Fuel cell stack operation humidity abnormity diagnosis method

Abstract

The invention discloses a fuel cell stack operation humidity abnormity diagnosis method. The method comprises the following steps: acquiring current state information of a stack; determining a consistency state quantity according to the current state information of the electric pile; determining a voltage difference between the maximum single battery voltage and the minimum single battery voltage and an average single battery voltage according to the single battery voltage; according to the voltage difference and the average single battery voltage, the voltage abnormal state quantity of the electric pile is determined; according to the pressure difference between the in-pile hydrogen pressure and the out-pile hydrogen pressure, the abnormal state quantity of electric pile power generation is determined; according to the high-frequency impedance value, determining an impedance value abnormal rising state quantity and an impedance value abnormal reducing state quantity; according to the consistency state quantity, the voltage abnormal state quantity, the power generation abnormal state quantity, the impedance value abnormal rising state quantity and the impedance value abnormal reducing state quantity, determining the humidity abnormal state of the electric pile; the humidity abnormal state comprises a film dry fault state and a water logging fault state. By means of the method, the humidity abnormal state of the electric pile can be accurately and rapidly determined.

Description

Technical Field

[0001] The present invention relates to the technical field of vehicle fuel cells, and in particular to a method for diagnosing abnormal humidity during operation of a fuel cell stack. Background Art

[0002] A hydrogen fuel cell is a device that converts chemical energy into electrical energy. It mainly includes a fuel cell stack, a fuel supply system, an air supply system, water and heat management, and an electronic control unit. The working principle of a proton exchange membrane fuel cell is to pass humidified high-purity hydrogen into the anode and humidified air or oxygen into the cathode. High-purity hydrogen generates hydrogen ions and electrons under the action of the anode catalyst layer. The hydrogen ions generated at the anode will reach the cathode through the proton exchange membrane in the form of hydrated hydrogen ions. Oxygen combines with hydrated hydrogen ions under the action of the cathode catalyst to generate water and release heat. Electrons flow from the anode to the cathode from the external circuit to generate current. For a fuel cell stack, abnormal humidity diagnosis of the stack is a key technology of the fuel cell stack system. The timely discovery of abnormal humidity and the determination of the degree are the basis for subsequent humidity control, which directly determines the quality of the stack operation and the life of the stack.

[0003] The existing determination of humidity anomalies in fuel cell stacks usually requires the addition of processors and sensors to the fuel cell system to diagnose humidity anomalies in the stack based on parameters such as ambient temperature and humidity. However, this method only uses parameters such as ambient temperature and humidity to determine humidity anomalies without considering the actual operating parameters of the stack, which increases the possibility of misjudgment and reduces the service life of the stack. Summary of the invention

[0004] The present invention provides a method for diagnosing abnormal humidity in the operation of a fuel cell stack, so as to accurately determine the abnormal humidity in the fuel cell stack by acquiring the current status information of the stack operation, reduce the risk of misjudgment, ensure the stable operation of the stack, and improve the service life of the stack.

[0005] The present invention provides a method for diagnosing abnormal humidity in a fuel cell stack operation, which is applied to a vehicle and comprises:

[0006] Obtaining current status information of the fuel cell stack; the current status information of the fuel cell stack includes at least the single cell voltage of the fuel cell stack, the hydrogen pressure entering the stack, the hydrogen pressure leaving the stack, and the real-time high-frequency impedance of the fuel cell stack;

[0007] Determine the consistency state quantity of the battery stack according to the current state information of the battery stack;

[0008] Determine the voltage difference between the maximum single cell voltage and the minimum single cell voltage and the average single cell voltage according to the single cell voltage;

[0009] Determine the voltage abnormal state quantity of the battery stack according to the voltage difference and the average single cell voltage, combined with a preset voltage difference threshold and a preset average single cell voltage threshold;

[0010] Determine the abnormal power generation state of the fuel cell stack according to the pressure difference between the hydrogen pressure entering the stack and the hydrogen pressure leaving the stack, combined with a preset pressure difference threshold;

[0011] According to the high-frequency impedance value, determine the abnormal increase state quantity of the impedance value of the battery stack and the abnormal decrease state quantity of the impedance value;

[0012] The abnormal humidity state of the fuel cell stack is determined based on the consistency state quantity, the abnormal voltage state quantity, the abnormal power generation state quantity, the abnormal impedance value increase state quantity and the abnormal impedance value decrease state quantity; the abnormal humidity state of the fuel cell stack includes a membrane dry fault state and a water flooding fault state.

[0013] Optionally, the current status information also includes the stack inlet air pressure, stack inlet air flow, coolant outlet temperature and coolant inlet temperature;

[0014] According to the current status information of the battery stack, the consistency status of the battery stack is determined, including:

[0015] According to the hydrogen pressure entering the stack and in combination with the preset hydrogen pressure entering the stack, the consistency state quantity of the hydrogen pressure entering the stack is determined;

[0016] Determine the consistency state quantity of the stack-entering air pressure according to the stack-entering air pressure and the preset stack-entering air pressure;

[0017] According to the stack air flow rate, combined with the preset stack air flow rate, the consistency state quantity of the stack air flow rate is determined;

[0018] According to the coolant outlet temperature and the preset coolant outlet temperature, a consistency state quantity of the coolant outlet temperature is determined;

[0019] According to the coolant inlet temperature and in combination with the preset coolant inlet temperature, the consistency state quantity of the coolant inlet temperature is determined.

[0020] Optionally, the consistency state quantity of the hydrogen pressure entering the stack is determined according to the hydrogen pressure entering the stack in combination with the preset hydrogen pressure entering the stack, including:

[0021] According to the hydrogen pressure entering the stack, combined with the preset hydrogen pressure entering the stack, based on the first calculation formula, the consistency state quantity of the hydrogen pressure entering the stack is determined; the first calculation formula is: STphin = (Phinset-Phinact) / Phinset, wherein Phinact is the hydrogen pressure entering the stack, Phinset is the preset hydrogen pressure entering the stack, and STphin is the consistency state quantity of the hydrogen pressure entering the stack;

[0022] According to the stack-entering air pressure and the preset stack-entering air pressure, the consistency state quantity of the stack-entering air pressure is determined, including:

[0023] According to the stack-entering air pressure and the preset stack-entering air pressure, the consistency state quantity of the stack-entering air pressure is determined based on the second calculation formula; the second calculation formula is: STpo=(Poset-Poact) / Poset, wherein Poact is the stack-entering air pressure, Poset is the preset stack-entering air pressure, and STpo is the consistency state quantity of the stack-entering air pressure;

[0024] According to the air flow rate of entering the stack, combined with the preset air flow rate of entering the stack, the consistency state quantity of the air flow rate of entering the stack is determined, including:

[0025] According to the stack-entering air flow rate, combined with the preset stack-entering air flow rate, based on the third calculation formula, the consistency state quantity of the stack-entering air flow rate is determined; the third calculation formula is: STma=(Maset-Maact) / Maset, wherein Maact is the stack-entering air flow rate, Maset is the preset stack-entering air flow rate, and STma is the consistency state quantity of the stack-entering air flow rate;

[0026] According to the coolant outlet temperature, combined with the preset coolant outlet temperature, the consistency state quantity of the coolant outlet temperature is determined, including:

[0027] According to the coolant outlet temperature, combined with the preset coolant outlet temperature, based on the fourth calculation formula, the consistency state quantity of the coolant outlet temperature is determined; the fourth calculation formula is: STtwo=(Twoset-Twoact) / Twoset, wherein Twoact is the coolant outlet temperature, Twoset is the preset coolant outlet temperature, and STtwo is the consistency state quantity of the coolant outlet temperature;

[0028] According to the coolant inlet temperature, combined with the preset coolant inlet temperature, the consistency state quantity of the coolant inlet temperature is determined, including:

[0029] According to the coolant inlet temperature and the preset coolant inlet temperature, the consistency state quantity of the coolant inlet temperature is determined based on the fifth calculation formula; the fifth calculation formula is STtwi = (Twiset-Twiact) / Twiset, wherein Twiact is the coolant inlet temperature, Twiset is the preset coolant inlet temperature, and STtwi is the consistency state quantity of the coolant inlet temperature.

