Battery system

Abstract

The invention relates to a battery system (100) with a battery compartment (102) for receiving battery cells and / or battery modules, wherein an intermediate space (106) adjoins the underside of the battery compartment (102), extending between a battery compartment floor (104) and a subfloor section (108). At least one water drain nozzle in the form of a flap valve (110) with two abutting lips (112) is arranged in the battery compartment floor (104) and is designed such that, in the event of overpressure in the battery compartment (102) or an accumulation of liquid in the area of ​​the flap valve (110), fluids escape from the battery compartment (102) via the flap valve (110), and, in the event of overpressure in the intermediate space (106), an inflow of gas from the intermediate space (106) into the battery compartment (102) is prevented.

Description

[0001] The invention relates to a battery system with a battery compartment floor and an intermediate space extending beneath it, which is bounded on the underside by an underbody section, in particular a battery system of a motor vehicle. Liquids and gases escaping from the battery system are discharged in a controlled manner via this intermediate space, which can also be referred to as a bollard intrusion space or exhaust space. The underbody section is, in particular, a so-called curb guard, a flat element with which the battery system is protected from upward forces acting from below, which can occur, for example, when a vehicle drives up and down curbs.

[0002] For the sake of completeness, reference is also made to motor vehicles with a battery system described in this disclosure. The invention is also intended to extend to such motor vehicles.

[0003] From DE 10 2020 204 436 A1, a valve device and an electrochemical system are known by means of which both overpressure and underpressure can be balanced. One embodiment of the described valve devices has a slotted element 160, which can be considered a reed valve. This comprises two lip sections that approach each other in a funnel shape up to an outlet gap (slot). A specific arrangement of such a valve device in a battery system is not disclosed.

[0004] A valve device with a similar design is known from EP 1 892 029 A1. In this valve device as well, two lips approach each other in a funnel shape up to an outlet gap.

[0005] From DE 10 2021 132 479 A1, a battery arrangement and a method for removing a gas from a battery cell are known. The battery arrangement comprises a cooling wall arrangement, which includes a cooling wall, and at least one battery unit arranged on the cooling wall arrangement and positioned above the cooling wall arrangement with respect to a first direction, which comprises at least one battery cell.

[0006] The at least one battery cell has a first side with a releasable degassing opening, which can be opened to allow gas to escape from the at least one battery cell. The battery assembly includes a degassing channel into which, in the event of gas escaping from the degassing opening of the at least one battery cell, the escaping gas can be at least partially introduced. Furthermore, the battery unit is arranged on the cooling wall assembly such that the first side of the at least one battery cell faces the cooling wall assembly. The degassing channel is located below the releasable degassing opening and above the cooling wall with respect to the first direction and is designed such that, in the event of gas escaping from the degassing opening, a first portion of the gas escaping from the degassing opening can be introduced into the degassing channel.It is also revealed that the cooling wall can be designed as a cooling plate and may be equipped with an unspecified pressure relief valve or bursting element.

[0007] From DE 10 2021 123 314 A1, an electric vehicle with an electric drive unit is known, which has an underbody unit with a battery housing and several battery cells arranged in an interior space of the battery housing. The battery housing also has a degassing device, wherein the degassing device is said to have a pressure-opening valve or a bursting element, which is not described in more detail.

[0008] US patent 2021 / 0050573 A1 discloses a battery module, one embodiment of which also shows a reed valve with two abutting lips, intended as an alternative to a spring-loaded pressure relief valve. The reed valve is designed to allow degassing in the event of overpressure inside the battery module. A problem with this reed valve is that it can flip open towards the interior of the battery compartment when overpressure occurs outside the battery module.

[0009] The invention is based on the objective of providing a battery system with which fluids, in particular water and air, can pass from the battery compartment into the intermediate space as required, while simultaneously ensuring that no gases from the intermediate space enter the battery system when a gas overpressure arises in the intermediate space.

[0010] The problem is solved according to the invention by the features of the independent claims. Further practical embodiments and advantages of the invention are described in connection with the dependent claims.

[0011] The battery system according to the invention has a battery compartment for accommodating battery cells and / or battery modules, wherein an intermediate space adjoins the underside of the battery compartment – ​​in particular directly – which extends between a battery compartment floor and an underbody section. The underbody section can in particular be an underride guard for a battery compartment floor. Generally, the underbody section is preferably formed by two surfaces, each extending substantially horizontally.

