Filter device for filtering and drying a liquid, use of such a filter device, and immersion cooling system for a vehicle with such a filter device

Abstract

The present invention relates to a filter device (1) comprising a housing (2) through which a flow path (12) for liquid extends, a filter element (15) for filtering the liquid arranged in the housing (2), and a drying device (16) arranged in the housing (2) with a desiccant (17) for drying the liquid. A key feature of the invention is that the drying device (16) radially surrounds the filter element (15) so that the outer surface (18) of the filter element (15) has a first surface section (19) covered by the drying device (16) and a second surface section (20), and that the flow path (12) in the housing (2) is divided into two partial paths (21, 22). The invention relates in particular to an immersion cooling system for a vehicle with such a filter device (1) and, furthermore, in particular, to the use of such a filter device (1).

Description

[0001] The invention relates to a filter device for filtering and drying a liquid, which, according to the preamble of claim 1, comprises a hollow cylindrical housing extending along a central axis and enclosing a volume through which the liquid flows along a flow path from an inlet of the housing to an outlet of the housing. The filter device further comprises a filter element for filtering the liquid, which is arranged within the volume of the housing. The invention relates in particular to a novel use of such a filter device and, more specifically, to an immersion cooling system for a vehicle with such a filter device.

[0002] A filter device for filtering and drying a liquid of the type mentioned above is known from publication DE 10 2019 122 034 A1.

[0003] The known filter device is designed to remove foreign particles and dissolved or free water from a fluid circulating in a closed loop. This water can damage fluid components integrated into the loop, for example through corrosion, or cause electrical short circuits. For this purpose, the known filter device is equipped with a flow-through filter element for separating foreign particles and a flow-through drying unit. This drying unit binds water entrained in the fluid using a desiccant stored within the unit. The latter process is also referred to as "drying" the fluid.A disadvantage is that the known filter device has a relatively high overall pressure drop, since the pressure drop component resulting from the drying device and the pressure drop component generated by the filter element add up. From a fluid mechanics perspective, the known filter device is therefore unfavorable for flow through.

[0004] The object of the invention is therefore to provide an improved or at least a different embodiment of a filter device for filtering and drying a liquid. In particular, a filter device with improved fluid-mechanical properties is to be specified. Furthermore, an application of such a filter device is to be specified. In particular, an attempt is made to specify an advantageous immersion cooling system for a vehicle.

[0005] In the present invention, this problem is solved by the subject matter of the independent claims. Advantageous embodiments are the subject matter of the dependent claims, the description, and the drawings.

[0006] To solve this problem, the invention proposes that a filter device for filtering and drying a liquid, in particular an oil filter, in combination with the features mentioned above, includes a drying device arranged within the volume of the housing and shaped like a hollow cylinder, with a drying agent for drying the liquid. A fluid-mechanical improvement can be achieved by having the drying device radially enclose an outer surface of the filter element such that the outer surface of the filter element is divided into a first circumferential section covered by the drying device and a second circumferential section, which is not covered by the drying device and projects beyond it in the direction of the central axis.In the filter device according to the invention, the flow path within the volume of the housing is thus divided into two partial paths. The first partial path of these two partial paths leads through the drying device via an outer surface of the drying device and through the first section of the outer surface of the filter element, so that during operation of the filter device, liquid flows sequentially along the first partial path through the drying device and then through the filter element. Furthermore, the second partial path of these two partial paths leads through the filter element via the second section of the outer surface of the filter element, so that during operation of the filter device, liquid flows exclusively through the filter element along the second partial path.

[0007] The total achievable pressure drop of the proposed filter system is relatively low compared to that of the known filter system. This is because, unlike the known filter system, the liquid in the proposed system is divided into two flows, which flow through the filter system along the two aforementioned partial paths. The first pressure drop component, occurring along the second partial path (where only the filter element is flowed through), is significantly lower than the second pressure drop component, occurring along the first partial path (where both the drying unit and the filter element are flowed through). The total pressure drop resulting from the sum of the first and second pressure drop components is therefore comparatively low, making the proposed filter system fluid-efficient.The proposed design of the filter device according to the invention is based in particular on the inventors' realization that the liquid flowing into the proposed filter device can be dried sufficiently, i.e., adequately with regard to the requirements of a circuit in which the filter device is to be used, if not the entire liquid flow, but only a predetermined portion of the liquid flow, is dried by means of the filter device. This has the advantage that the liquid flowing through the filter device during operation is completely filtered with a comparatively small pressure drop, and a sufficient portion of the liquid flow is dried.

