CN117594947A

CN117594947A - Pressure equalization element for a battery housing

Info

Publication number: CN117594947A
Application number: CN202311018050.8A
Authority: CN
Inventors: 安德里亚斯·格内修斯; 帕斯卡尔·冯多布策温斯基
Original assignee: Kako Co ltd
Current assignee: Kako Co ltd
Priority date: 2022-08-15
Filing date: 2023-08-14
Publication date: 2024-02-23
Also published as: DE102022003022A1

Abstract

The pressure equalization element for a battery housing has a housing with at least one inlet for a gas, preferably air. In addition, it has at least one air-permeable membrane which is firmly connected to at least one control element. When a predetermined pressure difference is exceeded, the control element can be moved from the first position into the second position and bring the diaphragm in motion. At least one breaking element is present in the path of movement of the membrane, which breaking element at least partially breaks the membrane when said membrane is displaced.

Description

Pressure equalization element for a battery housing

Technical Field

The invention relates to a pressure equalization element for a battery housing according to the preamble of claim 1.

Background

Such a pressure equalization element serves to equalize the pressure difference between the interior of the battery housing and the environment. For this purpose, a gas-permeable membrane is arranged in the housing of the pressure equalization element, which membrane enables a gas exchange between the interior of the battery housing and the environment. Thus, it is normally prevented that excessive pressure is generated in the battery case, which may cause damage to the battery. If an impermissible pressure builds up in the battery housing, for example in the case of overheating, the membrane is then plastically deformed, so that the gas no longer flows through the membrane, but rather the gas can flow directly from the gas inlet to the gas outlet, thus ensuring a rapid pressure drop. The membrane is destroyed when an impermissible pressure occurs. The problem in this prior art is that it is not ensured that the membrane is definitely destroyed under a defined pressure, and that it is then not possible to ascertain whether an inadmissibly high pressure has been generated in the battery housing and whether the membrane has been defined to be destroyed.

Disclosure of Invention

The object of the invention is therefore to configure a pressure equalization element of this type to ensure that the diaphragm is definitely destroyed.

According to the invention, this object is achieved in a pressure equalization element of this type by the characterizing features of claim 1.

The diaphragm of the pressure equalization element according to the invention is connected to the at least one control element. Thus, the control element moves with the diaphragm. In the first position of the control element, the diaphragm is in its initial position, in which it enables a continuous gas exchange between the interior of the battery housing and the environment. If the pressure difference between the ambient pressure and the pressure in the battery housing exceeds a predetermined limit value, the control element and the diaphragm are moved into a second position in which the pressure in the battery housing can drop rapidly. In this case, the membrane is at least partially destroyed by the destruction element, so that the high pressure in the battery housing can be rapidly reduced. Since the membrane is firmly connected to the control element, the membrane is reliably entrained and at least partially destroyed.

The control element is advantageously fastened centrally on the upper or lower side of the membrane. The membrane can thus be moved from the first position into the second position, so that it can be reliably destroyed in any case. Since the membrane advantageously has a circular contour, the control element can be fastened easily and reliably in the center of the membrane.

Advantageously, the breaking element is part of a force-transmitting element which acts on the control element in the first position. The force-transmitting element can thus hold the control element and thus also the diaphragm reliably in this first position. The breaking element provided on the force-transmitting member ensures that the diaphragm is broken in the deflected second position, so that a rapid pressure equalization between the interior of the battery housing and the environment is possible.

Advantageously, the control element is loaded by the force-transmitting member in the second position. The force-transmitting member then ensures reliably that the control element remains in this second position. It can then be reliably ascertained that the control element has moved, which is caused by an excessive pressure in the battery housing.

The destruction element can also be an integral part of the control element, so that a very simple construction of the pressure equalization element is obtained. The destruction element also ensures in this case that the membrane is at least partially destroyed in the deflected position or in the second position of the control element.

The breaking element may also be an integral part of the force-transmitting member.

Advantageously, the control element has two inclined surfaces, which are opposite to one another and preferably consist of conical surfaces. The force-transmitting element advantageously rests with spring sections against these inclined surfaces under the action of spring force in two positions of the control element. In this way the control element is positioned and held in two positions by the force-transmitting member.

If the force-transmitting element is embodied in a substantially U-shape, the legs forming spring sections which interact with the control element, a structurally simple design results.

The spring section of the force-transmitting element is advantageously provided with an abutment section (Anlegebaischnitt) which, under elastic prestress, abuts against the inclined surface of the control element at least in the first position of the control element. In the first position of the control element, the diaphragm is in its initial position, so that this initial position of the diaphragm can be reliably adjusted and maintained by means of the spring section of the force-transmitting element.

Advantageously, the force-transmitting element applies pressure to the diaphragm via the control element in the first position. The diaphragm is thus held clamped in its initial position, so that a reliable pressure equalization between the interior of the battery housing and the environment is ensured.

Furthermore, it is advantageous if the force-transmitting element applies a tensile force to the membrane via the control element in the second position. In the second position of the control element, the diaphragm is deflected such that it is held in this deflected position by a tensile load.

