Adjustment element for length adjustment of a battery cell pair

Abstract

The invention relates to an adjusting element for adjusting the length of a battery cell pair (25) and a method for manufacturing a battery cell pair (25) with a defined length. The adjusting element (10) according to the invention has at least two opposing clamping bodies (14), each of which has an outwardly oriented contact surface (11) designed to be in contact with a battery cell (20) and an inwardly oriented force-bearing surface (12), wherein a cavity (16) is formed between the force-bearing surfaces (12), which tapers in a direction extending parallel to the contact surfaces (11), and a clamping element (13) is formed which is designed to be inserted into the tapered cavity (16) such that the clamping bodies (14) move away from each other and the contact surfaces (11) are pressed against the respective battery cells (20).

Description

[0001] The invention relates to an adjustment element for adjusting the length of a battery cell pair (cell pair) and a method for producing a cell pair with a defined length. In the context of the application, a battery cell pair is understood to be a pair of two battery cells connected via a cell connector, wherein the cell connector is welded on one side to the cell tap of one battery cell and on the other side to the cell tap of the other battery cell.

[0002] When forming high-performance batteries, several individual battery cells are usually combined to form battery modules, as disclosed, for example, in the documents US 20 2001 36119 A1 and DE 11 2014 006 025 T5. Cell pairs as described above are often used. The formation of a battery module is exemplified in Fig. 1. There, two battery cells 20 are combined to form a battery cell pair 25 and connected to each other via cell taps 21. To connect the two adjacent battery cell pairs 25, a so-called busbar 22 is used, which connects the respective outer cell taps 21 of the battery cell pairs 25.

[0003] The battery cell pairs 25 can be aligned on one side so that they can be connected flush by a busbar 22 (see connection in the drawing plane above). However, due to manufacturing tolerances, particularly when connecting the individual battery cells 21 to battery cell pairs 25, it may happen that the other side of the battery cell pairs 25 cannot be connected flush by a busbar 22, as shown schematically in the Fig. 1 shown.

[0004] To solve this problem, flexible busbars 22 are available in the state of the art, which are capable of compensating for the corresponding offset. However, these are very expensive.

[0005] The prior art further discloses, through document DE 10 2015 201 820 A1, a traction battery spacer with a holding element, which is designed to be arranged between two adjacent battery cells to define a distance between them. Document DE 10 2021 203 549 A1 discloses a holding device by means of which battery cells are positioned relative to one another. Document DE 10 2021 124 831 A1 describes a battery in which pillow-shaped deformation elements are arranged between two adjacent battery cells.

[0006] In view of the prior art described above, it is therefore an object of the present invention to provide a device in the form of an adjusting element for adjusting the length of a battery cell pair and a method for producing a battery cell pair with a defined length, which represent a simple and cost-effective possibility for adjusting the length of a battery cell pair in order to be able to form corresponding battery modules from battery cell pairs of the same length.

[0007] This object is achieved by the subject matter of the independent claims. Advantageous embodiments are contained in the subclaims. It should be noted at this point that the disclosure of advantageous embodiments of the device according to the invention is also to be understood as a disclosure of advantageous embodiments of the method according to the invention, even if the embodiment is disclosed by a feature formulated as a device feature. The same applies in the reverse case.

[0008] The adjustment element according to the invention for adjusting the length of a battery cell pair consisting of two battery cells arranged one behind the other and connected, has at least two oppositely arranged clamping bodies, each of which has an outwardly oriented contact surface designed to be in contact with a battery cell, and an inwardly oriented force-absorbing surface, wherein a cavity is formed between the force-absorbing surfaces, which tapers in a direction extending parallel to the contact surfaces, and a clamping element which is designed to be introduced into the tapered cavity in such a way that the clamping bodies move away from one another and the contact surfaces are each pressed against the corresponding battery cells.

[0009] The adjustment element according to the invention allows the length of the cell pair to be adjusted accordingly, thus compensating for manufacturing inaccuracies. The adjustment element is inserted between the cell pair, and the two battery cells are pressed apart by the clamping element. The further the clamping element is pressed into the tapered cavity, the further the clamping bodies are pressed open, thus separating the battery cells from each other. The term "outwardly oriented" means that the contact surfaces of the two adjacent clamping bodies are oriented in the opposite direction, so that they do not point toward the other clamping body.The opposite is to be understood by the phrase “oriented inwards”, so that the contact surfaces of the bracing bodies oriented in this way are oriented towards the corresponding other bracing body and the hollow body in between.

