Method for recycling rechargeable battery and rechargeable battery processing system

Abstract

The invention relates to a method for recovering rechargeable cells (10), in particular lithium rechargeable cells (10) and / or sodium rechargeable cells, each cell consisting of at least one galvanic cell, each galvanic cell having two poles and containing a conductive salt dissolved in a conductive salt solvent, the method comprises the following steps: short-circuiting the rechargeable cell (10) until at least 75% of the secondary cell voltage in the galvanic cell has at most 0.3 volts, in particular at most 0.2 volts, and then comminuting the rechargeable cell (10) in order to obtain comminuted material (18).

Description

Technical Field

[0001] The invention relates to a method for recycling rechargeable batteries, in particular lithium batteries or sodium batteries, which contain a conductive salt dissolved in a conductive salt solvent, wherein the batteries preferably each consist of at least one galvanic cell having two poles and containing a conductive salt dissolved in a conductive salt solvent. In particular, the rechargeable battery consists of a plurality of galvanic cells.

[0002] According to a second aspect, the present invention relates to a rechargeable battery processing system, in particular a lithium rechargeable battery and / or sodium rechargeable battery processing system, the system comprising a rechargeable battery pulverizing system for pulverizing rechargeable batteries to obtain pulverized material, and (b) a washing device for washing the pulverized material with a washing solvent to obtain a washing liquid. Background Art

[0003] Rechargeable batteries that cannot be reused should be recycled. Recycling involves separating the substances or chemical elements present in rechargeable batteries so that they can be reused to make rechargeable batteries or for other purposes.

[0004] It is desirable that the recycling process (also referred to as recycling) should produce as few undesirable byproducts as possible. In particular, it is desirable that the recycling process should produce as few greenhouse gases as possible, since one of the reasons for the increased use of rechargeable batteries is the desire to reduce the amount of greenhouse gases produced by the energy supply.

[0005] Various methods are known for recycling rechargeable batteries, in particular lithium rechargeable batteries, but they have a relatively large carbon footprint.

[0006] Above all, it is desirable to recycle as many of the components of a rechargeable battery as possible so that they can be reused to make rechargeable batteries. This has proven difficult. Summary of the invention

[0007] It is an object of the present invention to improve the recycling of rechargeable batteries.

[0008] The invention achieves this object by means of a method for recycling rechargeable batteries, in particular lithium rechargeable batteries and / or sodium rechargeable batteries, each battery consisting of at least one galvanic cell, each galvanic cell having two poles and containing a conductive salt dissolved in a conductive salt solvent, the method comprising the steps of: (a) short-circuiting the rechargeable batteries until at least 75%, in particular at least 90%, of the galvanic cells have a regenerated cell voltage of at most 0.3 V, in particular at most 0.2 V, and (b) then comminuting the rechargeable batteries to obtain comminuted material.

[0009] According to a second aspect, the present invention achieves the above object by means of a rechargeable battery processing system, the system comprising: (a) an optional rechargeable battery pulverizing system for pulverizing the rechargeable battery to obtain pulverized material, and (b) a high boiling point washing device for washing out a conductive salt solvent, especially a high boiling point fraction of the conductive salt solvent, from the pulverized material by means of a high boiling point fraction solvent, thereby obtaining a high boiling point substance-solvent mixture and a pulverized material with a small amount of high boiling point substances.

[0010] The invention also achieves the object by a method comprising the steps of: (a) pulverizing a rechargeable battery to obtain a pulverized material, (b) washing out the conductive salt solvent with the aid of a high-boiling fraction solvent, in particular with the aid of a low-boiling fraction of a conductive salt solvent, (c) then drying the pulverized material, the high-boiling fraction of which has been washed out with the aid of the high-boiling fraction solvent, at a temperature of at most 70° C., preferably at most 60° C., in particular at most 50° C., and at a pressure of at most 300 hPa, in particular at most 100 hPa, preferably at most 10 hPa, and (d) then separating the plastic fraction, in particular the plastic film fraction and / or the metal film fraction. In this way, the formation of large amounts of hydrofluoride is prevented and the separation of the plastic fraction and / or the metal film fraction is facilitated. The reason for this is that the high-boiling fraction adheres the plastic fraction and / or the metal film fraction to other components, in particular graphite particles and / or particles containing metal components, which makes the separation more difficult. The method preferably has step (a) of claim 1. The preferred embodiments mentioned for the other aspects of the invention also apply to the present invention. In particular, the indicated pressure does not necessarily always have to be below these values.

