Method, control device and computer program for determining moisture content in fuel cell system, and gas mixture analysis device and fuel cell system

Abstract

The invention relates to a method, a control device (160) and a computer program for determining a moisture content in a gas mixture present in an anode line system (130) of a fuel cell system (100) as well as to a gas mixture analysis device (180) and to a fuel cell system (100). An anode line system (130) fluidly connects the hydrogen injector (122) to an anode of the fuel cell system (100) and has at least one thermal conductivity sensor (131, 133) which is designed to generate a gas signal representative of a thermal conductivity in the gas mixture. The method according to the invention comprises: receiving a first gas signal from the at least one thermal conductivity sensor (131, 133) at a first time (t1); sending a hydrogen delivery signal indicative of a predetermined hydrogen delivery rate to the hydrogen injector (122) at a second time (t2); receiving a second gas signal from the at least one thermal conductivity sensor (131, 133) at a fourth time (t4) at which hydrogen is delivered to the anode piping system (130); and determining a moisture content in the anode piping system (130) based at least in part on the first gas signal, the second gas signal, and a predetermined hydrogen delivery rate.

Description

[0001] The present invention relates to a method, control device, and computer program for determining the moisture content in a gas mixture in a fuel cell system, particularly in the anode line system of the fuel cell system, by means of a thermal conductivity sensor, as well as a gas mixture analysis device and a fuel cell system.

[0002] Fuel cell systems utilize hydrogen from a hydrogen tank for operation. It is known to use thermal conductivity sensors to measure the hydrogen concentration in a fuel cell system. These sensors generate a gas signal representing the sum of the moisture content, nitrogen concentration, and hydrogen concentration at a corresponding measurement point within the fuel cell system. Existing thermal conductivity sensors are based on the principle of thermal conductivity measurement. In this case, by determining the overall thermal conductivity of the gas mixture, the concentration of its individual gas components can be deduced. For example, the hydrogen concentration in the gas mixture can be particularly deduced in this case because the thermal conductivity of hydrogen is significantly higher than that of many other gas components.

[0003] However, known thermal conductivity sensors exhibit cross-sensitivity to water (vapor), causing the gaseous signal from the sensor to indicate the sum of moisture content and hydrogen concentration (and nitrogen concentration, if present in the gas mixture). Therefore, humidity present in the fuel cell system distorts the measurement of hydrogen concentration.

[0004] In the prior art, for example, DE 10 2016 210 518 A1, US 2019 / 0 288 314 A1, DE10 2020 211 893 A1, DE 10 2020 117 820 A1 and US 2006 / 0 169 024 A1 are known.

[0005] The main objective of this invention is to determine the moisture content in the anode piping system of a fuel cell system as accurately as possible.

[0006] This objective is achieved by the method according to independent claim 1, the control device according to claim 8, the gas mixture analysis device according to claim 11, the fuel cell system according to claim 12, the computer program according to claim 14, and the computer program product according to claim 15. Advantageous designs are given in the dependent claims.

[0007] This invention is primarily based on the following concept: utilizing the cross-sensitivity of a thermal conductivity sensor arranged in the anode piping system of a fuel cell system to the humidity in the anode piping system, i.e., determining the moisture content in the gas mixture present in the anode piping system based on the gas signal from the thermal conductivity sensor. Furthermore, this invention is primarily based on the following concept: given a known moisture content, compensating for the gas signal from the thermal conductivity sensor designed to detect the thermal conductivity of the gas mixture with this moisture content, thereby achieving a more accurate determination of the hydrogen concentration in the gas mixture.

[0008] Here, the invention is primarily based on: a first gas signal representing the thermal conductivity of the gas mixture present in the anode piping system before the injection of fresh hydrogen, and a second gas signal representing the thermal conductivity of the gas mixture present in the anode piping system during or after the injection of fresh hydrogen. The first and second gas signals can either be generated at two different times using thermal conductivity sensors at the same measurement point, or they can be generated substantially simultaneously using two thermal conductivity sensors at two different measurement points, one of which is located where fresh hydrogen is being or has been delivered, while the other is located where fresh hydrogen is (not yet) being delivered.

