Module housing for a battery module

Abstract

The present invention relates to a module housing (1) for a battery module (2) of a battery (4), in particular a vehicle battery, comprising a housing wall (6), which can be subjected to an operating pressure (P1) on the inner side of the housing, and a counterpressure device (8) for counteracting the operating pressure (P1), which is configured to provide a counterpressure (P2) on the housing wall (6) on the outer side of the housing, wherein the counterpressure device (8) has a tensioning means (10) for providing a tensioning force (F) and a pressure medium (12) for transmitting the tensioning force (F) onto the housing wall (6), and wherein, in an assembled state, the pressure medium (12) is arranged between the tensioning means (10) and the housing wall (6) in order to transmit the tensioning force (F) in the form of the counterpressure (P2) onto the outer side of the housing wall.

Description

[0001] Module housing for a battery module

[0002] Technical area

[0003] The present invention relates to a module housing for a battery module of a battery and a corresponding battery module.

[0004] State of the art

[0005] It is known to design housings for battery modules to be particularly rigid so that the housing wall can withstand the increased internal pressure that may exist within the battery module. Increased internal pressure can result from exceptional events, such as thermal runaway of a battery cell within the battery module. Increased internal pressure can also prevail in a stress state, such as severe thermal stress on battery cells within the battery module due to intensive charging or discharging. Furthermore, increased internal pressure can prevail in the case of immersion cooling during a normal operating state of a battery module.

[0006] Immersion cooling is a well-known cooling method for traction batteries for electric vehicles, also known as vehicle batteries. An immersion fluid in the form of a dielectric cooling fluid, such as mineral oil, flows around the battery cells arranged in the battery module. This flow creates an increased internal pressure in the battery module.

[0007] DE 102021 107 003 A1 proposes stiffening a module housing against the internal pressure of an immersion cooling system by providing several clamping elements within the module housing that clamp the housing base plate and the housing cover together, so that a defined distance between the base plate and the cover is maintained even under the influence of the increased internal pressure. A disadvantage of this can be seen in the fact that the assembly effort for the internal clamping elements is quite high and, moreover, they take up valuable installation space within the module housing. Other conventional approaches provide for stiffening the housing wall itself, for example, by providing a stiffened sandwich panel as a wall panel for the housing wall. For example, DE 10 2021 128 304 A1 proposes an auxiliary element in the form of a honeycomb plate in a sandwich construction for stiffening a housing wall.Furthermore, it is known to stamp a housing wall, for example by means of deep drawing, in order to increase the inherent rigidity of the housing wall in a geometric manner.

[0008] These known approaches have the disadvantage that stiffening the housing wall requires a considerable amount of installation space. For example, sandwich construction or stamping can require several times the thickness of the actual outer skin of a housing. Furthermore, these solutions result in a comparatively high housing weight.

[0009] Description of the invention

[0010] Based on the known prior art, it is an object of the present invention to provide an improved module housing for a battery module of a battery and an improved battery module.

[0011] The object is achieved by a module housing having the features of claim 1. Advantageous further developments emerge from the subclaims, the description, and the figures.

[0012] Accordingly, a module housing for a battery module of a battery, in particular a vehicle battery, is proposed. The module housing comprises a housing wall, which can be subjected to an operating pressure on the inside of the housing, and a counterpressure device for counteracting the operating pressure. The counterpressure device is designed to provide a counterpressure on the housing wall on the outside of the housing, wherein the counterpressure device has a clamping means for providing a clamping force and a pressure medium for transmitting the clamping force to the housing wall. In an assembled state, the pressure medium is arranged between the clamping means and the housing wall in order to transmit the clamping force in the form of counterpressure to the outside of the housing wall.

[0013] In the context of the present disclosure, the "mounted state" refers to a state in which the counterpressure device is mounted on the module housing, such that the counterpressure device provides the counterpressure on the housing wall on the outside of the housing. Furthermore, "outside of the housing / inside of the housing" refers to directions, forces, or components that are directed, act, or arranged outside / inside the module housing.

