Side channel compressor, method for operating a side channel compressor and fuel cell system

Abstract

Side channel compressor (1) for a fuel cell system (2) for compressing a gaseous medium, comprising a housing with a first housing part (3) and a second housing part (4), wherein the first housing part (3) has a bearing journal (5) extending along an axis of rotation (R) with a journal root section (6) and a journal main section (7), wherein at least one inner bearing ring (8) of a bearing device (9) is arranged on the journal main section (7), wherein a compressor wheel assembly (10) with a compressor wheel (34) is rotatably arranged inside the housing on at least one outer bearing ring (11) of the bearing device (9) about the axis of rotation (R) and can be driven by means of a drive (16), wherein the first housing part (3) is clamped at least indirectly to the bearing device (9) via a fastening element (28) and wherein, in particular in the direction of the axis of rotation (R),A spring element (18) is arranged between the bearing device (9) and the first housing part (3). According to the invention, at least one heating disc (43), which in particular extends circumferentially around the bearing journal (5), is arranged in the region of the journal root section (6). The heating disc (43) is in contact with the spring element (18) in the direction of the axis of rotation (R). The invention further relates to a method for operating the side channel compressor (1) and a fuel cell system (2) with a side channel compressor (1) according to the invention.

Description

[0001] The present invention relates to a side channel compressor for a fuel cell system for compressing a gaseous medium. Furthermore, the invention relates to a method, in particular a cold start procedure, for operating a side channel compressor and to a fuel cell system with a side channel compressor of this type. State of the art

[0002] Rising fuel prices and legal requirements to limit CO2 emissions are prompting automobile manufacturers to increasingly develop drive systems using renewable energy sources. Hydrogen technology offers a promising approach for several reasons, as hydrogen is virtually unlimited as an energy source and its combustion produces no harmful emissions.

[0003] While the direct combustion of hydrogen is a highly complex and currently almost impossible to control process, drive systems are gaining increasing importance in which hydrogen is first used to generate electrical energy, which can then be used to operate an electric motor to power the vehicle. These drive systems incorporate a fuel cell for this purpose.

[0004] By design, fuel cell systems have a hydrogen inlet through which hydrogen can be fed into the fuel cell. On the hydrogen inlet side, fuel cell systems have an anode. For supplying oxygen, fuel cell systems have an oxygen inlet. On the oxygen inlet side, fuel cell systems have a cathode. Finally, fuel cell systems have an exhaust outlet for discharging the fuel cell's exhaust gases. These gases primarily consist of water, a combustion product of the fuel cell, and unused air. Since not all of the hydrogen fed into the fuel cell is combustible during the reaction within the fuel cell, the exhaust gases also include unburned or unused hydrogen.

[0005] To reduce hydrogen consumption in fuel cells, it is now common practice to recirculate unused hydrogen. Recirculation blowers, sometimes featuring so-called "side-channel compressors," are used for this recirculation.

[0006] Side channel compressors come in various designs. Side channel compressors are a type of centrifugal compressor, which can be divided into "star wheel compressors" and "peripheral wheel compressors" based on the impeller used and the fluid flow.

[0007] The fluid to be pumped is fed into the working chamber of the side channel compressor via an inlet connection, which is fluidly coupled to the exhaust outlet of the fuel cell system. A compressor wheel assembly of the side channel compressor, designed as an impeller, is arranged in the working chamber. This impeller assembly is driven by an electric motor and thus rotates. The compressor wheel assembly rotates to axially arranged, one-sided or two-sided lateral flow channels, also referred to as "side channels."

[0008] In this way, the rotating compressor wheel assembly transfers energy to a portion of the flow. The fluid circulates in the blades of the compressor wheel assembly and in the side channels, forming a circulation flow. From this circulation flow, the energy is transferred to the flow in a side channel through momentum exchange. This results in a conversion of velocity energy into pressure energy. The energy transfer occurs multiple times along the entire length of the side channel, allowing for a large energy transfer. This results in a pressure increase at an outlet nozzle of the side channel compressor compared to the inlet nozzle.

