Method and module for controlling a valve for regulating the internal pressure of a fluid circuit in an electrochemical device - Patents.com

Abstract

The internal pressure (P int ), the fluid circuit (3) is a method for controlling a pressure regulating valve (6) for regulating an external pressure (P ext ) and the internal pressure (P int ) is supplied by a compressor (4) compressing air at external pressure (P ext ) and measuring the internal pressure (P int ) and the compression ratio (A) to promote the overall efficiency (R1) of the electrochemical device (2) and the compressor (4). ext ) and the compression range (B), the internal pressure setting value (P int * ) and the step of determining the internal pressure setting value (P int * and controlling the pressure regulating valve (6) to reach a pressure equal to or greater than the pressure equal to the pressure in the pressure regulator (4).

Description

[Technical field]

[0001] The present invention relates to the field of electrochemical devices (fuel cells, electrolyzers, etc.) particularly on board aircraft, and is particularly directed to the regulation of the internal pressure in such electrochemical devices. [Background technology]

[0002] As is known, a fuel cell makes it possible to generate electrical energy from a redox reaction between hydrogen as a fuel and oxygen present in the air as an oxidant. With reference to Fig. 1, the fuel cell 200 comprises a stack of several cells 210 in which the redox reaction takes place, these cells 210 being held between two end plates 220 to allow the collection of the electrical energy generated. The fuel cell 200 also comprises a cathode circuit 300 and an anode circuit 310, which make it possible to supply the cells 210 with air and hydrogen, respectively, and to discharge the products of the redox reaction, namely water and traces of hydrogen and air.

[0003] In the context of a fuel cell 200 on board an aircraft, the air for the cathode circuit 300 is conventionally taken inside or outside the aircraft, i.e. in an external environment whose physicochemical properties change depending on the altitude. In particular, the external pressure P ext The atmospheric pressure, called the atmospheric pressure, decreases with altitude, reaching, for example, about 9000 Pa at a high aircraft altitude of 17000 m. The same applies in particular to the air temperature and oxygen concentration. Such variations can change the operating conditions of the fuel cell 200 and reduce the performance of the fuel cell 200, which is undesirable.

[0004] In order to control the operating conditions of the fuel cell 200, it is known to install a compressor 400 upstream of the cathode circuit 300 and a valve 600 downstream of the cathode circuit 300 for adjusting the internal pressure. As shown in FIG. 1, the compressor 400 regulates an imposed mass flow rate Q opt and internal pressure P optThe regulating valve 600 allows compressed air taken from the external environment to be injected into the cathode circuit 300 according to the imposed internal pressure P opt In order to maintain and optimise its efficiency, some of them are provided with variable passage sections. An embodiment according to the same principle is known from French patent application FR 3 074 363 A1.

[0005] However, in reality, the external pressure P ext The variations in pressure, pressure, and flow rate require dimensioning of the compressor 400 with a wide compression ratio range in order to maintain optimal performance of the fuel cell 200. Such dimensioning of the compressor 400 undesirably increases its mass, its volume, and its cost.

[0006] Furthermore, optimizing the efficiency of the fuel cell 200, especially at high altitudes, requires high power consumption of the compressor 400. The compressor 400 is conventionally electrically powered by the fuel cell 200, with the result that the gains in electricity generation of the fuel cell 200 intended to supply the aircraft are at least partially lost due to the power consumption of the compressor 400.

[0007] To eliminate these drawbacks, one solution is to reduce the imposed internal pressure P in the cathode circuit 300. opt However, this would unacceptably reduce the performance of the fuel cell 200.

[0008] The present invention therefore aims to eliminate at least some of these drawbacks by proposing a method and a module for controlling a valve for regulating the internal pressure of a fuel cell, more generally an electrochemical device, and in particular an electrochemical device on board an aircraft.

[0009] Prior art fuel cells are known in the art from US Patent Application Publication No. 20190267645A1, WO Patent Application Publication No. 2011089502A1, and US Patent Application Publication No. 20080088043A1. [Prior art documents] [Patent documents]

[0010] [Patent Document 1] French Patent Application Publication No. 3074363 [Patent Document 2] US Patent Application Publication No. 2019 / 0267645 [Patent Document 3] International Publication No. 2011 / 089502 [Patent Document 4] US Patent Application Publication No. 2008 / 0088043 Summary of the Invention [Means for solving the problem]

[0011] The present invention relates to a method for controlling a valve for regulating the internal pressure of a fluid circuit in an electrochemical device, said fluid circuit being supplied by a compressor configured to take in a fluid at an external pressure and to compress it to an internal pressure according to a compression ratio belonging to a predetermined compression range, said method comprising the step of controlling a regulating valve to reach a set internal pressure.