[0011] In the context of this specification, binder is to be understood in particular as the binder of the cathode.The cathode of a rechargeable battery is the cathode during discharge.

[0012] Alkali metal batteries are understood to be batteries in which an alkali metal (especially sodium or lithium) or a compound of an alkali metal migrates from one electrode to the other during the release of electrical energy. Oxidation of the alkali metal and / or a change in charge in the process is possible, but not necessary.

[0013] Alkali metal batteries are also to be understood as meaning alkali metal rechargeable batteries in particular. Rechargeable batteries are to be understood as meaning rechargeable batteries. Lithium batteries are to be understood as meaning lithium rechargeable batteries in particular, ie rechargeable batteries.

[0014] Examples of alkali metal batteries are lithium ion rechargeable batteries such as lithium cobalt oxide rechargeable batteries, lithium polymer rechargeable batteries, lithium manganese rechargeable batteries, lithium nickel cobalt manganese rechargeable batteries, lithium iron phosphate rechargeable batteries, lithium yttrium iron phosphate (Lithium-Eisen-Yttrium-Phosphat-Akkumulator) rechargeable batteries, lithium titanate rechargeable batteries, lithium metal polymer rechargeable batteries and lithium rechargeable batteries with metallic lithium, as well as lithium air rechargeable batteries, lithium sulfur rechargeable batteries, sodium nickel chloride high temperature batteries, sodium sulfur rechargeable batteries and sodium ion rechargeable batteries.

[0015] Comminuted material is understood to be material which is produced by comminuting alkali metal batteries.

[0016] When it is mentioned that the conductive salt is washed out, it should also be understood that the anions of the conductive salt are removed. It can also be said that it is not the conductive salt that is washed out, but the anions of the conductive salt that are washed out.

[0017] When graphite is mentioned, other carbon configurations can always be included within the scope of the present invention.

[0018] The conductive salt solvent preferably contains ethyl methyl carbonate (EMC), ie ethyl methyl carbonate (EMC), and / or dimethyl carbonate (DMC), ie dimethyl carbonate (DMC), and / or ethylene carbonate.

[0019] Short-circuiting the rechargeable battery makes it easier to recover the conductive salt or the anions of the conductive salt and / or the lithium. The principle is not completely clear. It is assumed that the regeneration of the battery voltage well above 0V leads to a local accumulation of heat during the pulverization process, which can lead to the decomposition of the conductive salt and / or the formation of hydrofluoride. In addition, after a long short circuit, the maximum amount of lithium is present in the metallic form, not in the ionic form.

[0020] It should be noted that deep discharge alone does not lead to a regenerated battery voltage of at most 0.2 V. Deep discharge is understood to mean the consumption of current from a rechargeable battery until its capacity is almost completely exhausted, in particular until it falls below the final discharge voltage. After deep discharge, the energy content of a rechargeable battery is very low, since on the one hand the battery voltage drops substantially and on the other hand the achievable discharge current is very low. Therefore, the prior art methods only carry out deep discharge.

[0021] However, it has been found that even after deep discharge, the energy content is high enough to lead to the formation of hydrofluoride. The amount of hydrofluoride produced during the comminution of deeply discharged but not short-circuited rechargeable batteries is relatively small. However, it has been found that even small impurities containing decomposition products in the conductive salt and / or electrolyte can impair the suitability for manufacturing new rechargeable batteries.

[0022] Somewhat surprisingly, deep discharge can make lithium (if present) easier to extract. This is because lithium (usually present in ionic form) is rarely or never inadvertently removed during the process steps that remove other components.

