Battery for a motor vehicle and method for bracing prismatic battery cells of a battery

Abstract

The invention relates to a battery (12) for a motor vehicle, wherein the battery (12) has several cell groups (28) arranged side by side in a first direction (x), wherein each cell group (28) comprises several prismatic battery cells (10) arranged in a second direction (y) with their first cell sides (14) having the largest surface area facing each other.It is provided that the battery cells (10) each have a cell pole (18) on two opposing second cell sides (16), wherein the respective battery cells (10) arranged in a straight line next to each other in the first direction (x) are part of an identical cell bar (20) of several cell bars encompassed by the battery (12), wherein the battery cells (10) of a respective identical cell bar (20) are connected in series to each other via their cell poles (18), wherein the battery (12) comprises at least one tension band (36) that spans all battery cells (10) of a cell group unit (38a, 38b, 38c; 38) of the battery (12), and wherein the cell group unit (38a, 38b, 38c; 38) comprises at least one of the cell groups (28).

Description

[0001] The invention relates to a battery for a motor vehicle, comprising several cell groups arranged side by side in a first direction, each cell group comprising several prismatic battery cells arranged in a second direction with their largest first sides facing each other. The invention further relates to a method for clamping prismatic battery cells of a battery.

[0002] Battery cells, especially those in automotive batteries such as high-voltage batteries, can be arranged in a wide variety of configurations. Prismatic battery cells, in particular, are often stacked into a cell stack, which is then placed in a module housing or clamped in the stacking direction. For this, the cells are typically first inserted into the module housing and packed together in a complex process. The modules are then inserted into a battery casing and electrically connected. These processes are typically quite complex and require a significant amount of space within the battery, which could be used more efficiently for a larger number of battery cells.

[0003] DE 10 2021 133 441 B3 describes a battery arrangement with a block-like battery module containing several battery cells in a module housing, with a base plate having a top and a bottom, wherein the battery module is arranged on the top. The battery arrangement is provided to have a tension band that extends across the battery module and is connected to the base plate, so that the battery module can be fixed or secured to the base plate by means of the tension band.

[0004] DE 10 2016 109 512 A1 describes a holding arrangement comprising several battery cells, a heat exchanger structure and a band that pulls the heat exchanger structure and the several battery cells together.

[0005] The object of the present invention is to provide a battery and a method that enable the most efficient possible tensioning of battery cells and the most space-saving arrangement of these.

[0006] This problem is solved by a battery and a method with the features according to the respective independent patent claims. Advantageous embodiments of the invention are the subject of the dependent patent claims, the description, and the figures.

[0007] A battery according to the invention for a motor vehicle comprises several cell groups arranged side by side in a first direction, each cell group comprising several prismatic battery cells arranged side by side in a second direction with their largest first sides facing each other. Furthermore, each battery cell has a cell terminal on two opposite second cell sides, the respective battery cells arranged side by side in a straight line in the first direction being part of an identical cell bar of several cell groups comprised by the battery, the battery cells of each identical cell bar being connected in series via their cell terminals, and the battery comprising at least one tension band spanning all battery cells of a cell group unit of the battery, the cell group unit comprising at least one of the cell groups.