[0014] Furthermore, an operating state of the battery module or battery is understood to mean a state in which the battery module or battery is operated in a design-based normal state. For example, a damaged state, particularly in the form of thermal runaway, is not considered a design-based normal state.

[0015] Furthermore, the operating pressure refers to the pressure present within the module housing. For example, the operating pressure can be generated by an immersion fluid flowing around the battery cells during immersion cooling within the module housing. In particular, the operating pressure can be present on the inside of the module housing, i.e., on the housing wall.

[0016] Furthermore, in this case, the housing wall refers to the outer casing of the battery module. For example, in the case of a cuboid module housing, the housing wall comprises the corresponding six housing sides or housing walls.

[0017] Because the pressure medium is arranged between the clamping device and the housing wall in the assembled state to transfer the clamping force to the housing wall in the form of counterpressure, a counterpressure can be provided that acts on the outside of the housing wall and thus counteracts the operating pressure acting on the inside of the housing wall in the operating state. This prevents the operating pressure from deforming the housing wall, in particular causing it to bulge outwards.

[0018] In particular, the clamping device can optionally be released again in the assembled state, making the assembly particularly easy to disassemble. Because the pressure medium is arranged between the clamping device and the housing wall in the assembled state, the clamping device can be released particularly easily, optionally by cutting or severing it.

[0019] Furthermore, the pressure medium can be attached to the outside of the housing wall. For example, the pressure medium can be integrated into the housing wall. In this way, only the clamping device needs to be installed for assembly, while the pressure medium is already pre-positioned.

[0020] Furthermore, the pressure medium can be attached to the outside of the housing wall. For example, the pressure medium can be provided as a structural component that is positioned and aligned on the housing wall during assembly and then secured, for example, by soldering, welding, gluing, or screwing. This provides sufficient freedom for positioning the pressure medium as required.

[0021] Furthermore, the pressure medium can be tubular or rod-shaped. The term "tubular" includes, for example, a square tube, while "rod-shaped" includes cross-sections in the form of an I-beam, L-beam, T-beam, or double-T-beam, as well as cross-sections with a flat bottom and a curved top. For example, a flat bottom can be adapted to a flat housing wall on the outside, and a curved top can be adapted to a curved profile of the clamping device.

[0022] Furthermore, the pressure medium can extend parallel to a housing outer edge. This allows the counterpressure to be applied particularly evenly to the housing wall in the area of ​​the housing outer edge. For example, the pressure medium can extend parallel to two adjacent housing outer edges. This allows the counterpressure to be applied particularly evenly to a housing side located between the two adjacent housing outer edges.

[0023] Furthermore, the clamping device can enclose the housing wall. For example, the clamping device can be guided over four sides of a cuboid module housing to enclose them. This allows the clamping device to completely enclose the perimeter of the housing wall, for example. This allows the clamping device to be installed particularly easily, while the clamping force can be transferred very evenly from the clamping device to the module housing.

[0024] Furthermore, thanks to an enclosing clamping device, separate fastening devices for attaching the clamping device, such as hooks, eyelets or similar fastening devices known for clamping, are no longer required.

[0025] Furthermore, thanks to an enclosing clamping device, the provision of the clamping force can be largely decoupled from the positioning of the pressure medium. For example, a pressure medium comprising two individual rod-shaped pressure elements aligned parallel to each other can be arranged on a single housing side. In this way, the clamping force can be transferred to the two pressure elements, so that by positioning the two pressure elements, the counterpressure can be provided as required on the housing wall, i.e., the relevant housing side.

[0026] Furthermore, the tensioning device can comprise a strapping band or be formed by a strapping band. This allows for a reliable and predictable tensioning device, which greatly simplifies the design.