[0008] The liquid in question can be a cooling liquid, preferably a dielectric cooling liquid, in particular a dielectric liquid mixture.

[0009] The drying agent used to dry the liquid may preferably comprise zeolites and / or silica gel or be formed from zeolites and / or silica gel.

[0010] The filter element can be a ring filter element. Furthermore, the drying device can be axially fitted over the ring filter element, such that the ring filter element projects axially beyond the drying device in the direction of the central axis. Additionally, the housing and / or the drying device can be aligned coaxially with respect to the central axis within the volume of the housing.

[0011] Furthermore, it should be noted that the terms "axial" and "radial" used herein conveniently refer to the central axis of the hollow cylindrical housing of the filter device. The term "axial" is conveniently understood as a direction parallel or coaxial to the central axis. Furthermore, the term "radial" is conveniently understood as a direction perpendicular, and in particular perpendicular, to the central axis.

[0012] It is also possible to adjust or optimize the achievable total pressure drop of the proposed filter device and / or the degree of liquid drying achievable with the proposed filter device, such that sufficient liquid drying is achieved at an acceptable total pressure drop. This is possible by providing a predetermined area ratio between the first and second sections of the outer surface of the filter element. The preferred area ratio of the first to the second section is in the range of 10:1 to 1:1, and particularly 6:1.As a result, the first lateral surface section of the outer surface of the filter element, through which the first partial path passes, tends to be larger in area than the second lateral surface section of the outer surface of the filter element.

[0013] Furthermore, the filter element can be designed with an axial height extending along the central axis, and the drying unit can also have an axial height extending along the central axis. To achieve a favorable overall pressure drop with the proposed filter unit, it is advantageous for the axial filter element height to be greater than or equal to the axial drying unit height. Moreover, the aforementioned area ratio between the first segment of the outer surface of the filter element and the second segment of the outer surface of the filter element can be easily adjusted by modifying the axial filter element height or the axial drying unit height. A preferred height ratio of the axial filter element height to the axial drying unit height can be in the range of 10:1 to 1:1, particularly 6:1.

[0014] Advantageously, the first segment of the outer surface of the filter element is arranged closer to the outlet of the housing than to the inlet along the flow path. Furthermore, the second segment of the outer surface of the filter element can be arranged closer to the inlet of the housing than to the outlet. This places the second segment of the flow path upstream of the first, so that the second segment, which causes a lower pressure drop, faces the inlet and is exposed to fluid first. This allows for a fluid-mechanically favorable flow through the filter device.However, a reversal is also conceivable, in which the first section of the outer surface of the filter element faces the inlet of the housing and the second section of the outer surface of the filter element faces the outlet of the housing.

[0015] Furthermore, it can be provided that the second section of the outer surface of the filter element forms an upstream side of the filter element, and that an outer surface of the drying unit forms an upstream side of the drying unit. This allows for a fluid-mechanically favorable flow through the filter unit.

[0016] Furthermore, the drying unit can be designed to be fully supported by its inner surface contacting the outer surface of the filter element. This provides radial support for the drying unit against the filter element. Additionally, friction between the inner surface of the drying unit and the outer surface of the filter element can provide axial securing of the drying unit to the filter element. This has the advantage of allowing the drying unit to be relatively slim and, for example, the dryer housing to be designed with relatively thin walls.

[0017] Furthermore, it may be advantageous if a first annular gap, radially circumferential to the outside of the drying device, is formed between an outer surface of the filter element and an inner surface of the housing, with the first partial path being guided through this first annular gap. It may also be provided that a second annular gap, radially circumferential to the outside of the filter element and fluidically connected to the first annular gap, is formed radially between the second surface section of the outer surface of the filter element and the inner surface of the housing, with the flow path splitting in the second annular gap into the first partial path and the second partial path, so that during operation of the filter device, liquid is guided along the first partial path through the first annular gap, the drying device, and the filter element, and along the second partial path through the filter element.This indicates a preferred embodiment for the filter device in which a favorable pressure loss can be achieved.

