WO2017186376A1

WO2017186376A1 - Cooling device for a fuel cell and fuel cell system comprising the cooling device

Info

Publication number: WO2017186376A1
Application number: PCT/EP2017/054202
Authority: WO
Inventors: Helerson Kemmer; Arpad Imre; Christian Mielke; Johannes Schild
Original assignee: Robert Bosch Gmbh
Priority date: 2016-04-27
Filing date: 2017-02-23
Publication date: 2017-11-02
Also published as: DE102016207164A1

Abstract

The invention relates to a cooling device (1a; 1b), in particular for cooling a fuel cell (110), having a cooling medium line (10) for conducting cooling medium through a cooling unit (40) of the cooling device (1a; 1b), and a first operating medium line (20) for conducting a first operating medium through a first operating unit (50) of the cooling device (1a; 1b), wherein the cooling unit (40) is designed to cool the first operating unit (50), wherein the cooling medium line (10) is fluidically connected to the first operating medium line (20) downstream of the cooling unit (40). The invention further relates to a fuel cell system (100a; 100b) comprising a cooling device (1a; 1b) according to the invention, wherein the first operating unit (50) is an operating unit of the fuel cell system (100a; 100b). The invention further relates to a method for cooling a fuel cell (110) by using a cooling device (1a; 1b) according to the invention, wherein a first operating medium is led from the first operating medium line (20) to the cooling medium line (10).

Description

description

title

Cooling device for a fuel cell and fuel cell system with the

cooler

The present invention relates to a cooling device, in particular for a fuel cell, comprising a coolant line for conducting coolant through a cooling unit of the cooling device and a resource line for conducting a resource through an operating unit of the cooling device, wherein the cooling unit is configured for cooling the operating unit. The present invention further relates to a fuel cell system with the

Cooler.

State of the art

Not only motor vehicles such as cars and trucks benefit from emission-free mobility through fuel cell systems, but so-called off-highway vehicles such as construction machinery, municipal and airport vehicles. For example, airport operators are increasingly turning to alternative solutions to reduce emissions and noise

Drives and in the future with fuel cell systems to a new

Environmentally friendly future technology for mobile machines,

Vehicles on the apron and fleets. The advantages of vehicles with fuel cell drive over, for example, the classic

Accumulator technology is its long range and fast fueling in just minutes.

For safe operation of fuel cell systems, FCCUs (Fuel Cell Control Units) are known, which control all components of a fuel cell system for efficient interaction. An FCCU controls that Fuel cell system with integrated hydrogen, air and fuel

Coolant regulation. A fuel cell system with the FCCU has a

Cooling device, by which a fuel cell stack can be cooled by a coolant. More specifically, in such a cooling device, the cathode of the fuel cell stack may be cooled by a cooling unit through which coolant is passed.

Since hydrogen from the fuel cell stack may diffuse into the coolant, the coolant line must be open to the environment. this will

achieved for example by a discharge opening in a coolant reservoir. The space in which the cooling system is degassed must be protected from hydrogen accumulation. This can be done by a

Relief opening against the gravitational direction or a mechanical ventilation can be realized. The relief opening causes as a side effect that the coolant is in front of a coolant pump to ambient pressure level.

During the operation of a fuel cell stack, certain gas pressure levels in the anode (hydrogen) and the cathode (air) are specifically set. The pressure of the fuel cell stack flowing through

Coolant may only have a certain maximum deviation to the pressure level of the hydrogen and to the pressure level of the air, for example a maximum of ± 1 bar. The deviation is dictated by the design used inter alia by the seals used and ensures the tightness in areas at the anode, the cathode and a cooling device in the fuel cell stack.

In order to achieve the desired pressure level, although ambient pressure prevails in the expansion tank, a sufficiently large-sized coolant pump, or a plurality of coolant pumps, as well as a throttle downstream of the fuel cell stack, the pressure level on

Fuel cell stack outlet above that of the surge tank

(Ambient pressure) stops to be used. The coolant pump should be monitored for failure or insufficient power to prevent excessive flow

Pressure deviation to the anode to recognize timely and counteract this accordingly. Disclosure of the invention

In the present case, a cooling device for cooling a

Fuel cell system and a fuel cell system with this

Cooling device according to the claims provided. As a result, an improved cooling device and a fuel cell system with the cooling device are provided by means of which a fuel cell can be cooled at low cost. In addition, a method is provided by which a fuel cell with low

Energy consumption can be cooled. In this case, features and details that are described in connection with the cooling device, of course, also in connection with the fuel cell system according to the invention and in each case vice versa, so with respect to the disclosure of the individual aspects of the invention always reciprocal reference is or may be. According to a first aspect of the present invention, a

Cooling device, in particular a cooling device for cooling a

Fuel cell, provided. The cooling device has a coolant line for conducting coolant through a cooling unit of the cooling device.

