Fuel cell system for a mobile work machine

Abstract

The invention relates to a fuel cell system (1) for a mobile work machine, in particular an industrial truck, comprising a housing (2), a fuel cell device (11), in particular a hydrogen-powered fuel cell device (11), a cooling system (16) which comprises a fan device (15), wherein the fan device (15) is designed to generate a cooling air flow for the fuel cell device (11), and a power voltage transformer (31). The power voltage transformer (31) is cooled by the cooling air flow for the fuel cell device (4).

Description

[0001] Description

[0002] Fuel cell system for a mobile work machine

[0003] The invention relates to a fuel cell system for a mobile work machine, in particular an industrial truck, comprising a housing, a fuel cell device, in particular a hydrogen-operated fuel cell device, a cooling system comprising a fan device, the fan device being configured to generate a cooling air flow of the fuel cell device, and a power voltage converter.

[0004] In mobile work machines, in particular industrial trucks, with an electric drive system, it is known to use a fuel cell system to supply energy to the electric drive system.

[0005] Known fuel cell systems comprise a hydrogen-powered fuel cell device, to which oxygen or ambient air is supplied at a cathode region and hydrogen is supplied at an anode region. In the fuel cell device, the oxygen from the ambient air is reacted with the hydrogen, generating electrical energy and waste heat. To dissipate this waste heat from the fuel cell device, a cooling system with a fan device is provided, which generates a cooling air flow through the fuel cell device.

[0006] In addition to the hydrogen system, such a fuel cell system also consists of an electric hybrid system, which includes a battery, at least one electronic controller and / or at least one contactor, and a power-voltage converter as electrical components. The power-voltage converter serves to convert the voltage of the fuel cell device to the voltage of the battery. The power-voltage converter is designed to convert the voltage of the fuel cell device to a higher or lower voltage. Typically, the power-voltage converter converts the voltage of the fuel cell device to a lower voltage. These electrical components have efficiencies that generate corresponding waste heat during operation of the electrical components.This waste heat from the electrical components must be dissipated to the outside environment to protect the power voltage converter from overheating and / or to protect the battery of the fuel cell system from excessive heat. If the battery in the fuel cell system is a lithium-ion battery, it will begin to age rapidly at temperatures above approximately 40°C, which will impact the service life of the fuel cell system and increase service costs. Furthermore, the other electrical components, particularly the power voltage converter, must be cooled. Due to the limited space available in the fuel cell system housing, it is generally not possible to provide a complex water cooling circuit to cool the power voltage converter and, if applicable, other electrical components of the fuel cell system.

[0007] The present invention is based on the object of providing a fuel cell system for a mobile work machine, in particular an industrial truck, of the type mentioned at the outset, in which an effective and simply constructed cooling system is provided.

[0008] This object is achieved according to the invention in that the power voltage converter is cooled by the cooling air flow of the fuel cell device.

[0009] With the cooling air flow of the fuel cell device generated by the fan device, the power voltage converter, which comprises one or more DC / DC converters and generates corresponding waste heat during operation of the fuel cell system, can be cooled in a simple, cost-effective and effective manner by means of air cooling.

[0010] According to an advantageous embodiment of the invention, the cooling system has an air supply duct leading from an air inlet to the fuel cell device, and the power-voltage converter is provided with a heat sink arranged in the air supply duct. The power-voltage converter is thus cooled by the fuel cell device's air supply flowing in the air supply duct, thereby achieving simple and effective air cooling of the power-voltage converter. According to an advantageous embodiment of the invention, the air supply duct is formed in the housing of the fuel cell system. The air supply duct can be formed in the housing in a simple manner, for example, by appropriate sheet metal.

[0011] According to an advantageous embodiment of the invention, at least one electrical unit compartment is formed in the housing of the fuel cell system, in which at least one electrical component of the fuel cell system is arranged, wherein the housing is provided with at least one ventilation opening in the region of the unit compartment. As a result, cooling of the electrical unit compartment and thus of the electrical component(s) arranged in the unit compartment can be achieved in a simple, cost-effective, and effective manner through one or more ventilation openings and thus convection. The waste heat generated in the unit compartment by the electrical component(s) arranged in the unit compartment can easily diffuse outwards to the environment via the ventilation opening in the housing.

