Temperature-control housing for controlling the temperature of components of a fuel cell system

Abstract

The invention relates to a temperature-control housing (10) for controlling the temperature of components of a fuel cell system (100), comprising a housing wall (20) surrounding a housing interior (22), wherein a separation device (30) for separating water (W) from an anode exhaust gas (AAG) for recirculation as a recirculation gas (RZG) is arranged in the housing interior (22), characterised in that a part of a cooling circuit (140) for cooling system components of the fuel cell system (100) in order to control the temperature of the housing interior (22) is also arranged in the housing interior (22), wherein the separation device (30) has an anode exhaust gas inlet (32) for receiving anode exhaust gas (AAG) from an anode section (120) of a fuel cell stack (110) of the fuel cell system (100) and has a recirculation gas outlet (34) for releasing the anode exhaust gas (AAG) as recirculation gas (RZG) into an anode supply section (122) for supply to the anode section (120) of the fuel cell stack (100).

Description

[0001] Temperature control housing for temperature control of components of a fuel cell system

[0002] The present invention relates to a temperature control housing for temperature control of components of a fuel cell system, a fuel cell system with such a temperature control housing and a method for temperature control of a temperature control housing according to the present invention.

[0003] It is known that fuel cell systems have devices for controlling the temperature of individual components. In particular, it is known that individual components in such fuel cell systems reach very high temperatures, so they require cooling. It is also known that water is produced during the operation of fuel cell systems, which appears in the anode exhaust and must be separated. For this separation, the water must be separated from the anode exhaust.

[0004] A disadvantage of the known solutions is that, particularly in special operating situations such as a cold start or, in particular, a so-called frost start (starting the fuel cell system at temperatures below 0° Celsius), uneven heat distribution and / or heating can lead to undesirable cooling of the anode exhaust gas and / or icing within the separation device. This has the disadvantage that drying out can occur and / or starting may only take place under difficult conditions or even not at all. To counter this problem, known solutions aim to equip separation devices with electrical heating elements to enable heating using electrical power in cold start situations or forest start situations, thus preventing icing.

[0005] However, the known solutions are disadvantageous in that they either limit the operating range and, in particular, the possible starting conditions due to the lack of a temperature control option for the separation device. Furthermore, the known solution is disadvantageous because the use of electrical heating devices increases complexity, costs, and space requirements.

[0006] It is therefore an object of the present invention to at least partially remedy the disadvantages described above. In particular, it is an object of the present invention to enable a cold start and additional conditioning of the anode exhaust gas in a cost-effective and simple manner.

[0007] The above object is achieved by a temperature control housing having the features of claim 1, a fuel cell system having the features of claim 11, and a method having the features of claim 12. Further features and details of the invention emerge from the subclaims, the description, and the drawings. Features and details described in connection with the temperature control housing according to the invention naturally also apply in connection with the fuel cell system according to the invention and the method according to the invention, and vice versa, so that with regard to the disclosure of the individual aspects of the invention, reference is always made to each other.

[0008] According to the invention, it is proposed that a temperature control housing be used for temperature control of components of a fuel cell system. Such a temperature control housing has a housing wall that encloses a housing interior. A separation device for separating water from an anode exhaust gas for recirculation as a recirculation gas is arranged within the housing interior. A temperature control housing according to the invention is characterized in that a part of a cooling circuit for cooling system components of the fuel cell system is arranged in the housing interior for temperature control of the housing interior. The separation device is equipped with an anode exhaust gas inlet for receiving anode exhaust gas from an anode section of a fuel cell stack of the fuel cell system.Furthermore, the separation device has a recirculation gas outlet for discharging the anode exhaust gas as recirculation gas into an anode supply section for supply to the anode section of the fuel cell stack.

[0009] The core concept of the invention is to provide the separation device with an active temperature control option. However, this active temperature control option is not implemented by a separate temperature control device, as was provided, for example, in the prior art by electrical heating means. Rather, in the inventive design, the temperature control housing uses waste heat generated by other components, in this case the system components, during operation of the fuel cell system to temperature control the separation device. In order to implement this secondary use of the absorbed waste heat from system components, the temperature control housing is equipped with part of the cooling circuit in the inventive design.

