CALENDAR DOSING SYSTEM FOR THE PRODUCTION OF ELECTRODE FILMS OR FUEL CELLS OR CAPACITOR FILMS AND THE LIKE.

Abstract

The invention relates to a metering system for the process of dry-coating battery electrodes with a pulverulent product (4) which is applied to the roller gap (13) between two calender rollers (14, 15) in a continuous product flow, wherein a receptacle (9) which receives the product (4) is arranged in front of the roller gap (13), said receptacle being supplied via a conveyor trough (5) and the walls (10, 10a, 11) thereof being designed to diverge conically starting from an inlet baffle (29) and an upper filling gap (22) in the direction of an outlet gap (23) which lies opposite the roller gap (13).

Description

[0001]Calender dosing system for producing electrode foils or fuel cells or capacitor foils and the like. The invention relates to a calender dosing system for producing electrode foils for batteries or for fuel cells or capacitor foils and to a method for dosing powder material for producing such foils. Due to the dynamic growth of markets, coupled with simultaneous changes in the raw materials used in battery production, various solutions are currently being developed. DE 102017216570 A1 shows a method for producing an electrode arrangement which, however, does not employ a dry coating process. DE 102017218158 A1 uses a dosing system for dry coating in which a particle bed containing an active material, preferably lithium, is provided. The particle bed is applied to one side of a foil and dosed there to a specific thickness.However, a uniform, stable bulk density is difficult to achieve. Until now, dry coating was not known in the production of electrode foils for battery electrodes. Until now, the only known method was wet coating, which has the disadvantage of high energy consumption in drying the produced foils and an uncertain and difficult to control thickness of the produced foil. The disadvantage of wet coating processes was that highly environmentally harmful chemicals had to be used. Furthermore, with the previously known wet coating processes, it was not possible to achieve a thickness of the produced electrode foils below a certain minimum. However, staying below such a thickness is very advantageous because it can increase the capacity of the battery if thinner foils are used. This refers to a constant battery volume.The invention is therefore based on the object of proposing a calender dosing system for the production of electrode foils for battery electrodes, etc., as well as of further developing a method for operating the dosing system such that a dimensionally stable dry film is formed in a dry coating process with uniform powder distribution. To achieve the stated object, the invention is characterized by the technical teaching of the independent patent claims. Further developments arise from the subclaims. The invention therefore relates to the development of a dosing and storage system for the continuous supply of battery mass to a calender. For the dry production of battery electrodes, various starting products are mixed in a mixing process to form a battery mass. In various process steps (comminution, compaction), the battery mass is processed and then calendered to produce a dry film.The battery mass must be evenly distributed and fed across the calender's roll gap so that the gap is evenly filled and the production of a continuous dry film is ensured. Appropriate control of the fill level in the feed hopper is provided. The mixed starting product is highly cohesive and compacts when stored in relatively small quantities due to its time-, pressure-, and temperature-compacting properties. A dosing system was developed that enables parallel buffering and uniform discharge. The fill level and consistent refilling (control) in the feed hopper must be taken into account in the event of fluctuating calender performance and / or product quality. A further challenge is the high temperatures of 100–250°C of the rolls, which can lead to product changes and compaction, thus exacerbating the problem of undesirable cohesion.After the mixing process, the battery mass is compacted, for example in an extruder, and preferably crushed again using a screen or mill to make the product dosable. The product is dosed into a feed hopper via a vibrating chute, which is located above the calender rolls. The lower part of the feed hopper is called the chute and is open at the bottom to ensure product discharge into the calender. A constant fill level in the chute is ensured by means of at least one fill level sensor and control via the speed of the feed device. Instead of dispersing the product in a screen or mill, another embodiment can provide for the product to be dispersed using a pneumatic conveying system. This can be a conveying system with a separation tank in which the dispersed product is separated and removed for further processing.Likewise, pneumatic conveying alone may be sufficient for dispersion. In both cases, a sieve or mill can be omitted. In all cases, it is assumed that the product is dry, finely dispersed and free-flowing and thus suitable for bulk material. A preferred embodiment of the invention provides for the shaft to be conical, namely diverging in the direction of the outlet gap, which means that, starting from an upper filling gap, either only the front and rear walls and / or also the side walls widen conically downwards towards the outlet gap. In another embodiment of the invention, it can be provided that only the front and rear walls widen conically downwards towards the outlet gap, but not the side walls, which in this case are arranged parallel to one another.It is therefore a funnel-shaped shaft that widens conically on at least one side. This has the particular advantage that the product finds a storage area in the interior of the shaft above the outlet gap. In this area the product is preferably stored above the roller gap without compression and is then compacted into a stable dry film between the two opposing calender rollers. The lower geometry of the storage area is closed off by the outer surfaces of the calender rollers. The product is thus evenly spread and expanded in the storage hopper from the upper filling gap into the interior of the shaft due to the divergent cone shape. This means that any pressure zones that could form when filling the shaft are spread out and dissolved. The particle filling is therefore distributed pressure-free in the interior of the shaft.The conically divergent shape of the chute