Battery for an electric drive of a motor vehicle as well as motor vehicles

Abstract

Battery (B) for an electric drive of a motor vehicle, comprising a plurality of battery modules (1) arranged one above the other in respective positions (2, 3, 4, 5), each of the superimposed positions (2, 3, 4, 5) of the battery modules (1) being received in a separate, assigned battery housing (8), which are arranged one above the other in a stack (13) and connected to each other, wherein the respective battery module (1) received in the respective assigned battery housing (8) is connected to this assigned battery housing (8) and to the battery housing (8) arranged below it via at least one connecting element (35), characterized in that the respective battery housing (8) is designed as a double shell with a base element (9) and a cover element (10), and that the respective battery module (1) is connected via the connecting element (35) to a cover plate (33) of the battery housing (8) arranged below it.wherein the connecting element (35) comprises a sleeve (36) which penetrates the respective battery module (1) in the upward direction of the battery (B) near an end face (41).

Description

[0001] The invention relates to a battery for an electric drive of a motor vehicle according to patent claim 1. Furthermore, the invention relates to a motor vehicle with such a battery.

[0002] The vast majority of batteries for electric drive systems in motor vehicles are now installed under the floor of the passenger compartment. Examples of such installation methods can be found in DE 10 2012 015 919 A1 and DE 10 2015 014 033 A1, in which battery modules, each of which comprises a plurality of interconnected battery cells, are arranged in a single layer or plane and housed in a battery housing. These known designs are extremely expensive, not least because of the required active cooling with a coolant. Furthermore, the considerable dimensions of the battery impose limitations on the design and manufacturing technology, as the battery housings are typically relatively difficult to seal.

[0003] US 2013 / 0 330 587 A1 discloses a vehicle battery unit in which the support and end plates of the second battery module are placed on top of those of the first battery module, preventing the weight of the second module from acting on the battery cells of the first module. This eliminates the need for additional support elements and allows the dimensions of the first module to be reduced. It is disclosed that long screws and the respective plates of the battery modules are guided to create a screwed connection.

[0004] A battery of this type is already known from DE 10 2013 106 433 A1, in which two battery modules, each of which typically contains a plurality of interconnected battery cells, are arranged one above the other in different positions in the vertical direction of the vehicle. The two battery modules are housed in a common battery housing, which extends across the height of both layers of battery modules. A stiffening element, for example in the form of a horizontal intermediate plate or intermediate plane, also runs between the two battery modules. This stiffening element connects the respective, opposing housing parts to one another and is intended to promote the block formation of the battery housing in the event of an impact in the front of the vehicle.

[0005] US 2008 / 0050645 A1 already discloses a battery comprising a plurality of battery modules arranged in an associated layer and housed in an associated battery housing. Two such battery housings are arranged one above the other and connected to each other via screw elements. The battery modules are connected to strips via screws. These strips, in turn, have tabs attached to them, by means of which the strips can be clamped between flanges of a cover element and a base element with the aid of additional screw elements.

[0006] US 2013 / 0316212 A1 discloses a battery container in which a plurality of battery modules are arranged in a single layer and housed in a battery subcontainer. Several battery subcontainers are stacked one above the other and held by a base plate and between lateral fixing plates.

[0007] The object of the present invention is to provide a battery and a motor vehicle with such a battery, which has improved accident characteristics and, moreover, is easy to manufacture.

[0008] This object is achieved according to the invention by a battery and a motor vehicle with such a battery according to patent claims 1 and 7. Advantageous embodiments with favorable further developments of the invention are the subject of the dependent claims.

[0009] The present battery is characterized by a plurality of battery modules, each comprising a plurality of interconnected battery cells, arranged one above the other in at least two layers in the vertical direction of the vehicle. This arrangement enables a space-saving design of the battery, allowing it to be installed particularly, but not exclusively, in the front of the vehicle or in the area of ​​the front-end structure / crumple zone of the vehicle.

