Fuel cell stack diagnostic method, device and computer storage medium

Abstract

The present application discloses a fuel cell stack diagnostic method, device and computer storage medium, including: obtaining the current output current of the fuel cell and the current single cell voltage of all single cells in the fuel cell stack; performing first-order linear fitting on the single cell voltage of all single cells to obtain the current value of the preset characteristic parameter of the fitting trend line; searching a preset database according to the current output current to obtain the reference value of the preset characteristic parameter corresponding to the current output current; wherein the preset database stores the reference value of the preset characteristic parameter corresponding to the control of the fuel cell stack to work under different output currents and different preset operating conditions; diagnosing the operating state of the fuel cell stack according to the current value of the preset characteristic parameter and the reference value of the preset characteristic parameter to obtain the diagnostic result. In this way, the operating state of the fuel cell stack can be monitored in real time and accurately, and the operation is simple and low cost.

Description

Technical Field

[0001] The present invention relates to the field of fuel cells, and in particular to a fuel cell stack diagnosis method, device and computer storage medium. Background Art

[0002] In the existing hydrogen fuel cell fault diagnosis and control countermeasures, the judgment conditions for the working state of the fuel cell are relatively simple, and there are problems such as only reflecting the local working state of the fuel cell and the judgment of the overall working state of the stack is too vague. In addition, the traditional fuel cell fault diagnosis strategy only distinguishes between faults such as high single cell voltage, low single cell voltage, and overall low single cell voltage. Among the existing fuel cell stack diagnosis methods, some methods require additional hardware for diagnosis, and the stability of the hardware directly affects the accuracy and real-time performance of the diagnosis, thus having a high dependence on the hardware; other methods rely on big data for diagnosis, and need to process big data.

[0003] Therefore, existing fuel cell stack diagnostic methods have shortcomings such as low accuracy and real-time performance, complex operation and high cost. Summary of the invention

[0004] The object of the present invention is to provide a fuel cell stack diagnostic method, device and computer storage medium, which can monitor the operating status of the fuel cell stack in real time and accurately, and is easy to operate and low in cost.

[0005] To achieve the above object, the technical solution of the present invention is achieved as follows:

[0006] In a first aspect, an embodiment of the present invention provides a fuel cell stack diagnostic method, the method comprising:

[0007] Obtaining the current output current of the fuel cell and the cell voltages of all cells in the fuel cell stack;

[0008] Performing a first-order linear fit on the single cell voltages of all the single cells to obtain current values ​​of preset characteristic parameters of a fitting trend line;

[0009] Searching a preset database according to the current output current to obtain a reference value of the preset characteristic parameter corresponding to the current output current; wherein the preset database stores reference values ​​of preset characteristic parameters corresponding to controlling the fuel cell stack to operate under different output currents and different preset operating conditions;

[0010] The operating state of the fuel cell stack is diagnosed according to the current value of the preset characteristic parameter and the reference value of the preset characteristic parameter to obtain a diagnosis result.

[0011] As one implementation manner, the preset characteristic parameters include a slope and a maximum deviation of the single cell voltages of all single cells from a fitting trend line.

[0012] As one embodiment, the reference value of the slope includes a first reference value and a second reference value of the slope, and the first reference value is less than the second reference value. The operating state of the fuel cell stack is diagnosed according to the current value of the preset characteristic parameter and the reference value of the preset characteristic parameter to obtain a diagnosis result, including:

[0013] When the current value of the slope is greater than the first reference value and less than the second reference value, detecting whether the current value of the maximum deviation satisfies a preset condition;

[0014] If the conditions are met, it is determined that the fuel cell stack is normal;

[0015] If not, it is determined that the fuel cell stack is faulty.

[0016] As one embodiment, the reference value of the maximum deviation includes a third reference value, a fourth reference value and a fifth reference value of the maximum deviation, and the absolute value of the third reference value is greater than the absolute value of the fourth reference value, and the absolute value of the fifth reference value is greater than the absolute value of the third reference value, and the preset condition includes that the absolute value of the current value of the maximum deviation is less than the absolute value of the fourth reference value.

[0017] As one embodiment, the step of diagnosing the operating state of the fuel cell stack according to the current value of the preset characteristic parameter and the reference value of the preset characteristic parameter to obtain a diagnosis result further includes:

[0018] When the current value of the slope is less than the first reference value, it is determined that the fuel cell stack is too dry.

[0019] As one embodiment, the step of diagnosing the operating state of the fuel cell stack according to the current value of the preset characteristic parameter and the reference value of the preset characteristic parameter to obtain a diagnosis result further includes:

[0020] When the current value of the slope is greater than the second reference value, detecting whether the current value of the maximum deviation is greater than the third reference value;

[0021] If the current value of the maximum deviation is greater than the third reference value and less than the fifth reference value, it is determined that the fuel cell stack is short of gas;

[0022] If the current value of the maximum deviation is smaller than the third reference value, it is determined that the fuel cell stack is over-humidified.

[0023] As one implementation manner, before obtaining the current output current of the fuel cell and the current cell voltages of all cells in the fuel cell stack, the method further includes:

[0024] Under the set output current, controlling the fuel cell stack to operate under the preset operating conditions;

[0025] After the average value of the cell voltages of all the cells in the fuel cell stack drops to a preset first threshold value or the cell voltage of at least one cell is less than a preset second threshold value, obtaining a test value of a preset characteristic parameter of a fitting trend line obtained by performing a first-order linear fitting on the cell voltages of all the cells;

[0026] According to the test value of the preset characteristic parameter, a reference value of the preset characteristic parameter when the fuel cell stack operates under the set output current and preset operating conditions is determined.

