JP2020089010A - Fuel cell system - Google Patents

Abstract

To provide a fuel cell system which can prevent foreign matter inclusion into a cooling passage more effectively.SOLUTION: A fuel cell system 10 mounted on a vehicle includes: an FC assembly 18 having an FC stack 12 and a control unit 14 which controls the FC stack 12; a cooling mechanism 30 which cools the FC stack 12 by using a fully closed type cooling passage 32; and a reserve tank 50 provided at a position located in the middle of the cooling passage 32 and adjacent to the FC assembly 18, stores a coolant, and has an opening 52 communicating with the interior and a cap 54 which closes the opening 52; and a design cover 60 which covers the FC assembly 18 and the cap 54 of the reserve tank 50 from above.SELECTED DRAWING: Figure 3

Description

The present specification discloses a fuel cell system mounted on a vehicle, the fuel cell system including a fuel cell stack and a cooling mechanism for cooling the fuel cell stack.

Conventionally, a vehicle equipped with a fuel cell has been proposed. For example, Patent Document 1 proposes that a vehicle be equipped with a fuel cell system including a fuel cell stack, a reserve tank, and a control circuit. In Patent Document 1, the reserve tank is arranged above the fuel cell stack. With such a configuration, even when the cooling water is replenished to the reserve tank, it is possible to prevent the cooling water from being jetted from the cooling water replenishment port due to the head pressure.

The fuel cell stack, which generates electricity by an electrochemical reaction, is more likely to be adversely affected by foreign matter than an internal combustion engine or the like. Therefore, it is desired that the cooling flow path for cooling the fuel cell stack has a structure in which foreign matter is suppressed as much as possible.

Therefore, it has been proposed that the cooling mechanism for cooling the fuel cell stack is of a completely sealed type in which the cooling liquid continues to circulate without touching the outside air. By adopting such a completely closed cooling mechanism, it is possible to effectively prevent the entry of foreign matter into the cooling flow passage, and consequently the entry of foreign matter into the fuel cell stack.

JP 2012-18761 A

In the case of the completely closed cooling mechanism, a reserve tank for storing the cooling liquid is provided in the middle of the cooling flow path. The reserve tank is provided with an opening communicating with the inside and a lid that closes the opening. When replenishing the cooling liquid, the lid may be removed and the cooling liquid may be injected into the reserve tank. It is desirable that such a replenishment of the cooling liquid be performed by a professional operator so that foreign matter is not mixed.

However, in the related art such as Patent Document 1, the cover of the reserve tank is often exposed to the outside. Therefore, there is a high risk that the user will easily open the lid, and foreign matter will be mixed into the reserve tank and eventually the cooling flow path.

Therefore, the present specification discloses a fuel cell system that can more effectively prevent foreign matter from entering the cooling channel.

A fuel cell system disclosed in the present specification is a fuel cell system mounted on a vehicle, including an FC assembly having a fuel cell stack and a control unit for controlling the fuel cell stack, and the fuel cell stack. And a cooling mechanism for cooling using a completely closed cooling flow path, and a reserve tank provided in the middle of the cooling flow path and adjacent to the FC assembly for storing a cooling liquid, A reserve tank having an opening communicating with the opening and a lid closing the opening, and a design cover for covering the FC assembly and the lid of the reserve tank from above.

Since the design cover covers not only the FC assembly but also the lid of the reserve tank, it is difficult to access the lid, and the user is prevented from opening the lid unnecessarily. And thereby, it is possible to effectively prevent foreign matter from entering the cooling channel.

Further, the design cover has an upper surface portion that covers the FC assembly and the reserve tank from above, and a peripheral wall portion that extends downward from a peripheral edge of the upper surface portion, and is adjacent to the lid body of the peripheral wall portion. The lower end height of the portion may be lower than the lower end height of the lid.

With such a configuration, it is difficult to access the lid body not only from above but also from the lateral direction, so that it is possible to more effectively prevent erroneous opening of the lid body and, consequently, mixing of foreign matter into the cooling flow path.

