PRESSURE BALANCING DEVICE

Abstract

The present invention relates to a pressure balancing device for a battery case (1). The pressure balancing device comprises a base (3) and a vent valve (11) configured to move from a closed position to an open position to release excess pressure inside the battery case for emergency venting. The pressure balancing device also comprises a pressure balancing device (1) comprising a porous breathable membrane (9) which is gas permeable and liquid impermeable for pressure balancing between the inside of the device (1) and the outside of the device (1) when the vent valve (11) is in the closed position. The vent valve (11) and the breathable membrane are decoupled. Figure for abstract: Figure 4

Description

Title of the invention: PRESSURE BALANCING DEVICE Technical field of the invention

[0001] The invention relates to a pressure balancing device. The invention relates more particularly to a pressure balancing device for a battery box, in particular in a vehicle. Context

[0002] Pressure equalization devices are used to compensate for pressure variations within a battery case, releasing pressure in the event of overpressure.

[0003] Pressure balancing devices usually have a degassing function used in an emergency in case of overpressure, and a breathing function used permanently to balance the internal battery pressure with the local atmospheric pressure under normal operating conditions.

[0004] Patent document WO2023 / 218242A1 shows examples of a pressure balancing device where a degassing valve comprises a breathable membrane to provide both breathing and degassing functions. Summary of the invention

[0005] The objective of the invention is to provide an alternative solution to known pressure balancing devices.

[0006] For example, the invention relates to a pressure equalization device comprising a vent valve configured to release pressure from the interior of a battery case to the exterior of the battery case. The pressure equalization device may further comprise a gas-permeable and liquid-impermeable pressure-breathing membrane to equalize pressure between the interior of the device and the exterior of the device when the vent valve is closed.

[0007] According to a first aspect of the present invention, there is provided a pressure balancing device for a battery case, the pressure balancing device comprising a base, a vent valve configured to move from a closed position to an open position to release excess pressure within the battery case for emergency venting, and a porous breathable membrane that is gas permeable and liquid impermeable for pressure balancing between an interior of the device and an exterior of the device when the vent valve is in the closed position, wherein the vent valve and the breathable membrane are decoupled. In other words, the breathable membrane may be physically separate from the degassing valve. That is, they are mounted separately within the pressure balancing device.

[0008] Advantageously, decoupling the breathable membrane from the degassing valve simplifies manufacturing and avoids defects in one component creating operational problems in the other component.

[0009] In examples, the base includes a connector for connecting the base to the battery housing, particularly to an opening in the battery housing. The base may include a gasket for sealing the pressure equalization device against the battery housing. In various examples, the connector may include a clip, a threaded connector, or fasteners (including screws, circlips, and the like).

[0010] In examples, the base has a central cavity. The base and the central cavity may be cylindrical, with a longitudinal axis.

[0011] In examples, the breathable membrane is mounted on the base.

[0012] In examples, the breathable membrane is mounted within a cavity central cavity of said base. The base and the central cavity may be cylindrical, with a longitudinal axis, and the breathable membrane may extend perpendicular to the longitudinal axis. In examples, the base comprises at least one breathing conduit. In examples, the at least one breathing conduit is arranged to be in communication with the central cavity of the device when the degassing valve is in the closed position. The at least one breathing conduit may be arranged downstream of the breathable membrane and upstream of the degassing valve. In examples, the at least one breathing conduit is arranged to be in communication with the exterior of the device. In these examples, the base may be cylindrical and extend along a longitudinal axis and the one or more breathing conduits may extend substantially perpendicular to the longitudinal axis.

[0013] In other examples, the base includes at least one breathing conduit. The breathable membrane may be provided in or on the at least one breathing conduit. In examples, the at least one breathing conduit is arranged to be in communication with the central cavity of the device when the vent valve is in the closed position. The at least one breathing conduit may be arranged upstream of the vent valve. In examples, the at least one breathing conduit is arranged to be in communication with the exterior of the device. In examples, the pressure equalization device includes a plurality of breathing conduits and the membrane includes or is made of a plurality of porous breathable membrane bodies. In these examples, the base may be cylindrical and extend along a longitudinal axis and the one or more breathing conduits may extend substantially perpendicular to the longitudinal axis.The membrane(s). breathing may extend parallel to the longitudinal axis, through the breathing duct(s).

[0014] In examples, a first of the plurality of breathing ducts is radially opposed to a second of the plurality of breathing ducts relative to the longitudinal axis.

[0015] In this way, the breathable membrane(s) can balance the pressure when the degassing valve is in the closed position.

