High-voltage battery, its manufacture and use, and motor vehicle with such a battery

Abstract

High-voltage battery with the following features: — the high-voltage battery has a housing (10) which is designed for filling with coolant (11), — the housing (10) contains at least one battery cell (12) with a degassing valve (13), which is arranged within the housing in such a way that the coolant (11) can flow around the battery cell away from the degassing valve, and — the housing (10) has a degassing opening provided with a seal into which the degassing valve (13) opens, characterized by the following features: — the seal has a first sealing lip (14) which fits snugly against the battery cell (12) and surrounds the degassing valve (13), and — the seal has a second sealing lip (14) which fits snugly against the housing (10) and surrounds the venting opening.

Description

[0001] The present invention relates to a high-voltage battery. The present invention also relates to its production, its use, and a motor vehicle. State of the art

[0002] Modern electric vehicles primarily use lithium-ion batteries, which consist of a large number of individual battery cells. These battery cells are usually housed in a common housing, also known as a battery module. The battery cells within such a module are typically designed to safely vent in the event of overheating, for example, due to a short circuit or similar malfunction. For this purpose, each cell is equipped with a vent, which opens the cell when a certain internal pressure is reached, allowing the hot gases to safely escape from the cell's interior.

[0003] To absorb the escaping gases, the battery module is provided with corresponding vents or vents, which are usually located directly below the vent valves of the individual cells. These vents are sealed during normal operation to prevent the coolant, which serves to regulate the temperature of the cells, from escaping. In many cases, a vent seal is used for this purpose. This seal is inserted into the vent and securely seals it during normal operation.

[0004] To perform the above-mentioned functions, especially for the safe degassing of the cells in the event of overheating and for the sealing of the vent openings during normal operation, various design and material requirements must be met. For example, the materials used must be able to withstand high temperatures while also providing sufficient sealing against the cooling medium. Furthermore, the components used must be designed to provide the necessary mechanical stability and durability.

[0005] Various solutions to this problem are known from the prior art. One common method involves equipping the vent openings with special sealing elements made of heat-resistant materials. These sealing elements can be designed, for example, as O-rings that are inserted into a corresponding groove in the vent opening. In other embodiments, the sealing elements can also be designed as flat gaskets that are placed over the vent opening and pressed against the battery module by a screw connection or similar means.

[0006] DE 102018200254 A1 describes a safety valve with a receiving groove defined by two webs. The first web faces away from the receiving groove and has a ramp. This design allows the first web to elastically rebound when the safety valve is pressed into the housing opening or onto the receiving socket.

[0007] WO 2013121990 A1 describes an explosion-preventing valve consisting of an annular housing made of synthetic resin, an O-ring for sealing the gap between the explosion-preventing housing and a packing housing, and a venting membrane shaped as a round disc attached to the housing to close a central opening in the explosion-preventing housing. Furthermore, stop nails are provided, each of which has a suspension part swollen in the direction of the outer diameter at the tip and is elastically deformable in the diameter direction thanks to the elasticity of the synthetic resin material.

[0008] EP 3739664 A1 describes a safety valve for an electrochemical device that is mounted over an opening in the device housing by means of a clip mechanism. Protective degassing elements made of thin, sheet-like material are mounted in openings at the lower part of the safety valve. These openings provide a gas passage when a certain pressure and / or temperature in the device housing is exceeded. The safety valve also includes sealing elements, such as O-ring seals, and a protective upper cover that forms a cavity. Furthermore, the safety valve has a pressure equalization area formed by a gas-permeable membrane that compensates for minor pressure differences between the interior of the device housing and the environment.

[0009] CN 202930452 U describes an explosion-proof valve for the vent opening of a battery pack.

[0010] US 9669496 B2 describes an explosion-proof valve made of an elastic material such as rubber or resin. It has a cylindrical tubular portion inserted into a hole. Integrated into one end of the tubular portion is an annular outer flange that engages with the edge of the hole outside the container. Integrated into the other end of the tubular portion is an annular locking projection that engages with the edge of the hole inside the container. A diaphragm is integrated inside the tubular portion and at one end in the axial direction. This diaphragm opens and releases the pressure when the internal pressure exceeds a predetermined value. Disclosure of the invention

[0011] One problem is that existing seals do not provide reliable and permanent protection against the cooling medium escaping from the housing. This medium is used to regulate the temperature of the cells and must not escape from the housing during normal operation. However, existing sealing systems often offer only limited sealing effectiveness, especially when exposed to significant temperature fluctuations or pressure changes. This can lead to the cooling medium escaping from the housing despite the seal, which can impair cooling performance and possibly even damage the battery cells.

