Patent Application
20200036062
This application claims priority to German Patent Application No. DE 10 2018 212 626.7, filed on Jul. 27, 2018, the contents of which are hereby incorporated by reference in its entirety
The invention relates to an accumulator arrangement for a hybrid or electric vehicle.
An accumulator arrangement or a traction battery, respectively, for a hybrid or electric vehicle typically comprises a plurality of individual battery cells, which are combined to form one battery module or also a plurality of battery modules. The individual battery cells are electrically interconnected in the respective battery module and supply the hybrid or electric vehicle with energy. In the case of the further development of the traction batteries, a short charging time is increasingly strived for, which leads to a high thermal load on the traction batteries. An effective temperature control of the individual battery cells is thus necessary in the traction battery.
For the respective battery module, a cooling device can thus for example be provided for this purpose, which cools the respective battery cells at the current collectors. The cooling device can thereby comprise a cooling plate, through which a coolant flows, to which the current collectors of the battery cells are fixed so as to transfer heat. Heat-conducting plates, which systematically dissipate the heat to the cooling plate, as is described, for example in DE 10 2008 061 755 A1, can additionally also be arranged between the battery cells. Such heat-conducting plates are disadvantageously fixed rigidly to the cooling plate, so that an expansion of the battery cells as a result of the charging state or of the aging of the battery cells can be partially prevented. Unwanted tensions can thereby be built up in the battery module. A solution for pouch cells is known from DE 10 2010 021 922 A1, in the case of which film elements, through which the cooling fluid can flow, are arranged between the pouch cells. The film elements are formed by two film layers, which are fixed to one another by means of a seam. The film elements abut against the pouch cells at a pressure, which is built up by the coolant. Other concepts, such as, for example, a housing comprising improved thermal properties, are further also known in DE 10 2013 206 581 A1.
It is the object of the invention to specify an improved or at least alternative embodiment for an accumulator arrangement of the generic type, in the case of which the described disadvantages are at least partially overcome.
This object is solved according to the invention by means of the subject matter of the independent claim(s). Advantageous embodiments are the subject matter of the dependent claim(s).
An accumulator arrangement is provided for a hybrid or electric vehicle and has a plurality of rigid battery cells comprising bearing surfaces located opposite one another, which facing one another with the bearing surfaces, are stacked to form a battery block in the stacking direction. The accumulator arrangement furthermore has a cooling device comprising a plurality of cooling elements, through which the cooling fluid can flow. The respective cooling element is thereby arranged between the adjacent battery cells and is clamped to the latter to form the battery block. The respective cooling element furthermore abuts against the bearing surfaces of the respective adjacent battery cells so as to transfer heat. According to the invention, the cooling device has a fluid distributor, which changes its shape in the stacking direction and through which the cooling fluid can fluid from a flow connection to a return connection via a fluid chamber, and which is fluidically connected to the respective cooling elements of the cooling device.
The flexible fluid distributor does not prevent a deformation of the battery block in the stacking direction, so that no unwanted tensions are built up in the battery block in response to the deformation of the battery cells as a result of the charging state or of the aging, and an excessive clamping of the battery block can be prevented in an advantageous manner. Unwanted tensions in the fluid distributor itself can furthermore be prevented in an advantageous manner, so that the tightness of the cooling device can be improved and the service life of the accumulator arrangement as a whole can be extended. The fluid distributor can advantageously consist of a fluid-tight and/or diffusion-tight material. The fluid-tight and/or diffusion-tight material is preferably plastic, such as polypropylene or polyethylene or polystyrene or, alternatively, a layered composite material, such as polypropylene-aluminum-polypropylene or polypropylene-aluminum-polyamide. A thickness of the material thereby lies between 0.1 mm and 0.6 mm.