[0010] In a preferred embodiment of the invention, the contact surfaces of the bracing bodies have at least sections that are arranged parallel to one another and parallel to the insertion direction of the bracing element. Particularly preferably, the entire contact surfaces are arranged in this manner. This ensures a uniform force transmission to the battery cells, thus minimizing mechanical wear.

[0011] In an advantageous embodiment of the invention, the bracing bodies are connected to one another on one side by a base plate. In such an embodiment, movement of the contact surfaces thus occurs only on the side opposite the base plate. Preferably, two or more pairs of two bracing bodies each are provided on an adjustment element, in particular on a base plate. Thus, an adjustment element can be inserted between two battery cells in such a way that the force distribution can be achieved by several bracing bodies. If these pairs of bracing bodies are connected to one another accordingly on a base plate, the handling of the adjustment element can be improved.

[0012] A further advantageous embodiment of the invention is one in which the cavity between the bracing bodies is conical. The conical shape largely encloses the bracing element to be provided therein, preventing it from slipping sideways out of the cavity. This simplifies handling of the adjustment element. The bracing element preferably also has a cylindrical, particularly preferably conical, shape. Bracing elements shaped in this way allow a uniform force to be exerted on the force-absorbing surfaces and thus on the bracing bodies. This is particularly advantageous with regard to the mechanical stress on the components.

[0013] In an alternative advantageous embodiment of the invention, the cavity is wedge-shaped, and the bracing element preferably has a conical and particularly preferably a wedge-shaped shape. In this way, a uniform force distribution across the force-absorbing surfaces can be ensured. Preferably, the bracing bodies are also wedge-shaped, with the contact surfaces of the opposing bracing bodies being parallel. Due to the parallel surfaces of the wedge-shaped bracing bodies, the force exerted on the battery cells can be transmitted very evenly, thus minimizing both the handling of the adjustment element and the mechanical stress on the components, for example in the form of deformation of the bracing bodies.

[0014] A further preferred embodiment of the adjustment element according to the invention further comprises a positioning aid, which has a pulling element connected to the bracing element and protrudes at the tapered end of the cavity between the two bracing bodies. The pulling element allows the bracing element to be pulled into the cavity, eliminating the need to push it in from the other side. Depending on the orientation of the adjustment element between the battery cells, this simplifies the handling of the adjustment element, as it can be operated from both sides.

[0015] Also advantageous is an embodiment of the invention that has a fixing mechanism designed to fix the position of the bracing element in the cavity. This can be achieved, for example, by means of a corresponding positive fit or similar between the bracing element and the force-absorbing surfaces of the bracing bodies. In this way, the bracing element can be fixed during insertion into the cavity, so that, for example, no movement of the bracing element counter to the direction of insertion into the cavity is possible.

[0016] Such an embodiment of the invention is particularly advantageous when the fixing mechanism is formed by tooth-shaped notches on the tension element and a counter-fixing element arranged on the tensioning bodies, into which the notches engage. This represents a possible embodiment of fixing against the direction of movement of the tensioning element by means of a positive locking mechanism. It is also conceivable to provide such a positive locking embodiment with notches directly between the tensioning element and the force-absorbing surface.

[0017] The method according to the invention for producing a battery cell pair with a defined length comprises the following steps. First, two battery cells are provided and arranged such that a cell tap of one battery cell rests against a cell tap of the other battery cell. Subsequently, a cell connector is arranged between the two adjacent cell taps, wherein the cell taps are welded to the cell connector. The cell connector is to be understood as a type of spring element which is designed such that it applies an opposing force to each of the two battery cells, which force is directed such that the battery cells are pressed towards one another. In the next step, an adjusting element, in particular an adjusting element according to the present invention, is arranged between the battery cells laterally next to the cell connector.The adjustment element is designed to apply a force to the battery cells that opposes the force of the cell connector, thus pushing them apart. If this is done using the adjustment element according to the invention, a clamping element is inserted into a tapered cavity of the adjustment element in such a way that two clamping bodies of the adjustment element clamp between the battery cells, and the distance between the battery cells is adjusted depending on the insertion depth of the clamping element into the tapered cavity. Once the desired total length of the battery cell pair has been achieved, the two battery cells are welded together.

