The invention relates to a coolant circuit for a fuel cell system, which comprises at least one coolant line, through which coolant is able to flow in the cooling operation. An ion exchanger module can be fluidically coupled with the at least one coolant line. Furthermore, the coolant circuit comprises at least one closing element, formed to close the at least one coolant line. The coolant circuit is, in particular, provided for a fuel cell system of a vehicle. Furthermore, the invention relates to a method to operate a coolant circuit for a fuel cell system.
The coolant used in the coolant circuit of a fuel cell system must be highly purified, in particular with regard to metal ions. Metal ions in particular can contaminate the polymer electrolyte membrane (PEM) or the catalyst layers of fuel cells. In order to ensure the purity of the coolant, an ion exchanger module, for example in the form of an ion exchanger cartridge, is integrated into the coolant circuit of the fuel cell system. The ion exchange capacity of the ion exchanger material present in the cartridge diminishes over time, such that the cartridge must be exchanged regularly. During the exchange of the ion exchanger module, the risk exists, however, that impurities reach the coolant.
DE 11 2007 001 478 T5 describes an ion exchanger for a fuel cell vehicle. The ion exchanger is arranged in a chamber surrounded by a shock absorber and a mud guard of the vehicle. If an ion exchanger application of the ion exchanger is removed and replaced, then the coolant lines fixed in the vehicle are closed with sealing plugs. Thus the coolant is prevented from leaking or foreign bodies are prevented from reaching the coolant.
Furthermore, it is known from prior art to introduce ion exchanger material into the coolant circuit in loose form or in a small bag or pouch in place of an ion exchanger cartridge. If a pouch with ion exchanger resin is introduced, for example, into a coolant expansion tank, then, as a rule, this does not lead to the desired ion exchanger effect, as the coolant preferably flows around the pouch and does not flow through the pouch. In the case of ion exchanger material poured into the coolant circuit in loose form, this material can be uncontrollably displaced in the coolant circuit and can lead to blockages, sedimentation or mechanical damage. In this way a coolant pump can be damaged or coolant channels inside the fuel cells can be blocked. This can lead to disturbances in the function of the fuel cell system and entail costly repairs or maintenance. Thus, an ion exchanger module, which can be fluidically coupled with the coolant lines of the coolant circuit, is useful with regard to the functionability of the fuel cell system.
The object of the present invention is to create a coolant circuit of the type named at the beginning, as well as a method to operate such a coolant circuit, one or both of which reduces the risk of contamination of the coolant in a particularly simple way.
This object is solved by a coolant circuit with the features of claim 1 as well as by a method with the features of claim 10. Advantageous embodiments with expedient developments of the invention are specified in the dependant claims.
The coolant circuit according to the invention for a fuel cell system, in particular of a vehicle, comprises at least one coolant line, through which coolant is able to flow in the cooling operation. An ion exchanger module can be—at least indirectly—fluidically coupled with the at least one coolant line. Furthermore, the coolant circuit comprises at least one closing element, by means of which the at least one coolant line is able to be closed. Here, it is effected that the at least one coolant line is closed by means of the at least one closing element through an uncoupling of the ion exchanger module from the at least one coolant line. In other words, the closing of the at least one coolant line occurs automatically, in that the ion exchanger module is fluidically uncoupled from the at least one coolant line.
Through such an automatic closing mechanism, it is ensured that the closing element closes the allocated coolant line in the case of a replacement of the ion exchanger module, already indirectly after the removal thereof by a component of the coolant circuit—so with the interruption of the fluidic coupling. Then no impurities can enter the coolant line. The risk of contamination is herein reduced in a particularly simple way, as sealing plugs do not need to be laboriously inserted into the cooling lines, but rather the closing is effected simply by the removal of the ion exchanger modules.
The closing of the coolant line is also not able to be forgotten, as is possible in the case of the provision of separate sealing plugs as closing elements. Forgetting a sealing plug can lead to a leakage of the coolant and consequently to an overheating of the fuel cells or to an emergency shut down during of the operation of the fuel cell system. In the case of a fuel cell system provided to drive a vehicle, the vehicle can then not longer move along. This can be prevented presently by the closing element that automatically closes the cooling line.
