Cell intermediate layer and method for producing a cell intermediate layer

Abstract

The invention relates to a cell intermediate layer (1) for an energy storage system (2), wherein the cell intermediate layer (1) is planar and has a first and a second main side (3, 4), characterised in that the cell intermediate layer (1) comprises at least one thermally insulating and compressible device (5) which is directed in such a way that the device (5) has a preferred direction from one main side (3) to the other main side (4). The invention also relates to a method for producing the cell intermediate layer (1) and to an energy storage system (2).

Description

[0001] Interstitial layer and method for producing an interstitial layer

[0002] Description

[0003] The invention relates to a cell interlayer for an energy storage system, wherein the cell interlayer comprises a device. The invention further relates to the use of such a cell interlayer in an energy storage system, a method for producing such a cell interlayer, and an energy storage system comprising such a cell interlayer.

[0004] Technical field

[0005] Energy storage systems, especially rechargeable electrical energy storage devices, are widely used, particularly in mobile systems. Rechargeable electrical energy storage devices are used, for example, in portable electronic devices such as smartphones and laptops. Furthermore, rechargeable electrical energy storage devices are increasingly used to provide energy for electric vehicles. A wide range of electric vehicles is conceivable, including not only passenger cars but also two-wheelers, vans, and trucks. Applications in robots, ships, aircraft, and mobile machinery are also possible. Other areas of application for electrical energy storage systems include stationary applications, such as backup systems, network stabilization systems, and the storage of electrical energy from renewable energy sources.A commonly used energy storage system is a rechargeable storage device in the form of a lithium-ion battery. Like other rechargeable electrical energy storage devices, lithium-ion batteries typically have several storage cells housed together in a single casing. These electrically connected storage cells are usually combined into a module.

[0006] The energy storage system is not limited to lithium-ion batteries. Other rechargeable battery systems, such as lithium-sulfur batteries, solid-state batteries, sodium-ion batteries, or metal-air batteries, are also conceivable energy storage systems. Furthermore, supercapacitors are also being considered as energy storage systems.

[0007] Rechargeable energy storage systems exhibit their highest electrical capacity and optimal power input and output only within a limited temperature range. Exceeding or falling below this optimal operating temperature range significantly reduces the storage system's capacity, power input, and power output, impairing its functionality. Furthermore, excessively high temperatures or temperature gradients within a cell can cause irreversible damage to the energy storage system. Therefore, both sustained temperature deviations from the ideal temperature and short-term temperature spikes should be strictly avoided. For example, lithium-ion batteries should not be subjected to sustained temperatures exceeding 50 °C or short-term temperature spikes exceeding 80 °C. Similarly, temperatures below -10 °C should be avoided.

[0008] Especially in passenger car applications, fast-charging capability is required for energy storage systems. The batteries forming an energy storage system should be fully or almost fully charged within a short time, for example, within 15 minutes. Due to the charging system's efficiency of approximately 90% to 95%, significant amounts of heat are released during the charging process, which must be dissipated. This heat is not released during normal operation. Therefore, the cooling system of the energy storage system must be designed to absorb the heat generated during charging.

[0009] Excessively high temperatures lead to irreversible damage to the energy storage system. In this context, the phenomenon known as thermal runaway is particularly prevalent in lithium-ion cells. This involves the rapid release of large amounts of thermal energy and gaseous degradation products, resulting in high pressure and temperatures within the cell casing. This effect is especially problematic for energy storage systems with high energy density and high-performance energy cells, such as those required for providing electrical energy in electric vehicles. As the energy levels increase and the power output of individual cells rise, so do the probability and intensity of thermal runaway.

[0010] Within a continuous cell, temperatures ranging from 600 °C to 1,200 °C can occur on the cell's housing wall for several minutes. The thermal insulation system between individual energy cells must withstand such stress and reduce energy transfer to neighboring cells to such an extent that the temperature load on these cells remains well below 120 °C. Limiting energy transfer to neighboring cells is crucial to prevent them from also experiencing thermal runaway.

