Traction battery of a motor vehicle, method for manufacturing a traction battery, motor vehicle

Abstract

A traction battery (1) for a motor vehicle (100) is proposed, comprising a plurality of battery cells (3), a battery housing (2), and a carrier plate (4), wherein the carrier plate (4) rests flatly on a wall of the battery housing (2) with a base plate (10), wherein the carrier plate (4) has cell vents (5) which are arranged above housing openings (6) of the battery housing (2), wherein the cell vents (5) each have a projection (7) on which one of the battery cells (3) is arranged such that a cell opening (8) of the battery cell (3) is arranged above the cell vent (5), wherein the cell vents (5) each have a seal (9) which is arranged circumferentially around the respective cell opening (8), wherein the projections (7) and / or the seals (9) space the battery cells (3) away from the base plate (10) by an oil space (11).Furthermore, a method for manufacturing a traction battery (1) and a motor vehicle (100) are proposed.

Description

The present invention relates to a traction battery for a motor vehicle comprising a plurality of battery cells, a battery housing, and a carrier plate. The present invention further relates to a method for manufacturing a traction battery for a motor vehicle and to a motor vehicle. Motor vehicles with an electrified powertrain, i.e., electric vehicles or hybrid vehicles, use an electric motor as their traction motor. This electric motor is powered by a traction battery. During operation, high currents generate heat in a motor vehicle. This heat, especially in high-performance vehicles, limits performance and must be dissipated. This applies to the electric motor as well as to the vehicle's power electronics, which convert the high voltage supplied by the traction battery to the required voltage, and to the traction battery itself. The use of coolant has proven to be very efficient. The coolant, for example a cooling oil, flows along the components to be cooled, absorbs heat, and releases it, for example, via a chiller. Essential for safe operation and reliable cooling is that no coolant leaks and that the vehicle component being cooled is properly sealed. Traction batteries in motor vehicles typically use lithium-ion battery cells. In rare cases, for example, after mechanical damage from an accident, a so-called thermal runaway of the traction battery can occur. A typical trigger for thermal runaway is a short circuit in one of the battery cells, caused by mechanical damage. The short circuit generates high currents in the battery cell, leading to high temperatures. This causes flammable gases to be released. If these gases ignite, they generate additional heat, which in turn releases more flammable gases. To ensure that the flammable gases from the traction battery are vented in a controlled manner, preventing ignition and allowing them to cool as effectively as possible on their way out of the battery and into the exterior of the vehicle, the battery cells must be arranged within the traction battery in such a way that a defined path exists for the flammable gases to escape. This requires passageways from the battery cells through the battery housing. These passages typically include so-called cell vents, areas that are normally closed and only allow flammable gases to escape when needed. The area around the cell vents is typically prone to leaks through which coolant can escape. A traction battery according to the preamble of claims 1 and 2 is known from German patent application DE 10 2023 130 905 A1. German patent application US 2013 / 0 059 175 A1 discloses a circumferential, one-piece sealing arrangement of a traction battery that includes all cell vents. German patent application EP 3 965 217 A1 discloses a traction battery with sealed cell vents and a circumferential seal. German patent applications WO 2018 / 023 050 A1 and DE 10 2021 131 908 A1 also disclose traction batteries with sealed cell vents. It is an object of the present invention to provide a traction battery for a motor vehicle, a method for manufacturing a traction battery and a motor vehicle with a traction battery, which do not have the aforementioned disadvantages of the prior art and enable a high degree of sealing and a simple possibility for mounting the traction battery with highly efficient and powerful cooling of the traction battery. This problem is solved by a traction battery according to claim 1. Furthermore, this problem is solved by a traction battery according to claim 2, a method for manufacturing a traction battery according to claim 8, and by a motor vehicle according to claim 9. The traction battery according to the invention is a traction battery for a motor vehicle. It comprises a plurality of battery cells, a battery housing, and a carrier plate. The carrier plate rests flat against a wall of the battery housing with its base plate. The wall is, in particular, a bottom surface of the battery housing. The carrier plate has cell vents arranged such that