Cooling system having single cooling circuit and highly adjustable pressure equalization device for two fuel cell systems, and method for adjusting coolant pressure

Abstract

The invention discloses a cooling system with a single cooling circuit and a highly adjustable pressure equalization device for two fuel cell systems and a method of adjusting coolant pressure. Specifically, a cooling system (1) for at least two fuel cell systems (100, 200), the cooling system (1) comprising a single cooling circuit (10) for the fuel cell systems (100, 200) and a pressure equalization device (20) for the coolant of the cooling circuit (10), wherein the pressure equalization device (20) is adapted to be connected to a discharge opening (110) of a single fuel cell system of the fuel cell systems (100, 200) to increase the pressure of the coolant.

Description

Technical Field

[0001] The present disclosure generally relates to fuel cells. In a particular aspect, the present disclosure relates to a cooling system for a fuel cell system, wherein the cooling system includes a pressure equalization device. The present invention can be applied, for example, to fuel cell systems for heavy vehicles such as trucks, buses and construction equipment, as well as other types of vehicles. Background Art

[0002] Fuel cell systems are usually cooled by a coolant within a certain pressure range to avoid internal high pressure differences between the coolant, cathode gas and anode gas. High pressure differences may cause damage, performance loss or leakage. Prior art solutions have various disadvantages, such as complex, bulky and expensive designs that require active control and regular maintenance. Summary of the invention

[0003] According to a first aspect of the present disclosure, a cooling system for at least two fuel cell systems is provided, the cooling system comprising a single cooling circuit for the fuel cell system and a pressure equalizing device for the coolant in the cooling circuit, wherein the pressure equalizing device is suitable for being connected to an exhaust port of a single fuel cell system in the fuel cell system to increase the pressure of the coolant.

[0004] A first aspect of the present disclosure may seek to solve the problem of providing a compact, efficient, reliable and cost-effective solution involving fewer components. Technical benefits of the present disclosure may include that a single cooling system requires less space than providing separate cooling systems for the first fuel cell system and the second fuel cell system. Further, since only one of the fuel cell system exhaust ports is connected to the pressure equalization device, assembly may be simplified. Providing at least two fuel cell systems instead of one fuel cell system may be advantageous for reliability or uptime.

[0005] Typically, by the connection between the exhaust port of the fuel cell system and the pressure equalization device, the coolant pressure will be adapted to the exhaust pressure of the fuel cell system. Thus, the pressure difference between the coolant and other fluids (usually air and fuel) inside the fuel cell can be reduced. The reduced pressure difference may be beneficial to fuel cell efficiency and reliability, and in particular to lifespan.

[0006] Optionally, in some examples, including at least one preferred example, the cooling system includes a height adjustment component for adjusting the height of the pressure equalization device. Thus, the pressure of the cooling circuit can be adjusted in a simple manner. For example, the pressure of the cooling circuit can be adjusted to adapt to the respective coolant pressure requirements of both the first fuel cell system and the second fuel cell system. The coolant pressure can, for example, be adjusted to a pressure level between the corresponding pressure requirements of the first fuel cell system and the second fuel cell system. In addition, the pressure of the coolant is adjusted by adjusting the height of the pressure equalization device, and the pressure equalization device does not have to be a type including a coolant membrane or the like.

[0007] Optionally, in some examples, including at least one preferred example, the height adjustment assembly is manual.Such a solution may be particularly cost-effective, easy to use and implement.

[0008] Optionally, in some examples, including at least one preferred example, the height adjustment assembly is configured to allow the pressure equalization device to be positioned at a number of different vertical positions. This solution may be particularly advantageous for usability, for example, because a service technician or workshop personnel can easily position the pressure equalization device at a certain height. The cooling system may be configured to provide instructions or signals associated with the appropriate vertical position. For example, the cooling system may cooperate with a separate vehicle control unit for providing the instructions.

[0009] Optionally, in some examples, including at least one preferred example, the height adjustment assembly includes a number of vertically spaced supports that allow the pressure equalization device to be manually positioned at a corresponding number of different discrete vertical positions. Such a design may be cost effective and easy to use.

