Pressure equalization device

Abstract

The invention relates to a pressure equalization device for a housing, in particular a battery housing, comprising a base part (2) made of plastic, a cover (3) which is made of metal and is oriented towards an outer side of the housing, and a valve element (4) for emergency opening, wherein the valve element (4) is arranged on the base part (2) and seals against a sealing seat (5) on the base part (2), and wherein a press-fit connection (6) is formed between the base part (2) and the cover (3).

Description

[0001] January 12, 2026

[0002] Applicant: Carl Freudenberg KG, 69469 Weinheim

[0003] Pressure equalization device

[0004] Description

[0005] The present invention relates to a pressure equalization device for a housing, in particular a battery housing, and especially a battery housing for a vehicle. Vehicles equipped with a rechargeable battery as an energy storage device typically have battery housings containing a plurality of battery cells. During normal operation, temperature and / or pressure changes can occur inside the battery housing, for example, when the vehicle is driven uphill. Pressure equalization can be achieved using a membrane, as disclosed, for example, in DE 102017003360 B3. This document further discloses a possibility of emergency venting by means of an additional elastomer shield connected in parallel to the membrane. In an emergency, the pressure equalization device can open via the elastomer shield to prevent an excessive pressure increase inside the battery housing, for example, during uphill driving.to prevent a fire in one or more battery cells. This is intended, in particular, to protect still intact, adjacent battery cells or parallel battery housings, thus minimizing the risk of further spread and damage to other battery cells. Known pressure equalization devices are often made entirely of plastic or entirely of metal. However, in a battery fire as described, very high temperatures can occur, potentially destroying a solid structure in the plastic pressure equalization device and allowing external access to the battery. Furthermore, it has been found that improper handling when mounting a plastic pressure equalization device on a typically metallic battery housing can lead to damage to the plastic of the pressure equalization device.In pressure equalization devices made entirely of metal, secure and permanent attachment of the diaphragm is particularly difficult. Furthermore, such metallic pressure equalization devices are very heavy. The object of the present invention is to provide an improved pressure equalization device and a housing arrangement which, while being simple and cost-effective to manufacture, also prevents external intervention in the housing after a possible partial destruction of the pressure equalization device.

[0006] This problem is solved by a pressure equalization device having the features of claim 1. The dependent claims describe preferred embodiments of the invention.

[0007] The pressure equalization device according to the invention for a housing, in particular a battery housing, with the features of claim 1, has the advantage that, in addition to the integration of an opening, in particular for emergency venting, a fixed metal substructure is provided which, in particular, remains reliably above the opening in the housing where the pressure equalization device is arranged, even in the event of emergency venting and especially in the event of a battery fire. Furthermore, the pressure equalization device according to the invention is very easy to install and enables a particularly secure connection to a metallic housing without the pressure equalization device being damaged during installation on the housing.

[0008] This is achieved according to the invention by the pressure equalization device for a housing comprising a base body made of plastic and a cover made of metal. The metal cover faces an outer side of the housing. Furthermore, the pressure equalization device includes a valve element for an opening connecting an inner side to an outer side, in particular for an emergency opening, wherein the valve element is fixed to the base body and seals against a sealing seat on the base body. A press fit is also formed between the plastic base body and the metal cover. This ensures a simple and secure connection between the metal cover and the plastic base body. The press fit connects the two components quickly and easily.Furthermore, the separate metal cover offers the possibility of providing different metal covers for different enclosure manufacturers, depending on the specified requirements and / or design wishes of the enclosure manufacturer.

[0009] The metallic cover preferably includes a fixing device for securing the pressure equalization device to the housing. The fixing device preferably comprises one or more bushings that are integrally formed with the cover. The press fit between the fixing device and the base body is preferably made of plastic. The pressure equalization device preferably includes a venting element for continuous ventilation of the housing. This provides continuous ventilation.

[0010] Preferably, the ventilation element is arranged on the base body. The ventilation element is preferably a membrane, a nonwoven fabric, or the like. Particularly preferably, the ventilation element is connected to the plastic base body by means of a first weld. The connection between the ventilation element and the base body can be made by means of a welding process, e.g., an ultrasonic welding process.

[0011] Preferably, the base body comprises at least a first part and a second part. Both parts are made of plastic. Particularly preferably, the first part and the second part are joined together by means of a second weld. Alternatively, the first and second parts of the base body are joined by means of a positive-locking and / or force-locking connection, in particular a clip connection.

[0012] The valve element intended for emergency opening is preferably fixed between the first and second parts of the base body by means of a clamping connection. Alternatively, the valve element is connected to a part of the base body by means of a further welded connection.

[0013] To ensure a secure seal of the pressure equalization device on the housing, the pressure equalization device also has an elastomer seal which rests on an outside of the housing.

