Battery for a motor vehicle, and motor vehicle

Abstract

The invention relates to a battery (10) for a motor vehicle, having a plurality of battery cells (12) and a battery housing (14) that encloses a housing interior (16) in which the battery cells (12) are received and which has a perforated sheet (20) on which the battery cells (12) are placed, wherein the perforated sheet (20) has, for each battery cell (12), an allocated degassing opening (28) on which the allocated battery cell (12) is placed and via which gas exiting the allocated battery cell (12) can be guided out of the housing interior (16).

Description

[0001] Battery for a motor vehicle and motor vehicle

[0002] The invention relates to a battery for a motor vehicle and a motor vehicle with a battery.

[0003] DE 10 2019 206646 A1 discloses an energy storage housing assembly for a motor vehicle, comprising an energy storage housing and an underrun protection guard secured to the underside of the energy storage housing. The underrun protection guard comprises a sandwich assembly with an upper cover plate on its upper side facing the energy storage housing and a lower cover plate on its underside. A filler is arranged between the upper cover plate and the lower cover plate, and the upper side of the sandwich assembly is profiled for webs or ribs.

[0004] DE 102011 103 993 A1 discloses a battery with a plurality of individual battery cells, which are connected to a cooling element on at least one of their end faces via elastic tolerance compensation elements, wherein an electrical insulation film is arranged between the individual battery cells and the cooling element. It is provided that the insulation film and the tolerance compensation elements are designed as one piece or are integrally connected to one another. Furthermore, DE 10 2019 200465 A1 discloses a battery module arrangement comprising a plurality of battery cells, each of the plurality of battery cells having a cell opening formed therein, and a plate arrangement defining a chamber, wherein the chamber accommodates a fluid therein.Furthermore, the battery module assembly comprises a plurality of openings extending through the plate assembly, wherein each of the plurality of openings is configured to be aligned with a cell opening of one of the battery cells.

[0005] Furthermore, WO 2022 / 031 056 A discloses a battery module and the

[0006] DE 102017 103654 B4 a battery housing for a vehicle battery.

[0007] It is the object of the invention to provide a solution which enables particularly reliable removal of hot gases from battery cells of a battery in the event of thermal runaway of a battery cell.

[0008] This object is achieved by the subject matter of the independent claims. Further possible embodiments of the invention are disclosed in the subclaims, the description, and the figures. Features, advantages, and possible embodiments presented in the description for one of the subject matter of the independent claims are to be regarded at least analogously as features, advantages, and possible embodiments of the respective subject matter of the other independent claims, as well as any possible combination of the subject matter of the independent claims, optionally in conjunction with one or more of the subclaims.

[0009] The invention relates to a battery for a motor vehicle, which is designed to provide electrical drive energy for an electric drive train of the motor vehicle. This means that the motor vehicle can be driven with electrical energy from the battery. The battery can in particular be a high-voltage storage device of the motor vehicle. The battery has a plurality of battery cells and a battery housing. The battery housing encloses an interior housing in which the battery cells are accommodated. Furthermore, the battery housing has a perforated plate on which the battery cells are placed. Placing the battery cells on the perforated plate means that the weight of the battery cells is supported by the perforated plate. When the battery is installed as intended in the motor vehicle, the battery cells are thus arranged above the perforated plate in the vertical direction of the vehicle.The battery cells can rest directly on the perforated sheet or indirectly on the perforated sheet via at least one other component. A cover of the battery housing forms a sandwich structure with the perforated sheet and the battery cells arranged between them. This sandwich structure allows for a particularly high overall rigidity of the battery.

[0010] The perforated plate has a dedicated vent for each battery cell, upon which the associated battery cell is placed. Gas escaping from the respective battery cell can be channeled out of the housing interior through this vent. Because the respective battery cells are placed on the perforated plate and, when properly installed, are arranged above the perforated plate in the vertical direction of the vehicle, any gases generated in the event of thermal runaway of a battery cell can be channeled downwards, away from the battery. By channeling the resulting gases downwards, the risk of these gases penetrating the passenger compartment of the vehicle can be kept particularly low.Furthermore, by directing the gases downwards from the respective battery cells, if the battery is arranged in a vehicle floor area of ​​the motor vehicle, the gases can be guided out of the motor vehicle via a particularly short route.

