Method and apparatus for producing electrode for rechargeable battery

Abstract

To provide a method and an apparatus for efficiently producing an electrode for a rechargeable battery that enable uniform application of an electrode material onto a carrier while minimizing the use of harmful solvents as much as possible.SOLUTION: The invention relates to a method for producing an electrode for a rechargeable battery, where an electrode compound is applied to a carrier, in particular metal foil, by means of an extrusion step. In the extrusion step, the electrode compound is fed through an extrusion die by means of a feeding device. The electrode compound is prepared by mixing in a mixing device and passed on from the mixing device to the feeding device, fluctuations in the flow rate of the electrode compound that is passed on from the mixing device to the feeding device being evened out.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a method and an apparatus for manufacturing an electrode for a rechargeable battery according to the preamble of the independent claim.

Background Art

[0002] Common to this type of method is that, in order to manufacture the electrode, first the electrode material is applied to a carrier. This application of the electrode material is then further processed by downstream method steps, in particular drying steps, extraction steps, and / or steps for introducing a suitable electrolyte, depending on how the subsequent method proceeds, to form the electrode. The electrode material may consist of a plurality of components. Here, the application of the electrode material to the carrier is not a trivial step, but a step that is relevant to the quality of the resulting rechargeable battery. In the finished rechargeable battery, the carrier, which can in particular be a metal foil, is often wound up, folded and / or laminated into a plurality of layers. Therefore, the thin layer of electrode material must be applied with high uniformity.

[0003] On an industrial scale, this is carried out by means of the so-called "wet process". The wet process includes the step of mixing substances that already have a very low viscosity at a relatively low temperature. The substance is then applied to the carrier at room temperature, generally by means of a slot die.

[0004] The drawback of these methods is that the required viscosity of the substance to be applied is established by the solvent. The solvent can be, for example, N-methyl-2-pyrrolidone (NMP). The substance thus obtained, known as a slurry, has excellent properties for application to the carrier, but then the solvent has to be removed from the electrode material. The use of the solvent causes environmental and health risks, which is undesirable. Therefore, especially against the backdrop of ever more stringent environmental regulations, it is desirable to find a way to eliminate or at least reduce the need to use such harmful solvents.

[0005] Therefore, for example, Patent Document 1 (DE102004012476A1) discloses a method in which an electrode material is manufactured and applied to a carrier using a flow promoter at high temperature without using a solvent to the maximum extent possible. This method is carried out by using a so-called twin-screw extruder. This extruder can be heated. This extruder has a very high shear rate. As a result, this extruder can achieve sufficient mixing even with a relatively highly viscous material. Therefore, when the components of the electrode material are supplied to this extruder, such a twin-screw extruder first processes those components into a sufficiently homogeneous mixture and then supplies this material through an extrusion die that can also be heated, whereby this material can be applied to the carrier.

[0006] However, in practice, it has been found that the mass flow of the electrode material sent by the twin-screw extruder varies over time. This is due to the type of structure of the twin-screw extruder that acts as a mixing and feeding device in this process. When applying the electrode material to the carrier, the lack of uniformity caused by this variation has so far prevented the application of this method on an industrial scale.

[0007] Similarly, Patent Document 2 (EP2744019A1) discloses a method for manufacturing an electrode that minimizes the use of harmful solvents as much as possible. However, in this method, first, a molding material in the form of extruded pellets is produced. In a further method step, these pellets are melted at a later time and applied to the carrier by extrusion. Carrying out the method in this way is inefficient. On the one hand, the energy consumption increases by repeatedly melting the electrode material. On the other hand, by separating the production of the pellets in which the electrode material is mixed and the subsequent application of the electrode material to the carrier, additional labor is involved in handling the pellets between the two method steps.

Prior Art Documents

Patent Documents

[0008]

Patent Document 1

Patent Document 2

Summary of the Invention

[0009] Accordingly, the present invention is based on the object of providing a method and an apparatus for manufacturing an electrode for a rechargeable battery that can uniformly apply an electrode material to a carrier without using harmful solvents as much as possible and is more efficient.

[0010] This object is achieved by a method and an apparatus having the features of the independent claims. The features of the dependent claims relate to advantageous embodiments.