[0016] In examples, each of the breathable membrane bodies has the same characteristics as the membrane, for example being breathable and / or porous and / or gas permeable and liquid impermeable for pressure balance between an interior of the device and an exterior of the device when the degassing valve is in the closed position.

[0017] In examples, the breathable membrane is brazed or ultrasonically welded to the base, or secured by overmolding to the base.

[0018] In examples, the pressure balancing device further comprises a cover covering the base.

[0019] In examples, the cover includes a connector for connecting the cover to the base. In examples, the connector is an interior connector within the cover, for example, a male or female clip, or a thread, cooperating with a corresponding clip, latch, or thread located on the base.

[0020] In examples, the degassing valve may comprise an umbrella valve. The umbrella valve may comprise a central spigot or stem and an umbrella-shaped valve member extending therefrom. In examples, the degassing valve comprises an injected thermoplastic elastomer or is composed of a material comprising silicon.

[0021] In examples, the vent valve is mounted on the base. In particular, the vent valve may include a lug or stem that engages an opening in the base for mounting the vent valve. The opening in the base may be surrounded by one or more additional openings. The other openings may be covered by the vent valve in the closed position, and permit the passage of gas when the vent valve is open. The other openings may be arranged to communicate with the central cavity of the base. The opening may alternatively be shaped to permit the flow of gas through the opening when the lug or stem of the vent valve is received therein and the vent valve is in the open position. The base may define a valve seat, which may include a sealing member, against which the vent valve seals in the closed position.When the degassing valve opens, it . can move away from the valve seat, in particular by elastic deformation, allowing the gas to escape.

[0022] In other examples, the vent valve may be mounted on the lid. The lid and / or the vent valve may include a connector for connecting the vent valve to the lid. In particular, the vent valve may include a lug or stem that engages an opening formed in the lid. The base may define a valve seat, for example within a central cavity in the base. The valve seat may include a sealing member against which the vent valve seals when the lid (and vent valve) are secured to the base and the vent valve is in the closed position. One or more openings, preferably one opening, may be defined in the base to be closed by the vent valve. The one or more openings may be arranged to be in communication with the central cavity.When the degassing valve is opened, it may move away from the valve seat, in particular by elastic deformation, allowing the gas to escape through one or more openings.

[0023] Advantageously, this arrangement creates more space within the base of the pressure balancing device since the lug or rod is mounted on the cover. This can allow an increased degassing rate by releasing the volume below the degassing valve.

[0024] According to a second aspect of the present invention, a pressure equalization device is provided for a battery case, the pressure equalization device comprising a base connectable to the battery case, a cover connectable to the base, and a vent valve configured to move from a closed position to an open position to release excess pressure within the battery case for emergency venting, wherein the base comprises a valve seat and wherein the vent valve is mounted on the cover such that the vent valve engages the valve seat when the cover is secured to the base. The second aspect of the invention may be combined with all the features of the first aspect.

[0025] Optionally, the pressure balancing device further comprises a porous breathable membrane that is gas permeable and liquid impermeable for pressure balancing between an interior of the battery housing and the exterior of the battery housing when the vent valve is in the closed position.

[0026] Optionally, the degassing valve and the breathable membrane are decoupled as described above. In other words, the breathable membrane can be physically dissociated from the degassing valve.

[0027] In examples, the base may include one or more breathing conduits, as described above, and the one or more breathable membrane bodies may be mounted in or on the one or more breathing conduits.

[0028] In examples, the base includes a connector for connecting the base to the battery housing, particularly to an opening in the battery housing.

[0029] The base may include a seal. In various examples, the fitting may include a clip, a threaded fitting, or fasteners (including screws, circlips, and the like).

[0030] In examples, the breathable membrane is mounted on the base.

[0031] In examples, the breathable membrane is mounted within a cavity central part of said base. In examples, the base extends cylindrically.

[0032] In examples, the breathable membrane is substantially perpendicular to the longitudinal axis of the base.

[0033] In examples, the base comprises at least one breathing conduit and the breathable membrane is provided in or on the at least one breathing conduit.

[0034] In examples, the breathing conduit is arranged to be in communication with the interior of the device when the degassing valve is in the closed position. In this way, the breathing membrane can equalize the pressure when the degassing valve is in the closed position.

[0035] In examples, the pressure balancing device comprises a plurality of breathing conduits and the membrane comprises or is comprised of a plurality of breathable membrane bodies coupled within the plurality of breathing conduits.