[0010] Optionally, in some examples, including at least one preferred example, the height adjustment assembly comprises a guide rail having supports in the form of slots or protrusions adapted to hold the pressure equalization device. This design can provide a relatively simple design of the supports and the pressure equalization device.

[0011] Optionally, in some examples, including at least one preferred example, the number of discrete different vertical positions is 3, 4, or 5, with a reasonable range being between 3 and 10. Fewer positions may be advantageous for usability and simplicity of structural design, while a greater number of positions may be advantageous for more precise adjustment of coolant pressure.

[0012] Optionally, in some examples, including in at least one preferred example, the pressure equalization device is positioned at the same or higher vertical height as the fuel cell system. Positioning the pressure equalization device at the same vertical height as the fuel cell system may result in the pressure equalization device not additionally increasing the pressure of the coolant due to gravity, which may be desirable in some cases. As will be appreciated, when the pressure equalization device is vertically positioned higher than the fuel cell system, the potential energy of the vertically elevated coolant of the pressure equalization device results in an increased coolant pressure within the fuel cell system. In most cases, it may be beneficial to position the pressure equalization device higher than the fuel cell system because this helps or enables the coolant pressure to be adjusted to the relatively higher pressure of other fluids present inside the fuel cell.

[0013] Optionally, in some examples, including in at least one preferred example, the cooling system comprises or is connected to a control unit capable of identifying respective coolant pressure requirements of respective fuel cell systems.As mentioned, the cooling system may be connected, for example, to a vehicle control unit.

[0014] Optionally, in some examples, including in at least one preferred example, the control unit is configured to output a signal indicating a suitable height position for the pressure equalization device based on the respective coolant pressure requirement. The pressure equalization device can then be positioned at a height position, for example by workshop personnel, so that the coolant pressure is appropriately adjusted.

[0015] According to a second aspect of the present disclosure, there is provided a multi-fuel cell system including a first fuel cell system, a second fuel cell system and the above-mentioned cooling system.

[0016] According to a third aspect of the present disclosure, a vehicle comprising at least two fuel cell systems and the above-mentioned cooling system is provided. In other words, the vehicle may include a multi-fuel cell system. Optionally, the vehicle is a heavy-duty vehicle, such as a truck or a bus. The fuel cell system may be particularly useful for heavy-duty vehicles to meet the energy needs of the vehicle, because pure battery electric heavy-duty vehicles often require very large and heavy high-voltage batteries. Typically, a heavy-duty vehicle according to the present invention includes a fuel cell system and a high-voltage battery.

[0017] According to a fourth aspect of the present disclosure, there is provided a method for regulating the coolant pressure of a single cooling circuit for a first fuel cell system and a second fuel cell system, wherein the cooling circuit is connected to an exhaust port of the first fuel cell system but not to an exhaust port of the second fuel cell system, the method comprising operating the fuel cell system and continuously regulating the coolant pressure through a cooling circuit connected to an exhaust port of the first fuel cell system. In other words, the pressure of the exhaust port affects the pressure of the coolant in the cooling circuit. The cooling circuit may alternatively be connected to an exhaust port of the second fuel cell system but not to an exhaust port of the first fuel cell system.

[0018] Optionally, in some examples, including in at least one preferred example, a pressure equalization device is connected to the cooling circuit, and the method includes adjusting the coolant pressure by adjusting the height of the pressure equalization device.

[0019] Optionally, in some examples, including at least one preferred example, adjusting the coolant pressure by adjusting the height of the pressure equalization device includes adjusting the coolant pressure based on respective coolant pressure requirements of the first fuel cell system and the second fuel cell system.

[0020] Optionally, in some examples, including at least one preferred example, adjusting the coolant pressure by adjusting the height of the pressure equalization device includes adjusting or setting the coolant pressure to a pressure between the coolant pressure requirement of the first fuel cell system and the coolant pressure requirement of the second fuel cell system. Thus, in this way, the coolant pressure can be adjusted to a pressure suitable for both the first fuel cell system and the second fuel cell system.

