JP5273435B2 - Fuel cell system - Google Patents

Description

  The present invention relates to a fuel cell system.

Generally, in a vehicle equipped with a fuel cell system, a traction motor is driven by supplying power from the fuel cell and the secondary battery. Here, the direct current output from the fuel cell is input to the traction inverter via a cable, converted into a three-phase alternating current by the traction inverter, and then supplied to the traction motor. A cell monitor for detecting the voltage of each cell included in the cell stack of the fuel cell (cell stack) is disposed between the fuel cell and the traction inverter (see Patent Documents 1 and 2 below).
JP 2006-185868 A JP 2007-048609 A

  By the way, since a direct current with a large current value flows through the cable connecting the fuel cell and the traction inverter, it is necessary to use a thick and heavy cable. Furthermore, since a cell monitor is disposed between the fuel cell and the traction inverter, the cable length of a thick and heavy cable becomes long. Use of such a cable hinders space efficiency and weight reduction.

  The present invention has been made to solve the above-described problems caused by the prior art, and an object of the present invention is to provide a fuel cell system capable of improving the space efficiency and reducing the weight.

  In order to solve the above-described problems, a fuel cell system according to the present invention has a cell stack formed by stacking a plurality of cells, and generates a power by an electrochemical reaction between an oxidizing gas and a fuel gas; DC voltage conversion comprising: a cell voltage detection unit that detects the voltage of a part of the cells of the cell stack; and a DC voltage conversion unit that boosts a DC voltage input from the fuel cell and outputs the boosted voltage to the power consuming device side And the cell voltage detector are arranged on any one of the plates constituting the outer surface of the fuel cell.

  According to the present invention, since the DC voltage converter can be disposed on any of the plates constituting the outer surface of the fuel cell, the distance between the fuel cell and the DC voltage converter can be shortened. The section through which a direct current having a large current value output from the fuel cell flows can be shortened. In addition, since the DC voltage conversion unit is arranged adjacent to the fuel cell, the output voltage of the fuel cell can be kept constant. Therefore, it is necessary to provide the cell voltage detection unit corresponding to all the cells. The cell voltage detector can be provided only for some cells.

In the fuel cell system, by adjusting the charge reservoir unit that charges electric power generated by the fuel cell, a DC voltage input from the charge reservoir unit outputs to the power consuming device side, the DC voltage converter or power consumption a charge reservoir section for the DC voltage converter which outputs the charge reservoir portion by adjusting the DC voltage inputted from the apparatus may further include a.

  In the fuel cell system, the plate may constitute any surface of the outer surface of the fuel cell other than the surface positioned on the upper side when the fuel cell is installed.

  By doing in this way, a DC voltage conversion part and a cell voltage detection part can be arrange | positioned on the plate which comprises surfaces other than the upper surface side of a fuel cell.

  The said fuel cell system WHEREIN: The said plate may comprise the surface located in the lower part side when installing a fuel cell among the outer surfaces of a fuel cell.

  By doing in this way, a DC voltage conversion part and a cell voltage detection part can be arrange | positioned at the lower surface side of the plate which comprises the lower surface of a fuel cell.

  In the fuel cell system, the cell voltage detection unit includes a plurality of detection units that respectively detect voltages of end cells located at end portions in the stacking direction of the cell stack, and the DC voltage conversion unit includes the detection unit. It is good also as arrange | positioning between.

  By doing in this way, a direct-current voltage conversion part can be arranged in the space formed between a plurality of detection parts.

  In the fuel cell system, the plate may be made of a metallic material.

  By doing in this way, the heat | fever which generate | occur | produces from a direct-current voltage converter can be radiated by conducting a plate.

  According to the present invention, space efficiency can be improved and weight reduction can be achieved.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, preferred embodiments of a fuel cell system according to the invention will be described with reference to the accompanying drawings. This embodiment demonstrates the case where the fuel cell system which concerns on this invention is used as a vehicle-mounted power generation system of a fuel cell vehicle (FCHV; Fuel Cell Hybrid Vehicle).

  With reference to FIG. 1, the structure of the fuel cell system in this embodiment is demonstrated. FIG. 1 is a configuration diagram schematically illustrating a fuel cell system according to an embodiment.

  As shown in FIG. 1, a fuel cell system 1 includes a fuel cell 2 that generates electric power by an electrochemical reaction between an oxidizing gas that is a reactive gas and the fuel gas, and an oxidizing gas that supplies air as the oxidizing gas to the fuel cell 2. It has a piping system 3, a hydrogen gas piping system 4 that supplies hydrogen as fuel gas to the fuel cell 2, a power system 5 that charges and discharges the power of the system, and a control unit 6 that controls the entire system. The fuel cell 2 and the hydrogen gas piping system 4 constitute a hydrogen gas supply mechanism.