[0030] Optionally, when STphin≤A, the consistency state quantity of the hydrogen pressure entering the stack is 1; when STphin>A, the consistency state quantity of the hydrogen pressure entering the stack is 0; and / or,

[0031] When STpo≤A, the consistency state quantity of the air pressure entering the stack is 1; when STpo>A, the consistency state quantity of the air pressure entering the stack is 0; and / or,

[0032] When STma≤A, the consistency state quantity of the air flow entering the stack is 1; when STma>A, the consistency state quantity of the air flow entering the stack is 0; and / or,

[0033] When STtwo≤A, the consistency state quantity of the coolant outlet temperature is 1; when STtwo>A, the consistency state quantity of the coolant outlet temperature is 0; and / or,

[0034] When STtwi≤A, the consistency state quantity of the coolant inlet temperature is 1; when STtwi>A, the consistency state quantity of the coolant inlet temperature is 0;

[0035] Wherein, A is a constant, 0<A≤20%.

[0036] Optionally, the voltage abnormal state quantity of the battery stack is determined according to the voltage difference and the average single cell voltage, in combination with a preset voltage difference threshold and a preset average single cell voltage threshold, including:

[0037] When (Vcmax-Vcmin)≥Vcdifset, Vcave≤Vcaveset, and the voltage abnormal state quantity of the battery stack is determined to be 1 for a first preset time;

[0038] When (Vcmax-Vcmin)<Vcdifset, or Vcave>Vcaveset, or the duration is less than the first preset time, the voltage abnormal state quantity of the battery stack is determined to be 0; wherein Vcmax-Vcmin is the voltage difference, Vcdifset is the preset voltage difference threshold, Vcave is the average single cell voltage, and Vcaveset is the preset average single cell voltage threshold.

[0039] Optionally, the abnormal power generation state quantity of the fuel cell stack is determined according to the pressure difference between the hydrogen pressure entering the stack and the hydrogen pressure leaving the stack, in combination with a preset pressure difference threshold, including:

[0040] When Phdifact≤Phdifset and the condition lasts for a second preset time, determining that the abnormal power generation state quantity of the battery stack is 1;

[0041] When Phdifact>Phdifset, or the duration is less than the second preset time, it is determined that the abnormal power generation state quantity of the fuel cell stack is 0; wherein Phdifact is the pressure difference, and Phdifset is the preset pressure difference threshold.

[0042] Optionally, determining the abnormal increase state quantity of the impedance value of the battery stack and the abnormal decrease state quantity of the impedance value according to the high-frequency impedance value includes:

[0043] Calculate the deviation value of the high-frequency impedance value within a third preset time according to the high-frequency impedance value and the preset high-frequency impedance threshold;

[0044] According to the high-frequency impedance value and the deviation value, combined with a preset high-frequency impedance threshold and a preset high-frequency impedance value upper deviation threshold, determining a state quantity of abnormally increased impedance value of the battery stack;

[0045] According to the high-frequency impedance value and the deviation value, combined with the preset high-frequency impedance threshold and the deviation threshold under the preset high-frequency impedance value, the abnormal reduction state quantity of the impedance value of the battery stack is determined.

[0046] Optionally, according to the high-frequency impedance value and the deviation value, in combination with a preset high-frequency impedance threshold and a preset high-frequency impedance value upper deviation threshold, determining the abnormal increase state quantity of the impedance value of the battery stack includes:

[0047] When Rstack≥Rset, Rstackdif≥Rstackup, and the condition lasts for a fourth preset time, determining that the impedance value of the stack is abnormally increased as 1;

[0048] When Rstack<Rset, or Rstackdif<Rstackup, or the duration is less than the fourth preset time, the abnormal increase state of the impedance value of the fuel cell stack is determined to be 0; wherein Rstack is the high-frequency impedance value, Rset is the preset high-frequency impedance threshold, Rstackdif is the deviation value, and Rstackup is the upper deviation threshold of the preset high-frequency impedance value.

[0049] Optionally, according to the high-frequency impedance value and the deviation value, in combination with a preset high-frequency impedance threshold and a preset high-frequency impedance value deviation threshold, determining the abnormal decrease state quantity of the impedance value of the battery stack includes:

[0050] When Rstack<Rset, Rstackdif≤Rstackdo, and the condition lasts for a fourth preset time, determining that the impedance value of the stack is abnormally reduced as 1;

[0051] When Rstack≥Rset, or Rstackdif>Rstackdo, or the duration is less than the fourth preset time, it is determined that the abnormal decrease state of the impedance value of the fuel cell stack is 0; wherein Rstack is the high-frequency impedance value, Rset is the preset high-frequency impedance threshold, Rstackdif is the deviation value, and Rstackdo is the deviation threshold under the preset high-frequency impedance value.

[0052] Optionally, determining the abnormal humidity state of the battery stack according to the consistency state quantity, the voltage abnormal state quantity, the power generation abnormal state quantity, the impedance value abnormal increase state quantity and the impedance value abnormal decrease state quantity includes:

[0053] When the consistency state quantity is 1, the voltage abnormal state quantity is 1, the power generation abnormal state quantity is 1, and the impedance value abnormal increase state quantity is 1, the humidity abnormal state of the battery stack is determined to be a membrane dry fault state;

[0054] When the consistency state quantity is 1, the voltage abnormal state quantity is 1, the power generation abnormal state quantity is 1, and the impedance value abnormal reduction state quantity is 1, the humidity abnormal state of the battery stack is determined to be a water flooding fault state.

[0055] The technical solution of the present invention obtains the current state information of the battery stack; the current state information of the battery stack includes at least the single cell voltage, the hydrogen pressure entering the stack, the hydrogen pressure leaving the stack and the real-time high-frequency impedance of the battery stack; according to the current state information of the battery stack, the consistency state quantity of the battery stack is determined; according to the single cell voltage, the voltage difference between the maximum single cell voltage and the minimum single cell voltage and the average single cell voltage are determined; and according to the voltage difference and the average single cell voltage, in combination with a preset voltage difference threshold and a preset average single cell voltage threshold, the voltage abnormal state quantity of the battery stack is determined; according to the pressure difference between the hydrogen pressure entering the stack and the hydrogen pressure leaving the stack, in combination with a preset pressure difference threshold, the power generation abnormal state quantity of the battery stack is determined; according to the high-frequency impedance value, the impedance value abnormal increase state quantity and the impedance value abnormal decrease state quantity of the battery stack are determined; according to the consistency state quantity, the voltage abnormal state quantity, the power generation abnormal state quantity, the impedance value abnormal increase state quantity and the impedance value abnormal decrease state quantity, the humidity abnormal state of the battery stack is determined; the humidity abnormal state of the battery stack includes a membrane dry fault state and a water flooding fault state. By using the above method, by obtaining the current status information of the fuel cell stack operation, the humidity abnormality of the fuel cell stack can be accurately determined, which greatly reduces the risk of misjudgment, ensures the stable operation of the fuel cell stack, and improves the service life of the fuel cell stack.

[0056] It should be understood that the contents described in this section are not intended to identify the key or important features of the embodiments of the present invention, nor are they intended to limit the scope of the present invention. Other features of the present invention will become easily understood through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0057] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0058] Figure 1A flow chart of a method for diagnosing abnormal humidity in a fuel cell stack operation provided by an embodiment of the present invention;

[0059] Figure 2 A flow chart of a second method for diagnosing abnormal humidity in a fuel cell stack operation provided by an embodiment of the present invention;

[0060] Figure 3 A flowchart of a third method for diagnosing abnormal operating humidity of a fuel cell stack provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0061] In order to enable those skilled in the art to better understand the scheme of the present invention, the technical scheme in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0062] It should be noted that the terms "first", "second", etc. in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units that are clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0063] In one embodiment, Figure 1 This is a flow chart of a method for diagnosing abnormal humidity in a fuel cell stack according to an embodiment of the present invention. This embodiment is applicable to diagnosing and determining the cause of abnormal humidity in a fuel cell stack. The method can be executed by a controller, which can be configured in a vehicle. Figure 1 As shown, the method includes:

[0064] S110, obtaining current status information of the battery stack.