In addition, the cooling device has a first operating line for conducting a first operating means through a first operating unit of the cooling device. The cooling unit is designed here for cooling the first operating unit. The coolant line is downstream of the cooling unit in fluid communication with the first resource line. That is, a refrigerant degassing port of the refrigerant piping is not led directly to the environment, but into the pressurized first service piping.

Characterized in that the coolant line downstream of the cooling unit in

Fluid connection with the first resource line is, the level of the refrigerant pressure at least in sections, in particular downstream of a coolant pump of the cooling device, always equal to a pressure in the first Resource line, ie, the first resource pressure. The coolant pressure downstream of the cooling unit, in particular at an output of the

Cooling device, thus without use of a throttle or the like to a desired value, for example, 1.5 bar, are held. Moreover, in the present cooling device, the use of a large coolant pump or a plurality of coolant pumps can be dispensed with. As a result, both costs for the pump (s) and costs for the energy consumption of a large coolant pump or more

Saved coolant pumps.

The present cooling device is in particular for the cooling of a

Fuel cell stack or a fuel cell of a fuel cell system designed. However, the present invention is not limited thereto. Thus, the cooling device can also be designed for cooling of other applications with coolant-based cooling.

Under the coolant is to be understood in particular a coolant fluid. The coolant line is correspondingly preferred for conducting the coolant as a hose or pipe or hose or piping system

designed. The coolant line is preferably part of a closed coolant circuit of the cooling device. The cooling unit can also be called

Section of the coolant line to be configured, which is preferably arranged in the vicinity or at the first operating unit. The first operating unit is preferably designed as an operating unit for the operation of the fuel cell. The first operating unit is designed, for example, as a cathode or has a cathode.

The first operating means is to be understood in particular as an operating fluid, which is preferably air or at least has. The first

Betriebsmittelleitung is to conduct the first resource according preferably as a hose or pipe or hose or

Piping system designed.

The fluid connection between the coolant line downstream of the cooling unit and the first resource line is for example by a hose or Pipe made. That is, a hose or pipe section of the

Coolant line downstream of the cooling unit is connected directly to a hose or pipe section of the first service line.

According to one embodiment of the present invention, it is possible that in a cooling device, the first operating unit has a cathode and the operating medium line is designed as a cathode gas line. The cathode here is in particular a cathode of a fuel cell, wherein the

Fuel cell further comprises an anode, which may be referred to as a second operating unit. In the cathode gas line usually ambient air is sucked in, which in the context of the present invention, this oxygen-containing gas mixture or the ambient air can be referred to as cathode gas. In known cooling devices for fuel cells, it is possible that hydrogen from the fuel cell in the cooling unit or the coolant line penetrates.

For example, according to a development of the present invention, it is possible for the coolant line to be located downstream of the cooling unit in FIG

Fluid communication with the first resource line upstream of the first operating unit is. This makes it possible that particles of the coolant can be filtered by the operating unit. In the specific case of a cooling device, which is used for cooling a fuel cell, thereby hydrogen must not be conducted into the environment, but can be performed in the designed as a first operating unit cathode and passed through this in the environment. At the cathode, the hydrogen can be harmlessly oxidized or oxidized. In order to avoid that coolant enters the first operating unit or a fuel cell, downstream of the cooling unit between the latter and the first operating unit, for example in a corresponding connecting line, a membrane of the cooling device is arranged, which is, for example, hydrogen and air permeable, but impermeable for larger molecules such as glycol or molecules of a liquid.

In the context of the present invention, it may be of further advantage if, in the case of a cooling device, the coolant line is located downstream of the cooling unit in FIG Fluid communication with the first resource line downstream of the first operating unit is. This can be reliably prevented

Coolant in the first operating unit, or when cooling a fuel cell, penetrates into this. This could lead to damage of the fuel cell due to the possibly contained in the coolant moisture or chemical components of the coolant such as glycol. In this case, further, the cost of a membrane as described above could be saved. Moreover, it is possible according to the present invention, that in a

Cooling device, a coolant expansion tank is connected to the coolant line and the coolant expansion tank spatially in

Gravity direction is lower than a junction of the fluid connection between the coolant line and the first resource line downstream of the first operating unit is arranged. Since, in the case of a cooling device, which is in use for cooling a fuel, the cathode gas is usually discharged counter to the direction of gravity upwards, this is structurally simple and inexpensive to implement. In such a

Configuration of the cooling device, it is also possible that hydrogen through the first resource line and a cathode gas line reliably to the

Environment can be delivered.