[0018] Furthermore, the drying device may comprise a dryer housing containing the desiccant and two axially opposed cover plates arranged on the dryer housing. The first cover plate may be radially supported by loose contact with an inner surface of the housing. The second cover plate may be axially supported by loose contact with a base surface of the housing adjoining the inner surface. This secures the drying device to the housing. Any axial changes in the length of the drying device, for example, due to aging of the desiccant, can thus be compensated for. In addition, this design allows for easy assembly and disassembly of the drying device on the housing.The first cover disc can, for example, face the inlet of the housing and the second cover disc can face the outlet of the housing.

[0019] The dryer housing can be made of a plastic material. Furthermore, the dryer housing can have axial and / or circumferential support struts extending around the central axis, between which a liquid-permeable mesh is arranged. The mesh can, for example, have a preferred mesh size of 800 µm.

[0020] Advantageously, the filter element comprises a filter material, for example, a pleated star, and two axially opposed end discs arranged on the filter material. The first end disc can be loosely supported against an inner surface of the housing and tightly seal an axial annular opening of the filter element. This prevents direct axial flow through the filter element and ensures that, during operation of the filter device, liquid flows completely over the first section of the outer surface of the filter element and / or the outer surface of the drying device. Furthermore, it can be advantageous if the second end disc is loosely supported against a base surface of the housing adjoining the inner surface.The first end disk can, for example, face the inlet of the housing and the second end disk the outlet of the housing. This defines a preferred filter element. The end disks can each be electrically conductive. Furthermore, the filter element can have an inner frame that supports the filter material radially from the inside. This inner frame can also be electrically conductive.

[0021] With regard to the housing of the filter device, it should be noted that the housing of the filter device is expediently designed in multiple parts. The multi-part housing of the filter device can comprise a cover part, on which the housing inlet is provided, a cylindrical intermediate part having a circumferential wall whose inner surface facing the central axis forms the aforementioned inner surface of the housing, and a bottom part, on which the housing outlet is provided. The bottom part and the intermediate part can be formed as one piece, and the cover part as a separate piece. Alternatively, the intermediate part and the cover part can be formed as one piece, and the bottom part as a separate piece. In this case, it is expedient if the cover part or theThe base section is designed to tightly seal a housing opening defined by the intermediate section, through which the filter element and drying unit, in particular, can be inserted into or removed from the housing. The housing of the filter unit can be made of either aluminum or plastic.

[0022] According to a further fundamental concept of the invention, an immersion cooling system is provided for a vehicle, comprising a traction battery with energy storage cells and a cooling circuit in which liquid circulates. The energy storage cells of the traction battery are fluidically integrated into the cooling circuit and, during operation of the immersion cooling system, are directly surrounded by the liquid, thus enabling direct heat transfer from the energy storage cells to the liquid. The proposed immersion cooling system is equipped with at least one filter device as described above and is further fluidically integrated into the cooling circuit of the traction battery, allowing the liquid to be filtered and dried during operation of the immersion cooling system.This specifies a preferred immersion cooling system for a vehicle traction battery, which includes at least one filter device according to the invention. Due to the advantageous properties of the filter device according to the invention presented above, in particular the reduced pressure loss, the cooling of the traction battery by means of the proposed immersion cooling system can be carried out comparatively efficiently.

[0023] According to a further fundamental concept of the invention, an advantageous use of a filter device, designed according to the preceding description, is proposed in an immersion cooling system. In particular, the immersion cooling system can be configured as an immersion cooling system arranged in a vehicle for the direct cooling of energy storage cells of a traction battery provided in the vehicle. This indicates an advantageous use of a filter device according to the invention. It is clear to those skilled in the art that, in the aforementioned immersion cooling, the components to be cooled, in particular the energy storage cells of the traction battery, are directly surrounded by a coolant for improved heat dissipation. The coolant can be a dielectric coolant, in particular a dielectric liquid mixture.

[0024] In summary, the present invention preferably relates to a filter device comprising a housing through which a liquid flow path extends, a filter element for filtering the liquid arranged in the housing, and a drying device arranged in the housing with a desiccant for drying the liquid. A key aspect of the invention is that the drying device radially surrounds the filter element, such that the outer surface of the filter element has a first surface section covered by the drying device and a second surface section extending axially beyond the filter element, and that the flow path in the housing is divided into two sub-paths. The invention relates in particular to an immersion cooling system for a vehicle with such a filter device, and further, in particular, to the use of such a filter device.

[0025] Further important features and advantages of the invention will become apparent from the dependent claims, the drawings and the associated description of the figures based on the drawings.

[0026] It is understood that the features mentioned above and those to be explained below can be used not only in the combination specified, but also in other combinations or on their own, without leaving the scope of the present invention.

