Method for manufacturing an electrode of a battery

Abstract

The invention relates to a method (32) for producing an electrode (16) for a battery (14), wherein a metal foil (24) is provided, which is provided with a layer (28) containing an active material, wherein the edge (30) of the metal foil (24) is free of the layer (28). A carrier tape (50) is applied to the edge (30), and the metal foil (24) with the layer (28) and the carrier tape (50) is calendered. The carrier tape (50) is separated from the metal foil (24). The invention also relates to a production device (34).

Description

Technical Field

[0001] The present invention relates to a method for producing an electrode for a battery and also to a production plant operated according to the method. Background Art

[0002] Motor vehicles are increasingly being driven at least partially by electric motors, thus being designed as electric or hybrid vehicles. High-voltage batteries, which have a plurality of individual batteries (also referred to as cells), are often used to power the electric motors. These cells are electrically connected in series and / or in parallel, so that the voltage present at the high-voltage battery corresponds to a multiple of the voltage provided by each of the batteries.

[0003] Each battery has an anode, a cathode, a separator arranged between them, and an electrolyte with freely movable charge carriers. A liquid is used as such an electrolyte, for example. In an alternative embodiment, the battery is designed as a solid-state battery, and the electrolyte is present as a solid. The anode and cathode that constitute the battery's electrodes typically include a carrier that acts as a current collector. Active materials are typically fixed to this carrier, which are components of a layer applied to the carrier. It is possible for the electrolyte to already be present in the layer or to be added later. However, at least the active material is suitable for absorbing working ions, such as lithium ions. Depending on the use as anode and cathode, different materials for the carrier and different types of layer materials are used. To make it easier to manufacture the anode and cathode, the layers are applied to the carrier in an at least partially liquefied state and distributed there using a scraper. This is then followed by calendering to achieve a precisely defined thickness for the layer and, therefore, the electrode.

[0004] To enable electrical contact with the electrodes, the carrier is free of layers in at least a certain section, and electrical contact is established in this section. For example, layers are partially removed for this purpose, which, however, requires additional manufacturing steps. This also ensures that the carrier is not damaged. Therefore, the carrier is typically not fully layered, and areas intended for electrical contact remain free of layers.

[0005] Therefore, calendering is performed with a carrier that is only partially coated. Here, the calender applies force to the carrier only via the layers, which is thereby at least partially plastically deformed there. In contrast, the parts of the carrier without the layers do not deform. Consequently, mechanical stresses develop between these parts, leading to wrinkles, so that the resulting electrode is not completely flat. It is therefore possible that the resulting electrode does not rest completely against the separator and that there is therefore no continuous electrical contact between them, which reduces the capacity of the battery. To avoid this, the maximum dimensions of the carrier are usually determined during the production of the electrode, at which the capacity remains approximately unchanged despite the wrinkles that form. Consequently, the continuous production of strips consisting of carrier and layers is not possible, from which the electrodes are subsequently cut.

[0006] However, in order to make the carrier usable as a coil (which can lead to increased production speed), the layers are applied to it discontinuously, thus forming a plurality of separate, spaced-apart regions provided with layers. This limits the maximum mechanical stresses that can occur. As a further alternative, for example, the carrier can be separated at certain locations to allow unloading there. However, all of this reduces production speed. Summary of the Invention

[0007] The object of the present invention is a particularly suitable method for producing an electrode for a battery and a particularly suitable production device, wherein the production speed is advantageously increased and / or the scrap is reduced.

[0008] According to the invention, this object is achieved with respect to the method by a method according to the invention for producing an electrode for a battery, and with respect to the production device by a production device according to the invention operated in accordance with the method.

[0009] This method is used to manufacture electrodes for batteries. The battery is, in particular, a galvanic element, which preferably has two electrodes, an anode and a cathode. A separator is suitably arranged between them in the assembled state. This method is used, for example, to manufacture only the anode or, for example, only the cathode. For example, only one of the electrodes of the battery is made according to this method, or preferably both are made according to this method. The battery preferably has an electrolyte that provides a large number of freely movable charge carriers (suitably ions). For example, the electrolyte is a component of the anode and / or cathode or is at least suitable for accumulating there and is therefore accommodated by it. The battery is, for example, a solid-state battery, whereby the electrolyte exists as a solid. However, it is particularly preferred that the electrolyte is liquid. For example, the battery is a secondary battery.

[0010] Preferably, the battery is a component of the motor vehicle in the prescribed state. For this purpose, the battery is suitable, and in particular, the battery is arranged and configured for this purpose. In the prescribed state, the battery is, for example, a component of and configured for the energy storage of the motor vehicle, which has a plurality of such cells / battery bodies. The batteries are in particular arranged in the housing of the energy storage and are electrically connected in parallel and / or in series with each other. Therefore, the voltage present at the energy storage is a multiple of the voltage provided by each of the batteries. Suitably, all batteries are structurally identical to each other here, which simplifies production. The housing is preferably made of metal, such as steel (e.g., stainless steel) or aluminum and / or by die-casting. In particular, the housing is designed to be closed. Suitably, the interface forming the connection of the energy storage is introduced into the housing. Here, the interface is electrically contacted with the battery, so that electrical energy can be fed in and / or removed from the battery from the outside of the energy storage, as long as the corresponding plug is inserted into the connection.

[0011] The motor vehicle is preferably land-based and preferably has multiple wheels, at least one, preferably multiple, or all of which are driven by a drive. Suitably, one, preferably multiple, of the wheels are designed to be controllable. This allows the motor vehicle to be moved independently of a specific roadway (e.g., rails or the like). It is advantageously possible to position the motor vehicle approximately arbitrarily on a roadway, particularly one made of asphalt, tarmac, or concrete. The motor vehicle is, for example, a commercial vehicle, such as a truck (LKW) or a bus. However, the motor vehicle is particularly preferably a passenger car (PKW).

