Compression pad for the spaced-apart arrangement of battery cells in a battery pack, battery cell, battery pack, and vehicle having a battery pack

Abstract

The invention relates to a compression pad 1 for the spaced-apart arrangement of battery cells in a battery pack, comprising a first planar spacer layer 2 and a second planar spacer layer 3, wherein the spacer layers 2, 3 each have a first side face 5 and a second side face 6, wherein the second spacer layer 3 is arranged on the first spacer layer 2. The invention is distinguished in that both the first spacer layer 2 and the second spacer layer 3 have at least one cutout 7, each of which extends from the first side face 5 to the second side face 6, and wherein the first spacer layer 2 is arranged on the second spacer layer 3 and / or the cutouts 7 are arranged on the spacer layers 2, 3 in such a way that the cutouts 7 in the first and in the second spacer layer 2, 3 partially overlap, so that in each case at least one of the cutouts 7 in the first spacer layer 2 and at least one of the cutouts 7 in the second spacer layer 3 form at least one continuous flow duct 4 through the compression pad 1 for the purpose of transporting fluid.

Description

[0001] Compression pad for the spaced arrangement of battery cells in a battery pack, battery cell, battery pack and vehicle with battery pack

[0002] The invention relates to a compression pad for the spaced arrangement of battery cells in a battery pack. The present invention further relates to a battery cell, a battery pack, and a vehicle, each comprising a compression pad according to the invention.

[0003] In the field of automotive technology, battery packs consisting of numerous individual battery cells are increasingly being used. The individual battery cells are usually assembled into a battery pack in a housing. It is important that the battery cells are securely positioned within the housing.

[0004] In this technical field, the term battery is used synonymously with the term accumulator or battery, so that a battery is also understood to mean a rechargeable accumulator.

[0005] During use, battery cells are subject to temperature fluctuations, which lead to thermal expansion. Depending on the battery type used, battery cells also tend to "breathe" during charging and discharging, meaning they expand and contract again, or they may expand or fail to return to their original shape due to aging processes and / or improper handling. This expansion behavior is particularly pronounced in lithium-based batteries.

[0006] A certain degree of mechanical compression of the battery cells can support the battery cells during this expansion and contraction, thus increasing their efficiency and improving their performance or capacity towards the end of their life cycle. This can extend the service life of the battery cells. Therefore, compression pads are used in the battery packs in the prior art. These pads are arranged between the battery cells and between the battery cells and the housing. These compression pads have a certain compressive stiffness, or in other words, a certain degree of flexibility, which allows the battery cells to be pre-tensioned against each other and against the housing with a certain compressive stress, thus supporting the battery cells in particular during expansion and contraction.The flexibility of the compression pads, unlike a rigid arrangement, allows the battery cells to expand—particularly against the elastic force of the compression pads—and contract again—particularly supported by the elastic force of the compression pads. The occurrence of excessive compressive stresses between the battery cells or the housing can also be avoided.

[0007] To improve the service life and / or performance of the battery cells, they are often cooled. This can be achieved using heat sinks, which are usually located at the ends of the battery cells and connected to the battery cells using thermal paste, for example. A battery pack casing can also serve as a heat sink.

[0008] However, there are also solutions where the battery cells are cooled by a fluid flow. For this, a water- or oil-based coolant is used, for example. The coolant must be directed past the surfaces of the battery cells. The top ends of the battery cells, where the coolant is directed, are ideal for this purpose. The top ends of the battery cells are ideal because they are usually easily accessible in a battery pack. Analogous to a liquid, a gas such as air can also be used as a fluid flow for cooling.

[0009] The sides of the battery cells are also suitable for cooling in principle, but are generally not easily accessible because the battery cells are arranged close together via compression pads on the sides. A compression pad between the battery cells therefore generally impairs the flow of coolant, as the compression pad, depending on its design, acts as a liquid-tight separating layer or at least has such a high flow resistance that the compression pad cannot be effectively penetrated by a coolant flow.

[0010] The present invention is therefore based on the object of providing an improved compression pad which promotes or even enables the cooling of the battery cells by a fluid flow.

[0011] This object is achieved by the subject matter of the independent patent claims. Preferred embodiments of the present invention emerge from the features recited in the subclaims and further from the present disclosure as a whole.

[0012] A first aspect of the invention relates to a compression pad for the spaced arrangement of battery cells in a battery pack, comprising a first and a second planar spacer layer, each having a length, a width, and a thickness, wherein the length and the width are each a multiple of the thickness. The spacer layers each have a first side surface and a second side surface, which are each spanned by the length and the width of the spacer layer. The second spacer layer is arranged on the first spacer layer in the compression pad such that a side surface of the first spacer layer and a side surface of the second spacer layer coincide and form a contact surface between the two spacer layers.

