Voltage inspection method for fusing electrolytic hydrogen production and hydrogen fuel cell stack

Abstract

The invention relates to the technical field of water electrolysis hydrogen production and hydrogen fuel cells, and provides a voltage inspection method for fusing electrolysis hydrogen production and a hydrogen fuel cell stack, which comprises the following steps: S1, setting a synchronous inspection switch which comprises a stack, a scanning relay group, a polarity relay group, a data collector, a master controller, a first output bus and a second output bus; s2, detecting for the first time: acquiring the voltage of a first battery by a data acquisition unit; s3, detecting again: acquiring the voltage of a second battery by the data acquisition unit; s4, routing inspection: a data collector collects the voltages of the batteries one by one in sequence; and S5, finishing inspection: controlling all the channel switching relays to be switched off by the main controller. According to the method, the positive and negative polarities of the two ends of the single battery can be automatically adjusted, and an operation time sequence cooperation function between the relay switching action and the data collector is provided.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of water electrolysis hydrogen production and hydrogen fuel cell, in particular to a voltage patrol method combining electrolysis hydrogen production and hydrogen fuel cell stack. BACKGROUND

[0002] Hydrogen energy is a kind of secondary energy with abundant sources, green and low carbon, and wide application, is an important part of future national energy system, is an important carrier for green and low carbon transformation of energy terminal, and is a strategic emerging industry and future industry development direction. China's hydrogen energy industry is developing positively, and has initially mastered the main technologies and production processes of hydrogen energy preparation, storage and transportation, hydrogenation, fuel cell and system integration.

[0003] The comprehensive performance index of electrolytic hydrogen production and hydrogen fuel cell can be characterized by its electrical performance, and voltage is the most direct reflection of the performance of electrolytic cell and fuel cell stack. Therefore, it is of great significance to carry out voltage test of the electrical performance of electrolytic hydrogen production and hydrogen fuel cell, which helps to make breakthroughs in the core technologies of electrolytic hydrogen production and hydrogen fuel cell, accelerate the industrialization process of electrolytic hydrogen production and hydrogen fuel cell, and help China's energy low-carbon green transformation and realization of "double carbon" target.

[0004] The existing problems in the evaluation of the electrical performance of the stack are: (1) There is no special metrological standard. According to the relevant standards, the performance evaluation equipment of the test system for the stack (including hydrogen fuel cell and hydrogen production by electrolysis) needs to be checked by the metrological department. In actual work, the CVM of the stack is integrated in the monitoring and control system of the stack and cannot be detached for inspection, which increases the difficulty of inspection and reduces the reliability of inspection. At present, there is no special "metrological standard" on the market that can be directly used for the metrological inspection of the CVM. Therefore, a special device needs to be developed to solve this problem. (2) The existing equipment indicators are not high enough. The technical indicators of the CVM require a voltage measurement error of ±5mV. As a metrological standard, the indicators need to be two levels higher than the measured object, which should reach ±1mV or ±0.1% (even ±0.05% or higher). (3) The existing CVM has a coordination problem between switch operation and data acquisition. There are two schemes for the CVM: the first one is to use a multi-channel synchronous data acquisition device to record the voltage parameters of multiple single cells of the stack in real time. However, the number of synchronous channels of the multi-channel synchronous data acquisition device cannot be too large (that is, the number of channels is limited, and the number of channels on the market is thirty or more). The use of the number of expansion collectors cannot well adapt to various sizes of the stack, and the cost of equipment investment is higher and the precision is lower. The second way is to use a high-precision single collector combined with a multi-channel scanning switch to expand the number of acquisition channels, which can better adapt to various sizes of the stack. However, the second technical scheme has a coordination problem between the two steps of "switch operation" and "data acquisition", which needs to be solved urgently.

[0005] I. Chinese utility model patent (CN201859204U) proposes a multi-channel switch simulation method. The patent uses two multi-channel analog switches with a total of thirty-two channels, but only collects fifteen single cells, with a low utilization rate. Secondly, the COM common end of the midpoint of the fifteen single cells will have a potential accumulation. The patent uses a low number of AD bits, which can only be used for monitoring of the stack and cannot be used as a metrological standard.

[0006] II. Chinese invention patent (CN102288813B) proposes a fuel cell stack single cell voltage inspection system that can detect positive and negative voltages. The system can measure positive and negative signals, but the method of grounding the rear end of the battery gating will cause potential accumulation. In addition, the gating switching process of this method is complex and not suitable for complex fuel cell stack systems. Chinese utility model patent (CN212517270U) provides a single cell inspection system for fuel cells. The isolation scheme proposed can solve the problem of contact potential accumulation of the battery stack, but it does not solve the problem of contact potential of single cells.

[0007] III. Chinese invention patent (CN108761350B) proposes a fuel cell stack single cell voltage patrol system with start-stop balanced control, which selects each single cell in turn through an optical coupling gating circuit, and corrects the positive and negative relationship of the voltage signal by an odd-even conversion module. However, the single cell voltage patrol system proposed in the patent does not have the function of synchronous trigger pulse output, and it does not mention how to cooperate with the data collector after the switch gating. Since there is a transition time from switch gating to signal establishment, in order to correctly collect the voltage across the single cell, the transition time cannot be ignored. If the data collection work is earlier than the signal establishment completion time, the collection system will collect the transition state data, which will lead to unreliable or incorrect collection data.

[0008] In summary, there is an urgent need in the technical field to develop a voltage patrol method for fusion of electrolytic hydrogen production and hydrogen fuel cell stack, which can overcome the defects of the prior art described above SUMMARY

[0009] The technical problem to be solved by the present application is to provide a voltage patrol method for fusion of electrolytic hydrogen production and hydrogen fuel cell stack.

