Method for manufacturing electrodes for battery cells

Abstract

A method for producing an electrode (1) of a battery cell (2); wherein the method has at least the following steps: a) production of a coated carrier material (4) of the electrode (1) with an active material (3); b) loading of the coated carrier material (4) with a pore-forming fluid (5) such that the fluid (5) is absorbed into the active material (3); c) heating of the loaded carrier material (4) with the fluid (5) and at least partial expulsion of the fluid (5) from the active material (3) with pore formation.

Description

Technical Field

[0001] This invention relates to a method for manufacturing electrodes for a single battery cell. The active material disposed on a carrier material should, in particular, be mixed with a pore-forming agent. The carrier material particularly includes strip-shaped carrier materials. Background Technology

[0002] Batteries, especially lithium-ion batteries, are increasingly used to drive motor vehicles. Batteries typically consist of individual cells, each of which has a stack of anode, cathode, and separator plates. At least a portion of the anode and cathode plates are designed as current dischargers to divert the current supplied by the individual cell to electrical appliances located outside the individual cell.

[0003] In the manufacture of a lithium-ion battery cell, the carrier material, especially a strip-shaped carrier material such as a carrier film, is coated on both sides with a slurry. The slurry consists of various components, including active materials, conductive carbon black, binders, solvents, and, if necessary, other additives. After coating each side separately, the coated carrier materials are individually conveyed to a drying process to evaporate the contained solvent and firmly bond the remaining components to the carrier film. The carrier film forms the discharge mechanism of the battery cell.

[0004] The resulting coating is porous. Porosity is reduced by calendering, or rolling, because the coating is compacted in this process. Calendering is necessary to improve specific capacitance (based on volume) and conductivity.

[0005] The active material is compressed by approximately 40% during calendering. The calendering process is similar to the rolling process. The active material is compressed with high calendering forces in a small deformation zone. The following problems occur during the calendering process:

[0006] First, due to the high calendering force, the porosity on the surface of the active material is greatly reduced, at which point the electrode contacts the calendering roll. The anode is specifically constructed using graphite as the active material; furthermore, the anode also contains, for example, a binder SBR, a diluent CMS, and conductive carbon. Achieving an active material concentration of 1.6 g / cm³ is particularly sought. 3 A density of [g / cm³] is used to increase the volumetric energy density of a single cell. High density also improves the conductivity of the single cell. The reduced porosity near the surface makes it more difficult for lithium ions to accumulate in the graphite layer. This results in more intense lithium-plating, i.e., the deposition of metallic lithium, on the surface. However, this significantly reduces the lifespan of the single cell. Because deformation during calendering occurs within a very small area (depending on the roller diameter), there is very high stress concentration within this small deformation area, which leads to cracks in the active material. In summary, high compression during calendering is desirable, but it introduces the problem of lithium plating.

[0007] Second, variations in pore structure and deformation of the active material within a defined pore size range are key factors that negatively impact the electrochemical performance of a single battery cell. Surface roughness and the porosity of surface openings certainly affect the overall wetting behavior of the electrode and electrolyte and vary with the compression ratio. Typically, porosity decreases by up to 30% during calendering, but at the surface, deformation of the active material particles can already be observed even with a 20% reduction in compaction (i.e., porosity reduction). This implies that porosity is not uniformly distributed across the layer thickness of the active material. The porosity at the surface is significantly reduced compared to the porosity near the support material.

[0008] The deformation of active material particles is limited to those disposed on the surface of the active material, which affects the electrochemical performance of a single battery cell. The deformation of particles on the surface, achieved through high calendering and compression, leads to obstacles to lithium-ion transport during electrochemical cycling, significantly impacting the long-term performance of these electrodes for relatively high C-rates. With a high porosity reduction of approximately 20% to 26%, particularly large pores with maximum diameters between 2 μm and 5 μm close due to compression. The absence of these large pores on the surface and the overall small total pore volume are a major contributor to lithium plating, significantly reducing the lifespan of a single battery cell.

[0009] Blocking or removing large pores and significantly reducing the total pore volume both result in a reduced amount of electrolyte / active material particle interface material, which can be used for lithium-ion transfer. This reduction in the electrolyte / active material particle interface can lead to electrolyte wetting problems, which in turn degrades electrochemical performance.

[0010] To address the above problems, the following measures have been implemented to date:

[0011] • Add a higher proportion of porous carbon powder (porocarb) with higher porosity; however, porocarb porous carbon powder is an expensive material.

[0012] • The compression ratio during calendering is reduced to less than 20%; however, this reduces the volumetric energy density of a single battery cell and also reduces the conductivity of the active material.

