WO2023052249A1 - System for supplying hydrogen to a fuel cell - Google Patents

System for supplying hydrogen to a fuel cell Download PDF

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Publication number
WO2023052249A1
WO2023052249A1 PCT/EP2022/076449 EP2022076449W WO2023052249A1 WO 2023052249 A1 WO2023052249 A1 WO 2023052249A1 EP 2022076449 W EP2022076449 W EP 2022076449W WO 2023052249 A1 WO2023052249 A1 WO 2023052249A1
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WO
WIPO (PCT)
Prior art keywords
hydrogen
heat transfer
transfer fluid
fuel cell
evaporator
Prior art date
Application number
PCT/EP2022/076449
Other languages
French (fr)
Inventor
David Gerard
Robert Yu
Original Assignee
Renault S.A.S.
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Renault S.A.S. filed Critical Renault S.A.S.
Priority to CN202280059815.XA priority Critical patent/CN117999680A/en
Publication of WO2023052249A1 publication Critical patent/WO2023052249A1/en

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Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M8/00—Fuel cells; Manufacture thereof
    • H01M8/04—Auxiliary arrangements, e.g. for control of pressure or for circulation of fluids
    • H01M8/04082—Arrangements for control of reactant parameters, e.g. pressure or concentration
    • H01M8/04089—Arrangements for control of reactant parameters, e.g. pressure or concentration of gaseous reactants
    • H01M8/04111—Arrangements for control of reactant parameters, e.g. pressure or concentration of gaseous reactants using a compressor turbine assembly
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F17—STORING OR DISTRIBUTING GASES OR LIQUIDS
    • F17C—VESSELS FOR CONTAINING OR STORING COMPRESSED, LIQUEFIED OR SOLIDIFIED GASES; FIXED-CAPACITY GAS-HOLDERS; FILLING VESSELS WITH, OR DISCHARGING FROM VESSELS, COMPRESSED, LIQUEFIED, OR SOLIDIFIED GASES
    • F17C13/00—Details of vessels or of the filling or discharging of vessels
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M8/00—Fuel cells; Manufacture thereof
    • H01M8/04—Auxiliary arrangements, e.g. for control of pressure or for circulation of fluids
    • H01M8/04007—Auxiliary arrangements, e.g. for control of pressure or for circulation of fluids related to heat exchange
    • H01M8/04029—Heat exchange using liquids
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M8/00—Fuel cells; Manufacture thereof
    • H01M8/04—Auxiliary arrangements, e.g. for control of pressure or for circulation of fluids
    • H01M8/04007—Auxiliary arrangements, e.g. for control of pressure or for circulation of fluids related to heat exchange
    • H01M8/04067—Heat exchange or temperature measuring elements, thermal insulation, e.g. heat pipes, heat pumps, fins
    • H01M8/04074—Heat exchange unit structures specially adapted for fuel cell
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M8/00—Fuel cells; Manufacture thereof
    • H01M8/04—Auxiliary arrangements, e.g. for control of pressure or for circulation of fluids
    • H01M8/04082—Arrangements for control of reactant parameters, e.g. pressure or concentration
    • H01M8/04201—Reactant storage and supply, e.g. means for feeding, pipes
    • H01M8/04208—Cartridges, cryogenic media or cryogenic reservoirs
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M8/00—Fuel cells; Manufacture thereof
    • H01M8/04—Auxiliary arrangements, e.g. for control of pressure or for circulation of fluids
    • H01M8/04298—Processes for controlling fuel cells or fuel cell systems
    • H01M8/04694—Processes for controlling fuel cells or fuel cell systems characterised by variables to be controlled
    • H01M8/04746—Pressure; Flow
    • H01M8/04753—Pressure; Flow of fuel cell reactants
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M8/00—Fuel cells; Manufacture thereof
    • H01M8/04—Auxiliary arrangements, e.g. for control of pressure or for circulation of fluids
    • H01M8/04298—Processes for controlling fuel cells or fuel cell systems
    • H01M8/04694—Processes for controlling fuel cells or fuel cell systems characterised by variables to be controlled
    • H01M8/04746—Pressure; Flow
    • H01M8/04768—Pressure; Flow of the coolant
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F17—STORING OR DISTRIBUTING GASES OR LIQUIDS
    • F17C—VESSELS FOR CONTAINING OR STORING COMPRESSED, LIQUEFIED OR SOLIDIFIED GASES; FIXED-CAPACITY GAS-HOLDERS; FILLING VESSELS WITH, OR DISCHARGING FROM VESSELS, COMPRESSED, LIQUEFIED, OR SOLIDIFIED GASES
    • F17C2221/00—Handled fluid, in particular type of fluid
    • F17C2221/01—Pure fluids
    • F17C2221/012—Hydrogen
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F17—STORING OR DISTRIBUTING GASES OR LIQUIDS
    • F17C—VESSELS FOR CONTAINING OR STORING COMPRESSED, LIQUEFIED OR SOLIDIFIED GASES; FIXED-CAPACITY GAS-HOLDERS; FILLING VESSELS WITH, OR DISCHARGING FROM VESSELS, COMPRESSED, LIQUEFIED, OR SOLIDIFIED GASES
    • F17C2223/00—Handled fluid before transfer, i.e. state of fluid when stored in the vessel or before transfer from the vessel
    • F17C2223/01—Handled fluid before transfer, i.e. state of fluid when stored in the vessel or before transfer from the vessel characterised by the phase
    • F17C2223/0146—Two-phase
    • F17C2223/0153—Liquefied gas, e.g. LPG, GPL
    • F17C2223/0161—Liquefied gas, e.g. LPG, GPL cryogenic, e.g. LNG, GNL, PLNG
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F17—STORING OR DISTRIBUTING GASES OR LIQUIDS
    • F17C—VESSELS FOR CONTAINING OR STORING COMPRESSED, LIQUEFIED OR SOLIDIFIED GASES; FIXED-CAPACITY GAS-HOLDERS; FILLING VESSELS WITH, OR DISCHARGING FROM VESSELS, COMPRESSED, LIQUEFIED, OR SOLIDIFIED GASES
    • F17C2223/00—Handled fluid before transfer, i.e. state of fluid when stored in the vessel or before transfer from the vessel
    • F17C2223/03—Handled fluid before transfer, i.e. state of fluid when stored in the vessel or before transfer from the vessel characterised by the pressure level
    • F17C2223/033—Small pressure, e.g. for liquefied gas
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F17—STORING OR DISTRIBUTING GASES OR LIQUIDS
    • F17C—VESSELS FOR CONTAINING OR STORING COMPRESSED, LIQUEFIED OR SOLIDIFIED GASES; FIXED-CAPACITY GAS-HOLDERS; FILLING VESSELS WITH, OR DISCHARGING FROM VESSELS, COMPRESSED, LIQUEFIED, OR SOLIDIFIED GASES
    • F17C2225/00—Handled fluid after transfer, i.e. state of fluid after transfer from the vessel
    • F17C2225/01—Handled fluid after transfer, i.e. state of fluid after transfer from the vessel characterised by the phase
    • F17C2225/0107—Single phase
    • F17C2225/0123—Single phase gaseous, e.g. CNG, GNC
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F17—STORING OR DISTRIBUTING GASES OR LIQUIDS
    • F17C—VESSELS FOR CONTAINING OR STORING COMPRESSED, LIQUEFIED OR SOLIDIFIED GASES; FIXED-CAPACITY GAS-HOLDERS; FILLING VESSELS WITH, OR DISCHARGING FROM VESSELS, COMPRESSED, LIQUEFIED, OR SOLIDIFIED GASES
    • F17C2225/00—Handled fluid after transfer, i.e. state of fluid after transfer from the vessel
    • F17C2225/03—Handled fluid after transfer, i.e. state of fluid after transfer from the vessel characterised by the pressure level
    • F17C2225/036—Very high pressure, i.e. above 80 bars
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F17—STORING OR DISTRIBUTING GASES OR LIQUIDS
    • F17C—VESSELS FOR CONTAINING OR STORING COMPRESSED, LIQUEFIED OR SOLIDIFIED GASES; FIXED-CAPACITY GAS-HOLDERS; FILLING VESSELS WITH, OR DISCHARGING FROM VESSELS, COMPRESSED, LIQUEFIED, OR SOLIDIFIED GASES
    • F17C2227/00—Transfer of fluids, i.e. method or means for transferring the fluid; Heat exchange with the fluid
    • F17C2227/03—Heat exchange with the fluid
    • F17C2227/0302—Heat exchange with the fluid by heating
    • F17C2227/0304—Heat exchange with the fluid by heating using an electric heater
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F17—STORING OR DISTRIBUTING GASES OR LIQUIDS
    • F17C—VESSELS FOR CONTAINING OR STORING COMPRESSED, LIQUEFIED OR SOLIDIFIED GASES; FIXED-CAPACITY GAS-HOLDERS; FILLING VESSELS WITH, OR DISCHARGING FROM VESSELS, COMPRESSED, LIQUEFIED, OR SOLIDIFIED GASES
    • F17C2227/00—Transfer of fluids, i.e. method or means for transferring the fluid; Heat exchange with the fluid
    • F17C2227/03—Heat exchange with the fluid
    • F17C2227/0302—Heat exchange with the fluid by heating
    • F17C2227/0309—Heat exchange with the fluid by heating using another fluid
    • F17C2227/0323—Heat exchange with the fluid by heating using another fluid in a closed loop
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F17—STORING OR DISTRIBUTING GASES OR LIQUIDS
    • F17C—VESSELS FOR CONTAINING OR STORING COMPRESSED, LIQUEFIED OR SOLIDIFIED GASES; FIXED-CAPACITY GAS-HOLDERS; FILLING VESSELS WITH, OR DISCHARGING FROM VESSELS, COMPRESSED, LIQUEFIED, OR SOLIDIFIED GASES
    • F17C2227/00—Transfer of fluids, i.e. method or means for transferring the fluid; Heat exchange with the fluid
    • F17C2227/03—Heat exchange with the fluid
    • F17C2227/0367—Localisation of heat exchange
    • F17C2227/0388—Localisation of heat exchange separate
    • F17C2227/0393—Localisation of heat exchange separate using a vaporiser
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F17—STORING OR DISTRIBUTING GASES OR LIQUIDS
    • F17C—VESSELS FOR CONTAINING OR STORING COMPRESSED, LIQUEFIED OR SOLIDIFIED GASES; FIXED-CAPACITY GAS-HOLDERS; FILLING VESSELS WITH, OR DISCHARGING FROM VESSELS, COMPRESSED, LIQUEFIED, OR SOLIDIFIED GASES
    • F17C2265/00—Effects achieved by gas storage or gas handling
    • F17C2265/06—Fluid distribution
    • F17C2265/066—Fluid distribution for feeding engines for propulsion
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F17—STORING OR DISTRIBUTING GASES OR LIQUIDS
    • F17C—VESSELS FOR CONTAINING OR STORING COMPRESSED, LIQUEFIED OR SOLIDIFIED GASES; FIXED-CAPACITY GAS-HOLDERS; FILLING VESSELS WITH, OR DISCHARGING FROM VESSELS, COMPRESSED, LIQUEFIED, OR SOLIDIFIED GASES
    • F17C2270/00—Applications
    • F17C2270/01—Applications for fluid transport or storage
    • F17C2270/0165—Applications for fluid transport or storage on the road
    • F17C2270/0168—Applications for fluid transport or storage on the road by vehicles
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F17—STORING OR DISTRIBUTING GASES OR LIQUIDS
    • F17C—VESSELS FOR CONTAINING OR STORING COMPRESSED, LIQUEFIED OR SOLIDIFIED GASES; FIXED-CAPACITY GAS-HOLDERS; FILLING VESSELS WITH, OR DISCHARGING FROM VESSELS, COMPRESSED, LIQUEFIED, OR SOLIDIFIED GASES
    • F17C2270/00—Applications
    • F17C2270/01—Applications for fluid transport or storage
    • F17C2270/0165—Applications for fluid transport or storage on the road
    • F17C2270/0184—Fuel cells
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M2250/00—Fuel cells for particular applications; Specific features of fuel cell system
    • H01M2250/20—Fuel cells in motive systems, e.g. vehicle, ship, plane