[0010] The technical solution of the present application is as follows: a voltage patrol method for fusion of electrolytic hydrogen production and hydrogen fuel cell stack, comprising the following steps:

[0011] S1, setting a synchronous patrol switch, including: a stack, a scanning relay group, a polarity relay group, a data collector, a main controller, a first output bus, and a second output bus;

[0012] The stack includes N series-connected batteries, the negative poles of the N batteries are respectively connected with the left ends of N lead wires, the positive pole of the Nth battery is connected with the left end of the N+1th lead wire, and N is an integer greater than 2;

[0013] The scanning relay group includes N+1 channel switching relays, the right ends of the N lead wires are respectively connected with the static contacts of the N channel switching relays, the right end of the N+1th lead wire is connected with the static contact of the N+1th channel switching relay, among the N+1 channel switching relays, the moving contacts of the odd-numbered channel switching relays are connected with the first output bus, and the moving contacts of the even-numbered channel switching relays are connected with the second output bus;

[0014] The polar relay group includes a first polarity switching relay and a second polarity switching relay, a first static contact of the first polarity switching relay is connected with the first output bus, a second static contact of the first polarity switching relay is connected with the second output bus, a moving contact of the first polarity switching relay is connected with a first collection end of the data collector, a first static contact of the second polarity switching relay is connected with the first output bus, a second static contact of the second polarity switching relay is connected with the second output bus, and a moving contact of the second polarity switching relay is connected with a second collection end of the data collector;

[0015] The master controller has N+1 gating channel signal pins, which are respectively connected with coils of N+1 channel switching relays, the master controller further has a first polarity selection signal pin and a second polarity selection signal pin, the first polarity selection signal pin is connected with the coil of the first polarity switching relay, the second polarity selection signal pin is connected with the coil of the second polarity switching relay, and the master controller further has a synchronous collection signal pin, which is connected with a trigger end of the data collector;

[0016] S2, first detection: the master controller controls the first channel switching relay and the second channel switching relay to be turned on, and controls the rest of the channel switching relays to be turned off;

[0017] The master controller further controls the first polarity switching relay to make the first output bus and the first collection end of the data collector be turned on, and controls the second polarity switching relay to make the second output bus and the second collection end of the data collector be turned on;

[0018] After a delay time of relay switching completion, the master controller sends a synchronous collection signal to the trigger end of the data collector, and the data collector collects the voltage of the first battery;

[0019] S3, second detection: the master controller controls the second channel switching relay and the third channel switching relay to be turned on, and controls the rest of the channel switching relays to be turned off;

[0020] The master controller further controls the first polarity switching relay to make the second output bus and the first collection end of the data collector be turned on, and controls the second polarity switching relay to make the first output bus and the second collection end of the data collector be turned on;

[0021] After a delay time of relay switching completion, the master controller sends a synchronous collection signal to the trigger end of the data collector, and the data collector collects the voltage of the second battery;

[0022] S4, inspection: the data collector collects the voltage of the battery in sequence;

[0023] Before collecting the voltage of the first odd battery, the main controller controls the channel switching relays on both sides of the first odd battery to be on, and the rest of the channel switching relays to be off;

[0024] The main controller also controls the first polarity switching relay to make the first output bus connect with the first collection end of the data collector, and controls the second polarity switching relay to make the second output bus connect with the second collection end of the data collector;

[0025] After a delay time of the completion of the relay switching, the main controller sends a synchronous collection signal to the trigger end of the data collector, and the data collector collects the voltage of the first odd battery;

[0026] Before collecting the voltage of the first even battery, the main controller controls the channel switching relays on both sides of the first even battery to be on, and the rest of the channel switching relays to be off;

[0027] The main controller also controls the first polarity switching relay to make the second output bus connect with the first collection end of the data collector, and controls the second polarity switching relay to make the first output bus connect with the second collection end of the data collector;

[0028] After a delay time of the completion of the relay switching, the main controller sends a synchronous collection signal to the trigger end of the data collector, and the data collector collects the voltage of the first even battery.

[0029] S5, ending the inspection: the main controller controls all the channel switching relays to be off.

[0030] Further, in the S1, further comprising: a relay driving module, the N+1 gating channel signal pins are respectively connected with the coils of the N+1 channel switching relays through N+1 relay driving modules.

[0031] Further, in the S1, further comprising: a state monitoring module, the N+1 relay driving modules are also respectively connected with N+1 state monitoring modules.

[0032] Further, in the S1, further comprising: a synchronous pulse output module, the synchronous collection signal pin is connected with the trigger end of the data collector through the synchronous pulse output module.

[0033] Further, in the S1, further comprising: a first cascade port, a second cascade port, a communication module and an upper computer, the first cascade port and the second cascade port are respectively connected with the first cascade signal pin and the second cascade signal pin of the main controller, and the upper computer is connected with the main controller through the communication module.

[0034] The synchronous inspection switch has multiple and is arranged in cascade to form a synchronous inspection switch array, the first cascade port of the synchronous inspection switch of the current stage is connected with the second cascade port of the synchronous inspection switch of the previous stage, and the second cascade port of the synchronous inspection switch of the current stage is connected with the first cascade port of the synchronous inspection switch of the next stage.

[0035] Further, in the S1, a power module, a key module and a display module are further included, the power module is connected with the power signal pin of the master controller, the key module is connected with the key signal pin of the master controller, and the display module is connected with the display signal pin of the master controller.

