Fuel cell stack monolithic voltage inspection module and system

Abstract

The invention provides a fuel cell stack monolithic voltage inspection module and a fuel cell stack monolithic voltage inspection system. A stack monolithic voltage connector, a monolithic voltage detection circuit, an auxiliary power supply circuit and a communication circuit are arranged in the inspection module to realize voltage detection of a stack monolithic cell; the low-voltage auxiliary power supply is provided for the inspection module through the electric pile, so that external auxiliary power supply is avoided, and the system is simplified; and the detection loop and the power supply loop are respectively connected with the galvanic pile single cell by adopting a detection line and a power line which are not shared, so that the influence of auxiliary power supply current on detection is avoided, and the detection accuracy and precision are improved.

Description

Technical Field

[0001] The present invention relates to the field of fuel cell voltage detection, and particularly to a single-cell voltage inspection module and system for a fuel cell stack. Background Art

[0002] Fuel cells are characterized by high efficiency and cleanliness. The stack is the part where the fuel cell undergoes an electrochemical reaction. Hydrogen is introduced into the anode of the stack, and air or oxygen is introduced into the cathode of the stack. Under the action of a catalyst, hydrogen reacts with oxygen to generate electricity and water. In order to increase the output voltage and power of the stack, the stack is usually composed of multiple single cells stacked together. A high-power stack can contain up to hundreds of single cells. Under normal operating conditions, the voltage of each single cell should be basically the same. If one or more single cells experience performance degradation or damage, their voltage may decrease. If it reaches zero volts or even negative voltage for a long time without timely protection, it will cause the fault to spread, resulting in damage to the entire stack and even dangerous situations such as fire. Therefore, in order to monitor the single-cell voltage, voltage inspection is usually used. The single-cell voltages in the stack are connected to a voltage detection circuit in various ways for voltage sampling and sent to a control module.

[0003] Patent CN114355195A discloses a fuel cell voltage inspection system, including a main control module and several slave control modules: a low-voltage power supply module is electrically connected to the main control module and each slave control module; the main control module includes a main control chip, a main CAN communication chip, a main isolated CAN communication chip, a main isolated SPI communication chip, a main voltage acquisition chip, a main optical relay, a main low-voltage power supply module, and a main isolated power supply chip. This invention uses a modular approach. Each module obtains power supply from the outside and is equipped with a low-voltage power supply module. Since the measured parts of each module are in different parts of the series-connected stack, their reference potentials are different. Therefore, each low-voltage power supply module needs to be isolated from each other, and an isolation converter is required to obtain an auxiliary power supply, which increases the complexity and cost of the circuit.

[0004] Patent CN115877250A provides a voltage inspection control system, wherein: the input end of the auxiliary DC / DC module is connected to the input end of the filter circuit, and the connection point serves as the input end of the voltage inspection control system and is connected to the fuel cell stack; the auxiliary DC / DC module powers the MCU, the wireless communication module, and the A / D conversion circuit; the output end of the filter circuit is connected to the input end of the A / D conversion circuit; the output end of the A / D conversion circuit is connected to the input end of the MCU; the output end of the MCU is connected to the wireless communication module; the wireless communication module is used to realize the communication between the voltage inspection control system and the external controller; this voltage inspection control system can cancel the low-voltage power supply wire cable and the CAN bus cable set by the existing voltage inspection controller, which can effectively reduce the complexity of the hydrogen fuel system, reduce the failure probability of the low-voltage electrical system, and improve the reliability of the system; at the same time, it is also beneficial to the flexible expansion of fuel cell stacks with different powers. This patent uses the fuel cell stack to power the inspection module, avoiding the isolated low-voltage power supply additionally used in Patent CN114355195A. However, the connection between the single cell of the fuel cell stack and the detection circuit board passes through parts such as the fuel cell stack terminal, the cable, and the circuit board terminal. In particular, the connection between the fuel cell stack and the cable is usually an unreliable part, and the situation of poor contact resulting in a large resistance often occurs; at the same time, in order to sample voltages that may be as many as hundreds of groups, the wire diameter of each cable connecting the single cell and the inspection circuit is thin and the effective conductive area is small, so the cable also has a certain resistance. Both theory and practice show that for obtaining only a current as low as microamps from the fuel cell stack for voltage detection, the influence of the above resistance can be ignored; but if the low-voltage auxiliary power supply and the detection line share a path, because the power supply may need to draw a current of milliamps or even more from the fuel cell stack, the influence of the above resistance may reach millivolts, and even reach the level of hundreds of millivolts when there is poor contact, which will seriously affect the measurement accuracy and cause false protection or other failures. Summary of the Invention

[0005] In view of the above-mentioned disadvantages of the prior art, the purpose of the present invention is to provide a single cell voltage inspection module and system for a fuel cell stack to solve the above prior art problems.