[0023] The regeneration cell voltage is the cell voltage present at the respective primary cell after a specified regeneration time, during which the two poles of the rechargeable battery are electrically disconnected. The fact that the two poles of the rechargeable battery are electrically disconnected means that the two poles are insulated from one another, that is to say in particular that the resistance between the two poles is at least 1 megohm. In other words, during the regeneration time, no electrical energy is drawn from the primary cell. In particular, during the regeneration time, the two poles of the primary cell of the rechargeable battery are not electrically connected.

[0024] During the regeneration time, the battery voltage increases. Even discharging a rechargeable battery to a final charge voltage of, for example, less than 0.2V will result in a regenerated battery voltage exceeding 0.2V unless the discharge or short circuit is performed for a sufficiently long time.

[0025] It was determined that the battery voltage of Samsung's rechargeable battery INR18650-25R manufactured in February 2022 was 0V after 1 hour of short circuit. The regenerated battery voltage was 1V. After 3 hours of short circuit, the battery voltage was 0V, and the regenerated battery voltage was 0.8V. After 5 hours of short circuit, the battery voltage was 0V, and the regenerated battery voltage was 0.6V. After 24 hours of short circuit, the battery voltage was 0V, and the regenerated battery voltage was 0.2V.

[0026] The long-term short circuit of the rechargeable battery so that the regeneration battery voltage is at most 0.4 V, in particular at most 0.3 V, in particular at most 0.2 V, and particularly preferably at most 0.1 V is also called anti-regeneration short circuit. Therefore, it is advantageous to crush the rechargeable battery only after short circuiting in an anti-regeneration manner.

[0027] Whether an anti-regeneration short circuit has occurred can be determined by storing the corresponding rechargeable battery without external electrical load during the regeneration time and in particular without short circuiting at 1013 hPa and 23° C. In other words, short-circuiting the rechargeable battery can occur even if the rechargeable battery is crushed or otherwise handled before the end of the regeneration time, provided that at least 75% of the original cells have the specified maximum regeneration cell voltage. What is most important is whether they have been short-circuited so that they do not exceed the specified regeneration cell voltage after the regeneration time has elapsed.

[0028] The regeneration time is 12 hours. It should be noted that this is not a statement about the length of time the rechargeable battery is short-circuited. In particular, short-circuiting the rechargeable battery for 12 hours may result in a regenerated battery voltage exceeding 0.2 volts.

[0029] Preferably, the rechargeable battery is short-circuited for a short-circuit time of at least 8 hours, in particular at least 10 hours, preferably at least 12 hours, in particular at least 15 hours, in particular at least 18 hours. A short-circuit time of at least 20 hours, for example 24 hours, is particularly advantageous. Preferably, the short-circuit time is less than 120 hours. In this way, as provided in a preferred embodiment, it can be achieved that at least 90% by weight, in particular at least 95% by weight, of the conductive salt of the rechargeable battery does not decompose during the comminution process.

[0030] Preferably, the comminution is carried out so that at least 90 mol%, in particular at least 95 mol% and preferably at least 99 mol% of the fluorine component of the rechargeable battery remains in the comminuted material. In particular, preferably no substances, in particular no water, are added which would disperse the fluorine as a gaseous compound.

[0031] The short circuit is advantageously carried out with a metallic conductor. The metallic conductor connects the two poles of the rechargeable battery, namely the negative pole and the positive pole, without load. This means that the metallic conductor does not connect the two poles of the rechargeable battery to a resistor or any other electrical load. In particular, it is advantageous if the connection of the negative pole and the positive pole is carried out without the aid of a liquid, in particular a saline solution.

[0032] Preferably, when short-circuited, the resistance between the positive terminal of the rechargeable battery and the negative terminal of the rechargeable battery is at most 10 ohms, in particular at most 1 ohm, preferably at most 0.3 ohm.