[0065] Among them, the current status information of the fuel cell stack includes at least the single cell voltage of the fuel cell stack, the hydrogen pressure entering the stack, the hydrogen pressure leaving the stack and the real-time high-frequency impedance of the fuel cell stack.

[0066] The method of acquiring the voltage of a single cell of the stack may include but is not limited to acquisition through a CVM controller. The method of acquiring the hydrogen pressure entering the stack may include but is not limited to acquisition through a hydrogen pressure sensor entering the stack. The method of acquiring the hydrogen pressure leaving the stack may include but is not limited to acquisition through a hydrogen pressure sensor leaving the stack. The method of acquiring the real-time high-frequency impedance of the stack may include but is not limited to acquisition through an AC impedance spectrum acquisition device.

[0067] S120. Determine the consistency state quantity of the battery stack according to the current state information of the battery stack.

[0068] Among them, the size of the consistency state quantity of the battery stack can indicate the supply situation of the battery stack and determine whether the battery stack is in a normal operating state.

[0069] Specifically, after obtaining the current state information of the battery stack, the consistency state quantity of the battery stack can be determined by a certain calculation formula based on the obtained current state information of the battery stack and the design value of the current state information of the battery stack. Under normal circumstances, the consistency state quantity of the battery stack may include 1 or 0, 1 indicates that the battery stack is supplied normally and is in a normal operating state; 0 indicates that the battery stack is supplied abnormally and is in an abnormal operating state.

[0070] S130 , determining a voltage difference between a maximum cell voltage and a minimum cell voltage and an average cell voltage according to the cell voltages.

[0071] S140, determining the voltage abnormality state quantity of the battery stack according to the voltage difference and the average single cell voltage, in combination with a preset voltage difference threshold and a preset average single cell voltage threshold.

[0072] Among them, the maximum single cell voltage is the maximum value of the voltage of each cell in the battery stack. The minimum single cell voltage is the minimum value of the voltage of each cell in the battery stack. The average single cell voltage is the average value of the single cell voltage calculated by adding the voltages of each cell in the battery stack and dividing it by the number of single cells. The preset voltage differential threshold is the voltage differential threshold between the maximum single cell voltage and the minimum single cell voltage of the battery stack set in advance. The determination of the preset voltage differential threshold may include but is not limited to determining by a two-dimensional chart with a pre-calibrated corresponding relationship, wherein the abscissa of the two-dimensional chart is the battery stack output current, and the ordinate is the corresponding preset voltage differential threshold. The battery stack output current can be obtained by a current sensor or the like. The preset average single cell voltage threshold is the average single cell voltage threshold set in advance. Similarly, the determination of the average single cell voltage threshold may include but is not limited to determining by a two-dimensional chart with a pre-calibrated corresponding relationship, wherein the abscissa of the two-dimensional chart is the battery stack output current, and the ordinate is the corresponding preset average single cell voltage threshold. The requirements for different thresholds under different battery stack working conditions can be better matched by using the battery stack output current through a two-dimensional chart. The voltage abnormality state quantity of the battery stack may indicate whether the voltage of the battery stack is abnormal. The value of the voltage abnormality state quantity of the battery stack may include 0 and 1, where 0 indicates that the voltage of the battery stack is normal and 1 indicates that the voltage of the battery stack is abnormal.

[0073] Specifically, after obtaining the cell voltages of the battery stack, the maximum cell voltage, the minimum cell voltage and the average cell voltage are determined from the obtained cell voltages, and the determined maximum cell voltage and the minimum cell voltage are subtracted to determine the voltage difference. After determining the voltage difference and the average cell voltage, the voltage abnormality state of the battery stack can be determined by combining the preset voltage difference threshold and the preset average cell voltage threshold and using a certain judgment method.

[0074] S150, determining the abnormal power generation state quantity of the fuel cell stack according to the pressure difference between the hydrogen pressure entering the stack and the hydrogen pressure leaving the stack in combination with a preset pressure difference threshold.

[0075] Among them, the preset pressure differential threshold value represents the pressure differential threshold value calibrated in advance. The determination of the preset pressure differential threshold value may include but is not limited to determination through a three-dimensional chart of the corresponding relationship calibrated in advance, in which the X-axis is the output current of the stack, the Y-axis is the coolant temperature out of the stack, and the Z-axis is the corresponding preset pressure differential threshold value. Since the amount of hydrogen consumed by the stack under normal working conditions is fixed under different working conditions, the pressure differential between the hydrogen pressure entering the stack and the hydrogen pressure leaving the stack under different working conditions should be approximately fixed. If the pressure differential value suddenly decreases to a certain value, it means that the amount of hydrogen consumed by the stack is reduced and the working state of the stack is abnormal. In this embodiment, the requirements for different preset pressure differential threshold values ​​under different working conditions of the stack can be better matched by looking up the three-dimensional chart with the output current of the stack and the coolant temperature out of the stack.

[0076] Specifically, after obtaining the hydrogen pressure entering the stack and the hydrogen pressure leaving the stack, the pressure difference between the hydrogen pressure entering the stack and the hydrogen pressure leaving the stack can be determined, and based on the pressure difference, combined with the preset pressure difference threshold, and using certain judgment conditions, the abnormal power generation state of the fuel cell stack can be determined.

[0077] S160. Determine the abnormal increase state quantity and the abnormal decrease state quantity of the impedance value of the battery stack according to the high-frequency impedance value.

[0078] Among them, the high-frequency impedance value is a parameter that can intuitively reflect the water content in the battery stack. The state quantity of the abnormal increase in the impedance value of the battery stack is a parameter reflecting the abnormal increase in the impedance value of the battery stack, and the state quantity of the abnormal decrease in the impedance value is a parameter reflecting the decrease in the impedance value of the battery stack. The state quantity of the abnormal increase in the impedance value can be expressed as 1 and 0, 1 indicates that the impedance value is abnormally increased, and 0 indicates that the impedance value is normally increased. Similarly, the state quantity of the abnormal decrease in the impedance value can be expressed as 1 and 0, 1 indicates that the impedance value is abnormally decreased, and 0 indicates that the impedance value is normally decreased.

[0079] Specifically, after the high-frequency impedance value is obtained, according to the obtained high-frequency impedance value, combined with the high-frequency impedance threshold and the high-frequency impedance value deviation threshold, certain judgment conditions are used to determine the abnormal increase state quantity of the impedance value of the battery stack and the abnormal decrease state quantity of the impedance value. Exemplarily, the high-frequency impedance value deviation threshold may include an upper deviation threshold and a lower deviation threshold. The upper deviation threshold, the high-frequency impedance value, and the high-frequency impedance threshold can be used to determine the abnormal increase state quantity of the impedance value of the battery stack; the lower deviation threshold, the high-frequency impedance value, and the high-frequency impedance threshold can be used to determine the abnormal decrease state quantity of the impedance value of the battery stack.

[0080] S170. Determine the abnormal humidity state of the battery stack based on the consistency state quantity, the voltage abnormal state quantity, the power generation abnormal state quantity, the impedance value abnormal increase state quantity and the impedance value abnormal decrease state quantity.

[0081] The abnormal humidity state of the battery stack includes a membrane dry fault state and a water flood fault state. The membrane dry fault state indicates that the battery stack is in an over-dry state, and the water flood fault state indicates that the battery stack is in an over-humid state.