[0008] The invention is based on several insights: Firstly, it is very advantageous and, above all, space-saving to combine the battery cells in so-called cell blocks. Such a cell block comprises several prismatic battery cells of different cell groups arranged side by side. In particular, such a cell block comprises exactly one battery cell from each of the cell groups, with the battery cells comprised of the same cell block being arranged side by side in a straight line in the first direction. Furthermore, the battery cells of a cell block are not stacked in a cell pack as is usual, but are arranged side by side in such a way that their second cell sides, on which a cell terminal is also located, face each other, and these second cell sides do not represent the largest surfaces of such a prismatic battery cell.This results in a shape for such a cell bar, which can also be called a cell blade, a kind of bar-shaped, relatively narrow and elongated battery cell arrangement. Since the cells in such a bar are arranged with their respective poles facing each other, it is possible to connect the cells in series in a particularly space-saving manner. These flat cell bars can then be stacked accordingly in the second direction, so that the battery cells of two cell bars adjacent to each other in the second direction face each other with their largest surface areas, namely the first sides. The respective cell bars also then have an essentially prismatic shape and are stacked in the second direction so that their largest surface areas face each other. In addition, at least one cell group unit is encircled by a tension band.Each cell group unit comprises at least one of the cell groups. A cell group, in turn, comprises several battery cells arranged side by side in the second direction. Each battery cell within such a cell group is part of a different cell bar. In other words, a cell group does not include any other battery cells belonging to the same cell bar. The advantage of this arrangement and type of clamping is that not all battery cells in this arrangement need to be spanned as a whole by a single or a few clamping bands. Instead, the stack of multiple cell bars can be subdivided into several individual cell group units, each of which is then spanned by at least one clamping band.This reduces the length of each tension band, allowing for a significantly more robust clamping assembly of multiple battery cells and a more uniform force distribution. Nevertheless, the battery cells can be easily contacted, especially in the first direction, via their opposing poles and arranged in a particularly space-saving manner. Thus, while conventional cell arrangements are grouped into modules, and the cells within such a module are clamped and contacted with each other, the invention involves grouping the cells into cell groups or cell group units on the one hand and cell bars on the other. Within a cell group unit, the battery cells are encircled by the at least one tension band, while the electrical cell contacting is essentially realized along the cell bars.Additional module housings are unnecessary, and this arrangement can be easily integrated into a complete battery housing. Thus, due to the interlocking of the battery cells and the described tensioning of one or more cell group units, a particularly efficient tensioning of the battery cells and a space-saving arrangement are simultaneously achieved. This arrangement also enables a particularly advantageous battery manufacturing process, as will be described in more detail later in connection with the inventive method and its embodiments.

[0009] The first and second directions defined above are, in particular, perpendicular to each other. Likewise, the third direction, defined later, can be perpendicular to both the first and second directions.

[0010] The battery cells can be, for example, lithium-ion cells. Furthermore, the battery cells are designed as prismatic cells. This means they have an essentially cuboid geometry. Each battery cell thus comprises six cell faces, which are arranged in pairs opposite each other. The first cell faces represent the largest surface area and are opposite each other in the second direction. Each of the first cell faces also has a cell terminal. The cell terminals of a battery cell are therefore also opposite each other in the first direction. Additionally, each battery cell can comprise two third cell faces, which are then opposite each other in the third direction. Preferably, the second cell faces represent the smallest surface area of ​​each battery cell.

[0011] Optionally, additional components, such as cell separators, cooling plates, or similar items, can be arranged between the cell blocks in the second direction. The battery cells arranged adjacent to each other in the second direction therefore do not necessarily have to be in direct contact with each other.

[0012] The battery can be designed, for example, as a high-voltage or medium-voltage battery. In particular, it can be a traction battery for a motor vehicle, especially an electric vehicle. It can also be designed as a stationary energy storage device. The battery can also include a battery housing in which all the battery cells are arranged. Additional module housings are not required and preferably are not.

[0013] It is particularly advantageous if the battery comprises several cell group units arranged side-by-side in the first direction, each spanned by at least one battery tension band. Each of these cell group units thus comprises at least one cell group, for example, a single cell group or several cell groups. The respective cell group units can contain a different number of cell groups. The battery can therefore be subdivided into several cell group units in the first direction, and each of these cell group units can be spanned by at least one battery tension band. Furthermore, a single cell group should comprise all battery cells arranged in a row, i.e., in a straight line to each other, in the second direction.The respective cell groups preferably comprise the same number of battery cells, and the cell bars preferably also comprise the same number of battery cells. This simplifies the assembly and wiring. Nevertheless, an unequal number of battery cells in the respective cell groups and / or cell bars is also possible.

[0014] The at least one tension band, as well as any optional additional tension bands, can be made of a metallic material, for example steel or stainless steel, or they can be made of or comprise a plastic, in particular a fiber-reinforced plastic and / or a woven tape-reinforced plastic. Suitable fibers for such fiber-reinforced plastic or woven tape-reinforced plastic include, in particular, glass fibers and / or carbon fibers and / or aramid fibers or similar materials.