[0012] The motor vehicle is suitably propelled forward by means of a drive. For example, the drive, in particular the main drive, is at least partially electrically designed, and the motor vehicle is, for example, an electric vehicle. The electric motor is operated, for example, by means of an energy storage device, which is suitably designed as a high-voltage battery. A DC voltage is suitably provided by means of the high-voltage battery, wherein this voltage is, for example, between 200 V and 800 V, and for example, approximately 400 V. Preferably, an electrical converter is arranged between the energy storage device and the electric motor, by means of which the power supply to the electric motor is adjusted. In an alternative embodiment, the drive additionally includes an internal combustion engine, so that the motor vehicle is designed as a hybrid vehicle. In an alternative embodiment, the low-voltage onboard electrical system of the motor vehicle is supplied by means of the energy storage device, and in particular a DC voltage of 12 V, 24 V, or 48 V is provided by means of the energy storage device.

[0013] In one alternative, the battery is part of a land transport vehicle, industrial equipment, or hand-held equipment (e.g., tools, especially electric screwdrivers). In another alternative, the battery is part of a power supply and is used there, for example, as a so-called backup battery. In another alternative, the battery is part of a portable device (e.g., a mobile phone or other wearable device). It is also possible to use such batteries in the field of camping, model making, or for other outdoor activities.

[0014] The method is configured to supply, or in particular provide, a metal foil provided with layers in a first working step. After the method is completed, the metal foil in particular forms the conductor (also referred to as a carrier) of the corresponding electrode. For example, copper foil is used as the metal foil when the anode is formed as the electrode. In contrast, if the cathode is used as the electrode, aluminum foil is preferably used as the metal foil. The metal foil is generally two-dimensional and has a relatively small thickness in the third dimension, in particular, the thickness is between 5 μm and 12 μm. For example, only one of the sides of the metal foil is provided with a layer, or particularly preferably both sides. However, the edges of the metal foil are free of layers. In this case, the edges include the edges of the metal foil and extend in particular from the edges of the metal foil in the direction of its central region. The edges are preferably continuous, and the area of the edges is preferably less than 20%, 10%, or 5% of the total area of the metal foil. In particular, the edges extend perpendicularly to the edges, for a maximum of 10% of the total extent of the metal foil perpendicular to the edges. If the metal foil is provided with layers on both sides, the edges are particularly free of layers on both sides. Preferably, the mutually free regions coincide with one another.

[0015] The thickness of the layer (i.e., its extension perpendicular to the main extension direction of the metal foil) is particularly between 40 μm and 100 μm, and for example, between 50 μm and 80 μm. The layer contains an active material. For example, lithium metal oxides, such as lithium cobalt(III) oxide (LiCoO2), NMC, NCA, or LFP are used as active materials. Alternatively, NMC622 or NMC811 are used as active materials. The choice of active material depends particularly on whether the electrode is a cathode or an anode. In addition to the active material, the layer may include, for example, a binder, a solvent, and / or a conductive additive (e.g., conductive carbon black).

[0016] In a further working step, the carrier tape is applied to the edge. In other words, the carrier tape is applied to the metal foil, in particular to the side on which the layer of metal foil is also located. If the metal foil is coated on both sides, the carrier tape is preferably applied accordingly to both sides of the metal foil, i.e. both edges. For example, the carrier tape is simply placed on the metal foil or fixed there (for example by means of an adhesive). However, it is particularly preferred that the carrier tape is at least partially pressed and / or materially connected to the metal foil, so that no additional components are required. It is also possible to carry out the application in relatively short time intervals. It is also possible to apply the carrier tape to the metal foil by means of corresponding rollers. For example, the carrier tape is partially heated before being applied to the edge, so that the adhesion at the edge is improved.

[0017] In the subsequent working step, the metal foil with the layer and carrier tape is calendered. In other words, the metal foil with the layer and carrier tape on it is moved through a calender. The calender, in particular, compresses the layer, thereby increasing its density and / or reducing its porosity. As a result, the thickness of the layer (i.e., its extension perpendicular to the metal foil) is reduced. To this end, a force is applied to the layer in the direction of the metal foil, in particular by means of any rollers of the calender. Since the carrier tape is also placed on the edge of the metal foil, the calender also applies force to this area of the metal foil, so that the metal foil is loaded approximately evenly by means of the calender. In other words, due to the application of force to the metal foil, the metal foil is at least partially deformed not only in the area of the layer but also in the area of the carrier tape, for example, perpendicular to the direction of movement of the metal foil through the calender, that is, in particular parallel to the axis of rotation of any rollers of the calender, and / or parallel to the direction of movement through the calender. As a result, essentially no mechanical stress is formed in the metal foil between the area provided with the layer and the area applied with the carrier tape.

[0018] In a subsequent working step, the carrier tape is separated from the metal foil. For example, the carrier tape is damaged for this purpose or, particularly preferably, is separated without damage. In particular, the force connection between the metal foil and the carrier tape is released, as well as any material connection. This makes it possible to reuse the carrier tape. Preferably, the carrier tape is designed to be closed and, after separation, is reapplied to the previously unrolled area of the metal foil, i.e., the edge of the metal foil. For example, the metal foil provided with the layer is then used as an electrode, wherein the metal foil acts as a current collector, also called a conductor or carrier. Alternatively, additional processing can be performed until the electrode is produced.