[0009] Therefore, according to a first aspect of the invention, a method for determining the moisture content in a gas mixture present in an anode line system of a fuel cell system is disclosed. The anode line system fluidly connects a hydrogen injector to the anode of the fuel cell system, the hydrogen injector being designed to deliver hydrogen from a hydrogen tank to the anode line system. The anode line system has at least one thermal conductivity sensor, which is designed to generate a gas signal representing the thermal conductivity of the gas mixture in the anode line system. The method according to the invention includes: receiving a first gas signal from the at least one thermal conductivity sensor at a first moment, and sending a hydrogen delivery signal to the hydrogen injector at a second moment. The hydrogen delivery signal causes the hydrogen injector to deliver hydrogen from the hydrogen tank to the anode line system at a predetermined hydrogen delivery rate between the second and third moments. The method according to the invention further includes: at a fourth moment when hydrogen from a hydrogen tank is being or has been supplied to the anode pipeline system, receiving a second gas signal from the at least one thermal conductivity sensor, and determining the moisture content in the anode pipeline system based at least in part on the first gas signal, at least in part on the second gas signal and at least in part on a predetermined hydrogen supply rate.

[0010] According to the present invention, the moisture content in a gas mixture can be determined when processing a first gas signal, a second gas signal, and a predetermined hydrogen delivery rate.

[0011] Preferably, the first moment is earlier than the second moment, or the same as the second moment.

[0012] In an advantageous design of the method of the present invention, the fourth time point is later than the second time point and earlier than or the same as the third time point.

[0013] In a preferred embodiment of the method of the present invention, the second gas signal represents the thermal conductivity of the gas mixture located immediately downstream of the hydrogen injector. Specifically, the second gas signal can represent the sum of the moisture content, hydrogen concentration, and nitrogen concentration in the gas mixture within the anode piping system.

[0014] In another preferred embodiment of the method of the present invention, the first gas signal represents the thermal conductivity of the gas mixture at a location downstream of the anode. Specifically, the first gas signal may represent the sum of the moisture content, hydrogen concentration, and nitrogen concentration in the gas mixture within the anode piping system.

[0015] In an advantageous embodiment, the method of the invention further includes: receiving a third gas signal from the at least one thermal conductivity sensor at a fifth time later than the third and fourth times, and determining a hydrogen concentration based at least in part on the determined moisture content and at least in part on the third gas signal received at the fifth time.

[0016] In a particularly preferred embodiment of the method of the invention, the anode piping system includes a reflux pump designed to circulate the gas mixture flowing through the anode piping system in a loop at a predetermined circulation rate, thereby repeatedly delivering the gas mixture to the anode. The method of the invention further includes determining a rate ratio between the circulation rate of the reflux pump and the hydrogen delivery rate of the hydrogen injector. Here, the determination of the moisture content in the anode piping system is also based at least in part on the determined rate ratio.

[0017] According to another aspect of the invention, a control device is disclosed, which is designed to perform the steps of the method of the invention.

[0018] In an advantageous design, the control device according to the invention comprises: a first control device section for performing the step of receiving a first gas signal and a second gas signal from the at least one thermal conductivity sensor; a second control device section for performing the step of sending a hydrogen delivery signal to a hydrogen injector; and a third control device section for performing the step of determining the moisture content in the anode piping system.

[0019] In another advantageous design, the control device according to the invention further comprises a fourth control device section for performing the step of determining the hydrogen concentration.

[0020] According to another aspect of the invention, a gas mixture analysis device for a fuel cell system is disclosed. The gas mixture analysis device according to the invention comprises: at least one thermal conductivity sensor designed to generate a gas signal; and a control device according to the invention.

[0021] In a preferred design of the gas mixture analysis device of the present invention, a first thermal conductivity sensor is designed to generate a second gas signal, the second gas signal representing the thermal conductivity of the gas mixture present in the anode pipeline system of the fuel cell system downstream of the hydrogen injector, and a second thermal conductivity sensor is designed to generate a first gas signal, the first gas signal representing the thermal conductivity of the gas mixture present in the anode pipeline system of the fuel cell system downstream of the anode and upstream of the hydrogen injector.