The force-transmitting member cooperates with the control element in such a way that a preload, under which the spring section of the force-transmitting member bears against the control element, determines a limit value or a limit pressure at which the control element moves from the first position into the second position. In this way, the pressure equalization elements can be easily tuned to the respective installation conditions.

In a preferred embodiment, the destruction element is arranged such that it destroys the membrane after transitioning to and reaching a second position of the control element. In this case, it is advantageous if the membrane is subjected to a tensile force in the second position of the control element. Thus, the membrane can be reliably broken by the breaking element.

The breaking element is advantageously formed by at least one claw provided on the spring section of the force transmission element. It reliably breaks the membrane.

Preferably, the force-transmitting element is arranged on the cover of the pressure equalization element. The force-transmitting member can thus be easily arranged on the pressure equalization element. The housing and the cover can be easily connected to each other in a suitable manner, for example by ultrasonic welding, gluing, bolting, clamping and the like.

The cover is advantageously provided with a central projection in which the force-transmitting element can be accommodated in a space-saving manner.

The projection advantageously protrudes centrally from the conical surface of the closure. This conical surface is preferably configured such that it tapers in the direction of the membrane or the housing.

The projection of the cover is preferably provided with a hole into which the control element protrudes at least in its second position. The control element then protrudes through the projection of the cover in the second position, so that the user of the pressure equalization element can easily ascertain whether an excessively high pressure has been reached in the battery housing.

The control element may be configured such that it does not protrude from the hole of the boss in the first position.

However, it is also possible that the control element protrudes through the hole of the boss both in the first position and in the second position. To mark the first and second positions of the control element in this case, the control element may be colored differently. In this way, the portion protruding in its first position may be colored yellow, for example, while it has another color, for example red, in its second position in which the control element protrudes further from the protruding portion of the cover. It is then also possible to reliably discern whether the control element is in its second position.

The cover advantageously has a gas outlet opening in the edge region. A reliable gas exchange between the battery housing and the environment is then possible.

The housing is also advantageously provided with a gas through-hole, which is in flow connection with the gas outlet opening on the closure side.

In an advantageous embodiment, the control element has a limb extending from the central base body, which limb is provided with a breaking element at the free end. The breaking element of the arm acts on the outer region of the membrane and breaks the membrane partially in this region.

In order to be able to easily ascertain by a user whether the control element has moved into its second position due to an inadmissibly high pressure in the battery housing, the pressure compensation element is advantageously provided with at least one display element.

As the display element, an optical display element may be provided. In this way, the display element can, for example, have at least two different color areas, from which the user can easily ascertain whether the display element has been displaced.

A further advantageous possibility is to configure the display element as an integral part of the control element. Thus, a separate display member is not required.

In a preferred embodiment, a protective screen is provided on the side of the membrane facing away from the control element. It may for example consist of an orifice plate, slot or the like, which has advantages in terms of electromagnetic compatibility (EMV) and may also be used as finger protection.

In order that the membrane is not destroyed, for example, by wires inserted through the gas outlet opening of the cover, the gas outlet opening on the cover side, viewed in the axial direction, is preferably arranged radially next to the membrane. Thus, for example, a wire inserted through the gas outlet does not damage the membrane.

The subject matter of the present application derives not only from the content of the claims, but also from all the data and features disclosed in the figures and description. Even though they are not the subject matter of the claims, they are claimed as important in the present invention whenever they are novel, both individually and in combination, as compared with the prior art.

Further features of the invention are obtained from the further claims, the description and the drawings.

Drawings

The invention is explained in detail below with the aid of the embodiments shown in the drawings. The drawings show:

FIG. 1 is a perspective view of the pressure equalization element of the present invention in an operational position;

FIG. 2 is a perspective and cross-sectional view of the pressure equalization member shown in FIG. 1;

FIG. 3 is an axial cross-section of the pressure equalization member shown in FIG. 1;

fig. 4 to 6 are illustrations of the pressure equalization element according to the invention according to fig. 1 to 3 after the overpressure has been generated;

FIG. 7 is a perspective view of a clamping member of the pressure balance member of the present invention;

fig. 8 and 9 are illustrations according to fig. 3 and 6 of a further embodiment of a pressure equalization element according to the invention;

fig. 10 and 11 are illustrations according to fig. 8 and 9 of a further embodiment of a pressure equalization element of the invention;

fig. 12 and 13 are an axial section and a perspective view, respectively, of the pressure equalization member shown in fig. 10 and 11;

fig. 14 is a side view of the control element of the pressure balancing element shown in fig. 10-13;

fig. 15 is a view of the housing of the pressure equalization element shown in fig. 10-13;

fig. 16 is a view of the closure of the pressure equalization member shown in fig. 10-13;

fig. 17 is a diagram of the diaphragm of the pressure balance element shown in fig. 10 to 13;

fig. 18 is a view of a protective net of the pressure balance member shown in fig. 10 to 13;

fig. 19 is a seal of the pressure balance member shown in fig. 10 to 13;

FIG. 20 is an axial cross-section of another embodiment of a pressure equalization member of the present invention;

FIG. 21 is a partial axial cross-section and a partial perspective view of the pressure equalization member illustrated in FIG. 20;

