CN106324355A - AC impedance test system and method for electrochemical device - Google Patents

Abstract

The invention provides an AC impedance testing system of an electrochemical device, comprising an electrochemical device, a control device, a DC regulating branch and a disturbance regulating branch connected in parallel with the DC regulating branch, the electrochemical device is connected to the control device; the DC regulating branch The circuit includes a first output load, the disturbance regulation branch includes a current disturbance device for generating a disturbance current and a second output load, and the control device is used to adjust the input current of the current disturbance device to a preset value after the current disturbance device is controlled to be turned on. Disturb the current, and calculate the AC impedance corresponding to the disturbance frequency of the preset disturbance current according to the output current and output voltage of the single piece of the electrochemical device to be tested. The invention also provides an AC impedance testing method of the electrochemical device. The AC impedance testing system and method of the electrochemical device of the present invention have simple circuit structure and strong versatility, and further improve the performance of the testing system.

Description

AC impedance testing system and method for electrochemical device

technical field

The invention relates to the technical field of electrochemical devices, in particular to an AC impedance testing system and method for electrochemical devices.

Background technique

Hydrogen-oxygen proton exchange membrane fuel cell (Proton Exchange Membrane Fuel Cell, referred to as PEMFC) is an electrochemical device that directly converts chemical energy into electrical energy. The energy conversion of traditional internal combustion engines is limited by the Carnot cycle, while hydrogen-oxygen proton exchange membrane fuel cells Energy conversion is not limited by the Carnot cycle, and theoretically its energy conversion efficiency is higher. Because the substances involved in the reaction are hydrogen and air, the reaction product is water, and no harmful emissions are produced, so it is favored by people and gradually used in backup power stations, transportation, and mobile power supplies.

The output characteristic of the proton exchange membrane fuel cell is DC, and its single-chip output voltage is less than 1V, typically 0.7V. The power is increased accordingly. A fuel cell monolith is composed of an anode gas diffusion layer (Gas Diffusion Layer, GDL for short), a membrane electrode assembly (Membrane Electrode Assemblies, MEA for short) and a cathode gas diffusion layer.

The fuel cell stack is the core component of the fuel cell power generation system. There are many accessory systems around the stack to assist the fuel cell stack to work, including air system, hydrogen system, cooling system, power regulation system, humidification system and control system, etc. . The air system is responsible for providing the stack with an appropriate amount of oxidant, that is, air, and the temperature, pressure and flow of the air entering the stack need to be adjusted according to the working conditions; the hydrogen system is responsible for supplying hydrogen to the stack, and the pressure of hydrogen entering the stack needs to be adjusted according to the working conditions and flow rate; the cooling system maintains the stack temperature at an appropriate level through coolant circulation to ensure the stable and reliable operation of the stack; the power regulation system makes the output characteristics of the fuel cell system It can meet the load demand; the humidification system is responsible for adjusting the humidity of the air entering the stack, too dry or too humid will have adverse effects on the proton exchange membrane and the stack, so it is necessary to control the humidity of the air entering the stack; the control system It is the "brain" of the entire fuel cell power generation system, especially to optimize the control of various subsystems around the stack, so that the stack is in the best working condition and ensure the long-term stable and reliable operation of the stack.

Figure 1 shows a typical fuel cell system. The ambient air is compressed by the air compressor and enters the radiator. After being cooled by the radiator, it enters the humidifier for humidification. After humidification, it enters the stack and undergoes an electrochemical reaction. The oxygen will chemically react with the hydrogen ions from the anode, produce water (gas or liquid) while outputting electric energy, and most of it flows out from the cathode air side, so the oxygen content in the cathode air after participating in the reaction decreases, and the water content ( Humidity) increases, and after the air at the stack outlet passes through the condenser to recover moisture, it is discharged into the environment through the flow control valve 2. Among them, the air system can control the air flow and air pressure entering the stack through the coordinated control of the air compressor and flow control valves 1 and 2, adjust the intake air temperature through the radiator, and control the intake air humidity through the humidifier.

According to the working principle and performance characteristics of PEMFC, because the water (gas or liquid) generated by the internal reaction of the stack needs to be taken out through the cathode reaction channel, if the generated liquid water is not removed in time, the generated water will block the flow channel, which is the so-called The phenomenon of water flooding will lead to the degradation of the performance of the stack and affect the use of the fuel cell. In order to improve the drainage capacity, it is necessary to increase the flow rate or velocity of the air in order to blow off the liquid water smoothly. At idle speed or light load, since the amount of water generated is relatively small, if the air flow rate is maintained at a high level, it is easy to dry up the water on the flow channel and the surface of the proton exchange membrane, resulting in the membrane being too dry and performance degradation; The small air flow rate is not easy to blow away the liquid water in the flow channel and cause flooding.

In the fuel cell control system, based on the existing sensor configuration, including the cathode and anode inlet temperature and pressure sensors, the cathode and anode outlet temperature and pressure sensors, and the cathode inlet and outlet humidity sensors, the lumped parameter model is usually used to analyze the internal workings of the fuel cell stack. However, due to the fact that the fuel cell stack is composed of many single pieces connected in series, and limited by the structure of the gas supply system of the stack, the air intake pressure, temperature, humidity and intake air composition of each fuel cell are different. , The difference in gas supply status and temperature of a single chip leads to the inconsistency of the single chip voltage. When the structure of the supply system is unreasonable and the number of single chips increases, the inconsistency of the single chip voltage becomes more obvious. Since it is impossible to observe the working status of a single fuel cell in real time, especially if it is impossible to timely and effectively judge whether a single piece is flooded or the membrane is dry, it is difficult to adjust the internal working status of the fuel cell by controlling the gas supply system and humidification system of the fuel cell. It is very detrimental to the improvement of the performance of the fuel cell system to avoid the occurrence of water flooding or membrane dryness of the local fuel cell single sheet.

However, with the advancement of science and technology, through continuous in-depth research, people have found that the performance characteristics of fuel cells can be studied in the form of equivalent circuits, and there is a certain correspondence between the working state of fuel cells and the impedance elements in the equivalent circuit . According to the relationship between the equivalent circuit of the fuel cell and the performance of the fuel cell, as well as the corresponding relationship between the resistors and capacitors of the equivalent circuit of the fuel cell and the states of different components of the fuel cell stack, the equivalent circuit of the fuel cell can be obtained in real time The change of the impedance value of the resistance element and the capacitance element in the medium can accurately predict the working state of the fuel cell single chip and the overall working state of the fuel cell stack.