[0027] As one implementation mode, it also includes:

[0028] When the fuel cell stack is over-humidified, performing at least one of the following operations on the fuel cell stack: reducing humidification, reducing pressure, increasing air flow, increasing temperature; and / or,

[0029] When the fuel cell stack is too dry, performing at least one of the following operations on the fuel cell stack: increasing humidification, increasing pressure, and reducing temperature; and / or,

[0030] When the fuel cell stack is short of gas, at least one of the following operations is performed on the fuel cell stack: increasing the air flow rate and increasing the hydrogen flow rate.

[0031] In a second aspect, an embodiment of the present invention provides a fuel cell stack diagnostic device, which includes a processor and a memory for storing programs; when the program is executed by the processor, the processor implements the fuel cell stack diagnostic method described in the first aspect.

[0032] In a third aspect, an embodiment of the present invention provides a computer storage medium storing a computer program, which, when executed by a processor, implements the fuel cell stack diagnostic method described in the first aspect.

[0033] The fuel cell stack diagnostic method, device and computer storage medium provided by the embodiment of the present invention include: obtaining the current output current of the fuel cell and the current single cell voltage of all single cells in the fuel cell stack; performing first-order linear fitting on the single cell voltage of all single cells to obtain the current value of the preset characteristic parameter of the fitting trend line; searching the preset database according to the current output current to obtain the reference value of the preset characteristic parameter corresponding to the current output current; wherein the preset database stores the reference value of the preset characteristic parameter corresponding to the control of the fuel cell stack to work under different output currents and different preset operating conditions; diagnosing the operating state of the fuel cell stack according to the current value of the preset characteristic parameter and the reference value of the preset characteristic parameter to obtain the diagnostic result. In this way, the current value of the preset characteristic parameter of the fitting trend line is obtained by fitting the real-time single cell voltage of all single cells in the fuel cell stack, and then the operating state of the fuel cell stack is diagnosed based on the current value of the preset characteristic parameter, without the need for additional hardware, and the amount of data to be processed is small, so that the operating state of the fuel cell stack can be monitored in real time and accurately, and the operation is simple and low in cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 A schematic diagram of a fuel cell stack diagnostic method according to an embodiment of the present invention;

[0035] Figure 2 It is a structural schematic diagram of an existing fuel cell control system;

[0036] Figure 3 It is a schematic diagram of the cell voltage distribution and fitting when the fuel cell stack is over-humidified;

[0037] Figure 4 It is a schematic diagram of the single cell voltage distribution and fitting when the fuel cell stack is too dry;

[0038] Figure 5 It is a schematic diagram of the deviation of the cell voltage after fitting when the fuel cell stack is short of gas;

[0039] Figure 6 A schematic diagram of a specific flow chart of a fuel cell stack diagnostic method provided by an embodiment of the present invention;

[0040] Figure 7 A schematic diagram of the structure of a fuel cell stack diagnostic device provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0041] Exemplary embodiments will be described in detail herein, examples of which are shown in the accompanying drawings. When the following description refers to the drawings, the same numbers in different drawings represent the same or similar elements unless otherwise indicated. The implementations described in the following exemplary embodiments do not represent all implementations consistent with the present application. Instead, they are merely examples of devices and methods consistent with some aspects of the present application as detailed in the appended claims.

[0042] It should be noted that, in this article, the terms "include", "comprises" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also includes other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, an element defined by the sentence "includes a ..." does not exclude the existence of other identical elements in the process, method, article or device including the element. In addition, components, features, and elements with the same name in different embodiments of the present application may have the same meaning or different meanings, and their specific meanings need to be determined by their explanation in the specific embodiment or further combined with the context of the specific embodiment.

[0043] It should be understood that, although the terms first, second, third, etc. may be used to describe various information in this article, these information should not be limited to these terms. These terms are only used to distinguish the same type of information from each other. For example, without departing from the scope of this article, the first information may also be referred to as the second information, and similarly, the second information may also be referred to as the first information. Depending on the context, the word "if" as used herein can be interpreted as "at the time of..." or "when..." or "in response to determination". Furthermore, as used in this article, the singular forms "one", "one" and "the" are intended to also include plural forms, unless there is an opposite indication in the context. It should be further understood that the terms "comprising", "including" indicate that there are described features, steps, operations, elements, components, projects, kinds, and / or groups, but do not exclude the existence, occurrence or addition of one or more other features, steps, operations, elements, components, projects, kinds, and / or groups. The terms "or" and "and / or" used herein are interpreted as inclusive, or mean any one or any combination. Thus, “A, B, or C” or “A, B and / or C” means “any of the following: A; B; C; A and B; A and C; B and C; A, B, and C.” An exception to this definition will occur only when a combination of elements, functions, steps, or operations are inherently mutually exclusive in some manner.

[0044] It should be understood that, although the various steps in the flowchart in the embodiment of the present application are displayed in sequence according to the indication of the arrows, these steps are not necessarily performed in sequence according to the order indicated by the arrows. Unless there is a clear explanation in this article, the execution of these steps does not have a strict order restriction, and it can be performed in other orders. Moreover, at least a portion of the steps in the figure may include a plurality of sub-steps or a plurality of stages, and these sub-steps or stages are not necessarily performed at the same time, but can be performed at different times, and their execution order is not necessarily performed in sequence, but can be performed in turn or alternately with other steps or at least a portion of the sub-steps or stages of other steps.