[0021] Optionally, in some examples, including at least one preferred example, adjusting the coolant pressure by adjusting the height of the pressure equalization device includes manually adjusting the height of the pressure equalization device.

[0022] Optionally, in some examples, including at least one preferred example, adjusting the coolant pressure by adjusting the height of the pressure equalization device includes positioning the pressure equalization device in one of a number of discrete height positions.

[0023] Optionally, in some examples, including at least one preferred example, the method includes obtaining respective coolant pressure requirements of the first fuel cell system and the second fuel cell system from a control unit, and adjusting the coolant pressure based thereon by adjusting the height of the pressure equalization device.

[0024] Further possible measures of the method and the associated advantages correspond to those mentioned in connection with the cooling system. The method can be performed in connection with the cooling system described herein, ie also in connection with a multi-fuel cell system and a vehicle. The method can be computer-implemented.

[0025] Those skilled in the art will appreciate that the disclosed aspects, examples (including any preferred examples), and / or the accompanying claims may be appropriately combined with each other. Additional features and advantages are disclosed in the following description, claims, and drawings, and in part will be apparent to those skilled in the art or recognized by practicing the disclosure as described herein. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Examples are described in more detail below with reference to the accompanying drawings.

[0027] Figure 1 is an exemplary system diagram of a cooling system for at least two fuel cell systems according to an example.

[0028] Figure 2 is a flow chart of an exemplary method of regulating coolant pressure of a single cooling circuit for a first fuel cell system and a second fuel cell system according to an example. DETAILED DESCRIPTION

[0029] The detailed description set forth below provides information and examples of the disclosed technology in sufficient detail to enable those skilled in the art to practice the disclosure.

[0030] Figure 1 A cooling system 1 for at least two fuel cell systems 100, 200 is shown. Herein, the fuel cell systems 100, 200 are only schematically depicted and are not illustrated or described in detail because the present disclosure mainly relates to the cooling thereof. As shown, the cooling system 1 includes a single cooling circuit 10 for the fuel cell systems 100, 200. In other words, the same cooling circuit 1 is connected to the two fuel cell systems 100, 200. More precisely, the fuel cell systems 100, 200 are connected in parallel. The cooling circuit 10 is shown to pass through the fuel cell systems 100, 200 to transfer heat through a heat exchanger schematically shown. Typically, the cooling circuit 10 passes through the undepicted fuel cell stacks of the fuel cell systems 100, 200 to remove or supply heat. The cooling system 1 may include a pump, a radiator, and a fan, such as Figure 1 A three-way valve and a bypass line can also be provided to completely or partially bypass the radiator, e.g. during preheating, see Figure 1 Typically, coolant pressure is regulated by adjusting the pump speed.

[0031] exist Figure 1In the drawings, solid lines (eg, 10) represent coolant flow lines or cooling circuits. Dashed lines represent cathode supply and cathode exhaust lines, or more generally air flow lines, and dashed lines represent communications, such as wired or wireless communications.

[0032] As shown, the cooling system 1 comprises a pressure equalizing device 20 for the coolant of the cooling circuit 10. Thus, a single pressure equalizing device 20 may be provided. As shown, the pressure equalizing device 20 is adapted to be connected to the exhaust port 110 of a single one of the fuel cell systems 100, 200 to increase the pressure of the coolant. Both fuel cell systems 100, 200 comprise exhaust ports 110, 210, but only one of these exhaust ports is connected to the pressure equalizing device 20.

[0033] Still reference Figure 1 The cooling system includes a height adjustment assembly 30 for adjusting the height of the pressure equalization device 20. The height adjustment assembly 30 is manual, which means that the height of the pressure equalization device 20 is manually adjustable. For example, the height adjustment assembly 30 can be configured so that a workshop person can grasp the pressure equalization device 20 by hand and move it up or down.