[0015] According to a further advantageous embodiment of the invention, one direction of rotation of the tension band, in which it spans the battery cells, is perpendicular to a third direction, in particular the aforementioned third direction. Additionally or alternatively, the battery can also comprise two tension bands spanning the same cell group unit, whose directions of rotation are parallel to each other and which are spaced apart in the third direction. This arrangement of the tension bands is particularly advantageous because, for example, one of the two tension bands can be arranged above the respective cell terminals of a battery cell with respect to the third direction, and the other below the cell terminals. The distance that the two tension bands spanning the same cell group unit have from each other in the third direction can, for example, correspond to at least the height of a cell terminal in the third direction.Furthermore, the design with two tension bands enables a particularly even distribution of force. Depending on how many cell groups are encompassed by the cell group unit, the tension band spanning this cell group unit contacts at least some of the enclosed battery cells, especially outer battery cells and / or pressure plates optionally arranged between the outer battery cells and the tension band(s).In the arrangement where the direction of rotation of the tension band is perpendicular to the third direction, which in turn is perpendicular to the first and second directions defined above, the first and / or second sides of at least some of the battery cells in the cell group unit are directly contacted by the tension band or rest against it, and / or the pressure plates provided on the first sides of the battery cells located on the outside with respect to the second direction are contacted by the tension band(s). With respect to a standard installation position in a motor vehicle, where the third direction corresponds to a vehicle's vertical direction, the direction of rotation is, so to speak, horizontal.If the battery cells are to be arranged on a cooling surface or cooling plate located, for example, below and / or above the battery cells in the third direction, this arrangement of the at least one tensioning band also reduces the distance to the cooling surface or cooling plate. In other words, each cell group unit can be tensioned by means of the at least one tensioning band in such a way that the band is not located between the battery cells and such a cooling surface or cooling plate located above and / or below the cells. Such a cooling surface or cooling plate can also be considered part of the battery. Furthermore, with such horizontal clamping, the number of required tensioning bands can be significantly reduced, as will be explained in more detail later.

[0016] According to a further advantageous embodiment of the invention, the cell group unit comprises exactly two cell groups arranged adjacent to each other in the first direction, or exactly three cell groups arranged adjacent to each other in the first direction. It is particularly advantageous if the cell group unit comprises exactly two cell groups arranged adjacent to each other in the first direction. However, spanning three cell groups by means of the at least one tension band is also possible. The main advantage here is that, firstly, more than just a single cell group is spanned by one tension band. Thus, several cell groups can be spanned simultaneously by the same tension band, which reduces the overall number of tension bands required.It is also advantageous if not too many cell groups are spanned by a single tension band, as this increases the robustness of the tensioning and results in a more uniform force application. Therefore, it is highly beneficial if such a cell group unit comprises either only two or only three cell groups, although more than three cell groups would also be possible.

[0017] Clamping more than one cell group also has the advantage that there is a gap between the cell groups spanned by the same tension band, in which no tension band, or no part of the tension band spanning the cell group unit, runs. This allows for particularly easy connection of taps, for example, voltage taps or current taps for voltage and / or current sensors, as will be explained in more detail later, since there is still sufficient space in these gaps, even after the cell group unit has been clamped, to make such connections.

[0018] According to a further advantageous embodiment of the invention, two opposing cell poles of battery cells of the same cell block are electrically connected via a curved and / or flexible cell connector. Providing such a cell connector, which can also be called a pole connector, advantageously allows for tolerance compensation between the cell poles of adjacent battery cells that are to be electrically connected. Such a cell connector can, for example, be U-shaped. The flat legs of such a U-shape of the cell connector can each be electrically connected to a cell pole, for example, by being welded to it. Due to the U-shape and / or also by making such a cell connector sufficiently thin, it can be easily designed to be flexible. In other words, such a cell connector allows a certain degree of movement, especially in the first direction.It is also conceivable that, due to its flexible design and construction, such a cell connector could only be brought into its final, curved shape after it has been contacted with the cell terminals of the two battery cells to be electrically connected. In other words, such a cell connector could, for example, first be welded to two cell terminals of two cells and then bent into its curved shape. This allows for particularly easy interconnection of the battery cells in a cell block.

