Method and apparatus for flooding diagnosis of fuel cell

Abstract

The invention provides a flooding diagnosis method for a fuel cell, which comprises the following steps: acquiring a time-varying pressure difference signal of a fuel cell stack, the pressure difference signal comprises an anode pressure difference signal which changes along with time between a feed port and a discharge port on the anode side and / or a cathode pressure difference signal which changes along with time between a feed port and a discharge port on the cathode side; converting the pressure difference signal into a pressure difference frequency domain signal of the fuel cell stack; and introducing the pressure difference frequency domain signal as an evaluation factor, and evaluating the flooding state of the anode side and / or the cathode side of the fuel cell stack. The invention also relates to an apparatus and a computer program product for flooding diagnosis of a fuel cell. According to the invention, the frequency domain characteristic of the pressure difference signal of the fuel cell stack is fully utilized, the flooding state of the anode side and / or the cathode side of the fuel cell stack can be rapidly and accurately judged, and the severity of the flooding fault can be evaluated without adding additional measurement hardware equipment.

Description

Technical Field

[0001] The present invention relates to the field of fuel cells, and in particular to a method for diagnosing flooding in a fuel cell, a device for diagnosing flooding in a fuel cell, and a computer program product for at least assisting in implementing the steps of the method according to the present invention. Background Art

[0002] During the operation of a fuel cell, it is necessary to monitor the state of health (SOH) of the fuel cell. For example, flooding in the fuel cell is a common fault that affects the state of health of the fuel cell. Water generated by the electrochemical reaction of hydrogen and oxygen on the cathode side of the fuel cell stack may accumulate. When too much water accumulates on the cathode side of the stack, cathode flooding occurs, which affects the flow rate of the air flow channel, and further leads to unstable performance of the fuel cell. At the same time, due to the concentration gradient, the water accumulated on the cathode side of the stack will diffuse to the anode side of the stack. When too much water accumulates on the anode side of the stack, anode flooding occurs, which affects the flow rate of the hydrogen flow channel, even causes blockage of the hydrogen flow channel, and also causes corrosion of the anode carbon plate of the fuel cell and damages the anode structure, thereby leading to damage or performance degradation of the fuel cell stack.

[0003] Therefore, how to quickly, accurately and at low cost diagnose the flooding fault of a fuel cell has become a technical problem to be solved at present. Summary of the Invention

[0004] The object of the present invention is to provide a method for diagnosing flooding in a fuel cell, a device for diagnosing flooding in a fuel cell, and a computer program product to at least partially solve the problems in the prior art.

[0005] According to a first aspect of the present invention, there is provided a method for diagnosing flooding in a fuel cell, the method comprising:

[0006] - Step S1: Obtain a pressure difference signal P(t) that changes with time of a fuel cell stack, where the pressure difference signal P(t) includes an anode pressure difference signal P 12 (t) that changes with time between the inlet and outlet of the anode side and / or a cathode pressure difference signal P 34 (t) that changes with time between the inlet and outlet of the cathode side;

[0007] - Step S2: Convert the pressure difference signal P(t) into a pressure difference frequency domain signal P(f) of the fuel cell stack; and

[0008] - Step S3: Introduce the pressure difference frequency domain signal P(f) as an evaluation factor to evaluate the flooding state of the anode side and / or the cathode side of the fuel cell stack.

[0009] The core concept of the present invention lies in: making full use of the frequency-domain characteristics of the pressure difference signal of the fuel cell stack. When the amplitude fluctuation of the pressure difference frequency-domain signal P(f) significantly increases in a certain or certain preset frequency-domain intervals, it is possible to quickly and accurately determine the flooding state on the anode side and / or the cathode side of the fuel cell stack. In particular, it is also possible to evaluate the severity of the flooding fault without adding additional measurement hardware devices.