has the further advantage of creating a stable buffer zone for the particle bed in the outlet area. This buffer zone stores the material to be processed smoothly, pressure-free, and free-flowing above the roll gap before being taken up into the nip of the calender rolls. The side walls of the storage hopper taper towards the outlet end and extend into the calender gap to ensure the smallest possible distance to the rolls. This prevents the product from leaking out sideways, resulting in higher quality and a smaller edge zone of the calendered film. Furthermore, potential dust escape is minimized. By mounting the hopper on the bearing blocks of the outer roll, it is possible to move the hopper together with the roll when the roll gap changes.Instead of mounting it on the outer roller, it can also be mounted on a different roller. Another feature is that the feed hopper is connected to the permanently mounted vibrating chute via an elastic seal to largely prevent any transmission of vibrations to the feed hopper when the vibrating chute is in operation. The feed hopper has a conically tapered inlet area that is offset in height. A chicane is built into this inlet area to loosen and evenly distribute the product in this area. The chicane slows the product down and distributes it evenly into the hopper. The resulting enlargement of the inlet area allows the dosing hopper to be moved towards the vibrating chute and also allows changes to the throw parabola of different products when the product is discharged from the chute-side discharge edge into the inlet area of ​​the chicane in the feed hopper.According to a further preferred feature, the feed can take place across the entire width of the roll gap, although this is not essential to the solution and can lead to the product spilling laterally over the outer surface of the calender rolls. In another preferred embodiment, the width of the outlet gap of the shaft is preferably 30 - 50 mm smaller than the length of the calender rolls. Thus, the width of the outlet gap corresponds to approximately 80 - 90% of the width of the calender rolls. By calendering, the product is pressed into a film whose width is greater than the outlet gap and preferably smaller than the length of the calender rolls. The dispersed product does not have to be fed across the entire width of the inlet gap of the storage container, but only across a portion. The product then automatically distributes itself across the entire width of the shaft.The shaft depth, i.e. the distance between the front and rear walls, is in the range of 10 to 50 mm, because this reduces the bulk pressure on the powder since the walls of the feed hopper support the product with friction. The height of the shaft is preferably around 500 mm and lies in the range of 100 to 1000 mm. The width of the shaft is adapted to the roll width of the calender rolls and can range from 100 to 1600 mm. The conically diverging walls of the feed hopper have a difference in width between the filling gap and the outlet gap of preferably 10 mm. This difference in width can range from 5 mm to 40 mm. If the dimensions of the feed hopper were larger, a larger product volume could be accommodated in the feed hopper, but this could also lead to undesirable pressure effects on the pressure-sensitive powder.The powder to be dosed has pressure-sensitive properties. It preferably consists of particles approximately 500 micrometers in size, consisting of metal oxides and a powdered binder made of plastic particles, as well as conductive carbon black. This type of active material is used for coating battery cathodes, while graphite powder is used instead of metal oxides for coating anodes. It preferably has an FFC value in the range of less than 4, meaning it is poorly flowing to cohesive. During processing of the highly cohesive powder, it was discovered that the powder is particularly pressure-sensitive and can react undesirably with the binder particles made of plastic material when subjected to pressure. If too much pressure is exerted on the powder, it coagulates, which is undesirable and prevents further processing as a homogeneous powder mass.For this purpose, the dosing system according to the invention is designed to ensure particularly pressure-free dosing of the pressure-sensitive powder. An additional embodiment of the feed container provides overfill protection. Overfilling is detected via at least one fill level sensor, dosing is stopped, and any bridges that may form in the feed container, particularly in the area of ​​the baffle, the filling gap, or the shaft, are mechanically released via an electric motor and / or pneumatically driven unit. This prevents possible overfilling while the calender can continue running. According to a further feature of the invention, a suction and extraction point is provided above the vibrating chute and the feed container to generate a slight negative pressure in the feed container in order to prevent possible dust escaping from the dosing system.To minimize product removal during dust extraction, a cross-sectional expansion is provided at the outlet of the vibrating chute to increase the volume. The removed product can be recycled to the upstream process if necessary. To prevent heat transfer from the rollers to the feed hopper and the product, cooling elements, which operate with water, for example, can be installed at the front and rear of the feed hopper. Low product temperatures improve flowability and removal between the calender rollers. The subject matter of the present invention arises not only from the subject matter of the individual patent claims, but also from the combination of the individual patent claims with one another.All information and features disclosed in the documents, including the abstract, in particular the spatial configuration shown in the drawings, could be claimed as essential to the invention, insofar as they are new, individually or in combination, compared to the prior art. The use of the terms "essential" or "according to the invention" or "essential to the invention" is subjective and does not imply that the features so named must necessarily be part of one or more patent claims. The invention is explained in more detail below with the aid of a drawing which merely illustrates one embodiment. Further essential features and advantages of the invention will become apparent from the drawing and its description. They show: Figure 1: a schematic process diagram of the dosing device according to the invention. Figure 2: a side view of a