Definitions

  • the present invention relates to the field of electric vehicles, and more particularly to the energy supply systems of these electric vehicles.
  • the term “electric vehicles” means both purely electric vehicles, for which the only power source is a source of electrical energy, and hybrid vehicles, which combine this source of electrical energy with a thermal energy source. To date, these electric vehicles have, compared to conventional thermal vehicles, a reduced autonomy which can be detrimental to users of electric vehicles, in particular when they wish to make long journeys.
  • Range can be improved by increasing the capacity or quantity of the batteries that power the vehicles, but such increases come at a high cost and can also cause congestion issues.
  • Another solution to increase the autonomy is to supply the battery, in addition to an external energy source, with an energy source internal to the vehicle, such as for example a fuel cell which can then be used as an extender. autonomy.
  • the fuel cell is electrically connected in parallel with the battery.
  • the electric motor is powered first by the battery and, if necessary, by the fuel cell when the charge of the main battery is insufficient to continue to do so, in order to generate electricity and extend the radius action when the battery is completely discharged.
  • a system using the fuel cell is implemented and generates the electrical power necessary for the advancement of the vehicle and therefore for its movement, thus allowing users to make long-distance journeys.
  • the system involving the fuel cell is in particular powered by hydrogen, this hydrogen being able to be stored in liquid form or in gaseous form.
  • this hydrogen is then at a very low temperature, generally at - 253°C, while when it involves its gaseous form hydrogen is under high pressure.
  • the present invention aims to overcome this drawback by proposing a self-regulated liquid hydrogen evaporation process, which makes it possible to recover part of the energy occurring during the liquefaction step, thus increasing the overall efficiency of the fuel cell system. combustible.
  • the main object of the present invention is thus a system for supplying hydrogen to a fuel cell for a vehicle, comprising an evaporator equipped with a supply of hydrogen in liquid form and an evacuation of hydrogen in gaseous form, this evaporator comprising an enclosure within which a porous material is arranged, the enclosure being traversed by a conduit for heat transfer fluid.
  • This system makes it possible to supply energy to the electric vehicle, this energy being supplied by the fuel cell thanks to hydrogen.
  • the hydrogen undergoes evaporation, which allows it to pass from its liquid form to its gaseous form, in which it can supply the fuel cell.
  • evaporation takes place within the evaporator, which comprises a feed through which the hydrogen in liquid form is routed from a tank in which it is stored, and an outlet through which the hydrogen in gaseous form leaves the evaporator, in the direction of the fuel cell.
  • the evaporator comprises an enclosure, which delimits a receptacle within the evaporator, comprising a porous material placed between the supply and the evacuation of the hydrogen.
  • the hydrogen passes through the enclosure by circulating in the porous material according to a capillary phenomenon.
  • the containment is also crossed by a duct, this duct participating in the circulation of a heat transfer fluid in the evaporator.
  • the heat transfer fluid has the particular effect of heating the hydrogen, which therefore evaporates. According to the invention, there is therefore in the enclosure liquid hydrogen unchanged with respect to the state in which it was injected into the enclosure and gaseous hydrogen, heated by the heat transfer fluid.
  • the receptacle delimited by the enclosure can be split into two portions, which are distinguished by the liquid or gaseous state of the hydrogen passing through the porous material by capillarity.
  • the first portion is in the vicinity of the hydrogen supply in liquid form
  • the second portion is in the vicinity of the evacuation of hydrogen in gaseous form and the coolant conduit.
  • the first portion thus corresponds to the portion of the porous material in which hydrogen circulates in liquid form
  • the second portion corresponds to the portion of the porous material in which hydrogen circulates in gaseous form.
  • These two portions are not delimited by a physical separation within the receptacle. It is understood that the volume of each portion can be variable, depending on the temperature of the heat transfer fluid and therefore depending on the volume of hydrogen in liquid form and the volume of hydrogen in gaseous form which circulate in the evaporator.
  • the enclosure comprises two front walls to which the heat transfer fluid conduit is connected, as well as a peripheral side wall connecting the front walls and on which the supply of hydrogen in liquid form and the evacuation of hydrogen in gaseous form are connected.
  • the receptacle of the porous material is delimited by the enclosure, which comprises two front walls and a peripheral side wall. These two front walls are opposite each other, and are both crossed by the heat transfer fluid conduit. This heat transfer fluid conduit thus passes through the receptacle of the evaporator.
  • the peripheral side wall is disposed between the two side walls and connects them.
  • Such a peripheral side wall can in particular be understood as a side face or cylindrical surface if the receptacle has the shape of a cylinder of revolution, or even the continuity of four contiguous planar walls if the receptacle takes the form of a right pad.
  • the peripheral side wall carries both the supply of hydrogen in liquid form and the evacuation of hydrogen in gaseous form. The hydrogen can therefore be transported to the evaporator by crossing the peripheral side wall, then it circulates within this evaporator and leaves it by crossing the peripheral side wall again.
  • the heat transfer fluid conduit comprises an electric heating element.
  • This electrical heating element can for example be a resistive element such as an electrical resistance, or even a heating sheath.
  • This electric heating element is able to heat the heat transfer fluid, thus participating in the evaporation of the hydrogen which passes from its liquid form to its gaseous form.
  • the electric heating element can be useful to prevent the heat transfer fluid from being frozen by the very low temperature of the liquid hydrogen when the vehicle is started.
  • the electric heating element can also heat the hydrogen directly, in addition to the action of the heat transfer fluid.
  • the heat transfer fluid conduit is off-center relative to a median axis of the enclosure passing through the front walls, a shortest distance measured between the heat transfer fluid conduit and the hydrogen evacuation under gaseous form being less than a shortest distance measured between the coolant conduit and the supply of hydrogen in liquid form.
  • Such a median axis can for example correspond to an axis of revolution if the receptacle of the evaporator, delimited by the enclosure, is a cylinder of revolution. It is understood by "off-center" that the heat transfer fluid conduit is not arranged equidistant between the supply of hydrogen in liquid form and the evacuation of hydrogen in gaseous form, but rather close to this evacuation of hydrogen in gaseous form. This makes it possible to ensure that the hydrogen near the evacuation is indeed in gaseous form and that the hydrogen which will be directed to the fuel cell is indeed gaseous.
  • the supply system comprises a turbine, this turbine being arranged between the gaseous hydrogen evacuation conduit and the fuel cell.
  • the hydrogen in gaseous form expands and its pressure decreases.
  • the mechanical pressure energy recovered by the turbine can then be used in particular to operate an electric generator which provides electrical energy for the vehicle, thus contributing to increasing the efficiency of the fuel cell system.
  • the supply system comprises at least one valve able to regulate a pressure within the supply system and being arranged between the evaporator and the turbine.
  • This valve constitutes a means of controlling the pressure. It can be controlled, so that evaporation continues as long as the pressure is below a threshold value.
  • a valve can for example be similar to a valve system.
  • the supply system comprises a first valve able to regulate the pressure in the evaporator.
  • the first valve is in particular arranged between the evaporator and a buffer tank for hydrogen in the gaseous state.
  • the first valve is controlled in opening in order to regulate the pressure and the flow of hydrogen in a tank separate from the liquid hydrogen tank, in particular referred to as a buffer tank.
  • the supply system comprises a second valve placed between the buffer tank and the turbine.
  • the second valve is configured to regulate the pressure and the flow rate of the hydrogen in the gaseous state before the entry of the turbine, where the gas undergoes an expansion due to its passage through the turbine, before supplying the fuel cell.
  • the supply system comprises a control member, for example of the valve type, arranged between the liquid hydrogen tank and the evaporator.
  • the control unit serves in particular to isolate the liquid hydrogen tank from the hydrogen supply system of the fuel cell when the vehicle is parked, before it is started.
  • the heat transfer fluid conduit is part of a thermal regulation system comprising a regulating member, this regulating member being intended to orient the passage of the heat transfer fluid between a heat exchanger and a bypass .
  • the thermal regulation system makes it possible on the one hand to regulate the temperature of the heat transfer fluid, and on the other hand to regulate the temperature of the fuel cell.
  • the thermal regulation system comprises the regulating member, for example a thermostat, according to which the heat transfer fluid will be directed either towards the heat exchanger, or towards a bypass preventing the passage of the heat transfer fluid through this exchanger. heat which may in particular be a radiator.
  • the regulating member makes it possible to bypass, that is to say to bypass the heat exchanger, the heat transfer fluid not exchanging calories within this heat exchanger and being able to improve the efficiency. hydrogen evaporation in the containment.
  • the thermal regulation system comprises a first branch able to regulate the temperature of the fuel cell.
  • This first branch participates in increasing the temperature of the heat transfer fluid to an optimum temperature for the operation of the fuel cell, which is close to 50 to 70°C.
  • the regulating member closes the passage of the heat transfer fluid through the heat exchanger, namely here a cooling radiator.
  • the heat transfer fluid circulating in the first branch is not cooled, advantageously causing a rise in temperature of the fuel cell.
  • the thermal regulation system comprises a second branch able to regulate the temperature within the evaporator.
  • the thermal regulation system comprises an adjustable valve, in particular of the three-way valve type, interposed between the first branch and the second branch and which is configured to regulate the flow rate of heat transfer fluid within the second branch.
  • the heat required to evaporate the liquid hydrogen depends on the consumption of the hydrogen, and the temperature of the heat transfer fluid circulating in the second branch, in particular through the evaporator.
  • the adjustable valve located at the junction of the first branch and the second branch is capable of regulating the flow rate of the heat transfer fluid in order to bring the temperature of the hydrogen in the gaseous state at the outlet of the evaporator substantially to the fuel cell temperature.
  • the invention also relates to a process for supplying hydrogen to a fuel cell, comprising a step for conveying the hydrogen to the evaporator, a step for evaporating and hydrogen pressure and a step for transmitting the hydrogen to the fuel cell.
  • the hydrogen delivery step corresponds to the movement of hydrogen from the tank in which it is stored in liquid form to within the evaporator.
  • the hydrogen evaporation step takes place within this evaporator, where it changes from a liquid state to a gaseous state, which generates an increase in its pressure.
  • This evaporation step requires the heating of the hydrogen, which is carried out in particular by means of the heat transfer fluid.
  • the stage of transmission of hydrogen to the fuel cell corresponds to the transport of hydrogen in gaseous form from the evaporator to the fuel cell. For this purpose, it passes through the turbine, which allows the recovery of mechanical pressure energy.
  • the supply method comprises a pressure control sub-step, this control sub-step being at least partly ensured by the at least one valve.
  • This pressure control sub-stage occurs during the stage of transmission of hydrogen in gaseous form to the fuel cell. Opening the valve allows hydrogen gas to be released when it is at a suitable pressure for supplying the fuel cell, and closing this valve allows the pressure of the hydrogen gas to rise within of the containment before allowing it to be evacuated to the fuel cell.
  • the invention finally relates to an electric vehicle being equipped with a supply system as described previously, and/or being supplied with hydrogen according to the supply method as described previously.
  • FIG. i schematically illustrates a fuel cell system, comprising a system for supplying this fuel cell by hydrogen according to the invention
  • FIG. 2 shows a cross-sectional view of a receptacle within which a heat transfer fluid and hydrogen circulate
  • FIG. 3 is a schematic representation of the receptacle of FIG. 2 according to a top view, showing the distribution between hydrogen in liquid form and hydrogen in gaseous form;
  • FIG. 4 is another schematic representation of the receptacle of FIG. 2 according to a top view, the distribution between hydrogen in liquid form and hydrogen in gaseous form being different from that of FIG. 3;
  • FIG. 5 schematically illustrates a variant of the fuel cell system of FIG. 1, comprising a system for supplying this fuel cell with hydrogen according to the invention.
  • variants of the invention may be associated with each other, in various combinations, insofar as they are not incompatible or exclusive with respect to each other.
  • variants of the invention may be imagined comprising only a selection of characteristics described below in isolation from the other characteristics described, if this selection of characteristics is sufficient to confer a technical advantage and/or to differentiate the invention. compared to the prior art.
  • heat transfer fluid can refer to any heat transfer fluid or liquid, provided that this fluid or liquid has the effect of cooling or heating a fuel cell system.
  • FIG. 1 thus illustrates, schematically, a fuel cell 1 system 16 comprising a hydrogen supply system 17 for this fuel cell 1 according to the invention.
  • the fuel cell i makes it possible to supply an electric vehicle with electrical energy when a battery of this vehicle is discharged.
  • the fuel cell i operates using hydrogen in gaseous form, which according to the invention is obtained from hydrogen stored in liquid form, for reasons of space in particular.
  • Hydrogen in liquid form is here stored in storage tank 2, which is an adiabatic tank where the hydrogen is at a temperature less than or equal to -253°C, such a temperature corresponding to the dew point of hydrogen at atmospheric pressure, i.e. a temperature at which it is in liquid form.
  • the process for supplying the fuel cell 1 with hydrogen comprises a step for conveying this hydrogen, during which the hydrogen in liquid form is conveyed from its storage tank 2 to an evaporator 4. It passes through for this purpose a control member 6, for example of the valve type, which makes it possible to regulate the flow of hydrogen.