[0036] Further, in the S1, a self-calibration module is further included, the self-calibration module includes N series resistors, one single gain precision buffer is connected in series at the two ends of each resistor, the N series resistors are connected with a power supply, and the left end of the Nth lead wire is connected with the Nth single gain precision buffer.

[0037] Further, the power supply is a programmable signal source.

[0038] Further, before the S2, the following is further included:

[0039] S2-1, self-calibration: the N lead wires are disconnected with the N series batteries, and the left ends of the N lead wires are connected with N single gain precision buffers respectively;

[0040] The power supply outputs a specified electrical signal to the N series resistors, and the synchronous inspection switch further inspects the N series resistors.

[0041] Compared with the background art, the present application has the following beneficial effects or advantages:

[0042] (1) The data collector used by the synchronous inspection switch is a high-speed and high-precision digital sampling voltmeter (similar to a high-precision ADC converter), and actual test verification shows that when the sampling rate meeting the inspection speed requirement is used, the relative error of digital sampling is better than ±0.01%, which is better than ±0.1% (±5mV) of the prior art.

[0043] (2) The scanning relay group and the polarity relay group form a switch scanning module, which can realize the automatic adjustment of the positive and negative polarities of the two ends of a single battery. The prior art can realize the automatic adjustment of the positive and negative polarities between single cells, and when used as a comparison measurement metering standard, the contact potential introduced between the switch and the connecting line cannot be ignored, and the contact potential needs to be eliminated when a single cell is measured, so the switch needs to be able to realize the positive and negative measurement of a single battery.

[0044] (3) Provide the operation timing coordination between the switch action and the data collection to ensure the accuracy and safety of the stack voltage measurement.

[0045] (4) Increase the self-calibration module function to provide the self-calibration function, which can provide the scanning system cycle calibration, in-use inspection and application correction functions; combine the standard dynamic signal to verify the dynamic measurement ability of the scanning system. BRIEF DESCRIPTION OF DRAWINGS

[0046] The application will be further described below with reference to the accompanying drawings and embodiments.

[0047] Figure 1 is the structural diagram of the twenty-four-way synchronous inspection switch unit in the application.

[0048] Figure 2 is the structural diagram of the twenty-four-way synchronous inspection switch array in the application.

[0049] Figure 3 is the structural diagram of the synchronous inspection switch in the application.

[0050] Figure 4 is the self-calibration wiring diagram of the synchronous inspection switch in the application.

[0051] Figure 5 is the operation timing diagram of the synchronous inspection switch in the application.

[0052] Figure 6 is the structural diagram of the master controller in the application.

[0053] Figure 7 is the structural diagram of the power module in the application.

[0054] Figure 8 is the structural diagram of the communication module in the application.

[0055] Figure 9 is the structural diagram of the switch scanning module in the application.

[0056] Figure 10 is the structural diagram of the relay driving module in the application.

[0057] Figure 11 is the structural diagram of the state monitoring module in the application.

[0058] Figure 12 is the structural diagram of the synchronous pulse output module in the application. DETAILED DESCRIPTION

[0059] Please refer to Figures 1 to 12 the preferred embodiment of the application.

[0060] A kind of fusion electrolytic hydrogen production and voltage patrol method of hydrogen fuel cell stack, comprising the following steps:

[0061] S1, set up synchronous patrol switch, including: stack, scanning relay group, polarity relay group, data collector, main controller, first output bus, second output bus;

[0062] The stack includes N batteries in series, the negative pole of N batteries is connected with the left end of N lead respectively, the negative pole of N battery is connected with the left end of N lead, the positive pole of N battery is connected with the left end of N+1 lead, N is integer greater than two;

[0063] The scanning relay group includes N+1 channel switching relays, the right end of N lead is connected with the static contact of N channel switching relays respectively, the right end of N lead is connected with the static contact of N channel switching relays, the right end of N+1 lead is connected with the static contact of N+1 channel switching relays, among the N+1 channel switching relays, the moving contact of odd ordering channel switching relay is connected with the first output bus, the moving contact of even ordering channel switching relay is connected with the second output bus;

[0064] The polarity relay group includes first polarity switching relay and second polarity switching relay, the first static contact of the first polarity switching relay is connected with the first output bus, the second static contact of the first polarity switching relay is connected with the second output bus, the moving contact of the first polarity switching relay is connected with the first acquisition end of the data collector, the first static contact of the second polarity switching relay is connected with the first output bus, the second static contact of the second polarity switching relay is connected with the second output bus, the moving contact of the second polarity switching relay is connected with the second acquisition end of the data collector;

[0065] The main controller has N+1 gate signal pins, N+1 gate signal pins are connected with the coil of N+1 channel switching relays respectively, N+1 gate signal pins are connected with the coil of N+1 channel switching relays, the main controller also has first polarity signal pin and second polarity signal pin, the first polarity signal pin is connected with the coil of the first polarity switching relay, the second polarity signal pin is connected with the coil of the second polarity switching relay, the main controller also has synchronous acquisition signal pin, the synchronous acquisition signal pin is connected with the trigger end of the data collector;

[0066] S2, first detection: the main controller controls first channel switching relay and second channel switching relay conduction, and the rest channel switching relay is disconnected;

[0067] The main controller also controls the first polarity switching relay to make the first output bus conductive with the first collection end of the data collector, and controls the second polarity switching relay to make the second output bus conductive with the second collection end of the data collector;

[0068] After a delay time of relay switching completion, the main controller sends a synchronous collection signal to the trigger end of the data collector, and the data collector collects the voltage of the first battery;