schematically illustrated dosing device.Figure 3: the front view of the dosing device according to Figure 2. Figure 4: a perspective side view of the feed container for powder dosing according to the invention. Figure 5: a perspective side view of the dosing system with further details. Figure 6: a longitudinal center section through the illustration in Figure 5. Figure 7: the perspective side view of the arrangement according to Figure 5. Figure 8: a plan view of the feed side. Figure 9a: section through the filling shaft in a first embodiment with flat guide surfaces. Figure 9b: the same illustration as Figure 8a, but with convex guide surfaces. Figure 10: a side view of the dosing system. Figure 11: a vertical section through the feed container. Figure 12: a vertical section through the dosing system. Figure 13: an enlarged illustration from Figure 12 showing the inlet-side chicane. Figure 14: a section through the outlet end of the feed container.Figure 15: a perspective view of a further embodiment in which two dosing systems arranged as mirror images of one another are provided for coating a current collector foil on both sides. Figure 16: the same illustration as Figure 15 in a perspective side view. Figure 17: a modified embodiment compared to Figures 15 and 16, which used a one-sided coating. Figure 18: the side view of Figure 17. Figure 19: the serial connection of two roller gaps. Figure 20: the same illustration as Figure 19. Figure 1 shows a schematic of a dosing system 1 for feeding dry powder to a calender 14, 15. Starting from an upper mill 18 arranged on the inlet side, in which a fine dispersion of the dry powder with a preferred particle size of approx.500 µm is desired, an addition and mixing of different particles, namely, for example, a powder 19 and a binder 20, takes place in the inlet area of ​​the mill 18. The thus mixed and finely dispersed powder is filled as product 4 in the direction of arrow 3 into a feed hopper 2 of the system and reaches a vibrating conveyor trough 5 at the outlet of the feed hopper 2, in which the product 4 is evenly distributed and brought to a specific outlet width at the outlet 8. It can be provided that the conveyor trough 5 is cooled. In this way, the filling gap 22 of a storage container 9 arranged at the outlet 8 of the conveyor trough 5 is evenly fed via the inlet chicane 29. The inlet chicane 29 tapers conically and the front and rear are offset in height from one another. Further details are explained in Figure 13.The lower part of the storage container 9, which is referred to as the shaft 32 and begins below the filling gap 22, is preferably doubly conical and has walls that diverge from one another, namely a rear wall 10, an opposite front wall 11, and side walls 10a that diverge conically from the filling gap 22 in the direction of the lower outlet gap 23. The opposite side walls 10a have the same shape, so that the arrangement of the walls 10, 10a, 11 results in a shaft 32 that widens downwards in a funnel shape. However, it was pointed out in the general description that in some applications it is sufficient to design only the front and rear walls 10, 11 to widen conically, while the side walls 10a, 10b run parallel to one another.Another embodiment provides that the side walls 10a, 10b widen conically towards the outlet gap 23, while the front and rear walls 10, 11 run parallel to one another. In the lower region of the shaft 32, a storage area 12 for the product 4 is formed in the interior, which extends from the interior of the shaft 32 to the nip 13 of the calender rolls 14, 15. The product can thus reach the nip 13 from the storage area 12 as a loose, flowable bulk material due to gravity, where it is formed into a stable dry film. An ultrasonic generator, a knocker, or a vibrator 21 can be arranged on one or more walls of the storage container 9, which ensures a uniform distribution of the product 4 in the interior of the storage container 9 and in particular in the storage area 12. An ultrasonic transducer, knocker or vibrator 21 may additionally be arranged on the conveyor trough 5 to remove possible product deposits on the conveyor trough 5.In the nip 13, the dry product is compacted by the two counter-rotating calender rolls, which are preferably heated. It reaches a flowable state, so that a stable, dry product film 4a is formed at the exit of the nip 13, which is fed to further processing 17. If the temperatures of the calender rolls 14, 15 are sufficiently high, cooling elements 30 can be provided on the front wall 11 and / or rear wall 10 and / or on the side walls 10a of the feed hopper 9. Level sensors 24b-24e are provided on the feed hopper 9 to monitor and regulate the fill level in the feed hopper 9. Should overfilling nevertheless occur, any bridges that may undesirably form from the product 4 can be detected in the inlet chicane 29 by the level sensor 24a and removed by a distribution element 28, e.g., a motor-driven or pneumatically driven rake.A further feature of the invention serves to increase occupational safety and aims to largely prevent dust from escaping into the environment. For this purpose, a negative pressure is provided at the extraction nozzle 26 with an extraction system and at the intake nozzle 27 an intake via an intake filter. Further details are explained with reference to Figure 5. A dust-tight connection between the conveyor trough 5 and the storage container 9 is ensured by an elastically deformable seal 31, which prevents the transmission of vibrations from the conveyor trough 5 to the storage container 9. Further details can be found in Figures 2 and 3. In a modification of the schematic representation in Figure 1, Figures 2 and 3 show preferred design details of the same parts as in Figure 1.Figures 2 and 3 show that the outlet gap 23 of the storage container 9 projects into the roller gap 13 to enable the sensitive product to be fed into the roller gap 13 with as little pressure and compression as possible. Lateral extensions 25 of the side walls 10a, 10b are provided, which project beyond the opening of the outlet gap 23 to ensure a uniform distribution of the product 4 across the width of the roller gap 13. Figure 3 also shows that the opening of the storage container 9 projects into the roller gap 13 as a lateral extension 25 of the side walls 10a, 10b to ensure a pressure-free and friction-free feed of the dry product from the accumulation area 12 of the storage container 9 into the roller gap 13.With regard to Figure 1, it should also be noted that the direction