[0013] The invention is characterized in that both the first spacer layer and the second spacer layer have at least one recess, which each extend through the spacer layer from its first side surface to its second side surface. The first spacer layer is arranged on the second spacer layer and / or the recesses are arranged on the spacer layers in such a way that the recesses of the first and second spacer layers partially overlap, so that at least one of the recesses in the first spacer layer and at least one of the recesses in the second spacer layer jointly form at least one continuous flow channel through the compression pad for fluid transport. Both the compression pad itself and the spacer layers are flat. Flat in the sense of the application means that the pads orLayers have a rectangular shape whose length and width are many times greater than their thickness. Typically, the width is 20 to 150 mm, and the length 50 to 500 mm. The thickness of the entire compression pad can be 0.1 to 5 mm. In particular, the width is 80 to 120 mm, the length 200 to 300 mm, and the thickness 1 to 6 mm. A thickness of 2 to 3 mm for the entire compression pad has proven particularly preferred. The length and width can be adapted to existing battery cells. For example, a width of the compression pad can correspond to the height of a cylindrical battery cell, or the width or length of a cuboid battery cell, or a multiple thereof. With regard to existing battery cells, a length of 517 mm or 550 mm and a width of 101 mm have therefore proven particularly preferred. The thickness of the spacer layer alone can be 0.5 to 2.5 mm, especially 1.2 mm.

[0014] The flow channel essentially runs in the area of ​​the compression pad.

[0015] An additional adhesive layer can be arranged between the two spacer layers. Likewise, additional adhesive layers can be arranged on the side surfaces of the spacer layers facing away from the contact surface, for example, to attach additional functional layers or to attach the compression pad to the battery cells. A dispersion-based polyacrylate (polyacrylic acid ester), for example, can be used as the adhesive layer.

[0016] The spacer layers each have at least one recess which runs from one side surface to the other side surface of a spacer layer. One possibility for producing the recesses in the spacer layers is to introduce them, for example by punching or lasering recesses into the spacer layers, so that through holes are created in the flat spacer layer. However, other manufacturing processes such as water jet cutting, milling or the like can also be used to produce the recesses. They can also be formed directly in a foaming tool used to produce the spacer layers. The recesses preferably extend in an orthogonal direction from the first side surface to the second side surface, but it can also be advantageous if the recesses run obliquely (skewed), i.e. not orthogonally, from one side surface to the other.

[0017] The recesses are arranged in the two spacer layers in such a way that they partially overlap when the spacer layers are joined to form a compression pad, thus forming a continuous flow channel through which the fluid can flow through the compression pad. Such an arrangement of two spacer layers with their respective overlapping recesses offers the advantage, particularly compared to a compression pad with only a single spacer layer, that flow channels can be formed very easily and cost-effectively within the compression pad. These flow channels can be incorporated into the spacer layers using simple and therefore generally cost-effective manufacturing processes (as described above).

[0018] If only one recess is provided per spacer layer, the fluid first flows in the compression pad through the recess of the first spacer layer, then flows through the contact surface between the spacer layers into the recess of the second spacer layer, and from there out of the compression pad again.

[0019] If multiple cutouts are provided per spacer layer, the fluid flows alternately first through a cutout in the first spacer layer and then through a cutout in the second spacer layer. The flow channel is then formed in the direction of fluid flow through the flow channel by alternating cutouts in the first and second spacer layers. In each case, one end of one cutout overlaps with the beginning of the other cutout, whereby in the first and last cutouts in the flow channel, the beginning of the first cutout and the end of the last cutout do not overlap with any other cutout.

[0020] Preferably, a cross-sectional area of ​​the flow channel or the respective flow channels, which is spanned perpendicular to the flow direction in the flow channel, is at least 2 mm along the entire length of the flow channel 2 , at least 4 mm 2 , or at least 6 mm2 This avoids increased flow resistance due to constrictions in the flow channel, i.e., local cross-sectional areas smaller than those specified in this paragraph. Such disadvantageous constrictions typically occur in flow channels formed through open-pore foams.

[0021] The flow channel or recesses are open on the side surfaces towards the battery cells so that the fluid can come into direct contact with the battery cells.

[0022] However, it can also be provided that further layers, such as a sealing layer or a flame-retardant protective layer, are arranged on the outer side surfaces of the spacer layers, which closes off the flow channels in the direction of the battery cells so that the fluid does not come into direct contact with the battery cells.

[0023] The spacer layers can be compressible or essentially incompressible. In other words, the spacer layers can be designed as a solid body with high compressive stiffness, or, for example, as a foam with lower compressive stiffness compared to the solid body.

[0024] A combination of a spacer layer with high compressive stiffness and a spacer layer with low compressive stiffness can be advantageous. However, a combination of spacer layers with comparable high or low compressive stiffness can also be advantageous.

[0025] To form the flow channels, the recesses can be arranged in regular patterns, wherein the pattern of the recesses of the first spacer layer is offset from the pattern of the recesses of the second spacer layer in such a way that the recesses partially and preferably mutually overlap and thus form the at least one flow channel.

[0026] Such a regular pattern can be, for example, a checkerboard pattern, or a specific shape of a recess that preferably repeats regularly in the direction of the length and / or in the direction of the width of the spacer layer.

[0027] In one embodiment of the compression pad, at least one of the spacer layers is formed as an elastic compression layer that is configured to support expansion and contraction of the battery cells.

[0028] It is conceivable that one of the spacer layers is essentially incompressible, or at least has a much higher compressive stiffness than the other spacer layer, which serves as a compression layer.

[0029] It is generally advantageous if both spacer layers serve as compression layers, so that preferably both spacer layers are each designed as an elastic compression layer.

[0030] Such elastic compression layers are preferably formed from a foam, more preferably from a PE foam, in particular from a cross-linked PE foam. However, it is also conceivable that a nonwoven or a fiber material is used as the compression layer.