[0011] Over their lifetime, lithium-ion battery cells undergo volume changes, with the volume increasing as their lifespan increases. In pouch cells, this manifests itself, for example, as bulging. In addition, there is a cyclical volume change with each charge and discharge cycle. This volume change of the battery cells must be compensated for. For this purpose, compression elements are placed between the battery cells to absorb the volume changes.

[0012] To compensate for volume changes in cells due to charging, discharging, and aging, as well as to reduce thermal propagation, for example in the event of a cell fire, cell spacers are used. These spacers are placed between two cells, for example in the traction batteries of an electric vehicle. Cell spacers (also called "cell spacer elements") are typically made of plates, fiber materials, or spacer strips. A conflict exists between good thermal insulation and high compressive stiffness with a high compression ratio. On the one hand, a high compression ratio and good thermal insulation are achieved through large material voids, thus requiring less material. On the other hand, high compressive stiffness is achieved through the use of stiff and usually highly thermally conductive materials, which require a significant amount of material.

[0013] State of the art

[0014] From DE 10 2018 113 815 A1 a cell interlayer is known which is arranged as a protective element between two cells of an energy storage system.

[0015] Description of the invention

[0016] The invention is based on the objective of providing a cell interlayer and a method for its production, which exhibits improved performance characteristics. The invention is further based on the objective of providing an energy storage system with such a cell interlayer, which exhibits improved performance characteristics.

[0017] The problem is solved by the features of claim 1. Advantageous embodiments are described in the dependent claims. The cell interlayer according to the invention for an energy storage system is designed in a plate-like form and has a first and a second main surface, wherein the cell interlayer comprises at least one thermally insulating and compressible device, which is oriented such that the device has a preferred direction from one main surface to the other main surface.

[0018] The intercellular layer is plate-shaped with a plate length, plate width, and plate thickness. The first and second main surfaces are formed as opposite flat sides. The distance between the first and second main surfaces corresponds to the plate thickness, which is smaller than the plate length and / or the plate width. The plate thickness is significantly smaller than the plate length and / or the plate width, in particular at least five times smaller.

[0019] In the unloaded state, no forces act on the main sides, while in the loaded state, forces act on the main sides, for example through expanding cells during the charging process, which are located on the main sides.

[0020] The interlayer exhibits properties including compression stiffness (also called compression strength), compression ratio (also called compression capacity or compression rate), and thermal insulation. These properties are described below in relation to each other. Compression stiffness, when a force is applied to compress the interlayer, is the ratio between the area-specific counterforce resulting from the applied force and the reduction in the interlayer's thickness. Compression stiffness thus characterizes the interlayer's resistance to deformation. The compression ratio is the ratio of the interlayer's thickness in the unloaded state to the thickness under maximum compression.A high compression ratio allows for an excellent representation of the required usable compression ratio from plate thickness BoL (Begin of Life) to EoL (End of Life) with the required stiffness. Thermal insulation refers to the reduction of heat energy transfer through the interlayer. The greater the thermal insulation, the less heat is transported through the interlayer from the first main layer to the second main layer per unit of time at the same temperature gradient.

[0021] The device can be designed, in particular, as a cavity. This cavity has a lower thermal conductivity than the material of the interlayer surrounding the device. The device thus exhibits thermally insulating properties with respect to the interlayer. The cavity can, in particular, contain a gas, which gives it compressible properties. Therefore, the device is compressible.

[0022] The arrangement of the intercellular space can influence its compressive stiffness. The cross-sectional area of ​​the intercellular space in a plane parallel to one of the main faces and through the arrangement is larger when the arrangement has a preferred direction from one main face to the other than when the arrangement is arbitrarily arranged, for example, when its preferred direction extends essentially parallel to one of the main faces. In contrast to the arbitrary arrangement, the compressive stiffness in the direction from one main face to the other is increased when the arrangement is defined, i.e., when it has a preferred direction from one main face to the other. A defined arrangement refers to the orientation of the arrangement within the intercellular space.The arrangement is oriented in a preferred direction, which corresponds to the direction from one main side to the other. From one main side to the other means from the first main side to the second main side, or from the second main side to the first main side. In an application of the cell interlayer in an energy storage system, this direction corresponds to the main loading direction.