FIG. 22 is a top view and a perspective view of the cover of the pressure equalization member shown in FIG. 20;

FIG. 23 is a view and perspective of the housing of the pressure balance element shown in FIG. 20;

FIG. 24 is a side view and a perspective view of a control element of the pressure balance element shown in FIG. 20;

FIG. 25 is a diagram and perspective view of a diaphragm of the pressure balance element shown in FIG. 20;

FIG. 26 is an axial cross-section of another embodiment of a pressure equalization member of the present invention;

FIG. 27 is a partial axial cross-section and a partial perspective view of the pressure equalization member illustrated in FIG. 26;

FIG. 28 is an axial view and perspective view of the housing of the pressure balance element shown in FIG. 26;

FIG. 29 is an axial view and a perspective view of the control element of the pressure balance element shown in FIG. 26;

fig. 30 is a diagram and a perspective view of the diaphragm of the pressure balance element shown in fig. 26.

Detailed Description

The pressure equalization element is advantageously used in a battery housing of an electric vehicle to ensure that the air pressure in the battery housing remains approximately constant. If the pressure in the battery housing exceeds a predetermined limit, the pressure equalization element ensures that a rapid pressure equalization between the interior of the battery housing and the environment can take place.

The battery housing (not shown) has an opening into which the pressure equalization element is sealingly inserted. The pressure equalization element has a housing 1, which is preferably cylindrical in shape, and on its side facing the battery housing has an axially projecting ring 2, which protrudes into a mounting opening of the battery housing. The ring 2 defines an inlet E for air. The ring 2 has an outer diameter smaller than the housing 1. In the region radially outside the ring 2, the housing 1 is provided at its underside with an annular groove 3, in which an annular seal 4 (preferably an O-ring) engages. In the installed position, the seal 4 rests sealingly against the outer side of the battery housing with elastic deformation.

The housing 1 is provided with an axially protruding ring 5 on its upper side, the cylindrical outer side 6 of which and the outer circumferential surface 7 of the housing 1 lie in a common cylindrical surface.

As can be seen from fig. 2 and 3, the radial width of the wall of the housing 1 is greater than the radial thickness of the two rings 2 and 5 of the housing 1.

In the axial view, the ring 2 is offset radially inward relative to the ring 5.

At the transition to the ring 2, the cylindrical inner side 8 of the housing 1 is provided with an annular boss 9 which axially defines an annular recess 10 which opens towards the free end of the ring 2. It receives an annular flange 11 of a protective screen 12 which rests against the bottom 13 of the recess 10. The protective screen 12 rests with its radially outer edge on the annular boss 9. The protective screen 12 is configured such that its annular flange 11 does not protrude in the axial direction beyond the ring 2 of the housing 1, but advantageously has a small axial distance from the free end of the ring 2.

As shown in fig. 2, the protection net 12 is provided with through holes 14 which are uniformly distributed on the protection net 12. It can be made of, for example, an orifice plate, which has advantages in terms of EMV, and can also be used as finger guard.

The protective mesh 12 may be firmly attached to the housing 1 in any suitable manner, such as snap-in connection, adhesive, welding and the like.

The ring 5 of the housing 1 defines a receiving space 15 for a gas-permeable, in particular air-permeable membrane 16. It is advantageously composed of PTFE with its outer edge resting against the bottom 17 of the receiving space 15. The diaphragm 16 rests with its outer edge on the inner side of the housing ring 2. The membrane 16 is firmly fastened with its outer edge region to the bottom 17 of the receiving space 15, for example by adhesive bonding, welding or by other means firmly connected to the housing 1.

In the installed position, the diaphragm 16 is advantageously located in a radial plane of the pressure equalization element or housing 1. The protective screen 12, which is arranged at a distance from the membrane 16, is also advantageously located in the radial plane of the housing 1.

The housing 1 has connecting strips 18 extending radially from the inner side 8, which are advantageously arranged uniformly distributed over the circumference of the housing 1. For example, the connecting strip 18 may have an angular separation of 120 °.

The connecting strip 18 connects the central ring 19 to the inner side 8 of the housing 1.

The connecting strip 18 together with the ring 19 is advantageously formed in one piece with the housing 1, in particular from a suitable plastic, such as PP, PA, PBT or the like.

Particularly preferred materials are used which are particularly resistant to thermal damage, such as flame retardant PP, PA, PBT and the like.

The connecting strip 18 and the central ring 19 have the same axial thickness and both lie in radial planes of the housing 1. The air-permeable membrane 16 rests on the connecting strip 18 and the ring 19 and is supported axially by the connecting strip 18 and the ring 19.

Since the membrane 16 and the protective screen 12 can be fitted into the housing 1 from both sides in the axial direction and fastened thereto in a suitable manner, the membrane and the protective screen can be installed simply.

The interspace between the connecting strips 18 forms a passage opening through which a pressure equalization between the interior of the battery housing and the environment via the membrane 16 can be easily achieved.