[0011] Thermal runaway of a battery cell and thermal propagation, the propagation of a thermal event from battery cell to battery cell within a battery, are among the greatest safety challenges in the operation of lithium-ion batteries, which are increasingly being used in the growing electromobility segment. By providing the perforated sheet with the venting openings to divert hot gases generated during thermal runaway of a battery cell away from the battery cells, thermal propagation can be particularly effectively prevented.

[0012] Each of the battery cells can completely cover the associated venting opening upwards in the vertical direction of the vehicle, thereby preventing gas from flowing back into the housing interior via the venting opening. Furthermore, a gas venting opening arranged underneath the battery cell can be reliably positioned above the associated venting opening. This ensures that a particularly large portion of the gas produced during thermal runaway of the battery cell, in particular all of the gas produced, is reliably diverted away from the battery cell via the venting opening, thus particularly reliably preventing gas from penetrating the housing interior. The associated venting openings can, in particular, be aligned with the gas venting openings of the associated battery cells.

[0013] The invention provides for a gap between the battery cells and the perforated sheet, the battery cells within the housing interior being foamed, and this foam seals the gap and the venting openings. This foam can be used to fill the volume of the housing interior not filled with battery cells or electronics, allowing all battery components to be securely held in their respective positions within the housing interior. This foam also penetrates the gap between the respective battery cells and the associated venting openings and seals the venting openings of the perforated sheet. The foam can harden in these venting openings of the perforated sheet, thereby providing the sealing layer.The foam is designed to melt upon contact with hot gases escaping from the respective battery cells, allowing the vents sealed by the foam to be opened, allowing the gases to escape from the housing interior. The foam can thus be used to secure all battery components within the housing interior and to seal the vents, particularly watertight.

[0014] Alternatively or additionally, the impact absorption foam is glued to a side of the perforated sheet opposite the battery cells. By gluing the impact absorption foam to the perforated sheet, the impact absorption foam is held particularly securely to the perforated sheet. Particularly in a battery design with both the impact absorption foam glued to the perforated sheet and the tray, the tray can be replaced particularly easily because the impact absorption foam is securely held to the perforated sheet.

[0015] In a possible further development of the invention, the perforated sheet is made of steel or aluminum. The perforated sheet made of aluminum is particularly lightweight. The perforated sheet made of steel is particularly stable and rigid, and consequently has a particularly long service life. It is also possible for the perforated sheet to be made of both steel and aluminum.

[0016] In a further possible embodiment of the invention, the venting openings are sealed by a sealing layer, in particular sealed in a watertight manner. This sealing layer is designed to be penetrated by hot gas escaping from the battery cells during thermal runaway. Thermal runaway is understood to mean the ignition or explosion of a battery cell as a result of exothermic reactions in the respective battery cells. In order to avoid a chain reaction from several battery cells up to all battery cells of the battery and thus to prevent the establishment of a self-sustaining reaction, the gases produced during thermal runaway of an individual battery cell are diverted via the associated venting opening.The sealing layer is provided to ensure the tightness of the housing interior during normal battery operation, particularly against water to prevent water from penetrating the housing interior. This sealing layer, together with the perforated sheet, provides predetermined breaking points by which the venting openings are closed during normal operation and through which the associated venting opening is opened in the event of thermal runaway caused by the hot gases. To open the sealing layer, the hot gases melt it at least locally, allowing the gas to escape from the housing interior through the exposed venting opening.The sealing layer thus ensures that the battery cells are particularly well protected against water penetration and, in addition, enables safe removal of hot gases in the event of thermal runaway of at least one of the battery cells via the respective venting openings of the perforated sheet.

[0017] In a further possible embodiment of the invention, the sealing layer comprises an adhesive layer, via which the battery cells are bonded to the perforated sheet, and / or the sealing layer comprises at least one plastic element that is applied to the perforated sheet. In other words, an adhesive can be spread onto the perforated sheet, which serves, on the one hand, to close the respective venting openings of the perforated sheet and, on the other hand, to bond the battery cells to the perforated sheet. The adhesive thus enables, on the one hand, the sealing, in particular, watertight sealing, of the housing interior and, on the other hand, the secure fastening of the battery cells in the housing interior.The adhesive allows the battery cells to be securely held to the perforated sheet, preventing any relative movement between the battery cells or between the battery cells and the battery housing, thereby keeping the risk of damage to the battery cells particularly low. The plastic element can, for example, be plastic plugs that are inserted into the respective venting openings in the perforated sheet in order to close the venting openings. Alternatively, the plastic element can be a plastic plate that is placed on the perforated sheet on the side facing towards the housing interior or on the side facing away from the housing interior, whereby at least one, in particular several, in particular all, venting openings in the perforated sheet are covered and thus sealed by the plastic plate.If only one plastic element is provided, it seals all venting openings of the perforated sheet. If multiple plastic elements are provided to provide the sealing layer, each of these plastic elements seals at least one venting opening, in particular multiple venting openings, of the perforated sheet. In the event of thermal runaway of the associated battery cell, the adhesive layer or the plastic element melts, at least in part, due to contact with the resulting hot gas, thereby exposing the associated venting opening of the perforated sheet. The hot gas can escape through this exposed venting opening.