[0036] In examples, the base extends along a longitudinal axis and the one or more breathing conduits extend substantially perpendicular to the longitudinal axis.

[0037] In examples, a first of the plurality of breathing ducts is radially opposed to a second of the plurality of breathing ducts relative to the longitudinal axis.

[0038] In examples, the breathable membrane is brazed or ultrasonically welded to the base, or secured by overmolding to the base.

[0039] In examples, the degassing valve comprises an injected thermoplastic elastomer or is composed of a material comprising silicon.

[0040] In examples, the cover includes a connector for connecting the cover to the base. In examples, the connector is an interior connector within the cover, for example, a male or female clip, or a thread, cooperating with a corresponding clip, latch, or thread located on the base.

[0041] In examples, the degassing valve may comprise an umbrella valve. The umbrella valve may comprise a central lug or stem and an umbrella-shaped sealing member extending therefrom.

[0042] In examples, the cover defines an interior chamber covering the base to protect it from the environment, including water.

[0043] The cover may be substantially cylindrical, with an open end that receives the base and faces toward the battery housing in use.

[0044] The sides and opposite end of the cover may be closed to provide protection.

[0045] A vent opening may be defined by the open end of the cover, facing the battery housing in use, through which the exterior of the pressure equalization device is in communication with the vent valve and the breathable membrane / breathable membrane bodies.

[0046] In examples, the base and / or the cover may comprise an injected thermoplastic elastomer.

[0047] The present invention also relates to the following aspects:

[0048] In examples, the degassing valve and the breathable membrane are decoupled.

[0049] In examples, the degassing valves and the breathable membrane are provided on different parts of the pressure balancing device.

[0050] In examples, the pressure balancing device comprises a base.

[0051] In examples, the breathable membrane facilitates pressure balance between the inside of the device and the outside of the device.

[0052] In examples, the breathable membrane is provided on the side of the pressure equalization device. In examples, the breathable membrane facilitates breathing from the sides of the pressure equalization device.

[0053] In examples, the breathable membrane is attached by overmolding onto the pressure balancing device.

[0054] In examples, the breathable membrane is secured by overmolding onto a base of the pressure balancing device.

[0055] In other examples, the breathable membrane is secured by ultrasonic welding to the pressure balancing device. In examples, the breathable membrane is secured by ultrasonic welding to a base of the pressure balancing device.

[0056] In examples, the breathable membrane is a porous membrane.

[0057] In examples, the breathable membrane is impermeable to liquids.

[0058] In examples, the gas permeable membrane is gas permeable.

[0059] In examples, the breathable membrane is formed from a material comprising polytetrafluoroethylene (PTFE).

[0060] In examples, the breathable membrane is formed from a material comprising expanded polytetrafluoroethylene (ePTFE).

[0061] In examples, the pressure balancing device comprises a housing.

[0062] In examples, the housing defines an interior chamber.

[0063] In examples, the degassing valve is located in the housing.

[0064] In examples, the degassing valve is configured to release pressure from the inside of the case to the outside of the case.

[0065] In examples, the housing and the base are provided at different portions of the balancing device.

[0066] In examples, the vent valve is configured to release excess pressure within the housing for emergency venting.

[0067] In examples, the degassing valve is an umbrella valve.

[0068] In examples, the degassing valve is composed of a material comprising a thermoplastic elastomer (TPE).

[0069] In examples, the degassing valve is made of a material comprising 1k thermoplastic elastomer (TPE).

[0070] In other examples, the degassing valve is composed of a material comprising silicon. Brief description of the drawings

[0071] The invention will be better understood by a detailed study of certain embodiments taken as non-limiting examples and illustrated by the appended drawings, in which:

[0072] [Fig.l] shows a first example of a pressure balancing device, with a perspective view from below.

[0073] [Fig.2] shows the pressure balancing device of [Fig.l] from below.

[0074] [Fig. 3] shows the pressure balancing device of [Fig. 1] in section. transverse from the bottom.

[0075] [Fig.4] shows the pressure balancing device of [Fig.l] in cross-section from the front.

[0076] [Fig.5] shows a second example of a pressure balancing device, with a perspective view from below.

[0077] [Fig.6] shows the pressure balancing device of [Fig.5] in cross-section from below.

[0078] [Fig.7] shows the pressure balancing device of [Fig.5] in cross-section from the front.

[0079] [Fig.8] shows the pressure balancing device of [Fig.5] in cross-section from the front. Detailed description

[0080] Figures 1 to 4 illustrate a first example of a pressure balancing device 1.

