DIAGNOSIS OF THE HEALTH STATUS OF A FUEL CELL CHARGING A POWER BATTERY IN A SYSTEM

Abstract

A diagnostic process is implemented in a system comprising an electrical machine powered by a battery that can be recharged by a fuel cell. This process includes a step (10-80) in which it is determined whether at least one chosen condition is met in the system, and, if so, the fuel cell is instructed to deliver a first chosen power output for a first chosen duration. A second power output actually delivered by the fuel cell for a second chosen duration is then determined. Next, information representing the health status of the fuel cell is determined based on these first and second power outputs. If this determined information is less than or equal to a first chosen threshold, at least one alert is generated in the system. Figure 3

Description

Title of the invention: DIAGNOSIS OF THE HEALTH STATUS OF A FUEL CELL RECHARGES A POWER BATTERY OF A SYSTEM Technical field of the invention

[0001] The invention relates to systems comprising at least one fuel cell responsible for recharging a power battery intended to supply electrical energy to an electrical machine, and more specifically the diagnosis of the ongoing health status of such a fuel cell. State of the art

[0002] Some systems, such as for example certain vehicles (possibly automobiles), include at least one power battery which is intended to store electrical energy to power at least one electric machine (possibly a motor), and which is rechargeable by at least one fuel cell.

[0003] It is recalled that a fuel cell is an electrochemical generator producing electrical power (and therefore an electrical voltage) through the oxidation of a reducing fuel (such as dihydrogen) on one electrode, coupled with the reduction of an oxidant (such as oxygen from the air) on another electrode.

[0004] Fuel cells are subject to aging, which gradually alters some of their initial characteristics, such as the electrical power (and therefore the voltage) they can supply to a battery for recharging. Consequently, when the actual State of Health (SOH) of a fuel cell falls below a predefined threshold, it may prevent its system from providing the performance expected by its user. For example, when the system is a vehicle, it may lack power going uphill and / or when loaded, or it may be unable to reach or maintain a speed of 110 km / h on a highway or motorway for an extended period, which can be dangerous.

[0005] It is therefore important to diagnose the health status of a fuel cell in order to be able to schedule preventive maintenance, for example with a view to replacing it.

[0006] Currently, until such a diagnosis has been performed, a default value is used to estimate information that is representative of the fuel cell's health status, and depending on the strategy implemented, this default value is either 100% SOH or 0% SOH. Once the first diagnosis is performed, this value by default is replaced by an estimated value, and the latter is compared to a SOH percentage threshold in order to judge the health status of the fuel cell.

[0007] The diagnosis is usually carried out by asking the fuel cell to supply a predefined current, typically equal to 240 A + / - 10 A, and by measuring for a chosen duration (for example 1 s) the voltage delivered by the fuel cell in response to this request, then estimating the information representative of the state of health by dividing this measured delivered voltage by a target voltage (for example equal to 0.62 V).

[0008] As those skilled in the art know, when the system is a vehicle, depending on the driver's driving style, it frequently happens that the fuel cell cannot (or almost never) supply the predefined current necessary to diagnose its health status. This is often the case, for example, when the driver is a taxi driver in a large urban area. As a result, the diagnosis is rarely, if ever, performed, and therefore the computer that manages the health status is forced to assume that it is still optimal (default value equal to 100% SOH or 0% SOH). Furthermore, such a diagnostic method can lead to the unnecessary (because premature) replacement of a fuel cell considered faulty after a certain period due to the impossibility of performing the necessary diagnostics.

[0009] The invention therefore aims in particular to improve the situation. Presentation of the invention

[0010] In particular, it proposes for this purpose a diagnostic method intended to be implemented in a vehicle comprising an electric machine designed to be supplied with electrical energy by a battery of suitable power to be recharged by a fuel cell.

[0011] This diagnostic method is characterized by the fact that it includes a step in which it is determined whether at least one chosen condition is satisfied in the system, and, if so, the fuel cell is ordered to deliver a first chosen power for a first chosen duration and a second power actually delivered by the fuel cell for a second chosen duration is determined, then information representative of a state of health of the fuel cell is determined as a function of these first and second powers, then, if this determined information is less than or equal to a first chosen threshold, at least one alert is generated in the system.

