On-line electrochemical impedance spectroscopy detection system for power battery

Abstract

The utility model provides an on-line electrochemical impedance spectroscopy detection system for a power battery, which comprises a battery pack, a BMS (Battery Management System), an excitation switch and an excitation resistor which are arranged on a vehicle, and the battery pack is connected in series with the excitation switch and the excitation resistor; the BMS is connected with the battery pack; the BMS is configured to control the on-off of the excitation switch according to a certain frequency, receive a response signal of the battery pack, and obtain an impedance spectrum according to the response signal. According to the utility model, the existing BMS and the whole vehicle electrical system on the electric vehicle are utilized, the BMS controls the on-off of the excitation switch according to a certain frequency, the pulse disturbance is performed on the battery pack, the battery pack can generate response, the response signal is acquired through the BMS, the response signal is processed to obtain the impedance spectrum, and the vehicle battery impedance spectrum detection is completed. The electrochemical impedance spectroscopy detection is integrated to the vehicle, the existing electric vehicle does not need to be greatly modified, the cost is low, and the electrochemical impedance spectroscopy detection device has extremely high market application prospects and popularization prospects.

Description

Technical Field

[0001] The utility model relates to the technical field of secondary batteries, in particular to an online electrochemical impedance spectroscopy detection system for power batteries. Background Art

[0002] With the increasing popularity of electric vehicles, the market's performance requirements for electric vehicles are increasing day by day; and the performance of electric vehicle batteries is directly related to key indicators such as the electric vehicle's range, service life, and safety, and is highly valued by vehicle manufacturers.

[0003] The Battery Management System (BMS) is an important component of power batteries. One of its main functions is state estimation, which means obtaining information by sampling the battery pack and estimating key operating indicators that cannot be directly measured, such as state of charge, state of health, and internal temperature.

[0004] However, current electric vehicle battery management systems primarily collect battery signals such as voltage, temperature, and current. These parameters cannot directly reflect the electrochemical reaction activity within the battery. Battery management systems are often unable to predict or provide early warning of battery life degradation, aging, or thermal runaway. In the field of electrochemistry, electrochemical workstations are often used to obtain battery impedance spectra to better assess battery status. However, electrochemical workstations are bulky and cannot be directly integrated into the battery management system of an actual vehicle.

[0005] To this end, this patent proposes a solution that can perform online electrochemical impedance spectroscopy measurements. Utility Model Content

[0006] In order to solve the above technical problems, the present invention discloses an online electrochemical impedance spectroscopy detection system for power batteries. The technical solution of the present invention is implemented as follows:

[0007] An online electrochemical impedance spectroscopy testing system for a power battery includes a battery pack and a BMS mounted on a vehicle, as well as an excitation switch and an excitation resistor for the entire vehicle electrical system;

[0008] The first end of the excitation switch is communicatively connected to the BMS, one of the second and third ends of the excitation switch is connected to the first end of the excitation resistor, the other of the second and third ends of the excitation switch is connected to the first end of the battery pack, and the excitation resistor is connected to the second end of the battery pack;

[0009] The BMS is connected to the battery pack;

[0010] The BMS is configured to control the excitation switch to be turned on or off according to a preset frequency, obtain a response signal from the battery pack, and obtain an impedance spectrum of the battery pack based on the response signal and the excitation resistor.

[0011] Preferably, the BMS includes a signal generator, a signal collector and a data processor:

[0012] The signal generator is in communication with the excitation switch, the signal collector is in communication with the battery pack, and the data processor is in communication with the signal collector;

[0013] The signal generator is configured to send a control signal to the excitation switch and control the excitation switch to be turned on or off according to a preset frequency;

[0014] The signal collector is configured to acquire a response signal from the battery pack and generate signal data according to the response signal;

[0015] The data processor is configured to acquire and process the signal data to obtain an impedance spectrum.

[0016] Preferably, the excitation resistor is a pre-charge resistor of the vehicle electrical system;

[0017] The vehicle electrical system further includes a pre-charge MOS tube and a relay; a first end of the pre-charge MOS tube is connected to the BMS, a second end of the pre-charge MOS tube is connected to the first end of the battery pack, and a third end of the pre-charge MOS tube is connected to the first end of the excitation resistor; the BMS is configured to control the switch of the pre-charge MOS tube;

[0018] The first end of the relay is connected to the second end of the pre-charge MOS tube, the second end of the relay is connected to the second end of the excitation resistor, the relay is communicatively connected to the BMS, and the BMS is configured to control the switch of the relay;

[0019] The second end of the excitation resistor is connected to the first end of the excitation switch, and the second end of the excitation switch is connected to the second end of the battery pack.