[0009] A conventional side channel compressor is known from document DE 10 2018 222 102 A1. The side channel compressor can have the disadvantage that the use of an axial fixation of a rolling bearing to a bearing journal of the housing lower section leads to severe tension and thus to an excessive bearing preload of the bearings. This is particularly due to a preload force of the fixing element, which is designed, for example, as a central screw. This can lead to damage to a bearing device due to a clamping force from the bearing rings, in particular of a respective bearing inner ring and a bearing outer ring, whereby the rolling bearing bodies inside the bearing are damaged. This leads to a reduced bearing service life and thus an increased probability of failure of the side channel compressor. DE 10 2018 207 891 A1 also discloses a side channel compressor in which a spring element is located between a housing part and a bearing.This can lead to the spring element freezing onto the bearing, particularly the inner or outer ring, at low temperatures, particularly below 0°C. If the inner and / or outer rings of the bearings are not rotating, which is not intended, the spring element can be damaged because the spring element also rotates. This can damage the spring element. In particular, if the spring element is designed as a wave spring, this can lead to the wave spring unscrewing, particularly individual windings of the wave spring, which can cause severe damage and / or failure of the wave spring and thus of the side channel blower. Disclosure of the invention

[0010] The present invention relates to a side channel compressor for a fuel cell system for compressing a fluid, having the features of independent claim 1, a method, in particular a cold start procedure, for operating a side channel compressor, having the features of independent claims 8 and 9, and a fuel cell system having a side channel compressor, having the features of independent claim 10. Further features and details of the invention emerge from the subclaims, the description, and the drawings. Features and details described in connection with the side channel compressor according to the invention naturally also apply in connection with the fuel cell system according to the invention, and vice versa, so that reference is always made to the individual aspects of the invention with regard to the disclosure.

[0011] According to a first aspect of the invention, a side channel compressor for a fuel cell system for compressing a gaseous medium is provided. The side channel compressor comprises a housing with a first housing part and a second housing part, wherein the first housing part has a bearing journal extending along a rotational axis R and having a journal root section and a journal main section. A bearing inner ring of a bearing device is arranged on the journal main section, wherein a compressor wheel assembly is arranged within the housing on a bearing outer ring of the bearing device so as to be rotatable about the rotational axis R.The compressor wheel assembly can also be driven by means of a drive, wherein the first housing part is clamped at least indirectly to the bearing device via a fastening element and wherein, in particular in the direction of the rotation axis R, a spring element is arranged between the bearing device and the first housing part.

[0012] The housing is formed by the first housing part and the second housing part. It can be provided according to the invention, but is not absolutely necessary, that the first housing part and / or the second housing part have further housing parts, which can in particular be designed as a housing cover, housing wall or the like. Preferably, the first housing part defines a pre-assembled assembly of the side channel compressor, which has the bearing device and the compressor wheel assembly. A working space for the compressor wheel assembly is formed by the housing, preferably through the interaction of the first housing part with the second housing part.

[0013] The working chamber is preferably fluid-tight, except for a working chamber inlet and a working chamber outlet. Within the scope of the invention, fluid-tight also means that the seal is maintained at a working pressure of the silk-channel compressor that is higher than the ambient pressure. To ensure the seal, sealing devices, such as sealing rings, in particular made of silicone or rubber, or the like, are preferably provided between the first housing part and the second housing part. The first housing part is preferably formed substantially or predominantly from aluminum. The second housing part is preferably formed substantially or predominantly from aluminum.

[0014] The bearing journal is formed as a partial region of the first housing part and extends from an inner wall of the first housing part. According to the invention, the bearing journal is formed monolithically with the first housing part. Alternatively, the bearing journal can also be arranged on the first housing part in a materially bonded manner, for example by welding, or in a force-fitting manner, for example by screwing or pressing. The bearing journal extends from the inner wall of the first housing part, from the journal root section, through the journal main section, to the journal end section.