Further, a scale indicating the water level of the cooling liquid is provided on the peripheral surface of the reserve tank, and the lower end height of a portion of the peripheral wall portion adjacent to the scale is higher than the upper end height of the scale. Good.

With such a configuration, the scale can be visually recognized in the state where the design cover is attached, and the necessity of replenishing the cooling liquid can be determined.

According to the fuel cell system disclosed in this specification, it is possible to more effectively prevent foreign matter from entering the cooling channel.

It is a schematic plan view of a fuel cell system. It is a schematic side view of a fuel cell system. It is an end view in the AA line of FIG. It is a block diagram which shows the structure of a cooling mechanism. It is a front view of the reserve tank periphery.

Hereinafter, the configuration of the fuel cell system 10 will be described with reference to the drawings. FIG. 1 is a schematic plan view of the fuel cell system 10, and FIG. 2 is a side view. 3 is an end view taken along the line AA of FIG. 1, and FIG. 4 is a block diagram of the cooling mechanism 30 incorporated in the fuel cell system 10. 1 and 2, only the main parts are shown and various pipes, the electric valve 48, the pump, etc. are omitted. Further, in FIG. 1, the design cover 60 is shown by a chain double-dashed line, and the members visible below the design cover 60 are shown by a solid line. Further, in the following drawings, “Fr”, “W”, and “Up” indicate the front, the width direction, and the upper side of the vehicle, respectively.

The fuel cell system 10 can be mounted on a vehicle and used as a power source for supplying electric power to a traveling electric motor or the like. As shown in FIGS. 1 to 3, a fuel cell system 10 includes a fuel cell stack (hereinafter abbreviated as “FC stack”) 12, a control unit 14, a design cover 60, and a cooling mechanism for cooling the FC stack 12. 30 are provided.

The FC stack 12 has a plurality of fuel cell cells that generate electric power by utilizing an electrochemical reaction between hydrogen and oxygen. The plurality of cells are stacked in the vehicle front-rear direction and sandwiched by the pair of end plates. A polymer electrolyte fuel cell can be used as the fuel cell. The type of fuel cell is not limited to this, and may be a phosphoric acid fuel cell, a molten carbonate fuel cell, or the like.

The FC stack 12 is housed in a stack case 16 (see FIG. 3) and fixed to the vehicle via a base member 20. At this time, the FC stack 12 is fixed in a state of inclining backward. This is for efficiently flowing the liquid flowing in the FC stack 12. That is, the FC stack 12 is provided with the cooling flow path 32 through which the cooling liquid flows and the gas flow path through which the fuel gas and the oxidizing gas flow. In this example, the FC stack 12 is inclined rearward and downward so that the cooling liquid and the water smoothly flow through the cooling flow path 32 and the gas flow path and are discharged to the outside of the FC stack 12. The water existing in the gas flow path is water that is added to humidify the fuel gas or the oxidizing gas, or water generated by power generation.

A control unit 14 that controls electric power and current generated by the FC stack 12 is installed on the FC stack 12. In this example, as shown in FIG. 3, the stack case 16 has a two-tiered structure, with the FC stack 12 on the lower side and the control unit 14 on the upper side. Hereinafter, the FC stack 12 and the control unit 14 which are integrated and unitized by the stack case 16 are collectively referred to as an FC assembly 18.

The cooling mechanism 30 cools the FC stack 12 by supplying a cooling liquid to the FC stack 12. In this example, as the cooling mechanism 30, a so-called completely sealed cooling mechanism 30 in which the cooling liquid does not come into contact with the outside air is adopted. As the cooling liquid, in order to prevent freezing at a low temperature, for example, a mixed solution of ethylene glycol and water, that is, a so-called antifreezing liquid can be used.

As shown in FIG. 4, this cooling mechanism 30 has a cooling flow path 32 through which a cooling liquid flows, and a radiator 38, a water pump 42, etc. are provided in the cooling flow path 32. The cooling flow passage 32 includes a main flow passage 34, which is an annular flow passage for returning the cooling liquid flowing out of the FC stack 12 to the FC stack 12 again through the radiator 38, and a bypass flow passage branched from the main flow passage 34. 36a-36c and the communication flow path 37 which connects the radiator 38 and the reserve tank 50 are included.

