MOTOR VEHICLE COMPRISING THERMAL MANAGEMENT MEANS FOR A FUEL CELL

Abstract

The invention relates to an electric motor vehicle, comprising control means for operating a cooling circuit (100) of the fuel cell assembly (1), comprising, in a first branch (110), a first pump (20) pushing a coolant through the cell assembly (1) to a first valve (50) allowing or preventing the circulation of the coolant between the first branch (110), a second branch (120) comprising a radiator (2), and a thermal storage branch (140) suitable for storing, releasing, or distributing heat, upstream of a second pump (40) whose direction of flow is controlled by the control means, the cooling circuit (100) comprising, downstream of the radiator (2) and the second pump (40), a second valve (30) controlled by the control means, upstream of the first pump (20). Figure 2

Description

Title of the invention: MOTOR VEHICLE COMPRISING MEANS FOR THERMAL MANAGEMENT OF A FUEL CELL

[0001] The invention relates to an electric or hybrid motor vehicle, comprising a fuel cell comprising an assembly of cells, and a cooling circuit arranged for cooling said assembly of cells, and control means arranged to control said fuel cell and said cooling circuit on the basis of information from sensors included in said control means.

[0002] The invention relates to electric or hybrid motor vehicles, comprising a fuel cell, also called FCEV (from the English “fuel cell electric vehicle”).

[0003] The thermal power dissipated by a proton exchange membrane fuel cell, also called a polymer electrolyte membrane fuel cell (PEMFC, from the English "proton exchange membrane fuel cells" or "polymer electrolyte membrane fuel cells") is significant and of the same order of magnitude as (and sometimes exceeding) the electrical power supplied.

[0004] Thermal management is a crucial function affecting the performance, reliability and durability of a fuel cell for automotive applications.

[0005] Thermal adaptation of a PEMFC fuel cell to a vehicle must address two major constraints. First, the exhaust gases from the cell carry away only a small portion of the emitted heat (barely 5%), so that virtually all of the generated thermal power must be dissipated in the PEMFC fuel cell's cooling system. Second, the temperature of the PEMFC fuel cell must be controlled between 60 and 80°C for performance and durability.

[0006] In summary, the cooling system of the PEMFC fuel cell must dissipate a high thermal power, often greater than that dissipated in its cooling circuit by the thermal engine of equivalent output power, under a temperature difference, between the ambient air and the coolant at the radiator inlet, which is much lower.

[0007] Satisfying the cooling requirement of a low-temperature PEMFC fuel cell, more suitable for automotive applications than their high-temperature variants which pose problems of temperature rise and maintenance, cold start, corrosion and mechanical degradation, requires the combination of several elements:

[0008] - several radiators are necessary (where the cooling of an engine thermal only requires one), with a surface area and thickness 2 to 4 times greater than those of the radiators used to cool thermal engines of equivalent power. However, such radiators are much larger, heavier, more expensive and difficult to install in the vehicle, and significantly degrade, due to their greater wetted surface area, the cleanliness and electrical conductivity of the coolant used in the cooling circuit of the PEMFC fuel cell and the volume of which must be limited, given the price of this coolant which is specific to the PEMFC application requiring very low conductivity and very high cleanliness;

[0009] - much larger air inlet and extraction surfaces. However, such inlets and air extractions degrade the vehicle's aerodynamic capture drag, and therefore its energy consumption;

[0010] - as well as electric pumps for circulating liquid flow in the circuit of cooling of the PEMFC fuel cell and the motor-fan units (FMUs) blowing or sucking ambient air through such exchangers, to be sized accordingly. However, such components (electric pumps, FMUs) add to the difficulties of installation, weight and cost of FCEV vehicles, and require high electrical power to control both (and often at the same time) large flow rates of liquid in the cooling circuit of the PEMFC fuel cell and the motor-fan units (FMUs) blowing or sucking, with high airflow power, the ambient air through such exchangers. Such very high electrical power (several kW) impacts the sizing of the vehicle's electrical architecture (these components must then be powered by the vehicle's 200 to 800V network) and deteriorates the efficiency of the complete system.

[0011] Furthermore, phase change materials (PCM) are a solution of thermal management known to store the heat emitted by a system when it is hot to return it to it when it is cold again, several hours or a few days later, to improve its thermal insulation, promote or enable starting and / or accelerate its temperature rise to more quickly reach its optimal operating temperature. However, adapting a PCM thermal energy storage system to the vehicle often requires a large volume, while it is only used for a very limited phase of the vehicle's life.

[0012] Document US11139491B2 thus describes a thermal management system for a fuel cell vehicle comprising a first line comprising a coolant pump and a stack or pile of fuel cells, a second line comprising a coolant heater and a phase change material (PCM) and connected to the first line to form a first loop in which a coolant pump, the stack, the coolant heater and the PCM are arranged, a third line comprising a radiator and connected to the first line to form a second loop in which a water pump, the stack and a radiator are arranged, and comprising an opening and closing valve opening and closing each of the first line, the second line and the third line to allow the coolant to circulate in at least one of the first loop and the second loop, wherein the PCM is configured to be subjected to a heat exchange with each of the coolant heater and the coolant, and wherein the coolant heater comprises a heating core configured to heat the coolant, a heat pipe configured to thermally connect the heating core and the PCM,and a metal coil wound around the heating core and an outer circumferential portion of the second line to thermally connect the heating core and the second line.

[0013] The objective of the present invention is to overcome these drawbacks by proposing to equip the vehicle with a cooling system, which is deliberately sized to cover only the majority, and not all, of the cooling needs of the PEMFC fuel cell. The invention implements a particular device, for example based on phase change material PCM, in severe uses for which the vehicle's cooling system is undersized, to store the excess heat emitted by the PEMFC fuel cell and which the undersizing of the vehicle's cooling system cannot evacuate. When the conditions of use of the vehicle become less demanding for its thermal system, the stored heat is released into the cooling circuit of the PEMFC fuel cell to be dissipated to the outside air.If relevant, this heat is retained longer and returned to the vehicle for various other purposes.