[0012] According to an advantageous embodiment of the invention, the electrical component is designed as a battery, in particular a lithium-ion battery, and / or as an electronic controller and / or as a contactor. Effective air cooling of the battery, for example, a lithium-ion battery, and / or an electronic controller and / or a contactor of the fuel cell system can be achieved in a simple manner via the ventilation openings.

[0013] According to an advantageous embodiment of the invention, the fuel cell device and the fan device are fastened to an assembly holder, wherein the assembly holder is arranged adjacent to the battery. This allows a simple thermal connection of the battery, for example a lithium-ion battery, and / or the fuel cell system to the assembly holder. With such a thermal connection of the battery to the assembly holder, the operational waste heat of the battery can be transferred to the assembly holder and thus dissipated. This makes it possible to achieve passive cooling of the battery, whereby complex active cooling of the battery, for example air cooling by means of a fan or liquid cooling, can be dispensed with. According to an advantageous embodiment of the invention, the assembly holder is designed as a cast metal component.In such a metal cast component, a large amount of heat can be released from the battery and thus dissipated.

[0014] According to an advantageous embodiment of the invention, the battery is arranged on a metal casting that holds a hydrogen tank of the fuel cell system. This allows for a simple thermal connection of the battery, for example a lithium-ion battery, to the metal casting holding the hydrogen tank. With such a thermal connection of the battery to the metal casting holding the hydrogen tank, the operational waste heat of the battery can be transferred to the metal casting and thus dissipated. This makes it possible to achieve passive cooling of the battery, which eliminates the need for complex active cooling of the battery, for example air cooling by means of a fan or liquid cooling. A large amount of heat can be released from the battery to a metal casting holding the hydrogen tank and thus dissipated.

[0015] The invention further relates to a mobile work machine, in particular an industrial truck, with an electric drive system and a fuel cell system according to the invention, wherein the fuel cell system is designed to supply the electric drive system of the work machine with electrical energy, and wherein the housing of the fuel cell system is designed to be inserted into a battery receiving space of the work machine.

[0016] In such work machines, the fuel cell system can be installed in the battery compartment of the work machine instead of a traction battery, for example, a bi-acid battery. Due to the limited space and size of the battery compartment, the fuel cell system intended as a replacement for a traction battery also requires little installation space. Due to the required limited installation space for such a fuel cell system intended as a replacement for a traction battery, the air cooling of the power-voltage converter and the electrical components according to the invention can achieve space-saving, effective, cost-effective, and simple cooling of the power-voltage converter and the electrical components of the fuel cell system.

[0017] The invention has a number of advantages.

[0018] The air cooling of the power voltage converter according to the invention by means of the supply air of the fuel cell device and the air cooling of the electrical components of the fuel cell system via ventilation openings in the housing of the fuel cell system can achieve cooling of the power voltage converter and the electrical components of the fuel cell system in a cost-effective manner.

[0019] The heat losses of the power voltage converter can be easily dissipated through the supply air for the fuel cell device, whereby the power voltage converter does not require its own cooling system (air or liquid), but uses the cooling system of the fuel cell device.

[0020] With the ventilation opening(s) in the housing, the electrical unit compartment and thus the electrical components arranged in the unit compartment can be cooled passively via convection in a simple manner and does not require an active cooling circuit, for example by means of a fan or liquid cooling, whereby an active cooling circuit would lead to higher costs and reduced availability of the fuel cell system with regard to the robustness of the electrical components.

[0021] If a thermal connection of the battery to the assembly holder, which is designed as a metal cast component and thus as a metal cast body, and / or to the metal cast body supporting the hydrogen tank is provided, the operational waste heat of the battery can be easily transferred to the large-volume metal cast body and thus dissipated. This passive cooling eliminates the need for an active cooling system for the battery, for example, by means of a fan or liquid cooling. Further advantages and details of the invention are explained in more detail with reference to the exemplary embodiment illustrated in the schematic figures.

[0022] Figure 1 is a perspective view of the fuel cell system according to the invention,

[0023] Figure 2 shows a further view of the fuel cell system according to the invention from behind,

[0024] Figure 3 shows a further side view of the fuel cell system according to the invention,

[0025] Figure 4 shows a section through Figure 1 and

[0026] Figure 5 shows an aggregate holder of the fuel cell system according to the invention in a perspective view.

[0027] Figures 1 to 3 show a fuel cell system 1 according to the invention for a mobile work machine, in particular an industrial truck, with an electric drive system which can be used as a replacement for a traction battery in a battery receiving space of the work machine.