[0031] PO (polyolefin) and especially PE (polyethylene) is a cost-effective plastic that is conditionally heat-resistant, for example up to 100°C depending on the design, and is therefore suitable for use in battery packs. Battery packs rarely reach temperatures above 100°C during operation, as higher temperatures severely limit the service life of the battery packs. The PO or PE can be in the form of foam, with the compressive stiffness of such a foam layer being within a usable range for battery pack production. Optional protective layers additionally applied to the compression layer can provide limited protection for the PO or PE from the heat of the batteries. The number and size of the foam pores can be individually adjusted during production of the compression layer, allowing the compressive stiffness to be influenced.

[0032] Cross-linked PE is particularly suitable as a material for the compression layer, so that in one embodiment, the compression layer is made of cross-linked PE foam. In the context of this invention, this refers in particular to chemically or physically cross-linked PE foam, in which the polymer chains are chemically or physically bonded to one another at specific points to form a three-dimensional network. Cross-linked PE is also referred to as PEX. The mechanical and thermal properties of cross-linked PE are generally better than those of regular PE. Compared to thermoplastic, i.e., the aforementioned regular PE, cross-linked PE does not melt and is more thermally stable.

[0033] Alternatively or in addition to PE foam, the compression layer can be made of, for example, PUR foam (polyurethane foam), PO foam (polyolefin foam), or melamine resin foam. Silicone foams can also be advantageous. The compression layer can preferably be made of or consist of one or more of the aforementioned foams.

[0034] A compression layer made of or consisting of cross-linked PO foam is preferred (analogous to the previously described cross-linked PE foam).

[0035] Compressed PUR foam can also be used as a material for the compression layer. Compressed PUR foam can be either fully compressed PUR foam that has been mechanically compressed, or it can be a PUR foam whose surface has been compressed. The surface can be compressed either mechanically or thermally. If the compression layer is made of PUR foam, at least one of the surfaces of the compression layer can be compressed, for example, at least those surfaces of the compression layer that have direct or indirect contact with the battery cells. Compressing the PUR foam has a positive effect on the material's mechanical properties. Compressing the foam can also influence the pore structure of the foam. Therefore, the compression layer is preferably made of a compressed PUR foam or consists entirely of it.

[0036] A compression layer made of or consisting of high-temperature foam, such as melamine resin foam, can also be advantageous. The compressive stiffness of a suitable compression layer, particularly made of PE foam, PO foam, PUR foam, melamine resin foam, or silicone foam, as well as their cross-linked or compacted form, can be in the range of 150 to 200 kPa, particularly 160 to 180 kPa, at a compression of 50%.

[0037] The compression layer is preferably designed such that at the beginning of the battery pack's service life, i.e. when the battery cells are installed in the housing, the compression layer is compressed to approximately 70% of its thickness in the unloaded state in order to achieve the necessary prestress for mechanically fixing the battery cells. Towards the end of the battery pack's service life, the compression layer can then be compressed to approximately 30% of its unloaded thickness due to the expansion of the battery cells. In particular, a compression curve of the compression layer is linear between a compression of 70% and 30%. The compression in percent here refers to a thickness of the compression layer in the installed, i.e. loaded, state relative to a thickness of the compression layer in an unloaded state. The compression curve relates this percentage compression to the compressive stress acting on the compression layer.

[0038] When the compression layer is compressed to 30% of its unloaded thickness, or at a comparable compression of this magnitude, the compression layer may be compressed to a solid block (to a block dimension). The compression layer should preferably still be capable of conducting a fluid through the compression layer. Therefore, the compression layer is preferably designed such that the compression layer allows coolant flow through the compression layer when compressed to 30% of its unloaded thickness and / or when compressed to its block dimension. In other words, in this state, the compression layer continues to have continuous pores for fluid conduction through the compression pad.

[0039] If the compression layer is not capable of this, spacers can be provided to limit compression of the compression layer such that the compression layer continues to allow coolant flow even at maximum compression. Such a maximum compression limited by spacers can, for example, be a compression of 30%. In a further embodiment, the compression layer comprises or consists of a non-foamed material. The non-foamed material can, for example, be an elastomer rubber. Elastomer rubber is made of natural rubber and / or synthetic rubber.

[0040] In one embodiment of the compression pad, the spacer layers each have a plurality of recesses, wherein the plurality of recesses of the first spacer layer and the plurality of recesses of the second spacer layer are arranged such that a recess of the first spacer layer and a recess of the second spacer layer alternately form a part of the flow channel along a flow direction through the flow channel.

[0041] The flow direction corresponds to the direction in which the fluid flows along the flow channel. The flow direction can change spatial direction several times, following the course of the flow channel.

[0042] The recesses forming a flow channel are arranged "alternately to the contact surface" along the flow direction of the fluid through the flow channel, so that the fluid flows meanderingly through the flow channel and, when flowing from one recess to the next, flows from one side of the contact surface to the other side of the contact surface.

[0043] In this arrangement, except for the first and last recess, one end of one recess overlaps the beginning of the next recess.

[0044] In one embodiment of the compression pad, the at least one flow channel runs from a first longitudinal side of the compression pad to an opposite second longitudinal side of the compression pad, and / or from a first broad side of the compression pad to an opposite second broad side of the compression pad, such that fluid can be transported from the first longitudinal side to the opposite second longitudinal side and / or from the first broad side to the opposite second broad side. The flow channel does not have to run in a straight line or on a direct path between the respective sides, but can meander as desired between the sides or follow other courses. In particular, it can also be provided that the flow channel runs from one longitudinal side to one broad side.