[0018] By means of the method according to the invention and in particular by using the adjustment element according to the invention in the method, the length can be precisely adjusted to a predetermined total length. In this way, it can be ensured that all battery cell pairs have the same total length and thus can be connected to a conventional busbar (see Fig. 1) can be connected.

[0019] In an advantageous embodiment of the invention, the method further comprises a method step in which the adjusting element is at least partially removed after the two battery cells have been welded together.

[0020] Advantageous aspects and embodiments of the invention are explained in more detail below with reference to the accompanying figures. They show: Fig. 1 shows a schematic representation of two connected battery cell pairs 25 according to the prior art Fig. 2 shows a schematic representation of a battery cell pair 25 using the adjusting element 10 according to the invention Fig. 3a shows a perspective view of a first embodiment of the adjusting element 10 according to the invention Fig. 3b shows a further representation of the Fig. 3a shown embodiment of the adjusting element 10 according to the invention from below Fig. 3c shows a cross section of the Fig. 3a shown embodiment of the adjusting element 10 according to the invention Fig. 4a shows a perspective view of a second embodiment of the adjusting element 10 according to the invention in the installed state Fig. 4b shows an isolated representation of the Fig. 4a shown embodiment of the adjusting element 10 according to the invention from below Fig. 4c shows a detailed cross-sectional view of the Fig. 4a shown embodiment of the adjusting element 10 according to the invention

[0021] On the Fig. Figure 1 has already been discussed in detail with regard to the prior art. Therefore, further description of the figure will be omitted here.

[0022] Fig. Figure 2 shows a schematic representation of a battery cell pair 25 using the adjusting element 10 according to the invention. It is shown how in Fig. 1 shows the battery cell pair 25, consisting of two battery cells 20, which are connected to one another at their end faces via the corresponding cell taps 21 and a cell connector 23 arranged between them. The cell connector 23 is welded on one side to the cell tap 21 of one battery cell 20 and on the other side to the cell tap 21 of the other, second battery cell 20. Nevertheless, the cell connector 23 allows movement of the battery cell pair 25 in its longitudinal direction. It can be understood as a type of spring element, which applies an opposing force to each of the two battery cells 20, so that they are pressed against one another. Thus, a force is required that counteracts and exceeds the force emanating from the cell connector 23 in order to increase the overall length of the battery cell pair 25.

[0023] For this purpose, an adjusting element 10 according to the invention is arranged at the top and bottom of the cell connector 23 in the plane of the drawing, with the aid of which the total length of the battery cell pair 25 is adjusted, in particular extended, as will be explained in more detail with reference to the other figures.

[0024] Fig. Figure 3a shows a first embodiment of the adjusting element 10 according to the invention in a perspective view from above. The embodiment is also shown in the Fig. 3b and Fig. 3c, so that it is explained with reference to all three figures. Fig. 3b shows the embodiment from below, while Fig. 3c shows a cross section of the adjusting element 10.

[0025] The adjustment element 10 has four bracing bodies 14, which are each grouped in two pairs at two ends of the adjustment element 10. Between each bracing body 14 there is a hollow space 16 which is conical and oriented such that it tapers in one direction. Slots 162 are formed on the sides of the conical cavity 16 so that the two bracing bodies 14 of a pair are not connected to one another in the region of the cavity 16. The cavity 16 is thus formed by the bracing bodies 14, with the shape of the cavity 16 being defined by opposing force-absorbing surfaces 22 of the bracing bodies 14. These are therefore oriented inwards, i.e. towards one another, when viewed from the opposing bracing bodies 14. The other side of the bracing bodies 14 is defined by an outwards-oriented contact surface 11.The contact surfaces 11 of two opposing bracing bodies 14 thus face away from each other. Furthermore, a base plate 17 is provided, which connects the bracing body pairs to each other. The adjustment element of the . Fig. 3a, Fig. 3b and Fig. 3c in such a way in the Fig. 2 arranged so that it extends into the drawing plane of the Fig. 2 and thus one pair of bracing bodies is located further forward and one further back in the plane of the drawing.