a cell opening of a battery cell is located above each cell vent, and a housing opening of the battery housing is located below the cell vent. Each cell vent has a projection on which a battery cell is arranged. The projections space the battery cells away from the base plate in such a way that an oil space is created between the battery cells and the base plate. The oil space is designed to be supplied with a coolant, in particular a cooling oil.The coolant is applied to the battery cells, cooling them. Each cell vent has a seal that surrounds the respective cell opening. This effectively seals the oil chamber. Preferably, the seals are injection-molded onto the carrier plate. Alternatively, the seals are provided as CIP (Clean-in-Place) products. The cell vents and / or the housing openings and / or the cell openings are preferably punched. It is conceivable that additional seals are provided between the battery cells. These additional seals could advantageously be designed to seal the oil chamber in such a way that no coolant can penetrate between the battery cells, meaning that the coolant is primarily applied to the underside of the battery cells. Advantageous embodiments and further developments of the invention can be found in the dependent claims and in the description with reference to the drawings. According to the invention, a circumferential sealing arrangement, abutting the wall of the base plate and enclosing all cell vents of the carrier plate, is provided. This advantageously ensures that the battery housing is sealed to the outside. According to an invention for solving the problem stated above, the sealing arrangement is provided in a single piece, U-shaped, and with a further part that closes the U-shape to the surrounding form. This advantageously prevents damage to the sealing arrangement when the carrier plate is inserted into the battery housing. It is conceivable that the further part is injection-molded through at least one bore in the battery housing after the carrier plate has been joined to the battery housing. It is also conceivable that a groove is provided in the carrier plate for this purpose. This advantageously allows the sealing arrangement to be closed as soon as the carrier plate is joined to the battery housing. According to a further provision for solving the initial problem, the sealing assembly is designed to be four-part, with two sealing lines along the joining direction of the carrier plate to the battery housing and two additional sealing lines. It is conceivable that the additional sealing lines are injected through at least one bore in the battery housing after the carrier plate has been joined to the battery housing. It is conceivable that grooves are provided in the carrier plate for this purpose. This further ensures that the sealing assembly is not damaged when the carrier plate is inserted into the battery housing. According to a further preferred embodiment of the present invention, static or dynamic turbulence generators, in particular flow fins, are provided on the base plate in the oil chamber. This advantageously makes it possible to pre-turbulate the coolant as it flows through the oil chamber. The turbulence significantly increases the cooling efficiency. Alternatively or additionally, it is preferably provided that channels for conveying a coolant are provided on the base plate in the oil chamber. This advantageously allows for targeted control of the coolant flow through the oil chamber. For example, it is possible to direct the coolant flow to certain areas of the oil chamber more strongly than others, thus enabling individual adjustment of the cooling. Furthermore, the flow velocity of the coolant can be adjusted by appropriately arranging the channels, for example, by means of constrictions. According to a further preferred embodiment of the present invention, the cell vents are integrally sealed with the carrier plate. For this purpose, the cell vents are provided with predetermined breaking points. These predetermined breaking points can, for example, be shaped features. In other words, the carrier plate is simply continued in the area of ​​the cell vents, but is provided with predetermined breaking points. Should gas be generated and thus the pressure inside the traction battery increase, the carrier plate will break open in the area of ​​the predetermined breaking points, i.e., at the corresponding cell vents. Alternatively, it is preferably provided that the cell vents have a cover. The cover is integrally connected to the respective seal or bonded to the respective seal as a separate element. In particular, the cover is designed as a rubber membrane. The cover allows the cell vent to be opened safely in the event of overpressure. In this case, the cover tears open and allows gases from inside the traction battery to escape to the outside. According to a further preferred embodiment of the present invention, the cell vents and / or the housing openings are covered with a metal foil. The metal foil can, for