[0010] It is provided that each of the superimposed layers of battery modules is accommodated in a respective, separate battery housing, which are arranged one above the other in a stack and connected to one another. This offers the considerable advantage that such a battery housing can be manufactured extremely cost-effectively, as it is much smaller. Each of these battery housings can preferably be designed at least substantially as an identical part, which significantly simplifies production. The number of battery housings used in each case, which corresponds to the number of layers of battery modules, can then be arranged one above the other in a stack, with the adjacent battery housings being connected to one another, for example, via corresponding connecting elements.The particular advantage of this simple design of the respective battery housings lies not only in their ease of manufacture, but also in the correspondingly simple possibility of achieving the required tightness and, due to the greater variability in the arrangement of the battery housings on top of each other, also in terms of crash performance. The stack of battery housings can be designed to be extremely shear-resistant by appropriate measures.

[0011] According to the invention, the battery housings are connected in that the respective battery module, which is arranged within the associated battery housing, is connected to said battery housing and the battery housing arranged underneath it via at least one connecting element. In other words, the respective connecting element not only serves to fix the corresponding battery module within the associated battery housing, but by means of the connecting element, said battery housing is also connected to the battery housing underneath it - or corresponding individual parts (base element and cover element) thereof. In this case, preferably several, for example two or four, connecting elements can be used per battery module, on the one hand to fix the battery module and on the other hand to connect the battery housings or their individual parts (base element and cover element) to one another.

[0012] This means that twice the wall thickness of two battery housings can be used to screw the modules together. The bracing of the respective battery housings or parts thereof results in very high performance in the event of an accident-related force being applied, as the entire system is braced and shear fields are formed which optimally transfer the forces. This means that the high accelerations of over 90 g in a rear-end impact, for example, can be dampened and dissipated by the bracing without the respective battery housing being destroyed in the area of ​​the connecting element. In addition, the connection of the two battery housings arranged one above the other or their respective components results in further cost advantages, as the base of a protective housing, for example, can be made smaller. In addition, the connection technology between the base and the stack of battery housings can then be simpler.

[0013] The battery can be used in both a purely electric vehicle and a hybrid vehicle. In some cases, multiple batteries can be installed within the vehicle for propulsion.

[0014] It is also provided that the respective battery housing is designed as a double shell with a base element and a cover element. This not only enables a simple construction and simple manufacture of the battery housing, but also an easy connection of the base element of one battery housing to the cover element of the additional battery housing arranged underneath it via the at least one connecting element, by means of which the correspondingly assigned battery module is also connected to the two battery housings or their base / cover elements. It is provided that the connecting element comprises a sleeve which passes through the respective battery module in the vertical direction of the battery near one end face.

[0015] A particularly simple and equally shear-resistant connection can also be achieved if the respective battery module is connected via the connecting element to a cover plate of the battery housing arranged underneath or its cover element.

[0016] In addition, a particularly shear-resistant connection of the stack of battery housings results if the base element accommodating the respective battery module is clamped via the connecting element between the respective battery module and the cover element of the battery housing arranged underneath. For this purpose, in a further advantageous embodiment of the invention, a support element, in particular a dome element, is integrated into the base plate of the base element accommodating the respective battery module, via which support element the base element is clamped between the respective battery module and the cover element of the battery housing arranged underneath. Such a support element or dome element serves as a centering aid during assembly of the stack of battery housings in its vertical direction, which in this case also corresponds to the vertical direction of the vehicle.

[0017] A further advantageous embodiment of the invention provides that the respective battery housing is formed from a plastic, in particular a fiber-reinforced plastic. A battery housing made of such a plastic is not only cost-effective and easy to produce, but moreover, corresponding functional elements for stiffening, for connection to other components, or the like can also be easily molded onto it. It is particularly advantageous if at least a number of the stacked battery housings are - at least essentially - identical in shape. "Identical in shape" is to be understood in particular as meaning that all battery housings or their respective components can be manufactured in the same mold, for example, an injection mold. This can significantly reduce the cost of the battery due to the identical parts.

[0018] In a further embodiment of the invention, a screw sleeve or similar retaining element of the connecting element is integrated into the cover element. This can be achieved in a particularly simple manner if the cover element is made of a plastic.

[0019] Furthermore, in a further embodiment of the invention, it is advantageous if a clearance is provided between the underside of the battery module and the base plate of the base element that accommodates the battery module. This effectively prevents a double fit and connects the base element located above it to the cover element of the associated battery housing located below it.

