Method for recovering excess material of a solid-state battery

Abstract

The present invention relates to a method for recovering at least one excess material during the method for producing a solid-state battery. The method comprises the steps of: flooding (100) the part of the system that has come into contact with a slurry with a first solvent; separating (200) the first solution into a first solid material and a supernatant; dissolving (300) the first solid material in a second solvent that is different from the first solvent; recrystallizing (400) and drying (500) the second solution; and drying (600) the supernatant.

Description

[0001] Method for recovering excess material from a solid-state battery

[0002] The present invention relates to a method for recovering at least one excess material during the manufacturing process of a solid-state battery.

[0003] A lithium-metal secondary battery comprises a positive transition metal oxide-based cathode, a negative metallic lithium anode, and a liquid electrolyte that is lithium-ion conductive between the positive and negative electrodes. Because the liquid electrolyte is flammable, it is necessary to design the battery with a device configured to minimize the temperature rise within the battery in the event of a short circuit. The risks associated with the use of liquid electrolyte batteries are increasing with the rapidly growing demand for batteries with high capacity and energy density, particularly to meet the widespread goals of the transportation industry's transition from gasoline to electric vehicles.

[0004] Solid-state batteries use a solid electrolyte instead of a liquid one, resulting in a solidified battery. This configuration allows for the storage of electrochemical energy without additional safety devices, as the battery itself is non-flammable and resistant to a wide temperature range. Furthermore, such solid-state batteries have much higher energy densities compared to conventional lithium-ion batteries, which use liquid electrolytes. For these reasons, solid-state batteries are attracting increasing interest across many industries.

[0005] As battery adoption rapidly increases, so does the challenge of managing the process residues generated during production. These residues not only contaminate the equipment used, thus reducing its lifespan, but also contain valuable components that can be recovered and reused for environmental and cost reasons. This saves costs and resources. A further advantage is the reduction of waste.

[0006] Despite the rapidly growing interest in solid-state batteries, there are no known methods to recycle the process waste generated during the manufacture of solid-state batteries, which poses a potential problem of unused resources in the near future.

[0007] Therefore, it would be desirable to provide a process that supports the manufacturing process of a solid-state battery in a resource-efficient manner.

[0008] One objective of the invention is to propose a method that avoids or at least reduces some of the disadvantages known in the prior art. This objective is achieved according to the invention by means of a

[0009] Method according to the main claim.

[0010] The subject matter of the main claim relates to a method for recovering at least one excess material during the manufacturing process of a solid-state battery. The method comprises a step of flooding the part of the system that has come into contact with a slurry with a first solvent to form a first solution such that the binder contained in the slurry is dissolved in the supernatant. Furthermore, the method comprises a step of separating the first solution into a first solid and a supernatant. The method further comprises a step of dissolving the first solid in a second solvent that differs from the first solvent. Finally, the method comprises a step of recrystallizing and drying the second solution such that the second solvent is removed and the first solid is present in recrystallized form.Furthermore, the process includes a step of drying the supernatant, such that the first solvent is removed and the binder is present in the form of a second solid.

[0011] The process according to the invention comprises a step of flooding the parts of the system that have come into contact with a slurry with a first solvent in order to form a first solution such that the binder contained in the slurry is dissolved in the supernatant. Flooding such a system is known to those skilled in the art. For example, the flooding can be carried out by the same method used to introduce the slurry into the system.

[0012] In a preferred embodiment, the binder comprises a polymer. Such polymers are known to those skilled in the art.

[0013] In a more preferred embodiment, the polymer is selected from the group consisting of styrene-butadiene rubber (SBR), hydrogenated acrylonitrile butadiene rubber (HNBR), polyisobutylene (PIB), polymethyl methacrylate (PMMA) and ethylene-vinyl acetate copolymer (PEVA).

[0014] Polyisobutylene (PIB), also known under the trade name Oppanol, can be used in this process.

[0015] The term "slurry" refers to a mixture of materials that form an electrode paste. These materials can include, for example: active materials, conductivity additives, binders, and solvents.

[0016] A slurry can be a suspension or a paste.

[0017] In a preferred embodiment, the slurry can be a cathode slurry. In another preferred embodiment, the slurry can be an anode slurry.

[0018] In another preferred embodiment, the slurry can be an electrolyte slurry.

[0019] In a preferred embodiment, the first solvent is designed such that it dissolves the binder.

