Battery device for an at least partially electrically powered motor vehicle

Abstract

Battery device (1) for a motor vehicle that is at least partially electrically powered, comprising at least one housing (2) with at least one housing compartment (12) and bag-like battery cells (3) housed in the housing compartment (12), wherein the battery cells (3) are arranged in the housing compartment (12) to form at least one cell stack (33), and wherein the battery cells (3) each have a cell housing (13) with at least one cell venting opening (23), and wherein the housing (2) has at least one housing wall (22) with housing venting openings (32), and wherein the housing venting openings (32) are arranged at least sectionally opposite each other to at least one corresponding cell venting opening (23), and wherein each cell venting opening (23) is opposite only one housing venting opening (32).wherein the housing degassing openings (32) are each longer in a first extension plane (14) than in a second extension plane (24) and wherein the cross-sectional area of ​​each housing degassing opening (32) differs by no more than 25% from the cross-sectional area of ​​the corresponding cell degassing opening (23), characterized by that the housing (2) is provided by an extruded profile and that the housing degassing openings (32) are each equipped with a web element (4) extending transversely to the first extension plane (14) and through the respective housing degassing opening (32), which divides the housing degassing opening (32) into two opening sections (42) and that the arrangement in the cell stack (33) is in the direction of the second extension plane (24), so that the forces arising from an operational swelling of the battery cells (3) and acting on the housing (2) are introduced into the web elements (4).

Description

[0001] The present invention relates to a battery system for a motor vehicle that is at least partially electrically powered and comprises at least one housing with at least one housing compartment and battery cells housed in the housing compartment. Each battery cell has a cell housing with at least one cell venting opening. The housing has at least one housing wall with housing venting openings. The housing venting openings are arranged at least partially opposite each other to at least one corresponding cell venting opening.

[0002] In the event of a malfunction, such as a thermal runaway (also known as a thermal event) of the battery cells, a significant amount of gas is typically produced, which must be vented from the battery cells and the casing. This gas is released from the otherwise sealed battery system via the cell vents and the casing vents, which therefore require a sufficiently large cross-sectional opening. However, this requirement conflicts with the need for a stable and safe casing. This is particularly critical if the casing must accommodate the operational expansion of the battery cells (cell swelling).

[0003] A battery device of this type is known from DE 10 2022 100 060 A1.

[0004] German patent DE 10 2021 202 052 A1 discloses a battery system comprising a module housing and a cell stack in which heat-resistant partitions are arranged. This divides the module housing into gas-tight, separated compartments. Combustion gases can be vented from the respective compartments via outlet openings in the module housing, while the other compartments remain free of exhaust gases.

[0005] German patent DE 10 2018 206 793 A1 discloses a battery device with a cover designed as a perforated plate with a plurality of openings. The openings are covered with a film that is at least partially destructive by temperature and / or pressure in order to expose the openings.

[0006] US patent 2012 O 164 490 A1 discloses a battery module with a release mechanism for the safe venting of gases from the battery housing. The battery cells are equipped with a rigid cylindrical housing. The cell venting ports are cylindrical.

[0007] EP 3 790 101 A1 discloses a battery module with battery cells arranged longitudinally, each with its own rigid housing. Each battery cell has a vent, to which several slot-like housing degassing openings are assigned. An extinguishing foil releases an extinguishing agent when a certain temperature is exceeded.

[0008] US patent 2022 0 320 673 A1 discloses a battery whose battery cells have a pressure relief mechanism. At elevated temperatures, the pressure relief mechanism opens at a predetermined angle, allowing gases to escape.

[0009] CN 114 497 873 A shows a battery module with an upper module cover in which exhaust vents are formed. This allows hot gases to enter an exhaust duct and be released via an explosion protection valve.

[0010] In contrast, the object of the present invention is to provide a battery device with a reliable means of degassing in the event of a malfunction, which at the same time has no undesirable effect on the stability of the housing. The solution should preferably be particularly stable and at the same time be structurally simple and space-saving.

[0011] This problem is solved by a battery device having the features of claim 1. Preferred embodiments of the invention are the subject of the dependent claims. Further advantages and features of the present invention will become apparent from the general description and the description of the exemplary embodiment.