[0045] The fluid transport can also take place diagonally; for this purpose, the at least one flow channel can run diagonally from a first corner of the compression pad to a diagonally opposite second corner of the compression pad.

[0046] Preferably, several channels run parallel from one long side to the other long side and / or from one wide side to the other wide side and / or from one long side to a wide side.

[0047] The long sides are the sides of the compression pad, which are spanned by the length of the spacer layer and the two thicknesses of the spacer layers. The wide sides are the sides of the compression pad, which are spanned by the width of the spacer layer and the two thicknesses of the spacer layers.

[0048] In one embodiment of the compression pad, the compression pad has a plurality of flow channels arranged in the compression pad in such a way that the individual flow channels are fluidically connected to one another via the recesses. For this purpose, for example, several flow channels can be connected to one another via a specific recess, which can, for example, improve the flow resistance or the volume flows in the flow channels.

[0049] For the purposes of the application, "fluidically connected" means that the fluidic connection is realized, for example, via overlapping recesses. This does not include, for example, the microscopic connections between the flow channels, which can be present, for example, by using at least one spacer layer made of a porous material, such as a foam with continuous pores, or a fiber material.

[0050] In one embodiment of the compression pad, the compression pad has multiple flow channels, wherein the flow channels are evenly distributed across the contact surface in the compression pad. In particular, the flow channels may not be evenly arranged in an inlet and outlet area of ​​the flow channels. The even arrangement of multiple flow channels distributed across the contact surface or evenly distributed across the compression pad achieves a uniform flow through the compression pad, thus also achieving a uniform cooling effect of the fluid. For this purpose, multiple flow channels can be arranged parallel to one another.

[0051] In particular, the at least one or more flow channels run in a meandering manner through the compression pad.

[0052] In one embodiment of the compression pad, the compression pad has a plurality of flow channels, wherein the flow channels are interconnected by recesses. The flow channels and recesses are arranged such that a permeable mesh structure is formed over at least part of the contact surface. It can be advantageous if the flow channels form a type of mesh structure in order to ensure that fluid flows through the compression pad as evenly as possible. Heat dissipation can also be improved by the mesh structure.

[0053] To form the network structure, the flow channels can be connected at certain intervals by additional recesses.

[0054] The mesh structure can also be achieved without additional recesses. Therefore, in one embodiment, the compression pad has multiple flow channels, wherein the flow channels are arranged so as to cross one another, so that a permeable mesh structure is formed over at least part of the contact surface. In this case, the mesh structure can be formed by certain recesses serving as part of multiple flow channels. At the intersection points of the flow channels, the flow channels then share a specific recess and are thus fluidically connected to one another.

[0055] However, it can also be advantageous if the flow channels are not fluidically connected to one another. Therefore, in one embodiment of the compression pad, the compression pad has multiple flow channels arranged within the compression pad in such a way that the individual flow channels are fluidically separated from one another. The flow through individual, defined flow channels can often be better controlled and regulated, so that unconnected flow channels can be advantageous.

[0056] For the purposes of the application, the flow channels are fluidically separated from one another even if the flow channels are connected only by microscopic connections between the flow channels, which can be provided, for example, by using at least one spacer layer made of a porous material, such as a foam with continuous pores or a fiber material. For example, with such fluidic separation, the recesses of different flow channels do not overlap.

[0057] In one embodiment of the compression pad, the compression pad has at least one flame-retardant and / or thermally insulating protective layer, which is arranged on a side surface of the spacer layers facing away from the contact surface. In other words, the protective layer is arranged on one of the outer side surfaces of the spacer layers.

[0058] In particular, the compression pad has two protective layers which are arranged on the two side surfaces of the spacer layers facing away from the contact surface.

[0059] Flame-retardant materials are those that may burn when exposed to heat, but do not continue to burn independently when the heat is removed. A suitable flame-retardant protective layer, for example, is one made of mica or at least containing a significant amount of mica.

[0060] Mica, also known as mica or the mica group, comprises a group of minerals consisting of layered silicates. The protective layer can consist essentially of mica, whereby the protective layer can comprise a matrix or matrix material for mechanical stabilization of the mica. The mica can be arranged on a mat, particularly a mesh mat.

[0061] The protective layer can protect both the spacer layer and the battery cells from heat and flames, as well as from each other. For example, if a defective battery cell catches fire, the protective layer can prevent the flames emanating from that battery cell from spreading to other battery cells.

[0062] Preferably, one or two protective layers are made of a mineral-based material. Mineral-based materials have an inorganic base and are in contrast to organic-based materials. Mineral-based materials have a mineral, non-metallic component such as lime, cement, gypsum, or silicate. Natural minerals such as sand, natural stone, or clay can also be considered as such a component, as can any combination of the substances mentioned in this paragraph. For example, a protective layer made of mica is made of a mineral base. The protective layers can also consist exclusively of one of the components mentioned in this paragraph or a combination of these components.

[0063] Preferably, only the spacer layers are provided with recesses, so that the protective layers retain their continuous surface and, for example, a higher flame-retardant effect is maintained. However, it can be advantageous if the protective layers are also provided with recesses, so that, for example, the fluid can come into direct contact with the battery cells.