[0012] Thanks to the invention, the robustness of the diagnosis can now be guaranteed both in terms of frequency of execution and representativeness of the results, thus limiting fuel cell replacements, thereby reducing costs for the manufacturer or system owner and guaranteeing the system user that in the absence of an alert, the latter is able to offer the expected services related to its fuel cell.

[0013] The diagnostic method according to the invention may include other features which may be taken separately or in combination, and in particular:

[0014] - in its step, each chosen condition can be relative to at least one parameter of the power battery, or at least one parameter of the fuel cell, or at least one environmental parameter, or at least one piece of equipment involved in the diagnostics, or at least one fuel cell health indicator;

[0015] - in the presence of the first option, in its step, the (each) parameter of The power battery can be selected from a current state of charge and an internal temperature;

[0016] - also in the presence of the first option, in its step, the (each) parameter the fuel cell can be chosen from an internal temperature, an operating mode selected from at least two fuel cell operating modes, and a duration of fuel cell use since a previous diagnosis;

[0017] - also in the presence of the first option, in its step, the parameter environmental factors can include the current temperature outside the fuel cell;

[0018] - in its step, the information can be determined by dividing the second power determined by the first power chosen;

[0019] - in its step, the first power chosen can be determined as a function of au minus a current state of charge of the power battery and a type of fuel cell;

[0020] - in the presence of the last option, in its step, the first can be determined power chosen based also on at least one auxiliary parameter which is chosen from at least one internal parameter of the power battery, at least one internal parameter of the fuel cell, and at least one environmental parameter.

[0021] The invention also proposes a computer program product comprising a set of instructions which, when executed by processing means, is suitable for implementing a diagnostic method of the type presented above, in a system comprising an electrical machine suitable for being supplied with electrical energy by a power battery suitable for being recharged by a fuel cell, to diagnose an ongoing health status of the fuel cell.

[0022] The invention also proposes a diagnostic device intended to be part of a system comprising an electrical machine suitable for being supplied with electrical energy by a battery of suitable power to be recharged by a fuel cell.

[0023] This diagnostic device is characterized by the fact that it comprises at least one processor and at least one memory arranged to perform the operations of determining whether at least one chosen condition is satisfied in the system, and, if so, requiring the fuel cell to deliver a first chosen power for a first chosen duration and determining a second power actually delivered by the fuel cell for a second chosen duration, then determining information representative of a state of health of the fuel cell as a function of the first and second powers, then, if this determined information is less than or equal to a first chosen threshold, triggering the generation of at least one alert in the system.

[0024] The invention also proposes a system comprising, on the one hand, an electrical machine suitable for being supplied with electrical energy by a battery of suitable power to be recharged by a fuel cell, and, on the other hand, a diagnostic device of the type of that presented above.

[0025] For example, this system can be a vehicle, possibly of the automobile type. Brief description of the figures

[0026] Other features and advantages of the invention will become apparent from an examination of the detailed description below, and the accompanying drawings, in which:

[0027] [Fig. 1] schematically and functionally illustrates an example of an embodiment of a system constituting a vehicle comprising a purely electric powertrain, a power battery associated with a fuel cell, and a diagnostic device according to the invention,

[0028] [Fig.2] schematically and functionally illustrates an example of an embodiment of a management computer comprising an example of an embodiment of a diagnostic device according to the invention,

[0029] [Fig.3] schematically illustrates an example of an algorithm implementing a diagnostic method according to the invention. Detailed description of the invention

[0030] The invention aims in particular to provide a diagnostic method, and an associated diagnostic device DD, intended to allow a diagnosis of the current state of health of a fuel cell PAC responsible for recharging a power battery BP in a system S.

[0031] In what follows, system S is considered, by way of non-limiting example, to be a motor vehicle (such as, for example, a car, as illustrated in [Fig. 1]). However, the invention is not limited to this type of system. It relates to any type of system comprising an electrical machine suitable for being supplied with electrical energy by a battery of suitable power to be recharged by at least A fuel cell, whether static or mobile (such as a vehicle (land, sea (or river), or air). Note that in the case of a static system, the power battery is said to be stationary.