[0010] The fuel cell system according to the invention is designed in particular as a PEM fuel cell system. In a PEM fuel cell system, it is necessary to dissipate the waste heat generated in an appropriately designed cooling circuit. The membrane of a PEM fuel cell begins to deteriorate at temperatures above 95°C, since sulfonic acid chains decompose at these temperatures. Therefore, the fuel cell system has cooling circuits to protect the fuel cells and all other system components from overheating. This cooling circuit then generally has higher temperatures than, for example, a cooling circuit for the battery or the power electronics. The cooling water in the cooling circuit has a maximum temperature of approximately 90°C to approximately 95°C.

[0011] In the context of the invention, system components are advantageously understood to mean all components of the fuel cell system such as the balance-of-plant components and / or the high-temperature circuit components.

[0012] A temperature control housing according to the invention now utilizes this waste heat generated by system components, in particular the waste heat from the fuel cell stack, and the fact that this waste heat is at least partially already present in a coolant within the cooling circuit. By structurally designing part of the cooling circuit within the housing interior of the temperature control housing, it is now possible to use this waste heat at least partially to temperature control the housing interior. In a first step, it is irrelevant how the heat is transferred from the part of the cooling circuit to the housing interior. This can involve simple heat transfer surfaces, but also more complex options that take over the various heat transport phenomena, in particular heat conduction and / or heat convection, for the heat transfer from the heated coolant to the housing interior.

[0013] The inventive design thus allows waste heat, which is generated very quickly in system components when a fuel cell system is started, to be absorbed by the existing and required cooling function and passed on to the temperature control housing. This waste heat is available due to the system and can be made available very quickly for temperature control, in this case heating. This means that the risk of icing within the temperature control housing and thus all components arranged within this temperature control housing can be significantly reduced. Through temperature control, i.e. in particular the heating of the temperature control housing and its housing interior, a temperature control option is provided that can essentially completely dispense with external heat input.The increased complexity, additional installation space, and resulting costs required for separate electrical heating means from the prior art can be effectively avoided in this way. In other words, it becomes possible to significantly reduce the probability of icing when using a temperature control housing according to the invention in cold start situations, and in particular in frost start situations. This is achieved without increasing complexity and, in particular, without increasing installation space and costs. It should be noted that this not only improves the functionality of the start-up process, but also further reduces the framework conditions, for example, the minimum temperature required for starting the fuel cell system.The operating window for a frost start is thus extended, whereby the flexibility of use of a fuel cell system can be further increased by a temperature control housing according to the invention.

[0014] The temperature control housing according to the invention is also understood to be an integral component that includes all components and their functions, such as, in particular, heat exchangers, separators, injectors, and containers. In this embodiment, the housing interior is also formed integrally with all other parts and components. Such a temperature control housing is preferably manufactured at least partially by 3D printing or another manufacturing process.

[0015] It can be advantageous if, in a temperature control housing according to the invention, a condensate tank is arranged in the housing interior, in fluid communication with the separation device for collecting liquid water separated from the anode exhaust gas. This means that when liquid water is separated from the gas stream of the anode exhaust gas, this water can in principle also be passed on to other components or even directly removed from the system, but collection using such a tank device is also conceivable. In this embodiment, this condensate tank is also arranged in the housing interior of the temperature control housing, so that the reduction in the risk of icing through the described temperature control option according to the invention can also be applied to the condensate tank.This means that the condensate tank itself is provided with the option of temperature control during a cold start, especially during a frost start, so that unwanted icing can be avoided with a high degree of probability.

[0016] Furthermore, it can be advantageous if a temperature control housing according to the invention is provided with a drain valve for draining liquid water separated from the anode exhaust gas. Such a drain valve can be used in combination with a condensate tank according to the previous paragraph. However, such a drain valve without a condensate tank is also conceivable in principle. The drain valve can be arranged inside the housing interior, but in specific design variants of the temperature control housing, it can also be arranged outside it. The arrangement of the drain valve inside the housing interior brings the same advantages of temperature control, so that unwanted icing during cold start or frost start situations can also be reduced for this component in the form of the drain valve.