[0013] • Adding 2% to 5% more conductive carbon allows the free space between active material particles to be filled with conductive carbon, achieving conductivity even with low calendering compression.

[0014] However, these measures have the following drawbacks:

[0015] • Less compression during calendering means a lower volumetric energy density per cell;

[0016] • Less compression during calendering means lower conductivity in the active material, because the conductive carbon cannot contact the active material particles;

[0017] More conductive carbon means greater springback after calendering; therefore, anodic calendering must be performed in two steps, with an additional final step used to compensate for the springback; this increases the machine's space requirements and cost.

[0018] • With a higher proportion of conductive carbon, the viscosity of the suspension, or slurry, increases, which means longer drying times and difficulty in wet coating.

[0019] As a viable alternative, the active material can be constructed, for example, into different layers with varying porosities. The top layer has higher porosity to compensate for the reduction in porosity caused by calendering and compaction. However, this makes the coating process very complex. Furthermore, problems arise regarding the cohesion between two adjacent coatings.

[0020] Document CN 111725479 A describes an electrode for a single lithium-ion battery cell and a method for manufacturing the electrode. In this method, the electrode is coated with an active material in which an agent for forming pores has been added.

[0021] The agent that forms pores is added to the active material before the carrier material is coated, thereby affecting at least the chemical properties and viscosity of the active material. Summary of the Invention

[0022] Therefore, the technical problem to be solved by the present invention is to at least partially solve the problems described in the prior art. In particular, a method is proposed by which the porosity of active materials can be advantageously set.

[0023] The above-mentioned problems are solved by a method for manufacturing electrodes for a single battery cell. Advantageous improved designs are the subject of this application. The features described individually in this application can be combined with each other in a technically suitable manner and can be supplemented by details from the description and / or drawings, which indicate further embodiments of the invention.

[0024] A method for manufacturing electrodes for a single battery cell is proposed. The method includes at least the following steps:

[0025] a) Carrier material for preparing electrodes coated with active materials;

[0026] b) Load the carrier material of the coating with a pore-forming fluid, so that the fluid is absorbed into the active material;

[0027] c) Heating of a fluid-loaded carrier material, wherein the fluid is at least partially discharged from the active material in the presence of pores.

[0028] The above (non-closed) division of method steps into a) to c) is primarily for differentiation and does not mandate a specific order or correlation. The frequency of method steps may also vary. It is also permissible for method steps to overlap at least partially in time. Preferably, steps a) to c) are performed in the given order.

[0029] The electrodes to be manufactured are specifically designed for use in single lithium-ion battery cells. The electrodes particularly include a carrier material, such as a copper or aluminum film. The carrier material used is specifically composed of copper with a thickness of 10 to 12 μm for the anode and aluminum with a thickness of 12 to 15 μm for the cathode. The carrier material is coated with an active material at least on its largest side, and if necessary, also on the largest sides opposite each other.

[0030] In particular, active materials include at least one of carbon black, NMC (lithium-nickel-cobalt-manganese active material for lithium storage), graphite (active material for lithium storage), CNT (carbon nanotubes), SBR (styrene-butadiene rubber as a binder), CMC (carboxymethyl cellulose polymer), PVDF (polyvinylidene fluoride), and porous graphite. Components of the material that are not binders are especially considered active materials.

[0031] According to step a), a carrier material coated with an active material is prepared for the electrode. The carrier material for the coating is provided, in particular, as a continuous strip material. The continuous strip material is conveyed, in particular, at least during steps b) and c). In particular, the active material is applied only to the carrier material and, if necessary, leveled, or set in terms of coating thickness, without calendering.

[0032] During calendering, the carrier material for the coating is guided through a roller assembly, which is temperature-controlled and thus heats the carrier material. The coating is compacted by the rollers. Typically, the coating density increases (porosity decreases) by at least 20%.

[0033] According to step b), the carrier material of the coating is loaded with a pore-forming fluid, such that the fluid is absorbed into the active material. The fluid is, in particular, in a liquid state. The fluid penetrates into the porous active material. Specifically, at least 40%, preferably at least 60%, and particularly preferably at least 80% of the total porosity existing prior to step b) is filled or filled by the fluid prior to step c).

[0034] According to step c), in particular, the carrier material loaded with fluid is heated and the fluid is at least partially discharged from the active material in the case of forming pores (first heating stage).

[0035] In particular, the carrier material loaded with fluid is heated to at least one boiling temperature of the fluid so that the fluid is discharged from the active material while forming pores.

[0036] Especially between steps b) and c), in another step x), the active material is compacted, particularly at least 15%, preferably at least 20%, and particularly preferably at least 22%. Especially at most 35%, preferably at most 30%.