[0011] A method for manufacturing an electrode for a rechargeable battery includes first mixing an electrode material in a mixing device and sending it by the mixing device to a supply device. In this case, the mixing device and / or the supply device operate continuously in particular. Sending the mass flow of the electrode material from the mixing device to the supply device is done continuously in particular. In this case, fluctuations in the mass flow of the electrode material sent to the supply device by the mixing device are compensated for. By sending the mass flow of the electrode material from the mixing device to the supply device, the method can be carried out without interruption. This, on the one hand, results in the efficiency of this method being more efficient as storage is no longer necessary and the handling effort is reduced compared to the "wet method" described in the prior art where the production of the "slurry" is carried out batchwise, thus discontinuously, and an implementation method where intermediate products such as pellets mentioned at the beginning are produced first. On the other hand, it has the advantage that certain characteristics, in particular a certain quality, can be ensured more appropriately.

[0012] By implementing the method in this way, the process step of mixing the electrode material and the process step of supplying it via an extrusion die can be separated from each other. As a result, the supply device can be optimized to supply a mass flow that is as constant as possible via the extrusion die. This leads to the electrode material being uniformly applied to the carrier accordingly.

[0013] Correspondingly, the presented and described device has a compensation device for compensating fluctuations in the mass flow of the electrode material produced by the mixing device and sent to the supply device.

[0014] By separating the function of "mixing electrode materials" and the function of "supplying electrode materials through an extrusion die" into different directional steps or different technical devices, the effect that each device or each method step can be optimized with respect to the effect to be achieved is achieved. The mixing of electrode materials or the mixing device can be optimized with respect to mixing the components as well as possible and, correspondingly, with respect to the resulting homogeneous electrode material. On the other hand, the supply of electrode materials through an extrusion die or the supply device used therefor can be optimized with respect to making the mass flow of the supplied electrode material as constant as possible. The extrusion die can in particular be a slot die.

[0015] Thus, in order to compensate for fluctuations, the electrode material may be stored in the middle. For this purpose, the device may have, for example, an intermediate storage device. The intermediate storage device may be, for example, a compensation container. In particular, the intermediate storage device enables the mixing device to supply a mass flow that varies over time to the intermediate storage device, while at the same time the supply device receives a constant mass flow that has at least less fluctuations than the mass flow generated by the mixing device. Therefore, the fluctuations in the mass flow sent by the mixing device are compensated by the corresponding fluctuations in the filling level of the intermediate storage device. Here, it has been found that in practice the intermediate storage device may be made relatively small. This is always the case especially when the fluctuations in the overall mass flow of the electrode material sent by the mixing device are small and / or these fluctuations occur regularly, especially periodically. Both of these cases always apply, for example, when the mixing device is a twin-screw extruder.

[0016] Alternatively and / or additionally, in order to compensate for the fluctuations in the mass flow of the electrode material sent by the mixing device, the electrode material may be returned to the mixing device. For the device, this means in particular that the device has a return device for returning the electrode material to the mixing device.

[0017] This, in particular, has the effect that from the variable mass flow of the electrode material sent by the mixing device, a part of the flow branches off. This part of the flow is returned to the mixing device, where it is mixed with the starting material of the electrode material. In particular, if the mixing ratio of each component is kept constant over time, the returned electrode material does not change the quality, in particular the composition, of the produced mixture. In this case, the returned part of the flow of the electrode material has corresponding fluctuations resulting from the fluctuations of the mass flow of the electrode material sent by the mixing device. Correspondingly, the remainder of the mass flow of the electrode material sent by the mixing device becomes fluctuation-free or at least less fluctuating than the mass flow sent by the mixing device. Thus, the supply device can receive a constant mass flow of the electrode material, or at least a more constant mass flow than the mass flow sent by the mixing device.

[0018] Incidentally, it is particularly preferred if the mixing device and the supply device are designed and / or operate in such a way that the mixing device sends a mass flow of the electrode material that is more than the amount received by the supply device. This difference makes it possible to branch off the part of the flow that needs to be returned.

[0019] Needless to say, the two concepts presented above for providing compensation and compensation devices may be implemented in the same method or the same device. This means that this method may provide both the intermediate storage of the electrode material between mixing and supply via an extrusion die and, at the same time, the return of the electrode material. Correspondingly, the device may have both a return device and an intermediate storage device arranged between the mixing device and the supply device. Arranging between the supply device and the mixing device does not necessarily mean here the spatial arrangement of the devices relative to each other, but rather the arrangement along the flow path of the electrode material.