[0014] Preferably, the pressure equalization device includes a protective element arranged on a side of the device facing the inside of the housing. This protective element is preferably a wire mesh. Its purpose is to prevent solid particles, which may also escape during a battery fire and be propelled against the inside of the pressure equalization device, from entering the device. The protective element also prevents flames from directly impacting the plastic base body in the event of a battery fire. This provides better protection for the plastic base body.

[0015] Furthermore, the present invention relates to a housing arrangement comprising a metal housing, in particular a battery metal housing, and a pressure equalization device according to the invention. A preferred embodiment of the invention is described in detail below with reference to the accompanying drawing. The drawing shows:

[0016] Fig. 1 shows a schematic, perspective view of a pressure equalization device according to a preferred embodiment of the invention.

[0017] Fig. 2 is a schematic top view of the pressure equalization device of Fig. 1, Fig. 3 is a schematic bottom view of the pressure equalization device of Fig. 1, Fig. 4 is a schematic sectional view of the pressure equalization device of Fig. 1, Fig. 5 is a schematic exploded view of the pressure equalization device of Fig. 1.

[0018] 1,

[0019] Fig. 6 is a schematic, partially cutaway view of the pressure equalization device of Fig. 1 to illustrate the continuous venting and aeration function, and Fig. 7 is a schematic, partially cutaway view of the pressure equalization device of Fig. 1 to illustrate the emergency opening function.

[0020] Below, with reference to Figures 1 to 7, a pressure equalization device I for a metallic housing 101, in particular a battery metal housing, and a housing arrangement 100 are described in detail.

[0021] As can be seen from Figures 1 and 4, the pressure equalization device 1 comprises a base body 2 made of plastic and a cover 3 made of metal. The cover 3 faces an outer surface II of the pressure equalization device or housing 101, and the base body 2 faces an inner surface 12.

[0022] The pressure equalization device 1 is designed to be arranged via a through-opening 102 in the housing 101 and to be connected to it, e.g. by means of screws.

[0023] The pressure equalization device further comprises a ventilation element 7, which is designed for continuous ventilation and venting and corresponding pressure equalization between the inner surface 12 and the outer surface 11. The ventilation element 7 is preferably a non-woven element such as a nonwoven fabric and may comprise one or more layers.

[0024] The pressure equalization device 1 further comprises a valve element 4 for emergency opening, which is fixed to the base body 2. The valve element 4 seals against a sealing seat 5 (see Figures 4 and 6) on the base body. The valve element 4 is made of an elastomer material and has a shield-like shape. Thus, the pressure equalization device 1 is made of two different materials, namely a metal material, in particular aluminum, and a plastic material, in particular a polymer. A press fit 6 is formed between the base body 2 and the cover 3 (see Figure 4).

[0025] As can be seen in detail in Fig. 4, the cover 3 has a fixing device 30 in the form of an integrated bushing. A press fit 6 is formed between an outer circumference of the fixing device 30 and a through-hole 20 (see Fig. 5) in the base body 2. This makes it possible for the pressure equalization device 1 to be firmly connected to a metallic housing, for example, via a screw connection. Since the connection between the pressure equalization device 1 and the metallic housing is only made via the metallic bushings of the fixing device 30, it can be ensured that the metallic cover 3 always remains over the opening in the housing, even if the plastic of the base body melts and / or burns. This prevents unauthorized access to the interior of the housing, even if the base body 2 has melted.

[0026] The fixing device 30 thus has two functions. Firstly, the function of a firm connection between the metallic cover 3 and the base body 2 made of plastic by means of the press connection 6, and secondly, the fixing of the pressure equalization device 1 to the housing 101, e.g. by means of a screw connection.

[0027] As can be seen particularly in Fig. 5, the base body 2 is made of a first part 21 and a second part 22. A fixed connection, e.g. a welded joint or a form-fit and / or force-fit connection, such as a clip connection, is made between the first part 21 and the second part 22.

[0028] The ventilation element 7, in the form of a nonwoven fabric or the like, can be easily and securely connected to the plastic of the base body 2, for example, by means of a first weld 70 such as an ultrasonic weld. This allows for a simple and secure connection of the ventilation element 7 to the base body 2. Figure 4 schematically shows the first weld 70 between the ventilation element 7 and the first part 21 of the base body 2. Alternatively, the ventilation element, in particular a nonwoven fabric, can be fixed to the base body 2 by means of a further fastening component, e.g., a ring.

[0029] The first part 21 is connected to the second part 22 by means of a second weld 80 (see Fig. 4). Preferably, the first and second welds are made simultaneously. As can be seen further in Figures 4, 6, and 7, the valve element 4 is clamped between the first part 21 and the second part 22 of the base body 2 at a clamping connection 10. This can be done, for example, during the pre-assembly of the base body 2. Alternatively, the valve element 4 can also be connected to one or both parts 21, 22 of the base body by means of a further weld. The further weld can preferably be made simultaneously with the first and second welds 70, 80.

