Method for separating an electrode material

Abstract

Method for separating an electrode material (2), in particular a cathode material, comprising a carrier film (3) and an active material (4) applied to the carrier film (3) by means of a binder material (5), characterized in that the electrode material (2), in particular comminuted, is fed to an impact mill (6) and the active material (4) is separated from the carrier film (3) in the impact mill (6), wherein the electrode material (2) is temperature-controlled for the separation of the active material (4).

Description

[0001] The invention relates to a method for separating an electrode material, in particular a cathode material, comprising a carrier film and an active material applied to the carrier film by means of a binder material.

[0002] Methods for separating electrode material, specifically cathode material, are known in the art, for example, for recycling, i.e., reusing components of the electrode material. Particularly in so-called "direct recycling," it is necessary to separate the electrode material into its components in order to improve the reuse of the individual components. Typically, the electrode material is separated by separating the carrier film and the active material applied to the carrier film by means of a binder, so that the individual components can then be reused separately.

[0003] In addition to approaches that involve reuse via pyro-recycling or hydro-recycling, "direct recycling" can also involve the mechanical separation of the active material and the carrier film. The aim here is to achieve the most efficient separation process possible, for example, to perform the mechanical separation as quickly as possible while ensuring the safe separation of the electrode material components.

[0004] The invention is based on the objective of providing an improved method for separating an electrode material, in which, in particular, the separation of the active material and the carrier film is improved.

[0005] The problem is solved by a method with the features of claim 1. Advantageous embodiments are the subject of the dependent claims.

[0006] As described, the invention relates to a method for separating an electrode material, specifically a cathode material. The electrode material is obtained, for example, from or intended for use in electrical energy storage devices, particularly lithium-ion batteries. The electrode material comprises a carrier film and an active material, which is applied to the carrier film by means of a binder material. In other words, the active material, for example in particulate form, is embedded in the binder material, and the binder material is applied to the carrier film together with the active material. In the method described herein, the carrier film is to be separated from the active material. The active material can be detached from the carrier film together with the binder material. For example, the bond between the binder material in which the active material is embedded and the carrier film can be broken, specifically mechanically.

[0007] The invention is based on the finding that the electrode material, particularly in a comminuted form, is fed into an impact mill and the active material is separated from the carrier film in the impact mill, with the electrode material being heated to a specific temperature for the separation of the active material. In other words, it is proposed that the electrode material be heated to a specific temperature during the separation of the active material and the carrier film. The term "heating" can, in particular, include warming or heating the electrode material, i.e., that the temperature of the electrode material is to be specifically increased. By specifically heating the electrode material for the separation of the active material, the efficiency of separating the bond between the active material and the carrier film can be increased, or the bond between the binder material in which the active material is embedded and the carrier film can be weakened, so that the active material can be separated more easily.

[0008] Advantageously, the active material can be more easily separated from the carrier film due to the described temperature control, thus accelerating the separation process. This can, for example, lead to a reduction in the residence time of the electrode material in the impact mill. The electrode material can be fed into the impact mill in a comminuted form, so that, for example, electrode material of a specific particle size is fed into the impact mill. The size of the individual pieces of electrode material can be determined, for example, depending on the impact mill used.

[0009] As described above, the electrode material contains active material applied to the support foil. In one embodiment, the process described herein can be used to separate electrode material whose support foil comprises aluminum, for example, is formed as aluminum foil, and / or whose active material comprises NMC crystals, wherein the active material is detached from the support foil. As described, the support foil can be, for example, aluminum foil or another type of foil, particularly metallic foil. The active material contains relatively valuable components that are to be reused after the separation process. For example, the active material comprises NMC material or NMC crystals, which may include nickel, manganese, cobalt, and lithium. The active material may also contain other components, such as conductive carbon black.