[0019] According to a further advantageous embodiment of the invention, the battery comprises at least one electrical tap which is connected to a cell terminal or cell connector in a space between two cell groups and which extends from the space via an electrical conductor, particularly in which no tension band runs through the space. The tap can, for example, be used for voltage monitoring to detect a cell voltage. Several cell terminals and / or terminal connectors, i.e., cell connectors, can also be provided with such taps. This advantageously enables voltage monitoring of the battery cells or monitoring of other battery cell parameters, such as cell current and / or cell temperature, or similar parameters. The taps can, for example, be connected to an FPC (flexible printed circuit board).Such a flexible printed circuit board (FPC) can, for example, be routed outside the space between the cells on the outer side of the battery cell assembly. The corresponding taps can then be easily routed out of the space via the electrically conductive connection and connected to such an FPC. This also includes the FPC itself comprising connecting tabs that incorporate the electrically conductive connections, which extend into the space from outside and are each contacted at least one of the cell terminals and / or terminal connectors. The connection of the taps to the cell terminals or terminal connectors can also be achieved, for example, by welding. Providing such taps in spaces where no tension band is present has the advantage of providing more installation space for contacting or welding these taps. This facilitates the contacting process.Not every cell pole or pole connector needs to be equipped with such a tap. Therefore, for example, it is possible to omit taps in the area of ​​spaces where one or more tension bands are guided.

[0020] For example, the battery can comprise first and second spaces, each of which is arranged between two cell groups adjacent to each other in the first direction, wherein a part of the at least one tension band runs in the first spaces and no part of the at least one tension band or any part of another tension band runs in the second spaces, wherein the taps are then preferably arranged exclusively in the second spaces, i.e., that no taps should be provided in the first spaces.

[0021] According to a further advantageous embodiment of the invention, one direction of rotation of the tension band, in which it spans the battery cells, is perpendicular to the first direction, particularly in that the cell group unit comprises only a single cell group. With respect to the intended installation position in a motor vehicle defined above, the at least one tension band is thus vertically oriented with respect to its direction of rotation according to this embodiment, i.e., it lies in a vertical plane and not in a horizontal plane. In this case, it is advantageous if at least one such tension band is provided for each cell group, but preferably two tension bands per cell group to enable the most uniform force distribution possible. In contrast to the previously described variant with the at least one horizontally running tension band, more tension bands are required per cell group in this case.In other words, multiple cell groups (within a common cell group plane) cannot be spanned by a single tension band. However, this variant has the advantage that more installation space is available in all the gaps between cell groups that are adjacent to each other in the first direction. This space is particularly advantageous for connecting taps, such as the voltage taps described above. In other words, with this variant, no part of a tension band runs through any of these gaps. Furthermore, according to this embodiment, the tension band can also be used as a spacer for a cooling plate or cooling surface that is arranged above or below the battery cells with respect to the third direction.

[0022] Furthermore, as already mentioned, this variant offers the advantage of having two tension bands encircling the same cell group unit, with their directions of rotation parallel to each other and a distance between them in the first direction. In particular, each cell group can be encircled by two tension bands that run parallel to each other and are spaced apart in the first direction. This ensures a particularly uniform encirclement of each cell group.

[0023] Even with this type of transformer, i.e., vertical transformer, the battery cells can be connected to each other via cell connectors, as described above. The provision of taps and their routing from the spaces between the cells via electrical conductors can also be carried out in the same manner as described above.

[0024] Furthermore, the invention also relates to a motor vehicle with a battery according to the invention or one of its embodiments. The battery can, for example, be designed as a high-voltage battery. In particular, the battery can be a traction battery of the motor vehicle. The motor vehicle can, for example, be an electric vehicle.

[0025] The battery can, for example, comprise numerous cell modules, in particular more than ten, for example, more than 20. Furthermore, the battery can comprise more cell modules than cell groups. In addition, the battery can comprise at least two or three or more cell groups, for example, more than four or five, preferably a maximum of ten.

