The disclosure relates to a module housing assembly for accommodating at least one battery cell, wherein the module housing assembly has a module housing with a housing base, which delimits a receiving area for accommodating the at least one battery cell in a first direction, and two side plates, which delimit the receiving area on both sides in a second direction. Furthermore, the disclosure also relates to a battery module with such a module housing assembly and a method for clamping a battery module.
Current battery modules or the housings thereof are made from a plurality of components and connected to one another. Such a module housing often has two side plates, which are also referred to as end plates, and which delimit a cell stack in the longitudinal extension direction thereof with several battery cells arranged next to one another in a longitudinal extension direction. These end plates are usually clamped together by a clamping mechanism, for example with so-called side binders, i.e. side parts that extend on both sides of the cell stack in the longitudinal extension direction thereof and connect the end plates to one another under tension. These side binders usually have a chamfer on the upper edge so that the cells do not fall out of the module when subjected to loads in the z-direction. The z-direction usually defines a direction from a module lower side to the module upper side, wherein the terminals of the battery cells typically are arranged on the upper sides thereof if there is a cooling device on the module lower side. The housing base of such a battery module is often provided by an overall battery base for all battery modules accommodated in a high-voltage battery and not separately for each battery module. In other words, a module housing, as it is typically designed, can merely be understood as a bottomless frame. The battery modules can then be used in an overall battery housing with a cooling base. For the thermal connection to the cooling base, a so-called gap filler is usually introduced between the module lower sides and the cooling base, which gap filler can be provided, for example, as a heat-conducting compound or heat-conducting paste.
This large number of parts has clear disadvantages in terms of preloading the cells, since the forces often cannot be optimally dissipated and the structures are not as stiff as would be ideal. In addition, numerous work steps are necessary in assembly, in which individual parts must be joined together, for example by welding.
EP 3 678 208 A1 describes a battery module with several battery cells which are arranged in a horizontal direction, wherein a dimension of the battery module is greater in the horizontal direction than in the vertical direction. The cells of such a battery module can be held together by one or more binding straps.
Furthermore, CN 210723151 U describes a steel strap for enclosing a cell stack with several battery cells, wherein screw sleeves are also arranged on the steel strap, into which sleeves screws can be inserted, by means of which such a battery module can be screwed to a battery housing.
So far, it has not been possible with the battery modules disclosed in the prior art to efficiently provide functions such as the connection to a cooling device, clamping of the battery cells, a high degree of stability, and the provision of support in the z-direction.
The object of the present disclosure is therefore to provide a module housing assembly, a battery module, and a method that allow a battery module to be designed as simply and efficiently as possible, and in particular enable a connection to cooling and clamping in the simplest and most efficient manner possible.
This object is achieved by a module housing assembly, a battery module, and a method with the features according to the respective independent claims. Advantageous embodiments of the disclosure are the subject matter of the dependent claims, the description, and the figures.
A module housing assembly according to the disclosure for accommodating at least one battery cell has a module housing, which in turn comprises a housing base, which delimits a receiving area for accommodating the at least one battery cell in a first direction, and two side plates, which delimit the receiving area on both sides in a second direction. In addition, the module housing assembly comprises a retaining element for arrangement on the at least one battery cell accommodated in the receiving area, so that at least a first part of the retaining element delimits the receiving area in the first direction on a side of the receiving area opposite the housing base. In addition, the module housing assembly comprises a clamping device, which extends at least from a first of the side plates to a second of the side plates on a side of the receiving area opposite the housing base, wherein the clamping device is designed in such a way that the clamping device can exert a force onto the retaining element in the direction of the housing base if said retaining element is arranged on the at least one battery cell arranged in the receiving area.
