Detection circuit, fuel cell detection device, and fuel cell system

Abstract

The utility model provides a single cell detection circuit, a fuel cell detection device and a fuel cell system, and the circuit comprises a first detection interface which is used for connecting a single cell negative electrode of a first single cell, and a second detection interface which is used for connecting a single cell positive electrode of the first single cell; the first module is connected between the second detection interface and the detection reference end, the second module is connected between the first detection interface and the detection reference end, the voltage module is connected between the first detection interface and the detection reference end, and the first measurement circuit is connected between the second detection interface and the first detection interface; based on the single body detection circuit, the first measurement circuit can generate measurement results in different ranges for different types of faults, so that corresponding processing measures can be taken according to the fault types.

Description

Technical Field

[0001] This application relates to the technical field of fuel cells, specifically a detection circuit, a fuel cell detection device based on the single-unit detection circuit, and a fuel cell system based on the fuel cell detection device. Background Technology

[0002] Fuel cell stacks, also known as fuel cell stacks, are made up of two or more fuel cell cells stacked together. They are widely used in energy storage and new energy vehicles. In order to improve the safety of fuel cell stacks, they need to be tested.

[0003] A related technology, such as Figure 1 As shown, the fuel cell system includes a stack 100, with first cell 110 stacked on the negative terminal of the stack 100. The negative terminal of the first cell 110, the negative terminal of the stack 100, and the ground terminal of the stack 100 are interconnected. A voltage measurement circuit 101 is connected to both ends of the first cell 110 to detect the voltage of the first cell 110.

[0004] In this related technology, in the first type of fault, there may be water accumulation in the first battery cell 110. In the face of this fault, the fuel cell stack 100 needs to be shut down and restarted after the water is dried. In the second type of fault, the voltage measurement circuit 101 may be disconnected from the first battery cell 110. In the face of this fault, the fuel cell stack 100 can continue to operate until conditions permit for inspection or maintenance. The above two faults should be dealt with by different means. However, the voltage measurement circuit 101 may have the same or similar measurement values ​​for the above two faults, which makes it impossible to determine the fault type in time, reduces the safety of the use of the fuel cell stack 100, and affects the efficiency of the fuel cell system. Utility Model Content

[0005] This application provides a detection circuit, a fuel cell detection device, and a fuel cell system, which are designed to detect the cells in the fuel cell stack and thus distinguish the types of faults.

[0006] A first aspect of this application provides a detection circuit for detecting a grounded first battery cell in a battery stack. The detection circuit includes: a first detection interface for connecting to the negative terminal of the first battery cell; a second detection interface for connecting to the positive terminal of the first battery cell; a detection reference terminal for providing a zero-point reference point for the detection circuit; a first module connected between the second detection interface and the detection reference terminal, the equivalent resistance of the first module being greater than or equal to 100kΩ; a second module connected between the first detection interface and the detection reference terminal, the equivalent resistance of the second module being greater than or equal to 100kΩ; a voltage module for outputting a voltage signal, the positive output terminal of the voltage module being connected to the first detection interface, the negative output terminal of the voltage module being connected to the detection reference terminal, and the output voltage of the voltage module being greater than twice the output voltage of the first battery cell; and a first measurement circuit for measuring the voltage between the first detection interface and the second detection interface, the first measurement circuit being connected between the second detection interface and the first detection interface.

[0007] In this embodiment, if the normal output voltage of the first battery cell is U1 and the output voltage of the voltage module is U2, then the output voltage of the first battery cell in the water accumulation state is greater than -U1 and less than 0V. If the connection line between the first detection interface and the first battery cell is disconnected, the measurement result of the first measurement circuit is U1-U2. If the connection line between the second detection interface and the first battery cell is disconnected, the measurement result of the first measurement circuit is -U2. Since the output voltage of the voltage module is greater than twice the output voltage of the first battery cell, -U1, U1-U2, and -U2 will not overlap. The fault type of the first battery cell can be determined according to the measurement result of the first measurement circuit, so as to take corresponding treatment measures according to the fault type. In addition, the equivalent resistance of the first module is greater than or equal to 100kΩ, which can reduce the current flowing through the first module and thus reduce the energy consumption of the detection circuit.

[0008] In some examples of the first aspect of the embodiments of this application, the second module includes a second measurement circuit, which is connected between the first detection interface and the detection reference terminal, and is used to measure the output voltage of the voltage module.

[0009] In this embodiment, compared to a pure resistor, the second measurement circuit can measure the output voltage of the voltage module. Based on the measurement results of the first and second measurement circuits, the real-time results of -U1, U1-U2, and -U2 can be determined, thereby improving the accuracy of fault identification of the first battery cell.

[0010] In some examples of the first aspect of the embodiments of this application, the detection circuit further includes a unidirectional diode, the negative terminal of which is connected to a detection reference terminal; the negative output terminal of the voltage module is connected to the detection reference terminal, including the negative output terminal of the voltage module being connected to the positive terminal of the unidirectional diode; and a second module is connected between the first detection interface and the detection reference terminal, including the second module being connected to the positive terminal of the unidirectional diode.

[0011] In this embodiment, since the negative terminal of the unidirectional diode is connected to the detection reference terminal, the negative output terminal of the voltage module is connected to the positive terminal of the unidirectional diode, and the second module is connected to the positive terminal of the unidirectional diode, if the detection reference terminal of the detection circuit is connected to the ground terminal of the battery stack, or if the detection reference terminal of the detection circuit fluctuates, or if the ground terminal of the battery stack fluctuates, the unidirectional diode can reduce the impact of the connection or fluctuation on the measurement of the first measurement circuit, thereby improving the accuracy of fault identification of the first battery cell.

[0012] In some examples of the first aspect of the embodiments of this application, the detection circuit further includes a third module. One end of the third module is connected to the second detection interface through a switch module, and the other end of the third module is connected to the first detection interface. The equivalent resistance of the third module is less than or equal to 1kΩ. When the switch module is in a closed-circuit state, the third module is connected in series with the first battery cell.

[0013] In this embodiment, when the switch module is in an open-circuit state, the first measurement circuit can measure the voltage between the first detection interface and the second detection interface. When the switch module is in a closed-circuit state, the first measurement circuit can measure the voltage allocated by the third module. Based on the difference between the two measurement results and the resistance value of the third module, the equivalent resistance between the detection circuit and the first battery cell can be determined, and the connection between the detection circuit and the first battery cell can be judged.

[0014] In some examples of the first aspect of the embodiments of this application, the output voltage of the voltage module is greater than four times the output voltage of the first battery cell.