[0037] In particular, the active material is compacted to at least 1.5 g / cm³ in step x). 3 The density is preferably at least 1.6 g / cm³. 3 .

[0038] In particular, step x) includes calendering, and step c) is spatially spaced from step x). Calendering is performed without a heating device, meaning there is no targeted increase in the temperature of the active material. The fluid absorbed by the active material further supports the pores of the active material, ensuring that the compaction of the active material is uniform in layer thickness. Over-compaction, especially on the surface of the coating, is prevented. Calendering, or compaction, is performed primarily at room temperature.

[0039] Rollers used in calendering can be excited, in particular, by ultrasonic excitation devices. This allows fluid to be transferred into the pores of the coating on the carrier material.

[0040] In particular, step c) is carried out solely by thermal convection or thermal radiation, i.e., especially without thermal conduction. Specifically, the active material does not come into contact with the heated rollers or (calendering) rolls. Specifically, a radiant heater or hot airflow is provided, through which heat is transferred to the active material.

[0041] In particular, the carrier material of the coating is processed as a continuous material at least during steps a) to c), and after step c), it is divided into electrode sheets, for example in step d).

[0042] In particular, step b) is carried out in an immersion tank filled with fluid, through which the carrier material for the coating is transported.

[0043] The immersion tank is particularly well-arranged within the shell. The pressure within the immersion tank is particularly high compared to the external pressure present outside the shell. A double shell is particularly well-designed to prevent ambient air from entering the inner shell or the immersion tank. The outer shell, made of approximately 10 mm thick steel plate, can also be designed as a shroud to protect against liquid leakage or explosion. The inner shell is particularly well-constructed of stainless steel plate for corrosion resistance. The inner shell is particularly well-constructed of approximately 5 mm thick refined steel plate.

[0044] Alternatively or additionally, the fluid is sprayed onto the active material in step b).

[0045] In particular, the carrier material of the coating is guided in step b) by a series of rollers (hereinafter referred to as pressure rollers), which are located, for example, in an immersion tank or after various spray devices if necessary, so that the surface of the active material can have maximum contact with the fluid. In particular, mechanical pressure is applied to the surface of the active material by the pressure rollers, causing the fluid to penetrate into the active material and at least partially fill the pores.

[0046] In particular, the carrier material for the coating, within the scope of step b), is guided by a series of rollers (hereinafter referred to as coating rollers), which are fluid-loaded. Here, the carrier material for the coating is fluid-loaded primarily by rollers and is not conveyed through the fluid. The coating rollers may, for example, be partially arranged in an immersion tank or fluid-loaded via a spray device.

[0047] When the carrier material of the coating is compressed to its final thickness during compaction or calendering, some fluid is forced outward from the pores, as the fluid is, in particular, an incompressible medium. To prevent fluid extrusion, a carrier film, for example made of polyurethane, can be arranged on the upper and lower layers of the carrier material of the coating. The carrier film, in particular, prevents direct contact between the carrier material of the coating and the compaction rollers or calender rolls. The carrier film transmits the compressive or calendering force to the carrier material of the coating. The carrier film is particularly used as a sealing material to prevent fluid from being squeezed outward from the pores. After compaction or calendering, the carrier film can be removed from the carrier material of the coating and, if necessary, rolled up.

[0048] The coating roller can in particular have a structured surface, such as recessed areas, for example, with a depth of up to 20 μm and a maximum width of 1 to 10 mm. This can improve the transfer of fluid into the pores of the coating's carrier material.

[0049] In particular, the fluid has a boiling temperature or boiling point of up to 105 degrees Celsius in the environmental conditions of step d), for example, at an ambient pressure of about 1 bar, preferably below 100 degrees Celsius, and especially preferably below 95 degrees Celsius.

[0050] In particular, the fluid that forms the pores contains at least one of the following components, or is made solely from that component, or contains only one or more of the following components:

[0051] • Ethers, such as tetrahydrofuran (THF); boiling point approximately 66 degrees Celsius;

[0052] • Dichloromethane; boiling point approximately 39 degrees Celsius;

[0053] • Light naphtha; consisting of molecules with at least 5 to 6 carbon atoms; boiling point between 30 and 90 degrees Celsius;

[0054] • Alcohols, such as methanol (boiling point about 65 degrees Celsius), ethanol (boiling point about 78 degrees Celsius), or 1-propanol (boiling point about 97 degrees Celsius);

[0055] Aldehydes, such as propionaldehyde (boiling temperature about 46 degrees Celsius), butyraldehyde (boiling temperature about 75 degrees Celsius), or pentanaldehyde (boiling temperature about 102 degrees Celsius).