[0027] According to a further development, the strapping band can have a thickness of 0.3 to 0.7 mm and a width of 8 to 25 mm. This allows for the provision of very lightweight tensioning devices. Furthermore, the strapping band can be a steel band with a tensile strength in the range of 800 to 1200 N / mm 2 This allows for a very robust tensioning device. Furthermore, the strapping band can have a tension in the range of 1000 to 8000 N when assembled. This allows for a high and easily adjustable tension force.

[0028] Furthermore, the housing wall can be formed essentially from a lightweight material; in particular, the housing wall can comprise a fiber-reinforced plastic material, in particular a CFRP material. In this way, a particularly lightweight module housing can be provided.

[0029] The above-mentioned object is further achieved by a battery module having the features of claim 10. Advantageous further developments emerge from the subclaims as well as the present description and the figures.

[0030] Accordingly, a battery module for a battery, in particular a vehicle battery, is proposed. The battery module comprises the module housing and its components according to the above description. Accordingly, the module housing comprises the counterpressure device in the assembled state. Furthermore, the battery module comprises an immersion fluid for immersion cooling. As described above, in the operating state, the immersion fluid applies the operating pressure to the housing wall on the inside of the housing. The counterpressure device is designed to provide the counterpressure on the housing wall on the outside of the housing in order to counteract deformation of the housing wall when subjected to the operating pressure.To avoid repetition, it should be noted that those skilled in the art will recognize from the above description that the technical effects and advantages associated with the proposed battery module include those effects and advantages of the module housing described above. Therefore, repetition is omitted here.

[0031] Furthermore, the clamping means can comprise a plurality of clamping elements. Additionally or alternatively, the pressure means can comprise a plurality of pressure elements. In particular, the clamping means / pressure means or clamping elements / pressure elements can be designed as described above.

[0032] Furthermore, a battery module arrangement according to claim 14 is proposed, comprising at least two battery modules as described above, wherein the clamping means encloses at least two module housings. Thus, a single clamping means can enclose multiple module housings, so that a clamping force can be provided for each of the multiple module housings, which can exert a counterpressure on the respective housing wall by means of the pressure means. For example, the clamping means can comprise a series of three strapping bands that are aligned parallel to one another and enclose the housing walls of two adjacently arranged battery modules.

[0033] Furthermore, according to claim 15, a method for producing a battery module assembly comprising at least two battery modules is proposed. The method comprises the steps:

[0034] - positioning the at least two battery modules so that the at least two battery modules are arranged adjacent to one another;

[0035] - Mounting a counterpressure device on the adjacently positioned battery modules, comprising: attaching a pressure medium to a housing wall of at least one of the battery modules for transmitting a clamping force to the housing wall and attaching a clamping means for providing the clamping force, so that the pressure medium is arranged between the clamping means and the housing wall in an assembled state in order to transmit the clamping force in the form of a counterpressure to the outside of the housing wall.

[0036] To avoid repetition, it should be noted that those skilled in the art will recognize from the above description that the structural elements and arrangements disclosed with the proposed module housing, the battery module, and the battery module assembly, as well as the associated technical effects and advantages, equally apply and are applicable to the proposed methods. For example, the structural components according to the method may correspond to those of the devices proposed above, including the embodiments and exemplary embodiments of the structural components disclosed for the devices according to the following description of the figures.

[0037] Furthermore, according to claim 16, a method for disassembling a battery assembly produced using the method according to claim 15 is proposed. The disassembly method comprises the following step: severing the clamping means, in particular severing the clamping means provided in the form of a strapping band. By severing the clamping means, in particular the strapping bands, the battery modules assembled to form the battery module assembly can be particularly easily separated from one another.

[0038] Short description of the characters

[0039] Preferred further embodiments of the invention are explained in more detail in the following description of the figures, each of which shows schematically:

[0040] Figure 1 shows a section of a module housing in a frontal sectional view;

[0041] Figure 2 shows a battery module comprising a module housing in a frontal sectional view;

[0042] Figure 3 shows a battery arrangement comprising several battery modules with a module housing in a frontal sectional view; and

[0043] Figure 4 shows a battery arrangement comprising several battery modules with a module housing in a plan view.