In order to obtain the resistance and capacitance parameters in the fuel cell equivalent circuit, it is necessary to conduct AC impedance research. Currently, the commercialized AC impedance analysis equipment on the market costs more than RMB 100,000, and its operating voltage range and current range cannot meet the requirements. The wide range of application requirements of existing fuel cells, especially the number of single pieces of fuel cell stacks can vary from one to hundreds of pieces and the area of single pieces of fuel cells can vary from several square centimeters to hundreds of square centimeters. Although the frequency measurement range of commercial AC impedance analysis equipment is wide, according to the results of literature survey, the acceptable frequency band range is not as wide as described by these instruments and equipment when performing AC impedance analysis of fuel cells.

Contents of the invention

In view of the high cost and poor versatility of the above-mentioned commercial AC impedance analysis equipment, the purpose of the present invention is to provide an AC impedance testing system and method for electrochemical devices, the above-mentioned testing system is low in cost and high in versatility.

To achieve the above object, the present invention adopts the following technical solutions:

An AC impedance testing system for an electrochemical device, comprising an electrochemical device, a control device, a DC regulation branch, and a disturbance regulation branch connected in parallel with the DC regulation branch, the electrochemical device is connected to the control device;

The direct current regulation branch includes a first output load, the input end of the first output load is connected to the electrochemical device, the output end of the first output load is connected to the control device with a signal, and the control device monitoring the working state of the first output load;

The disturbance regulation branch includes a current disturbance device for generating a disturbance current and a second output load, the input terminal of the current disturbance device is connected to the electrochemical device, and the output terminal of the current disturbance device is connected to the first two output loads, and both the current disturbance device and the second output load are connected to the control device;

The control device is used to adjust the input current of the current disturbance device to a preset disturbance current after controlling the opening of the current disturbance device, and according to the output current and output voltage of the single piece of the electrochemical device to be tested Calculating the AC impedance corresponding to the disturbance frequency of the preset disturbance current.

In one of the embodiments, the control device includes a controller and a voltage inspection device for monitoring the output voltage of each single chip under test of the electrochemical device;

The voltage measurement terminals of each single chip of the electrochemical device are connected to the voltage inspection device, the voltage inspection device is connected to the controller, and the controller is used to select the single chip to be tested and control the The voltage inspection device collects the output voltage of the selected single chip to be tested.

In one of the embodiments, the voltage patrol device includes a single-chip gating module and a signal processing module connected to each single chip of the electrochemical device;

The single-chip gating module is used to collect the output voltage of the single-chip under test according to the control signal of the controller; The output voltage is sent to the controller.

In one of the embodiments, it also includes a first voltage detection device and a first current detection device for detecting the output current of the electrochemical device;

The input terminal of the first voltage detection device is connected to the output terminal of the electrochemical device, and the output terminal of the first voltage detection device is connected to the common terminal of the voltage patrol device and the controller; The first current detection device is arranged in series at the output end of the electrochemical device, and the first current detection device is connected to the common terminal of the voltage patrol device and the controller.

In one of the embodiments, the direct current regulation branch further includes a second current detection device for detecting the input current of the first output load, and the second current detection device is connected to the controller.

In one of the embodiments, the disturbance regulation branch further includes a third current detection device for detecting the input current of the current disturbance device, the third current detection device is connected to the controller, and the control The device is also used to adjust the time when the current disturbance device is turned on or off according to the input current of the current disturbance device detected by the third current detection device, so that the input current of the current disturbance device reaches the Preset disturbance current.

In one of the embodiments, the input current of the current disturbance device includes an AC disturbance current and a DC disturbance current, and the amplitude of the AC disturbance current is smaller than the amplitude of the DC disturbance current;

The control device is also used for adjusting the disturbance frequency and the disturbance amplitude of the AC disturbance current and the amplitude of the DC disturbance current to obtain the preset disturbance current.

In one of the embodiments, the disturbance regulation branch further includes a second voltage detection device for detecting the output voltage of the current disturbance device and a fourth current detection device for detecting the output current of the current disturbance device ;

Both the second voltage detection device and the fourth current detection device are connected to the controller, and the controller is used for adjusting the voltage of the second output load according to the output voltage and the output current of the current disturbance device voltage range or resistance value.

In one of the embodiments, the current disturbance device is a Boost DC/DC converter, a Buck DC/DC converter or a DC/AC converter.

The present invention also provides an AC impedance testing method of an electrochemical device, which is used in the above-mentioned AC impedance testing system of an electrochemical device, and the method includes the following steps:

Control the first output load to start, and the electrochemical device works normally;

Determine whether to perform AC impedance test; when it is determined to perform AC impedance test, perform the following steps:

controlling the activation of the current disturbance device and the second output load;

adjusting the voltage range or resistance value of the second output load;

adjusting the input current of the current disturbance device to a preset disturbance current;

Obtaining the output current and output voltage of the single chip to be tested of the electrochemical device;

calculating the AC impedance corresponding to the disturbance frequency of the preset disturbance current according to the output current and output voltage of the single chip to be tested;

changing the disturbance frequency of the preset disturbance current to obtain an updated preset disturbance current;

calculating the AC impedance corresponding to the updated disturbance frequency according to the output current and output voltage of the single chip to be tested;

According to a plurality of different perturbation frequencies and their corresponding AC impedances, an AC impedance spectrum of the electrochemical device is obtained.

In one embodiment, the method also includes:

Obtain the disturbance frequency and disturbance amplitude of the AC disturbance current in the disturbance current;

Obtain the magnitude of the DC disturbance current in the disturbance current;

Obtaining a preset disturbance current according to the disturbance frequency and the disturbance amplitude of the AC disturbance current and the magnitude of the DC disturbance current;

Adjusting the opening or closing time of the current disturbance device, and adjusting the input current of the current disturbance device to the preset disturbance current.

In one embodiment, the method further includes the steps of:

When it is determined that the AC impedance test is not to be performed, the first output load is controlled to be turned on, and the current disturbance device is controlled to be turned off.