[0015] The bearing device comprises the bearing inner ring and the bearing outer ring. Preferably, several rolling elements, such as balls, rollers, barrels, or the like, are arranged between the bearing inner ring and the bearing outer ring to support the bearing outer ring on the bearing inner ring with as little play as possible and to ensure relative rotation between the bearing inner ring and the bearing outer ring.

[0016] The bearing inner ring of the bearing device is arranged on the main journal section, preferably with a loose fit. Multiple bearing inner rings can also be arranged on the main journal section, preferably each with a loose fit. The loose fit is preferably designed in such a way that, when the clamping is released, easy movement of the bearing device on the bearing journal, for example, by hand, is ensured, and tilting of the bearing inner ring on the bearing journal is prevented.

[0017] The compressor wheel assembly is arranged on the outer bearing ring of the bearing device, preferably with a press fit. The press fit is preferably designed in such a way that displacement of the compressor wheel assembly on the bearing device is prevented by force-locking. Alternatively, the compressor wheel assembly can be arranged loosely on the outer bearing ring and secured by retaining means against axial slippage from the bearing device.

[0018] With reference to claim 1, the side channel compressor is designed such that at least one heating disc, which in particular runs circumferentially around the bearing journal, is arranged in the region of the journal root section and is in contact with the spring element in the direction of the rotation axis R. In this way, the advantage can be achieved that in the event of a cold start and / or a cold start procedure at temperatures below 0°C, the heating disc can be heated, wherein the heating disc transfers its thermal energy to the spring element and / or other components in contact. In this way, contact points which are connected to one another due to freezing and / or adhesion, for example due to existing ice bridges, are eliminated.These ice bridges can occur when water in the side channel compressor freezes, particularly at temperatures below 0°C, whereby these ice bridges form a positive and / or non-positive connection between components such as the spring element and the bearing inner ring. This in turn leads to the spring element rotating with the bearing inner ring, which damages the bearing inner ring, the spring element or other components. In addition, the spring element can be damaged by what is known as "unwinding", which can lead to total failure of the spring element and also damage surrounding components. The inventive design of the side channel compressor thus has the advantage of preventing the spring element from rotating and / or unscrewing in such a way that the heating disk can be heated by the introduction of external energy.Thus, heating the heating disc enables the rapid removal of ice bridges, particularly through melting, between the spring element and other components. Furthermore, other phenomena that impair frictional and / or positive locking effects due to adhesion, cold welding, or other effects are at least largely eliminated by heating the heating disc. This allows for a reliable and rapid cold start procedure for the side channel compressor and the fuel cell system. This leads to greater reliability of the side channel compressor. This can increase the service life of the spring element and thus of the entire side channel compressor.

[0019] The measures listed in the subclaims enable advantageous developments of the conveying device specified in claim 1. The subclaims relate to preferred developments of the invention.

[0020] According to an advantageous embodiment of the side channel compressor, the heating disk is arranged in the direction of the rotation axis R between the spring element and the bearing inner ring and / or the spring element and the first housing part, in particular in the region of a respective contact point. In this way, the areas in which the spring element is at least indirectly in contact with other components, such as the bearing inner ring or the first housing part, in particular via the respective heating element, can be heated by means of the heating element. This is particularly advantageous during a cold start and / or a cold start procedure of the entire vehicle in which the vehicle is started at temperatures below the freezing point of water, since any ice bridges that may be present between the spring element and other components, such as the bearing inner ring, are thawed.Furthermore, any other frictional and / or positive connections between the spring element and, for example, the bearing inner ring, caused by adhesion, cold welding, or other effects, are eliminated by heating the heating disc. This prevents, for example, the spring element from rotating with the bearing inner ring, thus preventing damage to the spring element due to unscrewing. This has the advantage of reducing the likelihood of damage to the spring element, thus reducing the probability of failure of the entire side channel compressor.