[0069] S3, detection again: the main controller controls the second channel switching relay and the third channel switching relay to be conductive, and controls the rest of the channel switching relays to be disconnected;

[0070] The main controller also controls the first polarity switching relay to make the second output bus conductive with the first collection end of the data collector, and controls the second polarity switching relay to make the first output bus conductive with the second collection end of the data collector;

[0071] After a delay time of relay switching completion, the main controller sends a synchronous collection signal to the trigger end of the data collector, and the data collector collects the voltage of the second battery;

[0072] S4, inspection: the data collector collects the voltage of the battery in sequence;

[0073] Before collecting the voltage of the first odd battery, the main controller controls the channel switching relays located on both sides of the first odd battery to be conductive, and controls the rest of the channel switching relays to be disconnected;

[0074] The main controller also controls the first polarity switching relay to make the first output bus conductive with the first collection end of the data collector, and controls the second polarity switching relay to make the second output bus conductive with the second collection end of the data collector;

[0075] After a delay time of relay switching completion, the main controller sends a synchronous collection signal to the trigger end of the data collector, and the data collector collects the voltage of the first odd battery;

[0076] Before collecting the voltage of the first even battery, the main controller controls the channel switching relays located on both sides of the first even battery to be conductive, and controls the rest of the channel switching relays to be disconnected;

[0077] The main controller also controls the first polarity switching relay to make the second output bus conductive with the first collection end of the data collector, and controls the second polarity switching relay to make the first output bus conductive with the second collection end of the data collector;

[0078] The master sends a synchronous acquisition signal to the trigger end of the data collector after a delay time of relay switching is completed, and the data collector collects the voltage of the even-numbered battery.

[0079] S5, ending the inspection: the master controls all channel switching relays to be disconnected.

[0080] In the present application, the master sends a selected channel signal to the scanning relay group, so that the adjacent two channel switching relays are sequentially turned on and off for inspection. The master also sends a selected polarity signal to the polarity relay group, so that the first polarity switching relay and the second polarity switching relay are polarity reversed each time, thereby keeping the first acquisition end of the data collector connected to the positive pole of a single battery and the second acquisition end connected to the negative pole of a single battery, and sequentially selecting the battery of the stack for voltage detection. After a specified delay time, i.e. a delay time of relay switching completion, the master sends a signal to trigger the data collector to perform acquisition work, ensuring that the acquisition detection is performed when the contacts of the channel switching relay are closed stably, thereby improving the accuracy of voltage detection.

[0081] In combination Figure 3 , Figure 3 is a structural schematic diagram of a synchronous inspection switch in the present application. N series-connected batteries are C1 to Cn; N+1 channel switching relays are S1 to Sn+1; the first polarity switching relay is K1; the second polarity switching relay is K2; the first output bus is P1; the second output bus is P2; the first acquisition end of the data collector is H; and the second acquisition end of the data collector is L.

[0082] For example, the electric pile includes twenty-four batteries in series, the negative electrode of the first battery is connected with the left end of the first lead wire, the negative electrode of the twenty-fourth battery is connected with the left end of the twenty-fourth lead wire, and the positive electrode of the twenty-fourth battery is connected with the left end of the twenty-fifth lead wire; the channel switching relay has twenty-five, wherein the moving contact of the odd-numbered channel switching relay of the first, third, fifth to twenty-fifth is connected with the first output bus, and the moving contact of the even-numbered channel switching relay of the second, fourth, sixth to twenty-fourth is connected with the second output bus. The main control unit has twenty-five gating channel signal pins. When the first channel switching relay and the second channel switching relay select the first battery, the first polarity switching relay selects the first output bus, and the second polarity switching relay selects the second output bus; when the second channel switching relay and the third channel switching relay select the second battery, the first polarity switching relay selects the second output bus, and the second polarity switching relay selects the first output bus; when the third channel switching relay and the fourth channel switching relay select the third battery, the first polarity switching relay selects the first output bus, and the second polarity switching relay selects the second output bus; when the fourth channel switching relay and the fifth channel switching relay select the fourth battery, the first polarity switching relay selects the second output bus, and the second polarity switching relay selects the first output bus; and so on, to complete the patrol and polarity reversal.

[0083] Further, in combination with Figure 1 , Figure 1 is the structural diagram of the twenty-four-way synchronous patrol switch unit in the application. In the S1, further comprising: a relay driving module, the N+1 gating channel signal pins are respectively connected with the coils of the N+1 channel switching relays through N+1 relay driving modules. The N+1 gating channel signal pin is connected with the coil of the N+1 channel switching relay through the N+1 relay driving module.

[0084] From the description, it can be known that the relay driving module is provided to provide sufficient electrical signals and more stably make the channel switching relay perform switching action.

[0085] Further, in combination with Figure 1 , in the S1, further comprising: a state monitoring module, the N+1 relay driving modules are further respectively connected with N+1 state monitoring modules. The N+1 relay driving module is further connected with the N+1 state monitoring module.

[0086] From the description, it can be known that the state monitoring module can more clearly understand whether the corresponding channel switching relay is in the on state or in the off state.

[0087] Further, in combination with Figure 1In the S1, further comprising: a synchronization pulse output module, the synchronization acquisition signal pin and the trigger end of the data collector are connected through the synchronization pulse output module.

[0088] From the description, the synchronization pulse output module is used for strengthening the synchronization acquisition signal sent by the host controller, and helps to stably trigger the acquisition work of the data collector.

[0089] Further, in combination with Figure 1 In the S1, further comprising: a first cascade port, a second cascade port, a communication module and an upper computer, the first cascade port and the second cascade port are connected with the first cascade signal pin and the second cascade signal pin of the host controller respectively, and the upper computer is connected with the host controller through the communication module.

