Battery, method for mounting a battery, and motor vehicle
Patent Information
- Application Number
- EP2024701097
- Authority / Receiving Office
- EP · EP
- Patent Type
- Applications
- Current Assignee / Owner
- Priority Date
- 2023-02-17
- Filing Date
- 2024-01-09
- Publication Date
- 2025-12-24
AI Technical Summary
Existing battery modules are rigid, large, and heavy due to structural casting and require extensive thermally conductive adhesive to compensate for manufacturing tolerances, leading to complex assembly and inefficient heat transfer.
Incorporating an elastic, flexible sealing tape between battery cells to absorb thickness changes during charging and discharging, allowing movement and maintaining a defined distance, along with a thermal barrier and removable alignment elements, which reduces the need for heavy end plates and excessive adhesive, enabling a lightweight and efficient structure with improved heat conduction.
The solution results in a compact, lightweight battery with enhanced thermal connection and extended service life, as the flexible sealing tape compensates for manufacturing tolerances and allows for better heat dissipation with reduced adhesive usage.
Smart Images
Figure EP2024050364_22082024_PF_FP
Abstract
Description
[0001] Battery, method for assembling a battery and motor vehicle
[0002] The invention relates to a battery of the type defined in more detail in the preamble of claim 1. Furthermore, the invention relates to a method for assembling such a battery. The invention also relates to a motor vehicle having such a battery.
[0003] Batteries with a housing and at least one battery module are known from the prior art. For example, DE 102016213138 A1 and DE 102008 010 828 A1 describe various individual battery cells that can be combined into a module, which can then be inserted into a housing as a composite of individual battery cells. Such a module as a composite of individual battery cells is described, for example, in DE 102008 010 824 A1.
[0004] The typical design, familiar to those skilled in the art, provides for the individual battery cells to be assembled into the module, for example, using the clamping elements and typically end plates shown in the cited document, and then inserted into a housing. For fastening and mechanical securing, this module can be fixed in the housing using structural encapsulation. The module itself can then have its own cooling plate, as described in the cited document, or, as has become established in the general state of the art, can be bonded to a base surface of the housing using a thermally conductive adhesive, which in turn is cooled.
[0005] In practice, this presents the disadvantage that these modules are relatively rigid, large, and heavy. Furthermore, any tolerances in the battery housing, which is often constructed from thin sheet metal, must be compensated for using the thermally conductive adhesive. Ultimately, all of the individual battery cells rigidly installed in the module assembly are in thermally conductive contact with the housing's base, which has a comparatively high tolerance regarding flatness.
[0006] Ultimately, this leads to comparatively complex assembly and an unnecessarily heavy and large battery.
[0007] The object of the present invention is to avoid these disadvantages and to provide an improved battery with the features in the preamble of claim 1. Furthermore, the object of the present invention is to provide an improved assembly method and a motor vehicle with such a battery.
[0008] According to the invention, this object is achieved by a battery having the features in claim 1, and in particular in the characterizing part of claim 1. Furthermore, a method according to claim 9 and a motor vehicle according to claim 10 solve the problem.
[0009] In the battery according to the invention, the assembly of individual battery cells has an elastic, flexible sealing band between the stacked individual battery cells, by means of which the side surfaces of adjacent individual battery cells are held at a distance from one another. This makes it possible, on the one hand, to compensate for tolerances via the elastic, flexible sealing band and to enable movement of the individual battery cells in the stacking direction on the one hand, as well as transversely to the stacking direction on the other. The elastic, flexible sealing band thus lies between the individual battery cells and holds them at a defined distance from one another, so that any change in the thickness of the individual battery cells during charging and discharging can be absorbed by the elasticity of the sealing band.The elastic sealing strip also ensures that no structural encapsulation material can penetrate the area between the individual battery cells in the stacking direction, which could impair the free movement of the individual battery cells due to changes in thickness, the so-called "breathing" of the individual battery cells. This alone results in an improved structure with good performance and an extended service life of the individual battery cells. Furthermore, the elastic, flexible sealing strip also allows a certain degree of flexibility transverse to the stacking direction, so that the individual battery cells can, for example, sink onto a not completely flat base plate of a housing.This allows a good thermally conductive connection to be achieved with a comparatively small amount of thermally conductive adhesive and a small distance between the individual battery cells and the base plate, even with correspondingly large manufacturing tolerances of the base plate.
[0010] The sealing tape itself can be made of individual sheets or of endless tape folded back and forth in a Z shape between the individual battery cells.