[0044] Detailed description of preferred embodiments

[0045] Preferred embodiments are described below with reference to the figures. Identical, similar, or equivalent elements in the different figures are provided with identical reference numerals, and a repeated description of these elements is partially omitted to avoid redundancies.

[0046] Figure 1 schematically shows a section of a module housing 1 of a battery module in a frontal sectional view. The module housing 1 comprises a housing wall 6, of which three housing sides are shown in Figure 1, namely a top side 6a, a bottom side 6b and a lateral side 6c. The housing wall 6 is made essentially of a carbon fiber reinforced plastic, CFRP. A large number of interconnected battery cells (not shown) are arranged within the module housing 1. The battery cells are in the form of round cells and are cooled by means of immersion cooling, so that an immersion fluid 16 flows around the battery cells. Due to the immersion cooling, an increased internal pressure P1 prevails within the module housing 1, more precisely within the housing wall 6, when the battery module is in an operating state, which is referred to as the operating pressure P1.In the present case, increased internal pressure means that the internal pressure is greater than an external ambient pressure, in particular greater to such an extent that the internal pressure would be able to bulge outwards, i.e. deform, a housing wall with low inherent rigidity.

[0047] In order to counteract the operating pressure P1, a counterpressure device 8 is mounted on the module housing 1, comprising a tensioning means 10 for providing a tensioning force F and a pressure means 12 for transmitting the tensioning force F to the housing wall 6. The tensioning means comprises at least one tensioning element 10a in the form of a strapping band 10a, as well as a closure 10b that closes the strapping band 10a so that it exerts the tensioning force F on the pressure means 12. In other words, the strapping band 10a has two ends (not shown) that are firmly connected to one another by means of the closure 10b, wherein a pretension in the form of a tensile stress prevailing within the strapping band 10a is provided.

[0048] Since the housing wall 6 is essentially made of a CFRP material, its inherent rigidity is so low that, without the counterpressure device 8, the operating pressure P1 would deform the housing wall 6, for example, the lateral side 6c, thus bulging it outward. Because the pressure medium 12 is arranged between the prestressed clamping device 10 and the housing wall 6, in Figure 1 the lateral side 6c, the prestress provides the clamping force F, which acts via the pressure medium 12 in the form of a counterpressure P2 on the outside of the housing wall, more precisely on the lateral side 6c.

[0049] The internal pressure P1 and the counterpressure P2 are represented in the present figures by arrows, the length of which roughly symbolizes the level of pressure. To be more precise, the different lengths of the pressure arrows shown do not strictly speaking illustrate a pressure curve along the housing wall 6, but rather a curve of a bending moment generated due to the respective pressure, which acts on the housing wall 6. For example, the centrally arranged arrow of the internal pressure P1, midway between the top side 6a and the bottom side 6b, has the greatest length among the group of arrows. However, the internal pressure P1 is essentially the same along the housing wall 6. The length of the arrow thus symbolizes the level of the bending moment resulting from the pressure, which acts on the corresponding side of the housing wall 6.Since the center of the side is at the greatest distance from the side edges 14 or the outer edges 14 of the housing, the lever for the applied pressure is greatest there, so the bending moment is greatest there. The above consideration applies analogously to a bending moment provided by the counterpressure P2.

[0050] Because the pressure element 12a in Figure 1 is arranged centrally on the lateral side 6a, the counterpressure P2, i.e., the counterbending moment, is greatest in the center. By appropriately adjusting the preload of the clamping device 10, the clamping force F can be adjusted so that the counterpressure P2, in terms of magnitude and profile (of the bending moment), just neutralizes the internal pressure P1 (or its bending moment). In this way, a housing wall 6 made of a lightweight material with low inherent rigidity can be used.

