HYDROGEN SUPPLY CIRCUIT FOR A FUEL CELL FOR AN ELECTRIC VEHICLE WITH A HYDROGEN FUEL CELL AND CORRESPONDING ELECTRIC VEHICLE.

Abstract

This hydrogen supply circuit for a hydrogen fuel cell in a hydrogen fuel cell electric vehicle comprises a hydrogen tank (15) and a hydrogen circuit (16) including a tank filling circuit (17) comprising a filling pipe (18) having a filling end fixed relative to the vehicle body and a distribution circuit (19) which communicates with the fuel cell. The filling circuit and the distribution circuit are connected upstream of a tank opening and closing control valve (27) provided on the tank (15). The filling circuit includes a non-return valve (26) configured to prevent backflow of hydrogen from the tank to the filling circuit. Figure for abbreviation: Fig 3

Description

Title of the invention: HYDROGEN SUPPLY CIRCUIT FOR A FUEL CELL FOR ELECTRIC VEHICLES POWERED BY HYDROGEN FUEL CELLS AND CORRESPONDING ELECTRIC VEHICLE. technical field

[0001] The present invention relates to an electric motor vehicle with a hydrogen fuel cell. It relates more particularly to a hydrogen supply circuit for a hydrogen fuel cell in an electric motor vehicle with a hydrogen fuel cell. Previous techniques

[0002] Electric vehicles currently in circulation are mainly vehicles whose powertrain energy source is a battery. They are commonly called BEVs (English acronym for "Battery Electric Vehicles").

[0003] In parallel with BEVs, some motor vehicle manufacturers are beginning to develop electric vehicles with two energy sources: a battery and a fuel cell (FC) powered by hydrogen from a hydrogen tank. These vehicles are commonly called "hydrogen fuel cell electric vehicles," or FCEVs (for "Fuel Cell Electric Vehicle").

[0004] By incorporating hydrogen in addition to a battery, FCEVs offer a long range while optimizing the capacity of the onboard traction battery, thereby controlling its size and associated weight. Furthermore, refueling with hydrogen is as quick as refueling with conventional carbon-based fuels, taking only a few minutes.

[0005] Whatever the operating temperatures of these vehicles, the thermal management between the traction battery and the heat produced by the operation of the fuel cell makes it possible to guarantee stable and repeatable range and motor power despite a very variable temperature range which is penalizing for simple electric vehicles, i.e. not equipped with a fuel cell.

[0006] An example of FCEV vehicle architecture can be seen in [Fig.1].

[0007] In the example shown in [Fig. 1], in which a chassis 1 is depicted, the vehicle includes a high-pressure hydrogen tank 2 (for example, 700 bar) supplied from a filling pipe 3 (Arrow Fl) which opens onto the vehicle body, a fuel cell 4 supplied with hydrogen from the tank 2 (arrow F2), a battery 5 supplied with electrical energy from the fuel cell 4 and which powers an electric motor 6 which drives at least one wheel of the vehicle, for example the two rear wheels (arrow F3).

[0008] In order to increase the vehicle's range, it is desirable to be able to house a large hydrogen tank inside the vehicle.

[0009] One of the main problems associated with introducing hydrogen into a vehicle is related to safety management. Indeed, the hydrogen molecule (H2, dihydrogen) is the smallest existing molecule. The risk of leakage is therefore higher than for other gases.

[0010] Hydrogen is a highly flammable and reactive gas. It forms explosive mixtures with air above a low volume concentration, on the order of 4% (Lower Explosive Limit - LEL; Lower Flammable Limit - LFL).

[0011] The amount of energy required to ignite hydrogen (minimum ignition energy - MIE) is low, on the order of 0.01 mJ. For comparison, the energy of an electrostatic discharge is on the order of 10 mJ.

[0012] It is therefore necessary to avoid the risks of leakage and to avoid the lack of ventilation, in particular around the so-called "high pressure" part of the hydrogen circuit, which is the most critical.

[0013] Indeed, the hydrogen circuit includes a first portion 7 extending from the filling pipe to the tank (the so-called filling or "refuelling" part) and a second portion 8 extending from the tank to the fuel cell (the so-called distribution or "defuelling" part).

[0014] The distribution portion itself comprises three parts, each characterized by a different pressure level between the reservoir and the fuel cell.