[0033] It is possible, but not necessary, to transport the rechargeable battery after the regenerative short circuit protection, in particular for a distance of at least 1 km, in particular at least 5 km. The risk of fire and the resulting risk of environmental damage to the rechargeable battery is particularly low due to the regenerative short circuit protection. Preferably, after the regenerative short circuit protection, the rechargeable battery is not transported for a distance of more than 1 km, since such transportation can also pose a safety risk.

[0034] Preferably, the method comprises a step of drying the pulverized material after the short circuit and according to one embodiment before any washing out of the conductive salt solvent at a temperature of at most 80° C., in particular at most 70° C., particularly preferably at most 60° C., for example at most 50° C. Preferably, the drying is carried out at a pressure of at most 300 hPa, in particular at most 50 hPa, particularly preferably at most 10 hPa, so that a dry pulverized material is obtained.

[0035] Preferably, at least 40% by weight, in particular at least 50% by weight, preferably at least 60% by weight, particularly preferably at least 70% by weight of the solvent of the electrolyte is removed by drying. Preferably, at most 95% by weight, in particular at most 90% by weight, preferably at most 85% by weight of the solvent of the electrolyte is removed.

[0036] After the comminution step and, if appropriate, after the drying step, the method comprises, according to one embodiment, a step of separating the plastic fraction, in particular the plastic film fraction and / or the metal film fraction. This is done, for example, by mechanical separation. Mechanical separation is, for example, sorting. The metal film fraction is understood to be, in particular, an aluminum film fraction and / or a copper film fraction. Preferably, at least 50% by weight, in particular at least 65% by weight, most preferably at least 80% by weight of the plastic fraction is separated.

[0037] The method preferably comprises the step of washing out the conductive salt solvent using a high boiling fraction solvent. The high boiling fraction solvent preferably contains at most 1 wt. %, in particular at most 0.1 wt. %, of components whose boiling point is higher than the separation boiling point. The separation boiling point is preferably between 120° C. and 150° C., in particular 150° C. The separation boiling point means at standard pressure (1013 hPa).

[0038] Preferably, the high boiling point fraction solvent is selected so that it does not react with the conductive salt during the washing process. In one embodiment, the high boiling point fraction solvent is selected so that it does not form a compound with lithium during the washing process.

[0039] The purpose of washing out the conductive salt solvent is to wash out the high boiling point fraction of the conductive salt solvent. Therefore, when it is mentioned that the conductive salt solvent is washed out, it can also be said that the high boiling point fraction is washed out.

[0040] According to a preferred embodiment, the high boiling point fraction solvent contains at least 80 wt%, in particular at least 90 wt%, of substances contained in the conductive salt solvent and having a boiling point higher than the separation boiling point. For example, the high boiling point fraction includes ethylene carbonate and / or propylene carbonate.

[0041] The high boiling point fraction solvent is preferably obtained by distillation, in particular vacuum distillation of the conductive salt solvent. In the vacuum distillation, the temperature does not exceed 80°C, in particular 70°C, preferably 60°C, particularly preferably 50°C, in particular 45°C.

[0042] In particular, it is preferred to regenerate and / or recycle the high-boiling-point fraction solvent. For example, the high-boiling-point fraction is removed from the high-boiling-point fraction solvent by distillation, and the remaining low-boiling-point fraction is used as the high-boiling-point fraction solvent.

[0043] Regenerating the high boiling point fraction solvent particularly means that the regenerated high boiling point fraction solvent is at least partially reintroduced into the pulverized material to wash out the high boiling point fraction. In other words, the high boiling point fraction solvent is at least partially recovered.

[0044] When using the components of the conductive salt solvent to wash out the conductive salt solvent, high boilers are removed to a large extent, in particular at least 90% by weight, preferably almost completely, in particular at least 97% by weight. High boilers are components of the conductive salt solvent whose boiling point is higher than the separation boiling point TS,t of substance.

[0045] Alternatively, a solvent which is not part of the conductive salt solvent can be used instead of the low boiling fraction to wash out the conductive salt solvent. In this case, it is advantageous if the solvent has a boiling point of at most 150° C., in particular at most 110° C., at standard pressure. For example, acetone is suitable.

