Emergency degassing unit for degassing a battery housing and battery housing

Abstract

This invention relates to an emergency degassing unit (100) for degassing a battery casing, particularly a traction battery casing of a motor vehicle, comprising: a base (10) having a valve unit (30), wherein the valve unit (30) includes a flexible valve retainer (32) and a sealing element (34), the valve retainer (32) being eccentrically fixed to the base (10), wherein the valve retainer (32) is mounted to the base (10) using a mechanical preload force in the axial direction (16). If the force acting on the sealing element (34) due to pressure in the battery casing is less than the preload force of the valve retainer (32), the sealing element (34) is in a closed position, and if the force acting on the sealing element (34) due to pressure in the battery casing exceeds the preload force of the valve retainer (32), the sealing element (34) is in an open position. The invention also relates to a battery casing.

Description

Technical Field

[0001] The present invention relates to an emergency degassing unit for degassing a battery casing, particularly a traction battery casing of a motor vehicle, and a battery casing, particularly a traction battery casing of a motor vehicle. Background Technology

[0002] A battery storage system used as a stationary system or vehicle traction battery contains a number of battery cells.

[0003] In the event of a battery system failure, hot gases and particles may escape from the battery cells. A ventilation unit with a semi-permeable membrane is typically used; when the gas pressure inside the battery casing exceeds a certain limit, an emergency degassing function is triggered by puncture of a pointed tip. Therefore, after this event, the membrane ceases to function. This is typically used for thermal degassing when temperatures exceed 300°C and the battery cells begin to experience thermal runaway.

[0004] Resealable ventilation units are also known in the art.

[0005] For example, DE102021123420A1 describes an emergency venting valve comprising a base for connection to a venting opening in a room to be vented, wherein the base has an emergency venting opening. Furthermore, a pressure cap is provided to close the emergency venting opening. The emergency venting valve is characterized in that a spring device applies a predetermined force to the pressure cap, holding the pressure cap in a closed position, wherein the spring device is designed to release the pressure cap when a predetermined internal pressure is reached in the space to be vented, such that the emergency venting opening remains open even if the pressure in the space to be vented again falls below the predetermined internal pressure.

[0006] Furthermore, US2022 / 0363210A1 describes a protective device for a housing (such as a battery housing) for venting overpressure from the interior of the housing. The protective device has a sealing element for sealing an opening in the housing in a first operating state. The sealing element is arranged to be movable relative to the housing and configured to move non-destructively to a second operating state. A bearing element is provided for guiding the sealing element. The sealing element may have a membrane with predetermined permeability in at least certain areas, and in the second operating state, the sealing element opens the opening in the housing. Summary of the Invention

[0007] The purpose of this invention is to provide an improved emergency degassing unit for degassing battery casings, particularly traction batteries of motor vehicles.

[0008] Another objective is to provide a battery housing, particularly a battery housing for a traction battery of a motor vehicle, which has an improved emergency degassing unit.

[0009] According to one aspect of the invention, this objective is achieved by an emergency degassing unit for degassing a battery housing, particularly a traction battery of a motor vehicle, the emergency degassing unit comprising a base having a front side and an opposing rear side in an axial direction, having a circumferentially extending edge surrounding a degassing channel and having a valve unit, the base being configured to be mounted together with the rear side to a degassing opening in the battery housing, wherein the valve unit comprises a flexible valve retainer and a closing element, the valve retainer being eccentrically fixed to the base and surrounding the closing element in a closed position, wherein the valve retainer is mounted to the base using a mechanical preload force in an axial direction, wherein the closing element is in a closed position if the force acting on the closing element due to pressure in the battery housing is less than the preload force of the valve retainer, and the closing element is in an open position if the force acting on the closing element due to pressure in the battery housing exceeds the preload force of the valve retainer, wherein a protective cover is arranged above the closing element in an axial direction to restrict movement of the valve retainer in the axial direction 16 when the closing element is in the open position.

[0010] According to another aspect of the invention, another object is achieved by a battery housing, particularly a battery housing for a traction battery of a motor vehicle, the battery housing having an emergency degassing unit and having at least one degassing opening, wherein the emergency degassing unit is installed at at least one degassing opening and configured to open the passage when a defined pressure in the battery housing exceeds a threshold, and to close the passage when the pressure is below the threshold.

[0011] Advantageous embodiments are described in the dependent claims, the specification and the drawings.