Beneficial effects of the present invention:

In the AC impedance testing system and method of the electrochemical device of the present invention, the electrochemical device can work normally through the first output load adjustment, and when the current disturbance device is turned on, the current disturbance device is adjusted through the second output load and the current disturbance device. The input current makes the output current of the electrochemical device superimpose an AC disturbance current on the basis of the DC current, so that the detection of the AC impedance of the electrochemical device can be realized, and the above-mentioned circuit structure is simple and versatile, reducing the need for AC impedance testing. system cost. Moreover, the performance of the test system is further improved by relatively independently setting the first output load and the second output load.

Description of drawings

Fig. 1 is a system diagram of a proton exchange membrane fuel cell of an embodiment;

Fig. 2 is the equivalent circuit diagram of electrochemical device;

Fig. 3 is the AC impedance spectrogram of electrochemical device;

4 is a system diagram of an AC impedance testing system of an electrochemical device according to an embodiment of the present invention;

Fig. 5 is a circuit structure diagram of an embodiment of the current disturbance device in Fig. 4;

Fig. 6 is a circuit structure diagram of another embodiment of the current disturbance device in Fig. 4;

FIG. 7 is a schematic diagram of an embodiment of the voltage inspection device in FIG. 4;

Fig. 8 is a diagram of the input current and the corresponding voltage signal of the current disturbance device in the single-frequency AC impedance measurement mode;

FIG. 9 is a flow chart of an embodiment of an AC impedance testing method for an electrochemical device of the present invention.

detailed description

In order to make the technical solution of the present invention more clear, the AC impedance testing system and method of the electrochemical device of the present invention will be further described in detail below in conjunction with the accompanying drawings. It should be understood that the specific embodiments described here are only used to explain the present invention and not to limit the present invention. It should be noted that, in the case of no conflict, the embodiments in the present application and the features in the embodiments can be combined with each other.

As shown in FIG. 4, the AC impedance testing system of an electrochemical device 100 according to an embodiment of the present invention includes an electrochemical device 100, a control device, a DC regulating branch, a disturbance regulating branch connected in parallel with the DC regulating branch, a first The voltage detection device 500 and the first current detection device 600 . Wherein, the first voltage detecting device 500 may be a voltage sensor, and the first current detecting device 600 may be a current sensor or a current transformer or the like. The electrochemical device 100, the direct current regulation branch and the disturbance regulation branch are all connected to the control device.

Wherein, the electrochemical device 100 is connected to a control device, and the control device is used to control the working conditions of the electrochemical device 100 . Generally, the output voltage of the electrochemical device 100 is a DC voltage, and the output current is a DC current. Electrochemical device 100 may include one or more monoliths that generate electrical energy through chemical reactions. Each monolith includes a positive electrode, a negative electrode, and a dielectric separator disposed between the positive and negative electrodes. As shown in FIG. 2 , each monolithic performance characteristic of the electrochemical device 100 can be equivalent with an equivalent circuit, which includes the Nernst voltage E _Nernst , the anode electric double layer capacitance C _dl,A , and the anode resistance R _f,A , cathode electric double layer capacitance C _dl,CA , cathode resistance R _f,CA and proton exchange membrane resistance R _Ω . Among them, the anode electric double layer capacitance C _dl, A is connected in parallel with the anode resistance R _f,A to form an anode RC circuit, the cathode electric double layer capacitance C _dl,CA is connected in parallel with the cathode resistance R _f,CA to form a cathode RC circuit, and the Stern voltage E _Nernst , anode RC circuit, proton exchange membrane resistance R _Ω and cathode RC circuit are set in series.

3 is an AC impedance spectrum corresponding to each monolithic equivalent circuit of the electrochemical device 100, wherein the horizontal axis Z _re represents the real part of the impedance, and the vertical axis Z _im represents the imaginary part of the impedance: wherein,

${\mathrm{<span\; class="notranslate">\; Z</span>}}_{\mathrm{<span\; class="notranslate">\; f</span>}\mathrm{<span\; class="notranslate">\; C</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; \&omega;</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; \&Omega;</span>}}<span\; class="notranslate">\; +</span>\frac{{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; f</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; A</span>}}}{\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; j\&omega;R</span>}}_{\mathrm{<span\; class="notranslate">\; f</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; A</span>}}{\mathrm{<span\; class="notranslate">\; C</span>}}_{\mathrm{<span\; class="notranslate">\; d</span>}\mathrm{<span\; class="notranslate">\; l</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; A</span>}}}<span\; class="notranslate">\; +</span>\frac{{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; f</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; C</span>}\mathrm{<span\; class="notranslate">\; A</span>}}}{\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; j\&omega;R</span>}}_{\mathrm{<span\; class="notranslate">\; f</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; C</span>}\mathrm{<span\; class="notranslate">\; A</span>}}{\mathrm{<span\; class="notranslate">\; C</span>}}_{\mathrm{<span\; class="notranslate">\; d</span>}\mathrm{<span\; class="notranslate">\; l</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; C</span>}\mathrm{<span\; class="notranslate">\; A</span>}}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; )</span>$

$\underset{\mathrm{<span\; class="notranslate">\; \&omega;</span>}<span\; class="notranslate">\; \&Right\; Arrow;</span>\mathrm{<span\; class="notranslate">\; \&infin;</span>}}{\mathrm{<span\; class="notranslate">\; lim</span>}}{\mathrm{<span\; class="notranslate">\; Z</span>}}_{\mathrm{<span\; class="notranslate">\; f</span>}\mathrm{<span\; class="notranslate">\; C</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; \&omega;</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; \&Omega;</span>}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 2</span>}<span\; class="notranslate">\; )</span>$

Z _FC (0)＝R _Ω +R _f,A +R _f,CA ＝R _internal (3)

Wherein, Z _FC (ω) represents the single-chip AC impedance of the electrochemical device 100, ω represents the frequency of the AC disturbance current, j represents the imaginary number unit, and R _internal represents when the single-chip output signal of the electrochemical device 100 is a DC signal exhibited total internal resistance.