[0017] Furthermore, it can be advantageous if, in a temperature control housing according to the invention, a partial section of the anode supply section is arranged in the housing interior. In this embodiment, i.e., in this partial section, the anode supply section is also guided through the housing interior of the temperature control housing. This means that the temperature control functionality of the part of the cooling circuit is also available for this part of the anode supply section. The anode supply section that is temperature-controlled here can be a partial section that contains exclusively externally supplied fuel. However, the part of the anode supply section within the housing interior can also be arranged downstream of a mixing device with the recirculation gas, so that a mixing chamber for mixing fuel and recirculation gas to form a common mixed gas as the anode supply gas can also be placed within the housing space.The temperature control option according to the invention is extended here to regular operation, so that preheating of externally supplied fuel can also be ensured as part of the temperature control functionality within a temperature control housing according to the invention. In the best case, this leads to the elimination of a separate heat exchanger for preheating fuel. In such a case, the advantages of reduced installation space, reduced complexity, and minimization of costs are further enhanced.

[0018] It is further advantageous if, in a temperature control housing according to the invention, the housing interior is free of a heat exchanger. This applies in particular if, as explained in the previous paragraph, part of the anode supply section is integrated into the housing interior. According to this definition, the heat exchanger is a device in which fluid flows actively and in a guided manner in heat exchange with another fluid. This can be, for example, plate heat exchangers or similar types of heat exchanger, as will be briefly explained later. The temperature control functionality according to the invention in the non-specific manner, namely in such a way that the entire housing interior of the temperature control housing is heated, means that such specific heat exchangers can be dispensed with in this embodiment.

[0019] Further advantages are achieved if, in a temperature control housing according to the invention, a heat exchanger for heating recirculation gas and / or anode feed gas is arranged in the housing interior. Depending on the actual amount of waste heat generated by the system components of the fuel cell system, it can be calculated in advance whether the temperature control functionality is sufficient to ensure the desired preheating of recirculation gas, fuel, or mixed gas as the anode feed gas. If this temperature control function is not sufficiently dimensioned, additional heat exchangers can be used to provide specific, stronger heating for the individual gas streams. Because these heat exchangers are now also integrated into the housing interior, they no longer have to provide complete heating, but rather build on the basic temperature control provided by the temperature control housing.

[0020] It is also advantageous if, in a temperature control housing according to the invention, an ejector device of the anode supply section is at least partially arranged in the housing interior. Such an ejector device is preferably arranged entirely or substantially entirely within the housing interior. An ejector device can, for example, have a mixing chamber which can ensure mixing of fuel and recirculation gas. The mixed gas is then passed through the nozzle of the ejector device, so that a pressure difference leads to a suction effect on the recirculation gas. This means that the conveyance of the mixed gas as anode supply gas to the anode section of the fuel cell stack can preferably be carried out free of rotating components, such as fans.The integration of the ejector device within this housing interior leads to the aforementioned advantages, namely very rapid pre-temperature adjustment in cold or frost-start situations. The risk of icing, which also exists in the ejector device in known fuel cell systems, can thus be avoided with a high degree of probability.

[0021] It is also advantageous if, in a temperature control housing according to the invention, the housing wall has fluid lines that at least partially form the part of the cooling circuit in the housing interior. While, in principle, any form of heat transfer to the interior volume of the housing interior is sufficient to provide the temperature control functionality in accordance with the invention, such cooling lines can allow for a significantly more precise temperature control function. The cooling lines can, for example, be integrated into the housing wall in a network-like manner and, in particular, provide different levels of heat transfer in different areas of the housing wall.For example, it is conceivable that a very large number of cooling lines are provided in the area of ​​the separator device in order to actually make a disproportionately large amount of the waste heat conveyed within the coolant in the cooling circuit available to the separator device. Integrating the fluid lines into the housing wall further reduces the space requirement and can thus further enhance the advantage of improved installation space.

[0022] It is also advantageous if, in a temperature control housing according to the invention, the housing wall has at least one insulating section for thermally insulating the housing interior from the surroundings of the temperature control housing. Such thermal insulation can be designed, for example, as a thermal insulation layer. It serves, for example, as an outer wall layer to thermally insulate the housing wall from the outside, thus preventing both heat loss in cold external conditions and heat penetration in particularly hot ambient conditions. This further facilitates temperature control, as the temperature control system is less dependent on the ambient temperature.