of vibration 51 of the vibration drive 6 is directed obliquely to the horizontal, with an angle to the horizontal being in the range of 10 to 50°, and an angle of 20° is particularly preferred. Figure 4 shows an exploded view of the parts of the storage container 9, with the same reference numerals applying to the same parts. Figures 5 to 7 show further details of the structurally designed dosing system for the powder feed. Figure 5, in conjunction with Figures 6 and 7, shows a flexible connection 46 to the feed hopper 2 (only shown in Figures 1 and 2), via which the product 4 is fed into the inlet area of ​​the conveyor trough 5 via the flexible connection 46. The conveyor trough 5 therefore forms a small conveyor device 5, 6 with the vibration drive 6 and the motor 52, which vibrates in the direction of arrow 51. First, Figure 5 describes the particularly environmentally friendly powder processing.Air is extracted from the interior of the conveyor trough 5 through an extraction nozzle 26 on the conveyor trough 5, specifically in the area of ​​a larger-volume channel extension 47. The extracted air is contaminated with powder and is drawn in the direction of arrow 40 by a fan 43, the pressure side of which opens into a filter 44, which separates the powder material and releases the purified air into the atmosphere. The arrangement of a larger-volume channel extension 47 ensures extraction with a high volume flow without entraining product. Thus, hazardous product dust is removed in the channel extension 47 of the conveyor trough 5 before it reaches the storage container 9.A further feature for keeping the dosing device dust-free is that, due to the negative pressure in the conveyor trough 5, outside air is sucked in the direction of arrow 41 via a filter 42 and an intake nozzle 27 into the interior of the storage container above the product transfer chamber 56 and above the inlet chicane 29. This provides additional flushing of the product 4 with fresh air before it enters the inlet chicane 29, which improves its flowability. This ensures that a targeted flow, free of suspended particles, takes place in the product transfer chamber 56, whereby this flow is preferably directed vertically downwards towards the inlet chicane 29. Figure 12 shows that the conveyor trough 5 essentially consists of two different regions with different cross-sectional areas and thus different volumes.The smaller volume assigned to the feed hopper 2 is referred to as the inlet area 48 in Figure 12, and this inlet area 48 merges into a larger volume of a discharge area 49, so that the powder 19 is conveyed gently and without pressure on the bottom surface of the conveyor trough 5 as shown in Figure 11. The air extraction in the direction of arrow 45 takes place in the larger-volume discharge area 49. This ensures that the discharge area 49 is free of particles because the discharge area 49 is constantly flushed with fresh air, which flows in the direction of arrow 41 via the filter 42 into the discharge area 49. In addition to the aforementioned extensive removal of suspended powder particles in the discharge area 49, a further advantage of air flushing is that a constant negative pressure is maintained in the conveyor trough 5 to prevent dust particles from escaping into the environment. This negative pressure is also present in the product transfer chamber 56.The negative pressure therefore extends to the product surface that forms in the retention area 12, which is shown in Figure 11 with the various, conical flowing product surfaces 57, 57', 57'', 57'''. The product surface 57 can therefore assume a single flow shape in these areas corresponding to a single product surface 57, 57', 57'', 57''' shown there, according to Figure 11. The product surface 57 can also assume a product surface not shown, which is located between the product surfaces 57 and 57'''. The wedge-shaped flow pattern in Figure 11 is directed vertically downwards, with the fill level being optionally monitored by the fill level sensors 24b to 24e that are arranged vertically aligned with one another. The control of the fill level of the product surface 57 in the area of ​​the fill level sensors 24b to 24e is preferably carried out via the control of the feed at the feed hopper 2.For this purpose, a dosing device (not shown in Figure 1) is used at the inlet of the feed hopper 2 or at the inlet of the mill 18. Thus, the fill level in the storage container 9 is controlled by detecting the product surface 57 as a function of a dosing device (not shown in detail), which is arranged at the inlet of the feed hopper 2 or at the inlet of the mill 18. In a preferred embodiment, the fill level sensors 24, 24a-24e operate using a capacitive measuring principle, which means that they measure the conductivity of the conductive powder and thereby determine the fill level and the product surface 57 according to Figure 11 and accordingly control the dosing device at the inlet of the feed hopper 2 or at the inlet of the mill 18.Instead of using capacitive level sensors 24, 24a-24e, other level sensors with different principles can also be used, such as those based on the light barrier principle, inductive level sensors and optical sensors, or even laser-supported level sensors 24. The level sensors 24 can also be designed as resistance measuring sensors. Figure 6 is a longitudinal section compared to Figure 5 and shows the same parts with the same reference numerals. Here, the direction of the arrow 7 indicates the product flow, which is conveyed via the conveyor trough 5 due to vibration, whereby the channel extension 47 is also shown. The conveyor trough 5 forms the outlet 8, which forms the transition into the vertically adjoining storage container 9. Figure 7 shows further preferred features of the invention. The direction of vibration of the conveyor trough 5 is inclined in the direction of the arrow 51 at a specific angle to the horizontal.In the general description it has already been stated that a preferred angle of 20° is provided, whereby this angle can vary in the range between 0° and 50°. The conveyor trough 5 can be adjustable in its inclination to the horizontal in order to avoid overfilling of the product during transfer to the inlet chicane 29. In another preferred embodiment it is provided that the conveyor trough 5 forms a conveying plane in the horizontal direction. From Figure 7 it can be seen that the outlet 8 of the conveyor trough 5 opens into a sealing sleeve 31. This has the advantage that the vibrations of the conveyor