Traction battery for a vehicle

Abstract

Traction battery (20) of an electrically or partially electrically powered vehicle, wherein the battery is constructed from one or more interacting battery modules (1), in each of which chambers (3) are provided for accommodating one or more cell stacks (5) each comprising a plurality of battery cells, wherein the battery module (1) is designed as a hollow profile, each having a plurality of chambers (3) separated from one another by intermediate walls (10) and running parallel in the longitudinal direction of the hollow profile, into which the cell stacks (5) can be inserted, wherein the hollow profile is closed at both ends by a cover (2) each spanning the end-side opening cross-sections of all the chambers (3), and wherein the end sections (11) of the intermediate walls (10) extend up to the opening cross-section, characterized in that the end sections (11) of the intermediate walls (10) are sealed off from the inside of the cover (2) by a separate sealing component (7).

Description

FIELD OF INVENTION

[0001] The present invention relates to a traction battery for an electrically or partially electrically powered vehicle according to the preamble of claim 1. A battery system and a vehicle with such a traction battery are also disclosed. STATE OF THE ART

[0002] Traction or drive batteries for electrically powered vehicles often consist of a robust battery housing and several battery modules, which are either arranged within the housing or form the housing itself. The battery modules are electrically interconnected.

[0003] The term and object "battery module" is often defined differently in the prior art compared to the traction battery or energy storage device or accumulator as a whole, but always includes an assembly or a number of interconnected individual battery cells. Hereinafter, a traction or drive battery is defined as being constructed from battery modules, each of which forms a housing with chambers in which individual battery cells or cell stacks are arranged. The battery modules protect the battery cells or cell stacks not only from mechanical stresses, especially in the event of an accident, but also from environmental influences; they are designed to be watertight, gas-tight, and, importantly, fire-resistant.

[0004] The drive or traction batteries of electric vehicles store large amounts of energy through the numerous individual battery cells arranged in parallel or series. In electrochemical energy storage, electrons are stored in the individual battery cells via a chemical reaction during charging and released during discharge through a reverse chemical reaction. The reactants are usually separated from each other by a layer permeable only to electrons or ions, so they are not in direct contact. Modern systems incorporate so-called pouch cells as individual cells, in which the electrochemically active elements of a cell—planar electrodes and electrolytes—are sealed between films in the form of a pouch or cushion.Pouch cells in particular are generally sensitive to mechanical damage and therefore need to be protected by sturdy housings.

[0005] The reactants in the battery cells can, upon direct contact with each other, with ambient oxygen, with water or other substances, generate so much heat in a strong exothermic reaction that the battery cell or its components can ignite.

[0006] In the event of such a thermal event, i.e., overheating of cells, a large quantity of hot gas is produced, which must be vented from the cells and the battery system. Crucially, the gas must come into contact with surrounding battery cells or other cell compartments as little as possible to prevent or at least delay the ignition of further cells. If, in the case of high-performance traction batteries, gas flows from one cell stack compartment to another during a thermal event, this can lead to the ignition of the cells or cell stacks in the other compartment as well.

[0007] To prevent this, fire-retardant materials or partitions are often used between the individual cell stack compartments. Regulations for the protection of occupants in electric and hybrid vehicles stipulate that the spread of fires within a battery module housing or battery system housing must be locally contained and the spread to adjacent cell stacks must be prevented or at least delayed.

[0008] DE 10 2016 013 847 A1 discloses a battery housing for a motor vehicle battery, wherein the housing consists of several housing parts forming chambers which are provided with openings for the passage of connecting lines. The housing parts are screwed together with seals and a separate sealing surface carrier to seal the chambers against each other.

[0009] A generic traction battery for an electrically or partially electrically powered vehicle, in which the battery module is designed as a hollow profile, each having several chambers separated from one another by intermediate walls and running parallel in the longitudinal direction of the hollow profile, into which the cell stacks can be inserted, wherein the hollow profile is closed at both ends with a cover that overlaps the end opening cross-sections of all chambers and wherein the end sections of the intermediate walls extend to the opening cross-section, is known, for example, from DE 10 2017 127 807 A1.

[0010] DE 10 2012 221 694 A1 discloses a further embodiment of a traction battery. DESCRIPTION OF THE INVENTION

[0011] It is an object of the invention to provide a traction battery that is easy to manufacture, the battery modules of which are designed in such a way as to prevent or delay the ignition of cell stacks or individual cells in adjacent chambers as far as possible.

[0012] This problem is solved by the features of claim 1. Advantageous embodiments and further developments are described in the respective dependent claims. Also claimed are a battery system and an electrically or partially electrically powered vehicle with a traction battery according to the invention.

[0013] In the traction battery, the battery modules are designed as hollow profiles, each having several chambers separated from one another by partition walls and running parallel in the longitudinal direction of the hollow profile, into which the cell stacks can be inserted. The hollow profiles are closed at both ends with a cover that covers the end or front opening cross-sections of all chambers, and the end sections of the partition walls extending to the opening cross-section are sealed, according to the invention, with a separate sealing component towards the inside of the cover.