[0006] To achieve the above and other related objectives, the present invention provides a single-cell voltage inspection module for a fuel cell stack to detect the voltage of single cells in the stack, including: a single-cell voltage connector for the fuel cell stack, a single-cell voltage detection circuit, an auxiliary power supply circuit, and a communication circuit; wherein, the single-cell voltage connector for the fuel cell stack is used to connect multiple single cells in the stack through detection lines respectively; the single-cell voltage detection circuit is connected to the single-cell voltage connector for the fuel cell stack and is used to detect the voltage of each connected single cell in the stack through multiple detection channels to obtain corresponding voltage detection data; the auxiliary power supply circuit is connected to the single-cell voltage detection circuit and the communication circuit, and is provided with a power connector, which is used to connect specific single cells in the stack through power lines by the power connector to supply power to the circuits in the inspection module; the communication circuit is connected to the single-cell voltage detection circuit and is used to transmit the voltage detection data of each single cell in the stack to the outside.

[0007] In an embodiment of the present invention, the single-cell voltage detection circuit has multiple detection channels, and each detection channel is an analog-to-digital conversion channel, which is used to convert each voltage signal input to the corresponding channel into a digital signal to obtain corresponding voltage detection data.

[0008] In an embodiment of the present invention, the single-cell voltage connector for the fuel cell stack includes: single-cell voltage connection terminals provided in one-to-one correspondence with each detection channel; each single-cell voltage connection terminal is used to connect one or more single cells in the stack, so that the voltage signal of the connected single cells in the stack can be input to the corresponding detection channel for voltage detection.

[0009] In an embodiment of the present invention, the power connector is provided with two power terminals, including: a positive power terminal, which is used to connect the cathode of the single cell with the highest potential among all the single cells in the stack connected by the single-cell voltage connector for the fuel cell stack through a power line; a negative power terminal, which is used to connect the anode of the single cell with the lowest potential among all the single cells in the stack connected by the single-cell voltage connector for the fuel cell stack through a power line.

[0010] In an embodiment of the present invention, at least two connection parts are provided on the cell bipolar plate of each single cell in the stack; wherein, the types of the connection parts include: a voltage detection connection part and a power connection part; and among them, the voltage detection connection part is used to connect with the single-cell voltage connection terminal of the single-cell voltage connector for the fuel cell stack through a detection line; the power connection part is used to connect with the power terminal of the power connector through a power line.

[0011] In an embodiment of the present invention, the auxiliary power supply circuit further includes: a power conversion device, configured to convert the voltage between the positive power terminal and the negative power terminal of the power connector into a normal operating range when the voltage is not within the normal operating range, so as to supply power to the circuits in the inspection module after conversion.

[0012] To achieve the above and other related objectives, the present invention provides a fuel cell stack single cell voltage inspection system, the system includes: a plurality of single cell batteries stacked on the fuel cell stack, one or more of the fuel cell stack single cell voltage inspection modules, and a controller; wherein, the number of the fuel cell stack single cell voltage inspection modules provided corresponds to the number of the single cell batteries to be measured; at least one voltage detection connection part and at least one power connection part are provided on the bipolar plate of each single cell battery; each fuel cell stack single cell voltage inspection module powered by the fuel cell stack performs voltage detection on the connected single cell batteries, and sends the obtained voltage detection data of each single cell battery to the controller.

[0013] In an embodiment of the present invention, when there are multiple fuel cell stack single cell voltage inspection modules provided, each single cell battery is divided into single cell battery groups that are the same in number as and arranged continuously with the number of the fuel cell stack single cell voltage inspection modules according to the stacking order, and each single cell battery group corresponds to a fuel cell stack single cell voltage inspection module; wherein, each fuel cell stack single cell voltage inspection module is connected to all the single cell batteries in the corresponding single cell battery group, and is also connected to the single cell batteries adjacent to the single cell battery group.

[0014] In an embodiment of the present invention, the single cell voltage connector and the power connector of each fuel cell stack single cell voltage inspection module are respectively connected to the voltage detection connection part and the power connection part of the single cell batteries adjacent to the corresponding single cell battery group through detection lines and power lines.

[0015] In an embodiment of the present invention, the single cell voltage connector and the power connector of each fuel cell stack single cell voltage inspection module are respectively connected to the single cell voltage connector and the power connector of the fuel cell stack single cell voltage inspection module corresponding to the single cell battery group adjacent to the corresponding single cell battery group through detection lines and power lines.

[0016] As described above, the present invention is a single-cell voltage inspection module and system for a fuel cell stack, having the following beneficial effects: The present invention realizes the voltage detection of the single cells of the stack by means of the stack single-cell voltage connector, single-cell voltage detection circuit, auxiliary power supply circuit and communication circuit provided in the inspection module; The present invention provides a low-voltage auxiliary power supply to the inspection module by the auxiliary power supply circuit from the stack, avoiding external auxiliary power supply and simplifying the system; And the detection loop and the power supply loop are respectively connected to the single cells of the stack by non-shared detection lines and power lines, avoiding the influence of the auxiliary power supply current on the detection and improving the detection accuracy and precision. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It shows a schematic structural diagram of the single-cell voltage inspection module of the fuel cell stack in an embodiment of the present invention.