[0023] Furthermore, it can be advantageous if, in a temperature control housing according to the invention, the part of the cooling circuit has control means, in particular in the form of at least one control valve, for controlling the fluid flow through the part of the cooling circuit in the housing interior in order to control the temperature control performance. This means that the volume flow and the temperature of the coolant within the cooling circuit determine the temperature control performance. The higher the temperature, the lower the volume flow can be selected in order to reduce the likelihood of icing. In order to provide a control option, control valves can be used which either completely shut off or completely open the fluid flow through this part of the cooling circuit in a qualitative manner.Quantitative control, for example by actually setting and regulating a volume flow of cooling fluid through this part of the cooling circuit, is also conceivable in principle.

[0024] Furthermore, it is an object of the present invention to provide a fuel cell system comprising a fuel cell stack with an anode section and a cathode section. The anode section is equipped with an anode supply section for supplying anode supply gas and an anode discharge section for discharging anode exhaust gas. The cathode section is equipped with a cathode supply section for supplying cathode supply gas and a cathode discharge section for discharging cathode exhaust gas. Furthermore, the fuel cell system has a cooling circuit for cooling system components of the fuel cell system. Such a fuel cell system is characterized in that a separation device for separating water from the anode exhaust gas is arranged in the anode discharge section within a temperature control housing according to the invention.Thus, a fuel cell system according to the invention also offers the same advantages as those explained in detail with reference to a temperature control housing according to the invention. The present invention further provides a method for controlling the temperature of a temperature control housing according to the present invention during a cold start of a fuel cell system according to the invention, comprising the following steps:

[0025] Starting the operation of the fuel cell system,

[0026] Operating a cooling circuit to absorb waste heat from system components of the fuel cell system,

[0027] Leading at least part of the absorbed waste heat into the part of the cooling circuit within the housing interior for delivery to the separation device.

[0028] A method according to the invention also brings with it the same advantages as have been explained in detail with reference to a temperature control housing according to the invention.

[0029] Further advantages, features, and details of the invention will become apparent from the following description, in which exemplary embodiments of the invention are described in detail with reference to the drawings. They show schematically:

[0030] Fig. 1 shows an embodiment of a fuel cell system according to the invention,

[0031] Fig. 2 shows a further embodiment of a fuel cell system according to the invention,

[0032] Fig. 3 shows a further embodiment of a fuel cell system according to the invention,

[0033] Fig. 4 shows a further embodiment of a fuel cell system according to the invention,

[0034] Fig. 5 shows a further embodiment of a fuel cell system according to the invention. Figure 1 schematically shows a fuel cell system 100 which is capable of generating electrical current from fuel and ambient air with the oxygen it contains. To ensure this, a plurality of fuel cells are arranged in a fuel cell stack 110, which can be schematically divided into an anode section 120 and a cathode section 130. Ambient air is sucked in here by a fan device and made available to the cathode section 130 as cathode feed gas KZG via a cathode feed section 132. As anode feed gas AZG, a fuel (not shown in detail) is supplied from the left as anode feed gas AZG via the anode feed section 122 to the anode section 120.After the anode feed gas AZG and the cathode feed gas KZG have been converted at the corresponding membranes of the fuel cells in the fuel cell stack 110, the resulting cathode exhaust gas KAG can be collected via the cathode discharge section 134, removed, and released, for example, to the environment. The anode exhaust gas AAG is collected here via the anode discharge section 124 and, in this embodiment, at least partially recirculated.

[0035] In order to provide recirculation of the anode exhaust gas AAG as recirculation gas RZG, the separation of liquid water W is desired here. To ensure this, the anode exhaust gas AAG is fed to a separation device 30, which is capable of separating liquid water W from the anode exhaust gas AAG and discharging it there via a discharge valve 50. The dried anode exhaust gas AAG is discharged as recirculation gas RZG from the separation device 30 via the recirculation gas outlet 34 and fed to a mixing section in the anode feed section 122. In this mixing section, the recirculation gas RZG is mixed with a fuel (not shown in detail) to form a mixed gas, which is then in turn fed as anode feed gas AZG to the anode section 120 via the anode feed section 122.