[0011] According to a highly advantageous embodiment of the battery according to the invention, the sealing strip can have a thermal barrier. Such a thermal barrier in the sealing strip can ensure that thermal influences on neighboring individual battery cells are prevented, which is particularly advantageous if one of the individual battery cells experiences thermal runaway, i.e., overheats due to a fault. A thermal barrier integrated into the sealing strip can minimize the impact on the neighboring individual battery cells.
[0012] The assembly itself can comprise at least one detachable or removable alignment element with spacers extending between the individual battery cells. Such a removable alignment element can, for example, be arranged transversely to the stacking direction on the right and left sides of the assembly or stack of individual battery cells to ensure a defined thickness of the elastic sealing strip when stacking over the spacers.
[0013] According to a further very advantageous embodiment, the composite can also have a fixing aid. In particular, the alignment element and fixing aid can be used together so that the composite of the individual battery cells is stacked accordingly with a sealing tape placed between them, wherein a defined mechanical spacing between the individual battery cells and thus a defined mechanical size of the composite is realized via the at least one alignment element and its spacers. It can then be fixed accordingly with at least one fixing aid, after which the alignment element can be removed. The fixing aid can comprise an adhesive tape that is flexible in a height direction transverse to the stacking direction of the composite or can be designed as such. In particular, the fixing aid is designed to absorb forces in the stacking direction.The fixing aid can also comprise reinforcing fibers, for example, an adhesive tape provided with reinforcing fibers such as glass fibers, natural fibers, Kevlar fibers, carbon fibers, or the like. In particular, its extension in the vertical direction is relatively small, thus creating a certain degree of flexibility in this direction. In particular, several thin strips of adhesive tape can be arranged adjacent to each other in the vertical direction but spaced apart from each other.
[0014] An alternative could also be to combine the fixing aid and the alignment element accordingly, so that the latter, for example, consists of a type of bubble wrap, with the bubbles forming the spacers and the bubble wrap being wrapped around the composite to fix it accordingly.
[0015] The assembly of the individual battery cells, which is held together at least by the fixing aid and has the elastic sealing band between the individual battery cells, optionally with a thermal barrier therein, is correspondingly simple and efficient in its construction and can in particular completely dispense with the heavy end plates and, unlike the structures in the prior art, achieves the possibility of the individual battery cells lowering onto the housing base after being inserted into a housing due to the described flexibility in the height direction.
[0016] In the battery, this composite can then be fixed as a structural casting using a suitable casting compound, whereby this structural casting can, according to a very advantageous further development, comprise polyurethane or consist of a polyurethane material.
[0017] The method according to the invention for assembling a battery in one of the described embodiments provides that the assembly of individual battery cells is stacked with an intermediate sealing tape, maintaining a predetermined spacing between the individual battery cells, and is fixed along the stacking direction. A thermally conductive adhesive is then applied to a first inner surface of the housing, in particular its base surface, after which the assembly is inserted into the housing in such a way that its stacking direction extends parallel to the first inner surface. The individual battery cells of the assembly can then be moved individually toward the first inner surface.If the first inner surface is designed as the base of the battery housing, as described above, and is positioned at the bottom during assembly, this movement will occur automatically due to gravity, so that the individual battery cells will automatically lower toward the first inner surface. Regardless of the exact design of this inner surface, for which rather coarse manufacturing tolerances can typically be applied, the distance between the individual battery cells of the assembly and this first inner surface is minimized in every case, so that a relatively small amount of thermally conductive adhesive can be used to ensure a good bond between the individual battery cells and this inner surface, which is then cooled.In addition to the pure saving of adhesive and mass during assembly of the battery, this also has the decisive advantage that the cooling of the individual battery cells becomes more homogeneous and better, since a significantly better thermal connection to the corresponding inner surface can be achieved by using the thinnest possible layers of thermally conductive adhesive than if relatively thick and possibly relatively different amounts of thermally conductive adhesive are arranged between the respective individual battery cell and the first inner surface of the housing.
[0018] At the end of the assembly process, the composite is then fixed in the housing by means of a potting compound, as is already known in principle from the state of the art.