[0014] To achieve this objective, the invention proposes an electric or hybrid motor vehicle, comprising a fuel cell comprising an assembly of cells, and a cooling circuit arranged for cooling said assembly of cells, and control means arranged to control said fuel cell and said cooling circuit on the basis of information from sensors included in said control means.

[0015] According to the invention, said cooling circuit comprises, in a first branch comprising said assembly of cells, a first pump upstream of said assembly of cells, arranged to move a cooling liquid through said assembly of cells, said first branch opening, downstream of said as assembly of cells, on a first valve controlled by said control means and arranged to authorize or prohibit the circulation of said coolant between said first branch, a second branch comprising at least one radiator cooperating with at least one motor-fan unit, and a thermal reserve branch which comprises a thermal reserve capable of storing, releasing, or restoring heat, upstream of a second pump whose direction of circulation is controlled by said control means, said cooling circuit comprising, downstream of said at least one radiator and said second pump, a second valve controlled by said control means, upstream of said first pump.

[0016] Thanks to the invention, it is possible to ensure efficient cooling of the fuel cell in all temperature configurations to which the vehicle or its constituents are subjected. The second valve and the second pump allow, in combination with the first valve and the first pump, all circulations of coolant adapted to the thermal configurations within the vehicle and in its environment.

[0017] Advantageously, said cooling circuit comprises a third branch whose inlet is arranged downstream of said assembly of cells and upstream of said first valve, and whose outlet joins said second valve, said third branch comprising at least one liquid / liquid type heat exchanger, between said coolant of said cooling circuit and another coolant of at least two other fluid loops of said vehicle.

[0018] Thus the cooling circuit takes advantage of the presence of other cooling or heating circuits in the vehicle, which makes it possible to reduce the size of the radiator and to use, by its removal from the thermal reserve and its restitution, the heat previously stored there.

[0019] Advantageously, said vehicle comprises an electrical energy storage system, and a device arranged to ensure the heating and cooling of said electrical energy storage system and which constitutes one of said fluid loops.

[0020] The cooling device of the electrical energy storage system thus participates in the overall cooling system.

[0021] Advantageously, said vehicle comprises a heating system arranged to provide heating of the passenger compartment of said vehicle and which constitutes one of said fluid loops.

[0022] This way, the fuel cell cooling circuit is used to reduce the high winter energy requirement for heating the passenger compartment. This configuration makes it possible to optimize the entire thermal management.

[0023] Advantageously, said cooling circuit comprises a pressure-controlled valve, in said first branch at the inlet of which first pump, opposite said assembly of cells.

[0024] The closed position of the valve makes it possible to avoid parasitic circulation of coolant within the cooling circuit, in particular within the cell assembly.

[0025] Advantageously, said cooling circuit comprises a coolant reservoir, arranged to ensure the functions of degassing said cooling circuit, thermal expansion of the liquid and pressurization of the cooling circuit at the inlet of said first pump.

[0026] Thus the reservoir makes it possible to cope with variations in volume and pressure of the coolant.

[0027] Advantageously, said reservoir is upstream of said valve, so that closing of said valve prevents said coolant from passing through said reservoir.

[0028] This controls the flow of coolant through the reservoir.

[0029] Advantageously, said reservoir provides said coolant with a first inlet which opens above ground into said reservoir from an auxiliary coolant outlet of said cell assembly via an auxiliary branch that comprises said cooling circuit and which comprises a deionizer arranged to preserve a very low electrical conductivity of said coolant within said cooling circuit, and a second inlet opening underwater into said reservoir, from an auxiliary coolant outlet that comprises said radiator and which is arranged within said radiator so that this portion of liquid flow which comes from it has not exchanged calories through the radiator with the outside air moved through said radiator by the movement of said vehicle and / or the activation of said motor-fan unit,said reservoir being arranged to provide an outlet for said coolant to the suction of said first pump, previously through said valve.

[0030] These provisions make it possible to limit the heating of the coolant and to preserve its very low electrical conductivity.

[0031] Advantageously, said thermal reserve comprises a device for storing and releasing or restoring heat based on PCM phase change material.

[0032] This takes advantage of the latent heat of change of state to optimize cooling, while limiting the volume of the installation.

[0033] Advantageously, said cooling circuit comprises, on said first branch, immediately upstream of said assembly of cells, a particle filter arranged to protect the constituent parts of said assembly of cells.

[0034] The cell assembly is thus well protected against any pollution.

[0035] The invention will be further detailed by the description of non-limiting embodiments, and on the basis of the appended figures illustrating variants of the invention, in which: - [Fig.l] schematically illustrates a motor vehicle according to the invention, comprising control means, a fuel cell known as PEMFC comprising an assembly of cells also called a “stack”, and a cooling circuit for this fuel cell; this vehicle also comprises a vehicle electrical energy storage system known as EESS, and a passenger compartment heating system; - [Fig.2] schematically illustrates the architecture of the cooling circuit implemented by the invention to ensure thermal management of the PEMFC proton exchange membrane fuel cell and the vehicle; - [Fig.3] schematically illustrates, in table form, eleven main operating modes of the cooling circuit, and a derived mode; this table explains the configurations taken by different components in their position represented in [Fig.2]: a first valve, a second valve, a second pump, a first pump, and a flap, and the orientation of the coolant flows imposed or prohibited by these different components for these different operating modes of the cooling circuit; this table indicates, for each mode, whether each pump is active (ON) or not (OFF), and the direction of circulation of the pump concerned.