[0020] Preferably, the stack of battery housings is surrounded by a protective housing for the battery. This protective housing does not have to be closed, as it preferably has no sealing function, but can also be partially open. Since such a sealing function is preferably not required, the protective housing can be designed accordingly simply and, in particular, optimized with regard to the stability and rigidity of the battery, particularly with regard to its accident behavior. For this purpose, the protective housing can be formed at least partially by corresponding side walls or similar elements which have a corresponding absorption capacity for accident energy. In an alternative embodiment, however, it would theoretically also be conceivable to design such a protective housing to be sealed.

[0021] The advantages described above in connection with the battery according to the invention also apply to the motor vehicle according to the invention according to patent claim 7.

[0022] Exemplary embodiments of the invention are described below. Shown are: Fig. 1 is a perspective exploded view of the essential components of the battery according to the invention according to an advantageous embodiment, Fig. 2 a schematic and partial sectional view of the battery installed in the front of a motor vehicle according to an advantageous embodiment, Fig. 3 a perspective view of a base element and a cover element of a battery housing of the battery according to the invention, Fig. 4 respective perspective views of the battery according to an advantageous embodiment, in which a plurality of battery housings, in each of which a plurality of battery modules are accommodated, are arranged one above the other in a stack and connected to one another, Fig. 5 a sectional view through the stack of battery housings arranged one above the other of the battery according to the advantageous embodiment, Fig. 6 is a partial and enlarged schematic sectional view of a base element and a cover element of battery housings arranged one above the other, each of the components comprising respective plug-in connection elements, via which the adjacent battery housings can be positioned relative to one another and mutually supported in the pushing direction, Fig. 7 a partial and enlarged sectional view of respective, mutually adjacent battery housings in the region of a connecting element, by means of which, on the one hand, a battery module can be fixed within the associated battery housing and, on the other hand, the battery housing can be connected to the adjacent battery housing arranged underneath, Fig. 8 is a perspective view of a base plate of a protective housing of the stack of battery housings, in the corner area of ​​which respective tie rods are provided for holding the stack of battery housings or the protective housing, Fig. 9 a perspective view and a sectional view of the protective housing within which the stack of battery housings is accommodated.

[0023] The exemplary embodiments explained below are preferred embodiments of the invention. In the exemplary embodiments, the described components of the embodiments each represent individual, independently considered features of the invention, which also further develop the invention independently of one another and are thus also to be considered as components of the invention, either individually or in a combination other than that shown. Furthermore, the described embodiments can also be supplemented by further features of the invention already described.

[0024] In the figures, functionally identical elements are provided with the same reference numerals.

[0025] In Fig. 1, a perspective exploded view of the essential components of a battery B can be seen, which is additionally shown assembled in a schematic perspective view on the right. The battery B initially comprises a plurality of battery modules 1, of which in the present case, for example, four are arranged next to one another in a horizontal plane or in the vertical direction of the vehicle at a common height in a corresponding layer 2, 3, 4, 5. In other words, in the present case, four battery modules 1 are arranged at the same height or within a corresponding layer 2, 3, 4, 5, wherein the majority of these layers 2, 3, 4, 5 are arranged one above the other in a manner described in more detail below. Each battery module 1 is formed by a plurality of battery cells connected to one another in parallel and / or in series.The output voltage of each battery module 1 is therefore correspondingly greater than the output voltage of the respective plurality of associated battery cells. The output voltage of the entire battery B is therefore greater than that of the respective battery modules 1, which are interconnected accordingly.

[0026] Furthermore, the battery B comprises a cooling device 6, described in more detail below, within which a coolant circulates. The cooling device 6 comprises a plurality of flat cooling elements or cooling lines 7, four of which run on a common plane or in one plane. The cooling elements or cooling lines 7 run, in a manner described in more detail below, on the underside of the associated battery module 1 or on the underside of the respective layer 2, 3, 4, 5 of battery modules 1.

[0027] The respective layer 2, 3, 4, 5 of battery modules 1 is accommodated within a respective associated battery housing 8, as one of them in Fig. 3 in a respective perspective view of a base element 9 and a cover element 10 of the battery housing 8. The base element 9 and the associated cover element 10 are closed after being equipped with the respective four battery modules 1 of the corresponding layer 2, 3, 4, 5 in the area of ​​respective, mutually associated flanges 11, 12 by means of a seal (not further visible). Since in the present case four layers 2, 3, 4, 5 of battery modules 1 are provided, accordingly four battery housings 8 are provided in a Fig. 1 are arranged one above the other in a stack 13. The respective battery housings 8 are positioned relative to one another and connected to one another in a manner described below.