The radiator 38 is a heat exchanger that cools the cooling liquid discharged from the FC stack 12 by heat exchange with the outside air. Behind the radiator 38, a radiator fan 40 for promoting heat exchange is provided. The water pump 42 is provided in the middle of the main flow path 34 and pumps the cooling liquid. An ion exchanger 46 that adsorbs and removes ions from the cooling liquid is provided in one bypass flow passage 36a. An intercooler 44 that exchanges heat between the cooling liquid and the air supplied to the FC stack 12 is provided in the other bypass flow passage 36b. The electric valve 48 is provided at a branch point between the main flow path 34 and the bypass flow path 36a, and adjusts a flow rate ratio between the cooling liquid passing through the radiator 38 and the cooling liquid passing through the bypass passage.

Further, a reserve tank 50 that stores a cooling liquid is also provided in the other bypass flow passage 36c. The reserve tank 50 is in communication with the radiator 38 via the communication flow path 37, and exchanges cooling liquid with the radiator 38. The reserve tank 50 is a so-called completely sealed reserve tank 50 that is completely closed without being exposed to the atmosphere. The air stored in the upper portion of the reserve tank 50 serves as a damper, so that the pressure fluctuation of the cooling liquid due to the temperature fluctuation can be absorbed.

Further, as shown in FIG. 3, the reserve tank 50 is provided with an opening 52 communicating with the inside thereof, and a cap 54 (lid) having a function of a pressure adjusting valve is attached to the opening 52. Has been. The opening 52 and the cap 54 are provided in the upper portion of the reserve tank 50.

The cap 54 is made of resin, for example, and is detachably attached to the opening 52 by means such as screwing. The cap 54 releases the water vapor in the tank to the outside when the pressure in the tank becomes high, and allows the air to flow into the tank when the pressure in the tank becomes low to keep the pressure in the tank normal.

Here, in this example, the reserve tank 50 is arranged in front of the FC assembly 18. More specifically, the reserve tank 50 is fixed to the front end surface of the stack case 16 with a fastening member such as a bolt. At this time, the upper end of the reserve tank 50 is lower than the upper end of the FC assembly 18. In this example, a design cover 60 that covers the FC assembly 18 and the reserve tank 50 from above is arranged above the FC assembly 18 and the reserve tank 50.

The design cover 60 improves the appearance by covering the FC assembly 18 and eventually the control unit 14. Further, the control unit 14 is provided with various electric components that an operator can access during maintenance, but by covering with the design cover 60, the user is prevented from making unnecessary contact with these electric components. It

The design cover 60 is detachably attached to the FC assembly 18. For example, the design cover 60 may be attached to the FC assembly 18 with a clip. Specifically, for example, the clip is projected from the upper surface of the FC assembly 18. Further, a boss protruding downward may be provided on the back surface of the design cover 60 (a surface facing the upper surface of the FC assembly 18), and a clip hole may be provided in this boss. Then, the design cover 60 may be attached to the FC assembly 18 by fitting the clip of the FC assembly 18 into the clip hole of the design cover 60. As another form, the design cover 60 may be attached to the FC assembly 18 by claw fitting, bolt fastening, or the like.

By the way, as shown in FIGS. 1 to 3, in this example, not only the FC assembly 18 but also the reserve tank 50 is covered with the design cover 60. This structure is provided to prevent the user from accidentally opening the cap 54 of the reserve tank 50. That is, as described above, in this example, the completely sealed cooling mechanism 30 is adopted. Even with this completely sealed type, it is necessary to replenish and replace the cooling liquid. The replenishment and replacement of the cooling liquid is performed by removing the cap 54 of the reserve tank 50. However, in order to prevent foreign matter from entering the cooling channel 32, it is desirable that such a replenishment and replacement of the cooling liquid (opening of the cap 54) be performed by a professional operator. In particular, the FC stack 12 adversely affects the power generation efficiency even with a small amount of foreign matter. Therefore, it is desired that the cooling mechanism 30 incorporated in the fuel cell system 10 prevent foreign matter from entering as much as possible.

