A protection device and control method for preventing high-potential corrosion of a hydrogen fuel cell stack

Abstract

The present invention discloses a protection device and control method for preventing high-potential corrosion of a hydrogen fuel cell stack, which relates to the technical field of fuel cells. It includes a stack module, a switch array module, and a voltage comparison and gating module. The stack module is provided with at least two groups of single-cell batteries. The switch array module is provided with at least two groups of parallel switch combinations. Each end point of the head and tail of each single-cell battery is respectively connected to a group of switch combinations. The voltage comparison and gating module is provided with voltage-dividing resistors connected in series in sequence. The voltage comparison and gating module is provided with a discharge module. The discharge module is provided with at least one discharge resistor R. Voltage comparators A, B, and C connect the voltage of the selected and conducted single-cell battery to the discharge resistor R for discharging. In the protection device for preventing high-potential corrosion of a hydrogen fuel cell stack in the present invention, each single-cell battery in the stack is periodically conducted and detected according to the conduction time, and selected and discharged, so as to keep the voltage of the fuel cell stack uniformly decreasing and presenting a stable change state.

Description

Technical Field

[0001] The present invention relates to the technical field of fuel cells, and particularly to a protection device and a control method for preventing high-potential corrosion of a hydrogen fuel cell stack. Background Art

[0002] A hydrogen fuel cell mainly consists of a bipolar plate, a membrane electrode assembly, and a current collector plate. Its power generation principle is to control the electrochemical reaction of hydrogen and oxygen to convert the chemical energy of the reactants into electrical energy, while generating water and heat. Since hydrogen and air are continuously supplied to the hydrogen fuel cell, electricity and water are continuously generated. After the fuel cell engine shuts down, due to the uneven distribution of hydrogen and air in each cell of the anode and cathode, the voltage of each single fuel cell will be uneven, as shown in the attached drawing Figure 2 As shown. The voltage of some single cells is relatively low, and the voltage of some single cells is relatively high. High potential for a long time is likely to cause carbon carrier corrosion and reduce the performance of the fuel cell. Especially during start-stop, the potential will reach more than 1V, which will accelerate the corrosion of the C carrier.

[0003] The traditional method for preventing high potential is to connect a resistor in series outside the fuel cell. This method can reduce the fuel cell voltage, but the voltage potential of each cell of the fuel cell is different. Using a single resistor will cause the voltage of the low-potential single cell to be even lower, and the voltage of the high-potential single cell will not drop enough. Therefore, there is an urgent need for a protection device for preventing high-potential corrosion of a hydrogen fuel cell stack to meet the long-life requirements of the fuel cell. Summary of the Invention

[0004] Aiming at the defects existing in the prior art, the purpose of the present invention is to provide a protection device and a control method for preventing high-potential corrosion of a hydrogen fuel cell stack, aiming to solve the technical problems in the related art to a certain extent.

[0005] To achieve the above purpose, the technical solution adopted by the present invention is:

[0006] A protection device for preventing high-potential corrosion of a hydrogen fuel cell stack includes a stack module, a switch array module, and a voltage comparison and gating module. The stack module is provided with at least 2 groups of single cells. The switch array module is provided with at least 2 groups of parallel switch combinations. Each switch combination has two parallel switches. The head and tail endpoints of each single cell are respectively connected to a group of switch combinations. The voltage comparison and gating module is provided with voltage-dividing resistors R1, R2, R3, and R4 connected in series in sequence. The voltage-dividing resistor R1 is connected to the stack module through the switch array module. The voltage-dividing resistors R1, R2, and R3 are respectively connected in parallel with voltage comparators A, B, and C. The voltage comparators A, B, and C are respectively connected to a latch;

[0007] The voltage comparison gating module is provided with a discharging module, and the discharging module is provided with at least one discharging resistor R. The voltage comparators A, B, and C connect the selected and conducted single-cell voltages to the discharging resistor R for discharging.