[0027] Preferred embodiments of the invention are shown in the drawings and are explained in more detail in the following description, wherein identical reference numerals refer to identical or similar or functionally identical components.

[0028] They show, schematically, each one Fig. 1 a longitudinal sectional view of a preferred embodiment of a filter device according to the invention and Fig. 2 a perspective view of a drying device of the filter device from Fig. 1.

[0029] The Fig. Figure 1 shows a filter device designated as a whole by reference numeral 1, which may, for example, be integrated into a cooling circuit of an immersion cooling system (not illustrated) for a traction battery of a vehicle.

[0030] The fluid circulating through the cooling circuit, in this case, for example, a dielectric coolant, carries foreign particles as well as dissolved or free water during operation. In particular, the carried water can lead to long-term damage such as corrosion to the components fluidly integrated into the cooling circuit. Filter unit 1 is therefore designed to filter and dry the coolant.

[0031] The use of the filter device 1 in the cooling circuit causes a certain unavoidable pressure drop due to internal flow resistances, which, however, is significantly lower in the present case due to the inventive design of the filter device 1 described below than with conventional filter devices.

[0032] Specifically, the filter device 1 is designed to have a hollow cylindrical housing 2 extending along a central axis 10 and enclosing a volume 11 through which the liquid flows along a flow path 12 (only partially indicated) from an inlet 13 of the housing 2 to an outlet 14 of the housing 2. The housing 2 is made of an aluminum alloy or a plastic material and is expediently designed in multiple parts. It has a substantially round lid 5 on which the aforementioned inlet 13 of the housing 2 is arranged in a central position. Furthermore, the housing 2 has a cup-shaped lower part consisting of a round hollow cylindrical intermediate part 6 and a substantially round bottom part 8 integrally arranged thereon.The intermediate section 6 has a circumferential wall 7 surrounding the central axis 10, which defines an inner housing surface 3 of the housing 2 facing the central axis 10 and an outer housing surface opposite the inner housing surface 3, demarcating the housing 2 from its surroundings. Furthermore, the outlet 14 of the housing 2 is arranged in a central position on the base section 8. The outlet 14 of the housing 2 extends axially into the volume 11, forming an inner nozzle 41. The base section 8 has a housing surface 39 facing the volume 11.

[0033] In Fig. 1. It can also be seen that the intermediate part 6 defines a housing opening 9 of the housing 2 on an end face facing away from the bottom part 8, which in this case is tightly closed by the cover part 5 and through which, when the cover part 5 is removed, components of the filter device 1, in particular a filter element 15 and a drying device 16, can be axially inserted into the volume 11 of the housing 2 in the direction of a mounting direction 37 running parallel to the central axis 10 or axially removed in a direction opposite to the mounting direction 37.

[0034] The filter assembly 1 further comprises the aforementioned filter element 15, which has a hollow cylindrical shape and is designed for filtering the liquid. For this purpose, the filter element 15 is arranged coaxially to the central axis 10 within the volume 11 of the housing 2, allowing liquid to flow through it. The filter element 15 is further composed of a filter material 31, for example, a pleated star, and two essentially round end plates 32, 33, the latter being arranged axially opposite each other on the filter material 31. The filter material 31 and / or the end plates 32, 33 define an outer surface 18 of the filter element 15 radially on the outside. Furthermore, the filter material 31 defines an inner surface of the filter element 15 radially on the inside, on which an inner frame 40 of the filter element 15, supporting the filter material 31, may be provided.The first end disk 32 of these end disks 32, 33, when the filter element 15 is installed, is associated with the inlet 13 of the housing 2 and tightly seals an axial annular opening 34 of the filter element 15 facing the inlet 13. This prevents flow through the filter element 15 in the axial direction and ensures that the filter element 15 and the aforementioned drying device 16 are radially permeated by liquid during operation of the filter device 1. Furthermore, the first end disk 32 can be loosely supported in a centering effect on the inner surface 3 of the housing 2. The second end disk 33 of these end disks 32, 33, when the filter element 15 is installed, is associated with the outlet 14 of the housing 2 and has a central through-opening 38 for liquid.The second end disk 33 can be loosely supported with a centering effect on the inner nozzle 41 of the outlet 14 of the housing 2, which projects into the volume 11 of the housing 2. Furthermore, it is provided that the second end disk 33 is axially supported loosely in contact with the housing base 39 of the bottom part 8 of the housing 2.

