Method for preparing and modulating electrode mixture and method for manufacturing dry electrode from electrode mixture

Abstract

The invention relates to a method for preparing and modulating an electrode mixture and a method for manufacturing a dry electrode from an electrode mixture. The invention relates to a method for producing and preparing an electrode mixture consisting of an active material, optionally an additive and a binder, comprising the following steps: 1) producing the electrode mixture in a mixing vessel, the mixture being heated to a temperature TH, where THgt; 2) cooling the electrode mixture in the mixing vessel at least [Delta] T = 5 DEG C, preferably to a temperature TMAXlt; 35 DEG C, but not lower than the take-out temperature TEgt; 3) removing the electrode mixture having a removal temperature and supplying the electrode mixture to a cooling device, 4) cooling the electrode mixture after step 2) by means of the cooling device at least 4 DEG C, preferably to a temperature TKlt; and 19 DEG C.

Description

[0001] This invention relates to methods for preparing and modulating dry electrode mixtures. It also relates to methods for manufacturing dry electrodes from these electrode mixtures.

[0002] In recent years, battery technology, especially lithium-ion technology, has gradually become a focus of attention because it is crucial for the functionality of vehicles such as all-electric vehicles, as well as for stationary energy storage devices. The low manufacturing cost of large-capacity, durable batteries is a prerequisite for the acceptance of all-electric vehicles.

[0003] Currently, lithium-ion batteries are the primary type used. Within this category, several specific battery chemistry types dominate, with the most widely used cathode materials being as follows:

[0004] - Nickel-manganese-cobalt (NMC) electrode mixture: These batteries use a mixture of nickel, manganese, and cobalt. Nickel provides high energy density, manganese provides thermal stability, and cobalt is responsible for structural stability.

[0005] - Nickel-Cobalt-Aluminum (NCA) Electrode Mixture: This mixture contains nickel, cobalt, and aluminum in the cathode. The aluminum content stabilizes the structure and increases service life, while nickel maximizes energy density.

[0006] - Lithium iron phosphate (LFP) electrode mixture: In this cobalt-free battery chemistry, lithium iron phosphate is used as the cathode material, which has a lower energy density but provides a longer lifespan and better thermal stability.

[0007] The anode is typically made of graphite or a silicon-graphite mixture. In all these types, the electrode mixture is prepared using a polymer binder (sometimes with conductive additives), applied to a discharge foil, and calendered during or after the process to optimize the structural integrity and density of the electrode.

[0008] In addition, there are several developments that may play a relevant role in the future. Besides the lower-cost but lower-performance and cobalt-free sodium-ion battery chemistry, there is active research and development on all-solid-state batteries with solid-state electrolytes. Theoretically, this technology offers higher energy density than conventional lithium-ion batteries, and because the electrolyte is solid-state, it provides greater safety. The manufacture of all these batteries is expected to continue to require rolled electrodes, which will present various challenges to the rolling process.

[0009] In summary, the calendering of electrode mixtures will also play an important role in future battery technology, as calendering optimizes the density, uniformity, and mechanical properties of the electrodes. However, the specific materials used will depend on advancements in materials science and the requirements of electric vehicles.

[0010] A typical lithium-ion battery electrode has a copper foil used as the anode and an aluminum foil used as the cathode. These foils are typically coated with active materials on both sides, and at least for the purpose of manufacturing the cathode, they are also coated with additives.

[0011] High requirements are placed on the electrodes in order to manufacture reliable, high-capacity lithium-ion batteries.

[0012] The electrode layer needs to have a defined, constant thickness and a defined pore structure into which the electrolyte can enter, enabling the delivery of lithium ions to each particle of the active material. Ideally, the active material needs to be wetted with the electrolyte over the largest possible area. Furthermore, the active material particles need to be electrically connected to a metal foil (i.e., in this example, copper or aluminum foil) to ensure that electrons are delivered to and from each active material particle.

[0013] Furthermore, the active material particles need to bond together with each other and onto the metal foil, for which an adhesive material is used. Finally, the layer thickness should be formed as uniformly as possible in both width and length.

[0014] To manufacture these layers, the raw materials (i.e., active materials, binders, and optional additives) need to be mixed and dispersed into a so-called "slurry" (paste, suspension). Typically, a liquid solvent (e.g., water or N-methyl-2-pyrrolidone (NMP)) is added here, which needs to be removed again through a complex drying process after the electrode mixture is applied to the foil. The cavities created during the drying process are compressed into a defined porosity during the subsequent calendering process.