[0020] The method may in particular comprise applying an electrode material to a carrier in the form of an uninterrupted strip extending in the application direction and having a length of at least 2 m, in particular at least 5 m. Compensating for fluctuations in the mass flow of the electrode material fed to the supply device by the mixing device has the effect, in particular, that the electrode material can be applied evenly even to such a long strip. The evenness of the application here in particular corresponds to forming the edges of the electrode material extending parallel to the application direction as straight as possible. Incidentally, the application direction should be understood in particular to mean the direction in which the carrier is moved past the extrusion die while the electrode material is being applied. The relative movement has the effect that the strip of electrode material accumulates on the carrier in this application direction.

[0021] The method may in particular comprise applying an electrode material to a carrier such that a strip without electrode material, extending parallel to the application direction of the electrode material, is formed on the carrier along the electrode material. Such a strip without electrode material may for example function for the electrical contact of each electrode. Incidentally, it is particularly important that the edges of the electrode material extending parallel to the application direction are clearly defined and as straight as possible. Only in this way is it ensured that a clearly defined strip without electrode material is formed on the carrier.

[0022] The device may have a measuring device for measuring measurement variables regarding the electrode material sent to the supply device by the mixing device. Correspondingly, the method may include that measurement variables regarding the electrode material sent to the supply device by the mixing device are measured. The measurement variables can in particular be the filling level of the intermediate storage device and / or the mass flow of the electrode material returned by the return device. As a result, in particular, information can be obtained regarding the extent to which the relationship between the mixing device and the supply device is adjusted to each other with respect to the mass flow of the electrode material processed in each case, in particular, regarding the extent to which a continuous and continuous operation is possible, and / or regarding whether the electrode material is accumulating or lacking in the intermediate storage device or in the circuit formed by the return. This is always the case, in particular, when the mass flows sent by the mixing device and / or received by the supply device are not adjusted to each other with sufficient certainty.

[0023] Regarding the method described herein and the device described herein, in particular with regard to the measurements described above, the mass flow is not necessarily understood to mean that the actual (molar) amount of the substance is recorded or measured. Rather, the mass flow should be understood to mean the mass flow in the broadest sense, that is, in particular, the mass flow represented by appropriate representative variables, for example the mass flow and / or volume flow as the actually used measurement variables and / or control variables.

[0024] In particular, the device may be controlled in response to the measured variable. For this purpose, the device may have a closed-loop and / or open-loop control device configured accordingly. This may include closed-loop control, which functions in particular to maintain a steady state in continuous operation. In particular, for this purpose, the closed-loop and / or open-loop control device may function to perform closed-loop and / or open-loop control of a metering device for metering the components of the electrode material. Incidentally, the metering device may be suitable for metering a plurality of components, or there may be a plurality of metering devices. The metering device functions in particular to feed one or more components of the electrode material to a mixing device. Such a metering device may primarily function to set the quantity ratio of the individual components of the electrode material. However, further, the mass flow of the total quantity of the plurality of components fed to the mixing device may also be controlled in an open-loop and / or closed-loop manner. Thus, in combination with the above-described measurement or measuring device, it is possible to ensure that the filling level of the intermediate storage device and / or the mass flow of the electrode material returned by the return device vary within a tolerance range particularly suitable for stable, continuous and ongoing operation.

[0025] In particular, the method may include keeping the electrode material in a fluid state between exiting the mixing device and entering the supply device. This particularly applies to the period during which the electrode material is stored intermediate or at the point in time when a part of its flow is branched off to return the electrode material to the mixing device. By keeping the material in a fluid state, it becomes possible to perform this step stably and continuously.

[0026] The method may include degassing the electrode material. This can be desirable especially to ensure that no gas is contained in the electrode material after it has been applied to the carrier. Such gas containment can occur, for example, during the mixing of the components of the electrode material. Similarly, gas containment can occur due to the evaporation of impurities. These impurities can be, for example, water. Degassing may already be carried out especially during the mixing of the components of the electrode material and / or during the intermediate storage of the electrode material.