Therefore, according to FIG. 3 and the above formulas (1) to (3), it can be known that the working environment state of each element in the electrochemical device 100 can be judged by detecting each impedance in the above-mentioned equivalent circuit during the operation of the electrochemical device 100. (such as temperature, humidity, etc.), so as to dynamically adjust the above-mentioned working environment state, so as to improve the efficacy of the electrochemical device 100 . In this embodiment, the electrochemical device 100 may be a power battery such as a low-temperature proton exchange membrane fuel cell, a lithium ion battery, or a lithium iron phosphate battery. Of course, the electrochemical device 100 may also use a supercapacitor or the like.

The control device includes a controller 210 and a voltage inspection device 220 connected to the controller 210. In this embodiment, the controller 210 and the voltage inspection device 220 are connected through a bus, and the electrochemical device 100, the first output load 300, the current Both the disturbance device 410 and the second output load 420 are connected to the controller 210 . Wherein, the controller 210 is used to control the operation of the above-mentioned components. In this embodiment, the controller 210 may determine according to the type of the electrochemical device 100 . For example, the controller 210 may include a hydrogen system, an air system, a cooling system, a recovery system, a temperature and humidity detection system, and the like. In other embodiments, when the electrochemical device 100 is a lithium-ion battery pack, the controller 210 may be a lithium-ion battery management device.

The voltage patrol device 220 is connected to the electrochemical device 100 for monitoring the output voltage of each single chip of the electrochemical device 100 . As shown in Figure 7, the voltage inspection device 220 includes a single-chip gating module 221 and a signal processing module 222, and the voltage measurement terminals of each single chip of the electrochemical device 100 are connected to the single-chip gating module of the voltage inspection device 220 221 , the controller 210 is used to select a single chip to be tested, and the single chip gating module 221 is used to collect the output voltage of the selected single chip to be tested according to the control signal of the controller 210 . The signal processing module 222 is connected to the controller 210 , and is configured to transmit the acquired output voltages of a plurality of single chips under test to the controller 210 after collecting the output voltages of a certain number of single chips under test. Specifically, the signal processing module 222 transmits the detected output voltages of the multiple single chips to be tested to the controller 210 through the communication bus. The single-chip gating module 221 and the signal processing module 222 may be composed of electronic circuit devices.

In this embodiment, the voltage sampling rate of the voltage inspection device 220 is as high as tens of kilohertz, so the AC impedance test system of this embodiment can measure voltage signals in a wide frequency range, thereby improving the performance of the AC test impedance test system. versatility.

In other embodiments, the controller 210 may control the voltage patrol device 220 to simultaneously collect the output voltages of multiple single chips. For example, the single-chip gating module can gate one or more single-chips to be tested according to the control signal of the controller 210, and the voltage patrol device 220 can realize synchronous sampling of the output voltage of each single-chip to be tested, thus improving electrochemical performance. AC impedance test efficiency of device 100 .

The DC regulation branch includes a first output load 300 and a second current detection device 310, the input end of the first output load 300 is connected to the electrochemical device 100, and the output end of the first output load 300 is connected to the control device signal, specifically, The output terminal of the first output load 300 is connected with the controller 210 for signal, and the controller 210 is used for monitoring the working state of the first output load, and can make the electrochemical device 100 output DC current by adjusting the first output load 300 . In this embodiment, the first output load 300 may be an electronic load or a motor. When the current disturbance device 410 is turned off, the controller 210 controls the first output load 300 to start, so that the electrochemical device 100 and the first output load 300 form a loop, so that the current disturbance device 410 can work normally. At this time, the electrochemical device 100 can be tested under various working conditions, and the voltage inspection device 220 can be controlled to monitor the output voltage of each single chip of the electrochemical device 100 .

The second current detecting device 310 is arranged at the input end of the first output load 300, and is used for detecting the input current of the first output load 300, and the second current detecting device 310 is connected to the controller 210, and the detected first output load The input current of 300 is sent to the controller 210 . Wherein, the second current detection device 310 may be a current sensor or a current transformer.

The disturbance regulation branch is set in parallel with the DC regulation branch, and the disturbance regulation branch is used to generate a disturbance current, including a current disturbance device 410 and a second output load 420, the input end of the current disturbance device 410 is connected to the electrochemical device 100, and the current disturbance The output end of the device 410 is connected to the second output load 420 , and both the current disturbance device 410 and the second output load 420 are connected to the control device, specifically, the current disturbance device 410 and the second output load 420 are both connected to the controller 210 . The controller 210 can control the opening or closing of the current disturbance device 410, and can adjust the input current of the current disturbance device 410 to a preset disturbance current by controlling the opening or closing time of the current disturbance device 410, and can adjust the AC disturbance The disturbance amplitude and disturbance frequency of the current are used to adjust the preset disturbance frequency, so as to realize the adjustment of the input current of the current disturbance device 410, so that the output current of the electrochemical device 100 includes an AC disturbance current, so as to realize the regulation of the electrochemical device 100 AC impedance test. At this time, the output voltage of the electrochemical device 100 will also generate a signal corresponding to the voltage corresponding to the AC disturbance current, wherein, the relationship between the input current of the current disturbance device 410 and the corresponding voltage signal in the single-frequency AC impedance measurement mode is shown in FIG. 8 Show.

Meanwhile, the controller 210 is also used to adjust the output voltage or resistance value of the second output load 420 so that the second output load 420 matches the output of the current disturbance device 410 to further control the input current of the current disturbance device 410 . The performance of the test system is further improved by relatively independently setting the first output load 300 and the second output load 420 . When the current disturbance device 410 is turned on, the input current of the disturbance regulation branch is the sum of the AC disturbance current and the DC disturbance current, for details, please refer to the description below.

Wherein, the current disturbance device 410 may be a Boost DC/DC converter, a Buck DC/DC converter or a DC/AC converter. The controller 210 can control the current disturbance device 410 to be turned on or off by controlling the switching device in the converter to be turned on or off. The second output load 420 can be a resistive load or an electronic load.

Further, the input terminal of the first voltage detection device 500 is connected to the output terminal of the electrochemical device 100, and the output terminal of the first voltage detection device 500 is connected to the common terminal of the voltage patrol device 220 and the controller 210, as shown in FIG. 4 As shown, the output terminal of the first voltage detection device 500 is connected to the connection line between the voltage inspection device 220 and the controller 210, so that both the controller 210 and the voltage inspection device 220 can obtain the waiting voltage through the first voltage detection device 500. Measuring the output voltage of a single chip simplifies the circuit structure and is easy to use. The first voltage detection device 500 may be a voltage sensor.