[0010] Furthermore, the process can include tempering the electrode material before and / or during its introduction into the impact mill. In principle, tempering can be performed throughout the entire process. For example, the electrode material can be tempered before it enters the impact mill. Tempering can also occur before and / or during its introduction. Alternatively or additionally, tempering the electrode material within the impact mill is possible. Since the residence time of the electrode material in the impact mill should be as short as possible, tempering the electrode material before it enters the mill is advantageous. This ensures that the electrode material is pre-tempered before entering the impact mill.In particular, temperature control within the impact mill can maintain the temperature of the electrode material, allowing the separation process to be carried out advantageously.

[0011] Specifically, it can be arranged that an impact chamber of the impact mill is tempered or heated while the active material is separated from the carrier film by the impact mill. As described, alternatively or additionally to tempering the electrode material during or before feeding it into the impact mill, tempering can also take place within the impact mill itself. For this purpose, an impact chamber within the impact mill, into which the electrode material is fed and where the mechanical separation between the active material and the carrier film occurs, can be specifically tempered. Either the electrode material can be tempered to the temperature required for the separation process, or the temperature at which the electrode material is fed into the impact mill can be maintained.

[0012] In the described embodiment, it can be provided, in particular, that the impact chamber is tempered by means of at least one heating element arranged outside a sieve ring surrounding a rotor of the impact mill. Such a heating element can also be referred to as a tempering element. Impact elements, for example pins or blades, can be arranged on the rotor of the impact mill, which, through mechanical contact with the electrode material, effect the mechanical separation of the active material and the carrier film. The described rotor can be surrounded by a sieve ring whose mesh size determines the particle size that can exit the sieve ring. Advantageously, the heating elements can be arranged outside the described sieve ring, for example, radially further away from the axis of rotation of the rotor than the sieve ring.

[0013] As previously described, temperature control of the electrode material can also be provided outside the impact mill, particularly during the feeding or transport of the electrode material into the impact mill. Specifically, the electrode material can be pneumatically fed into the impact mill, with the gas stream transporting the electrode material being temperature-controlled. In other words, the described embodiment provides for the electrode material to be transported into the impact mill with the gas stream, which is heated. The transport of the electrode material by means of the heated gas stream transfers heat to the electrode material, thus heating it. As described, this allows the electrode material to be preheated before being fed into the impact chamber of the impact mill.

[0014] In a further embodiment of the method, the electrode material can be heated to a separation temperature that is above the softening temperature of the binder material and / or below its decomposition temperature. In principle, any temperature that facilitates the separation of the active material from the carrier film can be set as the separation temperature. Specifically, the separation temperature should be above the softening temperature of the binder material, so that the binder material is weakened and thus the separation between the carrier film and the active material is improved.

[0015] Specifically, the separation temperature can be set well above the softening temperature, as long as it remains below the decomposition temperature of the binder material. This allows the binder material to be softened in a controlled manner, but not decomposed. For example, if the separation temperature is close to the decomposition temperature, the binder material softens without decomposing, allowing the binder material and any active material incorporated within it to be selectively separated from the carrier film.

[0016] In a further embodiment of the process, the electrode material can be tempered to a separation temperature between 170 °C and 300 °C. The separation temperature to be set can depend on the binder material used. For example, a binder material can be used whose softening temperature is below 170 °C and whose decomposition temperature is above 300 °C. If a different binder material is used, a different separation temperature or temperature range can be specified.

[0017] It follows that the method described herein generates a mixed material stream in which the carrier film and the active material, particularly together with the binder material, are present together but separately from one another. For example, the active material can be present as a powder together with the binder material and exit the impact mill in the mixed material stream along with components of the carrier film. In one embodiment of the method, it can be provided that a material stream comprising the carrier film and the active material separated from the carrier film is fed to a separation device designed to separate the components of the material stream, for example, into separate individual streams.

[0018] In other words, the separation device is designed to separate the carrier film and the active material. The carrier film and the active material are already separated in the material stream, and the goal is to separate the active material from the carrier film, so that the resulting product consists of the carrier film as pure as possible, with the active material separated from it, possibly together with binder material. The separated components can then be reused in appropriate process steps.

