Motor vehicle with a traction battery module

Abstract

Motor vehicle (100) with a traction battery module (10) comprising a hermetically sealed module housing (20) in which at least one cell stack pair (600) consisting of a left and a right cell stack (60, 60') each comprising at least two battery cells (62) is enclosed, wherein the traction battery module (10) is arranged in the vehicle floor (102), extends symmetrically to the vehicle center (M) in the vehicle transverse direction (X) over most of the width of the vehicle floor (102) and has a floor wall (26) in a horizontal plane, wherein a gas space (66) is formed in the module housing (20) in the vehicle center (M) and with respect to the vehicle transverse direction (X) between the left cell stack (60) and the right cell stack (66'), wherein the gas space (66) is substantially cuboidal and extends in the vertical direction (Z) over the entire vertical extent of a cell stack (60,60') extends,and extends in the longitudinal direction (Y) of the vehicle over the entire longitudinal extent (L) of a cell stack (60, 60'), wherein the module floor wall (26) has a degassing element (30) centrally located in the area of ​​the gas space (66), and wherein a flat and liquid-cooled cooling floor (40) is arranged below the module floor wall (26), which has a degassing opening (46) centrally located in the vehicle in a vertical orientation with the degassing element (30).

Description

[0001] The invention relates to a motor vehicle with a traction battery module that supplies an electric traction motor of the motor vehicle with electrical energy.

[0002] Automotive traction battery modules have a hermetically sealed module housing, in which several cell stacks, each consisting of multiple battery cells, are typically enclosed in a gas-tight manner. In the event of a thermal incident, gases at very high temperatures can suddenly escape from the cell stack and must be vented from the module housing. DE 10 2018 221 990 A1 discloses a traction battery with a multitude of battery cells within a battery housing that has a lateral degassing element in the form of a burst zone. This zone ruptures at a sufficiently high internal gas pressure, allowing the gas to escape in that area. The battery cells are located at varying distances from the degassing element, so that the high-temperature gas flow from one battery cell may significantly heat several other battery cells on its way to the degassing element.

[0003] Against this background, the object of the invention is to create a motor vehicle traction battery with improved hot gas discharge.

[0004] This problem is solved according to the invention with a motor vehicle having a traction battery module having the features of claim 1.

[0005] The vehicle according to the invention comprises a traction battery module with a hermetically sealed module housing in which at least one cell stack pair is arranged. The module housing is substantially gas-tight. Each cell stack pair consists, relative to the vehicle's longitudinal axis, of a left cell stack and a right cell stack. Each cell stack comprises at least two battery cells. The traction battery module is located in the vehicle floor and extends symmetrically to the vehicle's centerline in the transverse direction. The module housing has a bottom wall lying in a horizontal plane. Within the module housing, approximately at the vehicle's centerline, a free gas space is formed between the left cell stack and the right cell stack, which is not filled with any filler material, in particular not with a thermally conductive compound.The module's bottom wall features a degassing element in the gas space, approximately in the center of the vehicle. This element allows any high-temperature gas escaping from one of the battery cells in the center of the vehicle to escape downwards from the vehicle floor to the vehicle's exterior. The traction battery module is designed such that each cell stack is fluidically connected directly to the gas element. This allows the high-temperature gas escaping from each cell stack to flow directly through the gas space to the degassing element without passing significantly by another cell stack. This reliably prevents a chain reaction within the traction battery module. Because degassing occurs directly towards the underside of the vehicle via the degassing element, a short flow path from each cell stack to the degassing element is achieved, ensuring localized heating of the traction battery module.Furthermore, the direct escape of the high-temperature gas towards the central underside of the vehicle ensures good occupant protection.