[0010] According to an optional embodiment of the present invention, in step S1, it is also possible to obtain the voltage signal V(t) that changes with time of the fuel cell stack, and calculate the standard deviation S of the voltage signal within a pre-given time period. V And in step S3, it is also possible to introduce the standard deviation S of the pressure difference signal P(t) and the voltage signal. V As evaluation factors, to evaluate the flooding state on the anode side and / or the cathode side of the fuel cell stack.

[0011] According to another optional embodiment of the present invention, step S3 may at least include:

[0012] - Step S31: Judge the standard deviation S of the voltage signal V(t). V Whether the deviation from the first preset standard deviation threshold S ref1 is greater than the first preset threshold ε1;

[0013] - Step S32: If the deviation of the standard deviation S of the voltage signal V(t) V from the first preset standard deviation threshold S ref1 is less than or equal to the first preset threshold ε1, it is determined that there is no flooding state on the anode side and / or the cathode side of the fuel cell stack;

[0014] - Step S33: If the deviation of the standard deviation S of the voltage signal V(t) V from the first preset standard deviation threshold S ref1 is greater than the first preset threshold ε1, then judge whether the standard deviation S of the pressure difference frequency-domain signal P(f) in the preset frequency-domain interval P from the second preset standard deviation threshold S ref2 is greater than the second preset threshold ε2; and

[0015] - Step S34: If the deviation of the standard deviation S of the pressure difference frequency-domain signal P(f) in the preset frequency-domain interval P from the second preset standard deviation threshold S ref2 is greater than the second preset threshold ε2, it is determined that there is a flooding state on the anode side and / or the cathode side of the fuel cell stack.

[0016] According to another alternative embodiment of the present invention, in step S34, a flooding fault level on the anode side and / or the cathode side of the fuel cell stack can be evaluated based on the pressure difference signal P(t), wherein it is determined whether the anode pressure difference signal P 12 (t) and / or the cathode pressure difference signal P 34 (t) is greater than a third preset threshold ε3. If the anode pressure difference signal P 12 (t) and / or the cathode pressure difference signal P 34 (t) of the fuel cell stack is greater than the third preset threshold ε3, a first flooding fault level on the anode side and / or the cathode side of the fuel cell stack is determined; if the anode pressure difference signal P 12 (t) and / or the cathode pressure difference signal P 34 (t) of the fuel cell stack is less than or equal to the third preset threshold ε3, a second flooding fault level on the anode side and / or the cathode side of the fuel cell stack is determined, wherein the first flooding fault level is higher than the second flooding fault level.

[0017] According to another alternative embodiment of the present invention, step S3 may further include:

[0018] - Step S35: If the standard deviation S P of the pressure difference frequency domain signal P(f) in the frequency domain interval is less than or equal to a second preset threshold ε2, it is determined whether the anode pressure difference signal P 12 (t) and / or the cathode pressure difference signal P 34 (t) is greater than a third preset threshold ε3;

[0019] - Step S36: If the anode pressure difference signal P 12 (t) and / or the cathode pressure difference signal P 34 (t) of the fuel cell stack is greater than the third preset threshold ε3, it is determined that there is no flooding state on the anode side and / or the cathode side of the fuel cell stack; and

[0020] - Step S37: If the anode pressure difference signal P 12 (t) and / or the cathode pressure difference signal P 34 (t) of the fuel cell stack is less than or equal to the third preset threshold ε3, another fuel cell flooding diagnosis method is used to further evaluate the flooding state on the anode side and / or the cathode side of the fuel cell stack.

[0021] According to another alternative embodiment of the present invention, in the said another fuel cell flooding diagnosis method, the flooding state on the anode side and / or the cathode side of the fuel cell stack can be further evaluated based on the electrolyte membrane impedance, anode impedance and / or cathode impedance of the fuel cell.

[0022] According to another alternative embodiment of the present invention, the pressure difference signal P(t) can be converted into the pressure difference frequency domain signal P(f) of the fuel cell stack through Fourier transform or wavelet transform.