[0015] Mainstream wet electrode processing is both time-consuming and energy-intensive. In addition, the mechanical production of electrode mixtures often requires large-scale drying equipment.

[0016] There are also dry methods for preparing electrode mixtures, using very little or no solvent. However, in this case, more intensive processing is required when mixing the components to transform the polymer binder, which is no longer soluble in the solvent, into a processable and bondable state. Especially when using PTFE or PVDF as the binder, the mixture typically needs to be processed in successive steps at different temperatures. When using PTFE, the mixture undergoes fibrillieren at temperatures >30°C through temperature activation and the introduction of shear energy. The nano- and micron-sized polymer fibers generated during fibrillieren produce a material that transitions from a granular to a plastic state, which is difficult to remove from the mixer. Furthermore, since the mixture needs to be uniformly metered into the calender gap to produce the desired electrode film, this granular-to-plastic state is generally not used. The material needs to first be converted into easily metered clumps, particles, or powder.

[0017] Therefore, based on the described prior art, the object of the present invention is to provide a method for preparing dry electrode mixtures, which provides high-quality electrode mixtures that are easy to process.

[0018] This objective is achieved by a method for preparing and modulating an electrode mixture comprising an active material, optional additives, and a binder, the method comprising the following steps:

[0019] 1) An electrode mixture is prepared in a mixing vessel, wherein the mixture is heated to temperature T during preparation. H T H >45℃,

[0020] 2) Cool the electrode mixture in the mixing container to at least ΔT = 5°C, preferably to temperature T. MAX <35℃, but not lower than the removal temperature T E >24℃,

[0021] 3) Remove the electrode mixture at the removal temperature and supply the electrode mixture to the cooling device.

[0022] 4) Using a cooling device, cool the electrode mixture after step 2) by at least 4°C, preferably to temperature T. K <19℃.

[0023] It has been demonstrated that significantly increasing the temperature of the electrode mixture during the mixing process, i.e., raising it to above 45°C, can significantly improve the quality of the electrode mixture. This can be achieved, for example, by introducing high mechanical power through frictional heat using a stirrer. However, in the resulting plastic, elastic, and "viscous" state, the electrode mixture is difficult to remove from the mixing container. Furthermore, the consistency of the electrode mixture does not allow for uniform metering distribution into the calender gap.

[0024] If the optimally mixed electrode mixture is cooled while in motion (e.g., by a stirring or mixing tool), it can achieve greater processability. Here, the plastic, cohesive material is broken down into metered, dispenseable bulk materials. However, this is very time-consuming because the mixing vessel needs to be cooled by its walls, and heat dissipation is limited by the cooled surfaces of the vessel walls. Furthermore, the heat stored in the mixing vessel itself needs to be removed, which slows down the cooling of the product. Additionally, if processing is performed in the mixing vessel, it needs to be reheated after removal because the subsequent preparation of the next batch requires high temperatures.

[0025] According to the invention, the electrode mixture is now prepared in multiple steps. After heating the mixture (during which the binder and / or solid electrolyte added together with the other mixture components are converted to a non-segregation state), in the next step, the mixture in the mixing vessel is cooled to at least ΔT = 5°C, preferably to temperature T. MAX <35℃, but not lower than the removal temperature T E >24℃. This slow-moving cooling process transforms the mixture into a bulk material. Therefore, the electrode mixture can be more easily removed from the mixing container. Depending on the raw material formulation, the electrode mixture may not yet possess complete storage stability, allowing for smooth discharge from buffer containers or silos. Furthermore, due to the presence of excessively large particles, the electrode mixture is not entirely suitable for high-precision feeding into the tens of micrometers wide gap of a calender.

[0026] For example, ethylene carbonate (EC) is used as a material in all-solid-state batteries (ASSB). EC is used as a solid electrolyte. By heating to above 45°C, EC, which is solid at room temperature, becomes liquid, and can therefore be formed into clumps or granules with other powdered raw materials. By cooling to below 35°C in step 2), the granules are solidified, and can therefore be easily removed from the mixing container. In principle, the preparation of such molten granules can also be carried out using other fusible binders, electrolytes, or additives.

