FR2863779A1 - DEVICE AND METHOD FOR CONTROLLING THE TEMPERATURE OF A FUEL CELL SYSTEM ONBOARD A MOTOR VEHICLE. - Google Patents

Abstract

Device for regulating the temperature of an on-board fuel cell system on board a motor vehicle, comprising a circulation circuit (2) for a heat transfer fluid for the thermal regulation of the system, an electronic control unit (24) ), a pump (3) controlled by the electronic control unit (24), and a plurality of temperature sensors (4, 5, 6, 7) of which one (4) is placed at the output of the battery combustible. The circulation circuit (2) passes through the fuel cell (1) and a pre-anodic condenser (8), and comprises a first plurality of control valves (9, 10, 11, 12) controlled by the control unit electronics (24) to maintain, in nominal operation, a temperature (Topt) in the fuel cell (1) within a temperature range.

Description

2863779 1

  The present invention relates to a device and a method for regulating the temperature of an onboard fuel cell system onboard a device. a motor vehicle.

  Fuel cells are used to provide energy either in stationary installations or in the aeronautical or automobile field. The development of these batteries for integration into motor vehicles highlights particular constraints.

  Fuel cell devices, when embedded in motor vehicles, are designed according to the constraints of the vehicle, including dimensional constraints. In addition, the cooling circuit of these devices must be sized for a speed of 165 km / h and an outside temperature of 45 C, so that there are no problems even under these conditions of use. It must be possible to increase, under certain high conditions of use of the vehicle, the temperature of the fuel cell at temperatures above 100 C, which requires the ability to produce a membrane that can operate at this temperature level without degrading during the average life of the vehicle.

  Various solutions have already been devised for managing the temperature of a fuel cell.

  In this regard, reference may be made to US patent applications 2002/0037447 and EP 0 999 078 which describe devices for managing the temperature of a heat transfer fluid circulation circuit of a vehicle comprising a fuel cell. These devices can not, however, adapt the temperature of the fuel cell to the constraints of the system.

  The US Pat. No. 6,394,207 proposes a thermal management of a vehicle comprising a fuel cell, in particular for heating the fuel cell during cold weather and for heating or cooling other elements, without fine management of the temperature of the fuel cell. the fuel cell.

  The patent application EP 1 187 242 proposes a thermal management of the fuel cell, but without in particular optimizing its performance in nominal mode.

  Thus, in view of the above, the object of the invention is to bring about as quickly as possible and to maintain a fuel cell in a temperature range, in which the performance of the fuel cell is optimal, while respecting the thermal constraints of cooling.

  The invention therefore aims a device for regulating the temperature of a fuel cell system on board a motor vehicle. This device comprises a circulation circuit of a heat transfer fluid for the thermal regulation of the system, an electronic control unit, a pump controlled by the electronic control unit, and a plurality of temperature sensors, one of which is placed in position. output of the fuel cell. The circulation circuit passes through the fuel cell and a pre-anode condenser, and comprises a first plurality of control valves controlled by the electronic control unit so as to maintain, in nominal operation, a temperature in the fuel cell included in a predetermined range of temperatures.

  The operation of the fuel cell is then optimized and brought as quickly as possible to this optimum operating temperature range.

  For example, the first plurality of controlled control valves comprises a first three-way control valve and a first set of two-way control valves.

  In a preferred embodiment, the electronic control unit is able to maintain, in nominal operation, a temperature in the fuel cell, a temperature range being a function of the maximum temperature of use of the membrane of the fuel cell. Fuel cell.

  For example, the temperature range in which the performance of the fuel cell is optimal is the 80 C-90 C range.

  It is generally within this temperature range that a fuel cell, comprising a perfluorinated type membrane, embarked on board a motor vehicle, has an optimal performance.

  In an advantageous embodiment, the electronic control unit is adapted to control the pump and the first control valves for managing the heat transfer fluid flows so that the fuel cell operates at a temperature higher than the upper limit of said interval and less than a limit temperature, when it is necessary to increase the amount of heat energy exchanged with the outside air.

  In more advanced conditions of use of the vehicle, it is sometimes necessary to increase the operating temperature of the fuel cell, in order to be able to evacuate a greater thermal power with the outside air.

  In a preferred embodiment, said limiting temperature is a function of the maximum operating temperature of the fuel cell membrane.

  For example the temperature limit is about 110 C.