trough 5 are not introduced into the feed container 9 of the dosing system due to the vibration-damped sealing sleeve 31. This keeps vibrations away from the feed container 9 which could lead to inaccurate film formation in the nip between the calender rolls 13, 14.Likewise, undesirable compaction or compression shocks on the product 4 flowing into the filling gap 22 can be avoided, which could lead to undesirable bridging in the product 4, which is thus prevented. In another embodiment of the invention, it can be provided that the feed hopper 2 does not sit directly on the conveyor trough 5, but that two conveyor troughs are present which are connected to one another at an angle of preferably 90°. The conveyor troughs can be connected to one another at an angle of 0 to 360°. The conveyor troughs are then fluidly connected to one another, and this ensures that the feed hopper 2 is no longer arranged centrally in the area of ​​one conveyor trough 5, but rather eccentrically. This enables lateral feeding of the product, which leads to a space saving directly vertically above the dosing device 1.The eccentric arrangement of the feed hopper 2 with two conveyor troughs 5, 5 connected to one another perpendicularly in a fluid manner has the advantage that the current collector foil 54 shown in Figures 15 and 20, which requires a large amount of vertical space, can be guided collision-free without being limited by a single, directly laterally adjoining conveyor trough 5. In a preferred embodiment, Figures 5 to 7 show that the feed hopper 2 also opens into the conveyor trough 5 via a vibration-damped, flexible connection 46. Figures 5 to 7 show a fixed sleeve which can be connected to a flexible collar as a flexible connection 46. Figure 8 also shows four spaced-apart holders 58 in the manner of eyebolts, which serve to raise or lower the feed container 9 in the vertical direction from the roller gap 13.Using the holder 58 formed by the eyebolts 58, the feed container 9 is positioned vertically on the calender arrangement comprising the two calender rolls 14, 15. The two extensions 23 (Figs. 3 and 4) arranged in the outlet gap 23 engage more or less into the roll gap 13 in an adjustable and lockable manner. Essentially, it can be seen from Figure 4 in conjunction with Figures 5 to 7 that the feed container 9 consists of two side walls 10a, 10b that open parallel to one another or diverging from one another, which define a specific shaft width of the shaft 32. The shaft width of the shaft 32 is continuously adjustable by the adjustability of at least one side wall 10a and / or 10b of the feed container 9, and thus also the overall degree of divergence of the shaft 32.The degree of divergence can vary in the range between 0° and 20° and is preferably at a divergence angle of 1°. In another embodiment of the invention, a fixed shaft width and a fixed divergence angle can also be provided, which is characterized by non-adjustable side walls 10a. The calender rolls 14, 15 are installed in a calender frame formed from shield plates. The axes of the calender rolls 14, 15 are accordingly rotatably mounted in the associated bearing blocks. The bearing arrangement is not shown in detail. The bearing blocks of the calender rolls 14, 15 are preferably translationally displaceable within the shield plates. This allows the size of the roll gap 13 to be adjusted. The roll gap 13 has a preferred size, corresponding to the film thickness, of 0 to 600 µm, whereby a range between 0 and 1,000 µm is possible.During maintenance, it is possible to move the calender rolls 14, 15 against each other in order to carry out certain maintenance tasks. During operation, however, a distance between the calender rolls 14, 15 can be adjusted, ranging from greater than 0 to 600 µm. A value greater than 0 is set here. Each calender roll 14, 15 is rotatably mounted in bearing blocks. The bearing blocks are translationally fastened in the shield plates, and the feed hopper 9 is attached to the bearing blocks. The entire feed hopper 9, with its lower section, is adjustably attached to the bearing blocks of a roll. The term calender frame is synonymous with the previously mentioned shield plates. The solution not only requires that the bearing blocks be connected directly to the underside of the feed hopper 9, but other connection options can also be provided.Figure 8 shows a top view of the conveyor trough 5 in conjunction with the transition to the feed container 9. Also shown is the sealing sleeve 31, which absorbs the vibrations of the conveyor trough 5 and prevents the vibrations from being transmitted to the feed container 9. It is preferred if, as shown in Figures 1 and 8, a first ultrasonic transmitter 21 is arranged directly opposite the feed hopper 2, namely preferably opposite the flexible connection 46. A further ultrasonic transmitter 21 (on the right in Figure 8) projects directly into the upper part of the outlet 8, because powder buildup can occur there, which is then comminuted.Figure 10 shows the additional ultrasonic transducers 21, namely a first 21a on the left side in the inlet area of ​​the conveyor trough 5, and the additional ultrasonic transducer 21b in the area of ​​the inlet chicane 29, where preferably two opposing ultrasonic transducers 21b and 21c are arranged at an angle to one another. A third ultrasonic transducer 21d is arranged in the accumulation area 12, i.e., in the area of ​​the product surface 57 between the fill level sensors 24a-24e that detect the product surface. It is also possible, although not shown in the drawing, for another ultrasonic transducer to be arranged on the rear wall 10 opposite the ultrasonic transducer 21d. Instead of the ultrasonic transducer 21a-21d shown here, other vibration generators can also be used, such as vibrators that operate with mechanical imbalance, air injection devices, mechanical knockers, or the like.The term ultrasonic generator 21 is therefore only meant to be representative of all possible loosening devices. Figures 9a and 9b show the shaft 32 with the accumulation area 12, wherein the geometry of the shaft 32 touched by the product 4 is shown above the roller gap 13. Figure 11 shows the shaft 32, which is delimited in the vertical direction by the outlet gap 23 and the filling gap 22 or by the extension 25 of the side walls 10a. The difference between Figures 9a and 9b is that the opposite side walls 10a form guide surfaces 35 between them that are in contact with the product, wherein the guide surface 35 in Figure 9a is designed as a