[0019] This method achieves uniform force application on the metal foil during rolling, resulting in essentially no mechanical stress. Consequently, electrodes produced in this manner also exhibit no wrinkles, resulting in a substantially completely flat electrode. This also enables further processing and reprocessing into batteries, which also reduces waste. After the carrier tape is separated at the edge, electrical contacting of the metal foil can be achieved there substantially unimpeded, thereby simplifying further processing of the electrode.

[0020] Preferably, a production device is used to carry out the method, comprising a supply device for a partially layered metal foil, a coating device for a carrier tape, a calender, and a separating device for the carrier tape, and is operated in particular according to the method. The layered metal foil is preferably provided as a coil, with the edges forming the longitudinal edges of the metal foil provided in this manner. It is therefore possible to provide a layer having approximately the same length as the metal foil, so that after the method is completed, a plurality of electrodes can be cut from the tape produced in this manner, in particular rewound onto rollers. This increases the speed of electrode production, and the maximum size of the electrode is not predetermined. In particular, the tape consisting of metal foil and layers is tensioned between the calenders, for which purpose a tensioning device is used. The tape is thus already partially tensioned in the area of the calender, thereby further preventing wrinkles.

[0021] For example, only one of the longitudinal edges of the metal foil forms an edge. However, it is particularly preferred that both longitudinal edges form edges, which are respectively free of layers. In this method, a corresponding carrier tape is applied to each of the edges. In this way, it is possible to achieve electrical contact between the electrodes on opposite sides and also facilitate further processing. In other words, it is particularly feasible to clamp the metal foil or the tape and / or the electrodes on two different sides in order to move them without damaging the layers. Preferably, the production device additionally includes a sealing unit, by means of which the metal foil is provided with layers, in particular if only the metal foil is rolled up on rollers where possible. Therefore, in particular before calendering, the layers are first applied, for example by means of pouring and / or a doctor blade or by means of printing.

[0022] For example, the carrier tape is arranged flush with the layer. The layer is thus at least partially stabilized by means of the carrier tape. However, it is particularly preferred that the carrier tape is applied to the edge at a distance from the layer. For example, further components are arranged between the carrier tape and the layer. However, it is particularly preferred that there are no further components in this area. Due to this distance, lateral expansion of the layer in the direction of the carrier tape is achieved during calendering when a force is applied to the layer in the direction of the metal foil. Thus, a wavy / corrugated structure or the carrier tape being surrounded by the layer is prevented, so that, on the one hand, the surface of the layer is relatively flat and, on the other hand, the carrier tape can be easily separated. Overall, the lateral expansion in the direction of the edge due to calendering is compensated by means of the spacer layer.

[0023] For example, this distance is selected so that even after calendering, even if the distance is now reduced, a free area is still formed between the layer and the carrier tape. This prevents damage to the layer even when the carrier tape is removed. For example, the distance is between 1 mm and 5 mm, and preferably between 2 mm and 3 mm. This provides sufficient space for the layer to expand, while the area of the metal foil that is not subject to stress during the calendering process is relatively small.

[0024] For example, the carrier tape is flush with the edge of the edge. However, it is particularly preferred that the carrier tape be applied to the edge so that its sides extend beyond the metal foil, that is, beyond the edge. To this end, the width of the carrier tape is appropriately selected accordingly. This overhang prevents mechanical stresses from forming in the edge region during calendering, and the forces acting on the metal foil are generally uniform overall.

[0025] For example, the thickness of the carrier tape is selected to be less than or equal to the thickness of the layer. Therefore, contact of the layer with the rollers of the calender is first achieved before it comes into contact with the carrier tape. For example, the thickness of the carrier tape, i.e., the extension perpendicular to the plane of extension of the metal foil, is approximately equal to the height that the metal foil and the layer should have after calendering. However, it is particularly preferred that the thickness of the carrier tape is selected to be greater than the thickness of the layer, so that it is correspondingly extended perpendicular to the plane of extension of the metal foil. Therefore, during calendering, force is first applied to the metal foil via the carrier tape in the edge region, so that the edge is deformed first. Only then does the force act on the metal foil via the layer. Therefore, the metal foil is first expanded outwards on the edge side, before other areas of the metal foil provided with the layer are deformed. As a result, the metal foil is deformed approximately without wrinkling.

[0026] Alternatively or in combination therewith, the calender, in particular any rollers of the calender, may have a step so that the calender rollers are first brought into mechanical contact with the layer before mechanical contact with the layer is achieved. This ensures that the force is first applied toward the edge of the metal foil. The calender is designed so that the surface speed of the rollers is preferably always the same despite the step, and the calender rollers are in particular two- or multi-piece. This prevents wrinkles in the metal foil caused by different surface speeds of the rollers.

[0027] For example, during calendering, the carrier tape is plastically deformed. However, it is particularly preferred that the material of the carrier tape is selected so that it only deforms elastically due to the calendering. In this way, the carrier tape can be reused, so that the same carrier tape can always be used when carrying out the method, thereby reducing manufacturing costs. It is particularly preferred that the carrier tape is made of rubber, for example of polystyrene-butadiene rubber ("SBR", "styrene-butadiene rubber"). It is therefore possible to flatten the thickness of the carrier tape by means of calendering to half or up to a quarter, wherein only elastic deformation is achieved. Similarly, the material used makes it easier to guide the carrier tape for application to the metal foil. Alternatively, the carrier tape can be made of polytetrafluoroethylene ("PTFE") or acrylic acid, for example. In this way, separation from the metal foil is facilitated, wherein the carrier tape, however, has a relatively high elasticity.