In the case of an ion exchanger module, which is not properly installed in the coolant circuit, the coolant lines are thus presently closed, and it is no longer damaging if a new, unused ion exchanger module is not installed directly after the removal of the exhausted ion exchanger module in the coolant circuit.
The coolant line, which can be closed by means of the closing element, can in particular be a coolant flow line and/or a coolant return line.
In an advantageous embodiment of the invention, the at least one closing element is also formed to uncover the at least one coolant line, wherein the uncovering or opening of the coolant line can be effected by the—at least indirect—fluidic coupling of the ion exchanger module with the same. Thus, an automatic opening mechanism is also provided, such that not only the closing but also the opening of the coolant line is particularly effortless. To uncover the coolant line, the ion exchanger module simply needs to be installed. Furthermore, in the case of the dismantled ion exchanger module, damage to the fuel cells by the impurities, which have entered the coolant, is avoidable.
It is particularly simple if the at least one closing element is formed as a non-return valve. Such a valve can easily be pushed open by the ion exchanger module during installation of the same, and thus opened. The pushing open of the non-return valve can in particular be effected by the corresponding formation of an inlet opening and/or of an outlet opening of the ion exchanger module, so, for example, by a protruding inlet nozzle or outlet nozzle. The non-return valve closes automatically if the ion exchanger module is removed from the coolant circuit.
Additionally or alternatively, a closing flap can be provided to close the at least one coolant line, which can be pushed downwards, upwards or away by the ion exchanger module during installation and can thus be opened. Such a closing flap can—for example with regard to the coolant level in a coolant expansion tank—be arranged horizontally or vertically. Here, an inlet opening and/or an outlet opening of the ion exchanger module can effect the opening of the closing flap during the fluidic coupling of the ion exchanger module with the at least one coolant line. The reliable and cost-effective closing flap closes automatically if the ion exchanger module is dismantled. An axis of rotation of the closing flap can, in particular—for example as in the case of a sealing butterfly valve—be arranged in the centre, wherein the closing and/or uncovering of the coolant line can be effected by rotating an axle arranged in the central axis.
Additionally or alternatively, at least one turntable can be provided as a closing element, said turntable having at least one opening. By rotating the turntable, the opening, for example in the form of a continuous bore hole, of a channel, of a plurality of holes, of openings arranged in a fan shape or similar, can be overlapped with the cross section of the coolant line, which is able to be flowed through, in order to uncover the coolant line. If the turntable is rotated further, then this effects a closing of the coolant line. Also, the turntable is formed in such a way that it is rotated into an initial closing position during dismantling of the ion exchanger module. The turntable can be arranged horizontally or vertically with respect to an axial direction of the coolant line or to the coolant level, in the same way as the closing flap.
Preferably, the turntable is already rotated by the installation of the ion exchanger module, such that coolant leaving or entering the coolant line is able to flow through its at least one opening. Here, an inlet opening and/or an outlet opening of the ion exchanger module can also effect the rotating of the turntable. Additionally or alternatively, carrier elements can be provided on the ion exchanger module, and the turntable can be rotated by means of the ion exchanger module.
If a narrow side of the turntable is arranged perpendicularly to the axial direction of the coolant line, the turntable can, in particular, be rotatable around its central point or eccentrically in order to effect the closing or uncovering of the coolant line. The turntable can also be formed in the manner of a serrated increment circle, which is then rotatable by means of a serrated actuating element. The turntable can also comprise a basic body and a cloak-like covering element, which is rotatable relative to this basic body, or a sleeve or similar parts that are firmly connected to one another, wherein the closing or uncovering of the coolant line is effected by rotating the covering element. The covering element can also be formed immovably and the basic body enclosed by the covering element can be formed rotatably.