[0034] As indicated, the height adjustment assembly 30 is configured to allow the pressure equalization device 20 to be positioned in a number of different vertical positions indicated as 31, 32, and 33. The height adjustment assembly 30 may be configured so that workshop personnel may manually grasp the pressure equalization device 20 and move it from one vertical position to another.

[0035] The height adjustment assembly 30 includes a certain number of vertically spaced supports 31, 32, 33..., which allow the pressure equalization device 20 to be manually positioned at a corresponding number of different discrete vertical positions. In the present example, the height adjustment assembly 30 includes a guide rail 35 having supports 31, 32, 33 in the form of slots or protrusions, which are suitable for holding the pressure equalization device 20. Typically, the height adjustment assembly 30 is configured to hold the pressure equalization device 20 in a form-fitting manner. For example, the supports 31, 32, 33 can engage undepicted support receivers on the pressure equalization device 20. Therefore, the pressure equalization device 20 can be securely attached to the guide rail 35 via the supports 31, 32, 33. Reference Figure 1, there may be a first rail and a second rail 35, in the present example, at least one of which includes a number of protruding supports 31, 32, 33 to cooperate with support receivers. In other examples, the pressure equalization device 20 may include protrusions and the rail 35 may include corresponding receivers. The pressure equalization device 20 may be adapted to be positioned between the first rail and the second rail 35. The pressure equalization device 20 and the rail 35 may be configured such that the pressure equalization device 20 may be fixed in a form-fitting manner in a selected discrete vertical position of different discrete vertical positions 31, 32, 33.

[0036] exist Figure 1 In the embodiment, the pressure equalization device 20 is positioned in the highest position, and three possible lower positions are available. Therefore, the number of discrete different vertical positions can be four. In other examples, there may be three or five discrete different vertical positions. A suitable range of discrete different vertical positions is three to ten.

[0037] In the lowest position, the pressure equalizing device 20 may be positioned at the same vertical height as the fuel cell system 100, 200. Typically, in positions other than the lowest position, the pressure equalizing device 20 is positioned vertically higher than the fuel cell system 100, 200.

[0038] Figure 1 A control unit 50 is schematically shown, which is capable of identifying the respective coolant pressure requirements of the respective fuel cell systems 100, 200. The dashed line shows that the control unit 50 can communicate directly with the first fuel cell system 100 and the second fuel cell system 200. The control unit 50 is configured to output a signal indicating a suitable height position for the pressure equalization device 20 based on the respective coolant pressure requirements. By way of example only, the first fuel cell system 100 may need to be at a certain first coolant pressure, or operate close to its optimal condition. At the same time, the second fuel cell system 200 may need to be at a certain second coolant pressure that is higher than the first coolant pressure, or operate close to its optimal condition. In this case, the pressure equalization device 20 can be positioned at a height that causes the coolant pressure to be between the first coolant pressure and the second coolant pressure (e.g., approximately equal to the average pressure of the first coolant pressure and the second coolant pressure).

[0039] refer to Figure 1 The first fuel cell system 100 and the second fuel cell system 200 may be collectively referred to as a multi-fuel cell system 300. The first fuel cell system 100 and the second fuel cell system 200 and the cooling system 1 may be arranged in a vehicle 400 (typically a heavy vehicle).

[0040] As already mentioned, the fuel cell systems 100, 200 typically each include a fuel cell stack, not depicted. These fuel cell stacks typically include bipolar plates, electrical connections, inputs and outputs for cathode gas (typically air) and anode gas (such as hydrogen). Bipolar plates can be particularly susceptible to damage due to inadequate coolant pressure regulation. In Figure 1 In the figure, the dotted lines show the cathode gas flow to and from the fuel cell systems 100 and 200. On the left, the cathode gas (in this case, ambient air) enters the corresponding air inlet of the fuel cell systems 100 and 200. The air filter is arranged downstream of the corresponding air inlet. In an embodiment not depicted, the two fuel cell systems 100 and 200 may include a common air inlet. Next, the air passes through the corresponding blower or compressor, then passes through the corresponding optional air supply cooler and enters the corresponding fuel cell system 100 and 200. Inside the fuel cell system 100 and 200, the air reacts with the fuel to generate electrical energy for, for example, propelling a heavy vehicle 400. The air then leaves the fuel cell system 100 and 200 through the first fuel cell system first exhaust port 110 and the second fuel cell system first exhaust port 210, respectively. As shown, the first turbine and the second turbine can be arranged to collect energy from the first fuel cell system exhaust port 110 and the second fuel cell system exhaust port 210. The first exhaust port 110 is connected to the pressure equalization device 20. More precisely, the air flow line extends from between the first exhaust port 110 and the first turbine to the pressure equalization device 20. In a non-depicted embodiment, the second exhaust port 210 may alternatively be connected to the pressure equalization device 20. There may be a non-depicted coolant line connecting the supply air cooler to the cooling circuit 10.