[0035] The aforementioned drying unit 16 of the filter unit 1, which is located in Fig. 1 and Fig. Figure 2 shows the drying device 16, which, like the filter element 15, has a hollow-circular cylindrical shape. Unlike the filter element 15, the drying device 16 serves to dry the liquid. For this purpose, the drying device 16 includes a drying agent 17, which separates the water carried in the liquid from the liquid, a process referred to here as "drying". The drying agent 17 can be formed from zeolites and / or silica gel and may, for example, be stored as a loose bed in the drying device 16.

[0036] The drying device 16 has an outer shell surface 23 and, radially opposite, an inner shell surface 35. The drying device 16 further comprises a dryer housing 28 and two axially opposed cover discs 29, 30 arranged on the dryer housing 28, wherein in Fig. 2 only the first cover disc 29 of these cover discs 29, 30 is shown. In this case, the first cover disc 29 of these cover discs 29, 30, in the installed state of the drying device 16, can be assigned to the inlet 13 of the housing 2 and loosely supported with a centering effect on the inner surface 3 of the housing 2. In Fig. 1 and Fig. Figure 2 also shows that the first cover disc 29 is annular in shape, has a U-shaped cross-section, and possesses an arrangement 29a of several flowable, axial through-openings 29b. The through-openings 29b can each be configured as radially extending slots, the slots having, for example, a maximum opening width oriented transversely to their main direction of extension in the region of the mesh size of a sieve fabric 45 of the drying device 16, for example, 800 µm. Furthermore, the second cover disc 30 of these cover discs 29, 30, in the installed state of the drying device 16, can be associated with the outlet 14 of the housing 2 and loosely axially supported on the housing base 39 of the housing 2, in this case by a pin-like cover foot 30b projecting axially from the cover disc 30. This secures the drying device 16 to the housing 2.Furthermore, it is evident that the second cover disc 30 is annular in design and has a U-shaped cross-section. The aforementioned dryer housing 28, which can be manufactured as an injection-molded part from a plastic material, has axially extending support struts 44a and two ring support struts 44b, each extending circumferentially 43 around the central axis 10 and provided on opposite end faces of the dryer housing 28. Radially open, liquid-permeable windows 46 are defined between the support struts 44a and the two ring support struts 44b. The dryer housing 28 also has a liquid-permeable screen fabric 45, which is fixed to the support struts 44a and the ring support struts 44b and completely spans the windows 46 of the dryer housing 28. The sieve fabric 45 has an outer layer 45a and an inner layer 45b, which define an absorption volume 45d between them in which the desiccant 17 is stored.The outer layer 45a and / or the inner layer 45b can be fixed to the cover discs 29, 30 and / or the ring support struts 44b by their axial end faces 45c arranged on the cover discs 29, 30, so that the receiving volume 45d of the sieve fabric 45 is sealed against the volume 11 of the housing 2. Furthermore, it should be noted that the cover discs 29, 30 can each be axially mounted and fixed to an end-face ring support strut 44b.

[0037] Furthermore, in Fig.Figure 1 shows that the drying device 16, when installed, is arranged coaxially to the central axis 10 within the volume 11 of the housing 2 and is axially fitted over the filter element 15. The diameter of the inner surface 35 of the drying device 16 is advantageously matched to the diameter of the outer surface 18 of the filter element 15 or to the outer diameter of the filter element 15, such that the drying device 16 can be axially slid onto the filter element 15 during assembly, for example manually in the assembly direction 37, and / or axially pulled off the filter element 15 in the opposite direction during disassembly.The drying device 16 could also be permanently fixed to the outside of the filter element 15, for example by fixing its cover discs 29, 30 to the outer surface 18 of the filter element 15, so that the drying device 16 and the filter element 15 form a permanent assembly that can be provided, for example, as a spare part for the proposed filter device 1. Furthermore, in the illustrated installation state, a first annular gap 26 is formed radially around the outside of the drying device 16 between the outer surface 23 of the drying device 16 and the inner surface 3 of the housing 2.

[0038] To ensure that the total pressure drop generated by the filter unit 1 during operation is comparatively low, as mentioned above, the filter element 15 is designed to project axially beyond the drying unit 16 in the direction of the central axis 10. This divides the outer surface 18 of the filter element 15 into a first circumferential surface section 19, which is covered by the drying unit 16, and a second circumferential surface section 20, which is not covered by the drying unit 16. A second annular gap 27 is defined radially between the second surface section 20 of the outer surface 18 of the filter element 15 and the inner surface 3 of the housing 2. This annular gap 27 surrounds the filter element 15 radially and is fluidically connected to the first annular gap 26.