[0022] According to another aspect of the invention, a fuel cell system is disclosed, comprising: an anode; an anode pipeline system that fluidly connects a hydrogen injector to the anode, the hydrogen injector being designed to deliver hydrogen from a hydrogen tank to the anode pipeline system; and a gas mixture analysis device according to the invention.

[0023] According to another aspect of the invention, a computer program is disclosed that includes instructions, which, when executed by a computing unit, cause the computing unit to perform the method according to the invention.

[0024] According to another aspect of the invention, a computer-readable medium is disclosed on which a computer program according to the invention is stored.

[0025] Further advantages and features of the invention will be apparent to those skilled in the art by applying the teachings set forth herein and by examining the accompanying single drawing, wherein: Figure 1 A schematic diagram of the present invention's fuel cell system for use in a vehicle is shown. Figure 2 An exemplary diagram is shown, in which the following is plotted: Figure 1 An exemplary time-varying curve of the gas signal from the thermal conductivity sensor of the fuel cell system, and Figure 3 It shows the method for determining the presence of Figure 1 An exemplary flowchart of the method of the present invention for reducing the moisture content in the gas mixture in the anode line system of a fuel cell system.

[0026] Within the scope of this disclosure, the term "gas mixture" describes a mixture of hydrogen and other gaseous components (e.g., moisture in the form of water vapor and / or inert gases (e.g., argon), or other gases (e.g., nitrogen)). In particular, in the anode line system of a fuel cell system, the term "gas mixture" describes a mixture of components such as hydrogen, water (vapor), and nitrogen.

[0027] Within the scope of this disclosure, the term "signal" describes raw data converted into a form suitable for data transmission via a selected transmission medium. This can be analog or digital, where the data is first sampled and converted into discrete (typically binary-encoded) values, which are then transmitted through the medium as current pulses or voltages of varying magnitudes. Furthermore, within the scope of this disclosure, signals are transmitted and received continuously. For example, the transmission and reception of digital signals occur at intervals of several milliseconds.

[0028] Within the scope of this disclosure, the term "moisture content" describes the concentration (expressed as a percentage [%) of water (vapor) in a gas mixture within an anode piping system. Here, moisture content can be either the relative humidity or the absolute humidity of the gas mixture.

[0029] Figure 1 A schematic diagram of the present invention's fuel cell system 100 for use in a vehicle is shown. The fuel cell system 100 includes a fuel cell 110, such as a fuel cell stack. As known from the prior art, the fuel cell 110 herein includes an anode and a cathode, which are separated from each other by a membrane. For example, the fuel cell 110 may be a so-called PEM fuel cell, wherein the membrane is a proton exchange membrane through which protons formed at the anode can reach the cathode.

[0030] Furthermore, the fuel cell system 100 includes a hydrogen tank 120, in which substantially pure hydrogen is stored, preferably under pressure. The hydrogen tank 120 may have a valve (in... Figure 1 (Not explicitly shown in the text) These valves can control the inflow of hydrogen into and out of hydrogen tank 120.

[0031] also, Figure 1The fuel cell system 100 includes an anode piping system 130 designed to deliver hydrogen from a hydrogen tank 120 to the anode of the fuel cell 110, and to discharge or return the gas mixture flowing through the anode. For this purpose, the anode piping system 130 includes an anode inlet line 132 fluidly connected to a hydrogen injector 122, which is designed to inject hydrogen from the hydrogen tank 120 into the anode piping system 130, particularly the anode inlet line 132. The anode inlet line 132 is fluidly connected to an anode line 134 that delivers the gas mixture to the anode of the fuel cell 110. The anode piping system 130 also includes an anode outlet line 136 fluidly connected to the anode line 134, which can discharge the gas mixture flowing through the anode line 134 and deliver it to an exhaust system (in...). Figure 1 (Not explicitly shown). The anode piping system 130 also includes an anode return line 138 that fluidly connects the anode output line 136 to the anode input line 132, and a return pump 139 is arranged in the anode return line. The return pump is designed to return the gas mixture flowing through the anode output line 136 to the anode input line 132 at a predetermined circulation rate (in liters per second [l / s]). For example, the circulation rate can be adjusted and set by a control signal of the return pump 139. Thus, a loop is formed between the anode input line 132, the anode line 134, the anode output line 136, and the anode return line 138, in which the gas mixture can be circulated and guided by means of the return pump 139.