[0023] According to another alternative embodiment of the present invention, the preset frequency domain interval is related to the water flow characteristics of the fuel cell stack, where the influencing factors of the water flow characteristics include, for example, the structure of the fuel cell stack, the hydrophilic index of the bipolar plate of the fuel cell, and / or the current density of the fuel cell, etc.

[0024] According to a second aspect of the present invention, there is provided a device for diagnosing flooding in a fuel cell, the device comprising the following components:

[0025] - A pressure detection unit configured to obtain a pressure difference signal P(t) that changes with time of the fuel cell stack, the pressure difference signal P(t) including an anode pressure difference signal P 12 (t) that changes with time between the inlet and outlet of the anode side and / or a cathode pressure difference signal P 34 (t) that changes with time between the inlet and outlet of the cathode side; and

[0026] - A control unit configured to execute the method according to the present invention.

[0027] According to another alternative embodiment of the present invention, the device may further include a voltage detection unit configured to obtain a voltage signal V(t) that changes with time of the fuel cell stack.

[0028] According to a third aspect of the present invention, there is provided a computer program product, such as a computer-readable program carrier, containing computer program instructions, and when the computer program instructions are executed by a processor, they at least assist in implementing the steps of the method according to the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Next, the present invention will be described in more detail by referring to the accompanying drawings, and the principles, features, and advantages of the present invention can be better understood. The accompanying drawings include:

[0030] Figure 1 Showing a flowchart of a method for diagnosing flooding in a fuel cell according to an exemplary embodiment of the present invention;

[0031] Figure 2 Showing a schematic structural block diagram of a fuel cell according to an exemplary embodiment of the present invention;

[0032] Figure 3A flowchart of a method for diagnosing waterlogging in a fuel cell according to another exemplary embodiment of the present invention is shown;

[0033] Figure 4 A flowchart of a method for diagnosing waterlogging in a fuel cell according to another exemplary embodiment of the present invention is shown; and

[0034] Figure 5 A schematic structural block diagram of a device for diagnosing waterlogging in a fuel cell according to an exemplary embodiment of the present invention is shown. Detailed implementation manners

[0035] In order to make the technical problems to be solved, technical solutions and beneficial technical effects of the present invention clearer, the present invention will be further described in detail below with reference to the drawings and multiple exemplary embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention, rather than to limit the protection scope of the present invention.

[0036] Figure 1 A flowchart of a method for diagnosing waterlogging in a fuel cell according to an exemplary embodiment of the present invention is shown. The following exemplary embodiments describe the method according to the present invention in more detail.

[0037] The method may include steps S1 to S3. In step S1, a pressure difference signal P(t) that changes with time of the fuel cell stack is obtained. In the current embodiment of the present invention, the pressure difference signal P(t) may include an anode pressure difference signal that changes with time between the inlet and outlet of the anode side and / or a cathode pressure difference signal that changes with time between the inlet and outlet of the cathode side. The following will be elaborated in detail with reference to Figure 2 the schematic structural block diagram of a fuel cell according to an exemplary embodiment of the present invention shown.

[0038] As Figure 2 shown, fuel (such as hydrogen) is input into the anode 101 of the fuel cell stack 100. Hydrogen molecules (H2) are dissociated into hydrogen ions (H+) and electrons (e-) under the action of the anode catalyst. H+ moves towards the cathode 102 through the electrolyte layer of the fuel cell stack, and e- flows to the cathode through an external circuit because it cannot pass through the electrolyte layer. At the same time, oxygen (O2) is input into the cathode of the battery. Oxygen is dissociated into oxygen atoms (O) under the action of the cathode catalyst, and combines with e- flowing to the cathode through the external circuit and H+ passing through the electrolyte layer to generate water (H2O), thereby completing the electrochemical reaction and releasing heat. These waters may accumulate on the cathode side and cause a waterlogging state on the cathode side. At the same time, due to the existence of a concentration gradient or gas supersaturation at the inlet, the water generated on the cathode side may also diffuse to the anode side and accumulate, thereby causing a waterlogging state on the anode side.