[0041] Likewise, the pressure equalizing device 20 is adapted to be connected to the exhaust port 110 of a single fuel cell system in the fuel cell systems 100, 200 to increase the pressure of the coolant. More specifically, the coolant pressure is regulated by connecting the pressure equalizing device 20 to the exhaust port 110. Figure 1 As shown, the pressure equalization device 20 may include a first port (here, an upper port) for connection to the exhaust port 110 and a second port (here, a lower port) for connection to the cooling circuit 10. The first port may be referred to as a cathode gas port, and the second port may be referred to as a coolant port. Typically, the upper portion of the pressure equalization device 20 contains cathode gas, and the lower portion of the pressure equalization device 20 contains coolant, which is typically a liquid. The coolant level is Figure 1 . A separator or membrane is also shown that separates the coolant from the cathode gas. The membrane can be liquid-tight or fluid-tight. In an embodiment not depicted, the coolant membrane can be omitted so that the coolant is in contact with the cathode gas.

[0042] Next reference Figure 2 A method 500 for regulating the coolant pressure of a single cooling circuit 10 for a first fuel cell system 100 and a second fuel cell system 200 is described. The method can be applied, for example, to the fuel cell systems 100, 200 and cooling system 1 described herein, and for simplified understanding, the method is also referred to as Figure 1 Therefore, the cooling circuit 10 is connected to the exhaust port 110 of the first fuel cell system 100 , but is not connected to the exhaust port 210 of the second fuel cell system 200 .

[0043] The method 500 includes operating 510 a first fuel cell system 100 and a second fuel cell system 200 while continuously regulating 520 a coolant pressure via a cooling circuit 10 connected to an exhaust port 110 of the first fuel cell system 100. Typically, although not described in detail herein, the coolant pressure is additionally regulated by regulating a speed of a coolant pump.

[0044] As already described, the pressure equalizing device 20 is connected to the cooling circuit 10, and the method 500 may therefore include adjusting 540 the coolant pressure by adjusting the height of the pressure equalizing device 20. Thus, the coolant pressure may be adjusted in three separate ways: a first way is by the speed of the coolant pump, a second way is by connecting the drain port 110, and a third way is by the height of the pressure equalizing device 20 being adjusted. The adjustment of the coolant pressure by connecting the drain port 110 and by the coolant pump speed may be referred to as automatic or continuous coolant pressure adjustment 520. The adjustment of the coolant pressure by adjusting the height of the pressure equalizing device 20 may be referred to as manual, discontinuous or intermittent coolant pressure adjustment 540.

[0045] As already described, adjusting 540 the coolant pressure by adjusting the height of the pressure equalizing device 20 may include adjusting the coolant pressure based on the respective coolant pressure requirements of the first fuel cell system 100 and the second fuel cell system 200. In more detail, adjusting 540 the coolant pressure by adjusting the height of the pressure equalizing device 20 may include adjusting or setting the coolant pressure to between the coolant pressure requirement of the first fuel cell system 100 and the coolant pressure requirement of the second fuel cell system 200.

[0046] As already described, adjusting 540 the coolant pressure by adjusting the height of the pressure equalization device 20 may include manually adjusting the height of the pressure equalization device 20. Adjusting 540 the coolant pressure by adjusting the height of the pressure equalization device 20 may include positioning the pressure equalization device 20 in one of a number of discrete height positions.