[0028] The stack 13 of the battery housings 8 with the cooling device 6 is accommodated in a protective housing 14, which is Fig. 1 is also shown exploded. This protective housing 14 comprises a base 15 and four side walls 16, which in this case are each composed of two parts or layers 17 and 18. In the present case, these two parts are, for example, a corrugated sheet 17 and an associated locking plate 18, in order to achieve a multi-layer component that absorbs energy well. In addition, the protective housing 14 comprises a cover 19, so that the stack of battery housings 8 is completely enclosed by the protective housing 14 in this case. The protective housing 14 is also referred to as a crash shield and is in Fig. 1 on the right can be seen again in assembled form in a corresponding perspective view.

[0029] Fig. Figure 2 shows a schematic sectional view of a front end 21 arranged in front of a passenger compartment, or rather, a front end structure / crumple zone of a passenger car, in the area of ​​which the battery B is arranged. The battery B is held at the level above a front axle 20 of the vehicle in a manner not otherwise recognizable to corresponding components of the body or to subframe elements that are attached to the body on the body shell side. The battery B is integrated into the vehicle's crash systems.

[0030] Out of Fig. 2, it becomes particularly clear that the battery B installed in the front end 21, thanks to its excellent positioning, can be installed analogously to an internal combustion engine or instead of it. The high structure of the battery B with the multiple layers 2, 3, 4, 5 of battery modules 1 in the corresponding battery housings 8 and their arrangement one above the other to form the stack 13 results in the possibility of optimally utilizing the installation space required by the internal combustion engine in motor vehicles. The protective housing 14 optimally protects the stack 13 of battery housings 8.

[0031] The respective battery housing 8 or its individual parts, in this case the base element 9 and the cover element 10, are formed from a plastic, in particular a fiber-reinforced plastic, and are manufactured, for example, by an injection molding process. The use of plastic not only has the advantage of simple and cost-effective production of the identically shaped battery housing 8, but also allows functional elements such as elements / ribs of a stiffening structure 23 and / or plug-in connection elements 34 ( Fig. 6) for connecting the battery housing 8 to the adjacent battery housing 8. Furthermore, plastic is particularly suitable for integrating reinforcing elements such as inserts, screw sleeves, or the like, or even functional elements of the cooling device 6, into the respective battery housing 8.

[0032] The stiffening structure 23 with the ribs is designed specifically for load cases involving accidental force application. The flanges 11, 12 of the base and cover elements 9, 10, for example, are formed in standard geometry and connected to each other via screws.

[0033] Furthermore, Fig. 3 that corresponding compartments within the base and cover elements 9, 10 are divided by respective webs 25, within which the respective battery modules 1 are accommodated.

[0034] Fig. 4 shows, in two respective perspective views, the plurality of, in this case, four battery housings 8, in each of which the plurality of battery modules 1 are accommodated and which are arranged one above the other in the stack 13 and connected to one another. Furthermore, the partial integration of the cooling device 6 into the stack 13 of battery housings 8 can be seen here. The flat cooling lines or cooling elements 7 are arranged on the underside of the respective battery housing 8 or between two adjacent battery housings 8, respectively. The individual cooling elements 7 are connected via supply lines 26, which in this case run, for example, in the corner region of the stack 13. The supply lines 26, designed as risers, have throttles in this case. Furthermore, the plug connections between the components of the cooling device 6 are optimized with regard to flow resistance.

[0035] On its rear side, the stack 13 of battery housings 8 has a continuous channel 27 which connects the interior of the respective battery housings 8. This channel is formed by a Fig. 3, a shaped end wall 28 is formed in the base and cover element 9, 10 of the respective battery housing 8, wherein a through opening 29 is also formed in the respective base and cover element 9, 10, via which the channel 27 is formed.