[0028] Alternatively, the carrier tape comprises a metal strip coated with plastic. This increases the robustness of the carrier tape. In particular, the use of stainless steel or titanium as the metal further increases the robustness. The plastic prevents other components from being damaged by the metal strip. In particular, the metal strip is coated with plastic on the side on which the metal foil is abutted. Particularly preferably, the metal strip is coated with plastic on both sides, so that the calender only comes into mechanical contact with the plastic, thus also avoiding damage from this. In particular, rubber or, particularly preferably, polyurethane (PUR) is used as the plastic. Consequently, relatively large elastic deformations of the carrier tape produced in this way are possible.

[0029] For example, the carrier tape is smooth on the side facing the metal foil. This simplifies the manufacture of the carrier tape and reduces wear and tear on the carrier tape. However, it is particularly preferred that the carrier tape has structures on the side facing the metal foil that extend obliquely, that is, in particular obliquely relative to the direction of the carrier tape and / or the metal foil. In particular, the structures extend obliquely relative to the direction in which the metal foil is moved through the calender. Preferably, these structures are formed by means of edges and / or reinforcing ribs, with these structures preferably being spaced apart from one another. Due to these structures, the adhesion of the carrier tape to the metal foil is improved, and they partially achieve a grip of the carrier tape and the metal foil, so that the metal foil deforms more when a force is applied to the carrier tape by means of the calender. In particular, the obliquely extending structures enable the edges to be moved away from the layer, so that the metal foil is pulled away from the layer starting from the edge. Therefore, due to these structures, the metal foil is tensioned when a force is applied by means of the calender, and wrinkling is more prevented. In particular, the structures are designed in such a way that the edge is moved away from the layer when a force is applied to the carrier.

[0030] Preferably, according to the method, the edge is pulled away from the layer in the plane of extension of the metal foil. The metal foil is thus stretched between the edge of the edge and the area provided with the layer. In particular, the pulling apart perpendicular to the direction of movement of the metal foil is achieved by a calender. For example, a possible structure of the carrier tape is used for this pulling apart. However, it is particularly preferred that additional devices of a possible production device are used, in particular a pulling apart device. Suitably, the pulling apart is achieved immediately after the calendering, so that any wrinkles that may exist due to the pulling apart are eliminated. Suitably, the pulling apart is carried out immediately after the carrier tape is removed from the metal foil, and the edge is preferably clamped by means of a possible pulling apart device. Since the carrier foil is removed, a substantially direct pulling apart of the edge is made possible and the load on the carrier tape is reduced.

[0031] For the purpose of stretching, rollers of a stretching device are used, for example, which act on the edge. In particular, the stretching device can additionally comprise further rollers which bear against the layer, thereby stabilizing the layer with the aid of the further rollers. For example, the rollers acting on the edge have a structure for stretching, or the rollers are partially displaced in the stretching direction. In particular, the rollers are at least partially covered with a plastic or made thereof, for example polyurethane. This prevents damage to the metal foil. Alternatively or in combination therewith, the rollers acting on the edge have a helical shape and are in particular designed to be spirally shaped. In this way, continuous stretching of the edge from the layer is made possible when the strip made of the metal foil and the layer is moved through the stretching device. In particular, the helix or the remaining structure of the further rollers has a depth of between 0.5 mm and 1 mm, so that damage to the metal foil due to the structured surface of the stretching device is avoided.

[0032] For example, the metal foil can be completely provided with layers except for the edges. Alternatively, the middle region of the metal foil can also be free of layers. The middle region is preferably spaced apart from at least the longitudinal edges of the metal foil extending parallel to the direction of movement of the metal foil through the calender, and layers are preferably present between the middle region and these edges. According to this method, another carrier tape is applied to the middle region, which is also separated after calendering. In particular, the other carrier tape has the same structure as the carrier tape. This allows the use of identical parts, which reduces the manufacturing costs of the possible production device. The lack of a middle region makes it possible to produce a plurality of electrodes using a tape consisting of metal foil and layers and / or to wind these electrodes accordingly. This further increases the speed of electrode production. For example, there are a plurality of such middle regions, wherein, during production, a corresponding additional carrier tape is applied to each of the middle regions.

[0033] For example, the metal foil provided with the layer is heated before the carrier tape is applied. For example, the metal foil can be heated after the carrier tape is applied to the edge or during supply. However, it is particularly preferred that the heating be performed before the carrier tape is applied to the edge. This improves the adhesion of the carrier tape at the edge. Due to the heating, the metal foil is at least partially plastically deformed, in particular due to the additional, possible tensioning device. This further reduces the formation of wrinkles. Heating is preferably performed at a temperature between 80°C and 120°C. This prevents thermal damage to the layer and / or metal foil. For heating, the metal foil / layer is irradiated with infrared light or by induction. Alternatively, the metal foil provided with the layer is subjected to hot air or guided along heated rollers, for which purpose a heated liquid, in particular water or oil, is guided through the rollers. After calendering, in particular after the carrier tape is separated and the edge is possibly pulled apart by the layer, the tape is preferably cooled again to maintain the resulting deformation. This improves durability. Alternatively, the metal foil and / or the layer may not be heated, thereby facilitating the operation of a possible production device.

[0034] The production device is used to produce battery electrodes and has a supply device for a metal foil provided with layers. The edges of the metal foil are free of layers, wherein the edges extend, in particular, along and surround the edges of the metal foil. The edges are preferably longitudinal edges parallel to the direction of movement of the metal foil through the production device. For example, the supply device comprises a roller on which the metal foil provided with layers is wound.