[0082] Specifically, after determining the consistency state quantity, voltage abnormal state quantity, power generation abnormal state quantity, impedance value abnormal increase state quantity and impedance value abnormal decrease state quantity of the battery stack, when the consistency state quantity of the battery stack is 1, that is, when the battery stack is in a normal operating state, the humidity abnormal state of the battery stack is determined according to the voltage abnormal state quantity, power generation abnormal state quantity, impedance value abnormal increase state quantity and impedance value abnormal decrease state quantity of the battery stack. Specifically, the membrane dry state quantity of the battery stack can be determined according to the voltage abnormal state quantity, power generation abnormal state quantity and impedance value abnormal increase state quantity of the battery stack, so as to determine whether the battery stack is in a membrane dry fault state. When the membrane dry state quantity is 1, the battery stack is in a membrane dry fault state; when the membrane dry state quantity is 0, the battery stack is not in a membrane dry fault state. Similarly, the water flooding state quantity of the battery stack can be determined according to the voltage abnormal state quantity, power generation abnormal state quantity and impedance value abnormal decrease state quantity of the battery stack, so as to determine whether the battery stack is in a water flooding fault state. When the water flooding state quantity is 1, the battery stack is in a water flooding fault state; when the water flooding state quantity is 0, the battery stack is not in a water flooding fault state. This enables diagnosis of the cause of abnormal humidity in the battery stack.

[0083] The technical solution of the embodiment of the present invention is to obtain the current state information of the battery stack; the current state information of the battery stack includes at least the single cell voltage, the hydrogen pressure entering the stack, the hydrogen pressure leaving the stack and the real-time high-frequency impedance of the battery stack; determine the consistency state quantity of the battery stack according to the current state information of the battery stack; determine the voltage difference between the maximum single cell voltage and the minimum single cell voltage and the average single cell voltage according to the single cell voltage; and determine the voltage abnormal state quantity of the battery stack according to the voltage difference and the average single cell voltage, in combination with a preset voltage difference threshold and a preset average single cell voltage threshold; determine the power generation abnormal state quantity of the battery stack according to the pressure difference between the hydrogen pressure entering the stack and the hydrogen pressure leaving the stack, in combination with a preset pressure difference threshold; determine the impedance value abnormal increase state quantity and the impedance value abnormal decrease state quantity of the battery stack according to the high-frequency impedance value; determine the humidity abnormal state of the battery stack according to the consistency state quantity, the voltage abnormal state quantity, the power generation abnormal state quantity, the impedance value abnormal increase state quantity and the impedance value abnormal decrease state quantity; the humidity abnormal state of the battery stack includes a membrane dry fault state and a water flooding fault state. By using the above method, by obtaining the current status information of the fuel cell stack operation, the humidity abnormality of the fuel cell stack can be accurately determined, which greatly reduces the risk of misjudgment, ensures the stable operation of the fuel cell stack, and improves the service life of the fuel cell stack.

[0084] In another specific embodiment, optionally, Figure 2 This is a flow chart of the second fuel cell stack operating humidity abnormality diagnosis method provided by an embodiment of the present invention. This embodiment refines the specific implementation method of S120 in the above embodiment, which determines the consistency state quantity of the stack according to the current state information of the stack. The contents that are not yet detailed in this embodiment can be referred to the above embodiment, and will not be repeated here. Figure 2 As shown, the method includes:

[0085] S210, obtaining current status information of the battery stack.

[0086] The current status information also includes the air pressure entering the stack, the air flow entering the stack, the coolant outlet temperature and the coolant inlet temperature.

[0087] The method for obtaining the air pressure entering the stack may include but is not limited to collecting and obtaining through the air pressure sensor entering the stack, the method for obtaining the air flow entering the stack may include but is not limited to collecting and obtaining through the air flow sensor entering the stack, the method for obtaining the coolant outlet temperature may include but is not limited to collecting and obtaining through the coolant outlet temperature sensor, and the method for obtaining the coolant inlet temperature may include but is not limited to collecting and obtaining through the coolant inlet temperature sensor, etc.

[0088] S211. Determine the consistency state quantity of the hydrogen pressure entering the stack according to the hydrogen pressure entering the stack and in combination with the preset hydrogen pressure entering the stack.

[0089] Among them, this step can be further refined as follows: according to the hydrogen pressure entering the stack, combined with the preset hydrogen pressure entering the stack, based on the first calculation formula, determine the consistency state quantity of the hydrogen pressure entering the stack; the first calculation formula is: STphin = (Phinset-Phinact) / Phinset, wherein Phinact is the hydrogen pressure entering the stack, Phinset is the preset hydrogen pressure entering the stack, and STphin is the consistency state quantity of the hydrogen pressure entering the stack.

[0090] The preset hydrogen pressure entering the stack may be a design value of the hydrogen pressure entering the stack or an empirical value set based on experience, etc.

[0091] Specifically, when determining the consistency state quantity of the fuel cell stack, it is necessary to determine all relevant parameters that can reflect the fuel cell stack operating status information. First, the consistency state quantity of the hydrogen pressure entering the stack is determined. According to the acquired hydrogen pressure entering the stack and the set preset hydrogen pressure entering the stack, based on the first calculation formula of STphin = (Phinset-Phinact) / Phinset, the hydrogen pressure entering the stack Phinact and the preset hydrogen pressure entering the stack Phinset are both known. After substituting them into the first calculation formula, the consistency state quantity STphin of the hydrogen pressure entering the stack can be obtained. When the calculated consistency state quantity of the hydrogen pressure entering the stack STphin≤A, wherein A is a constant greater than 0 and less than or equal to 20%, such as A can be 5%, 10%, 15% or 20%, which can be determined specifically according to actual conditions. This step is illustrated by taking A=10% as an example. When STphin≤10%, it indicates that the deviation between the actually obtained hydrogen pressure entering the stack and the preset hydrogen pressure entering the stack is less than or equal to 10%, which is within the set deviation range. The conformity between the hydrogen pressure entering the stack and the preset hydrogen pressure entering the stack is relatively high. At this time, the corresponding consistency state quantity of the hydrogen pressure entering the stack is 1, that is, the hydrogen pressure entering the stack is within the normal range. When the calculated consistency state quantity STphin of the hydrogen pressure entering the stack>A, A=10%, it indicates that the deviation between the actual hydrogen pressure entering the stack and the preset hydrogen pressure entering the stack is greater than 10%, which is outside the set deviation range, and the conformity between the hydrogen pressure entering the stack and the preset hydrogen pressure entering the stack is low. At this time, the corresponding consistency state quantity of the hydrogen pressure entering the stack is 0, that is, the hydrogen pressure entering the stack is not within the normal range.

[0092] S212: Determine the consistency state quantity of the stack-entering air pressure according to the stack-entering air pressure and the preset stack-entering air pressure.

[0093] Among them, this step can be further refined as follows: according to the air pressure entering the stack and in combination with the preset air pressure entering the stack, based on the second calculation formula, the consistency state quantity of the air pressure entering the stack is determined; the second calculation formula is: STpo=(Poset-Poact) / Poset, wherein Poact is the air pressure entering the stack, Poset is the preset air pressure entering the stack, and STpo is the consistency state quantity of the air pressure entering the stack.

[0094] The preset stack-entry air pressure may be a design value of the stack-entry air pressure or an empirical value set based on experience.

[0095] Specifically, when determining the consistency state quantity of the stack-entering air pressure, according to the acquired stack-entering air pressure and the set preset stack-entering air pressure, based on the second calculation formula of STpo=(Poset-Poact) / Poset, the stack-entering air pressure Poact and the preset stack-entering air pressure Poset are both known, and after being substituted into the second calculation formula, the consistency state quantity STpo of the stack-entering air pressure can be obtained. When the calculated consistency state quantity STpo of the stack-entering air pressure is ≤A, where A is a constant greater than 0 and less than or equal to 20%, and exemplarily A=10%, it indicates that the deviation between the actually acquired stack-entering air pressure and the preset stack-entering air pressure is less than or equal to 10%, which is within the set deviation range, and the conformity between the stack-entering air pressure and the preset stack-entering air pressure is high. At this time, the corresponding consistency state quantity of the stack-entering air pressure is 1, that is, the stack-entering air pressure is within the normal range. When the calculated consistency state quantity STpo of the stack entry air pressure is greater than A, exemplarily, A=10%, it indicates that the deviation between the actually obtained stack entry air pressure and the preset stack entry air pressure is greater than 10%, which is outside the set deviation range, and the conformity between the stack entry air pressure and the preset stack entry air pressure is low. At this time, the corresponding consistency state quantity of the stack entry air pressure is 0, that is, the stack entry air pressure is not within the normal range.