[0032] Upon receiving a corresponding hydrogen delivery signal, the hydrogen injector 122 can inject hydrogen from the hydrogen tank 120 into the anode piping system 130 at a predetermined hydrogen delivery rate. For example, the hydrogen delivery rate (in liters per second [l / s]) can be determined and / or set based on the pressure in the hydrogen tank 120, the temperature of the hydrogen in the hydrogen tank, the opening cross-section of the hydrogen injector 122, the pulse duration, the injection frequency, and / or the injection range.

[0033] The anode piping system 130 also includes a purge valve 137, which is located downstream of the junction of the anode return line 138 in the anode output line 136 and is designed to release or block the anode output line 136. During normal operation of the fuel cell 110, the purge valve 137 is closed, thereby enabling the circulation of the circuit and gas mixture described above to be provided by means of the return pump 139.

[0034] Furthermore, the anode conduit system 130 has a thermal conductivity sensor (also known as a hydrogen sensor) 131, which is arranged downstream of the hydrogen injector 122 in the anode input conduit 132 and is designed to generate a gas signal representing the thermal conductivity of the gas mixture in the anode conduit system 130, particularly in the anode input conduit 132, immediately downstream of the hydrogen injector 122. Due to the cross-sensitivity of the thermal conductivity sensor 131 to the humidity in the gas mixture, the gas signal also represents the sum of the moisture content, hydrogen concentration, and nitrogen concentration in the gas mixture within the anode conduit system 130, particularly in the anode input conduit 132. Here, the thermal conductivity sensor 131 can be a gas sensor based on the principle of thermal conductivity. The gas signal from the thermal conductivity sensor 131 is preferably a digital signal or data that can be processed by a data processing device having a processor and memory.

[0035] The fuel cell system 100 also includes a cathode piping system 140, which comprises a cathode inlet pipe 142, a cathode pipe 144 connected to the cathode, and a cathode outlet pipe 146. Furthermore, the cathode piping system 140 includes a cathode bypass 148 that fluidly connects the cathode inlet pipe 142 to the cathode outlet pipe 146, and a bypass valve 149 is arranged in the cathode bypass for blocking or releasing the cathode bypass pipe 148. The cathode outlet pipe 146 can discharge air supplied to the cathode through the cathode inlet pipe 142 to the exhaust system. A pressure sensor 141 for detecting the pressure in the cathode inlet pipe 142 and a cathode inlet valve 145, such as a throttle valve, can be arranged in the cathode inlet pipe 142. Similarly, the cathode outlet pipe 146 can have a cathode outlet valve 147 and a pressure sensor 143 arranged downstream of the cathode outlet valve in the cathode outlet pipe 146 for detecting the pressure in the cathode outlet pipe 146. In addition, a compressor 170 for compressed air, a water separator 172, and a throttle valve 174 are arranged in the cathode piping system 140.

[0036] Figure 1 The fuel cell system 100 also has an electrical system branch 150 that includes power consumers. In particular, the electrical system branch 150 describes at least a portion of the electrical system capable of storing and distributing the electrical energy generated by the fuel cell 110.

[0037] from Figure 1 It can also be seen that a control device 160 is provided, which can be connected to all structural components of the fuel cell system 100. Although in Figure 1The separate wiring for this purpose is not shown, but such electrical connections can exist in the form of connecting wires or wireless communication devices. The control device 160 may have multiple control device sections, such as a first control device section 162, a second control device section 164, a third control device section 166, a fourth control device section 168, and a fifth control device section 169, which will also be referenced below. Figure 3 To elaborate on it in more detail.