[0012] At least one water drain nozzle in the form of a flap valve with two abutting lips is arranged in the battery compartment floor. For the purposes of this disclosure, "abutting lips" means both that the lips are in full contact with each other, so that no gap is formed at all, and that the distance between the lips, particularly due to manufacturing processes, does not exceed 1 mm. Preferably, the maximum distance between the abutting lips is 0.5 mm, more preferably 0.3 mm, and most preferably a maximum of 0.1 mm. In another particular embodiment, no gap is provided between the lips at all, so that they are in full contact with each other. Hereinafter, the terms "water drain nozzle" and "flap valve" are used synonymously unless expressly stated otherwise.

[0013] The reed valve is designed such that in the event of overpressure in the battery compartment or an accumulation of fluid in the area of ​​the reed valve, fluids escape from the battery compartment via the reed valve. In other words, the reed valve is designed so that the gap formed by the two lips is such that at least one initial drop of fluid is trapped in the reed valve, i.e., not allowed to pass through, and the reed valve only opens when several fluid drops have accumulated. Furthermore, the reed valve is preferably designed such that it opens wider as more fluid enters the area of ​​the reed valve. Thus, the drainage of fluids is reliably and easily achieved, preventing the fluid level in the battery compartment from reaching a level at which fluid damage is to be expected.

[0014] Furthermore, the reed valve is designed in such a way that, in the event of overpressure in the intermediate space, it prevents gas from flowing from the intermediate space into the battery compartment. This ensures that, in particular, no gases flow into the battery compartment from the intermediate space, which serves as a degassing chamber, during thermal events (especially thermal propagation) that can lead to a short-term pressure increase in the intermediate space.

[0015] In a battery system according to the invention, a grid structure or other support device is provided on the inlet side of the reed valve. The grid structure can be formed integrally with the base section, for example as holes in the base section, or it can be inserted into the opening as a separate element. Such a grid structure prevents larger particles or elements that might be present in the fluid from entering the reed valve, thus preventing clogging. Furthermore, the grid structure prevents the reed valve from being forced through the opening into the battery compartment under high back pressures that push it towards the battery compartment.

[0016] Alternatively or additionally, the arrangement of the battery compartment floor and the reed valve is designed in such a way that movement of the reed valve into the battery compartment is structurally prevented. This can be achieved in particular by making the opening provided in the battery compartment floor for inserting the reed valve so small that a flipping of the reed valve from the space into the battery compartment is technically impossible, even under the highest expected pressure in the space.

[0017] Preferably, the reed valve, and in particular its lips, comprises or is made of an elastic material. Non-limiting examples of such materials include, in particular, ethylene propylene diene monomer (EPDM) rubber, silicone, or common materials used for sealing rings known as "O-rings," such as rubber, neoprene, polytetrafluoroethylene (PTFE), or variants thereof. This allows for the simple manufacture of the reed valve (especially its lips). Through geometric designs that are relatively easy to adapt using the aforementioned materials, the reed valve can be tailored to specific requirements.

[0018] According to a practical embodiment, the two lips are arranged in abutting contact over a height of at least 2 mm, preferably at least 3 mm, and more preferably at least 4 mm or at least 5 mm, extending from an outlet-side slot. This design ensures a reliable (gas) seal of the reed valve, particularly when no liquid is present in the valve. At the same time, the discharge of liquid through the reed valve is not impaired, provided sufficient liquid accumulates in the valve.

[0019] Starting from a total height H of the flapper valve, the lips are arranged, according to an alternative embodiment, preferably at least over half the total height, i.e. 0.5*H, more preferably at least 0.7*H and particularly preferably at least over 0.8*H, or even over 0.9*H, in abutting each other.

[0020] In a practical embodiment, the lips are further connected to each other via at least one connecting section that acts as an opening limiter. In particular, the connecting section can be designed as a connecting web or as a connecting element. The connecting element is preferably formed in the area of ​​the slot, especially such that the slot is interrupted by the connecting element. This embodiment allows for good manufacturability as well as effective limiting action directly at the fluid outlet point of the flapper valve.