[0046] Preferably, no alkaline earth metal hydroxide is used when washing out the conductive salt solvent. In particular, no more than 1 wt. % of the lithium reacts with the alkaline earth metal hydroxide.

[0047] Preferably, washing out the conductive salt solvent is performed so that at most one-third (by weight) of the conductive salt is washed out. In other words, the high boiling point fraction solvent does not extract any conductive salt. Alternatively or additionally, washing out the conductive salt solvent is preferably performed so that at most one-third (by mole) of the anions of the conductive salt are washed out.

[0048] In one embodiment, the conductive salt is not removed together with the high boiling point fraction. In this case, the ratio of the weight of the high boiling point material in the rechargeable battery to the weight of the conductive salt is Q Ak Preferably, the proportion Q in the high boiling point fraction is SF In other words, during the washing out with the conductive salt solvent, the high boiling point substances in the conductive salt solvent are mainly removed from the pulverized material.

[0049] The high boiling point fraction solvent is preferably an organic solvent. In particular, the high boiling point fraction solvent is preferably substantially free of water. This means that the water content is at most 1% by weight.

[0050] The method preferably comprises the following steps: (a) introducing a low boiling point fraction into a pulverized material to form a low boiling point substance-solvent mixture, i.e. a mixture of a low boiling point substance and a solvent; (b) optionally introducing mechanical energy, such as mechanical energy by stirring, shaking or ultrasound, into the pulverized material; (c) removing the low boiling point substance-solvent mixture; and (d) producing a low boiling point fraction by distillation, thereby forming a high boiling point fraction. The low boiling point fraction is used as a high boiling point fraction solvent. Possibly excessive low boiling point fractions are extracted and can be reused in the production of rechargeable batteries, for example, after purification, for example, by distillation. The high boiling point fraction is extracted and can be reused in the production of rechargeable batteries, for example, after purification, for example, by distillation, crystallization or solvent extraction.

[0051] The method preferably comprises the following step: after washing out the conductive salt solvent, in particular the high boiling fraction of the conductive salt solvent, drying the comminuted material at a temperature of at most 80° C. and a pressure of at most 300 hPa, in particular at most 100 hPa, preferably at most 10 hPa, to obtain a comminuted material with a low content of high boilers. The drying process removes a large part, in particular at least 80% by weight, preferably at least 90% by weight, particularly preferably at least 95% by weight, of the high boiling fraction solvent, in particular the low boiling fraction of the conductive salt solvent. This reduces the adhesion between the individual particles of the comminuted material, thereby facilitating further processing, such as possible subsequent separation.

[0052] In one embodiment of the method, water is not added to the pulverized material until it has been dried. This avoids the conductive salt and / or other components of the electrolyte reacting with the water.

[0053] The method preferably includes a step of separating the plastic components, in particular the plastic film fraction and / or the metal film fraction of the low-boiling comminuted material. This increases the concentration of valuable components, in particular graphite and heavy metals. In addition, the plastic components do not dissolve in a possible subsequent binder removal process and thus contaminate the separated binder.

[0054] The rechargeable battery for reuse contains a binder for binding the graphite particles to each other and to the electrode, in particular the anode. After washing out the conductive salt solvent and, if necessary, after separating the plastic component, in particular the plastic film part and / or the metal film part, the binder is preferably washed out using a binder solvent. In one embodiment, the washing out of the binder is carried out at a temperature of at least 80° C., in particular at least 90° C., preferably at least 100° C. It is possible, but not necessary, that the washing out of the binder is carried out under positive pressure. Advantageously, the binder can be recovered without decomposition.

[0055] In one embodiment, the binder solvent contains a hydrofluoride precipitating substance, or the binder solvent is in contact with a hydrofluoride precipitating substance. Preferably, no alkaline earth metal hydroxide is used when washing out the binder. In particular, up to 1 wt. % of lithium reacts with the alkaline earth metal hydroxide.