[0032] Furthermore, in what follows, by way of non-limiting example, the fuel cell (FC) is considered to be an electrochemical generator producing electrical power (and therefore an electrical voltage) through the oxidation of dihydrogen (reducing fuel) at one electrode, coupled with the reduction of atmospheric oxygen (oxidant) at another electrode. However, the invention is not limited to this type of fuel cell. It relates, in fact, to any type of fuel cell constituting an electrochemical generator producing electrical power (and therefore an electrical voltage) through the oxidation of a reducing fuel at one electrode, coupled with the reduction of an oxidant at another electrode.

[0033] Furthermore, in what follows, it is considered, by way of non-limiting example, that the power battery BP is intended to supply electrical energy to at least one electric motor ME, and therefore forms part of the powertrain (or powertrain) of the vehicle S. However, the invention is not limited to this application. Indeed, the power battery BP can supply electrical energy to any type of electric machine, motor or non-motor, within its system S.

[0034] Finally, in what follows, by way of non-limiting example, we consider that the powertrain is of the all-electric type (and therefore responsible for providing engine torque exclusively of electrical origin to move the vehicle S). But the powertrain could be of the hybrid type (thermal and electric).

[0035] Schematically represented in [Fig.1], by way of illustration, is a system S (here a land vehicle) comprising a diagnostic device DD according to the invention and a purely electric GMP transmission chain (and therefore comprising (here) a single electric motor machine ME), a power battery BP rechargeable by a fuel cell PAC, a service battery BS, a converter CV, and an on-board network RB.

[0036] The CV converter allows DC / DC (“Direct Current / Direct Current” (direct current / direct current)) and / or AC / DC (“Alternating Current / Direct Current” (alternating current / direct current)) charging. It is therefore responsible for converting a direct or alternating current from a first voltage to a second voltage.

[0037] The RB on-board network is an electrical power supply network to which electrical (or electronic) equipment (or components) that consume electrical energy are coupled.

[0038] The auxiliary battery BS is responsible for supplying electrical power to the on-board network RB, in addition, here, to that supplied by the converter CV powered by the power battery BP via a power electrical network, and sometimes instead, here, of this CV converter. For example, this BS service battery can be configured as a very low voltage type battery (typically 12 V, 24 V, or 48 V). It is rechargeable at least by the CV (current) converter. In the following, we will assume, as a non-limiting example, that the BS service battery is a 12 V lithium-ion type.

[0039] The transmission chain has a GMP which is, here, purely electric and therefore includes, in particular, an electric motor machine ME, and a transmission shaft AT.

[0040] Here, "electric motor ME" means an electric machine arranged to provide an electric motor torque, defined by a torque setpoint, to move the vehicle S when it is supplied with electrical energy by the power battery BP, and possibly to recover regenerative braking torque to decelerate the vehicle S.

[0041] The operation of the GMP (and therefore of the ME electric machine) is supervised by a CS supervisory computer (or an equivalent device).

[0042] The electric drive machine ME is coupled to a motor shaft AM, which is itself coupled to a reduction gear RD (or reduction device), to provide it with electric motor torque by rotational drive when it is supplied with electrical energy from the power battery BP via the power grid. This reduction gear RD is coupled to the transmission shaft AT, which is itself coupled to a first set of drive wheels Tl, here via a differential DV.

[0043] It should be noted that the first axle Tl (here, the motor axle) is located in the front PVV section of the vehicle S, and is therefore referred to hereafter as the front axle. However, in one variant, this first axle Tl could be the second axle T2, which is located in the rear PRV section of the vehicle S, and in another four-wheel-drive variant, the engine torque could be transmitted to both the first Tl and second T2 axles.

[0044] The BP power battery may, for example, comprise electrical energy storage cells, possibly electrochemical (e.g., lithium-ion (or Li-ion) or Ni-MH or Ni-Cd type). Also, for example, the BP power battery may be of the low-voltage type (typically 450 V or 600 V, by way of illustration). But it could also be of the medium-voltage or high-voltage type.

