Degassing Unit and Electronics Housing, in Particular Battery Housing

Abstract

A degassing unit for an electronics housing has a base body with gas passage opening and is connectable fluid-tightly to a rim of a pressure compensation opening of the electronics housing. A semipermeable membrane for covering the pressure compensation opening enables passage of gaseous media from an environment into the electronics housing interior and vice versa but prevents passage of liquids and solids. A membrane support device, arranged at an interior side of the base body facing the electronics housing interior, engages across the gas passage opening and is positioned at a first distance to the semipermeable membrane. A separation lattice with lattice openings is arranged at the interior side of the base body at a second larger distance to the semipermeable membrane and completely engages across the gas passage opening. A surface area spanned by the separation lattice is larger than a cross section of the gas passage opening.

Claims

1. A degassing unit for an electronics housing, the degassing unit comprising: a base body configured to be connected fluid-tightly to a rim of a pressure compensation opening of the electronics housing and comprising a gas passage opening, wherein the base body comprises at least one fastening means action region configured to attach the degassing unit to the electronics housing; a semipermeable membrane configured to cover the pressure compensation opening of the electronics housing, wherein the semipermeable membrane enables passage of gaseous media from an environment into an interior of the electronics housing and from the interior of the electronics housing into the environment, and wherein the semipermeable membrane prevents passage of liquid media and/or solids therethrough; a membrane support device arranged at an interior side of the base body facing the interior of the electronics housing in a mounted state of the degassing unit, wherein the membrane support device engages at least partially across the gas passage opening, wherein the membrane support device is positioned at a first distance away from the semipermeable membrane; a separation lattice comprising lattice openings, wherein the separation lattice is arranged at the interior side of the base body at a second distance away from the semipermeable membrane, wherein the second distance is larger than the first distance; wherein the separation lattice completely engages across the gas passage opening; wherein a surface area spanned by the separation lattice is larger than a cross section of the gas passage opening.

2. The degassing unit according to claim 1, wherein the membrane support device is fluid-permeable.

3. The degassing unit according to claim 2, wherein the membrane support device is a lattice section with a plurality of lattice openings.

4. The degassing unit according to claim 1, wherein the separation lattice is connected particle-tightly to the base body.

5. The degassing unit according to claim 1, wherein the lattice openings of the separation lattice have a dimension in at least one extension direction that is smaller than 2.0 mm.

6. The degassing unit according to claim 1, wherein the semipermeable membrane is arranged at the interior side of the base body and is at least partially engaged from behind by the membrane support device.

7. The degassing unit according to claim 1, wherein the separation lattice is bulged cup-shaped in a direction pointing inwardly into the interior of the electronics housing in the mounting state of the degassing unit.

8. The degassing unit according to claim 1, wherein the separation lattice is substantially of a planar configuration.

9. The degassing unit according to claim 1, further comprising at least one spacer which holds the separation lattice at the second distance away from the semipermeable membrane, wherein the at least one spacer is embodied either to project axially inwardly away from the base body or to project axially outwardly away from the separation lattice.

10. The degassing unit according to claim 1, wherein dimensions of lattice openings of the membrane support device are larger than dimensions of the lattice openings of the separation lattice.

11. The degassing unit according to claim 1, wherein the separation lattice and the membrane support device are embodied separate from each other.

12. The degassing unit according to claim 1, wherein the separation lattice and the membrane support device are embodied together as one piece.

13. The degassing unit according to claim 12, wherein the membrane support device is embodied as an axial support bulge of the separation lattice.

14. The degassing unit according to claim 13, wherein the axial support bulge is arranged centrally in relation to the gas passage opening.

15. The degassing unit according to claim 13, wherein the axial support bulge of the separation lattice forms a lattice section of the membrane support device.

16. The degassing unit according to claim 1, further comprising a filter medium supported by the separation lattice, wherein the filter medium comprises a lattice material and/or a nonwoven material.

17. The degassing unit according to claim 16, wherein the filter medium comprises a metallic material or consists of a metallic material.