[0039] To obtain the pressure difference signal P(t) that varies with time for the fuel cell stack 100, a first pressure detection unit 111 may be provided at the inlet of the anode 101 of the fuel cell stack 100 to collect the first pressure P1(t) at the inlet of the anode 101 over time; a second pressure detection unit 112 may be provided at the outlet of the anode 101 of the fuel cell stack 100 to collect the second pressure P2(t) at the outlet of the anode 101 over time; a third pressure detection unit 113 may be provided at the inlet of the cathode 102 of the fuel cell stack 100 to collect the third pressure P3(t) at the inlet of the cathode 102 over time; and a fourth pressure detection unit 114 may be provided at the outlet of the cathode 102 of the fuel cell stack 100 to collect the fourth pressure P4(t) at the outlet of the cathode 102 over time. Here, the anode pressure difference signal P 12 (t) between the inlet and outlet on the anode side can be calculated as the difference between the first pressure P1(t) and the second pressure P2(t), which is recorded as data varying with time over time; the cathode pressure difference signal P 34 (t) between the inlet and outlet on the cathode side can be calculated as the difference between the third pressure P3(t) and the fourth pressure P4(t), which is also recorded as data varying with time over time.

[0040] In step S2, the pressure difference signal P(t) is converted into the pressure difference frequency domain signal P(f) of the fuel cell stack 100. Here, the pressure difference signal P(t) that varies with time can be regarded as a time domain signal, which is used to characterize the distribution of the pressure difference amplitude varying with time, i.e., the signal time characteristics, while the pressure difference frequency domain signal P(f) can be used to characterize the distribution of the pressure difference amplitude varying with frequency, i.e., the signal frequency characteristics. Optionally, the pressure difference signal P(t) can be converted into the pressure difference frequency domain signal P(f) of the fuel cell stack 100 through Fourier transform or wavelet transform. Compared with Fourier transform, wavelet transform can achieve local transformation in the time domain and frequency domain. For example, through operations such as stretching and translation, multi-scale refinement analysis of the signal can be performed, so that more effective information can be extracted from the signal.

[0041] In step S3, the pressure difference frequency domain signal P(f) is introduced as an evaluation factor to evaluate the flooding state of the anode side and / or the cathode side of the fuel cell stack 100. In the normal operating state of the fuel cell stack 100, the pressure difference frequency domain signal P(f) is usually a white noise signal within a certain frequency domain range, that is, the power spectral density is constant within this frequency domain range. When the amplitude fluctuation of the pressure difference frequency domain signal P(f) significantly increases in a certain or certain preset frequency domain intervals, it can be determined that there is a flooding state on the anode side and / or the cathode side of the fuel cell stack 100. The preset frequency domain intervals with significantly increased amplitude fluctuations can be related to the flow characteristics of water in the fuel cell stack 100, and the flow characteristics of water are in turn related to the following influencing factors: for example, the structure of the fuel cell stack 100 will affect the flow rate and flow direction of water in the fuel cell stack 100, the hydrophilic index of the bipolar plate of the fuel cell will affect the flow rate of water in the fuel cell stack 100, and the current density of the fuel cell will affect the water production flow rate of the fuel cell stack 100, and so on. The present invention precisely utilizes this frequency domain characteristic of the pressure difference signal to evaluate the flooding state of the fuel cell stack 100.

[0042] Optionally, in step S1, a voltage signal V(t) that changes with time of the fuel cell stack 100 can also be obtained, and the standard deviation S of the voltage signal V(t) within a pre-given time period is calculated. V Here, the voltage detection unit 13 can collect the voltage signal V(t) that changes with time of the fuel cell stack 100 at a fixed frequency (for example, 10 times per second), and calculate the standard deviation S of the voltage signal amplitude within a pre-given time period (for example, 2 seconds) through the following formula. V :

[0043]

[0044] Where V i represents the voltage value of the fuel cell stack 100 collected at the i-th signal acquisition moment, V a represents the average value of the voltage signals of the fuel cell stack 100 collected within a pre-given time period, and n represents the number of voltage signals of the fuel cell stack 100 collected within a pre-given time period.