  • the hydrogen in liquid form enters the evaporator 4 through a tube 610, which corresponds to a supply of hydrogen in liquid form 61.
  • the process for supplying the fuel cell 1 continues with an evaporation step, during which the hydrogen in liquid form is transformed into hydrogen in gaseous form under the effect of an evaporation phenomenon, which results from an increase in its temperature and leads to an increase in pressure.
  • the means implemented to carry out this evaporation step will be more particularly described below.
  • the hydrogen then leaves the evaporator 4 through a channel 620, which corresponds to an evacuation of hydrogen in gaseous form 62.
  • the process for supplying the fuel cell 1 finally comprises a step for supplying this fuel cell 1.
  • a first valve 5a which constitutes a means of pressure control.
  • the first valve 5a can be controlled and configured to open only when the pressure of the hydrogen gas reaches a threshold value, which is here below a critical point of 13 bars, for example a value between 10 and 12 bars . Below this threshold value, the first valve 5a remains closed and thus the evaporation phenomenon continues within the evaporator 4, until the hydrogen has reached the required pressure. It is therefore understood that the first valve 5a intervenes in a sub-step of the process for supplying the fuel cell 1 with hydrogen, namely a pressure control sub-step.
  • the hydrogen supply system 17 of the fuel cell 1 can also comprise a buffer tank 7, which also participates in the sub-step pressure control.
  • the buffer tank 7 is thus arranged downstream of this first valve 5a according to the direction of flow of the hydrogen towards the fuel cell 1.
  • the first valve 5a opens and the hydrogen enters this buffer tank 7.
  • a second valve 5b arranged downstream of the buffer tank 7 according to the direction of flow of the hydrogen towards the fuel cell 1, allows control of the pressure upstream of the turbine and of the flow of hydrogen in the state gas in the turbine.
  • This turbine 3 is arranged between the channel 620 for discharging hydrogen in gaseous form 62 and the fuel cell 1, and more precisely between the second valve 5b and the fuel cell 1.
  • the turbine has the role of expanding the hydrogen which is in gaseous form. Consequently, its pressure decreases, so as to reach an optimum pressure for the operation of the fuel cell 1.
  • the mechanical energy released by such a decrease in pressure is recovered by the turbine 3. This mechanical energy can be used in different ways. manners.
  • the mechanical energy can thus be used to operate an air compressor 10, capable of recovering ambient air in order to supply the fuel cell 1 with oxygen.
  • the mechanical energy generated is greater than the mechanical energy needed to operate the air compressor 10, it can be used to operate an electric generator 20 which provides electric power to the vehicle.
  • the hydrogen in gaseous form can be routed to fuel cell 1 through a pipe 21 to produce electrical energy there.
  • the evaporator 4 is represented schematically in FIGS. 2 to 4.
  • FIG. 2 is a representation of a section of this evaporator 4 according to a front view
  • FIGS. 3 and 4 are top views which represent distributions different between hydrogen in liquid form and hydrogen in gaseous form.
  • the evaporator 4 comprises a receptacle 40 delimited by an enclosure 41.
  • This enclosure 41 consists of two front walls 46 and a peripheral side wall 47, which is arranged between the front walls 46 and connects them. These front walls 46 are here parallel and opposite to each other.
  • the peripheral side wall 47 means a side face or cylindrical surface of this cylindrical shape. It is also possible to envisage the evaporator 4 taking the form of a straight block, in which case the peripheral side wall 47 would correspond to the continuity of four contiguous side walls of this straight block.
  • the evaporator 4 is equipped with a supply of hydrogen in liquid form 61 and an evacuation of hydrogen in gaseous form 62.
  • This supply of hydrogen in liquid form 61 and this evacuation of hydrogen in gaseous form 62 are connected to the peripheral side wall 47, via a tube 610 and a channel 620 respectively.
  • the hydrogen in liquid form is thus conveyed to the evaporator 4 by the tube 610 for supplying hydrogen in liquid form , and it leaves this evaporator 4 in gaseous form through the channel 620 for discharging hydrogen in gaseous form.
  • the receptacle 40 of the evaporator 4 and its enclosure 41 are crossed right through by a heat transfer fluid conduit 45, within which this heat transfer fluid circulates.
  • This heat transfer fluid duct 45 is connected to each of the front walls 46, and extends within the enclosure 41 in the direction of a median axis M.
  • This median axis M may for example correspond, if the receptacle 40 has a cylinder shape, at the axis of revolution of this cylinder.
  • the heat transfer fluid conduit 45 is associated with a resistive heating element 44, which in the example shown, consists of a resistive wire housed within the cooling fluid conduit. This resistive heating element 44 participates, in association with the heat transfer fluid, in heating the hydrogen in order to evaporate it and thus to make it pass from its liquid form to its gaseous form, in which it is able to supply the fuel cell.
  • fuel 1 fuel 1.
  • a porous material which is therefore also crossed by the heat transfer fluid conduit 45.
  • the configuration of this porous material makes it possible to increase the exchange surfaces within the evaporator 4.
  • This porous material is able to be crossed by hydrogen according to a phenomenon of capillarity.
  • the hydrogen in fact arrives in the evaporator 4 through the hydrogen supply tube 610 in liquid form, and this liquid hydrogen is sucked up by capillarity within the evaporator 4.
  • Capillarity is possible due to the coexistence of hydrogen in liquid form and in gaseous form. When there is no longer either hydrogen in liquid form or hydrogen in gaseous form, the capillarity phenomenon no longer occurs and the arrival of liquid hydrogen within the evaporator 4 is therefore prevented.
  • the hydrogen supply system 17 is therefore self-regulated during the step of conveying this hydrogen to the evaporator 4.
  • first portion 42 corresponding to the portion of the porous material where the hydrogen circulates in its liquid form
  • second portion 43 corresponding to the portion of the porous material where hydrogen circulates in its gaseous form.
  • the volumes of the two portions are variable, and depend respectively on the proportion of liquid hydrogen and gaseous hydrogen in the receptacle 40 of the evaporator 4.
  • FIGS. 3 and 4 illustrate these differences in proportion, the second portion 43 corresponding to the hydrogen gas being more important in figure 4 than in figure 3.
  • This proportion of liquid hydrogen and gaseous hydrogen is influenced by the action of the heat transfer fluid, which circulates within the heat transfer fluid conduit 45, and of the resistive heating element 44 which is also placed in the heat transfer fluid conduit 45 Indeed, the heat transfer fluid and the resistive heating element 44 heating the hydrogen, they influence the proportion of liquid hydrogen and gaseous hydrogen since such heating results in the evaporation of this hydrogen. Consequently, the delimitation between the first portion 42 and the second portion 43 changes according to the temperature differential between the heat transfer fluid and the liquid hydrogen.
  • the resistive heating element 44 is able to heat the hydrogen in different ways. It can thus heat it indirectly, by heating the heat transfer fluid which in turn heats the hydrogen, or directly, since it heats the porous material in which the hydrogen circulates in its vicinity.
  • the resistive heating element has the particular function of heating the heat transfer fluid within the conduit, in particular when the vehicle is started, in order to ensure that the heat transfer fluid, which is in the vicinity of hydrogen in liquid form at -253 °C, does not freeze.
  • the resistive heating element 44 is therefore very particularly used during the implementation of the fuel cell system 16 1.
  • the heat transfer fluid can thus liquefy, passing from the solid state in which it is frozen during stopping the vehicle in the liquid state in which it can circulate.
  • the resistive heating element can nevertheless be used when the heat transfer fluid is liquefied, thus accelerating the evaporation of the hydrogen.
  • FIGS 3 and 4 also illustrate the fact that the heat transfer fluid duct 45 is off-center with respect to the central axis M passing through the front walls 46, these front walls being visible in Figure 2.
  • a shortest distance Di measured between the heat transfer fluid conduit 45 and the hydrogen gas discharge 62 is less than a shortest distance D2 measured between the heat transfer fluid conduit 45 and the hydrogen supply in liquid form 61.
  • the hydrogen in gaseous form is in fact formed more rapidly in the vicinity of the peripheral side wall 47 carrying the evacuation of hydrogen in gaseous form 62, and therefore gradually the liquid hydrogen arriving near this side wall device 47 carrying the evacuation of hydrogen in gaseous form 62 is vaporized.
  • the hydrogen supply system 17 of the fuel cell 1 is thus formed, in particular, of the evaporator 4, of the turbine 3 and of the fuel cell 1.
  • the system 16 of fuel cell 1 comprises, in parallel of this hydrogen supply system 17, a thermal regulation system 18 visible in FIG. 1.
  • This thermal regulation system 18 makes it possible to regulate the temperature both within the evaporator 4, by bringing the heat transfer fluid to an appropriate temperature, and the fuel cell 1.
  • FIG. 1 A first simplified embodiment of the thermal regulation system 18 is illustrated in FIG. 1.
  • Regulating the temperature of the heat transfer fluid is necessary, in particular to participate in preventing freezing of the heat transfer fluid within the heat transfer fluid conduit 45 as explained above.
  • the conduit of heat transfer fluid 45 is thus integrated into the thermal regulation system 18, which also involves a regulating member 34.
  • This regulating member 34 for example a thermostat, has the function of directing the heat transfer fluid along two different paths depending on whether its temperature is sufficient or not.
  • the regulating member 34 directs the heat transfer fluid towards a bypass or bypass. 35. This bypass 35 allows the heat transfer fluid to bypass the heat exchanger 30.
  • the thermal regulation system 18 makes it possible, through the regulating member 34, to regulate both the temperature of the heat transfer fluid which passes through the fuel cell 1 and that of the heat transfer fluid which passes through the evaporator 4. This is explained by the configuration of this thermal regulation system 18, which comprises several branches.
  • a first branch 36 is dedicated to regulating the temperature of the fuel cell 1.
  • the heat transfer fluid circulating in this first branch 36 can thus regulate the temperature of the fuel cell 1, and in particular reheat it so that it reaches its optimum temperature, namely between 50 and 70 °C approximately.
  • a second branch 38 participates in the regulation of the temperature within the evaporator 4.
  • the heat transfer fluid circulating in this second branch 38 is heated by the fuel cell so as to be able in turn to heat the hydrogen present within the evaporator 4, and therefore so as to be able to evaporate it.
  • FIG. 5 comprises, as before, an evaporator comprising an enclosure within which a porous material is placed, the enclosure being traversed by a heat transfer fluid conduit , and which differs in particular in the design of the thermal regulation system and the number and arrangement of the branches which constitute it. It should be noted that a selection of the modifications present on the fuel cell system of the variant illustrated in FIG. 5 and which will be described below could be implemented without departing from the invention.
  • the second branch 38 is connected at one of its ends to the first branch via an adjustable valve 50, for example of the three-way valve type.
  • the regulating member 34 for example a thermostat, makes it possible to regulate both the temperature of the heat transfer fluid which passes through the fuel cell 1 and that of the heat transfer fluid which passes through the evaporator 4, while the valve adjustable 50 makes it possible to regulate the flow rate of the coolant which passes through the evaporator 4, by making it possible to derive part of the flow rate, that is to say from 0 to 100% of the flow rate, coming mainly from the fuel cell 1, by branch 38 connected to adjustable valve 50, in the direction of evaporator 4.
  • the quantity of hydrogen varies, in particular increases, so that the adjustable valve 50 modulates the opening section of its outlet in fluid connection with the bypass branch passing through the evaporator , which tends to increase the flow rate of the coolant in the evaporator.
  • the heat exchange carried out within the evaporator tends to increase the quantity of hydrogen in the gaseous state at the outlet of the evaporator 4-
  • the fuel cell system in this variant also differs from the above in that it comprises a third branch 37 on which is arranged a cooler 12 of compressed air circulating in the circuit. fuel cell air supply i.
  • the cooler 12 cools the compressed air to increase the performance of the fuel cell so that it delivers increased electrical power without affecting its size.
  • the fuel cell system in this variant also differs in the presence of an additional branch in which is placed an expansion tank 33 of the water circuit, which can in particular form a bypass branch of the radiator 30.
  • the flow rate of heat transfer fluid circulating in the expansion vessel 33 is lower than that of the fluid circulating in the second branch 38.
  • This additional branch, or bypass branch makes it possible to limit the rise in pressure of the circuit when the coolant expands with the temperature.
  • the expansion tank allows the circuit to be filled with heat transfer fluid. It also allows degassing of the circuit, in particular after emptying.
  • a fuel cell system according to the invention may comprise, as illustrated in FIG. 5, at least one of these additional elements, including a filter 11, a humidity exchanger 13 or a hydrogen recycling.
  • the filter 11 is arranged upstream of the compressor 10 of the air supply circuit to eliminate unwanted particles for the optimal operation of the fuel cell.
  • the air/air humidity exchanger 13 is intended to transmit the humidity of the air leaving the fuel cell to the air entering the fuel cell.
  • the electrochemical reaction of hydrogen with oxygen produces water, the air leaving the cell is thus depleted in oxygen but loaded with humidity.
  • the exchanger 13 allows a transfer of humidity from the outgoing air to the incoming air, which tends to improve the operation of the cell.
  • the circuit for recycling the hydrogen leaving the cell comprises a return branch in which is placed a device 8 for sucking in the hydrogen which can be a nozzle or a pump.
  • the hydrogen circulating through the fuel cell 1 generally not being consumed In its entirety, the recycling circuit aims to reintroduce the remaining hydrogen at the input of the fuel cell as it is present at the output.
  • the present invention thus proposes a system for supplying hydrogen to a fuel cell involving a self-regulated evaporation process, which makes it possible to store hydrogen in liquid form, and which makes it possible to compensate for the energy consumption that has occurred during the stage of liquefaction of the hydrogen necessary for its storage.
  • a power supply system thus makes it possible to optimize the overall efficiency of the fuel cell system.
  • the present invention cannot however be limited to the means and configurations described and illustrated here and it also extends to any equivalent means and configuration as well as to any technically effective combination of such means.