[0021] According to an advantageous development of the side channel compressor, the heating disc is in contact with the spring element and a contact surface of the respective bearing inner ring, in particular such that the spring element is not in direct contact with the contact surface. In this way, the advantage can be achieved that the spring element is not in direct contact and / or contact with the bearing inner ring, since the heating disc is located between the bearing inner ring and the spring element. This prevents the spring element from rotating with the bearing inner ring, which could rotate relative to the bearing journal under certain operating conditions of the side channel compressor, as this rotation is absorbed and thus compensated for by the spring element cap.Furthermore, a spatial separation of the bearing seal from the spring element can be achieved, thus preventing potential damage to the bearing seal, which rotates with the bearing outer ring, caused by a stationary spring element, particularly through frictional contact. This extends the service life of the spring element and / or the bearing seal and / or the bearing device, thereby reducing the probability of failure of the side channel compressor. Furthermore, positioning the heating disc at this location can improve the elimination of ice bridges in the area of ​​the spring element through melting, thereby extending the service life of the spring element and thus of the side channel compressor.

[0022] According to a particularly advantageous embodiment of the side channel compressor, the heating disc is in contact with the spring element and an inner wall of the first housing part, in particular such that the spring element is not in direct contact with the inner wall. In this way, the advantage can be achieved that the spring element is not in direct contact, in particular frictional contact, with the first housing part, in particular the inner wall. The heating disc is located between the spring element and the first housing part. This prevents wear, in particular frictional wear, of the spring element and / or the first housing part at this contact point. In addition, the heating disc can be made of a specially hardened material, so that at least almost no material removal occurs.Without the heating disc, the spring element would remove material, a process known as "digging in," on the first housing section. This would, on the one hand, result in the creation of chips that could damage the bearing assembly and other components of the side channel compressor. On the other hand, the spring element would elongate due to the digging in, so that the preload acting on the bearing assembly would decrease. Since "digging in" of the spring element can be prevented by using the heating disc, the probability of failure of the spring element, the bearing assembly, and the entire side channel compressor can be reduced.In addition, the positioning of the heating disc at this point offers the advantage of preventing the spring element from freezing to the first housing part, particularly due to ice bridges, since the heating disc can be heated during a cold start procedure and can thus achieve an improved elimination of ice bridges in the area of ​​the spring element by melting, which can extend the service life of the spring element and thus of the side channel compressor.

[0023] According to a particularly advantageous embodiment of the side channel compressor, the at least one heating disc comprises a magnetic material, in particular a ferromagnetic material. This provides the advantage that the heating disc can be inductively heated by means of an induction field without the need for electrical contact, for example in the form of a sliding contact in the form of a carbon brush. The sliding contact would be necessary because a relative movement of the heating disc to the housing and / or side channel compressor can occur, but this disadvantageous embodiment can be prevented by the inventive design of the respective heating disc from a ferromagnetic material. In this case, so-called eddy currents arise in the area of ​​the heating disc by means of a generated alternating magnetic field.This alternating field, or the induction field itself, can be generated, for example, by a stator of the drive and a corresponding control of this stator. Alternatively, the induction field that heats the ferromagnetic heating disc can also be generated by another electrical component of the side channel compressor. Furthermore, heat energy can be transferred from the heating disc to other components of the side channel compressor, such as the spring element or the bearing inner ring. This can reduce the risk of spring element failure due to "unwinding" or damage caused by freezing and / or ice bridges, thereby improving the service life of the side channel compressor.

[0024] According to a particularly advantageous development of the side channel compressor, the spring element comprises a magnetic material, in particular a ferromagnetic material or Cr steel. This allows the direct introduction of energy from the generated induction field into the spring element, which leads to heating of the spring element. Thus, existing ice bridges can be removed.

[0025] In a particularly preferred embodiment of the invention, the spring element in the side channel compressor can be designed as a wave spring. A wave spring is inexpensively available and has a characteristic curve that is advantageous for this application. This has the advantage that a reliable and constant provision of the clamping force and / or bearing preload is ensured by the wave spring using simple means and in a cost-effective manner.

