This application claims priority to German Patent Application No. DE 10 2018 214 528.8, filed on Aug. 28, 2018, the contents of which are hereby incorporated by reference in its entirety.
The invention relates to an accumulator assembly for a hybrid or electric vehicle.
An accumulator assembly, or a traction battery, respectively, for a hybrid or electric vehicle usually has a plurality of individual battery cells which are combined so as to form a battery module. The individual battery cells in the respective battery module herein are held together by a tensioning device. In the case of pouch cells, the latter by virtue of their unstable shape have to be additionally held together by a suitable mounting or by suitable components, respectively. Furthermore, the individual battery cells in the battery module have to be cooled, wherein an improved heat dissipation between the individual battery cells bearing on one another is in particular pursued.
For example, in the case of pouch cells, auxiliary frames from plastics material can be utilized for establishing in a form-fitting manner and holding the individual battery cells in the respective battery module. For cooling the battery cells herein, ducts which can be passed through by a flow of coolant can be configured in the auxiliary frame. However, the auxiliary frame for establishing and for holding the individual battery cells is often used in the respective battery module, and cooling is performed by cooling structures which are thermally linked to the cell dissipators of the battery cells. Alternatively, U-shaped steel-sheet plates having an auxiliary frame from plastics material can be used for establishing in each case two battery cells on one another, wherein the respective battery cells established on one another are subsequently combined so as to form the respective battery module by way of tensioning brackets. The steel-sheet plates herein are utilized for dissipating heat from the battery cells to a coolant plate that is passed through by a flow of coolant.
In most instances, solutions of this type disadvantageously have an increased requirement in terms of space. Furthermore, the battery cells can often only be cooled from one cell side and, on account thereof, not be sufficiently cooled. Moreover, the equalization of tolerances and the sealing of the battery module can also be problematic.
It is therefore the object of the invention to specify an improved or at least alternative embodiment for accumulator assemblies of the generic type in which the disadvantages described are at least in part overcome.
Said object is achieved according to the invention by the subject matter of the independent claim(s). Advantageous embodiments are the subject matter of the dependent claim(s).
The present invention is based on the general concept of substituting complex construction element for holding and cooling in an accumulator assembly for a hybrid or electric vehicle with simple and multifunctional structural components. The accumulator assembly herein has a plurality of battery cells having mutually opposite bearing faces, wherein the battery cells in the stacking direction are stacked so as to face one another by way of the bearing faces and so as to form a battery block. The accumulator assembly furthermore has a cooling device having a plurality of cooling elements which are disposed between the neighbouring battery cells and conjointly with the latter are braced in the stacking direction. According to the invention, the respective cooling element has two at least in regions mutually spaced-apart compression plates which bear in a heat-transmitting manner on the bearing faces of the respective neighbouring battery cells and at least in regions delimit a compression space which is disposed between the compression plates and is compressible in the stacking direction. An expansion of the respective neighbouring battery cells in the stacking direction herein can be absorbed at least by the elastic deformation of the compression plates into the compression space.
In the accumulator assembly according to the invention, the heat generated in the battery cells can be dissipated through the respective cooling element. To this end, the compression plates can be formed from a heat-conducting material such as metal, for example. The cooling element herein by way of the compression plates bears in a planar and heat-transmitting manner on the bearing faces of the battery cells, and said cooling element can compensate the expansion, or an increase in thickness, respectively of the respective neighbouring battery cells. In the event of an expansion of the respective neighbouring battery cells, the compression plates can deform into the compression space such that the compression plates continue to bear in a planar and heat-transmitting manner on the bearing faces. The compression plates herein are elastically deformed such that the compression plates in the event of a contraction, or a decrease in thickness, respectively, of the respective neighbouring battery cells follow the respective bearing faces and continue to bear in a planar and heat-transmitting manner on said bearing faces. Consequently, on account of the cooling elements according to the invention, the individual battery cells can be effectively cooled independently of the variation in thickness of said battery cells as a result of the charge status or of aging. The compression space of the cooling element can be closed. For example, the compression plates can be fixed perpendicular to the stacking direction on each other at their opposite sides.
It can advantageously be provided that the respective cooling element is a metallic profile. The profile is preferably produced from aluminium and preferably by an extrusion press method or by an extrusion method, or is produced as a steel-sheet bent part. The metallic profile, in particular from aluminium, enables an effective dissipation of heat from the respective neighbouring battery cells. Moreover, the metallic profile can be produced in a time-saving and cost-saving manner by the extrusion press method or by the extrusion method such that the production costs and the production complexity can overall be reduced.