[0036] In order for the entire stack 13 of battery housings 8 to be sealed, as can be seen from the sectional view through the stack 13 according to Fig. 5, a seal 31 is provided between the edge region 30 of the through-opening 29 of one battery housing 8 and the edge region 30 of the through-opening 29 of the adjacent battery housing 8. This seal 31 can, for example, be formed by a screw-in or plug-in sleeve through the respective through-openings 29 or by a seal which is inserted between the battery housings 8. In any case, the aim is to ensure that the edge region 30 of the through-opening 29 of one battery housing 8 is sealed with the seal 31 against the edge region 30 of the through-opening 29 of the adjacent battery housing 8.

[0037] In particular, the respective layers 2, 3, 4, 5 of battery modules 1 are interconnected via the channel 27. For example, a strip-like or rod-like conductor can run within the channel 27. Unused feedthrough openings 29, for example, on the underside of the lowest or on the top side of the uppermost battery housing 8 of the stack 13, can be closed, for example, by a plug.

[0038] Fig. 6 shows a partial and enlarged, schematic sectional view of the base element 9 of one of the battery housings 8, which rests with a base plate 32 on a cover plate 33 of the battery housing 8 arranged underneath. Plug connection elements 34, indicated by way of example, project downwards from the base plate 32 and interact with further plug connection elements 34 projecting upwards from the cover plate 33 in such a way that the adjacent battery housings 8 are connected and positioned relative to one another. This can, for example, greatly facilitate the assembly of the stack 13 of battery housings 8. In addition, forces, in particular shear forces, can be transmitted between the adjacent battery housings 8 via the plug connection elements 34 in the event of an accident-related force being applied.The shear-resistant connection of the battery housings 8 can thus significantly improve the rigidity of the battery B. The plug-in connection elements 34 can be, for example, latches, blockers, domes, clips, or the like.

[0039] In Fig. 7 shows a partial and enlarged sectional view of two adjacent battery housings 8 in the region of a connecting element 35. The connecting element 35 comprises a sleeve 36 which extends through the respective battery module 1 near an end face 41 in the vertical direction of the battery B, which also corresponds to the vertical direction of the vehicle. In the present case, two connecting elements 35 are provided per end face 41 of each battery module 1, thus in the present case a total of four connecting elements 35 per battery module 1 and 32 connecting elements 35 per layer 2, 3, 4, 5 of battery modules 1. However, it is clear that this number can vary depending on the design, which depends, for example, on the number of layers 2, 3, 4, 5 or the size of the individual battery housing 8.

[0040] A screw element (not shown) extends within the sleeve 36, the head of which rests on a plate 37 of the battery module 1 on top of the sleeve 36, which plate is firmly connected to the sleeve 36. On the underside, the sleeve 36 or the battery module 1 rests on a support part in the form of a dome part 38, which is received in a similarly shaped receptacle 42 in the plastic of the base plate 32 of the base element 9.

[0041] Adjoining the bottom is a screw sleeve 39, which is firmly integrated into the plastic of the cover plate 33 of the cover element 10, or in this case, injected into it. The above-described screw element is screwed into the underside of said screw sleeve 39. When the screw element is tightened, the battery module 1 is clamped downward against the base element 9 and against the dome part 38, which in turn is supported on the cover plate 33 of the cover element 10 of the underlying battery housing 8. The cover element 10 and the battery module 1 are centered and fixed relative to the cover plate 33 of the cover element 10 of the underlying battery housing 8 by means of the dome part 38.

[0042] To avoid a double fit, a free space 43 is provided between an underside 44 of the battery module 1 and the base plate 32 of the base element 9 of the battery housing 8 accommodating the respective battery module 1, which is filled, for example, with a filler made of a plastic material. By tightening the screw element, the battery module 1 is thus connected or clamped to the base element 9 and also to the cover element 10. Since in this case two connecting elements 35 are provided for each end face 41 of each battery module 1, i.e. in this case a total of four connecting elements 35 per battery module 1 and 16 connecting elements 35 per layer 2, 3, 4, 5 of battery modules 1, this results in an overall clamping of the respective battery housing 8 or the associated base / cover elements 9, 10, which have a very high performance in the event of an accident-related force being applied.Because the entire system is braced and shear fields are formed, the forces can be optimally transmitted. For example, the high accelerations of over 90 g during a rear-end impact can be dampened and dissipated by the bracing without the respective battery housing 8 being destroyed in the area of ​​the connecting element 35. Furthermore, the connection of the two battery housings 8 arranged one above the other, or their respective components, results in further cost advantages, since, for example, the base 15 of a protective housing 14 can be made smaller. Furthermore, the connection technology between the base and the stack of battery housings 8 can then be simpler.