straight line, while the guide surfaces 35 in Figure 9b is designed as a convex curve. The distance 59 in Figure 9a shows that the width of the shaft 32 is smaller by the distance 59 than the length of the calender rolls 14,15.The arrangement of the distance 59 ensures that the product does not flow out laterally over the outer boundary of the calender rolls 14, 15 in an uncontrolled manner. The difference between the straight guide surface 35 in Figure 9a and the convex guide surface in Figure 9b is that with opposing, convex guide surfaces 35, improved product centering of the product 4 is achieved. The convex design of the guide surfaces 35 in Figure 9b ensures that no product adhesion can occur in the corners of the filling chute 32 because an angle greater than 90° is formed, thus preventing bridging. Figure 10 shows that the distance between the two calender rolls 14, 15 is adjustable in the direction of the arrow 60, whereby it may be sufficient to design only one calender roll 14 or 15 to be adjustable, while the other is fixed.For repair and maintenance purposes, however, it is preferred if both calender rolls 14, 15 are designed to be mutually displaceable and adjustable. Figure 10 also shows that the film 4a comes out straight at the outlet of the calender rolls 14, 15, but in practice, different speeds of the calender rolls 14, 15 ensure that the film 4a is bent at the calender outlet either in the direction of arrow 33 or in the direction of arrow 34. It is then guided to further processing devices that are not shown here. In the other case, in which only one of the calender rolls 14 or 15 is translationally displaceable, the feed container 9 could be fixedly attached to the shield plates for holding a calender roll 14 or 15. The feed container 9 then does not have to move when one of the calender rolls is displaced.Figure 10, in conjunction with Figure 14, shows an arrow-like, downwardly tapering extension 25 of the side walls 10a. This is not a conical, straight constriction, but rather a specific radius 63 that is larger than the radius of the calender rolls 14, 15. It can also be the same size as the radius of the calender rolls 14, 15. The differences between the preferably larger radius 63 of the shaft-side extension 25 and the smaller radius of the calender rolls 14, 15 prevent bridging of the product 4 in the accumulation area 12.It is preferred if the rear wall 10 and the front wall 11 do not open downwards in a linearly diverging manner in the accumulation area 12, but rather have radially outward-facing vanes 64 in this outlet gap 23, in order to allow expansion of the powder material in the outlet gap 23 shortly before the calender roll gap without the accumulation area 12 formed by the rear wall 10 and the front wall 11 becoming mechanically deformed. The vanes 64 therefore form a mechanical stiffener for the shaft-side outlet area. The center of the protrusion 65 is offset slightly vertically downwards, so that there is a smaller upper distance and a larger lower distance to the calender roll, whereby the clear distance between the calender roll and the protrusion 65 opens downwards in a diverging manner. The vanes 64 form lateral stiffeners for the front wall 11 and rear wall 10.These stiffeners are necessary to prevent the bulk material from pushing the walls 10, 11 apart. Instead of the mechanical vanes, which only serve to reinforce the front and rear walls in the outlet area, other reinforcement measures can be used, such as welded profiles, supports, or thicker material walls. The vanes 64 also have the advantage that the product flow is less likely to interrupt. Figure 11 shows a sectional view through the inlet from the conveyor trough 5 into the feed hopper 9, where it can be seen that the powder 19 flows vertically downwards from the powder bed and runs onto an inlet chicane 29 in the product transfer chamber 56.Via the inlet chicane 29, which is shown in more detail in Figures 11 and 13, the product 4 passes through the filling gap 22 into the shaft 32, wherein the product preferably forms an angle of repose according to Figure 11 due to its pouring geometry, wherein Figure 11 shows different product heights which form different product surfaces 57, 57', 57'' and 57'''. The product surface 57-57''' can therefore vary within the indicated range, and the fill level is monitored by the fill level sensors 24b-24e shown in Figure 12. The feed of the powder material is adjusted depending on the fill level sensor 24b-24e. An upper fill level sensor 24a detects any overfilling of the product transfer chamber 56. If the fill level sensor 24a responds in this case, the distribution element 28 shown in Figure 1 would be activated.This is preferably a mechanical distribution element designed as a rake, fork or the like, which is movable in the plane of the drawing, namely in the direction of movement 50 in Figure 1. The fill level sensor 24a accordingly monitors any blockage and / or overfilling of the inlet chicane 29. Further details of the inlet chicane 29 are shown in Figure 12. The product falls in the direction of arrow 38 due to gravity over the discharge edge 61 at the outlet 8, forming a first parabola 66a into the product transfer space 56 of the storage container 9 and downwards onto the adjoining inlet chicane 29. The product initially reaches the first inclined impact surface 36 of the inlet chicane 29 and is then deflected in the direction of arrow 39 onto the opposite, further impact surface 37, arranged at the opposite angle, forming a second parabola 66b.The inlet chicane 29 therefore consists of two impact surfaces 36, 37 which are directed conically towards one another at an angle and follow one another in the direction of flow and which open into the inlet gap 22 beyond the discharge edge 61. Due to the fact that two opposing ultrasonic transmitters 21 are arranged at an angle to one another in the area of ​​the inlet chicane 29, optimal loosening of the product 4 is achieved in this area without the product bridging or sticking together in the area of ​​the inlet chicane 29. In a preferred embodiment of the invention, the discharge edge 61 is adjustable in the direction of arrow 53 relative to the storage container 9. This allows the immersion depth of the discharge edge 61 from the conveyor trough 5 into the product transfer space 56 to be changed in the direction of arrow 53 and thus the first throwing parabola 66a.The two impact surfaces 37, 38 form mutually inclined discharge surfaces, which form a second trajectory 66b for the