Battery system, method for manufacturing a battery system and motor vehicle

Abstract

The invention relates to a battery system (1), in particular for electric vehicles or hybrid vehicles, comprising a cell assembly (2) of several battery cells (3) with cell vents (4) and a base plate (5) supporting the battery cells (3) with degassing openings (6). The invention further relates to a method for manufacturing such a battery system (1) and to a motor vehicle with such a battery system (1). The battery system (1) is characterized in that a cell vent protection element (8) is provided which engages in the degassing openings (6) of the base plate (5), wherein the cell vent protection element (8) is connected to the base plate (5) by means of a first sealing connection (9), and wherein the cell vent protection element (8) is connected to the cell assembly (2) by means of at least one second sealing connection (10).

Description

The invention relates to a battery system, particularly for electric or hybrid vehicles, comprising a cell assembly of several battery cells with cell vents and a base plate supporting the battery cells with degassing openings. The invention further relates to a method for manufacturing such a battery system and to a motor vehicle with such a battery system. Battery systems for electric vehicles, or high-voltage batteries for electric vehicles, are well-known from the prior art and comprise a large number of individual battery cells, especially lithium-ion battery cells. Since an electric vehicle requires the highest possible energy density in its battery systems, particularly efficient grouping and cooling of the battery cells is necessary. Various solutions are known for this. From DE 10 2010 052 506 B4, a battery pack is known which comprises several flat cells arranged in the interior of a housing with spaces formed between them. The disclosure mainly deals with temperature control of the battery pack by means of a gas stream introduced into and discharged from the housing. Accordingly, the flat cells are fastened in the housing by means of gas-carrying retaining strips through which gas is introduced into the interior of the housing. DE 10 2013 002 877 B4 discloses a battery comprising a cell stack of several planar cells and several planar support elements. The cells and support elements are arranged alternately in a stacking direction, and each cell is bonded to the adjacent support element. At least some of the support elements have fastening elements that are attached to a structural element. DE 10 2009 039 394 A1 describes a cooling plate for a galvanic cell, comprising a cell area for coupling with the galvanic cell, a connection area for mechanical and thermal connection with a cooling plate, and a folded area. The folded area is located between the cell area and the connection area and has a flexible fold that allows decoupling between the mechanical connection and the thermal contact. A well-known challenge in the densely packed battery systems for electric vehicles is that internal local overheating in a battery cell, for example, due to a short circuit caused by an internal cell defect, can lead to thermal runaway. This, in turn, can cause overheating and short circuits, and thus thermal runaway in neighboring cells. This chain reaction-like spread to adjacent battery cells, also known as thermal propagation, must be avoided, as it can lead to a fire in the entire high-voltage battery or battery system, posing a significant safety risk to the occupants of the electric vehicle. To prevent a fire and / or explosion of a battery cell in the event of a thermal runaway, it is known to provide a predetermined rupture point, also known as a cell vent, in the cell casing of a battery cell. This vent is designed to rupture when a predetermined limit pressure inside the cell casing is exceeded, allowing a gas and / or flame jet to escape from the interior of the cell casing. It is known that the individual cell vents of the battery cells are connected to a common degassing channel to remove gases from the cell vents with minimal impact on vehicle occupants. However, a problem with this system is that hot gases from one battery cell may come into contact with the cell vents of other battery cells and thus damage them as well. Another problem is the ingress of moisture into the area of ​​the battery cell vents, as the battery systems are primarily located in the underbody of the corresponding vehicles. Moisture in this area can lead to corrosion and, in particular, damage to the cell vents, which in turn can create safety risks. The invention is therefore based on the objective of creating a battery system of the type mentioned above with improved protection of the cell vents from hot gases of neighboring cells while simultaneously improving sealing against external moisture. The problem is solved by a battery system, a manufacturing process for a battery system, and a motor vehicle with the features of the independent claims. Advantageous or preferred embodiments are each the subject of a corresponding dependent claim. A battery system is proposed, comprising a cell assembly of several battery cells with cell vents and a base plate supporting the battery cells. The base plate has degassing openings, and the degassing openings and the battery cells are arranged such that the cell vent of each battery cell is positioned opposite a degassing opening. The battery system is characterized by the inclusion of a cell vent protection element that engages in the degassing openings of the base plate. The cell vent protection element is connected to the base plate by means of a first sealing connection, and the cell vent protection element is connected to the cell assembly by means of at least one second sealing connection. The cell vent protection element