AT526079A4 - Water separator for a fuel cell system, fuel cell system, ultrasonic measuring system and measuring method - Google Patents

Abstract

The present invention relates to a water separator (10) for a fuel cell system (100), wherein the water separator (10) has an inlet opening (16) for an anode discharge section (122) of the fuel cell system (100) for admitting anode exhaust gas (3) from the fuel cell system (100 ), a storage volume (4) for storing water (1) separated from the anode exhaust gas (3) and an outlet opening (14) for discharging the water (1) stored in the storage volume (4), the water separator (10). Ultrasonic measuring system (20) with at least one ultrasonic sensor (22, 24) for measuring a water level (2) of the water (1) and for measuring a hydrogen concentration of the anode exhaust gas (3).

Description

Ultrasonic measuring system and measuring method

The present invention relates to a water separator for a fuel cell system, wherein the water separator has an inlet opening for an anode discharge section of the fuel cell system for admitting anode exhaust gas from the fuel cell system, a storage volume for storing water separated from the anode exhaust gas and an outlet opening for discharging the water stored in the storage volume . The invention also relates to a fuel cell system with such a water separator, an ultrasonic measuring system for a water separator and a measuring method for the water separator.

the, the fuel cell system or the ultrasonic measuring system.

Particularly in PEM fuel cell systems, it is very important to supply the anode with sufficient hydrogen. An undersupply of hydrogen can lead to very strong degradation effects and significantly shorten the service life of the fuel cell stack or fuel cell system. On the other hand, hydrogen waste must be avoided. Therefore, measuring the hydrogen concentration can enable optimization in terms of efficiency and performance.

allow usage time.

Measuring the hydrogen concentration in fuel cell systems, especially those for motor vehicles, can be a major challenge because there is very little space for integrating additional sensors. Existing solutions require a lot of installation space for the integration of corresponding sensors. However, smaller (automotive) sensors on the market are not very useful due to the humid and acidic environment in the anode of the fuel cell system

robust.

Cost-intensive mass spectrometers are currently used to measure the concentration of hydrogen, which usually constantly extract gas from the anode volume.

men in the fuel cell stack, which should be avoided.

It is the object of the present invention to at least partially eliminate the disadvantages described above. In particular, it is the task of the present invention

dung, in a cost-effective and simple way, a space-optimized and

to provide.

The above object is achieved by a water separator with the features of claim 1, a fuel cell system with the features of claim 11, an ultrasonic measuring system according to claim 12 and a measuring method with the features of claim 13. Further features and details of the invention emerge from the subclaims, the description and the drawings. Features and details that are described in connection with the water separator according to the invention naturally also apply in connection with the fuel cell system according to the invention, the ultrasonic measuring system according to the invention, the measuring method according to the invention and vice versa, so that the disclosure of the individual aspects of the invention is always mutual.

is or can be properly referred to.

According to the invention, a water separator for a fuel cell system is provided, wherein the water separator has an inlet opening for an anode discharge section of the fuel cell system for admitting anode exhaust gas from the fuel cell system, a storage volume for storing water separated from the anode exhaust gas, and an outlet opening for discharging the water stored in the storage volume. The water separator further has an ultrasonic measuring system with at least one ultrasonic sensor for measuring a water level of the water, in particular in the storage volume, and for measuring a hydrogen concentration of the anode exhaust gas, in particular in the storage

cher volume, on.

According to the invention, an ultrasonic measuring system is used which can measure both the water level of the water separator and the hydrogen concentration in the water separator with one or more sensors in a water separator. In contrast to the prior art, no different measuring systems and sensors are necessary. The provision according to the invention of the single measuring system for both measurements therefore not only allows a compact use of installation space within and/or on the water separator and thus in the fuel cell system, but is also cost-effective and allows particularly precise

Measurement using the same ultrasonic measuring principle. This measuring principle is included

robust to the operating conditions in the anode loop with the liquid

Water droplets. It can also be built very compactly to meet the space requirements

to further minimize. Providing two measurement options also improves this

Calibration and thus optimization of the fuel cell system.