[0006] Preferably, the gas space is essentially cuboid and has a width of at least 10 cm in the transverse direction of the vehicle. Preferably, the gas space has a width of no more than 30 cm in the transverse direction of the vehicle. Preferably, the gas space extends vertically over the entire vertical extent of the adjacent cell stack or longitudinally over the entire longitudinal extent of the adjacent cell stack. Thus, each cell stack abuts the gas space with one side almost completely. In this way, it is ensured that the flow resistance between each cell stack and the gas space is approximately zero and that an overpressure can build up in the gas space as quickly as possible, thereby opening the degassing element.

[0007] Preferably, the degassing element is designed as a gas-tight rupture disc. The rupture disc is designed to reliably rupture at a significant overpressure, thus reliably opening the degassing element in the event of a thermal malfunction. The rupture disc can, for example, be implemented simply as a weakening of the material in the bottom wall of the module housing, or it can be designed as a mechanical pressure relief valve that closes again after the internal overpressure has dissipated.

[0008] Preferably, the vehicle has a flat, liquid-cooled cooling floor beneath the module floor wall, through which the underside of the traction battery module is actively cooled. The cooling floor has a centrally located degassing opening, aligned vertically with the degassing element in the transverse direction of the vehicle. This ensures that the degassing of the traction battery module is not obstructed by the cooling floor in the event of a malfunction.

[0009] Preferably, two pairs of cell stacks can be provided within the module housing, arranged adjacent to each other in the longitudinal direction of the vehicle. In principle, a single degassing element can be assigned to the center of each of the two gas spaces. However, it is particularly preferred that the two pairs of cell stacks and their respective gas spaces are gas-tightly insulated from one another, with each gas space having its own dedicated degassing element.

[0010] Preferably, four side walls of the module housing are formed in one piece from an extruded profile.

[0011] An embodiment of the invention will be explained in more detail below with reference to the drawings. The drawings show: Fig. 1 schematically a motor vehicle with a traction battery module in the vehicle floor, Fig. 2 the traction battery module of the Fig. 1 in cross-section, Fig. 3 the traction battery module of the Fig. 1 and Fig. 2 in horizontal section, and Fig. 4. An underside view of the vehicle floor onto a cooling floor below the traction battery module. Fig. 1-3.

[0012] In the Fig. Figure 1 schematically depicts a motor vehicle 100 with an electric traction motor 104, which has several traction battery modules 10 in the vehicle floor 102, which together form the traction battery of the motor vehicle 100. The direction of travel of the motor vehicle 100 is the longitudinal direction Y, the lateral direction is the transverse direction X, and its vertical axis is the vertical axis Z.

[0013] Each traction battery module 10 has two cell stack pairs 600, 600', each consisting of a left cell stack 60 and a right cell stack 60', with the left cell stack 60 located in the left half of the vehicle to the left of the vehicle center M and the right cell stack 60' in the right half of the vehicle to the right of the vehicle center M. The traction battery module 10 extends substantially over most of the width of the vehicle floor 102. Each cell stack 60, 60' consists of several battery cells 62, which are arranged in a vertical transverse plane such that a proximal narrow side of each battery cell 62 adjoins a module-centered, cuboid gas space 66, which is a free space not filled with a solid. The gas space 66 extends longitudinally over the entire longitudinal extent and vertically over the entire vertical extent of the two adjacent cell stacks 60, 60'.The cuboid gas space 66 has a width B of, for example, 20 cm in the transverse direction X of the vehicle.

[0014] The cuboid, gas-tight sealed metal module housing 20 has a left side wall 21, a right side wall 22, a top wall 25, a bottom wall 26, a front end wall 23, and a rear end wall 24. The module housing 20 is partially formed by an extruded profile body, which forms the four long housing walls 21, 22, 25, 26, and a partition wall 80, whereas the relatively small left side wall 21 and right side wall 22 were gas-tightly mounted to the extruded profile body after the two cell stack pairs 600, 600' were inserted into the profile body, for example, by welding.

