Diagnostic method for diagnosing the state of a fuel cell driven energy supply system

Abstract

The present invention relates to a diagnostic method (100) for diagnosing the condition of an energy supply system (200) including multiple fuel cell systems (201, 203).

Description

Technical Field

[0001] The invention relates to a diagnostic method for diagnosing the condition of an energy supply system, an energy supply system, a vehicle, and a program product, according to the appended claims. Background Technology

[0002] Polymer electrolyte membrane (PEM) fuel cell systems use oxygen to convert hydrogen into electricity, while also generating waste heat and water.

[0003] Here, the conversion of hydrogen means that hydrogen molecules are consumed or removed on the anode side.

[0004] A PEM fuel cell here includes an anode supplied with hydrogen, a cathode supplied with air, and a polymer electrolyte membrane located between the two.

[0005] Multiple such individual fuel cells are stacked together to form a fuel cell stack, thereby increasing the generated voltage.

[0006] Inside such a fuel cell stack (“Stack”), there are supply channels that supply hydrogen and air to individual cells, or remove depleted humid air and depleted anode exhaust gas.

[0007] Fresh hydrogen is supplied via a hydrogen metering valve, which can be implemented as a proportional valve. A control strategy is set to adjust the gas pressure within the anode path, measured at a defined location by a pressure sensor, to a defined target pressure based on the system operating point, using the hydrogen metering valve.

[0008] The reasons for replenishing fresh hydrogen may include the consumption of hydrogen through electrochemical conversion, and other losses of gas molecules from the anode space, such as due to prolonged opening of the flushing valve.

[0009] The pressure drop is generated relative to the high-pressure hydrogen regulator located further upstream, based on the hydrogen mass flow rate upstream of the hydrogen metering valve. Summary of the Invention

[0010] Within the framework of the present invention, a diagnostic method, an energy supply system, a vehicle, and a program product are proposed. Further features and details of the invention are given in the corresponding dependent claims, description, and drawings. Herein, the features and details described in conjunction with the diagnostic method according to the invention also apply to the energy supply system according to the invention, the vehicle according to the invention, or the program product according to the invention, and vice versa, so that the disclosure of each aspect of the invention can always be cross-referenced.

[0011] The present invention is particularly useful for providing a robust fuel cell system.

[0012] Therefore, according to the first aspect of the present invention, a diagnostic method for diagnosing the state of an energy supply system comprising a number of fuel cell systems, i.e., one fuel cell system or multiple fuel cell systems.

[0013] The proposed diagnostic method includes: measuring the supply pressure in the supply line between multiple high-pressure tanks and multiple fuel cell systems, downstream of the high-pressure regulator and upstream of each shut-off valve of the multiple fuel cell systems in the flow direction; measuring the specific pressure for each fuel cell system in the consumer region, downstream of the shut-off valve for cutting off the hydrogen supply to each fuel cell system and upstream of the metering valve for metering hydrogen into the anode subsystem of each fuel cell system; determining the specific mass flow rate for each fuel cell system as a function of the supply pressure and the specific pressures; and outputting a fault report if the specific mass flow rates differ from each other by a diagnostic value greater than a predetermined threshold when the fuel cell systems of the multiple fuel cell systems are at the same operating point.

[0014] The principle upon which this invention is based is to assess the pressure change process in the intermediate-pressure region (i.e., the region between the high-pressure region of the tank system and the low-pressure region of the fuel cell stack) in order to infer the specific mass flow rate supplied to each fuel cell system.

[0015] Since the mass flow rates supplied to different fuel cell systems in the energy supply system should be comparable, and especially equal, when they are at the same operating point, a deviation in the mass flow rate can be used to assume that one of the fuel cell systems, especially the one supplied with a larger mass flow rate, is faulty. Accordingly, a fault report can be generated in this case.

[0016] The diagnostic method may be configured to also include a function that outputs a specific mass flow rate to at least one receiver.

[0017] By outputting a specific mass flow rate to a receiver function, such as in a vehicle or controller, the receiver function can be specifically configured for the state of multiple fuel cell systems.