It can be advantageous if a first ultrasonic sensor is set up to measure the water level of the water and a second ultrasonic sensor is set up to measure the hydrogen concentration of the anode exhaust gas. This means that the ultrasonic measuring system has at least two ultrasonic sensors, each of which can carry out different types of measurements, which are later also referred to as level measurements and concentration measurements. The devices of the sensors for these different measuring tasks can be implemented, for example, through their structure, their relative positioning or the positioning of their measuring direction and/or additional possible elements, such as measuring element surfaces. This advantageously allows both the water level and the hydrogen concentration to be measured at the same time, so that these are permanently monitored.

can be awakened.

It can also be advantageous if the two ultrasonic sensors are arranged on the same wall section of the water separator. The wall section can be, for example, a side wall, in particular an inner side wall, of the water separator. This enables a comparatively particularly compact design because the ultrasonic sensors do not have to be far from each other and therefore from other measuring system components, which in turn requires additional installation space, for example due to appropriate cabling

would cause costs.

It can also be advantageous if the two ultrasonic sensors are arranged next to each other. This means that the two ultrasonic sensors are in close proximity to each other. This also allows the previously mentioned compact setup

building.

Furthermore, it can be advantageous if the ultrasonic measuring system has at least one measuring system component, which the two ultrasonic sensors at least partially share. Such at least one measuring system component can be

for example, a measurement control device, cabling, a power supply, etc.

The fact that the two ultrasonic sensors are at least one or more

or share all measurement system components required for the measurements,

can provide redundancy in the components that could prevent possible failure

Measuring system components for a compact and cost-effective design

of the ultrasonic measuring system and thus the fuel cell system in which it is incorporated

is set, should be avoided.

It can also be advantageous if the at least one ultrasonic sensor and/or one measuring element surface of the ultrasonic measuring system is mounted movably between two measuring positions in order to measure the water level of the water in a level measuring position of the two measuring positions and in a concentration measuring position to measure the hydrogen concentration of the anode exhaust gas in both measuring positions. The movable bearing can be provided, for example, by a rotary bearing and/or translational bearing, which enables rotation or translational movement of the at least one ultrasonic sensor and/or the measuring element surface. For the movement, a drive can be provided on the measuring element surface and/or the at least one ultrasonic sensor, which is correspondingly controlled by the ultrasonic measuring system in order to provide one of the two measuring positions. This makes it possible for a single ultrasonic sensor to take on both types of measurements, i.e. concentration measurements and level measurements. This can be helpful if one of two possible ultrasonic sensors fails. The ultrasonic measuring system can also be equipped with just one ultrasonic sensor, which can carry out both types of measurements depending on the selected measuring position. At least for a precise measurement, typically only one time-separated measurement of water is required.

level and concentration measurement may be possible.

It can be advantageous if the at least one ultrasonic sensor has a measuring direction aligned with a water surface of the water stored in the storage volume for measuring the hydrogen concentration of the anode exhaust gas. Equipped with this measuring direction, the ultrasonic sensor can determine the distance between the at least one ultrasonic sensor and the water surface as the level of the storage volume. This distance can be assigned to a water level if the dimensions of the water separator are known. example-

For example, a formula, a mapping table or the like can be used by the ultrasound

Assign a water level to the distance measured by the sensor

Ultrasonic measuring system can be determined. The level measuring position can then

in particular be a measuring position in which the measuring direction of the ultrasonic transmitter

sors is aligned with the water surface.

It can also be advantageous if the at least one ultrasonic sensor has a measuring direction for measuring the hydrogen concentration that is aligned with a measuring element surface of the ultrasonic measuring system in the water separator. This means that the hydrogen concentration can be measured, particularly in a different measuring direction.

than that for measuring the water level.

In principle, it can also be advantageous if the measurement of the hydrogen concentration is carried out in the same measuring direction as the measurement of the water level. For this purpose, a fixed geometry (in addition to the water surface, i.e. the “measuring element surface”) can advantageously be present in the “viewing direction” of the sound source and the two different ones through appropriate signal analysis and/or processing

Signals (level and concentration) can be separated.