[0045] It should be noted that, in this article, step codes such as S101, S102, etc. are used for the purpose of expressing the corresponding content more clearly and concisely, and do not constitute a substantial limitation on the sequence. When implementing the step, those skilled in the art may execute S102 first and then S101, etc., but these should all be within the scope of protection of this application.

[0046] It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0047] In the subsequent description, the suffixes such as "module", "component" or "unit" used to represent elements are only used to facilitate the description of the present application, and have no specific meanings. Therefore, "module", "component" or "unit" can be used in a mixed manner.

[0048] See also Figure 1 , is a flow chart of a fuel cell stack diagnostic method provided in an embodiment of the present invention. The method can be executed by a fuel cell stack diagnostic device provided in an embodiment of the present invention. The device can be implemented in software and / or hardware, such as a fuel cell controller. In this embodiment, the method is applied to a fuel cell controller as an example. The method includes the following steps:

[0049] Step S101: obtaining the current output current of the fuel cell and the cell voltages of all cells in the fuel cell stack;

[0050] Here, the fuel cell controller obtains the cell voltage of all cells in the current fuel cell stack by receiving the cell voltage of all cells in the fuel cell stack collected and sent by the fuel cell voltage inspection controller in real time or irregularly. It should be noted that the cell voltage includes not only the voltage magnitude parameter but also the corresponding cell identification such as the cell number. In addition, the fuel cell controller can also obtain the current output current of the fuel cell in real time or irregularly.

[0051] Step S102: performing first-order linear fitting on the single cell voltages of all the single cells to obtain current values ​​of preset characteristic parameters of the fitting trend line;

[0052] Here, the preset characteristic parameters are used to characterize the fitting between the cell voltages of all the cells and the fitting trend line, and may specifically include the slope and the maximum deviation between the cell voltages of all the cells and the fitting trend line. The slope can be used to reflect the distribution of the cell voltages of all the cells, such as whether the cell voltage of the cell close to the air inlet end of the fuel cell is greater than or less than the cell voltage of the cell far from the air inlet end of the fuel cell. The maximum deviation is used to reflect the deviation between the cell voltages of all the cells and the fitting trend line.

[0053] Step S103: searching a preset database according to the current output current to obtain a reference value of the preset characteristic parameter corresponding to the current output current; wherein the preset database stores reference values ​​of preset characteristic parameters corresponding to controlling the fuel cell stack to operate under different output currents and different preset operating conditions;

[0054] Here, the fuel cell stack can be pre-controlled to operate under different output currents and different preset operating conditions, and the reference value of the corresponding preset characteristic parameter can be obtained to diagnose the operating state of the fuel cell stack based on the reference value of the preset characteristic parameter. It should be noted that in the correspondence between the reference value of the preset characteristic parameter and different output currents stored in the preset database, the output current can be a single value or an interval value, and the reference value can be a single value or an interval value.

[0055] In one embodiment, before obtaining the current output current of the fuel cell and the current cell voltages of all cells in the fuel cell stack, the method may further include:

[0056] Under the set output current, controlling the fuel cell stack to operate under the preset operating conditions;

[0057] After the average value of the cell voltages of all the cells in the fuel cell stack drops to a preset first threshold value or the cell voltage of at least one cell is less than a preset second threshold value, obtaining a test value of a preset characteristic parameter of a fitting trend line obtained by performing a first-order linear fitting on the cell voltages of all the cells;

[0058] According to the test value of the preset characteristic parameter, the reference value of the preset characteristic parameter when the fuel cell stack operates under the set output current and preset operating conditions is determined. The specific operation process is as follows:

[0059] First, the fuel cell stack is controlled to operate normally for a period of time at a certain output power, so that the water content, temperature, etc. of the fuel cell are within a normal range. At this time, the output current value of the fuel cell stack can be considered to be a set value;

[0060] Next, the output current is kept unchanged, and the operating condition of the fuel cell stack is controlled to become wet or dry. After the average value of the cell voltage of all the cells in the fuel cell stack drops to a preset first threshold value (for example, drops to 70% or 65% of the value before the operating condition of the fuel cell stack is changed), a test value of a preset characteristic parameter of a fitting trend line obtained by performing a first-order linear fitting on the cell voltage of all the cells at this time is obtained;

[0061] Then, the output power of the fuel cell stack is changed so that the output current of the fuel cell stack becomes another set value, the output current is kept unchanged, and the above operation is repeated to obtain different test values ​​of the preset characteristic parameters of the fitting trend line obtained by performing a first-order linear fit on the cell voltages of all the single cells under different output current conditions when the operating conditions of the fuel cell stack are wet and dry respectively.

[0062] Alternatively, the fuel cell stack is first controlled to operate normally at a certain output power for a period of time so that the water content, temperature, etc. of the fuel cell are within a normal range. At this time, the output current value of the fuel cell stack can be considered to be a set value; then, the output current is kept unchanged, and the operating condition of the fuel cell stack is controlled to be gas shortage. After the cell voltage of any single cell in the fuel cell stack drops to a preset second threshold value (for example, the cell voltage of a single cell reaches 200mv or 220mv), the test value of the preset characteristic parameter of the fitting trend line obtained by performing a first-order linear fit on the cell voltages of all the single cells at this time is obtained; then, the output power of the fuel cell stack is changed so that the output current of the fuel cell stack is another set value, and the output current is kept unchanged, and the above operation is repeated to obtain different test values ​​of the preset characteristic parameters of the fitting trend line obtained by performing a first-order linear fit on the cell voltages of all the single cells under different output current conditions when the operating condition of the fuel cell stack is gas shortage.