[0028] The fuel cell system 1 has a rectangular housing 2 within which the components of the fuel cell system 1 are installed.

[0029] The housing 2 consists of a base plate, a front end wall 2a, a rear end wall 2b, a right side wall 2c, a left side wall 2d and a cover plate 2e.

[0030] Figure 4 shows a longitudinal section through the fuel cell system 1 of Figure 1 in a vertically upper area.

[0031] An electrical equipment compartment 5 is arranged within the housing 2, in which a battery 6 of the fuel cell system 1 is located. The battery 6 is preferably designed as a lithium-ion battery. A battery management system for the lithium-ion battery can also be arranged in the equipment compartment 5.

[0032] An aggregate holder 10 is arranged laterally adjacent to the battery 6 between the battery 6 and the front end wall 2a in the front upper corner area of ​​the housing 2.

[0033] The aggregate holder 10 is shown in more detail in Figure 5.

[0034] A hydrogen-powered fuel cell device 11 is attached to the assembly holder 10. For this purpose, a mounting flange 12 is formed on the top of the assembly holder 10, to which the fuel cell device 11 is attached. The fuel cell device 11 is preferably designed as a fuel cell stack. An air filter 13 can also be arranged on the top of the fuel cell device 11.

[0035] The unit holder 10 is further provided with a flange plate 14, to which a fan device 15 of a cooling system 16 of the fuel cell device 11 is attached. The fan device 15 is preferably designed as an electric fan.

[0036] The unit holder 10 forms an exhaust air duct 17 of the cooling system 16 of the fuel cell device 11 between the fuel cell device 11 and the fan device 15.

[0037] The cooling system 16 comprises the fan device 15, which generates a cooling air flow flowing through the fuel cell device 11. The fan device 15 draws cooling air into an air supply duct 21 through two cooling air inlets 20a, 20b, which are formed in the upper region of the opposite end walls 2a, 2b of the housing 2 of the fuel cell system 1. The air supply duct 21 is formed between the cover plate 2e and an upper cover hood 22 arranged on the cover plate 2e. From the air supply duct 21, the drawn-in cooling air flows through an opening in the cover plate 2e, through the air filter 13, and then through the fuel cell device 11.From the fuel cell device 11, the cooling air heated at the fuel cell device 11 enters the exhaust air duct 17 formed in the unit holder 10 and, after flowing through the fan device 15, is discharged to the environment at a cooling air outlet 18 of the unit holder 10 via ventilation openings 25 in the front end wall 2a of the housing 2.

[0038] The cooling air flow is illustrated in Figure 4 with the arrows KL.

[0039] The fan device 15 is arranged in the cooling air flow downstream of the fuel cell device 11.

[0040] The cooling air sucked in by the fan device 15, which flows to the fuel cell device 11, can further be used as process air of a cathode region of the fuel cell device 11.

[0041] A hydrogen tank (not shown in detail) is arranged vertically below the battery 6 within the housing 2. The hydrogen contained in the hydrogen tank is supplied to an anode region of the fuel cell device 11. The battery 6 is arranged on a metal cast body 50, which holds the hydrogen tank (not shown in detail) of the fuel cell system 1. Preferably, the battery 6 is thermally connected to the metal cast body 50 holding the hydrogen tank, wherein the operational waste heat of the battery 6 can be easily transferred to the large-volume metal cast body 50 holding the hydrogen tank and thus dissipated. This passive cooling eliminates the need for an active cooling system for the battery, for example by means of a fan or liquid cooling.

[0042] In the illustrated embodiment, the battery 6 is provided with a stepped shoulder 6a on which the unit holder 10 rests and against which the unit holder 10 rests.

[0043] In the illustrated embodiment, the unit holder 10 is designed as a cast metal component.

[0044] Between the battery 6 and the metal cast component

[0045] A thermal connection can be provided for the assembly holder 10. The operational waste heat of the battery 6 can thus be easily transferred to the assembly holder 10, which is designed as a cast metal component, and thus dissipated. This passive cooling eliminates the need for an active cooling system for the battery, for example, using a fan or liquid cooling.

[0046] A power-to-voltage converter 31 is arranged vertically above the battery 6 in the electrical unit compartment 5. The power-to-voltage converter 31 can comprise one or more DC / DC converters.