[0023] The device encloses a volume that remains constant even with a specific, defined arrangement of the device. Likewise, the material fraction of the interlayer remains constant with the defined arrangement. The porosity, i.e., the ratio of the device's cavity volume to the total volume of the interlayer, therefore remains constant. Consequently, the heat conduction paths through the interlayer from one main side to the other do not change significantly, so a defined arrangement of the device has no, or only a minimally negative, impact on the thermal insulation properties of the interlayer. Likewise, the defined arrangement of the device has no, or only a minimally negative, impact on the compression ratio of the interlayer.

[0024] The devices are preferably designed as microstructures. Microstructures are understood to be structures with very small dimensions. Microstructures are not visible to the naked eye and can only be recognized as structures or patterns with an optical aid. These microstructures preferably have a size in the hundredths of a millimeter.

[0025] The volume formed by the device, in the form of a cavity, can be completely enclosed by the intercellular layer, for example in closed-cell foams. Alternatively, the volume can be partially enclosed by the intercellular layer, for example in open-cell foams, especially sponges.

[0026] The defined arrangement of the device thus allows for an increase in compression stiffness while maintaining the same thermal insulation properties and the same compression ratio of the interlayer. "Maintaining the same" here means that the corresponding properties do not change, or do not change significantly for the worse.

[0027] The device can be elongated and have a longitudinal axis, the device being arranged such that the longitudinal axis extends substantially from one main side towards the other main side. Elongated, as used in the invention, means that the extent of the device in a first direction, namely in the direction of the longitudinal axis, is greater than the extents in a second and third direction, the direction vectors of the three directions being orthogonal to each other. The device is therefore longer than it is tall and wider. The volume formed by the device can, for example, be lenticular, cigar-shaped, wedge-shaped, needle-shaped, or cylindrical. The elongated shape, combined with a constant volume and the simultaneous orientation of the longitudinal axis from one main side towards the other main side, increases the compressive strength of the intercellular layer.

[0028] The orientation angle between the longitudinal axis of the device and a surface normal of one of the main sides can be between 0° and 30°. Preferably, the orientation angle is between 0° and 20°, and particularly preferably between 0° and 10°. In particular, the longitudinal axis of the device is parallel to a surface normal of one of the main sides. The smaller the orientation angle, the greater the positive effect on the compression stiffness in the direction from one of the main sides to the other main side.

[0029] The intercellular layer can have several structures. Each of these structures has a volume. The ratio between the sum of the respective volumes of all structures and the volume of the intercellular layer, i.e., the porosity of the intercellular layer, is preferably between 30% and 70%, more preferably between 40% and 60%, and particularly preferably 50%. The structures can be in open-pore and / or closed-pore form.

[0030] The interlayer can have an orientation component, where the orientation component describes the ratio between features in the interlayer with a specific orientation angle and all features in the interlayer. The specific orientation angle can be between 0° and 30°. Preferably, the orientation angle is between 0° and 20°, more preferably between 0° and 10°. The orientation component can be more than 40%. Preferably, the orientation component is more than 60%, more preferably more than 80%. A high orientation component can further improve the compression stiffness in the direction from one of the main faces to the other main face.

[0031] The multiple devices can be arranged periodically within the interlayer material. The interlayer material can be a solid material. It is also conceivable that the interlayer material is a foam with randomly arranged pores, in which the devices are additionally arranged. The devices have a defined shape. This defined shape can be intentionally created. The devices with this shape are arranged in a defined pattern, whereby the pattern, in its entirety or parts thereof, is repeated multiple times. It is also conceivable that the devices are generated stochastically and arranged within the interlayer material. Such devices could, for example, be foams with closed-cell cavities or sponges with open-cell cavities.