[0090] In combination with Figure 2 , Figure 2 It is the structure block diagram of the twenty-four-way synchronization inspection switch array in the application. The synchronization inspection switch is multiple and is arranged in cascade to form a synchronization inspection switch array, the first cascade port of the synchronization inspection switch of the present stage is connected with the second cascade port of the synchronization inspection switch of the last stage, and the second cascade port of the synchronization inspection switch of the present stage is connected with the first cascade port of the synchronization inspection switch of the next stage.

[0091] The first cascade port is the cascade port I in Figure 1 and Figure 2 The second cascade port is the cascade port II in Figure 1 and Figure 2 .

[0092] From the description, the synchronization inspection switch of the application has a cascade function, multiple synchronization inspection switches are cascaded in order, and more battery stacks in series can be inspected. The upper computer controls the orderly work of the synchronization inspection switches of all stages through the communication module.

[0093] Further, in combination with Figure 1 In the S1, further comprising: a power module, a key module and a display module, the power module is connected with the power signal pin of the host controller, the key module is connected with the key signal pin of the host controller, and the display module is connected with the display signal pin of the host controller.

[0094] From the description, the power module supplies power, the key module is used for inputting setting parameters to the host controller, and the display module is used for outputting operation results to the outside by the host controller, so that the working personnel can know the state of the present synchronization inspection switch.

[0095] Further, in combination with Figure 4 , Figure 4Is the self-calibration wiring schematic diagram of the synchronous patrol switch in the application. In the S1, further comprising: a self-calibration module, the self-calibration module comprises N series resistors, each resistor is connected with a single gain precision buffer in series at both ends, the N series resistors are connected with a power supply, and the left end of the Nth lead is connected with the Nth single gain precision buffer.

[0096] From the description, the self-calibration module simulates the battery stack, which is used for calibrating the running state of the synchronous patrol switch, helps to debug the synchronous patrol switch, and improves the accuracy of the subsequent actual battery detection.

[0097] The N series batteries are V1 to Vn in the Figure 4 The N single gain precision buffers are U1 to Un in the Figure 4

[0098] Further, the power supply is a programmable signal source.

[0099] From the description, the programmable signal source simulates single-cell voltage signals with various change characteristics, which is used for verifying the measurement capability of the scanning measurement system under different battery running conditions.

[0100] Further, before the S2, further comprising:

[0101] S2-1, self-calibration: the N leads are disconnected with the N series batteries, and the left ends of the N leads are connected with the N single gain precision buffers respectively;

[0102] The power supply outputs a specified electrical signal to the N series resistors, and the synchronous patrol switch patrols the N series resistors again.

[0103] From the description, after the voltage patrol of the battery, the self-calibration of the synchronous patrol switch is performed first, which ensures the functional stability of the synchronous patrol switch, and helps to improve the reliability of the battery patrol result.

[0104] In order to better understand the above technical solutions, the following will be described in detail.

[0105] ​The present application aims to provide a voltage inspection method for fusing electrolytic hydrogen production and hydrogen fuel cell stack, for constructing a measurement standard device, to solve the following problems in the prior art: (1) There is no special measurement standard device for evaluating the electrical performance of the stack, and the precision is not high enough. (2) As the voltage amplitude of each single cell is not high, the contact potential introduced between the switch and the connecting wire cannot be ignored when using the measurement standard device for comparison measurement. Therefore, the switch should be able to realize the positive and negative measurement of a single cell. (3) Due to the uncertainty of the field environment, a self-calibration module is provided to verify the measurement capability of the scanning system under different stack operating conditions. (4) There is a transition time from the switch gating to the signal establishment. To correctly collect the voltage of the single cell, the voltage inspection system needs to have a synchronous trigger pulse output function to complete the timing coordination between the scanning switch unit and the data acquisition system.

[0106] The synchronous inspection switch can be used for voltage inspection of various types of stacks (such as fuel cell stacks, water electrolytic hydrogen production electrolytic cell stacks, or single cells of battery modules (hereinafter referred to as "single cells"). The synchronous inspection switch is designed in a modular form as a synchronous inspection switch unit, each unit can scan twenty-four single cells, as shown in Figure 1 The structure of the twenty-four-way synchronous inspection switch unit in the present application is composed of an MCU main controller, a power module, a communication module, a switch scanning module, a relay driving and state monitoring module, a synchronous pulse output module, a self-calibration module, and a peripheral module (keys, display). The present patent uses a high-speed and high-precision digital sampling voltmeter (similar to a high-precision ADC converter), and the units are connected in cascade to expand the number of scanning channels to adapt to different sizes of stacks. In theory, it can be expanded indefinitely, as shown in Figure 2 .

[0107] The synchronous inspection switch has the following three characteristics:

[0108] (1) Scanning switch group (S1, S2... S25; K1, K2)

[0109] The switch scanning module is composed of twenty-five channel switching relays and two polarity switching relays. The twenty-five channel switching relays are used for channel switching of twenty-four single cells, each single cell is connected to two channel switching relays, and each channel switching relay is connected to the first output bus P1 and the second output bus P2 in order according to the order of the connected single cell. The two polarity switching relays are used for polarity reversal (as shown in Figure 3 ). Through the design of two-level switch structure, the number of measurement leads can be reduced from 2n to n+1, and the switch scanning module can also realize polarity adjustment between channels and the channel itself.