[0026] According to an advantageous method for operating the side channel compressor, in particular during a cold start procedure, the stator is energized so that an induction field, in particular an inductive magnetic field, is formed. This results in an inductive transfer of energy to the respective heating disk, whereby the heating disk is thus heated. In an exemplary embodiment of the method, the coils of the stator can be energized for a short time, so that the heating disk heats up due to the resulting power loss. Furthermore, in a further possible embodiment, the stator can be energized using an advantageous method in such a way that an inductive heating of the heating disk occurs, whereby in particular a transfer of heat energy takes place from the heating disk to the spring element.This melts any ice bridges that may be present, and the fluid changes from a solid to a liquid state, allowing it to be drained away, for example, via a purge valve and / or drain valve in the fuel cell system. This can extend the service life of the side channel compressor and / or the fuel cell system.

[0027] According to an advantageous method, the stator is energized without a rotating field building up between the stator and a segment magnet, meaning that there is no or very little rotational movement of the respective segment magnets and thus of a compressor wheel around the axis of rotation. When the stator coils are briefly energized, the stator heats up, particularly due to the resulting power loss, which is released as thermal energy. This thermal energy then spreads from the stator to the other components of the side channel compressor. In addition, in a further possible embodiment, the stator can be energized using an advantageous method in such a way that the segment magnets and the heating disk are inductively heated, with thermal energy being transferred from the heating disk to the spring element.This melts any ice bridges that may be present, and the fluid changes from a solid to a liquid state, allowing it to be drained away, for example, via a purge valve and / or drain valve in the fuel cell system. This prevents the spring element from rotating with the bearing inner ring. This can increase the service life of the side channel compressor and / or the fuel cell system.

[0028] The fuel cell system according to the invention provides all the advantages already described for the side channel compressor according to the first aspect of the invention. Accordingly, the fuel cell system according to the invention has the advantage over conventional fuel cell systems that an improved arrangement of the bearing device on the bearing journal of the side channel compressor is ensured using simple means and in a cost-effective manner.By using the heating element in the area of ​​the journal root section in the immediate vicinity of the spring element, an improved cold-start capability of the side channel compressor and / or the fuel cell system can be achieved by ensuring that, for example, co-rotation of the spring element with the bearing inner ring is prevented by defrosting and eliminating ice bridges using a heatable heating disk. Furthermore, the fuel cell system according to the invention features particularly simple assembly and disassembly of the side channel compressor and is therefore cost-effective to assemble and very easy to maintain. Furthermore, the fuel cell system according to the invention features particularly low operating noise.

[0029] The invention is not limited to the embodiments described here and the aspects highlighted therein. Rather, numerous modifications are possible within the scope of the claims, which are within the scope of one skilled in the art. Short description of the drawing

[0030] The invention is described in more detail below with reference to the drawing.

[0031] It shows: Fig. 1 shows a sectional view of a side channel compressor according to the prior art, Fig. 2 in a sectional view a Fig. 1 section of the side channel compressor marked II with at least one bearing and one spring element according to the state of the art, Fig. 3 in a sectional view a section of the side channel compressor according to the invention with two bearings, the spring element and two heating discs, Fig. 4 shows a plan view of a fuel cell system according to a preferred embodiment of the invention.

[0032] Elements with the same function and mode of action are listed in the Fig. 1 to 4 are each provided with the same reference numerals.

[0033] In Fig. 1 shows a schematic sectional view of a side channel compressor 1 according to the prior art. The side channel compressor 1 has a housing with a first housing part 3 and a second housing part 4. The first housing part 3 has a bearing journal 5 extending in the direction of the second housing part 4 and a bearing device 9 with two rolling bearings 19, 20 arranged on the bearing journal 5. The first bearing 19 and the second bearing 20b of the bearing device 9 are arranged next to one another in the direction of a rotation axis R. In addition, a spacer disk 15 is located between the rolling bearings 20a, b, with the bearing outer rings 11a, b in particular being in contact with the spacer disk 15 axially to the rotation axis R. Bearing inner rings 8 of the bearing device 9 are arranged on the bearing journal 5. A compressor wheel assembly 10 with a compressor wheel 34 is arranged on bearing outer rings 11 of the bearing device 9.In addition, the side channel compressor 1 has a compressor chamber 36 which runs circumferentially around the rotation axis R and which has at least one circumferential side channel 35.