[0015] In this embodiment, since the output voltage of the voltage module is greater than four times the output voltage of the first battery cell, there will be a difference of U1 between -U1, U1-U2, and -U2. Even if the first measurement circuit or the first battery cell fluctuates, it will not exceed the difference of U1, thereby improving the accuracy of fault identification of the first battery cell.

[0016] A second aspect of this application provides a fuel cell testing device, including a testing circuit as described in the first aspect of this application and any example thereof.

[0017] In this application, the beneficial effects of the second aspect of the embodiments can be referred to the first aspect of the embodiments and any example thereof.

[0018] In some examples of the second aspect of the embodiments of this application, the fuel cell testing device further includes: a third testing interface for connecting to the negative electrode of a second battery cell, wherein the second battery cell is a battery cell stacked in a fuel cell stack; a fourth testing interface for connecting to the positive electrode of the second battery cell; a fourth module connected between the third testing interface and a testing reference terminal, wherein the equivalent resistance of the fourth module is greater than or equal to the equivalent resistance of the first module; and a third measuring circuit for measuring the voltage between the third testing interface and the fourth testing interface, wherein the third measuring circuit is connected between the third testing interface and the fourth testing interface.

[0019] In this embodiment, the voltage of the second battery cell can be measured by the third measurement circuit. When the equivalent resistance of the fourth module is greater than the equivalent resistance of the first module, the current flowing through the fourth module can be reduced, thereby reducing the energy consumption of the fuel cell detection device.

[0020] In some examples of the second aspect of the embodiments of this application, the fuel cell testing device further includes: a fifth testing interface for connecting the positive electrode of a third battery cell, wherein the third battery cell is stacked adjacent to the second battery cell, and the negative electrode of the third battery cell is connected to the positive electrode of the second battery cell at the same voltage; a fifth module connected between the third testing interface and the fifth testing interface, wherein the equivalent resistance of the fifth module is greater than or equal to the equivalent resistance of the first module; and a fourth measuring circuit for measuring the voltage between the third testing interface and the fifth testing interface, wherein the fourth measuring circuit is connected between the third testing interface and the fifth testing interface.

[0021] In this embodiment, when the connection between the third detection interface and the positive electrode of the second battery cell is disconnected, the measurement result of the third measurement circuit changes accordingly, and the measurement result of the fourth measurement circuit changes accordingly. Based on the measurement results of the third measurement circuit and the fourth measurement circuit, this fault can be determined so that corresponding handling measures can be taken according to the fault type.

[0022] In some examples of the second aspect of the embodiments of this application, the fuel cell testing device further includes: a sixth testing interface for connecting the negative electrode of a fourth battery cell, wherein the fourth battery cell is stacked adjacent to the second battery cell, and the positive electrode of the fourth battery cell is connected to the negative electrode of the second battery cell at the same voltage; a sixth module connected between the fourth testing interface and the sixth testing interface, wherein the equivalent resistance of the sixth module is greater than or equal to the equivalent resistance of the first module; and a fifth measuring circuit for measuring the voltage between the fourth testing interface and the sixth testing interface, wherein the fifth measuring circuit is connected between the fourth testing interface and the sixth testing interface.

[0023] In this embodiment, when the connection between the fourth detection interface and the negative electrode of the second battery cell is disconnected, the measurement results of the third measurement circuit change accordingly, and the measurement results of the fifth measurement circuit change accordingly. Based on the measurement results of the third measurement circuit and the fifth measurement circuit, this fault can be determined so that corresponding handling measures can be taken according to the fault type.

[0024] In some examples of the second aspect of the embodiments of this application, the fuel cell testing device includes a measurement circuit board, on which a detection reference terminal, a first module, a first measurement circuit, a fourth module and a third measurement circuit are integrated, and a second detection interface and a fourth detection interface are integrated. The first battery cell and the second battery cell are stacked adjacent to each other, and the positive electrode of the first battery cell and the negative electrode of the second battery cell are connected at the same voltage.

[0025] In this embodiment, when the connection between the second detection interface and the positive electrode of the first battery cell is disconnected, the measurement result of the third measurement circuit changes accordingly, and the measurement result of the first measurement circuit may also change accordingly. Based on the measurement results of the first and third measurement circuits, the fault can be determined. Compared with fault judgment based solely on the measurement results of the first measurement circuit, redundant judgment can be provided for fault diagnosis, thereby improving the reliability of fault diagnosis.

[0026] A third aspect of the embodiments of this application provides a fuel cell system, including: a stack, the stack including a first cell, the negative electrode of the first cell being connected to the ground terminal of the stack; and a fuel cell testing device as described in the second aspect of the embodiments of this application and any example thereof, wherein a first testing interface of the fuel cell testing device is electrically connected to the negative electrode of the first cell, and a second testing interface of the fuel cell testing device is electrically connected to the positive electrode of the first cell.

[0027] In the embodiments of this application, the beneficial effects of the third aspect of the embodiments of this application can be referred to the first aspect of the embodiments of this application and any example thereof, as well as the second aspect of the embodiments of this application and any example thereof.

[0028] A fourth aspect of this application provides a detection circuit for detecting a first battery pack in a battery stack. The first battery pack is formed by connecting at least two battery cells in series. The detection circuit includes: a first detection interface for connecting to the negative terminal of the first battery pack; a second detection interface for connecting to the positive terminal of the first battery pack; a detection reference terminal for providing a zero-point reference point for the detection circuit; a first module connected between the second detection interface and the detection reference terminal, the first module having an equivalent resistance greater than or equal to 100kΩ; a second module connected between the first detection interface and the detection reference terminal, the second module having an equivalent resistance greater than or equal to 100kΩ; and a first measurement circuit for measuring the voltage between the first detection interface and the second detection interface, the first measurement circuit being connected between the second detection interface and the first detection interface.

[0029] In some examples of the fourth aspect of the embodiments of this application, the detection circuit further includes: a voltage module, which is used to output a voltage signal, the positive output terminal of the voltage module is connected to the first detection interface, the negative output terminal of the voltage module is connected to the detection reference terminal, and the output voltage of the voltage module is greater than twice the output voltage of the first battery pack.

[0030] In some examples of the fourth aspect of the embodiments of this application, the detection circuit further includes: the second module includes a second measurement circuit, the second measurement circuit is connected between the first detection interface and the detection reference terminal, and the second measurement circuit is used to measure the output voltage of the voltage module.