[0045] The control of the operation of the BP power battery is ensured by a CB battery computer, which is notably responsible for estimating its state of charge (or "State of Charge" (or SoC)) according to parameters well known to those skilled in the art.

[0046] As mentioned above, this power battery BP is mainly (or even entirely) recharged by the fuel cell PAC which is associated with an RCR tank storing reducing fuel (here, dihydrogen). This RCR tank It can be supplied with reducing fuel, here by connecting a dedicated connector on the vehicle S to a reducing fuel supply source. The fuel cell is therefore an electrochemical generator producing electrical power (and thus an electrical voltage) through the oxidation (here) of dihydrogen on one electrode, coupled with the reduction (here) of oxygen from the air on another electrode.

[0047] The control of the operation of the fuel cell PAC is ensured by a fuel cell computer CP, which is supervised by a management computer CG (also coupled to the battery computer CB).

[0048] It should be noted that the CV converter can also be charged, here, during the driving phases of the vehicle S, with converting part of the electrical current stored in the power battery BP to supply converted electrical current to the on-board network RB and the auxiliary battery BS (to recharge it).

[0049] It should also be noted that in the example illustrated, but not limited to, in [Fig. 1], the vehicle S also includes a distribution box BD to which the auxiliary battery BS, the converter CV, and the on-board network RB are coupled. This distribution box BD is responsible for distributing the electrical energy stored in the auxiliary battery BS or produced by the converter CV into the on-board network RB to power the electrical components (or equipment) connected to the on-board network RB, according to power demands received (in particular from the powertrain control unit CS).

[0050] As mentioned above, the invention notably proposes a diagnostic method intended to allow the diagnosis of the state of health (or SOH (State Of Health)) of the fuel cell PAC.

[0051] The (diagnostic) method can be implemented at least partially by the diagnostic device DD (illustrated at least partially in Figures 1 and 2), which for this purpose comprises at least one processor PR1, for example of the microprocessor type, and at least one memory MD. This diagnostic device DD can therefore be implemented in the form of a combination of electrical or electronic circuits or components (or "hardware") and software modules (or "software"). By way of example, it could be a microcontroller.

[0052] The MD memory is random access memory (RAM) to store instructions for the implementation by the PR1 processor of at least part of the diagnostic process. The PR1 processor may comprise integrated (or printed) circuits, or several integrated (or printed) circuits connected by wired or wireless connections. An integrated (or printed) circuit is defined as any type of device capable of performing at least one electrical or electronic operation.

[0053] In the example illustrated, but not limited to, in Figures 1 and 2, the diagnostic device DD is part of the management computer CG. This is advantageous because it The latter (CG) manages (or supervises) the fuel cell / power battery pair. However, this is not mandatory. The diagnostic device (DD) could include its own dedicated computer, which is then coupled to the CG management computer, or it could be part of another computer (here embedded) than the CG, such as the fuel cell power unit (CP).

[0054] As illustrated non-limitingly in [Fig.3], the (diagnostic) method according to the invention includes a step 10-80 which is implemented when a diagnosis of the health status of the fuel cell PAC is requested within the system S (for example by the management computer CG).

[0055] Step 10-80 of the method includes a substep 10 in which the diagnostic device DD determines whether at least one selected condition is met in the system S (here, a vehicle). Preferably, and as will be seen later, it is preferable to determine whether several (at least two) selected conditions are met simultaneously in the system S (here, a vehicle).

[0056] If at least one of the chosen conditions is not met, the diagnosis cannot be carried out, and therefore the diagnostic process ends in a sub-step 20 of step 10-80.

[0057] Conversely, if each chosen condition is met (and therefore, in the affirmative), the diagnosis can be performed. Consequently, step 10-80 of the process also includes a substep 40 in which the fuel cell PAC is instructed to deliver (the diagnostic device DD requires that the fuel cell PAC deliver) a first (electrical) power pel for a first chosen duration dl, and a second (electrical) power pe2 actually delivered by the fuel cell PAC is determined (by the diagnostic device DD) for a second chosen duration d2. It will be understood that the first chosen power pel is a setpoint that is transmitted to the fuel cell computer CP, and that the second power pe2 is determined during the second duration d2, which is included within the first duration dl.