[0063] It should be noted that the intervals between the sizes of different output currents can be kept at a certain value. For example, different output currents can be set to 20%, 40%, 60%, 80%, etc. of the rated output current of the fuel cell stack.

[0064] It can be understood that based on the different output current conditions obtained by the above operation, when the operating conditions of the fuel cell stack are respectively wet, dry and gas-deficient, after performing first-order linear fitting on the cell voltages of all the single cells to obtain different test values ​​of the preset characteristic parameters of the fitting trend line, the reference values ​​of the preset characteristic parameters under different output current conditions can be determined based on the different test values ​​of the preset characteristic parameters.

[0065] Taking the preset characteristic parameter including the slope as an example, under a certain output current condition, the maximum test value and the minimum test value in the slope test value corresponding to the operating conditions of the fuel cell stack when it becomes wet, becomes dry and lacks gas can be used as the reference value of the slope. Of course, in order to adapt to the needs of the application scenario and improve the accuracy of diagnosis, the product of the maximum test value and the minimum test value in the slope test value and a preset coefficient can be used as the reference value of the slope, and the preset coefficient should be less than 1. When the preset characteristic parameter includes the maximum deviation of the single cell voltage of all single cells from the fitting trend line, the product of the absolute value of the maximum deviation test value and a preset coefficient can also be used as the reference value of the maximum deviation. In this way, by analyzing the state of the fuel cell stack working under different output currents and different operating conditions, the reference value of the preset characteristic parameter is obtained, so as to realize the multi-dimensional and accurate evaluation of the state of the fuel cell stack.

[0066] Step S104: diagnose the operating state of the fuel cell stack according to the current value of the preset characteristic parameter and the reference value of the preset characteristic parameter to obtain a diagnosis result.

[0067] It can be understood that since the reference value of the preset characteristic parameter is determined when the fuel cell stack operates at different output currents and different preset operating conditions, the operating status of the fuel cell stack can be diagnosed in combination with the current value of the preset characteristic parameter.

[0068] In one embodiment, the reference value of the slope includes a first reference value and a second reference value of the slope, and the first reference value is less than the second reference value. The operating state of the fuel cell stack is diagnosed according to the current value of the preset characteristic parameter and the reference value of the preset characteristic parameter to obtain a diagnosis result, including:

[0069] When the current value of the slope is greater than the first reference value and less than the second reference value, detect whether the current value of the maximum deviation satisfies the preset condition; if so, determine that the fuel cell stack is normal; if not, determine that the fuel cell stack is faulty. Here, the first reference value is determined based on the test value of the corresponding slope when the operating condition of the fuel cell stack is too dry, and the second reference value is determined based on the test value of the corresponding slope when the operating condition of the fuel cell stack is too wet. If the current value of the slope is greater than the first reference value and less than the second reference value, it means that the current operating condition of the fuel cell stack is neither too dry nor too wet.

[0070] Wherein, the preset condition can be set according to actual needs. In one embodiment, the reference value of the maximum deviation includes a third reference value, a fourth reference value and a fifth reference value of the maximum deviation, and the absolute value of the third reference value is greater than the absolute value of the fourth reference value, and the absolute value of the fifth reference value is greater than the absolute value of the third reference value. The preset condition includes that the absolute value of the current value of the maximum deviation is less than the absolute value of the fourth reference value. Here, the third reference value is determined based on the test value of the maximum deviation corresponding to the operating condition of the fuel cell stack when it is over-humid, the fourth reference value is determined based on the test value of the maximum deviation corresponding to the operating condition of the fuel cell stack when it is over-dry, and the fifth reference value is determined based on the test value of the maximum deviation corresponding to the operating condition of the fuel cell stack when it is short of gas. Under the premise that the current value of the slope is greater than the first reference value and less than the second reference value, if the absolute value of the current value of the maximum deviation is less than the absolute value of the fourth reference value, it means that the fuel cell stack is not over-dry, over-humid and short of gas, but other fault abnormalities, such as short circuit, collision or gas supply failure. In this way, the operating status of the fuel cell stack can be quickly and accurately diagnosed, ensuring the normal operation of the fuel cell stack.

[0071] In one embodiment, the method of diagnosing the operating state of the fuel cell stack according to the current value of the preset characteristic parameter and the reference value of the preset characteristic parameter to obtain a diagnosis result further includes: when the current value of the slope is less than the first reference value, determining that the fuel cell stack is too dry. Since the first reference value is determined based on the test value of the corresponding slope when the operating condition of the fuel cell stack is too dry, when the current value of the slope is less than the first reference value, it can be determined that the fuel cell stack is too dry, thereby realizing rapid diagnosis of the operating state of the fuel cell stack.

[0072] In one embodiment, the step of diagnosing the operating state of the fuel cell stack according to the current value of the preset characteristic parameter and the reference value of the preset characteristic parameter to obtain a diagnosis result further includes:

[0073] When the current value of the slope is greater than the second reference value, detecting whether the current value of the maximum deviation is greater than the third reference value;

[0074] If the current value of the maximum deviation is greater than the third reference value and less than the fifth reference value, it is determined that the fuel cell stack is short of gas;

[0075] If the current value of the maximum deviation is smaller than the third reference value, it is determined that the fuel cell stack is over-humidified.