[0018] It can also be configured to measure the supply pressure in the region upstream of the distributor, which distributes the hydrogen flowing through the supply line to the individual fuel cell systems of multiple fuel cell systems.

[0019] The supply pressure measured in the region upstream of the distributor constitutes a common reference value for all fuel cell systems, which distribute hydrogen flowing through the supply line to the individual fuel cell systems of the plurality of fuel cell systems, and this reference value varies identically for all fuel cell systems. Accordingly, the supply pressure measured in the region upstream of the distributor minimizes the variance in determining diagnostic values ​​and maximizes the reliability of the proposed diagnostic method, which distributes hydrogen flowing through the supply line to the individual fuel cell systems of the plurality of fuel cell systems.

[0020] It can also be configured to consider specific liquid resistance in each consumer region when determining each specific mass flow rate.

[0021] The specific liquid resistance in each consumer region is taken into account, so that the specific mass pressures are comparable even when the line geometry leading to each fuel cell system is different.

[0022] It can also be configured to determine specific liquid resistances through flow simulation or by measurement using mass flow sensors integrated in or connected downstream of each consumer region.

[0023] A specific liquid resistance can be calculated once for the corresponding configuration of the energy supply system, and then used as a predetermined value (e.g., as a coefficient) in the use of the energy supply system to perform the proposed diagnostic method.

[0024] It can also be configured to consider the liquid resistance of the supply line in addition to the specific liquid resistance in each consumer area when determining each specific mass flow rate.

[0025] Since the liquid resistance of the supply line also affects the mass flow rate in each consumer region, the liquid resistance of the supply line can also be calculated in advance for the corresponding configuration of the energy supply system, and then used as a predetermined value (e.g., as a coefficient) in the use of the energy supply system to perform the proposed diagnostic method.

[0026] According to the second aspect, the present invention relates to an energy supply system for supplying electrical energy to a consumer.

[0027] The proposed energy supply system includes: a tank system comprising multiple high-pressure tanks and a pressure reducer arranged in a central supply line; multiple fuel cell systems, each fluidly connected to the supply line via a specific consumer line; a supply pressure sensor arranged in the flow direction downstream of the high-pressure regulator and upstream of each shut-off valve of the multiple fuel cell systems in the supply line between the multiple high-pressure tanks and the multiple fuel cell systems; multiple specific pressure sensors arranged in the consumer region downstream of a shut-off valve for cutting off hydrogen supply to each fuel cell system and upstream of a metering valve for metering hydrogen into the anode subsystem of each fuel cell system; and a computing unit configured in one possible configuration for implementing the proposed diagnostic method.

[0028] The proposed energy supply system is based on using, for example, multiple fuel cell systems operating in parallel in order to maximize the power of the energy supply system.

[0029] Accordingly, the energy supply system can be configured to include a first fuel cell system and a second fuel cell system.

[0030] The proposed energy supply system configuration with two fuel cell systems has proven particularly suitable for driving vehicles, as it creates a good trade-off between power and space requirements. Of course, the proposed energy supply system could also be considered with one or more fuel cell systems.

[0031] Alternatively, the computing unit can be configured as a central server, which communicates with the controller of the energy supply system.

[0032] By using a central server as the computing unit, the server can monitor the status changes of the corresponding energy supply system, thereby automatically planning the maintenance or repair of the energy supply system, for example, when outputting fault reports. Here, a single server can serve as the computing unit for multiple energy supply systems.

[0033] According to a third aspect, the present invention relates to a vehicle, wherein the vehicle includes one possible configuration of the proposed energy supply system.

[0034] According to a fourth aspect, the present invention relates to a program product, wherein the program product includes a program code means that configures a computing unit for implementing a possible configuration of the proposed diagnostic method when the program product is implemented on the computing unit.

[0035] The advantages of the diagnostic method for diagnosing the state of an energy supply system according to the first aspect of the invention also apply to the energy supply system for supplying electrical energy to a consumer according to the second aspect of the invention, the vehicle according to the third aspect of the invention, and the program product according to the fourth aspect of the invention.

