unit comprises a first capacitor, a second capacitor, a first resistor, a second resistor, an equivalent constant voltage source and the parasitic inductance, one end of the parasitic inductance is connected to the source of the first PMOS tube, one end of the parasitic inductance is also connected to the drain of the second PMOS tube, the other end of the parasitic inductance is connected to one end of the first capacitor, one end of the first capacitor is also connected to one end of the first resistor, the other end of the first capacitor is connected to the other end of the first resistor, the other end of the first capacitor is also connected to one end of the second capacitor, one end of the second capacitor is also connected to one end of the second resistor, the other end of the second capacitor is connected to the other end of the second resistor, the other end of the second capacitor is also connected to the negative electrode of the equivalent constant voltage source, and the positive electrode of the equivalent constant voltage source is connected to one end of the third capacitor.

[0010] Optionally, the standard equivalent circuit unit comprises the first inductance and a third resistor, one end of the first inductance is connected to the source of the second PMOS tube, one end of the first inductance is also connected to the negative electrode of the direct current constant voltage source, the other end of the first inductance is connected to one end of the third resistor, and the other end of the third resistor is connected to the other end of the third capacitor.

[0011] Optionally, the energy storage unit comprises the third capacitor, one end of the third capacitor is connected to the positive electrode of the equivalent constant voltage source, and the other end of the third capacitor is connected to the other end of the third resistor.

[0012] Optionally, the calibration circuit further comprises a first voltmeter, a negative pole of the first voltmeter being connected to the common terminal of the power supply control unit and the battery equivalent unit, and a positive pole of the first voltmeter being connected to the common terminal of the energy storage unit and the standard equivalent circuit unit.

[0013] Optionally, the calibration circuit further comprises a second voltmeter, a negative pole of the second voltmeter being connected to the common terminal of the power supply control unit and the standard equivalent circuit unit, and a positive pole of the second voltmeter being connected to the common terminal of the energy storage unit and the standard equivalent circuit unit.

[0014] A method for calibrating electrochemical impedance spectrum data of a lithium ion battery, comprising:

[0015] charging the energy storage unit so that the energy storage unit reaches the preset voltage threshold, and then discharging the energy storage unit to obtain a known parameter in a discharging state;

[0016] calculating a parasitic inductance value based on the preset voltage threshold and the known parameter, and calibrating the electrochemical impedance spectrum data based on the parasitic inductance value.

[0017] Optionally, the charging and discharging control of the energy storage unit comprises: when the charging signal is at a low level and the discharging signal is at a high level, the first PMOS transistor is turned on and the second PMOS transistor is turned off, and the energy storage unit is charged by the direct current constant voltage source; when the charging signal is at a high level and the discharging signal is at a low level, the first PMOS transistor is turned off and the second PMOS transistor is turned on, and the discharging string loop is discharged by the energy storage unit.

[0018] Optionally, the step of calculating the parasitic inductance value based on the preset voltage threshold and the known parameter comprises: after the energy storage unit voltage reaches the preset voltage threshold, the energy storage unit is discharged to obtain the known parameter in the discharging state, the known parameter comprising a first inductance value, an equivalent constant voltage source voltage value, a first voltmeter value, and a second voltmeter value; and based on the string loop current equality characteristic, the parasitic inductance value is calculated based on the preset voltage threshold and the known parameter.

[0019] The present application provides a technical solution for calibrating electrochemical impedance spectrum data of a lithium ion battery. The solution charges the energy storage unit through the power control unit, so that the voltage of the energy storage unit reaches a preset voltage threshold. Then the energy storage unit is discharged by the power control unit, and the known parameters in the discharging state are obtained. The parasitic inductance value of the lithium ion battery is calculated according to the preset voltage threshold and the known parameters, and the electrochemical impedance spectrum data is calibrated based on the parasitic inductance value. When a medium-high frequency signal is excited, the present application controls the charging and discharging state of the energy storage unit, obtains the preset voltage threshold in the charging state and the known parameters in the discharging state, calculates the parasitic inductance value of the large-capacity lithium ion battery, calibrates the electrochemical impedance spectrum data of the large-capacity lithium ion battery, removes the interference factors of the electrochemical impedance spectrum data of the large-capacity battery, and improves the precision of the electrochemical impedance spectrum data. BRIEF DESCRIPTION OF DRAWINGS

[0020] Figure 1 is a block diagram of the electrochemical impedance spectrum data calibration circuit of the lithium ion battery in the embodiment of the present application;

[0021] Figure 2 is an internal equivalent circuit diagram of the lithium ion battery when measuring the electrochemical impedance spectrum data in the embodiment of the present application;

[0022] Figure 3 is a circuit diagram for calibrating the electrochemical impedance spectrum data of the lithium ion battery in the embodiment of the present application;

[0023] Figure 4 is a correction contrast curve of the electrochemical impedance spectrum data in the embodiment of the present application.