[0019] In addition to the described method, the invention relates to a device for separating an electrode material, in particular a cathode material, comprising a carrier film and an active material applied to the carrier film by means of a binder material, wherein the device has an impact mill and is configured to feed the electrode material, in particular in a comminuted form, to the impact mill and to separate the active material from the carrier film in the impact mill, wherein the device for separating the active material from the carrier film is configured for tempering the electrode material.

[0020] All advantages, details, designs and / or features described in relation to the method are fully transferable to the device and vice versa.

[0021] The invention is explained with reference to exemplary embodiments and the figures. The figures are schematic representations and show: Fig. 1. A schematic representation of a device for separating an electrode material according to a first embodiment; and Fig. 2 a schematic representation of a device for separating an electrode material according to a second embodiment.

[0022] Fig. Figure 1 shows a device 1 for separating an electrode material 2, for example for a lithium-ion battery, shown in a schematic section in Fig. Figure 1 shows the electrode material 2, in particular a cathode material, comprising a carrier film 3 and an active material 4 applied to the carrier film 3, which is bonded to the carrier film 3 with a binder material 5. The carrier film 3 can, for example, comprise aluminum or be designed as aluminum foil. The active material 4 is, for example, NMC or comprises, for example, monocrystalline or polycrystalline NMC crystals, which can include, for example, nickel, manganese, cobalt, and lithium. The binder material 5 can, for example, contain at least one further component, such as conductive carbon black.

[0023] In the embodiment according to Fig. Device 1 includes an impact mill 6 in which the electrode material 2 undergoes mechanical separation, i.e., the active material 4 is separated from the carrier film 3, for example, by means of impact elements, specifically pins or blades. Furthermore, device 1 has a flow generation device 7 configured to generate a gas flow 8 by means of which the electrode material 2 is conveyed or transported. The flow generation device 7 is configured to heat or temper the gas flow 8. In particular, the gas flow 8 can be tempered to a separation temperature that lies between the softening temperature of the binder material 5 and its decomposition temperature.

[0024] This means that the electrode material 2, which, for example, can already be shredded before being fed to the flow-generating device 7, can be tempered during transport towards the impact mill 6. As explained below in relation to Fig. As described in section 2, alternatively or additionally, temperature control can also take place within the impact mill 6.

[0025] The pre-tempered electrode material 2 can then be mechanically separated in the impact mill 6, so that active material 4, optionally together with the binder material 5, can be separated from the carrier film 3. This results in a mixed material stream, which can then be fed to a separation device that separates the material stream into individual streams, each containing either only active material 4, optionally with the binder material 5, or only carrier film 3.

[0026] As described, the electrode material 2 can be tempered to a separation temperature between the softening temperature and the decomposition temperature of the binder material 5. For example, the separation temperature can be between 170 °C and 300 °C. However, depending on the binder material 5 used, other separation temperatures are also possible.

[0027] Fig. Figure 2 shows an impact mill 6 in a second embodiment as an example. For example, the impact mill 6 of the embodiment of Fig. 2 in the design of Fig. 1 can be used as the impact mill 6 there. It is also possible to use the impact mill 6 in Fig. 2 by means of a flow generation device 7 to Fig. 1. To supply pre-tempered electrode material 2. Alternatively, any other method of supplying the electrode material 2 is also possible.

[0028] The impact mill 6 has an impact chamber 9 in which the mechanical separation of the active material 4 from the carrier film 3 takes place; that is, the impact chamber 9 describes the volume of the impact mill 6 in which the electrode material 2 is separated into its components. A rotor 10 is rotatably arranged in the impact chamber 9, with impact elements (not shown), such as blades or pins, arranged on the rotor 10 to perform the mechanical separation of the electrode material 2. A sieve ring 11 surrounds the rotor 10, the mesh size of which determines the size of the particles of the carrier film 3 and the active material 4, optionally together with the binder material 5, that can exit the rotor 10.