[0031] In some examples of the fourth aspect of the embodiments of this application, the detection circuit further includes: the detection circuit further includes a unidirectional diode, the negative terminal of the unidirectional diode is connected to the detection reference terminal; the output negative terminal of the voltage module is connected to the detection reference terminal, including that the output negative terminal of the voltage module is connected to the positive terminal of the unidirectional diode; the second module is connected between the first detection interface and the detection reference terminal, including that the second module is connected to the positive terminal of the unidirectional diode.

[0032] In some examples of the fourth aspect of the embodiments of this application, the detection circuit further includes: the detection circuit further includes a third module, one end of the third module is connected to the second detection interface through a switch module, the other end of the third module is connected to the first detection interface, the equivalent resistance of the third module is less than or equal to 1kΩ, and when the switch module is in a closed state, the third module is connected in series with the first battery cell.

[0033] In some examples of the fourth aspect of the embodiments of this application, the detection circuit further includes: the output voltage of the voltage module is greater than four times the output voltage of the first battery pack. Attached Figure Description

[0034] Figure 1This is a connection diagram of a fuel cell system based on existing technology.

[0035] Figure 2 This is a schematic diagram showing the connection between a single-unit detection circuit and a fuel cell stack, which is one example of an embodiment of this application.

[0036] Figure 3 This is a schematic diagram showing the connection between the individual detection circuit and the fuel cell stack, which is an example of a second embodiment of this application.

[0037] Figure 4 This is a schematic diagram showing the connection between the individual detection circuit and the fuel cell stack, which is an example of the third embodiment of this application.

[0038] Figure 5 This is a schematic diagram showing the connection between the individual detection circuit and the fuel cell stack, which is an example of the fourth embodiment of this application.

[0039] Figure 6 This is a schematic diagram illustrating the connection between a fuel cell testing device and a fuel cell stack, which is one example of an embodiment of this application.

[0040] Figure label:

[0041] 100. Battery stack; 101. Voltage measurement circuit; 110. First battery cell; 120. Second battery cell under test; 130. Third battery cell under test; 140. Fourth battery cell under test; 210. First resistor; 220. Second resistor; 230. Third resistor; 240. Fourth resistor; 310. Grounding resistor; 410. First grounding point; 420. Second grounding point; 510. First measurement circuit; 511. First detection interface; 512. Second detection interface; 520. Second measurement circuit; 530. Third voltage measurement circuit; 531. Third device interface; 540. Fourth voltage measurement circuit; 541. Fourth device interface; 550. Fifth voltage measurement circuit; 551. Fifth device interface; 600. Reference voltage source; 710. Unidirectional diode; 720. Reference resistor; 730. Switching module. Detailed Implementation

[0042] The terms “first,” “second,” “third,” “fourth,” etc. (if present) in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a particular order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of this application described herein can be implemented, for example, in orders other than those illustrated or described herein. Furthermore, the terms “comprising” and “corresponding to,” and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0043] The technical solutions of the embodiments of this application are described below with reference to the accompanying drawings. The technical solutions of the embodiments of this application can be combined in any way, in whole or in part, without departing from the spirit of the invention. These combinations of all or part of the technical solutions should be understood as equivalent technical solutions of the embodiments of this application and are described in the embodiments of the application.

[0044] The battery stack in this application embodiment is composed of multiple battery cells stacked together. The number of battery cells shown in the illustrations or examples does not constitute a limitation on the number of battery cells in the battery stack. It is understood that the number of battery cells in the battery stack can be dozens or hundreds.

[0045] This application provides a single-cell detection circuit for detecting a grounded first battery cell in a battery stack. The single-cell detection circuit includes: a first detection interface for connecting to the negative terminal of the first battery cell; a second detection interface for connecting to the positive terminal of the first battery cell; a detection reference terminal for providing a zero-point reference for the single-cell detection circuit; a first module connected between the second detection interface and the detection reference terminal, the equivalent resistance of the first module being greater than or equal to 100kΩ; a second module connected between the first detection interface and the detection reference terminal, the equivalent resistance of the second module being greater than or equal to 100kΩ; a voltage module for outputting a voltage signal, the positive output terminal of the voltage module being connected to the first detection interface, the negative output terminal of the voltage module being connected to the detection reference terminal, and the output voltage of the voltage module being greater than twice the output voltage of the first battery cell; and a first measurement circuit for measuring the voltage between the first detection interface and the second detection interface, the first measurement circuit being connected between the second detection interface and the first detection interface.

[0046] Specifically, such as Figure 2As shown, the fuel cell stack 100 includes a first battery cell 110, wherein the first battery cell 110 is disposed at the negative terminal of the fuel cell stack 100, and the negative terminal of the first battery cell 110 can also be the negative terminal of the fuel cell stack 100. The negative terminal of the first battery cell 110 is connected to a second grounding point 420, which is used to provide a zero-point reference point to the fuel cell stack 100.

[0047] The individual unit detection circuit includes a first resistor 210, a grounding resistor 310, a first grounding point 410, a first measurement circuit 510, a first detection interface 511, a second detection interface 512, and a reference voltage source 600. For ease of explanation, in this embodiment, the first resistor 210 can be equivalent to the first module described above, the grounding resistor 310 can be equivalent to the second module described above, the first grounding point 410 can be equivalent to the detection reference terminal described above, the reference voltage source 600 can be equivalent to the voltage module described above, and the second grounding point 420 can be equivalent to the reference ground of the fuel cell stack described above.

[0048] The first detection interface 511 is connected to the negative terminal of the first battery cell 110 via the first connecting line. When the connection of the first connecting line is normal, the first detection interface 511 is connected to the second grounding point 420. The second detection interface 512 is connected to the positive terminal of the first battery cell 110 via the second connecting line.

[0049] The resistance of the first resistor 210 is greater than or equal to 100kΩ. Preferably, the resistance of the first resistor 210 is greater than or equal to 1MΩ. One end of the first resistor 210 is connected to the second detection interface 512, and the other end of the first resistor 210 is connected to the first grounding point 410.

[0050] The grounding resistor 310 has a resistance value greater than or equal to 100kΩ. The grounding resistor 310 can be a pure resistor, a capacitor, or other electronic components with equivalent impedance. One end of the grounding resistor 310 is connected to the first detection interface 511, and the other end of the grounding resistor 310 is connected to the first grounding point 410.

[0051] The first measurement circuit 510 can be a voltage measurement circuit, or it can include a voltage measurement circuit, or it can be an electronic component with voltage measurement function, or it can be a circuit part with voltage measurement function integrated in other electronic components. The first measurement circuit 510 is connected between the first detection interface 511 and the second detection interface 512. Preferably, the positive measurement terminal of the first measurement circuit 510 is connected to the second detection interface 512, and the negative measurement terminal of the first measurement circuit 510 is connected to the first detection interface 511.