[0027] In particular, the method includes that the temperature of the electrode material, from exiting the mixing device until entering the supply device, is always at least 80 °C, in particular at least 90 °C, and / or at most 160 °C, in particular at most 120 °C. This relates in particular to the temperature of the electrode material during intermediate storage and / or the temperature of the electrode material in a partial flow branch for returning to the mixing device.

[0028] In particular, the method includes that the temperature of the electrode material in the mixing device is at least 80 °C, in particular at least 90 °C, and / or at most 140 °C, in particular at most 120 °C.

[0029] In particular, the method includes that the temperature of the electrode material in the supply device and / or in the extrusion die is at least 80 °C, in particular at least 90 °C, and / or at most 150 °C, in particular at most 130 °C.

[0030] Within these temperature ranges, it has been found that appropriate rheological properties can be achieved, in particular keeping the electrode material in a fluid state.

[0031] The device may have a heating device. Here, the heating device particularly serves to heat the mixing device, the compensating device, the supply device, and / or the extrusion die. The heating device enables the electrode material to be kept in a fluid state particularly from when the electrode material is mixed in the mixing device until it exits the extrusion die. Correspondingly, the heating of the electrode material realized by this method is particularly carried out from when the electrode material is mixed until it exits the extrusion die.

[0032] This mixing device, which particularly operates continuously, can be a multi - screw extruder. Since the multi - screw extruder generates a high shear rate in the material supplied through it, it has very good characteristics regarding the mixing of viscous or paste - like materials. Thus, when multi - screw extruders are used as the mixing device, they bring about a very good homogeneity of the produced electrode material. Incidentally, it has been proven that it is particularly advantageous if the mixing device is a twin - screw extruder.

[0033] The supply device is particularly a positive - displacement pump. The positive - displacement pump is particularly advantageous for supplying a relatively viscous medium. In particular, the supply device may be a gear pump. It is known that the gear pump can particularly generate a very consistent mass flow.

[0034] Particularly, due to the dominance of the shear force in the extrusion die, the rheological properties of the electrode material are selected in accordance with the characteristics of the method and / or the device such that the electrode material in the extrusion die has fluidity, loses this fluidity as soon as it exits the extrusion die, and subsequently, as a result, the shear force disappears. This has a favorable effect on the electrode material that maintains a cross - section predetermined by the shape of the extrusion die when the electrode material is applied to the carrier.

[0035] The electrode material may have a main agent and a plasticizer as basic components. In this case, in particular, the main agent contains components for forming an electrode after at least partially removing the plasticizer later. The electrode material, especially the main agent, has an active material as a component. The active material may be, in particular, graphite in the case of a negative electrode, and / or in the case of a positive electrode, lithium nickel manganese cobalt oxide, lithium nickel cobalt aluminum oxide, or lithium iron phosphate (LiFePO₄). Other active materials, especially lithium compounds, are also conceivable. What is called an active material is a chemically active substance in the electrode responsible for energy storage, where these active substances undergo chemical changes including the release and / or accumulation of charge carriers when the rechargeable battery is charged and / or discharged.

[0036] The mass ratio of the active material in the main agent is at least 88% and / or at most 97%.

[0037] The electrode material, especially the main agent, may also contain an additive for improving conductivity. This additive can be, for example, carbon black and / or graphite. The mass ratio of the additive in the main agent is at least 1.5% and / or at most 5%.

[0038] The electrode material, especially the main agent, may contain a binder. The binder may be a polymer, especially a fluoropolymer. The mass ratio of the binder in the main agent may be at least 1.5%, especially at least 3%, and / or at most 7%, especially at most 5%.

[0039] The electrode material may also contain a plasticizer. The plasticizer can be, for example, a substance having suitable phase transition behavior. This should be understood to mean in particular a substance with a melting point of at most 80 °C, especially at most 35 °C, and / or a boiling point of at least 120 °C, especially at least 140 °C. Substances having such phase transition behavior are suitable for keeping the electrode material in a plastic or fluid state during mixing or during supply to the extrusion die. At the same time, they are also suitable for reliably forming a stable layer on the carrier immediately after exiting the extrusion die, without the risk of forming gas during method steps carried out especially at high temperatures.