Therefore, in the present example, the design cover 60 covers not only the FC assembly 18 but also the cap 54 of the reserve tank 50. With such a configuration, the user cannot access the cap 54 unless the design cover 60 is removed, and thus the accidental opening of the cap 54 can be effectively prevented. As a result, it is possible to effectively prevent foreign matter from entering the cooling channel 32.

The design cover 60 has a top surface portion 62 that covers the top surfaces of the FC assembly 18 and the reserve tank 50, and a peripheral wall portion 64 that extends downward from the peripheral edge of the top surface portion 62. As is apparent from FIG. 3, the lower end height of the portion of the peripheral wall portion 64 adjacent to the reserve tank 50 is lower than the lower end height of the cap 54. With such a configuration, not only the access to the reserve tank 50 from above but also the access from the lateral direction is obstructed. And thereby, the accidental opening of the cap 54 can be prevented more reliably.

Further, as shown in FIG. 5, a scale 56 indicating the minimum amount and the maximum amount of the cooling liquid is attached to the front surface of the reserve tank 50. The lower end height of the portion of the peripheral wall portion 64 adjacent to the reserve tank 50 is higher than the upper end height of the scale 56 (the upper end of the character string “FULL” in the illustrated example). Thus, even with the design cover 60 attached, the scale 56 can be visually recognized, and it becomes possible to determine whether or not the cooling liquid needs to be replenished.

As is clear from the above description, in this example, the design cover 60 that covers both the FC assembly 18 and the reserve tank 50 from above is provided. As a result, unnecessary access to the cap 54 is effectively prevented, and it is possible to effectively prevent the cap 54 from being erroneously opened and, consequently, foreign matter from entering the cooling flow passage 32.

Note that the configuration described here is an example, and other configurations may be appropriately changed as long as the configuration cover 60 covers both the FC assembly 18 and the reserve tank 50 from above. For example, in this example, the reserve tank 50 is arranged in front of the FC assembly 18. However, if the reserve tank 50 is adjacent to the FC assembly 18 in the horizontal direction, another portion, for example, It may be arranged to the right or left or the rear of the FC assembly 18. However, in order to suppress the upper end height of the design cover 60, the upper end height of the reserve tank 50 is preferably lower than the upper end height of the FC assembly 18.

Further, in the above description, the peripheral wall portion 64 extending downward is provided on the design cover 60, but the peripheral wall portion 64 may be omitted. The fuel cell system 10 is arranged in a power unit room (corresponding to an engine room in an engine vehicle) or the like located in front of the vehicle. In this case, the fuel cell system 10 is located below the line of sight of a user who stands up and works. .. Therefore, if at least the upper part of the reserve tank 50 is covered with the design cover 60, it becomes difficult to visually recognize the cap 54 without the peripheral wall portion 64, and unnecessary access to the cap 54 can be prevented.

10 fuel cell system, 12 FC stack, 14 control unit, 16 stack case, 18 FC assembly, 20 base member, 30 cooling mechanism, 32 cooling flow path, 38 radiator, 40 radiator fan, 42 water pump, 44 intercooler, 46 Ion exchanger, 48 electric valve, 50 reserve tank, 52 opening, 54 cap, 56 scale, 60 design cover, 62 top surface part, 64 peripheral wall part.

Claims (1)

A fuel cell system mounted on a vehicle,
An FC assembly having a fuel cell stack and a control unit for controlling the fuel cell stack;
A cooling mechanism for cooling the fuel cell stack using a completely sealed cooling flow path,
A reserve tank that is provided in the middle of the cooling flow path and adjacent to the FC assembly and that stores a cooling liquid, the reserve tank having an opening that communicates with the inside thereof and a lid that closes the opening. ,
A design cover for covering the FC assembly and the lid of the reserve tank from above;
A fuel cell system comprising:

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