[0012] The present invention relates to a method comprising: - Prescribed data, namely: - the efficiency of the electrochemical device as a function of the internal pressure, - Compressor efficiency as a function of the compression ratio, - Overall efficiency depending on the efficiency of the electrochemical device and the efficiency of the compressor It was implemented from - Here's how: - measuring an external pressure; - determining a set internal pressure from the measured external pressure and the compression range so as to improve overall efficiency; It is notable that it includes:

[0013] The invention advantageously makes it possible to improve the overall efficiency obtained by the electrochemical device, i.e. the efficiency of the electrical production system formed by the assembly of the electrochemical device and the associated elements enabling its operation. The associated elements designate in particular the compressors supplying the fluid circuits of the electrochemical device, the cooling circuits of the electrochemical device, etc. Such an overall efficiency is therefore based on the electricity generation of the electrochemical device, but also on the power consumption of its associated elements. This makes it possible to take into account the power actually generated by the electrochemical device, which corresponds directly or indirectly to the power it generates minus the power it consumes for its operation. Such a global approach differs from the prior art, which aims to improve the efficiency of only the electrochemical device, without taking into account the associated elements.

[0014] To improve the overall efficiency, the invention proposes to regulate in a simple and practical way a single parameter, namely the internal pressure of the fluid circuit, advantageously by controlling a regulating valve installed downstream, the determined set internal pressure being advantageously based on physicochemical data of the environment in which the electrochemical device is located, in particular the external pressure, and on performance data of the electrochemical device and its associated elements, in particular the compressor.

[0015] According to one aspect of the present invention, the step of determining a set internal pressure comprises: - calculating a test efficiency of the electrochemical device from a test internal pressure, the test internal pressure being calculated from the measured external pressure and a predetermined compression test ratio belonging to a compression range so as to improve the efficiency of the compressor; - a new stage of calculating the test efficiency from an incremented new test compression ratio that belongs to the compression range of the compressor, as long as the test efficiency of the electrochemical device is below a predetermined minimum efficiency threshold. Including, The set internal pressure corresponds to the test internal pressure at which the test efficiency complies with the minimum efficiency threshold.

[0016] Such a test methodology therefore consists in verifying that from an acceptable hypothetical compression ratio for the compressor, the efficiency of the corresponding electrochemical device is also acceptable. Such a test methodology makes it possible to determine, from simple measurements of the external pressure and the performance data of the electrochemical device and its associated elements, the internal pressure value at which both the electrochemical device and its associated elements are in good operating condition. In particular, the set internal pressure chosen at the end of the determination step ensures good efficiency of the electrochemical device while limiting the power consumption of the compressor. When the external pressure is changed, a new set internal pressure can be determined practically.

[0017] According to another aspect of the present invention, the step of determining a set internal pressure comprises: - calculating a range of allowable internal pressures from the measured external pressures and compression ranges; - The measured external pressure redefines the overall efficiency according to the internal pressure, resulting in a gradual increase in the overall efficiency over the range of allowable internal pressures. Including, The set internal pressure corresponds to the allowable internal pressure at which the overall efficiency is maximum.

[0018] Such an optimization method considers the efficiency of the electrochemical device as a function of the internal pressure and the efficiency of the compressor as a function of two variables, namely the internal pressure and the external pressure. From a measurement of the external pressure, the overall efficiency is written as a function of the internal pressure and is maximized over the range of allowable internal pressures. Such a method advantageously makes it possible to determine an optimal operating point of the energy generation system that differs from the operating point of the electrochemical device, especially when the external pressure is high, such as at high altitudes when on board an aircraft.

[0019] According to one aspect of the present invention, the efficiency of the electrochemical device is proportional to the internal pressure, and the efficiency of the compressor is inversely proportional to the internal pressure at a constant external pressure. Therefore, the determined set internal pressure is selected to be high enough to improve the performance of the electrochemical device and low enough to limit the energy consumption of the compressor.

[0020] According to one aspect of the present invention, an electrochemical device is cooled by a cooling circuit having a predetermined efficiency according to the internal pressure, and the overall efficiency depends on the efficiency of the cooling circuit. With the determined set internal pressure, it is possible to improve the operation of the energy generation system as a whole, advantageously by taking into account the energy consumption of the compressor and the cooling circuit.