[0081] In view of the above, the pressure balancing device is suitable for a battery case, and comprises a base 3, a vent valve 11 configured to move from a closed position to an open position to release excess pressure inside the battery case for emergency venting, and a porous breathable membrane 9 which is gas permeable and liquid impermeable for pressure balancing between an interior of the device 1 and an exterior of the device 1 when the vent valve 11 is in the closed position.

[0082] The degassing valve 11 and the breathable membrane 9 are decoupled. In other words, the degassing valve 11 and the breathable membrane 9 are separated or physically dissociated.

[0083] The base 3 of the pressure balancing device 1 extends along a longitudinal axis X and defines a fluid passage between an inlet and an outlet of said base 3. The base 3 may be attached to a battery housing, and in particular to an opening of a battery housing such that the interior of the battery housing is in fluid communication with the pressure balancing device 1. The base 3 has a central cavity 20 which extends from an inlet (where the base attaches to the battery housing) to one or more outlets.

[0084] The pressure balancing device 1 comprises a degassing valve 11. The degassing valve 11 is mounted on the base 3 and is movable between a closed position and an open position. In this example, the degassing valve 11 is an umbrella valve. The degassing valve 11 comprises a cylindrical spigot or stem 19 and an umbrella valve member extending therefrom. The stem 19 is mounted on the base 3 such that the umbrella valve member covers a passage through the base 3.

[0085] The base 3, in particular the central cavity 20, delimits a central opening in which the lug 19 is mounted, and one or more degassing openings arranged around the central opening to be covered by the degassing valve 11 in the closed position.

[0086] In examples, the degassing valve is made of a material comprising 1k thermoplastic elastomer (TPE). TPE or eTPE valves have significant elastic memory and opening capacity in the event of degassing, without plastic deformation.

[0087] In its closed position, the umbrella valve member of the degassing valve 11 rests against a degassing valve seat of the base 3, for example against a sealing member 5 placed on this degassing valve seat. In this position, the degassing valve 11 ensures the sealing of the outlet. This is the normal operating state of the pressure balancing device 1.

[0088] The degassing valve 11, in particular the umbrella valve member, is configured to deform elastically for degassing. In particular, in the event of overpressure beyond a predetermined threshold within the battery housing, the pressure acting on the umbrella valve member causes it to deform and move away from the seat (sealing member 5), allowing degassing through the outlet.

[0089] Specifically, in the open position of the vent valve 11, the outlet is not sealed by the vent valve 11 and may create a vent flow 17 by allowing overpressure gas from the inlet flow to pass outside the pressure equalization device 1 through the outlet, thereby allowing venting of the inlet, i.e., the battery box of the vehicle. Such an overpressure condition may occur due to thermal runaway of the battery cells within the battery box.

[0090] The degassing valve 11 is used only for degassing, having only this function, and no breathing function.

[0091] The pressure balancing device 1 also comprises a porous breathable membrane 9. The breathable membrane 9 is mounted at the inlet of the base 3. Specifically, the base 3 extends cylindrically and the breathable membrane 9 is mounted inside the central cavity 20 within the base 3, at the inlet. In this way, all gas passing from the battery housing into the pressure balancing device 1 passes through the breathable membrane 9. The breathable membrane 9 is therefore arranged to extend perpendicular to the longitudinal axis X. That is, the inlet extends parallel to the longitudinal axis X and the breathable membrane 9 extends transversely to the inlet, perpendicular to the longitudinal axis X.

[0092] In some examples, the breathable membrane 9 is configured to rupture or break or dislodge upon overpressure, thereby reducing restriction of gas flow through the pressure equalization device 1. In some examples, the breathable membrane 9 is configured to melt or disintegrate at a predetermined temperature, for example a temperature corresponding to thermal runaway on one or more battery cells in the battery housing.

[0093] As illustrated, the pressure balancing device 1 comprises at least one breathing duct 15, in particular a plurality of breathing ducts 15. The breathing ducts 15 fluidly connect the interior of the battery case with the external ambient pressure and thus facilitate a breathing function of the pressure balancing device 1, even when the degassing valve 11 is in the closed position.

[0094] In this example, the breathing conduits 15 extend from a location within the base 3 between the degassing valve 11 and the breathing member 9 thereby allowing the flow of breathing gas when the degassing valve 11 is in the closed position. The breathing conduits 15 extend laterally (sideways) relative to the longitudinal axis X, on one side of the base.