[0110] The master controller sends commands according to the working conditions, and the commands are controlled by two control codes, one is "select channel", and the other is "select polarity". When the channel sequence is inspected, the polarity of the first output bus P1 alternately presents positive and negative, and the polarity of the second output bus P2 alternately presents negative and positive, and the polarity of the first output bus P1 and the second output bus P2 can be changed through the first polarity switching relay K1 and the second polarity switching relay K2, so that the output polarity of the final bus remains unchanged. On the other hand, the voltage amplitude of a single cell is generally low, at this time, the influence of the comprehensive parasitic potential introduced by the connection between the measuring lead, the relay, the measuring meter and other components due to temperature change cannot be ignored, the contact thermal electromotive force is measured by the "polarity reversal method", and the measurement result is corrected to deduct the cumulative problem of contact potential when multiple single cells are connected in series.

[0111] (2) Self-calibration module

[0112] The self-calibration module is composed of twenty-four precise alloy foil resistors with the same resistance value to form a twenty-four-way "1:1....:1" resistance dividing network, and one single-gain precision buffer is connected in series at both ends of each resistor, so that the differential voltage Vi (i=1, 2,..., 24) at both ends of each resistor is equal to the input voltage Ui (i=1, 2,..., 24) of the switch scanning module, that is, the twenty-four single cell voltages (which can be regarded as standard voltages here) are simulated, and the output impedance of the dividing network is transformed, thereby isolating the influence of the measurement loop on the load side. Combined with Figure 4 , the self-calibration module can be externally connected to a programmable signal source as a calibration signal input, simulating single cell voltage signals with various changing characteristics, for verifying the measurement capability of the scanning measurement system under different stack operating conditions.

[0113] (3) Synchronous signal output module

[0114] The patent adopts a high-precision single collector combined with a multi-channel switch scanning structure, which expands the number of collection channels by increasing the number of multi-channel switch scanning, and can better adapt to various sizes of stacks. However, when the multi-way switch is used to inspect the single cell voltage of the stack, one detail that is easily overlooked is the operation coordination of the channel switch and the rear-end data collector. The transition time from receiving the closing command to fully closing the switch is defined as the "signal establishment time", and after the delay of the signal establishment time, the switch generates a synchronous pulse output signal as the trigger signal for the data collector to start sampling. In addition, in order to ensure the safety of the scanning measurement, only one single cell is allowed to be connected at any time, and the "first disconnect then connect" principle is implemented, and after the data collector completes the collection and reading, it also gives a "measurement complete" state identifier to inform the switch to perform the disconnection operation.

[0115] As shown in Figure 5 ,Figure 5 is the schematic diagram of the timing of the synchronous inspection switch operation in the invention. When the upper computer sends the switch closing command, due to the action switching time of the relay, there is a delay t1 between the time when the switch is connected and the output TTL pulse. When the timing sampling mode is adopted, the first sampling will be performed after a trigger delay time t2 after the rising edge (or falling edge, depending on the polarity setting of the trigger edge) of the TTL pulse. The n samples of each channel are performed at equal time intervals, and the total sampling time should be included in the connection time of each channel. t1 is the action time of the relay, in order to ensure that each sampling is only for one channel, the sampling of the next channel should be performed after the previous channel is disconnected, so the action time of the relay should be considered as 2t1, about 8ms. The trigger delay time t2 is related to the set integration time, when the set integration time is 20ms (equivalent to NPLC=1), the trigger delay is 160μs. If the number of channel sampling samples is n, the time for completing one channel sampling is n times the integration period. To successfully complete the independent and complete sampling of each channel, the operation timing of each part should be fully analyzed, and the sampling process of each channel should be included in the "connection time" of the switch and the "time interval" of the sampling, and the characteristics of the measured signal should be considered.

[0116] The present patent has the following four improvements compared with the existing technology:

[0117] (1) The data collector used in the synchronous inspection switch is a high-speed and high-precision digital sampling voltmeter (similar to a high-precision ADC converter), which has been tested and verified that when the sampling rate meets the inspection speed requirement, the relative error of digital sampling is better than ±0.01%, which is better than ±0.1% (±5mV) of the existing technology.

[0118] (2) The scanning relay group and the polarity relay group form a switch scanning module, which can automatically adjust the positive and negative polarity of the single battery. The existing technology can automatically adjust the positive and negative polarity between each single cell, and when used as a comparison measurement standard, the contact potential introduced between the switch and the connecting line cannot be ignored, and the contact potential needs to be eliminated when measuring a single cell, so the switch should be able to realize the positive and negative measurement of a single battery.

[0119] (3) The operation timing between switch action and data collection is coordinated to ensure the accuracy and safety of the stack voltage measurement.

[0120] (4) The self-calibration module function is added to provide self-calibration function, which can provide periodic calibration of the scanning system, in-service inspection, and in-application correction function; combined with standard dynamic signals, the dynamic measurement capability of the scanning system is verified.

[0121] The synchronous inspection switch of the present application can be used for voltage inspection of various types of stacks (such as fuel cell stacks, water electrolysis hydrogen production electrolytic cell stacks or single cells (hereinafter referred to as "single cells") of a battery module). The synchronous inspection switch is designed in a modular manner into a unit, each unit can scan twenty-four single cells, as shown in the figure, which is composed of a master controller, a power module, a communication module, a switch scanning module, a relay drive and state monitoring module, a synchronous pulse output module, a self-calibration module and peripheral modules (keys, display) and the like. Figure 1

[0122] In combination with Figure 6 ; master controller: the master controller (MCU) uses STM32F103RBT6, based on ARM Cortex-M3 core, the highest working frequency is 72MHz, providing 90DMIPS (million instructions per second) processing power, supporting single-cycle multiplication and hardware division operation, using 32-bit RISC architecture, the instruction set is simple and efficient, suitable for real-time control and complex algorithm processing.