[0058] Step 10-80 of the process also includes a substep 50 in which one (the diagnostic device DD) determines information ies which is representative of the state of health of the fuel cell PAC, as a function of the first power chosen pel and the second power pe2 determined.

[0059] Step 10-80 of the process also includes a substep 80 in which, if this determined information ies is less than or equal to a first threshold, if chosen, at least one alert is generated in the system S (here, a vehicle). In this substep 80, the new determined information ies is stored in place of the old information by the diagnostic device DD, and the process terminates. This storage takes place in a memory of the diagnostic device DD or the control unit CG.

[0060] It will be understood that if the determined information ies is greater than the first threshold, this means that the fuel cell PAC's health status is satisfactory (and therefore does not require maintenance by an after-sales service). Consequently, and as illustrated in [Fig. 3], step 10-80 of the process includes a substep 70 in which the diagnostic device DD stores the new determined information ies in place of the old information, and the process ends. This storage takes place in a memory of the diagnostic device DD or the control unit CG.

[0061] By verifying that at least one condition is met, the diagnosis can now be performed robustly and the information ies (representative of the fuel cell's health status) can be accurately estimated. The robustness of the diagnosis can therefore be guaranteed, both in terms of frequency of execution and the representativeness of the results, thus limiting fuel cell replacements. This reduces the costs incurred by the manufacturer or owner of system S (due to premature fuel cell replacement) and assures the user of system S that, in the absence of any alerts, the system (S) is capable of providing the expected performance from its fuel cell.

[0062] For example, the initial electric power output (PEL) can be between 43 kW and 47 kW. As an illustrative example, the initial electric power output (PEL) can be 45 kW. However, other values ​​for the initial electric power output (PEL) can be used. For example, this initial electric power output (PEL) can be chosen during the development or testing phase (here) of a vehicle similar to vehicle S.

[0063] Also, for example, the first duration dl can be between 200 s and 400 s. As an illustrative example, the first duration dl can be equal to 300 s. But other values ​​for the first duration dl can be used. For example, this first duration dl can be chosen during the development or testing phase (here) of a vehicle similar to vehicle S.

[0064] Also, for example, the second duration d2 can be between 40 s and 80 s. As an illustrative example, the second duration d2 can be equal to 60 s. But other values ​​for the second duration d2 can be used. For example, this second duration d2 can be chosen during the development or testing phase (here) of a vehicle similar to vehicle S. Alternatively, the second duration d2 can be a chosen percentage of the first duration d1.

[0065] Also, for example, when the determined information ies is a percentage, the first threshold si can be between 60% and 70%. As an illustrative example, the first threshold si can be equal to 65%. But other values ​​of the first threshold si can be used. For example, this first threshold si can be chosen during the development or testing phase (here) of a vehicle similar to vehicle S.

[0066] It should be noted that the first threshold, if used, is not necessarily predefined (and therefore fixed). Indeed, it may vary depending on at least one parameter, such as (but not limited to) the current state of charge ecbp of the power battery BP or the current temperature tec outside the fuel cell PAC.

[0067] Also, for example, in substep 10 of step 10-80, each selected condition may relate to at least one parameter of the power battery BP, or to at least one parameter of the fuel cell PAC, or to at least one environmental parameter, or to at least one piece of equipment involved in the diagnostics, or to at least one health indicator of the fuel cell PAC. It should be noted that this list is not exhaustive.

[0068] Thus, for example, in substep 10 of step 10-80, each parameter of the power battery BP can be chosen from its current state of charge ecbp and its internal temperature tibp. In this case, the condition relating to the current state of charge ecbp of the power battery BP is satisfied only when this current state of charge is below a second chosen threshold s2 (i.e., ecbp < s2). Indeed, when the fuel cell delivers the second electrical power pe2 (due to the first electrical power pel required), the power battery BP must be able to receive this second electrical power pe2 and therefore recharge. To achieve this, it is preferable that the current state of charge ecbp of the power battery BP be below the second threshold s2, so that the latter (BP) is able to receive the second electrical power pe2.If this condition is not met, the diagnosis is postponed until it is met, and in the meantime it is also preferable to ask the CG management computer to limit the power delivered by the fuel cell PAC while the power battery BP discharges.