[0045] In another optional embodiment of the present invention, in the case of introducing the pressure difference frequency domain signal P(f) as an evaluation factor, the pressure difference signal P(t) and the standard deviation S of the voltage signal can also be introduced V as evaluation factors to evaluate the flooding state of the anode side and / or the cathode side of the fuel cell stack 100. Next, in combination with Figure 3The flowchart of the method for diagnosing flooding in a fuel cell according to another exemplary embodiment of the present invention shown below elaborates step S3. Only the differences from the embodiment shown in Figure 1 are elaborated below, and the same steps are not repeated for the sake of brevity.

[0046] As Figure 3 shown, step S3 may at least include steps S31 to S34. In step S31, it is determined whether the deviation of the standard deviation S V of the voltage signal V(t) from the first preset standard deviation threshold S ref1 is greater than the first preset threshold ε1. If the deviation of the standard deviation S V of the voltage signal V(t) from the first preset standard deviation threshold S ref1 is less than or equal to the first preset threshold ε1, that is, there is no obvious amplitude fluctuation in the voltage signal, then in step S32, it can be determined that there is no flooding state on the anode side and / or the cathode side of the fuel cell stack 100.

[0047] If the deviation of the standard deviation S V of the voltage signal V(t) from the first preset standard deviation threshold S ref1 is greater than the first preset threshold ε1, that is, there is an obvious amplitude fluctuation in the voltage signal, then it is necessary to further perform the flooding diagnosis of the fuel cell stack 100 based on the pressure difference frequency domain signal P(f) and the pressure difference signal P(t) varying with time. In step S33, it is determined whether the deviation of the standard deviation S P of the pressure difference frequency domain signal P(f) in the preset frequency domain interval from the second preset standard deviation threshold S ref2 is greater than the second preset threshold ε2. Here, the standard deviation S P is used to characterize the fluctuation of the pressure difference frequency domain signal P(f) in the preset frequency domain interval, and it can be calculated, for example, by the following formula:

[0048]

[0049] where, F i represents the amplitude of the i-th pressure difference frequency domain signal in the preset frequency domain interval, F a represents the average value of the amplitudes of all pressure difference frequency domain signals in the preset frequency domain interval, and m represents the number of pressure difference frequency domain signals in the preset frequency domain interval.

[0050] If the standard deviation S P of the pressure difference frequency domain signal P(f) in the frequency domain interval from the second preset standard deviation threshold S ref2If the deviation is greater than the second preset threshold ε2, that is, the amplitude fluctuation of the pressure difference frequency domain signal P(f) in the preset frequency domain interval is significantly enhanced, then in step S34, it can be determined that there is a waterlogging state on the anode side and / or the cathode side of the fuel cell stack 100.

[0051] In another alternative embodiment of the present invention, in step S34, the waterlogging fault level on the anode side and / or the cathode side of the fuel cell stack 100 can also be evaluated based on the pressure difference signal P(t). Exemplarily, it can be determined whether the anode pressure difference signal P 12 (t) and / or the cathode pressure difference signal P 34 (t) is greater than the third preset threshold ε3. If the anode pressure difference signal P 12 (t) and / or the cathode pressure difference signal P 34 (t) is greater than the third preset threshold ε3, then the first waterlogging fault level on the anode side and / or the cathode side of the fuel cell stack 100 is determined, where the first waterlogging fault level is higher than the second waterlogging fault level mentioned below. For example, when the anode pressure difference signal P 12 (t) is greater than the third preset threshold ε 31 , the first waterlogging fault level on the anode side of the fuel cell stack 100 is determined; when the cathode pressure difference signal P 34 (t) is greater than another third preset threshold ε 32 , the first waterlogging fault level on the cathode side of the fuel cell stack 100 is determined, where the third preset threshold ε 31 and the third preset threshold ε 32 can be equal or different from each other. In the case of the first waterlogging fault level, a serious waterlogging condition appears on the anode side and / or the cathode side of the fuel cell stack 100, which may cause a reverse polarization risk, that is, the cathode potential is higher than the anode potential, which will cause corrosion of the anode carbon plate of the fuel cell and damage the anode structure, thereby shortening the service life and reducing the performance. If the anode pressure difference signal P 12 (t) and / or the cathode pressure difference signal P 34 (t) is less than or equal to the third preset threshold ε3, then the second waterlogging fault level on the anode side and / or the cathode side of the fuel cell stack 100 is determined. In the case of the second waterlogging fault level, a slight waterlogging condition appears on the anode side and / or the cathode side of the fuel cell stack 100, which will cause, for example, a decrease in the output power, output voltage and / or energy conversion efficiency of the fuel cell.