[0056] · Ketones, such as 2-propanone (boiling temperature about 56 degrees Celsius), 2-butanone (boiling temperature about 80 degrees Celsius), or 2-pentanone (boiling temperature about 103 degrees Celsius);

[0057] • Dimethyl carbonate (DMC - boiling point approximately 90 degrees Celsius).

[0058] In particular, the fluid contains only the components of the electrolyte that are also used in the battery cell, so that the remaining amount of fluid in the active material is harmless to the operation of the battery cell.

[0059] Preferably, a liquid that does not dissolve the binder in the active material is used, and the liquid is non-toxic and non-flammable. Tetrahydrofuran (THF) or dimethyl carbonate is particularly suitable in these respects.

[0060] Specifically, the carrier material of the coating can undergo a skin-drawing process before step b) to set the thickness of the electrode or active material coating. During skin-drawing, both sides of the coating or the carrier material of the coating are compressed, whereas strip drawing (flattening / smoothing) only processes one side of the coating. However, the compression during skin-drawing is a maximum of 10%.

[0061] In particular, following step c), the carrier material of the coating is cut in a further step d). Cutting includes, for example, dividing the continuous material into individual electrode sheets and / or slitting and / or dividing the continuous material into multiple strips of material with smaller widths (so-called slits).

[0062] During the incision, a (uncoated) collector or discharger is formed on the carrier material.

[0063] Cutting is accomplished, especially through mechanical slitting or punching, and by laser, water jet or ultrasonic cutting.

[0064] Especially in the context of step b) and after fluid loading, and particularly before step x), the carrier material of the coating is guided by rollers (hereinafter referred to as pressure rollers) to facilitate fluid penetration into the pores of the active material. The carrier material of the coating wetted with a fluid having a low boiling temperature is preferably wiped off with a (titanium) pressure roller, allowing the fluid to penetrate deeper into the pores.

[0065] The carrier material of the coating is then (immediately) guided back through rollers or trolleys (hereinafter referred to as cleaning rollers) to remove excess fluid from the surface of the active material. The cleaning rollers are particularly designed with a rubber surface. This ensures that the fluid remains in the pores of the active material, but excess fluid present on the surface of the active material is removed.

[0066] Preferably, the cleaning roller can be vibrated to better remove excess fluid from the surface of the active material.

[0067] Since the fluid used to load the coating carrier material according to step b) can act as a lubricant, it is specifically stipulated that the coating carrier material is squeezed into a (calendering) roll provided for compacting the active material. For this purpose, between steps b) and x), the coating carrier material is guided by rollers or trolleys, hereinafter referred to as friction rollers. Friction rollers have a high coefficient of friction, particularly on the surface in contact with the coating carrier material, through which the coating carrier material can be moved towards and through the (calendering) roll.

[0068] In particular, step c) is performed (immediately) after step x), wherein the compacted, coated carrier material is heated and dried by discharging fluid from the active material. The heating of the active material is particularly carried out by a heat source, such as an infrared heater or a fan. In the case of a carrier material coated on one side, the active material is heated, in particular, by the uncoated side of the carrier material, i.e., indirect heating.

[0069] The active materials are heated to temperatures of up to 100 to 110 degrees Celsius to prevent damage. The binders in the active material coating can typically withstand temperatures up to 120 degrees Celsius before softening and melting.

[0070] In particular, the active material is heated to at least the highest boiling temperature of the identified components in the fluid.

[0071] Due to the heating of the active material, the fluid accumulated within it evaporates. Bubbles escape from the particularly compacted coating of the active material. These bubbles create new pores within the active material, and existing pores expand. These pores are then used by lithium ions for intercalation during the operation of the battery cell after the initial cell cycle. Lithium ions can thus easily penetrate the active material because the surface of the active material has sufficient porosity due to the bubble evacuation process. This also greatly reduces lithium deposition, i.e., the deposition of metallic lithium (lithium plating).

[0072] In particular, step c) specifies that the gaseous fluid is drawn away and reused in step b) if necessary. A suction device can be provided for this purpose.

[0073] Heating of the carrier material of the active material or coating is particularly carried out in a (direct current or through-flow) chamber through which the carrier material of the coating is transported.

[0074] Especially after step c), the carrier material of the coating is cooled, for example by guiding the carrier material of the coating through rollers, hereinafter referred to as cooling rollers. Cooling is carried out at a temperature of up to 40 degrees Celsius.

[0075] Especially after step c) or after cooling, inspect the surface using a measuring device (optical if necessary). Check the surface of the active material for any potential damage.