[0096] S213, determining a consistency state quantity of the air flow rate entering the stack according to the air flow rate entering the stack and in combination with a preset air flow rate entering the stack.

[0097] Among them, this step can be further refined as follows: according to the air flow entering the stack and in combination with the preset air flow entering the stack, based on the third calculation formula, the consistency state quantity of the air flow entering the stack is determined; the third calculation formula is: STma=(Maset-Maact) / Maset, wherein Maact is the air flow entering the stack, Maset is the preset air flow entering the stack, and STma is the consistency state quantity of the air flow entering the stack.

[0098] The preset stack air flow rate may be a design value of the stack air flow rate or an empirical value set based on experience.

[0099] Specifically, when determining the consistency state quantity of the stack air flow, according to the acquired stack air flow and the preset stack air flow, based on the third calculation formula of STma=(Maset-Maact) / Maset, the stack air flow Maact and the preset stack air flow Maset are both known, and after being substituted into the third calculation formula, the consistency state quantity STma of the stack air flow can be obtained. When the calculated consistency state quantity STma of the stack air flow is ≤A, where A is a constant greater than 0 and less than or equal to 20%, illustratively, A=10%, it indicates that the deviation between the actually acquired stack air flow and the preset stack air flow is less than or equal to 10%, which is within the set deviation range, and the conformity between the stack air flow and the preset stack air flow is high. At this time, the corresponding consistency state quantity of the stack air flow is 1, that is, the stack air flow is within the normal range. When the calculated consistency state quantity STma of the stack air flow rate is greater than A, exemplarily A=10%, it indicates that the deviation between the actual stack air flow rate and the preset stack air flow rate is greater than 10%, which is outside the set deviation range, and the conformity between the stack air flow rate and the preset stack air flow rate is low. At this time, the corresponding consistency state quantity of the stack air flow rate is 0, that is, the stack air flow rate is not within the normal range.

[0100] S214. Determine a consistency state quantity of the coolant outlet temperature according to the coolant outlet temperature and a preset coolant outlet temperature.

[0101] Among them, this step can be further refined as follows: according to the coolant outlet temperature, combined with the preset coolant outlet temperature, based on the fourth calculation formula, determine the consistency state quantity of the coolant outlet temperature; the fourth calculation formula is: STtwo=(Twoset-Twoact) / Twoset, wherein Twoact is the coolant outlet temperature, Twoset is the preset coolant outlet temperature, and STtwo is the consistency state quantity of the coolant outlet temperature.

[0102] The preset coolant outlet temperature may be a design value of the coolant outlet temperature or an empirical value set based on experience.

[0103] Specifically, when determining the consistency state quantity of the coolant outlet temperature, according to the obtained coolant outlet temperature and the preset coolant outlet temperature, based on the fourth calculation formula of STtwo=(Twoset-Twoact) / Twoset, the coolant outlet temperature Twoact and the preset coolant outlet temperature Twoset are both known, and after substituting into the third calculation formula, the consistency state quantity STma of the coolant outlet temperature can be obtained. When the calculated consistency state quantity of the coolant outlet temperature STtwo≤A, where A is a constant greater than 0 and less than or equal to 20%, illustratively, A=10%, it indicates that the deviation between the actually obtained coolant outlet temperature and the preset coolant outlet temperature is less than or equal to 10%, which is within the set deviation range, and the conformity between the coolant outlet temperature and the preset coolant outlet temperature is high. At this time, the corresponding consistency state quantity of the coolant outlet temperature is 1, that is, the coolant outlet temperature is within the normal range. When the calculated consistency state quantity STtwo of the coolant outlet temperature is greater than A, exemplarily A=10%, indicating that the deviation between the actual coolant outlet temperature and the preset coolant outlet temperature is greater than 10%, which is outside the set deviation range, and the conformity between the coolant outlet temperature and the preset coolant outlet temperature is low. At this time, the corresponding consistency state quantity of the coolant outlet temperature is 0, that is, the coolant outlet temperature is not within the normal range.

[0104] S215. Determine a consistency state quantity of the coolant inlet temperature according to the coolant inlet temperature and a preset coolant inlet temperature.

[0105] Among them, this step can be further refined as follows: according to the coolant inlet temperature, combined with the preset coolant inlet temperature, based on the fifth calculation formula, determine the consistency state quantity of the coolant inlet temperature; the fifth calculation formula is STtwi = (Twiset-Twiact) / Twiset, wherein Twiact is the coolant inlet temperature, Twiset is the preset coolant inlet temperature, and STtwi is the consistency state quantity of the coolant inlet temperature.

[0106] The preset coolant inlet temperature may be a design value of the coolant inlet temperature or an empirical value set based on experience, etc.

[0107] Specifically, when determining the consistency state quantity of the coolant inlet temperature, according to the obtained coolant inlet temperature and the set preset coolant inlet temperature, based on the fifth calculation formula of STtwi=(Twiset-Twiact) / Twiset, the coolant inlet temperature Twiact and the preset coolant inlet temperature Twiset are both known, and after substituting them into the third calculation formula, the consistency state quantity STtwi of the coolant inlet temperature can be obtained. When the calculated consistency state quantity of the coolant inlet temperature STtwi≤A, where A is a constant greater than 0 and less than or equal to 20%, exemplarily, A=10%, it indicates that the deviation between the actually obtained coolant inlet temperature and the preset coolant inlet temperature is less than or equal to 10%, which is within the set deviation range, and the conformity between the coolant inlet temperature and the preset coolant inlet temperature is high. At this time, the corresponding consistency state quantity of the coolant inlet temperature is 1, that is, the coolant inlet temperature is within the normal range. When the calculated consistency state quantity STtwi of the coolant inlet temperature is greater than A, exemplarily A=10%, indicating that the deviation between the actual coolant inlet temperature and the preset coolant inlet temperature is greater than 10%, which is outside the set deviation range, and the conformity between the coolant inlet temperature and the preset coolant inlet temperature is low. At this time, the corresponding consistency state quantity of the coolant inlet temperature is 0, that is, the coolant inlet temperature is not within the normal range.

[0108] It should be noted that when determining the consistency state quantity of the fuel cell stack, only when the consistency state quantity of the hydrogen pressure entering the stack STphin=1, the consistency state quantity of the air pressure entering the stack STpo=1, the consistency state quantity of the air flow entering the stack STma=1, the consistency state quantity of the coolant outlet temperature STma=1, and the consistency state quantity of the coolant inlet temperature STtwi=1, it indicates that the supply of the fuel cell stack is normal, and the fuel cell stack is in a normal operating state. When any one of them is not 1, that is, when at least one of the consistency state quantities is 0, it indicates that the fuel cell stack is in an abnormal operating state, and the cause of the humidity abnormality will not be diagnosed.

[0109] S216: Determine a voltage difference between a maximum cell voltage and a minimum cell voltage and an average cell voltage according to the cell voltages.

[0110] S217, determining the voltage abnormality state quantity of the battery stack according to the voltage difference and the average single cell voltage, in combination with a preset voltage difference threshold and a preset average single cell voltage threshold.

[0111] S218. Determine the abnormal power generation state quantity of the fuel cell stack according to the pressure difference between the hydrogen pressure entering the stack and the hydrogen pressure leaving the stack in combination with a preset pressure difference threshold.

[0112] S219. Determine the abnormal increase state quantity and the abnormal decrease state quantity of the impedance value of the battery stack according to the high-frequency impedance value.

[0113] S220, determining the abnormal humidity state of the battery stack according to the consistency state quantity, the voltage abnormal state quantity, the power generation abnormal state quantity, the impedance value abnormal increase state quantity and the impedance value abnormal decrease state quantity.