[0034] As in Fig. 1, the bearing journal 5 has a blind hole in which a fastening element 28, in particular a clamping bolt 28, is arranged. The bearings 20 are clamped at least indirectly to the first housing part 3 via the clamping bolt 28 and a spring element 18, wherein the first housing part 3 is clamped at least indirectly to the bearing device 9 via the fastening element 28. In this case, a bearing stop disk 12 can be arranged in the direction of the rotation axis R between the fastening element 28, in particular an enlarged screw head, and the bearing journal 5 and / or the respective bearing inner ring 8. Furthermore, the bearing stop disk 12 can be at least indirectly connected via a spacer sleeve 14 (shown in Fig. 3) with an end face of the bearing journal 5 in the direction of the rotation axis 46. By machining the spacer sleeve 14 prior to assembly, a bearing preload of the respective bearing 19, 20 can now be achieved, in particular by means of a bearing preload force 39.

[0035] By screwing in the clamping bolt 28, a preload force 39 acting parallel to the rotation axis R is applied to the bearing device 9. Furthermore, it is shown that in the direction of the rotation axis R, four axial gaps 33a, b, c, d are located in the area between the compressor wheel assembly 10 and a respective housing part 3, 4, wherein the axial gaps 33a, b, c, d encapsulate the compressor chamber 30. The bearing journal 5 has an inner wall 17 (shown in Fig. 2) of the first housing part 3, and a journal main section 7 directly adjacent to the journal root section 6. Two bearing inner rings 8 of two rolling bearings 20 are arranged on the journal main section 7.

[0036] In addition, Fig. 1 shows that a drive 16 is designed as an axial-field electric motor 16 having a stator 13. By energizing the stator 13, a magnetic field is generated which acts on a segment magnet 44 of the compressor wheel assembly 10 such that the compressor wheel assembly 10 is set in rotation. In one exemplary embodiment, a hub 37 can have a recess 45 extending annularly around the rotation axis R, wherein the components return ring 46 and at least two segment magnets 44, ideally four segment magnets 44, are located at least almost entirely in the recess 45.

[0037] Fig. 2 shows a sectional view of a Fig. 1 shows a section of the side channel compressor 1, designated II, with at least one bearing 19, 20 and a spring element 18 according to the prior art. It is shown that the second bearing 20 has the bearing outer ring 11b and the bearing inner ring 8b. The bearing outer ring 11b is in contact with the spacer disk 15 in the direction of the rotation axis R. At least one bearing seal 42 is located between the bearing inner ring 8b and the bearing outer ring 11b in order to encapsulate the interior of the bearing, thereby preventing in particular the escape of a lubricant from the interior of the bearing, but also preventing contamination of the interior of the bearing by particles from outside the respective bearing. The bearing inner ring 8b is in contact at least indirectly with the spring element 18 in the direction of the rotation axis R.The spring element 18 is supported on one side on a contact surface 40 of the bearing inner ring 8b and on the other side on the inner wall 17 of the first housing part 3. The spring element 18 acts with a spring force acting at least almost in the direction of the rotation axis R in the area of ​​the contact points of the spring element 18 with the contact surface 40 and / or the inner wall 17.