[0038] The control device 160 may have a processor or computing unit and memory. Alternatively, the control device 160 may be a processor or computing unit connected to memory. The processor or computing unit may be a central processing unit (CPU). The processor or computing unit may also be other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate logic devices, transistor logic devices, discrete hardware components, etc. The general-purpose processor may be a microprocessor, or the processor may be any conventional processor, etc.

[0039] The memory includes, but is not limited to, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM), or portable read-only memory (e.g., CD-ROM). The memory is configured to store associated program instructions and related data.

[0040] Optionally, the anode piping system 130 may have an additional thermal conductivity sensor 133, such as Figure 1 As shown, the additional thermal conductivity sensor is arranged in the anode return line 138 and is designed to generate a gas signal representing the thermal conductivity of the gas mixture in the anode system 130, particularly in the anode return line 138, downstream of the anode and upstream of the hydrogen injector 122. Due to the cross-sensitivity of the thermal conductivity sensor 133 to humidity in the gas mixture, the gas signal from the additional thermal conductivity sensor 133 also represents the sum of the moisture content, hydrogen concentration, and nitrogen concentration in the gas mixture downstream of the anode, particularly in the anode return line 132. The gas signal from the thermal conductivity sensor 132 is preferably a digital signal or data that can be processed by a data processing device having a processor and memory.

[0041] Thermal conductivity sensor 131, together with control device 160, forms gas mixture analysis device 180 for fuel cell system 100 (see...). Figure 1 (The dashed box in the image). Optionally, the gas mixture analysis device 180 may have an additional thermal conductivity sensor 133.

[0042] Figure 2 An exemplary diagram is shown, in which the following is plotted: Figure 1 An exemplary time curve of the gas signal 200 from the thermal conductivity sensor 131 of the fuel cell system is shown. Here, time t is plotted on the horizontal axis, and the gas signal representing the thermal conductivity L of the mixture at the measurement point is plotted on the vertical axis.

[0043] The gas mixture in the anode piping system 130 consists of hydrogen, water (vapor) or moisture and nitrogen. Since the thermal conductivity of hydrogen is significantly higher than that of the other components (water (vapor) and nitrogen), the thermal conductivity of the gas mixture is mainly affected by the hydrogen concentration.

[0044] exist Figure 2 At time t1, when the fuel cell system 100 is in normal operating mode, a first gas signal is generated using the thermal conductivity sensor 131. At time t2, a hydrogen delivery signal is sent to the hydrogen injector 122 using the control device 160, causing the hydrogen injector 122 to inject hydrogen from the hydrogen tank 120 into the anode pipeline system 130 at a predetermined hydrogen delivery rate. At time t3, a second gas signal is generated using the thermal conductivity sensor 131. At time t4, the injection of hydrogen into the anode pipeline system 130 using the hydrogen injector 122 ends. At time t5, when the fuel cell system 100 is back in normal operating mode, a third gas signal is generated using the thermal conductivity sensor 131, and the hydrogen concentration should be deduced based on the third gas signal.

[0045] The following is for reference. Figure 3 The flowchart shown illustrates an exemplary embodiment of the method according to the present invention, which is used to determine the presence of Figure 1 The moisture content in the gas mixture of the anode line system 130 of the fuel cell system 100 is used to determine the corrected hydrogen signal, which indicates the presence of moisture in the gas mixture. Figure 1 The hydrogen concentration in the gas mixture in the anode piping system 130 of the fuel cell system 100.

[0046] Figure 3 The method begins with step 300, then proceeds to step 310, in which... Figure 1During normal operation of the fuel cell system 100, the control device 160, particularly the first control device section 162, receives a (digital) first gas signal from the thermal conductivity sensor 131. This first gas signal represents the thermal conductivity of the gas mixture in the anode piping system 130, particularly in the anode input piping 132. The first gas signal is received from the thermal conductivity sensor 131 at a first time t1 (see...). Figure 2 (This was done)

[0047] During normal operation of the fuel cell system 100, the purge valve 137 is in the closed position, meaning that the gas mixture from the anode line system 130 cannot flow through the purge valve 137. Simultaneously, during normal operation of the fuel cell system 100, the return pump 139 is activated, allowing the gas mixture present in the anode line system 130 to flow at a predetermined circulation rate through the loop formed by the anode input line 132, anode line 134, anode output line 136, and return line 138.