[0020] Preferably, the excitation resistor is a pre-charge resistor in the vehicle electrical system; the excitation switch is an IGBT in the motor control system, and the motor control system is electrically connected between the motor and the battery pack to regulate the rotation of the motor;

[0021] The vehicle electrical system further includes a pre-charge MOS tube and a relay, wherein a first end of the pre-charge MOS tube is connected to the BMS, a second end of the pre-charge MOS tube is connected to a first end of the battery pack, and a third end of the pre-charge MOS tube is connected to a first end of the excitation resistor; the BMS is configured to control the switch of the pre-charge MOS tube;

[0022] The first end of the relay is connected to the first end of the pre-charge MOS tube, the second end of the relay is connected to the second end of the excitation resistor, the relay is communicatively connected to the BMS, and the BMS is configured to control the switch of the relay;

[0023] The second end of the excitation resistor is connected to the first end of the excitation switch, and the second end of the excitation switch is electrically connected to the second end of the battery pack;

[0024] The motor control system is further provided with a communication module, which is communicatively connected with the signal generator and the excitation switch.

[0025] Preferably, the excitation resistor is a PTC heating resistor in the vehicle electrical system; the excitation switch is a PTCMOS tube in the vehicle electrical system;

[0026] The vehicle electrical system also includes a relay and a motor;

[0027] The first end of the relay is connected to the first end of the battery pack, the second end of the relay is connected to the first end of the excitation switch, the second end of the excitation switch is connected to the first end of the excitation resistor, and the second end of the excitation resistor is connected to the second end of the battery pack. The relay is communicatively connected to the BMS, and the BMS is configured to control the switch of the relay;

[0028] One end of the motor is electrically connected to the first end of the battery pack, and the other end of the motor is electrically connected to the second end of the battery pack.

[0029] Preferably, the first end or the second end of the excitation switch is connected to an EIS fuse.

[0030] Preferably, the signal collector includes a voltage acquisition module and a current acquisition module;

[0031] The voltage acquisition module is connected to the battery pack and the data processor, and is configured to acquire a response voltage of the battery pack;

[0032] The current acquisition module is connected to the battery pack and the data processor, and is configured to acquire a response current of the battery pack;

[0033] The data processor is configured to obtain a response voltage and a response current.

[0034] Preferably, the battery pack includes a plurality of battery cells, the voltage acquisition module is connected to each of the battery cells, and the voltage acquisition module is configured to acquire a response voltage of each of the battery cells.

[0035] Preferably, the data processor comprises:

[0036] An impedance spectrum calculation module for calculating the real and imaginary parts of the impedance, wherein the impedance spectrum calculation module is connected to the signal collector;

[0037] a drawing module for receiving the real part and the imaginary part of the impedance and drawing a Nyquist curve, wherein the drawing module is connected to the impedance spectrum calculation module;

[0038] A storage module for storing the impedance and the corresponding Nyquist curve, wherein the storage module is connected to the impedance spectrum calculation module and the drawing module.

[0039] Preferably, the excitation switch is an NMOS transistor or a PMOS transistor.

[0040] This utility model utilizes the existing BMS and the vehicle's electrical system. The BMS controls the excitation switch at a certain frequency, causing the battery pack to respond to pulse disturbances. The BMS then acquires the response signal and processes it to generate an impedance spectrum, completing the vehicle's battery impedance spectrum testing. This integration of electrochemical impedance spectroscopy testing into the vehicle eliminates the need for significant modifications to existing electric vehicles, resulting in low costs and promising market applications and widespread adoption. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only one embodiment of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0042] Identical components are denoted by the same reference numerals. It should be noted that the terms "front," "rear," "left," "right," "upper," and "lower" used in the following description refer to directions in the accompanying drawings, and the terms "bottom," "top," "inner," and "outer" refer to directions toward or away from the geometric center of a particular component, respectively.

[0043] Figure 1 This is a schematic diagram of the overall structure of Example 1;

[0044] Figure 2 This is the architecture diagram of the BMS in Example 1;

[0045] Figure 3 This is a schematic diagram of the overall structure of Example 2;

[0046] Figure 4 This is a schematic diagram of the overall structure of Example 3.