[0035] In addition, the production device includes an application device for the carrier tape. In particular, the application device has rollers, by means of which the carrier tape can be guided and / or applied to the metal foil. In addition, the production device includes a calender and a separation device for the carrier tape. In particular, in the direction of movement of the metal foil through the production device, the supply device is arranged before the application device and before the calender and before the separation device, so that in the case of operation, the metal foil is first conveyed from the supply device to the application device and then conveyed via the calender to the separation device. In particular, the production device additionally has a conveying device, by means of which, for example, a tape consisting of metal foil and a layer is wound.

[0036] Furthermore, the production device operates according to the following method, wherein a metal foil provided with a layer containing an active material is supplied, wherein the edges of the metal foil are free of the layer. A supply device is used, in particular, for this purpose. Subsequently, a carrier tape is applied to the edge of the metal foil, the application device being used for the metal foil. Subsequently, the metal foil provided with the layer and the carrier tape is calendered using a calender, and the carrier tape is subsequently separated from the metal foil using a separating device. Suitably, a production device is used to carry out this method. In particular, the production device operates continuously, and the supply device in particular comprises rollers, on which at least the metal foil is wound.

[0037] The production device suitably has a control unit that is configured and / or set up for carrying out the method. Preferably, the production device also includes a measuring device with the aid of which the thickness of the strip formed from the metal foil and the layer is measured, wherein the measuring device is preferably connected to the separating device. Thus, in particular, the thickness is measured after the calendering process has ended. Depending on the determined thickness, in particular, the calender is adjusted. With the aid of the production device, a large number of different electrodes and / or metal foils can be produced / processed. For matching, only the corresponding carrier tapes must be selected and the calender must be adjusted. Further adjustment or replacement of the individual components is not necessary.

[0038] The present invention also relates to an electrode produced with the aid of a corresponding production device or according to the method, and a control unit for carrying out the method, which is then suitable for this purpose, in particular, configured and set for this purpose. The control unit comprises, for example, an application-specific integrated circuit (ASIC) or a microprocessor, which is suitably programmable. The control unit preferably includes a memory on which a computer program product is stored, which, when implemented by a computer, in particular a microprocessor, causes the method to be carried out. In particular, the present invention also relates to a corresponding computer program product.

[0039] The advantages and improvements described in connection with the method are also transferable to the production device / control unit / application / electrode and to one another and vice versa. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Next, embodiments of the present invention will be described in more detail with reference to the accompanying drawings.

[0041] Figure 1 A schematically simplified representation of a motor vehicle having a high-voltage battery with a plurality of cells is shown.

[0042] Figure 2 One of the cells of the battery is shown schematically in cross-section, comprising two electrodes,

[0043] Figure 3 A method for manufacturing one of the electrodes is shown,

[0044] Figure 4 A production plant with a calender is shown schematically in side view,

[0045] Figure 5-7 The calender is shown in section in different operating positions accordingly.

[0046] Figure 8 according to Figure 5 An alternative embodiment of a calender is shown,

[0047] Figure 9according to Figure 5 The stretching device of the production unit is shown,

[0048] Figure 10 A modification of the stretching device is shown in section.

[0049] Figure 11 An embodiment of a carrier tape is shown in a cross-sectional view.

[0050] Figure 12 Another embodiment of the carrier tape is shown in a top view.

[0051] Figure 13 according to Figure 4 An alternative embodiment of the production plant is shown, and

[0052] Figure 14 A development of an electrode during production is shown in a sectional view. DETAILED DESCRIPTION

[0053] Corresponding parts are provided with the same reference numerals in all the figures.

[0054] exist Figure 1 The figure schematically illustrates a simplified diagram of a motor vehicle 2 in the form of a passenger car (Pkw). The motor vehicle 2 has multiple wheels 4, at least some of which are driven by a drive 6 including an electric motor. Therefore, the motor vehicle 2 is an electric vehicle or a hybrid vehicle. Furthermore, the drive 6 includes a converter, by means of which the electric motor is powered. The converter of the drive 6 is in turn powered by an energy storage device 8 in the form of a high-voltage battery. To this end, the drive 6 is connected to a port 10 of the energy storage device 8, which is inserted into a housing 12 of the energy storage device 8 made of stainless steel. Within the housing 12 are arranged multiple batteries 14, two of which are shown. The batteries 14 are assembled into multiple modules (not shown). Here, the battery cells 14 of each module are partially connected electrically in series and in parallel with one another, and are arranged in a common housing. These modules are in electrical contact with one another, with some of the modules being connected electrically in series and others being connected electrically in parallel. The electrical components of the modules, and therefore also the battery cells 14, are in electrical contact with the port 10, enabling discharge of the battery cells 14 when the drive 6 is in operation. Due to the electrical interconnection, the voltage of 400 V provided at the interface 10 is a multiple of the voltage provided by batteries 14 of identical construction.

[0055] exist Figure 2 1 shows a cross-sectional view of one of the structurally identical cells 14. The cell has two electrodes 16 separated from one another by a separator 18. The two electrodes 16 and the separator 18 are stacked one on top of the other and are directly adjacent to one another. One of the electrodes 16 is an anode 20, while the remaining electrode 16 is a cathode 22.

[0056] The two electrodes 16 are constructed similarly to each other and each have a current collector (carrier, conductor) made of a metal foil 24. In the case of the anode 20, the metal foil 24 is a copper foil, and in the case of the cathode 22, the metal foil 24 is an aluminum foil. Each metal foil 24 is flat and has a thickness of 8 μm perpendicular to the corresponding extension plane. In addition, each metal foil 24 includes a body 26, which overlaps with each other and has approximately the same extension as the separator 18. On each body 26, a layer 28 is applied on both sides and contains active material. This application is carried out, for example, by means of casting or embossing. As the active material, NMC is used in one embodiment. In addition, each of the layers 28 includes a binder, not shown in detail, as well as a solvent and conductive carbon black. Here, the thickness of each of the layers 28 is approximately 60 μm.