It can advantageously be provided that, between the adjacent cooling elements, the fluid distributor in each case has a deformation area, which preferably deforms in response to a deformation of the fluid distributor in the stacking direction. When the battery block is not clamped, the fluid distributor is thereby not deformed in the deformation areas, and when the battery blocked is clamped, it is deformed in the deformation areas, so that the fluid distributor remains tension-free in the stacking direction in the case of the clamped battery block. The respective deformation areas thereby extend transversely to the stacking direction and along the battery cells, so that the respective cooling elements between the respective battery cells outside of the deformation areas can be fluidically connected to the fluid distributor. The deformation areas can be formed, for example, by areas comprising a smaller thickness of the material forming the fluid distributor. The deformation areas comprising the connection points of the respective cooling elements are thus arranged on the fluid distributor so as to alternate in the stacking direction.
The respective cooling element of the cooling device can advantageously have a fluid ingress and a fluid egress, which are arranged on a bottom side of the cooling element so as to be spaced apart from one another. The fluid ingress can furthermore be fluidically connected to a fluid inlet, and the fluid egress to a fluid outlet of the fluid distributor of the cooling device. An even supply of the cooling fluid to the respective fluid inlets and an even discharge of the cooling fluid from the respective fluid outlets is made possible thereby. At least one sealing contour or at least one sealing surface can in each case advantageously be embodied on the respective cooling element around the fluid ingress and around the fluid egress. The respective sealing contour or the respective sealing surface can then in each case seal the connection point between the fluid ingress and the fluid inlet or between the fluid egress and the fluid outlet to the outside.
It can advantageously be provided that an assembly distance, which is defined in the stacking direction, between the respective adjacent cooling elements is larger in the case of the non-deformed deformation areas, than a cell thickness of the respective battery cells, which is defined in the stacking direction. It can alternatively or additionally be provided that an element distance, which is defined in the stacking direction, between the respective adjacent fluid inlets and between the respective adjacent fluid outlets of the fluid distributor in the case of the non-clamped battery block is larger than in the case of the clamped battery block. In response to the clamping of the battery block, the fluid distributor changes its shape, and the element distance thus also changes in the stacking direction. The fluid distributor thereby preferably changes in the deformation areas, which are arranged between the respective cooling elements and which extend transversely to the stacking direction along the battery cells. The cooling elements are thereby fluidically connected to the fluid distributor outside of the respective adjacent deformation areas, so that the connection points between the fluid distributor and the respective cooling elements are not or only slightly influenced by the change of the shape of the fluid distributor in the deformation areas. The connection points between the fluid distributor and the respective cooling element can then be simplified and can thus be securely sealed due to the sealing contours at the fluid ingresses and at the fluid egresses of the respective cooling element.
In the case of an advantageous further development of the accumulator arrangement, it is provided that a plurality of flow channels for supplying the cooling fluid from the flow connection to the respective cooling elements and for discharging the cooling fluid from the respective cooling elements to the return connection are embodiment within the fluid chamber. The respective flow channels are thereby preferably arranged as a Tichelmann circuit in order to optimize a flow of the cooling fluid through the fluid chamber and the respective cooling elements.
It can advantageously be provided that the fluid distributor is a separate flat component for supplying cooling fluid to the respective cooling elements of the cooling device and for discharging cooling fluid from the respective cooling elements of the cooling device. The fluid chamber is thereby embodied completely inside the fluid distributor and is defined by the latter to the outside. The fluid distributor thus forms a conventional distributor or a conventional distributor pipe, respectively, as well as a conventional collector or a conventional manifold, respectively, in the accumulator arrangement. The fluid distributor is in particular a connected component, which is flat. In this context, “flat” means that the height of the fluid distributor compared to its width and its length is significantly smaller, or is smaller by a multiple, respectively. The fluid distributor can then abut on the battery block on one side and can be oriented parallel to the stacking direction.
The fluid distributor is preferably formed of an upper shell and a lower shell, which are fixed to one another in a fluid-tight manner—preferably by means of a substance-to-substance bond. The fluid chamber is then defined between the upper shell and the lower shell, and the cooling fluid can flow through it. The flow connection and the return connection can then be embodied in the upper shell as well as in the lower shell. If the fluid distributor has the flow channels, they can be formed, for example, by upper shell and lower shell of the fluid distributor, which are fixed to one another area by area and by means of a substance-to-substance bond in a linear manner. A connection structure, which defines a deformation of the fluid distributor, can furthermore be embodied on the upper shell and/or on the lower shell within the fluid chamber. In particular an unwanted inflating or an unwanted collapsing of the fluid distributor at a pressure, which is built up by the cooling fluid, can thus be prevented. The connection structure preferably has punctiform and/or oval-shaped and/or lens-shaped and/or linear connection areas, which are preferably oriented in the flow direction of the cooling fluid.