protects the cell vent area and simultaneously enables controlled degassing in the event of thermal runaway in a battery cell. The specific arrangement of the cell vent protection element within the degassing openings of the base plate ensures a defined path for the escaping gas in the event of a fault. This prevents hot gases and particles from reaching neighboring cells and thereby triggering thermal propagation, i.e., the runaway of further cells. For example, a separate cell vent protection element can be provided for each degassing port, allowing for individual adaptation to each battery cell. Alternatively, a single, continuous cell vent protection element can be used for multiple degassing ports, covering several or all of them as a single, continuous insert. This design simplifies assembly and reduces the number of components required. Another key advantage of the battery system according to the invention lies in the improved sealing against the ingress of moisture. The first sealing connection between the cell vent protection element and the base plate reliably prevents water or moisture from penetrating the high-voltage area of ​​the battery system through the degassing openings. This sealing is of great importance in motor vehicles, since, as already described, the battery systems are frequently mounted in the vehicle's underbody and are exposed to splashing water, slush, and other environmental influences. In contrast to conventional solutions, where additional sealing films or materials must be applied under the battery system, the concept according to the invention integrates the sealing function directly into the cell vent protection element. The second sealing connection between the cell vent protection element and the cell assembly creates an additional barrier against moisture migration within the battery system. This double seal ensures long-term protection of the high-voltage area against moisture ingress, thus significantly increasing the operational reliability and service life of the battery system. Under real-world operating conditions in motor vehicles, where temperature fluctuations and vibrations can lead to material fatigue, the double sealing connection offers greater reliability than single sealing elements. The tight connection between the base plate, cell vent protection element, and cell assembly, created by the sealing joints, significantly increases the overall system's mechanical stability. This stability is achieved through a sandwich construction, where the base plate and cell assembly are structurally connected by the cell vent protection element. This homogenizes the force distribution within the battery system, which is particularly advantageous under dynamic loads, such as those encountered in motor vehicles. The increased overall stiffness of the battery system reduces relative movement between components, thereby extending the battery system's service life. In this context, it is advantageous if the cell vent protection element has a completely waterproof surface. The completely waterproof surface of the cell vent protection element significantly improves the protection of the battery system against moisture ingress. A "completely waterproof surface" is defined as a surface finish that forms a barrier against liquids across the entire surface of the cell vent protection element, without any breaks or permeable areas. This property is particularly advantageous because it allows the cellular vent protection element to offer moisture protection not only in the area of ​​the sealing connections, but throughout its entire structure. This creates an additional layer of safety that maintains the integrity of the moisture protection even in the event of local damage or partial aging of the sealing connections. The cell vent protection element can preferably be made of water-impermeable materials such as plastic, particularly reinforced plastic. Alternatively, a design made of metal or a composite material is also conceivable. When selecting the material, particular attention must be paid to the requirements for thermal resistance and failure behavior at elevated temperatures. In the event of thermal runaway in an adjacent battery cell, the material should be sufficiently resistant on the one hand, and on the other hand, capable of controlled failure in defined areas to allow for controlled degassing. Reinforced plastics offer a good compromise between strength, temperature resistance, weight, and cost. The waterproof design of the cell vent protection element ensures that the degassing openings of the base plate remain permanently sealed, except in the event of a thermal emergency. This reliably prevents moisture from entering the high-voltage section of the battery system, even under extreme environmental conditions such as heavy rain, driving through puddles, or condensation due to temperature fluctuations. This significantly extends the service life of electrical components and considerably reduces the likelihood of corrosion on metallic connections. Despite its waterproof properties, the cell vent protection element is specifically designed to yield or open in a controlled manner when defined temperature or pressure values ​​are reached in predetermined areas, thus allowing degassing of the cell vent, for example into a degassing channel. It is also advantageous if the first sealing connection is formed all the way around. A continuous, continuous sealing connection between the vent protection element and the base plate ensures a complete seal along the entire perimeter of the degassing openings. "Continuous" means that the sealing connection runs in a closed contour around the degassing opening, without any breaks through which moisture could penetrate. When the vent protection element is designed as a continuous insert for