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Abstract

The present invention relates to a system (17) for supplying hydrogen to a fuel cell (1) for a vehicle, comprising an evaporator (4) equipped with a supply (61) for hydrogen in liquid form and with a discharge (62) for hydrogen in gaseous form, this evaporator (4) comprising an enclosure within which a porous material is arranged, the enclosure being traversed by a heat-transfer fluid duct (45).

Description

Titre ■ Système d’alimentation en hydrogène d’une pile à combustibleTitle ■ Hydrogen supply system of a fuel cell
La présente invention concerne le domaine des véhicules électriques, et plus particulièrement les systèmes d’alimentation en énergie de ces véhicules électriques. The present invention relates to the field of electric vehicles, and more particularly to the energy supply systems of these electric vehicles.
On entend dans la présente demande par « véhicules électriques » à la fois les véhicules purement électriques, pour lesquels la seule source d’alimentation est une source d’énergie électrique, et les véhicules hybrides, qui associent à cette source d’énergie électrique une source d’énergie thermique. A ce jour, ces véhicules électriques présentent, par rapport aux véhicules thermiques conventionnels, une autonomie réduite qui peut être préjudiciable aux utilisateurs de véhicules électriques, notamment lorsque ceux-ci souhaitent effectuer de longs trajets. In the present application, the term “electric vehicles” means both purely electric vehicles, for which the only power source is a source of electrical energy, and hybrid vehicles, which combine this source of electrical energy with a thermal energy source. To date, these electric vehicles have, compared to conventional thermal vehicles, a reduced autonomy which can be detrimental to users of electric vehicles, in particular when they wish to make long journeys.
L’autonomie peut être améliorée en augmentant la capacité des batteries qui alimentent les véhicules ou leur quantité, mais de telles augmentations présentent un coût élevé et peuvent par ailleurs poser des problèmes d’encombrement. Range can be improved by increasing the capacity or quantity of the batteries that power the vehicles, but such increases come at a high cost and can also cause congestion issues.
Une autre solution pour augmenter l’autonomie est d’alimenter la batterie, en plus d’une source d’énergie externe, par une source d’énergie interne au véhicule, comme par exemple une pile à combustible qui peut alors être utilisée comme prolongateur d’autonomie. La pile à combustible est électriquement montée en parallèle de la batterie. Le moteur électrique est alimenté en premier lieu par la batterie et, le cas échéant, par la pile à combustible lorsque la charge de la batterie principale est insuffisante pour continuer à le faire, afin de produire de l'électricité et d'étendre le rayon d'action lorsque la batterie est totalement déchargée. Dans ce cas, un système utilisant la pile à combustible est mis en œuvre et génère la puissance électrique nécessaire à l’avancement du véhicule et donc à son déplacement, permettant ainsi aux utilisateurs d’effectuer des trajets de longue distance.Another solution to increase the autonomy is to supply the battery, in addition to an external energy source, with an energy source internal to the vehicle, such as for example a fuel cell which can then be used as an extender. autonomy. The fuel cell is electrically connected in parallel with the battery. The electric motor is powered first by the battery and, if necessary, by the fuel cell when the charge of the main battery is insufficient to continue to do so, in order to generate electricity and extend the radius action when the battery is completely discharged. In this case, a system using the fuel cell is implemented and generates the electrical power necessary for the advancement of the vehicle and therefore for its movement, thus allowing users to make long-distance journeys.
Le système faisant intervenir la pile à combustible est notamment alimenté par de l’hydrogène, cet hydrogène pouvant être stocké sous forme liquide ou sous forme gazeuse. Lorsque le stockage d’hydrogène fait intervenir sa forme liquide, cet hydrogène est alors à très basse température, généralement à - 253 °C, tandis que lorsqu’il fait intervenir sa forme gazeuse l’hydrogène est sous forte pression. The system involving the fuel cell is in particular powered by hydrogen, this hydrogen being able to be stored in liquid form or in gaseous form. When hydrogen storage involves its liquid form, this hydrogen is then at a very low temperature, generally at - 253°C, while when it involves its gaseous form hydrogen is under high pressure.
Il existe dans l’art antérieur des systèmes d’alimentation en hydrogène pour lesquels un échangeur est placé en sortie de ce stockage d’hydrogène, permettant ainsi de réchauffer l’hydrogène soit, s’il est stocké sous forme liquide, afin qu’il s’évapore et atteigne une température proche de la température nécessaire pour faire fonctionner la pile à combustible, généralement entre o et 70 °C, soit, s’il est stocké sous forme gazeuse, afin qu’il atteigne une pression compatible avec le fonctionnement de la pile à combustible. On comprend ainsi que lorsque l’hydrogène est sous forme liquide, il est nécessaire de mettre en œuvre un processus d’évaporation, la pile à combustible fonctionnant avec de l’hydrogène sous forme gazeuse. L’hydrogène sous forme liquide, bien qu’il permette d’obvier à des contraintes d’encombrement, consomme cependant beaucoup d’énergie, notamment lors de l’étape de liquéfaction qui précède son stockage et qui vise à faire passer l’hydrogène gazeux aux pression et température ambiantes à de l’hydrogène liquide à -253 °C. In the prior art, there are hydrogen supply systems for which an exchanger is placed at the outlet of this hydrogen storage, thus making it possible to heat the hydrogen either, if it is stored in liquid form, so that it evaporates and reaches a temperature close to the temperature necessary to operate the fuel cell, generally between 0 and 70°C, i.e., if it is stored in gaseous form, so that it reaches a pressure compatible with the fuel cell operation. It is thus understood that when the hydrogen is in liquid form, it is necessary to implement an evaporation process, the fuel cell operating with hydrogen in gaseous form. Hydrogen in liquid form, although it makes it possible to overcome space constraints, nevertheless consumes a lot of energy, in particular during the liquefaction stage which precedes its storage and which aims to pass the hydrogen gas at ambient pressure and temperature to liquid hydrogen at -253°C.
La présente invention vise à pallier cet inconvénient en proposant un processus autorégulé d’évaporation de l’hydrogène liquide, qui permet de récupérer une partie d’énergie survenue lors de l’étape de liquéfaction, augmentant ainsi le rendement global du système de pile à combustible.The present invention aims to overcome this drawback by proposing a self-regulated liquid hydrogen evaporation process, which makes it possible to recover part of the energy occurring during the liquefaction step, thus increasing the overall efficiency of the fuel cell system. combustible.
La présente invention a ainsi pour principal objet un système d’alimentation en hydrogène d’une pile à combustible pour véhicule, comportant un évaporateur équipé d’une alimentation en hydrogène sous forme liquide et d’une évacuation d’hydrogène sous forme gazeuse, cet évaporateur comprenant une enceinte au sein de laquelle est disposé un matériau poreux, l’enceinte étant traversée par un conduit de fluide caloporteur. The main object of the present invention is thus a system for supplying hydrogen to a fuel cell for a vehicle, comprising an evaporator equipped with a supply of hydrogen in liquid form and an evacuation of hydrogen in gaseous form, this evaporator comprising an enclosure within which a porous material is arranged, the enclosure being traversed by a conduit for heat transfer fluid.
Ce système permet de fournir de l’énergie au véhicule électrique, cette énergie étant fournie par la pile à combustible grâce à l’hydrogène. L’hydrogène subit à cet effet une évaporation, qui permet de le faire passer de sa forme liquide à sa forme gazeuse, dans laquelle il peut alimenter la pile à combustible. Une telle évaporation s’opère au sein de l’évaporateur, qui comprend une alimentation par laquelle l’hydrogène sous forme liquide est acheminé depuis un réservoir dans lequel il est stocké, et une évacuation par laquelle l’hydrogène sous forme gazeuse quitte l’évaporateur, en direction de la pile à combustible. This system makes it possible to supply energy to the electric vehicle, this energy being supplied by the fuel cell thanks to hydrogen. For this purpose, the hydrogen undergoes evaporation, which allows it to pass from its liquid form to its gaseous form, in which it can supply the fuel cell. Such evaporation takes place within the evaporator, which comprises a feed through which the hydrogen in liquid form is routed from a tank in which it is stored, and an outlet through which the hydrogen in gaseous form leaves the evaporator, in the direction of the fuel cell.
Tel qu’évoqué, selon l’invention, l’évaporateur comprend une enceinte, qui délimite un réceptacle au sein de l’évaporateur, comportant un matériau poreux disposé entre l’alimentation et l’évacuation de l’hydrogène. As mentioned, according to the invention, the evaporator comprises an enclosure, which delimits a receptacle within the evaporator, comprising a porous material placed between the supply and the evacuation of the hydrogen.
L’hydrogène traverse l’enceinte en circulant dans le matériau poreux selon un phénomène de capillarité. L’enceinte est en outre traversé par un conduit, ce conduit participant à la circulation d’un fluide caloporteur dans l’évaporateur. The hydrogen passes through the enclosure by circulating in the porous material according to a capillary phenomenon. The containment is also crossed by a duct, this duct participating in the circulation of a heat transfer fluid in the evaporator.
Le fluide caloporteur a notamment pour effet de réchauffer l’hydrogène, qui de ce fait s’évapore. Selon l’invention, on a donc dans l’enceinte de l’hydrogène liquide inchangé par rapport à l’état dans lequel il a été injecté dans l’enceinte et de l’hydrogène gazeux, réchauffé par le fluide caloporteur.The heat transfer fluid has the particular effect of heating the hydrogen, which therefore evaporates. According to the invention, there is therefore in the enclosure liquid hydrogen unchanged with respect to the state in which it was injected into the enclosure and gaseous hydrogen, heated by the heat transfer fluid.
Le réceptacle délimité par l’enceinte peut être scindé en deux portions, qui se distinguent par l’état liquide ou gazeux de l’hydrogène traversant le matériau poreux par capillarité. La première portion est au voisinage de l’alimentation en hydrogène sous forme liquide, et la deuxième portion est au voisinage de l’évacuation d’hydrogène sous forme gazeuse et du conduit de fluide caloporteur. La première portion correspond ainsi à la portion du matériau poreux où circule de l’hydrogène sous forme liquide, tandis que la deuxième portion correspond à la portion du matériau poreux où circule de l’hydrogène sous forme gazeuse. Ces deux portions ne sont pas délimitées par une séparation physique au sein du réceptacle. On comprend que le volume de chaque portion peut être variable, en fonction de la température du fluide caloporteur et donc en fonction du volume d’hydrogène sous forme liquide et du volume d’hydrogène sous forme gazeuse qui circulent dans l’évaporateur.The receptacle delimited by the enclosure can be split into two portions, which are distinguished by the liquid or gaseous state of the hydrogen passing through the porous material by capillarity. The first portion is in the vicinity of the hydrogen supply in liquid form, and the second portion is in the vicinity of the evacuation of hydrogen in gaseous form and the coolant conduit. The first portion thus corresponds to the portion of the porous material in which hydrogen circulates in liquid form, while the second portion corresponds to the portion of the porous material in which hydrogen circulates in gaseous form. These two portions are not delimited by a physical separation within the receptacle. It is understood that the volume of each portion can be variable, depending on the temperature of the heat transfer fluid and therefore depending on the volume of hydrogen in liquid form and the volume of hydrogen in gaseous form which circulate in the evaporator.
Selon une caractéristique de l’invention, l’enceinte comprend deux parois frontales sur lesquelles est raccordé le conduit de fluide caloporteur, ainsi qu’une paroi latérale périphérique reliant les parois frontales et sur laquelle sont raccordées l’alimentation en hydrogène sous forme liquide et l’évacuation d’hydrogène sous forme gazeuse. According to one characteristic of the invention, the enclosure comprises two front walls to which the heat transfer fluid conduit is connected, as well as a peripheral side wall connecting the front walls and on which the supply of hydrogen in liquid form and the evacuation of hydrogen in gaseous form are connected.
On comprend que le réceptacle du matériau poreux est délimité par l’enceinte, qui comprend deux parois frontales et une paroi latérale périphérique. Ces deux parois frontales sont opposées l’une à l’autre, et sont toutes deux traversées par le conduit de fluide caloporteur. Ce conduit de fluide caloporteur traverse ainsi le réceptacle de l’évaporateur. La paroi latérale périphérique est disposée entre les deux parois latérales et les relie. Une telle paroi latérale périphérique peut notamment s’entendre d’une face latérale ou surface cylindrique si le réceptacle a la forme d’un cylindre de révolution, ou encore de la continuité de quatre parois planes contigües si le réceptacle prend la forme d’un pavé droit. La paroi latérale périphérique porte à la fois l’alimentation en hydrogène sous forme liquide et l’évacuation d’hydrogène sous forme gazeuse. L’hydrogène peut donc être acheminé jusqu’à l’évaporateur en traversant la paroi latérale périphérique, puis il circule au sein de cet évaporateur et le quitte en traversant de nouveau la paroi latérale périphérique. It is understood that the receptacle of the porous material is delimited by the enclosure, which comprises two front walls and a peripheral side wall. These two front walls are opposite each other, and are both crossed by the heat transfer fluid conduit. This heat transfer fluid conduit thus passes through the receptacle of the evaporator. The peripheral side wall is disposed between the two side walls and connects them. Such a peripheral side wall can in particular be understood as a side face or cylindrical surface if the receptacle has the shape of a cylinder of revolution, or even the continuity of four contiguous planar walls if the receptacle takes the form of a right pad. The peripheral side wall carries both the supply of hydrogen in liquid form and the evacuation of hydrogen in gaseous form. The hydrogen can therefore be transported to the evaporator by crossing the peripheral side wall, then it circulates within this evaporator and leaves it by crossing the peripheral side wall again.
Selon une autre caractéristique de l’invention, le conduit de fluide caloporteur comprend un élément électrique de chauffage. According to another characteristic of the invention, the heat transfer fluid conduit comprises an electric heating element.
Cet élément électrique de chauffage peut par exemple être un élément résistif tel qu’une résistance électrique, ou encore une gaine chauffante. Cet élément électrique de chauffage est apte à chauffer le fluide caloporteur, participant ainsi à l’évaporation de l’hydrogène qui passe de sa forme liquide à sa forme gazeuse. Notamment, l’élément électrique de chauffage peut être utile pour éviter que le fluide caloporteur soit, au démarrage du véhicule, congelé par la température très basse de l’hydrogène liquide. L’élément électrique de chauffage peut également réchauffer l’hydrogène directement, en appoint de l’action du fluide caloporteur. This electrical heating element can for example be a resistive element such as an electrical resistance, or even a heating sheath. This electric heating element is able to heat the heat transfer fluid, thus participating in the evaporation of the hydrogen which passes from its liquid form to its gaseous form. In particular, the electric heating element can be useful to prevent the heat transfer fluid from being frozen by the very low temperature of the liquid hydrogen when the vehicle is started. The electric heating element can also heat the hydrogen directly, in addition to the action of the heat transfer fluid.
Selon une caractéristique de l’invention, le conduit de fluide caloporteur est décentré par rapport à un axe médian de l’enceinte traversant les parois frontales, une distance la plus courte mesurée entre le conduit de fluide caloporteur et l’évacuation d’hydrogène sous forme gazeuse étant inférieure à une distance la plus courte mesurée entre le conduit de fluide caloporteur et l’alimentation en hydrogène sous forme liquide. According to one characteristic of the invention, the heat transfer fluid conduit is off-center relative to a median axis of the enclosure passing through the front walls, a shortest distance measured between the heat transfer fluid conduit and the hydrogen evacuation under gaseous form being less than a shortest distance measured between the coolant conduit and the supply of hydrogen in liquid form.
Un tel axe médian peut par exemple correspondre à un axe de révolution si le réceptacle de l’évaporateur, délimité par l’enceinte, est un cylindre de révolution. On comprend par « décentré » que le conduit de fluide caloporteur n’est pas disposé à équidistance entre l’alimentation en hydrogène sous forme liquide et l’évacuation d’hydrogène sous forme gazeuse, mais plutôt à proximité de cette évacuation d’hydrogène sous forme gazeuse. Cela permet de s’assurer que l’hydrogène à proximité de l’évacuation est bien sous forme gazeuse et que l’hydrogène qui va être dirigé vers la pile à combustible est bien gazeux. Such a median axis can for example correspond to an axis of revolution if the receptacle of the evaporator, delimited by the enclosure, is a cylinder of revolution. It is understood by "off-center" that the heat transfer fluid conduit is not arranged equidistant between the supply of hydrogen in liquid form and the evacuation of hydrogen in gaseous form, but rather close to this evacuation of hydrogen in gaseous form. This makes it possible to ensure that the hydrogen near the evacuation is indeed in gaseous form and that the hydrogen which will be directed to the fuel cell is indeed gaseous.
Selon une autre caractéristique de l’invention, le système d’alimentation comprend une turbine, cette turbine étant disposée entre le conduit d’évacuation en hydrogène sous forme gazeuse et la pile à combustible. According to another characteristic of the invention, the supply system comprises a turbine, this turbine being arranged between the gaseous hydrogen evacuation conduit and the fuel cell.