[0036] Other advantages, features, and details of the invention are set forth below with reference to the accompanying drawings, in which embodiments of the invention are described in detail. Herein, the features mentioned in the claims and description may be important to the invention individually or in any combination. Attached Figure Description

[0037] The attached diagram shows Figure 1 One possible configuration of the proposed diagnostic method, Figure 2 A schematic diagram of one possible configuration of the proposed energy supply system. Figure 3 One possible configuration of the proposed vehicle. Detailed Implementation

[0038] exist Figure 1 The diagram shows the diagnostic criteria. Figure 2 A diagnostic method 100 for the state of an energy supply system 200, which includes multiple fuel cell systems 201 and 203.

[0039] The diagnostic method 100 includes a first measurement step 101 in which the supply pressure is measured in the flow direction downstream of the high-pressure regulator 209 and upstream of each shut-off valve 211, 213 of the multiple fuel cell systems 201, 203 in the supply line 205 between the multiple high-pressure tanks 207 and the multiple fuel cell systems 201, 203.

[0040] In addition, the diagnostic method 100 includes a second measurement step 103 in which a specific pressure for each fuel cell system 201, 203 is measured in the consumer regions 215, 217, downstream of shut-off valves 211, 213 for cutting off the hydrogen supply to each fuel cell system 201, 203 and upstream of metering valves 219, 221 for metering hydrogen into the anode subsystem of each fuel cell system 201, 203.

[0041] In addition, the diagnostic method 100 includes a determination step 105 in which a specific mass flow rate for each fuel cell system 201, 203 is calculated as a function of the supply pressure and each specific pressure, for example according to formulas (1) to (4).

[0042] In addition, the diagnostic method 100 includes an output step 107, in which a fault report is output if, when the fuel cell systems 201 and 203 are at the same operating point, the difference between each specific mass flow rate is greater than a predetermined threshold diagnostic value.

[0043] exist Figure 2 The diagram shows an energy supply system 200.

[0044] The energy supply system 200 includes a first fuel cell system 201 and a second fuel cell system 203, as well as a supply line 205, a high-pressure regulator 209, and shut-off valves 211 and 213 between a plurality of high-pressure tanks 207 and the fuel cell systems 201 and 203. The shut-off valves can cut off the mass flow rate of hydrogen to the fuel cell systems 201 and 203.

[0045] The first fuel cell system 201 is supplied with hydrogen by a first metering valve 219 arranged in the first consumer region 215, and the second fuel cell system 203 is supplied with hydrogen by a second metering valve 221 arranged in the second consumer region 217.

[0046] The locations marked with P represent the corresponding pressure, and the locations marked with R represent the corresponding drag coefficient of the line geometry. Here, R0, R1, R2, P0, P1, and P2 are known, while P... o’ , 0、 1. 2 is unknown. Accordingly, there are 4 unknowns for the 4 equations, therefore there exists a solvable system.

[0047] After calculating the volumetric flow rate, it can eventually be converted to the mass flow rate using density.

[0048] The relationships shown can be stored in the data model of the computing unit provided according to the invention, so that the corresponding mass flow rate can be easily determined based on the pressure measurement.

[0049] In order to perform the calculation according to diagnostic method 100, the following relationship applies: (1) (2) (3) (4) For energy supply systems with specific line geometry, such as when the pipes or pipe fittings between individual fuel cell systems differ from each other, such differences can be mathematically considered or compensated for by equations (5), (6) and (7).

[0050] (5) and (6) (7) Here, equation (5) applies to line geometry with pipes, and equation (6) applies to line geometry with pipe fittings, which may include, for example, valves, heat exchangers and / or pipes.

[0051] Here, "ξ" represents the resistance coefficient of the pipe fitting (such as a heat exchanger, valve, or pipe).

[0052] Here, through the item Determine the resistance coefficient of the pipeline.