The control element 20 is fastened to the membrane 16 on the side facing away from the connecting strip 18. It is fastened in the centre of the membrane 16 and is thus located at the level of the ring 19 of the housing 1. When the membrane 16 is deformed under too high an internal pressure in the battery housing and lifted from the connecting strip 18, the control element 20 is correspondingly driven. It has a cylindrical pin 21 which protrudes axially from a base 22. It is provided on the periphery with two faces inclined in axial section, which are advantageously conical surfaces 23, 24, which are arranged inclined in opposite directions to each other and are connected to each other. The conical surface 23 adjacent to the pin 21 tapers in the direction of said pin 21, while the other conical surface 24 tapers in the direction of the membrane 16.

The conical surface 24 adjacent to the membrane 16 is connected to a cylindrical surface 25 of a foot portion 26 which is fastened with widened ends to the membrane 16.

The control element 20 is disposed with a large part of its axial height in the cylindrical projection 27 of the cover 28. The boss 27 is centrally located in the cover 28 and has an end wall 29 with a central aperture 30 into which the pin 21 of the control element 20 extends. The diameter of the hole 30 (fig. 1) corresponds substantially to the outer diameter of the pin 21. The end wall 29 is spaced apart from the base body 22 of the control element 20, with the pressure equalization element intact (fig. 1 to 3). It is therefore provided that the end face 31 of the pin 21 is flush with the outer side 32 of the end wall 29. The end face 31 and the outer side face 32 are advantageously planar and lie in the radial plane of the pressure equalization element.

The boss 27 protrudes from the centre of the conical surface 33 of the cover 28. The conical surface 33 extends obliquely downwards from the outer edge in the direction of the membrane 16, seen in an axial section according to fig. 3.

The cover 28 has a cylindrical outer surface 34 which is turned into a conical surface 33 by a radially extending annular section 35. The outer side 36 of the annular segment 35 is advantageously located in the same radial plane as the outer side 32 of the end wall 29 (fig. 3).

In the annular section 35, passage openings 37 are provided distributed over the circumference, which are advantageously configured to be elongated in the circumferential direction of the annular section 35.

Viewed in the axial direction of fig. 3, the outer jacket surface 34 is spaced from the ring 5 surrounding the housing 1. The axial height of the outer envelope surface 34 is advantageously greater than the axial height of the annular projection 27 of the cover 28. The entire closure 28 is advantageously made in one piece from a suitable plastic.

The outer ring 5 of the housing 1 extends to the conical surface 33 of the cover 28 and is provided with a through-hole 38 which extends through the ring 5 and is arranged on its circumference at a distance back and forth. The through-hole 38 is in flow connection with the through-hole 37 of the cover 28.

The cover 28 and the housing 1 are firmly connected to each other in a suitable manner, such as by gluing, welding or snap-fitting.

In order that the membrane 16 is not destroyed, for example, by wires inserted through the gas outlet opening of the cover, the gas outlet opening on the cover side, viewed axially, is preferably arranged radially next to the membrane. Thus, for example, a wire inserted through the gas discharge port does not damage the diaphragm 16.

At least one force-transmitting element 39, which is advantageously a clamping element 39, is arranged in the annular projection 27 of the cover 28. For cost saving, the clamping element 39 can also be produced by injection molding of plastic together with the cover 28.

The clamping element 39 is of substantially U-shaped configuration (fig. 7) and has a connecting strip 40 which is provided with a centrally arranged opening 41. Through which the pin 21 of the control element 20 protrudes. The connecting strip 40 rests in a planar manner on the underside of the end wall 29 of the boss 27 and is firmly connected thereto. As shown in fig. 3, the clamping element 39 is spaced apart from the cylindrical circumferential surface 42 of the annular projection 27 in the installed position.

The connecting strip 40 of the clamping element 39 connects two respectively shaped legs 43, 44 to one another. They have shaped intermediate sections 45, 46. The two intermediate sections 45, 46 each have an abutment section 47, 48 with which the clamping element 39 abuts against the conical surface 23 or 24 of the control element 20 with elastic deformation of the legs 43, 44.

The clamping part 39 is provided with protruding breaking elements 49, 50 at the free ends of the legs 43, 44, which protrude in the direction of the membrane 16 in the mounted position of the clamping part 39. The breaking elements 49, 50 are, for example, prongs which taper and are arranged at the free edges of the legs 43, 44. The breaking elements 49, 50 may have any suitable shape, such as the shape of a blade.

Fig. 1 to 3 show the pressure compensation element in the operating position. The membrane 16 rests on the connecting strip 18 and the ring 19. The prongs 49, 50 of the clamping member 39 are maintained at an axial distance from the diaphragm 16 (fig. 3). Pressure equalization between the battery housing and the environment can be achieved by means of an air-permeable membrane 16. Air flowing out of the battery housing through the membrane 16 can flow into the environment via the through-holes 38 and through the holes 37. Instead, outside air can flow into the battery housing via these holes 37, 38 and the membrane 16.