[0076] Furthermore, after step c), the thickness of the coating's carrier material is checked, especially using a measuring device (optical or tactile, if necessary). If necessary, the thickness can be corrected by altering step x).

[0077] In particular, according to step d), the carrier material of the coating is rolled up or transported directly for further processing.

[0078] Especially before or after step d), the carrier material of the coating is heated in an oven for two (2) to 15 hours, especially to a temperature of 100 to 110 degrees Celsius (second heating stage). In particular, any fluid residue, including water particles if present, is also removed from the pores of the active material.

[0079] The problem of closing or reducing pores is even greater when the electrode is set as the anode, especially when the rolling compression is high or the compaction is strong. However, the suggested method can also be used to set the electrode as the cathode.

[0080] The proposed method has the following advantages:

[0081] • Due to compaction (step x), pore closure does not result in lithium plating here;

[0082] • After compaction (step x), the pore volume increases as fluid is expelled from the active material;

[0083] Fluid absorption in the active material coating can be controlled by mechanical pressure;

[0084] • The fluid forms a lubricating film on the surface of the active material, thereby reducing friction between the roller and the carrier material of the coating; thus reducing the stretching of the active material in the transport direction; thereby reducing folding in the carrier material and also reducing problems such as crack elongation on the surface of the active material.

[0085] • Fluid seeps into the pores and generates back pressure during compaction according to step x); therefore, the pores are not easily closed; the pores decrease during compaction, but are in particular not less than 2 micrometers; this means that not only does the porosity increase through the release of the fluid, but there are also useful pore sizes greater than 2 micrometers.

[0086] • Achieve high volumetric energy density in electrodes without reducing pore volume;

[0087] • The conductivity of the active material is increased by the high density achieved after compaction;

[0088] Most of the recommended organic fluids are mixable with water; this means that all water particles remaining in the pores are mixed with the fluid and evaporate and are expelled from the pores with the fluid during the first and second heating stages; in this way, the water content in the electrodes can be greatly reduced, which has a positive impact on the performance of the battery cell.

[0089] Furthermore, a single battery cell is proposed, comprising at least a single battery cell housing and at least one electrode disposed therein, the electrode being manufactured by the method described above.

[0090] A single battery cell specifically includes a single battery cell housing that surrounds a volume, a first electrode membrane of at least one first electrode type disposed in the volume, a second electrode membrane of a second electrode type, a separating material disposed therebetween, and a liquid electrolyte.

[0091] Battery single cells, particularly pouch-type single cells (having a deformable battery single cell housing composed of a pouch-shaped membrane) or prismatic single cells (having a shape-stable battery single cell housing). The pouch-shaped membrane is a known deformable housing component, which is used as the battery single cell housing of the so-called pouch-type single cell. It is here made of composite materials, such as plastics and aluminum.

[0092] Single battery cell, especially lithium-ion single battery cell.

[0093] Multiple electrodes, designed as electrode films, are stacked and, in particular, form a stack. The electrode films are assigned to different electrode types, i.e., they are designed as anodes or cathodes. Here, anodes and cathodes are arranged alternately and separated from each other by a separating material.

[0094] A battery cell is a current storage device, used, for example, in motor vehicles to store electrical energy. In particular, motor vehicles have, for example, an electric motor (traction drive) that drives the vehicle, wherein the motor can be powered by the electrical energy stored in the battery cell.

[0095] Furthermore, a motor vehicle is proposed, comprising at least a traction drive and a battery having at least one of the battery cells, wherein the traction drive can be powered by at least one battery cell.

[0096] In particular, at least one system for data processing is provided, the system having means that are appropriately equipped, configured or programmed to implement the method, or the means implement the method.

[0097] The means, for example, includes a processor and a memory, in which commands to be executed by the processor are stored. The means also includes a data line or transmission device that enables the transmission of commands, measurements, data, or the like between the aforementioned elements, such as a drive device, a driven roller, a spray device, a suction device, etc.

[0098] Furthermore, a computer program is proposed that includes commands that, when executed by a computer, cause the computer to perform the method or the steps of the method.

[0099] Furthermore, a computer-readable storage medium is proposed, comprising a command that, when executed by a computer, causes the computer to perform the method or the steps of the method.

[0100] The design of the method can be transferred in particular to battery cells, motor vehicles, systems for data processing, and / or computer-implemented methods (i.e., computer programs and computer-readable storage media), and vice versa.

[0101] The use of the indefinite article "a" is not understood as a quantifier, especially in the claims and the description interpreting the claims. Accordingly, the relevant terms and components are understood to exist at least once, but in particular, they may exist multiple times.