[0021] According to one aspect of the present invention, the efficiency of the electrochemical device depends on the oxygen level in the fluid circuit, the control method includes the step of measuring the oxygen level in the fluid circuit, and the determination step is carried out from the measured oxygen level. The set internal pressure is advantageously determined from some physicochemical conditions of the environment in which the electrochemical device is installed, namely the external pressure and the existing oxygen level.

[0022] According to one aspect of the present invention, the electrochemical device is in the form of a fuel cell, and preferably the fluid circuit is in the form of the cathode circuit of the fuel cell, preferably through which air flows. The operating conditions of the fuel cell are advantageously based in particular on the physicochemical conditions of the external environment in which the fuel cell is installed, such as the external pressure and the oxygen level of the air.

[0023] According to one aspect of the present invention, the electrochemical device comprises a second fluid circuit with a second internal pressure controlled by a second regulating valve, and the control method is such that |P10 * -P int * | Verifying the second set internal pressure P10 of S2 * including the step of controlling the second regulating valve to reach, where S2 designates a predetermined maximum pressure fluctuation threshold value, and P int *is the set internal pressure of the first regulating valve of the first fluid circuit. Here, the first fluid circuit and the first regulating valve designate the previously mentioned fluid circuit and regulating valve and are distinguished from the second fluid circuit and the second regulating valve. The method according to the invention thus makes it possible to control the internal pressure in both the oxidizer circuit and the fuel circuit of the electrochemical device. This makes it possible to ensure a substantially homogeneous pressure in the electrochemical device and thus to ensure its correct operation and to increase its service life.

[0024] According to a preferred embodiment of the invention, the second fluid circuit is in the form of a fuel cell anode circuit, preferably through which hydrogen flows. The method according to the invention therefore makes it possible to control the internal pressure in both the oxidant circuit and the fuel circuit of the fuel cell.

[0025] According to one aspect of the invention, an electrochemical device is installed on board an aircraft to ensure at least part of its electrical energy supply, and said method is carried out during the flight of the aircraft. The method according to the invention is particularly advantageous for electrochemical devices installed on board an aircraft, since the physicochemical conditions vary significantly depending on the altitude. The method according to the invention therefore makes it possible to adapt the set internal pressure during flight, so as to improve the overall efficiency, regardless of the altitude of the aircraft.

[0026] The invention also relates to a module for controlling a valve for regulating the internal pressure of a fluid circuit in an electrochemical device for the implementation of the aforementioned method, said fluid circuit being supplied by a compressor configured to take in a fluid at an external pressure and to compress it to an internal pressure according to a compression ratio belonging to a predetermined compression range, said control module comprising: - a member for measuring external pressure; - Prescribed data, namely: - the efficiency of the electrochemical device as a function of the internal pressure, - Compressor efficiency as a function of the compression ratio, - Overall efficiency depending on electrochemical efficiency and compressor efficiency A member for storing the - a calculation member configured to determine a set internal pressure from the measured external pressure and the compression range so as to improve the overall efficiency; - Valve actuator of the regulating valve to reach the set internal pressure; The present invention relates to a module comprising:

[0027] The invention will be better understood on reading the following description, given by way of example, and with reference to the following figures, given by way of non-limiting example, in which similar objects are marked with the same reference symbols: [Brief description of the drawings]

[0028] [Figure 1] FIG. 1 is a schematic diagram of a fuel cell installed on an aircraft according to the prior art. [Diagram 2] 1 is a schematic diagram of a fuel cell installed on an aircraft according to one embodiment of the present invention; [Diagram 3] 3 is a schematic diagram of a method for controlling a regulator valve of the fuel cell of FIG. 2, according to one embodiment of the present invention. [Figure 4A] FIG. 4 is a schematic diagram of a step of determining a set internal pressure in the method of FIG. 3 according to one embodiment of the present invention. [Figure 4B] FIG. 4B is a schematic diagram of the calculation stages during the implementation of the decision step of FIG. 4A. [Figure 4C] FIG. 4B is a schematic diagram of the calculation stages during the implementation of the decision step of FIG. 4A. [Figure 5A] 4 is a schematic diagram of a step of determining a set internal pressure of the method of FIG. 3 according to an alternative embodiment of the present invention. [Figure 5B] FIG. 5B is a schematic diagram of the calculation stages during the implementation of the decision step of FIG. 5A. [Figure 5C] FIG. 5B is a schematic diagram of the calculation stages during the implementation of the decision step of FIG. 5A. [Figure 6A] 2 is a schematic diagram of a fuel cell installed on an aircraft according to another embodiment of the present invention. [Figure 6B] 6B is a schematic diagram of a method for controlling a regulator valve of the fuel cell of FIG. 6A according to another embodiment of the present invention. [Figure 7A]2 is a schematic diagram of a fuel cell installed on an aircraft according to another embodiment of the present invention. [Figure 7B] 7B is a schematic diagram of a method for controlling a regulator valve of the fuel cell of FIG. 7A according to another embodiment of the present invention. [Figure 8A] 2 is a schematic diagram of a fuel cell installed on an aircraft according to another embodiment of the present invention. [Figure 8B] 8B is a schematic diagram of a method for controlling a regulator valve of the fuel cell of FIG. 8A according to another embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0029] It should be noted that the drawings represent the invention in detail for carrying out the invention and, if applicable, the invention can of course be better defined using said drawings.