[0076] It should be noted that, since the second reference value is determined based on the test value of the corresponding slope when the operating condition of the fuel cell stack is overhumidity, when the current value of the slope is greater than the second reference value, it can be determined that the fuel cell stack may be overhumidified or short of gas. At this time, if the current value of the maximum deviation is greater than the third reference value and less than the fifth reference value, it is determined that the fuel cell stack is short of gas; if the current value of the maximum deviation is less than the third reference value, it is determined that the fuel cell stack is overhumidified. In this way, the slope and maximum deviation of the fitting trend line are obtained based on fitting the real-time single cell voltages of all single cells in the fuel cell stack, so as to realize rapid and accurate diagnosis of the operating status of the fuel cell stack and ensure the normal operation of the fuel cell stack.

[0077] In summary, in the fuel cell stack diagnostic method provided in the above embodiment, the real-time single cell voltages of all single cells in the fuel cell stack are fitted to obtain the current value of the preset characteristic parameter of the fitting trend line, and then based on the relationship between the current value of the preset characteristic parameter and the reference value, the operating status of the fuel cell stack is diagnosed. No additional hardware is required, and the amount of data to be processed is small, thereby achieving real-time and accurate monitoring of the operating status of the fuel cell stack, and the operation is simple and low-cost.

[0078] In one embodiment, the method may further include:

[0079] When the fuel cell stack is over-humidified, performing at least one of the following operations on the fuel cell stack: reducing humidification, reducing pressure, increasing air flow, increasing temperature; and / or,

[0080] When the fuel cell stack is too dry, performing at least one of the following operations on the fuel cell stack: increasing humidification, increasing pressure, and reducing temperature; and / or,

[0081] When the fuel cell stack is short of gas, at least one of the following operations is performed on the fuel cell stack: increasing the air flow rate and increasing the hydrogen flow rate.

[0082] It can be understood that when the fuel cell stack is diagnosed as being too wet, lacking in air or too dry, the fuel cell stack can be returned to a normal working state by performing corresponding operations on the fuel cell stack. In addition, for different fuel cell stacks that are too dry, too wet or lacking in air, corresponding operations can be selected based on their own characteristics. It should be noted that after performing the corresponding operation on the fuel cell stack, if the slope or the value of the maximum deviation continues to increase, the fuel cell stack can be subjected to a power reduction or emergency shutdown operation. In this way, the operating conditions of the fuel cell stack are adjusted in time based on the operating state of the fuel cell stack, thereby improving the working efficiency of the fuel cell stack and improving the safety of use and service life.

[0083] Based on the same inventive concept as the above embodiments, this embodiment describes the technical solution of the above embodiments in detail through specific examples. Figure 2 , is a schematic diagram of the structure of an existing fuel cell control system, in which a fuel cell cell voltage CVM inspection controller is connected to a fuel cell controller via a CAN bus, and a fuel cell stack and a fuel cell voltage CVM inspection controller are connected via multiple cell voltage signal harnesses. The fuel cell cell voltage CVM inspection controller collects the cell voltage of each cell in the fuel cell and sends it to the fuel cell controller.

[0084] Among them, in the embodiment of the present invention, taking the slope as the fitting trend line slope and the maximum deviation of the single cell voltage of all single cells from the fitting trend line as the maximum trend line deviation as an example, the diagnosis process of the fuel cell stack diagnostic method provided in the embodiment of the present invention mainly includes two parts, one part is calibration and the other part is diagnosis.

[0085] The calibration process is as follows:

[0086] (1) When the fuel cell stack output power is 60% of the rated output power and under normal operating conditions, operate the fuel cell for 30 minutes to keep the water content and temperature of the fuel cell at normal values;

[0087] (2) Keep the output current constant and gradually make the operating conditions humid (increase humidity, reduce air flow) until the average cell voltage drops to 70% of the value before the experiment, and record the slope k of the maximum fuel cell stack cell voltage fitting trend line. max , the maximum trend line deviation of the whole process △U max . max and △U maxMultiply them by a coefficient of 0.8 as a safety value k safe and △U safewet Then, an experimental calibration is performed when the output current is 10% to 90% of the rated output current to obtain the corresponding safety value k safe and △U safewet The output current interval is adjustable, and 10% is recommended.

[0088] (3) Repeat step (1) to restore the battery stack.

[0089] (4) Keep the output current constant and gradually dry the operating conditions (reduce humidity and increase air flow) until the average cell voltage drops to 70% of the value before the experiment, and record the slope k of the maximum fuel cell stack cell voltage fitting trend line. max , the maximum trend line deviation of the whole process △U max . max and △U max Multiply them by a coefficient of 0.8 as a safety value k safe and △U safedry Then, an experimental calibration is performed when the output current is 10% to 90% of the rated output current to obtain the corresponding safety value k safe and △U safedry The output current interval is adjustable, and 10% is recommended.