[0102] It should be noted that the ordinal numbers used herein (“first,” “second,” etc.) are primarily (only) used to distinguish multiple objects, quantities, or processes of the same kind; that is, they do not, in particular, mandate the relationship and / or order between these objects, quantities, or processes. If a relationship and / or order is required, it will be explicitly stated herein or will be obvious to those skilled in the art when studying the specifically described design. As long as a component can appear multiple times (at least one), the description of one such component also applies to all or most of that component, but this is not necessarily the case. Attached Figure Description

[0103] The invention and its technical field are further described below with reference to the accompanying drawings. It should be noted that the invention is not limited to the embodiments described. In particular, unless otherwise explicitly stated, certain aspects can be extracted from the facts illustrated in the figures and combined with other components and knowledge derived from this description. It should be particularly noted that the drawings and the dimensional relationships shown are merely schematic. Wherein:

[0104] Figure 1 : A cross-sectional side view of a first embodiment of the immersion tank is shown;

[0105] Figure 2 : A cross-sectional side view of a second embodiment of the immersion tank is shown;

[0106] Figure 3 : A sectional side view of the spraying device;

[0107] Figure 4 The method described in step b) is shown in the sectional side view after the step b).

[0108] Figure 5 A third implementation scheme for step b) of the method;

[0109] Figure 6 A fourth implementation scheme for step b) of the method;

[0110] Figure 7 : A fifth implementation scheme for step b) of the method. Detailed Implementation

[0111] Figure 1 A cross-sectional side view of a first embodiment of the immersion tank 8 is shown.

[0112] According to step a), the carrier material 4 coated with active material 3 is prepared specifically for electrode 1. The coated carrier material 4 is provided as a strip-shaped continuous material 6. The strip-shaped continuous material 6 is conveyed along the conveying direction 14 at least during steps b) and c). The active material 3 is only coated or applied to the carrier material 4 and is leveled or the coating thickness is adjusted if necessary, but it is not calendered.

[0113] According to step b), the carrier material 4 of the coating is loaded with a porous fluid 5, such that the fluid 5 is absorbed into the active material 4. The fluid 5 is in a liquid state. The fluid 5 penetrates into the porous active material 3.

[0114] Step b) is carried out in an immersion tank 8 filled with fluid 5, through which the carrier material 4 of the coating is conveyed.

[0115] The immersion tank 8 is arranged within the housing 12. The pressure in the immersion tank 8 is higher than the external pressure present outside the housing 12. A double-shell structure is provided to prevent ambient air from entering the inner housing 12 or the immersion tank 8. Gas 11, such as nitrogen, is introduced into the housing 8 through inlet 13. The immersion tank 8 and fluid 5 are thus isolated from the environment by gas 11. The housing 8 is sealed by a sealing device 10.

[0116] In step b), the carrier material 4 of the coating is guided by a series of guide rollers 9 located in the immersion tank 8 so that the carrier material 4 is conveyed through the fluid 5 and the surface of the active material 4 can have maximum contact with the fluid 5. Mechanical pressure is also applied to the surface of the active material 4 by the guide rollers 9, causing the fluid 5 to penetrate into the active material 4 and at least partially fill the pores.

[0117] Figure 2 A cross-sectional side view of a second embodiment of the immersion tank 8 is shown. (Reference to...) Figure 1 Explanation.

[0118] In this context Figure 1 As shown differently, the carrier material 4 of the coating is unrolled from the roll and fed into the immersion tank 8. The roll is driven by the drive unit 16, causing the carrier material 4 of the coating to be conveyed along the conveying direction 14. The carrier material 4 of the coating, which is conveyed as continuous material 6, is tensioned by the tension roller 17.

[0119] In step b), the carrier material 4 of the coating is guided by a plurality of directional rollers 9 located in the immersion tank 8 so that the carrier material 4 is conveyed through the fluid 5 and the surface of the active material 4 can have maximum contact with the fluid 5.

[0120] Within the scope of step b) and while still being loaded with fluid 5 and prior to step x), the carrier material 4 of the coating is guided by the pressure roller 18, thereby allowing the pressure roller-assisted fluid 5 to penetrate into the pores of the active material 3.

[0121] The carrier material 4 of the coating is then and immediately after step b) guided by the cleaning roller 20 to remove excess fluid 5 from the surface of the active material 4.

[0122] Since the fluid 5 used to load the coating carrier material in step b) can act as a lubricant, it is stipulated that the coating carrier material 4 is squeezed into the (calendering) roller 21, which is designed to compact the active material 3. For this purpose, the coating carrier material 4 is guided by the friction roller 19 between steps b) and x). The friction roller 19 has a high coefficient of friction on the surface in contact with the coating carrier material 4, and the coating carrier material 4 can be moved towards and through the (calendering) roller 21 via the friction roller 19.