In one advantageous refinement of the solution according to the invention it is provided that the compression space at least in regions is filled with a compression element. The compression element herein can absorb the elastic deformation of the compression plates into the compression space. The compression element can advantageously be formed from a foam-type material or from a foam-type material composite. The foam-type material is preferably a polyurethane foam, and the foam-type material composite is preferably a polyurethane foam. The compression element herein can have a plurality of pores which can be passed through by a flow of a cooling fluid, for example. The pores of the compression element herein can be configured in such a manner that said pores can continue to be passed through by a flow of the cooling fluid even in the event of a compression of the compression element as a result of an expansion of the battery cells in the stacking direction. On account thereof, the compression plates in the compression space can be passed around by a flow of the cooling fluid and the dissipation of heat from the battery cells bearing on the compression plates can be intensified on account thereof. In order for a flow of the cooling fluid passing through the pores of the compression element to be optimized, the pores can be open, for example and be aligned in the flow direction of the cooling fluid. In order for the rigidity of the cooling element to be increased, the compression element can alternatively or additionally have at least one spring element that is disposed between the compression plates.
In one advantageous embodiment of the accumulator assembly the respective cooling element at least on one side can have a cell-holding collar. The cell-holding collar in the stacking direction can project from the respective compression plates at least on one side. In this instance, at least one of the respective neighbouring battery cells can at least in regions bear on the cell-holding collar and, on account thereof, can be established transversely to the stacking direction in the battery block. The cell-holding collar in the stacking direction can advantageously project from both sides and, on account thereof, can establish the two neighbouring battery cells transversely to the stacking direction. In this advantageous way the battery cells, and in particular pouch cells, in the battery block can be established transversely to the stacking direction by the respective cooling element such that a conventionally required mounting for the battery cells can be dispensed with and the overall construction of the accumulator assembly is simplified. The cell-holding collar in relation to the compression plates can at least in regions advantageously have an angle that deviates from 90° in order to reduce the risk of damage to the battery cells, and in particular to the pouch cells, when assembling. Alternatively or additionally, the cooling element at least on one side can have a peripheral support collar which in the stacking direction projects from both sides of the compression plates. The battery block can be supported in a housing by way of the support collar, for example.
It can advantageously be provided that the cell-holding collar and/or the support collar by way of a spring unit that is resilient transversely to the stacking direction are/is connected to the respective compression plates. A variation in the length of the cooling element transversely to the stacking direction herein can be compensated as a result of a deformation of the compression plates in the stacking direction. In particular, the battery cells herein are only insignificantly influenced by the cell-holding collar and, on account thereof, are additionally treated with care, independently of the variation in thickness of said battery cells in the stacking direction. The resilient spring unit can be formed, for example, by a corrugated connection region which adjoins the cell-holding collar and/or the support collar and/or at least one of the compression plates in an integral manner.
In the case of one advantageous refinement of the solution according to the invention it is provided that the cooling device has a cooling plate which can be passed through by a flow of a cooling fluid and is disposed on one side of the battery block. The respective cooling element in this instance can be established in a heat-transmitting manner, preferably a materially integral manner, at least on one side of the cooling plate. On account thereof, the heat generated in the battery cells by way of the compression plates of the cooling element can be dissipated to the cooling plate and at the latter be discharged to the cooling fluid. The cooling fluid can be a liquid. The compression plates and the cooling plate herein can be composed of a heat-conducting material, for example of metal and in particular of aluminium, so as to optimize the dissipation of heat from the battery cells to the cooling fluid. Alternatively, it can be provided that the cooling device has a fluid distributor and/or a fluid collector which can be passed through by a flow of cooling fluid and are/is in each case disposed on one side of the battery block. The respective cooling element herein can be passed through by a flow of a cooling fluid and is fluidically connected to the fluid distributor and/or to the fluid collector of the cooling device. The compression space of the cooling element can be closed such that a cooling fluid can flow through the compression space. The cooling fluid can be a liquid. In this advantageous way, the heat generated in the battery cells can be dissipated by way of the compression plates directly to the cooling fluid, and the dissipation of heat from the battery cells to the cooling fluid can be intensified.