[0047] In the illustrated embodiment, the power-voltage converter 31 is attached to the underside of the cover plate 2e of the housing 2. The power-voltage converter 31 is further provided with a heat sink 32, which is arranged in the air intake duct 21 of the cooling system 16. For this purpose, the cover plate 2e is provided with a recess through which the heat sink 32 arranged on the power-voltage converter 31 extends upward into the air intake duct 21.

[0048] The cooling air flowing in the supply air duct 21 from the cooling air inlet 20b to the air filter 13 thus flows through the heat sink 32 of the power voltage converter 31, whereby the power voltage converter 31 can be cooled in a simple and effective manner by the cooling air flow of the cooling system 16 of the fuel cell device 11.

[0049] In the area of ​​the aggregate compartment 5, in the illustrated embodiment in the area of ​​the rear upper corner area of ​​the housing 2, ventilation openings 35 are formed in the rear end wall 2b. In addition, in the area of ​​the aggregate compartment 5 in the rear upper corner area of ​​the housing 2, ventilation openings 36 can be formed in the right side wall 2c of the housing 2 and / or ventilation openings 37 can be formed in the left side wall 2d of the housing 2.

[0050] The unit compartment 5, and thus the electrical components arranged in the unit compartment 5, can be passively cooled via convection via the ventilation openings 35, 36, and 37, respectively, whereby heat from the electrical unit compartment 5 can diffuse outward via the ventilation openings 35, 36, and 37 forming convection openings. The electrical unit compartment 5 further extends vertically within the housing 2 below the unit holder 10 into the region of the front end wall 2a. An electronic controller and / or a contactor controlling the fuel cell system 1 can be arranged in this region of the electrical unit compartment 5.

[0051] In order to achieve cooling of this area of ​​the electrical unit compartment 5 with the components arranged therein, in the illustrated embodiment in the front lower corner area of ​​the housing 2 in the right side wall 2c

[0052] Ventilation openings 40 and / or ventilation openings 41 are formed in the left side wall 2d. The area of ​​the electrical unit compartment 5 located in the front lower corner area of ​​the housing 2, and thus the electrical components located in this area of ​​the electrical unit compartment 5, can be passively cooled via convection via the ventilation openings 40 and 41, respectively, whereby heat from this area of ​​the unit compartment 5 can diffuse outward via the ventilation openings 40 and 41 forming convection openings.

Claims

Patent claims 1. Fuel cell system (1) for a mobile work machine, in particular an industrial truck, with a housing (2), with a fuel cell device (11), in particular a hydrogen-operated fuel cell device (11), with a cooling system (16) comprising a fan device (15), wherein the fan device (15) is designed to generate a cooling air flow of the fuel cell device (11), and with a power voltage converter (31), characterized in that the power voltage converter (31) is cooled by the cooling air flow of the fuel cell device (4).

2. Fuel cell system according to claim 1, characterized in that the cooling system (16) has an air supply duct (21) leading from an air inlet (20a; 20b) to the fuel cell device (11) and the power voltage converter (31) is provided with a cooling body (32) arranged in the air supply duct (21).

3. Fuel cell system according to claim 2, characterized in that the supply air duct (21) is formed in the housing (2) of the fuel cell system (1).

4. Fuel cell system according to one of claims 1 to 3, characterized in that at least one electrical unit compartment (5) is formed in the housing (2) of the fuel cell system (1), in which at least one electrical component of the fuel cell system (1) is arranged, wherein the housing (2) is provided with at least one ventilation opening (35; 36; 37; 40; 41) in the region of the unit compartment (5).

5. Fuel cell system according to claim 4, characterized in that the electrical component is designed as a battery (6), in particular a lithium-ion battery, and / or as an electronic control and / or as a contactor.

6. Fuel cell system according to one of claims 1 to 5, characterized in that the fuel cell device (11) and the fan device (15) are fastened to an aggregate holder (10), wherein the aggregate holder (10) is arranged adjacent to the battery (6).

7. Fuel cell system according to claim 6, characterized in that the unit holder (10) is designed as a cast metal component.

8. Fuel cell system according to one of claims 5 to 7, characterized in that the battery (6) is arranged on a metal casting body (50) which holds a hydrogen tank of the fuel cell system (1).

9. Mobile work machine, in particular industrial truck, with an electric drive system and a fuel cell system (1) according to one of the preceding claims, wherein the fuel cell system (1) is designed to supply the electric drive system of the work machine with electrical energy, and wherein the housing (2) of the fuel cell system (1) is designed to be inserted into a battery receiving space of the work machine.

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