The measuring element surface can preferably be arranged on a measuring element within the water separator, in particular within the storage volume. Such a measuring element can, for example, protrude from an inner wall of the water separator towards the inside of the water separator, in particular into the storage volume, or can be designed as an inner wall of the water separator. The measuring element can be made of a solid material, for example plastic, metal or the like, which preferably has sufficient resistive properties for use in the water separator, that is, for example, can have a specific coating. The measuring element can also be made of the same material as the wall of the water separator,

in particular be designed in one piece with this.

The measuring element surface can advantageously have a predetermined distance from the at least one ultrasonic sensor. Because the distance is predetermined, it is always known and so the ultrasound, once emitted by the ultrasonic sensor, requires a different amount of time for different hydrogen concentrations until it is released from the measuring element surface

is reflected and registered again on the ultrasonic sensor. Here too you can

for example a formula, an assignment table or the like for the respective one

Duration from emission to reception of the ultrasound for each hydrogen

concentration, which are determined by the ultrasonic measuring system.

that can. With a movably mounted measuring element surface, the distance can be

optionally also be adjustable, although the distance can be determined by a measurement or

predetermined storage positions of the measuring element surface are known.

The present invention also relates to a fuel cell system, comprising at least one fuel cell stack with an anode section and a cathode section, an anode supply section for supplying anode supply gas to the anode section, a cathode supply section for supplying cathode supply gas to the cathode section, an anode discharge section for discharging anode exhaust gas, and a cathode discharge section for Removal of cathode exhaust gas, with a water removal according to the invention in the anode removal section

separator is arranged.

A fuel cell system according to the invention thus brings with it the same advantages as have been explained in detail with reference to the water separator according to the invention. The fuel cell system can be of any type, including:

For example, it can be of the polymer electrolyte membrane (PEM for short) type.

The present invention also relates to an ultrasonic measuring system for a water separator, in particular the water separator according to the invention, for a fuel cell system, in particular the fuel cell system according to the invention, wherein the ultrasonic measuring system has at least one ultrasonic sensor for measuring a water level of water in the water separator and for measuring a hydrogen concentration of an anode exhaust gas in the water waste

has a separator.

An ultrasonic measuring system according to the invention thus brings with it the same advantages as described in detail with reference to the water separator according to the invention

have been explained.

Furthermore, the subject of the present invention is also a measuring method for the water separator according to the invention, for the fuel cell according to the invention

system or for the ultrasonic measuring system according to the invention, whereby the

measuring system:

— level measurement of the water level of the water and — concentration measurement of the hydrogen concentration of the anode exhaust gas.

A measuring method according to the invention therefore also brings with it the same advantages as those described in detail with reference to the water separator according to the invention

have been explained.

It can be advantageous here if the level measurement and the concentration measurement are carried out at the same time, at least temporarily. This has the advantage that the water level and the hydrogen concentration can be monitored at least temporarily in parallel, in particular continuously, in particular by means of two

Ultrasonic sensors of the ultrasonic measuring system.

However, it can also be advantageous if the level measurement and the concentration measurement are carried out at separate times. This has the advantage that this process requires a single ultrasonic sensor for both the fill level

measurement as well as concentration measurement can be used.

Further advantages, features and details of the invention emerge from the following description, in which reference is made to the drawings.

Examples of leadership are described in detail. It shows schematically:

Fig. 1 is a schematic view of an exemplary embodiment of a

fuel cell system according to the invention,

Fig. 2 is a schematic detailed view of a water separator according to the invention according to an exemplary embodiment of the invention

from the fuel cell system of Fig. 1,

Fig. 3 is a schematic view of a movably mounted ultrasonic sensor of an ultrasonic measuring system in the water separator of Fig. 2

7

5 is a schematic view of a second exemplary embodiment of a measuring method according to the invention for the ultrasonic measuring system.

tem of the water separator of Fig. 2.

Identical or functionally identical elements are shown in Figures 1 to 5 with the

referred to by the same reference numerals.