[0026] The conical cavity 16 has an opening 161 formed at the thicker end of the tapered cone. To generate the clamping effect of the adjusting element 10, a clamping element 13 (see Fig. 3c) in the direction of the taper of the cavity 16, i.e. in the plane of the Fig. 3c from top to bottom. The bracing element 13 is pressed against the force-absorbing surfaces 12 of the bracing bodies 14, so that they are spread outwards, as in Fig. 3b by the dashed arrows. The adjustment element 10 can be clamped between the battery cells 20 via the external contact surfaces 11. If the clamping element 13 is inserted further into the cavity 16, the force is increased accordingly until it is greater than the force exerted by the cell connector 23 on the battery cells 20, which force presses the battery cells 20 together and thus pushes the battery cells 20 apart. The force can be increased by continually advancing the clamping element 13 further into the cavity until the desired, specified total length of the battery cell pair 25 is reached. The battery cells 20 are then welded together to fix the total length. The adjustment element 10 can then either be removed again or remain between the battery cells 20.

[0027] As in Fig. 2 it is advantageous both above and below (in the plane of the drawing of the Fig. 2) provide appropriate adjustment elements 10 to enable a uniform adjustment of the length. This also requires the use of an adjustment element 10 with the dimensions shown in Fig. 3a and Fig. 3b shown two pairs of bracing bodies make sense.

[0028] The Fig. 4a, Fig. 4b and Fig. 4c show a further embodiment of the adjusting element 10 according to the invention. Fig. 4a shows the adjustment element 10 in an installed state between the battery cells 20. Also visible are the cell tap 21 of a battery cell 20 and the cell connector 23, which is arranged between the battery cells 20 analogously to Fig. 2 is arranged. Fig. 4b shows the embodiment of the adjusting element 10 accordingly in an isolated representation, while Fig. 4c shows a cross-section of a detail of the embodiment.

[0029] In the embodiment according to the Fig. 4a, Fig. 4b and Fig. 4c, the bracing bodies 14 are each designed as opposing wedges. The intermediate cavity 16 thus tapers upwards in the plane of the drawing and is also wedge-shaped. The bracing bodies 14 and the cavity 16 extend across the entire width of the battery cell pair 25. The contact surfaces 11 and the force-absorbing surfaces 12 are provided as flat, planar surfaces.

[0030] In order to exert the appropriate force on the battery cells 20 in this embodiment so that they are pushed further apart, a bracing element 13 in the form of a wedge is inserted from bottom to top into the likewise wedge-shaped cavity 16 between the bracing bodies 14 in the plane of the drawing. As a result, the bracing bodies 14 are pressed outwards, analogous to the embodiment described above, so that a force is applied to the battery cells 20 by the contact surfaces 11, which force pushes the two cells away from each other, i.e. apart. The flat surfaces of both the contact surfaces 11 and the force-absorbing surfaces 12 enable uniform force transmission. It should be noted that embodiments of the invention are also conceivable in which the bracing body 13 is inserted from above into the correspondingly reversed wedge-shaped bracing bodies, as in the first embodiment.

[0031] In order to enable the driving of the bracing element 13 into the cavity 16 in the embodiment shown, a positioning aid 15 is provided, which is arranged in relation to the Fig. 4b and Fig. 4c is explained in more detail.

[0032] The positioning aid 15 has a tension element 151, which is connected to the flat end of the wedge-shaped bracing element 13. By applying a tensioning element 152 in the plane of the drawing Fig. 4b , the tensioning element 13 can be moved from bottom to top. The tensioning element 151 has notches 154 on one side. Furthermore, a counter-fixing element 152 is provided, by which the tensioning element 151 is pulled. The counter-fixing element 152 is supported against the two tensioning bodies 14 by means of a support structure 153. The support structure 153 enables the movement of the tensioning bodies 14 outwards, i.e. in the longitudinal direction of the battery cell pair 25. When the tensile force is applied to the tensioning element 151, the tensioning body 14 can be simply supported in order to prevent the entire adjustment element 10 from being pulled out of the gap between the two battery cells 20. This represents an advantage of the arrangement shown over an inverted arrangement in which the wedge-shaped bracing element 13 would be pressed into the cavity 16 from above.In this case, a complex fastening would have to be provided which prevents the wedge-shaped bracing bodies 14 with the bracing element 13 from being pushed deeper into the gap.