[0064] In one embodiment of the compression pad, at least one spacer layer has a plurality of macroscopic regions extending on the first and / or second side surface with different compressive stiffnesses. Preferably, the compressive stiffnesses are measured in a direction orthogonal to the first and / or second side surface. The at least one spacer layer has, in particular, a different number of cutouts and / or cutouts of different sizes in the different regions to create the regions with different compressive stiffnesses. The size of the cutout refers to a cross-sectional area of ​​the cutouts, viewed in a plane parallel to one of the side surfaces of the spacer layer.

[0065] The spacer layer has regions with varying compressive stiffnesses. These regions have macroscopic dimensions. In the application, "macroscopic" means that the regions are several millimeters in size and can range up to several centimeters or several decimeters. This does not include microscopic regions of a few millimeters or tenths of a millimeter in size or less. This is intended to disregard fluctuations in compressive stiffness resulting from individual pores or fiber gaps in the spacer layer material, as these do not reflect the compressive stiffness of the material itself.

[0066] The aim of this embodiment is to set the compressive stiffness of the compression layer lower where the battery cells expand the most over their service life due to aging processes or the like. Cuboid or prismatic cells bulge out in a pillow-like manner at their surfaces, so that the expansion of the battery cell is greatest in the center of the surfaces of the cuboid or prism and decreases towards the edges. In cylindrical battery cells, the expansion is greatest halfway up the cylinder and decreases towards the circular end surfaces. Therefore, the compressive stiffness of the spacer layer should be set lower in the contact area halfway up the cylinder than towards the ends of the cylinder. The same applies accordingly to cuboid or prismatic battery cells.

[0067] As a rule, the region of the spacer layer that has a lower compressive stiffness corresponds to the region around a centerline that arises between the two long sides of the spacer layer. This region is referred to as the central region. Particularly for use of the compression pad in cuboid or prismatic battery cells, the central region can extend along a centerline that is arranged between the two edges that extend in the width of the compression pad. In this way, a central region is created in the middle of the first and / or second side surface of the spacer layer. The regions with higher compressive stiffness extend along the long sides of the spacer layer and extend from there towards the centerline. These regions are referred to as edge regions.In addition, further regions can be provided that lie between the regions with the highest and lowest compressive stiffness, and whose compressive stiffness lies between the highest and lowest compressive stiffness. These regions are referred to as intermediate regions. Preferably, the central region borders the intermediate regions, and the intermediate regions border the edge regions, with neither the central region and intermediate regions nor the edge regions and intermediate regions overlapping.

[0068] The recesses are therefore arranged such that in a central region of the spacer layer the number of recesses and / or the total cross-sectional area of ​​the recesses is greater than in the edge regions. The central region extends along a center line between two long sides of the compression layer and, in particular, additionally extends in the direction of the long sides. The edge regions border the long sides and extend along the long sides, with the edge regions extending, in particular, starting from the long sides in the direction of the center line. The central region and the edge region can border one another or border other regions, such as the intermediate region. However, the individual regions do not overlap.

[0069] The extension of the central region can be formed symmetrically in both directions from the center line towards the long sides of the spacer layer, so that the recesses are then also arranged symmetrically to the center line.

[0070] Compressive stiffness can be influenced by the number of cutouts. The more cutouts are incorporated into the spacer layer relative to a given area, the lower the compressive stiffness in that area, since the compressive stiffness is considered averaged over the entire area.

[0071] Preferably, the protective layers contribute to averaging the compressive stiffness of the compression pad as a whole. This depends on the total cross-sectional area of ​​the recesses relative to a specific area. The larger the total cross-sectional area of ​​the recesses, i.e., the negative area relative to a specific area, the lower the compressive stiffness. Therefore, in addition to the number of recesses, the size of the cross-sectional area of ​​the recesses can also be varied to adjust the compressive stiffness of the spacer layer in the individual areas.

[0072] The invention also relates to a compression pad for the spaced arrangement of battery cells in a battery pack, comprising a flat spacer layer with a length, a width, and a thickness, wherein the length and the width are a multiple of the thickness, wherein the spacer layer has a first side surface and a second side surface, which are each spanned by the length and the width. It is characterized in that at least one continuous flow channel for fluid transport through the compression pad is formed through the spacer layer.

[0073] In one embodiment of the compression pad, the spacer layer is formed from a porous material and / or a fiber material, through which a plurality of continuous and optionally interconnected flow channels are provided for fluid transport through the compression pad.

[0074] The previously mentioned foams, reticulated foams (filter foams), or fiber materials can be used as porous materials for the spacer layer. Therefore, the spacer layer preferably comprises these materials, or more preferably consists of them.

[0075] In one embodiment of the compression pad, channels are incorporated into the spacer layer, serving as flow channels. These channels are formed by depressions or grooves on the first and / or second side surfaces. The depressions can be created by deforming a surface of the side surfaces or, for example, by a milling process.

[0076] The flow channels can be straight or meandering. Several flow channels can be arranged in parallel. Distributing the flow channels or having a single flow channel run evenly across the side surface of the spacer layer can also be advantageous. In addition to individual, unconnected flow channels, several flow channels can also be connected to form a network structure. For example, if the flow channels are arranged in a crisscrossing manner.

[0077] In contrast to the recesses explained so far, the flow channels of this embodiment do not run from the first side surface to the second side surface, but run only on one of the two side surfaces of the spacer surface.