[0047] Reference again Figure 1 , the method may further include: obtaining 530 the respective coolant pressure requirements of the first fuel cell system and the second fuel cell system 100, 200 from the control unit 50, and adjusting 540 the coolant pressure based on this by adjusting the height of the pressure equalization device 20. The different coolant pressure requirements of the first fuel cell system 100 and the second fuel cell system 200 may be caused by changes in performance and / or health status. Generally, the coolant pressure requirements of the fuel cell system may increase with the load. Higher loads lead to higher discharge pressures, and therefore, according to the present invention, lead to higher coolant pressures (because of the pressure equalization device 20 connected to the discharge port 110). Now, the first fuel cell system 100 can have a first pressure channel, which means an acceptable lower coolant pressure and a higher coolant pressure for each load point. Similarly, the second fuel cell system 200 can have a second pressure channel, which can be different from the first pressure channel, for example due to changes in health status between the fuel cell systems 100, 200. By adjusting the height of the pressure equalization device 20, the coolant pressure can be adjusted to be within the first pressure channel and the second pressure channel.

[0048] Examples are also disclosed under the following terms: 1. A cooling system (1) for at least two fuel cell systems (100, 200), the cooling system (1) comprising: - a single cooling circuit (10) for the fuel cell system (100, 200), and - a pressure equalizing device (20) for the coolant of the cooling circuit (10), wherein the pressure equalizing device (20) is adapted to be connected to an exhaust port (110) of a single fuel cell system of the fuel cell systems (100, 200) to increase the pressure of the coolant.

[0049] 2. The cooling system (1) according to clause 1, comprising a height adjustment assembly (30) for adjusting the height of the pressure equalization device (20).

[0050] 3. A cooling system (1) as described in clause 2, wherein the height adjustment assembly (30) is manual.

[0051] 4. The cooling system (1) of clause 2 or 3, wherein the height adjustment assembly (30) is configured to allow the pressure equalization device (20) to be positioned at a number of different vertical positions.

[0052] 5. A cooling system (1) as described in claim 4, wherein the height adjustment assembly (30) includes a certain number of vertically spaced supports (31, 32, 33...), and the certain number of vertically spaced supports allow the pressure equalization device (20) to be manually positioned at a corresponding number of different discrete vertical positions.

[0053] 6. A cooling system (1) as described in clause 5, wherein the height adjustment assembly (30) comprises a guide rail (35) having support members (31, 32, 33...) in the form of slots or protrusions, the support members (31, 32, 33...) being suitable for holding the pressure equalization device (20).

[0054] 7. The cooling system (1) according to any of clauses 4 to 6, wherein the number of discrete different vertical positions is between 3 and 10.

[0055] 8. The cooling system (1) according to any of clauses 4 to 6, wherein the number of discrete different vertical positions is 3, 4 or 5.

[0056] 9. The cooling system (1) according to any preceding clause, wherein the pressure equalization device (20) is positioned at the same vertical height as or higher than the fuel cell system (100, 200).

[0057] 10. A cooling system (1) as claimed in any preceding clause, comprising or being connected to a control unit (50) capable of identifying the respective coolant pressure requirements of the respective fuel cell systems (100, 200).

[0058] 11. The cooling system (1) according to clause 10, wherein the control unit (50) is configured to output a signal indicating a suitable height position for the pressure equalization device (20) based on the respective coolant pressure requirement.

[0059] 12. A multi-fuel cell system (300), comprising a first fuel cell system (100), a second fuel cell system (200) and a cooling system (1) as described in any one of the preceding clauses.

[0060] 13. A vehicle (400) comprising at least two fuel cell systems (100, 200) and a cooling system (1) according to any one of clauses 1 to 11.