several or all degassing openings, the circumferential sealing connection can alternatively run around all or part of the degassing openings. In this case, not each individual degassing opening is sealed separately, but rather a common circumferential sealing connection is formed around several or all of them. This simplifies the manufacturing process and reduces the amount of sealing material required. This circumferential arrangement of the first sealing connection is particularly effective in preventing moisture from penetrating between the base plate and the vent protection element. Unlike point seals or partial circumferential seals, which can create potential leakage paths, the fully circumferential sealing connection creates a continuous barrier against moisture ingress. The circumferential sealing connection can preferably be designed as a linear or surface seal. In the case of a linear seal, for example, a continuous sealing bead of elastic material such as silicone is applied around the degassing port or a group of degassing ports, while in the case of a surface seal, the entire contact surface between the cell vent protection element and the base plate is coated with a sealing material. The choice of specific design can be made depending on the geometry of the battery system and the expected environmental conditions. Another advantage of the continuous sealing connection lies in the improved force distribution between the base plate and the cell vent protection element. The continuous connection line ensures a uniform transmission of mechanical forces and prevents local stress concentrations that could occur with point connections. This increases the mechanical stability of the overall structure and reduces the risk of the sealing connection detaching or being damaged by vibrations or shock loads, such as those that can occur during driving. In the event of thermal runaway in a battery cell, the circumferential sealing connection ensures that escaping gases and particles are directed only through the designated areas of the cell vent protection element and cannot escape laterally between the cell vent protection element and the base plate. This improves the predictability of the gas flow in the event of a fault and thus increases the safety of the overall system. It is also extremely advantageous if at least one of the sealing connections is designed as an adhesive connection, in particular by means of double-sided adhesive tape or silicone, and / or as a lamellar seal. An adhesive bond is a material-bonded connection where an adhesive creates a permanent bond between two surfaces. Double-sided adhesive tape consists of a backing material coated with adhesive on both sides and is particularly suitable for simple and quick assembly processes. Silicone, on the other hand, is an elastic sealant that hardens after application, creating a flexible yet durable bond. The use of double-sided adhesive tape enables a precise, uniform bond with a defined thickness, which is advantageous for maintaining tight tolerances between the components of the battery system. It is also easy to handle during manufacturing and ensures consistent bond quality. Silicone adhesives, on the other hand, can compensate for unevenness and tolerances between the surfaces to be joined and remain elastic even after curing, which can absorb stresses caused by differences in thermal expansion. As an alternative or supplement to adhesive bonding, a lamellar gasket can be used. A lamellar gasket consists of flexible, parallel sealing lips that create a seal between two components through elastic deformation. Unlike a material-bonded adhesive bond, this is a force-fit seal that works through mechanical pressure. The advantage of a lamellar seal lies particularly in its reusability and ease of disassembly. During maintenance or when replacing individual battery cells, components with lamellar seals can be disassembled and then reassembled without compromising the sealing function. This is especially important for the secondary sealing connection between the cell vent protection element and the cell stack, where individual cells may need to be replaced. The lamellar seal can preferably be made of an elastomeric material such as EPDM, NBR, or silicone, which retains its elastic properties even after prolonged use and under varying temperature conditions. The number, thickness, and geometry of the sealing lamellae can be varied depending on the required contact pressure and available installation space. A combination of both sealing types is also possible and can combine their respective advantages. For example, the first sealing connection between the cell vent protection element and the base plate can be designed as an adhesive bond with silicone to ensure a permanently watertight connection, while the second sealing connection to the cell stack is designed as a lamellar seal to allow for easier assembly and disassembly. It is particularly advantageous if the cell vent protection element has at least one recess that engages in the degassing openings of the base plate. The formation of recesses on the cell vent protection element, which engage with the degassing openings of the base plate, significantly improves the mechanical connection between these components. A "recess" in this context refers to a concave shape of the cell vent protection element, whose geometry is adapted to and engages with the degassing opening of the base plate. This design feature creates a positive-locking connection between the cell vent protection element and the base plate, thus precisely defining the positioning of the components relative to each other. The recesses can have different shapes, for example, cylindrical, conical, and / or trough-shaped, depending on the geometry of the degassing openings in the base plate. A