[0021] It can be advantageous if, according to a practical embodiment, the reed valve has a length extending in the direction of fluid flow that is greater than the height between the battery compartment floor and the underbody section. This can be achieved, in particular, by manufacturing it from an elastically deformable material and by using a curved shape. This results in a tube-like design, with the reed valve, in the form of the "tube," curving around the corner and also extending partially in the transverse direction between the floor section and the underbody section.

[0022] According to another practical embodiment, a funnel-shaped drain collar is formed in the reed valve and / or in the battery compartment floor. Liquid that enters the battery compartment and comes close to the reed valve is drawn by gravity towards the valve lips via this funnel-shaped drain collar. This design contributes to the advantageous gravity-driven drainage of liquid even from areas surrounding the reed valve inlet.

[0023] In another practical embodiment, the flapper valve is mounted in the battery compartment floor using a separate mounting ring. This mounting ring has, in particular, a plastic section or is made of plastic. Specifically, the mounting ring has a radially projecting collar to create an annular sealing surface.

[0024] According to an alternative, practical embodiment, the flap valve is bonded to the battery compartment floor. For this purpose, a contact surface is preferably formed in the flap valve, which serves as an adhesive surface and is brought into contact with the underside and / or the top side of the battery compartment floor. In this regard, particular reference is made to an annular or circumferential adhesive surface with a minimum circumferential width, especially with a minimum width of 2 mm, 3 mm, 4 mm or 5 mm.

[0025] The two embodiments described above allow the reed valve to be adapted to different battery systems and, in particular, to different battery bottoms, thus ensuring reliable drainage of liquid.

[0026] According to another practical embodiment, at least one vertically extending stabilizing structure is provided at each lip of the flapper valve. The stabilizing structure can preferably be formed or arranged on the flapper valve itself. In particular, the stabilizing structure is a stabilizing rib. Alternatively, the stabilizing structure can be a material thickening and / or attached struts or the like. An advantage of this embodiment is the reduction of fluttering noise and / or unwanted vibrations that could be caused by flapping of the lips.

[0027] In another practical embodiment, the outer dimension of the reed valve is at least 10 mm. The reed valve is preferably designed with a circular base. The reed valve can have a diameter from 10 mm to 100 mm, preferably 20 mm and particularly preferably 40 mm. Alternatively, the base of the reed valve can also be shaped differently, in particular oval, rectangular, or square.

[0028] Further practical embodiments of the invention are described below in connection with the drawings. They show: Fig. 1 a perspective view of part of a battery system with water drain nozzles in three different design variants; Fig. 2 a detailed representation of a water drain nozzle according to a first embodiment; Fig. 3 a half-section view of the in Fig. 2 shown embodiment of the water drain nozzle; Fig. 4 a detailed illustration of a water drain nozzle according to a further embodiment; and Fig. 5 a bottom view of the in Fig. 4 shown embodiment of the water drain nozzle.

[0029] In the figures, identical or at least functionally equivalent elements are always provided with the same reference symbols.

[0030] In Fig. Figure 1 shows part of a battery system 100 in a perspective view.

[0031] Furthermore, the battery system 100 has a battery compartment 102 for accommodating battery cells and / or battery modules (not shown). The battery compartment 102 is shown in Fig. Figure 1 shows only the battery compartment floor 104. Typically, the battery compartment 102 also has side walls and at least one top closure element, with which the battery compartment 102 can be sealed fluid-tight. It can also be a battery compartment 102 maintained at a slight overpressure or underpressure, through which a fluid, in particular air, constantly flows in order to keep the internal pressure in the battery compartment 102 as constant as possible. An intermediate space 106 adjoins the underside of the battery compartment 102. The intermediate space 106 extends between the battery compartment floor 104 and an underbody section 108. The underbody section 108 can, for example, be an underride guard of a motor vehicle.

[0032] At least one water drain nozzle in the form of a flap valve 110 is arranged in the battery compartment floor 104. Fig. Figure 1 shows three different embodiments of water drain nozzles by way of example, whereby in practice it is preferred to provide only water drain nozzles of a specific type or even only one water drain nozzle. In all embodiments, the water drain nozzle is designed as a flap valve 110.