example, be perforated and advantageously enables electromagnetic shielding of the traction battery to be provided, thus complying with EMC requirements. A further object of the present invention for solving the problem formulated at the outset is a method for manufacturing a traction battery for a motor vehicle, comprising a plurality of battery cells, a battery housing and a carrier plate, wherein the carrier plate with a base plate rests flatly on a wall of the battery housing, wherein the carrier plate has cell vents which are arranged above housing openings of the battery housing, wherein the cell vents each have a projection on which one of the battery cells is arranged such that a cell opening of the battery cell is arranged above the cell vent, wherein the cell vents each have a seal which is arranged circumferentially around the respective cell opening, wherein the projections and / or the seals space the battery cells away from the base plate by an oil space.First, the battery housing is prepared, with a film or strips placed on its wall. Then, the carrier plate containing the battery cells is inserted into the battery housing along a guide path on the film or strips. Afterward, the film or strips are removed. Using the film or strips advantageously ensures that the sealing element is not damaged when the carrier plate is inserted into the battery housing. The sealing element can slide into the battery housing over the film or strips. The film is, for example, a PTFE film. It is conceivable that the film is arranged in a single layer on the wall of the battery housing. However, it is also conceivable that the film is arranged in two layers on the wall of the battery housing. All details, features and advantages previously disclosed in connection with the traction battery according to the invention also relate to the method according to the invention. Another object of the present invention for solving the problem formulated at the outset is a motor vehicle comprising a traction battery according to the invention. All details, features and advantages previously disclosed in connection with the traction battery according to the invention also relate to the motor vehicle according to the invention. Further details, features, and advantages of the invention will become apparent from the drawings and from the following description of preferred embodiments with reference to the drawings. The drawings merely illustrate exemplary embodiments of the invention, which do not limit the inventive concept. Fig. 1 schematically illustrates a traction battery according to an exemplary embodiment of the present invention. Figs. 2(a) and (b) schematically illustrate a part of a motor vehicle according to an exemplary embodiment of the present invention. Fig. 3 schematically illustrates a traction battery according to an exemplary embodiment of the present invention. Figs. 4(a) to (c) schematically illustrate a part of a method for manufacturing a traction battery according to an exemplary embodiment of the present invention.Figures 5(a) to (c) schematically illustrate a traction battery according to different exemplary embodiments of the present invention. Figure 6(a) schematically illustrates a sealing arrangement. Figures 6(a) to (c) schematically illustrate parts of a traction battery according to different exemplary embodiments of the present invention. Figure 7 illustrates a motor vehicle with a traction battery according to an exemplary embodiment of the present invention. Fig. 1 schematically illustrates a traction battery 1 according to an exemplary embodiment of the present invention. The traction battery 1 is a traction battery 1 of a motor vehicle 100 (see Fig. 7). The traction battery 1 has a support plate 4 which is arranged on a wall, here on the underside, of a battery housing 2. The carrier plate 4 carries battery cells 3 of the traction battery 1. The battery cells 3 lie on projections 7 (see also Fig. 2 (a) and (b), Fig. 3 and Fig. 5 (a) to (c)). The projections 7 space the battery cells 3 away from a base plate 10 of the carrier plate 4, so that an oil space 11 is created between the base plate 10 and the battery cells 3. During operation of the traction battery 1, a coolant flows through the oil space 11, which dissipates heat from the battery cells 3. The carrier plate 4 has a cell vent 5 for each battery cell 3. The cell vent 5 is enclosed by the projection 7. A cell opening 8 is provided above the cell vent 5. A housing opening 6 is provided in the battery housing 2 below the cell vent 5. If a pressure increase occurs inside the battery cell 3, the excess pressure can be released to the outside in a controlled manner through the cell opening 8, the cell vent 5, and the housing opening 6. A seal 9 is provided around the cell vent 5. The seal 9 is, for example, injection-molded. It seals the oil chamber 11 so that no coolant enters the cell vent 5 and there is a risk that the coolant could enter the interior of the battery cell 3 through the cell opening 8 or escape to