18. The degassing unit according to claim 1, wherein the separation lattice is non-detachably or detachably connected to the base body.

19. The degassing unit according to claim 18, wherein the separation lattice is detachably snapped onto the base body.

20. The degassing unit according to claim 1, wherein a distance between the separation lattice and the membrane support device in a region of a center of the gas passage opening amounts to at least 0.2 mm.

21. The degassing unit according to claim 1, wherein the fastening means action region of the base body comprises a bore open toward the interior side of the base body and/or an exterior side of the base body.

22. The degassing unit according to claim 1, wherein the separation lattice is a sheet metal part.

23. The degassing unit according to claim 22, wherein the separation lattice comprises at least one push-through opening aligned with at least one blind bore of the base body.

24. The degassing unit according to claim 1, wherein the separation lattice comprises at least one fastening tab, wherein the fastening tab is configured to connect the separation lattice immediately to a housing wall of the electronics housing.

25. The degassing unit according to claim 1, further comprising a covering hood connected to an exterior side to the base body.

26. The degassing unit according to claim 25, wherein the covering hood comprises at least one venting opening.

27. The degassing unit according to claim 25, wherein the covering hood is fastened by a locking element to the base body.

28. The degassing unit according to claim 1, further comprising a housing seal circumferentially surrounding the gas passage opening of the base body at the interior side of the base body.

29. The degassing unit according to claim 1, further comprising an emergency degassing spike arranged externally in relation to the semipermeable membrane and extending in an axial direction toward the semipermeable membrane, wherein the emergency degassing spike comprises a tip and the tip, in a state of rest, is positioned at a predetermined distance away from an outer membrane surface of the semipermeable membrane, wherein the outer membrane surface is facing away from the interior of the electronic housing.

30. The degassing unit according to claim 29, wherein the emergency degassing spike is formed at the base body or at a covering hood connected to the base body.

31. An electronics housing comprising a housing wall comprising a pressure compensation opening, wherein the pressure compensation opening is closed by a degassing unit according to claim 1.

32. The electronics housing according to claim 31, wherein the degassing unit is connected by at least one fastening means to the housing wall, wherein the fastening means engages the fastening means action region of the base body of the degassing unit, and wherein the separation lattice is secured between the housing wall of the electronics housing and the base body of the degassing unit.

33. The electronics housing according to claim 32, wherein the separation lattice is indirectly secured with form fit and/or friction fit between the housing wall of the electronics housing and the base body of the degassing unit.

34. The electronics housing according to claim 32, wherein the separation lattice is directly secured with form fit and/or friction fit between the housing wall of the electronics housing and the base body of the degassing unit.

35. The electronics housing according to claim 32, wherein the separation lattice is connected immediately to the housing wall of the electronics housing by the at least one fastening means, wherein the at least one fastening means is a metallic fastening element guided through an opening of at least one fastening tab of the separation lattice.

36. The electronics housing according to claim 31, wherein the electronics housing is a battery housing configured to accommodate battery cells.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0060] Further advantages result from the following drawing description. In the drawings, embodiments of the invention are illustrated. The drawings, description, and claims contain numerous features in combination. A person of skill in the art will consider the features expediently also individually and combine them to expedient further combinations.

[0061] FIG. 1 shows an isometric section view of a degassing unit according to the invention according to a first embodiment.

[0062] FIG. 2 shows a further isometric section view of the degassing unit according to the invention according to the first embodiment.

[0063] FIG. 3 shows an isometric view of a degassing unit according to the invention according to a second embodiment.

[0064] FIG. 4 shows an isometric section view of the degassing unit according to the invention according to the second embodiment.

[0065] FIG. 5 shows a further isometric view of the degassing unit according to the invention according to the second embodiment from the exterior.

[0066] FIG. 6 shows an isometric view of a degassing unit according to the invention according to a third embodiment.

[0067] FIG. 7 shows an isometric section view of the degassing unit according to the invention according to the third embodiment.

[0068] FIG. 8 shows detail A of FIG. 7.