[0012] The battery system according to the invention is intended for a motor vehicle that is at least partially electrically powered. The battery system is designed, in particular, as a high-voltage battery and preferably as a traction battery. The battery system comprises at least one housing with at least one housing compartment and bag-like battery cells housed in the housing compartment. The battery cells are arranged in at least one cell stack within the housing compartment. Each battery cell has a cell housing with at least one (preferably only one) cell venting opening. The housing has at least one housing wall with housing venting openings. The housing venting openings are arranged at least sectionally opposite each other to at least one corresponding cell venting opening. Each cell venting opening is located opposite only one housing venting opening.The housing vents are each longer in a first dimension plane than in a second dimension plane. The cross-sectional area of ​​each housing vent deviates by no more than 25% from the cross-sectional area of ​​the corresponding cell vent. The housing is provided by at least one extruded profile. Each housing vent is equipped with a web element extending transversely to the first dimension plane and through the respective housing vent. The web element divides the housing vent into two opening sections. The cells are arranged in the cell stack in the direction of the second dimension plane, so that the forces generated by operational swelling of the battery cells and acting on the housing are transferred into the web elements.

[0013] The battery device according to the invention offers many advantages. A significant advantage is provided by the elongated housing venting openings. This enables reliable gas removal even with very slim battery cells and correspondingly narrow cell venting openings. The rib elements extending transversely to the first dimension plane are also particularly advantageous. These enable effective, yet structurally simple and space-saving stabilization of the elongated housing venting openings. As a result, the rib elements can absorb forces acting on the housing wall, especially those extending towards the second dimension plane. Such forces are primarily caused by an operational increase in the volume of the battery cells. Otherwise, such forces could lead to undesirable stress and, for example, elongation of the housing or the housing venting openings towards the second dimension plane.

[0014] According to the invention, the cells are arranged in the stack along the second plane of extension. In particular, the cells are arranged in the stack in the same direction as the web elements. According to the invention, this transfers the forces acting on the housing due to operational swelling of the battery cells into the web elements or absorbs them. These forces, in particular, predominantly act along the longitudinal axis of the web elements. The battery cells are thus pre-tensioned within the housing to prevent operational swelling. The operational swelling of the battery cells is transferred to the housing and the web elements.

[0015] It is preferred and advantageous that the web elements are each firmly and preferably integrally connected to the housing wall. In particular, the web elements are an integral part of the housing wall. Specifically, the web elements are firmly connected to the housing wall on opposite sides of the housing vent opening. According to the invention, the web elements extend through the respective housing vent opening. In particular, the web element connects the opposite sides of the housing vent opening (according to the principle of a tie rod). It is possible that the web elements are integrated into the material of the housing wall. The web elements can be connected to the housing wall by frictional, positive, or material bonding.

[0016] It is possible and advantageous for the casing venting openings to be at least twice as long in the first dimension plane as in the second dimension plane. Such dimensions are particularly advantageous for narrow battery cells with a high energy or power density, as this results in correspondingly long cell venting openings.

[0017] In particular, the housing vent openings are closed by means of at least one overpressure element and are sealed in a media-tight manner. Preferably, the overpressure element is suitable and designed to at least partially release the housing vent opening in a pressure-initiated and / or temperature-initiated manner. The overpressure element is specifically designed to withstand the temperatures and pressure conditions expected in the event of a malfunction. It is possible for one overpressure element to serve several housing vent openings. It is also possible for at least one overpressure element to be provided for each housing vent opening.

[0018] In a particularly preferred and advantageous embodiment, at least the opening sections belonging to each housing venting opening are closed by at least one common overpressure element. Such a common overpressure element can serve for several housing venting openings. However, it is also possible that at least one common overpressure element is provided for each housing venting opening.

[0019] It is possible and advantageous for the overpressure element (especially around the housing vent opening) to be bonded to the housing wall by a material-bonded connection, preferably by welding or bonding. The overpressure element can also be attached to the housing wall in another suitable manner.