  In an advantageous embodiment, the circulation circuit also passes through a cooling radiator for the heat transfer fluid, a first charge air radiator, a second charge air radiator, a fan heater, an anode condenser, a cathode condenser. , an electric motor, and electronic components. The coolant circulation circuit 2863779 comprises, in addition, a second plurality of control valves controlled by the electronic control unit, for maintaining a temperature of the charge air radiators, a temperature of the heater, a pre-anodic condenser temperature, anode condenser temperature, a cathode condenser temperature, an electric motor temperature, and a temperature of the electronic components, below a critical temperature, to avoid degradation of these elements.

  Indeed, some of the elements of the fuel cell system must not exceed a critical temperature, beyond which they would be damaged.

  For example, the second plurality of controlled control valves comprises a three-way control valve and a second set of two-way control valves.

  In a preferred embodiment, the critical temperature is about 65 C.

  The invention also proposes a method for regulating the temperature of an on-board fuel cell system on a motor vehicle. A first plurality of control valves and a pump of a heat transfer fluid circulating circuit are controlled to maintain, in nominal operation, a temperature in the fuel cell within a predetermined range of temperatures.

  In a preferred embodiment, the pump and a second plurality of control valves are controlled to manage the flow rates of heat transfer fluid so that the temperature in the fuel cell is greater than the upper limit of said interval and less than a limit temperature, when it is necessary to increase the amount of thermal energy exchanged with the outside air.

  In an advantageous embodiment, the pump is controlled, a second plurality of control valves for managing the flow of heat transfer fluid to maintain the temperature of the charge air radiators, the temperature of a heater, the temperature of a pre-anodic condenser, the temperature of an anode condenser, the temperature of a cathode condenser, the temperature of an electric motor, and the temperature of an electronics below a critical temperature, in order to avoid a degradation of these elements.

  Other objects, features and advantages of the invention will become apparent on reading the following description, given solely by way of nonlimiting example, and with reference to the appended drawing on which is represented a regulating device according to the invention. .

  In the figure, there is shown the general architecture of a temperature control device according to the invention. this device is intended to be on board a motor vehicle equipped with a fuel cell 1 to regulate the temperature.

  As seen in this figure, the control device comprises a circulation circuit 2 of a coolant for the thermal regulation of the fuel cell system. The fuel cell system of the vehicle is constituted by a conventional fuel cell system. It will not be described in detail. It will be noted, however, that it is equipped with means for supplying the cell 1 with hydrogen and with an air compression unit for supplying the cell 1 with oxygen (not shown).

  The regulating device is equipped with a pump 3 for circulating the coolant. A plurality of temperature sensors 4, 5, 6 and 7 are provided for measuring the temperature of the fluid in the circuit. One of the sensors referenced 4 measures the temperature inside the fuel cell 1. The device 2863779 6 also comprises a pre-anodic condenser 8, a first three-way control valve 9, and a first set of control valves. two-way control system 10, 11 and 12, and a second three-way control valve 13 and a second set of two-way control valves 14 and 15. The device further comprises a first and a second charge air radiator (RAS) 16 and 17, a heater 18 and a radiator 19. All these radiators 8, 16, 17, 19 and the heater 18 are heat exchangers. The device also manages the temperature of an anode condenser 20, a cathode condenser 21, an electric motor 22, and a set of electronic components 23.

  In addition, the device comprises an electronic control unit (ECU) 24. The three-way control valves 9 and 13 are respectively connected to the electronic control unit, 24 by connections 25 and 26, and the two control valves 10, 11, 12, 14, and 15 are respectively connected to the electronic control unit 24 by connections 27, 28, 29, 30 and 31. The electronic control unit 24 is also connected to each of the sensors of 4, 5, 6 and 7, respectively by connections 32, 33, 34 and 35, as well as the electric motor 22, the electronics 23, and the pump 3, respectively by connections 36 and 37 and 38. .

  The circulation circuit 2 of the coolant comprises a branch 39 passing through the fuel cell 1 and a branch 40, parallel to the branch 39 and comprising the two-way valve 12, which meet in a branch 41. A branch 42 passing through the first charge air radiator separates into two branches 40 and 43, the branch 43 comprising the two-way valve 11. A branch 44 connected to the three-way valve 9, separates into two parallel branches 42 and 45, the branch 45 comprising the two-way valve 10 and joining the branch 43 to form the branch 39. Another branch 46 connected to the three-way valve 9 joins the branch 41 in a branch 47. The branch 2863779 7 47 separates into two branches 48 and 49. The branch 48 separating into several branches, one of which includes the two-way valve 15 and joined the radiator 19. The branch 49 through the heater 18, comprises a nozzle 50a, and joined a branch 62 in a branch 49b. The branch 49b joins a branch 51 passing through the electric motor 22 and the anode condenser 20 into a branch 52. The branch 52 and a branch 53, passing through the electronics 23 and the cathode condenser 21, meet in a branch 54, comprising the pump 3 and the thermal sensor 6, and connected to the three-way valve 9. A branch 55 connects the radiator 19 to the three-way valve 13, and a branch 56 comprising the two-way valve 14 joins a branch 57 coming out of the radiator 19. a branch 58, which passes through the third charge air radiator 17 and which comprises the thermal sensor 7.