[0039] Furthermore, the first, covered outer surface section 19 of the outer surface 18 of the filter element 25 is assigned to the outlet 14 of the housing 2, and the second outer surface section 20 of the outer surface 18 of the filter element 15 is assigned to the inlet 13 of the housing 2. Thus, the second outer surface section 20 of the outer surface 18 of the filter element 15 and the outer surface 23 of the drying device 16 each form an inflow side.

[0040] This arrangement can be achieved in particular by arranging the second end disk 33 of the filter element 15 and the second cover disk 30 of the drying device 16 at substantially the same axial height, so that they are, for example, radially opposite each other, and furthermore by having the filter element 15 have an axial filter element height 24 to be determined along the central axis 10 and the drying device 16 have an axial drying device height 25 to be determined along the central axis 10, wherein the axial filter element height 24 is greater than the axial drying device height 25.It is also conceivable that the filter element height 24 is equal to the drying device height 25, wherein, in contrast to the previous embodiment, the drying device 16 and the filter element 15 are arranged axially offset from each other to generate the axial overhang of the filter element 15 over the drying device 16, with the second end disk 33 of the filter element 15 and the second cover disk 30 of the drying device 16.

[0041] By dividing the outer surface 18 of the filter element 15 into the first, covered surface section 19 and the second, uncovered surface section 20, the flow path 12 in the volume 11 of the housing 2 is separated into two distinct partial paths 21, 22 in the second annular gap 27. The first partial path 21 of these two partial paths 21, 22 passes through the first annular gap 26, over the outer surface 23 of the drying device 16 facing the inner surface 3 of the housing 2, through the drying device 16, and over the first surface section 19 of the outer surface 18 of the filter element 15, through the filter element 15. The second partial path 22 of these two partial paths 21, 22 is only passed through the filter element 15 via the second lateral surface section 20 of the outer lateral surface 18 of the filter element 15.

[0042] This results in a situation advantageous from a fluid mechanics perspective during the operation of the filter device 1: liquid flows along the first path 21 through the drying device 16 and through the filter element 15, where it is filtered and dried, and liquid flows along the second path 22 exclusively through the filter element 15 and is filtered. The first pressure drop component that occurs across the second path 22 (only the filter element 15 is flowed through) is significantly lower than the second pressure drop component that occurs across the first path 21 (drying device 16 and filter element 15 are flowed through).This has the advantage that the volume of liquid flowing through the filter device 1 during operation can be completely filtered with a comparatively small overall pressure drop, which is composed in particular of the first pressure loss component and the second pressure loss component, and a predetermined proportion of the liquid volume sufficient for the operation of the filter device 1 can be dried. QUOTES INCLUDED IN THE DESCRIPTION

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

[0000] DE 10 2019 122 034 A1

[0002]

Claims

[1] Filter device (1) for filtering and drying a liquid, in particular an oil filter, comprising - a hollow cylindrical housing (2) extending along a central axis (10) and enclosing a volume (11) through which the fluid flows along a flow path (12) from an inlet (13) of the housing (2) to an outlet (14) of the housing (2), - a filter element (15) for filtering the liquid, which is arranged in the volume (11) of the housing (2), characterized by , that - the filter device (1) comprises a drying device (16) arranged in the volume (11) and shaped in a hollow cylindrical form, with a drying agent (17) for drying the liquid, - the drying device (16) radially surrounds an outer shell surface (18) of the filter element (15), such that the outer shell surface (18) of the filter element (15) has a first circumferential shell surface section (19) covered by the drying device (16) and a second circumferential shell surface section (20) projecting beyond the drying device (16) in the direction of the central axis (10), - the flow path (12) in the volume (11) of the casing (2) is divided into two sub-paths (21, 22), - the first partial path (21) of these two partial paths (21, 22) is guided through the drying device (16) via an outer shell surface (23) of the drying device (16) and through the first shell surface section (19) of the outer shell surface (18) of the filter element (15) through the filter element (15), so that during operation of the filter device (1) liquid flows along the first partial path (21) through the drying device (16) and through the filter element (15), - the second partial path (22) of these two partial paths (21, 22) is routed through the filter element (15) via the second lateral surface section (20) of the outer lateral surface (18) of the filter element (15), so that during operation of the filter device (1) liquid flows along the second partial path (22) exclusively through the filter element (15). [2] Filter device (1) according to claim 1, characterized by , that - an area ratio is provided between the first lateral surface section (19) of the outer lateral surface (18) of the filter element (15) and the second lateral surface section (20) of the outer lateral surface (18) of the filter element (15), - the area ratio of the first lateral surface section (19) to the second lateral surface section (20) is in the range of 10:1 to 1:1, especially 6:

1. [3] Filter device (1) according to claim 1 or 2, characterized by , that - the filter element (15) has an axial filter element height (24) extending along the central axis (10), - the drying device (16) has an axial drying device height (25) extending along the central axis (10), - the axial filter element height (24) is greater than or equal to the axial drying device height (25). [4] Filter device (1) according to one of the preceding claims, characterized by , that - the first lateral surface section (19) of the outer lateral surface (18) of the filter element (25) is arranged along the flow path (12) closer to the outlet (14) of the housing (2) than to the inlet (13) of the housing (2), and / or - the second lateral surface section (20) of the outer lateral surface (18) of the filter element (15) is located along the flow path (12) closer to the inlet (13) of the housing (2) than to the outlet (14) of the housing (2). [5] Filter device (1) according to one of the preceding claims, characterized by , that - the second lateral surface section (20) of the outer lateral surface (18) of the filter element (15) forms an upstream side of the filter element (15), - the outer shell surface (23) of the drying device (16) forms an upstream side of the drying device (16). [6] Filter device (1) according to one of the preceding claims, characterized by , that - the drying device (16) is fully supported over its inner surface (35) by contacting the outer surface (18) of the filter element (15). [7] Filter device (1) according to one of the preceding claims, characterized by , that - a first annular gap (26) is formed radially between an outer surface (23) of the drying device (16) and an inner surface (3) of the housing (2), which circumferentially surrounds the drying device (16) radially outside, - the first partial path (21) is led through the first annular gap (26), - radially between the second outer surface section (20) of the outer surface (18) of the filter element (15) and the inner surface (3) of the housing (2) a second annular gap (27) is formed, which surrounds the filter element (15) radially and is fluidically connected to the first annular gap (26), - the flow path (12) splits in the second annular gap (27) into the first partial path (21) and the second partial path (22), so that during operation of the filter device (1) liquid is guided along the first partial path (21) through the first annular gap (26), the drying device (16) and through the filter element (15) and along the second partial path (22) through the filter element (15). [8] Filter device (1) according to one of the preceding claims, characterized by , that - the drying device (16) comprises a dryer housing (28) containing the drying agent (17) and two axially opposed cover discs (29, 30) arranged on the dryer housing (28), - the first cover disc (29) of these cover discs (29, 30) is supported radially in loose contact with an inner housing surface (3) of the housing (2), - the second cover disc (30) of these cover discs (29, 30) is loosely axially supported on a housing base surface (4) of the housing (2) adjoining the inner housing surface (3). [9] Filter device (1) according to any one of the preceding claims, characterized by , that - the filter element (15) has a filter material (31) and two axially opposite end disks (32, 33) arranged on the filter material (31), - the first end disk (32) of these end disks (32, 33) is loosely supported on an inner housing surface (3) of the housing (2) and tightly seals an axial ring opening (34) of the filter element (15), and / or - the second end disk (33) of these end disks (32, 33) is loosely supported by contact with a housing base surface (4) of the housing (2) adjoining the inner housing surface (2). [10] Immersion cooling system for a vehicle, - with a traction battery with energy storage cells, - with a cooling circuit in which liquid circulates, - wherein the energy storage cells of the traction battery are fluidically integrated into the cooling circuit and are directly surrounded by the liquid during operation of the immersion cooling system, so that a direct heat transfer from the energy storage cells to the liquid is realized, - with at least one filter device (1) designed according to one of the preceding claims 1 to 9 and fluidically integrated into the cooling circuit of the traction battery, so that liquid can be filtered and dried during operation of the immersion cooling system. [11] Use of a filter device (1) according to any one of the preceding claims 1 to 9, in an immersion cooling system, in particular an immersion cooling system arranged in a vehicle for the direct cooling of energy storage cells of a traction battery of the vehicle provided in the vehicle.

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