[0032] The previously described intercellular layer can be produced by an intercellular layer production process comprising the following steps:

[0033] - Providing a foam blank;

[0034] - Foaming of the foam blank;

[0035] - Removal of the gas produced in the direction of one of the main sides of the interlayer, wherein a cavity formed by the gas constitutes at least one device.

[0036] By supplying and foaming the foam blank, the intercellular matrix undergoes a foaming process in the first two steps. This foaming process transforms the foam blank into a semi-finished product. The semi-finished product already has the plate-like shape of the final desired intercellular matrix. Subsequently, the gas generated during the foaming process is removed from the semi-finished product towards one of the main sides of the intercellular matrix. This process step is also known as "anisotropic forced foaming." The resulting gas forms a cavity that creates the device. Depending on the process conditions, the generated gas can form multiple cavities, which in turn form several devices.

[0037] The foaming of the foam blank can be carried out in a mechanically forced state of the semi-finished product. After the formation of the cavities created by the gases, the semi-finished product is depressurized to its application state, whereby the cavities retain their shape.

[0038] Alternatively, the previously described intercellular layer can be produced by an intercellular layer production process comprising the following steps:

[0039] - Providing raw material for the intercellular layer;

[0040] - Removal of material from the raw material, wherein a cavity created by the removed material forms at least one device.

[0041] The raw material for the intercellular spacer is in a plate-like form and essentially has the dimensions of the intercellular spacer to be produced. The material to be removed can be extracted in various ways to create a cavity. Directed punctures, cuts, or tears can be mechanically introduced into the raw material, for example, using needles or knives. Removal can also be chemically or physically induced, for example, by using a laser or by fillers that are activated in a subsequent process step, leaving a cavity. It is also conceivable that the cavity could be created by evaporation. The resulting cavity forms the device. The material removal process can be repeated multiple times to create several cavities. These cavities then form multiple devices.

[0042] Alternatively, the previously described intercellular layer can be produced by an intercellular layer production process comprising:

[0043] - Providing a raw material for the intercellular layer; introducing a volume particle defining a cavity into the raw material, the cavity forming a device.

[0044] The bulk particle can be introduced into the raw material in various ways, particularly by rolling. This process step is called "seeding." The cavity within the bulk particle forms the device. The insertion process can be repeated multiple times to introduce several bulk particles and thus multiple cavities. These cavities then form multiple devices.

[0045] The interlayer can comprise at least one first layer and at least one second layer. Advantageously, the first layer can include at least one feature, and / or the second layer can include at least one feature. Both the first and second layers are plate-shaped and each has two main faces. A main face of the first layer is arranged against a main face of the second layer, so that the first and second layers form a contact surface. Preferably, the first layer has a different number and / or configuration of the feature(s) compared to the second layer. The first or second layer can be essentially free of a feature. As a result, the first layer has different properties with respect to compression stiffness, compression ratio, and thermal insulation than the second layer.The combination of the first layer and the second layer determines the properties of the intercellular layer.

[0046] The interlayer can have multiple first layers and / or multiple second layers. The first and second layers can be arranged in a sandwich structure. The first and second layers can be arranged in a defined sequence. For example, the first and second layers can be arranged alternately, such as "First layer / Second layer / First layer". Alternatively, the first and second layers can be arranged in groups, such as "Two first layers / Three second layers / One first layer / One second layer". By selectively arranging the first and second layers, the properties of the entire interlayer can be precisely controlled. Furthermore, the properties of the interlayer can be selectively adjusted locally.For example, the first layers with low compression stiffness can be arranged near the surface (on one of the main sides) of the interlayer, while the second layers with high compression stiffness are arranged further away from the surface of the interlayer in order to achieve high deformability locally on the surface of the interlayer, whereas further away from the surface of the interlayer, i.e. in the interior of the interlayer, there is almost no deformability.

[0047] The previously described intercellular layer can be produced by an intercellular layer production process comprising the following steps:

[0048] - Deploying an initial layer;

[0049] - Provide a second layer;

[0050] - Arranging the first layer on the second layer, wherein the first layer and / or the second layer has at least one device.