[0012] An emergency degassing unit for degassing a battery casing, particularly a traction battery casing of a motor vehicle, is proposed. The unit includes a base having a front side and an opposing rear side in an axial direction, a circumferentially extending edge surrounding a degassing channel, and a valve unit. The base is configured to be mounted together with the rear side to a degassing opening in the battery casing. The valve unit includes a flexible valve retainer and a closing element. The valve retainer is eccentrically fixed to the base and surrounds the closing element in its closed position. The valve retainer is mounted to the base using a mechanical preload force in the axial direction. If the force acting on the closing element due to pressure in the battery casing is less than the preload force of the valve retainer, the closing element is in the closed position; and if the force acting on the closing element due to pressure in the battery casing exceeds the preload force of the valve retainer, the closing element is in the open position. A protective cover is arranged axially above the closing element to restrict axial movement of the valve retainer when the closing element is in the open position.

[0013] The proposed emergency degassing unit includes a resealable low-pressure valve unit mounted to the base. A protective cover is fixed to the base and has two main functions. The first function is to support and restrict valve movement. The maximum elongation of the open valve is determined by the distance between the protective cover and the valve itself. The second function is to protect the valve from external high-pressure water jet cleaning or any harmful objects.

[0014] The degassing unit can be secured to the battery wall using threaded inserts, bayonet mounts, or snap-fit ​​fittings, and can be sealed using gaskets or O-rings of any shape.

[0015] The valve unit includes a flat sheet metal valve retainer, such as from stainless steel with a thickness of 0.5 mm, having a specific geometry that provides flexibility for low opening pressures. The valve retainer can be secured to the base via two plastic pins. The valve unit also includes a silicone elastomer-coated molded part (e.g., vinyl methyl quartz (VMQ)) as a sealing element attached to the valve retainer and ensuring proper tightness with the valve seat on the base. This tightness is achieved by the preload force of the valve retainer. The valve may have a pretension of the flat sheet metal valve retainer at the end of a folded edge to constantly press the sealing element against the valve seat.

[0016] This resealable valve serves two main functions: first, to release dangerous gas overpressure from the battery casing in a short time; and second, to protect the battery system from water ingress.

[0017] The opening pressure is maintained by the valve's design itself, as the flat sheet metal of the valve retainer is cut into a specific shape that is indeed flexible enough to open under low overpressure inside the battery casing. Gas overpressure pushes from the inside against the free surface of the elastomer-coated molded part. The force generated by the pressure is then transmitted through the flexible arm of the valve retainer to a fixed point at the base, instantly opening the valve by moving the closure element toward the protective cap. If the overpressure is released, the closure element is released, and the valve closes again.

[0018] The necessary force generated by the pre-deformation of the metal sheet of the valve retainer enables the deformation of the elastomer-coated molded part to achieve waterproofing and leak prevention.

[0019] Advantageously, the solution of the present invention allows for low-pressure valves, where the restrictions required for opening pressure are significantly reduced. A resealable valve may begin to open at an overpressure of approximately 20 mbar. If the gas overpressure is released from the outset, the internal components of the battery housing will no longer be subjected to gas load, and faulty units can be easily detected.

[0020] Emergency degassing units can also exhibit low production costs.

[0021] According to an advantageous embodiment of the emergency degassing unit, the valve retainer may include an annular element integral with the valve retainer, and is molded as a sealing element by overmolding with an elastomer, particularly a silicone elastomer (especially vinyl methyl quartz). Therefore, a reliable connection between the valve retainer and the sealing element can be achieved.

[0022] According to an advantageous embodiment of the emergency degassing unit, the annular element may be configured with one or more links for interlocking between the valve retainer and the silicone elastomer-coated molding. The unique connection between the sheet metal valve retainer and the elastomer-coated molding can be achieved by using specific links, thus not being limited to adhesion between the metal and the elastomer.

[0023] According to an advantageous embodiment of the emergency degassing unit, the sealing element can be configured with a concave shape when viewed from the cover. Therefore, the shape of the sealing element can be maintained even when there is high pressure from the inside of the battery casing.

[0024] According to an advantageous embodiment of the emergency degassing unit, the valve retainer can be a flat sheet of metal, particularly stainless steel. Advantageously, the required flexibility of the valve retainer can be achieved.

