Battery Degassing Unit and Battery Housing

Abstract

A battery degassing unit for a battery housing has a base body that has a gas passage opening and is to be connected fluid-tightly to a pressure compensation opening of the battery housing. A first filter covers the gas passage opening at an inner side of the base body. The first filter is a separation grid with first grid openings. A second filter is a separation grid arranged between first filter and inner side of the base body and has second grid openings. The base body has fastening regions for fastening the battery degassing unit to the battery housing. One of the first and second filters completely engages across the gas passage opening. One of the first and second filters is a corrugated filter so that a length extension in a stretched state in at least one direction is at least 1.3 times as large as in a corrugated state.

Claims

1. A battery degassing unit for a battery housing, the battery degassing unit comprising: a base body configured to be connected fluid-tightly to a rim of a pressure compensation opening of the battery housing and comprising at least one gas passage opening; a first filter covering the gas passage opening at an inner side of the base body, wherein the first filter is configured as a separation grid and comprises a plurality of first grid openings; a second filter configured as a separation grid, wherein the second filter is arranged between the first filter and the inner side of the base body and comprises a plurality of second grid openings; wherein at least one of the first filter and the second filter completely engages across the gas passage opening; wherein the base body comprises at least one fastening means region of action configured to fasten the battery degassing unit to the battery housing; wherein at least one of the first filter and the second filter is a corrugated filter so that a length extension in a stretched state of the corrugated filter in at least one direction is at least 1.3 times as large as in a corrugated state of the corrugated filter.

2. The battery degassing unit according to claim 1, wherein the corrugated filter is surrounded at least in sections thereof by side walls and the side walls cover lateral openings of the corrugated filter, wherein the lateral openings are open toward the battery housing.

3. The battery degassing unit according to claim 2, wherein the side walls comprise openings enabling at least a passage of gas.

4. The battery degassing unit according to claim 2, wherein the side walls at least in sections thereof are formed at the first filter and/or at the second filter.

5. The battery degassing unit according to claim 2, wherein the side walls at least in sections thereof are formed at the base body.

6. The battery degassing unit according to claim 1, wherein the corrugated filter comprises folds arranged in parallel to each other, wherein the folds comprise fold edges arranged parallel to the gas passage opening.

7. The battery degassing unit according to claim 1, wherein the first grid openings are configured to separate larger particles and the second grid openings are configured to separate smaller particles that are smaller than the larger particles.

8. The battery degassing unit according to claim 1, further comprising a semipermeable membrane configured to enable a passage of gaseous media from an environment into the battery housing and in reverse and further configured to prevent a passage of liquid media and/or solids, wherein the semipermeable membrane is arranged adjacent to the second filter so as to face toward an outer side of the battery degassing unit.

9. The battery degassing unit according to claim 8, wherein the second filter forms a membrane support device engaging at least partially across the gas passage opening.

10. The battery degassing unit according to claim 8, wherein the semipermeable membrane is located at the inner side of the base body and is at least partially engaged from behind by the second filter.

11. The battery degassing unit according to 8, further comprising an emergency degassing spike that extends externally in an axial direction toward the semipermeable membrane, wherein the emergency degassing spike comprises a tip positioned in a rest state at a predetermined distance from an outer membrane surface of the semipermeable membrane.

12. The battery degassing unit according to 11, wherein the emergency degassing spike is formed at the base body or at a cover hood of the battery degassing unit.

13. The battery degassing unit according to claim 1, wherein the first filter is connected particle-tightly to the base body.

14. The battery degassing unit according to claim 13, wherein a surface area that is spanned by the first filter is larger than a cross section of the gas passage opening.

15. The battery degassing unit according to claim 1, wherein a surface area that is spanned by the first filter is larger than a cross section of the gas passage opening.

16. The battery degassing unit according to claim 1, wherein dimensions of the first grid openings in at least one direction of extension of the first grid openings are smaller than 3.0 mm.

17. The battery degassing unit according to claim 1, wherein dimensions of the second grid openings in at least one direction of extension of the second grid openings are smaller than dimensions of the first grid openings.