[0114] The technical solution of the embodiment of the present invention determines the consistency state quantity of the hydrogen pressure entering the stack according to the hydrogen pressure entering the stack, combined with the preset hydrogen pressure entering the stack; determines the consistency state quantity of the air pressure entering the stack according to the air pressure entering the stack, combined with the preset air pressure entering the stack; determines the consistency state quantity of the air flow entering the stack according to the air flow entering the stack, combined with the preset air flow entering the stack; determines the consistency state quantity of the coolant outlet temperature according to the coolant outlet temperature, combined with the preset coolant outlet temperature; determines the consistency state quantity of the coolant inlet temperature according to the coolant inlet temperature, combined with the preset coolant inlet temperature. Utilizing the above method, by determining the consistency state quantity corresponding to each of the operating status information related to the operating status of the battery stack, the operating status of the battery stack is accurately determined, providing a basis for the subsequent determination of abnormal humidity diagnosis of the battery stack.

[0115] In another alternative embodiment, Figure 3 This is a flow chart of a third fuel cell stack operating humidity abnormality diagnosis method provided by an embodiment of the present invention. The contents not yet fully described in this embodiment can be referred to the above embodiments, and will not be repeated here. Figure 3 As shown, the method includes:

[0116] S310, obtaining current status information of the battery stack.

[0117] S311. Determine the consistency state quantity of the battery stack according to the current state information of the battery stack.

[0118] S312: Determine a voltage difference between a maximum cell voltage and a minimum cell voltage and an average cell voltage according to the cell voltages.

[0119] S313: When (Vcmax-Vcmin)≥Vcdifset, Vcave≤Vcaveset, and the voltage abnormal state quantity of the battery stack is determined to be 1 for a first preset time.

[0120] Among them, Vcmax-Vcmin is the voltage difference, Vcdifset is the preset voltage difference threshold, Vcave is the average single cell voltage, and Vcaveset is the preset average single cell voltage threshold.

[0121] S314: When (Vcmax-Vcmin)<Vcdifset, or Vcave>Vcaveset, or the duration is less than the first preset time, determine that the voltage abnormal state quantity of the battery stack is 0.

[0122] Specifically, when determining the voltage abnormal state quantity of the battery stack, the voltage abnormal state quantity of the battery stack can be determined to be 1 or 0 according to the relationship between the voltage differential and the preset voltage differential threshold, and the relationship between the average single cell voltage and the preset average single cell voltage threshold. In this embodiment, when it is determined that the voltage differential, that is, Vcmax-Vcmin is greater than or equal to the preset voltage differential threshold Vcdifset, the average single cell voltage Vcave is less than or equal to the preset average single cell voltage threshold Vcaveset, and the above relationship lasts for a first preset time, the first preset time may be less than 3s, indicating that the single cell voltage of the battery stack exceeds the normal single cell voltage threshold range, at this time, the voltage abnormal state quantity of the battery stack is 1, indicating that the voltage differential of the battery stack is too high, the average single cell voltage is too low, and the battery stack voltage is in an abnormal operating range. When it is determined that the voltage difference, i.e., Vcmax-Vcmin, is less than the preset voltage difference threshold, or the average single cell voltage Vcave is greater than the preset average single cell voltage threshold Vcaveset, or the duration of the above relationship is less than the first preset time, it indicates that the operating state of the single cell voltage of the battery stack is within the normal single cell voltage threshold range. At this time, the voltage abnormal state quantity of the battery stack is 0, indicating that the battery stack voltage is in normal operating state.

[0123] S315: When Phdifact≤Phdifset and this continues for a second preset time, determine that the abnormal power generation state quantity of the fuel cell stack is 1.

[0124] Among them, Phdifact is the pressure difference, and Phdifset is the preset pressure difference threshold;

[0125] S316: When Phdifact>Phdifset, or the duration is less than a second preset time, determine that the abnormal power generation state quantity of the fuel cell stack is 0.

[0126] Specifically, when determining the abnormal power generation state quantity of the stack, the abnormal power generation state quantity of the stack can be determined to be 1 or 0 according to the relationship between the pressure differential and the preset pressure differential threshold. In this embodiment, when it is determined that the pressure differential, that is, Phdifact is less than or equal to the preset pressure differential threshold Phdifset, and the above relationship lasts for a second preset time, the second preset time may be less than 3s, indicating that the pressure differential between the inlet pressure and outlet pressure of the stack is less than the normal pressure differential threshold range, and the stack may have abnormalities such as ice blockage, so at this time, the abnormal power generation state quantity of the stack is 1, indicating that the inlet pressure and outlet pressure of the stack are in the abnormal operating range. When the pressure differential is determined, that is, Phdifact is greater than the preset pressure differential threshold Phdifset, or the above relationship lasts for less than the second preset time, it indicates that the operating state of the pressure differential of the stack is within the normal pressure differential threshold range, and the stack does not have abnormal phenomena such as blockage, so at this time, the abnormal power generation state quantity of the stack is 0, indicating that the stack power generation is in a normal operating state.

[0127] S317: Calculate a deviation value of the high-frequency impedance value within a third preset time according to the high-frequency impedance value and a preset high-frequency impedance threshold.

[0128] Among them, the preset high-frequency impedance threshold is the optimal impedance value of the battery stack. The preset high-frequency impedance value is the optimal impedance value of the battery stack when it is working measured at a certain operating frequency and a certain operating current, which can be expressed as Rset, in Ω. Among them, the operating frequency is Feis, in Hz, and the operating current is Ieis, in A. The determination of the preset high-frequency impedance value may include but is not limited to determination through a calibrated three-dimensional chart, etc., the X-axis input of the three-dimensional chart is the battery stack output current, the Y-axis input is the battery stack temperature, and the Z-axis output is the preset high-frequency impedance threshold.

[0129] Specifically, when calculating the deviation value of the high-frequency impedance value of the battery stack, the high-frequency impedance value obtained in real time can be subtracted from the preset high-frequency impedance threshold to obtain the deviation value at that moment. In the same way, the deviation values ​​of the high-frequency impedance value within the third preset time can be calculated, and the maximum deviation value among the deviation values ​​is selected as the deviation value of the high-frequency impedance value of the battery stack.

[0130] S318. Determine the abnormal increase state of the impedance value of the battery stack according to the high-frequency impedance value and the deviation value, in combination with a preset high-frequency impedance threshold and a preset high-frequency impedance value upper deviation threshold.

[0131] Among them, this step can be refined as follows: when Rstack≥Rset, Rstackdif≥Rstackup, and lasts for a fourth preset time, it is determined that the state quantity of the abnormal increase in the impedance value of the battery stack is 1; when Rstack<Rset, or, Rstackdif<Rstackup, or the duration is less than the fourth preset time, it is determined that the state quantity of the abnormal increase in the impedance value of the battery stack is 0; wherein Rstack is the high-frequency impedance value, Rset is the preset high-frequency impedance threshold, Rstackdif is the deviation value, and Rstackup is the preset high-frequency impedance value upper deviation threshold.

[0132] The preset high-frequency impedance value upper deviation threshold is the magnitude of the increase value of the high-frequency impedance within the third preset time.

[0133] Specifically, when determining the abnormal increase state quantity of the impedance value of the battery stack, the abnormal increase state quantity of the impedance value of the battery stack can be determined to be 1 or 0 according to the relationship between the high-frequency impedance value and the preset high-frequency impedance value threshold, and the relationship between the deviation value and the preset high-frequency impedance value upper deviation threshold. In this embodiment, when it is determined that the high-frequency impedance value Rstack is greater than or equal to the preset high-frequency impedance threshold Rset, the deviation value Rstackdif is greater than or equal to the preset high-frequency impedance value upper deviation threshold Rstackup, and the above relationship lasts for a third preset time, the third preset time may be less than 3s, indicating that the high-frequency impedance value of the battery stack exceeds the normal high-frequency impedance value threshold range, and the deviation value exceeds the normal high-frequency impedance value upper deviation threshold range, indicating that the humidity of the battery stack is too dry, and at this time, the abnormal increase state quantity of the impedance value of the battery stack is 1, indicating that the impedance value of the battery stack is in an abnormal operating range. When it is determined that the high-frequency impedance value Rstack is less than the preset high-frequency impedance threshold Rset, or the deviation value Rstackdif is less than the preset high-frequency impedance value upper deviation threshold Rstackup, or the duration of the above relationship is less than the third preset time, it indicates that the high-frequency impedance value of the battery stack is within the normal high-frequency impedance value threshold range. At this time, the abnormal increase state quantity of the impedance value of the battery stack is 0, indicating that the impedance value of the battery stack is in normal operating state.