[0069] For example, when the current state of charge ecbp is a percentage of the maximum state of charge of the power battery BP, the second threshold s2 can be between 30% and 50%. As an illustrative example, the second threshold s2 can be equal to 40%. However, other values ​​for the second threshold s2 can be used. For example, this second threshold s2 can be chosen during the development or testing phase (here) of a vehicle similar to vehicle S.

[0070] Furthermore, the condition relating to the internal temperature tibp of the power battery BP is satisfied only when this internal temperature tibp is less than a third threshold s3 chosen (i.e. tibp < s3).

[0071] For example, the third threshold s3 can be between 40°C and 60°C. As an illustrative example, the third threshold s3 can be equal to 50°C. However, other values ​​for the third threshold s3 can be used, as it depends primarily on the type (or design) of the power battery BP. By For example, this third threshold s3 can be chosen during the development or testing phase (here) of a vehicle similar to vehicle S.

[0072] Also, for example, in substep 10 of step 10-80, each parameter of the fuel cell PAC can be chosen from its internal temperature tipac, the operating mode that has been selected by the user from among at least two operating modes of the fuel cell PAC, and the duration of use of the fuel cell PAC since a previous diagnosis.

[0073] In this case, the condition relating to the internal temperature tipac of the fuel cell PAC is satisfied only when this internal temperature tipac is within a range of chosen temperatures (defined by a minimum temperature and a maximum temperature).

[0074] For example, the minimum temperature can be between -20°C and -10°C, and the maximum temperature can be between +75°C and +80°C. As an illustrative example, the minimum temperature can be -15°C, and the maximum temperature can be +78°C. However, other minimum and maximum temperature values ​​can be used, as these depend primarily on the type (or design) of the fuel cell. For example, these minimum and maximum temperatures can be chosen during the development or testing phase (here) of a vehicle similar to vehicle S.

[0075] Furthermore, the condition relating to the selected operating mode of the fuel cell is satisfied only when this operating mode is equal to one of the predefined operating modes contained in a predefined list and compatible with the performance of the diagnosis.

[0076] On the other hand, the condition relating to the duration of use of the fuel cell since its previous diagnosis is satisfied only when this duration of use is greater than a fourth threshold s4 chosen (i.e. dupac > s4).

[0077] For example, the fourth threshold s4 can be between 40 and 60 hours. As an illustrative example, the fourth threshold s4 can be 50 hours. However, other values ​​for the fourth threshold s4 can be used, as it depends primarily on the type (or design) of the fuel cell. For example, this fourth threshold s4 can be chosen during the development or testing phase (here) of a vehicle similar to vehicle S.

[0078] Also, for example, in substep 10 of step 10-80, the (one) environmental parameter can be the current temperature tec outside the fuel cell PAC. In this case, the condition relating to the outside temperature tec is satisfied only when the latter (tec) is greater than a fifth chosen threshold s5 (i.e., tec > s5).

[0079] For example, the fifth threshold s5 can be between +5°C and +15°C. As an illustrative example, the fifth threshold s5 can be equal to +10°C. However, other values ​​for the fifth threshold s5 can be used. For example, this fifth threshold s5 can be chosen during the development or testing phase (here) of a vehicle similar to vehicle S.

[0080] Also, for example, in substep 10 of step 10-80, a diagnostic component may be a sensor used in at least one of the conditions (such as, for example, a tiBP internal temperature sensor of the power battery or a tipac internal temperature sensor of the fuel cell) or to determine whether at least one of the conditions is met. In this case, the condition is met only when each of the aforementioned components is functioning correctly.

[0081] Also, for example, in substep 10 of step 10-80, the condition relating to a fuel cell health indicator is satisfied only when that health indicator has a predefined value (for example, a boolean having a specific value).