[0033] The catches 154 of the pulling element 151 form a positive connection with corresponding counter-elements of the fixing counter-element 152, which are positively connected in the direction opposite to the movement of the pulling element 151, i.e. in the plane of the drawing of the Fig. 4b and Fig. 4c downwards. Thus, the clamping element 13 can be held in position by the positive locking, similar to what one would expect from a cable tie, for example.

[0034] It should be noted at this point that embodiments with a positioning aid 15 that is shown in a different design are also conceivable.

[0035] After the defined length of the battery cell pair 25 has been set and the battery cells have been welded together, the positioning aid 15 is preferably removed. QUOTES CONTAINED IN THE DESCRIPTION

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

[0000] US 20 2001 36119 A1

[0002] DE 11 2014 006 025 T5

[0002] DE 10 2015 201 820 A1

[0005] DE 10 2021 203 549 A1

[0005] DE 10 2021 124 831 A1

[0005]

Claims

[1] Adjustment element (10) for adjusting the length of a battery cell pair (25) consisting of two battery cells (20) arranged one behind the other and connected, comprising at least two oppositely arranged bracing bodies (14), each having an outwardly oriented contact surface (11) designed to be in contact with a battery cell (20), and an inwardly oriented force-absorbing surface (12), wherein a cavity (16) is formed between the force-absorbing surfaces (12), which tapers in a direction extending parallel to the contact surfaces (11), and a bracing element (13) which is designed to be introduced into the tapered cavity (16) in such a way that the bracing bodies (14) move away from one another and the contact surfaces (11) are each pressed against the corresponding battery cells (20). [2] Adjustment element (10) according to one of the preceding claims, wherein the bracing bodies (14) are connected to one another on one side by a base plate (17). [3] Adjusting element (10) according to one of the preceding claims, wherein the adjusting element (10) has two pairs of two bracing bodies (14) each. [4] Adjustment element (10) according to the preceding claim, wherein the cavity (16) is conical, and the clamping element (13) preferably has a cylindrical, particularly preferably a conical shape. [5] Adjustment element (10) according to one of the preceding claims 1 to 3, wherein the cavity (16) is wedge-shaped and the clamping element (13) preferably has a conical, particularly preferably a wedge-shaped shape. [6] Adjustment element (10) according to one of the preceding claims, wherein the adjustment element (10) further comprises a positioning aid (15) which comprises a tension element (151) which is connected to the bracing element (13) and which protrudes at the tapered end of the cavity (16) between the two bracing bodies (14). [7] Adjusting element (10) according to one of the preceding claims, wherein the adjusting element (10) has a fixing mechanism designed to fix a position of the bracing element (13) in the cavity (16). [8] Adjustment element (10) according to the preceding claim in conjunction with claim 6, wherein the fixing mechanism is formed by tooth-shaped catches (154) on the tension element (151) and a fixing counter-element (152) arranged on the bracing bodies (14), into which the catches (154) engage. [9] Method for producing a battery cell pair (25) with a defined length, comprising the following steps, Providing and arranging two battery cells (20) such that a cell tap (21) of one battery cell (20) rests against a cell tap (21) of the other battery cell (20), Arranging a cell connector (23) between the two adjacent cell taps (21) and connecting the cell taps (21) to the cell connector (23), Arranging an adjusting element (10) between the battery cells (20) laterally next to the cell connector (23), wherein the adjusting element is designed to apply a force between the battery cells which is directed such that the battery cells are pressed apart and thus acts against a force exerted on the battery cells by the cell connector (23), Increasing a distance between the battery cells (20) by means of the adjusting element (10) until a desired total length of the battery cell pair (25) is reached, Welding the two battery cells (20) together. [10] Method according to the preceding claim, wherein the adjusting element (10) is further at least partially removed after the welding of the two battery cells (20).

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