As soon as the pressure build-up in the battery housing is so high that the air cannot flow sufficiently through the membrane 16, the membrane deforms under high pressure in the direction of the cover 28 (fig. 4 to 6). The membrane 16 is lifted from the connecting strip 18 and the ring 19. The control element 20, which is firmly connected to the membrane, moves correspondingly in the annular projection 27 of the cover 28. The conical surface 23 of the control element 20 elastically deforms the two legs 43, 44 of the clamping element 39 outwards in opposite directions to one another until the abutment sections 47, 48 come out of the conical surface 23. The legs 43, 44 then rebound again, wherein the contact portions 47, 48 now advantageously contact the conical surface 24 of the control element 20 facing the membrane 16.

The legs 43, 44 of the clamping element 39 and/or the control element 20 can also be designed such that the abutment sections 47, 48 are at a small distance from the conical surface 24 of the control element 20 when the diaphragm 16 is deflected. Advantageously, however, the abutment sections 47, 48 bear against the conical surface 24. The control element 20 is then pressed against the underside 51 of the end wall 29 of the annular projection 27 (fig. 6).

The pin 21 of the control element 20 is pushed outwards through a hole 30 in the end wall 29.

At the transition of the pin 21 to the conical surface 23, a projection 52 is advantageously provided, with which the control element 20 can be positioned on the end wall 29 of the projection 27.

When the membrane reaches the offset position according to fig. 4 to 6, the prongs 49, 50 of the clamping member 23 mechanically break the membrane 16. As a result of the mechanical destruction, the overpressure in the battery housing can be reduced almost instantaneously in such a way that air can flow through the destroyed membrane 16 and out through the openings 37, 38. The cross-sectional area for emergency exhaust is optimized in terms of flow technology.

The holes 37, 38 may be configured to allow for either axial (as shown) or radial emergency venting.

Pressing the control element 20 axially outwards by means of the clamping element 39 in particular contributes to a reliable mechanical destruction of the membrane 16. In this way, it is ensured that the prongs 49, 50 destroy the membrane 16 in the event of an emergency exhaust.

The protruding pin 21 tells the user that an emergency venting has occurred and that the pressure equalization element has to be replaced. The clamping element 39 ensures that the control element 20 does not retract axially again after an emergency exhaust.

In the exemplary embodiment shown, the control element 20 is mounted in such a way that the end face 31 of the pin 21 is flush with the outer face 32 of the end wall 29 of the projection 27 in the operating position. However, the pin 21 may also be configured such that it protrudes outwardly through the hole 30 of the end wall 29 in the normal position, and the protruding portion is color-coded. The section of the pin 21 connected thereto may have a different color than it is, for example red, which color is visible from the outside in the moved position of the pin 21 in the event of an emergency exhaust. Thus, in this embodiment, the control element 20 constitutes a display element at the same time.

The passage opening 37 in the outer annular section 35 of the cover 28 is arranged such that the membrane 16 is not damaged from the outside, for example by means of wires. The passage opening 37 is located radially outside the membrane 16, seen in the axial direction of the pressure equalization element.

The elastic clamping element 39 determines the opening pressure with which the diaphragm 16 is deflected to such an extent that it is destroyed by the prongs 49, 50. The conical surface 23 of the control element 20 and the clamping element 39 or the legs 43, 44 thereof cooperate with one another in such a way that the control element 20 is moved upwards in the manner described when a predetermined opening pressure is reached, so that the diaphragm 16 is driven and deflected.

The cover 28 protects the membrane 16 during the high pressure cleaning process.

Since the clamping element 39 cooperates with the control element 20 and thus with the diaphragm 16, the pressure equalization element can be assembled independently of the position. The cover 28 and the housing 1 can be easily connected to each other by ultrasonic welding, for example. Further connection possibilities are snap-on connections, screw connections and the like.

The design of the cover 28 and the housing 1 is simple so that they can be produced with simple molds, in particular with injection molding.

The pressure equalization element may also be used when there will be an excessive negative pressure in the battery housing. In this case, the connecting strip 18 prevents the diaphragm 16 from being strongly deformed in the direction of the battery case.

Fig. 8 and 9 show a second embodiment of the pressure equalization element. It is constructed substantially the same as the previous embodiment. The end wall 29 of the boss 27 is free of holes and is configured to be closed. On the end wall 29 a magnet piece is provided which can co-act with a magnet piece 54 of the control element 20. The magnet piece 54 is located on the end face of the base body 22 of the control element 20. One of the magnet pieces 54 may be a ferrous part or the like, which is held by the other magnet piece in the second position of the control element 20 (fig. 9).

The magnet pieces 53, 54 are sufficiently spaced from each other in the operating position shown in fig. 8 so that they do not interfere with each other.

The force-transmitting member 39 is connected to the control element 20 according to the previous embodiment.

If the pressure build-up in the battery housing is so high that air cannot flow sufficiently through the membrane 16, the membrane deforms under high pressure in the direction of the cover 28 (fig. 9). As in the previous embodiment, the membrane 16 is lifted from the connecting strip 18 and the ring 19. The control element 20, which is firmly connected to the membrane 16, moves within the annular projection 27 of the cover 28. At the same time, the two legs 43, 44 of the clamping element 29 are elastically deformed outwards in opposite directions to one another until the abutment sections 47, 48 come out of the conical surface 23 of the control element 20. The legs 43, 44 then rebound again, wherein the abutment sections 47, 48 advantageously abut against the conical surface 24 of the control element 20 facing the membrane 16.