It may be further advantage according to the present invention, when in a cooling device, a coolant expansion tank is connected to the coolant line and the coolant expansion tank spatially in

Gravity direction is higher than the first operating unit is arranged. In the case of a cooling device, which is used for cooling a fuel cell, thereby an overflow of hydrogen into the first operating unit or a cathode can be ensured. More specifically, for each falling pressure change, for example, when switching off the cathode, for example, 1.5 bar to 1 bar, in the course of pressure equalization, for example, one third of an air space in the coolant expansion tank, in particular the top third, in which the hydrogen accumulates to be sucked back into the cathode. With a rising pressure change can

then fresh air is again pressed into the coolant expansion tank become. It is a further advantage if the coolant expansion tank is arranged spatially higher in the direction of gravity than the cooling unit. As a result, devices or mechanisms can be avoided, which would prevent leakage of the coolant expansion tank.

Moreover, it is possible according to the invention for a sensor to be located in or on the first operating line to detect a substance that differs from the operating medium. The sensor is preferred as

Hydrogen sensor designed. This makes it possible to identify hydrogen, which may not be filtered by the first operating unit, and to initiate necessary countermeasures. The sensor is preferably positioned downstream of the first operating unit.

It may be of further advantage, if in an inventive

Cooling device, the cooling unit to the first operating unit, in particular directly to the first operating unit, is arranged. This allows the

Operating unit to be cooled particularly efficiently. The cooling device can thereby also be arranged particularly space-saving in a fuel cell system. As already mentioned above, the cooling unit in the sense of the present invention can also be designed as a section of the coolant line which, in particular, rests directly against the first operating unit or

is arranged.

According to another aspect of the present invention is a

Fuel cell system provided with a cooling device as explained above, wherein the first operating unit is an operating unit of the

Fuel cell system is. More specifically, in this case, the first operating unit is a cathode, which in turn is a cathode of a fuel cell of the fuel cell system. This brings the invention

Fuel cell system has the same advantages as detailed with

With reference to the cooling device according to the invention have been described.

According to yet another aspect of the present invention is a

A method of cooling a fuel cell with one as above

described cooling device provided. According to this method is a first resource of the first resource line to the

Coolant line led or passed. Thus, the method according to the invention also brings about the same advantages as have been described in detail with reference to the cooling device according to the invention.

Further, measures improving the invention will become apparent from the following description of some embodiments of the invention, which are shown schematically in the figures. All from the

Claims, the description or the drawing resulting features and / or advantages, including constructive details and spatial arrangements, both for themselves and in the various

Combinations essential to the invention.

Each show schematically:

1 is a block diagram of a fuel cell system with a

Cooling device according to the prior art,

Fig. 2 is a block diagram of a fuel cell system with a

Cooling device according to a first embodiment of the present invention,

Fig. 3 is a further block diagram of a fuel cell system with the

Cooling device according to the first embodiment of the present invention,

Fig. 4 is a block diagram of a fuel cell system with a

Cooling device according to a second embodiment of the present invention,

Fig. 5 is a further block diagram of a fuel cell system with the

Cooling device according to the second embodiment of the present invention, and Fig. 6 is a functional diagram of an inventive

Fuel cell system.

Elements with the same function and mode of operation are each provided with the same reference numerals in FIGS.

For a brief explanation of the prior art is in Fig. 1 a

Fuel cell system 100 shown with a cooling device 1, in which a coolant line 10 is designed as part of a cooling circuit. The cooling circuit also has a coolant pump 120 and a radiator 140.

FIG. 2 shows a fuel cell system 100a with a cooling device 1a according to a first embodiment. As can be seen from FIG. 2, the illustrated cooling device 1 a is designed for cooling a fuel cell 110. The cooling device 1a has a coolant line 10 for conducting coolant through a cooling unit 40 of the cooling device 1a. The

Coolant is according to the illustrated embodiment in a

closed coolant circuit circulates. In addition, the cooling device la to a designed as a cathode gas line first resource line 20 to

Passing a first operating means (cathode gas) through a designed as a cathode first operating unit 50 of the cooling device la. The cooling unit 40 is designed here for cooling the first operating unit 50 and thereby for cooling the fuel cell 110. As further shown in Fig. 2, the coolant line 10 is downstream of the cooling unit 40 with the first

Resource line 20 upstream of the first operating unit 50 in FIG

Fluid communication.

The fuel cell system 100a shown in FIG. 2 also has a second operating line 30 designed as an anode gas line for conducting a second operating means (anode gas) through a second operating unit 60 designed as an anode. The first operating unit 50 and the second

Operating unit 60 form according to the illustrated embodiment, the essential components of a fuel cell 110. According to the cooling device la shown in Fig. 2, a level of the refrigerant pressure before a Coolant pump 120 substantially automatically always equal to a cathode pressure and this in a defined ratio to a

Anodendruck be kept. In addition, in the cooling device la according to FIG. 2 in the first

Power line 20, a sensor 70 for detecting a different from the

Equipment of differing substance positioned. More specifically, the sensor 70 is configured as a hydrogen sensor for detecting hydrogen. Although the sensor 70 is disposed downstream of the first operating unit 50 in both FIGS. 2 and 3, the sensor 70 may be disposed upstream of the first operating unit 50.