[0020] It is preferred and advantageous that the overpressure element is connected to the web element, at least partially. Preferably, the overpressure element is connected to the web element in the same way as it is connected to the housing wall. However, a different type of connection can also be provided for the connection to the web element. It is also possible that the overpressure element is not attached to the web element.

[0021] In an advantageous embodiment, the overpressure element is designed and configured to detach, at least partially, from the housing wall and / or the bridge element under pressure and / or temperature-initiated conditions. For this purpose, the overpressure element is attached, in particular, by a selectively releasable adhesive bond and / or welded connection. Specifically, the overpressure element is designed as an adhesive pad (adhesive patch) or welded pad (welded patch).

[0022] It is also possible and advantageous for the overpressure element to be suitable and designed to tear under pressure and / or temperature. For this purpose, the overpressure element preferably has at least one predetermined breaking point. For example, the overpressure element can be designed as a tearable foil element. Tearing is understood to include, in particular, breaking.

[0023] In a preferred and advantageous embodiment, the web elements are produced by selectively removing material from the area of ​​the opening sections during the manufacturing of the housing degassing openings. Preferably, the material removal is carried out by waterjet cutting and / or laser cutting and / or a machining process (for example, milling). In particular, the web elements are machined out in this way. Specifically, the material removal takes place from the housing wall or its blank. Preferably, a hollow profile with one or more hollow chambers, and preferably an extruded profile, is machined.

[0024] It is possible that the housing space is provided by a hollow chamber and preferably a central main chamber. It is also possible that the housing is formed from several hollow profiles. In this case, at least one housing wall is provided by at least one hollow profile.

[0025] In an advantageous embodiment, the housing degassing openings are at least partially aligned (and spaced apart) in the direction of the second extension plane. It is possible and preferred that the web elements (in particular, the web elements of the housing degassing openings arranged in a row) are arranged at least partially along a common longitudinal axis extending in the direction of the second extension plane. In particular, the housing degassing openings are arranged in the direction of the cell stack. It is also possible that the web elements are arranged offset from their common longitudinal axis.

[0026] In a preferred embodiment, the housing is a modular housing for a battery module. In particular, the battery assembly comprises at least one battery module and preferably a plurality of battery modules. Specifically, the at least one battery module is enclosed in a main housing.

[0027] In particular, the web elements extend along their longitudinal axis in the direction of the second plane of extension. Specifically, the web elements have a longitudinal axis that runs parallel to the second plane of extension and / or to the arrangement in the cell stack. The specifications regarding the plane of extension refer in particular to the cross-sectional area of ​​the housing degassing openings.

[0028] In particular, the housing venting openings each correspond to only one cell venting opening. According to the invention, each cell venting opening is located opposite only one housing venting opening. In particular, the housing venting openings have an outer contour that is at least partially rounded. This allows the housing to better absorb the stresses caused by the swelling of the battery cells.

[0029] Preferably, the housing degassing openings correspond at least approximately in shape and / or size to the cell degassing openings. According to the invention, the cross-sectional area of ​​each housing degassing opening deviates from the cross-sectional area of ​​the corresponding cell degassing opening by no more than 25%, preferably by no more than 10%, and particularly preferably by no more than 5%. In particular, the cell degassing openings are also each longer in a first plane of extension than in a second plane of extension.

[0030] In particular, the battery cells are electrically interconnected within the housing.

[0031] In particular, the battery cells each comprise two opposing main sides and narrow sides extending transversely to the main sides. Specifically, the narrow sides extend between the main sides. In particular, the at least one cell vent of a battery cell is formed in at least one of its narrow sides.

[0032] In particular, the battery cells are arranged in the cell stack such that their main sides face each other. Specifically, the main sides lie within the cell stack. Specifically, the main sides point in the direction of the second extension plane. Specifically, the narrow sides of the battery cells arranged in the cell stack point outwards. Specifically, the narrow sides run perpendicular to the main sides.

[0033] Further advantages and features of the present invention will become apparent from the exemplary embodiments, which are explained below with reference to the accompanying figures.