[0008] On the basis of the above technical solution, the discharging module is provided with transistors a, b, and c. The emitters of transistors a, b, and c are respectively connected to a discharging resistor R, and the collectors of transistors a, b, and c are respectively connected to the switch array module. Among them, transistors a, b, and c are respectively connected in series with transistors 1a, 2b, and 3c through the discharging resistor R. The voltage comparators A, B, and C are correspondingly connected to the bases of transistors a, b, and c and the bases of transistors 1a, 2b, and 3c through a latch, and the emitters of transistors 1a, 2b, and 3c are grounded.

[0009] On the basis of the above technical solution, transistors a, b, and c and transistors 1a, 2b, and 3c are NPN-type bipolar junction transistors.

[0010] On the basis of the above technical solution, one end of the voltage-dividing resistor R4 is grounded, and one end of the voltage-dividing resistor R1 is connected to the reference signal power supply.

[0011] On the basis of the above technical solution, the number of switch combinations in the switch array module corresponds to the number of single cells in the stack module.

[0012] On the basis of the above technical solution, the switch combination is two parallel opto-relays.

[0013] On the basis of the above technical solution, the latch is a latch with enable control.

[0014] On the basis of the above technical solution, the resistance value and power of the discharging resistor R are set accordingly according to the model of the stack module.

[0015] On the basis of the above technical solution, the voltage-dividing resistors R1, R2, R3, and R4 are set with three voltage nodes of 0.1V, 0.4V, and 0.8V and the corresponding resistor values are set.

[0016] On the basis of the above technical solution, a control method for a protection device for preventing high-potential corrosion of a hydrogen fuel cell stack includes the following steps:

[0017] Step 1: Encoding the switch combinations in the switch array module respectively, and sequentially marking them as (k1, k11), (k2, k22), (k3, k33),..., (kn, knn), [kn + 1, k(n + 1)(n + 1))], and each group of two switches is respectively connected to both ends of a single cell;

[0018] Step 2: Setting the conduction structure of the switch array module, and setting the single-cell voltage signal collected when turned on as Vin.

[0019] When Vin > 0.8V, all discharge resistors R are selected for discharging, and voltage comparators A, B, and C are controlled to output high levels. Transistors a, b, c, 1a, 2b, and 3c are all turned on, which is set as the first-stage discharge rate and rapid consumption is performed;

[0020] When 0.8V > Vin > 0.8V (it should be noted that this condition seems incorrect, assuming it's a typo and should be 0.4V > Vin > 0.1V), any two discharge resistors R are selected for discharging. Voltage comparator A outputs a low level, voltage comparator B outputs a high level, and voltage comparator C outputs a high level. Transistors a and 1a are not turned on, and transistors b, c, 2b, and 3c are turned on, which is set as the second-stage discharge rate and general-rate consumption is performed;

[0021] When 0.4V > Vin > 0.1V, any one discharge resistor R is selected for discharging. Voltage comparator A outputs a low level, voltage comparator B outputs a low level, and voltage comparator C outputs a high level. Transistors a, b, 1a, and 2b are not turned on, and transistors c and 3c are turned on, which is set as the third-stage discharge rate and slow consumption is performed;

[0022] When Vin < 0.1V, voltage comparators A, B, and C all output low levels, transistors a, b, c, 1a, 2b, and 3c are all not turned on, and all discharge resistors R do not consume;

[0023] Step 3: Set the conduction time of the on-switch combination. From k1 to k(n + 1) being turned on in sequence is one cycle, and the discharge operation is controlled accordingly;

[0024] Step 4: According to the pre-set voltage fluctuation value, after rapid periodic cyclic conduction and discharge, the voltage of the fuel cell stack drops uniformly, and the protection device is turned off.

[0025] Compared with the prior art, the advantages of the present invention are as follows:

[0026] A protection device for preventing high-potential corrosion of a hydrogen fuel cell stack in the present invention can avoid the corrosion phenomenon when the hydrogen fuel cell stack is in a high-potential state compared with the prior art, and balance the voltage of each single cell of the fuel cell.