[0051] One of the main sides of the first layer can be positioned against one of the main sides of the second layer. The first layer is then fixed to the second layer, for example by gluing. After gluing, the layers fixed together can be trimmed.

[0052] The described process steps can be repeated multiple times to produce an interlayer with several first and / or second layers. The first and / or second layers can be arranged accordingly to achieve the desired properties of the interlayer.

[0053] An advantageous embodiment of the invention provides that the first layer forms a first section of at least one device and the second layer forms a second section of the device. The first section of the device is configured as a first recess. The second section of the device is configured as a second recess. Preferably, the first section and the second section are arranged congruently in the first and second layers, such that the first section and the second section together form a device. The first section is arranged on one of the main sides of the first layer and the second section is arranged on one of the main sides of the second layer, with the respective main sides of the first and second layers being arranged adjacent to each other.

[0054] The first layer can contain the first section of each of several devices, and the second layer can contain the second section of each of the several devices. The first and second sections are arranged congruently in the first and second layers, so that together they form the several devices. The first sections are arranged on one of the main sides of the first layer, and the second sections are arranged on one of the main sides of the second layer, with the respective main sides of the first and second layers adjacent to each other.

[0055] The previously described intercellular layer can be produced by an intercellular layer production process comprising the following steps:

[0056] - Deploying an initial layer;

[0057] - Provide a second layer;

[0058] - Mechanical removal of material on a first side of the first layer, creating at least one first recess;

[0059] - Mechanical removal of material on a first side of the second layer, creating at least one second recess;

[0060] - Arranging the first and second layers, wherein the first side of the first layer is arranged on the first side of the second layer, such that the at least first recess and the at least second recess form at least one device.

[0061] Mechanical material removal is performed on one of the main sides of the first layer and on one of the main sides of the second layer. The resulting recesses are positioned on the first and second layers such that they interact when the layers are arranged, forming the device. The mechanical removal process can be repeated multiple times, so that material is removed from the first and second layers at several points. This creates multiple recesses. These recesses are then positioned so that they interact when the layers are arranged, forming the device. The first and second layers are subsequently fixed, for example, by gluing.

[0062] Furthermore, the invention relates to the use of a cell interlayer, as described above, in an energy storage system with multiple storage cells. Such energy storage systems are used, for example, in the automotive sector in passenger cars. The high energy densities required there, combined with a small space requirement, place special demands on the cell interlayers between the storage cells.

[0063] The problem underlying the invention is further solved by an energy storage system comprising at least two energy storage cells and at least one cell interlayer, wherein the cell interlayer is arranged between the energy storage cells, with one main side of the cell interlayer facing an energy storage cell.

[0064] The energy storage system can comprise multiple energy storage cells, with an interlayer layer positioned between each pair of adjacent energy storage cells. The first and second main faces of the interlayer layer are each assigned to one of the two adjacent energy storage cells.

[0065] Brief description of the drawing: An embodiment of the intercellular layer according to the invention is explained in more detail below with reference to the figures. These show, schematically:

[0066] Fig. 1 shows a sectional view of an intercellular layer with closed-pore features;

[0067] Fig. 2 shows a perspective view of a section of another intercellular layer with closed-pore and open-pore structures;

[0068] Fig. 3 shows a sectional view of another cell interlayer with closed-pore and open-pore structures produced by entry;

[0069] Fig. 4 shows a sectional view of another intercellular layer containing bulk particles;

[0070] Fig. 5 shows a sectional view of another two-layered intercellular space;

[0071] Fig. 6 shows a sectional view of a three-layered intercellular spacer;

[0072] Fig. 7 shows a sectional view of another two-layered intercellular layer with first and second sections;

[0073] Fig. 8 shows a sectional view of an energy storage system with cell interlayers.