[0030] The present invention relates to a method for controlling a valve for regulating the internal pressure of a fluid circuit in an electrochemical device. The invention aims to improve the efficiency of electrochemical devices on a global scale in an environment with varying physicochemical properties. In the following, the invention is described in the context of a fuel cell installed on board an aircraft in order to regulate the internal air pressure in a fluid circuit in the form of a cathode circuit. However, it goes without saying that the electrochemical device may have a form other than a fuel cell, such as an electrolyser or a catalytic reactor, and / or may be installed in an environment different from that of an aircraft. The fluid circuit may have another form, such as an anode circuit, and / or may allow the circulation of any fluid.

[0031] As explained in the introduction, a fuel cell makes it possible to generate electrical energy from a redox reaction between hydrogen as fuel and oxygen present in the air as oxidant. With reference to Fig. 2, the fuel cell 2 comprises a stack of several cells 21 in which the redox reaction takes place, these cells 21 being held between two end plates 22 to allow the collection of the electrical energy generated. The fuel cell 2 also comprises a cathode circuit 3 and an anode circuit 10, which make it possible to supply the cells 21 with air and hydrogen, respectively, and to discharge the products of the redox reaction, namely water and traces of hydrogen and air.

[0032] As explained in the introduction, in the context of a fuel cell 2 on board an aircraft, the air for the cathode circuit 3 is conventionally taken from inside or outside the aircraft, i.e. from the external environment, whose physicochemical properties are variable depending on the altitude. In particular, the external pressure P ext The atmospheric pressure, called the atmospheric pressure, decreases with altitude, reaching, for example, about 9000 Pa at a high aircraft altitude of 17000 m. The same applies to the temperature and oxygen concentration of the air, among others.

[0033] As explained in the introduction and shown in FIG. 2, a compressor 4 and a regulating valve 6 are mounted upstream and downstream, respectively, of the cathode circuit 3. The compressor 4 and the regulating valve 6 together regulate the internal pressure P int and the mass flow rate Q, so that the operating conditions of the fuel cell 2 can be controlled. More precisely, the compressor 4 controls the external pressure P ext It allows the air taken from the external environment to be compressed according to a compression ratio A, which belongs to a compression range B specific to the compressor 4. The compression ratio A of the compressor 4 is controlled by a control device 5 according to the desired mass flow rate Q of air in the cathode circuit 3.

[0034] As explained in the introduction and shown in FIG. 2, the regulating valve 6 regulates the desired internal pressure P intThe regulator valve 6 has a variable passage section in part that is controlled by a valve actuator 7 in response to pressure. Thus, the regulator valve 6 is pressure dependent and the compressor 4 is flow dependent and controls the operating conditions of the fuel cell 2 and therefore its efficiency.

[0035] According to the present invention, as shown in Figs. 2 and 3, the internal pressure P int is adjusted by implementing a method for controlling the regulating valve 6 from the following predetermined data: - Internal pressure P of cathode circuit 3 int Efficiency R2 of fuel cell 2 depending on - the efficiency R4 of compressor 4 as a function of the compression ratio A, and an overall efficiency R1 depending on the efficiency R2 of the fuel cell 2 and the efficiency R4 of the compressor 4;

[0036] Further according to the present invention, as shown in FIGS. 2 and 3, the control method includes: - Outside air pressure P ext Step E1, measuring - The measured external pressure P is adjusted to improve the overall efficiency R1. ext and the compression range B of the compressor 4 to the set internal pressure P int * a step E2 of determining - Set internal pressure P int * Step E3: controlling the regulating valve 6 so that