[0036] As can be seen from Figure 1, at least the separation device 30 with the recirculation gas outlet 34 and the anode exhaust gas inlet 32 ​​is arranged within a housing interior 22 of a temperature control housing 10 and is thus essentially enclosed by the housing wall 20. This means that a defined temperature can be set within this temperature control housing 10, i.e., temperature control can take place. In order to be able to actively influence this temperature control, a partial section of a cooling circuit 140 is shown here. Not shown in detail is the known part of this cooling circuit 140, which leads to the individual operating components of the fuel cell system 100 (also not shown) in order to cool them by absorbing waste heat from such system components.The coolant of the cooling circuit 140, heated in this way, is then guided into this subsection within the housing interior 22 of the temperature control housing 10, where it can release at least a portion of the absorbed waste heat. This leads to heating of the housing interior 10 and, thus, all components within this housing interior 22. This leads to the aforementioned advantages, in particular, targeted temperature control of the separation device 30 during a cold start or a frost start.

[0037] Figure 2 shows a further development of the embodiment of Figure 1. In this embodiment, the part of the cooling circuit 140 that is part of the housing interior 22 is now integrated into the housing wall 20 as a fluid line 24. This leads to greater compactness and, at the same time, even better heat distribution when controlling the temperature of the housing interior 22. As an alternative to the variant of Figure 1, a condensate tank 40 is provided here instead of a drain valve 50, which can receive and store separated water W from the separation device 30.

[0038] In Figure 3, this condensate tank 40 of Figure 2 is now combined with the drain valve 52 of Figure 1, so that the condensate tank 40 can ensure temporary storage, so to speak, and the liquid water W can be drained at certain times. Not shown in detail but also fundamentally possible is the provision of a so-called purge valve on the top side of the separation device 30 in order to also provide purge processes.

[0039] In the embodiment of Figure 3, the mixing device for mixing a recirculation gas RZG with a fuel is now also integrated into the housing interior 22. This means that not only the recirculation gas RZG, but also the supplied fuel and subsequently the generated mixed gas as anode feed gas AZG can be influenced and thus preheated by the temperature control functionality of the temperature control housing 10. In the embodiment of Figure 3, this temperature control and preheating option is so extensive that a separate heat exchanger 60 can be completely dispensed with.

[0040] Figure 4 shows a variant that requires greater preheating than can be provided by the temperature control function of the temperature control housing 10. Therefore, a heat exchanger 60 is integrated into the anode supply section 122 in the housing interior 22, which can preheat the supplied fuel before it is mixed with the recirculation gas RZG.

[0041] Figure 5 shows a variant in which the insulation from the environment is reinforced. To achieve this, the temperature control housing 10 and the housing wall 20 are designed with an insulating section 26, which ensures thermal insulation from the environment. The introduction of heat in hot ambient situations as well as the loss of heat in cold ambient situations can be significantly reduced in this way. The control options for the temperature control process itself are increased in this way. Furthermore, Figure 5 shows a variant in which the fluid flow through the cooling circuit 140 can be controlled. Here, a total of three control means 80 in the form of control valves are shown, which allow the volume flow of the coolant and thus the amount of heat introduced for the temperature control function to be controlled qualitatively or even quantitatively.In one case, a complete bypass is even possible, so that the temperature control function can not only be varied but also completely switched off by these control means 80.

[0042] Furthermore, Figures 4 and 5 show the use of a so-called ejector device 70, which is partially arranged in the housing interior 22. This ejector device 70 serves to mix the supplied fuel and recirculation gas (RZG) and to pass them through an ejector nozzle. This ejector functionality creates pressure differences that lead to the suction and thus active conveyance of the recirculation gas (RZG). This form of conveyance is preferred because no mechanically moving, particularly rotating, components are required for conveying the recirculation gas (RZG).