[0027] To ensure the electrode mixture has storage stability while facilitating metering and dispensing, the electrode mixture is removed from the mixing container and supplied to a cooling device. Therefore, the electrode mixture is only slightly cooled within the mixing container and removed while still warm. This has the advantage of reducing the need for excessive cooling of the mixing container and excessive heating for subsequent batches, thus reducing energy consumption and cycle time.

[0028] Then, with the aid of a cooling device, the removed electrode mixture is cooled to at least 4°C, preferably to temperature T. K <19°C. This will make the electrode mixture more stable in terms of storage, transportation, and metering, especially when using PTFE as a binder. Ideally, the PTFE contained in the mixture is first cooled to a temperature <35°C (still in the state of pseudo-hexagonal PTFE in an extremely disordered phase), where the mixture decomposes, and then the mixture can be more easily transported from the mixing container. Since the crystal structure changes over two temperature ranges, the fibrillation tendency of PTFE decreases with decreasing temperature. Here, cooling is preferably carried out below the phase transition temperature of 30°C when PTFE enters the partially ordered hexagonal phase, or better yet, below 19°C when it enters the well-ordered triclinic phase.

[0029] Fundamentally, the cooling of the electrode mixture is carried out in two steps. In the first step, cooling proceeds only to the point where the electrode mixture can be easily removed from the mixer by being transformed into a structured bulk material state. Then, further cooling occurs outside the mixing vessel, necessary to bring the electrode mixture to a state that is as storage-stable and easily metered as possible, allowing for further processing in the calender. Since the mixing vessel no longer requires extensive cooling, cycle time can be significantly reduced.

[0030] For example, the cooling device may include a second mixer arranged in a cascade configuration, the walls of which are cooled. However, this increases the number of machines, thus leading to increased costs from the outset. But overall, fewer machines and lower operating costs can be achieved due to the significantly reduced residence time in the heating and cooling mixers at high production volumes. Furthermore, if the second mixer is arranged in a suitable manner such that the mixture can be transferred directly from the main mixer used to prepare the mixture into the second mixer (e.g., by gravity), step 2 can even be performed in the second mixer.

[0031] In a preferred embodiment, the delivery line of the pneumatic conveying device for removing the electrode mixture from the mixing container of the mixer is configured as the cooling device in steps 3) and 4), and this delivery line preferably has a temperature T. G The gas is operated at <19°C, wherein preferably in step 2), between steps 2) and 3) and / or during step 3), dry ice or liquid gas (e.g., liquid nitrogen) is introduced into the mixing container, wherein the gas generated by sublimation or evaporation is directed into the delivery line.

[0032] The pneumatic conveying device used to remove the electrode mixture from the mixing container ensures that the mixture can be removed effectively and cleanly without segregation or significant alteration of the bulk properties of the particles or damage to the particles.

[0033] In addition, pneumatic conveying devices include pneumatic conveying units, which typically include a blower or compressor to generate the required airflow, as well as a feeding device, conveying lines and a material separator, which may also be equipped with double jackets for cooling and / or insulation.

[0034] The feeding device is installed in the mixing container (e.g., in the form of a suction pipe) or at the outlet of the mixing container, and transfers the mixture into the delivery line. Actual delivery can be achieved by means of a vacuum suction device or pressure chamber, which gently introduces the electrode mixture into the line. Preferably, a suction delivery device is used. A cooling effect can be achieved when the transport gas used in the pneumatic delivery device is cooled or mixed with waste gas generated by sublimation or evaporation (which originates from the liquid gas added to cool the mixture).

[0035] In a preferred embodiment, liquid gas (e.g., liquid nitrogen or liquid carbon dioxide) is also introduced into the mixture in solid form as dry ice for cooling. This significantly accelerates cooling within the mixing vessel. For example, by adding 10 kg of dry ice, 100 kg of a plastic, fibrous material can be cooled from 90°C to below 20°C in less than 3 minutes. If cooling is performed solely by a double-walled mixing vessel, a cooling time exceeding 30 minutes must be set for the cooling process. The amount of liquid gas or dry ice added is preferably determined such that the target temperature is reached as quickly as possible through complete vaporization or sublimation, i.e., cooling by at least ΔT = 5°C, but without the mixture being cooled below a minimum removal temperature of 24°C due to vaporization or sublimation. The faster the cooling process of the mixture proceeds, the less steel in the mixing vessel is cooled, due to the limited heat transfer from the mixture to the vessel walls. This minimizes the required amount of liquid gas added and the degree of cooling of the mixing vessel.