[0027] A control method for a protection device for preventing high-potential corrosion of a hydrogen fuel cell stack in the present invention performs periodic conduction detection and gated discharge on each single cell in the stack according to the conduction time. Through rapid periodic cyclic conduction and discharge, the voltage of the fuel cell stack is kept dropping uniformly, showing a stable change state. Description of the Drawings

[0028] Figure 1 It is a schematic structural diagram of a protection device for preventing high-potential corrosion of a hydrogen fuel cell stack in an embodiment of the present invention;

[0029] Figure 2 This is the single-cell voltage distribution diagram without discharge after the fuel cell engine shuts down in the embodiment of the present invention;

[0030] Figure 3 This is the single-cell voltage distribution diagram obtained after discharge after the fuel cell engine shuts down in the embodiment of the present invention;

[0031] Figure 4 This is a schematic structural diagram of a protection device for preventing high-potential corrosion of a hydrogen fuel cell stack in the embodiment of the present invention. Embodiment

[0032] The following further elaborates on the embodiments of the present invention with reference to the accompanying drawings.

[0033] Here, the exemplary embodiments will be described in detail, and the examples are shown in the accompanying drawings. When the following description refers to the drawings, unless otherwise indicated, the same numbers in different drawings represent the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the present disclosure. On the contrary, they are merely examples of devices and methods consistent with some aspects of the present disclosure as detailed in the appended claims. The terms used in the present disclosure are only for the purpose of describing specific embodiments and are not intended to limit the present disclosure. The singular forms "a", "the", and "said" used in the present disclosure and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise. It should also be understood that the term "and / or" used herein refers to and includes any or all possible combinations of one or more of the associated listed items.

[0034] In the description of this application, it should also be noted that, unless otherwise clearly specified and defined, the terms "arranged", "installed", "connected", and "coupled" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the internal communication of two elements. For those of ordinary skill in the art, the specific meanings of the above terms in this application can be understood according to specific circumstances. Moreover, the terms "comprising", "including", or any other variation thereof are intended to cover non-exclusive inclusion, so that a process, method, article, or device including a series of elements not only includes those elements but also includes other elements not explicitly listed, or also includes elements inherent to such a process, method, article, or device. Without further limitation, the element defined by the statement "including one..." does not exclude the existence of other identical elements in the process, method, article, or device including the said element.

[0035] SeeFigure 1 The structural schematic diagram of a protection device for preventing high-potential corrosion of a hydrogen fuel cell stack in an embodiment of the present invention is shown. It includes a stack module, a switch array module, and a voltage comparison and selection module. The stack module is provided with at least 2 groups of single cells. The switch array module is provided with at least 2 groups of parallel switch combinations. Each switch combination has two parallel switches. The head and tail endpoints of each single cell are respectively connected to a group of switch combinations. The voltage comparison and selection module is provided with voltage-dividing resistors R1, R2, R3, and R4 connected in series in sequence. The voltage-dividing resistor R1 is connected to the stack module through the switch array module. The voltage-dividing resistors R1, R2, and R3 are respectively connected in parallel with voltage comparators A, B, and C. The voltage comparators A, B, and C are respectively connected to a latch.

[0036] See Figure 4 The structural schematic diagram of a protection device for preventing high-potential corrosion of a hydrogen fuel cell stack in an embodiment of the present invention is shown. The voltage comparison and selection module is provided with a discharge module. The discharge module is provided with at least one discharge resistor R. The voltage comparators A, B, and C connect the voltage of the selected and conducted single cell to the discharge resistor R for discharging.

[0037] In this embodiment, the discharge module is provided with transistors a, b, and c. The emitters of the transistors a, b, and c are respectively connected to a discharge resistor R. The collectors of the transistors a, b, and c are respectively connected to the switch array module. Among them, the transistors a, b, and c are respectively connected in series with transistors 1a, 2b, and 3c through the discharge resistor R. The voltage comparators A, B, and C are respectively connected to the bases of the transistors a, b, and c and the bases of the transistors 1a, 2b, and 3c through latches. The emitters of the transistors 1a, 2b, and 3c are grounded. If the discharge resistor R is increased, the number of transistors can be correspondingly increased to expand the discharge capacity of the stack protection device in this application and match different power and requirement stacks.