[0134] S319. Determine the abnormal decrease state of the impedance value of the battery stack according to the high-frequency impedance value and the deviation value, in combination with the preset high-frequency impedance threshold and the preset high-frequency impedance value deviation threshold.

[0135] Among them, this step can be refined as follows: when Rstack<Rset, Rstackdif≤Rstackdo, and it lasts for the fourth preset time, it is determined that the state quantity of the abnormal decrease in the impedance value of the battery stack is 1; when Rstack≥Rset, or, Rstackdif>Rstackdo, or the duration is less than the fourth preset time, it is determined that the state quantity of the abnormal decrease in the impedance value of the battery stack is 0; wherein Rstack is the high-frequency impedance value, Rset is the preset high-frequency impedance threshold, Rstackdif is the deviation value, and Rstackdo is the deviation threshold under the preset high-frequency impedance value.

[0136] The preset high-frequency impedance value lower deviation threshold is the magnitude of the high-frequency impedance reduction value within the fourth preset time.

[0137] Specifically, when determining the abnormal decrease state quantity of the impedance value of the battery stack, the abnormal decrease state quantity of the impedance value of the battery stack can be determined to be 1 or 0 according to the relationship between the high-frequency impedance value and the preset high-frequency impedance value threshold, and the relationship between the deviation value and the preset high-frequency impedance value lower deviation threshold. In this embodiment, when it is determined that the high-frequency impedance value Rstack is less than the preset high-frequency impedance threshold Rset, the deviation value Rstackdif is less than or equal to the preset high-frequency impedance value upper deviation threshold Rstackup, and the above relationship lasts for a fourth preset time, the fourth preset time may be less than 3s, indicating that the high-frequency impedance value of the battery stack does not exceed the normal high-frequency impedance value threshold range, and the deviation value does not exceed the normal high-frequency impedance value lower deviation threshold range, indicating that the humidity of the battery stack is too humid, and at this time, the abnormal decrease state quantity of the impedance value of the battery stack is 1, indicating that the impedance value of the battery stack is in an abnormal operating range. When it is determined that the high-frequency impedance value Rstack is greater than or equal to the preset high-frequency impedance threshold Rset, or the deviation value Rstackdif is greater than the preset high-frequency impedance value upper deviation threshold Rstackup, or the duration of the above relationship is less than the fourth preset time, it indicates that the high-frequency impedance value of the battery stack is within the normal high-frequency impedance value threshold range. At this time, the abnormal decrease state quantity of the impedance value of the battery stack is 0, indicating that the impedance value of the battery stack is in normal operating state.

[0138] S320, when the consistency state quantity is 1, the voltage abnormal state quantity is 1, the power generation abnormal state quantity is 1, and the impedance value abnormal increase state quantity is 1, determine that the humidity abnormal state of the battery stack is a membrane dry fault state.

[0139] Specifically, after determining the consistency state quantity of the battery stack, the voltage abnormal state quantity, the power generation abnormal state quantity, and the impedance value abnormal increase state quantity, when the consistency state quantity of the battery stack is 1, it indicates that the battery stack is in a normal operating state at this time. On this basis, when it is determined that the voltage abnormal state quantity is 1, the power generation abnormal state quantity is 1, and the impedance value abnormal increase state quantity is 1, it can be determined that the membrane dry state quantity of the battery stack STstackdry = 1, that is, the battery stack is in a membrane dry fault state. When the consistency state quantity of the battery stack is 0, or the voltage abnormal state quantity is 0, or the power generation abnormal state quantity is 0, or the impedance value abnormal increase state quantity is 0, the membrane dry state quantity of the battery stack STstackdry = 0 at this time, and the battery stack is in a normal membrane dry state.

[0140] S321. When the consistency state quantity is 1, the voltage abnormal state quantity is 1, the power generation abnormal state quantity is 1, and the impedance value abnormal reduction state quantity is 1, it is determined that the humidity abnormal state of the fuel cell stack is a water flooding fault state.

[0141] Specifically, after determining the consistency state quantity of the battery stack, the voltage abnormal state quantity, the power generation abnormal state quantity, and the impedance value abnormal reduction state quantity, when the consistency state quantity of the battery stack is 1, it indicates that the battery stack is in a normal operating state at this time. On this basis, when it is determined that the voltage abnormal state quantity is 1, the power generation abnormal state quantity is 1, and the impedance value abnormal reduction state quantity is 1, it can be determined that the water flooding state quantity of the battery stack STstackwet = 1, that is, the battery stack is in a water flooding fault state. When the consistency state quantity of the battery stack is 0, or the voltage abnormal state quantity is 0, or the power generation abnormal state quantity is 0, or the impedance value abnormal reduction state quantity is 0, the membrane dry state quantity of the battery stack STstackwet = 0 at this time, and the battery stack is in a normal state of water flooding.

[0142] The technical solution of the embodiment of the present invention realizes the accurate determination of humidity anomalies of the fuel cell stack, greatly reduces the risk of misjudgment, ensures the stable operation of the stack, and improves the service life of the stack.

[0143] It should be understood that the various forms of processes shown above can be used to reorder, add or delete steps. For example, the steps described in the present invention can be executed in parallel, sequentially or in different orders, as long as the desired results of the technical solution of the present invention can be achieved, and this document does not limit this.

[0144] The above specific implementations do not constitute a limitation on the protection scope of the present invention. It should be understood by those skilled in the art that various modifications, combinations, sub-combinations and substitutions can be made according to design requirements and other factors. Any modification, equivalent substitution and improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for diagnosing abnormal humidity during operation of a fuel cell stack, characterized in that: Used in vehicles, including: Acquire current status information of the fuel cell stack; the current status information of the fuel cell stack includes at least the single cell voltage of the fuel cell stack, the hydrogen pressure entering the stack, the hydrogen pressure leaving the stack, and the real-time high-frequency impedance of the fuel cell stack; Determining a consistency state quantity of the battery stack according to the current state information of the battery stack; Determine a voltage difference between a maximum cell voltage and a minimum cell voltage and an average cell voltage according to the cell voltages; Determine the voltage abnormal state quantity of the battery stack according to the voltage difference and the average single cell voltage, in combination with a preset voltage difference threshold and a preset average single cell voltage threshold; Determining the abnormal power generation state quantity of the fuel cell stack according to the pressure difference between the hydrogen gas inlet pressure and the hydrogen gas outlet pressure in combination with a preset pressure difference threshold; Determining, according to the high-frequency impedance value, a state quantity of abnormally increased impedance value and a state quantity of abnormally decreased impedance value of the battery stack; The humidity abnormal state of the battery stack is determined based on the consistency state quantity, the voltage abnormal state quantity, the power generation abnormal state quantity, the impedance value abnormal increase state quantity and the impedance value abnormal decrease state quantity; the humidity abnormal state of the battery stack includes a membrane dry fault state and a water flooding fault state.

2. The diagnostic method according to claim 1, characterized in that The current status information also includes the stack air pressure, stack air flow, coolant outlet temperature and coolant inlet temperature; Determining the consistency state quantity of the battery stack according to the current state information of the battery stack includes: Determining a consistency state quantity of the hydrogen pressure entering the stack according to the hydrogen pressure entering the stack and in combination with a preset hydrogen pressure entering the stack; Determining a consistency state quantity of the stack-entering air pressure according to the stack-entering air pressure and in combination with a preset stack-entering air pressure; Determining a consistency state quantity of the stack-entering air flow rate according to the stack-entering air flow rate and in combination with a preset stack-entering air flow rate; Determining a consistency state quantity of the coolant outlet temperature according to the coolant outlet temperature and in combination with a preset coolant outlet temperature; According to the coolant inlet temperature and in combination with a preset coolant inlet temperature, a consistency state quantity of the coolant inlet temperature is determined.