[0015] It comprises a high-pressure section in which, in operation, the hydrogen stored in the tank is distributed at a high nominal pressure, for example 700 bar, from the tank to a main pressure regulator (not shown); a medium-pressure section between the main pressure regulator and an internal expansion valve in the fuel cell module, in which the hydrogen is then distributed between 12 and 20 bar, depending on the characteristics of the fuel cell; and a low-pressure section between the expansion valve of the fuel cell module and the stack of electrochemical cells of the fuel cell, in which the hydrogen is finally distributed at a pressure of less than 3 bar.

[0016] In the event of a leak, the mass flow rate of hydrogen released into the atmosphere is directly proportional to the gas pressure in the pipes. Consequently, the high-pressure section of the circuit is by far the most dangerous in the event of a leak.

[0017] In hydrogen circuits, the filling circuit is connected to the distribution circuit, in the high-pressure zone, between an "OTV" (On Tank Valve) control valve for opening and closing the tank, which provides the interface between the tank and the hydrogen circuit, and a main pressure regulator which reduces the pressure from "high" (up to 700 bar) to "medium" pressure (approximately 16 bar), at which point the hydrogen moves from the tank to the fuel cell.

[0018] The OTV valve is a solenoid valve that opens during refueling and remains closed until the fuel cell is started. It is then switched to the open position when hydrogen is being distributed to the fuel cell. Outside of the refueling and distribution phases, particularly when the vehicle is stopped, it is switched to the closed position.

[0019] The filling tube is equipped with a filling nozzle attached to the vehicle body and which is closed when filling is complete.

[0020] This nozzle, which is hermetically sealed during dispensing, ensures that hydrogen is not forced back into the filling circuit during dispensing.

[0021] In the event of an impact, the filling nozzle is likely to be damaged. There is therefore a risk that hydrogen may be forced back into the filling circuit, particularly due to the high pressure present in the distribution circuit. Description of the invention

[0022] The object of the invention is to overcome the aforementioned drawbacks.

[0023] The invention therefore relates to a hydrogen supply circuit for a hydrogen fuel cell for an electric vehicle with a hydrogen fuel cell, comprising a hydrogen tank and a hydrogen circuit comprising a tank filling circuit including a filling pipe having a filling end fixed relative to the vehicle body and a distribution circuit which communicates with the fuel cell, the filling circuit and the circuit being connected in communication upstream of a valve provided on the tank.

[0024] The filling circuit includes a check valve configured to prevent backflow of hydrogen from the tank to the filling circuit.

[0025] In one embodiment, the non-return valve is located where the filling circuit is connected to the distribution circuit.

[0026] Advantageously, the filling circuit is connected to the distribution circuit between the control valve for opening and closing the tank and a pressure regulator.

[0027] The invention also relates to an electric motor vehicle with a hydrogen fuel cell comprising a power supply circuit as defined above. Brief description of the drawings

[0028] Other objects, features and advantages of the invention will become apparent from the following description, given solely by way of non-limiting example, and made with reference to the accompanying drawings in which:

[0029] - Fig. 1 is a perspective view of the chassis of a vehicle according to the state of the technique;

[0030] - Fig. 2 is a perspective view of a vehicle chassis from one aspect of the invention, showing the placement of the hydrogen tank, fuel cell, traction battery, and powertrain; and

[0031] - Figure 3 illustrates the arrangement of a conforming hydrogen supply circuit to the invention. Detailed description

[0032] Figure 2 shows an electric hydrogen fuel cell motor vehicle according to the invention and in particular the chassis 10 of the vehicle on which is fixed a powertrain 11 of the vehicle intended to drive at least one drive wheel of the vehicle, here the two rear wheels of the vehicle.

[0033] The powertrain includes in particular an electric machine and an inverter positioned at the rear axle 12 of the vehicle.

[0034] The vehicle is a "hydrogen fuel cell electric vehicle", or FCEV. The powertrain thus comprises two energy sources, namely at least one high-voltage battery 13 and at least one fuel cell module (FC) 14, the battery being able to be recharged either from the fuel cell, while driving the vehicle, or from an electrical power supply network, while parked.

[0035] The high-voltage battery 13 is advantageously located under the floor of the vehicle.