[0078] The invention further comprises a battery cell with a compression pad according to the invention, wherein the compression pad is arranged on an outer surface of the battery cell and is configured for the spaced arrangement of the battery cell from another battery cell in a battery pack. The compression pad can be arranged on a rectangular ("pouch-shaped") battery cell, as well as on a prismatic battery cell, or on a cylindrical battery cell. In a cylindrical battery cell, the compression pad is arranged on the outer surface of the cylinder and can cover only part of the outer surface.

[0079] The compression pad may protrude beyond the outer surface on which the compression pad is arranged, for example to enable or facilitate a fluidic connection of the flow channels.

[0080] The compression pad can be connected to the outer surface of the battery cell, for example via an adhesive layer, so that the compression pad is securely positioned on the battery cell.

[0081] Battery cells are often elongated. Their extension is therefore at least 1.5 times greater in one spatial direction than in the other two spatial directions. For example, the length is greater than the width, and the width is greater than the thickness of the battery cell. The compression pad can be arranged on the outer surface of the battery cell in such a way that the flow channels run from one wide side of the battery cell, which is spanned by the width and thickness, to the opposite wide side. However, it can also be advantageous if the compression pad is arranged on the outer surface of the battery cell in such a way that the flow channels run from one long side of the battery cell, which is spanned by the length and thickness, to the opposite long side.

[0082] The invention also relates to a battery pack comprising a plurality of battery cells, wherein at least two battery cells are arranged at a distance from one another by means of at least one compression pad according to the invention.

[0083] A battery pack comprises at least two battery cells, wherein the plurality of battery cells can be arranged in particular in a housing or casing. The battery cells are held together by the housing or casing. The housing, or at least part of the housing, can also be formed by components of a vehicle, such as the chassis, body parts, the underbody, or a supporting frame.

[0084] In particular, the battery pack is configured to direct a fluid flow through the at least one flow channel of the compression pad.

[0085] For this purpose, it can be advantageous if the battery pack has external fluid flow ports that allow the fluid to be directed into the battery pack and through the flow channels. For this purpose, the flow channels can be connected to the battery pack or the fluid flow ports.

[0086] However, it is also conceivable that the battery pack has feedthroughs for the flow channels so that the flow channels can be connected, for example, outside a housing of the battery pack so that a fluid can be guided through the flow channels.

[0087] The invention further relates to a vehicle which has at least one of the battery packs described above with at least one compression pad according to the invention.

[0088] In particular, the vehicle is configured to conduct a fluid flow through the at least one flow channel of the compression pad. For this purpose, the vehicle may have a cooling system configured to cool the battery pack or battery cells by conducting a fluid through the flow channels of the compression pad.

[0089] To supply the battery pack with fluid, the vehicle can be equipped with fluid outlets and fluid inlets. The inlets and outlets can correspond to the battery pack's fluid flow connections or be connected to the flow channels themselves.

[0090] The invention is explained below using exemplary embodiments and schematic drawings. Herein:

[0091] Figure 1 shows two spacer layers that can be arranged on top of one another with a first variant of recesses,

[0092] Figure 2 shows a compression pad with the two spacer layers arranged on top of each other from Fig. 1,

[0093] Figure 3 shows two spacer layers that can be arranged on top of one another with a second variant of recesses,

[0094] Figure 4 shows a compression pad with the two spacer layers arranged on top of each other from Fig. 3,

[0095] Figure 5 shows two spacer layers that can be arranged on top of one another with a third variant of recesses,

[0096] Figure 6a shows a compression pad with the two spacer layers arranged on top of each other from Fig. 4,

[0097] Figure 6b shows the compression pad from Fig. 6a to illustrate the flow channels with the flow directions through the flow channels indicated.

[0098] Figure 1 shows two spacer layers 2 that can be arranged on top of one another, with a first variant of introduced recesses 7. For this purpose, the first spacer layer 2 with its recesses 7 is shown on the left in Fig. 1, and the second spacer layer 3 with its recesses 7 is shown on the right in Fig. 1. "Arrangable" in the context of the present invention means that the compression pads are intended to be arranged on top of one another in order to form the at least one flow path in this way.

[0099] The spacer layers 2, 3 are flat and have a length L, a width B, and a thickness D not shown here due to the two-dimensional representation. The spacer layers 2, 3 each have a first side surface 5 (the upper sides of the spacer layers 2, 3 shown in Fig. 1) and a second side surface 6 (the back sides of the spacer layers 2, 3 not shown in Fig. 1), which are each spanned by the length L and the width B.

[0100] The recesses 7 extend from the first side surface 5 to the second side surface 6 and are formed as continuous recesses 7 in the spacer layers 2, 3. They can therefore be formed in the flat spacer layers 2, 3 by punching or laser cutting.

[0101] The shapes of the recesses 7 are designed as parts of a meander and are arranged offset from one another such that, when the two spacer layers 2, 3 are arranged one on top of the other, a single, continuous, meander-shaped flow channel 4 is formed (see Fig. 2), through which a fluid can be conducted. The fluid follows a flow direction along the flow channel 4. The recesses 7 of the first spacer layer 2 always alternate with the recesses 7 of the second spacer layer 3 to form the flow channel 4.