[0018] Figure 2 It shows a schematic structural diagram of the single-cell voltage inspection module of the fuel cell stack in an embodiment of the present invention.

[0019] Figure 3 It shows a schematic diagram of the bipolar plate of the single cell of the stack in an embodiment of the present invention.

[0020] Figure 4 It shows a schematic structural diagram of the single-cell voltage inspection system of the fuel cell stack in an embodiment of the present invention.

[0021] Figure 5 It shows a schematic structural diagram of the single-cell voltage inspection system of the fuel cell stack with multiple voltage inspection modules connected in an embodiment of the present invention.

[0022] Figure 6 It shows a schematic structural diagram of the single-cell voltage inspection system of the fuel cell stack with multiple voltage inspection modules connected in an embodiment of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0023] The following specific examples illustrate the embodiments of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that, without conflict, the following embodiments and the features in the embodiments can be combined with each other.

[0024] It should be noted that in the following description, with reference to the accompanying drawings, several embodiments of the present invention are described. It should be understood that other embodiments may also be used, and mechanical composition, structure, electrical, and operational changes may be made without departing from the spirit and scope of the present invention. The following detailed description should not be considered restrictive, and the scope of the embodiments of the present invention is only defined by the claims of the published patent. The terms used herein are only for describing specific embodiments and are not intended to limit the present invention. Spatially related terms, such as "upper", "lower", "left", "right", "below", "beneath", "lower", "above", "upper", etc., may be used in the text to facilitate the description of the relationship between one element or feature shown in the figure and another element or feature.

[0025] Throughout the specification, when it is said that a certain part is "connected" to another part, this includes not only the case of "direct connection" but also the case of "indirect connection" with other elements placed therebetween. Additionally, when it is said that a certain part "includes" a certain constituent element, unless there is a particularly contrary record, it does not exclude other constituent elements, but rather means that other constituent elements may also be included.

[0026] The first, second, and third, etc. terms mentioned therein are used to describe various parts, components, regions, layers, and / or segments, but are not limited thereto. These terms are only used to distinguish one part, component, region, layer, or segment from other parts, components, regions, layers, or segments. Therefore, the first part, component, region, layer, or segment described below may refer to the second part, component, region, layer, or segment within the scope not exceeding the present invention.

[0027] Furthermore, as used herein, the singular forms "a", "an", and "the" are also intended to include the plural forms unless the context indicates otherwise. It should be further understood that the terms "comprise", "include" indicate the presence of the stated features, operations, elements, components, items, kinds, and / or groups, but do not exclude the presence, occurrence, or addition of one or more other features, operations, elements, components, items, kinds, and / or groups. The terms "or" and "and / or" used herein are interpreted as inclusive, or meaning any one or any combination. Thus, "A, B, or C" or "A, B, and / or C" means "any one of the following: A; B; C; A and B; A and C; B and C; A, B, and C". An exception to this definition only occurs when the combination of elements, functions, or operations is inherently mutually exclusive in some way.

[0028] A single-cell voltage inspection module for a fuel cell stack of the present invention realizes voltage detection of the single cells of the stack by means of a stack single-cell voltage connector, a single-cell voltage detection circuit, an auxiliary power supply circuit, and a communication circuit provided in the inspection module; the present invention provides a low-voltage auxiliary power supply to the inspection module from the stack through the auxiliary power supply circuit, avoiding external auxiliary power supply and simplifying the system; moreover, the detection loop and the power supply loop are respectively connected to the single cells of the stack by non-shared detection lines and power lines, avoiding the influence of the auxiliary power supply current on the detection and improving the detection accuracy and precision.

[0029] The following will be a detailed description of the embodiments of the present invention with reference to the accompanying drawings, so that those skilled in the technical field of the present invention can easily implement it. The present invention can be embodied in many different forms and is not limited to the embodiments described herein.

[0030] As Figure 1 Fig. shows a schematic structural diagram of a single-cell voltage inspection module for a fuel cell stack in an embodiment of the present invention.

[0031] The fuel cell stack is formed by stacking single cells of the stack; the single-cell voltage inspection module for the fuel cell stack is used to detect the voltage of the single cells of the stack stacked in the stack; the potentials of the single cells of the stack stacked in the stack show an increasing or decreasing trend in sequence; under normal circumstances, the voltages of each single cell of the stack should be basically the same.

[0032] The single-cell voltage inspection module for the fuel cell stack includes: a stack single-cell voltage connector 1, a single-cell voltage detection circuit 2, an auxiliary power supply circuit 3, and a communication circuit 4;

[0033] The stack single-cell voltage connector 1 is used to connect multiple single cells of the stack respectively through detection lines;

[0034] The single-cell voltage detection circuit 2 is connected to the stack single-cell voltage connector 1 and is used to detect the voltage of each connected single cell of the stack through multiple detection channels to obtain corresponding voltage detection data;

[0035] The auxiliary power supply circuit 3 is connected to the single-cell voltage detection circuit 2 and the communication circuit 4 and is provided with a power connector 31, which is used to connect specific single cells of the stack through the power connector 31 through power lines to supply power to the circuits in the inspection module; the specific single cells of the stack are two single cells of the stack connected by the stack single-cell voltage connector 1. Preferably, the specific single cells of the stack are the cathode of the single cell with the highest potential and the anode of the single cell with the lowest potential among all the single cells of the stack connected by the stack single-cell voltage connector 1.