Au sein de la turbine, l’hydrogène sous forme gazeuse se détend et sa pression diminue. L’énergie mécanique de pression récupérée par la turbine peut alors notamment être utilisée pour faire fonctionner un générateur électrique qui fournit l’énergie électrique pour le véhicule, contribuant ainsi à l’augmentation du rendement du système de pile à combustible. Within the turbine, the hydrogen in gaseous form expands and its pressure decreases. The mechanical pressure energy recovered by the turbine can then be used in particular to operate an electric generator which provides electrical energy for the vehicle, thus contributing to increasing the efficiency of the fuel cell system.
Selon une caractéristique de l’invention, le système d’alimentation comprend au moins une vanne apte à réguler une pression au sein du système d’alimentation et étant disposée entre l’évaporateur et la turbine. According to one characteristic of the invention, the supply system comprises at least one valve able to regulate a pressure within the supply system and being arranged between the evaporator and the turbine.
Cette vanne constitue un moyen de contrôle de la pression. Elle peut être pilotée, de façon que l’évaporation se poursuit tant que la pression est inférieure à une valeur seuil. Une telle vanne peut par exemple s’apparenter à un système de clapet. This valve constitutes a means of controlling the pressure. It can be controlled, so that evaporation continues as long as the pressure is below a threshold value. Such a valve can for example be similar to a valve system.
Selon une autre caractéristique de l’invention, le système d’alimentation comprend une première vanne apte à réguler la pression dans l’évaporateur. La première vanne est notamment disposée entre l’évaporateur et un réservoir tampon de l’hydrogène en l’état gazeux. Selon la demande en quantité d’hydrogène par la pile à combustible, la première vanne est pilotée en ouverture afin de réguler la pression et le débit d’hydrogène dans un réservoir distinct du réservoir d’hydrogène liquide, notamment qualifié de réservoir tampon. According to another characteristic of the invention, the supply system comprises a first valve able to regulate the pressure in the evaporator. The first valve is in particular arranged between the evaporator and a buffer tank for hydrogen in the gaseous state. Depending on the demand for quantity of hydrogen by the fuel cell, the first valve is controlled in opening in order to regulate the pressure and the flow of hydrogen in a tank separate from the liquid hydrogen tank, in particular referred to as a buffer tank.
Selon une autre caractéristique de l’invention, le système d’alimentation comprend une deuxième vanne disposée entre le réservoir tampon et la turbine. La deuxième vanne est configurée pour réguler la pression et le débit de l’hydrogène à l’état gazeux avant l’entrée de la turbine, où le gaz subit une détente du fait de son passage au travers de la turbine, avant d’alimenter la pile à combustible. Une telle architecture permet avantageusement de maintenir constante la pression au niveau de la pile, préférentiellement de l’ordre de 2 bars absolue. According to another characteristic of the invention, the supply system comprises a second valve placed between the buffer tank and the turbine. The second valve is configured to regulate the pressure and the flow rate of the hydrogen in the gaseous state before the entry of the turbine, where the gas undergoes an expansion due to its passage through the turbine, before supplying the fuel cell. Such an architecture advantageously makes it possible to keep the pressure at the stack level constant, preferably of the order of 2 bars absolute.
Selon une caractéristique additionnelle de l’invention, le système d’alimentation comprend un organe de contrôle, par exemple de type vanne, disposé entre le réservoir d’hydrogène liquide et l’évaporateur. L’organe de contrôle sert notamment à isoler le réservoir d’hydrogène liquide du système d’alimentation en hydrogène de la pile à combustible lorsque le véhicule est en stationnement, avant son démarrage. According to an additional characteristic of the invention, the supply system comprises a control member, for example of the valve type, arranged between the liquid hydrogen tank and the evaporator. The control unit serves in particular to isolate the liquid hydrogen tank from the hydrogen supply system of the fuel cell when the vehicle is parked, before it is started.
Selon une autre caractéristique de l’invention, le conduit de fluide caloporteur fait partie d’un système de régulation thermique comprenant un organe de régulation, cet organe de régulation étant destiné à orienter le passage du fluide caloporteur entre un échangeur de chaleur et une dérivation. According to another characteristic of the invention, the heat transfer fluid conduit is part of a thermal regulation system comprising a regulating member, this regulating member being intended to orient the passage of the heat transfer fluid between a heat exchanger and a bypass .
Ce système de régulation thermique permet d’une part de réguler la température du fluide caloporteur, et d’autre part de réguler la température de la pile à combustible. À cet effet le système de régulation thermique comprend l’organe de régulation, par exemple un thermostat, en fonction duquel le fluide caloporteur sera orienté soit vers l’échangeur de chaleur, soit vers une dérivation évitant le passage du fluide caloporteur à travers cet échangeur de chaleur qui peut notamment être un radiateur. On comprend ainsi que l’organe de régulation permet de bypasser, c’est-à-dire de contourner l’échangeur de chaleur, le fluide caloporteur n’échangeant pas de calories au sein de cet échangeur de chaleur et pouvant améliorer l’efficacité de l’évaporation d’hydrogène dans l’enceinte. Selon une caractéristique de l’invention, le système de régulation thermique comprend une première branche apte à réguler la température de la pile à combustible. This thermal regulation system makes it possible on the one hand to regulate the temperature of the heat transfer fluid, and on the other hand to regulate the temperature of the fuel cell. To this end, the thermal regulation system comprises the regulating member, for example a thermostat, according to which the heat transfer fluid will be directed either towards the heat exchanger, or towards a bypass preventing the passage of the heat transfer fluid through this exchanger. heat which may in particular be a radiator. It is thus understood that the regulating member makes it possible to bypass, that is to say to bypass the heat exchanger, the heat transfer fluid not exchanging calories within this heat exchanger and being able to improve the efficiency. hydrogen evaporation in the containment. According to one characteristic of the invention, the thermal regulation system comprises a first branch able to regulate the temperature of the fuel cell.
Cette première branche participe à l’augmentation de la température du fluide caloporteur jusqu’à une température optimale pour le fonctionnement de la pile à combustible, qui est proche de 50 à 70 °C. This first branch participates in increasing the temperature of the heat transfer fluid to an optimum temperature for the operation of the fuel cell, which is close to 50 to 70°C.
Lorsque la température de la pile à combustible est inférieure à la température optimale de fonctionnement de la pile, l’organe de régulation laisse fermer le passage du fluide caloporteur au travers de l’échangeur de chaleur, à savoir ici un radiateur de refroidissement. En contournant ainsi le radiateur de refroidissement, le fluide caloporteur circulant dans la première branche n’est pas refroidi, provoquant avantageusement une montée en température de la pile à combustible. When the temperature of the fuel cell is lower than the optimum operating temperature of the cell, the regulating member closes the passage of the heat transfer fluid through the heat exchanger, namely here a cooling radiator. By thus bypassing the cooling radiator, the heat transfer fluid circulating in the first branch is not cooled, advantageously causing a rise in temperature of the fuel cell.
Selon une autre caractéristique de l’invention, le système de régulation thermique comprend une deuxième branche apte à réguler la température au sein de l’évaporateur. According to another characteristic of the invention, the thermal regulation system comprises a second branch able to regulate the temperature within the evaporator.
Selon une autre caractéristique de l’invention, le système de régulation thermique comprend une vanne réglable, notamment de type vanne à trois voies, interposée entre la première branche et la deuxième branche et qui est configurée pour réguler le débit de fluide caloporteur au sein de la deuxième branche. According to another characteristic of the invention, the thermal regulation system comprises an adjustable valve, in particular of the three-way valve type, interposed between the first branch and the second branch and which is configured to regulate the flow rate of heat transfer fluid within the second branch.
La chaleur nécessaire à faire évaporer l’hydrogène liquide dépend de la consommation de l’hydrogène, et de la température du fluide caloporteur circulant dans la deuxième branche, notamment à travers l’évaporateur. La vanne réglable située à la jonction de la première branche et de la deuxième branche est apte à réguler le débit du fluide caloporteur afin d’amener la température de l’hydrogène en l’état gazeux à la sortie de l’évaporateur sensiblement à la température de la pile à combustible. The heat required to evaporate the liquid hydrogen depends on the consumption of the hydrogen, and the temperature of the heat transfer fluid circulating in the second branch, in particular through the evaporator. The adjustable valve located at the junction of the first branch and the second branch is capable of regulating the flow rate of the heat transfer fluid in order to bring the temperature of the hydrogen in the gaseous state at the outlet of the evaporator substantially to the fuel cell temperature.
L’invention concerne également un procédé d’alimentation en hydrogène d’une pile à combustible, comprenant une étape d’acheminement de l’hydrogène à l’évaporateur, une étape d’évaporation et de montée en pression de l’hydrogène et une étape de transmission de l’hydrogène à la pile à combustible. The invention also relates to a process for supplying hydrogen to a fuel cell, comprising a step for conveying the hydrogen to the evaporator, a step for evaporating and hydrogen pressure and a step for transmitting the hydrogen to the fuel cell.
L’étape d’acheminement de l’hydrogène correspond au déplacement de l’hydrogène depuis le réservoir dans lequel il est stocké sous forme liquide jusqu’au sein de l’évaporateur. L’étape d’évaporation de l’hydrogène intervient au sein de cet évaporateur, où il passe d’un état liquide à un état gazeux, ce qui engendre une augmentation de sa pression. Cette étape d’évaporation nécessite le réchauffement de l’hydrogène, qui est notamment réalisé par le biais du fluide caloporteur. L’étape de transmission de l’hydrogène à la pile à combustible correspond à l’acheminement de l’hydrogène sous forme gazeuse depuis l’évaporateur jusqu’à la pile à combustible. Il traverse à cet effet la turbine, qui permet la récupération d’énergie mécanique de pression. The hydrogen delivery step corresponds to the movement of hydrogen from the tank in which it is stored in liquid form to within the evaporator. The hydrogen evaporation step takes place within this evaporator, where it changes from a liquid state to a gaseous state, which generates an increase in its pressure. This evaporation step requires the heating of the hydrogen, which is carried out in particular by means of the heat transfer fluid. The stage of transmission of hydrogen to the fuel cell corresponds to the transport of hydrogen in gaseous form from the evaporator to the fuel cell. For this purpose, it passes through the turbine, which allows the recovery of mechanical pressure energy.
Selon une caractéristique de l’invention, le procédé d’alimentation comprend une sous-étape de contrôle de pression, cette sous-étape de contrôle étant au moins en partie assurée par l’au moins une vanne. According to one characteristic of the invention, the supply method comprises a pressure control sub-step, this control sub-step being at least partly ensured by the at least one valve.
Cette sous-étape de contrôle de pression intervient lors de l’étape de transmission de l’hydrogène sous forme gazeuse à la pile à combustible. L’ouverture de la vanne permet de libérer l’hydrogène gazeux lorsqu’il est à une pression convenable pour l’alimentation de la pile à combustible, et la fermeture de cette vanne permet de faire monter la pression de l’hydrogène gazeux au sein de l’enceinte avant de permettre son évacuation vers la pile à combustible. This pressure control sub-stage occurs during the stage of transmission of hydrogen in gaseous form to the fuel cell. Opening the valve allows hydrogen gas to be released when it is at a suitable pressure for supplying the fuel cell, and closing this valve allows the pressure of the hydrogen gas to rise within of the containment before allowing it to be evacuated to the fuel cell.
L’invention concerne enfin un véhicule électrique étant équipé d’un système d’alimentation tel que décrit précédemment, et/ou étant alimenté en hydrogène selon le procédé d’alimentation tel que décrit précédemment.The invention finally relates to an electric vehicle being equipped with a supply system as described previously, and/or being supplied with hydrogen according to the supply method as described previously.
D’autres caractéristiques, détails et avantages de l’invention ressortiront plus clairement à la lecture de la description qui suit d’une part, et d’exemples de réalisation donnés à titre indicatif et non limitatif en référence aux dessins annexés d’autre part, sur lesquels : Other characteristics, details and advantages of the invention will emerge more clearly on reading the description which follows on the one hand, and exemplary embodiments given by way of indication and not limitation with reference to the appended drawings on the other hand. , on which ones :
[Fig. i] illustre, schématiquement, un système de pile à combustible, comprenant un système d’alimentation de cette pile à combustible en hydrogène selon l’invention ; [Fig. i] schematically illustrates a fuel cell system, comprising a system for supplying this fuel cell by hydrogen according to the invention;
[Fig. 2] représente une vue de coupe d’un réceptacle au sein duquel circulent un fluide caloporteur et de l’hydrogène ; [Fig. 2] shows a cross-sectional view of a receptacle within which a heat transfer fluid and hydrogen circulate;
[Fig. 3] est une représentation schématique du réceptacle de la figure 2 selon une vue de dessus, présentant la répartition entre hydrogène sous forme liquide et hydrogène sous forme gazeuse ; [Fig. 3] is a schematic representation of the receptacle of FIG. 2 according to a top view, showing the distribution between hydrogen in liquid form and hydrogen in gaseous form;
[Fig. 4] est une autre représentation schématique du réceptacle de la figure 2 selon une vue de dessus, la répartition entre hydrogène sous forme liquide et hydrogène sous forme gazeuse étant différente de celle de la figure 3 ; [Fig. 4] is another schematic representation of the receptacle of FIG. 2 according to a top view, the distribution between hydrogen in liquid form and hydrogen in gaseous form being different from that of FIG. 3;
[Fig. 5] illustre, schématiquement, une variante du système de pile à combustible de la figure 1, comprenant un système d’alimentation de cette pile à combustible en hydrogène selon l’invention. [Fig. 5] schematically illustrates a variant of the fuel cell system of FIG. 1, comprising a system for supplying this fuel cell with hydrogen according to the invention.
Les caractéristiques, variantes et les différentes formes de réalisation de l’invention peuvent être associées les unes avec les autres, selon diverses combinaisons, dans la mesure où elles ne sont pas incompatibles ou exclusives les unes par rapport aux autres. On pourra notamment imaginer des variantes de l’invention ne comprenant qu’une sélection de caractéristiques décrites par la suite de manière isolée des autres caractéristiques décrites, si cette sélection de caractéristiques est suffisante pour conférer un avantage technique et/ou pour différencier l’invention par rapport à l’état de la technique antérieur. The features, variants and different embodiments of the invention may be associated with each other, in various combinations, insofar as they are not incompatible or exclusive with respect to each other. In particular, variants of the invention may be imagined comprising only a selection of characteristics described below in isolation from the other characteristics described, if this selection of characteristics is sufficient to confer a technical advantage and/or to differentiate the invention. compared to the prior art.
Sur les figures, les éléments communs à plusieurs figures conservent la même référence. In the figures, the elements common to several figures retain the same reference.
Dans la description détaillée qui va suivre, le terme « fluide caloporteur » peut se rapporter à tout fluide ou liquide caloporteur, dès lors que ce fluide ou liquide a pour effet de refroidir ou de chauffer un système de pile à combustible. In the detailed description that follows, the term “heat transfer fluid” can refer to any heat transfer fluid or liquid, provided that this fluid or liquid has the effect of cooling or heating a fuel cell system.
La figure 1 illustre ainsi, schématiquement, un système 16 de pile à combustible 1 comprenant un système d’alimentation en hydrogène 17 de cette pile à combustible 1 selon l’invention. La pile à combustible i permet d’alimenter un véhicule électrique en énergie électrique lorsqu’une batterie de ce véhicule est déchargée. La pile à combustible i fonctionne grâce à de l’hydrogène sous forme gazeuse, qui est selon l’invention obtenu à partir d’un hydrogène stocké sous forme liquide, pour des raisons d’encombrement notamment. L’hydrogène sous forme liquide est ici stocké dans le réservoir de stockage 2, qui est un réservoir adiabatique où l’hydrogène est à une température inférieure ou égale à - 253 °C, une telle température correspondant au point de condensation de l’hydrogène à pression atmosphérique, soit une température à laquelle il est sous forme liquide. FIG. 1 thus illustrates, schematically, a fuel cell 1 system 16 comprising a hydrogen supply system 17 for this fuel cell 1 according to the invention. The fuel cell i makes it possible to supply an electric vehicle with electrical energy when a battery of this vehicle is discharged. The fuel cell i operates using hydrogen in gaseous form, which according to the invention is obtained from hydrogen stored in liquid form, for reasons of space in particular. Hydrogen in liquid form is here stored in storage tank 2, which is an adiabatic tank where the hydrogen is at a temperature less than or equal to -253°C, such a temperature corresponding to the dew point of hydrogen at atmospheric pressure, i.e. a temperature at which it is in liquid form.