[0048] During operation of the fuel cell system 100, the hydrogen injector 122 is shut down, and (fresh) hydrogen is not injected into the anode line system 130. The gas mixture in the anode line system 130 contains hydrogen, nitrogen, and water (vapor). The water (vapor) content may be referred to as the moisture content. The proportions, concentrations, or contents of the respective components of the gas mixture in the anode line system vary by location and change according to the conversion of hydrogen at the anode. Therefore, due to the conversion of hydrogen at the anode, the hydrogen concentration in the gas mixture decreases, and thus the thermal conductivity of the gas mixture also decreases (see...). Figure 2 The curve of the gas signal 200, which is earlier than the first moment t1, is basically decreasing.

[0049] In subsequent step 320, control device 160, particularly the second control device section 164, sends a hydrogen delivery signal to hydrogen injector 122 as needed. The hydrogen delivery signal is designed to cause hydrogen injector 122 to inject hydrogen from hydrogen tank 120 into anode piping system 130, particularly anode input piping 132, at a predetermined hydrogen delivery rate. The injection of hydrogen from hydrogen tank 120 into anode piping system 130 begins at a second time t2 and continues until a third time t3. Preferably, the first time t1 and the second time t2 are the same.

[0050] Because hydrogen is injected into the anode piping system 130, the hydrogen concentration in the gas mixture increases significantly at the measurement point of the thermal conductivity sensor 131, and therefore the thermal conductivity of the gas mixture also increases significantly (see...). Figure 2The curve of the gas signal 200 that appears immediately after the second time t2. After this rise, the gas signal remains substantially constant during the hydrogen injection process because the circulation rate of the return pump 139 is substantially constant and the hydrogen delivery rate of the hydrogen injector 122 is substantially constant, and the hydrogen concentration reaches a substantially constant value.

[0051] In the subsequent step 330, the control device 160, and more particularly the first control device section 162, receives a second gas signal from the thermal conductivity sensor 131. Here, the reception of the second gas signal occurs at a fourth time t4, preferably during the injection of hydrogen from the hydrogen tank 120. Alternatively, the fourth time t4 and the third time t3 can coincide. In another alternative design, the fourth time t4 immediately follows the third time t3, where it must be ensured that there is still injected hydrogen reaching the measurement point.

[0052] In the subsequent step 340, the control device 160, particularly the third control device section 166, can determine the moisture content in the anode piping system 130, particularly the anode input piping 132, based at least in part on the first gas signal received at the first time t1, at least in part on the second gas signal received at the fourth time t4, and at least in part on a predetermined hydrogen delivery rate. In a preferred design, the circulation rate of the reflux pump 139 can also be considered at this time.

[0053] Here, the present invention utilizes the fact that: due to the process of injecting hydrogen into the anode pipeline system 130 between time t2 and t3, the gas signal 200 rises, and during the injection, the gas signal remains at least partially constant (see...). Figure 2 The gas signal 200 is between time t2 and t3. For example, if the gas mixture in the anode input line 132 consists of approximately 80% hydrogen, approximately 10% nitrogen, and approximately 10% moisture before injection and flows in the anode line system 130 at a circulation rate of 5 l / s, and then hydrogen is injected at a hydrogen delivery rate of 5 l / s by means of the hydrogen injector 122, the thermal conductivity t of the gas mixture is significantly increased (see [reference]). Figure 2 The curve of the gas signal 200 immediately follows the second time point t2.

[0054] Of particular interest is the presence of a gas mixture with high humidity in the anode piping system 130. That is, the gas mixture should contain moist hydrogen, for example, 100% hydrogen with a relative moisture content of 70%. Depending on the temperature and pressure, this can be expressed, for example, in molar units, as a hydrogen concentration of 80% and a moisture content of 20% (with a nitrogen content of 0%). The 80% hydrogen concentration can then be determined from the thermal conductivity of the gas mixture, as determined by the thermal conductivity sensor 131.