[0069] FIG. 9 shows an isometric view of a degassing unit according to the invention according to a fourth embodiment.

[0070] FIG. 10 shows an isometric section view of a degassing unit according to the invention according to the fourth embodiment.

[0071] FIG. 11 shows an isometric section view of the degassing unit according to the invention according to a fifth embodiment.

DESCRIPTION OF PREFERRED EMBODIMENTS

[0072] In the Figures, same or same type components are identified with same reference characters. The Figures show only examples and are not to be understood as limiting. Features or feature combinations which are disclosed in connection with a certain embodiment are intended to also apply—if not explicitly excluded—also onto other embodiments.

[0073] All Figures show the degassing unit 10 according to the invention in an installed state with a section of a wall 4 of an electronics housing, in particular for a battery, in particular for a traction battery of a motor vehicle.

[0074] In FIG. 1 and FIG. 2, a first embodiment of the degassing unit 10 according to the invention is illustrated in an isometric section illustration. It comprises a base body 1 which is connected by a screw connection at the exterior side to a rim of a pressure compensation opening of an electronics housing, in particular of a battery housing of a traction battery. The screw connection comprises a plurality of screws 3 as well as corresponding fastening means action regions 11 of the base body into which the screws are screwed. The screws 3 extend respectively through through bores 41 of the wall 4 of the electronics housing. The degassing unit 10 is mounted at the exterior side at the electronics housing and is screwed on from the interior side. For fluid-tight sealing action of the base body 1 of the degassing unit 10 with the wall 4 of the electronics housing, the housing seal 7 is provided which is compressed by the sealing pretensioning force applied by the screws 3. The housing seal 7 is arranged in a seal receiving groove 16 of the base body 1 and is secured therein by a “bulgy” cross section region so that it does not drop out during mounting.

[0075] The base body 1 has in addition a gas passage opening 15 through which a pressure compensation between electronics housing interior and the environment as well as in reverse can take place.

[0076] Moreover, the degassing unit 10 comprises a semipermeable membrane 6 which is permeable for gaseous fluids, but prevents passage of solid bodies and liquids. Preferably, the membrane is embodied as a porous PTFE film. The semipermeable membrane 6 is connected fluid-tightly to the base body 1 at the interior side 17 around the gas passage opening 15 of the base body 1, preferably welded or glued, namely to the rim 151.

[0077] The gas passage opening 15 or the membrane 6 is covered further by a fluid-permeable membrane support device 2 which is positioned at a first distance away from the membrane 6. The membrane support device 2 has a plurality of lattice stays 21 between which a plurality of lattice openings 24 are present. The membrane support device 2 in the present embodiment is embodied as a stamped sheet metal part.

[0078] At its exterior side 18, a covering hood 5 is connected to the base body 1 which comprises at least one venting opening 51 and which is configured to provide protection for the sensitive membrane 6 so that the latter cannot be damaged from the exterior either by foreign bodies, for example, pointed objects such as screwdrivers or the like, or by means of high-pressure cleaners and/or steam cleaners. Construction and dimensioning of the covering hood contribute thus significantly to a high IP protection class.

[0079] Moreover, the degassing unit 10 comprises a separation lattice 8 that comprises a plurality of openings 81. The separation lattice 8 is present at a second distance away from the membrane 6 that is larger than the first distance at which the membrane support device 2 is positioned. The openings 81 of the separation lattice 8 are moreover smaller than the openings 24 of the membrane support device 2 and provide an ingress protection so that long and pointed objects (for example, wires, screwdrivers or the like) cannot be introduced into the electronics housing interior. The separation lattice 8 is embodied as a bulged cup 82 that bulges in an inwardly oriented direction. By means of the separation lattice 8, particles which in case of a cell defect will be released from individual or a plurality of battery cells can be retained in the housing interior. The dimensions of the lattice openings 81 of the separation lattice 8 are to be selected such that a proportion of a particle fraction as large as possible is retained thereby in order to prevent that they reach the environment. The dimensions of the lattice openings 81 of the separation lattice are selected such, for example, that a certain mass proportion of the particles, for example, >75%, can be retained. The cup shape of the separation lattice 8 enlarges the surface area that is available for particle separation in comparison to a planar embodiment and reduces therefore the tendency of the separation lattice 8 to block in case of strongly particle-loaded gas flows. An enlarged surface of the separation lattice 8 has moreover the advantage that thermal peaks are distributed across a larger surface area, which reduces the risk of thermally caused structural damages.