[0025] According to an advantageous embodiment of the emergency degassing unit, the valve retainer can be secured to the base by at least two pins, particularly plastic pins, integrally formed with the base. The valve retainer can be reliably secured to the base by welding two plastic pins to it.

[0026] According to an advantageous embodiment of the emergency degassing unit, the valve retainer can be configured with a pre-deformed folded edge. Advantageously, this allows for a tight seal between the resealed valve and the inlet opening.

[0027] According to an advantageous embodiment, the emergency degassing unit may include mounting elements and sealing elements for mounting together with the rear side of the battery housing to the degassing opening in a substantially fluid-impermeable manner. This ensures that the emergency degassing unit is easily and securely secured to the battery housing.

[0028] According to an advantageous embodiment of the emergency defrosting unit, the mounting elements of the base may include one of a threaded insert, a bayonet, or a snap-fit ​​fitting to secure it to the wall of the battery housing. This ensures that the emergency defrosting unit is easily and securely fixed to the battery housing.

[0029] According to an advantageous embodiment of the emergency degassing unit, the sealing element can be a shaped gasket or an O-ring. The substrate can be reliably sealed to the battery housing.

[0030] Furthermore, a battery housing, particularly a traction battery housing for a motor vehicle, is proposed, having an emergency degassing unit and at least one degassing opening, wherein the emergency degassing unit is installed at at least one degassing opening and configured to open the passage when a defined pressure in the battery housing exceeds a threshold, and to close the passage when the pressure is below the threshold.

[0031] Even for low overpressure values, reliable degassing of overpressure inside the battery casing can be achieved through the emergency degassing unit. If the gas causing the overpressure is expelled and normal pressure is re-established inside the battery casing, the reclosable valve of the emergency degassing unit will close again to allow the battery to continue operating. Attached Figure Description

[0032] The invention and the above and other objects and advantages are best understood from the following detailed description of the embodiments, which are not limited to the embodiments shown: Figure 1 An emergency degassing unit for degassing a battery casing, particularly a traction battery casing of a motor vehicle, is shown from the front in an isometric view according to an embodiment of the present invention. Figure 2 According to the rear side Figure 1 Emergency degassing unit; Figure 3 Showing according to Figure 1 Exploded view of the emergency degassing unit; Figure 4 An inside view of the emergency degassing unit in the closed position of the sealing element is shown; Figure 5 A cross-sectional view of the emergency degassing unit in the closed position of the sealing element is shown; Figure 6 An internal view of the emergency degassing unit in the open position of the closed element is shown; and Figure 7 A cross-sectional view of the emergency degassing unit in the open position of the closed element is shown. Detailed Implementation

[0033] In the accompanying drawings, the same elements are denoted by the same reference numerals. The drawings are merely schematic and are not intended to depict specific parameters of the invention. Furthermore, the drawings are intended to depict typical embodiments of the invention only and should therefore not be considered as limiting the scope of the invention.

[0034] Figure 1 An emergency degassing unit 100 for degassing a battery casing, particularly a traction battery of a motor vehicle, according to an embodiment of the present invention, is depicted from the front side 12 in an isometric view. Figure 2 The emergency degassing unit 100 is depicted from the rear side 14, while Figure 3An exploded view of the emergency degassing unit 100 is shown in the figure.

[0035] The emergency degassing unit 100 includes a base 10 having a front side 12 and an opposing rear side 14 in an axial direction 16. The base 10 has a circumferentially extending edge 24 surrounding a degassing passage 22. The base also includes a valve unit 30.

[0036] The substrate 10 and the protective cover 26 can be made of, for example, polypropylene (PP) reinforced with glass fiber (GF 30).

[0037] The valve unit 30 includes a flexible valve retainer 32 and a closing element 34. The valve retainer 32 is eccentrically fixed to the base 10 to ensure its flexibility and surrounds the closing element 34 in the closed position.

[0038] The valve retainer 32 is mounted to the base 10 using a mechanical preload force in the axial direction 16.

[0039] If the force exerted on the closing element 34 by the pressure in the battery housing is less than the preload force of the valve retainer 32, the function of the valve unit 30 is defined by the closing element 34 in the closed position; and if the force exerted on the closing element 34 by the pressure in the battery housing exceeds the preload force of the valve retainer 32, the function of the valve unit 30 is defined by the closing element 34 in the open position.

[0040] In addition, the protective cover 26 is arranged above the closing element 34 in the axial direction to limit the movement of the valve retainer 32 in the axial direction 16 when the closing element 34 is in the open position.