[0036] The communication circuit 4 is connected to the single-cell voltage detection circuit 2, and is used to transmit the voltage detection data of each stack single-cell battery to the outside, and at the same time obtain instructions from the outside. Common communication methods include CAN, RS485, RS232, SPI and other methods.

[0037] The inspection module of the present invention is powered by the stack, and is connected to a specific single cell of the stack through a connector to obtain power from the stack for the auxiliary power supply circuit, avoiding the need to obtain an auxiliary power supply that needs to be isolated from the outside; the power supply line and the detection line are separately arranged to avoid detection errors caused by the voltage drop of the supply current on the line.

[0038] In one embodiment, the single-cell voltage detection circuit 2 is a circuit for converting the voltage of the stack single cell connected by the stack single-cell voltage connector 1, and mainly includes an analog-to-digital conversion (ADC) function inside, and may also include functions such as filtering and amplification. These functions can be realized by a dedicated chip or by a microprocessor plus peripheral circuits.

[0039] The single-cell voltage detection circuit 2 has multiple detection channels, and each detection channel is an analog-to-digital conversion channel, which is used to convert the voltage signals input to the corresponding channels into digital signals to obtain the corresponding voltage detection data.

[0040] In one embodiment, the stack single-cell voltage connector 1 includes: single-cell voltage connection terminals arranged in one-to-one correspondence with each detection channel; each single-cell voltage connection terminal is used to connect one or more stack single-cell batteries, so that the voltage signals of the connected stack single-cell batteries are input to the corresponding detection channels for voltage detection. The number of stack single-cell batteries that each single-cell voltage detection terminal can connect corresponds to the number of channels detected by the voltage detection circuit.

[0041] Specifically, the implementation method of connecting a single stack single-cell battery is that each single-cell voltage connection terminal is respectively connected to a stack single-cell battery; the implementation method of connecting multiple stack single-cell batteries is that each single-cell voltage connection terminal connects the stack single-cell batteries at intervals of multiple stack single-cell batteries; for example, if each single-cell voltage connection terminal is connected to two stack single-cell batteries, then the single-cell voltage connection terminal connects the stack single-cell batteries at intervals of one stack single-cell battery in the stack, and voltage sampling is performed in the way of collecting one voltage every other one, that is, each collected voltage is the voltage of two single cells.

[0042] In one embodiment, as Figure 2 , the power connector 31 is provided with two power terminals, which are respectively connected to two single cells of the stack to form the positive and negative poles of the auxiliary power supply, including:

[0043] The positive power supply terminal 311 is used to connect, through a power line, the cathode of the single cell battery with the highest potential among all the single cell batteries connected by the single cell voltage connector 1 of the stack.

[0044] The negative power supply terminal 312 is used to connect, through a power line, the anode of the single cell battery with the lowest potential among all the single cell batteries connected by the single cell voltage connector 1 of the stack.

[0045] In one embodiment, each single cell battery of the stack is composed of a membrane electrode sandwiched by battery bipolar plates. In order to detect the single cell voltage, at least two connection parts are usually designed on the bipolar plate. It should be noted that the connection part can be any device with electrical connection function, such as connection component structures like terminals, contact points, and connection holes, etc. For example, an elastic terminal is inserted into the opening on the plate, or a telescopic probe is used to contact the plane of the bipolar plate, etc. Their functions are all to establish an electrical connection between the wire and the bipolar plate.

[0046] Among them, the functional types of the connection parts include: voltage detection connection parts and power supply connection parts; and among them, the voltage detection connection parts are used to connect with the single cell voltage connection terminals of the single cell voltage connector of the stack through detection lines; the power supply connection parts are used to connect with the power supply terminals of the power supply connector through power lines.

[0047] For example, Figure 3 shows a situation with two connection terminals. There are two connection parts 201 on the bipolar plate 200 of the single cell battery of the stack. The single cell voltage connector and the power supply connector can simultaneously have two independent external wires and connectors 202 to make electrical connections with the single cell battery through 201.

[0048] It should be noted that although at least two connection parts are provided on each single cell battery of the stack, not every connection part is actually connected to a wire. One of the voltage detection connection parts is connected to the detection line. The two single cell batteries with the highest and lowest potentials of the single cell battery to be measured are respectively connected to the power lines, and the power lines and the detection lines are connected to different connection positions of the single cell battery. During operation, even if there is a relatively large resistance in the single cell voltage connection terminal and the connection part, since the current passing through it is extremely small, there will be no obvious difference in the voltage at both ends, thus ensuring that the detection circuit has high detection accuracy and precision; if there is a relatively large resistance in the single cell voltage connection terminal and the connection wire, since the current passing through it is relatively large, a relatively large voltage drop may be caused, but since the available range of power supply is relatively wide, the voltage drop on the line generally has no impact.