[0037] As will be explained below, according to a first embodiment, the determination step E2 involves determining several internal pressure test values ​​P associated with an acceptable efficiency R4 of the compressor 4. int According to a second embodiment, the determination step E2 is carried out by comparing the efficiency R2 of the fuel cell 2 with the internal pressure P int This is done by maximizing the overall efficiency R1 over the range

[0038] Therefore, the control method according to the present invention adjusts the internal pressure P in the cathode circuit 3 so as to improve the overall performance of the electricity generating system 1.int As shown in FIG. 2, such an electricity generating system 1 includes a fuel cell 2 and associated elements that enable the operation of the fuel cell 2, such as a compressor 4 that supplies oxidant to the fuel cell 2. Thus, the determined set internal pressure P int * This makes it possible to improve the generated energy made available to the aircraft, which corresponds to the energy generated at the outlet of the fuel cell 2 minus the energy consumed by the relevant elements, such as the energy used to compress the outside air.

[0039] The steps of the control method according to the first embodiment of the present invention will be described below, followed by the steps of the control method according to the second embodiment of the present invention. Another preferred embodiment of the present invention will be presented last.

[0040] As shown in figure 2, prior to the implementation of the control method, data on the overall efficiency R1, the efficiency R2 of the fuel cell 2 and the efficiency R4 of the compressor 4 are stored in any storage member such as the valve actuator 7 of the regulating valve 6 or alternatively in a database of a computer. Indeed, the efficiency data R1, R2, R4 are in the form of variables quantifying the energy performance of the system under consideration, i.e. its energy production and / or its energy cost, as a function of one or more parameters. According to a preferred embodiment of the invention, the efficiency data (or data) R1, R2, R4 are in the following form: - the power generated divided by the power consumed by the system under consideration; and / or - deviation from a given maximum efficiency of the system under consideration; and / or - The power generated / consumed by the system under consideration.

[0041] Of course, one or more of the efficiency data R1, R2, R4 may be in the form of other quantification variables of energy performance than those mentioned.

[0042] According to a preferred embodiment of the invention, the efficiency data R1, R2, R4 are further in the form of a theoretical and / or experimentally derived model that depends on one or more parameters. As shown in Figure 3, the efficiency R4 of the compressor 4 varies depending on, and more precisely inversely proportional to, the compression ratio A of the compressor 4. By definition, the compression ratio A of the compressor 4 is governed by the relationship: A=P int / P ext Therefore, the efficiency R4 of the compressor 4 is calculated by multiplying the external pressure P ext If the internal pressure P int 3, the efficiency R2 of the fuel cell 2 varies inversely with respect to the internal pressure P int Needless to say, in the model of the efficiency R2 of the fuel cell 2 and / or the compressor 4, additional parameters can be taken into account, such as the oxygen content in the cathode circuit 3, with respect to the efficiency R2 of the fuel cell 2, as will be explained below.

[0043] As shown in Fig. 3, the overall efficiency R1 designates the efficiency of the electricity generating system 1, defined above as an assembly of the fuel cell 2 and the associated elements enabling its operation. In this example, the electricity generating system 1 is considered to be uniquely formed by the fuel cell 2 and the compressor 4. The overall efficiency R1 therefore varies depending on, and in fact proportionally to, the efficiency R2 of the fuel cell 2 and the efficiency R4 of the compressor 4. Preferably, the overall efficiency R1 corresponds to the quotient of the power generated by the fuel cell 2 divided by the power consumed by the compressor 4.

[0044] Of course, other elements can be added to the electricity generating system 1, such as a cooling circuit 9 for the fuel cell 2, as explained below. Preferably, the relevant elements selected are those whose energy consumption depends on the operating conditions of the fuel cell 2, in particular the internal pressure P int Also preferably, the relevant element selected is one in which the energy consumption is significant compared to the energy production of the fuel cell 2.

[0045] As shown in Figs. 2 and 3, the control method is ext It starts with a step E1 of measuring the external pressure P. In this example, the measuring step E1 is carried out by a measuring element 8, preferably in the form of a pressure sensor, connected to the valve actuator 7 of the regulating valve 6. Alternatively, ext can also be measured indirectly, for example from an aircraft altimetry sensor. At the end of the measurement step E1, the external pressure P ext The measurement result is transmitted to the valve actuator 7.