[0095] As previously described, in the illustrated example, the breathing member 9 is mounted on the base 3 at the inlet. However, in other examples, for example as illustrated in Figures 5 to 8, the breathing member 9 may be mounted in or on the breathing conduits 15. If a plurality of breathing conduits 15 are provided, then a plurality of breathing membrane bodies 9 may be provided, one breathing membrane body 9 for each breathing conduit 15. In these examples, the one or more breathing membranes 9 may extend in a direction parallel to the longitudinal axis X, passing through the laterally extending breathing conduits 15. The or each of the breathing membranes 9 may close an outlet of the one or more breathing conduits 15.

[0096] The breathable membrane 9 is gas permeable and liquid impermeable. The breathable membrane 9 allows the passage of gas through the breathable membrane 9 in order to balance the pressure at the inlet, i.e. inside the battery case 1, with the ambient pressure outside the base 3. The breathable membrane 9 is always exposed to the internal pressure of the battery case and the ambient pressure, which ensures a breathing function illustrated by the breathing flow 16.

[0097] The breathing flow 16 is a low volume flow, present permanently during normal operation, between the inside and the outside of the battery case via the pressure balancing device 1. In this way, the breathing function does not affect the degassing function.

[0098] The breathable membrane 9 is, for example, a hydrophobic breathable membrane, which prevents the entry of liquids into the battery box. The breathable membrane 9 contains, for example, polytetrafluoroethylene (TPE) or expanded polytetrafluoroethylene (eTPE). The breathable membrane 9 therefore facilitates pressure balance between an interior of the device 1 and an exterior of the device 1 by the breathing flow 16.

[0099] As previously described, in the example of Figures 1 to 4, the degassing valve 11 is mounted on the base 3. A cover 7 is mounted on the base 3 and covers the degassing valve 11. The cover 3 may be secured to the base 3 by a thread or a clip or the like. The cover 3 and the base 3 are not fluid-tight and openings are defined. The cover 7 has a generally cylindrical shape, with an open side which faces the battery box when attached to the base 3. The open side of the cover 7, optionally with cutouts in the side wall of the cover 7, creates openings through which gas can pass to / from the breathable membrane 9 and the degassing valve 11 for breathing and degassing, respectively.

[0100] In the example of Figures 5 to 8, the degassing valve 11 is mounted on the cover 7. In particular, the degassing valve 11 has an opening and the cover 7 comprises a connection in the form of a lug 21 for mounting the degassing valve 11 on the cover 7. In other examples, the degassing valve 11 may be connected to the cover 7 by clips or by welding or by another type of fixing.

[0101] The body 3 has a central cavity 20 and a sealing surface (with gasket 5), and the degassing valve 11 seals against the sealing surface when the cover 7 is attached to the base 3, as shown in [Fig.7].

[0102] Preferably, the degassing valve 11 comprises an injected thermoplastic elastomer or is composed of a material comprising silicon. In other examples, the degassing valve 11 is composed of a material comprising silicon.

[0103] In this example, the breathing ducts 15 extend laterally from the central cavity in the same manner as previously described with reference to the example of FIGS. 1 to 4. In this example, the pressure balance 1 comprises breathable membrane bodies 9 provided in or on each of the breathing ducts 15, in particular at the outlets of the breathing ducts 15. Alternatively, as in the example of FIGS. 1 to 4, the breathable membrane 9 may be provided in the central cavity 20, at the inlet.

[0104] In the example of Figures 5 to 8, the central cavity 20 extends parallel to the longitudinal axis X. The breathing ducts 15 extend laterally to a lateral surface of the body 3. Specifically, the base 3 is generally cylindrical and the breathing ducts 15 extend perpendicular to the longitudinal axis X to a surface of the body 3. As illustrated, a first of the breathing ducts 15 may be radially opposite a second of the breathing ducts 15 with respect to the longitudinal axis X.

[0105] The cover 7 may be secured to the base 3, for example the cover 7 is screwed or clipped onto the base 3. The cover 7 has a generally cylindrical shape with an open side that faces the battery case in use. Openings are provided in the open side of the cover (and / or in a side wall of the cover 7) for the passage of gas during breathing and degassing. Specifically, when the cover 7 is secured to the base 3, it is spaced from the ends of the breathing conduits 15 and a fluid path is defined from the vent valve to the outside, as shown as vent flow 17 in [Fig.8].