[0036] The invention relates to an electric or hybrid motor vehicle 1000, comprising a fuel cell 500 with a proton exchange membrane also called PEMFC, and a cooling circuit 100 of this fuel cell 500, and control means 2000 arranged to control this fuel cell 500 and this cooling circuit 100, on the basis of information from sensors that the control means 2000 comprise, in particular temperature sensors.

[0037] The thermal management system of the vehicle 1000 developed within the framework of the invention is only sized for non-exceptional majority uses, first of all for the cooling of the fuel cell 500: radiator, air inlets or extractions and / or cooling components: electric pumps, motor-fan units GMV, but also for low temperature starting conditions: starting of the fuel cell 500 at ambient temperature below 0°C, temperature increases of the fuel cell 500 and of the electrical energy storage system 600 EESS (from the English “electrical energy storage System”), heating system of the passenger compartment 700 of the vehicle.

[0038] We try to reduce the number, mass and volume of heat exchangers, the surface area of ​​air inlets and extractions, the electrical power to di to supply the various actuators (coolant pump(s), GMV) and heaters.

[0039] A portion of the heat losses of a fuel cell can be used for the passenger compartment heating system 700 and / or the electrical energy storage system 600 and / or the fuel cell 500 itself.

[0040] Thus, the thermal management system of the vehicle is deliberately sized only to cover the majority, and not all, of the cooling needs of the fuel cell 500. For example, a single radiator is implemented when at least one auxiliary radiator would have been required, and the power and range of water pumps, motor-fan unit GMV, heaters, and surfaces of the air inlets or extractions are reduced to a lower level than would otherwise have been required.

[0041] In doing so, by implementing a smaller number of radiators and / or reduced size (as well as the associated conduits) and also reducing the number and / or size of the pump or pumps, the volume of coolant used to cool the fuel cell 500 is reduced (5 to 10 times more expensive than the traditional coolant of internal combustion engines, taking into account the cleanliness and thermal conductivity requirements that a fuel cell 500 requires).

[0042] Contained air intake or extraction surfaces and its contained mass (taking into account the voluntary undersizing of its thermal management system) make it possible not to increase, via the aerodynamic capture drag, the mass and the current requirements, the energy consumption of the vehicle, directly impacting its autonomy and its consumption of dihydrogen.

[0043] A device, for example based on PCM phase change material, for storing and restoring heat is added and implemented, in severe uses for which the vehicle's cooling system is undersized, to store the excess heat emitted that the undersizing of the vehicle's cooling system cannot evacuate. This excess heat will then, for example following the same driving, be released into the cooling circuit of the fuel cell 500, without affecting its operation, to be dissipated to the outside air via the radiator in conditions of use of the vehicle that are less demanding on its thermal system.

[0044] The control means 2000 that the system comprises are arranged to also decide, according to a relevance already known to those skilled in the art, in particular as a function of the ambient temperature, to keep the stored heat within said device for longer in order to restore it, in the thermal management system of the fuel cell 500 and the vehicle 1000, not to be dissipated into the ambient air but to be used in order to allow or improve the starting of the cell. fuel cell 500 at ambient temperatures below 0°C, to contribute to or ensure the temperature increases of the fuel cell 500 and the electrical energy storage system 600, to contribute to or ensure the heating of the passenger compartment 700.

[0045] More particularly, [Fig.2] details the architecture of the cooling circuit 100, which is implemented to ensure the thermal management of the fuel cell 500 and the vehicle 1000. The fuel cell 500 comprises an assembly of cells 1 also called a “stack”, and other components necessary for its operation not shown here. The coolant is moved within the cooling circuit 100 of the assembly of cells 1 by a first pump 20. This first pump 20 is preferably, but not limited to, electrically driven.

[0046] In a first variant illustrated in [Fig.2], the first pump 20 is preferably arranged upstream of the cell assembly 1, so that the latter is then preferably arranged at the discharge of the first pump 20.

[0047] In a second variant, the first pump 20 is arranged downstream of the cell assembly 1, so that the latter is then arranged at the suction of the first pump 20.

[0048] At the suction (inlet) of the first pump 20 is arranged a pressure-static valve 10, for example moved against a return spring by the vacuum exerted by the first pump 20 in operation. The closed position of the valve 10 makes it possible to avoid parasitic circulation of coolant within the cooling circuit 100, in particular within the cell assembly 1. Immediately upstream of the cell assembly 1 is arranged within the cooling circuit 100 a particle filter 11 arranged to protect the constituent parts of the cell assembly 1.

[0049] Preferably, the cooling circuit 100 comprises several branches in parallel. The variant in [Fig.l] thus comprises four branches.

[0050] The first branch 110 comprises the cell assembly 1, the particle filter 11, the first pump 20 and the valve 10.

[0051] A second branch 120 comprises at least one radiator 2 to which is fixed at least one motor-fan unit 2a also called GMV, the assembly ensuring the dissipation to the outside air of the calories by the cooling liquid in the entire cooling circuit 100.

[0052] A third branch 130 comprises at least one heat exchanger 3 of the liquid / liquid type, between the (specific) cooling liquid of the cell assembly 1 and the cooling liquid of at least two other fluid loops of the vehicle 1000, for example one that the heating system 700 comprises for ensuring the heating of the passenger compartment and comprising at least one electric heater and a heat exchanger (not shown) of the liquid / air type between this coolant and the air entering the passenger compartment, and the other ensuring the heating and cooling of the electrical energy storage system 600 EESS of the vehicle by means of a heat exchanger between this coolant and components of the electrical energy storage system 600 EESS of the vehicle (in particular electrochemical cells). To ensure the heat exchange between the coolant of the cell assembly 1 and the coolant of one of the at least two other fluid loops, this at least one heat exchanger 3 comprises for this liquid an inlet 3a and an outlet 3b.