[0015] With respect to the transverse direction x, a degassing element 30 is arranged in the floor wall 26 in the area of ​​the vehicle center M and approximately in the middle of the respective gas space 66, 66'. This element is generally gas-tight, but is designed to be permanently destroyed if a defined differential pressure between the gas space 66, 66' and the outside atmospheric pressure is exceeded. Each degassing element 30 is formed by a rupture disc 32, which is gas-tightly seated in a degassing opening 28 in the floor wall 26.

[0016] Adjacent to the bottom wall 26 of the module housing 20 is a liquid-cooled cooling floor 40, which is actively and almost completely cooled by a coolant 44 flowing through a cooling channel 42. The cooling floor 40 is thermally coupled to the module housing bottom wall 26 across its entire surface, so that during charging or traction operation, most of the heat generated by the traction battery module 10 is dissipated via the cooling floor 40. The cooling floor 40 has a corresponding degassing opening 46 in a vertical orientation with the degassing element 30, through which, in the event of degassing, the gas from the gas space 66 can escape vertically downwards towards the center of the vehicle.

[0017] In the horizontal section of the Fig.Figure 3 shows that the outer module housing 20 contains two cell stack pairs 60,60' which are separated gas-tight from each other by the partition wall 80 which stands in a vertical transverse plane, so that each cell stack pair 600,600' has its own gas space 66,66' and its own degassing element 30,30. QUOTES INCLUDED IN THE DESCRIPTION

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

[0000] DE 102018221990 A1

[0002]

Claims

[1] Motor vehicle (100) with a traction battery module (10) having a hermetically sealed module housing (20) in which at least one cell stack pair (600) consisting of a left and a right cell stack (60,60') each consisting of at least two battery cells (62) is enclosed, wherein the traction battery module (10) is arranged in the vehicle floor (102), extends symmetrically to the vehicle center (M) in the vehicle transverse direction (X) and has a floor wall (26) in a horizontal plane, wherein a gas space (66) is formed in the module housing (20) in the center of the vehicle (M) and with respect to the transverse direction of the vehicle (X) between the left cell stack (60) and the right cell stack (66'), wherein the module bottom wall (26) has a degassing element (30) in the area of ​​the gas space (66) in the center of the vehicle. [2] Motor vehicle (100) with a traction battery module (10) according to claim 1, wherein the gas space (66) is substantially cuboid and has a width (B) of at least 10 cm in the transverse direction (X) of the vehicle. [3] Motor vehicle (100) with a traction battery module (10) according to one of the preceding claims, wherein the gas space (66) is substantially cuboid and has a width (B) of at most 30 cm in the transverse direction (X) of the vehicle. [4] Motor vehicle (100) with a traction battery module (10) according to one of the preceding claims, wherein the gas space (66) is substantially cuboid and extends in the vertical direction (Z) over the entire vertical extent of a cell stack (60,60'). [5] Motor vehicle (100) with a traction battery module (10) according to one of the preceding claims, wherein the gas space (66) is substantially cuboid and extends in the longitudinal direction (Y) of the vehicle over the entire longitudinal extent (L) of a cell stack (60,60'). [6] Motor vehicle (100) with a traction battery module (10) according to one of the preceding claims, wherein the degassing element (30) is designed as a gas-tight burst disc (32). [7] Motor vehicle (100) with a traction battery module (10) according to one of the preceding claims, wherein a flat and liquid-cooled cooling floor (40) is arranged below the module floor wall (26), which has a vehicle-central degassing opening (46) in a vertical orientation with the degassing element (30). [8] Motor vehicle (100) with a traction battery module (10) according to one of the preceding claims, wherein at least two cell stack pairs (600, 601) are provided which are arranged adjacent to each other in the longitudinal direction (Y) of the vehicle, wherein the two gas spaces (66, 66') are gas-tightly insulated from each other and each gas space (66, 66') is assigned its own degassing element (30, 30'). [9] Motor vehicle (100) with a traction battery module (10) according to one of the preceding claims, wherein four side walls (21-24) of the module housing (20) are formed in one piece from an extrusion profile.

Images