[0020] Preferably, the first solvent is designed such that it can dissolve the binder but cannot dissolve a sulfidic electrolyte used. Possible binders for corresponding sulfidic electrolytes are known to those skilled in the art. Furthermore, possible sulfidic electrolytes could be, for example, those mentioned in this disclosure.

[0021] Furthermore, preferably the first solvent is a nonpolar solvent which has a polarity that allows the binder to dissolve.

[0022] Nonpolar solvents are known to those skilled in the art. The various degrees of polarity of solvents are known to those skilled in the art.

[0023] In a preferred embodiment, the first solvent is selected from the group consisting of toluene, xylene, and benzene. In a further preferred embodiment, the first solvent is selected from the group consisting of toluene and xylene.

[0024] The first solvent, toluene, is particularly preferred.

[0025] The first solution can therefore contain all the substances contained in the slurry as well as the first solvent.

[0026] The cathode slurry can contain the cathode active material, a solid electrolyte, and a conductive additive.

[0027] A cathode active material within the meaning of the invention is understood to be a material which can be used in a cathode.

[0028] In accordance with the invention, the cathode acts as the positive terminal. The anode slurry can contain the anode active material, optionally a conductive additive, preferably a carbon-based conductive additive.

[0029] Furthermore, the anode slurry can contain the anode active material, optionally a conductive additive, preferably a carbon-based conductive additive, and optionally a solid electrolyte.

[0030] For the purposes of this invention, an anode-active material is understood to be a material that can be used in an anode. -1-

[0031] An anode within the meaning of the invention is an electrode at which oxidation processes take place during the discharge process of the battery cell, i.e., the oxidation state of the electrochemical active material increases with the release of electrons.

[0032] When the anode and the cathode are connected to form a circuit, electrodes flow to the cathode via this external connection; in this external circuit, the anode acts as the negative pole.

[0033] Furthermore, an anode within the meaning of the invention can be an electrode in which lithium ions are released during discharge, as is the case, for example, with a lithium-ion secondary battery.

[0034] The electrolyte slurry can contain the binder, the electrolyte, and residues thereof.

[0035] The equipment used in the manufacture of a solid-state battery and the corresponding parts of the equipment that come into contact with the material of the solid-state battery to be manufactured are known to those skilled in the art.

[0036] The manufacturing process of a solid-state battery is divided into three main sections: electrode and electrolyte manufacturing, cell assembly, and

[0037] Cell finalization is divided into stages. Excess materials are generated during the cell manufacturing process. Larger quantities, particularly suitable for industrial scaling of the proposed process, are generated during electrode and electrolyte production, especially in the manufacture of separator, anode, and cathode pastes.

[0038] Cathode production includes the steps of grinding and mixing, coating, calendering, longitudinal separation and singulation, which preferably takes place in a dry / cleanroom.

[0039] The grinding and mixing can be carried out using a planetary mixer, preferably under normal ambient conditions, or an extruder, preferably in a dry / cleanroom. The parts of the system used in this process, and consequently the parts of the system contaminated with process residues, are known to those skilled in the art.

[0040] In longitudinal cutting during cathode production, for example, the rollers used (longitudinal cutting by roller knives) and the conveyor belts used (longitudinal cutting by roller knives and lasers) can be the parts of the system contaminated with process residues.

[0041] Electrolyte production can include the steps of grinding and mixing, optional coating, optional lamination, optional calendering, singulation and optional sintering.

[0042] The grinding and mixing can be carried out using a ball mill, preferably under normal ambient conditions, a planetary mixer, preferably in a dry / cleanroom, or an extruder, preferably under normal ambient conditions.

[0043] The coating process can be carried out using aerosol deposition or film casting, each preferably in a dry / cleanroom.

[0044] When using a ball mill, for example, the parts of the system contaminated with process residues can be the grinding drum, the grinding balls used, and all parts used when inserting the electrolyte into the grinding drum.

[0045] When using a planetary mixer or intensive mixer, for example, the parts of the system contaminated with process residues can include the container used, the mixing tools, and all parts used when adding the electrolyte to the container.

[0046] In coating by means of coextrusion, for example, the parts of the system contaminated with process residues can include the container used, the extrusion tools used, and all parts used when inserting the electrolyte into the container.