[0053] A fourth branch 140 is a thermal reserve branch which comprises a device for storing and releasing or restoring heat, for example based on phase change material PCM, called thermal reserve 4, as well as a second coolant pump 40, designed so that the direction of circulation of the coolant through the second pump 40 can be reversed by a control request of the second pump 40 coming from a computer or a part of a computer not shown, and which comprises the control means 2000 of the vehicle 1000.

[0054] This reversal of the direction of rotation of the second pump 40 can for example be implemented by controlling, differently from the usual direction, the switching of semiconductors of the transistor, IGBT or MOSFET type of an inverter controlling the rotation of the electric motor of the second pump 40.

[0055] A first three-way valve 50 is arranged at the interface between the fourth branch 140 and the other branches of the cooling circuit 100.

[0056] A second three-way valve 30 is arranged at the interface between the third branch 130 and the other branches of the cooling circuit 100.

[0057] The cooling circuit 100 also comprises a reservoir 13 of cooling liquid for the cell assembly 1, arranged to ensure the functions of degassing the cooling circuit 100, thermal expansion of the liquid and pressurization of the cooling circuit 100 at the inlet of the first pump 20, upstream of the valve 10, so that the closing of the valve 10 prevents the cooling liquid from passing through the reservoir 13.

[0058] The reservoir 13 provides two inlets for the coolant.

[0059] A first inlet 13a opens into the air into the tank 13 (above the maximum liquid level in the tank 13), coming from an auxiliary outlet of coolant from the cell assembly 1 via an auxiliary branch 150 of the cooling circuit 100 carrying an ion exchanger or deionizer 12 in order to preserve a very low electrical conductivity of the coolant. within the cooling circuit 100 and passing through the cell assembly 1.

[0060] A second inlet 13b opens underwater into the tank 13 (below the minimum liquid level in the tank 13, coming from an auxiliary coolant outlet 2b of the radiator 2 arranged within the radiator 2 so that this portion of liquid flow which comes from it has not exchanged calories through the radiator 2 with the outside air moved through the radiator 2 by the movement of the vehicle and / or the activation of the motor-fan unit 2a.

[0061] The reservoir 13 provides an outlet 13c for the coolant to the suction of the first pump 20, previously through the valve 10.

[0062] [Fig.3] is a table which explains the configurations taken by the first valve 50, the second valve 30, the second pump 40, the first pump 20, and the valve 10, for different operating modes of the cooling circuit 100. These different operating modes are referenced by letters, from A to L.

[0063] In a first operating mode A of [Fig. 3], the cell assembly 1 has a significant cooling requirement that the cooling circuit 100 deliberately cannot completely dissipate to the outside air via the radiator 2 and the activation of the motor-fan unit 2a: it is then necessary to store the excess calories within the thermal reserve 4. In this operating mode, the first pump 20 is active, the valve 10 is open, and the first pump 20 propels the coolant through the cell assembly 1 to ensure its cooling. The first valve 50 adopts a position allowing the hot coolant from the cell assembly 1 to be distributed in predetermined proportions between the radiator 2 and the thermal reserve 4 within which the circulation of coolant is encouraged by the activation of the second pump 40.The second valve 30 adopts a position allowing the portions of coolant, cooled through the radiator 2 by having transferred calories to the outside air and through the thermal reserve 4 by having transferred and stored calories to the phase change material PCM which has then changed thermodynamic state, to reach the inlet of the first pump 20 through the open valve 10. Depending on conditions external to the operation of the cell assembly 1, it may or may not be necessary for a third portion of the hot coolant from the cell assembly 1 to pass through the heat exchanger 3.

[0064] If this crossing of the heat exchanger 3 is necessary, it may be for example by an external ambient such that it is relevant to ensure by this means the heating of the passenger compartment (for example by an ambient temperature lower than 15°C) and / or to ensure the heating of the electrical energy storage system 600 EESS of the vehicle.

[0065] If this crossing of the heat exchanger 3 is not necessary, the second valve 30 closes the third branch 130.

[0066] In this cooling mode, a very small portion of coolant from the cell assembly 1 and the radiator 2 passes through the reservoir 13 to be readmitted to the inlet of the cell assembly 1 by the action of the first pump 20 through the valve 10.

[0067] Thus, in this first operating mode A, a portion of the calories dissipated by the cell assembly 1 in its cooling liquid is stored in the thermal reserve 4, while another portion is dissipated to the outside air via the radiator 2 assisted or not by the motor-fan unit 2a.

[0068] The thermal reserve 4 is sized as a function of the thermal power dissipated by the assembly of cells 1 in its cooling liquid and the thermal power dissipated to the ambient air by the radiator 2 assisted by the motor-fan unit 2a: the difference between these two thermal powers dictates the size of the thermal reserve 4.

[0069] Using a PCM phase change material makes it possible to maintain the temperature of the coolant at the inlet of the cell assembly 1 constant regardless of the thermal power dissipated by the cell assembly 1 and the power supplied to the vehicle's electrical network.

[0070] Thus, when the thermal power dissipated by the cell assembly 1 in its coolant is greater than the thermal power dissipated by the radiator 2 assisted by the motor-fan unit 2a (which depends on the dimensions of the radiator, the flow rates of coolant and air passing through it, the positioning and sizes of the air inlets and extractions, and other conventional parameters), then the excess heat extracted from the coolant is stored in the thermal reserve 4.

[0071] Conversely, when the thermal power dissipated by the cell assembly 1 is lower than the dissipable thermal power, a reduction in the temperature of the coolant then generated by passing through the radiator 2 allows the thermal reserve 4 to release the heat and thus maintain a constant temperature of the coolant at the inlet of the cell assembly 1.