  The fuel cell 2 is, for example, a polymer electrolyte fuel cell, and includes a cell stack 21 (cell stack) formed by stacking a large number of cells. Each cell has an air electrode on one surface of an electrolyte made of an ion exchange membrane, a fuel electrode on the other surface, and a structure having a pair of separators so as to sandwich the air electrode and the fuel electrode from both sides. It has become. In this case, hydrogen gas is supplied to the hydrogen gas flow path of one separator, oxidizing gas is supplied to the oxidizing gas flow path of the other separator, and electric power is generated by the chemical reaction of these reaction gases.

  The fuel cell 2 includes an end plate 22 provided outside each of the end cells located at both ends of the cell stack 21, a tension plate 23 that fastens the end plates 22 on the upper end side of the cell stack 21, a cell A base plate 24 (plate) that fastens both end plates 22 on the lower end side of the laminated body 21 is provided. By fastening the end plates 22 using the tension plate 23 and the base plate 24, the cell stack 21 is held in a state where a predetermined compressive force is applied in the cell stacking direction.

  A fuel cell DC / DC converter 51 and a cell monitor 52, which will be described later, are disposed on the lower surface side of the base plate 24. The base plate 24 is made of a metallic material having a thermal conductivity equal to or higher than a predetermined value, such as aluminum. Thereby, since the heat generated from the DC / DC converter 51 can be conducted to the end plate 22 through the base plate 24 to be radiated, the cooling effect of the DC / DC converter 51 can be improved.

  By providing the base plate 24, the plate for arranging the DC / DC converter 51 and the cell monitor 52 and the tension plate can be realized by only one base plate 24. Therefore, the configuration of the fuel cell system 1 can be realized. While being able to simplify, the weight reduction of the fuel cell system 1 can be achieved.

  The oxidizing gas piping system 3 compresses air taken in through the filter 30 and sends out compressed air as oxidizing gas, and an air supply flow path 32 for supplying the oxidizing gas to the fuel cell 2. And an air discharge passage 33 for discharging the oxidizing off-gas discharged from the fuel cell 2.

  The hydrogen gas piping system 4 includes a hydrogen tank 40 as a fuel supply source storing high-pressure hydrogen gas, and a hydrogen supply channel 41 as a fuel supply channel for supplying the hydrogen gas in the hydrogen tank 40 to the fuel cell 2. And a circulation flow path 42 for returning the hydrogen off-gas discharged from the fuel cell 2 to the hydrogen supply flow path 41. The hydrogen supply channel 41 is provided with a main stop valve 43 that blocks or allows the supply of hydrogen gas from the hydrogen tank 40. The circulation channel 42 is provided with a hydrogen pump 44 that pressurizes the hydrogen off gas in the circulation channel 42 and sends it to the hydrogen supply channel 41 side.

Power system 5 includes a DC / DC converter 51 for a fuel cell (DC voltage converter), and the cell monitor 52 (cell voltage detection unit), a battery 53 (the charge reservoir unit), DC / DC converter 54 for the battery ( having a use charge reservoir section DC voltage converter), a traction inverter 55, a traction motor 56 (power unit), and various auxiliary inverters of which is not shown.

  The fuel cell DC / DC converter 51 is a direct current voltage converter, and has a function of boosting the direct current voltage input from the fuel cell 2 and outputting the boosted voltage to the traction inverter 55 on the power consuming device side. The output voltage of the fuel cell 2 is boosted by the DC / DC converter 51. Therefore, the current value of the direct current flowing through the cable connecting the DC / DC converter 51 and the traction inverter 55 is lower than the current value of the direct current flowing between the fuel cell 2 and the DC / DC converter 51. As a result, a cable that is thinner and lighter than the cable that connects the fuel cell 2 and the DC / DC converter 51 can be used as a cable that connects the DC / DC converter 51 and the traction inverter 55. In addition, since the DC / DC converter 51 is disposed on the base plate 24 of the fuel cell 2, the cable length of a thick and heavy cable connecting the electrode of the fuel cell 2 and the DC / DC converter 51 can be shortened. Thereby, the space efficiency of the fuel cell system 1 can be improved, and the weight of the fuel cell system 1 can be reduced.

  The cell monitor 52 detects the voltage of the end cell located at the end of the cell stack 21 in the stacking direction. By the way, since the DC voltage output to the traction inverter 55 can be kept constant by providing the fuel cell DC / DC converter 51, the cell monitor for detecting the voltage of each cell can be omitted. . However, if the cell voltage drops for some reason, there is a risk that the cell may fail, and in order to prevent such a failure, a cell monitor that monitors the voltage of some cells is provided. In the present embodiment, the cell monitors 52 are provided at two locations, and the voltages of the cells positioned at both ends of the cell stack 21 are detected by the cell monitors 52, respectively. As a result, a space can be provided between the cell monitors 52, and the DC / DC converter 51 can be disposed in this space. It can be shortened. In addition, since the cell monitor 52 need only be provided corresponding to the end cells without being provided corresponding to all cells, the space efficiency of the fuel cell system 1 can be improved, and the fuel cell system 1 Weight reduction can be achieved.