18. The battery degassing unit according to claim 1, wherein the first filter comprises a filter medium comprising a grid material and/or a nonwoven material.

19. The battery degassing unit according to claim 18, wherein the grid material is a wire mesh.

20. The battery degassing unit according to claim 18, wherein the filter medium comprises, or is comprised of, a metallic material.

21. The battery degassing unit according to claim 1, wherein the first filter is connected to the second filter.

22. The battery degassing unit according to claim 21, wherein the first filter is welded to the second filter or is snapped onto the second filter.

23. The battery degassing unit according to claim 1, wherein a distance between the first filter and the second filter in a region of a center of the gas passage opening amounts to at least 0.2 mm.

24. The battery degassing unit according to claim 1, wherein the first filter is a sheet metal part.

25. The battery degassing unit according to claim 1, wherein the sheet metal part is a stamped sheet metal part.

26. The battery degassing unit according to claim 1, wherein the first filter comprises at least one fastening tab configured to connect the first filter to the base body.

27. The battery degassing unit according to claim 1, wherein a direction in which the second grid openings have a greatest dimension is positioned at an angle to a direction in which the first grid openings have a greatest dimension.

28. The battery degassing unit according to claim 27, wherein the angle amounts to 90°.

29. A battery housing comprising: at least one housing wall comprising a pressure compensation opening; a battery degassing unit according to claim 1 arranged at the at least one housing wall and closing the pressure compensation opening.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0061] Further advantages result from the following drawing description. In the drawings, embodiments of the invention are illustrated. The drawings, the description, and the claims contained 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.

[0062] FIG. 1 shows an isometric section view of a battery degassing unit according to an embodiment of the invention.

[0063] FIG. 2 shows an isometric view of the battery degassing unit according to FIG. 1 viewed from an inner side of a base body.

[0064] FIG. 3 shows a first filter and a second filter of the battery degassing unit according to FIG. 1 in isometric illustration according to a first embodiment of the invention.

[0065] FIG. 4 shows a first filter and a second filter of the battery degassing unit according to FIG. 1 in isometric illustration according to a further embodiment of the invention.

[0066] FIG. 5 shows a plan view of the battery degassing unit according to FIG. 1 viewed from an outer side of the base body with indicated section planes A-A and B-B.

[0067] FIG. 6 shows a longitudinal section of the battery degassing unit according to FIG. 1 along the section plane A-A.

[0068] FIG. 7 shows an enlarged detail X of the longitudinal section according to FIG. 6.

[0069] FIG. 8 shows a longitudinal section of the battery degassing unit according to FIG. 1 along the section plane B-B.

[0070] FIG. 9 shows a longitudinal section of the battery degassing unit according to FIG. 1 along the section plane C-C.

[0071] FIG. 10 shows an isometric section view of a battery degassing unit according to a further embodiment of the invention.

[0072] FIG. 11 shows an isometric view of the battery degassing unit according to FIG. 10 viewed from an inner side of the base body.

[0073] FIG. 12 shows a first filter and a second filter of the battery degassing unit according to FIG. 10 in isometric illustration.

[0074] FIG. 13 shows a plan view of the battery degassing unit according to FIG. 10 viewed from an exterior side of the base body with indicated section planes A-A and B-B.

[0075] FIG. 14 shows a longitudinal section of the battery degassing unit according to FIG. 10 along the section plane A-A.

[0076] FIG. 15 shows an enlarged detail X of the longitudinal section according to FIG. 14.

[0077] FIG. 16 shows a longitudinal section of the battery degassing unit according to FIG. 10 along the section plane B-B.

[0078] FIG. 17 shows a longitudinal section of the battery degassing unit according to FIG. 10 along the section plane C-C.

[0079] FIG. 18 shows an isometric view of a first filter for a battery degassing unit according to the invention.

DESCRIPTION OF PREFERRED EMBODIMENTS

[0080] 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.

[0081] In FIGS. 1 to 9, a first embodiment of the battery degassing unit 10 is illustrated. FIG. 1 shows an isometric section view of the battery degassing unit 10 while in FIG. 2 an isometric view of the battery degassing unit 10 is illustrated viewed from an inner side 17 of a base body 1.