[0123] In combination with Figure 7 ; power module: input power voltage conversion circuit, realizing (9-24)V to 5V, while supporting USB input, used for providing working power and control voltage for single-chip microcomputer and relay. The power module also includes TPS5430 power conversion chip, using fixed frequency (500kHz) control mode, supporting high-precision output regulation. Input voltage range: 5.5V to 36V, output voltage adjustable range 1.221V to 32V, precision up to ±1.5%, conversion efficiency up to 95%, continuous output current up to 3A, meeting the demand of high load, which is responsible for power supply for the relay drive module.

[0124] In combination with Figure 8 ​; Communication module: The communication between the synchronous inspection switch and the host computer is based on serial port, and FT232R serial conversion chip is adopted. FT232R converts USB interface into standard RS-232 / RS-422 / RS-485 serial communication interface through the built-in USB protocol engine and UART controller, realizes the interaction between PC and serial port device (scanning switch), supports asynchronous communication mode (character transmission) and synchronous FIFO mode (high-speed data block transmission), is compatible with RS-232, RS-422, RS-485 and other serial protocols, supports baud rate up to 3 Mbps, can be directly connected to the UART pin (0V / 3.3V or 5V logic) of the host controller to generate TTL level. In the switch scanning module, the USB1 port is responsible for the communication between the host computer and the switch scanning module. The communication part of the switch scanning module also includes the cascade between different modules, the USB2 port of the latter module is connected with the USB3 port of the former module through two USB-TYPE-C interface terminals, which is used for providing the communication between the single-chip microcomputer of the cascaded module and the host computer and power supply

[0125] In combination Figure 9 ; Switch scanning module: The switch scanning module includes input and output parts, both of which adopt TX2-5V electromagnetic relays, the input part adopts twenty-five scanning relay groups, and the output part adopts two polarity relay groups. TX2-5V works based on electromagnetic induction principle, generates a magnetic field through coil power-on, attracts armature to drive the contact to close or open, and realizes the on-off control of the circuit.

[0126] In combination Figure 10 And Figure 11 ; Relay driving and state monitoring module: The scanning relay group adopts three ULN2803A chips for relay driving and state monitoring, and the state monitoring of the relay is indicated by an LED. The polarity conversion relay group adopts two ULN2001D chips, the input end is directly connected with the GPIO pin of the MCU, since the chip is built-in 2.7kΩ base resistance and 4.7kΩ pull-down resistance, it can be directly connected with TTL / CMOS logic circuit, the collector output end (such as 1C, 2C, 3C) of each Darlington transistor is connected with one end of the relay coil, and the other end of the coil is connected with the load power supply. The open-collector output characteristic of ULN2001D can directly drive the conduction and turn-off of the relay coil, and the state monitoring of the relay is also indicated by an LED.

[0127] In combination Figure 12 ; Synchronous pulse output module: Model TLP521 is a controllable optocoupler device, which realizes the electrical isolation between the input end and the output end through the coupling of gallium arsenide infrared light emitting diode (LED) and photosensitive triode, and completes the conversion of electrical signal to optical signal and back to electrical signal.

[0128] Self-calibration module: the self-calibration module is composed of twenty-four precise alloy foil resistors with same resistance value, which forms a twenty-four-way "1:1....:1" resistance dividing network. Two ends of each resistance are connected with a single gain precision buffer respectively, which provides self-calibration function, provides periodic calibration for scanning system, check in use, and correction in application; combined with standard dynamic signal, verifies dynamic measurement capability of scanning system.

[0129] Although the specific embodiments of the present application have been described above, it is understood by those skilled in the art that the specific embodiments described are only illustrative and are not intended to limit the scope of the present application, and equivalent modifications and variations made by those skilled in the art in accordance with the spirit of the present application should be covered within the scope of the claims of the present application.