[0029] With respect to the axis of rotation of the rotor 10, four heating elements 12 are shown, purely as examples, which are designed to temperature-control the impact chamber 9. For example, electrical resistance heating elements can be used as heating elements 12. Alternatively, it is also possible to provide any other heating elements 12 in the impact chamber 9, for example, heating elements 12 through which a working fluid flows. Furthermore, it is possible to integrate heating elements 12 into a lid of the impact mill 6. To ensure thermal insulation, the impact chamber 9 can be thermally insulated so that, for example, a drive unit or a bearing unit of the impact mill 6 is insulated from the temperature-controlled impact chamber 9. A glass fiber reinforced composite material can be used for this purpose.For example, the coupling that connects the rotor 10 to the drive train can also have a heat-insulating function or be designed to be heat-insulating.

[0030] At least one temperature sensor 13 can be arranged in the impact chamber 9 and / or in the flow-generating device 7 and / or along the transport path on which the gas flow 8 transports the electrode material 2. This sensor can detect the current temperature, for example, above the impact elements on the rotor 10 or in the impact chamber 9 or in the flow-generating device 7. A temperature control system can then be implemented to ensure that the separation temperature is reached or maintained.

[0031] How Fig. 1, Fig.As shown in Figure 2, it is therefore possible to temper the electrode material 2 before or during its feed into the impact mill 6 and also to temper the electrical material 2 within the impact mill 6, namely by means of the heating elements 12 in the impact chamber 9.

[0032] As described, the advantages, details, and features shown in the exemplary embodiments can be combined, interchanged, and transferred to one another as desired. The advantages, details, and features described with respect to device 1 are analogously transferable to the method described herein. In particular, the method can be carried out in all its details using device 1 described herein. REFERENCE MARK LIST 1 Device 2 Electrode material 3 carrier film 4 Active material 5 Binder material 6 Impact mill 7 Flow generating device 8 Gas flow 9 Impact chamber 10 Rotor 11 Siebring 12 Heating element 13 Temperature sensor

Claims

Method for separating an electrode material (2), in particular a cathode material, comprising a carrier film (3) and an active material (4) applied to the carrier film (3) by means of a binder material (5), characterized in that the electrode material (2), in particular comminuted, is fed to an impact mill (6) and the active material (4) is separated from the carrier film (3) in the impact mill (6), wherein the electrode material (2) is temperature-controlled for the separation of the active material (4). Method according to claim 1, characterized in that electrode material (2) is separated, the carrier foil (3) of which comprises aluminium and / or the active material (4) of which comprises NMC crystals, wherein the active material (4) is detached from the carrier foil (3). Method according to claim 1 or 2, characterized in that the electrode material (2) is tempered before being fed into the impact mill (6) and / or within the impact mill (6). Method according to one of the preceding claims, characterized in that an impact chamber of the impact mill (6) is heated while the active material (4) is separated from the carrier film (3) by means of the impact mill (6). Method according to claim 4, characterized in that the impact chamber is tempered by means of at least one heating element (12) which is arranged outside a sieve ring (11) surrounding a rotor (10) of the impact mill (6). Method according to one of the preceding claims, characterized in that the electrode material (2) is pneumatically fed to the impact mill (6), wherein a gas stream (8) transporting the electrode material (2) is tempered. Method according to one of the preceding claims, characterized in that the electrode material (2) is tempered to a separation temperature which is above a softening temperature of the binder material (5) and / or below a decomposition temperature of the binder material (5). Method according to one of the preceding claims, characterized in that the electrode material (2) is tempered to a separation temperature between 170°C and 300°C. Method according to one of the preceding claims, characterized in that a material stream comprising the carrier film (3) and the active material (4) separated from the carrier film (3) is fed to a separation device designed to separate the components of the material stream. Device (1) for separating an electrode material (2), in particular a cathode material, comprising a carrier film (3) and an active material (4) applied to the carrier film (3) by means of a binder material (5), characterized in that the device has an impact mill (6) and is designed to feed the electrode material (2), in particular in a comminuted form, to the impact mill (6) and to separate the active material (4) from the carrier film (3) in the impact mill (6), wherein the device for separating the active material (4) from the carrier film (3) is designed for temperature control of the electrode material (2).

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