[0018] In a further possible embodiment of the invention, a tray is arranged on a side of the perforated sheet opposite the battery cells, which tray, together with the perforated sheet, encloses a buffer volume in which an impact absorption foam is arranged. The tray, in particular together with the impact absorption foam, can provide underbody protection for the battery or the motor vehicle. The impact absorption foam can be designed specifically for the vehicle and used for different high-voltage storage systems. Alternatively or additionally, the impact absorption foam can be designed specifically for the storage system and used for different vehicles. The impact absorption foam is designed to protect the perforated sheet from mechanical damage such as scratches and, as a result, from corrosion. The tray can in particular be made from a metal or a fiber-reinforced plastic.For example, the tray has a sandwich structure consisting of two components stacked on top of each other, each made of a fiber-reinforced plastic, and a spacer, in particular a filler foam, between the components. The impact absorption foam is designed to be deformed in the event of a collision, thereby converting kinetic energy into deformation energy. This allows the battery cells to be particularly well protected against damage. The tray, in turn, is designed to hold the impact absorption foam. Furthermore, the tray is designed to prevent impacts from below when the battery is installed in the motor vehicle. The tray and the impact absorption foam thus enable a particularly long service life for the battery cells by providing them with particularly good protection against damage.Furthermore, the venting openings in the perforated sheet allow the hot gas generated during thermal runaway of the battery cells to be vented into the buffer volume. The gas generated during thermal runaway of at least one battery cell can be collected in this buffer volume and diverted away from the battery cells. Channels can be provided in the impact absorption foam to divert the hot gases away from the battery cells.

[0019] In this context, it can be provided, in particular, that the tray is tightly connected to the perforated sheet. This means that the buffer volume is tightly enclosed by the perforated sheet, especially if the sealing layer is present, and the tray. This prevents unwanted escape of hot gases from the buffer volume.

[0020] In a further possible embodiment of the invention, the tray is reversibly held on the battery housing. In particular, the tray can be replaced without causing any damage. In particular, if the tray is damaged, the damaged tray can be particularly easily removed from the battery housing and a new tray can be arranged and attached to the battery housing. A complete replacement of the entire battery if only the tray is damaged can therefore be avoided. The battery is therefore particularly sustainable and can be particularly easily repaired. The invention further relates to a motor vehicle with a battery as already described in connection with the battery according to the invention.

[0021] Further features of the invention may emerge from the claims, the figures, and the description of the figures. The features and combinations of features mentioned above in the description, as well as the features and combinations of features shown below in the description of the figures and / or in the figures alone, can be used not only in the respective combinations specified, but also in other combinations or on their own, without departing from the scope of the invention.

[0022] The drawing shows:

[0023] Fig. 1 shows a cross-section of a section of a battery for a motor vehicle;

[0024] Fig. 2 shows an enlarged section of the cross-section; and

[0025] Fig. 3 is a schematic perspective view of a perforated plate of the battery.

[0026] In the figures, identical and functionally identical elements are provided with the same reference numerals.