[0074] Implementation of the invention

[0075] Figures 1 to 7 each show an interlayer cell according to the invention 1 for an energy storage system 2. The interlayer cell 1 shown in each figure is plate-shaped with a plate length, plate width, and plate thickness, and has a first main surface 3 and a second main surface 4. The interlayer cell 1 comprises several features 5 oriented from one of the main surfaces 3, 4 to the other. The first main surface 3 and the second main surface 4 are designed as opposite flat surfaces. The distance between the first main surface 3 and the second main surface 4 corresponds to the plate thickness, which is at least one order of magnitude smaller than the plate length and / or the plate width.

[0076] The intercellular layer 1 shown in each figure exhibits properties including compression stiffness, compression ratio, and thermal insulation. The compression stiffness of the intercellular layer is influenced by the structures 5, which are designed as microstructures. For clarity, the structures 5 are shown greatly enlarged in the figures.

[0077] The devices 5 each enclose a volume 6. In the embodiments shown in Figures 1, 4, 5, 6, and 7, the volumes 6 are in closed-pore form. In the embodiments shown in Figures 2 and 3, the volumes 6 are partly in open-pore and partly in closed-pore form. The ratio between the sum of the respective volumes 6 of all devices 5 and the volume of the intercellular layer 1, i.e., the porosity of the intercellular layer 1, is between 30% and 70%.

[0078] The devices 5 of the embodiments shown in Figures 4, 5, 6 and 7 have a defined configuration and are arranged periodically. The devices 5 of the embodiments shown in Figures 1 to 3 are generated and arranged stochastically.

[0079] In the embodiments shown in Figures 1, 2, 4, 6 and 7, the volumes 6 are lenticular in shape. In the embodiment shown in Figure 3, the volumes 6 are needle-shaped. In the embodiment shown in Figure 5, the volumes 6 are wedge-shaped.

[0080] The devices 5 are elongated and have a longitudinal axis L. The devices 5 are arranged such that the respective longitudinal axis L extends from one of the main sides 3, 4 towards the other main side 3, 4. The orientation angle 7 between the longitudinal axis L of the device 5 and a surface normal F of one of the main sides 3, 4 is between 0° and 30°. In the embodiments shown in Figures 1, 4, 5, 6 and 7, the longitudinal axes L of the devices 5 are parallel to a surface normal F of one of the main sides 3, 4, so that the orientation angle is 0° and is not shown in the figures. The embodiments of the cell interlayer 1 shown in Figures 1 and 2 are produced by a method for producing a cell interlayer 1 comprising the steps:

[0081] - Providing a foam blank;

[0082] - Foaming of the foam blank;

[0083] - Removal of the gas produced in the direction of one of the main sides 3, 4 of the cell interlayer 1, wherein a cavity formed by the gas forms at least one device 5.

[0084] The resulting gas forms cavities that constitute the devices 5.

[0085] The embodiment of the cell interlayer 1 shown in Figure 3 is produced by a method for producing a cell interlayer 1 comprising the steps:

[0086] - Providing raw material for the intercellular layer 1;

[0087] - Removal of material from the raw material, wherein a cavity created by the removed material forms the device 5.

[0088] Directed cracks were introduced into the raw material to create the cavities.

[0089] The embodiment of the cell interlayer 1 shown in Figure 4 is produced by a method for producing a cell interlayer 1 comprising the steps:

[0090] - Providing raw material for the intercellular layer 1;

[0091] - Introducing a volume particle 19 defining a cavity 18 into the raw material, wherein the cavity 18 forms a device 5.

[0092] The bulk particle 19 was introduced into the raw material by rolling. Other methods for introducing the bulk particle 19 are also conceivable, for example, other mixing processes known to those skilled in the art for the production of elastomer composites. The cavity 18 within the bulk particle 19 forms the device 5. The insertion process step was repeated several times to introduce multiple bulk particles 19 and thus multiple cavities 18. The cavities 18 then form multiple devices 5.