[0057] Furthermore, each of the metal foils 24 has two edges 30, each of which projects on opposite sides of the corresponding layer 28 and is therefore arranged on opposite sides of each corresponding body 26. The edges 30 extend from the corresponding longitudinal edge of the corresponding metal foil 24 in the direction of the body 26 and each comprise between 2% and 10% of the area of the entire metal foil 24, in this example 5%. The corresponding layer 28 is not applied to the edges 30. In summary, each electrode 16 has a corresponding metal foil 24 provided with two layers 28, wherein the two edges 30 are free of layer 28.

[0058] exist Figure 3 A method 32 for producing an electrode 16 is shown, wherein different raw materials are used depending on the electrode 16, ie, whether it is an anode 20 or a cathode 22. For production, ie, for carrying out the method 32, different raw materials are used. Figure 4 The production device 34 shown in FIG is used. The production device 34 is therefore operated according to the method 32. For this purpose, the production device 34 has a control unit (not shown in detail) by means of which the individual components of the production device 34 are controlled and / or regulated.

[0059] In a first working step 36, a metal foil 24 is supplied by means of a supply device 38, which is provided with the corresponding layers 28 on both sides, with the edge 30 being free of the corresponding layers 28. The corresponding layers 28 are initially merely applied, i.e., applied by casting or embossing to the metal foil 24 and materially connected and / or glued thereto, thereby producing a tape 40. In other words, the tape 40 consists of the metal foil 24 and the two layers 28. The layers 28 are not yet compacted and have a relatively high porosity, for example due to the removal of solvent during the drying process of the corresponding layers 28.

[0060] The strip 40 is wound onto a roller 42 of the supply device 38 and unwound from the roller 42 along a movement direction 44, which is perpendicular to the axis of rotation and / or the arrangement direction of the roller 42. The edge 30 extends along the movement direction 44. The strip 40 is guided to a coating device 46, which has two coating rollers 48 on each side of the metal foil 24, of which only one is shown.

[0061] In a second working step 49, a carrier tape 50 is applied to each edge 30 by means of each application roller 48. In this case, two carrier tapes 50 are applied to one of the edges 30 on opposite sides of the metal foil 24 by means of two application rollers 48. Thus, two carrier tapes 50 are associated with each of the edges 30, and a metal foil 24 is located between each of the two carrier tapes 50.

[0062] By means of each applicator roller 48, a respective carrier tape 50 made of rubber, ie SBR (polystyrene butadiene rubber), is pressed onto the metal foil 24 so that it adheres there, as in Figure 5 4 . As shown in the cross-section perpendicular to the direction of movement 44 , the carrier tape 50 is applied to the respective layer by means of the application roller 48 at a distance (or spacer, or Abstand) 52 of 3 mm, which is shown spaced apart from the tape 40 for a better overview. Furthermore, the carrier tape 50 projects beyond the respective associated edge 54, i.e., the longitudinal edge of the respective edge 30, i.e., also by 3 mm. The carrier tape 50 is thus applied to the respective associated edge 30 in such a way that it projects laterally beyond the metal foil 24 . The thickness of the carrier tape 50 , i.e., its extent perpendicular to the metal foil 24 , is selected to be greater than the thickness of the respective layer 28 , so that the carrier tape 50 projects beyond the layer 28 applied to the same side of the metal foil 24 .

[0063] In the subsequent third working step 56, the belt 40, onto which the carrier tape 50 is applied, is guided through a tensioning device 58 and a calender 60. The tensioning device 58 has two first tensioning rollers 62, which are located upstream of the calender 60 in the direction of movement 44 and are arranged on opposite sides of the belt 40. Similarly, the tensioning device 58 has two second tensioning rollers 64, which are also arranged on opposite sides of the belt 40 and downstream of the calender 60 in the direction of movement 44. The calender 60 includes two calender rollers 66, through which the belt 40 with the carrier tape 50 is guided. It is possible to vary the spacing of the calender rollers 66 relative to the belt 40.

[0064] The belt 40 and the carrier belt 50 are tensioned by means of the tensioning rollers 62, 64 so that they do not sag between the first tensioning roller 62 and the second tensioning roller 64. A force is exerted by means of the first tensioning roller 62 against the direction of movement 44 and by means of the second tensioning roller 64 in the direction of movement 44 toward the belt 40 and the carrier belt 50, so that no wrinkles are formed in the belt 40 and the carrier belt 50.

[0065] By means of the calender rollers 66, a force is generated perpendicularly to the metal foil 24 and directed towards the strip 40. Figure 6 As shown in the cross-section through the calender 60 and two rotatably supported calender rollers 66 perpendicular to the longitudinal direction 44, the layers 28 are compressed. Consequently, they are stretched at least partially in the direction of the corresponding carrier strip 50, that is, perpendicular to the direction of movement 44, thereby reducing each spacing 52. Due to the application of force by the calender rollers 66, the metal foil 24 is stretched not only in the direction of movement 44 but also perpendicular thereto, with the force being introduced via the layers 28. Furthermore, the force is introduced via the carrier strip 50, that is, toward the edge 30 of the metal foil 24. Because the carrier strip 50 is thicker than the corresponding layer 28 and also protrudes beyond the corresponding edge 54, upon contact with the calender rollers 66, the edge 30 of the metal foil 24 is deformed first, followed by the body 26, while wrinkling at the edge 54 is prevented by this extension.