[0052] The reference voltage source 600 can output a reference voltage signal. The positive output terminal of the reference voltage source 600 is connected to the first detection interface 511, and the negative output terminal of the reference voltage source 600 is connected to the first ground point 410.

[0053] For example, hydrogen and oxygen are introduced into the fuel cell stack 100. The hydrogen and oxygen react chemically in the fuel cell stack 100 to produce water. Each battery cell in the fuel cell stack 100 generates a voltage. For example, the rated voltage of the first battery cell 110 is 0.5V. When the first battery cell 110 is in normal operating condition, the output voltage of the first battery cell 110 is 0.5V (or near 0.5V). The first measuring circuit 510 measures the voltage between the first detection interface 511 and the second detection interface 512, and can obtain a measurement result of 0.5V. For another example, the output voltage of the reference voltage source 600 is 1.2V. In some cases, the water generated in the fuel cell stack 100 is not drained in time, thus affecting the water level in the fuel cell stack 100. Water accumulation in the first battery cell 110 affects its normal output. In this case, the voltage across the first battery cell 110 varies between 0V and -0.5V. The first measurement circuit 510 measures the voltage between the first detection interface 511 and the second detection interface 512, obtaining a measurement result of -0.3V. Based on this measurement result, it can be determined that water accumulation has occurred in the first battery cell 110. In some cases, the connection of the first connecting line is faulty, and the connection between the first detection interface 511 and the negative terminal of the first battery cell 110 is broken. In this case, the positive measurement terminal of the first measurement circuit 510 is connected to the positive terminal of the first battery cell 110. The positive measuring terminal of circuit 510 has a potential equivalent to +0.5V at the second grounding point 420. The negative measuring terminal of the first measuring circuit 510 is connected to the positive output of the reference voltage source 600, and its potential is equivalent to +1.2V at the first grounding point 410. If the potentials of the first grounding point 410 and the second grounding point 420 are the same, similar, or substantially the same, the first measuring circuit 510 measures the voltage between the first detection interface 511 and the second detection interface 512. For example, a measurement result of -0.7V can be obtained. Based on this measurement result, it can be determined that there is a problem with the connection of the first connecting line, such as a broken wire or a disconnection between the first connecting line and the first detection interface 511. Alternatively, the first connecting line may be disconnected from the first battery cell 110; in some cases, the connection of the second connecting line may be faulty, and the connection between the second detection interface 512 and the positive terminal of the first battery cell 110 may be disconnected. In this case, the first measuring circuit 510, the first resistor 210, and the reference voltage source 600 form a measuring loop. The equivalent resistance of the first measuring circuit 510 is much greater than the equivalent resistance of the first resistor 210. The positive measuring terminal of the first measuring circuit 510 is approximately equivalent to the potential of the negative output terminal of the reference voltage source 600, and the negative measuring terminal of the first measuring circuit 510 is equivalent to the potential of the positive output terminal of the reference voltage source 600. The first measuring circuit 510 performs a measurement, for example, and can obtain -1.The 2V measurement result indicates a problem with the second connection line, such as a broken wire, a disconnection between the second connection line and the second detection interface 512, or a disconnection between the second connection line and the first battery cell 110.

[0054] In some examples of embodiments of this application, the second module includes a second measurement circuit connected between the first detection interface and the detection reference terminal. The second measurement circuit is used to measure the output voltage of the voltage module. This example can be combined with other examples of embodiments of this application.

[0055] Specifically, such as Figure 3 As shown, the fuel cell stack 100 includes a first battery cell 110, the negative terminal of which is connected to a second grounding point 420. The second grounding point 420 is used to provide a zero-point reference point to the fuel cell stack 100. The cell detection circuit includes a first resistor 210, a first grounding point 410, a first measurement circuit 510, a second measurement circuit 520, a first detection interface 511, a second detection interface 512, and a reference voltage source 600. For ease of explanation, the first resistor 210 in this embodiment can be equivalent to the first module mentioned above in this embodiment, and the second measurement circuit 520 in this embodiment can be equivalent to the second module mentioned above in this embodiment. In some examples, the second measurement circuit 520 can be connected in series or in parallel with the grounding resistor 310. In this case, the combination of the second measurement circuit 520 and the grounding resistor 310 is equivalent to the second module. The first grounding point 410 in this embodiment can be equivalent to the detection reference terminal mentioned above in this embodiment, the reference voltage source 600 in this embodiment can be equivalent to the voltage module mentioned above in this embodiment, and the second grounding point 420 in this embodiment is equivalent to the reference ground of the fuel cell stack mentioned above in this embodiment.

[0056] The first detection interface 511 is connected to the negative terminal of the first battery cell 110 via a first connecting line, and the second detection interface 512 is connected to the positive terminal of the first battery cell 110 via a second connecting line; the resistance of the first resistor 210 is greater than or equal to 100kΩ, preferably greater than or equal to 1MΩ, one end of the first resistor 210 is connected to the second detection interface 512, and the other end of the first resistor 210 is connected to the first grounding point 410; the first measurement circuit 510 is connected between the first detection interface 511 and the second detection interface 512, preferably, the positive measurement terminal of the first measurement circuit 510 is connected to the second detection interface 512, and the negative measurement terminal of the first measurement circuit 510 is connected to the first detection interface 511; the positive output terminal of the reference voltage source 600 is connected to the first detection interface 511, and the negative output terminal of the reference voltage source 600 is connected to the first grounding point 410.

[0057] The equivalent resistance of the second measuring circuit 520 is greater than or equal to 100kΩ, preferably greater than or equal to 10MΩ. The second measuring circuit 520 can be a voltage measuring circuit, or may include a voltage measuring circuit, or may be an electronic component with voltage measuring function, or a circuit section with voltage measuring function integrated into other electronic components. The second measuring circuit 520 is connected between the first detection interface 511 and the first ground point 410. Preferably, the positive measuring terminal of the second measuring circuit 520 is connected to the first detection interface 511, and the negative measuring terminal of the second measuring circuit 520 is connected to the first ground point 410. It is understood that in some cases, the first measuring circuit 510 and the second measuring circuit 520 can use the same or similar hardware configuration.