[0090] (5) Repeat step (1) to restore the battery stack;

[0091] (6) Keep the output current constant and gradually reduce the air flow until the cell voltage of a cell in the fuel cell stack reaches below 200mv, and record the slope k of the maximum fuel cell stack cell voltage fitting trend line. max , the maximum trend line deviation of the whole process △U max . max and △U max Multiply them by a coefficient of 0.8 as a safety value k safe and △U safestv Then, an experimental calibration is performed when the output current is 10% to 90% of the rated output current to obtain the corresponding safety value k safe and △U safestv The output current interval is adjustable, and 10% is recommended.

[0092] (7) According to the above experimental results, the maximum k under each operating condition is combined safe With the minimum k safe , we can get the safe k value range k for each current segment safemin <k<ksafemax According to experiments, when it is too dry, k safe The value is negative, k obtained from over-humidification and air deficiency experiments safe is a positive value, and k obtained by dry experiment safe is the minimum value k safemin , k obtained from the over-humidification experiment safe is the maximum value k safemax In addition, △U safestv The absolute value is greater than △U safewet The absolute value of △U safewet The absolute value of is greater than △U safedry The absolute value of △U safestv >△U safewet >△U safedry .

[0093] It should be noted that a linear fit can be performed based on the data of the single cell voltages of all single cells in the fuel cell stack, so that the overall trend of the single cell voltage can be seen, whether it decreases toward the intake end of the fuel cell stack or toward the position of the fuel cell stack away from the intake end, as well as the extent of the decrease. Figure 3 This is a schematic diagram of the cell voltage distribution and fitting when the fuel cell stack is over-humidified. Figure 3 It can be seen that under the condition of relatively sufficient gas, when it is overhumid, the voltage on the intake side of the fuel cell stack will usually be higher, and the voltage far away from the intake side will be lower, and the single cell voltage distribution will show an inclined state. Figure 4 This is a schematic diagram of the single cell voltage distribution and fitting when the fuel cell stack is too dry. Figure 4 It can be seen that when the air is too dry, the voltage on the intake side of the fuel cell stack will usually be lower, and the voltage far away from the intake side will be higher, and the single cell voltage distribution will also show an inclined state. Figure 5 This is a schematic diagram of the deviation of the cell voltage after fitting when the fuel cell stack is short of gas, as shown in Figure 5 As shown in the figure, when the battery is short of air, its voltage distribution is similar to that of the battery when it is over-humidified, but one battery voltage deviates far from the fitted trend line, that is, there is a maximum deviation. Therefore, by combining the deviation of the fitted line and the battery voltage, we can further distinguish between short of air and over-humidification. Figure 3 and Figure 4 In the figure, the horizontal axis represents the serial number of the single cell, i.e. the position of the single cell voltage, the vertical axis represents the voltage magnitude, and the dotted line represents the fitting trend line. Although the characteristics of each fuel cell stack are different, the voltage distribution trend is generally consistent, and the above trends and deviations can be calibrated through experiments. Therefore, through the above fitting, a k value can be used to reflect the trend of the single cell voltage distribution. Through this trend and the above experimental calibration, the fuel cell stack status can be diagnosed through the fuel cell stack voltage.

[0094] See also Figure 6, is a schematic diagram of a specific flow chart of a fuel cell stack diagnostic method provided by an embodiment of the present invention, the method comprising the following steps:

[0095] Step S201: obtaining in real time the slope k of the fitted trend line of the fuel cell stack cell voltage and the real-time maximum trend line deviation △U;

[0096] Specifically, the fuel cell controller performs a first-order linear fitting on the fuel cell stack cell voltage in real time to obtain the fitting trend line slope k and the real-time maximum trend line deviation ΔU.

[0097] Here, when fitting the cell voltage distribution, it is necessary to fit the cell voltage distribution to a linear straight line expressed in the form of y=kx+a, where k is the slope of the fitting line.

[0098] Step S202: Query the k corresponding to the output current safemin , k safemax , △U safewet , △U safestv and △U safedry ;

[0099] Specifically, based on the above calibration process, query the k corresponding to the current output current safemin , k safemax , △U safewet , △U safestv and △U safedry .

[0100] Step S203: Determine k safemin <k<k safemax Is it established? If so, execute step S204; otherwise, execute step S207;

[0101] Step S204: Determine whether the absolute value of △U is less than △U safedry If yes, execute step S205, otherwise execute step S206;

[0102] Step S205: Determine other abnormal faults of the fuel cell stack; here, the other abnormal faults of the fuel cell stack may be uncommon faults such as short circuit, collision or gas supply failure.

[0103] Step S206: determining that the fuel cell stack is normal;

[0104] Step S207: Determine whether k < k safemin Is it true? If so, go to step S208; otherwise, go to step S209;

[0105] Step S208: determining that the fuel cell stack is too dry;

[0106] Here, if k < ksafemin This is not true, indicating that k>k safemax , the fuel cell stack may be too wet or lack of air.

[0107] Step S209: Determine △U safewet <△U<△U safestv Is it established? If so, execute step S210; otherwise, execute step S211;

[0108] Step S210: determining that the fuel cell stack is short of gas;

[0109] Step S211: When △U<△U safewet When the fuel cell stack is judged to be too wet;

[0110] Step S212: further controlling the fuel cell according to the diagnosis result.

[0111] Here, if the fuel cell stack is judged to be too dry, the humidification is increased, the pressure is increased, and the temperature is appropriately reduced; if the fuel cell stack is judged to be over-humidified, the humidification is reduced, the pressure is reduced, the flow rate is increased, and the temperature is increased; if the fuel cell stack is judged to be short of gas, the air flow rate and the hydrogen flow rate are increased. If k and △U still increase, the power reduction or emergency shutdown is executed.