key advantage of this positive-locking connection is its increased resistance to shear forces that can occur during battery system operation. While a purely adhesive bond without positive locking could fail under strong lateral forces, the combination of a sealing connection and positive locking offers significantly higher mechanical stability. The recesses also create a defined receiving space for the material escaping when a cell vent opens. In the event of thermal runaway in a battery cell, hot gases and potentially material particles escape from the cell vent. The recesses of the cell vent protection element serve as an equalization volume for the escaping gas flow, thus reducing the risk of blockage formation in front of the cell vent. This is particularly important to ensure immediate pressure relief within the cell casing of the thermally runaway battery cell and to reduce the risk of the cell casing opening at a location other than the cell vent. The recesses can preferably be dimensioned such that there is a clear distance between the cell vent of the battery cell and the bottom surface of the recess. This distance should be greater than the maximum expansion movement of the cell vent when opening, in order to prevent mechanical obstruction of the opening process. Experience shows that a distance between 4 mm and 6 mm can be suitable for this purpose. Another advantage of the recesses lies in the improved ease of assembly of the battery system. During assembly, the recesses act as guides, facilitating the correct positioning of the cell vent protection element on the base plate. This reduces assembly errors and shortens manufacturing time. It is advantageous if the cell vent protection element is designed in such a way that it fails in the event of thermal runaway of a battery cell, when a predetermined boundary condition is exceeded, in particular a temperature and / or pressure in a predetermined range. As previously described, thermal runaway refers to the uncontrolled heating of a battery cell, which can be triggered by internal short circuits or other defects and leads to a self-reinforcing exothermic reaction. This results in high temperatures and pressures inside the battery cell, which can lead to the release of gases and potentially flammable materials. The specified "boundary conditions" refer to the parameters under which the cell vent protection element is designed to fail. These parameters, particularly temperature and / or pressure, are chosen so that failure only occurs when thermal runaway actually takes place, but before an uncontrolled bursting of the battery cell can occur. Under normal conditions, the cell vent protection element ensures a reliable seal against moisture and the mechanical stability of the overall system. However, in the event of a fault, such as a battery cell experiencing thermal runaway, it creates a defined weak point through which escaping gases and heat can be dissipated in a controlled manner. The cell vent protection element can, for example, feature local material reductions dimensioned to melt or mechanically fail upon reaching a specific temperature or pressure. Alternatively, defined predetermined breaking points can be incorporated into the cell vent protection element, which break when predefined boundary conditions are exceeded, allowing a controlled release of gases. The failure of the cell vent protection element in predetermined areas is specifically designed to occur in close coordination with the opening behavior of the battery cell's cell vent. As soon as the cell vent opens and hot gases are released, the controlled failure of the cell vent protection element ensures that these gases can be vented in a controlled manner, for example into a degassing channel, without endangering neighboring battery cells. Of particular importance is that the cell vent protection element maintains its protective function against thermally perforated neighboring cells despite local failure in the predetermined areas. It acts as a shield, keeping out thermal energy and escaping particles from neighboring cells. This effectively prevents a chain reaction-like spread of thermal propagation to adjacent cells. The invention further relates to a manufacturing method for a battery system, in particular as previously described. In the method according to the invention, a base plate with degassing openings and a cell assembly consisting of several battery cells with cell vents are first provided. A cell vent protection element is arranged in the degassing openings of the base plate, whereby a first sealing connection is established between the cell vent protection element and the base plate. The cell assembly is then arranged such that the cell vent of each battery cell is positioned opposite a degassing opening, wherein at least a second sealing connection is established between the cell vent protection element and the cell assembly. This manufacturing process produces a battery system that exhibits the previously described advantageous properties. The step-by-step assembly ensures, in particular, the precise positioning of the cell vent protection element, thereby guaranteeing a reliable seal against the ingress of moisture into the high-voltage area of ​​the battery system. The creation of the initial sealing connection between the cell vent protection element and the base plate establishes a watertight barrier that prevents moisture from penetrating through the degassing openings. This is particularly relevant for electric vehicles, whose battery systems are often mounted in the vehicle's underbody and exposed to environmental influences such as splashing water. The second sealing connection between the cell vent protection element and the cell assembly ensures that no moisture migration can occur in this area either. Furthermore, the