[0034] The figures show: Fig. 1 a highly schematic representation of a battery device according to the invention in a perspective view from an oblique angle above on a bottom surface; Fig. 2 the battery system of the Fig. 1 in a partially transparent perspective view; Fig. 3 another illustration of the battery arrangement of the Fig. 1 in a perspective view; and Fig. 4 a representation of the battery arrangement of the Fig. 1 in a cutaway side view.

[0035] The Fig. Figure 1 shows a battery device 1 according to the invention with a housing 2, which here is designed as a module housing 62 of a battery module 10. The battery device 1 can comprise further battery modules 10, not shown here, which can be interconnected, for example, to provide a high-voltage battery for powering an at least partially electrically powered motor vehicle. The battery device 1 is described below with reference to the Fig. 1 to 4 are described in more detail.

[0036] In the housing compartment 12 of the housing 2, a plurality of battery cells 3 are housed, which are shown in the transparent representation of the Fig. 2 are clearly visible. The battery cells 3 are designed here as prismatic-type lithium-ion battery cells and each comprises a cell housing 13 with a cell vent 23 for the removal of gases in the event of a thermal event. The electrochemical components of the battery cell 3 are housed in the cell housing 13.

[0037] The battery cells 3 have two opposing main sides 43 and narrow sides 53 extending transversely to the main sides. The battery cells 3 are arranged in four cell stacks 33 within the housing space 12. The battery cells 3 are arranged such that their main sides 43 are aligned with each other within the cell stack 33. The narrow sides 53 face outwards. The cell degassing openings 23 are each formed on one of the narrow sides 53.

[0038] The battery cells 3 arranged in a row are pre-tensioned in the housing 2, so that the pressure on the housing 2 also increases due to operational swelling.

[0039] The amount of gas that flows out of battery cell 3 per unit time in the event of a thermal event is generally dependent on the cell chemistry used. As a rule, higher power and energy densities lead to a greater amount of gas. The greater the amount of gas to be discharged per unit time, the larger the degassing opening must be. Due to the correspondingly narrow battery cells 3 used here, the cell degassing openings 23 are therefore also particularly narrow and elongated.

[0040] As seen in the overview of Fig. 1 and Fig. As can be clearly seen in Figure 2, the cell degassing openings 23 are covered by a housing wall 22 of the housing 2. Housing degassing openings 32 are formed in the housing wall 22, each dimensioned and arranged to correspond to a cell degassing opening 23. The housing degassing openings 32 and also the cell degassing openings 23 are longer in a first extension plane 14 and, for example, at least twice as long as in a second extension plane 24.

[0041] To reliably prevent the elongated housing degassing openings 32 used here from leading to an undesirable weakening of the housing wall 22 and thus also of the entire housing 2, the housing degassing openings 32 are equipped with web elements 4. The web elements 4 extend transversely to the first extension plane 14 and divide the housing degassing opening 32 into two opening sections 42. The web elements 4 used here have the advantage that they ensure the preservation of housing stability even with correspondingly large or elongated cell degassing openings 23, without adversely restricting the opening cross-section of the cell degassing openings 23.

[0042] The web elements 4 serve to stabilize the housing 2, in particular against stress on the housing 2 due to an operational increase in the volume of the battery cells 3. The stress caused by the swelling of the battery cells 3 has the force direction 6 sketched here by the arrows. The web elements 4 extend parallel to this force direction 6.

[0043] The housing venting openings 32 are closed by means of overpressure elements 5 during normal operation. The overpressure elements 5 open in the event of a thermal event due to the overpressure generated in the housing chamber 12. In this case, the two opening sections 42 of each housing venting opening 32 are closed by a common overpressure element 5 (as shown in the Fig. 3 (clearly visible). The overpressure elements 5 are designed here, for example, as tearable films or as removable adhesive pads or sweat pads.

[0044] The web elements 4 are an integral part of the housing wall 22 and are, for example, formed integrally with the housing wall 22. For this purpose, the housing degassing openings 32 are produced, for example, by removing material in the area of ​​the opening sections 42, so that the web elements 4 are formed. The housing 2 can, for example, be provided by a hollow profile 52 or at least partially be composed of one or more hollow profiles 52.