[0047] In the above drawings, the figure numbers represent:

[0048] 1. Excitation switch;

[0049] 2. Excitation resistor;

[0050] 3. Battery pack;

[0051] 4, BMS; 4-1, signal generator; 4-2, signal collector; 4-3, data processor;

[0052] 5. Pre-charge MOS tube;

[0053] 6. Relay;

[0054] 7. EIS fuse;

[0055] 8, motor control system; 8-1, communication module;

[0056] M, motor. DETAILED DESCRIPTION

[0057] The following will be combined with the embodiments of the present invention and the accompanying drawings to clearly and completely describe the technical solutions of the present invention. Obviously, the embodiments described are only some of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0058] Unless otherwise defined, all technical and scientific terms used in the present invention have the same meanings as those commonly understood by technicians in the technical field to which the present invention belongs; the terms used in the specific implementation methods are only for the purpose of describing specific embodiments and are not intended to limit the present invention; the terms "including" and "having" in the description and claims of the present invention and the above-mentioned drawings and any variations thereof are intended to cover non-exclusive inclusions.

[0059] In the description of the specific embodiments of this utility model, the technical terms "first" and "second" are used only to distinguish different objects and should not be understood to indicate or imply relative importance or implicitly indicate the number, specific order, or primary and secondary relationship of the technical features indicated. In the description of the embodiments of this utility model, the meaning of "plurality" is more than two, unless otherwise clearly and specifically limited.

[0060] References to "embodiments" in this disclosure mean that a particular feature, structure, or characteristic described in connection with the embodiment may be included in at least one embodiment of the disclosure. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor does it constitute an independent or alternative embodiment that is mutually exclusive of other embodiments. It is understood, both explicitly and implicitly, by those skilled in the art that the embodiments described in this disclosure may be combined with other embodiments.

[0061] In the description of the embodiments of the present invention, the term "and / or" is merely a description of the association relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent the following three situations: A exists alone, A and B exist simultaneously, and B exists alone. In addition, the character " / " in the present invention generally indicates that the related objects are in an "or" relationship.

[0062] It should be noted that, for the convenience of description, in the following embodiments, all identical technical features are marked with the same symbols.

[0063] The following examples will be used to more specifically describe the embodiments of the present invention. It should be noted that the embodiments of the present invention are not limited to these examples.

[0064] Example 1

[0065] In a specific embodiment 1, Figure 1 As shown, an online electrochemical impedance spectroscopy testing system for a power battery includes an excitation switch 1 and an excitation resistor 2 provided in the vehicle electrical system, as well as a battery pack 3 and a BMS 4 provided on the vehicle. The excitation switch 1 also includes one end electrically connected to one end of the excitation resistor 2, and one end electrically connected to one end of the excitation resistor 2; one of the other ends of the excitation switch 1 and the other end of the excitation resistor 2 is connected to a first end of the battery pack 3, and the other of the other end of the excitation switch 1 and the other end of the excitation resistor 2 is connected to a second end of the battery pack 3.

[0066] BMS4 is connected to the battery pack; BMS4 is configured to control the excitation switch 1 to be turned on or off according to a preset frequency, and obtain a response signal from the battery pack 3, and obtain an impedance spectrum of the battery pack 3 based on the response signal and the excitation resistor 2.

[0067] In this embodiment, BMS4 is an existing BMS system on the vehicle, which implements battery management. The vehicle electrical system is an existing control system on the vehicle, which can implement functions such as vehicle start and stop.

[0068] In this embodiment, the BMS 4 controls the activation switch 1 at a certain frequency. This triggers a pulse disturbance in the battery pack 3, causing the battery pack 3 to respond. The BMS 4 then acquires the response signal and processes it to generate an impedance spectrum, completing the vehicle battery impedance spectrum test. This utility model integrates the online electrochemical impedance spectroscopy (EIS) test function into existing electric vehicles, utilizing only the vehicle's existing system for testing, resulting in a low modification cost.

[0069] In some embodiments, as Figure 2 As shown, the BMS 4 includes a signal generator 4 - 1 , a signal collector 4 - 2 and a data processor 4 - 3 .

[0070] The signal generator 4-1 is connected to the excitation switch 1 and is used to send an on / off signal to the excitation switch 1 at a certain frequency; the signal collector 4-2 is connected to the battery pack 3 and is used to obtain the response signal of the battery pack 3; the data processor 4-3 is connected to the signal collector 4-2 and is used to receive the signal data transmitted by the signal collector 4-2 and obtain the impedance spectrum after processing.

[0071] In this embodiment, the excitation resistor 2 is an existing pre-charging resistor in the vehicle electrical system.