Summarizing, the battery cells in the accumulator assembly according to the invention can be effectively cooled on both sides at the beginning as well as at the end of the life cycle independently of the variation in thickness of said battery cells by virtue of the charge status. Furthermore, the cooling element of the accumulator assembly according to the invention unifies thermal as well as mechanical functions and said cooling element can be embodied and produced in a simplified manner as a metallic profile. Additionally, the individual battery cells can also be established transversely to the stacking direction by the cooling element such that additional, conventionally required mountings are dispensed with. On account thereof, the overall construction of the battery block can advantageously be simplified.
Further important features and advantages of the invention are derived from the dependent claims, from the drawings, and from the associated description of the figures by means of the drawings.
It is understood that the features mentioned above and the features yet to be discussed below may be used not only in the respectively specified combination but also in other combinations or individually without departing from the scope of the present invention.
Preferred exemplary embodiments of the invention are illustrated in the drawings and will be explained in more detail in the description hereunder, wherein the same reference signs refer to identical or similar or functionally equivalent components.
In the schematic drawings:
An expansion, or an increase in thickness, respectively, of the respective neighbouring battery cells 2 in the stacking direction 5 in the accumulator assembly 1 can be absorbed by the elastic deformation of the compression plates 7a and 7b into the compression space 9. A contraction, or a decrease in thickness, respectively, of the respective neighbouring battery cells 2 can also be compensated by the compression plates 7a and 7b on account of the elastic deformation of the compression plates 7a and 7b. Consequently, the compression plates 7a and 7b in the event of a variation in thickness of the battery cells 2 bear on the bearing faces 8a and 8b and can effectively dissipate the heat generated in the battery cells. Summarizing, the individual battery cells 2 can be effectively cooled at the beginning as well as at the end of the life cycle independently of the variation in thickness of said battery cells by virtue of the charge status. The respective compression plates 7a and 7b are expediently composed of a heat-conducting material and can be of metal, for example, and in particular of aluminium.
The compression space 9 in this exemplary embodiment is completely filled with a compression element 10. The compression element 10 absorbs the elastic deformation of the compression plates 7a and 7b into the compression space 9, and said compression element 10 can be formed from a foam-type material, for example, or from a foam-type material composite. The foam-type material is preferably a polyurethane foam, and the foam-type material composite is preferably from a polyurethane foam. In order for the rigidity of the cooling element 4 to be increased, the compression element 10 can additionally have at least one spring element that is disposed between the two compression plates 7a and 7b. The compression element 10 can furthermore have a plurality of pores which can be passed through by a flow of a cooling fluid, for example. On account thereof, the compression plates 7a and 7b in the compression space 9 can be passed around by a flow of the cooling fluid and the dissipation of heat from the battery cells 2 bearing on the compression plates 7a and 7b can be intensified on account thereof.
The respective cooling element 4 moreover on both sides has a cell-holding collar 11 that projects on both sides. The cell-holding collar 11 herein in the stacking direction 5 projects from the compression plates 7a and 7b and establishes the respective neighbouring battery cells 2 transversely to the stacking direction 5. In this advantageous way, the battery cells 2, and in particular pouch cells, can be held in the battery block 6, and a conventionally required mounting for the battery cells 2 is dispensed with. The cell-holding collar 11 in this exemplary embodiment in relation to the compression plates 7a and 7b has an angle α equal to 90°. However, the angle α can also deviate from 90° in order to reduce a risk of damage to the battery cells 2, and in particular to the pouch cells, in the assembling. The cooling element 4 furthermore on both sides has a peripheral support collar 15 that projects on both sides in the stacking direction 5. The battery block 6 can be supported in a housing by way of the support collar 15, for example.
Summarizing, the battery cells 2 in the accumulator assembly 1 according to the invention are cooled on both sides. Furthermore, the dissipation of heat remains effective at the beginning as well as at the end of the life cycle of the battery cells 2, independently of the variation in thickness of the battery cells 2 by virtue of the charge status. Moreover, the cooling element 4 unifies thermal as well as mechanical functions and said cooling element 4 can be produced in a simplified manner as the metallic profile 12. A conventionally required mounting is advantageously also dispensed with since the individual battery cells 2 are established transversely to the stacking direction 5 by the cooling element 4. Overall, the overall construction of the battery block 6 and of the accumulator assembly 1 can advantageously be simplified.
Number | Date | Country | Kind |
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10 2018 214 528.8 | Aug 2018 | DE | national |