[0043] The above explanation of the embodiments describes the present invention exclusively by way of examples. List of reference symbols

[0044] 10 temperature control housings

[0045] 20 Housing wall

[0046] 22 Housing interior

[0047] 24 Fluid line

[0048] 26 Insulation section

[0049] 30 Separator

[0050] 32 Anode exhaust inlet

[0051] 34 Recirculation gas outlet

[0052] 40 Condensate tank

[0053] 50 drain valve

[0054] 60 heat exchangers

[0055] 70 Ejector device

[0056] 80 control agents

[0057] 100 fuel cell system

[0058] 110 fuel cell stacks

[0059] 120 anode section

[0060] 122 Anode feed section

[0061] 124 Anode discharge section

[0062] 130 Cathode section

[0063] 132 Cathode feed section

[0064] 134 Cathode discharge section

[0065] 140 Cooling circuit

[0066] AZG anode feed gas

[0067] AAG anode exhaust gas

[0068] KZG cathode feed gas

[0069] KAG cathode exhaust gas

[0070] RZG recirculation gas

[0071] W Water

Claims

Patent claims Tempering housing (10) for tempering components of a fuel cell system (100), comprising a housing wall (20) which encloses a housing interior (22), wherein a separation device (30) for separating water (W) from an anode exhaust gas (AAG) for recirculation as a recirculation gas (RZG) is arranged in the housing interior (22), characterized in that further arranged in the housing interior (22) is a part of a cooling circuit (140) for cooling system components of the fuel cell system (100) for tempering the housing interior (22),wherein the separation device (30) has an anode exhaust gas inlet (32) for receiving anode exhaust gas (AAG) from an anode section (120) of a fuel cell stack (110) of the fuel cell system (100) and a recirculation gas outlet (34) for discharging the anode exhaust gas (AAG) as recirculation gas (RZG) into an anode supply section (122) for supply to the anode section (120) of the fuel cell stack (100). The temperature control housing (10) according to claim 1, characterized in that a condensate tank (40) is arranged in the housing interior (22) in fluid communication with the separation device (30) for receiving liquid water (W) separated from the anode exhaust gas (AAG). Temperature control housing (10) according to one of the preceding claims, characterized in that a drain valve (50) for draining liquid,from the anode exhaust gas (AAG). Temperature control housing (10) according to one of the preceding claims, characterized in that a partial section of the anode supply section (122) is arranged in the housing interior (22). Temperature control housing (10) according to one of the preceding claims, characterized in that the housing interior (22) is free of a heat exchanger (60). Temperature control housing (10) according to one of claims 1 to 4, characterized in that a heat exchanger (60) for a, Heating of recirculation gas (RZG) and / or anode feed gas (AZG). Temperature control housing (10) according to one of the preceding claims, characterized in that an ejector device (70) of the anode feed section (122) is at least partially arranged in the housing interior (22). Temperature control housing (10) according to one of the preceding claims, characterized in that the housing wall (20) has fluid lines (24) which at least partially form the part of the cooling circuit (140) in the housing interior (22). Temperature control housing (10) according to one of the preceding claims, characterized in that the housing wall (20) has at least one insulating section (26) for thermally insulating the housing interior (22) from the environment of the temperature control housing (10).Temperature control housing (10) according to one of the preceding claims, characterized in that the part of the cooling circuit (140) has control means (80), in particular in the form of at least one control valve, for controlling the fluid flow through the part of the cooling circuit (140) in the housing interior (22) for controlling the temperature control performance.A fuel cell system (100) comprising a fuel cell stack (110) with an anode section (120) with an anode supply section (122) for supplying anode supply gas (AZG) and an anode discharge section (124) for discharging anode exhaust gas (AAG), further comprising a cathode section (130) with a cathode supply section (132) for supplying cathode supply gas (KZG) and a cathode discharge section (134) for discharging cathode exhaust gas (KAG), further comprising a cooling circuit (140) for cooling system components of the fuel cell system (100), characterized in that in the anode discharge section (124) a separation device (30) for separating water (W) from the anode exhaust gas (AAG) is arranged within a temperature control housing (10) having the features of one of claims 1 to 10. Method for tempering a tempering housing (10) having the features of one of claims 1 to 10 during a cold start of a fuel cell system (100) having the features of claim 11, comprising the following steps: - starting the operation of the fuel cell system (100), - operating a cooling circuit (140) for absorbing waste heat from system components of the fuel cell system (100), - guiding at least part of the absorbed waste heat into the part of the cooling circuit (140) within the housing interior (22) for delivery to the separation device (30).

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