  When the coolant passes through the radiator 19, the flow of heat transfer fluid leaving the branch 55 is much greater than that exiting through the branch 57. The branch 58 splits into two branches 51 and 53. A branch 59 connected to the valve three lanes 13 splits into two branches 60 and 61. The branch 60 passes through the first charge air cooler 16 and joins the branch 61 to the branch 62. The branch 61 comprises a nozzle 63.

  The branch 61 makes it possible not to pass a too high flow of heat transfer fluid in the first charge air radiator 16. The nozzles 50a and 63 can regulate the flow rates in their branches. The branch 61 allows in particular to limit the pressure drop of the circuit when the flow in the branch 55 is important.

  In addition, the electronic control unit 24 comprises control means 64 able to control the two and three-way valves 10, 11, 14, 15, 9 and 13 to manage the temperatures in the fuel cell 1 and in other elements of the system, according to information transmitted in particular by the different temperature sensors 4, 5, 6 and 7.

  In a start-up mode of the fuel cell 1, it is important to raise the temperature in the stack 1 as quickly as possible to an optimum operating temperature within the temperature range 80 C-90 C Indeed, when the fuel cell operates at lower temperatures, its efficiency is significantly lower.

  To raise the temperature in the cell 1, the flow rate of the heat transfer fluid in the cell 1 must be low in order to eliminate as little as possible the thermal energy produced by the electrochemical exothermic reactions. The control means 64 then control in a starting phase the two-way valves 10, 11 and 12, as well as the three-way valve 9, in order to adjust the coolant flow rate in the branch 39 passing through the fuel cell 1, from the temperature measurements of the sensors 4 and 5. For example, it closes the valves 10 and 11 to have a zero flow of heat transfer fluid through the stack 1. It can even be considered to circulate a heat transfer fluid heated in the branch 39 passing through the cell 1, to heat it up even more rapidly, by closing the valves 10 and 12, and by opening the valve 11.

  The heat transfer fluid is then heated with a low flow rate passing through the charge air cooler 8 of the branch 42. The control means then manage the pump 3 and the openings of the various valves in order to adapt the flow rate and the temperature of the heat transfer fluid therethrough. the battery 1, as a function of the measurements transmitted by the temperature sensors 4 and 5 to the electronic control unit 24.

  In nominal operation, the control means 64 manage the pump 3 and the openings of the various valves to adapt the flow rate and the temperature of the heat transfer fluid passing through the cell 1, as a function of the measurements transmitted by the temperature sensors 4 and 5 to the electronic control unit 24, in order to maintain the temperature Top, in the stack in the range 2863779 9 temperatures 80 C-90 C, corresponding to an optimal operation of the battery 1.

  When the energy demanded at the fuel cell 1 is too small for the electrochemical exothermic reactions to release enough thermal energy to maintain the temperature in the battery 1 within this temperature range, the control means 64 can close the valves 10. and 11 to have a zero flow of heat transfer fluid through the stack 1, so as not to cool. The control means 64, in this case, can furthermore heat the heat transfer fluid by circulating it in the charge air radiator 8, by closing the valves 10 and 12, and by opening the valve 11.

  When the cooling becomes critical, that is to say when the thermal energy to be evacuated is too high when the vehicle is moving fast or when the external temperature is high and decreases the amount of heat energy removed, the control means 61 manage the pump 3 and the openings of the different valves to adapt the flow rate and the temperature of the heat transfer fluid passing through the stack 1, according to the measurements transmitted by the temperature sensors 4 and 5 to the electronic control unit 24, so that the Stack 1 can operate at a temperature close to a temperature limit Tiim, for example a value of about 110 C, which allows the radiator 19 to evacuate more thermal energy by increasing the temperature difference between outside air and heat transfer fluid in the radiator 19. The temperature limit Tain, is a function of the maximum temperature of use of the membrane of the battery.