[0014] A separate sealing component, specifically designed to seal the gap between the partition walls and the lid, ensures a reliable seal between the chambers and thus a secure separation of the battery cells or cell stacks within their respective chambers. This prevents fire propagation between cell stacks in adjacent chambers, resulting in a significant improvement in vehicle safety.

[0015] An advantageous aspect of the invention is that the end cavities existing in the chambers of the hollow profile between the lid and the cell stack are sealed gas-tight to each other by the sealing component and to the outside by a further seal between the lid and the outer chamber walls. This design allows the sealing properties of the sealing component, on the one hand, and the circumferential seal to the outer chamber walls, on the other, to be specifically adapted to the respective requirements. Thus, the sealing component can be made of a different material than the circumferential seals and, in particular, can be designed such that compression of the sealing component between the lid and the partition prevents gas from flowing into the adjacent chamber.

[0016] According to a further aspect of the invention, the hollow profiles are designed as extruded profiles, preferably as individual sections cut off from a multi-length extruded profile. Extruded profiles are easy to manufacture and their cross-sections can be of any desired shape.

[0017] A further development of the invention consists in the fact that the chambers, separated by partition walls and running parallel in the longitudinal direction of the hollow profiles, have identical cross-sections. This also makes it possible to use the same profiles or cross-sections for the cell stacks in all chambers.

[0018] According to a further aspect of the invention, the cover spanning the chambers has at least one degassing opening or degassing element for each of the chambers, which are separated by partition walls and run parallel in the longitudinal direction of the hollow profile. Such a degassing opening or degassing element ensures that, in the event of gas formation, the gas escapes from the end cavities of the chambers in a controlled and as safe a manner as possible, particularly in a further embodiment of the traction battery, where the degassing opening or degassing element opens when a predetermined pressure is reached in the end cavity.

[0019] In the event that gaps form in the seals due to temperature changes or expansions, a further development of the invention provides that the flow cross-section that can be released for degassing through the degassing opening or the degassing element is larger than a gap cross-section remaining approximately to the sealing component between the end sections of the intermediate walls and the inside of the lid.

[0020] According to a further aspect of the invention, the sealing component is made of an elastomeric material, preferably rubber or a silicone plastic. This design provides, on the one hand, high elasticity of the seals and, on the other hand, high temperature resistance when heated.

[0021] A traction battery with the battery modules designed according to the invention is particularly suitable for a battery system in which several individually sealed and spaced-apart battery modules are provided. Such a battery system can be particularly well adapted to the cavities or installation situations present in a vehicle.

[0022] One embodiment of an electrically or partially electrically powered vehicle with a traction battery according to the invention consists in several battery modules, with their longitudinal axis lying transversely to the longitudinal axis of the vehicle, being arranged one behind the other in the longitudinal direction of the vehicle.

[0023] Such an arrangement, particularly when the battery modules are designed so that their respective chamber covers extend into the area of ​​the vehicle's sills, results in exceptionally good accessibility to the individual components of the traction battery without compromising safety. The traction battery, or rather the individual battery modules, would then be accessible from the vehicle's exterior and underside, allowing for easy repairs or the installation of new cell stacks. Replacing the battery modules would also be straightforward. With this design, where the modules extend across the vehicle's width, the battery modules are packed particularly densely, resulting in a compact traction battery.

[0024] The invention will now be described with reference to the exemplary embodiment shown in the figures of the drawing. Fig. 1. The basic design of a battery module in the form of a perspective sketch, Fig. 2 an end section of a battery module according to Fig. 1, Fig. 3 a sectional view of a battery module according to Fig. 1, Fig. 4 A sketch of a battery consisting of several battery modules arranged one behind the other in the longitudinal direction of the vehicle.

[0025] The figures may contain identical or similar elements referenced by the same reference symbols.

[0026] Fig. Figures 1 to 4 should be considered together in order to best understand the inventive design of the traction battery with its battery modules. Fig. Figure 1 shows, in the form of a perspective sketch, the basic design of a battery module 1 with its two single-sided covers 2 and its outer walls 9. A multitude of such battery modules 1 form a traction battery 20 in an electrically or partially electrically powered vehicle. Such a traction battery 20 is, in principle, in the Fig. Figure 4 shows the vehicle itself. The vehicle itself is not shown.

[0027] As in Fig. As sketched in Figure 4, the battery 20 is composed of several interacting battery modules 1 whose longitudinal axis is oriented transversely to the vehicle's longitudinal direction 21, and which are arranged one behind the other in the vehicle's longitudinal direction 21. The length of each battery module 1 is such that it extends approximately over the vehicle's width 23 and that the covers 2, which close the compartments 3 of the battery modules on both sides, reach into the area of ​​the body sills 22.

[0028] Fig. Figure 2 shows, in principle, an end section 4 of a battery module 1, the top of which is cut off to allow a view into the interior of the battery module. The arrangement of the cell stack 5 located in the chambers 3 of the battery module 1, which is designed as a hollow profile, can be seen. The design of the covers 2 and the end cavities 6 is also visible. Furthermore, an embodiment of the sealing component 7 and the additional external seals 8 between the cover 2 and the outer chamber walls 9 are shown, i.e., the seals 8 between the cover and the walls of the battery module.