[0102] Figure 2 shows a compression pad 1 with the two spacer layers 2, 3 from Fig. 1 arranged one on top of the other. For this purpose, the second spacer layer 3 is arranged with its first side surface 5 on the second side surface 6 of the first spacer layer 2. The two side surfaces 5, 6 arranged one on top of the other form a contact surface 8.

[0103] To form the meandering flow channel 4, one end of each recess 7 and the beginning of the next recess 7 overlap. This applies to all recesses 7 except for the first recess 7 (Fig. 1, recess 7 on the far left of the first spacer layer 2) and the last recess 2 (Fig. 1, recess 7 on the far right of the second spacer layer 3). Here, the beginning of the first recess 7 serves as the inlet of the fluid via a flow channel inlet 9, and the end of the last recess 7 serves as the outlet of the fluid via a flow channel outlet 10.

[0104] The recesses 7 of the second spacer layer 3 are covered by the first spacer layer 2, so that the recesses 7 of the second spacer layer 3 are only indicated by dashed lines.

[0105] The meandering flow channel 4 is distributed evenly over the compression pad 1 or evenly over the side surfaces 5, 6, so that the fluid reaches all areas of the compression pad 1 as evenly as possible.

[0106] Once the fluid has flowed through a recess 7 of the first spacer layer 2 on one side of the contact surface 8, it flows to the other side of the contact surface 8 into a recess 7 of the second spacer layer 3. The subsequent recess 7 in the flow channel 4 is again located in the first spacer layer 2 on one side of the contact surface 8. This change continues until the end of the flow channel 4.

[0107] The flow channel 4 runs from one longitudinal side LSI to an opposite longitudinal side LS2 of the compression pad 1, wherein the longitudinal sides LSI, LS2 are each spanned by the length L and the thickness D.

[0108] Figure 3 shows two spacer layers 2, 3 that can be arranged on top of one another with a second variant of recesses 7. The structure essentially corresponds to the structure of the spacer layers 2, 3 from Fig. 1 and correspondingly to the structure of the compression pad 1 from Fig. 2. Only, instead of a single flow channel 4, four flow channels 4 are now arranged analogously.

[0109] Figure 4 shows a compression pad 1 with the two spacer layers 2, 3 from Fig. 3 arranged on top of one another. Here, it is clearly visible how the four flow channels 4 run in a meandering manner and are evenly distributed across the compression pad 1. Figure 5 shows two spacer layers 2, 3 that can be arranged on top of one another with a third variant of recesses 7. In this variant, the recesses 7 are designed as circular recesses 7.

[0110] For this purpose, the recesses 7 are arranged in a substantially regular pattern on the spacer layers 2, 3. However, the flow channel inlet 9 and the flow channel outlet 10 deviate from the regular pattern in order to realize the individual inlets and outlets of the individual flow channels 4.

[0111] For reasons of clarity, the recesses 7 are shown in Figs. 5, 6a and 6b only on the left half of the spacer layers 2, 3.

[0112] Compared to the pattern of the first spacer layer 2, the pattern of the second spacer layer 3 is arranged offset, so that when the two spacer layers 2, 3 are arranged one above the other to form the compression pad 1, several flow channels 4 can be formed.

[0113] Figure 6a shows a compression pad 1 with the two spacer layers 2, 3 from Fig. 4 arranged one on top of the other. To form a flow channel 4, the circular recesses 7 partially overlap alternately with the contact surface 8, so that initially a continuous inlet area forms after the flow channel inlet 9, which then divides into four parallel flow channels 4 (see Fig. 6b). Due to the alternating recesses 7 of the two spacer layers 2, 3 along the respective flow channels 4, the fluid always flows back and forth between the spacer layers 2, 3 along the flow direction.

[0114] Figure 6b shows the compression pad 1 from Fig. 6a to illustrate the flow channels 4, with the flow directions through the flow channels 4 indicated. After a common inlet area, the four flow channels 4 divide into individual, no longer connected channels. List of reference symbols

[0115] 1 compression pad

[0116] 2 first spacer layer

[0117] 3 second spacer layer

[0118] 4 flow channel

[0119] 5 first side surface

[0120] 6 second side surface

[0121] 7 recesses

[0122] 8 Contact surface

[0123] 9 Flow channel entrance

[0124] 10 Flow channel outlet

[0125] B Width

[0126] D Thickness

[0127] L length

[0128] BS1 Broadside 1

[0129] BS2 Broadside 2

[0130] LSI long side 1

[0131] LS2 long side 2

Claims

Patent claims 1. Compression pad (1) for the spaced arrangement of battery cells in a battery pack, comprising a first planar spacer layer (2) and a second planar spacer layer (3), each having a length (L), a width (B) and a thickness (D), wherein the length (L) and the width (B) are each a multiple of the thickness (D), wherein the spacer layers (2, 3) each have a first side surface (5) and a second side surface (6), which are each spanned by the length (L) and the width (B), wherein the second spacer layer (3) is arranged on the first spacer layer (2) such that a side surface (5, 6) of the first spacer layer (2) and a side surface (5, 6) of the second spacer layer (3) coincide and form a contact surface (8) between the two spacer layers (2, 3), characterized in that both the first spacer layer (2) and the second spacer layer (3) have at least one recess (7),which each extend from the first side surface (5) to the second side surface (6), and wherein the first spacer layer (2) is arranged on the second spacer layer (3) and / or the recesses (7) are arranged on the spacer layers (2, 3) in such a way that the recesses (7) of the first and second spacer layers (2, 3) partially overlap, so that at least one of the recesses (7) of the first spacer layer (2) and at least one of the recesses (7) of the second spacer layer (3) form at least one continuous flow channel (4) through the compression pad (1) for fluid transport.