The first current detection device 600 is connected to the output end of the electrochemical device 100, and the first current detection device 600 is connected to the control device, specifically, the first current detection device 600 is connected to the voltage patrol device 220 and the controller The common terminal of 210, as shown in FIG. The first current detection device 600 may be a current sensor or a current transformer, which is used to detect the output current of each single piece of the electrochemical device 100 to be tested, and transmit the detected output current of the electrochemical device 100 to the control device.

The controller 210 is also used to calculate the AC impedance corresponding to the disturbance frequency of the current AC disturbance current according to the output current and output voltage of each single chip under test of the electrochemical device 100 after the current disturbance device 410 is turned on. Wherein, the output current of the electrochemical device 100 can be obtained by the first current detection device 600 , and the output voltage of the electrochemical device 100 can be obtained by the first voltage detection device 500 .

Further, both the disturbance frequency and the disturbance amplitude of the AC disturbance current are controllable values, and the controller 210 can adjust the disturbance frequency of the AC disturbance current and determine the disturbance amplitude corresponding to the disturbance frequency, so as to determine according to the disturbance frequency and the disturbance amplitude Preset AC disturbance current. The controller 210 is also used to change the disturbance amplitude and frequency of the AC disturbance current, update the AC disturbance current, and calculate the output current and output power of the electrochemical device 100 corresponding to the updated AC disturbance current corresponding to the updated disturbance frequency. AC impedance to obtain an AC impedance spectrum of the electrochemical device 100 . In this way, by changing the disturbance frequency of the AC disturbance current and measuring the AC impedance values of the electrochemical device 100 at different disturbance frequencies, a spectrum diagram of the AC impedance can be drawn. The above circuit has a simple structure and strong versatility, and reduces the cost of the AC impedance testing system.

In one embodiment, the disturbance regulation branch further includes a third current detection device 430 , a fourth current detection device 440 and a second voltage detection device 430 . Wherein, the third current detection device 430 is arranged at the input end of the current disturbance device 410 , and is used to detect the input current of the current disturbance device 410 in real time. The third current detection device 430 is connected to the controller 210, the controller 210 can adjust the input current of the current disturbance device 410 according to the current signal detected by the third current detection device 430, specifically, the controller 210 can The current signal detected at 430 adjusts the on or off time of the current disturbance device 410 so that the input current of the current disturbance device 410 reaches a preset disturbance current. When the current disturbance device 410 is turned on, the input current of the current disturbance device 410 includes an AC disturbance current and a DC disturbance current, that is

Wherein, I represents the input current of the current disturbance device 410, I ₁ represents the DC disturbance current, I ₂ represents the AC disturbance current, A represents the disturbance amplitude of the AC disturbance current, f represents the disturbance frequency of the AC disturbance current, Indicates the initial phase angle of the AC disturbance current, and t indicates the time.

The disturbance frequency of the AC disturbance current can be a single frequency or multiple frequencies. When the disturbance frequency of the AC disturbance current is multi-frequency, the calculation method of the AC disturbance current _I2 is as follows:

Among them, A ₁ and are the disturbance amplitude and initial phase corresponding to the disturbance frequency f ₁ , A ₂ and are the disturbance amplitude and initial phase corresponding to the disturbance frequency f ₂ , A ₁ and are the disturbance amplitude and initial phase corresponding to the disturbance frequency f ₁ , A _N and are the disturbance amplitude and initial phase corresponding to the disturbance frequency f _N , respectively. _In this embodiment, the disturbance amplitude and disturbance frequency of the AC disturbance current I at any frequency can be set by the controller 210, that is, the controller 210 can be used to realize the adjustment of the disturbance amplitude and disturbance frequency of the AC disturbance current. The online adjustment mainly depends on the requirements of the object to which the current disturbance device 410 is applied. Therefore, when the AC disturbance current has multiple frequencies, the controller 210 first determines the amplitude and initial phase corresponding to each disturbance frequency, and then calculates and obtains the AC disturbance current I ₂ according to the above formula.

Further, when the current disturbance device 410 adopts a DC/DC converter or a DC/AC converter, the amplitude of the AC disturbance current is smaller than the amplitude of the DC disturbance current, ensuring that the input current of the current disturbance device 410 is greater than 0, so as to ensure that the current The perturbation device 410 can work normally. When the AC disturbance current has multiple frequencies, the amplitude of the AC disturbance current at each frequency should be smaller than the amplitude of the DC disturbance current, that is, the maximum amplitude of the AC disturbance current should be smaller than the amplitude of the DC disturbance current to ensure that the current The perturbation device 410 can work normally.

Both the second voltage detection device 430 and the fourth current detection device 440 are placed at the output end of the current disturbance device 410, specifically, the second voltage detection device 430 and the fourth current detection device 440 are both placed at the current disturbance device 410 and the second Between the output loads 420 , both the second voltage detection device 430 and the fourth current detection device 440 are connected to the controller 210 . The second voltage detection device 430 is used to detect the output voltage of the current disturbance device 410 (ie, the input voltage of the second output load 420 ), and transmit the detected output voltage of the current disturbance device 410 to the controller 210 . The fourth current detection device 440 is used to detect the output current of the current disturbance device 410 (ie the input voltage of the second output load 420 ), and transmit the detected output current of the current disturbance device 410 to the controller 210 . In this embodiment, the second voltage detection device 430 may be a voltage sensor, and the third current detection device 430 and the fourth current detection device 440 may be current sensors or current transformers.

The controller 210 adjusts the output characteristics of the current disturbance device 410 according to the output current and output voltage of the current disturbance device 410 , and mainly adjusts the output voltage of the current disturbance device 410 . Then, the controller 210 can make the second output load 420 match the output of the current disturbance device 410 by adjusting the voltage range or resistance value of the second output load 420 . Therefore, the input current of the current disturbance device 410 can be controlled according to the detection values of the third current detection device 430 , the fourth current detection device 440 and the second voltage detection device 430 .