[0047] In calendering, for example, the rollers used in electrolyte production can be the parts of the system that come into contact with process residues. Similarly, in longitudinal cutting, the rollers used (longitudinal cutting by rotary knives) and the conveyor belts used (longitudinal cutting by rotary knives and lasers) can be the parts of the system contaminated with process residues.

[0048] The electrolyte melt can be produced in a compounding process. This process can involve, for example, the parts of the system contaminated with process residues, such as the tank, the twin-screw extruder, and all parts used when introducing the electrolyte into the tank.

[0049] In coating by means of film casting, for example, the parts of the system contaminated with process residues can include the containers used, the slot nozzle including the slot nozzle head, and the feed hoses.

[0050] In the case of coating using aerosol deposition, for example, the parts of the system contaminated with process residues can be the containers used, such as the process chamber and mixing chamber, the substrate holder, the nozzle and the feed hoses.

[0051] The method according to the invention comprises a step of separating the first solution into a solid and a supernatant.

[0052] Method for separating a solid and the

[0053] The supernatant from a solution is known to those skilled in the art. Separation can be carried out using a filter system. Suitable filter systems are known to those skilled in the art. For example, a filter or a sieve can be used. Preferably, a filter or sieve is used whose pore size is less than 8 pm, preferably less than 5 pm.

[0054] In a preferred embodiment, the first solid comprises a solid electrolyte.

[0055] In a more preferred embodiment, the solid electrolyte is based on lithium and sulfur. Such solid electrolytes are known to those skilled in the art.

[0056] In a more preferred embodiment, the production of the solid electrolyte Li2S and P2S5, as well as precursors thereof, is carried out. Corresponding production processes and the associated precursors are known to those skilled in the art.

[0057] Furthermore, the electrolyte may contain lithium halides and other metal sulfides, such as germanium sulfide.

[0058] In a preferred embodiment, the solid electrolyte comprises LiePSsCl .

[0059] In another preferred embodiment, the first solid comprises cathode active material and solid electrolyte, as well as optionally a conductive additive.

[0060] Suitable solid electrolytes are known to those skilled in the art. In particular, the solid electrolytes mentioned above can be used. In a more preferred embodiment, the

[0061] Cathode active material Ni-Li-Mn-Co oxide (NMC).

[0062] Preferably, the NMC material is selected from the group consisting of lithium manganese nickel oxide (LMNO), lithium iron phosphate (LFP), lithium cobalt (III) oxide (LCO), lithium nickel cobalt aluminum oxide (NCA), lithium manganese iron phosphate (LMFP), lithium manganese aluminum oxide (LMA), lithium manganese (III,IV) oxide (LMO) and combinations thereof.

[0063] In a more preferred embodiment, the NMC material is lithium cobalt (III) oxide.

[0064] In another preferred embodiment, the first solid comprises anode active material and optionally a conductive additive.

[0065] Conductive additives, also called conductive additives, are used to improve electrical conductivity or electrical transport. The conductive additive can be a known electrically conductive material. Conductive additives are known to those skilled in the art.

[0066] For example, the conductive additive can be selected from the group consisting of conductive carbon black, carbon nanotubes (CNTs), graphene, graphite and mixtures thereof.

[0067] Conductive carbon blacks are well known to experts. Conductive carbon black can include, for example, (Super) C65, C45 or similar.

[0068] In a preferred embodiment, the anode active material is selected such that it can store and / or intercalate lithium.

[0069] Intercalation within the meaning of the invention is the incorporation of molecules, ions (rarely also atoms) into chemical compounds, whereby these do not substantially change their structure during the incorporation process.

[0070] Preferably, the anode active material is selected such that it has a potential which is as low as possible relative to lithium.

[0071] Preferably, the anode active material can have the potential of a lithium titanate (LTO) battery or a lower potential. For example, LTO has a potential of 1.5V (relative to lithium).

[0072] Preferably, the anode material is selected to have the highest possible capacity.

[0073] In a particularly preferred embodiment, the anode active material is selected from the group consisting of silicon, carbon, carbon black, silver nanoparticles and combinations thereof.

[0074] The anode active material is preferably selected from silicon and carbon or carbon black and silver nanoparticles. The process according to the invention comprises a step of dissolving the first solid in a second solvent that differs from the first solvent.

[0075] Preferably, the dissolution of the first solid can be carried out in a dry room atmosphere.

[0076] Protective gas atmospheres are known to those skilled in the art. Argon is preferably used as a protective gas.

[0077] Preferably, the dissolution of the first solid can take place in a cleanroom.