[0082] In FIGS. 3 and 4, a first filter 8 and a second filter 2 of the battery degassing unit 10 according to FIG. 1 are illustrated, respectively, in isometric illustration for two embodiments.

[0083] FIG. 5 shows a plan view of the battery degassing unit 10 according to FIG. 1, viewed from an outer side 18 of the base body 1, with indicated section planes A-A and B-B. FIG. 6 shows a longitudinal section of the battery degassing unit 10 along the section plane A-A and FIG. 7 an enlarged detail X of the longitudinal section according to FIG. 6. FIG. 8 shows a longitudinal section of the battery degassing unit according to FIG. 1 along the section plane B-B and FIG. 9 a longitudinal section of the battery degassing unit according to FIG. 1 along the section plane C-C.

[0084] The battery degassing unit 10 comprises a base body 1 which is connected by a screw connection externally to a rim of a pressure compensation opening of a battery housing, in particular of a battery housing of a traction battery. The screw connection comprises a plurality of screws (not illustrated) as well as corresponding fastening means regions of action 11 of the base body in which the screws are screwed in. The screws can extend respectively through the through bores of the wall 4 of the battery housing. The battery degassing unit 10 is mounted externally at the battery housing and is screw-connected from the inner side. For fluid-tight sealing of the base body 1 of the battery degassing unit 10 with the wall 4 of the battery housing, the housing seal 7 is provided which is compressed by the sealing pretensioning force that is applied by the screws. The housing seal 7 is arranged in a seal receiving groove 16 of the base body 1 and is held therein by a “bulging” cross section region so that it does not fall out during assembly.

[0085] The base body 1 has in addition a gas passage opening 15 through which a pressure compensation between housing interior and the environment as well as in reverse can take place.

[0086] Furthermore, the battery 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 on the inner side 17 around the gas passage opening 15 of the base body 1 fluid-tightly to the base body 1, preferably welded or glued, namely to the rim 151 of the gas passage opening 15. The membrane 6 is present at the inner side 17 of the base body 1 and is at least partially engaged from behind by the second filter 2.

[0087] The gas passage opening 15 or the membrane 6 is covered furthermore by a fluid-permeable second filter 2 as a membrane support device 3 which is present at a second distance from the membrane 6. The second filter 2 has a plurality of grid stays 21 between which a plurality of grid openings 24 are present. The second filter 2 in the present embodiment is configured as a stamped sheet metal part.

[0088] At its outer side 18, a cover hood 5 is connected to the base body 1 and comprises at least one venting opening 51 and is configured to provide a 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 cover hood therefore contribute significantly to a high IP protection class.

[0089] The cover hood 5 can be fastened, for example, by means of a locking element engagement to the base body 1.

[0090] Furthermore, the battery degassing unit 10 comprises a first filter 8 comprising a plurality of openings 81. The first filter 8 is positioned at a first distance from the membrane 6 that is larger than the second distance at which the second filter 2 is positioned. In addition, the openings 81 of the first filter 8 are larger than the openings 24 of the second filter 2. By means of the first filter 8, particles released from individual or several battery cells in case of a cell defect can be retained in the housing interior.

[0091] The first grid openings 81 are provided for separating larger particles and the second grid openings 24 are provided for separating smaller particles that are smaller than the larger particles. The dimensions of the second grid openings 24 of the second filter 2 in at least one direction of extension can thus be advantageously smaller than the dimensions of the first grid openings 81 of the first filter 8. The second filter 2 provides an ingress protection so that long and pointed objects (for example, wires, screwdrivers or the like) cannot be inserted into the housing interior.

[0092] The dimensions of the grid openings 81 of the first filter 8 are advantageously to be selected such that a proportion as large as possible of a particle fraction can be retained thereby in order to prevent that they can reach the environment. The dimensions of the grid openings 81 of the first filter 8 are, for example, selected such that a certain mass proportion of the particles, for example, >75%, can be retained.