  As shown in FIG. 1, the fuel cell DC / DC converter 51 and the cell monitor 52 are disposed on the lower surface side of the base plate 24 positioned on the lower side of the fuel cell 2 when the fuel cell 2 is installed in the vehicle. However, disposing the DC / DC converter 51 and the cell monitor 52 on the lower surface side of the fuel cell 2 has the following advantages.

  The drainage channel for discharging the water generated by the fuel cell 2 needs to be provided at a position lower than the fuel cell 2. In general, the drainage channel is provided at a position adjacent to the fuel cell 2 and lower than the fuel cell. In other words, the fuel cell 2 is provided at a position adjacent to the drainage channel and higher than the drainage channel. Thus, by arranging the fuel cell 2 at a position higher than the drainage channel, an extra space is created in the lower portion of the fuel cell 2. Therefore, the DC / DC converter 51 and the cell monitor 52 are arranged below the fuel cell 2, and the DC / DC converter 51 and the cell monitor 52 are arranged in the extra space so that an extra space that can be formed below the fuel cell 2. Can be used effectively.

  Furthermore, when the fuel cell 2 is installed under the floor of the vehicle, the DC / DC converter 51 and the cell monitor 52 can be arranged in the extra space to maintain the height of the vehicle floor. At the same time, the center of gravity of the vehicle can be lowered. Further, the lower the vehicle floor surface, the larger the space in the vehicle can be secured and the product quality can be enhanced. Therefore, the high product quality can be maintained by maintaining the low floor surface.

  The battery 53 is configured such that battery cells are stacked and a constant high voltage is used as a terminal voltage, and surplus power can be charged or power can be supplementarily supplied under the control of a battery computer (not shown). The battery DC / DC converter 54 is a DC voltage converter, and adjusts (boosts) the DC voltage input from the battery 53 and outputs it to the traction inverter 55 on the power consuming device side, and a fuel cell. 2 or a function of adjusting (stepping down) the DC voltage input from the traction motor 56 and outputting it to the battery 53. Such a function of the DC / DC converter 54 realizes charging / discharging of the battery 53.

  The traction inverter 55 converts a direct current into a three-phase alternating current and supplies it to the traction motor 56. The traction motor 56 is, for example, a three-phase AC motor, and constitutes a main power source of a fuel cell vehicle on which the fuel cell system 1 is mounted. The auxiliary inverter is an electric motor control unit that controls driving of each motor, converts a direct current into a three-phase alternating current, and supplies the three-phase alternating current to each motor. The auxiliary inverter is, for example, a pulse width modulation type PWM inverter, which converts the DC voltage output from the fuel cell 2 or the battery 53 into a three-phase AC voltage in accordance with a control command from the control unit 6 and is generated by each motor. To control the rotational torque.

  The control unit 6 detects an operation amount of an acceleration operation member (accelerator or the like) provided in the fuel cell vehicle, and controls information such as an acceleration request value (for example, a required power generation amount from a power consumption device such as the traction motor 56). In response, the operation of various devices in the system is controlled. In addition to the traction motor 56, the power consuming device includes, for example, auxiliary equipment necessary for operating the fuel cell 2 (for example, the motor of the compressor 31 and the hydrogen pump 44), and various types of vehicles involved in traveling of the vehicle. This includes actuators used in devices (transmissions, wheel control devices, steering devices, suspension devices, etc.), air conditioning devices (air conditioners) for passenger spaces, lighting, audio, and the like.

  The control unit 6 physically includes, for example, a CPU, a ROM for storing control programs and control data processed by the CPU, a RAM mainly used as various work areas for control processing, and an input / output interface. And have. These elements are connected to each other via a bus. Various sensors such as a cell monitor 52, a current sensor, a voltage sensor, and a pressure sensor are connected to the input / output interface, and various sensors for driving the compressor 31, the main stop valve 43, the hydrogen pump 44, the traction motor 56, and the like. The driver is connected.

  The CPU receives the detection results of the various sensors via the input / output interface according to the control program stored in the ROM, and processes the various processes in the fuel cell system 1 by using the various data in the RAM. Control. Further, the CPU controls the entire fuel cell system 1 by outputting control signals to various drivers via the input / output interface.