[0058] For example, the output voltage of the reference voltage source 600 can be measured based on the measurement results of the second measurement circuit 520. When the output voltage of the reference voltage source 600 fluctuates, the measurement results of the first measurement circuit 510 can be corrected based on the measurement results of the second measurement circuit 520, thereby reducing the impact caused by the fluctuation of the reference voltage source 600 and improving the accuracy of fault diagnosis of the first battery cell 110 and its connections.

[0059] In some examples of embodiments of this application, the single-unit detection circuit further includes a unidirectional diode, the negative terminal of which is connected to a detection reference terminal; the negative output terminal of the aforementioned voltage module is connected to the detection reference terminal, including connecting the negative output terminal of the voltage module to the positive terminal of the unidirectional diode; the aforementioned second module is connected between the first detection interface and the detection reference terminal, including connecting the second module to the positive terminal of the unidirectional diode. This example can be combined with other examples of embodiments of this application.

[0060] Specifically, such as Figure 4As shown, the fuel cell stack 100 includes a first battery cell 110, the negative terminal of which is connected to a second grounding point 420. The second grounding point 420 provides a zero-point reference point to the fuel cell stack 100. The cell detection circuit includes a first resistor 210, a first grounding point 410, a first measurement circuit 510, a second measurement circuit 520, a first detection interface 511, a second detection interface 512, a reference voltage source 600, and a unidirectional diode 710. For ease of explanation, the first resistor 210 in this embodiment can be equivalent to the first module described above, the second measurement circuit 520 can be equivalent to the second module described above, the first grounding point 410 can be equivalent to the detection reference terminal described above, the reference voltage source 600 can be equivalent to the voltage module described above, and the second grounding point 420 can be equivalent to the reference ground of the fuel cell stack described above.

[0061] The first detection interface 511 is connected to the negative terminal of the first battery cell 110 via a first connecting line, and the second detection interface 512 is connected to the positive terminal of the first battery cell 110 via a second connecting line; the resistance of the first resistor 210 is greater than or equal to 100kΩ, preferably greater than or equal to 1MΩ, one end of the first resistor 210 is connected to the second detection interface 512, and the other end of the first resistor 210 is connected to the first grounding point 410; the positive measuring terminal of the first measuring circuit 510 is connected to the second detection interface 512, and the negative measuring terminal of the first measuring circuit 510 is connected to the first detection interface 511.

[0062] The positive measuring terminal of the second measuring circuit 520 is connected to the first detection interface 511, the negative measuring terminal of the second measuring circuit 520 is connected to the positive terminal of the unidirectional diode 710, the positive output terminal of the reference voltage source 600 is connected to the first detection interface 511, the negative output terminal of the reference voltage source 600 is connected to the positive terminal of the unidirectional diode 710, and the negative terminal of the unidirectional diode 710 is connected to the first grounding point 410; preferably, the dead zone voltage of the unidirectional diode 710 is higher than or equal to the rated voltage of the first battery cell 110.

[0063] For example, the unidirectional diode 710 can prevent the first battery cell 110, the first resistor 210, and the reference voltage source 600 from forming a current loop. In addition, when a problem occurs in the connection of the first connecting line, the connection between the first ground point 410 and the second ground point 420 is broken. If the potential of the first ground point 410 fluctuates relative to the potential of the second ground point 420, the unidirectional diode 710 can prevent the current from reversing, thereby reducing the energy consumption of the cell detection circuit and improving the detection reliability of the cell detection circuit.

[0064] In some examples of embodiments of this application, the single-cell detection circuit further includes a third module. One end of the third module is connected to the second detection interface through a switch module, and the other end of the third module is connected to the first detection interface. The equivalent resistance of the third module is less than or equal to 1kΩ. When the switch module is in a closed-circuit state, the third module is connected in series with the first battery cell.

[0065] Specifically, such as Figure 5 As shown, the fuel cell stack 100 includes a first battery cell 110, the negative terminal of which is connected to a second grounding point 420. The second grounding point 420 provides a zero-point reference point to the fuel cell stack 100. The cell detection circuit includes a first resistor 210, a first grounding point 410, a first measurement circuit 510, a second measurement circuit 520, a first detection interface 511, a second detection interface 512, a reference voltage source 600, a reference resistor 720, and a switching module 730. For ease of explanation, the first resistor 210 in this embodiment can be equivalent to the first module described above in this embodiment, the second measurement circuit 520 in this embodiment can be equivalent to the second module described above in this embodiment, the first grounding point 410 in this embodiment can be equivalent to the detection reference terminal described above in this embodiment, the second grounding point 420 in this embodiment can be equivalent to the reference ground of the fuel cell stack described above in this embodiment, the reference voltage source 600 in this embodiment can be equivalent to the voltage module described above in this embodiment, and the reference resistor 720 in this embodiment can be equivalent to the third module described above in this embodiment.

[0066] The first detection interface 511 is connected to the negative terminal of the first battery cell 110 via a first connecting line, and the second detection interface 512 is connected to the positive terminal of the first battery cell 110 via a second connecting line; the resistance of the first resistor 210 is greater than or equal to 100kΩ, preferably greater than or equal to 1MΩ, one end of the first resistor 210 is connected to the second detection interface 512, and the other end of the first resistor 210 is connected to the first grounding point 410; the positive measuring terminal of the second measuring circuit 520 is connected to the first detection interface 511, and the negative measuring terminal of the second measuring circuit 520 is connected to the first grounding point 410; the positive output terminal of the reference voltage source 600 is connected to the first detection interface 511, and the negative output terminal of the reference voltage source 600 is connected to the first grounding point 410.

[0067] The reference resistor 720 has a resistance value less than or equal to 1kΩ. Preferably, the equivalent resistance value of the reference resistor 720 is greater than or equal to the equivalent resistance value of the first battery cell 110. One end of the reference resistor 720 is connected to the first detection interface 511, and the other end of the reference resistor 720 is connected to one end of the switch module 730. The other end of the switch module 730 is connected to the second detection interface 512. The positive measurement terminal of the first measurement circuit 510 is connected to the second detection interface 512, and the negative measurement terminal of the first measurement circuit 510 is connected to the first detection interface 511. When the switch module 730 is in an open circuit state, the reference resistor 720 is not in the detection loop, and the first measurement circuit 510 can detect the first battery cell 110. The voltage of a single battery cell 110 is measured. When the switch module 730 is in a closed state, the first battery cell 110, the reference resistor 720, and the switch module 730 form a current loop. The reference resistor 720 is connected in parallel with the first measurement circuit 510. The first measurement circuit 510 can measure the voltage across the reference resistor 720. Based on the change in the measurement result of the first measurement circuit 510 when the state of the switch module 730 is switched, the equivalent resistance on the first connection line and the second connection line can be judged. Furthermore, the connection status of the first connection line and the second connection line can be determined based on the equivalent resistance on the first connection line and the second connection line, such as whether there is a loose connection.