[0036] If dry ice or liquid nitrogen is introduced into the mixing vessel before removal, the pressure within the vessel increases due to the sudden development of the gas during sublimation or evaporation, which can support the feeding device. Furthermore, the resulting gas has a very low temperature, thus further cooling the electrode mixture as it flows into the delivery line and comes into prolonged contact with it. This effect is particularly pronounced in the case of thin-stream delivery (also known as flow delivery) due to the large surface area for mass and heat exchange between the electrode mixture and the gas. To prevent excessive temperature drop, a warmer gas (e.g., ambient air) can be mixed with the gas produced by evaporation or sublimation. This also avoids, for example, condensation effects on cold pipes.

[0037] At the end of the transport path, the electrode material is separated from the gas in a material separator. Here, a cyclone separator, deflector separator, or filtration system can be used to gently separate the material and transfer it, for example, to a buffer container.

[0038] In another preferred embodiment, the electrode mixture after step 2) is transferred to a buffer container, which is preferably temperature-controlled and serves as a cooling device in steps 3) and 4). The buffer container is preferably implemented with double walls, through which cooling fluid can flow, and / or has thermal insulation. Particularly preferably, the electrode mixture moves within the buffer container. This can be achieved by a stirrer, a gas dispersion device using nozzles, or by a continuously flowing, appropriately temperature-controlled compressed gas in the form of a fluidized bed or vortex bed.

[0039] Therefore, the buffer container itself can be used as a cooling device. Alternatively or additionally, a separate cooling device can be provided, such as the pneumatic conveying device with cooled conveying gas described. To prevent the particles of the electrode mixture from sticking together, a stirring tool can be provided in the buffer container to agitate and loosen the mixture until it can be discharged, for example, into a calender.

[0040] In a preferred embodiment, the electrode mixture after step 4) is applied to a sieving device, and only the undersize is used as the modulated electrode mixture for manufacturing the electrode. Here, the sieving device can be arranged in a buffer reservoir or after the buffer reservoir. The electrode mixture is separated into undersize and oversize by the sieving device, wherein the diameter of the component collected in the oversize is larger than the mesh width of the sieving device. The undersize loosened by sieving can be metered and distributed more easily and uniformly into, for example, the gap in a calender.

[0041] Preferably, the mesh width of the screening device is less than 10 mm, more preferably less than 5 mm, and very particularly preferably less than 2 mm.

[0042] In a preferred embodiment, the oversize material is guided into a mixing container, a buffer container, or a conveying line. Alternatively, the oversize material may be guided into a pulverizing device (e.g., another mixer). Thus, the oversize material can be recovered. Preferably, it is returned to a buffer container, or, if a pneumatic conveying line is provided for removing the electrode mixture from the mixing container, it is returned to that conveying line. Alternatively, the oversize material may be transferred to a pre-storage container or separator, which transfers the material as part of the electrode mixture into the mixing container, so that it is heated to temperature T along with fresh raw materials during the preparation of the electrode mixture. H >45℃, and produces a uniform electrode mixture composed of new and recycled materials.

[0043] In another preferred embodiment, a friction screen or vortex screen is used as the screening device, preferably in a manner that leaves no residue on the screen. By using a friction screen or vortex screen, such as a rotor, a considerable force is applied to the material, causing larger clumps to break up, thus significantly reducing the amount of residue on the screen. Particularly preferably, the force is adjusted so that no residue remains that needs to be retrieved. Thus, retrieval can be eliminated.

[0044] Finally, according to the invention, dry electrodes can be manufactured from the electrode mixture prepared in this manner. For this purpose, the electrode mixture is supplied to, for example, a calender and calendered into a web, wherein any protruding edge strips of the web are subsequently separated, for example, cut off, to ensure uniform width of the web. The separated edge strips are guided into a mixing container, a buffer container, or a conveying line. If an electrode foil is applied using a powder coating process prior to calendering, excess powder can be returned to the process in the same manner. The same applies to dust generated and sucked up due to the handling of the electrode mixture at the feed point of the coating unit.

[0045] The calendering process plays a decisive role in shaping and compacting the electrode to achieve the desired electrochemical properties.