[0019] Such a battery is ideal for a variety of applications. The design and assembly method are suitable, among other things, for single battery cells using lithium-ion technology, and in particular for prismatic single battery cells, which are constructed without a frame or similar between the individual battery cells, so that the assembly consists only of the individual battery cells, the sealing tape, and the fixing aid. Such a battery can be constructed in a compact and lightweight manner, as elements such as module end plates, heavy tension anchors, and the like are dispensed with. At the same time, the thermally conductive connection to the housing is improved, as already described above.In addition to the general use of such a battery, it is now particularly suitable for use in vehicles, since a small overall volume, low weight, and a correspondingly high battery capacity per unit of volume or weight are crucial advantages. A motor vehicle according to the invention therefore provides for the use of such a battery, which is electrically coupled to its at least partially electrically driven drive train.
[0020] Further advantageous embodiments of the battery according to the invention and of the manufacturing method also emerge from the exemplary embodiment, which is described in more detail below with reference to the figures.
[0021] Showing:
[0022] Fig. 1 shows a battery in an embodiment according to the prior art;
[0023] Fig. 2 shows the basic structure of a battery assembly in a possible embodiment for a battery according to the invention;
[0024] Fig. 3 the composite according to Fig. 2 with alignment elements in a side view;
[0025] Fig. 4 shows the representation according to Fig. 3 in a plan view;
[0026] Fig. 5 is a schematic representation of an alternative embodiment of an alignment element;
[0027] Fig. 6 shows the composite according to Fig. 3 with additional fixing aids;
[0028] Fig. 7 shows the introduction of the composite according to Fig. 6 into a battery housing; and
[0029] Fig. 8 shows a battery analogous to the representation in Fig. 1 in an embodiment according to the invention.
[0030] The illustration in Figure 1 shows a battery designated 1 in a structure according to the prior art. This battery essentially consists of a battery housing designated 2, which is constructed from side walls 2.1 and a base plate 2.2. A battery module 3 is then inserted into this battery housing 2. This battery module consists of several prismatic individual battery cells 4, which are stacked in a stacking direction S with frame elements 5 in between. The module 3 is firmly clamped between two module end plates 6 via clamping elements, which are not visible here, and forms a mechanically rigid unit in which the individual battery cells 4 are positioned at their predetermined location. The individual battery cells 4 are fixed within the module 3 and, if applicable, the module 3 within the battery housing 2 via a structural encapsulation 7, with a structural encapsulation 8 being arranged between the base plate 2.2 and the individual battery cells 4, in order to thermally connect the individual battery cells to the cooled base plate 2.2. Due to the comparatively large manufacturing tolerances of the housing 2 and its base plate 2.2, a very large amount of thermally conductive adhesive 8 is required in some places in order to connect all of the individual battery cells 4 accordingly and to compensate for the tolerances of the base plate 2.2 compared to the rigid module 3 of the individual battery cells 4. In addition to the additional weight and installation space required by this thick layer of thermally conductive adhesive 8, this also ensures that the thermal connection of those individual battery cells 4 that are comparatively far apart from the base plate 2.2 is not as good as that of those individual battery cells 4 that are only far apart from the base plate 2.2.
[0031] The illustration in Figure 2 now shows a composite 11 of individual battery cells 4, which consists of the individual battery cells 4 stacked in the stacking direction S and a flexible sealing strip 12 arranged between them. This flexible sealing strip 12 can optionally comprise a thermal barrier 13, which is shown here between the individual battery cells, but not at the end of the stack in the sealing strip 12. Thanks to its flexibility, this sealing strip 12 now allows the stack to be mobile both in the stacking direction S, when the individual battery cells 4 expand and contract in this direction during charging and discharging, and in particular also to be flexible transversely thereto, in particular in a height direction designated here by H, wherein this flexibility is also present analogously in a width direction, which is perpendicular to both the stacking direction and the height direction.
[0032] This composite 11 of individual battery cells 4 is now, as can be seen in the illustration in Figures 3 and 4, positioned using alignment elements 14 with a defined distance between the individual battery cells 4. The flexible elastic sealing band 12 is located between the individual battery cells 4, which could also have the thermal barrier 13 here, although this is not shown in Figures 3 ff. to simplify the illustration. The plan view in Figure 4 shows individual spacers 15 of the alignment elements 14, which protrude between the individual battery cells and thus define the distance and ultimately the thickness of the elastic sealing band 12 present in the composite 11.Instead of using rigid alignment aids 14, which can be removed from the assembly 11 again during the further course of assembly, the use of a dimpled film, which is inserted via a roller 16 shown in Figure 5, would also be conceivable. The alignment element would then consist of a type of dimpled film, which, however, enables a substantially comparable function to the rigid alignment elements 14.