[0066] Due to the elasticity of the carrier belt 50, it stretches again after leaving the calender 60 and passing through the second tensioning roller 64, as shown in FIG. Figure 7 , wherein the second tensioning roller 64 is shown spaced apart from the belt 40. However, for tensioning the belt 40, it is also in mechanical contact with the carrier belt 50 and the layer 28, just like the first tensioning roller 62. However, the density of the layer 28 is increased by means of the calender 60, so that it has a small thickness and is at least partially pressed into the gap 52 that originally existed between the carrier belt 50 and the layer 28.

[0067] exist Figure 8 An alternative embodiment of a calender 60 is shown in FIG. Here, the carrier tape 50 has a relatively large thickness, which simplifies the application to the metal foil 24. To prevent damage to the metal foil 24 due to the forces exerted on it during its passage through the calender 60, the calender rollers 66 each have two steps 68, allowing them to be adapted to different thicknesses. The steps 68 are selected so that the same forces are exerted on the metal foil 24 via the carrier tape 50 and the layer 28, resulting in a substantially uniform deformation of the metal foil 24 by means of the calender 60. As in the previous embodiment, the only region where no force is directly applied is the distance 52, which is, however, selected to be relatively small.

[0068] In the following fourth working step 70, the carrier strip 50 is separated from the metal foil 24 by means of a separating device 72. The separating device 72 has four wedges, wherein each carrier strip 50 is associated with one of the wedges 74, of which only two are shown. The carrier strips 50 are then guided to the correspondingly associated coating rollers 48, i.e., the coating devices 46, by means of a plurality of guide rollers 76. The guide rollers 76 ensure that the respective carrier strip 50 is sufficiently tensioned, thereby preventing loading of the carrier strip 50 and / or wrinkling thereof.

[0069] The metal foil 24 provided with the calendered layer 28 is guided in the direction of movement 44 to a stretching device 78 which stretches the metal foil 24 in the direction of movement 44. Figure 9 is shown in a top view along the direction of movement 44. In a fifth processing step 79, each edge 30 is pulled away from the layer 28, and thus the body 26 of the metal foil 24, in the plane of extension of the metal foil 24, using a stretching device 78. The force acting on the respective edge 30 by the stretching device 78 is perpendicular to the direction of movement 44. To this end, the stretching device 78 includes four rollers 80 made of plastic and each having a plurality of structures 82, i.e., ribs, on its surface. Two of the rollers 80 are located on opposite sides of the metal foil 24, and two of the rollers 80 are associated with each edge 30. As the strip 40 is guided through the stretching device 78, the rollers 80 rest against the edges 30 in a force-fitting manner, with each edge 30 being guided between two of the rollers 80. The structures 82 are selected so that the rotation of the rollers 80 pulls the edge 30 away from the body 26. It is stabilized via the layer 28 by means of two further rollers 84 of the stretching device 78 which are located on opposite sides of the metal foil 24 and are made of aluminum. For this purpose, the further rollers 84 each rest against the layer 28 in a force-fitting manner.

[0070] The strip 40 processed in this manner is then passed through a measuring device 86, with the aid of which the thickness of the layer 28, that is, the thickness of the strip 40, is measured. The calender 60 is adjusted based on the thickness determined by the measuring device 86. If the thickness is too great compared to the desired value, the calender rollers 66 are moved toward each other, thereby compressing the layer 28 to a greater extent. On the other hand, if the thickness is too small, the calender rollers 66 are spaced apart from each other.

[0071] In a sixth working step, the metal foil 24 provided with the compressed layer 28, i.e., the tape 40, is guided to a discharge device 90 having a further roller 92. The tape 40 is wound onto the further roller 92 for storage. In a working step not shown in detail, the tape 40 is suitably separated by the further roller 92 or by means of a cutting device before being wound onto the further roller 92, thereby completing the production of the electrode 16.

[0072] exist Figure 10 1 shows a variant of one of the rollers 80 of the stretching device 78 . The roller 80 does not have a structure 82 but is formed in a spiral shape, wherein it is moved away from the layer 28 while engaging in the edge 30 with this spiral.

[0073] exist Figure 11 , an alternative embodiment of a carrier tape 50 is shown in a cross-section perpendicular to the direction of movement 44. It comprises a metal tape 94 made of stainless steel. The metal tape 94 is coated on both sides with plastic 96, with polyurethane being used as the plastic 96. Such a carrier tape 94 is relatively strong and, due to the plastic 96, prevents damage to the metal foil 24 and the guide rollers 76.

[0074] exist Figure 12 shows another embodiment of one of the carrier tapes 50 in a top view of the side of the metal foil 24. On the side facing the metal foil 24, the carrier tape 50 has structures 98, i.e., corresponding depressions or edges, extending obliquely to the direction of movement 44. With the aid of structures 98, the edge 30 is pulled away from the layer 28 by applying force using the calender 60 and the tensioning device 58. In this case, it is possible to omit the tensioning device 78. Alternatively, it is provided in addition.

[0075] exist Figure 13 A variation of the production device 34 is shown in FIG. Figure 4 The variant shown in FIG. 4 includes a heating device 100, which is arranged in the direction of movement 44 between the roller 42, that is, the supply device 38, and the application device 46. The heating device 100 heats the metal foil 24 provided with the layer 28 to approximately 100°C before the carrier tape 50 is applied. To this end, hot air is blown onto the tape 40 by the heating device 100. The heating of the tape 40 improves the adhesion of the carrier tape 50. Furthermore, the metal foil 24 is partially plastically deformed, whereby any wrinkles that may have formed are smoothed out by the tensioning device 58, thereby reducing the force required for calendaring by the calendaring machine 60. Consequently, wrinkles are further reduced.