[0123] Figure 3 A sectional side view of the spray device 15 is shown. (Reference to...) Figure 1 Explanation.

[0124] Compared to Figure 1 The difference is that there is no immersion tank 8 here, but the carrier material 4 of the coating is loaded with fluid 5 through multiple spray devices 15.

[0125] Figure 4 The diagram shows a sectional side view after step b) of the method described above. References to... Figure 2 Explanation.

[0126] In particular, the calendering roll 21 shown here is arranged directly after the friction roll 19.

[0127] Between steps b) and c), in another step x), the active material 3 is compacted or calendered. Step x) involves calendering with calendering rolls 21. Calendering is performed without a heating device, meaning no targeted increase in temperature is applied to the active material 3. The fluid 5 absorbed in the active material 3 further supports the pores of the active material 3, ensuring that the compaction of the active material 3 is uniformly across the overall layer thickness. This prevents over-compaction on the surface of the coating. Calendering or compaction is performed at room temperature.

[0128] According to step c), the carrier material 4 loaded with fluid 5 is heated and the fluid 5 is at least partially discharged from the active material 3 in the case of forming pores (first heating stage).

[0129] The carrier material 4 loaded with fluid 5 is heated to at least one boiling temperature of fluid 5 so that fluid 5 is discharged from active material 3 while forming pores.

[0130] Step c) is carried out solely by thermal convection or thermal radiation, i.e., especially without thermal conduction. The active material 3 does not come into contact with the heated rollers or (calendering) rolls. In particular, a radiant heater or hot airflow is provided, through which heat is transferred to the active material.

[0131] Heating of the active material 3 is achieved via a heat source 24, such as an infrared heater or a fan. In the case of a carrier material 4 coated on one side, the active material 3 is heated via the uncoated side of the carrier material 4, i.e., indirect heating.

[0132] The carrier material 4 of the coating is processed as a continuous material 6 at least during steps a) to c), and after step c), it is divided into electrode sheets or electrodes 1, for example in step d).

[0133] Following step c), in a further step d), the carrier material 4 of the coating is cut in the cutting device 27. Cutting includes, for example, dividing the continuous material 26 into individual electrode sheets 7 or electrodes 1 and / or slicing and / or dividing the continuous material 26 into multiple strips of material with smaller widths (so-called slits). The electrodes 1 can be arranged in a stack and used in a single battery cell 2.

[0134] When cut, a (uncoated) current collector or discharger is formed on the carrier material 4.

[0135] Due to the heating of the active material 3, the fluid 5 accumulated in the active material 3 evaporates. Bubbles are expelled from the particularly compacted active material coating. Due to the bubbles, new pores are formed in the active material 3 and existing pores are enlarged.

[0136] Step c) specifies that the gaseous fluid 5 is drawn away and reused in step b) if necessary. A suction device 22 can be provided for this purpose.

[0137] Heating of the active material 3 or the carrier material 4 of the coating is carried out in the (direct current or through) chamber 23, through which the carrier material 4 of the coating is transported.

[0138] After step c), the carrier material 4 of the coating is cooled by guiding the carrier material 4 of the coating on the cooling roller 25. Cooling is carried out at a temperature of up to 40 degrees Celsius.

[0139] After step c) and even after cooling, the surface is inspected using a (optical) measuring device 26. This inspection checks the surface of the active material 3 for any potential damage.

[0140] Furthermore, after step c), the thickness of the carrier material 4 of the coating is checked using a measuring device 26 (if necessary, optical or tactile). If necessary, the thickness can be corrected by changing step x).

[0141] According to step d), the carrier material 4 of the coating is transported for further processing.

[0142] Figure 5 A third embodiment of step b) of the method is shown. References to Figure 2 Explanation.

[0143] Unlike Figure 2 As shown here, the carrier material 4 of the coating is guided by the coating roller 28 loaded with fluid 5 within the scope of step b). Here, the carrier material 4 of the coating is loaded with fluid 5 only by the coating roller 28 and is not transported by fluid 5 itself. The coating roller 28 may be partially arranged in the immersion tank 8, for example, or the fluid 5 may be loaded by a spray device 15 or a transfer device 29, such as a sponge.

[0144] The carrier material 4 of the coating is guided by multiple steering rollers 9 in the scope of step b) so that the carrier material 4 is conveyed through the coating roller 28 and the surface of the active material 3 can come into contact with the fluid 5.

[0145] Within the scope of step b) and while still being loaded with fluid 5 and prior to step x), the carrier material 4 of the coating is guided by the pressure roller 18 so that its auxiliary fluid 5 penetrates into the pores of the active material 3.