[0082] Also, for example, in substep 50 of step 10-80, the diagnostic device DD can determine the information ies by dividing the second determined electrical power pe2 by the first selected electrical power pel (i.e., ies = pe2 / pel). In this case, the information ies is a percentage. However, other mathematical formulas with the first selected electrical power pel and the second determined electrical power pe2 as parameters can be used, provided they yield a result that is representative of the health status of the fuel cell.

[0083] Also, for example, and as illustrated non-limitingly in [Fig. 3], step 10-80 may also include a substep 30 in which the diagnostic device DD can determine the first selected electrical power pel based on at least the current state of charge ecbp of the power battery BP and the type (or design) of the fuel cell PAC. But in an alternative embodiment, the first electrical power pel could be predefined.

[0084] It should be noted that in order to guarantee safe recharging of the power battery BP and optimal use of the fuel cell PAC, in substep 30 on (the diagnostic device DD) can determine the first selected electrical power pel as a further function of at least one auxiliary parameter which is selected from at least one internal parameter of the power battery BP, at least one internal parameter of the fuel cell PAC, and at least one environmental parameter. Each auxiliary parameter can be used in conjunction with the current state of charge ecbp of the power battery BP and the type (or design) of the fuel cell. fuel cell PAC to directly determine the first electrical power chosen pel, or as part of a correction (or adjustment) of the electrical power chosen pel previously determined with the current state of charge ecbp of the power battery BP and the type (or design) of the fuel cell PAC.

[0085] For example, when an auxiliary parameter is an internal parameter of the BP power battery, it may be its internal temperature tibp (this is intended to limit the lithium plating phenomenon as much as possible).

[0086] Also, for example, when an auxiliary parameter is an internal parameter of the fuel cell PAC, it may be its internal temperature tipac.

[0087] Also, for example, when an auxiliary parameter is an environmental parameter, it may be the current outside temperature.

[0088] It should also be noted that each generated alert can be intended for the CG management computer and / or the user of the S system (here a vehicle).

[0089] Preferably, when the determined information ies is equal to the first threshold si (i.e. ies = si), a single alert can be generated for the management computer CG only, in order to inform it that maintenance will soon have to be carried out (in this case the user of the system S is not informed in parallel with the management computer CG).

[0090] When the determined information ies is below the first threshold si (i.e., ies < si), a first alert can be generated for the control unit CG and a second alert for the user of system S. The first alert is intended to inform the control unit CG that maintenance must be carried out very soon. The second alert, intended for the user of system S, can be given by the illumination of an indicator light (possibly dedicated) of system S (for example, on the instrument panel in the case of a vehicle) or by the generation of at least one message. In the case of a message, it can be a text message displayed on at least one screen of system S (for example, on the instrument panel or a central instrument cluster in the case of a vehicle) or on the screen of a smartphone belonging to the user of system S and / or an audible message broadcast by at least one speaker of system S or of that smartphone.This warning message may indicate its cause.

[0091] It should also be noted that it is possible to record at least one fault code representing an insufficient (or soon-to-be insufficient) state of health, in order to facilitate the work in an after-sales service department. It should be noted that the storage of each fault code can, for example, be done in a (possibly read-only) memory of the CG control unit or in a control unit dedicated to storing fault codes in the S system.

[0092] It will also be noted, as illustrated non-limitingly in [Fig.2], that the CG management computer (or the DD diagnostic device computer) may also include a mass memory MM1, in particular to store each parameter of the power battery BP involved in the diagnosis or verification of a condition, each parameter of the fuel cell PAC involved in the diagnosis or verification of a condition, each environmental parameter involved in the diagnosis or verification of a condition, each piece of information relating to equipment involved in the diagnosis or verification of a condition, and each fuel cell PAC health indicator involved in the diagnosis or verification of a condition, as well as any intermediate data involved in all its calculations and processing.Furthermore, this management computer CG (or the diagnostic device computer DD) may also include an input interface IE for receiving at least the second determined electrical power pe2, each parameter of the power battery BP involved in the diagnosis or verification of a condition, each parameter of the fuel cell PAC involved in the diagnosis or verification of a condition, each environmental parameter involved in the diagnosis or verification of a condition, each piece of information relating to equipment involved in the diagnosis or verification of a condition, and each health indicator of the fuel cell PAC involved in the diagnosis or verification of a condition, for use in calculations or processing, possibly after having shaped and / or demodulated and / or amplified them, in a manner known per se, by means of a digital signal processor PR2.Furthermore, this CG management computer (or the DD diagnostic device computer) may also include an IS output interface, notably to generate at least (or trigger the delivery of at least) one alert in the S system (here a vehicle), and a possible message (or command) to record at least one fault code.