It can advantageously be provided that the respective cooling element has a frame, which revolves around the bearing surfaces of the respective adjacent battery cells on the edge side in the circumferential direction. An interior of the cooling element, through which the coolant can flow, is then arranged between the frame and the adjacent battery cells. The frame places the respective adjacent rigid battery cells—for example prismatic battery cells—at a distance to one another in an advantageous manner, so that the battery block has a length, which is predetermined in the stacking direction. The battery block can thus already be clamped with a predetermined clamping force in response to the assembly. The frame furthermore revolves around the bearing surfaces of the respective adjacent battery cells on the edge side in the circumferential direction, so that a deformation of the battery cells in an area, which is framed by the frame, of the bearing surfaces of the respective adjacent battery cells is thus not prevented. Independently of the deformation of the battery cells, the battery block thus remains clamped at the predetermined clamping force due to the charging state and the aging, and an excessive clamping of the battery block can be prevented in an advantageous manner. The cooling fluid can furthermore flow through the interior between the frame and the adjacent battery cells, so that the respective adjacent battery cells can be cooled efficiently by the cooling fluid. The service life of the battery cells as a whole can thus be significantly increased.
It can be provided in an advantageous manner that the frame is fixed to the bearing surfaces of the adjacent battery cells in a fluid-tight manner, so that the bearing surfaces of the adjacent battery cells define the interior of the cooling element, through which the fluid can flow, with the frame. The frame can thereby be connected to the respective adjacent battery cells by means of a substance-to-substance bond—for example adhered—or in a non-positive manner—for example clamped. The frame can consist, for example, of an electrically insulating material. The frame can thus be made of plastic, such as polypropylene, by means of injection molding. The cooling fluid can furthermore also be dielectric, in order to minimize the risk of a short-circuit in the battery block. The cooling device comprising the cooling elements embodied thereon is constructed in a simple manner, so that the production effort as a whole can be reduced. The cooling fluid can furthermore flow directly around the bearing surfaces of the respective adjacent battery cells, whereby the heat exchange between the bearing surfaces of the battery cells and the cooling fluid can be intensified, and the cooling of the battery cells can thus be improved.
It can alternatively be provided that flexible separating layers are fixed to the frame in a fluid-tight manner transversely to the stacking direction. The separating layers then define the interior of the cooling element, through which the fluid can flow with the frame. In the case of this embodiment of the cooling element, the separating layers can abut against the bearing surfaces of the respective adjacent battery cells at a pressure, which is built up by the cooling fluid, inside the interior, so that, independently of the deformation of the battery cells, the separating layers can abut against the bearing surfaces, and the heat exchange between the battery cells and the cooling fluid can take place in the interior of the cooling element. The frame and the respective separating layers can thereby consist of an electrically insulating material, so that the electrical properties of the respective battery cells adjacent to the cooling element are not influenced. In addition, the cooling fluid can be dielectric. The frame can consist, for example, of plastic, preferably of polypropylene, and can be produced by means of injection molding. The respective separating layer can be formed of plastic, preferably of polypropylene or polyethylene or polystyrene. Alternatively, the respective separating layer can consist of a layered composite material, preferably of polypropylene-aluminum-polypropylene or of polypropylene-aluminum-polyamide. A thickness of the respective separating layer in the stacking direction can thereby lie between 0.1 mm and 0.6 mm. Advantageously, the respective separating layer and the frame are diffusion-tight, so that the cooling element is fluid-tight to the outside.
In addition, it can advantageously be provided that at least one of the respective separating layers has a reinforcement structure, by means of which the deformation of the respective separating layer can be limited. In particular an unwanted inflating or an unwanted collapsing of the respective separating layers at a pressure, which is built up by the cooling fluid, can thus be prevented. The reinforcement structure thereby preferably has punctiform and/or oval-shaped and/or lens-shaped and/or linear embossings or neps or areas. The embossings or the neps or the areas of the reinforcement structure can thereby be oriented in the flow direction of the cooling fluid, in order to optimize the flow of the cooling fluid through the interior.