[0051] If a thin square tube 12a or a slender I-beam or double-T-beam is used as the pressure medium, the pressure medium can have a low mass, allowing a lightweight module housing 1 to be produced. The size of the pressure element 12a compared to the thickness of the housing wall is shown significantly disproportionately large in Figure 1 for illustrative purposes.

[0052] Figure 2 shows a battery module 2 comprising a module housing 1 in a frontal sectional view. The structure basically corresponds to the structure in Figure 1, so that only differences will be discussed below. The module housing 1 has an inner wall 6d which divides the module interior into two sub-chambers. At the same time, the inner wall 6d keeps the distance between the top side 6a and the bottom side 6b constant, so that the bending moment in the corresponding areas is negligible. Figure 2 shows a counter-pressure device 8 with six pressure elements 12a: one on each of the lateral sides 6c and one each on the top and bottom of the sub-chambers provided by the inner wall 6d. The internal pressures of the two sub-chambers acting on the inner wall 6d cancel each other out, so that there is no bending moment on the inner wall 6d.

[0053] Since the two lateral sides 6c are longer than the upper and lower sides 6a, b of the subspaces, the pressure means 12a on the lateral sides 6c are correspondingly larger than the pressure means 12a on the upper and lower sides 6a, b. As a result, the bending of the tensioning element 10a, i.e., the strapping band 10a, is greater on the lateral sides 6c than on the upper or lower sides 6a, b. Due to the greater bending of the strapping band 10a, the tensioning force F is correspondingly higher, and thus the counterpressure P2 or the bending moment. Thus, the counterpressure device 8 can be designed as required according to the expected bending moments due to the internal pressure P1.

[0054] Figure 3 shows a battery assembly comprising several battery modules with a module housing in a frontal sectional view, and Figure 4 shows a corresponding top view. For the sake of clarity, some of the arrows for the pressures are not shown. In the example according to Figure 3, four battery modules 2 are connected to form a vehicle battery 4. Accordingly, Figures 3 and 4 each show a battery module assembly 3, wherein the clamping device 10 encloses four module housings 1.

[0055] Furthermore, the top view of Figure 4 shows two variants of the pressure element 12a. On the left-hand side of Figure 4, a continuous pressure element 12a is shown, which extends from below the lower strapping band 10a to above the upper strapping band 10a. Accordingly, the pressure curve P2, or bending moment curve, of the counter-pressure device 8 is shown on the left. On the right-hand side of Figure 4, a pressure medium 12 with interruptions is shown. In other words, the pressure medium 12 on the right-hand side of Figure 4 comprises three individual pressure elements 12a. This can be advantageous in order to save material and thus weight, or to free up installation space for other components. The pressure arrows of the counter-moment device 8 on the right-hand side of Figure 4 illustrate that this variant of the pressure medium 12 also leads to a counter-pressure P2 provided as needed.

[0056] Furthermore, in Figure 4, the second, i.e., middle strapping band 10a is shown significantly wider than the lower or upper strapping band 10a. Accordingly, the pressure arrows P2 are shown longer. This illustrates that the middle strapping band 10a is provided with a higher pretension than the lower or upper strapping band 10a. In this way, a higher counterpressure P2 can be provided in the center as needed.

[0057] Where applicable, all individual features illustrated in the embodiments can be combined and / or interchanged without departing from the scope of the invention. For example, each individual printing element 12a in each example can be designed independently of another printing element 12a of the same example in terms of shape, size, and material.