The two magnet pieces 53, 54 are arranged such that they attract each other, thereby holding the control element 20 in the moved position (fig. 9).

The membrane 16 is mechanically broken in the manner described by the prongs 49, 50 of the clamping member 39. The overpressure in the battery housing can thus be reduced almost instantaneously in that air can flow through the destroyed membrane 16 and out through the holes 37, 38.

The contact of the two magnet plates 53, 54 can be used to generate corresponding signals which can be transmitted by means of a wired connection or wirelessly to an evaluation unit (not shown). Thus, the overload condition in the battery case can be reliably displayed.

Instead of a magnetic display device, an electrical display device can also be used, which generates a signal when the membrane 16 is deflected in the manner described and destroyed by the clamping element 39.

The magnet pieces 53, 54 ensure that the membrane 16 remains in the raised position shown in fig. 9 and does not return to the initial position shown in fig. 8. The membrane 16 is definitely destroyed by the rise by means of the magnet pieces 53, 54.

The pressure equalization elements shown in fig. 10 to 19 essentially correspond to the embodiments shown in fig. 8 and 9. Unlike this embodiment, the magnet pieces 53, 54 are not provided. Thus, the diaphragm 16 is not held in an offset position by magnetic forces (fig. 11 and 13).

In the operating position (fig. 10 and 12), the membrane 16 rests against the connecting strip 18 and the ring 19 in the manner described. In this position, the control element 20 is connected to the clamping element 39 in the manner described. The abutment sections 47, 48 of the clamping element 39 bear against the conical surface 23 of the control element 20. The prongs 49, 50 are spaced from the diaphragm 16.

The clamping element 39 is fastened with its connecting strip 40 to the inner side of the end wall 29 of the cover 28 in a suitable manner.

The protection net 12 (fig. 12 and 18) has a circular contour according to the previous embodiment and is provided with through holes 14 which are distributed, preferably uniformly distributed, over the face of the protection net 12.

The cover 28 has, at the edges, through holes 37 (fig. 16) arranged in the manner described, at a distance back and forth along the periphery of the cover 28.

The housing 1 is constructed according to the previous embodiment and has an annular groove 3 in which a seal 4 is seated. According to the embodiment described above, it is advantageously formed as a sealing ring with a circular cross section.

If the pressure build up in the battery housing during operation is so high that the air cannot pass through the membrane 16 to the outside rapidly enough in the manner described, the membrane 16 deforms under high pressure in the direction of the cover 28 (fig. 11 and 13). As already explained with the aid of the embodiment shown in fig. 1 to 7, the membrane 16 is destroyed by the prongs 49, 50 of the clamping element 39. Thus, the overpressure in the battery housing can be reduced almost instantaneously. Air from the battery housing can flow through the broken membrane 16 and out through the holes 37, 38.

In the embodiment described below, the pressure equalization element is designed such that the diaphragm 16 is at least partially destroyed by a destruction element arranged on the side of the diaphragm 16 facing the intake side E.

Fig. 21 to 26 show a pressure equalization element with a housing 55, which is preferably cylindrical in shape. It has a cylindrical shell surface 56 which at one end turns into a radially inwardly directed annular flange 57, to which the edge of the diaphragm 16 is fastened. The annular flange 57 is advantageously provided at its free end with a groove 58 in which the edge of the membrane 16 is located. The depth of the recess 58 advantageously corresponds to the thickness of the membrane 16. The membrane is fastened to the bottom of the recess 58 in a suitable manner, for example by means of adhesive, welding and the like.

The membrane 16 has a circular contour and is provided with a central hole 59 into which the control element 20 protrudes in a manner to be described.

Unlike the above-described embodiments, the cover 28, which is essentially configured as a flat disk, is fastened to the end face of the housing surface 56 of the housing 55. The cover 28 is secured to the end face of the shell surface 56 in a suitable manner, such as by adhesive, welding, and the like. The outer edge of the cover 28 is flush with the outer side of the face 56 of the housing 55.

Along the periphery of the flat disc-shaped cover 28, there are passage openings 37 at a distance back and forth for pressure equalization between the battery housing and the environment. The through holes 37 are advantageously configured identically and are arranged at uniform distances along the periphery of the cover 28.

The cover 28 is provided centrally with a hole 60 from the edge of which a latch hook 61 projects inwardly in the direction of the membrane 16. They are uniformly distributed along the perimeter of the aperture 60 and are advantageously constructed integrally with the cover 28.

The locking hook 61 protrudes perpendicularly inwardly from the cover 28 into the housing 55 and is provided at its free end with an inwardly projecting locking projection 62 which has a triangular cross section and cooperates in a manner to be described with a locking element 63 of the control element 20.

The latch hook 61 is advantageously constructed to have a resilient spring force.

The control element 20 has a pin 64 extending from the base body 22, which is advantageously formed integrally with the base body 22. On the pin 64, a latching element 63 is provided, which is advantageously embodied as one piece with the pin 64 and is embodied as a raised circumferential ring having a triangular cross section.