A module housing can therefore be provided which is U-shaped, for example, and in which the at least one battery cell, in particular also several battery cells in the form of a cell stack, can be accommodated. If such at least one battery cell is accommodated in this module housing, the tensioning strap extends at least on the side opposite the housing base and, in doing so, presses the retaining element arranged on the at least one battery cell downwards in the direction of the housing base. Such a clamping device can thus advantageously provide a clamping of such a battery module, on the one hand, and a pressing force in the direction of the housing base can simultaneously be generated by clamping the retaining element between this clamping device and the at least one battery cell. This in turn advantageously allows the housing base to be in the form of a cooling base, for example, or to be connected to a cooling device. In this case, for example, the gap filler mentioned at the outset between the at least one battery cell and the housing base can be dispensed with entirely, since the described pressing force, which can be provided by the combination of the retaining element and the clamping device, efficiently presses the at least one battery cell against the housing base. This makes it possible to provide significantly more efficient heat dissipation. The fact that a module free of gap filler can be provided in this way means that enormous costs and weight can be saved. The manufacturing effort is also reduced enormously as a result. The downward clamping force generated by the clamping device and the retaining element not only enables a good thermal connection to the housing base in an efficient manner, but the retaining element also simultaneously acts as a hold-down device or retaining element in the z-direction, which corresponds to the first direction mentioned above and which preferably extends parallel to the vertical direction of the vehicle, when the module housing assembly is arranged as intended in a motor vehicle. Because the module housing also comprises a housing base that is specifically assigned to the battery module and is arranged directly on the side plates, battery modules can be built much more rigidly, since the two side plates and the housing base form a structural unit, in particular a fixed unit. If the at least one battery cell is accommodated in the receiving area of the module housing assembly, a battery module is provided which, for example, can be used together with other battery modules constructed in this way in an overall battery housing or a frame or a housing trough. The base of such a trough then does not have to be in the form of a cooling base, and it is preferably not in this form either. In addition, the side binders described at the outset, i.e. the side parts, can also be dispensed with. Overall, numerous components can be saved in this way, fewer components have to be joined and assembled in production, and above all the connection to a cooling device can be provided much more efficiently and easily, in particular without the need to provide a gap filler, although it is still possible to provide a gap filler, for example in the form of a curable heat-conducting compound or heat-conducting adhesive, between the at least one battery cell accommodated in the receiving area and the housing base.
The receiving area can be designed in such a way that it is intended to receive only a single battery cell. However, the receiving area is preferably designed in such a way that it can accommodate several battery cells therein, in particular prismatic battery cells. The receiving area can therefore have an essentially cuboid geometry. The several battery cells can be provided in the form of a cell stack and can accordingly be arranged next to one another in a longitudinal extension direction of such a cell stack. This is especially advantageous when the several battery cells are designed, for example, as prismatic battery cells, since this enables an especially compact construction. In addition, the battery cells can be provided as lithium-ion cells, for example. If such a cell stack is accommodated as intended in the receiving area of the module housing assembly, the longitudinal extension direction of the cell stack corresponds to the second direction. Incidentally, the second direction can be oriented perpendicularly to the first direction. The side plates thus function as end plates, which delimit the cell stack in the longitudinal extension direction thereof and via which the cell stack can be clamped, in particular in the second direction. The clamping is also accomplished via the clamping device. The clamping device can be arranged in such a way that it connects at least the two side plates to one another. For example, it can be arranged in such a way that it extends from one side plate to the other side plate and, by means of the clamping force provided by the clamping device, clamps the two side plates together parallel to the second direction. Consequently, a corresponding clamping force can be applied to the cell stack in or opposite the second direction via the side plates, and at the same time a pressing force can be applied, opposite the first direction, to the cells or the cell stack via the retaining element, i.e. in the direction of the housing base. However, the clamping device can also be designed in such a way that it completely encircles the module housing and, for example, also extends on the outside along the housing base in the direction of the second direction. In addition, it is also conceivable that not only one such clamping device is provided per battery module, but also, for example, two or more than two clamping devices extending parallel to one another, which press the same retaining element in the direction of the cell stack and in the direction of the housing base. In addition, it is also conceivable that not only one retaining element is provided, but also several, which can be arranged, for example, extending parallel to one another in the second direction on the at least one battery cell.
In its intended arrangement, a battery cell is preferably arranged in the receiving area in such a way that the terminals thereof are arranged on a side opposite the housing base. The side of the at least one battery cell with the terminals is defined as an upper side of the at least one battery cell in this case. The retaining element is preferably arranged on the upper side of the at least one battery cell when it is located in the receiving area of the module housing assembly. The retaining element can be arranged extending on the terminals or in an area of the upper side of the at least one battery cell between the terminals. The support surface of the retaining element is preferably flat on the side facing the cell stack.
In this case, the retaining element can also extend in a third direction, which is perpendicular to the first and second direction, over the entire width of an upper side of a battery cell or only over part of this upper side in the third direction. The second variant is preferred because it can be implemented in a significantly simpler and more space-efficient manner.