[0049] In one embodiment, if the voltage between two power terminals is within the normal operating range, it can directly supply power to other circuits; otherwise, the voltage between the two power terminals needs to be converted into the voltage required by other circuits.

[0050] For example Figure 2 , the auxiliary power supply circuit 3 further includes: a power conversion device 32, configured to convert the voltage between the positive power terminal and the negative power terminal of the power connector 1 into the normal operating range when the voltage is not within the normal operating range, so as to supply power to the circuits in the inspection module after conversion.

[0051] It should be noted that a non-isolated converter can be used, which is simple in circuit, high in efficiency and low in cost compared with an isolated converter.

[0052] Similar to the principle of the above embodiment, the present invention provides a fuel cell stack single-cell voltage inspection system.

[0053] Specific embodiments are provided below in conjunction with the accompanying drawings:

[0054] For example Figure 4 Shows a schematic structural diagram of a fuel cell stack single-cell voltage inspection system in an embodiment of the present invention.

[0055] The system includes: a plurality of stack single-cell batteries 200 stacked on the stack, one or more fuel cell stack single-cell voltage inspection modules 100, and a controller 300; it should be noted that the fuel cell stack single-cell voltage inspection module 100 can implement the structure and functions as Figure 1 Therefore, it will not be elaborated here. For the sake of convenience of description, Figure 4 Only one fuel cell stack single-cell voltage inspection module is taken as an example here, and this is not limited.

[0056] Among them, at least one voltage detection connection part and at least one power connection part are arranged on the bipolar plate of each stack single-cell battery 200; the voltage detection connection part is used to connect to the single-cell voltage connection terminal of the stack single-cell voltage connector 1 through the detection line 01; the power connection part is used to connect to the two power terminals 311 or 312 of the power connector 2 through the power line 02.

[0057] The number of the single-cell voltage inspection modules 100 of the fuel cell stack corresponds to the number of the single cells 200 of the stack to be measured; among them, each single-cell voltage inspection module 100 of the fuel cell stack has the maximum number of single cells of the stack that can be connected based on the detection requirements and the set number of detection channels; if the number of single cells of the stack to be detected does not exceed the maximum number, one single-cell voltage inspection module of the fuel cell stack can be used for sampling; if it exceeds the maximum number, more than two single-cell voltage inspection modules of the fuel cell stack are selected for sampling; that is, if the number of single cells to be detected is large, more of the said inspection modules can be used in combination for convenient expansion.

[0058] The system uses each single-cell voltage inspection module 100 powered by the stack to detect the voltages of the connected single cells 200 of the stack, and sends the obtained voltage detection data of each single cell 200 of the stack to the controller 300. Adopting an isolated communication method, each single-cell voltage inspection module 100 can communicate with the controller 300. Preferably, a communication method with a bus structure is adopted, which can reduce the wiring.

[0059] The following specifically describes the specific implementation manners in the cases of setting one single-cell voltage inspection module of the fuel cell stack and multiple single-cell voltage inspection modules of the fuel cell stack.

[0060] For the case where the number of single cells of the stack to be detected does not exceed the maximum number and one single-cell voltage inspection module of the fuel cell stack is used for sampling, the following specific embodiments are now combined with Figure 4 for description.

[0061] In one embodiment, as Figure 4 shown, multiple detection lines 01 connect the single cells 201 to be measured of the stack to the single-cell voltage connection terminals in the single-cell voltage connector 1, and are respectively connected to multiple analog-to-digital conversion channels inside the inspection module to realize the sampling of the single-cell voltage; then the communication circuit transmits the obtained voltage signal to the controller 300 through a communication method, and at the same time obtains an instruction from the controller 300. Two power lines 02 respectively connect the single cell with the lowest potential in the single cells of the stack to be measured to the negative power terminal 312 of the power connector, and connect the single cell with the highest potential in the single cells of the stack to be measured to the positive power terminal 311 of the power connector, and provide an auxiliary power supply for the voltage inspection module 100, and perform voltage conversion through a power converter if necessary.

[0062] For the case where the number of single cells of the stack to be detected exceeds the maximum number and multiple single-cell voltage inspection modules of the fuel cell stack are used for sampling, the following specific embodiments are now combined with Figure 5 and Figure 6 for description.

[0063] In one embodiment, as Figure 5 , when there are multiple fuel cell stack single-cell voltage inspection modules, each stack single-cell 200 of the fuel cell stack is divided into single-cell groups that are the same in number as and arranged continuously with the number of fuel cell stack single-cell voltage inspection modules according to the stacking order, and each single-cell group corresponds to the number of fuel cell stack single-cell voltage inspection modules; for the same number of fuel cell stack single-cell voltage inspection modules, the number of voltages to be measured in each group should not be greater than the number of sampling channels of a single inspection module.