[0072] The energy to be stored in the thermal reserve 4 is the product of the flow rate of coolant through the cell assembly 1 by the specific heat capacity of the coolant, by the temperature difference across the radiator 2 and by the time step of the real-time evaluation by the algorithm (for example every second) at the level of the control means. The mass of phase change material PCM to be implemented in the thermal reserve 4 is deduced therefrom, from the cumulative energy to be stored, by dividing it by the latent heat of phase change of the material envisaged for the temperature range considered.

[0073] A first approach consists of dimensioning this mass of phase change material PCM and the associated thermal regulation so that the residual thermal energy stored in the thermal reserve 4 at the start and end of the runs is identical. A second approach consists of retaining excess stored heat to restore it to the vehicle (cabin heating system 700, stack 1, electrical energy storage system 600) during the next cold start, in cold outside conditions.

[0074] In the second operating mode B of [Fig. 3], we find ourselves in the case which has just been described such that the cooling requirement of the cell assembly 1 is lower than the thermal power dissipated through the radiator 2. If it is then not relevant to keep in the thermal reserve 4 the quantity of excess heat previously stored, then this is destored from the thermal reserve 4. To this end, the first pump 20, which is active taking into account the need to circulate the coolant through the cell assembly 1, and the second valve 30 adopt the same configurations as in the first operating mode A, depending on whether or not it is necessary for a portion of the hot coolant from the cell assembly 1 to pass through the heat exchanger 3. The direction of rotation of the second pump 40 is reversed, as visible in the table of [Fig.3], so that a portion of cold coolant from the radiator 2 is taken by the second pump 40 downstream of the radiator 2 and upstream of the second valve 30 and passes through the thermal reserve 4 from where the heat is released.

[0075] The configuration taken by the first valve 50 allows the hot coolant, removed from the thermal reserve 4, to join the coolant coming from the assembly of cells 1, the assembly passing through the radiator 2 to transfer to the outside air, with or without the assistance of the motor-fan unit 2a, the calories dissipated in the coolant at the inlet of the radiator 2 by the assembly of cells 1 and by the thermal reserve 4.

[0076] It is possible for a 1000 fuel cell electric motor vehicle 500 FCEV to operate and move solely from the electrical energy discharged from the vehicle's electrical energy storage system 600 EESS and in this case, the proton exchange membrane fuel cell 500 is deactivated. In this case, the cell assembly 1 and the first pump 20 are inactive: the valve 10 is then closed, in the rest position. It is then possible to release the heat stored in the thermal reserve 4 to dissipate it, according to the different life situations, through the different branches of the cooling circuit 100.

[0077] If it is then relevant to dissipate the heat previously stored by the thermal reserve 4 through the heat exchanger 3 only, the cooling circuit- dissement 100 then adopts the third operating mode C of [Fig.2].

[0078] In this third operating mode C of [Fig.3] the second pump 40 sucks in the cooling liquid heated by the calories discharged from the thermal reserve 4, and delivers it, taking into account the configuration taken by the second valve 30, through the heat exchanger 3, the access of this liquid to the stack 1 being blocked by the second valve 30.

[0079] By activating a fluid loop (not shown in the figures) connected to the inlet 3a and the outlet 3b of the heat exchanger 3, for example and not limited to activating a water pump arranged on this fluid loop, the heat exchanger 3 dissipates in the coolant which passes through it via the inlet 3a and outlet 3b the calories transferred by the thermal reserve 4 to the coolant of the cooling circuit 100. This fluid loop (not shown) connected to the inlet 3a and outlet 3b may correspond to a branch of the passenger compartment heating circuit, or to a branch of the thermal management circuit of the vehicle's 600 EESS electrical energy storage system, activated here in order to heat the latter.At the end of the heat exchanger 3, the coolant from the cooling circuit 100 reaches, via the position taken by the first valve 50, which blocks access to the radiator 2, the inlet of the thermal reserve 4.

[0080] In this third operating mode C of [Fig. 3], no circulation of coolant is possible through the cell assembly 1, due to the position taken by the second valve 30 and because the valve 10 is closed. And no circulation of coolant is possible through the radiator 2, for example in the opposite direction in the radiator 2 via the activation of the second pump 40, due to the position taken by the first valve 50 and because the valve 10 is closed.

[0081] This third operating mode C of [Fig. 3] can also be activated, while the vehicle 1000 is not in use, in order to ensure or contribute to the heating of the passenger compartment 700 or to the heating of the electrical energy storage system 600 EESS of the vehicle by the previously stored calories discharged from the thermal reserve 4, regardless of the duration of non-use of the vehicle (taking into account the choice and the mass of phase change material PCM on board, as well as the external ambient conditions and any thermal insulation solutions implemented).

[0082] If it is then relevant to dissipate the heat previously stored by the thermal reserve 4 outside the vehicle through the radiator 2, the cooling circuit 100 then adopts the fourth operating mode D of [Fig. 3], or the operating mode E of [Fig. 3] (the operating mode E being an alternative to the fourth operating mode D, only varying the direction of circulation of the coolant in the fourth branch 140 and in the second branch 120 of the cooling circuit 100 put into communication), while the vehicle 1000 is in or out of use.

[0083] According to the fourth operating mode D of [Fig. 3], the cold coolant from the radiator 2 is taken by the second pump 40 which discharges it through the thermal reserve 4 from where the heat is then released. The configuration taken by the first valve 50 only allows the passage of the hot coolant, released from the thermal reserve 4, through the radiator 2 to transfer, with the assistance of the motor-fan unit 2a, to the outside air the calories discharged into the coolant by the thermal reserve 4. The position taken by the second valve 30 prevents the coolant from passing through it, in the direction of the first branch 110 or third branch 130 of the cooling circuit 100.