double sealing connection significantly contributes to the mechanical stability of the overall system. The sandwich-like connection of the base plate, cell vent protection element, and cell assembly achieves increased rigidity, minimizes relative movement between the components, and extends the system's service life. The correct positioning of the cell vents relative to the degassing ports is crucial for the system's safety function. In the event of thermal runaway in a battery cell, this arrangement enables controlled degassing via the cell vent protection element. The cell vent protection element acts as a shield, effectively preventing thermal propagation. Assembling these components in the described sequence ensures that the resulting battery system has all the desired properties regarding tightness, mechanical stability and safety in the event of thermal runaway. For the process it is advantageous if at least one of the sealing connections is produced as an adhesive connection, in particular by means of double-sided adhesive tape or silicone and / or as a lamellar seal. When using double-sided adhesive tape for bonding, the tape can preferably be applied to the relevant components before assembly. The double-sided tape typically has a protective film on both sides, which is removed immediately before the bonding process. This allows for clean and controlled assembly, as the adhesive is only activated at the desired moment. Precisely cut pieces of tape ensure reproducible bonding surfaces of consistent thickness, resulting in a consistently high-quality bond. When using silicone as an adhesive, the application can be carried out, for example, by automated dispensing systems. These enable precise dosing and positioning of the silicone along defined paths or surfaces. In particular, self-leveling silicones can be used, as they can compensate for minor irregularities in the surfaces to be bonded. The production of the sealing connection as a lamellar seal requires, in particular, the integration of prefabricated sealing profiles, which preferably correspond to appropriate receiving geometries on the vent protection element or the base plate. The lamellar seal can preferably be fixed in a groove or a similar guide structure, which ensures defined positioning during assembly. The sealing function is created by the elastic behavior of the sealing lamellae when the components are joined by contact pressure, whereby the lamellae are elastically deformed and adapt to the mating surface. One advantage of lamellar seals over adhesive bonds is their immediate functionality after installation, as no curing time is required. This can be particularly beneficial in timed production lines, where waiting times would disrupt the production flow. The different sealing connection types can be used depending on the specific requirements at various points in the battery system. For example, the first sealing connection between the cell vent protection element and the base plate can be implemented as a permanent silicone bond, while the second sealing connection to the cell assembly is realized as a lamellar seal to facilitate any necessary cell replacement. The invention further relates to a motor vehicle with a battery system, wherein the battery system is configured according to the preceding description. The described features can be implemented individually or in any combination. In modern electric and hybrid vehicles, battery systems represent a central component that is exposed to high mechanical, thermal, and climatic stresses. The increased water resistance of the battery system according to the invention, achieved through the double sealing connection between the cell vent protection element, base plate, and cell assembly, is of particular importance in the automotive sector, as battery systems are frequently installed in the vehicle's underbody and are thus exposed to increased environmental influences such as splashing water, slush, and road salt. The battery system in the vehicle can preferably be arranged such that the base plate is oriented towards the vehicle underbody. In this installation position, the base plate, together with the cell vent protection element, forms an effective barrier against moisture that could penetrate the battery system from below. The degassing openings and the cell vent protection element can be oriented so that, in the event of thermal runaway in a battery cell, the gases are vented downwards out of the vehicle, which is advantageous for safety reasons. The increased mechanical stability of the battery system, achieved through its sandwich-like construction, counteracts the vibrations and shocks encountered in motor vehicles. These vibrations and shocks arise both from driving itself and from the condition of the road surface and represent a significant stress on vehicle battery systems. The positive-locking connection of the cell vent protection element to the base plate, facilitated by interlocking recesses, further enhances resistance to these dynamic loads. A further advantage for use in motor vehicles arises from the improved safety in the event of thermal runaway in a battery cell. The targeted design of the cell vent protection element to fail in defined areas under specified boundary conditions while simultaneously protecting neighboring cells is of considerable importance for the overall safety of the vehicle. Preventing thermal propagation significantly reduces the risk of a battery fire and thus increases the safety of the vehicle occupants. Further advantages of the invention are described in the following exemplary embodiments. The figures show, schematically: Fig. 1 an exploded view of a battery system according to the invention, Fig. 2 an enlarged exploded view of the battery system in the area of ​​the cell vent