[0046] During calendering, the electrode mixture is rolled or compacted into a film by a pair of rolls or a row of rolls, and pressed onto a current collector (typically copper for the anode or aluminum for the cathode) at the end of calendering or during calendering. This forms a uniform, dense layer with a defined thickness and structure. This process directly affects the porosity, thickness, and adhesion of the electrode mixture to the current collector. Depending on the type of battery to be manufactured, a sandwich structure (electrode mixture and current collector) can then be wound or stacked. In the case of winding, the anode and cathode strips are wound together with the separator into a helical structure (typically for cylindrical or prismatic batteries). In the case of stacking, the electrodes and separator are stacked layer by layer (typically for pouch cells).

[0047] By retrieving edge strips or excess material, materials can be recycled, thereby reducing production costs. In another preferred embodiment, if the excess material is in the form of a compressed film rather than in bulk, a crushing device is provided to break the separated edge strips into smaller strip segments.

[0048] Separated strips, typically in the form of continuous ribbons of varying widths, can be continuously guided into a crushing device by means of a conveyor belt or suction flow so that they can be reused during the production process.

[0049] For example, a batch mixer is suitable as a pulverizing device, in which oversize material (if any) and strips are collected or fed in batches. By pulverizing the mixture in a short time, transportable fine-grained products, such as lumps or powders, can be produced, which have the same properties as electrode mixtures prepared in a mixing vessel.

[0050] Preferably, the material can then be pneumatically removed from the intermittent mixer and transferred to a buffer container along with fresh raw materials. If the structure is tall enough, as an alternative to pneumatic removal from the pulverizing mixer, the pulverizing mixer can be positioned above the buffer container for pneumatic removal of the mixture from the main mixer and for direct gravity discharge of the mixture into the main mixer via a bottom venting device.

[0051] Since the oversize material and edge segments are continuous, a continuous crushing device, such as a continuously operating mixer or mill, like a rod mill or impact mill, is proposed in the preferred embodiment. The crushed final product can fall directly into a buffer container at the discharge point, or it can be pneumatically transferred to the buffer container.

[0052] Alternatively, edge strips can be supplied to the friction screening device. Attached Figure Description

[0053] Other advantages, features, and application possibilities of the invention will become clear based on the following description of preferred embodiments and the accompanying drawings. In the drawings:

[0054] Figure 1 A system for performing a first embodiment of the method according to the invention is shown.

[0055] Figure 2 A system for performing a second embodiment of the method according to the invention is shown, and

[0056] Figure 3 A system for performing a third embodiment of the method according to the invention is shown.

[0057] Figure 1 A schematic diagram of a system for performing a first embodiment of the method according to the invention is shown.

[0058] A dry electrode mixture is prepared in mixing container 1, with minimal or no solvent added (e.g., low-boiling-point solvents, high-boiling-point solvents, or water). However, the addition of a small amount of low-boiling-point solvent is not excluded to activate the binder surface. Here, the proportion of volatile solvents (i.e., low-boiling-point solvents) in the mixture is less than 5%. In this embodiment, mixing container 1 can rotate about mixing container rotation axis 4, but it can also be implemented as stationary. A mixing tool 2, rotatable about mixing tool rotation axis 5, is arranged inside mixing container 1. The mixing container walls and bottom are implemented as having double walls, allowing a cooling or heating medium to be supplied between these two walls to heat or cool the mixing container, thereby also heating or cooling the mixture contained therein. However, only the mixing container walls or only the mixing container bottom may be implemented as having double walls, with a cooling or heating medium flowing through them. Furthermore, the mixing tool itself may also be implemented as having double walls, with a heating or cooling medium flowing through it.

[0059] A suction gun 3 is also provided, which is connected to a first pneumatic delivery line 11. The electrode mixture prepared in the mixing container 1 can be removed via this pneumatic delivery line using a pneumatic conveying device. A particle size measuring device 8 is arranged in the first pneumatic delivery line, providing feedback on the particle size within the line. This information can be used to adjust the mixing process in the mixing container 1, for example, by changing the rotation speed or mixing time.