[0036] The fuel cell module 14 is located under the rear seats, i.e. under the second row seats. It is supplied with hydrogen from a high-pressure hydrogen tank 15 integrated transversely in the front compartment of the vehicle and in a position set back from the front face which is more exposed to crash stresses.

[0037] The tank is thus located in an advanced position relative to the vehicle's passenger compartment, at the level of the front axle, while being positioned further back relative to the front of the vehicle exposed to frontal impacts.

[0038] With reference to [Fig.3] which shows the hydrogen tank 15 and its main components, the hydrogen tank 15 is connected to a hydrogen circuit 16, which supplies the hydrogen stored at high pressure in the tank 15 to the fuel cell module.

[0039] The hydrogen circuit includes a filling circuit 17 extending from a filling pipe 18 (or "refuelling" pipe) to the tank 15 and a distribution circuit 19 extending from the tank 15 to the fuel cell (or "defuelling" pipe).

[0040] The distribution circuit 19 comprises a high-pressure section 20 in which, during operation, the hydrogen stored in the tank is distributed at a nominal high pressure, for example 700 bar, and reaches a distribution regulator 21 consisting of a main pressure regulator; a medium-pressure section 22 between the main pressure regulator and an internal pressure regulator in the fuel cell module, in which the hydrogen is then distributed between 12 and 20 bar, depending on the characteristics of the fuel cell; and a low-pressure section (not shown) between the pressure regulator of the fuel cell module and the stack of electrochemical cells of the fuel cell, in which the hydrogen is finally distributed at a pressure below 3 bar.

[0041] The filling tube 18 includes an end having a filling nozzle 25 fixed to the vehicle body, which is open during filling and closed during hydrogen distribution.

[0042] The opposite end of the filling pipe communicates with the filling circuit, which communicates with the high-pressure part of the distribution circuit 19.

[0043] In order to avoid any risk of hydrogen backflow in the event of a malfunction of the filling pipe, in particular of the filling nozzle 25 following an impact, the filling circuit 17 includes a non-return valve 26 which is active towards the filling circuit 17. The non-return valve 26 is inserted in the filling circuit 17 so as to prevent any backflow of hydrogen from the tank and from the high-pressure part of the distribution circuit towards the filling circuit.

[0044] The non-return valve 26 is in this regard mounted in the area of ​​the filling circuit 17 connected to the distribution circuit, between the filling nozzle 25 and an "OTV" valve 27 of the tank (for "On Tank Valve"), creating the interface between the tank and the hydrogen circuit 16.

[0045] The addition of a non-return valve 26 significantly limits hydrogen leakage. Indeed, in the event of displacement of the filling circuit, the filling tube 18 or the nozzle 25, and / or in the event of damage to the connection between the filling circuit 17 and the nozzle 25, the backflow of hydrogen towards the filling circuit remains prohibited due to the presence of the check valve 26 and, ultimately, only the portion of the filling circuit 17 between the valve 26 and the nozzle 25 is emptied of hydrogen.

[0046] This aspect is all the more important because the filling circuit is the outermost part of the hydrogen circuit, as the filling pipe is fixed to the surface of the body to allow for hydrogen refueling. Consequently, the filling circuit is the part of the hydrogen circuit most exposed in the event of impacts likely to damage the circuit and cause a hydrogen leak.

Claims

Demands

1. Hydrogen supply circuit of a hydrogen fuel cell for an electric hydrogen fuel cell vehicle, comprising a hydrogen tank (15) and a hydrogen circuit (16) comprising a tank filling circuit (17) including a filling pipe (18) having a filling end fixed relative to the vehicle body and a distribution circuit (19) which communicates with the fuel cell, the filling circuit and the circuit being connected in communication upstream of a tank opening and closing control valve (27) provided on the tank (15), characterized in that the filling circuit includes a non-return valve (26) configured to prohibit backflow of hydrogen from the tank to the filling circuit.

2. Supply circuit according to claim 1, wherein the check valve (26) is disposed at the point where the filling circuit (17) is connected to the distribution circuit (19).

3. Supply circuit according to any one of claims 1 and 2, wherein the filling circuit (17) is connected to the distribution circuit between the valve (27) of the tank and a pressure regulator (21).

4. Hydrogen fuel cell electric motor vehicle, characterized in that it comprises a power supply circuit according to any one of claims 1 to 3.

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