[0052] Figure 4The flowchart of a method for diagnosing waterlogging in a fuel cell according to another exemplary embodiment of the present invention is shown. Only the differences from the embodiment shown in Figure 3 are described below, and the same steps are not repeated for the sake of brevity.

[0053] As Figure 4 shown, the step S3 may further include steps S35 to S37. If the standard deviation S of the pressure difference frequency domain signal P(f) in the frequency domain interval P is less than or equal to the second preset threshold ε2, the waterlogging diagnosis of the fuel cell stack 100 may be further performed based on the pressure difference signal P(t). In step S35, it is determined whether the anode pressure difference signal P of the fuel cell stack 100 12 (t) and / or the cathode pressure difference signal P 34 (t) is greater than the third preset threshold ε3. If the anode pressure difference signal P of the fuel cell stack 100 12 (t) and / or the cathode pressure difference signal P 34 (t) is greater than the third preset threshold ε3, then in step S36, it is determined that there is no waterlogging state on the anode side and / or the cathode side of the fuel cell stack 100, but the amplitude fluctuations of the anode pressure difference signal P of the fuel cell stack 100 12 (t) and / or the cathode pressure difference signal P 34 (t) are caused by non-waterlogging factors (such as the opening and closing of valves at the inlet and / or outlet). The non-waterlogging factors can be further explored based on the operating state of the fuel cell components.

[0054] If the anode pressure difference signal P of the fuel cell stack 100 12 (t) and / or the cathode pressure difference signal P 34 (t) is less than or equal to the third preset threshold ε3, then in step S37, another fuel cell waterlogging diagnosis method is used to further evaluate the waterlogging state on the anode side and / or the cathode side of the fuel cell stack 100. For example, in the another fuel cell waterlogging diagnosis method, an alternating current signal with a predetermined frequency may be applied to the fuel cell stack 100, and the electrolyte membrane impedance, anode impedance, and / or cathode impedance may be calculated from the output voltage and output current corresponding to the alternating current signal of the fuel cell stack 100, and then the waterlogging state on the anode side and / or the cathode side of the fuel cell stack 100 may be further evaluated based on the electrolyte membrane impedance, anode impedance, and / or cathode impedance of the fuel cell.

[0055] It should be noted that the described additional fuel cell waterlogging diagnosis method is not limited to the diagnosis methods listed above, but may include all fuel cell waterlogging diagnosis methods in the prior art that are different from the fuel cell waterlogging diagnosis method of the present invention. In addition, the magnitudes of the various preset thresholds and preset standard deviation thresholds mentioned in the present invention can be adjusted according to the actual operating parameters of the fuel cell.

[0056] According to the present invention, by making full use of the frequency domain characteristics of the pressure difference signal of the fuel cell stack and combining the standard deviations of the pressure difference signal and the voltage signal of the fuel cell stack, it is possible to quickly and accurately evaluate the waterlogging state on the anode side and / or the cathode side of the fuel cell stack, and in particular, it is also possible to evaluate the severity of the waterlogging fault, without the need to add additional measurement hardware devices.