[0093] Figures 5, 6, and 7 each show an embodiment of the interlayer 1, in which the interlayer 1 is multilayered and comprises a first layer 8 and a second layer 9. Both the first layer 8 and the second layer 9 are plate-shaped and each have two main faces 10, 11. A main face 10 of the first layer 8 is arranged against a main face 11 of the second layer 9, so that the first layer 8 and the second layer 9 form a contact surface 12.

[0094] In the embodiments shown in Figures 5 and 6, the first layer comprises

[0095] The first layer 8 contains the features 5, and the second layer 9 is free of features 5. Therefore, the first layer 8 has different properties with respect to compression stiffness, compression ratio, and thermal insulation than the second layer 9. The combination of the first layer 8 and the second layer 9 results in the properties of the interlayer 1. In Figure 6, the interlayer 1 comprises a three-layer structure, consisting of two first layers 8 and one second layer 9. The first layers 8 and 9 are arranged in a sandwich structure, with the first layer 8 and the second layer 9 being separated.

[0096] 9 are arranged alternately. This means that the first layers 8, with low compression stiffness, are located near the surface of the interlayer 1, while the second layer 9, with high compression stiffness, is located further away from the surface of the interlayer 1 in order to achieve high deformability locally at the surface of the interlayer 1, whereas further away from the surface of the interlayer 1, i.e., in the interior of the interlayer 1, there is almost no deformability.

[0097] The embodiment of the cell interlayer 1 shown in Figure 5 is produced by a method for producing a cell interlayer 1 comprising the steps:

[0098] - Provision of an initial layer 8;

[0099] - Provide a second layer 9;

[0100] - Arrange the first layer 8 on the second layer 9. One of the main sides 10 of the first layer 8 will be positioned on one of the main sides 11 of the second layer 9. The first layer 8 will then be fixed to the second layer 9, for example by gluing. After gluing, the fixed layers 8 and 9 will be trimmed.

[0101] The embodiment of the cell interlayer 1 shown in Figure 6 is produced by a method for producing a cell interlayer 1 comprising the steps:

[0102] - Provision of an initial layer 8;

[0103] - Provide a second layer 9;

[0104] - Arranging the first layer 8 on the second layer 9;

[0105] - Provide another first layer 8;

[0106] - Arranging the further first layer 8 on the second layer 9;

[0107] One of the main pages 10 of the first layer 8 is positioned next to one of the main pages 11 of the second layer 9. Another main page 10 of the first layer 8 is positioned next to the other main page 11 of the second layer 9. The first layers 8 are then fixed to the second layer 9, for example by gluing. After gluing, the joined layers 8 and 9 are trimmed.

[0108] In Figure 7, the first layer 8 has first sections 13 of the devices, and the second layer 9 has second sections 14 of the devices 5. The first sections 13 of the devices 5 are configured as first recesses 15. The second sections 14 of the devices 5 are configured as second recesses 16. The first sections 13 and the second sections 14 are arranged congruently in the first and second layers 8 and 9, such that the first sections 13 and the second sections 14 together form the multiple devices 5. The first sections 13 are arranged on one of the main sides 10 of the first layer 8, and the second sections 14 are arranged on one of the main sides 11 of the second layer 9, with the respective main sides 10 and 11 of the first and second layers 8 and 9 being adjacent to each other. The embodiment of the cell interlayer 1 shown in Figure 7 is produced by a method for producing a cell interlayer 1 comprising the steps:

[0109] - Provision of an initial layer 8;

[0110] - Provide a second layer 9;

[0111] - Mechanical removal of material on a first side 10 of the first layer 8, creating a first recess 15;

[0112] - Mechanical removal of material on a first side 11 of the second layer 9, creating a second recess 16;

[0113] - Arranging the first and second layers 8, 9, wherein the first side 10 of the first layer 8 is arranged on the first side 11 of the second layer 9, so that the first recess 15 and the second recess 16 form the device 5.