[0026] The motor vehicle according to the invention is preferably designed as a motor vehicle, in particular as a passenger car or truck, or as a passenger bus or motorcycle.

[0027] Furthermore, the invention relates to a method for clamping prismatic battery cells of a battery which has several cell groups which are arranged next to each other in a first direction, wherein each cell group comprises several of the prismatic battery cells which are arranged in a second direction with their largest surface areas facing each other.The battery cells each have a cell pole on two opposing second cell sides, with several cell bars being provided for arranging the battery cells, each comprising the respective battery cells arranged straight next to each other in the first direction and connected in series to each other via their cell poles, the cell bars being arranged next to each other in the second direction so that the battery cells of the same cell group face each other in the second direction with their largest surface areas, and with at least one tension band spanning all battery cells of a cell group unit of the battery comprising at least one of the cell groups.

[0028] The advantages described for the battery according to the invention and its embodiments apply equally to the method according to the invention.

[0029] According to a further advantageous embodiment of the invention, after arranging the cell bars side by side in the second direction and before clamping them with the tension band, the multiple cell bars are pressed together in the second direction by means of a pressing device, and the cell group unit is clamped with the at least one tension band, while the cell bars are held in the compressed state by the pressing device. Thus, it is possible to pre-tension the cell bars in the second direction using the pressing device before the tension bands are clamped around the respective cell group units. This allows for particularly simple attachment of the tension bands.

[0030] According to a further advantageous embodiment of the invention, at least two pressure plates extending longitudinally in the first direction are provided, between which the cell bars are arranged during pressing, wherein the cell bars are pressed together via the pressure plates by means of the pressing device with respect to the second direction, in particular wherein pressure is exerted on several cell groups simultaneously by means of one of the respective pressure plates.

[0031] The arrangement of multiple cell blocks can be limited, for example, in and against the second direction by one of these second pressure plates. The pressure plates can also be part of the battery. Thus, the pressure plates can extend across all cell groups in the second direction. For example, a pressure plate in the second direction can be as long as a cell block. This allows all cell groups of the battery to be compressed simultaneously and therefore particularly uniformly with respect to the second direction using only two pressure plates.

[0032] If the pressure plates are to remain in the battery, they can also be at least partially spanned by the at least one tension band. With horizontal tensioning, it is advantageous if the pressure plates then have, for example, in the area adjacent to a first gap in which at least part of the at least one tension band, or even parts of several tension bands, run, a recess and / or a slot that extends, for example, from an edge that delimits the respective pressure plate in and / or opposite to the first direction towards the center of the pressure plate as defined with respect to the third direction. With a vertical arrangement of the at least one tension band, no recesses or slots are provided in the pressure plates.

[0033] The pressing device can engage the pressure plates when compressing the cell bars. Alternatively, the pressing device can include separate pressure plates. These plates can then, for example, be positioned against the first and last cells of a cell group (in the second direction) or against a pressure plate adjacent to them, such that they do not completely cover the corresponding first cell sides or the pressure plates in the third direction, but rather only contact them in a central area. This allows for the simple placement of the corresponding tensioning bands above and below these pressure plates, in the third direction, to clamp the respective cell group units without clamping the pressure plates themselves. These bands can then be removed after clamping.If, on the other hand, a vertical clamping action, as described above, is to be implemented, the pressure plates can also be designed differently, for example, comb-like, and engage the respective first cell sides of the outer battery cells or the pressure plates in such a way that they do not completely cover them with respect to the second direction, for example, only in a central area of ​​the respective cell group with respect to the first direction. This also allows for easy application of the corresponding clamping bands.

[0034] According to a further advantageous embodiment of the invention, the battery cells of an identical cell block are electrically contacted via cell connectors before the cell blocks are provided. This can be done, in particular, as described above. The cell connectors can be flexible and / or curved, as described above, which allows for easy interconnection of the battery cells and their arrangement into a cell block.

[0035] According to a further advantageous embodiment of the invention, after clamping with the at least one clamping band, and in particular after removing the pressing device, at least one electrical tap is connected to a cell pole or cell connector in a space between two cell groups, for example by welding, wherein the tap is led out of the space via an electrical conductor. The connection of such taps can therefore take place after the cells have been clamped and, in particular, after the pressing device has been removed. During the connection of these taps, the cells are thus already in a clamped state. This facilitates the connection of the taps, since a subsequent change in the position of the battery cells is no longer to be expected.