[0093] It will also be noted that the invention also proposes a computer program product (or computer program) comprising a set of instructions which, when executed by processing means of the type of electronic circuits (or hardware), such as for example the PR1 processor, is suitable for implementing the diagnostic process described above to diagnose the current state of health of the fuel cell PAC of system S (here a vehicle).

Claims

Demands

1. Diagnostic method for a system (S) comprising an electrical machine (EM) suitable for being supplied with electrical energy by a power battery (PM) suitable for being recharged by a fuel cell (FC), characterized in that it comprises a step (10-80) in which it is determined whether at least one chosen condition is satisfied in said system (S), and, if so, said fuel cell (FC) is instructed to deliver a first chosen power for a first chosen duration and a second power actually delivered by said fuel cell (FC) for a second chosen duration is determined, then information representative of a state of health of said fuel cell (FC) is determined as a function of said first and second powers, then, if said determined information is less than or equal to a first chosen threshold, at least one alert is generated in said system (S).

2. Method according to claim 1, characterized in that in said step (10-80) each condition chosen is related to at least one parameter of said power battery (PB), or to at least one parameter of said fuel cell (FC), or to at least one environmental parameter, or to at least one piece of equipment involved in said diagnosis, or to at least one health indicator of said fuel cell (FC).

3. Method according to claim 2, characterized in that in said step (10-80) said power battery parameter (BP) is chosen from a current state of charge and an internal temperature.

4. Method according to claim 2, characterized in that in said step (10-80) said parameter of said fuel cell (FC) is chosen from an internal temperature, an operating mode selected from at least two operating modes of said fuel cell (FC), and a duration of use of said fuel cell (FC) since a previous diagnosis.

5. A method according to any one of claims 1 to 4, characterized in that in said step (10-80) said information is determined by dividing said second power determined by said first power chosen.

6. A method according to any one of claims 1 to 5, characterized in that in said step (10-80) said first power is determined as a function of at least one current state of charge of said power battery (PB) and of a type of said fuel cell (FC).

7. Method according to claim 6, characterized in that in said step (10-80) said first power selected is determined as a further function of at least one auxiliary parameter selected from at least one internal parameter of said power battery (PB), at least one internal parameter of said fuel cell (FC), and at least one environmental parameter.

8. Product computer program comprising a set of instructions which, when executed by processing means, is suitable for implementing the diagnostic process according to any one of claims 1 to 7, in a system (S) comprising an electrical machine (ME) suitable for being supplied with electrical energy by a power battery (BP) suitable for being recharged by a fuel cell (FC), for diagnosing an ongoing health status of said fuel cell (FC).

9. Diagnostic device (DD) for a system (S) comprising an electrical machine (EM) suitable for being powered by a power battery (PB) suitable for being recharged by a fuel cell (FC), characterized in that it comprises at least one processor (PR1) and at least one memory (MD) arranged to perform the operations of determining whether at least one chosen condition is met in said system (S), and, if so, requiring said fuel cell (FC) to deliver a first chosen power for a first chosen duration and determining a second power actually delivered by said fuel cell (FC) for a second chosen duration, then determining information representative of a health status of said fuel cell (FC) as a function of said first and second powers, then, if said determined information is less than or equal to a first chosen threshold,to trigger the generation of at least one alert in said system (S).

10. System (S) comprising an electrical machine (ME) suitable for being supplied with electrical energy by a power battery (BP) suitable for being recharged by a fuel cell (FC), characterized in that it further comprises a diagnostic device (DD) according to claim 9.

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