[0012] Second, the seals must provide a safe venting path for the hot gases in the event of cell overheating. However, existing sealing systems are often unable to meet these requirements. In particular, the sealing elements can be damaged by the hot gases, which can impair their sealing performance.

[0013] Another problem is that the seals must also accommodate a certain degree of tolerance compensation. Since the battery cells and the housing are usually manufactured separately, minor dimensional deviations can occur during assembly of the cells in the housing. The seals must be able to compensate for these deviations to ensure a permanent and secure seal of the vent openings.

[0014] In addition, the seals must be designed to exert minimal pressure on the cell. Excessive contact pressure could damage the cell casing and thus the vent valve, potentially compromising the battery's safety and performance.

[0015] Ultimately, the seals should be simple and cost-effective to manufacture and assemble. However, many existing sealing systems require significant manufacturing and assembly effort, increasing the cost and complexity of battery production.

[0016] The described problem is solved by a high-voltage battery, methods for its production and use, and a motor vehicle according to the independent claims.

[0017] This approach offers the advantage of a sealing effect that is reinforced in both axial and radial directions by the operating pressure of the cooling system. This results in effective sealing even under significant temperature fluctuations or pressure changes.

[0018] In addition, the solution presented here offers effective tolerance compensation in both axial and radial directions. The flexible sealing lips adapt to the respective position of the cell and the housing, thus compensating for any dimensional deviations. This reduces the risk of leaks and increases the reliability and longevity of the seal.

[0019] Furthermore, the seal presented here is designed to exert minimal contact pressure on the battery cell. This protects the cell casing and the venting valve, thus contributing to the safety and performance of the battery.

[0020] The innovative seal can also be made of heat-resistant materials that retain their function even if the cells overheat. This improves the battery's safety in the event of a failure and ensures that the hot gases can escape safely from the cell interior.

[0021] Finally, the presented solution is characterized by simple and cost-effective manufacturing and assembly. The simple design and use of standardized materials allow the seals to be produced and assembled efficiently, reducing the cost and complexity of battery production.

[0022] Further advantageous embodiments of the invention are specified in the dependent patent claims. Short description of the drawings Fig. 1 shows a schematic diagram of the seal. Fig. 2 shows the detail A according to Fig. 1. Fig. 3 shows the detail A according to Fig. 1 in an alternative embodiment. Embodiments of the invention

[0023] The invention will now be explained with reference to the figures. Fig. 1 shows the schematic diagram of a high-voltage battery, the housing (10) of which is filled with coolant, which flows around the battery cell (12) located inside the housing (10) - with the exception of its degassing valve (13).

[0024] To securely seal the venting valve (13), a special seal is used. This seal has two special sealing lips (14). The first sealing lip rests against the battery cell housing (12) and encloses the venting valve (13) axially. The second sealing lip rests radially, i.e., circumferentially, against the battery housing (10). Both sealing lips (14) are designed to compensate for pressure differences and dimensional tolerances and always maintain a slight preload.

[0025] This preload prevents the coolant (11) from immediately leaking out when the housing (10) is filled, as the sealing lips (14) are already in contact with the coolant at a low contact pressure. If the pressure inside the housing (10) is now increased, for example, to a value of approximately 3.5 bar, the sealing lips (14) press even more firmly against their contact surfaces, thus improving the sealing effect.

[0026] The seal also features a ring (15) that surrounds the vent opening, serves as a support element, and forms a stable wall in the radial direction. This ring (15), which can be made of a heat-resistant plastic material, for example, prevents the seal from being radially compressed by the coolant (11). Furthermore, the ring (15) protects the seal from the hot gases during a venting process.

[0027] Fig. 2 shows the detail A according to Fig. 1. Here you can see that the ring (15) opposite the degassing valve (13) is covered by a membrane (18) which protects the cell vent from the environment (salt spray, etc.) but opens under defined conditions. This membrane (18) is formed integrally with the sealing lips (14). The ring (15) also forms a stop (19) for the seal on the cell (12) side. Since this seal has an open profile outside the ring (15), the second sealing lip (14) has a circumferential locking lug (16) which rests on the inside of the housing (10) and prevents the seal from slipping out in the axial direction.

[0028] Fig. 3 shows the detail A according to Fig.1 in an alternative embodiment. In this embodiment, the first and second sealing lips (14) are connected to each other on both sides to form a hose. The seal has a plurality of inlet openings (17) for the coolant (11) on the outside, which open along the ring (15) between the housing (10) and the battery cell (12).