  While ensuring the temperature rise of the battery 1 to an optimum temperature T pt within the temperature range defined above, it is necessary to ensure the cooling of the organs to remain at temperatures below a critical temperature Terit, for example of the order of 65 C. When the heat transfer fluid reaches a temperature close to Tcr; tcrit-10 C, for example, the control means 60 receiving temperature measurements from the temperature sensors 6 and 7 control the two-way and three-way valves to cool the coolant. The control means 64 close the two-way valve 14 and open the two-way valve 15, in order to cool the coolant by passing through the radiator 19. In addition, they control the three-way valve 13 so that the fluid circulates between the radiator 19 and in the charge air radiator 16 by the branches 55 and 60. The heat transfer fluid is thus cooled before passing through the charge air radiator 2.

  The invention thus makes it possible to manage the temperature in a fuel cell on board a motor vehicle in order to optimize its operation.

  The invention also makes it possible to manage the temperature in the rest of the fuel cell system, in order to avoid equipment damage that could be caused by too high a temperature.

Claims (13)

  1. Device for regulating the temperature of a fuel cell system on board a motor vehicle, comprising a circulation circuit (2) for a heat transfer fluid for the thermal regulation of the system, an electronic control unit (24), a pump (3) controlled by the electronic control unit (24), and a plurality of temperature sensors (4, 5, 6, 7) of which one (4) is placed at the output of the fuel cell (1), characterized in that said circulation circuit (2) passes through the fuel cell (1) and a pre-anodic condenser (8), and comprises a first plurality of control valves controlled by the electronic control unit (24) to maintain, in nominal operation, a temperature (Tops) in the fuel cell (1) within a predetermined temperature range.   2. Device according to claim 1, characterized in that the first plurality of controlled control valves comprises a first three-way control valve (9) and a first set of two-way control valves (10, 11, 12).   3. Device according to claim 1 or 2, characterized in that the electronic control unit (24) is adapted to maintain, in nominal operation, a temperature (Tops) in the fuel cell (1) in a range of temperatures being a function of the maximum operating temperature of the fuel cell membrane (1).   4. Device according to claim 3, characterized in that the temperature range in which the performance of the fuel cell is optimal is the interval 80 C-90 C.   5. Device according to any one of claims 1 to 4, characterized in that the electronic control unit (24) is adapted to control the pump 2863779 12 (3) and the first control valves (9, 10, 11, 12) for managing the coolant flow rates so that the fuel cell (1) operates at a temperature above the upper limit of said range and below a limiting temperature (Tiim), when it is necessary to increase the amount of thermal energy exchanged with the outside air.   6. Device according to claim 5, characterized in that said limit temperature is a function of the maximum operating temperature of the membrane of the fuel cell (1).   7. Device according to claim 6, characterized in that said limit temperature (Tlim) is about 110 C.   8. Device according to any one of claims 1 to 7, characterized in that said circulation circuit (2) also passes through a cooling radiator (19) of the heat transfer fluid, a first air radiator supâ mi tfôh (16), a second charge air cooler (17), a heater (18), an anode condenser (20), a cathode condenser (21), an electric motor (22), and electronic components (23) , and further comprises a second plurality of control valves controlled by the electronic control unit (24), for maintaining a temperature of the charge air radiators (16, 17), a temperature of the heater (18) , a pre-anode condenser temperature (8), an anode condenser temperature (20), a cathode condenser temperature (21), a temperature of the electric motor (22), and a temperature of the electronic components (23), lower at a critical temperature (Tcr it), in order to avoid a degradation of these elements.   9. Device according to claim 8, characterized in that the second plurality of controlled control valves comprises a three-way control valve (13) and a second set of two-way control valves (14, 15).   2863779 13 10. Device according to claim 9, characterized in that said critical temperature (Tcr; t) is about 65 C.   11. A method for regulating the temperature of an on-board fuel cell system on a motor vehicle, characterized in that a first plurality of control valves and a pump (3) of a circulation circuit (2) of a heat transfer fluid for maintaining, in nominal operation, a temperature (T Pt) in the fuel cell (1) within a predetermined temperature range.   12. Method according to claim 11, characterized in that the pump (3) and a second plurality of control valves are controlled to manage the flows of coolant so that the temperature in the fuel cell (1) is greater than the upper limit of said range and less than a limit temperature (Tiim), when it is necessary to increase the amount of heat energy exchanged with the outside air.   Method according to claim 12, characterized in that the pump (3) is controlled, a second plurality of regulating valves for controlling the coolant flows to maintain the temperature of the charge air radiators ( 16, 17), the temperature of a heater (18), the temperature of a pre-anode condenser (8), the temperature of an anode condenser (20), the temperature of a cathode condenser (21), the temperature of an electric motor (22), and the temperature of electronic components (23) below a critical temperature (Terit), in order to avoid a degradation of these elements.