[0033] The reed valve 110 has two abutting lips 112 (cf. Fig. 3 and Fig. 5) It is further designed such that, in the event of overpressure in battery compartment 102 or an accumulation of liquid in the area of ​​the reed valve 110, fluids can escape from battery compartment 102, preferably into the intermediate space 106, via the reed valve 110. Additionally, in the event of overpressure in the intermediate space 106, the inflow of gas from the intermediate space 106 into battery compartment 102 can be prevented. In other words, the reed valve 110 is fluid-permeable towards the intermediate space 106 and fluid-sealing towards battery compartment 102. Thus, liquids can be reliably drained from battery compartment 102 to prevent damage. At the same time, it prevents gases from flowing back into battery compartment 102 and damaging the battery system 100 there.

[0034] Furthermore, in Fig. 1. A funnel-shaped drain collar 113 is formed in the battery compartment floor 104. Liquid that enters the battery compartment 102 and comes near the reed valve 110 is conveyed by gravity towards the lips 112 of the reed valve 110 via the drain collar 113, if the installation position in the vehicle (not shown) is chosen such that gravity acts in the direction of arrow g.

[0035] In Fig. Figure 2 shows a detailed representation of a reed valve 110 according to a first embodiment.

[0036] The reed valve 110 already features the properties already mentioned in relation to Fig. 1 mentioned lips 112, which are in the Fig. 3 and Fig. Figure 5 illustrates this more clearly. Furthermore, the reed valve 110 has a mounting ring 114 with which the reed valve 110 is arranged on or in the battery compartment floor 104. Preferably, the reed valve 110 is inserted into the battery compartment floor 104 by means of the mounting ring 114 and positively locked in place. For this purpose, the mounting ring 114 has rigidly elastic locking elements 115 which are deflected elastically radially inwards when inserted and spring back radially after reaching the final mounting position, thus creating a releasable positive locking connection of the mounting ring 114.

[0037] The reed valve 110 also has a circular annular seal 116 designed as a sealing lip, which is arranged around the reed valve 110.

[0038] A cross-sectional view of the in Fig. The 2 shown reed valve 110 is in Fig. 3 shown. As in Fig. As can be seen in Figure 3, the reed valve 110 in this embodiment itself has a grid structure 118 which protects the reed valve 110 and in particular the lips 112 on the inlet side from the entry of particles or other “disturbing bodies” which could lead to damage or malfunction if they enter the reed valve 110.

[0039] What's next? Fig. As can be seen in Figure 3, an outlet-side slot 120 is formed between the lips 112 of the flapper valve 110. Furthermore, the lips 112 are connected to each other via at least one connecting section 122, which acts as an opening limiter.

[0040] Furthermore, the lips 112 preferably have or form a capillary geometry. This capillary geometry binds minute quantities of liquid. Incoming liquid pushes the existing liquid through the lips 112 and out of the flapper valve 110 on the outlet side. With larger quantities of liquid, the nozzle formed by the lips 112 can open further to increase the outflow of liquid.

[0041] Furthermore, the reed valve 110 has a stabilizing structure 124, which in the exemplary embodiment according to Fig. 3 is formed as an integral stabilizing rib. The stabilizing structure 124 serves to mechanically stabilize the lips 112. To direct the flow of liquid within the flapper valve 110, and particularly in the area of ​​the lips 112, to a specific position, the lips 112 have a drip nose 126 on their outlet side. This is understood to be the lowest point, viewed in the direction of gravity according to arrow g, to which liquid flows before dripping off due to gravity. This drip nose 126 extends only over a fraction of the length of the gap and is formed in this case at the connecting section 122. This is not strictly necessary, but advantageous, since the additional material required for the connecting section 122 also forms a drip nose.

[0042] Fig. Figure 4 shows another embodiment of the water drain nozzle 110 designed as a flapper valve. The in Fig. The embodiment shown in 4 is an alternative embodiment to the one shown in Fig. 2 and Fig. 3 embodiment shown.

[0043] Essentially, the design of the in Fig. 4 shown reed valve 110 of the embodiment of the reed valve 110, which is in the Fig. 2 and Fig. 3 is shown.

[0044] One difference, however, is that the reed valve 110 is bonded to the battery compartment floor 104. For this purpose, the reed valve 110 has an adhesive surface 128, which also serves, for example, as a seal 116. Furthermore, the aforementioned grid structure 118 is an alternative to the grid structure 118 in Fig. 2 and Fig. 3 in the battery room floor 104.