[0040] The mass ratio of the plasticizer may in particular be selected according to the properties of the components of the main agent. Parameters such as the particle size, surface size, as well as the amount and type of additional substances such as binders and / or additives for improving conductivity may be considered here. Similarly, the amount and type of the active material also have an impact. Incidentally, when using graphite as the active material for the negative electrode, it has been proven advantageous if the mass ratio of the plasticizer is at least 14%, especially at least 20%, and / or at most 42%, especially at most 40%. In the case of the positive electrode, especially in the case of a lithium iron phosphate positive electrode, the ratio of the plasticizer can be at least 30%, especially at least 35%, and / or at most 50%, especially at most 42%.

[0041] In particular, the plasticizer can be ethylene carbonate. According to the prior art, ethylene carbonate has already been used in the electrolyte of rechargeable batteries of this type, and thus it does not pose a problem for rechargeable batteries, especially for the way the rechargeable battery functions. Furthermore, due to the position of the melting point, ethylene carbonate has a temperature-dependent behavior, whereby ethylene carbonate acts as a plasticizer at the temperature prevailing between the mixing device and the extrusion die, and after the electrode material has been cooled on the carrier, especially after being cooled to room temperature, it is possible to at least considerably reduce its effect as a plasticizer.

[0042] The method may include cooling the electrode material after it has been applied to the carrier. This may in particular include cooling to room temperature.

[0043] The carrier can in particular be a metal foil. The metal foil in particular has the shape of an elongated strip. While the electrode material is being applied to the carrier, the metal foil is in particular moved through an extrusion die. The metal can in particular be copper and / or aluminum. The carrier may in particular be stored on a roller from which the carrier is unwound and conveyed towards the extrusion die.

[0044] A measuring device may be present for recording the amount of electrode material applied to the carrier. This may in particular be a measuring device for measuring the thickness of the electrode material applied to the carrier. In particular, the measuring device may be a so-called "beta gauge". This is a measuring device for measuring thickness by means of radiation, which measures the thickness of a transradiated layer based on beta rays. However, in principle, other thickness measurement methods, in particular other radiation-based thickness measurement methods, are also conceivable.

[0045] The apparatus may have a control device configured to control the apparatus, in particular the supply device, in response to the measurement values recorded by the measuring device. As a result, fluctuations in the mass flow of the electrode material can be further reduced.

[0046] The method may include removing the plasticizer from the electrode material, at least to a significant extent. This may in particular include forming pores in the electrode. The removal of the plasticizer may in particular be effected by the action of heat. For this purpose, the apparatus may in particular have a heating device. This heating device can for example be an infrared heating device. In this case, the action of heat may in particular have the effect that the plasticizer evaporates.

[0047] The plasticizer can be reused. This can be done, for example, if the plasticizer has already evaporated, by removing the plasticizer by means of a gas stream, condensing it and removing it from the gas stream. The gas stream can in particular be an air stream.

[0048] According to the method described above, it is possible to apply the electrode material on both sides of the carrier material.

[0049] Further practical embodiments and advantages of the present invention will be described below with reference to the drawings.

Brief Description of the Drawings

[0050]

Figure 1

Figure 2

Figure 3

Mode for Carrying Out the Invention

[0051] The apparatus 10 provided as an example is suitable for and intended to implement a method in which an electrode material 12 is applied to a carrier 14. The carrier 14 can be in the form of a strip, wound up, as in the example presented. Correspondingly, the apparatus 10 may have a feeding device 16 for feeding out the carrier 14.

[0052] The electrode material 12 is applied to the carrier 14 by means of an extrusion die 18. For this purpose, the electrode material 12 is supplied by a supply device 20 via the extrusion die 18. Although only schematically illustrated in the example shown, the supply device 20 may be a gear pump. The carrier 14 is in this case moved in the application direction 44 so as to pass through the extrusion die 18.

[0053] The device 10 also has a mixing device 22. Although only schematically illustrated in the example shown, the mixing device 22 may be formed as a twin-screw extruder. The mixing device 22 mixes the electrode material 12, and then this electrode material 12 is sent by the mixing device 22 to the supply device 20. In this case, fluctuations in the mass flow of the electrode material 12 sent from the mixing device 22 to the supply device 20 are compensated by the compensation device 24. In the example shown, the compensation device 24 can be an intermediate storage device. The compensation device 24 can store a part of the mass flow of the electrode material 12 sent from the mixing device 22 to the supply device 20 in the middle. The fluctuations in the mass flow are, so to speak, "smoothed".