According to a very advantageous embodiment of the disclosure, the housing base is designed as a cooling base. For example, a cooling medium can flow through the housing base. For this purpose, the housing base can be designed with cooling channels through which such a cooling medium can flow. This advantageously allows module cooling to be integrated into a battery module. A complex connection of a battery module to a cooling base of an overall battery housing is therefore no longer necessary.
In a further very advantageous embodiment of the disclosure, the retaining element has a thickness in the first direction which varies along the second direction, in particular which decreases in the direction of the respective side plates starting from a center of the retaining element with respect to the second direction. This can be achieved, for example, in that an upper side of the retaining element facing the clamping device, when this is located on the at least one battery cell arranged in the receiving area, is curved with respect to the second direction, in particular arched and/or monotonically curved. In this way, an especially homogeneous pressing force can be provided in the second direction. This is especially advantageous when several battery cells are accommodated in the receiving area in the form of a cell stack. If the retaining element were instead designed, for example, as a block or cuboid or plate with a constant thickness in the second direction, a higher pressing force in the direction of the housing base would act on those battery cells that are arranged closer to the side plates. This effect can advantageously be compensated precisely by the fact that the retaining element increases in thickness, starting from the side plates in the direction of the center thereof with respect to the second direction. In other words, the thickness of the retaining element is maximum in the center with respect to the second direction. For example, the maximum thickness may be 1 centimeter to 2 centimeters or less than 1 centimeter. In the third direction, however, the thickness of the retaining element preferably does not vary. A uniform pressing force can thus also be provided in the third direction. Optionally, a type of guide groove extending in the second direction can be provided for the clamping device.
In principle, the retaining element can be provided, for example, as a type of block, the thickness of which varies in the longitudinal direction, that is to say in the second direction, for example in the form of an arc-shaped block. However, the side of the retaining element facing the at least one battery cell is preferably of planar design or has a geometry which is adapted, for example is complementary, to a geometry of an upper side of the at least one battery cell. A pressure distribution that is as uniform as possible can thus be provided on the upper side of the at least one battery cell.
Furthermore, it is advantageous if the retaining element extends from the first side plate to the second side plate. If, for example, a cell stack with several battery cells is arranged in the receiving area, then it is preferable for the retaining element to extend over all upper sides of the respective battery cells at the same time. In principle, the retaining element can also be at a certain distance from the side plates, or the retaining element can also have contact with the side plates.
It is also especially advantageous if the retaining element, as is provided according to a further embodiment of the disclosure, has two side tabs which adjoin the first part of the retaining element on both sides in the second direction and extend in the direction of the housing base and which, when the at least one battery cell is accommodated in the receiving area, are each arranged between the at least one battery cell and one of the respective side plates. In other words, these two side tabs can be clamped between the cell stack and the respective side plates. The clamping force with respect to the second direction is additionally achieved by the clamping device. As a result, more stability can be provided with regard to the positioning of the retaining element. Thus, to a certain extent, a movement of the at least one battery cell in the z-direction, i.e. in the first direction, can additionally be prevented by the adhesion generated thereby.
In principle, the retaining element can be made from any desired material, for example plastic, aluminum, wood, or the like. It is especially advantageous if the retaining element comprises a metal and/or a plastic and/or is provided as a hybrid component. Such a hybrid component can comprise both soft components and hard components and, for example, also combine a metallic part with a plastic part or plastic parts of different hardness levels. In addition, it is especially advantageous if the retaining element has an at least partially elastic component, which can be provided simply by a hybrid component, for example. In this case, a damping effect can be provided by such an at least partially elastic component. In this way, external forces acting on the battery module can be especially gently damped.
In a further advantageous embodiment of the disclosure, the clamping device is designed as at least one tensioning strap. Such a tensioning strap can be tensioned around the module housing with the cell stack accommodated in the receiving area in an especially simple manner. In addition, such a tensioning strap can also be provided in a simple and cost-effective manner. For example, it can be provided as tape, for example. There are also different options for the material. For example, the at least one tensioning strap can have a fiber-reinforced plastic, for example made of a glass-fiber-reinforced plastic or carbon-fiber-reinforced plastic, and/or a carbon-fiber strap or be designed as such, and/or a metal or be designed as a metal strap, such as a steel strap, aluminum strap, and so on. It is especially advantageous if the tensioning strap comprises a carbon-fiber strap or is designed as such. This offers a high degree of stability and flexibility at the same time. This is also especially advantageous when combined with a plastic housing, as will be explained in more detail later. However, a high degree of stability can also be provided by a metal strap. In addition, metal has the advantage that it is heat-resistant and can easily withstand the high clamping forces.