[0084] In this fourth operating mode D of [Fig.3], no circulation of coolant is possible through the reservoir 13 and the cell assembly 1 coming from the radiator 2, by the configurations adopted by the first valve 50 and the second valve 30, and because the valve 10 is closed.

[0085] If it is then relevant to dissipate the heat previously stored by the thermal reserve 4 through the assembly of cells 1 only, the cooling circuit 100 then adopts the fifth operating mode F of [Fig. 3]: the second pump 40 sucks in the cooling liquid heated by the calories discharged from the thermal reserve 4 and delivers it, taking into account the configuration taken by the second valve 30, to the inlet of the first pump 20, the access of this liquid to the heat exchanger 3 being blocked by the second valve 30.

[0086] In this fifth operating mode F, the first pump 20 is activated at a low flow rate setpoint, in order to assist the second pump 40. The valve 10 then open allows the coolant discharged at its outlet by the first pump 20 to pass through the cell assembly 1 at the inlet of the first valve 50. The coolant from the cell assembly 1 cannot pass through the heat exchanger 3, the third 130 branch of the cooling circuit 100 being blocked by the second valve 30. The first valve 50 directs the coolant, cooled at the passage through the cell assembly 1, through the thermal reserve 4 where it is charged with calories then released by the latter.

[0087] This fifth operating mode F can also be activated, while the vehicle 1000 is not in use, in order to ensure or contribute to the heating of the cell assembly 1 to prepare or during cold starting, in negative ambient temperature, thanks to the previously stored calories discharged from the thermal reserve 4, whatever the duration of the non-use of the vehicle (taking into account the choice and the mass of PCM on board, as well as the conditions

[0088] However, this fifth operating mode F, such that a circulation of coolant is activated within the deactivated cell assembly 1, is subject to some restrictions of use: monitoring of the temperatures of the liquid at the inlet and outlet of the pack (these two pieces of information and their difference), of the humidity (calculated) of the internal membrane of the cells of the fuel cell 500, of the relative humidity (calculated or measured) at the cathode of each cell, this in order to avoid any risk of drying out or flooding of the membrane and therefore any risk of reversible or irreversible damage or degradation of the fuel cell 500.In particular, the heating capacity of the cell assembly 1 by this fifth operating mode F may be limited by the activation under a pre-fixed and non-maximum command of the second pump 40 and the first pump 20, and / or where appropriate by adopting the sixth operating mode G presented below.

[0089] The sixth operating mode G of [Fig. 3] is adopted, either from any prior state of the cooling circuit 100 and the vehicle 1000, if it is relevant to dissipate the heat previously stored by the thermal reserve 4 through both the cell assembly 1 and the heat exchanger 3, or while the cooling circuit 100 occupied the fifth operating mode F. Compared to this fifth operating mode F, the sixth operating mode G additionally authorizes the circulation of liquid in the third branch 130, through the heat exchanger 3: this third branch 130 then acts in the cooling circuit 100 as a bypass of the cell assembly 1 and a source of additional dissipation of the calories released by the thermal reserve 4.

[0090] This sixth operating mode G can also be activated, while the vehicle 1000 is not in use, in order to ensure or contribute, as in the fifth operating mode F and with the same reserves, to the heating of the cell assembly 1 and at the same time to the heating of the passenger compartment 700 or to the heating of the electrical energy storage system 600 EESS of the vehicle by the previously stored calories discharged from the thermal reserve 4, regardless of the duration of the non-use of the vehicle 1000.

[0091] The seventh operating mode H of [Fig. 3] makes it possible to release, through the radiator 2 and the heat exchanger 3, the calories stored in the thermal storer 4, while avoiding any circulation of coolant through the cell assembly 1 which is then deactivated. In this seventh operating mode H, the first pump 20 is inactive, the valve 10 is at rest, closed, and the second pump 40 is activated so as to discharge through the thermal reserve 4 the coolant coming from both the radiator 2 and the heat exchanger 3, thanks to the configuration taken by the first valve 50 which directs the liquid into the second branch 120 and into the third branch 130 dissipated in parallel, the second valve 30 and the flap 10 preventing any circulation of liquid through the assembly of cells 1.

[0092] The eighth operating mode I of [Fig. 3] ensures the cooling of the cell assembly 1, then under low load, solely by the radiator 2: the thermal reserve 4 is here unused. In this eighth operating mode I, the valve 10 is open, the first pump 20 is active and delivers the coolant from the cooling circuit 100 through the cell assembly 1. The first valve 50 disconnects the fourth 140 branch of the cooling circuit 100: any circulation through the thermal reserve 4 is inhibited and the second pump 40 is deactivated. The first valve 50 thus directs the liquid from the cell assembly 1 through the radiator 2.

[0093] Depending on the position of the second valve 30, the coolant from the cell assembly 1 also passes through the third branch 130 and the heat exchanger 3, arranged in parallel with the second branch 120 and the radiator 2. The first pump 20 then draws in the liquid from the second valve 30, coming from the radiator 2 alone or at the same time from the heat exchanger 3, and delivers it, through the open valve 10, into the cell assembly 1. In this eighth operating mode I, as in the first operating mode A, a very small portion of coolant from the cell assembly 1 and the radiator 2 passes through the reservoir 13 to be readmitted to the inlet of the cell assembly 1 by the action of the first pump 20 through the valve 10.

[0094] In the ninth operating mode J of [Fig. 3], the third branch 130 is deactivated (all circulation of coolant through the heat exchanger 3 is inhibited) and the cooling of the cell assembly 1 is ensured through the radiator 2 alone or assisted by the thermal reserve 4 depending on the intensity of the load on the fuel cell 500. The deactivation of the third branch 130 then makes it possible to direct all the flow of liquid from the cell assembly 1 through the second branch 120, alone or assisted by the fourth branch 140 arranged in parallel.