[0033] The illustration in Figure 6 takes up the illustration in Figure 3 again. The two alignment elements 14 can be seen here, which hold the individual battery cells 4 of the assembly 11 at their predetermined distance. In addition, three fixing aids 17 can be seen between the two alignment elements 14 and adjacent to them above and below in the height direction H. These fixing aids 17 serve to absorb forces, in particular in the stacking direction S, and to enable the greatest possible flexibility in the height direction H. The alignment aids therefore preferably consist of adhesive tapes which have a comparatively small width in the height direction H and which are preferably reinforced by glass fibers or other types of fibers in the stacking direction S. After the attachment of these fixing aids 17, a manageable assembly 11 is created, the alignment elements of which can be removed.When using a dimpled film as alignment elements 14, the film can simultaneously form the fixing aid 17, but this does not have to be the case.
[0034] This composite 11 can now, as can be seen in the illustration in Figure 7, be inserted from above in the height direction H into the housing 2 of a battery 10 according to the invention. Due to the flexibility of the fixing aids 17 on the one hand and of the elastic sealing strip 12 on the other hand in the height direction H, the individual battery cells 4 can now lower onto the base plate 2.2 of the housing 2 and thus ensure a comparatively good thermal connection with the minimum necessary amount of thermally conductive adhesive 8 between the base plate 2.2 and the respective individual battery cell 4. This deliberate allowance of lowering in the height direction H thus enables an improved thermal connection without the need for an expensive increase in the manufacturing tolerances of the base plate 2.2.By saving large quantities of thermally conductive adhesive 8 and by saving the module end plates 6 customary in the prior art as well as the tension anchors connecting them, weight and installation space are also saved in the battery 10 according to the invention.
[0035] In a further assembly step, as can be seen in the final illustration in Figure 8, the structure known from Figure 7 is then fixed with a structural encapsulation 7, analogous to the prior art, thereby securing it within the housing 2. The elastic, flexible sealing strip 12, which is again shown with the optional thermal barriers 13 in the illustration in Figure 8, prevents the structural encapsulation 7 from penetrating over a large area between the individual battery cells 4 and preventing them from moving during charging and discharging, known as breathing. Nevertheless, the structural encapsulation 7 can be used to fix the individual battery cells 4, which are already connected via the thermally conductive adhesive, in the housing 2, i.e. in particular to connect them to one another and to the housing walls 2.1.
Claims
Patent claims 1. Battery (10) with a housing (2) and at least one module of individual battery cells (4), which are inserted into the housing (2) as a composite (11), with at least one layer of a thermally conductive adhesive (8) and a structural encapsulation (7), characterized in that the composite (11) of the individual battery cells (4) has an elastic, flexible sealing band (12) between the stacked individual battery cells (4) in the stacking direction (S), by means of which the side surfaces of adjacent individual battery cells (4) are each held at a distance from one another.
2. Battery (10) according to claim 1, characterized in that the sealing strip (12) has a thermal barrier (13).
3. Battery (10) according to claim 1 or 2, characterized in that the composite (11) has at least one detachable alignment element (14) with spacers (15) projecting between the individual battery cells (4).
4. Battery (10) according to one of claims 1 to 3, characterized in that the composite (11) has at least one fixing aid (17).
5. Battery (10) according to claim 4, characterized in that the fixing aid (17) comprises at least one adhesive tape which is flexible in a height direction (H) has.
6. Battery (10) according to one of claims 4 or 5, characterized in that the fixing aid (17) has reinforcing fibers.
7. Battery (10) according to claim 4, 5 or 6, characterized in that the fixing aid (17) is designed to absorb forces in the stacking direction (S).
8. Battery (10) according to one of claims 1 to 7, characterized in that the structural encapsulation (7) comprises polyurethane.
9. A method for assembling a battery (10) according to one of claims 1 to 8, characterized in that the assembly (11) of individual battery cells (4) with an intermediate sealing tape (12) is stacked while maintaining a predetermined distance between the individual battery cells (4) in the stacking direction (S) and is fixed along the stacking direction (S), after which thermally conductive adhesive (8) is applied to a first inner surface of the housing (2), after which the assembly (11) is introduced into the housing (2) in such a way that its stacking direction extends parallel to the first inner surface, wherein the individual battery cells (4) are moved individually in the direction of the first inner surface or sink in this direction due to gravity, and after which the assembly (11) is fixed in the housing (2) by means of a structural casting (7).
10. Motor vehicle with a battery (10) according to one of claims 1 to 8, which has an at least partially electrically operated drive train which is connected to the battery (10) for power transmission.