[0041] The substrate 10 is configured to be mounted together with the rear side 14 to the degassing opening of the battery housing.

[0042] The valve retainer 32 includes an annular element 36. The annular element 36 is integral with the valve retainer 32 and is molded with an elastomer-coated molding part 40, particularly with a silicone elastomer-coated molding part (especially vinyl methyl quartz), as a closing element 34.

[0043] Valve retainer 32 can advantageously be a flat sheet of metal, particularly stainless steel, for example, with a thickness of 0.5 mm.

[0044] The preload force can advantageously be, for example, 50 N, generating a compressive force of 2 N on the valve seat on the elastomer-coated molding 40. With a maximum valve stroke of 10 mm for opening the closing element 34 in the axial direction 16, an opening pressure as low as, for example, 50 mbar at room temperature may be sufficient to open the valve unit 30.

[0045] Suitable manufacturing process techniques for valve retainer 32 may include cutting, for example by laser, water ray sampling and stamping for mass production, followed by overmolding with silicone elastomer to form the specific shape of closed element 34.

[0046] The valve retainer 32 is secured to the base 10 by at least two pins 42, particularly plastic pins, which are integral with the base 10.

[0047] The base 10 includes a mounting element 18 and a sealing element 20 for mounting together with the rear side 14 to a venting opening in the battery housing in a substantially fluid-impermeable manner. As shown, the mounting element 18 may include a threaded insert 44 or a bayonet or snap-fit ​​engagement for securing to the wall of the battery housing. The sealing element 20 may be a gasket 46 or an O-ring as shown.

[0048] exist Figure 1 In the middle, the emergency degassing unit 100 is shown from the front side 12, and the protective cover can be seen to be mounted to the base 10 by four mounting elements 28 (e.g., bolts). The channel 22 is the gap around the protective cover 26 between the cover 26 and the base 10.

[0049] exist Figure 2 In the middle, the emergency degassing unit 100 is shown from the rear side 14, where four mounting elements 18 implemented as threaded inserts 44 and a surrounding sealing element 20 implemented as a shaped gasket can be seen. A channel 22 passes through the inlet opening 11.

[0050] exist Figure 3 The geometry of the valve retainer 32 can be seen in the image. The valve retainer 32 surrounds the closing element 34 and terminates in the fixing element 50, which is used to mount the valve retainer 32 to the base 10 by means of two plastic pins 42.

[0051] Figure 4 An internal view of the emergency degassing unit 100 in its closed position with the sealing element 34 is depicted. The valve retainer 32 is mounted to the base 10 via the fixing element 50 using two plastic pins 42. On the other hand, a portion of the fixing element 50 is to be inserted into the base 10 for mounting the valve unit 30 with a preload force so that the inlet opening 11 is sealed by the sealing element 34 when normal pressure is present in the battery housing.

[0052] The closure element 34 is connected to the valve retainer 32 via the interconnecting element 52, which serves as a connector between the annular element 36 of the closure element 34 and the surrounding valve retainer 32.

[0053] Figure 5 A cross-sectional view of the emergency degassing unit 100 in the closed position of the closing element 34 is depicted.

[0054] As can be seen in the cross-sectional view, the annular element 36 is configured with one or more links 38 for interlocking between the valve retainer 34 and the silicone elastomer-coated molding 40. Viewed from the cover 26, the closing element 34 is configured with a concave shape to withstand higher gas pressures from the inlet opening 11.

[0055] When the valve unit 30 is closed, it protects the inside of the battery housing from the possible water pressure 60 (as depicted by the arrow) that could allow water to enter from the outside.

[0056] The valve retainer 32 is configured with a pre-deformed folded edge 48 to maintain the tightness of the elastomer-covered molded part 40. The pre-deformation overlap 54 of the folded edge 48 can be, for example, 1 mm.

[0057] exist Figure 6 The image depicts an inner view of the emergency degassing unit 100 in the open position of the closing element 34.

[0058] The sealing element 34 is raised so that one side is connected to the valve retainer 32 via the interconnecting element 52. The sealing element 34 remains flat. The valve retainer 32 is deformed so that it is eccentrically mounted to the base 10 at two plastic pins 42. Thus, the channel 22 opens from the rear side 14 for degassing the battery housing in which the base 10 is mounted.