[0057] In addition, it should be noted that the step numbers described herein do not necessarily represent the order of precedence, but are merely a kind of reference numeral. According to specific circumstances, the order can be changed as long as the technical purpose of the present invention can be achieved.

[0058] Figure 5 Fig. 10 shows a schematic structural block diagram of a device 1 for diagnosing waterlogging in a fuel cell according to an exemplary embodiment of the present invention.

[0059] As Figure 5 shown, the device 1 may include the following components: a pressure detection unit 11 configured to obtain a pressure difference signal P(t) that changes with time of the fuel cell stack, where the pressure difference signal P(t) includes an anode pressure difference signal P 12 (t) that changes with time between the inlet and outlet of the anode side and / or a cathode pressure difference signal P 34 (t) that changes with time between the inlet and outlet of the cathode side. Among them, the pressure detection unit 11 includes, for example, a first pressure detection unit 111 provided at the inlet of the anode 101 of the fuel cell stack 100, a second pressure detection unit 112 provided at the outlet of the anode 101 of the fuel cell stack 100, a third pressure detection unit 113 provided at the inlet of the cathode 102 of the fuel cell stack 100, and a fourth pressure detection unit 114 provided at the outlet of the cathode 102 of the fuel cell stack 100; and a control unit 12 configured to execute the method according to the present invention.

[0060] Optionally, the device 1 further includes a voltage detection unit 13 configured to obtain a voltage signal V(t) that changes with time of the fuel cell stack 100.

[0061] It should be understood that in this text, the expressions "first", "second", "third", etc. are only for descriptive purposes and should not be construed as indicating or implying relative importance, nor should they be construed as implicitly specifying the number of the indicated technical features.

[0062] Although specific embodiments have been described above, these embodiments are not intended to limit the scope of the present disclosure, even in the case where a single embodiment is described only with respect to a specific feature. The feature examples provided in the present disclosure are for illustrative purposes only and not for limitation, unless otherwise stated. In specific implementations, multiple features can be combined with each other according to actual needs and where technically feasible. Various substitutions, changes, and modifications can also be conceived without departing from the spirit and scope of the present invention.

Claims

1. A method for diagnosing flooding in a fuel cell, the method comprising: Step S1: Obtain a pressure difference signal P(t) that varies with time for the fuel cell stack (100), where the pressure difference signal P(t) includes an anode pressure difference signal P 12 (t) that varies with time between the inlet and outlet on the anode side and / or a cathode pressure difference signal P 34 (t) that varies with time between the inlet and outlet on the cathode side; Step S2: Convert the pressure difference signal P(t) into a pressure difference frequency domain signal P(f) of the fuel cell stack (100); and Step S3: Introduce the pressure difference frequency domain signal P(f) as an evaluation factor to evaluate the flooding state of the anode side and / or the cathode side of the fuel cell stack (100).

2. The method according to claim 1, wherein In step S1, a voltage signal V(t) that changes with time of the fuel cell stack (100) is also acquired, and a standard deviation S of the voltage signal within a pre-given time period is calculated. V Moreover, in step S3, the pressure difference signal P(t) and the standard deviation S of the voltage signal are also introduced. V As evaluation factors, the flooding states of the anode side and / or the cathode side of the fuel cell stack (100) are evaluated.

3. The method according to claim 2, wherein The step S3 at least includes: Step S31: Determine the standard deviation S of the voltage signal V(t) V and the deviation of the first preset standard deviation threshold S ref1 is greater than the first preset threshold ε1; Step S32: If the standard deviation S of the voltage signal V(t) V and the first preset standard deviation threshold S ref1 have a deviation less than or equal to the first preset threshold ε1, it is determined that there is no flooding state on the anode side and / or the cathode side of the fuel cell stack (100); Step S33: If the standard deviation S of the voltage signal V(t) V deviates from the first preset standard deviation threshold S ref1 by more than the first preset threshold ε1, then determine whether the deviation of the standard deviation S of the pressure difference frequency domain signal P(f) in the preset frequency domain interval from the second preset standard deviation threshold S P is greater than the second preset threshold ε2; and ref2 ​ Step S34: If the standard deviation S of the pressure difference frequency domain signal P(f) in a preset frequency domain interval P and a second preset standard deviation threshold S ref2 has a deviation greater than a second preset threshold ε2, it is determined that a water flooding state exists on the anode side and / or the cathode side of the fuel cell stack (100).