[0038] In this embodiment, the transistors a, b, and c and the transistors 1a, 2b, and 3c are NPN-type bipolar transistors. In some other embodiments, PNP-type bipolar transistors or MOS transistors can also be selected, but the circuit structure needs to be correspondingly adjusted, or other electronic devices with control on-off functions can be selected.

[0039] In this embodiment, one end of the voltage-dividing resistor R4 is grounded, and one end of the voltage-dividing resistor R1 is connected to the reference signal power supply. In addition, according to the technical characteristics of different stack modules, the corresponding signal control voltage and the voltage parameters at both ends of the voltage-dividing resistor can be set.

[0040] In this embodiment, the number of switch combinations corresponds to the number of single cells in the stack module. The switch combination is two parallel opto-relays.

[0041] In this embodiment, the latch is a latch with enable control. In some other embodiments, a logic element with a memory function that changes its state under the action of a specific input pulse level may also be selected, and the circuit structure is adjusted accordingly.

[0042] In this embodiment, the resistance value and power of the discharge resistor R are set according to the model of the stack module.

[0043] In this embodiment, the voltage divider resistors R1, R2, R3, and R4 are set with three voltage nodes of 0.1V, 0.4V, and 0.8V and corresponding resistor values are set. Different voltage nodes can also be set as needed, and the discharge structure and function of the circuit are adjusted accordingly.

[0044] A control method for a protection device against high-potential corrosion of a hydrogen fuel cell stack includes the following steps:

[0045] Step 1: Encoding the switch combinations in the switch array module respectively, and sequentially marking them as (k1, k11), (k2, k22), (k3, k33),..., (kn, knn), [kn+1, k(n+1)(n+1))], and each group of two switches is respectively connected to both ends of a single cell;

[0046] Step 2: Set the conduction structure of the switch array module, and set the single-cell voltage signal collected when it is turned on as Vin. See Figure 2 The figure shows the distribution diagram of the single-cell voltage without discharge after the fuel cell engine stops and shuts down in the embodiment of the present invention;

[0047] When Vin > 0.8V, select all the discharge resistors R for discharge, control the voltage comparators A, B, and C to all output high levels, and the triodes a, b, c, 1a, 2b, and 3c are all turned on, which is set as the first-level discharge rate and is consumed quickly;

[0048] When 0.8V > Vin > 0.8V, select any two discharge resistors R for discharge, control the voltage comparator A to output a low level, the voltage comparator B to output a high level, the voltage comparator C to output a high level, the triodes a and 1a are not turned on, and the triodes b, c, 2b, and 3c are turned on, which is set as the second-level discharge rate and is consumed at a general rate;

[0049] When 0.4V > Vin > 0.1V, select any one discharge resistor R for discharge, control the voltage comparator A to output a low level, the voltage comparator B to output a low level, the voltage comparator C to output a high level, the triodes a, b, 1a, and 2b are not turned on, and the triodes c and 3c are turned on, which is set as the third-level discharge rate and is consumed slowly;

[0050] When Vin < 0.1V, voltage comparators A, B, and C all output low levels, transistors a, b, c, 1a, 2b, and 3c are all non-conductive, and all discharge resistors R do not consume power.

[0051] Step 3: Set the conduction time of the turn-on switch combination. From k1 to k(n + 1) being turned on in sequence is one cycle, and control the discharge operation accordingly.

[0052] Step 4: According to the pre-set voltage fluctuation value, when discharging is performed through fast periodic cycling conduction, the voltage of the fuel cell stack drops uniformly. Refer to Figure 3 The single-cell voltage distribution diagram obtained after discharging after the fuel cell engine shuts down in the embodiment of the present invention is shown. After obtaining a stable voltage, the protection device can be selected to be turned off.