1 shows schematically an exemplary embodiment of a fuel cell system 100 according to the invention. The fuel cell system 100 is shown here purely as an example with a single fuel cell stack 110 with an anode section 112 and a cathode section 114, although of course several fuel cell stacks 110 can also be provided. An anode supply section 120 serves to supply anode supply gas to the anode section 112 and a cathode supply section 140 serves to supply cathode supply gas to the cathode section 114. Again, an anode discharge section 122 serves to discharge anode exhaust gas, and a cathode discharge section 142 serves to discharge cathode gas.

the exhaust.

As part of this anode discharge section 122, a water separator 10 is integrated into it, which allows water 1 (see FIG. 2) or, to be more precise, product water from the anode exhaust gas 3 (see FIG. 2) to be separated in the anode discharge section 122. This separated water 1 can be discharged via a water outlet 12 of the valve device 30, either out of the fuel cell system 100 or within the fuel cell system 100 for further use.

be circulated.

During operation, anode supply gas is now introduced into the anode section 112 of the fuel cell stack 110 through the anode supply section 120. Spent anode exhaust gas 3 is removed via the anode discharge section 122 and, as explained, runs through the water separator 10. In addition to being discharged via a so-called purge valve to the environment and/or into the cathode discharge section, it can, as before

mentioned, also a recirculation of the anode exhaust gas 3 via the passive one shown

Recirculation device, for example in the form of an ejector device 150, takes place

gen. The water separator 10 can of course also be used in the recirculation system.

section 130 or even in the anode supply section 120 downstream of the passive

The recirculation device can be arranged here in the form of the ejector device 150.

the.

Figure 2 shows the water separator 10 from Figure 1 in more detail. The water separator 10 is shown in a purely schematic manner as a simple container, which is typically not the case because it is usually constructed in a much more complex manner in order to effectively separate the water 1 therein. The illustration serves this purpose

merely for a better understanding of the invention.

The water separator 10 comprises a storage volume 4, illustrated here as an example, for storing the water 1 separated from the anode exhaust gas 3. Furthermore, the water separator 10 comprises an inlet opening 16, which is fluidly connected to the anode discharge section 122. In fact, the anode discharge section 122 is also fluidly connected to the water separator 10 elsewhere. The water separator 10 also includes an outlet opening 14, which is fluidly connected to the water outlet 12 of the valve device 30 in order to be from

Anode exhaust gas 3 to be able to release separated and stored water 1.

Finally, the water separator 10 also includes an ultrasonic measuring system 20, which is arranged here, for example, on an upper wall section of the water separator 10 in FIG. 2. The ultrasonic measuring system 20 includes here both

for example two ultrasonic sensors 22, 24.

A first ultrasonic sensor 22 is set up to measure the water level of the water 1. For this purpose, it is aligned in its measuring direction 5 shown with the water surface of the stored water 1 in the storage volume 4. The water surface has a certain water level 2 that needs to be determined. For this purpose, the first ultrasonic sensor 22 sends out ultrasound towards the water surface and receives it after a time that depends on the distance between the first ultrasonic sensor 22 and the water surface. By measuring this time between sending and receiving the ultrasound, the ultrasound measuring system can

20 calculate the water level 2 back.

sound sensor 24 calculates the hydrogen concentration in the anode exhaust gas 3.

Advantageously for the installation space and costs of the water separator 10, the two ultrasonic sensors 22, 24 here use a common measuring system component 26, which is shown here as an example outside the water separator 10. The measuring system component 26 can, for example, be a measuring control device including a power supply

be.