Claims

1. A voltage monitoring method integrating electrolytic hydrogen production and hydrogen fuel cell stacks, characterized in that, Includes the following steps: S1. Set up a synchronous inspection switch, including: fuel cell stack, scanning relay group, polarity relay group, data acquisition unit, main controller, first output bus, and second output bus; The fuel cell stack includes N batteries connected in series. The negative terminals of the N batteries are connected to the left ends of the N leads respectively, and the positive terminal of the Nth battery is connected to the left end of the (N+1)th lead. N is an integer greater than two. The scanning relay group includes N+1 channel switching relays. The right ends of the N leads are respectively connected to the stationary contacts of the N channel switching relays. The right end of the N+1th lead is connected to the stationary contact of the N+1th channel switching relay. Among the N+1 channel switching relays, the moving contacts of the odd-numbered channel switching relays are connected to the first output bus, and the moving contacts of the even-numbered channel switching relays are connected to the second output bus. The polarity relay group includes a first polarity switching relay and a second polarity switching relay. The first stationary contact of the first polarity switching relay is connected to the first output bus, the second stationary contact of the first polarity switching relay is connected to the second output bus, and the moving contact of the first polarity switching relay is connected to the first acquisition terminal of the data acquisition device. The first stationary contact of the second polarity switching relay is connected to the first output bus, the second stationary contact of the second polarity switching relay is connected to the second output bus, and the moving contact of the second polarity switching relay is connected to the second acquisition terminal of the data acquisition device. The main controller has N+1 channel selection signal pins, which are respectively connected to the coils of N+1 channel switching relays. The main controller also has a first polarity selection signal pin and a second polarity selection signal pin. The first polarity selection signal pin is connected to the coil of the first polarity switching relay, and the second polarity selection signal pin is connected to the coil of the second polarity switching relay. The main controller also has a synchronous acquisition signal pin, which is connected to the trigger terminal of the data acquisition unit. S2. Initial detection: The main controller turns on the first and second channel switching relays, and turns off the remaining channel switching relays; The main controller also controls the first polarity switching relay to connect the first output bus to the first acquisition terminal of the data acquisition unit, and controls the second polarity switching relay to connect the second output bus to the second acquisition terminal of the data acquisition unit. After a delay following the relay switching, the main controller sends a synchronous acquisition signal to the trigger terminal of the data acquisition unit, which then acquires the voltage of the first battery. S3. Re-detection: The main controller controls the second and third channel switching relays to be turned on, while the remaining channel switching relays are turned off. The main controller also controls the first polarity switching relay to connect the second output bus to the first acquisition terminal of the data acquisition unit, and controls the second polarity switching relay to connect the first output bus to the second acquisition terminal of the data acquisition unit. After a delay following the relay switching, the main controller sends a synchronous acquisition signal to the trigger terminal of the data acquisition unit, which then acquires the voltage of the second battery. S4. Inspection: The data acquisition device collects the voltage of each battery sequentially. Before the voltage of the odd-numbered battery is collected, the main controller controls the channel switching relays located on both sides of the odd-numbered battery to be turned on, and the channel switching relays of the other channels to be turned off. The main controller also controls the first polarity switching relay to connect the first output bus to the first acquisition terminal of the data acquisition unit, and controls the second polarity switching relay to connect the second output bus to the second acquisition terminal of the data acquisition unit. After a delay following the relay switching, the main controller sends a synchronous acquisition signal to the trigger terminal of the data acquisition unit, which then acquires the voltage of the odd-numbered battery. Before the voltage of the even-numbered battery is collected, the main controller controls the channel switching relays located on both sides of the even-numbered battery to be turned on, and the channel switching relays of the other batteries to be turned off. The main controller also controls the first polarity switching relay to connect the second output bus to the first acquisition terminal of the data acquisition unit, and controls the second polarity switching relay to connect the first output bus to the second acquisition terminal of the data acquisition unit. After a delay following the relay switching, the main controller sends a synchronous acquisition signal to the trigger terminal of the data acquisition unit, which then acquires the voltage of the even-numbered battery. S5. End of Inspection: The main controller disconnects all channel switching relays.

2. The voltage monitoring method for a hydrogen fuel cell stack integrating electrolysis hydrogen production and hydrogen fuel cell stack according to claim 1, characterized in that, S1 further includes: a relay driving module, wherein the N+1 channel selection signal pins are respectively connected to the coils of the N+1 channel switching relays through the N+1 relay driving module.

3. The voltage monitoring method for a hydrogen fuel cell stack integrating electrolysis hydrogen production and hydrogen fuel cell stack according to claim 1, characterized in that, The S1 also includes a status monitoring module, and the N+1 relay drive modules are respectively connected to the N+1 status monitoring module.

4. The voltage monitoring method for a hydrogen fuel cell stack integrating electrolysis hydrogen production and hydrogen fuel cell stack according to claim 1, characterized in that, S1 further includes a synchronization pulse output module, wherein the synchronization acquisition signal pin is connected to the trigger terminal of the data acquisition device through the synchronization pulse output module.

5. The voltage monitoring method for a hydrogen fuel cell stack integrating electrolytic hydrogen production and hydrogen fuel cell stack according to claim 1, characterized in that, The S1 further includes: a first cascade port, a second cascade port, a communication module, and a host computer. The first cascade port and the second cascade port are respectively connected to the first cascade signal pin and the second cascade signal pin of the main controller. The host computer is connected to the main controller through the communication module. The synchronous inspection switches are multiple and cascaded to form a synchronous inspection switch array. The first cascade port of the synchronous inspection switch in this stage is connected to the second cascade port of the synchronous inspection switch in the previous stage, and the second cascade port of the synchronous inspection switch in this stage is connected to the first cascade port of the synchronous inspection switch in the next stage.

6. The voltage monitoring method for a hydrogen fuel cell stack integrating electrolysis hydrogen production and hydrogen fuel cell stack according to claim 1, characterized in that, The S1 further includes a power module, a button module, and a display module. The power module is connected to the power signal pin of the main controller, the button module is connected to the button signal pin of the main controller, and the display module is connected to the display signal pin of the main controller.

7. The voltage monitoring method for a hydrogen fuel cell stack integrating electrolytic hydrogen production and hydrogen fuel cell stack according to claim 1, characterized in that, S1 also includes a self-calibration module, which comprises N series resistors, each resistor having a single-gain precision buffer connected in series at both ends. The N series resistors are connected to an external power supply, and the left end of the Nth lead is connected to the Nth single-gain precision buffer.

8. The voltage monitoring method for a hydrogen fuel cell stack integrating electrolysis hydrogen production and hydrogen fuel cell stack according to claim 7, characterized in that, The power supply is a programmable signal source.

9. The voltage monitoring method for a hydrogen fuel cell stack integrating electrolytic hydrogen production and hydrogen fuel cell stack according to claim 7, characterized in that, Before S2, it also includes: S2-1, Self-calibration: The N leads are disconnected from the N series-connected batteries, and the left ends of the N leads are respectively connected to N single-gain precision buffers; The power supply outputs a specified electrical signal to the N series-connected resistors, and the synchronous inspection switch then performs an inspection on the N series-connected resistors.

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