[0046] 2 and 3, the set internal pressure P for the regulating valve 6 is int * According to a first embodiment shown in FIG. 4A, the determining step E2 comprises: - Test internal pressure P T Test efficiency R of fuel cell 2 from T The step E2-1 of calculating the test internal pressure P T The measured external pressure P ext and a predetermined test compression ratio A belonging to the compression range B. T and the calculating step E2-1, - Test efficiency of electrochemical device 2 R T The incremented new test compression ratio A belongs to the compression range B as long as it is less than a predetermined minimum efficiency threshold S1. T From the test efficiency R T A new step E2-2 to calculate

[0047] Therefore, the set internal pressure P determined during the decision step E2 int * is the test efficiency R T The test internal pressure P at which the minimum efficiency threshold S1 is observed T Corresponds to.

[0048] In practice, as shown in FIGS. 4A and 4B, the calculation step E2-1 is carried out by calculating a predetermined test compression ratio A, which belongs to the compression range B of the compressor 4. T Preferably, the test compression ratio A Tis chosen low to correspond to a low energy consumption of the compressor 4 and therefore a high efficiency R4 of the compressor 4, R4 = f(A T )>S4. S4 specifies the minimum efficiency threshold of compressor 4, and is preferably no more than 50% smaller than the maximum efficiency of compressor 4. Also, preferably, the test compression ratio A T is selected to be less than the median of the compression range B.

[0049] As shown in FIGS. 4A and 4B, during calculation step E2-1, the test efficiency R T The test internal pressure P associated with T But in reality, it's a relationship :P T =R T ×P ext The measured external pressure P ext The test efficiency of fuel cell 2, R T is a part of the fuel cell 2 with a given efficiency R2 and a test internal pressure P T So, in fact, the relationship: R T =R2=g(P T In the example of Figure 4B, the obtained test efficiency R T is lower than the minimum efficiency S1 of the fuel cell 2, therefore a new calculation step E2-2 is performed and a new test compression ratio A T is incremented by an increment ε (see FIG. 4A).

[0050] FIG. 4C shows the new compression ratio A, which is actually performed in the same way as the previous calculation step. T In the example of FIG. 4C, the test efficiency R obtained during calculation step E2-2 is T is greater than the minimum efficiency threshold S1. Therefore, the new calculation steps E2-1 and E2-2 are not performed, and the set internal pressure P int * is the final test internal pressure P calculated during calculation step E2-2 in this example. T Of course, the number of calculation steps E2-1, E2-2 is arbitrary, in particular the selected test compression ratio A T, the increment e, and the minimum efficiency threshold S1. Preferably, the minimum efficiency threshold S1 of the fuel cell 2 is selected to be no more than 50% below the maximum efficiency of the fuel cell 2.

[0051] 2 and 3, at the end of the decision step E2, the set internal pressure P int * 2, the determination step E2 is performed by the valve actuator 7, but it goes without saying that it can be performed by any computing element connected to the valve actuator 7 and a member for storing predetermined data. int * This is achieved by adjusting the passage section of the regulating valve 6 so as to obtain the set internal pressure P int * allows both an improvement in the electricity production of the fuel cell 2 and a limitation in the power consumption of the compressor 4. Preferably, such a control method is carried out by monitoring the external pressure P, preferably measured several times during the flight of the aircraft. ext This is performed for every change in altitude that affects the

[0052] Advantageously, the set internal pressure P int * is determined incrementally, which satisfies the minimum efficiency target S1 while reducing the consumption of the compressor 4.

[0053] FIG. 5A shows a second embodiment of the invention which differs from the previous embodiment in that the decision step E2 comprises: - Measured external pressure P ext and the range of allowable internal pressure PP from the compression range B A and a step E2-A of calculating - Measured external pressure P ext But the internal pressure P int It allows to define the overall efficiency R1 according to the range of permissible internal pressure PP A Step E2-B of maximizing the overall efficiency R1 over

[0054] Therefore, the set internal pressure P int * corresponds to the allowable internal pressure at which the overall efficiency R1 is maximum.

[0055] More precisely, with reference to FIGS. 5B and 5C, the range of permissible internal pressures PP determined during calculation step E2-A A Relationship:PP A =P ext ×B. Also, the measured external pressure P ext is the efficiency R4 of the compressor 4, and the internal pressure P int Thus, at the end of the calculation step E2-A, the efficiency R4 of the compressor 4 and the efficiency R2 of the fuel cell 2 are both dependent on the internal pressure P int Therefore, the overall efficiency R1 depends on the internal pressure P int Furthermore, the range of allowable internal pressure PP A It is possible to define the interval that can maximize the overall efficiency R1.