[0056] Surprisingly, it has been found that a conductive salt solvent or a substance of a conductive salt solvent, such as a low-boiling fraction, is suitable for washing out the binder at a sufficiently high temperature, for example at least 80° C. Preferably, the binder solvent contains at least 50% by weight, in particular at least 70% by weight, preferably at least 80% by weight, particularly preferably at least 90% by weight of a substance which is a component of the conductive salt solvent. In particular, the binder solvent is obtained by washing out a comminuted material.

[0057] According to the invention, a method for recycling rechargeable batteries, in particular lithium rechargeable batteries and / or sodium rechargeable batteries, each battery consisting of at least one galvanic cell, each galvanic cell having two poles and containing a conductive salt dissolved in a conductive salt solvent, thus also: (a) comminuting the rechargeable batteries to obtain a comminuted material, and (b) washing out the binder from the comminuted material with the aid of a binder solvent, the binder solvent containing at least 50% by weight, in particular at least 60% by weight, particularly preferably at least 70% by weight, preferably at least 80% by weight, in particular at least 90% by weight of a substance that is a component of the conductive salt solvent and preferably belongs to the low-boiling fraction. The preferred embodiments mentioned in conjunction with the other aspects of the invention also apply to the method.

[0058] The binder solvent may also comprise or consist of a protic solvent, in particular a protic polar solvent.Preferably, the binder solvent comprises at least 70 wt. %, in particular at least 80 wt. %, most preferably at least 90 wt. % of dimethyl sulfoxide.

[0059] If a protic solvent is used, in one embodiment, the wash-out of the binder is carried out at a temperature of at most 90° C., in particular at most 80° C., preferably at most 70° C., particularly preferably at most 60° C., for example at most 50° C. This largely prevents the formation of hydrofluorides. The wash-out of the binder can, but not necessarily, be carried out under positive pressure. The significant reduction in the formation of hydrofluorides means in particular that during the wash-out of the binder, at most 3 mol %, and in particular at most 1 mol %, of the fluorine reacts to form hydrofluorides.

[0060] The binder solvent may alternatively or additionally be acetone, g-butyrolactone (GBL), diethyl carbonate (DEC), dimethylacetamide (DMA), N,N-dimethylformamide (DMF), dimethyl sulfoxide (DMSO), 3-heptanone, 3-hexanone, methyl ethyl ketone (MEK), methyl ethyl ketone (MEK), methyl octanoate, supercritical carbon dioxide, or a mixture of two, three, four or more of the above compounds.

[0061] Preferably, washing out of the binder is performed until at least 50% by weight, in particular at least 60% by weight, preferably at least 70% by weight, more preferably 80% by weight of the binder has been removed.

[0062] Preferably, the binder solvent is circulated and regenerated by removing the dissolved binder. For example, the method comprises the steps of: (i) supplying the binder solvent to the comminuted material, in particular containing a small amount of high boilers, (ii) extracting the binder / solvent mixture, and (iii) separating the binder solvent and returning it to the comminuted material, in particular containing a small amount of high boilers.

[0063] For example, the binder solvent is separated by evaporation. Alternatively or additionally, the binder solvent is separated by separating the binder. This in turn is accomplished, for example, by, for example, lowering the temperature and subsequently filtering, centrifuging or settling. The binder is extracted and the remaining binder solvent is either reused to wash out the binder or is also extracted.

[0064] After washing out the binder, the comminuted material or the black mass is preferably dried. Drying is preferably carried out at a maximum of 80° C. and / or a maximum of 300 hPa, in particular at a maximum of 100 hPa, and most preferably at a maximum of 50 hPa. Since the fluorine content in the comminuted material or the black mass is generally sufficiently low after removal of the binder, drying can also be carried out at higher temperatures without excessive hydrofluoride formation.

[0065] Preferably no water is added when washing out the binder. Preferably no water and / or aqueous liquid is added to the comminuted material until the binder has been removed.