In this embodiment, the pin 64 is provided with two latching elements 63 which are connected to one another.

The base body 22 advantageously has a circular contour and is provided on its upper side facing the diaphragm 16 on the edge side with a circumferential groove 65, into which the radially inner edge 66 of the diaphragm 16 engages. The depth of this recess 65 corresponds to the thickness of the membrane 16. It may be firmly attached to the base 22 of the control element 20 in any suitable manner, such as by adhesive, welding, and the like.

The arms 67 project radially from the base 22, are distributed uniformly over the periphery of the base 22, and taper advantageously in the direction of their free ends (fig. 25). The arm 67 is provided at its free end with a tapering tooth 68 directed towards the membrane 16, which tooth ends in each case with a cutting edge 69.

In the operating position shown in fig. 21 and 22, the teeth 68 of the control element 20 are at a distance from the diaphragm 16. Teeth 68 are located on the side of diaphragm 16 facing away from cover 28.

The latching projections 62 of the latching hooks 61 of the cover 28 bear against the conical surfaces of the latching elements 63 of the adjacent cover 28 facing the cover 28. In this case, the pin 64 of the control element 20 is advantageously designed such that its end face 70 is located in the upper side 71 of the cover 28.

In this case, the pin 64 advantageously also forms a display element, which displays the operating position of the pressure compensation element.

In the operating position of the pressure equalization element, an air equalization between the battery housing and the environment takes place via the air-permeable membrane 16. Air flowing through the membrane 16 reaches the environment via the cover-side passage holes 37. Conversely, external air can also flow into the battery housing via the passage openings 37 and the air-permeable membrane 16.

If the pressure build-up in the battery housing is so high that air cannot flow sufficiently through the membrane 16, the membrane deforms under high pressure in the direction of the cover 28. Since the control element 20 is firmly connected to the membrane 16, it is correspondingly moved and moved in the direction of the interior of the housing 55.

The arm 67 of the control element 20 is configured to point upward from the base 22 in the direction of the diaphragm 16. The length of the arms 67 is such that their teeth 68 are adjacent to the radially outer edge of the diaphragm 16 or adjacent to the inner edge of the annular flange 57 of the housing 55. By this position and arrangement of the projecting arms 67 it is achieved that when the control element 20 is moved, the diaphragm is destroyed in the radially outer region by the cutting edges 69 of the teeth 68. The overpressure in the battery housing can then be reduced almost instantaneously, since air can flow out rapidly via the destroyed membrane 16 and the through-hole 37.

When the control element 20 is moved, the locking hook 61 latches with its latching projection 62 between two latching elements 63 of the control element 20 or under a lower latching element 63 facing away from the cover 28, depending on the distance of movement. The control element 20 is thus held fixedly in this displaced position by the locking hook 61, so that the user can reliably ascertain via the pin 64 extending from the hole 60 whether the membrane 16 has been destroyed by excessive pressure in the battery housing.

Fig. 27 to 30 show a further embodiment of a pressure equalization element, which is distinguished by a simple structure. It has a housing 1 with only a housing face 1a. The diaphragm 16 is fastened with its outer edge to the end face of the shell surface, for example by means of bonding, welding and the like.

The housing 1, and thus the housing face 1a, is advantageously cylindrical in shape.

The control element 20 is arranged in the housing 1, preferably locked in the housing 1.

On the inner side 72 of the shell 1a there is a circumferential raised flange 73, which advantageously has a triangular cross section. The control element 20 can be snapped into the housing 1 by means of the annular flange 73.

The control element 20 has a base body 22 which is embodied as flat and from which latching arms 74 protrude in the radial direction, which advantageously taper in the direction of the free end thereof.

The latching arm 74 is provided at the free end with teeth 75 projecting transversely to the direction of the membrane 16, which teeth are each terminated by a cutting edge 76.

The tooth 75 has an outer surface 77 with which it rests flat against the inner surface 72 of the shell surface 1a of the housing 1 (fig. 27 and 28). The outer surface 77 is configured to be curved in the circumferential direction of the housing surface 1a, so that it can reliably abut against the inner surface 72 of the housing surface 1a.

In the outer side 77 of the teeth 75, grooves 78 are respectively present, which extend over the width of the teeth 75 and into which the annular collar 73 of the housing 1 engages. The groove 78 and the annular flange 73 are configured to be mutually identical.

Centrally, a sleeve-shaped fastening element 79 protrudes from the base body 22 of the control element 20, to the end face of which fastening element the membrane 16 is fastened, for example by means of adhesive bonding, welding or the like.

In the operating position shown in fig. 27 and 28, the cutting edge 76 of the control element 20 is at a small distance from the membrane 16.

Pressure equalization between the battery housing and the environment is achieved by means of a gas-permeable membrane 16. The latching arms 74 of the control element 20 are sufficiently spaced from one another to form sufficiently large gas passages therebetween that allow for smooth gas exchange between the battery housing and the environment.