Le procédé d’alimentation de la pile à combustible 1 en hydrogène comprend une étape d’acheminement de cet hydrogène, au cours de laquelle l’hydrogène sous forme liquide est acheminé depuis son réservoir de stockage 2 jusqu’à un évaporateur 4. Il traverse à cet effet un organe de contrôle 6, par exemple de type vanne, qui permet de réguler le flux d’hydrogène. The process for supplying the fuel cell 1 with hydrogen comprises a step for conveying this hydrogen, during which the hydrogen in liquid form is conveyed from its storage tank 2 to an evaporator 4. It passes through for this purpose a control member 6, for example of the valve type, which makes it possible to regulate the flow of hydrogen.
L’hydrogène sous forme liquide pénètre dans l’évaporateur 4 par un tube 610, qui correspond à une alimentation en hydrogène sous forme liquide 61. The hydrogen in liquid form enters the evaporator 4 through a tube 610, which corresponds to a supply of hydrogen in liquid form 61.
Le procédé d’alimentation de la pile à combustible 1 se poursuit par une étape d’évaporation, durant laquelle l’hydrogène sous forme liquide est transformé en hydrogène sous forme gazeuse sous l’effet d’un phénomène d’évaporation, qui résulte d’une augmentation de sa température et entraîne une augmentation de la pression. Les moyens mis en œuvre pour réaliser cette étape d’évaporation seront plus particulièrement décrits ci-après. L’hydrogène quitte ensuite l’évaporateur 4 par le biais d’un canal 620, qui correspond à une évacuation d'hydrogène sous forme gazeuse 62. The process for supplying the fuel cell 1 continues with an evaporation step, during which the hydrogen in liquid form is transformed into hydrogen in gaseous form under the effect of an evaporation phenomenon, which results from an increase in its temperature and leads to an increase in pressure. The means implemented to carry out this evaporation step will be more particularly described below. The hydrogen then leaves the evaporator 4 through a channel 620, which corresponds to an evacuation of hydrogen in gaseous form 62.
Le procédé d’alimentation de la pile à combustible 1 comprend enfin une étape d’alimentation de cette pile à combustible 1. À cet effet, en sortie de l’évaporateur 4 l’hydrogène traverse une première vanne 5a, qui constitue un moyen de contrôle de pression. La première vanne 5a peut être pilotée et configurée pour ne s’ouvrir que lorsque la pression de l’hydrogène gazeux atteint une valeur seuil, qui est ici inférieure à un point critique de 13 bars, par exemple une valeur comprise entre 10 et 12 bars. En dessous de cette valeur seuil, la première vanne 5a reste fermée et ainsi le phénomène d’évaporation se poursuit au sein de l’évaporateur 4, jusqu’à ce que l’hydrogène ait atteint la pression requise. On comprend donc que la première vanne 5a intervient dans une sous-étape du procédé d’alimentation de la pile à combustible 1 en hydrogène, à savoir une sous-étape de contrôle de pression. Pour assurer une alimentation précise à une pression prédéterminée de l’hydrogène dans la pile à combustible 1, le système d’alimentation en hydrogène 17 de la pile à combustible 1 peut également comprendre un réservoir tampon 7, qui participe également à la sous-étape de contrôle de la pression. Le réservoir tampon 7 est ainsi disposé en aval de cette première vanne 5a selon le sens d’écoulement de l’hydrogène vers la pile à combustible 1. Lorsque l’hydrogène est à la pression requise, la première vanne 5a s’ouvre et l’hydrogène entre dans ce réservoir tampon 7. The process for supplying the fuel cell 1 finally comprises a step for supplying this fuel cell 1. For this purpose, at the outlet of the evaporator 4 the hydrogen passes through a first valve 5a, which constitutes a means of pressure control. The first valve 5a can be controlled and configured to open only when the pressure of the hydrogen gas reaches a threshold value, which is here below a critical point of 13 bars, for example a value between 10 and 12 bars . Below this threshold value, the first valve 5a remains closed and thus the evaporation phenomenon continues within the evaporator 4, until the hydrogen has reached the required pressure. It is therefore understood that the first valve 5a intervenes in a sub-step of the process for supplying the fuel cell 1 with hydrogen, namely a pressure control sub-step. To ensure a precise supply at a predetermined pressure of hydrogen in the fuel cell 1, the hydrogen supply system 17 of the fuel cell 1 can also comprise a buffer tank 7, which also participates in the sub-step pressure control. The buffer tank 7 is thus arranged downstream of this first valve 5a according to the direction of flow of the hydrogen towards the fuel cell 1. When the hydrogen is at the required pressure, the first valve 5a opens and the hydrogen enters this buffer tank 7.
Une deuxième vanne 5b, disposée en aval du réservoir tampon 7 selon le sens d’écoulement de l’hydrogène vers la pile à combustible 1, permet un contrôle de la pression en amont de la turbine et du débit d’hydrogène en l’état gazeux dans la turbine. Cette turbine 3 est disposée entre le canal 620 d’évacuation d'hydrogène sous forme gazeuse 62 et la pile à combustible 1, et plus précisément entre la deuxième vanne 5b et la pile à combustible 1. La turbine a pour rôle de détendre l’hydrogène qui est sous forme gazeuse. Par conséquent, sa pression diminue, de façon à atteindre une pression optimale pour le fonctionnement de la pile à combustible 1. L’énergie mécanique dégagée par une telle diminution de pression est récupérée par la turbine 3. Cette énergie mécanique peut être employée de différentes façons. L’énergie mécanique peut ainsi servir au fonctionnement d’un compresseur d’air 10, capable de récupérer de l’air ambiant afin d’alimenter la pile à combustible 1 en oxygène. Alternativement, si l’énergie mécanique générée est supérieure à l’énergie mécanique nécessaire au fonctionnement du compresseur d’air 10, elle peut être utilisée pour faire fonctionner un générateur électrique 20 qui fournit l’énergie électrique au véhicule. Après son passage dans la turbine 3 et sa détente, l’hydrogène sous forme gazeuse peut être acheminé jusqu’à la pile à combustible 1 par une conduite 21 pour y produire de l’énergie électrique. L’évaporateur 4 est représenté schématiquement sur les figures 2 à 4. La figure 2 est une représentation d’une coupe de cet évaporateur 4 selon une vue de face, tandis que les figures 3 et 4 sont des vues de dessus qui représentent des répartitions différentes entre hydrogène sous forme liquide et hydrogène sous forme gazeuse. A second valve 5b, arranged downstream of the buffer tank 7 according to the direction of flow of the hydrogen towards the fuel cell 1, allows control of the pressure upstream of the turbine and of the flow of hydrogen in the state gas in the turbine. This turbine 3 is arranged between the channel 620 for discharging hydrogen in gaseous form 62 and the fuel cell 1, and more precisely between the second valve 5b and the fuel cell 1. The turbine has the role of expanding the hydrogen which is in gaseous form. Consequently, its pressure decreases, so as to reach an optimum pressure for the operation of the fuel cell 1. The mechanical energy released by such a decrease in pressure is recovered by the turbine 3. This mechanical energy can be used in different ways. manners. The mechanical energy can thus be used to operate an air compressor 10, capable of recovering ambient air in order to supply the fuel cell 1 with oxygen. Alternatively, if the mechanical energy generated is greater than the mechanical energy needed to operate the air compressor 10, it can be used to operate an electric generator 20 which provides electric power to the vehicle. After passing through turbine 3 and expanding, the hydrogen in gaseous form can be routed to fuel cell 1 through a pipe 21 to produce electrical energy there. The evaporator 4 is represented schematically in FIGS. 2 to 4. FIG. 2 is a representation of a section of this evaporator 4 according to a front view, while FIGS. 3 and 4 are top views which represent distributions different between hydrogen in liquid form and hydrogen in gaseous form.
L’évaporateur 4 comprend un réceptacle 40 délimité par une enceinte 41. Cette enceinte 41 se compose de deux parois frontales 46 et d’une paroi latérale périphérique 47, qui est disposée entre les parois frontales 46 et les relie. Ces parois frontales 46 sont ici parallèles et opposées l’une à l’autre. Si l’évaporateur 4 présente une forme cylindrique, comme c’est le cas sur les figures 3 et 4, la paroi latérale périphérique 47 s’entend d’une face latérale ou surface cylindrique de cette forme cylindrique. On peut également envisager que l’évaporateur 4 prenne la forme d’un pavé droit, auquel cas la paroi latérale périphérique 47 correspondrait à la continuité de quatre parois latérales contigües de ce pavé droit. The evaporator 4 comprises a receptacle 40 delimited by an enclosure 41. This enclosure 41 consists of two front walls 46 and a peripheral side wall 47, which is arranged between the front walls 46 and connects them. These front walls 46 are here parallel and opposite to each other. If the evaporator 4 has a cylindrical shape, as is the case in Figures 3 and 4, the peripheral side wall 47 means a side face or cylindrical surface of this cylindrical shape. It is also possible to envisage the evaporator 4 taking the form of a straight block, in which case the peripheral side wall 47 would correspond to the continuity of four contiguous side walls of this straight block.
L’évaporateur 4 est équipé d’une alimentation en hydrogène sous forme liquide 61 et d’une évacuation d'hydrogène sous forme gazeuse 62. Cette alimentation en hydrogène sous forme liquide 61 et cette évacuation d'hydrogène sous forme gazeuse 62 sont raccordées sur la paroi latérale périphérique 47, par le biais respectivement d’un tube 610 et d’un canal 620. L’hydrogène sous forme liquide est ainsi acheminé jusqu’à l’évaporateur 4 par le tube 610 d’alimentation en hydrogène sous forme liquide, et il quitte cet évaporateur 4 sous forme gazeuse par le canal 620 d’évacuation d'hydrogène sous forme gazeuse. The evaporator 4 is equipped with a supply of hydrogen in liquid form 61 and an evacuation of hydrogen in gaseous form 62. This supply of hydrogen in liquid form 61 and this evacuation of hydrogen in gaseous form 62 are connected to the peripheral side wall 47, via a tube 610 and a channel 620 respectively. The hydrogen in liquid form is thus conveyed to the evaporator 4 by the tube 610 for supplying hydrogen in liquid form , and it leaves this evaporator 4 in gaseous form through the channel 620 for discharging hydrogen in gaseous form.
Selon l’invention, le réceptacle 40 de l’évaporateur 4 et son enceinte 41 sont traversés de part en part par un conduit de fluide caloporteur 45, au sein duquel ce fluide caloporteur circule. Ce conduit de fluide caloporteur 45 est raccordé sur chacune des parois frontales 46, et s’étend au sein de l’enceinte 41 selon la direction d’un axe médian M. Cet axe médian M peut par exemple correspondre, si le réceptacle 40 a une forme de cylindre, à l’axe de révolution de ce cylindre. Le conduit de fluide caloporteur 45 est associé à un élément résistif de chauffage 44, qui dans l’exemple illustré, consiste en un fil résistif logé au sein du conduit de fluide refroidissement. Cet élément résistif de chauffage 44 participe, en association avec le fluide caloporteur, à réchauffer l’hydrogène afin de l’évaporer et ainsi de le faire passer de sa forme liquide à sa forme gazeuse, dans laquelle il est apte à alimenter la pile à combustible 1.According to the invention, the receptacle 40 of the evaporator 4 and its enclosure 41 are crossed right through by a heat transfer fluid conduit 45, within which this heat transfer fluid circulates. This heat transfer fluid duct 45 is connected to each of the front walls 46, and extends within the enclosure 41 in the direction of a median axis M. This median axis M may for example correspond, if the receptacle 40 has a cylinder shape, at the axis of revolution of this cylinder. The heat transfer fluid conduit 45 is associated with a resistive heating element 44, which in the example shown, consists of a resistive wire housed within the cooling fluid conduit. This resistive heating element 44 participates, in association with the heat transfer fluid, in heating the hydrogen in order to evaporate it and thus to make it pass from its liquid form to its gaseous form, in which it is able to supply the fuel cell. fuel 1.
Au sein de l’enceinte 41 est disposé un matériau poreux, qui est donc également traversé par le conduit de fluide caloporteur 45. La configuration de ce matériau poreux permet d’augmenter les surfaces d’échange au sein de l’évaporateur 4. Ce matériau poreux est apte à être traversé par l’hydrogène selon un phénomène de capillarité. L’hydrogène arrive en effet dans l’évaporateur 4 par le tube 610 d’alimentation en hydrogène sous forme liquide, et cet hydrogène liquide est aspiré par capillarité au sein de l’évaporateur 4. La capillarité est possible du fait de la coexistence d’hydrogène sous forme liquide et sous forme gazeuse. Lorsqu’il n’y a plus soit d’hydrogène sous forme liquide, soit d’hydrogène sous forme gazeuse, le phénomène de capillarité ne plus intervenir et l’arrivée d’hydrogène liquide au sein de l’évaporateur 4 est donc empêchée. Le système d’alimentation en hydrogène 17 est donc auto-régulé lors de l’étape d’acheminement de cet hydrogène vers l’évaporateur 4. Within the enclosure 41 is placed a porous material, which is therefore also crossed by the heat transfer fluid conduit 45. The configuration of this porous material makes it possible to increase the exchange surfaces within the evaporator 4. This porous material is able to be crossed by hydrogen according to a phenomenon of capillarity. The hydrogen in fact arrives in the evaporator 4 through the hydrogen supply tube 610 in liquid form, and this liquid hydrogen is sucked up by capillarity within the evaporator 4. Capillarity is possible due to the coexistence of hydrogen in liquid form and in gaseous form. When there is no longer either hydrogen in liquid form or hydrogen in gaseous form, the capillarity phenomenon no longer occurs and the arrival of liquid hydrogen within the evaporator 4 is therefore prevented. The hydrogen supply system 17 is therefore self-regulated during the step of conveying this hydrogen to the evaporator 4.
Au sein du matériau poreux, il est possible de délimiter deux portions, à savoir une première portion 42 correspondant à la portion du matériau poreux où l’hydrogène circule sous sa forme liquide, et une deuxième portion 43 correspondant à la portion du matériau poreux où l’hydrogène circule sous sa forme gazeuse. Tel que cela est visible sur les figures, il n’existe pas de séparation physique entre la première portion 42 et la deuxième portion 43, les traits pointillés étant représentés ici pour illustrer cette séparation abstraite. Les volumes des deux portions sont variables, et dépendent respectivement de la proportion en hydrogène liquide et en hydrogène gazeux dans le réceptacle 40 de l’évaporateur 4. Les figures 3 et 4 illustrent ces différences de proportion, la deuxième portion 43 correspondant à l’hydrogène gazeux étant plus importante sur la figure 4 que sur la figure 3. Cette proportion en hydrogène liquide et en hydrogène gazeux est influencée par l’action du fluide caloporteur, qui circule au sein du conduit de fluide caloporteur 45, et de l’élément résistif de chauffage 44 qui est également disposé dans le conduit de fluide caloporteur 45. En effet, le fluide caloporteur et l’élément résistif de chauffage 44 réchauffant l’hydrogène, ils influent sur la proportion d’hydrogène liquide et d’hydrogène gazeux puisqu’un tel réchauffement résulte en l’évaporation de cet hydrogène. Par conséquent, la délimitation entre la première portion 42 et la deuxième portion 43 est évolutive en fonction du différentiel de température entre le fluide caloporteur et l’hydrogène liquide. Within the porous material, it is possible to delimit two portions, namely a first portion 42 corresponding to the portion of the porous material where the hydrogen circulates in its liquid form, and a second portion 43 corresponding to the portion of the porous material where hydrogen circulates in its gaseous form. As can be seen in the figures, there is no physical separation between the first portion 42 and the second portion 43, the dotted lines being represented here to illustrate this abstract separation. The volumes of the two portions are variable, and depend respectively on the proportion of liquid hydrogen and gaseous hydrogen in the receptacle 40 of the evaporator 4. FIGS. 3 and 4 illustrate these differences in proportion, the second portion 43 corresponding to the hydrogen gas being more important in figure 4 than in figure 3. This proportion of liquid hydrogen and gaseous hydrogen is influenced by the action of the heat transfer fluid, which circulates within the heat transfer fluid conduit 45, and of the resistive heating element 44 which is also placed in the heat transfer fluid conduit 45 Indeed, the heat transfer fluid and the resistive heating element 44 heating the hydrogen, they influence the proportion of liquid hydrogen and gaseous hydrogen since such heating results in the evaporation of this hydrogen. Consequently, the delimitation between the first portion 42 and the second portion 43 changes according to the temperature differential between the heat transfer fluid and the liquid hydrogen.
L’élément résistif de chauffage 44 est apte à réchauffer l’hydrogène de différentes façons. Il peut ainsi le réchauffer de façon indirecte, en réchauffant le fluide caloporteur qui à son tour réchauffe l’hydrogène, ou de façon directe, puisqu’il réchauffe le matériau poreux où circule l’hydrogène qui se trouve à son voisinage. The resistive heating element 44 is able to heat the hydrogen in different ways. It can thus heat it indirectly, by heating the heat transfer fluid which in turn heats the hydrogen, or directly, since it heats the porous material in which the hydrogen circulates in its vicinity.
L’élément résistif de chauffage a notamment pour fonction de réchauffer le fluide caloporteur au sein du conduit, notamment au démarrage du véhicule, afin de s’assurer que le fluide caloporteur, qui est au voisinage de l’hydrogène sous forme liquide à -253°C, ne gèle pas. L’élément résistif de chauffage 44 est de ce fait tout particulièrement utilisé lors de la mise en œuvre du système 16 de pile à combustible 1. Le fluide caloporteur peut ainsi se liquéfier, passant de l’état solide dans lequel il est gelé lors de l’arrêt du véhicule à l’état liquide dans lequel il peut circuler. L’élément résistif de chauffage peut néanmoins être utilisé lorsque le fluide caloporteur est liquéfié, accélérant ainsi l’évaporation de l’hydrogène. The resistive heating element has the particular function of heating the heat transfer fluid within the conduit, in particular when the vehicle is started, in order to ensure that the heat transfer fluid, which is in the vicinity of hydrogen in liquid form at -253 °C, does not freeze. The resistive heating element 44 is therefore very particularly used during the implementation of the fuel cell system 16 1. The heat transfer fluid can thus liquefy, passing from the solid state in which it is frozen during stopping the vehicle in the liquid state in which it can circulate. The resistive heating element can nevertheless be used when the heat transfer fluid is liquefied, thus accelerating the evaporation of the hydrogen.