discharged product. The trajectory 66b is adjusted such that when the product bounces off the impact surface 37, a third trajectory 66c is formed, which is adjusted so that the product runs centrally into the filling gap 22 below and is centered there. In this way, bridging and blockage in the filling gap 22 are reliably prevented. The angle that the two impact surfaces 36, 37 form to the vertical can be selected differently. The inclination of the impact surface 36 is preferably adjustable separately from the inclination of the adjacent impact surface 37. This allows the inclination and trajectory distance of the trajectories 66a and 66b to be adjusted.The parabolic path 66c results when the product strikes the right-hand impact surface 37, causing the product to enter the upper end of the filling gap 22 centrally and without jamming. The working area of ​​the impact surface 36 is dimensioned according to the maximum translational adjustment travel 60 (see Figure 10) that can occur during calender operation. The length of the impact surface 36 is dimensioned according to the maximum adjustment of the calender rolls that can occur during operation. This means that if the calender roll, to which the feed container 9 is translationally coupled, could be adjusted by 10 mm or 20 mm during operation, the area over which the parabolic path 66a strikes the impact surface 36 would be dimensioned accordingly. This ensures that the product first strikes the impact surface 36 and not immediately the impact surface 37.The product fill level must always be below the filling gap 22 in the area of ​​the fill level sensors 24b to 24e. Figures 15 to 20 show modified embodiments of the same dosing system 1, wherein the dosing system 1 is provided in the same way as described with reference to Figures 1 to 14. The same reference numerals apply to the same parts. Figures 15 and 16 show a double dosing system, 1, 1' with identical parts, as described above for a single dosing system 1, but additionally showing that a single- and / or double-sided coating of a current collector foil 54 takes place, which is located in the outer region between the two mutually associated calender rolls 14, 15.Figures 15 and 16 show the two-sided coating of the current collector foil 54, wherein the foil 4a emerging from the roll gap 12 of the calenders 14, 15 is bent over and laminated onto one side of the current collector foil 54 in the direction of the arrow 62. In the same way and analogously, the additional foil 4b is laminated onto the opposite side of the current collector foil 54 by the identical dosing system 1', wherein the current collector foil 54 is moved upward in the direction of the arrow 55. While Figures 15 and 16 show a two-sided coating of the current collector foil 54 with the product film 4a, 4b, Figure 17 shows a one-sided coating, wherein the same reference numerals apply to the same parts.In the embodiments as shown in Figures 15 to 18, the current collector foil 54 is moved upward in the direction of arrow 55, and during this movement, the one-sided or two-sided coating of the current collector foil with the product film 4a and / or 4b takes place in the direction of arrow 62. In the embodiments as shown in Figures 19 and 20, the current collector foil is moved downward. Figure 17 shows that the current collector foil 54 is also coated with the dry product film 4a from only one side. The invention is not limited to the arrangement of two opposing calender rolls 14, 15 or even not to two calender rolls 14, 15 that are present in two mutually assigned dosing systems 1, 1'. In the embodiments shown in Figures 18 to 20, it can be provided that more than two calender rolls are part of a dosing system 1 or 1'.In this case, the dry product film 4a leaving the first calender rolls 14, 15 is introduced into a nip 13' of another pair of calender rolls to achieve even further thinning of the product film. Accordingly, these are nips 13, 13' arranged one after the other, which successively thin the product film. This results in fibrillation of the material in the product film 4a, 4b. The dosing system 1, 1' according to the invention does not destroy or limit the fibrillation, but rather maintains it. Thus, the flowability of the powder is maintained to a maximum, because flowability decreases when exposed to heat. In a preferred embodiment of the invention, the shaft 32 is filled with a filling weight in the range of 500 g to 2,000 g, with a preferred size corresponding to a filling weight of approximately 1,000 g.The filling volume in the shaft 32, from the lower roll-gap-side outlet 23 to the upper fill level of the product surface 57, is preferably approximately 5 liters, although the volume can range between 2 and 10 liters. These specifications refer to a preferred calender width of 400 mm. For larger widths of the calender rolls 14, 15, the volume is correspondingly larger. The depth of the product transfer chamber 56 is preferably approximately 150 millimeters. The shaft 32 has a preferred height of approximately 500 mm. List of reference symbols 1. Dosing system for powder feed 1' Dosing system 2. Feed hopper 3. Direction of arrow 4. Product 4a Dry product film 4b Dry product film 5. Conveyor trough 6. Oscillating drive 7. Direction of arrow 8. Outlet 9. Feed hopper 10. Rear wall 10a Side wall 10b Adjustable side wall 11. Front wall 12. Accumulation area 13. Roller gap 13' 14. Calender roller 15. Calender roller 16. Direction of arrow 17. Further processing 18. Mill (fine dispersion) 19. Powder 20.Binder 21. Ultrasonic transducer / vibrator 21a-21d 22. Inlet gap (of 9) 23. Outlet gap (of 9) 24. Level sensor 24a-24e 25. Extension (of 10a) = Spickel 65 26. Suction nozzle 27. Intake nozzle 28. Distributor 29. Inlet baffle 30. Heat sink 31. Sealing sleeve 32. Shaft 33. Direction of arrow 34. Direction of arrow 35. Guide surface 36. Baffle surface 37. Baffle surface 38. Direction of arrow 39. Direction of arrow 40. Direction of arrow (for 26) 41. Direction of arrow (air extraction) 42. Filter 43. Fan 44. Filter 45. Direction of arrow 46. Flexible connection 47. Duct extension 48. Inlet area 49. Discharge area 50. Direction of movement (of 28) 51. Direction of oscillation 52. Motor 53. Direction of adjustment 54. Current collector foil 55. Direction of arrow 56. Product transfer space 57. Product surface 57', 57'', 57''' 58. Bracket 59. Distance 60. Direction of arrow 61. Discharge edge 62. Direction of arrow 63. Radius (of 25) 64. Wing 65. Spigot = extension 25 66. Throw parabola 66a, 66b, 66c.