[0024] BRIEF DESCRIPTION OF DRAWINGS

[0025] ①-parasitic inductance; ②-lithium ion battery equivalent circuit; ③-power control unit; ④-battery equivalent unit; ⑤-energy storage unit; ⑥-standard equivalent circuit unit. DETAILED DESCRIPTION

[0026] The embodiments of the present application are described below through specific and concrete examples. Those skilled in the art can easily understand other advantages and effects of the present application from the disclosure of the present specification. The present application can also be implemented or applied through other different specific embodiments, and various modifications or changes can be made to the details in the specification based on different views and applications without departing from the spirit of the present application. It should be noted that the following embodiments and features in the embodiments can be combined with each other without conflict.

[0027] The inventor has found that in the prior art, the internal reaction state of a lithium ion battery is mainly monitored through electrochemical impedance spectrum data, but some large-capacity lithium ion batteries, such as 18650 lithium ion battery packs and soft-pack lithium ion batteries, have a long metal current collector with large capacity, which is generally made by winding process. When a large-capacity battery is excited by a medium-high frequency signal, a parasitic inductance effect is generated, so that the measured electrochemical impedance spectrum data deviates from the actual electrochemical impedance spectrum data generated by the lithium ion battery, and the reliability of the electrochemical impedance spectrum data is reduced.

[0028] Based on the above shortcomings of the prior art, the present application provides a technical solution for calibrating the electrochemical impedance spectrum data of a lithium ion battery. The energy storage unit is in a charging state by the power control unit, so that the energy storage unit is charged to a preset voltage threshold. Then the energy storage unit is in a discharging state by the power control unit, and the known parameters in the discharging state are obtained. The parasitic inductance value of the lithium ion battery is calculated according to the preset voltage threshold and the known parameters, and the electrochemical impedance spectrum data is calibrated. The interference information of the electrochemical impedance spectrum data is removed by the parasitic inductance value, and the accuracy of the electrochemical impedance spectrum data under a medium-high frequency signal is improved.

[0029] As shown in Figure 1 , the present application provides an electrochemical impedance spectrum data calibration circuit for a lithium ion battery, which comprises:

[0030] an energy storage unit for storing and releasing electric quantity; a battery equivalent unit for equivalent to the internal circuit of the lithium ion battery; a power control unit for switching control of the charging and discharging state of the energy storage unit; a standard equivalent circuit unit for providing reference data for the calibration circuit; the energy storage unit is in a charging state by the power control unit, so that the energy storage unit reaches a preset voltage threshold. Then the energy storage unit is in a discharging state by the power control unit, and the known parameters in the discharging state are obtained. The parasitic inductance value of the lithium ion battery is calculated according to the preset voltage threshold and the known parameters, and the electrochemical impedance spectrum data is calibrated based on the parasitic inductance value.

[0031] In detail, the equivalent circuit model of the lithium ion battery when measuring the electrochemical impedance spectrum data is as shown in Figure 2 , wherein the circuit in the dashed box ① is the parasitic inductance exhibited by the lithium ion battery when measuring the electrochemical impedance spectrum, and the circuit in the dashed box ② is the equivalent circuit of the internal electrochemical process of the lithium ion battery. Since the total current flowing through the battery is equal to the current flowing through the inductance, Lx and the capacitive circuit are in series in the equivalent circuit.

[0032] Let the impedance in the dashed box ② be the effective impedance, and let it be Z(ω):

[0033] Z(ω)=A(ω)+jB(ω) (1)

[0034] Due to the parasitic inductance effect, the actually measured impedance Z'(ω) is:

[0035] Z'(ω) = A'(ω) + jB'(ω) = jωL x + A(ω) + jB(ω) = A(ω) + j[ωL x + B(ω)] (2)

[0036] Therefore, in order to obtain the effective impedance Z(ω), it is necessary to correct according to formula (3-4):

[0037] A(ω) = A'(ω) (3)

[0038] B(ω) = B'(ω) - ω·L x (4)

[0039] It can be seen from formula (4) that the key to correcting the measured value is to obtain the accurate value of the parasitic inductance L x .