[0053] The following briefly describes an application scenario of an embodiment of the present application: The operation of the switch array is as follows: Taking (k1, k11), (k2, k22), (k3, k33), …, (kn, knn), [kn + 1, k(n + 1)(n + 1))] as each group of switches, the conduction time of each group of switches is turned on at regular intervals. From k1 to k(n + 1) being turned on in sequence is one cycle.

[0054] For example, the working process of the first cell of the fuel cell stack module is as follows: When the signals for turning on k1 and k11 are detected and received, switches k1 and k11 are turned on simultaneously, and the first single cell and the voltage comparison and gating discharge module form a loop. The voltage of the first single cell is fed into the voltage comparator and compared with the voltages of 0.1V, 0.4V, and 0.8V obtained by dividing the voltage through voltage-dividing resistors R1, R2, R3, and R4.

[0055] When the voltage input by the switch array is less than 0.1V, voltage comparators A, B, and C all output low levels, and transistors a, b, c, 1a, 2b, and 3c are all non-conductive, and no resistors consume power.

[0056] When the voltage input by the switch array is greater than 0.1V, voltage comparators A and B both output low levels, voltage comparator C outputs a high level, transistors a, b, 1a, and 2b are all non-conductive, transistors c and 3c are conductive, and one discharge resistor R consumes power, and the voltage drops.

[0057] When the voltage input by the switch array is greater than 0.4V, voltage comparator A outputs a low level, voltage comparators B and C output high levels, transistors a and 1a are all non-conductive, transistors b, c, 2b, and 3b are conductive, and two discharge resistors R consume power, and the voltage drops faster.

[0058] When the voltage input by the switch array is greater than 0.8V, voltage comparators A, B, and C output high levels, and transistors a, b, c, 1a, 2b, and 3c conduct. The three discharge resistors R consume power, and the voltage drops rapidly.

[0059] Those skilled in the art should understand that the embodiments of the present application can be provided as methods, systems, or computer program products. Therefore, the present application can take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware aspects. Moreover, the present application can take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk memories, CD-ROMs, optical memories, etc.) containing computer-usable program code.

[0060] The present application is described with reference to the flowcharts and / or block diagrams of methods, apparatuses (systems), and computer program products according to the embodiments of the present application. It should be understood that each process and / or block in the flowchart and / or block diagram, and the combination of processes and / or blocks in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to the processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing devices to generate a machine, such that the instructions executed by the processor of the computer or other programmable data processing devices generate means for implementing the specified functions in Figure 1 one process or multiple processes and / or blocks Figure 1 one block or multiple blocks.

[0061] The present invention is not limited to the above embodiments. For those of ordinary skill in the art in the technical field of the present invention, without departing from the principle of the present invention, several improvements and refinements can be made, and these improvements and refinements are also considered within the protection scope of the present invention. The content not described in detail in this specification belongs to the prior art well-known to those of ordinary skill in the art.

Claims

1. A protection device for preventing high - potential corrosion of a hydrogen fuel cell stack, characterized in that: It includes a stack module, a switch array module, and a voltage comparison and gating module. The stack module is provided with at least 2 groups of single cells. The switch array module is provided with at least 2 groups of parallel switch combinations. Each switch combination has two parallel switches. The head and tail endpoints of each single cell are respectively connected to a group of switch combinations. The voltage comparison and gating module is provided with voltage-dividing resistors R1, R2, R3, and R4 connected in series in sequence. The voltage-dividing resistor R1 is connected to the stack module through the switch array module. The voltage-dividing resistors R1, R2, and R3 are respectively connected in parallel with voltage comparators A, B, and C. The voltage comparators A, B, and C are respectively connected to a latch; The voltage comparison and gating module is provided with a discharging module. The discharging module is provided with at least one discharging resistor R. The voltage comparators A, B, and C connect the voltage of the single cell selected to be conducted and accessed to the discharging resistor R for discharging; Among them: the discharging module is provided with triodes a, b, and c. The emitters of the triodes a, b, and c are respectively connected to a discharging resistor R. The collectors of the triodes a, b, and c are respectively connected to the switch array module. Among them, the triodes a, b, and c are respectively connected in series with triodes 1a, 2b, and 3c through the discharging resistor R. The voltage comparators A, B, and C are respectively connected to the bases of the triodes a, b, and c and the bases of the triodes 1a, 2b, and 3c through the latch. The emitters of the triodes 1a, 2b, and 3c are grounded.