[0068] In this embodiment, the output voltage of the voltage module is greater than four times the output voltage of the first battery cell. Specifically, exemplarily, the rated output voltage of the first battery cell 110 is 0.5V, and the rated output voltage of the reference voltage source 600 is greater than 2V. The reference voltage source 600 can be used in the voltage module described above in this embodiment.

[0069] This application also provides a fuel cell testing device, which includes a single-cell testing circuit, which can refer to the foregoing embodiments of this application and any of its examples.

[0070] In this embodiment, the fuel cell testing device further includes: a third testing interface for connecting to the negative electrode of a second battery cell, wherein the second battery cell is a stacked battery cell in a fuel cell stack; a fourth testing interface for connecting to the positive electrode of the second battery cell; a fourth module connected between the fourth testing interface and a testing reference terminal, wherein the equivalent resistance of the fourth module is greater than or equal to the equivalent resistance of the first module; and a third measurement circuit for measuring the voltage between the third testing interface and the fourth testing interface, wherein the third measurement circuit is connected between the third testing interface and the fourth testing interface.

[0071] In this embodiment, the fuel cell testing device further includes: a fifth testing interface for connecting the positive electrode of the third battery cell, wherein the third battery cell is stacked adjacent to the second battery cell, and the negative electrode of the third battery cell is connected to the positive electrode of the second battery cell at the same voltage; a fifth module connected between the third testing interface and the fifth testing interface, wherein the equivalent resistance of the fifth module is greater than or equal to the equivalent resistance of the first module; and a fourth measurement circuit for measuring the voltage between the third testing interface and the fifth testing interface, wherein the fourth measurement circuit is connected between the third testing interface and the fifth testing interface.

[0072] In this embodiment, the fuel cell testing device further includes: a sixth testing interface for connecting the negative electrode of a fourth battery cell, wherein the fourth battery cell is stacked adjacent to the second battery cell, and the positive electrode of the fourth battery cell is connected to the negative electrode of the second battery cell at the same voltage; a sixth module connected between the fourth and sixth testing interfaces, wherein the equivalent resistance of the sixth module is greater than or equal to the equivalent resistance of the first module; and a fifth measurement circuit for measuring the voltage between the fourth and sixth testing interfaces, wherein the fifth measurement circuit is connected between the fourth and sixth testing interfaces.

[0073] In this embodiment of the application, the fuel cell testing device further includes a measurement circuit board, which integrates a detection reference terminal, a first module, a first measurement circuit, a fourth module, and a third measurement circuit. The first battery cell and the second battery cell are stacked adjacent to each other, and the positive electrode of the first battery cell and the negative electrode of the second battery cell are connected at the same voltage. The second detection interface and the fourth detection interface are integrated.

[0074] Specifically, such as Figure 6 As shown, the battery stack 100 includes a first battery cell 110, a second battery cell under test 120, a third battery cell under test 130, and a fourth battery cell under test 140. The negative terminal of the first battery cell 110 is connected to a second grounding point 420, which provides a zero-point reference point to the battery stack 100. The second battery cell under test 120 is stacked adjacent to the first battery cell 110, and its negative terminal is connected to the positive terminal of the first battery cell 110. The third battery cell under test... Battery cell 130 is stacked adjacent to the second battery cell 120 under test. The negative terminal of the third battery cell 130 under test is connected to the positive terminal of the second battery cell 120 under test. The fourth battery cell 140 under test is stacked adjacent to the third battery cell 130 under test. The negative terminal of the fourth battery cell 140 under test is connected to the positive terminal of the third battery cell 130 under test. For example, each battery cell in the stack 100 is identical. For example, the rated voltage of each battery cell in the stack 100 is 0.5V.

[0075] The fuel cell testing device includes a wiring bracket, on which are provided a first testing interface 511, a second testing interface 512, a third device interface 531, a fourth device interface 541, and a fifth device interface 551. The first testing interface 511 is connected to the negative electrode of the first battery cell 110 via a first connecting line. The second testing interface 512 is connected to the positive electrode of the first battery cell 110 via a second connecting line. The third device interface 531 is connected to the negative electrode of the third battery cell 130 under test via a third connecting line. The fourth device interface 541 is connected to the negative electrode of the fourth battery cell 140 under test via a fourth connecting line. The fifth device interface 551 is connected to the positive electrode of the fourth battery cell 140 under test via a fifth connecting line.

[0076] The fuel cell testing device includes a first measuring circuit 510, a second measuring circuit 520, a third voltage measuring circuit 530, a fourth voltage measuring circuit 540, and a fifth voltage measuring circuit 550. The negative measuring terminal of the first measuring circuit 510 is connected to a first detection interface 511, and the positive measuring terminal of the first measuring circuit 510 is connected to a second detection interface 512. The positive measuring terminal of the second measuring circuit 520 is connected to the first detection interface 511, and the negative measuring terminal of the second measuring circuit 520 is connected to the anode of a unidirectional diode 710. The positive measuring terminal of the third voltage measuring circuit 530 is connected to a third device interface 531, and the negative measuring terminal of the third voltage measuring circuit 530 is connected to the second detection interface 512. The positive measuring terminal of the fourth voltage measuring circuit 540 is connected to a fourth device interface 541, and the negative measuring terminal of the fourth voltage measuring circuit 540 is connected to the third device interface 531. The positive measuring terminal of the fifth voltage measuring circuit 550 is connected to the first detection interface 510, and the negative measuring terminal of the fifth voltage measuring circuit 550 is connected to the third device interface 531. The measuring terminal of the fifth voltage measuring circuit 550 is connected to the fifth device interface 551, and the negative measuring terminal of the fifth voltage measuring circuit 550 is connected to the fourth device interface 541. The first measuring circuit 510, the second measuring circuit 520, the third voltage measuring circuit 530, the fourth voltage measuring circuit 540, and the fifth voltage measuring circuit 550 are all integrated on the measuring circuit board. The third voltage measuring circuit 530 can be a voltage measuring circuit, an electronic component with voltage measuring function, or a circuit part with voltage measuring function integrated in other electronic components. The fourth voltage measuring circuit 540 can be a voltage measuring circuit, an electronic component with voltage measuring function, or a circuit part with voltage measuring function integrated in other electronic components. The fifth voltage measuring circuit 550 can be a voltage measuring circuit, an electronic component with voltage measuring function, or a circuit part with voltage measuring function integrated in other electronic components.