A further possibility consists in providing a circle segment as a closing element, which is rotated in order to close or uncover the coolant line. Similarly, this can be effected by rotating a hollow body, which in particular can be formed cylindrically. If an opening, provided in such a cylindrical or tubular hollow body, is overlapped by the cross section of the coolant line, which is able to be flowed through, then the coolant line is uncovered.
The at least one closing element can also be formed as a bolt and/or a slider, which can effect the closing and/or uncovering of the coolant line. The bolt or slider can itself have at least one opening, for example a bore hole, a channel, a plurality of holes, openings arranged in a fan shape or similar, or it can be pushed away from the coolant line to be closed, in order to uncover this. The slider or bolt can also be arranged horizontally or vertically in the coolant circuit. The installation of the ion exchanger module in the coolant circuit preferably effects a rotation or shifting of the bolt or slider, in order to ensure that coolant line can be flowed through. During the removal of the ion exchanger module, the bolt or slider move back into an initial closing position. During the installation of the ion exchanger module, the inlet opening and/or outlet opening thereof can effect the movement of the bolt or slider. The slider can, in particular, be formed in the manner of a mechanical shutter, for example in the manner of an iris shutter for a camera, or in the manner of a fan, which in particular has blades, or a telescope mechanism can be provided.
For a particularly secure closing of the coolant line, each coolant line can also be provided with a plurality of the named closing elements. The different, presently described closing elements can also be used in combination.
It has been shown to be further advantageous if at least one actuating element to actuate the at least one closing element is arranged on the ion exchanger module. Then the closing element does not need to be actuated by means of the inlet opening or the outlet opening of the ion exchanger module, but rather the actuating element, which is particularly suited for this purpose, can be used. The actuating element can thus be designed particularly robustly with regard to operational safety and susceptibility to closing. Such an actuating element can in particular be formed as a mandrel or a cone or a cam or a wedge or as a sphere or as a tappet or a gear rack. Actuating elements of this sort in combination with one another can also effect the actuation of the at least one closing element or several closing elements.
The closing element can be arranged partially outside components of the coolant circuit and the actuating element can be arranged completely outside components of the coolant circuit, through which coolant flows in the cooling operation. For example, the actuating element can be fixed on a fixing flange of the ion exchanger module, said actuating element then actuating the closing element during installation of the ion exchanger module in the coolant circuit. Then the actuating element does not come into contact with the coolant.
It is preferable, however, that at least one closing element is arranged completely in a position, which is wettable by the coolant in the cooling operation and that at least one actuating element is arranged at least partially in a position, which is wettable by the coolant in the cooling operation. Then the closing element and the actuating element are particularly well protected.
According to a further advantageous embodiment of the invention, the at least one closing element can comprise an electrical and/or electromechanical actuator, which is able to be actuated by closing an electrical contact. Here, the closing of the electrical contract by the uncoupling of the ion exchanger module from the at least one coolant line is able to be actuated. Additionally or alternatively to a mechanical opening or closing mechanism, an electrical or electromechanical closing mechanism or opening mechanism can be used.
The closing of the electrical contact can additionally or alternatively be effected by the fluidic coupling of the ion exchanger module with the at least one coolant line. Then the installation of the ion exchanger module in the coolant circuit leads to the electrical contact being closed and thus the actuator being actuated, wherein the actuator then effects an uncovering of the coolant line. Simple and functionally reliable electrical shut-off valves, throttle valves or similar can be used as electrical or electromechanical actuators. The electrical contact can, in particular, be formed as a finger contact.
Additionally or alternatively to the electrical contact, a contactless, controllable switch can be provided, the closing of which is actuated by the actuator. Such a contactless switch can, for example, be formed as a magnetic switch, in particular as a magnetic passive switch and/or it can comprise a chip, as is used in an RFID system (Radio Frequency Identification).
In particular, when providing a RFID system, which comprises a transponder and a reader, not only the actuation of the actuator can be effected by the control of the contactless switch, but also it can be additionally ensured that only the provided ion exchanger module can be installed in the coolant circuit, in order to avoid problems and risks through the installation of unsuitable ion exchanger modules. By providing actuators, which are able to be actuated by the closing of the electrical contact or of the switch that is able to be controlled contactlessly, wearing can be kept particularly low in comparison to mechanical opening or closing mechanisms.