[0038] As in Fig. 2, a respective wear area 41 can form in which the spring element 18, which is made of a harder material than the friction partners, damages the friction partners 8b, 3 and can lead to material removal, particularly in the respective wear area 41. Increased wear can occur if the bearing inner ring 8b, which should not rotate on the bearing journal 5 during normal operation, does rotate at certain operating points of the side channel compressor 1. In certain operating situations of the entire vehicle at low temperatures, particularly below 0°C, for example during a long shutdown period of the entire vehicle and a subsequent cold start procedure, the spring element 18 can freeze to the respective bearing 19, 20, particularly to the bearing inner ring 8.Freezing can occur due to ice bridges, particularly at temperatures below 0°C, where the ice bridges can create a positive and / or non-positive connection between the bearing inner ring 8 and the spring element 18. If the bearing inner ring 8 rotates, which is not intended, this can lead to damage to the spring element 18, as the spring element 18 also rotates. This can damage the spring element 18. In particular, if the spring element 18 is designed as a wave spring 18, the wave spring 18 can unscrew, in particular individual windings of the wave spring 18, which leads to severe damage and / or failure of the wave spring 18 and thus of the side channel blower 1. Furthermore, this rotation can lead to considerable wear on the bearing inner ring 8b and / or the spring element 18. In addition, an unscrewed winding can damage the bearing seal 42.

[0039] Fig. 3 shows a sectional view of a section of the side channel compressor 1 according to the invention with two bearings 19, 20, the spring element 18 and two heating disks 43a, b. This shows a first heating disk 43a and a second heating disk 43b, which each run in particular circumferentially around the bearing journal 5. The respective heating disk 43 is arranged in the region of the journal root section 6 and is in contact with the spring element 18 in the direction of the rotation axis R. The heating disk 43 can be arranged in the direction of the rotation axis R between the spring element 18 and the bearing inner ring 8 and / or the spring element 18 and the first housing part 3, in particular in the region of a respective contact point 41a, b. In this case, the first heating disc 43a can be in contact with the spring element 18 and the contact surface 40 of the respective bearing inner ring 8, in particular so that the spring element 18 is not in direct contact with the contact surface 40.In addition, the second heating disk 43b can be in contact with the spring element 18 and the inner wall 17 of the first housing part 3, in particular so that the spring element 18 is not in direct contact with the inner wall 17. Furthermore, it is shown that the spacer disk 15 is located axially to the rotation axis R between the bearing outer ring 11a of the first bearing 19 and the bearing outer ring 11b of the second bearing 20.

[0040] As in Fig. 3, the at least one heating disk 43 comprises a magnetic material, in particular a ferromagnetic material. Furthermore, the spring element 18 can comprise a magnetic material, in particular a ferromagnetic material. The spring element 18 can also be designed as a corrugated spring 18. According to the invention, a method for operating the side channel compressor 1, in particular during a cold start procedure, is claimed. Within the scope of this method, an induction field, in particular an inductive magnetic field, is formed by energizing the stator 13, thus resulting in an inductive energy transfer to the respective heating disk 43.In addition, by means of the method according to the invention, the stator 13 can be energized without a rotating field building up between the stator 13 and at least one segment magnet 44, and thus no or very little rotational movement of the respective segment magnets 44 and thus of the compressor wheel 34 about the axis of rotation 4 occurs. By means of the respective method according to the invention, thawing of the contact points 41 between the spring element 18 and the respective bearing inner ring 8 and / or the spring element 18 and the first housing part 3 can be ensured, wherein an acceleration of the cold start procedure of the side channel compressor 1 and / or a fuel cell system 2 can be ensured by heating the respective heating disk 43.

[0041] In Fig.4, the fuel cell system 2 according to a preferred embodiment of the invention is shown schematically in a plan view. The fuel cell system 2 has a fuel cell 21 with an anode 25 and a cathode 26, which are surrounded by an electrolyte 27. A membrane 29 is arranged between the anode 25 and the cathode 26. Adjacent to the anode 25, the fuel cell 21 has a hydrogen inlet 23 for supplying hydrogen. Adjacent to the cathode 26, the fuel cell 21 has an oxygen inlet 22 for supplying oxygen or an oxygen-containing gas mixture, such as filtered air, and an exhaust gas outlet 24 for discharging exhaust gases from the fuel cell 21. A water separator 30 for separating water from the exhaust gas and the side channel compressor 1 according to the invention are arranged at the exhaust gas outlet 24.