2. A protection device for preventing high - potential corrosion of a hydrogen fuel cell stack according to claim 1, characterized in that: The triodes a, b, and c and the triodes 1a, 2b, and 3c are NPN-type bipolar transistors.

3. A protection device for preventing high-potential corrosion of a hydrogen fuel cell stack according to claim 1, characterized in that: One end of the voltage-dividing resistor R4 is grounded, and one end of the voltage-dividing resistor R1 is connected to the reference signal power supply.

4. A protection device for preventing high-potential corrosion of a hydrogen fuel cell stack according to claim 1, characterized in that: The number of switch combinations in the switch array module corresponds to the number of single cells in the stack module.

5. A protection device for preventing high-potential corrosion of a hydrogen fuel cell stack according to claim 1, characterized in that: The switch combination is two parallel opto-relays.

6. A protection device for preventing high-potential corrosion of a hydrogen fuel cell stack according to claim 1, characterized in that: The latch is a latch with enable control.

7. A protection device for preventing high-potential corrosion of a hydrogen fuel cell stack according to claim 1, characterized in that: The resistance value and power of the discharging resistor R are set accordingly according to the model of the stack module.

8. A protection device for preventing high-potential corrosion of a hydrogen fuel cell stack according to claim 1, characterized in that: The voltage-dividing resistors R1, R2, R3, and R4 are set with three voltage nodes of 0.1V, 0.4V, and 0.8V and corresponding resistance values are set.

9. A control method for a protection device of a hydrogen fuel cell stack to prevent high-potential corrosion, based on any one of claims 1-8, characterized in that It includes the following steps: Step 1: Encode the switch combinations in the switch array module respectively, and mark them as (k1, k11), (k2, k22), (k3, k33), …, (kn, knn), [kn+1, k(n+1)(n+1))] in sequence. Each group of two switches is respectively connected to both ends of the single cell; Step 2: Set the conduction structure of the switch array module, and set the single voltage signal collected by being turned on as Vin. When Vin > 0.8V, select all the discharging resistors R for discharging, control the voltage comparators A, B, and C to all output high levels, and the triodes a, b, c, 1a, 2b, and 3c are all turned on, which is set as the first-level discharging rate and is quickly consumed; When 0.8V > Vin > 0.4V, select any two discharging resistors R for discharging, control the voltage comparator A to output a low level, the voltage comparator B to output a high level, and the voltage comparator C to output a high level. The triodes a and 1a are not turned on, and the triodes b, c, 2b, and 3c are turned on, which is set as the second-level discharging rate and is consumed at a general rate; When 0.4V > Vin > 0.1V, any number of discharge resistors R are selected for discharging. The voltage comparator A outputs a low level, the voltage comparator B outputs a low level, the voltage comparator C outputs a high level, transistors a, b, 1a, and 2b are not conducting, and transistors c and 3c are conducting. It is set as a three-stage discharge rate and is slowly consumed. When Vin < 0.1V, the voltage comparators A, B, and C all output low levels, transistors a, b, c, 1a, 2b, and 3c are all not conducting, and all discharge resistors R are not consumed. Step 3: Set the conduction time of the on-switch combination. One cycle is from k1 being turned on in sequence to k(n + 1), and the discharging operation is controlled accordingly. Step 4: According to the pre-set voltage fluctuation value, after rapid periodic cyclic conduction and discharging, the voltage of the fuel cell stack drops uniformly, and the protection device is turned off.

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