If the pressure build up in the battery housing is so high that air cannot flow sufficiently through the membrane 16, the membrane flexes outwardly under the action of the high pressure. The control element 20 is driven by the fastener 79. The annular flange 73 and the recess 78 of the control element 20 are designed due to their triangular cross-sectional design such that the control element 20 is released from the latch when the diaphragm 16 is deformed. The membrane 16 is destroyed by the cutting edge 76 of the control element 20, so that an air equalization between the battery housing and the environment can take place very quickly.

Since the cutting edge 76 is arranged in the region of the inner side 72 of the housing face 1a of the housing 1 and is only at a small distance from the membrane in the operating position, it is ensured that said cutting edge 76 reliably breaks the membrane 16. In addition, the teeth 75 are guided on the inner wall 72 when the control element 20 is moved, also contributing to this purpose.

Claims

1. A pressure equalization element for a battery housing, having: -a housing (1, 55) having at least one inlet (E) for a gas, preferably air; and at least one air-permeable membrane (16), characterized in that: the membrane (16) is firmly connected to at least one control element (20) which can be moved from a first position into a second position beyond a predetermined pressure difference and which brings about the membrane (16), and at least one breaking element (49, 50;68; 75) is provided in the movement path of the membrane (16) which at least partially breaks the membrane (16) when the membrane (16) is displaced.

2. A pressure equalization element as recited in claim 1, wherein: the control element (20) is fastened centrally on the upper or lower side of the membrane (16).

3. The pressure equalization element of claim 1 or 2, wherein: the breaking element (49, 50) is a component of a force-transmitting member (39) that acts upon the control element (20) in the first position.

4. A pressure equalization element as recited in claim 3, wherein: the force-transmitting element (39) acts on the control element (20) in the second position.

5. The pressure equalization element of claim 1 or 2, wherein: the destruction element (68; 75) is a component of the control element (20).

6. A pressure balancing member according to any one of claims 3 to 5, wherein: the control element (20) has two inclined surfaces (23, 24) which are opposite to each other, preferably conical surfaces, against which the force-transmitting element (39) rests with spring sections (43, 44) under the action of spring force at least at the transition between the two positions of the control element (20).

7. The pressure equalization element of claim 6, wherein: the force-transmitting element (39) is embodied in a substantially U-shape, the legs of which form spring sections (43, 44).

8. The pressure equalization element of claim 6 or 7, wherein: the spring section (43, 44) of the force transmission element (39) has an abutment section (47, 48) which, under elastic prestress, abuts against the inclined surface (23) of the control element (20) at least in the first position thereof.

9. A pressure balancing member according to any one of claims 3 to 8, wherein: the force-transmitting element (39) exerts a tensile force on the membrane (16) by means of the control element (20) in the second position.

10. The pressure balancing element of any one of claims 6 to 9, wherein: the pre-tensioning force, under which the spring sections (43, 44) of the force-transmitting element (39) bear against the control element (20), determines a limiting pressure at which the control element (20) can be moved from the first position into the second position.

11. The pressure balancing element of any one of claims 1 to 10, wherein: the breaking element (49, 50) is arranged such that it breaks the membrane (16) after transitioning to and reaching a terminal position of the control element (20) in the second position.

12. The pressure balancing element of any one of claims 6 to 11, wherein: the breaking element (49, 50) is a claw provided on a spring section (43, 44) of the force-transmitting element (39).

13. A pressure balancing member according to any one of claims 3 to 12, wherein: the force-transmitting element (39) is arranged on the cover (28) of the pressure equalization element.

14. A pressure equalization element as recited in claim 13, wherein: the cover (28) has a central projection (27) in which a force-transmitting element (39) is arranged.

15. A pressure equalization element as recited in claim 14, wherein: the boss (27) protrudes centrally from the conical surface (33).

16. The pressure equalization element of claim 14 or 15, wherein: the projection (27) is provided with a hole (30) into which the control element (20) protrudes at least in the second position.

17. A pressure balancing member according to any one of claims 13 to 16, wherein: the cover (28) has a gas outlet (37) in the edge region.

18. A pressure balancing member according to any one of claims 13 to 17, wherein: the housing (1) is provided with a gas through-hole (38) which is in flow connection with a gas outlet (37) on the closure side.

19. A pressure balancing member according to any one of claims 1 to 18, wherein: the control element (20) has a limb (67, 74) extending from the central base body (22), which limb is provided with a breaking element (68, 75) at the free end.

20. A pressure balancing member according to any one of claims 1 to 19, wherein: the pressure equalization element has at least one display element (21; 53, 54; 64).

21. A pressure equalization element as recited in claim 20, wherein: the display element (21; 64) is an optical display element.

22. A pressure equalization element as recited in claim 20, wherein: the display element (21) is an integral part of the control element (20).

23. A pressure balancing member according to any one of claims 1 to 20, wherein: the control element (20) is an electronic and/or magnetic display element.

24. A pressure balancing member according to any one of claims 1 to 23, wherein: a protective screen (12) is provided on the side of the membrane (16) facing away from the control element (20).

25. A pressure balancing member according to any one of claims 1 to 24, wherein: the cover-side gas outlet (37) is located radially next to the diaphragm (16) as viewed in axial view.