protection element, and Fig. 3 a side view of the battery system. In the following description of the figures, the same reference symbols are used for features that are identical and / or at least comparable in the various figures. The individual features, their design, and / or mode of action are usually only explained in detail upon their first mention. If individual features are not explained again in detail, their design and / or mode of action corresponds to the design and mode of action of the already described features with the same or identical effect. Fig. 1 shows an exploded view of a battery system 1 according to the invention in perspective. The battery system 1 comprises a cell assembly 2 consisting of several planar, parallel-arranged battery cells 3. The battery cells 3 are arranged in a regular pattern within the cell assembly 2 and can be, for example, lithium-ion cells, in particular pouch cells. A cell vent 4 is formed on the underside of each battery cell 3, serving as a predetermined breaking point or degassing device. These cell vents 4 are designed to open when a predetermined limit pressure inside the respective battery cell 3 is exceeded, in order to allow controlled degassing. Below the cell assembly 2 is the flat base plate 5, which supports the cell assembly 2. The base plate 5 has several degassing openings 6, which are designed as essentially rectangular openings. These degassing openings 6 penetrate the base plate 5 completely. The arrangement of the degassing openings 6 in the base plate 5 corresponds precisely to the arrangement of the cell vents 4 on the battery cells 3, so that when the battery system 1 is assembled, each cell vent 4 is aligned opposite a degassing opening 6. The base plate 5 can also perform a cooling function for the battery cells 3. For this purpose, the base plate 5 can, for example, include cooling channels. Below the base plate 5, a degassing channel 7 is indicated, into which the degassing openings 6 lead. The degassing channel 7 serves to remove gases that escape through the corresponding cell vent 4 and the associated degassing opening 6 in the event of thermal runaway in one of the battery cells 3. Guiding the gases through the degassing channel 7 allows for controlled discharge to the outside, thereby reducing the risk of damage to adjacent battery cells 3. The cell vent protection element 8 is arranged between the cell assembly 2 and the base plate 5. The cell vent protection element 8 is designed as a planar element and has several recesses 11 in its central area, the arrangement of which corresponds to the degassing openings 6 of the base plate 5. These recesses 11 are designed so that, when the battery system 1 is assembled, they engage with the degassing openings 6 of the base plate 5, thereby creating a positive connection. The recesses 11 also provide a defined space for escaping gases and materials in the event of thermal runaway in a battery cell 3. Predetermined areas 12 are formed in the recesses 11 of the cell vent protection element 8, enabling controlled failure upon exceeding a predefined boundary condition, in particular a critical temperature and / or a critical pressure. These predetermined areas 12 can, for example, be designed as local material reductions or defined predetermined breaking lines, which ensure the watertightness of the cell vent protection element 8 under normal conditions, but which, in the event of a failure, selectively break open or melt. The sealing connections between the cell vent protection element 8 and the base plate 5 on the one hand, and between the cell vent protection element 8 and the cell assembly 2 on the other, which are not shown here for clarity, are explained in detail in the following Fig. 2. In the assembled state, these sealing connections function as a watertight barrier and contribute to the mechanical stabilization of the entire battery system 1. Fig. 2 shows an enlarged exploded view of a section of the battery system 1 in the area of ​​the cell vent protection element 8. This detailed view particularly illustrates the structure and arrangement of the sealing connections, which are not shown in Fig. 1. In this embodiment, the cell vent protection element 8 is designed as a planar element with a continuously waterproof surface and, as before, has recesses 11 that engage in the degassing openings 6 of the base plate 5. Predetermined areas 12 are located in the recesses 11, which, in the event of thermal runaway of a battery cell 3 when a defined temperature or pressure is exceeded, are designed to fail in a controlled manner in order to allow controlled degassing while simultaneously protecting adjacent cells from thermal damage. A first sealing connection 9 is arranged between the cell vent protection element 8 and the base plate 5. This is preferably formed around the degassing openings 6 and forms a watertight barrier between the cell vent protection element 8 and the base plate 5. The first sealing connection 9 can, for example, be designed as an adhesive bond or as a lamellar seal and reliably prevents the ingress of moisture into the battery system 1. A second sealing connection 10 is arranged between the cell assembly 2 and the cell vent protection element 8. This second sealing connection 10 extends, for example, across the entire area between the cell vent protection element 8 and the cell assembly 2 and can be designed as an adhesive connection, for example using double-sided adhesive tape or silicone, or as a lamellar seal. The illustrated sandwich construction consisting of cell assembly 2, cell vent protection element 8 and base plate 5, which is held together by the first sealing connection 9 and the second sealing connection 10, contributes significantly to the increased mechanical stability of the entire battery system 1 and at the