[0042] Furthermore, a working chamber inlet 31 of the side channel compressor 1 is fluidly coupled to the exhaust gas outlet 24, so that exhaust gas from the exhaust gas outlet 24 can be fed to a working chamber of the side channel compressor 1 for compression via the working chamber inlet 31. A working chamber outlet 32 ​​of the side channel compressor 1 is fluidly coupled to the hydrogen inlet 23, so that hydrogen from the working chamber can be fed back to the fuel cell 21 via the working chamber outlet 32 ​​and the hydrogen inlet 23. QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] DE 10 2018 222 102 A1

[0009] DE 10 2018 207 891 A1

[0009]

Claims

[1] Side channel compressor (1) for a fuel cell system (2) for compressing a gaseous medium, comprising a housing with a first housing part (3) and a second housing part (4), wherein the first housing part (3) has a bearing journal (5) extending along a rotational axis R with a journal root section (6) and a journal main section (7), wherein at least one bearing inner ring (8) of a bearing device (9) is arranged on the journal main section (7), wherein a compressor wheel assembly (10) with a compressor wheel (34) is arranged within the housing on at least one bearing outer ring (11) of the bearing device (9) so as to be rotatable about the rotational axis R and is drivable by means of a drive (16), wherein the first housing part (3) is clamped at least indirectly to the bearing device (9) via a fastening element (28) and wherein, in particular in the direction of the rotational axis R,a spring element (18) is arranged between the bearing device (9) and the first housing part (3), characterized by that at least one heating disc (43), which in particular runs circumferentially around the bearing journal (5), is arranged in the region of the journal root section (6) and is in contact with the spring element (18) in the direction of the rotation axis R. [2] Side channel compressor (1) according to claim 1, characterized by that the heating disc (43) is arranged in the direction of the rotation axis R between the spring element (18) and the bearing inner ring (8) and / or the spring element (18) and the first housing part (3), in particular in the region of a respective contact point (41a, b). [3] Side channel compressor (1) according to claim 1 or 2, characterized bythat the heating disc (43) is in contact with the spring element (18) and a contact surface (40) of the respective bearing inner ring (8), in particular so that the spring element (18) is not in direct contact with the contact surface (40). [4] Side channel compressor (1) according to claim 1 or 2, characterized by that the heating disc (43) is in contact with the spring element (18) and an inner wall (17) of the first housing part (3), in particular so that the spring element (18) is not in direct contact with the inner wall (17). [5] Side channel compressor (1) according to one of the preceding claims, characterized by that the at least one heating disc (43) comprises a magnetic material, in particular a ferromagnetic material. [6] Side channel compressor (1) according to one of the preceding claims, characterized by that the spring element (18) comprises a magnetic material, in particular a ferromagnetic material. [7] Side channel compressor (1) according to one of the preceding claims, characterized by that the spring element (18) is designed as a corrugated spring (18). [8] Method for operating the side channel compressor (1), in particular within the framework of a cold start procedure, according to one of the preceding claims, characterized by that by means of the current supply to a stator (13) an induction field, in particular an inductive magnetic field, is formed, whereby an inductive energy transfer to the respective heating disc (43) is thus established. [9] Method according to claim 8, characterized by that the stator (13) is energized without a rotating field being built up between the stator (13) and at least one segment magnet (44), and thus no or very little rotational movement of the respective segment magnets (44) and thus of the compressor wheel (34) about the axis of rotation (4) occurs. [10] Fuel cell system (2), comprising a fuel cell (21) with an oxygen inlet (22), a hydrogen inlet (23), an exhaust gas outlet (24), an anode (25), a cathode (26) and an electrolyte (27), characterized by that the fuel cell system (2) has a side channel compressor (1) according to one of the preceding claims, which is fluidly coupled to the exhaust gas outlet (24).

Images