[0064] Among them, each fuel cell stack single-cell voltage inspection module 100 is connected to all the stack single-cells 200 of the corresponding single-cell group, and is also connected to the stack single-cells 200 adjacent to this single-cell group in order to continuously collect the single-cell voltage; since the potentials of the multiple stack single-cells 200 stacked on the fuel cell stack show an increasing or decreasing trend in sequence, therefore, the stack single-cells 200 located in other single-cell groups and adjacent to the current single-cell group that are connected are respectively lower and higher in potential than all the stack single-cells of the current single-cell group, that is, the stack single-cell 200 with the highest potential and the stack single-cell 200 with the lowest potential among all the stack single-cells connected to the current fuel cell stack single-cell voltage inspection module 100 are connected to the corresponding power terminals of the power connector.

[0065] It should be noted that the method of sampling each single-cell voltage through multiple fuel cell stack single-cell voltage inspection modules 100 is similar to the method of sampling each single-cell voltage with a single fuel cell stack single-cell voltage inspection module, so it will not be elaborated here. In actual design, two or more inspection modules can be included on one circuit board without changing the basic principle of the present invention.

[0066] In a specific embodiment, a way for the fuel cell stack single-cell voltage inspection module 100 to be connected to the stack single-cells adjacent to the single-cell group: as Figure 5 , the stack single-cell voltage connector 1 and the power connector of each fuel cell stack single-cell voltage inspection module 100 are respectively connected to the voltage detection connection part and the power connection part of the stack single-cells adjacent to the corresponding single-cell group through the detection line 01 and the power line 02; specifically, the single-cell voltage connection terminals of the stack single-cell voltage connector 1 of each fuel cell stack single-cell voltage inspection module 100 are connected to the voltage detection connection part of the adjacent stack single-cells through the detection line 01; the two power terminals of the stack power connector of each fuel cell stack single-cell voltage inspection module 100 are connected to the power connection part of the adjacent stack single-cells through the power line 02.

[0067] In a specific embodiment, for the convenience of assembly, the connection lines with a common monolithic structure may also be connected between the inspection modules instead of branching from the monolithic cells of the stack. Another way for the fuel cell stack monolithic voltage inspection module to connect with the monolithic cells of the stack adjacent to the monolithic battery pack is as follows: Figure 6 , the monolithic voltage connector and the power connector of each fuel cell stack monolithic voltage inspection module 100 are respectively connected to the monolithic voltage connector and the power connector of the fuel cell stack monolithic voltage inspection module 100 corresponding to the monolithic battery pack adjacent to the corresponding monolithic battery pack through the detection line 01 and the power line 02; specifically, the monolithic voltage connection terminal of the monolithic voltage connector of each fuel cell stack monolithic voltage inspection module 100 is connected to the monolithic voltage connection terminal of the monolithic voltage connector of the fuel cell stack monolithic voltage inspection module 100 corresponding to the monolithic battery pack adjacent to the corresponding monolithic battery pack through the detection line 01; the two power terminals of the power connector of each fuel cell stack monolithic voltage inspection module 100 are connected to the two power terminals of the fuel cell stack monolithic voltage inspection module 100 corresponding to the monolithic battery pack adjacent to the corresponding monolithic battery pack through the power line 02.

[0068] To better illustrate the above fuel cell stack monolithic voltage inspection module and system, the present invention provides the following specific embodiments.

[0069] Embodiment 1: A fuel cell inspection module.

[0070] The fuel cell inspection module includes: a monolithic voltage connector, a monolithic voltage detection circuit, an auxiliary power supply circuit, and an external communication circuit;

[0071] The monolithic voltage detection circuit includes a microprocessor MCU as the core for voltage sampling and data processing. This MCU has 24 ADC sampling channels. The monolithic voltage connection terminal includes 25 pins, and the lowest pin is connected to the reference ground level of the entire inspection module. During application, this pin is connected to the lowest potential in the measured fuel cell stack monolithic battery pack through the detection line; it should be noted that the actual physical connection terminal on the stack may be the anode bipolar plate of the lowest monolithic cell or the cathode bipolar plate of the adjacent monolithic cell in contact with it. The remaining 24 pins of the monolithic voltage connection terminal are sequentially connected to the cathodes of the respective monolithic cells of the measured monolithic battery pack. Inside the monolithic voltage detection circuit, there are 24 differential amplifier circuits, which respectively perform differential amplification on the differences between adjacent two levels among the 25 introduced levels, a total of 24 voltages. The amplified voltages enter the ADC sampling unit of the MCU to obtain the sampling values of 24 voltages. After calculation and calibration by the MCU, the digital quantities of 24 detected monolithic voltages are obtained.

[0072] The functional part of the communication circuit is included in the MCU, and the peripheral CAN communication module of the MCU is used to form a CAN communication signal. The communication circuit also includes a CAN transceiver and a signal isolation circuit.