[0027] Fig. 1 shows a section through a battery 10 for a motor vehicle. The battery 10 has a plurality of battery cells 12 which are designed to provide electrical energy for an electric drive train of the motor vehicle. The battery 10 is in particular a traction battery for the motor vehicle. In addition to the plurality of battery cells 12, the battery 10 has a battery housing 14. This battery housing 14 encloses a housing interior 16 in which the plurality of battery cells 12 are accommodated. The battery housing 14 in the present case has a cover 18 and a perforated plate 20 which provides a base for the battery housing 14. The cover 18 delimits the housing interior 16 upwards in the vehicle's vertical direction z when the battery 10 is installed as intended in the motor vehicle, and the perforated plate 20 delimits the housing interior 16 downwards in the vehicle's vertical direction z.As can be seen in Fig. 1, the battery cells 12 are arranged above the perforated plate 20 in the vertical direction z of the vehicle. In particular, the battery cells 12 are supported by the perforated plate 20. For this purpose, the battery cells 12 can rest directly or indirectly on the perforated plate 20. The bottom of the battery housing 14 is formed in the present case by a high-voltage storage tray 22 having the perforated plate 20. This high-voltage storage tray 22 is made of steel in the present case and serves as a shear field. Both the high-voltage storage tray 22 and the cover 18 are connected in the present case via a first screw connection 24 to a sill 26 of the motor vehicle in the installed position of the battery 10 in the motor vehicle. The high-voltage storage tray 22 with the perforated plate 20 is shown separately in Fig. 3. As can be seen particularly clearly in Fig. 3, the perforated plate 20 has a plurality of venting openings 28. For reasons of clarity, Fig.3, only individual vent openings 28 are identified with the corresponding reference symbol. The perforated plate 20 has an associated vent opening 28 for each battery cell 12.

[0028] Fig. 2 shows a section of the battery 10, in which it can be seen particularly clearly that the respective battery cells 12 are arranged above the respective associated venting opening 28 in the vehicle's vertical direction z. The battery cell 12 completely covers the associated venting opening 28 in the vehicle's vertical direction z. The venting opening 28 is arranged, in particular, downwardly covering a gas vent opening of the battery cell 12 in the vehicle's vertical direction z. The gas vent opening of the battery cell 12 is arranged on an underside of the battery cell 12. Gas flowing out of the associated battery cell 12 via the gas vent opening, in particular hot gas, in particular as a result of thermal runaway of this battery cell 12, can thus be guided away from the relevant battery cell 12 via the associated venting opening 28.The hot gas generated during thermal runaway in the battery cell 12 can thus be removed from the housing interior 16 via the venting opening 28.

[0029] To ensure that the housing interior 16 is sealed watertight during normal operation of the battery 10 and thus in a case in which no thermal runaway of one of the battery cells 12 occurs, a sealing layer 30 is provided in the present case. This sealing layer 30 is arranged between the battery cells 12 and the perforated plate 20 and is designed to seal all venting openings 28 in a watertight manner. The sealing layer 30 can be provided by an adhesive or by a plastic component or by a foam. The sealing layer 30 is designed to open the venting opening 28 assigned to this battery cell 12 in the event of thermal runaway of the battery cell 12. This can be achieved by the sealing layer 30 melting locally and thus opening a passage from the battery cell 12 to the venting opening 28.Consequently, during normal operation of the battery 10, watertightness of the housing interior 16 can be ensured and, in addition, in the event of thermal runaway of one of the battery cells 12, it can be ensured that hot gases generated can be guided away from the housing interior 16 via the associated venting opening 28.

[0030] As can be seen in Figs. 1 and 2, a tray 32 can be arranged in the vehicle's vertical direction z below the battery housing 14, which serves as bollard protection. This tray 32 can be a replaceable base plate for the battery 10. In the present case, the replaceable base plate has a sandwich structure consisting of a first glass fiber reinforced plastic component 34, a foam 36 and a second glass fiber reinforced plastic component 38. The tray 32 is attached to the high-voltage storage tray 22 via at least one second screw connection 42 and to the sill 26 via at least one third screw connection 44. The at least one second screw connection 42 and the at least one third screw connection 44 enable non-destructive, reversible replaceability of the tray 32 on the battery housing 14 of the battery 10 and on the sill 26 of the motor vehicle. As shown in Figs. 1 and 22, the tray 32, together with the perforated plate 20, defines a buffer volume 46. An impact absorption foam 48 can be arranged in this buffer volume 46. This impact absorption foam 48 can be glued to the perforated plate 20 on an underside of the perforated plate 20 facing away from the battery cells 12. As a result, the impact absorption foam 48 is particularly securely fixed in the buffer volume 46. This impact absorption foam 48 is a support structure for the battery 10 and serves as a sacrificial component in the event of an impact from below.

[0031] The described battery 10 enables an improvement in the overall rigidity of the motor vehicle while simultaneously improving repairability in the event of minor damage. Furthermore, the battery 10 enables a weight reduction compared to conventional batteries for the respective motor vehicles.