In one embodiment, the current disturbance device 410 includes a switching device, and the controller 210 is used to control the switching device to be turned on or off, so as to control the current disturbance device 410 to be turned on or off, and can control the switching device to be turned on or off time, so that the input current of the current disturbance device 410 reaches the preset disturbance current.

As shown in FIG. 5 , the current disturbance device 410 is a Boost DC/DC converter, including an inductor L1, a diode D1, a switching device G1 and a capacitor C1, wherein the switching device G1 can be an IGBT (Insulated Gate Bipolar Transistor, insulated gate bipolar transistor), MOS tube (metal-oxide semiconductor, field effect transistor) or BJT tube (Bipolar Junction Transistor, bipolar junction transistor) and so on. One end of the inductor L1 is connected to the positive pole of the input power supply, the other end of the inductor L1 is connected to the anode of the diode D1, the cathode of the diode D1 is connected to the positive pole of the output power supply, and the input power supply and the output power supply have a common negative pole. The collector of the switching device is connected to the common terminal between the inductor L1 and the diode D1, the emitter of the switching device G1 is connected to the negative pole of the input power supply, the gate of the switching device G1 is connected to the controller 210, and the controller 210 controls the switching device G1 on or off. The capacitor C1 is connected between the positive pole and the negative pole of the output power supply, that is, one end of the capacitor C1 is connected to the cathode of the diode D1, and the other end of the capacitor C1 is connected to the negative pole of the output power supply.

When the switching device G1 is turned on, the current generated by the input power flows through the inductor L1. According to the physical characteristics of the inductor, the current flowing through the inductor L1 increases linearly, and the electric energy is stored in the inductor L1. The inductor L1 and the switching device G1 form a conduction loop. , at this time, the anode of the diode D1 is connected between the negative pole of the input power supply and the positive pole of the output power supply, and the diode D1 is reversely cut off. When the switching device G1 changes from on to off, according to the physical characteristics of the inductor, the current flowing through the inductor L1 cannot produce a sudden change, thereby generating an electromotive force. The direction of the electromotive force is the same as that of the input power supply, and the electric energy stored in the inductor L1 Continuously releasing, charging the capacitor C1 through the diode D1 and providing energy to the second output load 420 , at this time, the inductor L1 , the diode D1 , the capacitor C1 and the second output load 420 form a loop. When the switching device G1 is periodically controlled to be turned on and off, energy can be transferred from the input power supply to the output power supply. The controller 210 can generate an AC disturbance signal by controlling the on or off state of the switching device G1 at different times.

As shown in Figure 6, the current disturbance device 410 can also use a Buck step-down DC/DC converter, including a switching device G2, an inductor L2, a diode D2 and a capacitor C2, wherein the switching device G2 can be an IGBT tube (Insulated Gate Bipolar Transistor , insulated gate bipolar transistor), MOS tube (metal-oxide semiconductor, field effect transistor) or BJT tube (Bipolar Junction Transistor, bipolar junction transistor) and so on. The gate of the switching device G2 is connected to the controller 210, the collector of the switching device G2 is connected to the positive pole of the input power supply, the emitter of the switching device G2 is connected in series with the inductor L2 to the positive pole of the output power supply, and the output power supply and the input power supply have a common negative pole. The anode of the diode D2 is connected to the cathode of the output power supply, and the cathode of the diode D2 is connected to the corresponding common terminal between the emitter of the switching device G2 and the inductor L2. The capacitor C2 is connected between the positive pole and the negative pole of the output power supply, that is, one end of the capacitor C2 is connected to the inductor L1, and the other end of the capacitor C2 is connected to the positive pole of the diode D2.

When the controller 210 controls the switching device G2 to be turned on, the cathode of the diode D2 is connected to the anode of the input power, the anode of the diode D2 is connected to the cathode of the input power, and the diode D2 is turned off. The input power charges the inductor L2 through the switching device G2. When the controller 210 controls the switching device G2 to be turned off, the inductor L2 charges the capacitor C2, thereby realizing the transmission of the input power to the output power.

The working principle of the AC impedance testing system of the electrochemical device 100 in this embodiment is as follows:

1) Non-AC impedance test mode:

When the controller 210 determines that the AC impedance analysis is not to be performed, the controller 210 controls the current disturbance device 410 to be turned off. At this time, the controller 210 first adjusts the working conditions of the electrochemical device 100 so that the electrochemical device 100 establishes an open circuit voltage, and then controls the first output load 300 to start, so that the electrochemical device 100 starts to work normally, and the electrochemical device 100 Both output voltage and output current are DC signals. At the same time, the voltage of each single chip of the electrochemical device 100 is monitored by the voltage inspection device 220, and the output current of the electrochemical device 100 is monitored by the first current detection device 600, so that the monitoring of each chip of the electrochemical device 100 can be realized. Tested under various operating conditions.

2) AC impedance test mode

When the controller 210 determines to perform AC impedance analysis, the controller 210 controls the current disturbance device 410 and the second output load 420 to start. The controller 210 adjusts the second output load 420 to an appropriate voltage range or resistance value. The controller 210 obtains a preset disturbance current by adjusting the AC disturbance current and the DC disturbance current of the disturbance current. Specifically, the controller 210 selects the AC disturbance The disturbance frequency of the current, and determine the disturbance amplitude corresponding to the disturbance frequency, obtain the preset disturbance current, and adjust the input current of the current disturbance device 410 to the preset disturbance current, wherein the input current of the current disturbance device 410 is equal to the AC disturbance The sum of the current and the DC disturbance current adjusts the output of the second output load 420 so that the magnitude of the AC disturbance current is always smaller than the magnitude of the DC disturbance current.

In this way, the output current of the electrochemical device 100 includes an AC disturbance current, and the output voltage of the electrochemical device 100 will also generate a voltage response signal corresponding to the AC disturbance current. At this time, the output voltage of the selected single chip under test of the electrochemical device 100 is detected by the first voltage detection device 500 , and the output current of the single chip under test is detected synchronously by the first current detection device 600 . After collecting the output voltage and output current of a certain number of single chips to be tested, the single chip inspection device transmits the above output voltages and output currents to the controller 210 .