[0060] The electrode mixture is prepared in mixing container 1, and it is necessary to heat the mixture to a temperature above 45°C. To facilitate easier removal of the electrode mixture, it is cooled by at least ΔT = 5°C, and in this example, to a temperature below 35°C, by introducing a cooling medium between the walls of the double walls of mixing container 1. The electrode mixture is then converted into a conveyable bulk material by the movement of mixing tool 2. For example, it can be cooled to 30°C. The still warm but conveyable electrode mixture is then transferred via suction gun 3 to a first pneumatic conveying line and introduced into buffer container 7. In this embodiment, buffer container 7 has at least a partial double jacket that allows the supply of cooling medium between the two walls of the double jacket. Therefore, the electrode mixture is cooled in the buffer container by at least 4°C, preferably to a temperature below 19°C. To support pneumatic conveying, vacuum pump 19 is disposed above buffer container 7. Gas-solid separator 38 is located in the upper portion of the buffer container.

[0061] To support cooling and / or material discharge, a gas dispersion device 36 is provided in the illustrated embodiment, through which gas can be blown into the electrode mixture contained in the buffer container 7. A friction sieving device 12 with a rotor is arranged at the outlet of the buffer container 7, and the electrode mixture is supplied to the friction sieving device by means of a screw conveyor.

[0062] The friction sieving device is configured to break down any potentially large particles by introducing mechanical force, thus preventing oversize. The undersize is then introduced into the feeding device 21 via a transfer device 22. The weight of the electrode mixture being introduced or discharged can be determined and controlled accordingly by means of a weighing unit 23. Furthermore, the buffer container 7 may also be equipped with a weighing unit or other sensors for filling status control and metering of material discharge. The discharge from the feeding device 21 is guided to a multi-roll calender 13, which forms a uniform web 14 from the electrode mixture. Uneven strips 15 on the edges of the web 14 are separated by a cutting device 24, causing them to fall into a receiving device 16. The receiving device 16 is connected to a separator 37 arranged above the mixer 1 via a second pneumatic conveying line 10. To ensure pneumatic conveying, a gas delivery port 25 is arranged on the receiving device 16, and a vacuum pump or a correspondingly high-power blower is arranged above the separator 37. A Venturi nozzle 9 is disposed in the second pneumatic delivery line 10. In the Venturi nozzle 9, the airflow accelerates due to the narrowing and subsequent widening of the cross-section, applying high tension to the strip segment 15, which exists as a continuous strip, tearing the continuous strip into smaller segments, ideally only a few centimeters in size. Therefore, the Venturi nozzle 9 functions as a pulverizing device. The pulverized edge strip 15 falls into the separator 37 and can be transferred to the mixing container 1 via the metering dispensing mechanism 6. Preferably, the fragments of the edge strip 15 temporarily stored in the separator 37 are introduced into the mixer at the beginning of the fibrillation stage or during the fibrillation stage. This ensures that the edge strip segments are added uniformly to the electrode mixture. In particular, if the edge segments are added at the beginning of the fibrillation stage, these edge segments act as "inoculants," accelerating the fibrillation of PTFE in the electrode mixture. To monitor the filling status and control the metering dispensing, the separator 37 may be equipped with a weighing unit or a filling status sensor. A weighing buffer container can also be supplementarily connected between the metering and dispensing mechanism 6 and the mixing container 1 so that a defined amount of material can be weighed and fed into the mixing container.

[0063] Figure 2 A schematic diagram of a system capable of performing a second embodiment of the method according to the invention is shown. Wherever possible, [the following is used]... Figure 1 The same reference numerals are used to denote the same or nearly identical elements. Therefore, in the following text, in Figure 2 The text basically only shows the relationship with... Figure 1 The differences in structure. Figure 2 In this container, a liquid gas supply device 18 is arranged above the mixing container 1. At the end of the mixing process for preparing the electrode mixture at a temperature above 45°C, the electrode mixture is suddenly cooled by a temperature difference ΔT = 5°C, preferably to below 35°C, by means of the liquid gas 18 subsequently introduced into the interior space of the mixing container 1. This facilitates the removal of the electrode mixture from the mixing container 1. Once the liquid gas encounters the warm mixture, it evaporates. The resulting cold gas is then transferred via a suction gun 3 to the first pneumatic conveying line 11, supporting pneumatic conveying. Due to the low temperature of the evaporated gas, further cooling of the electrode mixture in the first pneumatic conveying line 11 is achieved through direct heat exchange between the mixture and the conveying gas. To support the cooling process, the conveying line 11 may be provided with a double-jacketed and / or insulating device through which the cooling medium flows. If cooling is not achieved in the first pneumatic conveying line 11, further cooling can be achieved in the buffer container 7 in the manner and method already described. The modulation, sieving, and metering of the electrode mixture are carried out in… Figure 2 The device shown performs, with Figure 1 The same as that shown and described in this context.