[0032] In the described battery 10, the perforated plate 20 is provided below the battery cells 12 in the vehicle's vertical direction z, and below the perforated plate 20 is the foam integrated into a removable protective component, in this case the tray 32, in this case the impact absorption foam 48. To prevent thermal propagation of the battery cells 12 by diverting resulting gases into the impact absorption foam 48, the housing base is provided with the perforated plate 20. This allows the battery cells 12 to be degassed into the buffer volume 46 enclosed by the removable tray 32.

[0033] The battery cells 12 can be glued to the perforated sheet 20 from above. In this case, the venting openings 28 are sealed watertight with an adhesive. Alternatively or additionally, the venting openings 28 are sealed with a plastic component. The perforated sheet 20 can be made of aluminum or steel and has a venting opening 28 below each battery cell 12. The venting openings 28 are sealed in such a way that venting of the associated battery cells 12 is possible. This means that hot gas from the battery cell 12 can penetrate the seal. The impact absorption foam 48, in which the venting of the battery cells 12 is possible, is arranged below the perforated sheet 20. The impact absorption foam 48 serves to cushion any impact on the battery 10 from below. This impact absorption foam 48 is pre-assembled in the tray 32 which can be removed from the motor vehicle and is glued to the perforated sheet 20 from below.The tub 32 can be made of plastic, in particular of glass fiber reinforced plastic, and / or of light metal.

[0034] If the sealing layer 30 is not provided, the housing interior 16 can be sealed downwards by means of the tray 32 in order to prevent water from penetrating into the housing interior 16.

[0035] The sandwich construction of the battery 10, consisting of a housing upper part or cover 18, the battery cells 12, and the perforated sheet 20, enables a particularly high overall rigidity of the battery 10. This results in a functional separation between the battery housing 14 and the tray 32, which provides underrun protection in combination with the impact absorption foam 48. The tray 32, together with the impact absorption foam 48, performs the functions of propagation protection and underrun protection. Overall, the invention shows how a sandwich high-voltage storage base with degassing passages, in this case the degassing openings 28, can be provided for cell propagation.

[0036] List of reference symbols

[0037] 10 Battery

[0038] 12 battery cells

[0039] 14 Battery housing

[0040] 16 Housing interior

[0041] 18 lids

[0042] 20 perforated sheets

[0043] 22 Case back

[0044] 24 first screw connection

[0045] 26 sills

[0046] 28 Degassing opening

[0047] 30 waterproofing layer

[0048] 32 tub

[0049] 34 first glass fiber reinforced plastic component

[0050] 36 foam

[0051] 38 second glass fiber reinforced plastic component

[0052] 42 second screw connection

[0053] 44 third screw connection

[0054] 46 buffer volumes

[0055] 48 Impact absorption foam z Vehicle vertical direction x Vehicle longitudinal direction y Vehicle transverse direction

Claims

New patent claims Battery (10) for a motor vehicle, with a plurality of battery cells (12) and a battery housing (14), which encloses a housing interior (16) in which the battery cells (12) are accommodated, and which has a perforated plate (20) on which the battery cells (12) are placed, wherein the perforated plate (20) has for each battery cell (12) an associated venting opening (28), on which the associated battery cell (12) is placed and via which gas escaping from the respective associated battery cell (12) can be guided out of the housing interior (16), wherein a gap is provided between the battery cells (12) and the perforated plate (28), the battery cells (12) are foamed in the housing interior (16), and this foam closes the gap and the venting openings (28), and / or an impact absorption foam (48) is applied to a side opposite the battery cells (12) of the perforated plate (20) is glued.Battery (10) according to claim 1, characterized in that the battery cells rest directly on the perforated sheet (20). Battery (10) according to claim 1 or 2, characterized in that the venting openings (28) are sealed by means of a sealing layer (30) which is designed to be penetrated by hot gas flowing out of the battery cells (12) in the event of thermal runaway. Battery (10) according to claim 3, characterized in that the sealing layer (30) has an adhesive layer, via which the battery cells (12) are glued to the perforated sheet (20), and / or the. The sealing layer (30) comprises at least one plastic element that is applied to the perforated sheet (28). Battery (10) according to one of the preceding claims, characterized in that a tray (32) is arranged on a side of the perforated sheet (20) opposite the battery cells (12), which tray, together with the perforated sheet (20), encloses a buffer volume (46) in which an impact absorption foam (48) is arranged. Battery (10) according to claim 5, characterized in that the tray (32) is tightly connected to the perforated sheet (20). Battery (10) according to claim 5 or 6, characterized in that the tray (32) is reversibly held on the battery housing (14). Motor vehicle with a battery (10) according to one of the preceding claims.

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