[0029] During the manufacture of the high-voltage battery, the cell (12) is inserted into the housing (10). The seal is inserted axially relative to the ring (15) in the direction of the cell (12) until it reaches the stop (19) in the vent opening, while the ring (15) supports the sealing lips (14) radially inward, and their spring force compensates for any tolerances—for example, regarding the diameter of the vent opening.

[0030] After inserting the cell (12) and the seal, the housing (10) is filled with the coolant (11). The sealing lips (14) prevent the coolant (11) from flowing through the vent opening due to their spring force. Before inserting the seal, the sealing lips (14) are vulcanized to the ring (15).

[0031] During operation, the coolant (11) is pressurized, exerting a compressive force (21) on the sealing lips (14) that is parallel to the spring force. If the battery cell (12) overheats, its vent valve (13) opens and the membrane (18) bursts, allowing escaping gas to escape from the housing (10) through its vent opening. The seal prevents the coolant (11) from penetrating the gas, and the ring (15) protects the sealing lips (14) from the escaping gas. List of reference symbols 10 housings 11 Coolant 12 battery cells 13 Degassing valve 14 Sealing lip 15 rings 16 locking lug 17 Entrance opening 18 Membran 19 stop 20 direction 21 Compressive force A Detail QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] DE 102018200254 A1

[0006] WO 2013121990 A1

[0007] EP 3739664 A1

[0008] CN 202930452 U

[0009] US 9669496 B2

[0010]

Claims

[1] High-voltage battery with the following features: - the high-voltage battery has a housing (10) which is designed for filling with coolant (11), - the housing (10) contains at least one battery cell (12) with a degassing valve (13), which is arranged within the housing in such a way that the coolant (11) can flow around the battery cell away from the degassing valve, and - the housing (10) has a degassing opening provided with a seal into which the degassing valve (13) opens, characterized by following features: - the seal has a first sealing lip (14) which fits snugly against the battery cell (12) and surrounds the degassing valve (13), and - the seal has a second sealing lip (14) which fits snugly against the housing (10) and surrounds the venting opening. [2] High-voltage battery according to claim 1, characterized by following features: - the seal comprises a shape- and heat-resistant ring (15) and - the first and second sealing lips (14) are connected to one another via the ring (15) in such a way that the first sealing lip exerts a spring force directed axially towards the battery cell (12) with respect to the ring and the second sealing lip exerts a spring force directed radially outwards. [3] High-voltage battery according to claim 2, characterized by following features: - the seal has an open profile outside the ring (15) and - the second sealing lip (14) has a locking lug (16) which rests on the inside of the housing (10). [4] High-voltage battery according to claim 2, characterized by following features: - the first and second sealing lips (14) are connected to each other on both sides to form a hose and - the seal has on the outside a plurality of inlet openings (17) for the coolant (11), which open along the ring (15) between the housing (10) and the battery cell (12). [5] High-voltage battery according to one of claims 2 to 4, characterized by following features: - the ring (15) is covered by a membrane (18) opposite the degassing valve (13) and - the membrane (18) is formed integrally with the sealing lips (14). [6] High-voltage battery according to claim 5, characterized by following features: - the ring (15) forms a stop (19) for the seal on the side of the cell (12) and - the ring (15) and the stop (19) are made of elastomer. [7] Production of a high-voltage battery according to claim 6, characterized by following features: - the cell (12) is inserted into the housing (10), - the seal is inserted axially in the direction of the cell (12) up to the stop (19) into the vent opening with respect to the ring (15), while the ring (15) supports the sealing lips (14) radially inwards and their spring force compensates for any tolerances, and - after inserting the cell (12) and the seal, the housing (10) is filled with the coolant (11), while the sealing lips (14) prevent the coolant from flowing out through the vent opening due to their spring force. [8] Production according to claim 7, characterized by following feature: - Before inserting the seal, the sealing lips (14) are joined to the ring by vulcanization. [9] Use of a high-voltage battery according to claim 5 or 6, characterized by following features: - the coolant (11) is put under operating pressure so that it reinforces the seal by exerting a pressure force (21) on the sealing lips (14) that is equal to the spring force, and - if the battery cell (12) overheats, its venting valve (13) opens and the membrane (18) bursts, so that escaping gas escapes from the housing (10) through its venting opening, while the seal prevents the coolant (11) from entering the gas, and the ring (15) protects its sealing lips (14) from the escaping gas. [10] Motor vehicle with a high-voltage battery according to one of claims 1 to 6.

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