The controller 210 performs signal processing on the collected output voltages and output currents of multiple single chips to be tested, and calculates the AC impedance at the disturbance frequency of the current AC disturbance current. Afterwards, the controller 210 changes the disturbance frequency and the disturbance amplitude of the AC disturbance current to obtain an updated AC disturbance current, and calculates the AC impedance at the disturbance frequency of the updated AC disturbance current according to the above method. Through the AC impedance corresponding to multiple different disturbance frequencies, the frequency spectrum of the AC impedance can be drawn. Afterwards, the controller 210 controls the current disturbance device 410 to turn off.

In addition, as shown in FIG. 9 , an embodiment of the present invention also provides an AC impedance testing method of an electrochemical device, which is used in the AC impedance testing system of the above electrochemical device, including the following steps:

S100. Control the start of the first output load to make the electrochemical device work normally; in this embodiment, the electrochemical device can output a direct current by adjusting the first output load.

S200. Determine whether to perform an AC impedance test; wherein, the controller can determine whether to perform an AC impedance test according to whether a test trigger signal is received, and the controller can also determine whether to perform an AC impedance test according to the current working conditions of the AC impedance system. For example, when the When the working condition of the AC impedance testing system reaches the preset working condition, the controller controls the testing system to perform the AC impedance test; otherwise, the AC impedance test is not performed.

When it is determined that the AC impedance test needs to be performed, that is, when the AC impedance test system is in the AC impedance test mode, the following steps are performed:

S300. Control the current disturbance device and start the second output load; that is, when an AC impedance test is required, the disturbance regulation branch is connected to the output end of the electrochemical device, so that a disturbance current can be superimposed on the output end of the electrochemical device to realize AC impedance test. After the current disturbance device and the second output load are activated, perform the AC impedance test as follows:

S400. Adjust the voltage range or resistance value of the second output load; make the voltage range or resistance value of the second output load adapt to the output of the current disturbance device by adjusting the second output load. In this embodiment, the output voltage of the current disturbance device can be controlled by the detection values of the second voltage detection device and the fourth current detection device disposed between the second output load and the current disturbance device.

S500. Adjust the input current of the current disturbance device to the preset disturbance current; specifically, when the input current of the current disturbance device does not reach the preset disturbance current, the controller can regulate the conduction or cut-off of the switching device in the current disturbance device time, so that the input current of the current disturbance device reaches the preset disturbance current.

Among them, the preset disturbance current can be obtained through online adjustment, as follows:

Obtain the disturbance frequency and disturbance amplitude of the AC disturbance current in the disturbance current; wherein the controller first determines the disturbance frequency of the AC disturbance current, and then determines the disturbance amplitude corresponding to the above disturbance frequency, thereby obtaining the current AC disturbance current. When the disturbance frequency is multi-frequency, each disturbance frequency and its corresponding disturbance amplitude are firstly determined, and then a preset disturbance current is formed by superimposing each sub-disturbance current.

Obtain the magnitude of the DC disturbance current in the disturbance current; that is, the DC disturbance current in the disturbance current can be set online.

The preset disturbance current is obtained according to the disturbance frequency and the disturbance amplitude of the AC disturbance current and the magnitude of the DC disturbance current. in,

Among them, I represents the preset disturbance current, I ₁ represents the DC disturbance current, I ₂ represents the AC disturbance current, A represents the disturbance amplitude of the AC disturbance current, f represents the disturbance frequency of the AC disturbance current, Indicates the initial phase angle of the AC disturbance current, and t indicates the time.

S600. Obtain the output current and output voltage of the single chip to be tested in the electrochemical device; in this embodiment, the output voltage of the single chip to be tested can be obtained through the first voltage detection device and the voltage inspection device, and the Synchronously obtain the output current of the single chip under test.

S700. Calculate the AC impedance corresponding to the disturbance frequency of the preset disturbance current according to the output current and output voltage of the single chip to be tested;

S800. Change the disturbance frequency of the preset disturbance current to obtain an updated preset disturbance current; wherein, the disturbance amplitude and disturbance frequency of the AC disturbance current are controllable and can be adjusted online through a controller.

S900. Calculate the AC impedance corresponding to the updated disturbance frequency according to the output current and output voltage of the single chip to be tested; that is, after step S800, return to step S500, and repeat steps S500 to S800 until multiple different disturbances are obtained Frequency and its corresponding AC impedance. For the specific implementation manner, refer to the above description.

S1000. Obtain an AC impedance spectrum of the electrochemical device according to a plurality of different disturbance frequencies and their corresponding AC impedances. In this way, the frequency spectrum of the AC impedance can be drawn by changing the disturbance frequency of the AC disturbance current and measuring the AC impedance value of the electrochemical device at different disturbance frequencies. The above circuit has a simple structure and strong versatility, and reduces the cost of the AC impedance testing system.

In one embodiment, the method also includes the steps of:

When the controller determines that no AC impedance test is required, that is, when the AC impedance test system is working in a non-AC impedance test mode, step S1001 is performed to control the current disturbance device to be turned off, and control the first output load to be in the open state, and at the same time control the second An output load output power for the electrochemical device to work normally. Specifically, when the current disturbance device is turned off, the controller starts up by controlling the first output load, so that the electrochemical device forms a loop with the first output load, so that the current disturbance device can work normally. Therefore, the electrochemical device can be tested in various working conditions, and the voltage inspection device can be controlled to monitor the output voltage of each single chip of the electrochemical device.

Wherein, the AC impedance testing method in this embodiment is consistent with the working principle of the AC impedance testing system in the above-mentioned embodiments, and the specific execution process can refer to the description above.

In the AC impedance testing system and method of the electrochemical device of the present invention, the electrochemical device can work normally through the first output load adjustment, and when the current disturbance device is turned on, the current disturbance device is adjusted through the second output load and the current disturbance device. The input current makes the output current of the electrochemical device superimpose an AC disturbance current on the basis of the DC current, so that the detection of the AC impedance of the electrochemical device can be realized, and the above-mentioned circuit structure is simple and versatile, reducing the need for AC impedance testing. system cost. Moreover, the performance of the test system is further improved by relatively independently setting the first output load and the second output load.