[0146] The carrier material 4 of the coating is then guided by the cleaning roller 20 immediately after step b) to remove excess fluid 5 from the surface of the active material 3.

[0147] Figure 6 A fourth embodiment of step b) of the method is shown. References to Figure 3 Explanation.

[0148] Unlike Figure 3 Here, the coating roller 28 is loaded with fluid 5 by the spray device 15. The spray device 15 transfers the fluid 5 to the transfer device 29, which is the sponge, and then contacts the coating roller 28.

[0149] Figure 7 A fifth embodiment of step b) of the method is shown. References to Figure 5 Explanation.

[0150] Unlike Figure 5 As shown here, the carrier material 4 of the coating is guided by the coating roller 28 loaded with fluid 5 in the scope of step b). Here, the carrier material 4 of the coating is only loaded with fluid 5 by the coating roller 28 and is not transported by fluid 5 itself. The coating roller 28 is also loaded with fluid 5 by a belt-like transport device 29. The transport device 29 is guided by a steering roller 9 and here by the immersion tank 8. Fluid 5 is absorbed by the transport device 29 and transported towards the coating roller 28. The coating roller 28 can be designed as a calendering roller 21 so that the active material 3 can be compacted here.

[0151] List of reference numerals in the attached diagram:

[0152] 1 Electrode

[0153] 2 single-cell battery

[0154] 3. Active materials

[0155] 4. Carrier Material

[0156] 5. Fluid

[0157] 6. Continuous materials

[0158] 7 Electrode plates

[0159] 8 Immersion tank

[0160] 9. Steering rollers

[0161] 10 Sealing device

[0162] 11 Gases

[0163] 12. Shell

[0164] 13 Entrances

[0165] 14 Conveying device

[0166] 15. Spraying device

[0167] 16. Drive unit

[0168] 17 tension rollers

[0169] 18 pressure rollers

[0170] 19 Friction Rollers

[0171] 20 Cleaning Rollers

[0172] 21 Calendering Rolls

[0173] 22 Suction Device

[0174] 23 chambers

[0175] 24 Heat source

[0176] 25 Cooling rollers

[0177] 26 Measuring device

[0178] 27 Cutting device

[0179] 28 Coating Rollers

[0180] 29 Transmission Devices

Claims

1. A method for manufacturing an electrode (1) for a single battery cell (2); wherein, The method comprises at least the following steps: a) The carrier material (4) coated with the active material (3) for preparing the electrode (1); b) The carrier material (4) of the coating is loaded with a pore-forming fluid (5) such that the fluid (5) is absorbed into the active material (3), wherein the fluid (5) is in a liquid state; c) The carrier material (4) is loaded with a heating fluid (5), and the fluid (5) is at least partially discharged from the active material (3) in the case of forming pores. Between steps b) and c), the active material (3) is compacted in an additional step x), wherein step x) includes calendering.

2. The method according to claim 1, wherein, The active material (3) is compacted to a density of at least 1.5 g / cm³ in step x).

3. The method according to claim 1, wherein, Step c) is performed spatially at intervals from step x).

4. The method according to claim 1, wherein, Step c) is carried out solely by thermal convection or thermal radiation.

5. The method according to claim 1, wherein, The carrier material (4) of the coating is processed as a continuous material (6) at least during steps a) to c), and is separated into electrode sheets (7) after step c).

6. The method according to claim 1, wherein, Step b) is carried out in an immersion tank (8) filled with fluid (5), through which the carrier material (4) of the coating is transported.

7. The method according to claim 1, wherein, The fluid (5) is sprayed onto the active material (3) in step b), or coated onto the active material (3) by a coating roller (28).

8. The method according to claim 1, wherein, Under the environmental conditions of step d) following step c), fluid (5) has a maximum boiling temperature of 105 degrees Celsius.

9. The method according to claim 1, wherein, The fluid (5) that forms the pores contains at least one of the following components: •ether; • Dichloromethane; • Light naphtha, said light naphtha comprising at least a molecule having 5 to 6 carbon atoms; •alcohol; •aldehyde; •ketone; • Dimethyl carbonate.

10. The method according to claim 9, wherein, The fluid (5) includes tetrahydrofuran (THF).

11. The method according to claim 9, wherein, The fluid (5) includes methanol, ethanol or 1-propanol.

12. The method according to claim 9, wherein, The fluid (5) includes propionaldehyde, butyraldehyde, or pentanaldehyde.

13. The method according to claim 9, wherein, The fluid (5) includes 2-propanone, 2-butanone or 2-pentanone.

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