[0073] The positive pole of the power supply terminal is connected to the single cell with the highest potential of the single cell battery pack under test through a power line, and the negative pole of the power supply terminal is connected to the lowest potential of the single cell battery pack under test through a power line. The power line and the detection line are connected to different connection terminals of the single cell of the stack through different wires, thus avoiding the influence of the power supply current on the detection accuracy and accuracy.

[0074] Since the maximum voltage between the two power supply terminals can reach more than 24V, while the voltage required by circuits and devices such as the MCU is 5V, a step-down power conversion circuit is needed to convert the input voltage to 5V. Here, a low-cost non-isolated power conversion circuit is adopted.

[0075] Embodiment 2: A fuel cell inspection module.

[0076] The fuel cell inspection module includes: a single cell voltage connector of the stack, a single cell voltage detection circuit, an auxiliary power supply circuit, and an external communication circuit;

[0077] The single cell voltage detection circuit includes a dedicated voltage detection chip LTC6804-1 and its peripheral circuit. The stack contains 24 single cells, and voltage sampling is carried out in the way of collecting one voltage every other one, that is, each collected voltage is the voltage of two single cells. The chip LTC6804-1 has 12 sampling channels. The single cell voltage connection terminal 102 includes 13 pins, among which the pin with the lowest potential is connected to the ground of the circuit inside the circuit and is connected to the anode of the single cell with the lowest potential of the single cell battery pack under test outside. The remaining 12 pins are connected to the cathode potentials of the 12 single cells under test. Each connected single cell voltage signal is filtered by a resistor and a capacitor and then connected to the voltage sampling pin of the chip LTC6804-1, and the sampling result of the voltage is obtained through analog-to-digital conversion inside the LTC6804.

[0078] LTC6804 also has a communication interface called isoSPI, which is used to achieve high-speed communication and can realize the isolation of communication signals through a micro magnetic isolation element. When there are multiple inspection modules, the communications of all modules can be connected together to form a daisy chain connection, and the communication structure of the whole system is very simple.

[0079] Since the power supply input range of LTC6804-1 is as high as 75V, while the highest power supply input is about 24V, a power conversion circuit is not needed, and it can be directly powered by the voltage input by the voltage terminal.

[0080] Embodiment 3: A single cell voltage inspection system.

[0081] 118 single cells stacked on the stack are voltage sampled in a way that one voltage is sampled every other cell, that is, each sampled voltage is the voltage of two single cells. A total of 59 sampling channels are required, and 5 voltage inspection modules are configured. One inspection module detects 11 channels, and the remaining inspection modules detect 12 channels each.

[0082] Each bipolar plate of the single cell of the stack has two connection positions, which are used for the detection connection part and the power supply connection part respectively. Because of the way of voltage sampling that one voltage is sampled every other cell, only some single cells need to be sampled. The detection connection part of the bipolar plate of the cell to be sampled is connected to the detection terminal of the inspection module through a detection line, and for the bipolar plate of the cell that needs to connect the power supply line, the power supply line is connected to the power supply connection part. The remaining unused connection terminals on the stack bipolar plate are left vacant without any connection.

[0083] It also includes a controller, which contains a general microcontroller MCU and a dedicated communication chip. The MCU communicates with the communication chip in SPI mode to send setting commands and obtain sampling data. The communication chip converts the signal into the isoSPI communication mode compatible with LTC6804-1, and isolates the signal through a magnetic component, and is connected to one end of the communication bus in daisy chain form. Each inspection module has a unique address identifier to represent its identity and distinguish the position of the single-cell voltage group it samples. In this way, the voltage inspection of the entire stack is realized.

[0084] The present invention has the following advantages compared with the prior art:

[0085] 1. Utilize the stack to provide the low-voltage auxiliary power supply for the inspection module, avoiding external auxiliary power supply and simplifying the system; at the same time, avoid using a converter with isolation function, reducing the cost;

[0086] 2. By designing no less than one contact position on each group of single cells of the stack, the detection loop and the power supply loop between the single cell and the inspection module respectively use non-shared detection lines and power supply lines, and are connected to different contact positions of the stack single cell, thus avoiding the influence of the auxiliary power supply current on the detection and improving the detection accuracy and precision.

[0087] In summary, the single-cell voltage inspection module and system of the fuel cell stack of the present invention achieve voltage detection of the single cells of the stack by setting a stack single-cell voltage connector, a single-cell voltage detection circuit, an auxiliary power supply circuit, and a communication circuit in the inspection module; the present invention provides a low-voltage auxiliary power supply to the inspection module from the stack through the auxiliary power supply circuit, avoiding external auxiliary power supply and simplifying the system; and the detection loop and the power supply loop are respectively connected to the single cells of the stack by non-shared detection lines and power lines, avoiding the influence of the auxiliary power supply current on the detection and improving the detection accuracy and precision. Therefore, the present invention effectively overcomes various disadvantages in the prior art and has high industrial utilization value.