[0072] In this embodiment, the excitation switch 1 is a MOS tube.

[0073] In this embodiment, the vehicle electrical system further includes a pre-charge MOSFET 5 and a relay 6. A first end of the pre-charge MOSFET 5 is connected to the BMS 4, a second end of the pre-charge MOSFET 5 is connected to a first end of the battery pack 3, and a third end of the pre-charge MOSFET 5 is connected to a first end of the excitation resistor 2. The BMS 4 is configured to control the switching of the pre-charge MOSFET 5.

[0074] The first end of the relay 6 is connected to the second end of the pre-charge MOS tube 5, the second end of the relay 6 is connected to the second end of the excitation resistor 2, the relay 6 is communicated with the BMS4, and the BMS4 is configured to control the switch of the relay 6; the second end of the excitation resistor 2 is connected to the first end of the excitation switch 1, and the second end of the excitation switch 1 is connected to the second end of the battery pack 3.

[0075] The vehicle electrical system further includes a motor M, which is electrically connected to a battery pack 3 , and the battery pack 3 is used to provide power to the motor M.

[0076] In this embodiment, the first end of the battery pack 3 is connected to one end of the motor M, and the second end of the battery pack 3 is connected to the second end of the motor M. In this embodiment, before starting the motor M, the relay 6 can be disconnected and the pre-charge MOS transistor 5 can be closed. When the pre-charge voltage reaches the target voltage, the relay 6 can be closed again to protect the main circuit. During testing, the relay 6 is disconnected and the pre-charge MOS transistor 5 is closed. The excitation switch 1 is controlled by the signal generator 4-1 to implement impedance spectrum detection. This does not affect the original electrical architecture. In addition, the excitation switch is a MOS transistor, which is relatively low in cost.

[0077] In some preferred embodiments, an EIS fuse 7 is further provided on the series circuit of the excitation switch 1 and the battery pack 3 .

[0078] By providing an EIS fuse 7 between the excitation switch 1 and the battery pack 3 , the fuse can be disconnected when the current is too large, thereby protecting the circuit.

[0079] In some embodiments, the signal collector 4-2 includes a voltage acquisition module and a current acquisition module. The voltage acquisition module is connected in parallel with the battery pack 3, and is used to measure the response voltage of the battery pack 3 and send the response voltage signal to the data processor; the current acquisition module is connected to the battery pack 3 and the excitation switch 1 circuit, and is used to measure the current of the battery pack 3 and send the current signal to the data processor.

[0080] Through the above arrangement, it is possible to measure the response signal of the battery pack 3 so that the data processor can process the response signal.

[0081] In some preferred embodiments, the battery pack 3 includes a plurality of battery cells connected in series, and the voltage acquisition module includes a plurality of acquisition lines connected to both ends of the battery cells.

[0082] By connecting multiple acquisition lines at both ends of each battery cell, the voltage of each battery cell can be collected; and the currents of the series-connected battery cells are the same, so the response voltage and current of a single battery cell are obtained, which can realize the detection of the impedance spectrum of a single battery cell.

[0083] In some embodiments, the BMS 4 uses a 16-bit AFI chip.

[0084] The 16-bit AFI chip can ensure the measurement accuracy of the response signal.

[0085] In some preferred embodiments, the data processor includes an impedance spectrum calculation module, a plotting module, and a storage module. The impedance spectrum calculation module is connected to the signal collector 4-2 and processes the received acoustic signal using Fourier transform to obtain the amplitude and phase angle of the response current and response voltage, and calculates the real and imaginary parts of the impedance. The plotting module is connected to the impedance spectrum calculation module, receives the real and imaginary parts of the impedance and plots the Nyquist curve. The storage module is connected to the impedance spectrum calculation module and the plotting module and is used to store the impedance and the corresponding Nyquist curve.

[0086] Example 2

[0087] like Figure 3 As shown, this embodiment differs from Embodiment 1 in that the excitation switch 1 in this embodiment is a PTCMOS transistor originally used to control heating in the vehicle electrical system, and the excitation resistor 2 is a PTC heating resistor originally used for heating in the vehicle electrical system. The vehicle electrical system also includes a relay 6 and a motor M.