It has been shown to be further advantageous if a switch is able to be actuated by the uncoupling of the ion exchanger module from the coolant line and/or by the fluidic coupling of these components, by means of which at least one functional unit of the coolant circuit is controllable. Such a switch can be formed as an electromechanical switch, for example as a micro-contact switch or as a magnetic switch, or can comprise an electrical contact, in particular a finger contact. Thus, the electrical energy flow to the functional units can be influenced—directly or via a control device—by the deinstallation or installation of the ion exchanger module.
The functional unit can comprise an electrical coolant pump or an electrical thermostat, such that the coolant flow can be decreased or interrupted during the uncoupling of the ion exchanger module from the coolant line. In this way, the coupling or uncoupling of the ion exchanger module simultaneously effects an activation or deactivation of at least one functional unit of the coolant circuit. If the actuation of the switch by the uncoupling of the ion exchanger module from the coolant line is triggered, the deinstallation of the ion exchanger module can ensure an interruption of the coolant flow, without a further operational step needing to be carried out for this.
The actuation of the switch by the installation or deinstallation of the ion exchanger module can additionally or alternatively produce a signal. If the signal is transmitted to a control device of the fuel cell system, then this can ensure that a starting up of the fuel cell stack is prevented if the ion exchanger module is removed, in order to, for example, prevent any damage to the fuel cell stack.
Additionally or alternatively the signal can be able to be communicated to an operator, for example in that an optical and/or audible warning message is emitted in the arrangement of the fuel cell system in the vehicle, for example via an instrument panel. Then the operator is informed that a start-up of the fuel cell system should be stopped due to the present lack of ion exchanger module. The signal can also generate error codes, for example for diagnostic purposes. Such error codes can be found during troubleshooting or a test or by carrying out a test, in particular a short test.
In a further advantageous embodiment of the invention, a mechanical and/or electronic coding is provided, by means of which the fluidic coupling of an ion exchanger module that is not suited to the coolant circuit with the at least one coolant line is able to be interrupted. It is thus ensured that only a suitable ion exchanger module can be installed in the coolant circuit, as the installation of an unsuitable ion exchanger module could possibly cause damage to the fuel cell stack. A pairing of a key bit and a key opening or keyhole can be provided as a mechanical coding, or fixing or carrier elements or similar can be arranged in such a way that only the installation of the suitable ion exchanger module in the coolant circuit is possible. The electronic coding can occur in particular via an RFID system.
The ion exchanger module can be able to be introduced into the coolant circuit by plugging in and/or screwing in and/or locking into place and/or rotating the same. Here, it is particularly advantageous if reaching an installation position is accompanied by an optical and/or audible and/or perceptible response. Thus, for example, a defined end stop can be provided, which specifies when the provided installation position is reached. Also, the weight of the ion exchanger cartridge can ensure that this has reached the desired installation position during installation. If the ion exchanger module is rotated, in order to bring it into the installation position, then a defined rotation, for example of a quarter or a half of a complete rotation, can be provided.
In the method according to the invention to operate a coolant circuit for a fuel cell system, at least one coolant line, which coolant is able to flow through in the cooling operation, is closed by means of at least one closing element. Here, the closing of the at least one coolant line is effected by the ion exchanger module being uncoupled from the at least one coolant line. In other words, the—at least indirect—fluidic coupling of the ion exchanger module with the coolant line is removed. Due to the automatic closing of the coolant line effected in this way, the risk of contamination of the coolant during the exchange of the ion exchanger module is decreased.
The advantages described for the coolant circuit according to the invention and preferred embodiments are also valid for the method according to the invention.
The features and combinations of features named above in the description, as well as the features and combinations of features named below in the description of the figures and/or shown below in the figures alone are not only able to be used in the respective specified combination, but also in other combinations or on their own, without exceeding the scope of the invention.