[0078] Preferably, the dissolving of the first solid can be carried out while stirring.

[0079] Preferably, the first solid can be dissolved by heating.

[0080] Preferably, the heating temperature when dissolving the first solid can be selected such that it is below the boiling point of the chosen solvent.

[0081] Furthermore, the dissolution of the first solid can preferably take place in a cleanroom under stirring and heating.

[0082] In a preferred embodiment, the second solvent is a polar solvent selected from the group consisting of ethanol, methanol, propanol, butanol, acetonitrile, and tetrahydrofuran. In a more preferred embodiment, the second solvent comprises anhydrous ethanol.

[0083] The process according to the invention comprises a step of recrystallization and drying of the second solution, such that the second solvent is removed and the first solid is present in recrystallized form.

[0084] Preferably, the drying and recrystallization can take place under exclusion of air, i.e. preferably in a dry room atmosphere.

[0085] For example, drying and recrystallization can be carried out in a protective gas oven. The temperature can be, for example, 500-550 °C. The temperature in the protective gas oven allows the structure of the solid to crystallize.

[0086] The process according to the invention includes a step of drying the supernatant, such that the first solvent is removed and the binder is present in the form of a second solid.

[0087] Suitable drying methods are known to those skilled in the art. For example, drying can be carried out by heating the solid to crystallization temperature or by heating it so that the solvent is removed.

[0088] Special design forms

[0089]

[0001] Method for recovering at least one excess material during the manufacturing process of a solid-state battery, the method comprising the following steps:

[0090] Flooding (100) the part of the plant that has come into contact with a slurry with a first solvent to form a first solution such that the binder contained in the slurry is dissolved in the supernatant;

[0091] Separating (200) the first solution into a solid and a supernatant;

[0092] Dissolving (300) the first solid in a second solvent which is different from the first solvent;

[0093] Recrystallization (400) and drying (500) of the second solution such that the second solvent is removed and the first solid is in recrystallized form;

[0094] Drying (600) the supernatant such that the first solvent is removed and the binder is present in the form of a second solid.

[0095] [2] Method according to paragraph [1] , wherein the first solvent is designed to dissolve the binder.

[0096] [3] A method according to any of the preceding paragraphs, wherein the first solvent is designed to dissolve the binder but cannot dissolve a sulfide electrolyte. [4] A method according to any of the preceding paragraphs, wherein the first solvent is a nonpolar solvent having a polarity that enables it to dissolve the binder.

[0097] [5] Method according to any of the preceding paragraphs, wherein the first solvent is selected from the group consisting of toluene, xylene and benzene, preferably toluene and xylene, and further preferably toluene.

[0098] [6] Method according to any of the preceding paragraphs, wherein the second solvent is a polar solvent selected from the group consisting of ethanol, methanol, propanol, butanol, acetonitrile, tetrahydrofuran and mixtures thereof.

[0099] [7] Method according to paragraph [6] , wherein the second solvent is anhydrous ethanol.

[0100] [8] Method according to any of the preceding claims, wherein the binder comprises a polymer.

[0101] [9] Method according to paragraph [8] , wherein the polymer is selected from the group consisting of styrene-butadiene rubber (SBR) , hydrogenated acrylonitrile butadiene rubber (HNBR) , polyisobutylene (PIB) , polymethyl methacrylate (PMMA) and ethylene-vinyl acetate copolymer (PEVA) .

[0102]

[0010] A method according to any of the preceding paragraphs, wherein the first solid comprises a solid electrolyte.

[0011] A method according to paragraph

[0010] , wherein the solid electrolyte is based on lithium and sulfur, preferably comprising the production of the solid electrolyte Li₂S and P₂S₅ and precursors thereof, and further preferably comprising the solid electrolyte LiePSsCl.

[0103]

[0012] Method according to one of paragraphs [1] to [9] , wherein the first solid comprises cathode active material and solid electrolyte and optionally conductive additive.

[0104]

[0013] Method according to paragraph

[0012] , wherein the cathode active material comprises Ni-Li-Mn-Co-oxide (NMC), preferably selected from the group consisting of lithium manganese nickel oxide (LMNO), lithium iron phosphate (LFP), lithium cobalt(III) oxide (LCO), lithium nickel cobalt aluminum oxide (NCA), lithium manganese iron phosphate (LMFP), lithium manganese aluminum oxide (LMA), lithium manganese

[0105] (III, IV) oxide (LMO) and combinations thereof.