the outside through the housing opening 6. Figures 2(a) and (b) show views of the carrier plate 4. The cell vents 5, surrounded by the projections 7, are clearly visible. In the embodiment shown in Figure 2(a), turbulence generators 13 are provided on the carrier plate 4. As the coolant flows through the oil chamber 11, the turbulence generators 13 create turbulence in the coolant, thus improving cooling efficiency. Figure 2(b) shows channels 14 on the carrier plate 4 through which the coolant is guided. This allows the coolant to be directed precisely to positions in the oil chamber 11 where cooling is required. It is conceivable that the channels 14 of Figure 2(b) could be combined with the turbulence generators 13 of Figure 2(a). Figures 5(a) to (c) show different embodiments of the cell vent 5 and the area around the housing opening 6. In Figure 5(a), the cell vent 5 is integrally connected to the carrier plate 4. The function of the cell vent 5 is ensured by the fact that the cell vent 5 itself is designed as a predetermined breaking point. For this purpose, the carrier plate 4 is significantly thinned in the area of ​​the cell vent 5. Fig. 5(b) shows a cell vent 5 which has a cover 15. The cover 15 is designed as a membrane which ruptures under overpressure. The cover 15 is integrally connected to the seal 9. It is also conceivable that the cover 15 is bonded to the seal 9. Fig. 5(c) shows an open cell vent 5. No closure of the cell vent 5 is provided here. The cell vent 5 simply lies as an opening above the housing opening 6. Figure 5(c) shows an example of a metal foil 16. The metal foil 16 closes the housing opening 6 and, analogous to Figure 5(c), can also be provided in the embodiments shown in Figures (a) and 5(b). The metal foil 16 provides electromagnetic shielding for the traction battery 1. Figure 1 shows a sealing arrangement 12. The sealing arrangement 12 seals the interior of the battery housing 2 from the outside. A more detailed, but schematic, representation is shown in Figure 6. Fig. 6 (a) shows a sealing arrangement 12, which is provided in one piece. The sealing arrangement 12 surrounds all cell vents 5 (not shown in Fig. 6). The embodiment of Fig. 6(b) differs from the embodiment of Fig. 6(a) in that the sealing arrangement 12 is provided with a one-piece U-shape 12.1. The carrier plate 4 is inserted into the battery housing 2 with the open side of the U-shape 12.1 leading (i.e., to the left in this case). Once the carrier plate 4 is positioned in the battery housing 2, a further part 12.2 of the sealing arrangement 12 is injected, in which a sealant is injected through at least one bore 20 of the battery housing 2 into a groove 21 of the carrier plate 4 (see Fig. 3). The embodiment shown in Fig. 6(c) provides that two sealing lines 12.3 are first applied, extending along the joining direction F, i.e., along the direction in which the carrier plate 4 is inserted into the battery housing 2. After the carrier plate 4 has been inserted into the battery housing 2, further sealing lines 12.4 are injected through bores 20 in the battery housing 3 into grooves 21 in the carrier plate 4, analogous to the illustration in Fig. 3. To prevent damage to the sealing assembly 12 when the carrier plate 4 is inserted into the battery housing 2, a film 17 (Fig. 4 (a), (b)) is placed on the wall of the battery housing 2 before insertion. The film can be a PTFE film. In Fig. 4(a), the film 17 is folded, i.e., placed in two layers, on the wall. When the carrier plate 4 is inserted into the battery housing 2 over the film 17, the carrier plate 4 can slide over the film 17 or the upper layer of the film 17 can be displaced along the joining direction F. A simpler arrangement is shown in Fig. 4(b). Here, the film 17 is provided in a single layer. The carrier plate 4 slides over the film 17 when inserted. Fig. 4(c) shows strips 18, which are also arranged on the wall of the battery housing 2 and over which the carrier plate 4 is inserted. This embodiment is particularly suitable when the sealing arrangement 12 is produced by arranging two sealing lines 12.3 on the carrier plate 4 before insertion and injecting two further sealing lines 12.3 after insertion (see Fig. 6(c)). The sealing lines 12.3 can slide into position over the strips 18. After inserting the carrier plate 4, the foil 17 or the strips 18 are pulled out and removed. In particular, it is intended that the foil 17 or the strips 18 can be reused multiple times. Reference symbol list 1 Traction battery 2 Battery housing 3 Battery cell 4 Carrier plate 5 Cell vent 6 Housing opening 7 Projection 8 Cell opening 9 Seal 10 Base plate 11 Oil chamber 12 Sealing arrangement 12.1 U-shape 12.2 Further part 12.3 Sealing line 12.4 Further sealing line 13 Turbulence generator 14 Channel 15 Cover 16 Metal foil 17 Foil 18 Strips 19 Further seal 20 Bore 21 Groove 100 Motor vehicle

Claims