Further advantages, features and details of the invention arise from the claims, the description below of preferred embodiments, as well as by means of the drawings, in which identical or functionally identical elements are provided with identical reference numerals. Herein are shown:
In
In the depicted example, the valve plate 7 of the non-return valve 8 is under the initial tension of a spring 11, which ensures that the non-return valve 8 automatically closes the coolant line 3 as soon as the ion exchanger cartridge 4 is removed from the coolant container 2. The direction of insertion of the ion exchanger cartridge 4 into the coolant container 2 is illustrated in
The actuating element formed in
For example, in the embodiment of the coolant circuit 1 shown in
In the embodiment of the coolant circuit 1 shown in
In the case of the coolant circuit 1 according to
The channel 29 can be overlapped by the coolant line 3 by rotating the turntable 24 in a rotation direction specified in
Ion exchanger cartridge 4 and turntable 24 can thus be formed such that they form the complementary parts of a joint, such that they can be joined or assembled together in a detachable way. It is particularly advantageous if both joining parts, i.e. ion exchanger cartridge 4 and turntable 24, are formed such that they result in a bayonet joint. Both joining parts can then be coupled by setting, i.e. by an insertion and rotating movement. Ion exchanger cartridge 4 and turntable 24 can thus be fluidically coupled in a particularly quick and secure manner, and also later uncoupled.
In the embodiment of the coolant circuit 1 shown in
In the embodiment of the coolant circuit 1 shown in
In the embodiment of the coolant circuit 1 shown in
In the embodiment of the coolant circuit 1 shown in
The actuating element 36 has a recess 39, which uncovers the inlet opening of the coolant line 3 into the coolant container 2 in the case of an ion exchanger cartridge 4 being inserted into the coolant container 2.
An installation direction is also specified in
The coding ensures that only an ion exchanger cartridge 4 can be installed and used in the coolant circuit 1. Additionally, it is thus ensured that only the ion exchanger cartridge 4 that is provided for and therefore corresponds to the coolant circuit 1 can be properly inserted.
In place of the mechanical opening and closing mechanisms described presently by means of the figures, a closing or uncovering of the coolant line 3, effected by closing an electrical contact, can also be provided. Here, an electrical or electromechanical actuator, for example an electrical throttle valve or an electrical shut-off valve, can be used.
Additionally or alternatively to the mechanical coding, an electronic coding can also be provided, for example in the form of an RFID system, which ensures that only the suitable ion exchanger cartridge 4 can be installed in the coolant circuit 1.
The closing elements, shown presently as an example, to close and uncover the coolant line 3, can have a plurality of geometric shapes and can be formed, for example as a sphere, cone, cylinder, plate or similar. The surfaces of these closing elements, which effect the closing, can have different shapes such as that of a rectangle, a square, a circle or similar. The same applies for sealing elements, which can be provided on the closing elements.
In terms of materials for the closing elements, preferred are those which are compatible with the deionised coolants of the coolant circuit 1, in particular comprising distilled water. Thus, plastic, rubber, stainless steel, fibre reinforced plastic, in particular glass fibre reinforced plastic or similar can be used as a material. The presently named shapes and materials can also be provided for the actuating elements.
Whilst, in the figures, the closing elements are presently shown to be arranged in immovable components of the coolant circuit 1, for example in the coolant container 2, in alternative embodiments closing elements of this kind can additionally be provided on the ion exchanger cartridge 4. A respective actuating element can then be provided on sides of the components of the coolant circuit 1 which are immovable during the exchange of the ion exchanger cartridge 4. Then such a closing element in the removed ion exchanger cartridge 4 prevents an undesired leakage of the ion exchanger material 5 from the same.
Number | Date | Country | Kind |
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10 2011 100 711.7 | May 2011 | DE | national |
Filing Document | Filing Date | Country | Kind | 371c Date |
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PCT/EP2012/001572 | 4/11/2012 | WO | 00 | 10/31/2013 |