2. Compression pad (1) according to the preceding claim, characterized in that at least one of the spacer layers (2, 3) is designed as an elastic compression layer which is designed to support expansion and contraction of the battery cells.

3. Compression pad (1) according to the preceding claim, characterized in that both spacer layers (2, 3) are each designed as an elastic compression layer.

4. Compression pad (1) according to one of the two preceding claims, characterized in that at least one of the compression layers is formed from a foam, preferably from a PO foam, more preferably from a cross-linked PO foam.

5. Compression pad (1) according to one of the three preceding claims, characterized in that at least one of the compression layers comprises PUR foam, preferably compressed PUR foam.

6. Compression pad (1) according to one of the four preceding claims, characterized in that at least one of the compression layers comprises high-temperature foam, preferably melamine resin foam.

7. Compression pad (1) according to one of the five preceding claims, characterized in that at least one of the compression layers comprises a non-foamed material, preferably an elastomer rubber.

8. Compression pad (1) according to one of the preceding claims, characterized in that the spacer layers (2, 3) each have a plurality of recesses (7), and the plurality of recesses (7) of the first spacer layer (2) and the plurality of recesses (7) of the second spacer layer (3) are arranged such that in each case a recess (7) of the first spacer layer (2) and a recess (7) of the second spacer layer (3) alternately form a part of the flow channel (4) along a flow direction through the flow channel (4).

9. Compression pad (1) according to one of the preceding claims, characterized in that the at least one flow channel (4) runs from a first longitudinal side (LSI) of the compression pad (1) to an opposite second longitudinal side (LS2) of the compression pad (1), and / or from a first broad side (BS1) of the compression pad (1) to an opposite second broad side (BS2) of the compression pad (1), so that the fluid can be transported from the first longitudinal side (LSI) to the opposite second longitudinal side (LS2) and / or from the first broad side (BS1) to the opposite second broad side (BS2).

10. Compression pad (1) according to one of the preceding claims, characterized in that the compression pad (1) has a plurality of flow channels (4) which are arranged in the compression pad (1) in such a way that the individual flow channels (4) are fluidically connected to one another via the recesses (7).

11. Compression pad (1) according to one of the preceding claims, characterized in that the compression pad (1) has a plurality of flow channels (4), and the flow channels (4) are arranged in the compression pad (1) distributed uniformly over the contact surface (8).

12. Compression pad (1) according to the preceding claim, characterized in that the flow channels (4) run meandering through the compression pad (1).

13. Compression pad (1) according to one of the preceding claims, characterized in that the compression pad (1) has a plurality of flow channels (4), and the flow channels (4) are interconnected by recesses (7), wherein the flow channels (4) and recesses (7) are arranged in such a way that a permeable network structure over at least part of the contact surface (8).

14. Compression pad (1) according to one of the preceding claims, characterized in that the compression pad (1) has a plurality of flow channels (4), and the flow channels (4) are arranged crossing one another, so that a flow-through network structure is formed over at least part of the contact surface (8).

15. Compression pad (1) according to one of claims 1 to 9, 11, or 12, characterized in that the compression pad (1) has a plurality of flow channels (4) which are arranged in the compression pad (1) in such a way that the individual flow channels (1) are fluidically separated from one another.

16. Compression pad (1) according to one of the preceding claims, characterized in that the compression pad (1) has at least one flame-retardant and / or thermally insulating protective layer which is arranged on a side surface (5, 6) of the spacer layers (2, 3) facing away from the contact surface (8).

17. Compression pad (1) according to the preceding claim, characterized in that the compression pad (1) has two protective layers which are arranged on the two side surfaces (5, 6) of the spacer layers (2, 3) facing away from the contact surface (8).

18. Compression pad (1) according to one of the two preceding claims, characterized in that the respective protective layers comprise a layer of a mineral-based material, preferably mica.

19. Compression pad (1) according to one of the preceding claims, characterized in that at least one spacer layer (2, 3) has a plurality of macroscopic regions with different compressive stiffnesses extending on the first and / or second side surface (5, 6), wherein the compressive stiffnesses are preferably measured in the orthogonal direction to the first and / or second side surface (5, 6), and the at least one spacer layer (2, 3) has, in particular, recesses (7) in a different number and / or recesses (7) of different sizes in the different regions to create the regions with different compressive stiffnesses.

20. Battery cell with a compression pad (1) according to one of the preceding claims, characterized in that the compression pad (1) is arranged on an outer surface of the battery cell and is designed for the spaced arrangement of the battery cell from another battery cell in a battery pack.

21. Battery pack comprising a plurality of battery cells, characterized in that at least two battery cells are arranged at a distance from one another by means of at least one compression pad (1) according to one of claims 1 to 19.

22. Battery pack according to the preceding claim, characterized in that the battery pack is designed to conduct a fluid flow through the at least one flow channel (4).

23. Vehicle, characterized in that the vehicle has a battery pack according to one of the two preceding claims.

24. Vehicle according to the preceding claim, characterized in that the vehicle is designed to direct a fluid flow through the at least to guide a flow channel (4).

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