[0058] 1 module housing

[0059] 2 battery module

[0060] 4 Battery

[0061] 6 Housing wall

[0062] 6a top

[0063] 6b bottom

[0064] 6c Lateral side

[0065] 6d interior wall

[0066] 8 Counterpressure device

[0067] 10 clamping devices

[0068] 10a Tensioning element, strapping band

[0069] 10b closure

[0070] 12 Pressure Means

[0071] 12a Pressure element

[0072] 14 Housing outer edge

[0073] 16 Immersion fluid

[0074] F clamping force

[0075] P1 operating pressure

[0076] P2 back pressure

Claims

Claims 1. Module housing (1) for a battery module (2) of a battery (4), in particular a vehicle battery, comprising a housing wall (6) which can be subjected to an operating pressure (P1) on the inside of the housing, and a counterpressure device (8) for counteracting the operating pressure (P1), which is designed to provide a counterpressure (P2) on the housing wall (6) on the outside of the housing, wherein the counterpressure device (8) has a clamping means (10) for providing a clamping force (F) and a pressure means (12) for transmitting the clamping force (F) to the housing wall (6), and wherein the pressure means (12) is arranged between the clamping means (10) and the housing wall (6) in an assembled state in order to transmit the clamping force (F) in the form of the counterpressure (P2) to the outside of the housing wall (6).

2. Module housing (1) according to claim 1, wherein the pressure means (12) is or can be fastened to the housing wall (6) on the outside of the housing.

3. Module housing according to claim 1 or 2, wherein the pressure medium (12) is tubular or rod-shaped.

4. Module housing (1) according to one of the preceding claims, wherein the pressure means (12) extends parallel to a housing outer edge (14), in particular extends parallel to two adjacent housing outer edges (14).

5. Module housing (1) according to one of the preceding claims, wherein the clamping means (10) encloses the housing wall (6), in particular completely encloses the circumference of the housing wall.

6. Module housing (1) according to one of the preceding claims, wherein the tensioning means (10) comprises a strapping band (10a).

7. Module housing (1) according to claim 6, wherein the strapping band (10a) has a thickness of 0.3 to 0.7 mm and a width of 8 to 25 mm.

8. Module housing (1) according to claim 6 or 7, wherein the strapping band (10a) is a steel band with a tensile strength in the range 800 to 1200 N / mm 2 and in particular wherein the strapping band (10a) in the assembled state has a band tension in the range 1000 to 8000 N.

9. Module housing (1) according to one of the preceding claims, wherein the housing wall (6) is formed substantially from a lightweight material, in particular wherein the housing wall comprises a fiber-reinforced plastic material, in particular a CFRP material.

10. Battery module (2) comprising the module housing (1) according to one of the preceding claims with the counterpressure device (8) in the assembled state, wherein the battery module (2) comprises an immersion fluid (16) for immersion cooling, wherein the immersion fluid (16) in an operating state applies the operating pressure (P1) to the housing wall (6) on the inside of the housing.

11. Battery module (2) according to claim 10, wherein the counterpressure device (8) is configured to provide the counterpressure (P2) on the housing wall (6) on the outside of the housing in order to counteract deformation of the housing wall when subjected to the operating pressure (P1).

12. Battery module (2) according to claim 10 or 11, wherein the clamping means (10) has a plurality of clamping elements (10a).

13. Battery module (2) according to one of claims 10-12, wherein the pressure means (12) comprises a plurality of pressure elements (12a).

14. Battery module arrangement (3) comprising at least two battery modules (2) according to claim 10 or 11, wherein the clamping means (10) encloses at least two module housings (1).

15. A method for producing a battery module arrangement (3) comprising at least two battery modules (2), comprising the steps: - positioning the at least two battery modules (2) such that the at least two battery modules are arranged adjacent to one another; - Mounting a counterpressure device (8) on the adjacently positioned battery modules (2), comprising: -- Attaching a pressure means (12) to a housing wall (6) of at least one of the battery modules (2) for transmitting a clamping force (F) to the housing wall (6) and -- Attaching a clamping means (10) for providing the clamping force (F), so that the pressure means (12) in an assembled state is between the clamping means (10) and the Housing wall (6) is arranged in order to transmit the clamping force (F) in the form of a counterpressure (P2) to the outside of the housing wall (6).

16. A method for disassembling a battery assembly (3) produced by the method according to claim 15, comprising: - cutting through the clamping means (10), in particular cutting through the clamping means (10) in the form of a strapping band (10a) provided tensioning device (10).

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