  As described above, according to the fuel cell system 1 in the embodiment, the fuel cell DC / DC converter 51 can be disposed on the lower surface side of the base plate 24 constituting the lower surface of the fuel cell 2. The distance between the battery 2 and the DC / DC converter 51 can be shortened. Thereby, the length of the thick heavy cable for large currents connected between the electrode of the fuel cell 2 and the DC / DC converter 51 can be shortened. Therefore, the space efficiency of the fuel cell system 1 can be improved and the weight of the fuel cell system 1 can be reduced.

  Further, in addition to the battery DC / DC converter 54 provided in the conventional fuel cell, the fuel cell DC / DC converter 51 is disposed adjacent to the fuel cell 2 so that the output of the fuel cell 2 is output. Since the voltage can be held constant, there is no need to provide cell monitors corresponding to all the cells as in the conventional fuel cell, and the cell monitors 52 can be provided only for some of the cells. Thereby, the space efficiency of the fuel cell system 1 can be improved, and the weight reduction of the fuel cell system 1 can be achieved.

  In the above-described embodiment, the DC / DC converter 51 and the cell monitor 52 are arranged on the lower surface side of the base plate 24. However, the positions where the DC / DC converter 51 and the cell monitor 52 are arranged are not limited to this. The base plate 24 may be provided on any surface constituting the outer surface of the fuel cell 2 and disposed on the base plate 24. This makes it possible to shorten the cable length of the thick and heavy cable connecting the electrode of the fuel cell 2 and the DC / DC converter 51 as much as possible. In particular, if the DC / DC converter 51 can be arranged on a straight line connecting the total positive side electrode and the total negative side electrode of the fuel cell 2, the cable length of the thick and heavy cable described above can be minimized. .

  Further, it is not necessary to provide the DC / DC converter 51 and the cell monitor 52 on the same surface, and a base plate 24 is provided on each of the surfaces constituting the outer surface of the fuel cell 2, and each of the base plates 24 is provided on the base plate 24. It is good also as arranging. However, when the DC / DC converter 51 and the cell monitor 52 are arranged on the same surface, the base plate 24 can be made into one sheet, so that the weight can be further reduced.

  Further, since the DC / DC converter 51 and the cell monitor 52 are arranged at least at a position that does not protrude upward from the height of the upper surface of the fuel cell 2, the height of the floor surface can be maintained. The height can be maintained.

  Further, in each of the above-described embodiments, the case where the fuel cell system according to the present invention is mounted on a fuel cell vehicle has been described. However, various mobile bodies (robots, ships, aircrafts, etc.) other than the fuel cell vehicle are also described. The fuel cell system according to the present invention can be applied. Moreover, the fuel cell system according to the present invention can also be applied to a stationary power generation system used as a power generation facility for buildings (houses, buildings, etc.).

It is a lineblock diagram showing typically the fuel cell system in an embodiment.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Fuel cell system, 2 ... Fuel cell, 3 ... Oxidation gas piping system, 4 ... Hydrogen gas piping system, 5 ... Electric power system, 6 ... Control part, 21 ... Cell laminated body, 22 ... End plate, 23 ... Tension plate 24 ... Base plate, 51 ... DC / DC converter, 52 ... Cell monitor, 53 ... Battery, 54 ... DC / DC converter, 55 ... Traction inverter, 56 ... Traction motor.

Claims (5)

A fuel cell having a cell stack formed by laminating a plurality of cells and generating electric power by an electrochemical reaction between an oxidizing gas and a fuel gas;
A cell voltage detector for detecting a voltage of a part of the cells of the cell stack;
A DC voltage converter that boosts the DC voltage input from the fuel cell and outputs the boosted voltage to the power consuming device side;
The direct-current voltage conversion unit and the cell voltage detection unit are disposed on any plate constituting the outer surface of the fuel cell ,
The cell voltage detection unit includes a plurality of detection units that respectively detect voltages of end cells located at end portions in the stacking direction of the cell stack,
The DC voltage converter, the fuel cell system characterized Rukoto disposed between the detector. A charge reservoir unit that charges electric power generated by the fuel cell,
蓄 said current voltage input from the charge reservoir unit outputs to the power consuming device side, by adjusting the DC voltage input from the DC voltage converter or power consuming apparatus side outputs to the charge reservoir section A DC voltage converter for electrical parts;
The fuel cell system according to claim 1, further comprising:   3. The fuel cell according to claim 1, wherein the plate constitutes one of the outer surfaces of the fuel cell other than a surface positioned on an upper side when the fuel cell is installed. 4. system.   3. The fuel cell system according to claim 1, wherein the plate constitutes a surface located on a lower side when the fuel cell is installed, of the outer surface of the fuel cell. 4. The fuel cell system according to any one of claims 1 to 4 , wherein the plate is made of a metallic material.

Images