[0114] The mechanical removal of material is carried out on one of the main sides 10 of the first layer 8 and on one of the main sides 11 of the second layer 9. The mechanical removal process is repeated several times so that material is removed from the first layer 8 and the second layer 9 at multiple locations. This creates several first and second recesses 15, 16. The multiple first and second recesses 15, 16 are positioned such that they interact with each other in the arrangement of the first and second layers 8, 9 and together form the multiple devices 5. The first layer 8 and the second layer 9 are then fixed, for example, by gluing.

[0115] The energy storage system 2 shown in Figure 8 comprises several energy storage cells 17, with an intermediate cell layer 1 arranged between each pair of adjacent energy storage cells 17. The first and second main faces 3, 4 of the intermediate cell layer 1 are each assigned to one of the two adjacent energy storage cells 17.

Claims

Patent claims 1. Cell interlayer (1 ) for an energy storage system (2), wherein the cell interlayer (1 ) is designed in a plate-like form and has a first and a second main surface (3, 4), characterized in that the cell interlayer (1 ) comprises at least one thermally insulating and compressible device (5) which is oriented such that the device (5) has a preferred direction from one main surface (3) to the other main surface (4).

2. Cell interlayer according to claim 1, characterized in that the device is elongated and has a longitudinal axis (L), wherein the device (5) is arranged such that the longitudinal axis (L) extends substantially from one main side (3) towards the other main side (4).

3. Cell interlayer according to claim 1 or 2, characterized in that the cell interlayer (1 ) comprises several devices (5).

4. Cell interlayer according to claim 3, characterized in that the devices (5) are periodically arranged in the material of the cell interlayer (1 ).

5. Cell interlayer according to claim 3, characterized in that the devices (5) are arranged stochastically in the material of the cell interlayer (1 ).

6. Cell interlayer according to one of claims 1 to 5, characterized in that the cell interlayer (1 ) has at least a first layer (8) and at least a second layer (9).

7. Cell interlayer according to claim 6, characterized in that the first layer (8) comprises at least one device (5) and / or that the second layer (9) comprises at least one device (5).

8. Cell interlayer according to claim 6, characterized in that the first layer (8) forms a first section (13) of at least one device (5) and the second layer (9) forms a second section (14) of the device (5).

9. Use of a cell interlayer (1 ) according to any one of claims 1 to 8 in an energy storage system (2).

10. Method for producing a cell interlayer according to one of the claims 1 to 5, encompassing the steps: - Providing a foam blank; - Foaming of the foam blank; - Removal of the gas produced in the direction of one of the main sides (3, 4) of the cell interlayer (1), wherein a cavity formed by the gas constitutes at least one device (5).

11. Method for producing a cell interlayer according to one of the claims 1 to 5, encompassing the steps: - Providing raw material for an intercellular layer (1); - Removal of material from the raw material, wherein a cavity created by the removed material forms at least one device (5).

12. Method for producing a cell interlayer according to one of the claims 1 to 5, encompassing the steps: - Providing raw material for an intercellular layer (1); - Introducing a volume particle (19) defining a cavity (18) into the raw material, wherein the cavity (18) forms a device (5).

13. Method for producing a cell interlayer according to claim 7, comprising the steps: - Provide a first layer (8); - Provide a second layer (9); - Arranging the first layer (8) on the second layer (9), wherein the first layer (8) and / or the second layer (9) has at least one device (5).

14. Method for producing a cell interlayer according to claim 8, comprising the steps: - Provide a first layer (8); - Provide a second layer (9); - Mechanical removal of material on a first side (10) of the first layer (8), creating at least one first recess (15); - Mechanical removal of material on a first side (11) of the second layer (9), resulting in at least one second recess (16); - Arranging the first and second layers (8, 9), with the first side (10) of the first layer (8) is arranged on the first side (11) of the second layer (9), so that the at least first recess (15) and the at least second recess (16) form at least one device (5).

15. Energy storage system (2) comprising at least two energy storage cells (17) and at least one cell interlayer (1 ) according to any one of claims 1 to 8, wherein the cell interlayer (1) is arranged between the energy storage cells (17), wherein a main side (3, 4) of the cell interlayer (1 ) is facing one energy storage cell (17).

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