On comprend que puisque le conduit de fluide caloporteur 45 est l’élément de l’évaporateur 4 à partir duquel la chaleur diffuse dans cet évaporateur 4, plus on s’éloigne du conduit de fluide caloporteur 45 et plus la proportion en hydrogène liquide augmente. Il en résulte que la première portion 42 dans laquelle circule l’hydrogène sous forme liquide est plus éloignée de ce conduit de fluide caloporteur 45 que la deuxième portion 43 dans laquelle circule l’hydrogène sous forme gazeuse. Ce phénomène est illustré aux figures 3 et 4, dans lesquelles le conduit de fluide caloporteur 45, la première portion 42 et la deuxième portion 43 sont représentées sous forme de disques concentriques au sein de l’enceinte 41 de l’évaporateur 4. It is understood that since the heat transfer fluid conduit 45 is the element of the evaporator 4 from which the heat diffuses into this evaporator 4, the further one moves away from the heat transfer fluid conduit 45, the more the proportion of liquid hydrogen increases. As a result, the first portion 42 in which the hydrogen circulates in liquid form is farther from this heat transfer fluid conduit 45 than the second portion 43 in which the hydrogen circulates in gaseous form. This phenomenon is illustrated in Figures 3 and 4, in which the heat transfer fluid conduit 45, the first portion 42 and the second portion 43 are represented in the form of concentric discs within the enclosure 41 of the evaporator 4.
Ces figures 3 et 4 illustrent également le fait que le conduit de fluide caloporteur 45 est décentré par rapport à l’axe médian M traversant les parois frontales 46, ces parois frontales étant visibles en figure 2. Ainsi, une distance la plus courte Di mesurée entre le conduit de fluide caloporteur 45 et l’évacuation d’hydrogène sous forme gazeuse 62 est inférieure à une distance la plus courte D2 mesurée entre le conduit de fluide caloporteur 45 et l’alimentation en hydrogène sous forme liquide 61. Cette différence entre la distance de l’évacuation d'hydrogène sous forme gazeuse 62 au conduit de fluide caloporteur 45 et la distance de l’alimentation en hydrogène sous forme liquide 61 au conduit de fluide caloporteur 45 permet de s’assurer que l’hydrogène sortant par l’évacuation d'hydrogène sous forme gazeuse 62 est bien gazeux. L’hydrogène sous forme gazeuse est en effet formé plus rapidement au voisinage de la paroi latérale périphérique 47 porteuse de l’évacuation d'hydrogène sous forme gazeuse 62, et donc de proche en proche l’hydrogène liquide arrivant à proximité de cette paroi latérale périphérique 47 porteuse de l’évacuation d'hydrogène sous forme gazeuse 62 est vaporisé.These Figures 3 and 4 also illustrate the fact that the heat transfer fluid duct 45 is off-center with respect to the central axis M passing through the front walls 46, these front walls being visible in Figure 2. Thus, a shortest distance Di measured between the heat transfer fluid conduit 45 and the hydrogen gas discharge 62 is less than a shortest distance D2 measured between the heat transfer fluid conduit 45 and the hydrogen supply in liquid form 61. This difference between the distance from the evacuation of hydrogen in gaseous form 62 to the heat transfer fluid pipe 45 and the distance from the supply of hydrogen in liquid form 61 to the heat transfer fluid pipe 45 makes it possible to ensure that the hydrogen leaving through the evacuation of hydrogen in gaseous form 62 is indeed gaseous. The hydrogen in gaseous form is in fact formed more rapidly in the vicinity of the peripheral side wall 47 carrying the evacuation of hydrogen in gaseous form 62, and therefore gradually the liquid hydrogen arriving near this side wall device 47 carrying the evacuation of hydrogen in gaseous form 62 is vaporized.
Le système d’alimentation en hydrogène 17 de la pile à combustible 1 est ainsi formé, notamment, de l’évaporateur 4, de la turbine 3 et de la pile à combustible 1. Le système 16 de pile à combustible 1 comprend, en parallèle de ce système d’alimentation en hydrogène 17, un système de régulation thermique 18 visible sur la figure 1. Ce système de régulation thermique 18 permet de réguler la température à la fois au sein de l’évaporateur 4, en amenant le fluide caloporteur à une température appropriée, et de la pile à combustible 1. The hydrogen supply system 17 of the fuel cell 1 is thus formed, in particular, of the evaporator 4, of the turbine 3 and of the fuel cell 1. The system 16 of fuel cell 1 comprises, in parallel of this hydrogen supply system 17, a thermal regulation system 18 visible in FIG. 1. This thermal regulation system 18 makes it possible to regulate the temperature both within the evaporator 4, by bringing the heat transfer fluid to an appropriate temperature, and the fuel cell 1.
Un premier exemple de réalisation, simplifié, du système de régulation thermique 18 est illustré sur la figure 1. A first simplified embodiment of the thermal regulation system 18 is illustrated in FIG. 1.
La régulation de la température de fluide caloporteur est nécessaire, notamment pour participer à éviter le gel du fluide caloporteur au sein du conduit de fluide caloporteur 45 tel qu’expliqué précédemment. Le conduit de fluide caloporteur 45 est ainsi intégré dans le système de régulation thermique 18, qui fait par ailleurs intervenir un organe de régulation 34. Cet organe de régulation 34, par exemple un thermostat, a pour fonction d’orienter le fluide caloporteur selon deux voies différentes selon que sa température est suffisante ou non. Regulating the temperature of the heat transfer fluid is necessary, in particular to participate in preventing freezing of the heat transfer fluid within the heat transfer fluid conduit 45 as explained above. The conduit of heat transfer fluid 45 is thus integrated into the thermal regulation system 18, which also involves a regulating member 34. This regulating member 34, for example a thermostat, has the function of directing the heat transfer fluid along two different paths depending on whether its temperature is sufficient or not.
Si la température du fluide caloporteur est trop élevée, c’est-à-dire au-delà de la température optimale de fonctionnement de la pile à combustible 1, celui- ci est orienté par l’organe de régulation 34 vers un échangeur de chaleur 30, qui peut notamment être un radiateur. Lorsque le fluide caloporteur passe dans l’échangeur de chaleur 30 il cède des calories, qui peuvent par exemple être utilisées pour participer au chauffage de l’habitacle du véhicule. Le fluide caloporteur perdant des calories, il est refroidi. À l’inverse, lorsque la température du fluide caloporteur n’est pas suffisamment importante pour lui permettre de céder des calories tout en assurant la fonction de vaporisation d’hydrogène, l’organe de régulation 34 oriente le fluide caloporteur vers une dérivation ou bypass 35. Cette dérivation 35 permet au fluide caloporteur de contourner l’échangeur de chaleur 30. If the temperature of the heat transfer fluid is too high, that is to say beyond the optimum operating temperature of the fuel cell 1, the latter is directed by the regulating member 34 towards a heat exchanger 30, which may in particular be a radiator. When the heat transfer fluid passes through the heat exchanger 30, it releases calories, which can for example be used to participate in the heating of the passenger compartment of the vehicle. The heat transfer fluid losing calories, it is cooled. Conversely, when the temperature of the heat transfer fluid is not high enough to allow it to release calories while performing the hydrogen vaporization function, the regulating member 34 directs the heat transfer fluid towards a bypass or bypass. 35. This bypass 35 allows the heat transfer fluid to bypass the heat exchanger 30.
Le système de régulation thermique 18 permet, par le biais de l’organe de régulation 34,=de réguler à la fois la température du fluide caloporteur qui passe dans la pile à combustible 1 et celle du fluide caloporteur qui traverse l’évaporateur 4. Cela s’explique du fait de la configuration de ce système de régulation thermique 18, qui comprend plusieurs branches. Une première branche 36 est dédiée à la régulation de la température de la pile à combustible 1. Le fluide caloporteur circulant dans cette première branche 36 peut ainsi réguler la température de la pile à combustible 1, et notamment la réchauffer afin qu’elle atteigne sa température optimale, à savoir entre 50 et 70 °C environ. Une deuxième branche 38 participe à la régulation de la température au sein de l’évaporateur 4. Le fluide caloporteur circulant dans cette deuxième branche 38 est réchauffé par la pile à combustible de façon à pouvoir à son tour réchauffer l’hydrogène présent au sein de l’évaporateur 4, et donc de façon à pouvoir l’évaporer. On va maintenant décrire une variante du système de pile à combustible en référence à la figure 5, qui comporte comme précédemment, un évaporateur comprenant une enceinte au sein de laquelle est disposé un matériau poreux, l’enceinte étant traversée par un conduit de fluide caloporteur, et qui diffère notamment dans la conception du système de régulation thermique et le nombre et l’agencement des branches qui le constituent. Il convient de noter qu’une sélection des modifications présentes sur le système de pile à combustible de la variante illustrée sur la figure 5 et qui vont être décrites ci- après pourraient être mise en œuvre sans que l’on sorte pour autant de l’invention. The thermal regulation system 18 makes it possible, through the regulating member 34, to regulate both the temperature of the heat transfer fluid which passes through the fuel cell 1 and that of the heat transfer fluid which passes through the evaporator 4. This is explained by the configuration of this thermal regulation system 18, which comprises several branches. A first branch 36 is dedicated to regulating the temperature of the fuel cell 1. The heat transfer fluid circulating in this first branch 36 can thus regulate the temperature of the fuel cell 1, and in particular reheat it so that it reaches its optimum temperature, namely between 50 and 70 °C approximately. A second branch 38 participates in the regulation of the temperature within the evaporator 4. The heat transfer fluid circulating in this second branch 38 is heated by the fuel cell so as to be able in turn to heat the hydrogen present within the evaporator 4, and therefore so as to be able to evaporate it. A variant of the fuel cell system will now be described with reference to FIG. 5, which comprises, as before, an evaporator comprising an enclosure within which a porous material is placed, the enclosure being traversed by a heat transfer fluid conduit , and which differs in particular in the design of the thermal regulation system and the number and arrangement of the branches which constitute it. It should be noted that a selection of the modifications present on the fuel cell system of the variant illustrated in FIG. 5 and which will be described below could be implemented without departing from the invention.
Plus particulièrement, dans cette variante, la deuxième branche 38 est reliée à l’une de ses extrémités à la première branche par l’intermédiaire d’une vanne réglable 50, par exemple de type vanne à trois voies. Comme précédemment, l’organe de régulation 34, par exemple un thermostat, permet de réguler à la fois la température du fluide caloporteur qui passe dans la pile à combustible 1 et celle du fluide caloporteur qui traverse l’ évaporateur 4, tandis que la vanne réglable 50 permet de réguler le débit du caloporteur qui traverse l’évaporateur 4, en permettant de dériver une partie du débit, c’est-à-dire de o à 100% du débit, venant principalement de la pile à combustible 1, par la branche 38 raccordée à la vanne réglable 50, en direction de l’évaporateur 4. More particularly, in this variant, the second branch 38 is connected at one of its ends to the first branch via an adjustable valve 50, for example of the three-way valve type. As before, the regulating member 34, for example a thermostat, makes it possible to regulate both the temperature of the heat transfer fluid which passes through the fuel cell 1 and that of the heat transfer fluid which passes through the evaporator 4, while the valve adjustable 50 makes it possible to regulate the flow rate of the coolant which passes through the evaporator 4, by making it possible to derive part of the flow rate, that is to say from 0 to 100% of the flow rate, coming mainly from the fuel cell 1, by branch 38 connected to adjustable valve 50, in the direction of evaporator 4.
Selon la puissance à fournir par la pile à combustible 1, la quantité d’hydrogène varie, notamment augmente, de sorte que la vanne réglable 50 module la section d’ouverture de sa sortie en connexion fluidique avec la branche de dérivation traversant l’évaporateur, ce qui tend à augmenter le débit du fluide caloporteur dans l’évaporateur. En augmentant le débit du fluide caloporteur, l’échange thermique opéré au sein de l’évaporateur tend à augmenter la quantité d’hydrogène à l’état gazeux en sortie de l’évaporateur 4-Depending on the power to be supplied by the fuel cell 1, the quantity of hydrogen varies, in particular increases, so that the adjustable valve 50 modulates the opening section of its outlet in fluid connection with the bypass branch passing through the evaporator , which tends to increase the flow rate of the coolant in the evaporator. By increasing the flow rate of the heat transfer fluid, the heat exchange carried out within the evaporator tends to increase the quantity of hydrogen in the gaseous state at the outlet of the evaporator 4-
Le système de pile à combustible dans cette variante diffère aussi de ce qui précède en ce qu’il comporte une troisième branche 37 sur laquelle est disposé un refroidisseur 12 d’air comprimé circulant dans le circuit d’alimentation en air de la pile à combustible i. Le refroidisseur 12 permet de refroidir l’air comprimé pour augmenter la performance de la pile à combustible afin qu’elle délivre une puissance électrique augmentée sans incidence quant à sa taille. The fuel cell system in this variant also differs from the above in that it comprises a third branch 37 on which is arranged a cooler 12 of compressed air circulating in the circuit. fuel cell air supply i. The cooler 12 cools the compressed air to increase the performance of the fuel cell so that it delivers increased electrical power without affecting its size.
Le système de pile à combustible dans cette variante diffère aussi dans la présence d’une branche additionnelle dans laquelle est disposé un vase d’expansion 33 du circuit d’eau, qui peut notamment former un branche de contournement du radiateur 30. Le débit de fluide caloporteur circulant dans le vase d’expansion 33 est inférieur à celui du fluide circulant dans la deuxième branche 38. Cette branche additionnelle, ou branche de contournement, permet de limiter la montée en pression du circuit lorsque le liquide de refroidissement se dilate avec la température. Le vase d’expansion permet le remplissage du circuit en fluide caloporteur. Il permet également d’opérer le dégazage du circuit, notamment après une vidange. The fuel cell system in this variant also differs in the presence of an additional branch in which is placed an expansion tank 33 of the water circuit, which can in particular form a bypass branch of the radiator 30. The flow rate of heat transfer fluid circulating in the expansion vessel 33 is lower than that of the fluid circulating in the second branch 38. This additional branch, or bypass branch, makes it possible to limit the rise in pressure of the circuit when the coolant expands with the temperature. The expansion tank allows the circuit to be filled with heat transfer fluid. It also allows degassing of the circuit, in particular after emptying.
Par ailleurs, un système de pile à combustible selon l’invention peut comporter, tel qu’illustré sur la figure 5, au moins l’un de ces éléments additionnels parmi lesquels un filtre 11, un échangeur d’humidité 13 ou un circuit de recyclage de l’hydrogène. Furthermore, a fuel cell system according to the invention may comprise, as illustrated in FIG. 5, at least one of these additional elements, including a filter 11, a humidity exchanger 13 or a hydrogen recycling.
Le filtre 11 est disposé en amont du compresseur 10 du circuit d’alimentation en air pour éliminer les particules indésirables pour le fonctionnement optimal de la pile à combustible. The filter 11 is arranged upstream of the compressor 10 of the air supply circuit to eliminate unwanted particles for the optimal operation of the fuel cell.
L’échangeur d’humidité 13 air/air est destiné à transmettre l’humidité de l’air sortant de la pile à combustible à l’air entrant dans la pile à combustible. La réaction électrochimique de l’hydrogène avec l’oxygène produisant de l’eau, l’air sortant de la pile est ainsi appauvri en oxygène mais chargé en humidité. L’échangeur 13 permet un transfert de l’humidité de l’air sortant à l’air entrant, ce qui tend à améliorer le fonctionnement de la pile. The air/air humidity exchanger 13 is intended to transmit the humidity of the air leaving the fuel cell to the air entering the fuel cell. The electrochemical reaction of hydrogen with oxygen produces water, the air leaving the cell is thus depleted in oxygen but loaded with humidity. The exchanger 13 allows a transfer of humidity from the outgoing air to the incoming air, which tends to improve the operation of the cell.
Le circuit de recyclage de l’hydrogène sortant de la pile comporte une branche de retour dans laquelle est disposée un dispositif 8 d’aspiration de l’hydrogène qui peut être une tuyère ou une pompe. L’hydrogène circulant au travers de la pile à combustible 1 n’étant généralement pas consommée intégralement, le circuit de recyclage vise à réintroduire en entrée de la pile à combustible l’hydrogène restant tel qu’il est présent en sortie. The circuit for recycling the hydrogen leaving the cell comprises a return branch in which is placed a device 8 for sucking in the hydrogen which can be a nozzle or a pump. The hydrogen circulating through the fuel cell 1 generally not being consumed In its entirety, the recycling circuit aims to reintroduce the remaining hydrogen at the input of the fuel cell as it is present at the output.
La présente invention propose ainsi un système d’alimentation en hydrogène d’une pile à combustible faisant intervenir un processus d’évaporation autorégulé, qui permet de stocker de l’hydrogène sous forme liquide, et qui permet de compenser la consommation d’énergie survenue lors de l’étape de liquéfaction de l’hydrogène nécessaire à son stockage. Un tel système d’alimentation permet ainsi d’optimiser le rendement global du système de pile à combustible. La présente invention ne saurait toutefois se limiter aux moyens et configurations décrits et illustrés ici et elle s’étend également à tout moyen et toute configuration équivalents ainsi qu’à toute combinaison techniquement opérante de tels moyens. The present invention thus proposes a system for supplying hydrogen to a fuel cell involving a self-regulated evaporation process, which makes it possible to store hydrogen in liquid form, and which makes it possible to compensate for the energy consumption that has occurred during the stage of liquefaction of the hydrogen necessary for its storage. Such a power supply system thus makes it possible to optimize the overall efficiency of the fuel cell system. The present invention cannot however be limited to the means and configurations described and illustrated here and it also extends to any equivalent means and configuration as well as to any technically effective combination of such means.