[0112] It should be noted that, because the characteristics of each fuel cell stack are different, the appropriate countermeasures are also different. For example, when it is too dry, any of these measures, such as increasing humidification, increasing pressure, and appropriately lowering the temperature, can restore the fuel cell stack from being too dry, but different fuel cell stacks have different characteristics, so it can be preferred. When it is too wet, any of these measures, such as reducing humidification, reducing pressure, increasing flow, and increasing temperature, can restore the stack from being too wet, but different fuel cell stacks have different characteristics, so it can be preferred. Here, it can be specifically achieved by jointly controlling the air compressor, dehumidification valve, and hydrogen path drain valve in the fuel cell system.

[0113] In summary, the fuel cell stack diagnostic method provided in this embodiment has the following innovations:

[0114] 1) It integrates the fuel cell stack voltage distribution characteristic values ​​such as the minimum single cell voltage, the maximum single cell voltage, the average single cell voltage, the slope of the single cell voltage trend line, and the deviation between the single cell voltage and the trend line, and uses these values ​​to perform real-time diagnosis of the fuel cell stack status;

[0115] 2) It can diagnose the fuel cell stack status of being too dry, too wet, lacking in gas, other faults, normal operation, etc. in real time online. It can also analyze the status of the fuel cell stack offline by collecting the single cell voltage data, and optimize and calibrate the threshold and trigger condition setting of fault diagnosis through big data;

[0116] 3) There is no need to add an additional controller to the fuel cell stack. It is only necessary to judge the characteristic value of the collected fuel cell stack cell voltage through a logical algorithm, which not only saves processor computing resources, but also can effectively and accurately diagnose the status of the fuel cell stack.

[0117] The fuel cell stack diagnostic method provided in this embodiment has the following advantages:

[0118] 1) Ability to evaluate the operating status of the fuel cell stack online in real time, including over-dryness, over-humidity, lack of gas, and other faults;

[0119] 2) The diagnosed fuel cell stack operating status can guide the control system to optimize the fuel cell stack operating conditions, and can also adjust the fuel cell stack operating conditions in real time according to the diagnosis status, so that the fuel cell can operate stably and efficiently;

[0120] 3) In the current fuel cell stack module, there is no need to add a new controller. It is only necessary to use the fuel cell voltage patrol controller that comes with the fuel cell to collect the fuel cell cell voltage and transmit the characteristic value describing the cell voltage trend to the fuel cell controller;

[0121] 4) It does not rely on the operating conditions and environment of the fuel cell stack, nor does it require complex big data conversion. It can be implemented by an ordinary MCU microprocessor. The solution has low cost and strong feasibility.

[0122] Based on the same inventive concept as the above embodiments, the present invention provides a fuel cell stack diagnostic device, such as Figure 7 As shown, the device includes: a processor 110 and a memory 111 for storing a computer program that can be run on the processor 110; wherein, Figure 7 The processor 110 shown in the figure is not used to indicate that the number of the processor 110 is one, but is only used to indicate the positional relationship of the processor 110 relative to other devices. In actual applications, the number of the processor 110 may be one or more; similarly, Figure 7 The memory 111 shown in the figure has the same meaning, that is, it is only used to refer to the position relationship of the memory 111 relative to other devices. In practical applications, the number of memories 111 can be one or more. The processor 110 is used to implement the fuel cell stack diagnostic method when running the computer program.

[0123] The device may also include: at least one network interface 112. The various components in the device are coupled together via a bus system 113. It is understood that the bus system 113 is used to achieve connection and communication between these components. In addition to the data bus, the bus system 113 also includes a power bus, a control bus, and a status signal bus. However, for the sake of clarity, Figure 7 Various buses are labeled as bus system 113 .

[0124] The memory 111 may be a volatile memory or a nonvolatile memory, or may include both volatile and nonvolatile memories. The nonvolatile memory may be a read-only memory (ROM), a programmable read-only memory (PROM), an erasable programmable read-only memory (EPROM), an electrically erasable programmable read-only memory (EEPROM), a ferromagnetic random access memory (FRAM), a flash memory, a magnetic surface memory, an optical disk, or a compact disc read-only memory (CD-ROM); the magnetic surface memory may be a disk memory or a tape memory. The volatile memory may be a random access memory (RAM), which is used as an external cache. By way of example and not limitation, many forms of RAM are available, such as static random access memory (SRAM), synchronous static random access memory (SSRAM), dynamic random access memory (DRAM), synchronous dynamic random access memory (SDRAM), double data rate synchronous dynamic random access memory (DDRSDRAM), enhanced synchronous dynamic random access memory (ESDRAM), synchronous link dynamic random access memory (SLDRAM, SyncLink Dynamic Random Access Memory), and direct RAM bus random access memory (DRRAM, Direct Rambus Random Access Memory).The memory 111 described in the embodiments of the present invention is intended to include but is not limited to these and any other suitable types of memories.

[0125] The memory 111 in the embodiment of the present invention is used to store various types of data to support the operation of the device. Examples of these data include: any computer program used to operate on the device, such as an operating system and an application; contact data; phone book data; messages; pictures; videos, etc. Among them, the operating system includes various system programs, such as a framework layer, a core library layer, a driver layer, etc., which are used to implement various basic services and process hardware-based tasks. The application program may include various applications, such as a media player (Media Player), a browser (Browser), etc., which are used to implement various application services. Here, the program that implements the method of the embodiment of the present invention may be included in the application program.