In the case of an advantageous further development of the accumulator arrangement according to the invention, it is provided that, on the respective frame at least on one side and at least area by area, a holding collar is embodied, which protrudes away from the frame in the stacking direction and which fixes the respective abutting battery cell transversely to the stacking direction at least area by area. The holding collar can thereby protrude on one side as well as on both sides in the stacking direction and can thus fix one of the battery cells as well as the two adjacent battery cells in the battery block transversely to the stacking direction. The holding collar can in particular support the weight of the respective battery cell during normal operation as well as in response to a strong acceleration—such as, for example, in the case of a crash. The cooling element thus advantageously fulfills thermal as well as mechanical functions, whereby the overall construction of the cooling device and thus the overall construction of the accumulator arrangement can be simplified.
It can advantageously be provided that the frame has a predetermined frame thickness in the stacking direction and that the respective adjacent battery cells are thus fixed in the clamped battery block at a predetermined cell distance identical to the frame thickness relative to one another. The frame thickness is preferably identical in the circumferential direction and lies between 0.5 mm and 5 mm. The cell distance of the respective adjacent battery cells thus preferably lies between 0.5 mm and 5 mm at least in the areas abutting against the frame. The cell distance of the respective adjacent battery cells corresponds to a distance of the bearing surfaces thereof, which face one another, in the stacking direction or to a width of the respective interior of the cooling element, respectively, which is formed between the bearing surfaces, which face one another, in the stacking direction. It goes without saying that the width of the interior as well as the distance of the bearing surfaces to one another can change during operation of the accumulator arrangement in an area of the bearing surfaces, which is framed by the frame, of the respective adjacent battery cells. The cell distance of the two adjacent battery cells, however, remains constant in the areas of the bearing surfaces, which abut against the frame, and corresponds to the frame thickness of the frame.
In the case of a further development of the battery block, it is provided that the battery block is clamped by at least one cell block tension rod, which extends in the stacking direction. The respective cooling element is then fixed to the at least one cell block tension rod in a positive manner by means of at least one form-fitting unit. In this advantageous manner, the individual cooling elements and thus also the battery cells arranged between the respective cooling elements can be fixed to the at least one cell block tension rod. The at least one cell block tension rod can in particular support the weight of the respective battery cells and of the respective cooling elements during normal operation as well as in response to a strong acceleration—such as, for example, in the case of a crash. The at least one cell block tension rod can be arranged below the battery block for this purpose, wherein “below” refers to the accumulator arrangement, which is installed into the hybrid or electric vehicle. It can alternatively or additionally be provided that the battery block is clamped by at least one cell block tie anchor, which extends in the stacking direction, and that the at least one cell block tension rod has a plurality of mounting brackets protruding transversely to the stacking direction on both sides for fixing the accumulator arrangement to the hybrid or electric vehicle. The at least one cell block tension rod is then preferably arranged with the mounting brackets below the battery block, in order to be able to support the weight of the battery block.
Independently of the embodiment of the at least one cell block tension rod, the battery block is preferably arranged between at least two cell block tension rods, which are oriented in the stacking direction and which abut against the battery block on opposite sides thereof. The cell block tension rods can thereby be embodied differently. In addition, the battery block can be arranged between two clamping plates, which, on opposite sides of the battery block, abut against the latter transversely to the stacking direction. The respective clamping plates and thus also the battery block arranged between the clamping plates can then be clamped to one another in the stacking direction by means of the respective cell block tension rods. The battery block can thereby in particular be clamped evenly and the created clamping force can be introduced evenly into the battery block. The cell block tension rods and/or the clamping plates can consist, for example, of steel or of aluminum or of fiber-reinforced plastic.
