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) designed for filling with coolant (11), - the housing (10) contains at least one battery cell (12) with a degassing valve (13) which is arranged inside 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 fitted with a seal, into which the degassing valve (13) opens, - the seal has a first sealing lip (14) that fits snugly against the battery cell (12) and surrounds the degassing valve (13), - the seal has a second sealing lip (14) that fits snugly against the housing (10) and surrounds the degassing opening, - the seal includes a dimensionally stable and heat-resistant ring (15) and - the first and second sealing lips (14) are connected to each other via the ring (15) in such a way that the first sealing lip exerts a spring force directed axially to the battery cell (12) with respect to the ring and the second sealing lip exerts a spring force directed radially outwards, characterized by the 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 several inlet openings (17) on the outside for the coolant (11), which open along the ring (15) between the housing (10) and the battery cell (12).

Description

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

[0002] Modern electric vehicles primarily use lithium-ion batteries, which consist of numerous individual battery cells. These battery cells are typically housed in a common casing, 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 that opens when a certain internal pressure is reached, allowing the hot gases to escape safely.

[0003] To accommodate escaping gases, the battery module is equipped with corresponding degassing or vent openings, which are typically located directly below the degassing valves of the individual cells. These vent openings are sealed during normal operation to prevent the escape of the cooling medium used to regulate cell temperature. In many cases, a vent seal is used for this purpose; it is inserted into the vent opening and securely closes it during normal operation.

[0004] To perform the aforementioned functions, particularly the safe degassing of the cells in case of overheating and 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 simultaneously providing sufficient sealing against the cooling medium. Furthermore, the components used must be designed to exhibit the necessary mechanical stability and durability.

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

[0006] WO 2012 / 147 150 A1, DE 10 2023 100 562 B3 (post-publication prior art pursuant to Section 3 (2) PatG), DE 10 2023 132 169 B3 (post-publication prior art pursuant to Section 3 (2) PatG) and JP 2010 - 251 019 A each disclose the subject matter of the preamble of claim 1.

[0007] DE 102018200254 A1 describes a safety valve having a receiving groove bounded by two webs. The first web faces away from the receiving groove and has a ramp. This design allows the first web to spring back elastically when the safety valve is pressed into the housing opening or pressed onto the receiving fitting.

[0008] WO 2013121990 A1 describes an explosion-preventing valve consisting of an annular resin housing, 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 and attached to the housing to close a central opening in the explosion-preventing housing. In addition, stop nails are provided, each having a suspension part at the tip that swells in the direction of the outer diameter and is elastically deformable in the diameter direction due to the elasticity of the resin material.

[0009] EP 3739664 A1 describes a safety valve for an electrochemical device, which 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 installed in openings at the bottom of the safety valve. These openings provide a gas passage when a certain pressure and / or temperature inside the device housing is exceeded. The safety valve also includes sealing elements, such as O-ring seals, and a protective top cover that forms a cavity. Furthermore, the safety valve has a pressure equalization zone formed by a gas-permeable diaphragm, which equalizes minor pressure differences between the inside of the device housing and the environment.

[0010] CN 202930452 U describes an explosion-proof valve for the degassing opening of a battery pack.

[0011] US 9669496 B2 describes an explosion-proof valve made of an elastic material such as rubber or resin. It has a cylindrical tube section inserted into a hole. An annular outer flange is integrated at one end of the tube section, engaging with the rim of the hole outside the container. An annular locking projection is integrated at the other end of the tube section, engaging with the rim of the hole inside the container. A diaphragm is integrated inside the tube section, extending axially at one end, which opens and releases pressure when the internal pressure exceeds a predetermined value. Disclosure of the invention

[0012] One problem is that existing seals do not provide reliable and lasting protection against the leakage of coolant from the housing. This coolant is used to regulate the temperature of the cells and must not escape from the housing during normal operation. However, current sealing systems often offer only limited sealing effectiveness, especially when exposed to significant temperature fluctuations or pressure changes. This can lead to the coolant escaping from the housing despite the seal, which can impair cooling performance and potentially damage the battery cells.

[0013] Secondly, in the event of cell overheating, the seals must provide a safe venting path for the hot gases. However, existing sealing systems are often unable to meet these requirements. In particular, the hot gases can damage the sealing elements, impairing their sealing capacity.

[0014] Another problem is that the seals must also allow for a certain degree of tolerance compensation. Since the battery cells and the housing are usually manufactured separately, slight dimensional deviations can occur during the assembly of the cells in the housing. The seals must be able to compensate for these deviations to ensure a durable and reliable seal of the vent openings.

[0015] Furthermore, the seals must be designed to exert minimal pressure on the cell. Excessive pressure could damage the cell housing and consequently the degassing valve, potentially compromising the battery's safety and performance.

[0016] Ultimately, the seals should be simple and inexpensive to manufacture and assemble. However, many existing sealing systems require significant manufacturing and assembly effort, increasing the cost and complexity of battery production.

[0017] The problem described is solved by a high-voltage battery, methods for its manufacture and use, and a motor vehicle according to the independent claims.

[0018] This approach offers the advantage of a sealing effect that is enhanced in both axial and radial directions by the operating pressure of the cooling system. This results in an effective seal even under strong temperature fluctuations or pressure changes.

[0019] Furthermore, the presented solution 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 service life of the seal.

[0020] Furthermore, the presented seal is designed to exert low contact pressure on the battery cell. This protects the cell housing and the degassing valve, thus contributing to the battery's safety and performance.