[0040] In detail, as shown in Figure 3 , the power supply control unit includes a direct current constant voltage source DC, a first PMOS tube Q1 and a second PMOS tube Q2, the positive electrode of the direct current constant voltage source DC is connected to the drain electrode of the first PMOS tube Q1, the gate electrode of the first PMOS tube Q1 is connected to a charging signal, the source electrode of the first PMOS tube Q1 is connected to the drain electrode of the second PMOS tube Q2, and the source electrode of the first PMOS tube Q1 is also connected to one end of the parasitic inductance L x , the gate electrode of the second PMOS tube Q2 is connected to a discharging signal, the source electrode of the second PMOS tube Q2 is connected to the negative electrode of the direct current constant voltage source DC, and the source electrode of the second PMOS tube Q2 is also connected to one end of the first inductance L1.

[0041] In detail, as shown in Figure 3 , the battery equivalent unit includes a first capacitor C1, a second capacitor C2, a first resistor R1, a second resistor R2, an equivalent constant voltage source VS and a parasitic inductance L x , one end of the parasitic inductance L x is connected to the source electrode of the first PMOS tube Q1, one end of the parasitic inductance L x is also connected to the drain electrode of the second PMOS tube Q2, the other end of the parasitic inductance L x is connected to one end of the first capacitor C1, one end of the first capacitor C1 is also connected to one end of the first resistor R1, the other end of the first capacitor C1 is connected to the other end of the first resistor R1, the other end of the first capacitor C1 is also connected to one end of the second capacitor C2, one end of the second capacitor C2 is also connected to one end of the second resistor R2, the other end of the second capacitor C2 is connected to the other end of the second resistor R2, the other end of the second capacitor C2 is also connected to the negative electrode of the equivalent constant voltage source VS, and the positive electrode of the equivalent constant voltage source VS is connected to one end of the third capacitor C3.

[0042] In detail, as shown in Figure 3 The standard equivalent circuit unit includes a first inductor L1 and a third resistor R3, one end of the first inductor L1 is connected to the source of the second PMOS Q2, the other end of the first inductor L1 is connected to the negative pole of the DC constant voltage source, the other end of the first inductor L1 is connected to one end of the third resistor R3, the other end of the third resistor R3 is connected to the other end of the third capacitor C3.

[0043] In detail, as shown in Figure 3 The energy storage unit includes a third capacitor C3, one end of the third capacitor C3 is connected to the positive pole of the equivalent constant voltage source VS, the other end of the third capacitor C3 is connected to the other end of the third resistor R3.

[0044] In detail, as shown in Figure 3 The calibration circuit further includes a first voltmeter U1, the negative pole of the first voltmeter U1 is connected to the common terminal of the power supply control unit and the battery equivalent unit, and the positive pole of the first voltmeter U1 is connected to the common terminal of the energy storage unit and the standard equivalent circuit unit.

[0045] In detail, as shown in Figure 3 The calibration circuit further includes a second voltmeter U2, the negative pole of the second voltmeter U2 is connected to the common terminal of the power supply control unit and the standard equivalent circuit unit, and the positive pole of the second voltmeter U2 is connected to the common terminal of the energy storage unit and the standard equivalent circuit unit.

[0046] In detail, as shown in Figure 1 Figure 3 The specific working principle of the electrochemical impedance spectrum data calibration circuit of the lithium ion battery is as follows:

[0047] 1) In the first stage, the first PMOS Q1 in the power supply control unit inputs a charging signal as low level and the second PMOS Q2 inputs a discharging signal as high level, the first PMOS Q1 is turned on, the second PMOS Q2 is cut off, the power supply control unit charges the energy storage unit, and the voltage across the energy storage unit reaches a preset voltage threshold U3;

[0048] 2) In the second stage, the first PMOS Q1 in the power supply control unit inputs a charging signal as high level and the second PMOS Q2 inputs a discharging signal as low level, the first PMOS Q1 is cut off, the second PMOS Q2 is turned on, the energy storage unit C3, the battery equivalent unit, the second PMOS Q2 and the standard equivalent circuit unit form a closed loop, and the energy storage unit C3 is in a discharging state.