It is provided in the case of an advantageous further development of the accumulator arrangement that the respective cooling elements are arranged in the battery block so as to alternate with the respective battery cells in the stacking direction. The respective cooling element thereby in each case follows one of the respective battery cells or in each case two of the battery cells abutting against one another. If the respective cooling element in each case follows one of the respective battery cells, the respective battery cells in the battery block can be cooled on the two bearing surfaces and thus optimally. If the respective cooling element in each case follows two of the battery cells, which abut against one another, the number of the cooling elements in the battery block and thus the weight of the battery block can be reduced.
The accumulator arrangement can advantageously have a housing comprising a top part and comprising a bottom part, which are fixed to one another in a fluid-tight manner and which form a fluid-tight receiving space for the battery block. The top part and the bottom part can thus be fixed to one another by means of a substance-to-substance bond—by means of a welding connection or by means of an adhesive connection. The top part and/or the bottom part can consist of a fluid-tight and/or diffusion-tight and/or thermally insulating material. The material can be plastic, such as polypropylene or polyamide or can alternatively be a layered composite material, such as a polypropylene-aluminum composite material or a polypropylene-steel composite material. A thickness of the top part and/or of the bottom part can thereby lie between 1 mm and 3.5 mm, whereby the top part and/or the bottom part are particularly light and the weight of the accumulator arrangement can be reduced in an advantageous manner.
In summary, the fluid distributor is fixed in the accumulator arrangement in a tension-free manner and does not prevent a deformation of the battery cells in the stacking direction as a result of the charging state or of the aging. In addition, the battery cells can be cooled effectively and on both sides. In the accumulator arrangement according to the invention, the cooling elements furthermore combine thermal as well as mechanical functions, whereby the number of the individual parts in the accumulator arrangement can be reduced and the overall construction of the accumulator arrangement can be simplified.
Further important features and advantages of the invention follow from the subclaims, from the drawings, and from the corresponding figure description on the basis of the drawings.
It goes without saying that the above-mentioned features and the features, which will be described below, cannot only be used in the respective specified combination, but also in other combinations or alone, without leaving the scope of the present invention.
Preferred exemplary embodiments of the invention are illustrated in the drawings and will be described in more detail in the following description, wherein identical reference numerals refer to identical or similar or functionally identical components.
The respective cooling element 7 thereby as frame 12, which revolves around the bearing surfaces 3 of the respective adjacent battery cells 2 on the edge side in the circumferential direction 13. Flexible separating layers 14, which define an interior 15 of the cooling element 7 with the frame 12, are fixed to the frame 12 in a fluid-tight manner transversely to the stacking direction 4. The interior 15 of the respective cooling element 7 is advantageously connected to the fluid chamber 11 of the fluid distributor 8 and the cooling fluid can flow through it. On opposite sides 16 and on a bottom side 17 of the cooling element 7, a holding collar 18 is in each case formed, which protrudes away from the cooling element 7 on both sides in the stacking direction 4—as can in particular be seen in
As shown in
In the accumulator arrangement 1 according to the invention, the cooling element 7 places the respective adjacent rigid battery cells 2 at a distance to one another in an advantageous manner and does not prevent a deformation of the battery cells 2 as a result of the charging state or the aging. Independently of the deformation of the battery cells 2, the battery block 5 thus remains clamped at the predetermined clamping force and an excessive clamping of the battery block 5 can be prevented in an advantageous manner. The advantageous effect of the cooling element 7 in the accumulator arrangement 1 according to the invention will be described in more detail below on the basis of
According to
In
The accumulator arrangement 1 is now shown during operation in
In summary, the deformation of the battery cells 2 in the accumulator arrangement 1 according to the invention is not limited as a result of the charging state or of the aging, and an excessive clamping of the battery block 5 in the stacking direction 4 can be prevented. The fluid distributor 8 furthermore remains free from tension and the risk of a leakage can thus be minimized. The battery cells 2 can furthermore be cooled effectively and on both sides, so that the service life of the battery cells 2 as a whole can be extended in an advantageous manner. The cooling elements 7 further combine thermal and mechanical functions, so that the overall construction of the accumulator arrangement 1 can be simplified.
| Number | Date | Country | Kind |
|---|---|---|---|
| 102018212626.7 | Jul 2018 | DE | national |