[0059] Figure 7 A cross-sectional view of the emergency degassing unit 100 in the open position of the closing element 34 is depicted.

[0060] An overpressure 62 of gas from the inside of the battery housing, depicted by an arrow, causes the sealing element 34 to press against the protective cover 26, which restricts the movement of the sealing element 34 in the axial direction 16, acting as the stroke of the valve unit 30. Therefore, when the defined pressure in the battery housing exceeds a threshold, the channel 22 from the inlet opening 11 through the inside of the base 10 to the outlet opening 13 opens, and when the pressure falls below the threshold, the channel 22 closes.

[0061] Figure Labels 10 Matrix 11. Entrance opening 12 Front 13. Exit opening 14 Rear side 16 Axial direction 18 Mounting Components 20 Sealing elements 22 channels 24 Edges 26 Protective Cover 28 Mounting Components 30 valve units 32 Valve retainer 34 Enclosed Components 36 Ring elements 38-link 40 Silicon elastomer coated molding parts 42 Plastic pins 44 Threaded insert 46 Shaped gaskets 48 Pre-deformed folded edges 50 Valve retainer fixing element 52 Interconnection elements 54 Pre-deformation overlap 60 water pressure 62 Gas overpressure 100 Emergency Degassing Unit

Claims

1. An emergency degassing unit (100) for degassing a battery casing, particularly a traction battery casing of a motor vehicle, comprising: A substrate (10) having a front side (12) along an axial direction (16) and an opposite rear side (14), having a circumferentially extending edge (24) surrounding a channel (22) for degassing and having a valve unit (30), the substrate (10) being configured to be mounted together with the rear side (14) to a degassing opening of the battery housing. in, The valve unit (30) includes a flexible valve retainer (32) and a closure element (34), the valve retainer (32) being eccentrically fixed to the base (10) and surrounding the closure element (34) in the closed position of the closure element (32). The valve retainer (32) is installed onto the base (10) using a mechanical preload force in the axial direction (16). Specifically, if the force exerted on the sealing element (34) by the pressure in the battery housing is lower than the preload force of the valve retainer (32), the sealing element (34) is in the closed position; and if the force exerted on the sealing element (34) by the pressure in the battery housing exceeds the preload force of the valve retainer (32), the sealing element (34) is in the open position. The protective cover (26) is arranged above the closure element (34) in the axial direction to restrict the movement of the valve retainer (32) in the axial direction (16) when the closure element (34) is in the open position.

2. The emergency degassing unit according to claim 1, wherein, The valve retainer (32) includes an annular element (36) integral with the valve retainer (32) and is overmolded with an elastomer-coated molding part (40), particularly with a silicone elastomer-coated molding part, particularly vinyl methyl quartz, as the closing element (34).

3. The emergency degassing unit according to claim 2, wherein, The annular element (36) is provided with one or more links (38) for interlocking between the valve retainer (34) and the silicone elastomer-coated molding (40).

4. The emergency degassing unit according to claim 1, wherein, Viewed from the cover (26), the closure element (34) is configured with a concave shape.

5. The emergency degassing unit according to claim 1, wherein, The valve retainer (32) is a flat sheet of metal, particularly stainless steel.

6. The emergency degassing unit according to claim 1, wherein, The valve retainer (32) is secured to the base (10) by at least two pins (42), particularly plastic pins, that are integral with the base (10).

7. The emergency degassing unit according to claim 1, wherein, The valve retainer (32) is configured with a pre-deformed folded edge (48).

8. The emergency degassing unit according to claim 1, comprising a mounting element (18) and a sealing element (20) for mounting together with the rear side (14) to the degassing opening of the battery housing in a substantially fluid-impermeable manner.

9. The emergency degassing unit according to claim 8, wherein, The mounting element (18) of the base (10) includes one of a threaded insert (44), a bayonet, and a snap-fit, for fixing to the wall of the battery housing.

10. The emergency degassing unit according to claim 8 or 9, wherein, The sealing element (20) is a shaped gasket (46) or an O-ring.

11. A battery housing, particularly a traction battery housing for a motor vehicle, comprising an emergency degassing unit (100) according to claim 1 and having at least one degassing opening. in, The emergency degassing unit (100) is installed at the at least one degassing opening and is configured to open the channel (22) when a defined pressure in the battery housing exceeds a threshold and to close the channel (22) when the pressure is below the threshold.

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