In a further advantageous embodiment of the disclosure, the module housing is formed at least for the most part from a plastic, in particular a fiber-reinforced plastic, and/or comprises a metal or an alloy. It is especially advantageous, above all, if the housing is provided as a plastic housing, for example made of a fiber-reinforced plastic, and is in particular designed in one piece. In other words, the housing base and the side plates can be manufactured as a plastic component, for example by means of an injection-molding process. Nevertheless, the housing base and side plates may also be provided as separate plastic components that are bonded together, e.g. welded together, as a strap assembly. The formation of the side plates in particular from plastic also enables an especially advantageous attachment of the tensioning strap, in particular if it is also made of plastic or is provided as a carbon strap. It is particularly advantageous if the tensioning strap also has two strap ends which are attached to at least one of the side plates, in particular into which at least one of the side plates, which is largely made of a plastic, is partially cast. For example, a groove extending in the third direction can be provided on one of the side plates, in which one or two eyelets are also provided for passing through the two tensioning strap ends, in order to clamp the tensioning strap after the at least one battery cell has been accommodated in the receiving area. In the tensioned state, the eyelets can then be filled with plastic in an injection-molding process, for example, whereby the tensioning strap ends are finally attached to the one side plate. This establishes an especially stable connection between the tensioning strap and the side plate. This also enables an especially simple clamping. For example, if the eyelets are oriented at an angle to the direction of rotation of the strap, for example of 45 degrees, it is possible to clamp the tensioning strap by tensioning the ends in and opposite the third direction, i.e. perpendicular to the first direction. Alternatively, the tensioning strap ends could also be fastened to one another in an overlapping manner. A form-fitting or material-fitting attachment to the side plate is then not required. However, the clamping of the tensioning strap is somewhat more difficult here than in the previously described variant.
If the module housing is made of a metal or an alloy, for example aluminum, it can also be provided that another fastening mechanism, for example rivets or welding or the like, is used to fasten the tensioning strap to the side plate.
In a further advantageous embodiment of the disclosure, the clamping device and/or the retaining element has at least one releasable passage opening assigned to a releasable degassing opening of the at least one battery cell, which passage opening is arranged in the first direction above the degassing opening of the at least one battery cell, in particular when the at least one battery cell is accommodated in the receiving area. Battery cells typically have releasable degassing openings, for example in the form of a bursting membrane, which is often arranged on the upper side of such a battery cell between the terminals. Such a releasable degassing opening makes it possible for gases emerging from the battery cell to be discharged from the battery cell in a targeted manner in an emergency, for example in case of a thermal event, without the battery cell exploding in the process.
Precisely when the retaining element is arranged on these degassing openings above the battery cells, it is advantageous if such an at least releasable degassing opening or passage opening is also provided in the retaining element and/or in the overlying tensioning strap. Specifically a tensioning strap can also provide such a releasable degassing opening, for example, simply as a type of predetermined breaking point, for example as a material weakening, perforation, or the like, which ruptures as soon as gas escapes from the at least one battery cell. Optionally, gas-routing channels integrated into the retaining element can also be provided to direct the gas flow that escapes from the battery cells. Gas escaping from the battery cells can be routed out of the battery module and in particular out of the entire battery through the battery gas-routing channels, for example in or opposite the second direction and/or in or opposite the third direction.
Furthermore, the disclosure also relates to a battery module with a battery module assembly according to the disclosure or one of the embodiments thereof. The advantages described for the module housing assembly according to the disclosure apply in the same way to the battery module according to the disclosure. In addition to the module housing assembly, the battery module can also have at least one battery cell accommodated in the receiving area. The battery module preferably comprises a cell stack with several battery cells arranged next to one another in the second direction and arranged in the receiving area. These can be designed as described above.
A motor vehicle with a module housing assembly according to the disclosure or a battery module according to the disclosure or one of the embodiments thereof should also be regarded as part of the disclosure.
If such a battery module is installed in the motor vehicle, then the first direction preferably corresponds to the vertical direction of the vehicle. The second direction and the third direction can then correspond, for example, to the longitudinal direction of the vehicle and to the transverse direction of the vehicle, or vice versa.
