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CN-122029647-A - Fuel cell system and method for operating a fuel cell system

CN122029647ACN 122029647 ACN122029647 ACN 122029647ACN-122029647-A

Abstract

The invention relates to a fuel cell system having an anode circuit in which a water separator (3) and a recirculation fan (8) are arranged. In order to make the operation of the fuel cell system simpler and more efficient without increasing the costs for manufacturing the fuel cell system, the recirculation fan (8) is arranged with a defined geodetic height (45) relative to the water separator (3) and is connected in a water-conducting manner with the water separator (3) such that separated water enters the recirculation fan (8) from the water separator (3) as a function of the water level (41, 42, 43) in the water separator (3).

Inventors

  • T. Falkenault
  • T. Bosch

Assignees

  • 罗伯特·博世有限公司

Dates

Publication Date
20260512
Application Date
20240904
Priority Date
20231013

Claims (10)

  1. 1. A fuel cell system (1) having an anode circuit (6) in which a water separator (3) and a recirculation fan (8) are arranged, characterized in that the recirculation fan (8) is arranged with a defined geodetic height (45) relative to the water separator (3) and is connected in a water-conducting manner with the water separator (3) such that separated water enters the recirculation fan (8) from the water separator (3) as a function of the water level (41, 42, 43) in the water separator (3).
  2. 2. Fuel cell system according to claim 1, characterized in that at least one fluid connection (36, 37) is provided between the recirculation fan (8) and the water separator (3), through which fluid connection water enters the recirculation fan (8) from the water separator (3) as a function of the water level (41, 42, 43) in the water separator (3).
  3. 3. The fuel cell system according to claim 2, characterized in that the fluid connection (36, 37) is embodied as a hole.
  4. 4. A fuel cell system according to claim 2 or 3, characterized in that the fluid connection (36, 37) is embodied and arranged such that, depending on the water level (41, 42, 43) in the water separator (3), water is sucked into the recirculation fan (8), accelerated in the recirculation fan (8) and conveyed through the recirculation fan (8).
  5. 5. The fuel cell system according to any one of the preceding claims, characterized in that the water separator (3) is arranged adjacent to the recirculation fan (8) at the defined geodetic height (45).
  6. 6. Method for operating a fuel cell system (1) according to any of the preceding claims, having a galvanic pile (2) to which anode gas with fuel is supplied on the anode side in the anode circuit (6), which fuel reacts with an oxidizing agent in the galvanic pile (2), wherein water contained in anode exhaust gas led out of the galvanic pile (2) is separated and collected by means of the water separator (3), wherein the fuel contained in the anode exhaust gas is supplied again to the fuel cell galvanic pile (2) in the form of a recirculating exhaust gas (40) via the recirculating fan (8), characterized in that the recirculating gas (40) and the recirculating fan (8) itself are tempered in the recirculating fan (8) using water from the water separator (3).
  7. 7. The method according to claim 6, characterized in that the recirculated gas (40) is humidified in the recirculation fan (8) using water from the water separator (3).
  8. 8. Method according to claim 6 or 7, characterized in that water from the water separator (3) is fed to the recirculation fan (8) in an accurate metering.
  9. 9. Method according to any one of claims 6 to 8, characterized in that the water level (41, 42, 43) in the water separator (3) is regulated in connection with the use of water from the water separator (3) in the recirculation fan (8) by means of a level sensor (36) in the water separator (3).
  10. 10. A computer program arranged to perform all the steps of the method according to any of claims 6 to 9.

Description

Fuel cell system and method for operating a fuel cell system Technical Field The invention relates to a fuel cell system having an anode circuit in which a water separator and a recirculation fan are arranged. The invention also relates to a method for operating such a fuel cell system. Background German publication DE 10 2021 203 349 A1 discloses a method for operating a fuel cell system, in which method hydrogen gas is supplied to a fuel cell stack as anode gas and the anode gas discharged from the fuel cell stack is recirculated, and water contained in the anode gas is separated by means of a water separator, is collected in a container and is removed from the fuel cell system by opening a drain valve, wherein for adjusting the drain valve the time period required for completely draining the container is taken and the filling time period is set as a function of the determined drain time period, with the proviso that the point in time at which the drain starts is known and the point in time at which the drain ends is determined by evaluating the voltage of the fuel cell stack. German publication DE 10 2022 200 298 A1 discloses a method for operating a fuel cell system, in which method hydrogen is supplied to the anodes of a fuel cell stack via an anode circuit and recirculated, wherein the recirculation is effected by means of a blower integrated into the anode circuit, wherein the blower is driven by a turbine which is integrated into the hydrogen path connecting the anode circuit with a hydrogen high-pressure tank, so that the hydrogen extracted from the high-pressure tank drives the turbine. Disclosure of Invention The object of the invention is to make the operation of a fuel cell system simpler and more efficient without increasing the costs for manufacturing the fuel cell system. In a fuel cell system having an anode circuit in which a water separator and a recirculation fan are arranged, the task is solved in that the recirculation fan is arranged at a defined geodetic height relative to the water separator and is connected to the water separator in a water-conducting manner such that separated water passes from the water separator into the recirculation fan as a function of the water level in the water separator. The stack includes a plurality of fuel cells. Accordingly, the stack is also referred to as a fuel cell stack in german. The fuel is, for example, hydrogen. The anode gas contains at least one further gaseous component, such as nitrogen, in addition to the fuel, in particular hydrogen. Nitrogen is an inert gas which is also used in particular to test fuel cell systems prior to start-up. In addition to nitrogen, the anode gas contains unavoidable impurities as necessary. The oxidizing agent is, for example, oxygen, which is contained in air, which is preferably supplied to the stack in compressed form. The claimed fuel cell system is preferably a cryogenic fuel cell system with liquid product water. The recirculation in the anode circuit is preferably effected by means of a gas delivery unit, such as a fan or jet pump. Jet pumps are also referred to by the english term "jet pump". The jet pump works according to the venturi principle. The fuel cell system may include a jet pump and a fan. By means of the water-conducting connection between the water separator and the recirculation fan, a water overflow is formed, so that water overflows from the water separator into the recirculation fan once a predetermined water level in the water separator has been exceeded. The fuel cell system may include a plurality of water separators. The claimed water overflow is then advantageously associated with a main water separator. The recirculation fan is preferably actively driven, for example by means of an electric motor. A preferred embodiment of the fuel cell system is characterized in that at least one fluid connection is provided between the recirculation fan and the water separator, through which fluid connection water is led from the water separator into the recirculation fan, depending on the water level in the water separator. The at least one fluid connection may be configured as a pipeline. The at least one fluid connection may also comprise at least one through hole. In addition to the at least one fluid connection for water, at least one further fluid connection for anode gas is advantageously provided, by means of which, after separation of the water, the anode gas enters from the water separator into the recirculation fan. From there, the dehydrated and tempered, optionally additionally humidified anode off-gas is then supplied again as recycle gas to the stack. In order to keep the path between the water separator and the recirculation fan, in particular for the water, short, the water separator and the recirculation fan are preferably arranged very close to each other in space. The water separator and the recirculation fan can also advantageously be combined in a common structural unit.