Claims

AMENDED CLAIMS received by the International Bureau on 18 September 2024 (18.09.2024) 1. Dosing system for dry coating battery electrodes with a powdered product (4) which is fed in a continuous product stream onto the roller gap (13) between two calender rollers (14, 15), wherein a storage container (9) for receiving the product (4) is arranged upstream of the roller gap (13) and is fed via a conveyor trough (5), wherein the lower part of the storage container (9) forms a shaft (32) in which at least two opposite walls (10, 10a, 11) are designed to diverge uniformly conically from an upper inlet gap (22) in the direction of an outlet gap (23) opposite the roller gap (13), characterized in that a constant fill level is provided in the shaft (32) by means of a fill level sensor (24) and / or control of the feed (6, 18).

2. Dosing system according to claim 1, characterized in that the front wall (11) in conjunction with the opposite rear wall (10) form the conically diverging shaft (32) and that the side walls (10a, 10b) are parallel to each other.

3. Dosing system according to claim 1, characterized in that the front wall (11) in conjunction with the opposite rear wall (10) form the conically diverging shaft (32) and that the side walls (10a, 10b) are also conically diverging from one another.

4. Dosing system according to claim 1, characterized in that the Front wall (11) in connection with the opposite rear wall (10) are parallel to each other and that the side walls (10a, 10b) are conically diverging from each other. 5, Dosing system according to at least one of claims 1 to 4, characterized in that the width of the outlet gap of the storage container (9) is 80% smaller than the length of the calender rolls, but preferably 10 mm narrower than the target width of the dry film (4a).

6. Dosing system according to at least one of claims 1 to 5, characterized in that the depth of the shaft (32) is in the range between 10 to 20 mm with a preferred height of 500 mm with a range of 100 to 1000 mm.

7. Dosing system according to at least one of claims 1 to 5, characterized in that the powdered product (4) is mixed and finely dispersed in a mill (18) arranged on the inlet side or a pneumatic conveying system and then falls due to gravity into a feed hopper (2) which feeds a conveyor trough (5) conveying in the horizontal direction.

8. Dosing system according to claim 7, characterized in that the conveyor trough (5) is driven by a vibration drive (6, 52) obliquely to the conveying direction.

9. Dosing system according to at least one of claims 1 to 8, characterized in that in a lower region of the storage container (9) a storage area (12) for the product (4) is arranged, which extends from the interior of the shaft (32) to the nip (13) of the calender rolls (14, 15).

10. Dosing system according to at least one of claims 1 to 9, characterized in that the outlet gap (23) of the shaft (32) projects into the roller gap (13).

11. Dosing system according to at least one of claims 1 to 10, characterized in that the side walls (10a) have lateral extensions (.25) which project beyond the outlet gap (23).

12. Dosing system according to at least one of claims 1 to 11, characterized in that the storage container (9) is designed to be raised and / or lowered in the vertical direction from the roller gap (13).

13. Dosing system according to at least one of claims 1 to 12, characterized in that the opposite side walls (10a, 10b) form guide surfaces (35) in contact with the product between them, and that the respective guide surface (35) is designed either as a straight line or as a convex curvature.

14. Dosing system for the dry coating of battery electrodes with a powdery product (4) which is fed in a continuous product stream onto the roll gap (13) between two calender rolls (14, 15), wherein a feed container (9) receiving the product (4) is arranged upstream of the roll gap (13) and is fed via a conveyor trough (5), wherein the lower part of the feed container (9) forms a shaft (32), characterized in that an inlet side of the shaft (32) is formed by an inlet chicane (29) via which the product (4) is uniformly introduced, wherein the inlet chicane (29) consists of at least two impact surfaces (36, 37) arranged one behind the other in the direction of flow and arranged at opposite angles to one another.

15. Dosing system according to claim 14, characterized in that the at least two impact surfaces (36, 37) are individually and / or jointly adjustable in their inclination to the vertical.

16. Dosing system according to at least one of claims 14 or 15, characterized in that in order to form an adjustable first throwing parabola (66a) for the product (4) falling onto the first blasting surface (36), the immersion depth of a discharge edge (61) of the conveyor trough (5) into the product transfer space (56) is adjustable.

17. Dosing system according to at least one of claims 14 to 16, characterized in that a second adjustable parabola (66b) in the transition from the first impact surface (36) onto the second impact surface (37), and that a third adjustable parabola (66c) is present from the second impact surface (37) onto the center of the filling gap (22).

18. Dosing system according to at least one of claims 14 to 17, characterized in that the inlet chicane (29) is conically tapered and offset in height and allows a movement of the storage container (9) towards the conveyor trough (5).

19. Dosing system according to at least one of claims 1 to 18, characterized in that an intake and exhaust nozzle (26, 27) is provided for generating a negative pressure in the storage container (9).

20. Dosing system according to at least one of claims 1 to 19, characterized in that a dust-tight connection between the conveyor trough (5) and the storage container (9) is provided by an elastically deformable seal (31), which largely prevents the transmission of vibrations from the conveyor trough (5) to the storage container (9) 21. Dosing system according to at least one of claims 14 to 20, characterized in that a filter (42) for sucking outside air into the interior of the storage container (9) is arranged in an upper region of the product transfer space (56) above the inlet chicane (29).

22. Method for dosing powder material for dry coating battery electrodes with a powdery product (4) which is fed in a continuous product stream onto the roller gap (13) between two calender rollers (14, 15), wherein a storage container (9) receiving the product (4) is arranged in front of the roller gap (13), which storage container is fed via a conveyor trough (5), wherein the lower part of the storage container (9) forms a shaft (32), characterized in that an inlet side of the shaft (32) is formed by an inlet chicane (29) over which the product flows and is loosened in the process, wherein the inlet chicane (29) consists of at least two in the flow direction one behind the other arranged and arranged at opposite angles to each other.

23. Method according to claim 22, characterized in that the product transfer space (56) above the inlet chicane (29) in the storage container (9) is flushed with filtered fresh air.

24. A method for operating a dosing system for dosing powder material for dry coating battery electrodes with a powdery product (4) which is fed in a continuous product stream onto the roller gap (13) between two calender rollers (14, 15), wherein a storage container (9) receiving the product (4) is arranged upstream of the roller gap (13) and is fed via a conveyor trough (5), wherein the lower part of the storage container (9) forms a shaft (32) in which at least two opposite walls (10, 10a, 11) are designed to diverge uniformly conically from an upper inlet gap (22) in the direction of an outlet gap (23) opposite the roller gap (13), characterized in that the inlet gap (22) of the storage container (9) arranged at the outlet (8) of the conveyor trough (5) is fed uniformly via an inlet chicane (29). over which the product (4) flows and is loosened,wherein the inlet chicane (29) consists of at least two impact surfaces (36, 37) arranged one behind the other in the direction of flow and arranged at opposite angles to each other,