[0036] The invention also includes further developments of the method according to the invention, which have features already described in connection with the further developments of the battery according to the invention. For this reason, the corresponding further developments of the method according to the invention are not described again here.

[0037] The invention also includes combinations of the features of the described embodiments. The invention therefore also includes realizations that each exhibit a combination of the features of several of the described embodiments, provided that the embodiments have not been described as mutually exclusive.

[0038] The following are exemplary embodiments of the invention described. This is illustrated by: Fig. 1 a schematic representation of the electrical contacting of two battery cells for a battery according to an embodiment of the invention; Fig. 2 a schematic representation of a cell bar with electrically contacted battery cells for a battery according to an embodiment of the invention; Fig. 3 a schematic representation of a cell bar after the electrical contacting of the battery cells for a battery according to an embodiment of the invention; Fig. 4 a schematic representation of several cell bars arranged side by side during pre-tensioning according to an embodiment of the invention; Fig. 5 a schematic representation of the pre-tensioned cell bars of a battery after the application of the tensioning bands according to an embodiment of the invention; and Fig. 6 a schematic representation of a battery with vertically spanned cell groups according to a further embodiment of the invention.

[0039] The exemplary embodiments described below are preferred embodiments of the invention. In these exemplary embodiments, the described components each represent individual features of the invention, which can be considered independently of one another and each further develops the invention independently. Therefore, the disclosure is intended to include combinations of features of the embodiments other than those shown. Furthermore, the described embodiments can also be supplemented by further features of the invention already described.

[0040] In the figures, identical reference symbols denote functionally equivalent elements.

[0041] Fig. Figure 1 shows a schematic representation of two battery cells 10 for a battery 12 (see Figure 1). Fig. 4 and Fig. 5) during electrical contacting according to an embodiment of the invention. The battery cells 10 are designed as prismatic battery cells 10. These comprise two first sides 14, which represent the sides of the battery cells 10 with the largest surface area. They also comprise two second sides 16, which are also opposite each other and on which a cell pole 18 is arranged. They also each comprise two third sides 19, which are also opposite each other. The battery cells 10 are to be arranged in cell blocks 22 (see, for example, Fig. 3) are arranged such that their respective cell poles 18 face each other and the cells 10 are also electrically connected in series. Pole connectors 24, which can also be referred to as cell connectors 24, are preferably used to connect the cell poles 18. Such a pole connector 24 can be curved and / or flexible. It can be electrically connected to the respective facing cell poles 18 of two cells 10, for example by welding. Welding is referred to here as 26. During welding 26, the cells 10 can be arranged at an angle to each other due to the flexibility of the pole connector 24, which facilitates the welding process 26. They can then be aligned with each other so that their respective second sides 16 are parallel to each other.In the present example, a pole connector 24 is used for this purpose, which, after such alignment, has a U-shaped cross-section perpendicular to the y-direction shown here. Alternatively, a cell connector 24 can also be used, which has such a U-shaped cross-section perpendicular to the z-direction, as shown in the example in . Fig. Figure 2 shows that after electrical contact of the cell poles 18 via the cell connectors 24 and alignment of the cells 10 to each other, a cell bar 20 is finally provided, as shown schematically in Figure 2. Fig. Figure 3 illustrates this. In the present example, such a cell block 20 comprises several battery cells 10 arranged side by side in the x-direction, their second sides 16 facing each other, and electrically contacted via their cell terminals 18 and the cell connectors 24 in a series connection. In this way, the battery 12 to be manufactured (see, for example, Figure 3) can be... Fig. 4 and Fig. 5) Several such cell bars 20 are provided.