4. The method according to claim 3, wherein In step S34, a flooding fault level on the anode side and / or the cathode side of the fuel cell stack (100) is evaluated based on the pressure difference signal P(t), wherein it is determined whether the anode pressure difference signal P 12 (t) and / or the cathode pressure difference signal P 34 (t) is greater than a third preset threshold ε3. If the anode pressure difference signal P 12 (t) and / or the cathode pressure difference signal P 34 (t) of the fuel cell stack (100) is greater than the third preset threshold ε3, a first flooding fault level on the anode side and / or the cathode side of the fuel cell stack (100) is determined; if the anode pressure difference signal P 12 (t) and / or the cathode pressure difference signal P 34 (t) of the fuel cell stack (100) is less than or equal to the third preset threshold ε3, a second flooding fault level on the anode side and / or the cathode side of the fuel cell stack (100) is determined, wherein the first flooding fault level is higher than the second flooding fault level.

5. The method according to claim 3, wherein The step S3 further includes: Step S35: If the standard deviation S of the pressure difference frequency domain signal P(f) in the frequency domain interval P is less than or equal to the second preset threshold ε2, then determine whether the anode pressure difference signal P 12 (t) and / or the cathode pressure difference signal P 34 (t) is greater than the third preset threshold ε3; Step S36: If the anode pressure difference signal P 12 (t) and / or the cathode pressure difference signal P 34 (t) is greater than the third preset threshold ε3, it is determined that there is no flooding state on the anode side and / or the cathode side of the fuel cell stack (100); and Step S37: If the anode pressure difference signal P 12 (t) and / or the cathode pressure difference signal P 34 (t) is less than or equal to the third preset threshold ε3, then use another fuel cell flooding diagnosis method to further evaluate the flooding state of the anode side and / or the cathode side of the fuel cell stack (100).

6. The method according to claim 5, wherein In the additional fuel cell flooding diagnosis method, further evaluate the flooding state of the anode side and / or the cathode side of the fuel cell stack (100) based on the electrolyte membrane impedance, anode impedance, and / or cathode impedance of the fuel cell.

7. The method according to any one of claims 1 to 6, wherein Convert the pressure difference signal P(t) into the pressure difference frequency domain signal P(f) of the fuel cell stack (100) through Fourier transform or wavelet transform.

8. The method according to any one of claims 3 to 6, wherein The preset frequency domain interval is related to the water flow characteristics in the fuel cell stack (100), wherein the influencing factors of the water flow characteristics include the structure of the fuel cell stack (100), the hydrophilic index of the bipolar plate of the fuel cell, and / or the current density of the fuel cell.

9. A device (1) for diagnosing flooding in a fuel cell, the device (1) comprising the following components: A pressure detection unit (11) configured to obtain a pressure difference signal P(t) that varies with time of the fuel cell stack, the pressure difference signal P(t) including an anode pressure difference signal P 12 (t) that varies with time between the inlet and outlet of the anode side and / or a cathode pressure difference signal P 34 (t) that varies with time between the inlet and outlet of the cathode side; and A control unit (12) configured to execute the method according to any one of claims 1 to 8.

10. The device (1) according to claim 9, wherein The device (1) further includes a voltage detection unit (13), which is configured to obtain a voltage signal V(t) that changes with time of the fuel cell stack (100).

11. A computer program product, such as a computer-readable program carrier, comprising computer program instructions which, when executed by a processor, at least assist in implementing the steps of the method according to any one of claims 1 to 8.

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