[0029] The battery module 1 is designed as a hollow profile with two chambers 3, which are separated by an intermediate wall 10 and run parallel to each other in the longitudinal direction of the hollow profile. Cell stacks 5 are inserted into the chambers 3. The hollow profile, or battery module 1, is closed at both ends by a cover 2 that overlaps the end opening cross-sections of the battery module and the chambers 3, respectively. The end sections 11 of the intermediate walls 10, extending to the opening cross-section, are sealed to the inside of the cover 2 by a separate sealing component 7.

[0030] How best to view the section in Fig. As can be seen in Figure 3, the hollow profile or battery module 1 consists of a rectangular hollow profile with two parallel chambers 3, separated from each other by a right-angled partition 10. The hollow profile is an extruded profile, which was originally manufactured as a multiple length and then cut into individual lengths that essentially correspond to the length of the battery module, taking into account the necessary post-processing and any attachments mounted on it. Fig. 3 one can also see the contact tabs 12, which connect the individual battery cells of the cell stacks 5 to each other.

[0031] In summary, the Fig. 1, Fig. 2 and Fig. Figure 3 shows that the end cavities 6 of the chambers 3 of the battery module 1, located between the cover 2 and the cell stacks 5, are sealed gas-tight to each other by the sealing component 7 and to the outside by a circumferential seal 8 between the cover 2 and the outer chamber walls 9. The sealing component 7 is made of highly heat-resistant silicone plastic.

[0032] In Fig. 1 and Fig. Figure 2 further shows that each of the lids 2 spanning the chambers 3 has a degassing opening 13, in which a degassing element 13a, e.g. a bursting element, is formed for each of the chambers 3 separated by partition walls. The degassing element opens when a predetermined pressure is reached in the end cavity 6. List of reference symbols (part of the description) 1 battery module 2 lids 3 chambers in one battery module 4 End section of a battery module 5 cell stack 6 End cavity of the chamber 7 Sealing component 8 Seal between lid and outer chamber wall 9 outer chamber wall, outer wall of the battery module 10 Partition wall between the chambers 11 End section of the partition wall 12 contact flag 13 Degassing opening 13a Degassing element 20 traction batteries 21 Vehicle longitudinal direction 22 Body sills 23 vehicle width

Claims

[1] Traction battery (20) of an electrically or partially electrically powered vehicle, wherein the battery is composed of one or more interacting battery modules (1) in each of which chambers (3) are provided for receiving one or more cell stacks (5) of several battery cells each, wherein the battery module (1) is designed as a hollow profile which has several chambers (3) separated from one another by intermediate walls (10) and extending parallel in the longitudinal direction of the hollow profile, into which the cell stacks (5) can be inserted, wherein the hollow profile is closed at both ends with a cover (2) which overlaps the end opening cross-sections of all chambers (3) and wherein the end sections (11) of the intermediate walls (10) extend to the opening cross-section, characterized by , that the end sections (11) of the partition walls (10) are sealed to the inside of the lid (2) with a separate sealing component (7). [2] Traction battery (20) according to claim 1, in which end cavities (6) existing in the chambers (3) of the hollow profile between the cover (2) and the cell stacks (5) are sealed gas-tight to each other by the sealing component (7) and to the outside by a further seal (8) between the cover (2) and the outer chamber walls (9). [3] Traction battery (20) according to claim 1 or 2, wherein the hollow profile is formed as an extrusion profile, preferably as a separated single length of an extrusion profile produced in multiple lengths. [4] Traction battery (20) according to one of claims 1 to 3, wherein the chambers (3) separated by intermediate walls (10) and running parallel in the longitudinal direction of the hollow profile have identical cross-sections. [5] Traction battery (20) according to one of claims 1 to 4, in which at least one degassing opening (13) and / or one degassing element (13a) is formed in the cover (2) spanning the chambers (3) for each of the chambers (3) separated by intermediate walls (10) and running parallel in the longitudinal direction of the hollow profile. [6] Traction battery (20) according to claim 5, wherein the degassing opening (13) or the degassing element (13a) opens when a predetermined pressure is reached in the end cavity (6). [7] Traction battery (20) according to claim 5 or 6, wherein the flow cross-section that can be released for degassing through the degassing opening (13) or the degassing element (13a) is larger than a gap cross-section remaining approximately to the sealing component between the end sections (11) of the partition walls (10) and the inside of the cover (2). [8] Traction battery (20) according to any one of claims 1 to 7, wherein the sealing component (7) is made of an elastomeric material, preferably rubber or silicone plastic. [9] Battery system with a traction battery (20) according to claims 1 to 8, in which several individually sealed and spaced-apart battery modules (1) are provided. [10] Electrically or partially electrically powered vehicle with a traction battery (20) according to one of claims 1 to 8, in which several battery modules (1) lying with their longitudinal axis transverse to the longitudinal direction of the vehicle (21) are arranged one behind the other in the longitudinal direction of the vehicle (21). [11] Vehicle according to claim 10, wherein the length of the battery modules (1) is designed such that the covers (2) closing the chambers (3) on both sides extend into the area of ​​the body sills (22).

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