FIG. 3 shows a block diagram of a fuel cell system 1 a with a cooling device 1 a as shown in FIG. 2 from a different perspective. The cooling device 1a shown in FIG. 3 has a coolant compensation tank 90. From the illustration of Fig. 3 it can be seen that the coolant expansion tank 90 is connected to the coolant line 10 and the

Coolant expansion tank 90 in a installed state of

Cooling device la spatially higher in the direction of gravity than the first

Operating unit 50 is arranged.

4 shows a fuel cell system 100b with a cooling device 1b according to a second embodiment. The cooling device 1b according to the second embodiment differs in particular from the

Cooling device la according to the first embodiment that the

Coolant line 10 downstream of the cooling unit 40 in fluid communication with the first resource line 20 downstream of the first operating unit 50 is.

5 shows a block diagram of a fuel cell system 1b with a cooling device 1b as shown in FIG. 4 from a different perspective. The in

Fig. 5 illustrated coolant expansion tank 90 is connected to the coolant line 10. In addition, in a built-in state of the cooling device 1b, the coolant surge tank 90 is spatially disposed in the gravity direction lower than a joint 80 of the fluid communication. The coolant expansion tank 90 is in this case between the coolant line 10 and the first resource line 20, downstream of the first

Operating unit 50 extends, arranged. In addition, the coolant expansion tank 90 is spatially higher in the direction of gravity than the first operating unit 50 and the cooling unit 40 is arranged.

With reference to FIGS. 1 to 5, a method for cooling a fuel cell 110 with a cooling device 1 a, 1 b as described above may be further understood, in which the first operating means of the first

Operating medium line 20 is guided in the direction of or to the coolant line 10. Since the coolant in a closed or gas-tight

Coolant circuit is performed or circulated, thereby the level of the refrigerant pressure can always be kept automatically or at the level of the cathode pressure. For this purpose, a controller can be provided which controls the method and monitors it by means of sensors.

6 shows a fuel cell system 100a with the cooling device 1a. Further, in Fig. 6, the coolant surge tank 90 is shown integrated in the fuel cell system 100a. The illustrated fuel cell system 100a further includes a fuel cell 110, a coolant pump 120 for pumping the

Coolant and a motor 130 for operating the cooling device la on.

Claims

claims

A cooling device (1a, 1b), in particular for cooling a fuel cell (110), comprising a coolant line (10) for conducting coolant through a cooling unit (40) of the cooling device (1a, 1b) and a first operating line (20) for conducting a first operating means by a first operating unit (50) of the cooling device (1a; 1b), the cooling unit (40) being designed to cool the first operating unit (50),

characterized,

in that the coolant line (10) is in fluid communication with the first operating line (20) downstream of the cooling unit (40).

2. Cooling device (1a, 1b) according to claim 1,

characterized,

the first operating unit (50) has a cathode and the

Operating medium line (20) is designed as a cathode gas line.

3. Cooling device (la) according to claim 1 or 2,

characterized,

in that the coolant line (10) downstream of the cooling unit (40) is in fluid communication with the first operating line (20) upstream of the first operating unit (50).

4. Cooling device (lb) according to claim 1 or 2,

characterized,

in that the coolant line (10) downstream of the cooling unit (40) is in fluid communication with the first operating line (20) downstream of the first operating unit (50). Cooling device (1b) according to claim 4,

characterized,

a coolant surge tank (90) is connected to the coolant line (10) and the coolant surge tank (90) is spatially lower in the direction of gravity than a joint (81) of the

Fluid communication between the coolant line (10) and the first resource line (20) downstream of the first operating unit (50) is arranged.

Cooling device (1a; 1b) according to one of claims 1 to 5,

characterized,

in that a coolant compensation tank (90) is connected to the coolant line (10) and the coolant compensation tank (90) is arranged spatially higher in the direction of gravity than the first operating unit (50).

Cooling device (1a, 1b) according to one of claims 1 to 6,

characterized,

in that a sensor (70) is positioned in or on the first operating line (20) for the purpose of detecting a substance which differs from the operating medium.

Cooling device (1a; 1b) according to one of claims 1 to 7,

characterized,

in that the cooling unit (40) is arranged on the first operating unit (50).

A fuel cell system (100a, 100b) having a cooling device (1a, 1b) according to any one of claims 1 to 8, wherein the first operation unit (50) is an operation unit of the fuel cell system (100a, 100b).

A method of cooling a fuel cell (110) with a cooling device (1a; 1b) according to any one of claims 1 to 8, wherein a first resource of the first resource line is led to the coolant line (10).