[0045] Moreover, the in Fig. 4. The embodiment of the reed valve 110 shown in relation to its function and construction is shown in the Fig. 2 and Fig. The embodiments of the reed valve 110 shown in the 3 examples are identical, so reference is made to their description in this respect.

[0046] A bottom view of the in Fig. The 4 shown reed valve 110 is in Fig. Figure 5 shows the flapper valve 110 being glued to a lower surface 130 of the battery compartment floor 104. Likewise, in Fig. Figure 5 shows the lips 112 and the drip nose 126 formed by the lips 112. Furthermore, in the exemplary embodiment according to Fig. 5 two stabilizing structures 124 which are integrally formed in the lips 112. The flutter valve 110, in particular the lips 112, have a length L by which the lips 112 extend into the space 106.

[0047] Moreover, the in Fig. 5 embodiment of the reed valve 110 shown with regard to function and construction with the ones in Fig. 2, Fig. 3 and Fig.The embodiments of the reed valve 110 shown in the 4 examples are identical, so reference is made to their description in this respect.

[0048] The features of the invention disclosed in the present description, the drawings, and the claims can be essential for realizing the invention in its various embodiments, both individually and in any combination. The invention can be varied within the scope of the claims and taking into account the knowledge of the person skilled in the art. Reference symbol list 100 battery system 102 Battery room 104 Battery compartment floor 106 space 108 Underbody section 110 reed valve 112 lips 113 Drainage collar 114 Mounting ring 115 Latching element 116 Seal 118 Lattice structure 120 slots 122 Connecting section 124 Stabilization structure 126 Droopy nose 128 adhesive surface 130 Underside of the battery compartment floor g arrow (direction of gravity) L Length of lips

Claims

[1] Battery system (100) with a battery compartment (102) for receiving battery cells and / or battery modules, wherein an intermediate space (106) is connected to the underside of the battery compartment (102), which extends between a battery compartment floor (104) and an underfloor section (108), characterized by, that at least one water drain nozzle in the form of a flap valve (110) with two abutting lips (112) is arranged in the battery compartment floor (104) and is designed such that, in the event of overpressure in the battery compartment (102) or in the event of an accumulation of liquid in the area of ​​the flap valve (110), fluids escape from the battery compartment (102) via the flap valve (110) and, in the event of overpressure in the intermediate space (106), an inflow of gas from the intermediate space (106) into the battery compartment (102) is prevented, wherein a grid structure (118) or other support device is provided on the inlet side of the flap valve (110) and / or the arrangement of battery compartment floor (104) and flap valve (110) is designed in such a way that movement of the flap valve into the battery compartment (104) is structurally prevented. [2] Battery system (100) according to the preceding claim, characterized bythat the two lips (112) are arranged abutting each other over a height of at least 2 mm, starting from an exit-side slot (120). [3] Battery system (100) according to any one of the preceding claims, characterized by , that the lips (112) are connected to each other via at least one connecting section (122) acting as an opening limit. [4] Battery system (100) according to any one of the preceding claims, characterized by , that the reed valve (110) has a length (L) extending in the direction of fluid flow which is greater than the height between the battery compartment floor (104) and the underbody section (108). [5] Battery system (100) according to any one of the preceding claims, characterized by, that a funnel-shaped drain collar (113) is formed in the reed valve (110) and / or in the battery compartment floor (104), over which liquid which comes into the vicinity of the reed valve (110) in the battery compartment (102) is conveyed by gravity towards the lips (112) of the reed valve (110). [6] Battery system (100) according to any one of the preceding claims, characterized by , that the reed valve (110) is mounted in the battery compartment floor (104) using a separate mounting ring (114). [7] Battery system (100) according to any one of claims 1 to 5, characterized by , that the reed valve (110) is glued to the battery compartment floor (104). [8] Battery system (100) according to any one of the preceding claims, characterized by , that at least one stabilizing structure (124) extending in a vertical direction is provided at each of the lips (112) of the flapper valve (110). [9] Battery system (100) according to any one of the preceding claims, characterized by , that the outer dimension of the reed valve (110) is at least 10 mm.

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