[0095] In this ninth operating mode J, the valve 10 is open, the first pump 20 is active and delivers the coolant from the cooling circuit 100 through the cell assembly 1. The position of the second valve 30 inhibits any circulation of coolant through the heat exchanger 3 and the liquid from the cell assembly 1 is directed through the radiator 2 alone or at the same time through the thermal reserve 4; the second pump 40 is preferably deactivated, or activated if it is necessary to assist by this bias the flow of liquid through the reserve 4. As in the first operating mode A and as in the eighth operating mode I, a very small portion of liquid from the cell assembly 1 and the radiator 2 passes through the reservoir 13 to be readmitted to the inlet of the cell assembly 1 by the action of the first pump 20 through the valve 10.

[0096] The tenth operating mode K of [Fig. 3] makes it possible to heat the cell assembly 1 by activating, within the fluid loop (not shown) connected to the inlet 3a and the outlet 3b of the heat exchanger 3, a heater arranged on this fluid loop to heat the passenger compartment 700 and / or the electrical energy storage system 600 EESS of the vehicle, for example while the vehicle 1000 is connected to an external energy source. Under these conditions, the heat exchanger 3 dissipates to the coolant of the cooling circuit 100 the calories supplied by the coolant which passes through it via the inlet 3a and the outlet 3b.

[0097] In this tenth operating mode K, the first valve 50 inhibits any circulation of coolant through the second branch 120 and fourth branch 140 of the cooling circuit 100 and the second pump 40 is deactivated. The activated first pump 20 ensures the circulation of coolant in the cooling circuit 100 within the cell assembly 1 and the valve 10 is open. The configuration then taken by the second valve 30 connects the first branch 110 and the third branch 130 so that the hot liquid from the heat exchanger 3 passes through the cell assembly 1. A very small portion of liquid from the cell assembly 1 passes through the reservoir 13 to be readmitted to the inlet of the cell assembly 1 by the action of the first pump 20 through the valve 10.This tenth operating mode K can also be implemented while the cell assembly 1 is active under low load and in the temperature rise phase and a low liquid flow rate is possible through the cell assembly 1.

[0098] In an eleventh operating mode L of [Fig. 3], the cell assembly 1 is active under significant stress, requiring a significant flow of liquid through the cell assembly 1, and in the temperature rise phase: the first valve 50 inhibits any circulation of coolant through the second branch 120 of the cooling circuit 100 and the radiator 2. The fourth branch 140 acts as a by-pass or diversion in order to ensure the passage of all the required flow through the cell assembly 1 which, in the tenth operating mode K, the third branch 130 alone could not have supported without risking damaging the heat exchanger 3 by internal erosion or by excessively high pressure at its inlet or in the cooling circuit 100.

[0099] The second pump 40 may or may not be activated depending on the internal flow rate requirements of stack 1 and / or to overcome the pressure drop of the thermal reserve 4. The second valve 30 allows the return of the liquid from the fourth branch 140 to the inlet of the first active water pump 20, the valve 10 then being open, and may also, depending on the need or not to simultaneously ensure the heating of the passenger compartment 700 and / or the EESS 600 of the vehicle 1000, allow the liquid from the cooling circuit 100 to pass through the heat exchanger 3.

[0100] In brief, a summary of each mode of operation of the cooling circuit is provided below.

[0101] The first operating mode A concerns the cooling of the cell assembly 1 of the fuel cell, and the storage of heat in the thermal reserve 4.

[0102] The second operating mode B concerns the cooling of the cell assembly 1, and, at the same time, the destocking of the thermal reserve 4.

[0103] The third operating mode C concerns the destocking of the thermal reserve 4 in the heat exchanger 3, stack 1 deactivated.

[0104] The fourth operating mode D and its derivative mode E concern the destocking of the thermal reserve 4 in the radiator 2, stack 1 deactivated.

[0105] The fifth operating mode F concerns the destocking of the thermal reserve 4 in the activated or deactivated cell assembly 1.

[0106] The sixth operating mode G concerns the destocking of the thermal reserve 4 in the heat exchanger 3 and in the activated or deactivated cell assembly 1.

[0107] The seventh operating mode H concerns the deactivated cell assembly 1: heat storage by the radiator 2 and the heat exchanger 3.

[0108] The eighth operating mode I concerns the cooling only of the cell assembly 1 by the radiator 2.

[0109] The ninth operating mode J concerns the cooling of the cell assembly 1 and the deactivation of the heat exchanger 3.

[0110] The tenth operating mode K concerns the heating of the cell assembly 1 by the heat exchanger 3.

[0111] The eleventh operating mode L concerns the temperature rise of the active cell assembly 1.

[0112] The invention thus provides a significant cooling capacity for a fuel cell and / or heating of the passenger compartment and / or the electrical energy storage system of the vehicle without increasing the mass, dimensions and electrical consumption of the cooling and / or heating components or the aerodynamic drag of the vehicle (range and fuel consumption issues). hydrogen).

[0113] Compared to the prior art cited above, the invention differs by the implementation of a liquid / liquid exchanger on the cooling circuit of the stack, and a pooling of the thermal management functions associated with the different components of the cooling circuit, and in that the invention minimizes the presence of components or exchangers within the cooling circuit of the stack to reduce as much as possible the volume of the circuit (and therefore of cooling liquid implemented in this circuit, which also represents a high cost), and minimizes the exposure of the cooling circuit of the stack to potential contributors to the degradation of the electrical conductivity of the circuit.

[0114] The recovery of the heat dissipated by the stack is carried out in order to optimize the sizing of its cooling circuit, by calculating this sizing on the operating points of greatest occurrence, by voluntarily omitting the exceptional operating points, and thereby by avoiding unnecessarily oversizing the cooling circuit and its constituents.