3. The diagnostic method according to claim 2, characterized in that According to the hydrogen pressure entering the stack, in combination with a preset hydrogen pressure entering the stack, a consistency state quantity of the hydrogen pressure entering the stack is determined, including: According to the hydrogen pressure entering the stack, combined with the preset hydrogen pressure entering the stack, based on the first calculation formula, the consistency state quantity of the hydrogen pressure entering the stack is determined; the first calculation formula is: STphin = (Phinset-Phinact) / Phinset, wherein Phinact is the hydrogen pressure entering the stack, Phinset is the preset hydrogen pressure entering the stack, and STphin is the consistency state quantity of the hydrogen pressure entering the stack; Determining the consistency state quantity of the stack-entering air pressure according to the stack-entering air pressure in combination with a preset stack-entering air pressure includes: According to the stack-entering air pressure and in combination with the preset stack-entering air pressure, a consistency state quantity of the stack-entering air pressure is determined based on a second calculation formula; the second calculation formula is: STpo=(Poset-Poact) / Poset, wherein Poact is the stack-entering air pressure, Poset is the preset stack-entering air pressure, and STpo is the consistency state quantity of the stack-entering air pressure; According to the stack-inlet air flow rate, combined with a preset stack-inlet air flow rate, a consistency state quantity of the stack-inlet air flow rate is determined, including: According to the stack-entering air flow rate, combined with the preset stack-entering air flow rate, based on a third calculation formula, the consistency state quantity of the stack-entering air flow rate is determined; the third calculation formula is: STma=(Maset-Maact) / Maset, wherein Maact is the stack-entering air flow rate, Maset is the preset stack-entering air flow rate, and STma is the consistency state quantity of the stack-entering air flow rate; According to the coolant outlet temperature, combined with a preset coolant outlet temperature, a consistency state quantity of the coolant outlet temperature is determined, including: According to the coolant outlet temperature, combined with the preset coolant outlet temperature, based on the fourth calculation formula, the consistency state quantity of the coolant outlet temperature is determined; the fourth calculation formula is: STtwo=(Twoset-Twoact) / Twoset, wherein Twoact is the coolant outlet temperature, Twoset is the preset coolant outlet temperature, and STtwo is the consistency state quantity of the coolant outlet temperature; Determining the consistency state quantity of the coolant inlet temperature according to the coolant inlet temperature and in combination with a preset coolant inlet temperature includes: According to the coolant inlet temperature and the preset coolant inlet temperature, the consistency state quantity of the coolant inlet temperature is determined based on the fifth calculation formula; the fifth calculation formula is STtwi = (Twiset-Twiact) / Twiset, wherein Twiact is the coolant inlet temperature, Twiset is the preset coolant inlet temperature, and STtwi is the consistency state quantity of the coolant inlet temperature.

4. The diagnostic method according to claim 3, characterized in that: When STphin≤A, the consistency state quantity of the hydrogen pressure entering the stack is 1; when STphin>A, the consistency state quantity of the hydrogen pressure entering the stack is 0; and / or, When STpo≤A, the consistency state quantity of the air pressure entering the stack is 1; when STpo>A, the consistency state quantity of the air pressure entering the stack is 0; and / or, When STma≤A, the consistency state quantity of the air flow entering the stack is 1; when STma>A, the consistency state quantity of the air flow entering the stack is 0; and / or, When STtwo≤A, the consistency state quantity of the coolant outlet temperature is 1; when STtwo>A, the consistency state quantity of the coolant outlet temperature is 0; and / or, When STtwi≤A, the consistency state quantity of the coolant inlet temperature is 1; when STtwi>A, the consistency state quantity of the coolant inlet temperature is 0; Wherein, A is a constant, 0<A≤20%.

5. The diagnostic method according to claim 1, characterized in that: Determining the voltage abnormal state quantity of the battery stack according to the voltage difference and the average battery voltage, in combination with a preset voltage difference threshold and a preset average battery voltage threshold, includes: When (Vcmax-Vcmin)≥Vcdifset, Vcave≤Vcaveset, and the voltage abnormal state quantity of the battery stack is determined to be 1 for a first preset time; When (Vcmax-Vcmin)<Vcdifset, or Vcave>Vcaveset, or the duration is less than the first preset time, the voltage abnormal state quantity of the battery stack is determined to be 0; wherein Vcmax-Vcmin is the voltage difference, Vcdifset is the preset voltage difference threshold, Vcave is the average single cell voltage, and Vcaveset is the preset average single cell voltage threshold.

6. The diagnostic method according to claim 1, characterized in that: Determining the abnormal power generation state quantity of the fuel cell stack according to the pressure difference between the hydrogen pressure entering the stack and the hydrogen pressure leaving the stack in combination with a preset pressure difference threshold includes: When Phdifact≤Phdifset and the condition lasts for a second preset time, determining that the abnormal power generation state quantity of the battery stack is 1; When Phdifact>Phdifset, or the duration is less than the second preset time, it is determined that the abnormal power generation state quantity of the fuel cell stack is 0; wherein Phdifact is the pressure difference, and Phdifset is the preset pressure difference threshold.

7. The diagnostic method according to claim 1, characterized in that: Determining, according to the high-frequency impedance value, a state quantity of abnormally increased impedance value and a state quantity of abnormally decreased impedance value of the battery stack, including: Calculating a deviation value of the high-frequency impedance value within a third preset time according to the high-frequency impedance value and in combination with a preset high-frequency impedance threshold; Determine the abnormal increase state quantity of the impedance value of the battery stack according to the high-frequency impedance value and the deviation value, in combination with the preset high-frequency impedance threshold and the preset high-frequency impedance value upper deviation threshold; According to the high-frequency impedance value and the deviation value, combined with the preset high-frequency impedance threshold and the preset high-frequency impedance value lower deviation threshold, the abnormal reduction state quantity of the impedance value of the battery stack is determined.

8. The diagnostic method according to claim 7, characterized in that: According to the high-frequency impedance value and the deviation value, in combination with the preset high-frequency impedance threshold and the preset high-frequency impedance value upper deviation threshold, determining the abnormal increase state quantity of the impedance value of the battery stack includes: When Rstack≥Rset, Rstackdif≥Rstackup, and the condition lasts for a fourth preset time, determining that the abnormally increased state quantity of the impedance value of the stack is 1; When Rstack<Rset, or Rstackdif<Rstackup, or the duration is less than the fourth preset time, it is determined that the abnormal increase state of the impedance value of the fuel cell stack is 0; wherein Rstack is the high-frequency impedance value, Rset is the preset high-frequency impedance threshold, Rstackdif is the deviation value, and Rstackup is the upper deviation threshold of the preset high-frequency impedance value.

9. The diagnostic method according to claim 7, characterized in that: According to the high-frequency impedance value and the deviation value, in combination with the preset high-frequency impedance threshold and the preset high-frequency impedance value lower deviation threshold, determining the abnormal decrease state quantity of the impedance value of the battery stack includes: When Rstack<Rset, Rstackdif≤Rstackdo, and the condition lasts for a fourth preset time, determining that the abnormal decrease state value of the impedance value of the stack is 1; When Rstack≥Rset, or Rstackdif>Rstackdo, or the duration is less than the fourth preset time, it is determined that the abnormal decrease state of the impedance value of the fuel cell stack is 0; wherein Rstack is the high-frequency impedance value, Rset is the preset high-frequency impedance threshold, Rstackdif is the deviation value, and Rstackdo is the deviation threshold below the preset high-frequency impedance value.

10. The diagnostic method according to claim 1, characterized in that Determining the abnormal humidity state of the battery stack according to the consistency state quantity, the abnormal voltage state quantity, the abnormal power generation state quantity, the abnormal impedance value increase state quantity and the abnormal impedance value decrease state quantity includes: When the consistency state quantity is 1, the voltage abnormal state quantity is 1, the power generation abnormal state quantity is 1, and the impedance value abnormal increase state quantity is 1, the humidity abnormal state of the battery stack is determined to be the membrane dry fault state; When the consistency state quantity is 1, the voltage abnormal state quantity is 1, the power generation abnormal state quantity is 1, and the impedance value abnormal reduction state quantity is 1, the humidity abnormal state of the fuel cell stack is determined to be the water flooding fault state.

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