[0088] Specifically, the first end of relay 6 is connected to the first end of battery pack 3, the second end of relay 6 is connected to the first end of excitation switch 1, the second end of excitation switch 1 is connected to the first end of excitation resistor 2, and the second end of excitation resistor 2 is connected to the second end of battery pack 3. Relay 6 is in communication with BMS 4, which is configured to control the switching of relay 6. The two ends of motor M are respectively connected to the first and second ends of battery pack 3. When the vehicle needs to be heated, excitation switch 1 is closed, and the battery pack 3, excitation switch 1, and excitation resistor 2 form a circuit to achieve heating.

[0089] During impedance spectrum testing, this embodiment uses BMS 4 to control the activation switch 1 at a certain frequency. This triggers a pulse disturbance in the battery pack 3, causing the battery pack 3 to respond. The BMS 4 then acquires the response signal and processes it to generate an impedance spectrum, completing the impedance spectrum test for the vehicle battery. This utility model integrates online electrochemical impedance spectroscopy testing into existing electric vehicles, utilizing only the vehicle's existing system for testing, resulting in lower modification costs.

[0090] This embodiment uses the original PTCMOS tube of the vehicle as the excitation switch 1 to receive the signal of the signal generator 4-1 to implement impedance spectrum detection, which will not affect the original electrical architecture and has a low implementation cost.

[0091] Example 3

[0092] like Figure 4As shown, the difference between this embodiment and embodiment 1 is that the excitation switch 1 in this embodiment is an IGBT in the motor control system 8 in the vehicle electrical system. The motor control system is electrically connected between the motor M and the battery pack 3 and is used to adjust the rotation of the motor M; the motor control system 8 is used to adjust the rotation of the motor.

[0093] The motor control system 8 is equipped with numerous IGBTs. By cooperating with each other and closing the IGBTs in a specific sequence, control and coordination of the motor M can be achieved. In this embodiment, one group of IGBTs is selected as the excitation switch 1. During impedance spectrum testing, by closing one IGBT and switching the other IGBTs at a specific frequency, pulse perturbations of the battery pack 3 can be achieved, thereby enabling electrochemical impedance spectroscopy testing. (Alternatively, when the excitation switch 1 is fully closed, the relay 6 is disconnected, and the MOS transistor 5 is switched on and off at a specific frequency, thereby achieving pulse perturbations of the battery pack 3.)

[0094] Specifically, the vehicle electrical system also includes a pre-charge MOS tube 5 and a relay 6. Figure 4 As shown, the first end of the pre-charge MOS tube 5 is connected to the BMS4, the second end of the pre-charge MOS tube 5 is connected to the first end of the battery pack 3, and the third end of the pre-charge MOS tube 5 is connected to the first end of the excitation resistor 2; the BMS4 is configured to control the switch of the pre-charge MOS tube 5; the first end of the relay 6 is connected to the second end of the pre-charge MOS tube 5, the second end of the relay 6 is connected to the second end of the excitation resistor 2, the relay 6 is communicatively connected to the BMS4, and the BMS4 is configured to control the switch of the relay 6; the second end of the excitation resistor 2 is connected to the first end of the excitation switch 1, and the second end of the excitation switch 1 is electrically connected to the second end of the battery pack 3; a communication module 8-1 is also provided in the motor control system 8, and the communication module 8-1 is communicatively connected to the signal generator 4-1 and the excitation switch 1, and the signal generator 4-1 in the BMS4 realizes the on or off control of the excitation switch 1 through the signal generator 4-1, thereby realizing the detection of the electrochemical impedance spectrum.

[0095] The utility model integrates the function of electrochemical impedance spectroscopy online detection into an existing electric vehicle, and only uses the original system on the vehicle for detection, so the modification cost is low.

[0096] It should be pointed out that the above is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A power battery online electrochemical impedance spectroscopy detection system, comprising a battery pack and a BMS mounted on a vehicle, characterized in that: It also includes the excitation switch and excitation resistor of the vehicle electrical system; The first end of the excitation switch is communicatively connected to the BMS, one of the second and third ends of the excitation switch is connected to the first end of the excitation resistor, the other of the second and third ends of the excitation switch is connected to the first end of the battery pack, and the excitation resistor is connected to the second end of the battery pack; The BMS is connected to the battery pack; The BMS is configured to control the excitation switch to be turned on or off according to a preset frequency, obtain a response signal from the battery pack, and obtain an impedance spectrum of the battery pack based on the response signal and the excitation resistor.

2. The power battery online electrochemical impedance spectroscopy detection system according to claim 1, characterized in that: The BMS includes a signal generator, a signal collector and a data processor: The signal generator is in communication with the excitation switch, the signal collector is in communication with the battery pack, and the data processor is in communication with the signal collector; The signal generator is configured to send a control signal to the excitation switch and control the excitation switch to be turned on or off according to a preset frequency; The signal collector is configured to acquire a response signal from the battery pack and generate signal data according to the response signal; The data processor is configured to acquire and process the signal data to obtain an impedance spectrum.