[0106]

[0014] Method according to one of paragraphs [1] to [9] , wherein the first solid comprises anode active material and optionally a conductive additive.

[0107]

[0015] Method according to paragraph

[0014] , wherein the anode active material is selected such that it can store and / or intercalate lithium.

[0108]

[0016] Method according to paragraph

[0015] , wherein the anode active material is selected such that it has a potential that is as close as possible to the potential of lithium or has a minimized potential difference with respect to lithium.

[0017] Method according to paragraph

[0014] or

[0015] , wherein the anode active material is selected from the group consisting of silicon, carbon, carbon black, silver nanoparticles and combinations thereof, preferably silicon and carbon black or carbon black and silver nanoparticles.

[0109] Further advantages and features will result from the following description of a design form with reference to the attached figure.

[0110] Fig. 1: a schematic view of an embodiment of the method for recovering at least one excess material during the manufacturing process of a solid-state battery.

[0111] Figure 1 shows a schematic representation of the process for recovering at least one excess material during the manufacturing process of a solid-state battery. The process comprises: flooding (100) the parts of the system that have come into contact with a slurry with a first solvent to form a first solution such that the binder contained in the slurry is dissolved in the supernatant. The process further comprises separating (200) the first solution into a first solid and a supernatant. The process further comprises dissolving (300) the first solid in a second solvent that differs from the first solvent. The process further comprises recrystallization (400) and drying (500) of the second solution such that the second solvent is removed and the first solid is present in recrystallized form.Furthermore, the process involves drying (600) the supernatant such that the first solvent is removed and the binder is present in the form of a second solid.

[0112] Reference symbol list

[0113] 100 Flooding the part of the plant that has come into contact with a slurry with a first solvent to form a first solution, such that the binder contained in the slurry is dissolved in the supernatant;

[0114] 200 Separation of the first solution into a first solid and a supernatant. 300 Dissolving the first solid in a second solvent that differs from the first solvent.

[0115] 400 Recrystallization such that the first solid is present in recrystallized form. 500 Drying of the second solution such that the second solvent is removed.

[0116] 600 Drying of the supernatant, such that the first solvent is removed and the binder is present in the form of a second solid.

Claims

1. A method for recovering at least one excess material during the manufacturing process of a solid-state battery, the method comprising the following steps: Flooding (100) the part of the plant that has come into contact with a slurry with a first solvent to form a first solution such that the binder contained in the slurry is dissolved in the supernatant; Separating (200) the first solution into a first solid and a supernatant; Dissolving (300) the first solid in a second solvent which is different from the first solvent; Recrystallization (400) and drying (500) of the second solution such that the second solvent is removed and the first solid is in recrystallized form; Drying (600) the supernatant such that the first solvent is removed and the binder is present in the form of a second solid.

2. The method of claim 1, wherein the second solvent comprises a polar solvent selected from the group consisting of ethanol, methanol, propanol, butanol, acetonitrile, tetrahydrofuran and mixtures thereof.

3. The method of claim 2, wherein the second The solvent contains anhydrous ethanol.

4. Method according to any of the preceding claims, wherein the binder comprises a polymer.

5. Method according to any one of the preceding claims, wherein the first solid comprises a solid electrolyte.

6. The method of claim 5, wherein the solid electrolyte is based on lithium and sulfur, preferably comprising the production of the solid electrolyte Li2S and P2S5 as well as precursors thereof, and further preferably comprising the solid electrolyte LiePSsCl.

7. Method according to any one of claims 1 to 4, wherein the first solid comprises cathode active material and solid electrolyte and optionally a conductive additive.

8. The method of claim 7, wherein the cathode active material comprises Ni-Li-Mn-Co-oxide (NMC), preferably selected from the group consisting of lithium manganese nickel oxide (LMNO), lithium iron phosphate (LFP), lithium cobalt (III) oxide (LCO), lithium nickel cobalt aluminum oxide (NCA), lithium manganese iron phosphate (LMFP), lithium manganese aluminum oxide (LMA), and lithium manganese (III, IV) oxide. (LMO) and combinations thereof.

9. A method according to any one of claims 1 to 4, wherein the first solid comprises anode active material and optionally a conductive additive.

10. A method according to claim 7, wherein the The anode active material is selected in such a way that it can store and / or intercalate lithium.

Images