[0106] In this example, the breathable membrane 9 (or membrane body 9) is disposed on or in the breathing ducts and extends substantially perpendicular to the longitudinal axis X. As illustrated, the breathable membrane 9 (or membrane body 9) is mounted at the ends of the breathing duct(s) 15. The breathable membrane 9 (or membrane body 9) covers the breathing duct(s) 15. The breathable membrane 9 (or membrane body 9) are attached to the base 3 to close the outlets of the breathing duct(s) 15. The breathable membrane 9 (or membrane body 9) may be ultrasonically welded or brazed to the base 3. Alternatively, the breathable membrane 9 may be overmolded or co-molded with the base 3.

[0107] As illustrated, two breathing conduits 15 are radially opposite with respect to the longitudinal axis X and each comprise a breathable membrane body 9. Other breathing conduits 15 may be provided, for example three, four, five or more breathing conduits 15.

[0108] [Fig.7] illustrates the pressure balancing device 1 in its closed position, in which the degassing valve 11 is not engaged with the degassing function, the pressure threshold not being reached on the inlet side of the degassing valve 11.

[0109] [Fig.8] illustrates the pressure balancing device 1 in its open (venting) position, in which the internal pressure of the battery housing has deformed the vent valve 11 so that the umbrella valve member has moved away from the seat, allowing a passage for the vent flow 17.

[0110] The example of Figures 5 to 8 advantageously increases the volume of the central cavity 20 within the base 3 because the degassing valve stem 19 is located within the cover 7. Higher degassing flow rates are thus obtained because the opening covered by the degassing valve 11 is larger, allowing a greater opening when the degassing valve 11 is deformed.

[0111] In summary, the pressure balancing device 1 comprises a degassing valve 11 which releases pressure in the event of overpressure (emergency degassing), and comprises a breathable membrane 9 which is separate from the degassing valve 11 and facilitates pressure balancing between an interior of the device 1 and an exterior of the device 1.

[0112] Thus, the emergency degassing and pressure balancing functions are performed by (i.e. at) separate parts of the pressure balancing device which are decoupled from each other. List of reference signs

[0113] 1 pressure balancing device

[0114]

[0115]

[0116]

[0117]

[0118]

[0119]

[0120]

[0121]

[0122]

[0123]

[0124]

[0125] 3 base 5 sealing member 7 cover 9 breathable membrane 11 degassing valve 15 breathing ducts 16 breathing outlet 17 degassing outlet 19 degassing valve stem 20 central cavity 21 connection X longitudinal axis

Claims

Claims

1. A pressure balancing device for a battery case (1) the pressure balancing device comprising a base (3), a vent valve (11) configured to move from a closed position to an open position to release excess pressure inside the battery case for emergency venting, and a porous breathable membrane (9) which is gas permeable and liquid impermeable for pressure balancing between the inside of the pressure balancing device (1) and the outside of the pressure balancing device (1) when the vent valve (11) is in the closed position, wherein the vent valve (11) and the breathable membrane (9) are decoupled.

2. A pressure balancing device (1) according to claim 1, wherein the breathable membrane (9) is mounted on the base (3).

3. A pressure balancing device (1) according to claim 2, wherein the breathable membrane (9) is mounted inside a central cavity (20) of said base (3).

4. A pressure balancing device (1) according to any one of claims 1 to 3, wherein the base (3) comprises at least one breathing duct (15) and wherein the breathable membrane is provided in or on the at least one breathing duct (15), and wherein the at least one breathing duct (15) is arranged to be in communication with a central cavity of the pressure balancing device (1) when the degassing valve (11) is in the closed position.

5. A pressure balancing device (1) according to claim 4, comprising a plurality of breathing conduits (15), the membrane comprising or consisting of a plurality of breathing membrane bodies (9).

6. A pressure balancing device (1) according to claim 5, wherein the base (3) extends along a longitudinal axis (X) and the breathing ducts (15) extend substantially perpendicular to the longitudinal axis (X).

7. A pressure balancing device (1) according to claim 6, wherein a first of the plurality of breathing conduits (15) is radially opposite a second of the plurality of breathing ducts (15) relative to the longitudinal axis (X).

8. A pressure balancing device (1) according to any one of claims 1 to 7, wherein the breathable membrane (9) is ultrasonically welded or brazed to the base (3), or fixed by overmolding to the base (3).

9. A pressure balancing device (1) according to any one of claims 1 to 8, wherein the degassing valve (11) comprises an injected thermoplastic elastomer or is made of a material comprising silicon.

10. A pressure balancing device (1) according to any one of claims 1 to 9, further comprising a cover (7) covering the base (3).

11. A pressure balancing device (1) according to claim 10, wherein the degassing valve (11) is mounted on the cover (7).

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