[0077] The fuel cell testing device includes a first resistor 210, a second resistor 220, a third resistor 230, and a fourth resistor 240. The first resistor 210 is connected between the second testing interface 512 and the first ground point 410; the second resistor 220 is connected between the third device interface 531 and the first ground point 410; the third resistor 230 is connected between the fourth device interface 541 and the first ground point 410; and the fourth resistor 240 is connected between the fifth device interface 551 and the first ground point 410. All four resistors (210, 220, 230, and 240) can be integrated onto a measurement circuit board. The resistance of the first resistor 210 is greater than or equal to... Preferably, the resistance of the first resistor 210 is greater than or equal to 1MΩ; the resistance of the second resistor 220 is greater than or equal to 100kΩ; preferably, the resistance of the second resistor 220 is greater than or equal to 1MΩ; the resistance of the third resistor 220 is greater than or equal to 100kΩ; preferably, the resistance of the third resistor 220 is greater than or equal to 1MΩ; the resistance of the fourth resistor 240 is greater than or equal to 100kΩ; preferably, the resistance of the fourth resistor 240 is greater than or equal to 1MΩ; the resistance of the second resistor 220 is greater than or equal to the resistance of the first resistor 210, the resistance of the third resistor 220 is greater than or equal to the resistance of the first resistor 210, and the resistance of the fourth resistor 240 is greater than or equal to the resistance of the first resistor 210.

[0078] The positive output of the reference voltage source 600 is connected to the first detection interface 511, the negative output of the reference voltage source 600 is connected to the positive terminal of the unidirectional diode 710, and the negative terminal of the unidirectional diode 710 is connected to the first ground point 410. The reference voltage source 600 and the unidirectional diode 710 can be integrated on the measurement circuit board.

[0079] It is understood that the reference voltage source 600 can be equivalent to the voltage module described in the embodiments of this application.

[0080] In some examples of embodiments of this application, the second battery cell under test 120 can be equivalent to the second battery cell mentioned in the embodiments of this application. Correspondingly, the second detection interface is equivalent to the third detection interface mentioned in the embodiments of this application, the third device interface 531 is equivalent to the fourth detection interface mentioned in the embodiments of this application, the second resistor 220 is equivalent to the fourth module mentioned in the embodiments of this application, and the third voltage measurement circuit 530 is equivalent to the third measurement circuit mentioned in the embodiments of this application. Furthermore, the third battery cell under test 130 can be equivalent to the third battery cell mentioned in the embodiments of this application. Correspondingly, the fourth device interface 541 is equivalent to the fifth detection interface mentioned in the embodiments of this application, the third resistor 230 is equivalent to the fifth module mentioned in the embodiments of this application, and the fourth voltage measurement circuit 540 is equivalent to the fourth measurement circuit mentioned in the embodiments of this application.

[0081] In some examples of embodiments of this application, the third battery cell under test 130 can be equivalent to the second battery cell mentioned in the embodiments of this application. Correspondingly, the third device interface 531 is equivalent to the third detection interface mentioned in the embodiments of this application, the fourth device interface 541 is equivalent to the fourth detection interface mentioned in the embodiments of this application, the third resistor 230 is equivalent to the fourth module mentioned in the embodiments of this application, and the fourth voltage measurement circuit 540 is equivalent to the third measurement circuit mentioned in the embodiments of this application. Further, the fourth battery cell under test 140 can be equivalent to the third battery cell mentioned in the embodiments of this application. Correspondingly, the fifth device interface 551 is equivalent to the fifth detection interface mentioned in the embodiments of this application, the fourth resistor 240 is equivalent to the fifth module mentioned in the embodiments of this application, and the fifth voltage measurement circuit 550 is equivalent to the fourth measurement circuit mentioned in the embodiments of this application. Further, the second battery cell under test 120 can be equivalent to the fourth battery cell mentioned in the embodiments of this application. Correspondingly, the second detection interface 512 is equivalent to the sixth detection interface mentioned in the embodiments of this application, the second resistor 220 is equivalent to the sixth module mentioned in the embodiments of this application, and the third voltage measurement circuit 530 is equivalent to the fifth measurement circuit mentioned in the embodiments of this application.

[0082] In some examples of embodiments of this application, the fourth battery cell under test 140 can be equivalent to the second battery cell mentioned in the embodiments of this application. Correspondingly, the fourth device interface 541 is equivalent to the third detection interface mentioned in the embodiments of this application, the fifth device interface 551 is equivalent to the fourth detection interface mentioned in the embodiments of this application, the fourth resistor 240 is equivalent to the fourth module mentioned in the embodiments of this application, and the fifth voltage measurement circuit 550 is equivalent to the third measurement circuit mentioned in the embodiments of this application. Furthermore, the third battery cell under test 130 can be equivalent to the fourth battery cell mentioned in the embodiments of this application. Correspondingly, the third device interface 531 is equivalent to the sixth detection interface mentioned in the embodiments of this application, the third resistor 230 is equivalent to the sixth module mentioned in the embodiments of this application, and the fourth voltage measurement circuit 540 is equivalent to the fifth measurement circuit mentioned in the embodiments of this application.

[0083] This application also provides a fuel cell system, including: a stack, the stack including a first cell, the negative electrode of the first cell being connected to the ground terminal of the stack; a fuel cell testing device, the first testing interface of the fuel cell testing device being electrically connected to the negative electrode of the first cell, and the second testing interface of the fuel cell testing device being electrically connected to the positive electrode of the first cell. The fuel cell testing device can refer to the fuel cell testing devices in the embodiments and examples of this application.

[0084] The battery cells in the aforementioned technical solutions of this application can also be used to replace all or part of the battery packs. A battery pack can be obtained by connecting at least two battery cells in series. For example, if the voltage of a single battery cell is 0.5V, then a battery pack obtained by connecting two battery cells in series can be equivalent to a battery cell with a voltage of 1.0V. A battery pack obtained by connecting three battery cells in series can be equivalent to a battery cell with a voltage of 1.5V. Based on this, the technical solutions of the battery packs can be understood by referring to the aforementioned technical solutions of battery cells. For example, the first battery cell in the aforementioned embodiments can be equivalently replaced with the first battery pack, the second battery cell can be equivalently replaced with the second battery pack, the third battery cell can be equivalently replaced with the third battery pack, and the fourth battery cell can be equivalently replaced with the fourth battery pack. This application will not repeat the description of this.

[0085] The above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application.

