Method and device for cooling at least one electrical or electronic component enclosed in a housing, and fuel cell system with a cooling device

Abstract

The invention relates to a method for cooling at least one electrical or electronic component (2) contained in a housing (1), in which a dielectric fluid (3) is passed through the housing (1) so that the at least one electrical or electronic component (2) is directly surrounded by the fluid (3). The invention further relates to a device (10) for carrying out the method and to a fuel cell system with a device (10) according to the invention.

Description

[0001] The invention relates to a method for cooling at least one electrical or electronic component housed in a housing. The at least one electrical or electronic component to be cooled can, in particular, be a component of power electronics for a fuel cell system. Furthermore, the invention relates to a device for cooling at least one electrical or electronic component housed in a housing. The device is particularly suitable for carrying out the method according to the invention.

[0002] The preferred field of application of the invention is fuel cell systems, in particular mobile fuel cell systems or fuel cell vehicles. State of the art

[0003] Electrical or electronic components generate heat or waste heat during operation. This heat must be dissipated to prevent the component from overheating. This is especially true if the component is enclosed. Otherwise, there is a risk that the component's function will be impaired.

[0004] Often, the housing itself is used for cooling. Cooling then occurs passively, as the housing absorbs heat from the inside and dissipates it to the outside. To increase the heat-transfer surface area, the housing can incorporate cooling fins or similar components. The disadvantage of this approach is the multiple heat transfers, as each heat transfer point limits the heat flow, thus reducing the cooling effectiveness.

[0005] For active cooling, the housing can be designed with a double wall, creating a hollow space that can be filled with a cooling medium. For this purpose, the housing must be connected to a cooling circuit with a circulating coolant. However, this does not reduce the number of heat transfers.

[0006] The present invention is concerned with the task of optimizing the cooling of an electrical or electronic component accommodated in a housing.

[0007] To achieve this objective, the method having the features of claim 1 and the device having the features of claim 9 are proposed. Advantageous developments of the invention can be found in the respective subclaims. Furthermore, a fuel cell system with a device according to the invention is specified. Disclosure of the invention

[0008] A method is proposed for cooling at least one electrical or electronic component housed in a housing. In the method, a dielectric fluid is passed through the housing so that the fluid flows directly around the at least one electrical or electronic component.

[0009] The advantage of the proposed method is that the heat or waste heat generated by the electrical or electronic component during operation can be directly absorbed and dissipated by the fluid. Thus, only one heat transfer occurs from the component to be cooled to the fluid. Because the fluid flows around the component, a large surface area is available for heat transfer. Cooling is therefore particularly effective.

[0010] Since a dielectric fluid is used in the method, improved electrical insulation of the at least one electrical or electronic component from its environment can be achieved at the same time, in particular with regard to the clearance and creepage distance properties.

[0011] According to a preferred embodiment of the invention, the dielectric fluid is passed through a fluid-tight, closed volume within the housing, in which the at least one electrical or electronic component is accommodated. The fluid-tight, closed volume can be formed by the housing itself, so that the entire free volume of the housing is exposed to the dielectric fluid. However, the volume can also be a separate area within the housing, so that the dielectric fluid is passed through only a portion of the housing.

[0012] In a further development of the invention, it is proposed that the dielectric fluid be specifically directed by at least one flow-directing structure as it passes through the housing. The fluid can then be specifically directed or directed into areas that are particularly thermally critical and / or in which particularly high waste heat is generated by the at least one electrical or electronic component. The fluid then absorbs the waste heat and dissipates it.

[0013] Preferably, a dielectric cooling medium of a cooling circuit is used as the dielectric fluid. This approach is particularly suitable when a cooling circuit with a dielectric cooling medium is already present, so that no separate cooling circuit needs to be constructed. If the invention is used in a fuel cell system, the cooling circuit used to cool a fuel cell stack of the fuel cell system can be used.

[0014] Furthermore, polyalphaolefin or deionized water can preferably be used as the dielectric fluid. If no cooling circuit with a suitable cooling medium is available, such a cooling circuit must be provided separately.

[0015] Furthermore, it is proposed that a fuel gas, preferably hydrogen, be used as the dielectric fluid. This is particularly advantageous when the invention is applied in a fuel cell system, since fuel gas is already present in a fuel cell system. This means that an existing fluid can be used as the dielectric fluid, and no separate dielectric fluid needs to be maintained. An additional reservoir for the dielectric fluid can thus be omitted, which helps save space and costs.

[0016] The fuel gas in a fuel cell system is typically stored in a compressed gas container. The fuel gas extracted from the compressed gas container is therefore under pressure. In a further development of the invention, it is therefore proposed that the fuel gas be extracted from a compressed gas container and depressurized before being introduced into the housing or within the housing.

[0017] During operation of a fuel cell system, the fuel gas pressure is also adjusted to the pressure required for injection. Since heat is extracted from the environment when adjusting the fuel gas pressure, the fuel gas must be heated before use to prevent excessive cooling and the associated condensate formation in the fuel cell system's anode system. A heat exchanger is typically used to heat the fuel gas.

[0018] The use of a heat exchanger for heating the fuel gas in a fuel cell system may be dispensed with if—according to a preferred embodiment of the invention—the fuel gas is tempered using the waste heat from the at least one electrical or electronic component and then made available to the fuel cell system as anode gas. In this way, the waste heat from the at least one electrical or electronic component can not only be safely dissipated but also put to use.

[0019] Furthermore, a device for cooling at least one electrical or electronic component accommodated in a housing is proposed. The device comprises a fluid-tight, closed volume formed within the housing, in which the at least one electrical or electronic component is accommodated, as well as a fluid inlet communicating with the volume and a fluid outlet for a dielectric fluid.