[0064] However, with Figure 1 In contrast, the second pneumatic delivery line 10 is no longer connected to the separator arranged above the mixing container 1, but is instead led back into the buffer container 7 via a Venturi nozzle for crushing the edge strips 15. As an alternative to or supplement to the Venturi nozzle, a crushing device 17, consisting of a blade rotor, further crushes the segments of the edge strips 15, and the crushed edge strips 15 are then led back into the buffer container 7. Therefore, Figure 1 and Figure 2 The main difference between the illustrated embodiments is that, on the one hand, cooling in the mixing container 1 is achieved by supplying liquid gas 18, and on the other hand, the generated edge strips 15 are not led back into the mixing container 1, but rather into the buffer container 7. It should be understood that in other equally preferred embodiments, the same applies to... Figure 1 The implementation method can also be achieved by implementing only one of the two variations described. Cooling in the mixing container 1 can also be achieved by a combination of wall cooling via a double jacket and evaporative cooling by liquid gas. If only liquid gas is used as the cooling medium, the double jacket can also be omitted in the mixer 1.

[0065] exist Figure 3The diagram illustrates a system that can implement the third embodiment of the method according to the invention. The mixing vessel 1 is again visible, but here it serves only as a heating medium supply device 34 for supplying the heating medium into the double-walled structure of the mixing vessel 1. The medium supply and discharge device 34 is implemented by means of submersible tubes (Tauchrohr) at different heights in open grooves on the outer wall of the rotating mixing vessel. The heating medium is guided in a loop via a heat exchanger by means of a pump. Here, the electrode mixture is transferred via a bottom venting device 26 and a transfer transition device 27 to a cooling mixer 28 arranged in a cascaded manner below the mixing vessel 1. The cooling mixer 28 has a coolant supply and discharge device 29, such as a rotary joint (Drehdurchführung), through which the cooling medium can be introduced into and discharged from the double-walled structure of the mixing vessel of the cooling mixer 28. Therefore, the still-warm electrode mixture is first transferred to a cooling mixer 28, which serves as a cooling device, and then transferred from the cooling mixer to a first pneumatic delivery line 11 via a suction gun 3, entering a buffer container 7. As a supplement to or even alternative to cooling via a double-jacketed system, cooling of the mixture in the cooling mixer 28 can also be achieved by adding liquid gas or dry ice. In this embodiment, the buffer container 7 has a stirrer 35, which provides further motion to the electrode mixture via a stirrer driver 30, thereby accelerating the cooling of the electrode mixture in conjunction with the double-jacketed cooling device 20. A friction sieving device 12 is also located at the outlet of the buffer container 7. However, in this embodiment using a planar sieving device, the force applied to the particles is smaller, resulting in oversize material 31, which is transferred to an intermittent mixer 32, which serves as a pulverizing device. Similarly, at the end of the calender, the edge strip 15 is separated from the uniform web by means of a cutting device 24. Edge strips 15 are also transferred via conveyor belt 33 to intermittent mixer 32, which has a blade-equipped agitator that shreds oversized particles and edge strips 15 into smaller pieces. These smaller pieces are then transferred via suction gun to a second pneumatic delivery line 10, where a venturi nozzle 9 can provide further shredding.

[0066] exist Figure 3In the system shown, particle size measuring devices 8 are respectively arranged in the first pneumatic conveying line 10 and the second pneumatic conveying line 11. Particle size measurement can be performed, for example, by means of optical measurement methods, and is used to detect deviations from the reference size distribution of the electrode mixture or the bulk material returned via the second pneumatic conveying line 10. This information enables an adjustment or control loop to adjust the size distribution of the electrode mixture already in the mixing container 1 by adjusting the tool speed, the temperature of the mixture, or the grinding time. Alternatively or in combination, the temperature in the buffer container or the operating parameters of the friction sieving device 12 can also be adjusted. To control the temperature of the electrode mixture in the buffer container, the buffer container is equipped with a contact or non-contact temperature sensor.

[0067] To regulate the temperature or flow rate of the transported gas, supplementary air 39 can be introduced into the transport line 10. The temperature and moisture content of the supplementary air can be regulated via a heat exchanger and / or absorber.

[0068] The method according to the invention greatly simplifies the preparation of electrode mixtures and the manufacture of dry electrodes from these mixtures by reducing cycle time and significantly improving quality. Furthermore, waste is greatly reduced by recovering excess materials.