[0080] According to the illustrated embodiment, the separation lattice 8 is connected in a particle-tight way to the base body 1 in that it is clamped sandwich-like between the wall 4 of the electronics housing and the base body 1. For facilitating assembly of the degassing unit 10, the separation lattice 8 can be additionally at least prefixed in relation to the base body 1; for this purpose, all connecting types (for example, gluing) that appear suitable to a person of skill in the art are conceivable.

[0081] The base body 1 comprises moreover an emergency degassing spike 19. The latter extends toward the membrane 6 and is arranged in the state of rest (no differential pressure load) at a predetermined distance away from the outer membrane surface 61. Under pressure load (relative inner pressure), the membrane 6 will bulge in the direction toward the exterior space and upon reaching a limit pressure will contact the tip 191 of the emergency degassing spike 19. Due to its tip 191, the emergency degassing spike 19 then produces a targeted weakening of the membrane 6 so that the latter ruptures. This serves for securing an emergency degassing function that reacts as quickly as possible which is important in order to ensure in case of a sudden inner pressure increase in the electronics housing that the housing structure remains intact. Due to a variation of the distance of the tip 191 of the emergency degassing spike 19 relative to the membrane surface 61, the emergency degassing pressure is adjustable.

[0082] According to the second embodiment illustrated in FIG. 3 to FIG. 5, the membrane support device 2 is embodied as one piece together with the separation lattice 8. The degassing unit 10 is arranged at the interior side at the wall 4 of the electronics housing and is screwed on from the exterior.

[0083] The separation lattice 8 comprises an engagement region 84 which engages the base body 1 radially outwardly in circumferential direction. In the engagement region 85, the detachable fastening of the separation lattice 8 to the base body 1 by snap-on means 84 of the separation lattice 8 is realized which are snapped into respective corresponding snap receptacles of the base body 1. The engagement of the separation lattice 8 extending circumferentially in this way increases the stiffness of the separation lattice 8, on the one hand, and contributes to an improved particle seal-tightness, on the other hand. The membrane support device 2 according to this embodiment is formed as an axial bulge 83 or depression of the separation lattice 8. The membrane support device 2 is provided by an axially displaced fluid-permeable lattice section of the separation lattice 8 which is arranged approximately centrally relative to the gas passage opening 15 and is present at a first distance away from the membrane 6 while the sections of the separation lattice 8 which are not axially displaced are positioned at a second distance away from the membrane 6 that is larger than the first distance. This embodiment has the decisive advantage that the separation lattice 8 with integrated membrane support device 2 can be produced by a single process (for example, stamping and shaping) and that the mounting expenditure is minimized because only one mounting step (snapping on the separation lattice 8) is required. The base body 1 has moreover a plurality of spacers 12 which extend away inwardly in axial direction and on which the separation lattice 8 is resting in order to keep the latter at the predetermined second distance away from the membrane 6. The spacers 12 are arranged circumferentially distributed about the gas passage opening 15 in order to support the separation lattice 8 as uniformly as possible. In an embodiment that is not illustrated, the spacers can also be formed at the separation lattice 8 and extend in radial direction outwardly in order to rest on the base body 1.

[0084] FIG. 5 shows the degassing unit 10 according to the invention in the mounted state from the exterior without mounted covering cap. With respect to the screw connection and sealing action, the second embodiment corresponds to the first embodiment described above.