[0020] The proposed device is particularly suitable for implementing the previously described method according to the invention, so that the same advantages can be achieved. In particular, the waste heat of the at least one electrical or electronic component can be dissipated particularly effectively, since the component is directly surrounded by the dielectric fluid. The waste heat is then dissipated from the housing via the fluid. If an already existing fluid is used, the cooling efficiency can be increased at the same time, since no additional fluid needs to be stored.

[0021] If the device is used in a fuel cell system, fuel gas, particularly hydrogen, can be used as the dielectric fluid. Since the fluid is heated by the waste heat of the at least one electrical or electronic component, it can subsequently be made available to the fuel cell system as anode gas. The anode gas is then already tempered, potentially eliminating the need for a heat exchanger to heat the fuel gas.

[0022] Preferably, the fluid-tight, closed volume is defined by at least one housing wall and / or by at least one partition wall incorporated within the housing. Certain areas that are not to be exposed to the dielectric fluid can be separated by the at least one partition wall. In this case, the fluid is only directed through a portion of the housing.

[0023] Furthermore, at least one flow-directing structure is preferably arranged in the fluid-tight, closed volume. The flow-directing structure can be used to direct the fluid in a targeted manner, for example, into an area that is particularly thermally critical and / or where the waste heat is particularly high.

[0024] Furthermore, a device for depressurizing the dielectric fluid is preferably integrated into the fluid inlet or into the housing. This is particularly advantageous when using a fluid stored in a compressed gas container, as is the case, for example, with fuel gas in a fuel cell system. The depressurizing device can then be used to adjust the pressure level of the fluid.

[0025] Since the proposed device is preferably used in a fuel cell system, a fuel cell system with a device according to the invention for cooling at least one electrical or electronic component of a power electronics system of the fuel cell system is also proposed. Furthermore, the device can be used to control the temperature of fuel gas, which can then be used as anode gas.

[0026] A preferred embodiment of the invention is explained in more detail below with reference to the accompanying drawings. These show: Fig. 1 a schematic plan view of a device according to the invention, comprising a housing in which at least one electrical or electronic component is accommodated, and Fig. 2 a schematic longitudinal section through the housing of the device of Fig. 1 along line AA. Detailed description of the drawings

[0027] The Fig. 1 is a simplified representation of a device 10 according to the invention for cooling an electrical or electronic component 2 accommodated in a housing 1. The housing 1 is a component of the device 10. The at least one component 2 accommodated in the housing 1 can be, for example, power electronics for a fuel cell system.

[0028] The housing 1 of the illustrated device 10 has a fluid inlet 5 and a fluid outlet 6 for a dielectric fluid 3, for example fuel gas.

[0029] As in particular the Fig. As can be seen from Figure 2, the housing 1 has four housing walls 7, a base 8, and a cover 9, which fluid-tightly define a volume 4 communicating with the fluid inlet 5 and the fluid outlet 6. The at least one electrical or electronic component 2 is accommodated in the volume 4.

[0030] Since the at least one electrical or electronic component 2 generates waste heat during operation, it must be cooled. For this purpose, the volume 4 is supplied with the dielectric fluid 3, or the dielectric fluid 3 is introduced into the volume 4 via the fluid inlet 5 and discharged again via the fluid outlet 6. The dielectric fluid 3 flows around the at least one electrical or electronic component 2, so that the dielectric fluid 3 absorbs the waste heat generated by the component 2 and dissipates it from the housing 1.

Claims

[1] Method for cooling at least one electrical or electronic component (2) accommodated in a housing (1), in which a dielectric fluid (3) is passed through the housing (1) so that the at least one electrical or electronic component (2) is directly surrounded by the fluid (3). [2] Method according to claim 1, characterized by that the dielectric fluid is passed within the housing (1) through a fluid-tight closed volume (4) in which the at least one electrical or electronic component is accommodated. [3] Method according to claim 1 or 2, characterized by that the dielectric fluid (3) is specifically guided by at least one flow-directing structure as it passes through the housing (1). [4] Method according to one of the preceding claims, characterized by that a dielectric cooling medium of a cooling circuit is used as the dielectric fluid (3). [5] Method according to one of claims 1 to 3, characterized by that polyalphaolefin or deionized water is used as dielectric fluid (3). [6] Method according to one of claims 1 to 3, characterized by that a fuel gas, preferably hydrogen, is used as the dielectric fluid (3). [7] Method according to claim 6, characterized by that the fuel gas is taken from a pressurised gas container and is expanded before being introduced into the housing (1) or in the housing (1). [8] Method according to claim 6 or 7, characterized by that the fuel gas is tempered with the aid of the waste heat of the at least one electrical or electronic component (2) and is then made available to a fuel cell system as anode gas. [9] Device (10) for cooling at least one electrical or electronic component (2) accommodated in a housing (1), comprising a fluid-tight closed volume (4) formed within the housing (1), in which the at least one electrical or electronic component (2) is accommodated, and a fluid inlet (5) communicating with the volume (4) and a fluid outlet (6) for a dielectric fluid (3). [10] Device (10) according to claim 9, characterized by that the fluid-tight closed volume (4) is delimited by at least one housing wall (7) and / or by at least one partition wall accommodated in the housing (1). [11] Device (10) according to claim 9 or 10, characterized by that at least one flow-directing structure is arranged in the fluid-tight closed volume (4). [12] Device (10) according to one of claims 9 to 11, characterized bythat a device for relaxing the dielectric fluid (3) is integrated into the fluid inlet (5) or into the housing (1). [13] Fuel cell system with a device (10) according to one of claims 9 to 12 for cooling at least one electrical or electronic component of a power electronics unit of the fuel cell system.

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