[0049] Let the current in the closed loop be i, then the voltage reading at U1 is:

[0050]

[0051] ​The voltage reading at U2 is:

[0052]

[0053] Due to the inductance L x With the influence of L1, at the moment of discharging capacitor C3, the current i in the loop is 0, so at t=0, formula (5-6) can be simplified as

[0054]

[0055]

[0056] From formula (7-8), it can be obtained that

[0057]

[0058] That is

[0059]

[0060] By simultaneously solving equations (3, 4, 10), the final correction method of impedance can be obtained as:

[0061] A(ω)=A'(ω) (11)

[0062]

[0063] After calculating the parasitic inductance value of the lithium ion battery by the calibration circuit of the present application, the formula (12) of the corrected impedance is obtained, Figure 4 The comparison curve is corrected by the calibration circuit of the present application on the electrochemical impedance spectrum data of the lithium ion battery. Through the correction of the data, the parasitic inductance effect is effectively eliminated.

[0064] The present application also provides a method for calibrating the electrochemical impedance spectrum data of a lithium ion battery, which comprises:

[0065] S1, providing the electrochemical impedance spectrum data calibration circuit of the lithium ion battery as described above;

[0066] S2, charging the energy storage unit so that the energy storage unit reaches a preset voltage threshold, and then discharging the energy storage unit to obtain the known parameters in the discharged state;

[0067] In detail, the charging and discharging control of the energy storage unit C3 comprises: when the charging signal is low and the discharging signal is high, the first PMOS tube Q1 is turned on and the second PMOS tube Q2 is turned off, and the energy storage unit C3 is charged by a direct current constant voltage source; when the charging signal is high and the discharging signal is low, the first PMOS tube Q1 is turned off and the second PMOS tube Q2 is turned on, and the discharge string loop is discharged by the energy storage unit C3.

[0068] S3, calculating the parasitic inductance value by the preset voltage threshold U3 and the known parameters, and calculating the parasitic inductance value L X The electrochemical impedance spectrum data is corrected.

[0069] In detail, the parasitic inductance value L X is calculated by the preset voltage threshold U3 and the known parameters. VS The step includes: charging the energy storage unit C3 so that the voltage of the energy storage unit C3 reaches the preset voltage threshold U3, then discharging the energy storage unit C3 to obtain the known parameters in the discharging state, the known parameters including a first inductance value L1, an equivalent constant voltage source voltage value U X , a first voltmeter value U1 and a second voltmeter value U2.

[0070] The embodiments of the present application clearly describe that the energy storage unit is in the charging state by the power supply control unit, and the energy storage unit is charged to the preset voltage threshold, then the energy storage unit is discharged by the power supply control unit to obtain the known parameters of the discharging circuit, the parasitic inductance value is calculated according to the preset voltage threshold and the known parameters, and the electrochemical impedance data of the lithium ion battery is calibrated based on the parasitic inductance value. The present application can calculate the accurate parasitic inductance value, the parasitic inductance effect generated when the medium-high frequency signal is excited can be eliminated by the parasitic inductance value, the electrochemical impedance spectrum data of the large-capacity battery when responding to the medium-high frequency is calibrated, and reliable electrochemical impedance spectrum data for studying the internal chemical reaction of the lithium ion battery is provided.

[0071] The above embodiments only exemplarily illustrate the principles and effects of the present application, and are not used to limit the present application. Any person skilled in the art can modify or change the above embodiments without departing from the spirit and scope of the present application. Therefore, all equivalent modifications or changes completed by those skilled in the art without departing from the spirit and technical thought of the present application should be covered by the claims of the present application.

Claims

1. A lithium-ion battery electrochemical impedance spectroscopy data calibration circuit, characterized in that: include: Energy storage unit, used to store and release electricity; A battery equivalent unit, used to be equivalent to the internal circuit of the lithium-ion battery; A power control unit, configured to control the switching of the charge and discharge states of the energy storage unit; A standard equivalent circuit unit, providing reference data for the calibration circuit; placing the energy storage unit in a charging state by the power control unit so that the energy storage unit reaches a preset voltage threshold, then placing the energy storage unit in a discharging state by the power control unit, obtaining known parameters in the discharging state, calculating a parasitic inductance value of the lithium-ion battery according to the preset voltage threshold and the known parameters, and calibrating the electrochemical impedance spectroscopy data based on the parasitic inductance value; The power control unit includes a DC constant voltage source, a first PMOS transistor, and a second PMOS transistor. The positive electrode of the DC constant voltage source is connected to the drain of the first PMOS transistor, the gate of the first PMOS transistor is connected to a charging signal, the source of the first PMOS transistor is connected to the drain of the second PMOS transistor, the source of the first PMOS transistor is also connected to one end of a parasitic inductor, the gate of the second PMOS transistor is connected to a discharge signal, the source of the second PMOS transistor is connected to the negative electrode of the DC constant voltage source, and the source of the second PMOS transistor is also connected to one end of the first inductor.