[0055] However, if a "dry" gas mixture is present in the anode piping system 130, such as a mixture of 80% hydrogen, 20% nitrogen, and 0% moisture, the 80% hydrogen concentration can still be determined using the thermal conductivity sensor 131. That is, the thermal conductivity sensor 131 can determine the 80% hydrogen concentration and the remaining 20% ​​mixture concentration (moisture and nitrogen). However, the system conditions differ in a gas mixture of 80% hydrogen and 20% moisture compared to a gas mixture of 80% hydrogen and 20% nitrogen.

[0056] According to the present invention, the moisture content of a gas mixture can be determined by means of two gas signals and a predetermined hydrogen delivery rate, using known thermodynamic relationships.

[0057] then, Figure 3 The method can proceed to step 350, in which the control device 160, particularly the fourth control device section 168, sends a moisture signal indicating the moisture content determined in step 340.

[0058] In a further step 360, the control device 160, and in particular the first control device section 162, receives a third gas signal from the thermal conductivity sensor 131 at a fifth moment t5 when the fuel cell system 100 is back in normal operation mode and no hydrogen is injected into the anode pipeline system 130.

[0059] In the subsequent step 370, control device 160, particularly the fourth control device section 169, determines the hydrogen concentration in the anode piping system 130 based at least in part on the moisture content determined in step 340 and at least in part on the third gas signal received in step 360. In particular, the third gas signal can be corrected using the moisture content, and thus the actual hydrogen concentration can be determined. The determined moisture content can be used as a control / regulation variable for the operation of the fuel cell system, thereby enabling the fuel cell system to achieve a longer lifespan.

[0060] In the subsequent step 380, the control device 160, especially the fourth control device section 168, can send a hydrogen signal indicating the hydrogen concentration determined in step 370, after which the method ends in step 390.

[0061] An optional thermal conductivity sensor 133 is present therein (see Figure 1 In an alternative design scheme, after step 320, at the sixth time t6 immediately following the second time t2 (see...), Figure 2 Step 310 is performed together with step 330. At this time, control device 160, especially the first control device section 162, receives the second gas signal from thermal conductivity sensor 131 and the first gas signal from thermal conductivity sensor 133. In particular, at the sixth time t6, it can be assumed that thermal conductivity sensor 131 has measured the gas mixture in which (fresh) hydrogen from hydrogen tank 120 has just been injected, while thermal conductivity sensor 133 measures the gas mixture in which no injected hydrogen has yet been added.

[0062] Therefore, in this alternative design, the gas signals from the two thermal conductivity sensors can be mutually verified and calibrated during normal operation of the fuel cell system 100.

[0063] In a preferred design, step 340 further determines a rate ratio between the circulation rate of the reflux pump 139 and the predetermined hydrogen delivery rate of the hydrogen injector 122. Furthermore, in step 340, the determined rate ratio can be additionally considered when determining the moisture content.

[0064] Therefore, through this invention, it is possible to: determine the moisture content of the gas mixture present in the anode piping system 130, and, while the fuel cell system continues to operate, use this moisture content to correct the gas signal of the thermal conductivity sensor 131, so that the actual hydrogen concentration in the anode piping system 130 can be determined as accurately as possible.