Traction battery (1) of a motor vehicle (100), comprising a plurality of battery cells (3), a battery housing (2) and a carrier plate (4), wherein the carrier plate (4) rests flatly on a wall of the battery housing (2) with a base plate (10), wherein the carrier plate (4) has cell vents (5) which are arranged above housing openings (6) of the battery housing (2), wherein the cell vents (5) each have a projection (7) on which one of the battery cells (3) is arranged such that a cell opening (8) of the battery cell (3) is arranged above the cell vent (5), wherein the cell vents (5) each have a seal (9) which is arranged circumferentially around the respective cell opening (8), wherein the projections (7) and / or the seals (9) space the battery cells (3) away from the base plate (10) by an oil space (11), wherein a [missing information] is attached to the base plate (10). Adhering to the wall, surrounding,A sealing arrangement (12) is arranged surrounding all cell vents (5) of the carrier plate (4), wherein the sealing arrangement (12) is U-shaped (12.1) in one piece and is provided with a further part (12.2) closing the U-shape (12.1) to the surrounding shape, wherein the further part (12.2) is preferably injected through at least one bore in the battery housing (2) after joining the carrier plate (4) to the battery housing (2). Traction battery (1) of a motor vehicle (100), comprising a plurality of battery cells (3), a battery housing (2) and a carrier plate (4), wherein the carrier plate (4) rests flatly on a wall of the battery housing (2) with a base plate (10), wherein the carrier plate (4) has cell vents (5) which are arranged above housing openings (6) of the battery housing (2), wherein the cell vents (5) each have a projection (7) on which one of the battery cells (3) is arranged such that a cell opening (8) of the battery cell (3) is arranged above the cell vent (5), wherein the cell vents (5) each have a seal (9) which is arranged circumferentially around the respective cell opening (8), wherein the projections (7) and / or the seals (9) space the battery cells (3) away from the base plate (10) by an oil space (11), wherein a [missing information] is attached to the base plate (10). Adhering to the wall, surrounding,A sealing arrangement (12) is arranged to enclose all cell vents (5) of the carrier plate (4), wherein the sealing arrangement (12) is provided in four parts with two sealing lines (12.3) along the joining direction (F) of the joining of the carrier plate (4) with the battery housing (2) and two further sealing lines (12.4), wherein the further sealing lines (12.4) are preferably injected through at least one bore in the battery housing (2) after the joining of the carrier plate (4) with the battery housing (2). Traction battery (1) according to one of the preceding claims, characterized in that static or dynamic turbulence generators (13), in particular flow fins, are provided on the base plate (10) in the oil space (11). Traction battery (1) according to one of the preceding claims, characterized in that channels (14) for guiding a coolant are provided on the base plate (10) in the oil chamber (11). Traction battery (1) according to one of the preceding claims, characterized in that the cell vents (5) are integrally sealed with the carrier plate, wherein the cell vents (5) have predetermined breaking points, in particular thinnings. Traction battery (1) according to one of claims 1 to 4, characterized in that the cell vents (5) have a cover (15), wherein the cover (15) is integrally connected with the respective seal (9) or is provided as a separate element bonded to the respective seal (9). Traction battery (1) according to one of the preceding claims, characterized in that the cell vents (5) and / or the housing openings (6) are covered with a metal foil (16). Method for manufacturing a traction battery (1) for a motor vehicle (100), comprising a plurality of battery cells (3), a battery housing (2), and a carrier plate (4), wherein the carrier plate (4) rests flatly on a wall of the battery housing (2) with a base plate (10), wherein the carrier plate (4) has cell vents (5) which are arranged above housing openings (6) of the battery housing (2), wherein the cell vents (5) each have a projection (7) on which one of the battery cells (3) is arranged such that a cell opening (8) of the battery cell (3) is arranged above the cell vent (5), wherein the cell vents (5) each have a seal (9) which is arranged circumferentially around the respective cell opening (8), wherein the projections (7) and / or the seals (9) space the battery cells (3) away from the base plate (10) by an oil space (11), characterized in that the Battery housing (2) is providedwherein a film (17) or strips (18) are arranged on the wall of the battery housing (2), wherein the carrier plate (4) with the battery cells (3) is inserted into the battery housing (2) along an assembly direction (F) on the film (17) or the strips (18), wherein the film (17) or the strips (18) are subsequently removed. Motor vehicle (100) comprising a traction battery (1) according to one of claims 1 to 7.

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