[0076] The production device 34 also has a cooling device 102 comprising two cooling rollers 104 arranged on opposite sides of the strip 40. The cooling device 102 is located downstream of the stretching device 78 in the direction of movement 44, and the cooling rollers 104 mechanically bear directly against the strip 40 and cool it to approximately 30° C. during operation. Consequently, the strip 40 has a constant temperature after passing through the cooling device 102. The thickness of the strip 40 is thus measured by the measuring device 86 at a correspondingly constant, or rather, constant, temperature.

[0077] exist Figure 14 shows another variant of the tape 40 in a cross-sectional view perpendicular to the direction of movement 44, and thus shows the electrode 16 during its production. In addition to the edge 30, the metal foil 24 is also free of the layer 28 on both sides in two central regions 106. These central regions 106 extend parallel to the edge 54 along the entire extent of the tape 40 in the direction of movement 44 and are spaced apart from one another by portions of the layer 28. Two further carrier tapes 108 of identical construction to the carrier tape 50 are applied to the central regions 106 of the metal foil 24 on each side using an application device 46. Thus, a total of four further carrier tapes 108 are present.

[0078] Therefore, a force is applied to the metal foil 24 in the middle region 106 by means of the calender 60, so that the metal foil 24 is loaded approximately the same by means of the calender 60. By means of the separating device 72, the further carrier tape 108 is also separated after calendering and is then also redirected to the coating device 46. In a variant solution not shown in detail, there is additionally a spacing 52 or another spacing between the further carrier tape 108 and the layer 28. For this purpose, the width of the further carrier tape 108 is selected accordingly. In one embodiment, the metal foil 24 is separated in the middle region 106 by means of the output device 90, so that a total of three electrodes 16 are produced simultaneously when the tape 40 is cut perpendicular to the direction of movement.

[0079] The present invention is not limited to the above-described exemplary embodiments. Rather, a person skilled in the art may also derive other variations of the present invention without departing from the scope of the present invention. In particular, all individual features described in connection with the various exemplary embodiments may also be combined with one another in other ways without departing from the scope of the present invention.

[0080] List of reference numerals:

[0081] 2 Motor vehicles

[0082] 4 wheels

[0083] 6 Drivers

[0084] 8 Energy storage device

[0085] 10 Interface

[0086] 12. Housing

[0087] 14 Batteries

[0088] 16 electrodes

[0089] 18 partition

[0090] 20 Anode

[0091] 22 cathode

[0092] 24 metal foil

[0093] 26 Subject

[0094] 28th floor

[0095] 30 Edge

[0096] 32 Methods

[0097] 34 Production equipment

[0098] 36 First working step

[0099] 38 Supply device

[0100] 40 belt

[0101] 42 Rollers

[0102] 44 Movement direction

[0103] 46 Application device

[0104] 48 Coating Roller

[0105] 49 Second working step

[0106] 50 carrier tape

[0107] 52 spacing

[0108] 54 Edges

[0109] 56 Third working step

[0110] 58 tensioning device

[0111] 60 calender

[0112] 62 First tensioning roller

[0113] 64 Second tensioning roller

[0114] 66 calender rolls

[0115] 68 steps

[0116] 70 Fourth working step

[0117] 72 Separation device

[0118] 74 Wedge

[0119] 76 guide rollers

[0120] 78 stretching device

[0121] 79 Fifth working step

[0122] 80 rollers

[0123] 82 Structure

[0124] 84 additional rollers

[0125] 86 Measuring device

[0126] 88 Sixth working step

[0127] 90 Output device

[0128] 92 Additional wheels

[0129] 94 Metal Strip

[0130] 96 Plastic

[0131] 98 Structure

[0132] 100 Heating device

[0133] 102 Cooling device

[0134] 104 cooling roller

[0135] 106 middle area.

Claims

1. A method (32) for producing an electrode (16) for a battery (14), wherein: - supplying a metal foil (24) provided with a layer (28) comprising an active material, wherein the edge (30) of the metal foil (24) is free of the layer (28), - applying a carrier tape (50) to the edge (30), wherein the thickness of the carrier tape (50) is selected to be greater than the thickness of the layer (28), and wherein the carrier tape (50) is applied to the edge (30) in such a way that it projects laterally beyond the metal foil (24), - calendering the metal foil (24) with said layer (28) and said carrier tape (50), and - separating the carrier tape (50) from the metal foil (24).

2. The method (32) according to claim 1, characterized in that The carrier tape (50) is applied to the edge (30) at a distance (52) from the layer (28).

3. The method (32) according to any one of claims 1 to 2, characterized in that A carrier tape (50) made of rubber is used.

4. The method (32) according to any one of claims 1 to 2, characterized in that A download belt (50) is used which has a metal belt (94) coated with plastic (96).

5. The method (32) according to any one of claims 1 to 2, characterized in that The carrier tape (50) is used, which has a structure (98) on the side facing the metal foil (24) that extends obliquely relative to the moving direction of the carrier tape (50).

6. The method (32) according to any one of claims 1 to 2, characterized in that The edge (30) is pulled away from the layer (28) in the plane of extension of the metal foil (24).

7. The method (32) according to any one of claims 1 to 2, characterized in that A further carrier tape (108) is applied to the central region (106) of the metal foil (24) that is free of the layer (28), and is separated after calendering.

8. The method (32) according to any one of claims 1 to 2, characterized in that The metal foil (24) provided with the layer (28) is heated before the application of the carrier tape (50).

9. A production device (34) comprising a supply device (38) for a metal foil (24) provided with a layer (28), a coating device (46) for a carrier tape (50), a calender (60) and a separation device (72) for the carrier tape (50), and the production device is operated according to the method (32) according to any one of claims 1 to 8.

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