Claims

1. A detection circuit, characterized in that, The detection circuit is used to detect the first grounded battery cell in the fuel cell stack, and includes: The first detection interface is used to connect to the negative electrode of the first battery cell; The second detection interface is used to connect to the positive electrode of the first battery cell; The detection reference terminal is used to provide a zero-point reference point for the detection circuit. The first module is connected between the second detection interface and the detection reference terminal, and the equivalent resistance of the first module is greater than or equal to 100kΩ. The second module is connected between the first detection interface and the detection reference terminal, and the equivalent resistance of the second module is greater than or equal to 100kΩ. A voltage module is provided, wherein the voltage module is used to output a voltage signal, the positive terminal of the voltage module is connected to the first detection interface, the negative terminal of the voltage module is connected to the detection reference terminal, and the output voltage of the voltage module is greater than twice the output voltage of the first battery cell. A first measuring circuit is used to measure the voltage between the first detection interface and the second detection interface, and the first measuring circuit is connected between the second detection interface and the first detection interface.

2. The detection circuit according to claim 1, characterized in that, The second module includes a second measurement circuit, which is connected between the first detection interface and the detection reference terminal. The second measurement circuit is used to measure the output voltage of the voltage module.

3. The detection circuit according to claim 1, characterized in that, It also includes a unidirectional diode, the negative terminal of which is connected to the detection reference terminal; the negative output terminal of the voltage module is connected to the detection reference terminal, including the negative output terminal of the voltage module being connected to the positive terminal of the unidirectional diode; the second module is connected between the first detection interface and the detection reference terminal, including the second module being connected to the positive terminal of the unidirectional diode.

4. The detection circuit according to claim 1, characterized in that, It also includes a third module, one end of which is connected to the second detection interface via a switch module, and the other end of which is connected to the first detection interface. The equivalent resistance of the third module is less than or equal to 1kΩ. When the switch module is in a closed-circuit state, the third module is connected in series with the first battery cell.

5. The detection circuit according to claim 1, characterized in that, The output voltage of the voltage module is more than four times the output voltage of the first battery cell.

6. A fuel cell testing device, characterized in that, include: The detection circuit as described in any one of claims 1 to 5; The third detection interface is used to connect to the negative electrode of the second battery cell, which is a battery cell stacked in the stack. The fourth detection interface is used to connect to the positive electrode of the second battery cell; The fourth module is connected between the fourth detection interface and the detection reference terminal, and the equivalent resistance of the fourth module is greater than or equal to the equivalent resistance of the first module. A third measurement circuit is used to measure the voltage between the third detection interface and the fourth detection interface, and the third measurement circuit is connected between the third detection interface and the fourth detection interface.

7. The fuel cell testing device according to claim 6, characterized in that, Also includes: A measurement circuit board is provided, which integrates a detection reference terminal, a first module, a first measurement circuit, a fourth module, and a third measurement circuit. The first battery cell and the second battery cell are stacked adjacent to each other, and the positive terminal of the first battery cell and the negative terminal of the second battery cell are connected at the same voltage. The second detection interface and the fourth detection interface are integrated. A fifth detection interface is used to connect to the positive terminal of a third battery cell, which is stacked adjacent to the second battery cell, and the negative terminal of the third battery cell is connected to the positive terminal of the second battery cell at the same voltage. A fifth module is connected between the third and fifth detection interfaces, and the equivalent resistance of the fifth module is greater than or equal to the equivalent resistance of the first module. A fourth measurement circuit is used to measure the voltage between the third and fifth detection interfaces, and the fourth measurement circuit is connected between the third and fifth detection interfaces. Alternatively, A sixth detection interface is used to connect to the negative terminal of the fourth battery cell, which is stacked adjacent to the second battery cell, and the positive terminal of the fourth battery cell is connected to the negative terminal of the second battery cell at the same voltage. A sixth module is connected between the fourth and sixth detection interfaces, and the equivalent resistance of the sixth module is greater than or equal to the equivalent resistance of the first module. A fifth measurement circuit is used to measure the voltage between the fourth and sixth detection interfaces, and the fifth measurement circuit is connected between the fourth and sixth detection interfaces.

8. A fuel cell system, characterized in that, include: A battery stack, the battery stack including a first battery cell, the negative terminal of the first battery cell being connected to the ground terminal of the battery stack; The fuel cell testing device as described in claim 6 or 7, wherein the first testing interface of the fuel cell testing device is electrically connected to the negative electrode of the first battery cell, and the second testing interface of the fuel cell testing device is electrically connected to the positive electrode of the first battery cell.

9. A detection circuit, characterized in that, For detecting the first battery pack in the fuel cell stack, the first battery pack is formed by at least two battery cells connected in series, the detection circuit includes: The first detection interface is used to connect to the negative terminal of the first battery pack. The second detection interface is used to connect to the positive terminal of the first battery pack. The detection reference terminal is used to provide a zero-point reference point for the detection circuit. The first module is connected between the second detection interface and the detection reference terminal, and the equivalent resistance of the first module is greater than or equal to 100kΩ. The second module is connected between the first detection interface and the detection reference terminal, and the equivalent resistance of the second module is greater than or equal to 100kΩ. A first measuring circuit is used to measure the voltage between the first detection interface and the second detection interface, and the first measuring circuit is connected between the second detection interface and the first detection interface.

10. The detection circuit according to claim 9, characterized in that, Also includes A voltage module is provided, wherein the voltage module is used to output a voltage signal, the positive terminal of the voltage module is connected to the first detection interface, the negative terminal of the voltage module is connected to the detection reference terminal, and the output voltage of the voltage module is greater than twice the output voltage of the first battery pack. The second module includes a second measurement circuit, which is connected between the first detection interface and the detection reference terminal. The second measurement circuit is used to measure the output voltage of the voltage module. The detection circuit further includes a unidirectional diode, the negative terminal of which is connected to the detection reference terminal; the negative output terminal of the voltage module is connected to the detection reference terminal, including the negative output terminal of the voltage module being connected to the positive terminal of the unidirectional diode; the second module is connected between the first detection interface and the detection reference terminal, including the second module being connected to the positive terminal of the unidirectional diode; The detection circuit further includes a third module. One end of the third module is connected to the second detection interface through a switch module, and the other end of the third module is connected to the first detection interface. The equivalent resistance of the third module is less than or equal to 1kΩ. When the switch module is in a closed-circuit state, the third module is connected in series with the battery cell in the first battery pack. The output voltage of the voltage module is more than four times the output voltage of the first battery pack.

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