[0093] The corrugated shape of the first filter 8 enlarges the surface that is available for particle separation compared to a planar configuration and reduces therefore the tendency of the first filter 8 to block for gas flows that are heavily loaded with particles. An enlarged surface of the first filter 8 has furthermore the advantage that thermal peaks are distributed across a large surface which reduces the risk of thermally caused structural damages.

[0094] The first filter 8 is connected particle-tightly to the base body, according to the illustrated embodiment, in that it is clamped sandwich-like between the wall 4 of the battery housing and the base body 1. For facilitating mounting of the battery degassing unit 10, the first filter 8 can be at least prefixed additionally in relation to the base body 1; for this purpose, all connection types (for example, gluing) that appear suitable to a person of skill in the art are conceivable.

[0095] The base body 1 comprises moreover an emergency degassing spike 19. It extends toward the membrane 6 and is arranged in the rest state (no differential pressure load) at a certain distance from the outer membrane surface 61. Under pressure load (relative inner excess pressure), the membrane 6 will bulge in the direction toward the exterior space and, when 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 will rupture. This serves for ensuring an emergency degassing function that reacts as quickly as possible, which is important in order to be able to ensure that the housing structure remains intact in case of a sudden inner pressure increase in the battery housing. By a variation of the distance of the tip 191 of the emergency degassing spike 19 from the membrane surface 61, the emergency degassing pressure is adjustable.

[0096] At least one of the two filters 2, 8 (in the embodiments illustrated in the Figures, this is the first filter 8, respectively) can advantageously be corrugated such that a length extension 9 (see FIG. 2) in the stretched state in at least one direction is at least 1.3 times as large as in the corrugated state. Alternatively, the second filter 2 can be corrugated also.

[0097] The corrugated filter 8 is at least in sections thereof surrounded by side walls 22 which are formed at the second filter 2 as side walls 22 which are oriented toward the inner side 17 and project perpendicularly and which cover lateral openings 86 (see FIG. 4) of the corrugated filter 8, which are formed especially at the end face edges 85 of the folds 82, toward the battery housing.

[0098] In FIG. 3, an embodiment of the side walls 22 at the second filter 2 is illustrated in which the side walls 22 are of a continuous configuration, i.e., have no filter function, while in FIG. 4 an embodiment is illustrated in which the side walls 22 have openings 221 which enable at least passage of gas.

[0099] The corrugated filter 8 comprises folds 82 arranged in parallel to each other whose fold edges (i.e., fold tips and fold bases) are arranged parallel to the gas passage opening 15.

[0100] The first filter 8 is connected particle-tightly to the base body 1. In this context, a surface area which is spanned by the first filter 8 is larger than the cross section of the gas passage opening 15.

[0101] The dimensions of the grid openings 81 of the first filter 8 in at least one direction of extension can be smaller than 3.0 mm, preferably smaller than 2.0 mm, more strongly preferred smaller than 1.5 mm.

[0102] The first filter 8 can comprise, for example, a filter medium 83 that is preferably a grid material, in particular a wire mesh, and/or a nonwoven material. Preferably, the filter medium 83 in this context can comprise or can be comprised of a metallic material.

[0103] The first filter 8 can be connected together with the second filter 2 to the base body 1. For this purpose, the first filter 8 can comprise at least one fastening tab 87 with bores 871 which extends preferably laterally and which is suitable to connect the first filter 8 directly to the base body 1 by means of weld spots 12. In this manner, the first filter 8 can be connected by means of the fastening tabs 87, for example, by ultrasonic welding, friction stir welding or similar welding methods, to the fastening tabs 27 of the second filter 2. The fastening tabs 27, 87 comprise for this purpose bores 271, 871 through which, for example, weld spots 12 arranged in the base body 1 can be pushed through and connected to the fastening tabs 27, 87 of the two filters 2, 8, in particular welded.

[0104] Alternatively, it is also possible that the first filter 8 is snapped onto the second filter 2.

[0105] A distance between the first filter 8 and the second filter 2 in the region of the center of the gas passage opening 15 can amount beneficially to 0.2 mm, preferably at least 0.7 mm.

[0106] The first filter 8 can beneficially be embodied as a sheet metal part, in particular stamped sheet metal part. Alternatively, the first filter 8 can also be configured of a plastic material with a very high melting point.