Claims

REVENDICATIONS
1. Système d’alimentation en hydrogène (17) d’une pile à combustible (1) pour véhicule, comportant un évaporateur (4) équipé d’une alimentation en hydrogène sous forme liquide (61) et d’une évacuation d’hydrogène sous forme gazeuse (62), cet évaporateur (4) comprenant une enceinte (41) au sein de laquelle est disposé un matériau poreux, l’enceinte (41) étant traversée par un conduit de fluide caloporteur (45). 1. Hydrogen supply system (17) of a fuel cell (1) for a vehicle, comprising an evaporator (4) equipped with a supply of hydrogen in liquid form (61) and an evacuation of hydrogen in gaseous form (62), this evaporator (4) comprising an enclosure (41) within which is placed a porous material, the enclosure (41) being traversed by a heat transfer fluid conduit (45).
2. Système d’alimentation (17) selon la revendication précédente, dans lequel l’enceinte (41) comprend deux parois frontales (46) sur lesquelles est raccordé le conduit de fluide caloporteur (45), ainsi qu’une paroi latérale périphérique (47) reliant les parois frontales (46) et sur laquelle sont raccordées l’alimentation en hydrogène sous forme liquide (61) et l’évacuation d’hydrogène sous forme gazeuse (62). 2. Supply system (17) according to the preceding claim, in which the enclosure (41) comprises two front walls (46) to which the heat transfer fluid conduit (45) is connected, as well as a peripheral side wall ( 47) connecting the front walls (46) and on which are connected the supply of hydrogen in liquid form (61) and the evacuation of hydrogen in gaseous form (62).
3. Système d’alimentation (17) selon l’une quelconque des revendications précédentes, dans lequel le conduit de fluide caloporteur (45) comprend un élément électrique de chauffage (44). 3. Supply system (17) according to any one of the preceding claims, in which the heat transfer fluid conduit (45) comprises an electrical heating element (44).
4. Système d’alimentation (17) selon l’une quelconque des revendications précédentes en combinaison avec la revendication 2, dans lequel le conduit de fluide caloporteur (45) est décentré par rapport à un axe médian (M) de l’enceinte traversant les parois frontales (46), une distance la plus courte (Di) mesurée entre le conduit de fluide caloporteur (45) et l’évacuation d’hydrogène sous forme gazeuse (62) étant inférieure à une distance la plus courte (D2) mesurée entre le conduit de fluide caloporteur (45) et l’alimentation en hydrogène sous forme liquide (61). 4. Supply system (17) according to any one of the preceding claims in combination with claim 2, in which the heat transfer fluid conduit (45) is off-center with respect to a median axis (M) of the enclosure passing through the front walls (46), a shortest distance (Di) measured between the heat transfer fluid conduit (45) and the evacuation of hydrogen in gaseous form (62) being less than a shortest distance (D2) measured between the heat transfer fluid conduit (45) and the supply of hydrogen in liquid form (61).
5. Système d’alimentation (17) selon l’une quelconque des revendications précédentes comprenant une turbine (3), cette turbine (3) étant disposée entre le conduit d’évacuation en hydrogène sous forme gazeuse (62) et la pile à combustible (1). 5. Supply system (17) according to any one of the preceding claims comprising a turbine (3), this turbine (3) being arranged between the gaseous hydrogen evacuation pipe (62) and the fuel cell. (1).
6. Système d’alimentation (17) selon la revendication précédente comprenant au moins une vanne (5, 5b) apte à réguler une pression au sein du système d’alimentation (17) et étant disposée entre l’évaporateur (4) et la turbine (3). 6. Supply system (17) according to the preceding claim comprising at least one valve (5, 5b) able to regulate a pressure within of the supply system (17) and being arranged between the evaporator (4) and the turbine (3).
7. Système d’alimentation (17) selon l’une quelconque des revendications précédentes, dans lequel le conduit de fluide caloporteur (45) fait partie d’un système de régulation thermique (18) comprenant un organe de régulation (34), cet organe de régulation (34) étant destiné à orienter le passage du fluide caloporteur entre un échangeur de chaleur (30) et une dérivation (35). 7. Supply system (17) according to any one of the preceding claims, in which the heat transfer fluid conduit (45) is part of a thermal regulation system (18) comprising a regulation member (34), this regulating member (34) being intended to orient the passage of the heat transfer fluid between a heat exchanger (30) and a bypass (35).
8. Système d’alimentation (17) selon la revendication précédente, dans lequel le système de régulation thermique (18) comprend une première branche (36) apte à réguler la température de la pile à combustible (1). 8. Power supply system (17) according to the preceding claim, in which the thermal regulation system (18) comprises a first branch (36) able to regulate the temperature of the fuel cell (1).
9. Système d’alimentation (17) selon la revendication 8, dans lequel le système de régulation thermique (18) comprend une deuxième branche (38) apte à réguler la température au sein de l’évaporateur (4). 9. Supply system (17) according to claim 8, in which the thermal regulation system (18) comprises a second branch (38) able to regulate the temperature within the evaporator (4).
10. Procédé d’alimentation en hydrogène d’une pile à combustible (1), comprenant une étape d’acheminement de l’hydrogène à l’évaporateur (4), une étape d’évaporation et de montée en pression de l’hydrogène et une étape de transmission de l’hydrogène à la pile à combustible (1). 10. A method of supplying hydrogen to a fuel cell (1), comprising a step of conveying the hydrogen to the evaporator (4), a step of evaporating and increasing the pressure of the hydrogen and a step of transmitting hydrogen to the fuel cell (1).
11. Procédé d’alimentation selon la revendication précédente en combinaison avec la revendication 6, comprenant une sous-étape de contrôle de pression, cette sous-étape de contrôle étant au moins en partie assurée par l’au moins une vanne (5, 5b). 11. Supply method according to the preceding claim in combination with claim 6, comprising a pressure control sub-step, this control sub-step being at least partly ensured by the at least one valve (5, 5b ).
12. Véhicule électrique, étant équipé d’un système d’alimentation (17) selon l’une quelconque des revendications 1 à 9 et/ou étant alimenté en hydrogène selon un procédé d’alimentation selon l’une quelconque des revendications 10 et 11. 12. Electric vehicle, being equipped with a supply system (17) according to any one of claims 1 to 9 and / or being supplied with hydrogen according to a supply method according to any one of claims 10 and 11 .
PCT/EP2022/076449 2021-09-28 2022-09-22 System for supplying hydrogen to a fuel cell WO2023052249A1 (en)

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FRFR2110224 2021-09-28
FR2110224A FR3127641B1 (en) 2021-09-28 2021-09-28 Hydrogen supply system for a fuel cell

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Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2005135650A (en) * 2003-10-28 2005-05-26 Mitsubishi Heavy Ind Ltd Hydrogen plant equipped with power generation system utilizing natural energy
KR102235626B1 (en) * 2019-12-06 2021-04-06 한국철도기술연구원 Hydrogen fuel storage system and method of storing hydrogen fuel using the same
CN113258105A (en) * 2021-04-22 2021-08-13 四川荣创新能动力***有限公司 Control method of liquid hydrogen fuel cell waste heat recovery system

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2005135650A (en) * 2003-10-28 2005-05-26 Mitsubishi Heavy Ind Ltd Hydrogen plant equipped with power generation system utilizing natural energy
KR102235626B1 (en) * 2019-12-06 2021-04-06 한국철도기술연구원 Hydrogen fuel storage system and method of storing hydrogen fuel using the same
CN113258105A (en) * 2021-04-22 2021-08-13 四川荣创新能动力***有限公司 Control method of liquid hydrogen fuel cell waste heat recovery system

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FR3127641B1 (en) 2024-04-26
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