[0042] Fig. Figure 4 shows a schematic representation of a battery 12 with several such cell blocks 20 arranged side by side in the y-direction, in particular, by way of example, 12 such cell blocks 20. Each cell block 20 comprises the same number of battery cells 10. The cell blocks 20 are arranged relative to each other such that several cell rows are formed, which are also referred to as cell groups 28, and the number of these cell groups corresponds to the number of cells 10 in a single cell block 20. The cells 10 of a cell group 28 are thus arranged in a straight line relative to each other in the y-direction. The cell groups 28 are, in turn, arranged side by side in the x-direction.

[0043] Before tensioning, the cell bars 20 are first pre-tensioned in the y-direction, as illustrated by arrows 30. A pressing device 32 can be used for this purpose, as well as two pressure plates 34, of which only one is shown here. The cell bars 20 can be arranged between these pressure plates 34 with respect to the y-direction and tensioned in the y-direction via the pressure plates 34. Optionally, one such pressure plate 34 can extend across all cell groups 28 in the x-direction. However, a separate pressure plate 34 or a separate pair of pressure plates 34 can also be provided for each individual cell group 28. Subsequently, while the cell bars 20 are held in the pre-tensioned state by means of the pressing device 32, tension bands 36 can now be attached, as shown schematically in Fig. Figure 5 is shown. The pressure plates 34 can be clamped together and remain permanently in the battery 12. The cell rows, in particular the cell group units 38a, 38b, 38c, can then be bound together in the compressed state with the clamping band 36 (see Figure 5). Fig. 5).

[0044] Fig. Figure 5 shows a schematic representation of battery 12. Fig. 4, which now comprises several tension bands 36. In the present example, the battery 12, or rather its battery cells 10, is divided into several cell group units 38a, 38b, 38c. The first cell group unit 38a comprises two cell groups 28 arranged adjacent to each other in the x-direction, as does the second cell group unit 38b, and the third cell group unit 38c comprises three cell groups 28 arranged adjacent to each other with respect to the x-direction. In the present example, each cell group unit 38a is spanned by two tension bands 36, which have a distance D between them with respect to the x-direction shown here and run essentially parallel to each other. The direction of rotation of the tension bands 36 is oriented perpendicular to the z-direction shown in the present example. The direction of rotation is also designated U1 in the present example.The tension bands 36 lie, so to speak, horizontally with respect to their intended installation position in the motor vehicle, according to which the depicted z-direction corresponds, for example, to a vehicle vertical direction. According to this arrangement, firstly, there are spaces 40a between the cell groups 28 in which no tension bands 36 run, and secondly, spaces 40b in which tension bands 36 or sections thereof run.

[0045] After the tension bands 36 have been applied, taps, in particular voltage taps, can be attached to the cell poles 18 or the cell connectors 24. This attachment can be carried out, for example, by welding and is designated 42 in this document. The voltage tap can be attached, in particular, by laser welding or ultrasonic welding in the narrow space 40a between the cells 10. Such taps are preferably attached only to those poles or pole connectors 24 that are located in spaces 40a where no tension bands 36 run. This space measures, for example, a maximum of 12 mm in the x-direction. Advantageously, there is sufficient space here to provide or attach these taps.Furthermore, the taps can then be more easily routed out of the spaces 40a via appropriate electrical conductors and, for example, to an FPC, and do not need to be routed via tension band sections of the tension bands 36. It can be provided that each cell connector 24 located in such a space 40a is equipped with one or more corresponding taps.

[0046] Furthermore, after tensioning or applying the tension bands 36, the outer cell poles 18a can also be contacted with each other according to a desired circuit arrangement. This can also be done via suitable cell connectors, which are not shown here.

[0047] Fig. Figure 6 shows a schematic representation of a battery 12 according to a further embodiment of the invention. The battery 12 can generally be designed as described above, except for the differences described below: These relate essentially only to the arrangement of the tension bands 36. In this example, these do not span the respective cell groups 28 or cell group units 38 horizontally, but instead vertically. In other words, the direction U2 of the respective tension bands 36 is now oriented perpendicular to the x-direction shown. In this example, each cell group unit 38 simultaneously represents exactly one cell group 28 and is spanned by two tension bands 36, which in turn run essentially parallel to each other and have a distance D2 between them. Here, too, the tension bands 36 are applied while the cell bars 20 are held under preload by means of the pressing device 32.