[0056] As shown in FIGS. 5B and 5C, the maximization stage E2-B is performed from the overall efficiency R1, and the range of allowable internal pressures PP A Set the internal pressure P int * This allows the determination of

[0057] 6A and 6B, according to a preferred embodiment of the present invention, the anode circuit 10 of the fuel cell 2 is also pressure-dependent. More precisely, as shown in FIG. 6A, downstream of the anode circuit 10 is installed a valve 11 that regulates the internal pressure P10 of the anode circuit 10, which will be designated hereinafter as the "second regulating valve 11". For the sake of clarity, the regulating valve 6 of the cathode circuit 3 will be designated here for its part as the "first regulating valve 6". As shown in FIG. 6A, the second regulating valve 11 regulates the second set internal pressure P10 in the anode circuit 10. *To obtain this, in this example, it is provided with a variable passage section controlled by the same valve actuator 7 as that of the first regulating valve 6. Here, for clarity, the set internal pressure P of the first regulating valve 6 int * is designated as "the first set internal pressure P int * ".

[0058] As shown in FIG. 6B, the control method further includes a step E4 of controlling the second regulating valve 11 so as to reach the second set internal pressure P10 * , and the second set internal pressure P10 * is: |P10 * -P int * | < S2 is verified, where S2 designates a predetermined maximum pressure fluctuation threshold value. Thereby, in order to increase the service life of the fuel cell 2, the pressure difference between the cathode circuit and the anode circuit can be limited.

[0059] Referring to FIGS. 7A and 7B, according to another preferred embodiment of the present invention, in order to determine the set internal pressure P of the regulating valve 6 int * , the energy cost of the cooling circuit 9 of the fuel cell 2 is taken into consideration. More precisely, the control method is implemented from predetermined data of the efficiency R9 of the cooling circuit 9 according to the internal pressure P of the cathode circuit 3 int . The overall efficiency R1 depends, in part, on the efficiency R2 of the fuel cell 2, the efficiency R4 of the compressor 4, and the efficiency R9 of the cooling circuit 9. In other words, the electric power generation system 1 is formed by the fuel cell 2, the compressor 4, and the cooling circuit 9.

[0060] Referring to FIGS. 8A and 8B, according to another preferred embodiment of the present invention, a predetermined efficiency R2 of the fuel cell 2 also depends on the oxygen level O in the air of the cathode circuit 3. The control method further includes a step E0 of measuring the oxygen level O in the cathode circuit 3 using a dedicated measuring member 12 in the form of a gas sensor in this example. The measuring step E0 is carried out in parallel with the step E1 of measuring the external pressure P ext , and the efficiency data R2 of the fuel cell 2 is based on the internal pressure Pint Taking into account the oxygen level parameter advantageously allows the set internal pressure P int * It becomes possible to determine more reliably and accurately.

[0061] In conclusion, the internal pressure P proposed in this invention int The adjustment of the internal pressure P corresponds to an unprecedented holistic approach that takes into account not only the electricity generation of the fuel cell 2, or more generally of the electrochemical device, but also the power consumption of its associated components, in particular the compressor 4, and also, for example, the cooling circuit 9. int * advantageously improves the overall efficiency of the electricity generation system based on the electricity production at the output of the fuel cell 2 minus the power consumption of related components such as the compressor 4. Such an overall approach reduces the internal pressure P int This differs from the prior art, where the adjustment of the ratio of the fuel cells 2 was only considered. Such a global approach makes it possible, in particular, to reduce the dimensioning of the compressor 4 and, as a consequence, also the mass and the volume of the compressor 4 installed on board the aircraft.

Claims

1. The internal pressure (P ｉｎｔ ), the fluid circuit (3) is adapted to control a valve (6) for regulating an external pressure (P ｅｘｔ ) and compresses the fluid according to a compression ratio (A) that belongs to a predetermined compression range (B). ｉｎｔ ), the regulating valve (6) is mounted downstream of the fluid circuit (3), and the method includes: ｉｎｔ ＊ ), wherein the method comprises a step (E3) of controlling the regulating valve (6) so as to reach - predetermined data, namely - internal pressure (P ｉｎｔ ) the efficiency (R2) of the electrochemical device (2) as a function of - efficiency (R4) of the compressor (4) as a function of the compression ratio (A), the overall efficiency (R1) depending on the efficiency (R2) of the electrochemical device (2) and the efficiency (R4) of the compressor (4); It was implemented from - External pressure (P ｅｘｔ ) and - The measured external pressure (P ｅｘｔ ) and the compression range (B), the set internal pressure (P ｉｎｔ ＊ ) and A method comprising:

2. Set internal pressure (P ｉｎｔ ＊ ) in a step (E2) of determining - Test internal pressure (P Ｔ ) to the test efficiency (R Ｔ ) is calculated by the step (E2-1), Ｔ ) is adjusted to increase the efficiency (R4) of the compressor (4) by measuring the external pressure (P ｅｘｔ ) and a predetermined compression ratio (At) belonging to a compression range (B), - Test efficiency of electrochemical device (2) (R Ｔ As long as the incremented new test compression ratio (A) is less than a predetermined minimum efficiency threshold (S1), the incremented new test compression ratio (A) is within the compression range (B) of the compressor (4). Ｔ ) to the test efficiency (R Ｔ ) and a new stage (E2-2) of calculating Including, - Set internal pressure (P ｉｎｔ ＊ ) is the test efficiency (R Ｔ ) at which the minimum efficiency threshold (S1) is observed. Ｔ 2. The method of claim 1 , which corresponds to

3. Set internal pressure (P ｉｎｔ ＊ ) in a step (E2) of determining - measured external pressure (P ｅｘｔ ) and the range of allowable internal pressure (PP Ａ ) (E2-A), - measured external pressure (P ｅｘｔ ) due to the internal pressure (P ｉｎｔ The overall efficiency (R1) is redefined according to the allowable internal pressure range (PP Ａ ) and the stage (E2-B) of maximizing the overall efficiency (R1) over Including, - Set internal pressure (P ｉｎｔ ＊ ) is the allowable internal pressure (P) at which the overall efficiency (R1) is maximized. Ａ 2. The method of claim 1 , which corresponds to

4. The efficiency (R2) of the electrochemical device (2) depends on the internal pressure (P ｉｎｔ ) and the efficiency (R4) of the compressor (4) is proportional to the constant external pressure (P ｅｘｔ ) at the internal pressure (P ｉｎｔ 2. The method of claim 1 , wherein the temperature is inversely proportional to the temperature.

5. The electrochemical device (2) has an internal pressure (P ｉｎｔ 2. The method according to claim 1, wherein the cooling circuit (9) has a predetermined efficiency (R9) depending on the efficiency (R1) of the cooling circuit (9), and the overall efficiency (R1) depends on the efficiency (R9) of the cooling circuit (9).

6. 2. The method according to claim 1, wherein the efficiency (R2) of the electrochemical device (2) depends on the oxygen level (O) in the fluid circuit (3), the control method comprising a step (E0) of measuring the oxygen level (O) in the fluid circuit (3), and the determination step (E2) is performed from the measured oxygen level (O).

7. The method of claim 1, wherein the electrochemical device (2) is in the form of a fuel cell.

8. The electrochemical device (2) comprises a second fluid circuit (10) having a second internal pressure (P10) controlled by a second regulating valve (11), and the control method comprises: ＊ -P ｉｎｔ ＊ |<Second set internal pressure for verifying S2 (P10 ＊ 2. The method of claim 1, further comprising a step (E4) of controlling the second regulating valve (11) to reach a predetermined maximum pressure fluctuation threshold, in which (S2) specifies a predetermined maximum pressure fluctuation threshold.

9. 2. The method according to claim 1, wherein an electrochemical device (2) is on board an aircraft to ensure at least part of its supply of electrical energy, and the method is carried out during the flight of the aircraft.

10. The internal pressure (P) of the fluid circuit (3) in the electrochemical device (2) for the implementation of the method according to any one of claims 1 to 9. ｉｎｔ ), wherein the fluid circuit (3) is a module for controlling a valve (6) for regulating an external pressure (P ｅｘｔ ) and compresses the fluid according to a compression ratio (A) that belongs to a predetermined compression range (B). ｉｎｔ ) and the control module is - External pressure (P ｅｘｔ ) a member (8) for measuring - predetermined data, namely - internal pressure (P ｉｎｔ ) the efficiency (R2) of the electrochemical device (2) as a function of - efficiency (R4) of the compressor (4) as a function of the compression ratio (A), the overall efficiency (R1) depending on the efficiency (R2) of the electrochemical device (2) and the efficiency (R4) of the compressor (4); A member for storing the - The measured external pressure (P ｅｘｔ ) and the compression range (B), the set internal pressure (P ｉｎｔ ＊ a computational member configured to determine - Set internal pressure (P ｉｎｔ ＊ a valve actuator (7) for a regulating valve (6) for reaching the A module comprising:

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