[0115] The installation, according to the invention, of a first valve and a second valve, of a first pump and a second pump, allows all the circulations adapted to the best cooling of the stack, in particular the reversal of direction of certain flows of the coolant, with the least energy consumption and therefore at low operating costs. The cooling circuit is dimensioned as precisely as possible, precisely because its constitution allows exceptional operating situations to be managed without having to unnecessarily oversize the installation.

[0116] These components, valves and pumps, are simple and easy to maintain. The invention makes it possible to do away with the need for a heater that consumes a lot of energy.

[0117] The invention is well suited to the thermal regulation of an electrochemical energy store, in particular a high voltage traction battery.

[0118] In short, the invention allows a significant reduction in the cost of thermal adaptation (cooling components, liquid), while avoiding any deterioration in the expected performance and performance of the vehicle: longitudinal performance (accelerations, hill take-offs, and the like), and loading capacity (total authorized laden mass MTAC, total authorized rolling mass MTRA) of the vehicle. The equipment of the cooling circuit allows a dimensioning calculated for usual thermal conditions, because the different possible operating modes of this cooling circuit allow the temporary handling of exceptional thermal conditions, without having to unnecessarily oversize the installation, and, therefore, without having to burden the mass of the vehicle, its energy consumption, and its cost price.

[0119] The invention further provides better dynamic performance and thermal comfort of the vehicle in negative ambient temperatures.

Claims

Claims

1. Electric or hybrid motor vehicle (1000), comprising a fuel cell (500) comprising a cell assembly (1), and a cooling circuit (100) arranged for cooling said cell assembly (1), and control means (2000) arranged to control said fuel cell (500) and said cooling circuit (100) on the basis of information from sensors included in said control means (2000), characterized in that said cooling circuit (100) comprises, in a first branch (110) comprising said cell assembly (1), a first pump (20) upstream of said cell assembly (1), arranged to move a coolant through said cell assembly (1), said first branch (110) opening, downstream of said cell assembly (1),on a first valve (50) controlled by said control means (2000) and arranged to authorize or prohibit the circulation of said coolant between said first branch (110), a second branch (120) comprising at least one radiator (2) cooperating with at least one motor-fan unit (2a), and a thermal reserve branch (140) which comprises a thermal reserve (4) capable of storing, releasing, or restoring heat, upstream of a second pump (40) whose direction of circulation is controlled by said control means (2000), said cooling circuit (100) comprising, downstream of said at least one radiator (2) and said second pump (40), a second valve (30) controlled by said control means (2000), upstream of said first pump (20).,

2. Electric or hybrid motor vehicle (1000), according to claim 1 characterized in that said cooling circuit (100) comprises a third branch (130) whose inlet is arranged downstream of said cell assembly (1) and upstream of said first valve (50), and whose outlet joins said second valve (30), said third branch (130) comprising at least one heat exchanger (3) of liquid / liquid type, between said coolant of said cooling circuit (100) and another coolant of at least two other fluid loops of said vehicle (1000).

3. Electric or hybrid motor vehicle (1000), according to claim 2 characterized in that said vehicle (1000) comprises an electrical energy storage system (600), and a device arranged to ensure the heating and cooling of said electrical energy storage system (600) and which constitutes one of said fluidic loops.

4. Electric or hybrid motor vehicle (1000), according to claim 2 characterized in that said vehicle (1000) comprises a heating system (700) arranged to ensure the heating of the passenger compartment of said vehicle (1000) and which constitutes one of said fluid loops.

5. Electric or hybrid motor vehicle (1000) according to any one of claims 1 to 4 characterized in that said cooling circuit (100) comprises a pressure-controlled valve (10), in said first branch (110) at the inlet of which first pump (20), opposite said assembly of cells (1).

6. Electric or hybrid motor vehicle (1000) according to any one of claims 1 to 5, characterized in that said cooling circuit (100) comprises a reservoir (13) of coolant, arranged to ensure the functions of degassing said cooling circuit (100), thermal expansion of the liquid and pressurization of the cooling circuit (100) at the inlet of said first pump (20).

7. Electric or hybrid motor vehicle (1000) according to claims 5 and 6 characterized in that said reservoir (13) is upstream of said valve (10), so that closing of said valve (10) prevents said coolant from passing through said reservoir (13).

8. Electric or hybrid motor vehicle (1000) according to any one of claims 6 to 7 characterized in that said reservoir (13) provides said coolant with a first inlet (13a) which opens into said reservoir (13) in the air from an auxiliary coolant outlet of said cell assembly (1) via an auxiliary branch (150) which comprises said cooling circuit (100) and which comprises a deionizer (12) arranged to preserve a very low electrical conductivity of said coolant within said cooling circuit (100), and a second inlet (13b) opening underwater into said reservoir (13),from an auxiliary coolant outlet (2b) included in said radiator (2) and which is arranged within said radiator (2) so that this portion of liquid flow which comes from it has not exchanged calories through the radiator (2) with the air, externally moved through said radiator (2) by the advancement of said vehicle (1000) and / or the activation of said motor-fan unit (2a), said reservoir (13) being arranged to provide an outlet (13c) for said coolant towards the suction of said first pump (20), previously through said valve (10).

9. Electric or hybrid motor vehicle (1000) according to any one of claims 1 to 8 characterized in that said thermal reserve (4) comprises a device for storing and releasing or restoring heat based on PCM phase change material.

10. Electric or hybrid motor vehicle (1000) according to any one of claims 1 to 9, characterized in that said cooling circuit (100) comprises, on said first branch (110), immediately upstream of said cell assembly (1), a particle filter (11) arranged to protect the constituent parts of said cell assembly (1).

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