[0088] The above embodiments are only used to exemplarily illustrate the principles and effects of the present invention, rather than to limit the present invention. Any person familiar with this technology can modify or change the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or changes completed by those with ordinary knowledge in the technical field without departing from the spirit and technical ideas disclosed by the present invention should still be covered by the claims of the present invention.

Claims

1. A single-cell voltage inspection module for a fuel cell stack, characterized in that Used for voltage detection of single cells in a stack, including: a single cell voltage connector for the stack, a single cell voltage detection circuit, an auxiliary power supply circuit, and a communication circuit; Among them, the single cell voltage connector for the stack is used to connect multiple single cells in the stack respectively through detection lines; The single cell voltage detection circuit is connected to the single cell voltage connector for the stack and is used to perform voltage detection on each connected single cell in the stack through multiple detection channels to obtain corresponding voltage detection data; The auxiliary power supply circuit is connected to the single cell voltage detection circuit and the communication circuit, and is provided with a power connector, which is used to connect specific single cells in the stack through a power line respectively by the power connector to supply power to the circuits in the inspection module; The communication circuit is connected to the single cell voltage detection circuit and is used to transmit the voltage detection data of each single cell in the stack to the outside.

2. The single-cell voltage inspection module of the fuel cell stack according to claim 1, characterized in that The single cell voltage detection circuit has multiple detection channels, and each detection channel is an analog-to-digital conversion channel, which is used to convert each voltage signal input to the corresponding channel into a digital signal to obtain corresponding voltage detection data.

3. The single-cell voltage inspection module of the fuel cell stack according to claim 1, wherein The single cell voltage connector for the stack includes: single cell voltage connection terminals arranged in one-to-one correspondence with each detection channel; Each single cell voltage connection terminal is used to connect one or more single cells in the stack, so that the voltage signal of the connected single cells in the stack can be input to the corresponding detection channel for voltage detection.

4. The single cell voltage inspection module of the fuel cell stack according to claim 3, characterized in that The power connector is provided with two power terminals, including: The positive power terminal is used to connect the cathode of the single cell with the highest potential among all the single cells in the stack connected by the single cell voltage connector for the stack through a power line; The negative power terminal is used to connect the anode of the single cell with the lowest potential among all the single cells in the stack connected by the single cell voltage connector for the stack through a power line.

5. The single cell voltage inspection module of the fuel cell stack according to claim 4, characterized in that, At least two connection parts are arranged on the bipolar plate of each single cell in the stack; among them, the types of connection parts include: voltage detection connection parts and power connection parts; And among them, the voltage detection connection part is used to connect with the single cell voltage connection terminal of the single cell voltage connector for the stack through a detection line; the power connection part is used to connect with the power terminal of the power connector through a power line.

6. The single cell voltage inspection module of the fuel cell stack according to claim 4, characterized in that, The auxiliary power supply circuit further includes: a power conversion device, which is used to convert the voltage between the positive power terminal and the negative power terminal of the power connector into the normal working range when the voltage is not in the normal working range, so as to supply power to the circuits in the inspection module after conversion.

7. A single-cell voltage inspection system for a fuel cell stack, characterized in that, The system includes: Multiple single cells in the stack stacked on the stack, one or more fuel cell single cell voltage inspection modules as described in any one of claims 1 to 6, and a controller; Among them, the number of the fuel cell single cell voltage inspection modules is corresponding to the number of the single cells to be measured; at least one voltage detection connection part and at least one power connection part are arranged on the bipolar plate of each single cell; Each fuel cell single cell voltage inspection module powered by the stack performs voltage detection on each connected single cell in the stack, and sends the obtained voltage detection data of each single cell in the stack to the controller.

8. The single-cell voltage inspection system for a fuel cell stack according to claim 7, wherein When there are multiple single-cell voltage inspection modules for the fuel cell stack set, each single-cell battery of the fuel cell stack is divided into single-cell battery groups that are the same in number as and arranged continuously with the number of single-cell voltage inspection modules for the fuel cell stack according to the stacking order, and each single-cell battery group corresponds to a single-cell voltage inspection module for the fuel cell stack; Among them, each single-cell voltage inspection module for the fuel cell stack is connected to all the single-cell batteries of the corresponding single-cell battery group, and is also connected to the single-cell batteries of the fuel cell stack adjacent to the single-cell battery group.

9. The single cell voltage inspection system of the fuel cell stack according to claim 8, wherein, The single-cell voltage connector and the power connector of each single-cell voltage inspection module for the fuel cell stack are respectively connected to the voltage detection connection part and the power connection part of the single-cell batteries of the fuel cell stack adjacent to the corresponding single-cell battery group through the detection line and the power line.

10. The single-cell voltage inspection system of the fuel cell stack according to claim 8, characterized in that, The single-cell voltage connector and the power connector of each single-cell voltage inspection module for the fuel cell stack are respectively connected to the single-cell voltage connector and the power connector of the single-cell voltage inspection module for the fuel cell stack corresponding to the single-cell battery group adjacent to the corresponding single-cell battery group through the detection line and the power line.

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