[0054] As in the example shown, the device 10 may have a plurality of metering devices 26, 28 for metering the various components of the electrode material 12. Similarly, the device 10 may have a metering device 30 for metering the plasticizer. Using the metering devices 26, 28, 30, the corresponding components can be metered each time and put into the mixing device 22, that is, in particular, it is possible to control the mass flow in an open-loop and / or closed-loop manner. Incidentally, the device 10 may have a closed-loop and / or open-loop control 32 that is specifically designed to control the mass flow sent to the mixing device 22 by the metering devices 26, 28, 30 according to the measuring device, and the measuring device is not shown more specifically here. The measuring device not shown more specifically can be, in particular, a measuring device for measuring the filling level in the intermediate storage device.

[0055] The mixing device 22, the compensation device 24, the supply device 20, and / or the extrusion die 18 may each have a heating device 34. In particular, the mixing device 22 may have a plurality of heating devices 34, as shown in the case of the device 10 provided as an example. In this way, for example, different heating zones can be realized.

[0056] Similar to the case of the device 10 presented as an example, immediately after the electrode material 12 is applied to the carrier 14, the carrier 14 may be supplied to the cooling device 36. Incidentally, the change from FIG. 1 to FIG. 2 is for merely practical representation reasons. In fact, the composite material including the carrier 14 and the electrode material 12 formed by the application is directly continued and further conveyed between the partial devices 10 shown in FIGS. 1 and 2.

[0057] As presented in the example, the thus-formed composite material including the carrier 14 and the electrode material 12 may be supplied to the layer thickness measuring device 38. The results of the layer thickness measurement, particularly the results of the layer thickness measurement of the layer of the electrode material 12, may likewise be used for the closed-loop and / or open-loop control of the device 10, particularly the metering devices 26, 28, and / or 30.

[0058] As in the presented example, the device 10 may have a heating device 40. This heating device 40 can be, for example, an infrared oven. This heating device particularly functions to remove at least partially the plasticizer from the electrode material 12. Also, this heating device 40 particularly has the effect of creating pores into which an electrolyte can penetrate at a later point in time.

[0059] As shown in the example, the device 10 may have a winding device 42 for winding an electrode formed by a composite material including the carrier 14 and the layer of the electrode material 12 applied thereto.

[0060] FIG. 3 shows a portion of the carrier 14 to which a strip of the electrode material 12 is applied. The strip of the electrode material 12 extends parallel to the application direction 44. A strip 46 without the electrode material also extends parallel to the strip of the electrode material 12 and the application direction 44. As a result of compensating for the fluctuations of the mass flow sent to the supply device by the mixing device, the edge 48 is particularly straight and regularly formed.

[0061] According to the first example, the electrode material for the positive electrode to be mixed in the hybrid device can be a mixture of a main agent and a plasticizer. The mass ratio of the plasticizer in this mixture can be, for example, 24%. The plasticizer can be ethylene carbonate. Each of the main agents may contain two different binders in mass ratios of 4% and 2% with respect to the main agent, may contain graphite and carbon black in mass ratios of 3% each as additives for enhancing conductivity, and may contain lithium nickel cobalt aluminum oxide in a mass ratio of 88% as the active material.

[0062] According to the second example, the electrode material for the positive electrode to be mixed in the hybrid device can be a mixture of a main agent and a plasticizer. The mass ratio of the plasticizer in this mixture can be, for example, 35%. The plasticizer can be ethylene carbonate. Each of the main agents may contain a binder in a mass ratio of 7% with respect to the main agent, may contain carbon black in a mass ratio of 5% as an additive for enhancing conductivity, and may contain lithium iron phosphate in a mass ratio of 88% as the active material.

[0063] According to the third example, the electrode material for the negative electrode to be mixed in the hybrid device can be a mixture of a main agent and a plasticizer. The mass ratio of the plasticizer in this mixture can be, for example, 38%. The plasticizer can be ethylene carbonate. Each of the main agents may contain a binder in a mass ratio of 6.5% with respect to the main agent, may contain carbon black in a mass ratio of 4.5% as an additive for enhancing conductivity, and may contain graphite in a mass ratio of 89% as the active material.