3. The power battery online electrochemical impedance spectroscopy detection system according to claim 1, characterized in that: The excitation resistor is the pre-charge resistor of the vehicle electrical system; The vehicle electrical system further includes a pre-charge MOS tube and a relay; a first end of the pre-charge MOS tube is connected to the BMS, a second end of the pre-charge MOS tube is connected to the first end of the battery pack, and a third end of the pre-charge MOS tube is connected to the first end of the excitation resistor; the BMS is configured to control the switch of the pre-charge MOS tube; The first end of the relay is connected to the second end of the pre-charge MOS tube, the second end of the relay is connected to the second end of the excitation resistor, the relay is communicatively connected to the BMS, and the BMS is configured to control the switch of the relay; The second end of the excitation resistor is connected to the first end of the excitation switch, and the second end of the excitation switch is connected to the second end of the battery pack.

4. The power battery online electrochemical impedance spectroscopy detection system according to claim 2, characterized in that: The excitation resistor is a pre-charge resistor in the vehicle electrical system; the excitation switch is an IGBT in the motor control system, which is electrically connected between the motor and the battery pack and is used to regulate the rotation of the motor; The vehicle electrical system further includes a pre-charge MOS tube and a relay, wherein a first end of the pre-charge MOS tube is connected to the BMS, a second end of the pre-charge MOS tube is connected to a first end of the battery pack, and a third end of the pre-charge MOS tube is connected to a first end of the excitation resistor; the BMS is configured to control the switch of the pre-charge MOS tube; The first end of the relay is connected to the first end of the pre-charge MOS tube, the second end of the relay is connected to the second end of the excitation resistor, the relay is communicatively connected to the BMS, and the BMS is configured to control the switch of the relay; The second end of the excitation resistor is connected to the first end of the excitation switch, and the second end of the excitation switch is electrically connected to the second end of the battery pack; The motor control system is further provided with a communication module, which is communicatively connected with the signal generator and the excitation switch.

5. The power battery online electrochemical impedance spectroscopy detection system according to claim 1, characterized in that: The excitation resistor is a PTC heating resistor in the vehicle electrical system; the excitation switch is a PTCMOS tube in the vehicle electrical system; The vehicle electrical system also includes a relay and a motor; The first end of the relay is connected to the first end of the battery pack, the second end of the relay is connected to the first end of the excitation switch, the second end of the excitation switch is connected to the first end of the excitation resistor, and the second end of the excitation resistor is connected to the second end of the battery pack. The relay is communicatively connected to the BMS, and the BMS is configured to control the switch of the relay; One end of the motor is electrically connected to the first end of the battery pack, and the other end of the motor is electrically connected to the second end of the battery pack.

6. The power battery online electrochemical impedance spectroscopy detection system according to claim 1, characterized in that: The first end or the second end of the excitation switch is connected to an EIS fuse.

7. The power battery online electrochemical impedance spectroscopy detection system according to claim 2, characterized in that: The signal collector includes a voltage acquisition module and a current acquisition module; The voltage acquisition module is connected to the battery pack and the data processor, and is configured to acquire a response voltage of the battery pack; The current acquisition module is connected to the battery pack and the data processor, and is configured to acquire a response current of the battery pack; The data processor is configured to obtain a response voltage and a response current.

8. The power battery online electrochemical impedance spectroscopy detection system according to claim 7, characterized in that: The battery pack includes a plurality of battery cells. The voltage acquisition module is connected to each of the battery cells. The voltage acquisition module is configured to acquire a response voltage of each of the battery cells.

9. The power battery online electrochemical impedance spectroscopy detection system according to claim 2, characterized in that: The data processor comprises: An impedance spectrum calculation module for calculating the real and imaginary parts of the impedance, wherein the impedance spectrum calculation module is connected to the signal collector; a drawing module for receiving the real part and the imaginary part of the impedance and drawing a Nyquist curve, wherein the drawing module is connected to the impedance spectrum calculation module; A storage module for storing the impedance and the corresponding Nyquist curve, wherein the storage module is connected to the impedance spectrum calculation module and the drawing module.

10. The power battery online electrochemical impedance spectroscopy detection system according to claim 1, characterized in that: The excitation switch is an NMOS tube or a PMOS tube.

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