[0030] To prevent damage from solid particles that may be generated during a battery fire and thrown against the inside of the pressure equalization device 1, the pressure equalization device 1 also features a protective element in the form of a wire mesh (see Figures 4 and 5). The wire mesh is relatively fine-meshed and thus prevents solid particles from directly impacting the plastic base body and, in particular, the valve element 4, and causing damage there.

[0031] Furthermore, the pressure equalization device comprises an elastomer seal 9, which is arranged in a ring shape on an inner side of the base body 2. In the assembled state, the elastomer seal 9 seals against an outer side of the housing 101.

[0032] Figures 6 and 7 schematically illustrate the basic operating principle of the pressure equalization device. Figure 6 shows the normal pressure equalization via the venting element 7, as indicated by arrows A, which represent venting of the housing, and arrows B, which represent venting of the housing. Venting and aeration occur via openings between the base body 2 and the cover 3 and openings 31 in the cover 3. As can be seen in Figure 2, the openings 31 are formed along the outer circumference of the cover. As further shown in Figure 6, the valve element 4 is made of elastomer and seals securely against the sealing seat 5 when closed.

[0033] Fig. 7 shows an emergency opening function of the pressure equalization device 1, which can occur, for example, in the event of a cell fire among battery cells inside the housing 101. In such a case, a large volume of gas is released within a short time, and the pressure inside the battery housing can rise accordingly. The valve element 4 is designed such that, once a predetermined pressure difference between the inner surface 12 and the outer surface 11 is reached, an emergency opening is performed by the valve element 4. As schematically indicated by arrows C in Fig. 7, a large quantity of gas can thus escape through the openings 31 in the cover 3 via the emergency-opened valve element 4. This prevents further damage and, in particular, further fires of still intact battery cells in the battery housing.

[0034] Thus, the cover 3 can span the opening in the battery housing and be securely screwed to the housing by means of the socket-like fixing devices 30. This ensures a continuous metallic connection between the pressure equalization device 1 and the housing 101, so that the metallic connection remains intact even if the plastic material melts. At the same time, manufacturing advantages can be achieved, in particular through the welded connection of the ventilation element 7 to the base body 2 and the fixing of the umbrella-like valve element 4.

[0035] Since the base body 2 is made of plastic, the two parts 21 and 22 of the base body, the valve element 4, and the ventilation element 7 can form a pre-assembled unit. This makes it possible, for example, to provide different metal covers for different battery manufacturers, which can be designed according to the battery manufacturer's requirements. The standardized interface at the press connection 6 allows for easy interchangeability of the covers for different battery manufacturers.

[0036] It should be noted that it is of course also conceivable that the pressure equalization device 1 may only be designed as burst protection for emergency opening without ventilation element 7.

Claims

8 Claims 1. Pressure equalization device for a housing, in particular a metallic battery housing, comprising a base body (2) made of plastic, a metal lid (3) which faces an outside of the housing, and a valve element (4) for opening, in particular for emergency opening, wherein the valve element (4) is arranged on the base body (2) and seals against a sealing seat (5) on the base body (2), and wherein a press connection (6) is formed between the base body (2) and the cover (3).

2. Pressure equalization device according to claim 1, wherein the cover has a fixing device (30) for fixing the pressure equalization device to the housing.

3. Pressure equalization device according to claim 2, wherein the press connection (6) is formed between the fixing device (30) and the base body (2).

4. Pressure equalization device according to one of the preceding claims, further comprising a ventilation element (7) configured for continuous gas exchange between an inner side (12) and an outer side (11) of the pressure equalization device.

5. Pressure equalization device according to claim 4, wherein the ventilation element (7) is fixed to the base body (2), in particular by means of a first welded connection (70).

6. Pressure equalization device according to one of the preceding claims, wherein the base body (2) has a first part (21) and a second part (22) which are firmly connected to each other.

7. Pressure equalization device according to claim 6, wherein the first part (21) is connected to the second part (22) by means of a second weld connection (80) or wherein the first part (21) is connected to the second part (22) by means of a positive and / or force-fit connection, in particular a clip connection.

8. Pressure equalization device according to claim 6 or 7, wherein the valve element (4) is fixed between the first part (21) and the second part (22) by means of a clamping connection (10).

9. Pressure equalization device according to any of the preceding claims, further comprising an elastomer seal (9) which is arranged on the base body (2), wherein the elastomer seal (9) is configured to seal against an outer wall of the housing.

10. Pressure equalization device according to one of the preceding claims, further comprising a protective element (8), in particular a wire mesh, which is arranged on a side of the base body (2) facing inwards (12), wherein the protective element (18) is configured to protect the pressure equalization device from solids.

11. Housing arrangement (10) comprising a metal housing and pressure equalization device according to one of the preceding claims.

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