[0061] 14. A method (500) for regulating coolant pressure of a single cooling circuit (10) for a first fuel cell system and a second fuel cell system (100, 200), wherein the cooling circuit (10) is connected to an exhaust port (110) of the first fuel cell system (100) but not to an exhaust port (210) of the second fuel cell system (200), the method (500) comprising: - operating (510) the fuel cell system (100, 200), and - continuously regulating (520) the coolant pressure via the cooling circuit (10) connected to the outlet (110) of the first fuel cell system (100).

[0062] 15. The method (500) of clause 14, wherein the pressure equalization device (20) is connected to the cooling circuit (10), and the method (500) comprises adjusting (540) the coolant pressure by adjusting the height of the pressure equalization device (20).

[0063] 16. A method (500) as described in clause 15, wherein adjusting (540) the coolant pressure by adjusting the height of the pressure equalization device (20) includes adjusting the coolant pressure based on the respective coolant pressure requirements of the first fuel cell system and the second fuel cell system (100, 200).

[0064] 17. A method (500) as described in clause 16, wherein the coolant pressure is adjusted (540) by adjusting the height of the pressure equalization device (20) to set the coolant pressure between the coolant pressure requirement of the first fuel cell system (100) and the coolant pressure requirement of the second fuel cell system (200).

[0065] 18. The method (500) of any one of clauses 15 to 17, wherein adjusting (540) the coolant pressure by adjusting the height of the pressure equalizing device (20) comprises manually adjusting the height of the pressure equalizing device (20).

[0066] 19. A method (500) as described in any of clauses 15 to 18, wherein adjusting (540) the coolant pressure by adjusting the height of the pressure equalization device (20) includes positioning the pressure equalization device (20) in one of a number of discrete height positions.

[0067] 20. A method (500) as described in any of clauses 14 to 19, comprising obtaining (530) the respective coolant pressure requirements of the first fuel cell system and the second fuel cell system (100, 200) from a control unit (50), and adjusting (540) the coolant pressure based on this by adjusting the height of the pressure equalization device (20).

[0068] The terms used herein are only for the purpose of describing specific aspects and are not intended to limit the present disclosure. As used herein, unless the context clearly indicates otherwise, the singular forms "a", "an" and "the" are intended to include the plural forms as well. As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items. It should also be understood that the term "comprises / comprising / includes and / or including" when used herein indicates the presence of stated features, integers, actions, steps, operations, elements and / or parts, but does not exclude the presence or addition of one or more other features, integers, actions, steps, operations, elements, parts and / or their groups.

[0069] It should be understood that although the terms first, second, etc. may be used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another element. For example, without departing from the scope of the present disclosure, a first element may be referred to as a second element, and similarly, a second element may be referred to as a first element.

[0070] Relative terms such as "below" or "above" or "upper" or "lower" or "horizontal" or "vertical" may be used herein to describe the relationship of one element to another element, as shown in the figures. It should be understood that these terms and those discussed above are intended to cover different device orientations in addition to the orientations depicted in the figures. It will be understood that when an element is referred to as being "connected" or "coupled" to another element, the element may be directly connected or directly coupled to the other element, or there may be intervening elements. In contrast, when an element is referred to as being "directly connected" or "directly coupled" to another element, there are no intervening elements.

[0071] Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by those of ordinary skill in the art to which the present disclosure belongs. It should also be understood that, unless otherwise clearly defined herein, the terms used herein should be interpreted as meanings consistent with their meanings in the context of this specification and the relevant art, and should not be interpreted in an idealized or overly formal sense.

[0072] It should be understood that the present disclosure is not limited to the aspects described above and shown in the accompanying drawings; rather, the skilled person will recognize that many changes and modifications may be made within the scope of the present disclosure and the appended claims. In the drawings and description, various aspects have been disclosed for illustrative purposes only and not for limiting purposes, and the scope of the disclosure is set forth in the appended claims.

Claims

1. A cooling system (1) for at least two fuel cell systems (100, 200), the cooling system (1) comprising - a single cooling circuit (10) for the fuel cell system (100, 200), and - a pressure equalizing device (20) for the coolant of the cooling circuit (10), wherein the pressure equalizing device (20) is adapted to be connected to an exhaust port (110) of a single fuel cell system of the fuel cell systems (100, 200) to increase the pressure of the coolant.