2. The electrochemical impedance spectroscopy data calibration circuit for lithium-ion batteries according to claim 1, wherein: The battery equivalent unit includes a first capacitor, a second capacitor, a first resistor, a second resistor, an equivalent constant voltage source and the parasitic inductor, one end of the parasitic inductor is connected to the source of the first PMOS tube, one end of the parasitic inductor is also connected to the drain of the second PMOS tube, the other end of the parasitic inductor is connected to one end of the first capacitor, one end of the first capacitor is also connected to one end of the first resistor, the other end of the first capacitor is connected to the other end of the first resistor, the other end of the first capacitor is also connected to one end of the second capacitor, one end of the second capacitor is also connected to one end of the second resistor, the other end of the second capacitor is connected to the other end of the second resistor, the other end of the second capacitor is also connected to the negative electrode of the equivalent constant voltage source, and the positive electrode of the equivalent constant voltage source is connected to one end of the third capacitor.

3. The electrochemical impedance spectroscopy data calibration circuit for a lithium-ion battery according to claim 2, wherein: The standard equivalent circuit unit includes the first inductor and the third resistor, one end of the first inductor is connected to the source of the second PMOS transistor, one end of the first inductor is also connected to the negative electrode of the DC constant voltage source, the other end of the first inductor is connected to one end of the third resistor, and the other end of the third resistor is connected to the other end of the third capacitor.

4. The electrochemical impedance spectroscopy data calibration circuit for a lithium-ion battery according to claim 3, wherein: The energy storage unit includes the third capacitor, one end of the third capacitor is connected to the positive electrode of the equivalent constant voltage source, and the other end of the third resistor is connected to the other end of the third resistor.

5. The electrochemical impedance spectroscopy data calibration circuit for a lithium-ion battery according to claim 1, wherein: The calibration circuit also includes a first voltmeter, the negative pole of the first voltmeter is connected to the common end of the power control unit and the battery equivalent unit, and the positive pole of the first voltmeter is connected to the common end of the energy storage unit and the standard equivalent circuit unit.

6. The electrochemical impedance spectroscopy data calibration circuit for a lithium-ion battery according to claim 1, wherein: The calibration circuit also includes a second voltmeter, the negative pole of the second voltmeter is connected to the common end of the power control unit and the standard equivalent circuit unit, and the positive pole of the second voltmeter is connected to the common end of the energy storage unit and the standard equivalent circuit unit.

7. A method for calibrating electrochemical impedance spectroscopy data of a lithium-ion battery, characterized in that: include: Providing an electrochemical impedance spectroscopy data calibration circuit for a lithium-ion battery according to any one of claims 2 to 6; charging the energy storage unit until the energy storage unit reaches the preset voltage threshold, and then discharging the energy storage unit to obtain the known parameters in the discharged state; The parasitic inductance value is calculated using the preset voltage threshold and the known parameters, and the electrochemical impedance spectroscopy data is corrected according to the parasitic inductance value.

8. The method for calibrating electrochemical impedance spectroscopy data of a lithium-ion battery according to claim 7, wherein: Controlling the charging and discharging of the energy storage unit includes: When the charging signal is at a low level and the discharging signal is at a high level, the first PMOS transistor is turned on and the second PMOS transistor is turned off, and the energy storage unit is charged by the DC constant voltage source; When the charging signal is at a high level and the discharging signal is at a low level, the first PMOS transistor is turned off and the second PMOS transistor is turned on, and the discharging series loop is discharged through the energy storage unit.

9. The method for calibrating electrochemical impedance spectroscopy data of a lithium-ion battery according to claim 8, wherein: The step of calculating the parasitic inductance value by using the preset voltage threshold and the known parameters includes: charging the energy storage unit so that the voltage of the energy storage unit reaches the preset voltage threshold, controlling the energy storage unit to discharge, and obtaining the known parameters in the discharge state, wherein the known parameters include a first inductance value, an equivalent constant voltage source voltage value, a first voltmeter value, and a second voltmeter value; Based on the current equality characteristic of the discharge series circuit, the parasitic inductance value is calculated according to the preset voltage threshold and the known parameters.

Images