[0043] Fig. 8 shows a perspective view of the base plate or the floor 15 of the protective housing 14, by means of which the stack 13 of battery housings 8 is enclosed. In the corner areas of the base plate 15, respective tie rods 40 extending in the vertical direction of the vehicle are provided for holding the stack 13 of battery housings 8 or the protective housing 14. The tie rods 40 can also be used for installing or removing the battery B, for example, by screwing crane loops onto the top. Thus, the battery B, including its protective housing 14, can be removed from or installed in the motor vehicle.

[0044] In addition, the base plate 15 has respective screw sleeves 39 or threaded holes integrated therein, which are used in connection with Fig. 7 described functions for holding the floor element 9 arranged above it or the battery modules 1 accommodated by its battery housing 8.

[0045] Finally, Fig. 9 shows a perspective view and a sectional view of the protective housing 14, within which the stack 13 of battery housings 8 is accommodated. Particularly visible are the four side walls 16, which in this case are formed from the internally arranged corrugated sheet 17 and the externally arranged, flat locking plate 18, thus forming the highly energy-absorbing, multi-layer component. Also visible is the cover 19 of the protective housing 14. Like the base 15, this cover is also formed, for example, from a metal material such as sheet metal.

[0046] The side walls 16 or their respective components 17, 18 are made of aluminum or steel alloy-based sheets and are mitred together, for example, in the corners. Strips or the like can also be used in the corners as load distributors. For pre-assembly, the side walls 16 can be pre-attached to the stack 13 of battery housings 8, in particular to non-recognizable fastening elements, such as locking pins or the like, which are molded or arranged in the plastic of the respective battery housing 8. This allows the side walls 16 and, if applicable, also the cover 19 to be first attached to the stack 13 and then connected to one another. By means of the method described in connection with Fig.The components 15, 16, and 19 of the protective housing 14 can be additionally clamped together using the tie rods 40 already described. The battery housings 8 arranged one above the other in the stack 13 can also be clamped together using the tie rods 40.

[0047] It is clear that the protective housing 14 can also be formed with other plate elements made of a variety of materials and in different designs.

Claims

[1] Battery (B) for an electric drive of a motor vehicle, comprising a plurality of battery modules (1) which are arranged one above the other in respective layers (2, 3, 4, 5), and each of the layers (2, 3, 4, 5) of the battery modules (1) arranged one above the other is accommodated in a respective, separate battery housing (8), which are arranged one above the other in a stack (13) and connected to one another, wherein the respective battery module (1) which is accommodated in the respective associated battery housing (8) is connected via at least one connecting element (35) to the battery housing (8) associated therewith and to the battery housing (8) arranged thereunder, characterized bythat the respective battery housing (8) is designed as a double shell with a base element (9) and a cover element (10), and that the respective battery module (1) is connected via the connecting element (35) to a cover plate (33) of the battery housing (8) arranged underneath, wherein the connecting element (35) comprises a sleeve (36) which passes through the respective battery module (1) in the vertical direction of the battery (B) near an end face (41). [2] Battery (B) according to claim 1, wherein the base element (9) receiving the respective battery module (1) is clamped via the connecting element (35) between the respective battery module (1) and the cover element (10) of the battery housing (8) arranged thereunder. [3] Battery (B) according to claim 2, wherein a support element, in particular a dome part (38), is integrated in a base plate (32) of the base element (9) receiving the respective battery module (1), by means of which support element the base element (9) is clamped between the respective battery module (1) and the cover element (10) of the battery housing (8) arranged thereunder. [4] Battery (B) according to one of the preceding claims, wherein the respective battery housing (8) is formed from a plastic, in particular a fiber-reinforced plastic, [5] Battery (B) according to one of claims 2 to 4, wherein a screw sleeve (39) or similar holding element of the connecting element (35) is integrated into the cover element (10). [6] Battery (B) according to one of the preceding claims 3 to 5, wherein a free space (43) is provided between a bottom side (44) of the battery module (1) and the base plate (32) of the base element (9) receiving the battery module (1). [7] Motor vehicle with a battery (B) according to one of claims 1 to 6.

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