[0064] The features of the present invention disclosed in this specification, the drawings, and the claims may be fundamental for implementing the present invention in its various embodiments individually and in any desired combination. The present invention is not limited to the described embodiments. The present invention can be modified within the scope described in the claims in consideration of the knowledge of those skilled in the art.

Description of Reference Numerals

[0065] 10 Device 12 Electrode Material 14 Carrier 16 Pay-Out Device 18 Extrusion Die 20 Supply Device 22 Mixing Device 24 Compensation Device 26 Metering Device 28 Metering Device 30 Metering Device 32 Closed Loop / Open Loop Control 34 Heating Device 36 Cooling Device 38 Layer Thickness Measuring Device 40 Heating Device 42 Take-Up Device 44 Coating Direction 46 Strip Without Electrode Material 48 Edge

Claims

1. A method for manufacturing an electrode for a rechargeable battery, wherein an electrode material (12) is applied to a carrier (14), in particular a metal foil, by an extrusion process, and in the course of said extrusion process, the electrode material (12) is supplied by a supply device (20) via an extrusion die (18), characterized in that the electrode material (12) is mixed in a mixing device (22) and sent to the supply device (20) by the mixing device (22), a variation in the mass flow of the electrode material (12) sent to the supply device (20) by the mixing device (22) is compensated for.

2. The method according to claim 1, characterized in that the electrode material (12) is stored intermediate in order to compensate for said variation.

3. The method according to claim 1 or 2, characterized in that the electrode material (12) is returned to the mixing device (22) in order to compensate for said variation.

4. The method according to any one of claims 1 to 3, characterized in that the electrode material (12) is applied to the carrier (14) in the form of an uninterrupted strip having a length of at least 2 m, in particular at least 5 m, extending in the application direction (44).

5. The method according to any one of claims 1 to 4, characterized in that the electrode material (12) is applied to the carrier (14) such that a strip (46) without electrode material, extending parallel to the application direction of the electrode material, is formed on the carrier (14) along the electrode material (12).

6. The method according to any one of claims 1 to 5, characterized in that the electrode material (12) is kept in a fluid state, in particular during intermediate storage, from leaving the mixing device (22) until entering the supply device (20).

7. The method according to any one of claims 1 to 6, characterized in that the temperature of the electrode material (12) from leaving the mixing device (22) until entering the supply device (20), in particular during intermediate storage, is always at least 80°C, in particular at least 90°C, and / or at most 140°C, in particular at most 120°C.

8. The method according to any one of claims 1 to 7, characterized in that the electrode material (12) has ethylene carbonate as a plasticizer.

9. An apparatus (10) for manufacturing an electrode for a rechargeable battery, in particular by the method according to any one of claims 1 to 8, the apparatus having a mixing device (20) for mixing an electrode material (12) and a supply device (20) for supplying the electrode material (12) via an extrusion die (18). The apparatus is characterized by having a compensation device (24) for compensating fluctuations in the mass flow of the electrode material (12) produced by the mixing device (22) and sent to the supply device (20).

10. The apparatus according to claim 9, characterized in that the apparatus (10), in particular the compensation device (24) and the intermediate storage device, have a compensation container for compensating the fluctuations.

11. The apparatus according to claim 9 or 10, characterized in that the apparatus (10), in particular the compensation device (24) for compensating the fluctuations, has a return device for returning the electrode material (12) to the mixing device (22).

12. The apparatus according to any one of claims 9 to 11, characterized in that the mixing device (22) is a multi-axis extruder, in particular a twin-screw extruder.

13. The apparatus according to any one of claims 9 to 12, characterized in that the supply device (20) is a positive displacement pump, in particular a gear pump.

14. The apparatus according to any one of claims 9 to 13, characterized by having a measuring device (38) for measuring a measured variable related to the electrode material (12) sent by the mixing device (22) to the supply device (20), in particular for measuring the filling level of the intermediate storage device and / or for measuring the mass flow returned by the return device.

15. The apparatus according to claim 14, characterized in that the apparatus (10), in particular a metering device (26, 28, 30) for metering the components of the electrode material (12), has a closed-loop and / or open-loop control device (32) for controlling according to the measured variable.

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