[0126] Based on the same inventive concept as the above-mentioned embodiment, this embodiment further provides a computer storage medium, in which a computer program is stored. The computer storage medium may be a ferromagnetic random access memory (FRAM), a read-only memory (ROM), a programmable read-only memory (PROM), an erasable programmable read-only memory (EPROM), an electrically erasable programmable read-only memory (EEPROM), a flash memory, a magnetic surface memory, an optical disc, or a compact disc read-only memory (CD-ROM) or the like; it may also be various devices including one or any combination of the above-mentioned memories, such as a mobile phone, a computer, a tablet device, a personal digital assistant, etc. When the computer program stored in the computer storage medium is executed by the processor, the above-mentioned fuel cell stack diagnostic method is implemented. For the specific steps implemented when the computer program is executed by the processor, please refer to Figure 1 The description of the illustrated embodiment will not be repeated here.

[0127] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0128] In this document, the terms "comprises," "comprising," or any other variations thereof, are intended to cover a non-exclusive inclusion of elements other than those listed and may also include additional elements not expressly listed.

[0129] The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art can easily think of changes or substitutions within the technical scope disclosed by the present invention, which should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. A fuel cell stack diagnostic method, characterized in that: The method comprises: Obtaining the current output current of the fuel cell and the current cell voltages of all cells in the fuel cell stack; Performing a first-order linear fit on the cell voltages of all the single cells to obtain current values ​​of preset characteristic parameters of the fitting trend line; the preset characteristic parameters include a slope and a maximum deviation between the cell voltages of all the single cells and the fitting trend line; Searching a preset database according to the current output current, obtaining a reference value of the preset characteristic parameter corresponding to the current output current; wherein the preset database stores reference values ​​of preset characteristic parameters corresponding to controlling the fuel cell stack to operate under different output currents and different preset operating conditions; the reference value of the slope includes a second reference value of the slope; the reference value of the maximum deviation includes a third reference value and a fifth reference value of the maximum deviation, and the absolute value of the fifth reference value is greater than the absolute value of the third reference value; Diagnosing the operating state of the fuel cell stack according to the current value of the preset characteristic parameter and the reference value of the preset characteristic parameter to obtain a diagnosis result, including: When the current value of the slope is greater than the second reference value, detecting whether the current value of the maximum deviation is greater than the third reference value; If the current value of the maximum deviation is greater than the third reference value and less than the fifth reference value, it is determined that the fuel cell stack is short of gas; If the current value of the maximum deviation is smaller than the third reference value, it is determined that the fuel cell stack is over-humidified.

2. The method according to claim 1, characterized in that The reference value of the slope also includes a first reference value of the slope and the first reference value is less than the second reference value, and the operating state of the fuel cell stack is diagnosed according to the current value of the preset characteristic parameter and the reference value of the preset characteristic parameter to obtain a diagnosis result, and further includes: When the current value of the slope is greater than the first reference value and less than the second reference value, detecting whether the current value of the maximum deviation satisfies a preset condition; If the conditions are met, it is determined that the fuel cell stack is normal; If not, it is determined that the fuel cell stack is faulty.

3. The method according to claim 2, characterized in that The reference value of the maximum deviation also includes a fourth reference value of the maximum deviation, and the absolute value of the third reference value is greater than the absolute value of the fourth reference value, and the preset condition includes that the absolute value of the current value of the maximum deviation is less than the absolute value of the fourth reference value.

4. The method according to claim 2, characterized in that: The step of diagnosing the operating state of the fuel cell stack according to the current value of the preset characteristic parameter and the reference value of the preset characteristic parameter to obtain a diagnosis result further includes: When the current value of the slope is less than the first reference value, it is determined that the fuel cell stack is too dry.

5. The method according to claim 1, characterized in that Before obtaining the current output current of the fuel cell and the current cell voltages of all the cells in the fuel cell stack, the method further includes: Under the set output current, the fuel cell stack is controlled to operate under preset operating conditions, and after the average value of the cell voltages of all the cells in the fuel cell stack drops to a preset first threshold value or the cell voltage of at least one cell is less than a preset second threshold value, a test value of a preset characteristic parameter of a fitting trend line obtained by performing a first-order linear fit on the cell voltages of all the cells is obtained; According to the test value of the preset characteristic parameter, a reference value of the preset characteristic parameter when the fuel cell stack operates under the set output current and preset operating conditions is determined.

6. The method according to any one of claims 1 to 5, characterized in that: Also includes: When the fuel cell stack is over-humidified, performing at least one of the following operations on the fuel cell stack: reducing humidification, reducing pressure, increasing air flow, increasing temperature; and / or, When the fuel cell stack is too dry, performing at least one of the following operations on the fuel cell stack: increasing humidification, increasing pressure, and reducing temperature; and / or, When the fuel cell stack is short of gas, at least one of the following operations is performed on the fuel cell stack: increasing the air flow rate and increasing the hydrogen flow rate.

7. A fuel cell stack diagnostic device, characterized in that: The device includes a processor and a memory for storing a program; when the program is executed by the processor, the processor implements the fuel cell stack diagnostic method as described in any one of claims 1 to 6.

8. A computer storage medium, characterized in that: A computer program is stored, and when the computer program is executed by a processor, the fuel cell stack diagnostic method according to any one of claims 1 to 6 is implemented.

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