[0085] In FIG. 6 to FIG. 9, a third embodiment of the degassing unit 10 according to the invention is illustrated. Functionally, the latter corresponds to the first and second embodiments described above so that only the differences will be explained. The main difference in comparison to the second embodiment resides in the separate embodiment of the separation lattice 8 and of the membrane support device 2. The membrane support device 2 is embodied as a part of the base body 1 and connected thereto by material fusion, in particular welded, and comprises a lattice stay structure 21 that is in particular of a honeycomb shape between which the lattice openings 24 are present. The shape of the lattice stay structure 21 can also deviate from the honeycomb shape in embodiments that are not illustrated. The membrane support device 2 is arranged again at a first distance away from the membrane 6. An embodiment as one piece together with the base body 1 has the advantage that the membrane support device 2 can be produced (for example, by injection molding) together with the base body 1. The membrane support device 2 can be comprised of the same material as the support body 1, for example, of a thermoplastic plastic material, for example, of polypropylene, polybutylene terephthalate or polyamide, each comprising reinforcement fibers, in particular glass fibers, and can therefore be welded without problems to the base body 1. The separation lattice 8 which is of a planar configuration (no bulging or depression) is detachably connected to the base body 1. In regard to the function of the spacers 12 and the attachment of the separation lattice 8 in the engagement region 85 with the base body 1, reference is being had to the explanations in regard to the second embodiment. In FIG. 8, the detachable connection of the separation lattice 8 to the base body 1 by means of snap means 84 of the separation lattice 8, which engage in corresponding snap receptacles 13 of the base body 1, is shown as detail A.

[0086] A fourth embodiment of the degassing unit 10 according to the invention is illustrated in FIG. 9 and FIG. 10. It corresponds substantially to the third embodiment but differs in the configuration of the separation lattice 8. The separation lattice 8 supports with the support lattice stays 86 a filter medium 9 which covers the openings 81 which are significantly larger in the fourth embodiment. The filter medium 9 comprises a wire lattice which defines the effective minimal opening cross section. As an alternative or in addition, the filter medium can comprise also a nonwoven material which in particular can be present at the exterior side adjoining the wire lattice, wherein the effective minimal opening cross section is then determined by a pore size of the nonwoven. This embodiment has the advantage that by the use of a separate filter medium 9 significantly smaller effective opening cross sections can be realized so that also finer particle fractions or a larger gravimetric proportion of the total particle fraction can be separated. The filter medium comprises preferably a metallic material, for example, steel, or consists thereof which is advantageous due to the good thermal resistance. Such wire lattices and/or nonwoven media are available on the market.

[0087] FIG. 11 shows a fifth embodiment of the degassing unit 10 according to the invention. It corresponds substantially to the fourth embodiment according to FIG. 9 and FIG. 10. The difference resides in that the degassing unit 10 according to the fifth embodiment has a fastening tab 87 at its separation lattice 8 which extends radially away from the lattice body of the separation lattice 8. In the fastening tab 87, an opening 871 is present through which a metallic screw is guided, by means of which the separation lattice 8 is connected immediately to the wall 4 of the electronics housing. The technical advantages associated therewith have been discussed in detail in the general part of the description.

LIST OF REFERENCE CHARACTERS

[0088] 10 degassing unit
1 base body
11 fastening means action region
12 spacer
13 snap-on receptacles of the base body
15 gas passage opening
151 rim of the gas passage opening
16 seal receiving groove of the base body
17 interior side of the base body
18 exterior side of the base body
19 emergency degassing spike
191 tip of the emergency degassing spike
2 support device
21 lattice stays
24 lattice openings
3 screw
4 wall of the electronics housing
41 through bore of the wall of the electronics housing
5 covering hood
51 venting openings
6 semipermeable membrane
61 outer membrane surface
7 housing seal
8 separation lattice
81 openings of the separation lattice
82 cup-shaped bulge of the separation lattice
83 axial support bulge of the separation lattice
84 snap-on means of the separation lattice
85 engagement region of the separation lattice
86 support lattice stays of the separation lattice
87 fastening tab of the separation lattice
871 opening of the fastening tab
9 filter medium