Those of ordinary skill in the art can understand that all or part of the processes in the methods of the above embodiments can be implemented through computer programs to instruct related hardware, and the programs can be stored in a computer-readable storage medium. During execution, it may include the processes of the embodiments of the above-mentioned methods. Wherein, the storage medium may be a magnetic disk, an optical disk, a read-only memory (Read-Only Memory, ROM) or a random access memory (Random Access Memory, RAM) and the like.

The above-mentioned embodiments only express several implementation modes of the present invention, and the descriptions thereof are relatively specific and detailed, but should not be construed as limiting the patent scope of the present invention. It should be pointed out that those skilled in the art can make several modifications and improvements without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent for the present invention should be based on the appended claims.

Claims (12)

1. An AC impedance testing system of an electrochemical device, characterized in that it comprises an electrochemical device, a control device, a direct current regulation branch and a disturbance regulation branch connected in parallel with the direct current regulation branch, and the electrochemical device is connected said control device; The direct current regulation branch includes a first output load, the input end of the first output load is connected to the electrochemical device, the output end of the first output load is connected to the control device with a signal, and the control device for monitoring the working state of the first output load; The disturbance regulation branch includes a current disturbance device for generating a disturbance current and a second output load, the input terminal of the current disturbance device is connected to the electrochemical device, and the output terminal of the current disturbance device is connected to the first two output loads, and both the current disturbance device and the second output load are connected to the control device; The control device is used to adjust the input current of the current disturbance device to a preset disturbance current after controlling the opening of the current disturbance device, and according to the output current and output voltage of the single piece of the electrochemical device to be tested Calculating the AC impedance corresponding to the disturbance frequency of the preset disturbance current. 2. The AC impedance testing system of an electrochemical device according to claim 1, wherein the control device includes a controller and a voltage controller for monitoring the output voltage of each single chip to be tested of the electrochemical device. inspection device; The voltage measurement terminals of each single chip of the electrochemical device are connected to the voltage inspection device, the voltage inspection device is connected to the controller, and the controller is used to select the single chip to be tested and control the The voltage inspection device collects the output voltage of the selected single chip to be tested. 3. The AC impedance testing system of the electrochemical device according to claim 2, wherein the voltage inspection device includes a single-chip gating module and a signal processing module connected to each single chip of the electrochemical device ; The single-chip gating module is used to collect the output voltage of the single-chip under test according to the control signal of the controller; The output voltage is sent to the controller. 4. The AC impedance testing system of an electrochemical device according to claim 2, further comprising a first voltage detection device and a first current detection device for detecting the output current of the electrochemical device; The input terminal of the first voltage detection device is connected to the output terminal of the electrochemical device, and the output terminal of the first voltage detection device is connected to the common terminal of the voltage patrol device and the controller; The first current detection device is arranged in series at the output end of the electrochemical device, and the first current detection device is connected to the common terminal of the voltage patrol device and the controller. 5. The AC impedance testing system of an electrochemical device according to claim 2, wherein the DC regulation branch further comprises a second current detection device for detecting the input current of the first output load, the The second current detection device is connected to the controller. 6. The AC impedance testing system of an electrochemical device according to claim 2, wherein the disturbance regulation branch further comprises a third current detection device for detecting the input current of the current disturbance device, the The third current detection device is connected to the controller, and the controller is further configured to adjust the current disturbance device to be turned on or off according to the input current of the current disturbance device detected by the third current detection device. time, so that the input current of the current disturbance device reaches the preset disturbance current. 7. The AC impedance testing system of an electrochemical device according to claim 6, wherein the input current of the current disturbance device includes an AC disturbance current and a DC disturbance current, and the amplitude of the AC disturbance current is smaller than the Amplitude of DC disturbance current; The control device is also used for adjusting the disturbance frequency and the disturbance amplitude of the AC disturbance current and the amplitude of the DC disturbance current to obtain the preset disturbance current. 8. The AC impedance testing system of an electrochemical device according to claim 6, wherein the disturbance regulation branch further comprises a second voltage detection device for detecting the output voltage of the current disturbance device and a second voltage detection device for detecting the output voltage of the current disturbance device. fourth current sensing means for sensing the output current of said current disturbance means; Both the second voltage detection device and the fourth current detection device are connected to the controller, and the controller is used for adjusting the voltage of the second output load according to the output voltage and the output current of the current disturbance device voltage range or resistance value. 9. The AC impedance testing system of the electrochemical device according to claim 1, wherein the current perturbation device is a Boost step-up DC/DC converter, a Buck type step-down DC/DC converter or a DC/DC converter. AC converter. 10. An AC impedance testing method of an electrochemical device, characterized in that, it is used for the AC impedance testing system of the electrochemical device according to claim 1, said method comprising the steps of: Control the first output load to start, and the electrochemical device works normally; Determine whether to perform an AC impedance test; When it is judged to carry out the AC impedance test, perform the following steps: controlling the activation of the current disturbance device and the second output load; adjusting the voltage range or resistance value of the second output load; adjusting the input current of the current disturbance device to a preset disturbance current; Obtaining the output current and output voltage of the single chip to be tested of the electrochemical device; calculating the AC impedance corresponding to the disturbance frequency of the preset disturbance current according to the output current and output voltage of the single chip to be tested; changing the disturbance frequency of the preset disturbance current to obtain an updated preset disturbance current; calculating the AC impedance corresponding to the updated disturbance frequency according to the output current and output voltage of the single chip to be tested; According to a plurality of different perturbation frequencies and their corresponding AC impedances, an AC impedance spectrum of the electrochemical device is obtained. 11. the AC impedance testing method of electrochemical device according to claim 10, is characterized in that, described method also comprises: Obtain the disturbance frequency and disturbance amplitude of the AC disturbance current in the disturbance current; Obtain the magnitude of the DC disturbance current in the disturbance current; Obtaining a preset disturbance current according to the disturbance frequency and the disturbance amplitude of the AC disturbance current and the magnitude of the DC disturbance current; Adjusting the opening or closing time of the current disturbance device, and adjusting the input current of the current disturbance device to the preset disturbance current. 12. AC impedance testing method according to claim 10, is characterized in that, described method also comprises the steps: When it is determined that the AC impedance test is not to be performed, the first output load is controlled to be turned on, and the current disturbance device is controlled to be turned off.