2. The cooling system (1) according to claim 1, comprising a height adjustment assembly (30) for adjusting the height of the pressure equalization device (20).

3. The cooling system (1) of claim 2, wherein the height adjustment assembly (30) is manual.

4. The cooling system (1) of claim 2 or 3, wherein the height adjustment assembly (30) is configured to allow the pressure equalization device (20) to be positioned at a number of different vertical positions.

5. A cooling system (1) as claimed in claim 4, wherein the height adjustment assembly (30) includes a certain number of vertically spaced supports (31, 32, 33...), and the certain number of vertically spaced supports allow the pressure equalization device (20) to be manually positioned at a corresponding number of different discrete vertical positions.

6. A cooling system (1) according to claim 5, wherein the height adjustment assembly (30) comprises a guide rail (35) having supports (31, 32, 33...) in the form of slots or protrusions, the supports (31, 32, 33...) being suitable for holding the pressure equalization device (20).

7. The cooling system (1) according to any one of claims 4 to 6, wherein the number of discrete different vertical positions is between 3 and 10.

8. The cooling system (1) according to any one of claims 4 to 6, wherein the number of discrete different vertical positions is 3, 4 or 5 positions.

9. The cooling system (1) according to any of the preceding claims, wherein the pressure equalization device (20) is positioned at the same vertical height as or above the fuel cell system (100, 200).

10. A cooling system (1) according to any preceding claim, comprising or being connected to a control unit (50) which is able to identify the respective coolant pressure requirements of the respective fuel cell systems (100, 200).

11. The cooling system (1) of claim 10, wherein the control unit (50) is configured to output a signal indicating a suitable height position for the pressure equalization device (20) based on the respective coolant pressure requirement.

12. A multi-fuel cell system (300) comprising a first fuel cell system (100), a second fuel cell system (200) and a cooling system (1) according to any one of the preceding claims.

13. A vehicle (400) comprising at least two fuel cell systems (100, 200) and a cooling system (1) according to any one of claims 1 to 11.

14. A method (500) for regulating coolant pressure of a single cooling circuit (10) for a first fuel cell system and a second fuel cell system (100, 200), wherein the cooling circuit (10) is connected to an exhaust port (110) of the first fuel cell system (100) but is not connected to an exhaust port (210) of the second fuel cell system (200), the method (500) comprising: - operating (510) the fuel cell system (100, 200), and - continuously regulating (520) the coolant pressure via the cooling circuit (10) connected to the outlet (110) of the first fuel cell system (100).

15. The method (500) of claim 14, wherein the pressure equalization device (20) is connected to the cooling circuit (10), and the method (500) comprises adjusting (540) the coolant pressure by adjusting the height of the pressure equalization device (20).

16. A method (500) as claimed in claim 15, wherein adjusting (540) the coolant pressure by adjusting the height of the pressure equalization device (20) includes adjusting the coolant pressure based on the respective coolant pressure requirements of the first fuel cell system and the second fuel cell system (100, 200).

17. A method (500) as claimed in claim 16, wherein the coolant pressure is adjusted (540) by adjusting the height of the pressure equalization device (20) to set the coolant pressure between the coolant pressure requirement of the first fuel cell system (100) and the coolant pressure requirement of the second fuel cell system (200).

18. The method (500) of any one of claims 15 to 17, wherein adjusting (540) the coolant pressure by adjusting the height of the pressure equalization device (20) comprises manually adjusting the height of the pressure equalization device (20).

19. The method (500) of any one of claims 15 to 18, wherein adjusting (540) the coolant pressure by adjusting the height of the pressure equalization device (20) comprises positioning the pressure equalization device (20) in one of a number of discrete height positions.

20. A method (500) as claimed in any one of claims 11 to 14, comprising obtaining (530) the respective coolant pressure requirements of the first fuel cell system and the second fuel cell system (100, 200) from a control unit (50), and adjusting (540) the coolant pressure based on this by adjusting the height of the pressure equalization device (20).

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