same time ensures a reliable seal against the ingress of moisture. Fig. 3 shows a side view of the battery system 1 in its assembled state. The illustration particularly demonstrates the layered arrangement of the components and the positioning of the sealing connections 9, 10. The cell assembly 2, consisting of several battery cells 3 arranged side by side, can be seen in the upper part of the illustration. The battery cells 3 are arranged at regular intervals and form a closed unit. Cell vents 4 are positioned on the underside of each battery cell 3, enabling controlled degassing in the event of thermal runaway of the respective battery cell 3. Several secondary sealing connections 10 are arranged between the cell assembly 2 and the cell vent protection element 8 located below it. These secondary sealing connections 10 extend between the battery cells 3 and the cell vent protection element 8. In particular, two secondary sealing connections 10 can be provided for each battery cell 3. In this embodiment, the cell vent protection element 8 is designed as an insert in the base plate 5. A recess 11 is provided for each cell vent 4 of the battery cells 3, which engages in the degassing openings 6 of the base plate 5. Predetermined areas 12 are arranged in these recesses 11, which, for example, fail in a controlled manner when certain temperature or pressure values ​​are exceeded, thereby enabling controlled degassing. The first sealing connection 9 is arranged between the cell vent protection element 8 and the base plate 5. This connection is formed around the degassing openings 6 of the base plate 5 and provides a watertight barrier between these components. The first sealing connection 9 can also be designed as an adhesive bond or a lamellar seal. The base plate 5 forms the lower termination of the battery system 1 and serves as a supporting structure for the components arranged above it. The sandwich structure consisting of cell assembly 2, second sealing connection 10, cell vent protection element 8, first sealing connection 9, and base plate 5 ensures high mechanical stability of the entire battery system 1. The side view illustrates how the two sealing connections 9 and 10 contribute to both the watertight seal and the structural connection of the individual components. The continuous seal reliably prevents moisture from penetrating the battery system 1, while at the same time, the recesses 11 and predetermined areas 12 ensure controlled gas release in the event of a fault. REFERENCE MARK LIST 1. Battery system 2. Cell assembly 3. Battery cells 4. Cell vent 5. Base plate 6. Degassing ports 7. Degassing channel 8. Cell vent protection element 9. First sealing connection 10. Second sealing connection 11. Recess 12. Predetermined area

Claims

Battery system (1) comprising a cell assembly (2) of several battery cells (3) with cell vents (4) and a base plate (5) supporting the battery cells (3), wherein the base plate (5) has degassing openings (6), wherein the degassing openings (6) and the battery cells (3) are arranged relative to each other such that the cell vent (4) of each battery cell (3) is positioned opposite a degassing opening (6), characterized in that a cell vent protection element (8) is provided which engages in the degassing openings (6) of the base plate (5), wherein the cell vent protection element (8) is connected to the base plate (5) by means of a first sealing connection (9), and wherein the cell vent protection element (8) is connected to the cell assembly (2) by means of at least one second sealing connection (10). Battery system (1) according to the previous claim, characterized in that the cell vent protection element (8) has a continuously waterproof surface. Battery system (1) according to one of the preceding claims, characterized in that the first sealing connection (9) is formed circumferentially. Battery system (1) according to one of the preceding claims, characterized in that at least one of the sealing connections (9, 10) is designed as an adhesive connection, in particular by means of double-sided adhesive tape or silicone, and / or as a lamellar seal. Battery system (1) according to one of the preceding claims, characterized in that the cell vent protection element (8) has at least one recess which engages in the degassing openings (6) of the base plate (5). Battery system (1) according to one of the preceding claims, characterized in that the cell vent protection element (8) is designed such that it fails in a predetermined area (12) in the event of thermal runaway of a battery cell (3) when a predetermined boundary condition, in particular a temperature and / or a pressure, is exceeded. Method for manufacturing a battery system according to one of the preceding claims, characterized by the following steps: - providing a base plate (5) with degassing openings (6) and a cell assembly (2) of several battery cells (3) with cell vents (4), - arranging a cell vent protection element (8) in the degassing openings (6) of the base plate (5) and establishing a first sealing connection (9) between the cell vent protection element (8) and the base plate (5), - arranging the cell assembly (2) such that the cell vent (4) of each battery cell (3) is positioned opposite a degassing opening (6) and establishing at least one second sealing connection (10) between the cell vent protection element (8) and the cell assembly (2). Method according to the previous claim, characterized in that at least one of the sealing connections (9, 10) is produced as an adhesive connection, in particular by means of double-sided adhesive tape or silicone, and / or as a lamellar seal. Motor vehicle with a battery system (1), characterized in that the battery system (1) is designed according to one of claims 1 to 6.

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