[0069] Reference tag list

[0070] 1. Mixer with mixing container

[0071] 2. Mixed Tools

[0072] 3. Suction gun

[0073] 4. Container rotation axis

[0074] 5. Rotation axis of the mixing tool

[0075] 6. Metering and Distribution Mechanism

[0076] 7. Buffer container

[0077] 8. Particle size measuring device

[0078] 9 Venturi nozzles

[0079] 10 Second pneumatic delivery pipeline

[0080] 11 First Pneumatic Delivery Pipeline

[0081] 12 Friction Screening Device

[0082] 13 Multi-roll calender

[0083] 14 sheets

[0084] 15 Edge strips

[0085] 16 Receiving equipment for pneumatic conveying

[0086] 17. Crushing equipment

[0087] 18 Liquid gas

[0088] 19 Vacuum Pump

[0089] 20 Double-layer jacket

[0090] 21 Feeding equipment

[0091] 22 Transfer Transition Device

[0092] 23 Weighing Unit

[0093] 24 Cutting equipment

[0094] 25. Gas delivery

[0095] 26 Bottom venting device

[0096] 27. Transfer and transition device

[0097] 28 Cooling Mixer

[0098] 29. Coolant supply and discharge system

[0099] 30 Mixer Driver

[0100] 31. Oversized particles on the sieve

[0101] 32 Intermittent Mixer

[0102] 33 Conveyor Belt

[0103] 34 Heating medium supply and discharge device

[0104] 35 Buffer Storage Stirrer

[0105] 36 Gas Dispersion Device

[0106] 37 Separator

[0107] 38 Gas-solid separator

[0108] 39. Add air.

Claims

1. A method for preparing and modulating an electrode mixture, the electrode mixture comprising an active material, optional additives, and a binder, the method comprising the following steps: 1) The electrode mixture is prepared in a mixing vessel, wherein the mixture is heated to a temperature T during preparation. H T H >45℃, 2) Cool the electrode mixture in the mixing container to at least ΔT = 5°C, preferably to temperature T. MAX <35℃, but not lower than the removal temperature T E >24℃, 3) Remove the electrode mixture at the said removal temperature and supply the electrode mixture to a cooling device. 4) Using the cooling device, the electrode mixture after step 2) is cooled by at least 4°C, preferably to temperature T. K <19℃.

2. The method according to claim 1, characterized in that, The delivery line of the pneumatic conveying device used to remove the electrode mixture from the mixing container is configured as the cooling device in steps 3) and 4), and the delivery line preferably has a temperature T. G The gas is operated at <19°C, wherein preferably in step 2), between step 2) and step 3) and / or during step 3), dry ice or liquid gas is introduced into the mixing container, and gas generated by sublimation or evaporation is guided into the delivery line.

3. The method according to claim 1 or 2, characterized in that, The electrode mixture after step 2) is transferred to a buffer container, wherein preferably, the buffer container is temperature-adjustable and serves as a cooling device in steps 3) and 4), wherein the buffer container is preferably implemented to have double walls, wherein cooling fluid can flow between the two walls, and / or the buffer container has a heat insulation device, wherein particularly preferably, the electrode mixture moves in the buffer container.

4. The method according to any one of the preceding claims, characterized in that, The electrode mixture after step 3) is applied to a sieving device, and only the undersize material is used as the modified electrode mixture, wherein preferably, the mesh width of the sieving device is less than 10 mm, particularly preferably less than 5 mm, and most preferably less than 2 mm.

5. The method according to claim 4, characterized in that, The material oversize is guided into the mixing container, the buffer container, the pulverizing device, or the conveying line.

6. The method according to claim 4, characterized in that, Friction screening devices or, particularly preferably, vortex screening devices are used as screening devices, wherein they are preferably used in a manner that leaves no residue on the screen.

7. A method for manufacturing a dry electrode from an electrode mixture prepared by means of any one of the preceding claims, characterized in that, The electrode mixture is supplied to a calender and calendered into a web, wherein edge strips or excess material of the web are then separated to ensure uniform width of the web, and the separated edge strips or excess material are guided into the mixing container, the buffer container, or the delivery line.

8. The method according to claim 7, characterized in that, The device is equipped with a crushing device that divides the separated edge strips into smaller strip segments.

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