[0021] The innovative seal can also be made of heat-resistant materials that retain their function even if the cells overheat. This improves battery safety in the event of a defect and ensures that hot gases can safely escape from inside the cell.

[0022] Finally, the presented solution is characterized by its simple and cost-effective manufacturing and assembly. Thanks to the straightforward design and the use of standardized materials, the seals can be efficiently produced and assembled, thus reducing the costs and complexity of battery production.

[0023] Further advantageous embodiments of the invention are specified in the dependent patent claims. Brief description of the drawings Fig. Figure 1 shows a schematic representation of the seal. Fig. 2 shows detail A according to Fig. 1. Fig. 3 shows detail A according to Fig. 1 in an alternative embodiment. Embodiments of the invention

[0024] The invention will now be explained with reference to the illustrations. Fig. Figure 1 shows the principle of a high-voltage battery whose housing (10) is filled with coolant which flows around the battery cell (12) located inside the housing (10) - with the exception of its degassing valve (13).

[0025] To reliably seal the degassing 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 surrounds the degassing 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.

[0026] 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 it under slight 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.

[0027] The seal also features a ring (15) that frames the degassing 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 hot gases during degassing.

[0028] Fig. 2 shows detail A according to Fig. 1. Here it can be seen that the ring (15) opposite the degassing valve (13) is covered by a membrane (18) that protects the cell vent from the environment (salt spray, etc.) but opens under defined conditions. This membrane (18) is integrally formed with the sealing lips (14). The ring (15) also forms a stop (19) for the seal on the side of the cell (12). Since this seal has an open profile outside the ring (15), the second sealing lip (14) has a circumferential locking lug (16) that rests against the inside of the housing (10) and prevents the seal from slipping out in the axial direction.

[0029] Fig. 3 shows 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 several inlet openings (17) on its outer surface for the coolant (11), which open along the ring (15) between the housing (10) and the battery cell (12).

[0030] During the manufacture of the high-voltage battery, the cell (12) is inserted into the housing (10). The seal is inserted axially towards the cell (12) with respect to the ring (15) until it reaches the stop (19) in the vent opening, while the ring (15) supports the sealing lips (14) radially inwards and their spring force compensates for any tolerances – for example, regarding the diameter of the degassing opening.

[0031] After inserting the cell (12) and the seal, the housing (10) is filled with the coolant (11). The sealing lips (14), by their spring force, prevent the coolant (11) from flowing out through the vent opening. Before inserting the seal, the sealing lips (14) are vulcanized to the ring (15).

[0032] During operation, the coolant (11) is pressurized, exerting a pressure force (21) on the sealing lips (14) in the same direction as the spring force. If the battery cell (12) overheats, its degassing valve (13) opens and the diaphragm (18) ruptures, allowing gas escaping from the housing (10) to pass through its degassing opening. The seal prevents the coolant (11) from entering the gas, and the ring (15) protects the sealing lips (14) from the escaping gas. Reference symbol list 10 cases 11 Coolant 12 battery cells 13 Degassing valve 14 Sealing lip 15 rings 16 Rastnase 17 Entrance opening 18 Membran 19 attacks 20 direction 21 Compressive force A Detail

Claims

[1] High-voltage battery with the following characteristics: - the high-voltage battery has a housing (10) designed for filling with coolant (11), - the housing (10) contains at least one battery cell (12) with a degassing valve (13) which is arranged inside 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 fitted with a seal, into which the degassing valve (13) opens, - the seal has a first sealing lip (14) that fits snugly against the battery cell (12) and surrounds the degassing valve (13), - the seal has a second sealing lip (14) that fits snugly against the housing (10) and surrounds the degassing opening, - the seal includes a dimensionally stable and heat-resistant ring (15) and - the first and second sealing lips (14) are connected to each other via the ring (15) in such a way that the first sealing lip exerts a spring force directed axially to the battery cell (12) with respect to the ring and the second sealing lip exerts a spring force directed radially outwards, characterized by the following characteristics: - the first and second sealing lips (14) are connected to each other on both sides to form a hose and - the seal has several inlet openings (17) on the outside for the coolant (11), which open along the ring (15) between the housing (10) and the battery cell (12). [2] High-voltage battery according to claim 1, characterized by the following characteristics: - the seal has an open profile outside the ring (15) and - the second sealing lip (14) has a locking lug (16) which rests against the inside of the housing (10). [3] High-voltage battery according to one of claims 1 or 2, characterized by the following characteristics: - the ring (15) is spanned opposite the degassing valve (13) by a diaphragm (18) and - the membrane (18) is integrally formed with the sealing lips (14). [4] High-voltage battery according to claim 3, characterized by the following characteristics: - 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. [5] Production of a high-voltage battery according to claim 4, characterized by the following characteristics: - the cell (12) is inserted into the housing (10), - the seal is inserted axially towards the cell (12) with respect to the ring (15) into the vent opening until it reaches the stop (19), 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 by their spring force. [6] Production according to claim 5, characterized by the following characteristic: - Before the seal is inserted, the sealing lips (14) are joined to the ring by vulcanization. [7] Use of a high-voltage battery according to claim 3 or 4, characterized by the following characteristics: - the coolant (11) is pressurized so that it reinforces the seal by exerting a pressure force (21) on the sealing lips (14) in the same direction as the spring force, and - if the battery cell (12) overheats, its degassing valve (13) opens and the diaphragm (18) bursts, so that escaping gas from the housing (10) escapes through its degassing 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. [8] Motor vehicle with a high-voltage battery according to any one of claims 1 to 4.

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