[0048] This variant of the arrangement of the tension bands 36 has the advantage that there are no tension bands 36 in any of the spaces 40a between the cell groups 28. Therefore, contact points can be easily provided in any of these spaces 40a.

[0049] In particular, each cell connector 24 in such an interval 40a can be easily provided with one or more corresponding taps. However, more tension bands 36 are required for this type of clamping compared, for example, to... Fig. 5. In this example, the tension bands 36 can additionally serve as spacers for a cooling plate or cooling surface, which can be arranged below or above the cells 10 with respect to the z-direction. The example from Fig.In contrast, 5 allows for significantly smaller distances to such a cooling surface or cooling plate, since no tension bands 36 run below or above the cells 10 with respect to the z-direction.

[0050] Overall, the examples demonstrate how the invention can provide a tension band for a so-called cell-to-pack approach. In a cell-to-pack concept, many cells can be assembled and connected to form a pack or stack. Voltage taps can also be attached to the cells, and the signals can be routed via FPC lines to a higher-level control unit, in particular a CMC (Cell Module Control). Due to the elimination of a separate module housing and usually also due to the higher number of cells in a stack, integrating the cells into the assembled battery is more complex than with a conventional module design using separate module housings. To minimize cell contact tolerances and facilitate handling of the pack during the production process, an advantageous clamping system for the cell stacks can be employed.The specific purpose here is to assemble prismatic cells with lateral pole arrangement into a cell blade and to connect these blades in multiple rows to form a larger battery stack. This allows for optimal use of installation space. In particular, the space between two transverse cell rows, i.e., between the aforementioned cell groups in the x-direction or the second direction, can be kept as small as possible. For example, two cell groups, or even more than two cell groups, are clamped together with a tension band, and the free space between the cells, where no tension band runs, can be used for FPC contacting. Overall, this allows the free clamping length of the tension bands to be kept particularly short, resulting in a very robust and uniform clamping.

[0051] In detail, several cells can now be connected to form a cell blade at their lateral cell poles, particularly using cell pole connectors. In this specific case, this can be achieved, for example, by laser beam welding. The resulting cell blades are then aligned, and end plates or pressure plates are attached to the outermost cells. The cell stack can then be pressed together over the end plates, thus pre-tensioning them. In this pre-tensioned state, the previously described application of tension bands, for example, around two to three cell rows, or cell groups, takes place. Subsequently, the connector for the FPC (Fiber Composite Connector) can be welded on to allow for tension tapping in the space where no tension band runs, rather than in the space between the cells enclosed by the respective tension band area. This type of clamping allows for a particularly space-optimized installation.When the tension band is positioned horizontally, it is advantageous to tension it around only two cell rows, i.e., cell groups, and not, for example, the entire seven-row cell pack, because the clamping length would be too great in this case. Wrapping it around each individual cell group, on the other hand, is also less advantageous, as it then becomes more difficult to attach the FPC (Fiber Control Panel) to the cells for tension pickup. Therefore, tensioning around two rows, i.e., around two cell groups, represents the optimum.

[0052] The tension band can also be attached transversely, i.e., vertically, around the cell package, i.e., the cell groups. The advantage here is that the band can be used as a spacer for the thermally conductive compound or adhesive, which can be applied between the cells and a cooling surface or cooling plate positioned above or below. A disadvantage compared to horizontal tensioning, however, is the doubled setup effort required for tensioning, due to the need for two tension bands per cell row, i.e., cell group. Furthermore, when a cell group is clamped vertically, the cooling surface between the cell and the cooling plate is reduced by the application of the bands. This disadvantage does not exist with horizontal tensioning.

[0053] The end plates distribute the force of the tensioning straps across the outer surfaces, preventing a single point of pressure on the cells. The end plates can also be positioned so that they are encircled by the tensioning straps and remain within the battery to ensure consistently uniform pressure distribution. Furthermore, the end plates can be designed with rounded edges to guarantee a sufficiently large tensioning strap radius. QUOTES INCLUDED IN THE DESCRIPTION

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

[0000] DE 10 2021 133 441 B3

[0003] DE 10 2016 109 512 A1

[0004]

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