As an alternative to using two ultrasonic sensors 22, 24 in the ultrasonic measuring system 20, FIG. 3 shows an exemplary embodiment in which a single ultrasonic sensor 22 is used to measure both the water level 2 and the hydrogen concentration. In order to change the respective measuring direction 5 of the ultrasonic sensor 22, the ultrasonic sensor 22 is movably mounted, in particular rotatably mounted, so that it can carry out a rotation R, as shown in FIG Ultrasonic sensor 22 can be conveyed. In position P1 of the ultrasonic sensor 22 shown on the left, which is a fill level position P1, the measuring direction 5 is aligned with the water surface. This makes it possible to measure the water level 2 using ultrasound. If the rotation R is now carried out in the direction shown in FIG. 3, the position P2 indicated on the right in FIG. 3 is assumed, which is a concentration measuring position P2. In the concentration measuring position P2, the ultrasonic sensor 22 is aligned with its measuring direction 5 towards the particularly fixed measuring element surface 18, as shown in FIG. 2. This makes it possible to measure the hydrogen concentration in the concentration measuring position P2. Changing the measuring direction 5 of the ultrasonic sensor 22 allows concentration measurement

as well as level measurement.

Alternatively or in addition to the movable mounting and moving the ultrasonic sensor 22, it is also possible to design the measuring element surface 18 to be movable. For example, it is conceivable to move the measuring element surface 18 in front of the ultrasonic sensor 22 to assume the concentration measuring positions P2, so that its measuring direction 5 is aligned with it. On the other hand, the measuring element surface 18 can then be moved away from in front of the ultrasonic sensor 22 in order to align its measuring direction 5 again with the water surface. It is therefore also possible not to change the measuring direction 5 itself in order to enable the concentration measurement and the level measurement using only one ultrasonic sensor 22, but rather the surface to be measured in front of the ultrasonic sensor 22 is changed, i.e. the water surface on the one hand and on the other the measuring element surface.

Figures 4 and 5 show exemplary embodiments of measuring methods 200, which are used by the

Ultrasonic measuring systems 20 described here can be carried out.

In the measuring method 200 of FIG. 4, the level measurement 202 of the water level 2 of the water 1 and the concentration measurement 204 of the hydrogen concentration of the anode exhaust gas 3 take place one after the other in time. This measuring method 200 can relate in particular to the design of the ultrasonic measuring system 20 of FIG. 3. In this respect, the level measurement 202 and the concentration measurement 204 can be used by one and the same ultrasonic sensor 22. As an optional intermediate step, a movement step 206 can take place between the level measurement 202 and the concentration measurement 204, as shown in FIG. 4. In this optional movement step 206, the previously explained movement of the ultrasonic sensor 22 and/or the measuring element surface 18 can take place in order to switch between the two measuring positions P1, P2. Of course, in the measuring method 200 of FIG. 4, the concentration measurement 204 and then the level measurement 202 can also be carried out the other way around. The measuring method 200 shown can also be repeated, for which purpose a movement step 206 can take place between one of the two measuring steps 202, 204 in order to achieve the required

appropriate measuring position P1, P2 for the following measuring step 202, 204.

In contrast, in the measuring method 200 of FIG. 5, the level measurement takes place

202 of the water level 2 of the water 1 through the first ultrasonic sensor 22

2 and the concentration measurement 204 of the hydrogen concentration of the ano-

the exhaust gas 3 through the second ultrasonic sensor 24 in parallel in time. In this respect

This measuring method 200 applies in particular to the exemplary embodiment of

Ultrasonic measuring system 20 of the water separator 10 of FIG. 2.

The above explanation of the embodiments describes the present invention exclusively in the context of examples; of course, individual features of the embodiments can be freely combined with each other if technically sensible.

be ned without departing from the scope of the present invention.

The above explanations of the embodiments describe the present

present invention exclusively within the scope of examples.

Reference symbol list

1 water

2 water level

3 anode exhaust

4 storage volumes

5 measuring direction

10 water separators

12 water outlet

14 outlet opening

16 inlet opening

18 measuring element surface 20 ultrasonic measuring system 22 first ultrasonic sensor 24 second ultrasonic sensor 26 measuring system component 30 valve device

100 fuel cell system 110 fuel cell stack 112 anode section

114 cathode section

120 anode feed section 122 anode discharge section 130 recirculation section 140 cathode feed section 142 cathode discharge section 150 ejector device

200 measuring methods

202 level measurements

204 Concentration measurement 206 Movement step

P1 level measuring position P2 concentration measuring position R rotation

Claims (15)