Claims

1. A method for determining the moisture content in a gas mixture present in an anode conduit system (130) of a fuel cell system (100), wherein the anode conduit system (130) fluidly connects a hydrogen injector (122) to the anode of the fuel cell system (100), the hydrogen injector being configured to deliver hydrogen from a hydrogen tank (120) to the anode conduit system (130), wherein the anode conduit system (130) has at least one thermal conductivity sensor (131, 133) configured to generate a gas signal representing the thermal conductivity of the gas mixture in the anode conduit system (130), wherein the gas mixture comprises hydrogen and nitrogen, and wherein the method comprises: - Receive a first gas signal from the at least one thermal conductivity sensor (131, 133) at a first time (t1); - At the second moment (t2), a hydrogen delivery signal is sent to the hydrogen injector (122), wherein, The hydrogen delivery signal causes the hydrogen injector (122) to deliver hydrogen from the hydrogen tank to the anode pipeline system (130) at a predetermined hydrogen delivery rate between the second time (t2) and the third time (t3); - At a fourth moment (t4), when hydrogen is being or has been supplied to the anode piping system (130) from the hydrogen tank (120), a second gas signal is received from the at least one thermal conductivity sensor (131, 133); and The moisture content in the anode piping system (130) is determined based at least in part on the first gas signal, at least in part on the second gas signal, and at least in part on the predetermined hydrogen delivery rate.

2. The method according to claim 1, wherein the first time moment (t1) is earlier than or the same as the second time moment (t2).

3. The method according to any one of the preceding claims, wherein the fourth time point (t4) is later in time than the second time point (t2) and earlier in time than the third time point (t3) or is the same as the third time point (t3).

4. The method according to any one of the preceding claims, wherein the second gas signal represents the thermal conductivity of the gas mixture at a location immediately downstream of the hydrogen injector (122).

5. The method according to any one of the preceding claims, wherein the first gas signal represents the thermal conductivity of the gas mixture at a location downstream of the anode.

6. The method according to any one of the preceding claims, wherein the method further comprises: - At a fifth time (t5), which is later in time than the third and fourth times (t3, t4), a third gas signal is received from the at least one thermal conductivity sensor; and - The hydrogen concentration is determined based at least in part on the determined moisture content and at least in part on the third gas signal received at the fifth time (t5).

7. The method according to any one of the preceding claims, wherein the anode piping system (130) has a reflux pump (139) configured to circulate a gas mixture flowing through the anode piping system (130) in a loop at a predetermined circulation rate, such that the gas mixture is repeatedly delivered to the anode, wherein the method comprises: - Determine the rate ratio between the circulation rate of the reflux pump (139) and the hydrogen delivery rate of the hydrogen injector (122). The determination of the moisture content in the anode piping system (130) is also based at least in part on the determined rate ratio.

8. A control device (160) configured to perform the steps of the method according to any one of the preceding claims.

9. The control device (160) according to claim 8, wherein the control device comprises: - A first control device section (162) is used to perform the step of receiving the first gas signal and the second gas signal from the at least one thermal conductivity sensor (131, 133); - A second control unit section (164) is used to perform the step of sending a hydrogen delivery signal to the hydrogen injector (122); and - A third control unit section (166) is used to perform the step of determining the moisture content in the anode piping system (130).

10. The control device (160) according to any one of claims 8 and 9, wherein the control device further comprises: - A fourth control unit section (168) for performing the step of determining the hydrogen concentration.

11. A gas mixture analysis device (180) for a fuel cell system (100), the gas mixture analysis device comprising: - At least one thermal conductivity sensor (131, 133), said at least one thermal conductivity sensor being designed to generate a gas signal; and - The control device (160) according to any one of claims 8 to 10.

12. The gas mixture analysis apparatus (180) according to claim 11. The first thermal conductivity sensor (131) is designed to generate a second gas signal representing the thermal conductivity of the gas mixture present in the anode line system (130) of the fuel cell system (100) downstream of the hydrogen injector. The second thermal conductivity sensor (133) is designed to generate a first gas signal representing the thermal conductivity of the gas mixture present in the anode piping system (130) of the fuel cell system (100) downstream of the anode.

13. A fuel cell system (100), the fuel cell system comprising: -anode; - An anode piping system (130) that connects a hydrogen injector (122) to the anode fluid, the hydrogen injector being designed to deliver hydrogen from a hydrogen tank (120) to the anode piping system (130); and - Gas mixture analysis apparatus (180) according to any one of claims 11 and 12.

14. A computer program comprising instructions that, when executed by a computing unit, cause the computing unit to perform the method according to any one of claims 1 to 7.

15. A computer-readable medium on which a computer program according to claim 14 is stored.

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