The disclosure also relates to a method for clamping a battery module, which has a module housing assembly that comprises a module housing with a housing base, which delimits a receiving area for accommodating at least one battery cell in a first direction, and two side plates, which delimit the receiving area on both sides in a second direction. A retaining element is arranged on the at least one battery cell, so that when the at least one battery cell is arranged in the receiving area, at least a first part of the retaining element delimits the receiving area in the first direction on a side of the receiving area opposite the housing base. In addition, a clamping device is provided, which extends at least from a first of the side plates to a second of the side plates on a side of the receiving area opposite the housing base, and which is clamped in such a way that a force is applied to the retaining element in the direction of the housing base by means of the clamping device, if the retaining element is arranged on the at least one battery cell arranged in the receiving area.
The advantages described for the module housing assembly according to the disclosure and the embodiments thereof also apply in the same manner to the method according to the disclosure.
The disclosure also comprises refinements of the method according to the disclosure, which have features as already described in the context of the refinements of the module housing assembly according to the disclosure. For this reason, the corresponding refinements of the method according to the disclosure are not described again here.
The motor vehicle according to the disclosure is preferably designed as an automobile, in particular as a passenger car or truck, or as a passenger bus or motorcycle.
The disclosure also comprises combinations of the features of the described embodiments. The disclosure thus also comprises implementations that each have a combination of the features of several of the described embodiments, provided that the embodiments were not described as being mutually exclusive.
Exemplary embodiments of the disclosure are described hereinafter. The following is shown:
The exemplary embodiments explained hereinafter are preferred embodiments of the disclosure. In the exemplary embodiments, the described components of the embodiments each represent individual features of the disclosure to be considered independently of one another, which each also refine the disclosure independently of one another. Therefore, the disclosure is also intended to comprise combinations of the features of the embodiments other than those shown. Furthermore, the described embodiments can also be supplemented by further ones of the above-described features of the disclosure.
In the figures, the same reference signs designate elements that have the same function.
These disadvantages can now be advantageously avoided by the disclosure or the embodiments thereof.
Since this tape 44 extends above the battery cells 46 in combination with the retaining element 48, the cells 46 can be prevented from lifting off in the z-direction. However, it is especially advantageous that this tensioning strap 44, in combination with the retaining element 48, which provides a hold-down device, can also be used to exert a pressing force downwards on the battery cells 46, opposite the z-direction, in the direction of the housing base 36. This pressing force on the respective cells 46 is denoted by F in the present case. This results from an initial force F0,which is exerted on the hold-down devices 48 via the tensioning strap 44. Furthermore, the retaining element 48 has a thickness d in the z-direction, which varies in the x-direction. In particular, the retaining element 48 is thicker in the center 52 thereof with respect to the x-direction than in the edge region 54 near the side plates 38. The retaining element 48 therefore has a different wall thickness on the outside 54 than in the center 52 of the component 48. This makes it possible for the pressing forces F to be distributed almost homogeneously on the cells 46 over the entire x-direction. These can thus advantageously be pressed evenly against the cooling base 36. As a result of these pressing forces F, a gap filler between the cells 46 and the cooling base 36 can also be dispensed with. This allows a significantly more efficient connection to the cooling base 36. Since a base 36 is integrated into the module 30, which base serves as a cooling base 36 at the same time, advantageously no further effort is required for gap fillers or bases integrated into the battery housing. In addition, crash structures 56 can also be easily integrated into the base 36, which can be accomplished especially easily if the base 36 or the housing 34 is made of plastic. In the present example, these crash structures 56 are shown only schematically with dashed lines. These structures can be provided, for example, as a kind of edge or protruding elevation relative to the base plane of the housing base 36.
The pressure F on the cells 46 can be set opposite the z-direction by means of the tensioning force of the tensioning strap 44 in combination with the variable thickness d of the retaining element 48. The retaining element 48 coupled to the tensioning strap 44 thus advantageously allows an additional compressive force from the tensile force of the strap 44 to be applied to the cells 46.
If the tape 44 extends between the terminals of the battery cells 46, which can be arranged on the respective upper sides 46a of the battery cells 46 (see
Overall, the examples show how the disclosure can provide a retaining element in the z-direction, which allows efficient formation of a battery module with a retaining element, which in turn contains or provides a homogeneous load distribution due to the deformation or geometry of the retaining element. The entire module can be made of plastic and designed to be highly integrated. Such a module can be significantly lighter, since tapes acting as a tensioning strap are very light. Overall, a cost saving of 10 to 15 percent can be achieved. Above all, the provision of a significantly simpler module housing without costly cooling is made possible as well as a module completely free of gap filler.
Number | Date | Country | Kind |
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102021118396.0 | Jul 2021 | DE | national |