[0107] In FIGS. 10 to 17, a further embodiment of a battery degassing unit 10 is illustrated. FIG. 10 shows an isometric section view of the battery degassing unit 10 while in FIG. 11 an isometric view, viewed from an inner side of the base body, is illustrated.

[0108] FIG. 12 shows a first filter 8 and a second filter 2 of the battery degassing unit 10 in isometric illustration.

[0109] FIG. 13 shows a plan view of the battery degassing unit 10 according to FIG. 10, viewed from an outer side 18 of the base body 1, with indicated section plane A-A and B-B, while in FIG. 14 a longitudinal section of the battery degassing unit 10 along the section plane A-A and in FIG. 15 an enlarged detail X of the longitudinal section is illustrated. FIG. 16 shows a longitudinal section of the battery degassing unit 10 along the section plane B-B and FIG. 17 a longitudinal section of the battery degassing unit 10 along the section plane C-C.

[0110] The principal configuration of the embodiment illustrated in FIGS. 10 to 17 of the battery degassing unit 10 corresponds largely to the embodiment illustrated in FIGS. 1 to 9. Therefore, only the difference between the two embodiments will be discussed for reasons of unnecessary repetitions.

[0111] The significant difference resides in that the side walls 84 of the corrugated filter 8 at least in sections are formed at the first filter 8 itself. Essentially, it can be seen in FIGS. 11 and 12 that the side walls 84 are formed of the filter medium 83 of the first filter 8 by suitable folding of the filter medium 83.

[0112] The side walls 84 are formed continuously, i.e., do not provide a filter function. Alternatively, it would also be possible to provide further openings in the side walls 84 so that here also at least a passage of gas would be possible.

[0113] The second filter 2 can therefore be configured flat (see FIG. 12). The first filter 8, as in the afore described embodiment, can be connected by means of fastening tabs 87 to the corresponding fastening tabs 27 of the second filter 2, for example, by ultrasonic welding, friction stir welding or similar welding methods. Alternatively, the two filters 2, 8 can also be connected by a snap-on connection.

[0114] In an alternative embodiment, not illustrated, of the battery degassing unit 10, the side walls 22, 84 at least in sections can be formed at the base body 1. In this case, the side walls 22, 84 can be formed as one piece together with the base body 1 and, for example, can be directly integrally formed thereat by an injection molding process.

[0115] In FIG. 18, a first filter 8 for a battery degassing unit according to the present invention is shown that is compatible with all herein described embodiments. The first filter 8 has multiple corrugations and comprises folds 82. The grid openings 81 are present herein also in the regions in which the cross section of the first filter 8 experiences an inversion of direction, i.e., in the region of the respective fold bases and/or fold tips of the folds 82. In addition, the fold surfaces that are not bent or curved are also provided with grid openings 81. This entails the technical advantage that these regions can be used additionally for filtration, which increases the effective separation surface.

REFERENCE CHARACTERS

[0116] 10 battery degassing unit [0117] 1 base body [0118] 11 fastening means region of action [0119] 12 weld spot [0120] 15 gas passage opening [0121] 151 rim of gas passage opening [0122] 16 seal receiving groove of the base body [0123] 17 inner side of the base body [0124] 18 outer side of the base body [0125] 19 emergency degassing spike [0126] 191 tip of the emergency degassing spike [0127] 2 second filter [0128] 21 grid stays [0129] 22 side wall [0130] 221 side wall opening [0131] 23 bore [0132] 24 grid openings [0133] 27 fastening tab [0134] 271 bore of the fastening tab [0135] 3 membrane support device [0136] 4 wall of the battery housing [0137] 5 cover hood [0138] 51 venting openings [0139] 6 semipermeable membrane [0140] 61 outer membrane surface [0141] 7 housing seal [0142] 8 first filter [0143] 81 grid openings [0144] 82 fold [0145] 83 filter medium [0146] 84 side wall [0147] 85 end face edge [0148] 86 opening [0149] 87 fastening tab [0150] 871 bore of the fastening tab [0151] 9 length extension