[0053] The relationship is illustrated here, for example, with a configuration having two fuel cell systems. The method can be used similarly for n systems.

[0054] exist Figure 3 The image shows vehicle 300. Vehicle 300 includes, according to... Figure 2 Energy supply system 200.

Claims

1. A diagnostic method (100) for diagnosing the condition of an energy supply system (200), the energy supply system comprising a plurality of fuel cell systems (201, 203). in, The diagnostic method (100) includes: In the supply line (205) between the multiple high-pressure tanks (207) and the multiple fuel cell systems (201, 203), the supply pressure (101) is measured in the flow direction downstream of the high-pressure regulator (209) and upstream of each shut-off valve (211, 213) of the multiple fuel cell systems (201, 203); In each of the consumer regions (215, 217), downstream of the shut-off valves (211, 213) for cutting off the hydrogen supply to each of the fuel cell systems (201, 203) and upstream of the metering valves (219, 221) for metering hydrogen into the anode subsystems of each of the fuel cell systems (201, 203), a specific pressure for each of the plurality of fuel cell systems (201, 203) is measured (103). As a function of the supply pressure and each specific pressure, a specific mass flow rate for each of the plurality of fuel cell systems (201, 203) is determined (105); If, when the individual fuel cell systems (201, 203) of the plurality of fuel cell systems (201, 203) are at the same operating point, the individual specific mass flow rates differ from each other by a diagnostic value greater than a predetermined threshold, then a fault report (107) is output.

2. The diagnostic method (100) according to claim 1. Its features are, The diagnostic method also includes: The function outputs the specific quality flow rate to at least one receiver.

3. The diagnostic method (100) according to claim 1 or 2. Its features are, The supply pressure is measured in the region upstream of the distributor, which distributes hydrogen flowing through the supply line (205) to the individual fuel cell systems (201, 203) of the plurality of fuel cell systems (201, 203).

4. The diagnostic method (100) according to any one of the preceding claims. Its features are, When determining each specific mass flow rate, the specific liquid resistance in each consumer region (215, 217) is taken into account.

5. The diagnostic method (100) according to claim 4. Its features are, Each specific liquid resistance is determined by flow simulation or by measurement using a mass flow sensor integrated in or connected downstream of each consumer region (215, 217).

6. The diagnostic method (100) according to claim 4 or 5. Its features are, When determining each specific mass flow rate, in addition to considering the specific liquid resistance in each consumer area, the liquid resistance of the supply line (205) is also considered.

7. An energy supply system (200) for supplying electrical energy to a consumer. in, The energy supply system (200) includes: The tank system includes multiple high-pressure tanks (207) and pressure reducers (209) arranged in a central supply line (205). Multiple fuel cell systems (201, 203) are fluidly connected to the supply line (205) via specific consumer lines; A supply pressure sensor is provided, which is arranged in the flow direction in the supply line (205) between the plurality of high-pressure tanks (207) and the plurality of fuel cell systems (201, 203) downstream of the high-pressure regulator (209) and upstream of each shut-off valve (211, 213) of the plurality of fuel cell systems (201, 203). Multiple specific pressure sensors are arranged in the consumer regions (215, 217) downstream of shut-off valves (211, 213) for cutting off the hydrogen supply to the respective fuel cell systems (201, 203) and upstream of metering valves (219, 221) in the anode subsystems of the respective fuel cell systems (201, 203). A computing unit configured to implement the diagnostic method (100) according to any one of claims 1 to 5.

8. The energy supply system (200) according to claim 7. Its features are, The energy supply system (200) includes a first fuel cell system (201) and a second fuel cell system (203).

9. The energy supply system (200) according to claim 7 or 8. Its features are, The computing unit is a central server, which is communicatively connected to the controller of the energy supply system (200).

10. A vehicle (300). in, The vehicle (300) includes an energy supply system (200) according to claim 8 or 9.

11. A program product, in, The program product includes a program code device that configures a computing unit to perform the diagnostic method (100) according to any one of claims 1 to 6 when the program product is implemented on the computing unit.

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