[0045] Future electrochemical components will enable higher energy and power densities for the battery cells 3, necessitating increasingly larger cell degassing openings 23. The longer the cell degassing opening 23, the greater the weakening of the housing 2 typically becomes. This can lead to adverse stresses on the housing 2 caused by the swelling of the battery cells 3. The invention presented here offers a simple yet highly reliable solution to counteract this weakening of the housing 2. Furthermore, the improved module housing stability also results in a weight advantage, which, for example, impacts the range of an electric vehicle. Reference symbol list: 1 Battery unit 2 cases 3 battery cells 4 bridge element 5 Overpressure element 6 Direction of force 10 battery modules 12 Housing space 13 cell casings 14 Extension level 22 Housing wall 23 Cell degassing opening 24 Extension level 32 Housing degassing opening 33 cell stacks 42 Opening section 43 Main page 52 Hollow profile 53 Narrow side 62 module housings

Claims

[1] Battery device (1) for a motor vehicle that is at least partially electrically powered, comprising at least one housing (2) with at least one housing compartment (12) and bag-like battery cells (3) housed in the housing compartment (12), wherein the battery cells (3) are arranged in the housing compartment (12) to form at least one cell stack (33), and wherein the battery cells (3) each have a cell housing (13) with at least one cell venting opening (23), and wherein the housing (2) has at least one housing wall (22) with housing venting openings (32), and wherein the housing venting openings (32) are arranged at least sectionally opposite each other to at least one corresponding cell venting opening (23), and wherein each cell venting opening (23) is opposite only one housing venting opening (32).wherein the housing degassing openings (32) are each longer in a first extension plane (14) than in a second extension plane (24) and wherein the cross-sectional area of ​​each housing degassing opening (32) differs by no more than 25% from the cross-sectional area of ​​the corresponding cell degassing opening (23), characterized by , that the housing (2) is provided by an extruded profile and that the housing degassing openings (32) are each equipped with a web element (4) extending transversely to the first extension plane (14) and through the respective housing degassing opening (32), which divides the housing degassing opening (32) into two opening sections (42) and that the arrangement in the cell stack (33) is in the direction of the second extension plane (24), so that the forces arising from an operational swelling of the battery cells (3) and acting on the housing (2) are introduced into the web elements (4). [2] Battery device (1) according to the preceding claim, wherein the bridge elements (4) are firmly and integrally connected to the housing wall (22). [3] Battery device (1) according to one of the preceding claims, wherein the housing degassing openings (32) are each formed in the first extension plane (14) at least twice as long as in the second extension plane (24). [4] Battery device (1) according to one of the preceding claims, wherein the housing venting openings (32) are closed by means of at least one overpressure element (5) and wherein the overpressure element (5) is suitable and designed to at least partially release the housing venting opening (32) under pressure. [5] Battery device (1) according to the preceding claim, wherein at least the opening sections (42) belonging to each housing venting opening (32) are closed by a common overpressure element (5). [6] Battery device (1) according to one of the two preceding claims, wherein the overpressure element (5) is connected to the housing wall (22) in a material-bonded manner around the housing degassing opening (32) and wherein the overpressure element (5) is also connected to the web element (4) at least sectionally in such a manner or wherein the overpressure element (5) is not attached to the web element (4). [7] Battery device (1) according to one of the three preceding claims, wherein the overpressure element (5) is suitable and designed to detach at least partially from the housing wall (22) and / or bridge element (4) under pressure and / or to tear under pressure, and wherein the overpressure element (5) has at least one predetermined breaking point for this purpose. [8] Battery device (1) according to one of the preceding claims, wherein the web elements (4) are produced by selectively removing material in the area of ​​the opening sections (42) during the production of the housing degassing openings (32) and wherein the material removal is carried out by water jet cutting and / or laser beam cutting and / or a machining process. [9] Battery device (1) according to one of the preceding claims, wherein the housing degassing openings (32) are aligned at least partially in the direction of the second extension plane (24) and / or wherein the web elements (4) are arranged at least partially along a common longitudinal axis extending in the direction of the second extension plane (24). [10] Battery device (1) according to one of the preceding claims, wherein the housing (2) is a module housing (62) for a battery module (10) and wherein the battery device (1) comprises a plurality of battery modules (10).

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