Patent claims 1. Water separator (10) for a fuel cell system (100), wherein the water separator (10) has an inlet opening (16) for an anode discharge section (122) of the fuel cell system (100) for admitting anode exhaust gas (3) from the fuel cell system (100). Storage volume (4) for storing water (1) separated from the anode exhaust gas (3) and an outlet opening (14) for discharging the water (1) stored in the storage volume (4), characterized in that the water separator (10). Ultrasonic measuring system (20) with at least one ultrasonic sensor (22, 24) for measuring a water level (2) of the water (1) and for measuring a water serstoff concentration of the anode exhaust gas (3). 2. Water separator (10) according to claim 1, characterized in that a first ultrasonic sensor (22) for measuring the water level (2) of the water (1) and a second ultrasonic sensor (24) for measuring the hydrogen concentration centering of the anode exhaust gas (3) is set up. 3. Water separator (10) according to claim 2, characterized in that the two ultrasonic sensors (22, 24) on the same wall section of the Water separator (10) are arranged. 4. Water separator (10) according to claim 2 or 3, characterized in that the two ultrasonic sensors (22, 24) are arranged next to each other. 5. Water separator (10) according to one of claims 2 to 4, characterized in that the ultrasonic measuring system (20) has at least one measuring system component (26) which is the two ultrasonic sensors (22, 24). at least partially share. 6. Water separator (10) according to one of the preceding claims, characterized in that the at least one ultrasonic sensor (22, 24) and / or a measuring element surface (18) of the ultrasonic measuring system (20) between two measuring positions (P1, P2) is movably mounted in order to measure the water level (2) of the two measuring positions (P1, P2) in a level measuring position (P1). Water (1) to be measured and in a concentration measuring position (P2). ses (3) to measure. 7. Water separator (10) according to one of the preceding claims, characterized in that the at least one ultrasonic sensor (22, 24) has a measuring direction (5) aligned with a water surface of the water (1) stored in the storage volume (4) for measuring the Hydrogen concentration of the Anode exhaust gas (3). 8. Water separator (10) according to one of the preceding claims, characterized in that the at least one ultrasonic sensor (22, 24) has a measuring direction (5) aligned with a measuring element surface (18) of the ultrasonic measuring system (20) in the water separator (10). ) for measuring the hydrogen concentration has centering. 9. Water separator (10) according to claim 8, characterized in that the measuring element surface (18) on an element within the storage volume (4) is arranged. 10. Water separator (10) according to claim 8 or 9, characterized in that the measuring element surface (18) is a predetermined distance from the to- has at least one ultrasonic sensor (22, 24). 11. Fuel cell system (100), comprising - at least one fuel cell stack (110) with an anode section (112) and a cathode section (114), - an anode supply section (120) for supplying anode supply gas to the anode section (112), - a cathode feed section (140) for feeding cathode feed gas to the cathode section (114), - an anode discharge section (122) for discharging anode exhaust gas, and - a cathode discharge section (142) for discharging cathode exhaust gas, Features of one of the preceding claims is arranged. 12. Ultrasonic measuring system (20) for a water separator (10) for a fuel cell system (100), characterized in that the ultrasonic measuring system (20) has at least one ultrasonic sensor (22, 24) for measuring a water level (2). Water (1) in the water separator (10) and for measuring a hydrogen concentration of an anode exhaust gas (3) in the water separator (10). 13. Measuring method (200) for a water separator (10) according to one of claims 1 to 10, for a fuel cell system (100) according to claim 11 or for an ultrasonic measuring system (20) according to claim 12, characterized in that the measuring method (200 ) includes the following steps, each using of the ultrasonic measuring system (20): — level measurement (202) of the water level (2) of the water (1) and — Concentration measurement (204) of the hydrogen concentration of the anode exhaust gas (3). 14. Measuring method (200) according to claim 13, characterized in that the level measurement (202) and the concentration measurement (204) at least in time carried out at the same time. 15. Measuring method (200) according to claim 13, characterized in that the level measurement (202) and the concentration measurement (204) are separated in time be carried out by each other.