[0066] According to a preferred embodiment, the conductive salt or the hexafluorophosphate compound is washed out with the aid of an aqueous washing solvent. This is preferably done after washing out the conductive salt solvent and / or after washing out the binder.

[0067] The washing solvent may contain an acid, such as an organic acid. For example, the organic acid is acetic acid or formic acid. Alternatively, the washing solvent may be alkaline. Preferably, the pH is at least 8. For example, the washing solvent contains ammonia or an ammonium compound.

[0068] Many rechargeable batteries contain a mixture of graphite and metal compound particles, such as NMC (nickel manganese cobalt) particles. These may be glued together using a binder. By removing the binder, the adhesion between the graphite and the metal compound particles is reduced, so that the graphite can be separated from the metal compound particles more easily. The graphite fraction can then be separated from the metal compound particle fraction by means of methods such as classification or flotation. Classification can be a fine classification process using a classifying wheel.

[0069] The classifying wheel can also be called a sizing wheel. The classifying wheel has a recess, in particular a slot. The recess preferably has a clear width, in particular a slot width, of at least 0.1 mm, in particular 1 mm, and / or at most 25 mm, in particular at most 15 mm, and particularly preferably at most 10 mm.

[0070] Preferably, the fine classifier is designed to rotate the classifying wheel at a classifying wheel rotation frequency between 500 and 20000 revolutions per second. The higher the rotation frequency of the classifying wheel, the smaller the aerodynamic diameter of the removed fraction.

[0071] Preferably, the recesses and the rotation frequency are selected such that the graphite fraction has a graphite fraction particle size distribution in which 80% by volume of the graphite has a particle size of less than 20 μm.

[0072] Alternatively or additionally, the recess and the rotation frequency are selected such that the transition metal fraction has a transition metal fraction particle size distribution in which 90% of the particles have a particle size of less than 35 μm, in particular less than 30 μm. Preferably, at least 50% of the particles have a particle size of less than 25 μm, in particular less than 20 μm. It has been found that particularly high concentration factors can be achieved in this way. The particle size is determined in accordance with DIN ISO 13320:2009.

[0073] In the graphite fraction, graphite is concentrated relative to the metal compound particle fraction by at least a factor of 2, preferably at least a factor of 3, more preferably at least a factor of 4. In other words, the graphite concentration in the graphite fraction is two, three or four times higher than in the metal compound particle fraction.

[0074] It is possible, but not usually necessary, to purify the graphite fraction, which can be done, for example, with sulfuric acid.

[0075] According to a preferred embodiment, at least one metal component is extracted from the metal compound particle fraction by hydrometallurgical means. This can be done with a mineral acid, such as sulfuric acid, such as concentrated sulfuric acid.

[0076] However, it is not necessary to wash out the conductive salt solvent, in particular the high boiling point fraction, before separating the plastic film fraction. According to one embodiment, the method thus comprises the following steps:

[0077] (a) drying the pulverized material at a temperature of at most 80° C. and a pressure of at most 300 hPa, in particular at most 100 hPa, and most preferably at most 10 hPa. The product obtained in this way may be referred to as dried pulverized material. Subsequently,

[0078] (b) separating the plastic components, in particular the plastic film fraction and / or the metal film fraction. In particular, these components are separated from the dried pulverized material. The product obtained in this way can be referred to as black mass. Subsequently,

[0079] (c) Removal of binder and high boiling fractions with the aid of a binder solvent The above-mentioned pressure and temperature ranges and the use of a suitable binder solvent also apply to this embodiment.

[0080] Surprisingly it was found that even at temperatures above 80° C., less hydrofluoride is produced the more binder solvent is used. Therefore, at least 1 liter, preferably at least 2 liters, particularly preferably at least 3 liters of binder solvent are added per kg of black mass.

[0081] The removal of the adhesive and the high boiling fraction can be carried out in a batch operation. In this case, the method preferably comprises step (a): adding an adhesive solvent to the black substance, in particular using the above amount of adhesive solvent. The mixing of the adhesive solvent and the black substance can be accelerated to better dissolve the adhesive. This acceleration is the introduction of mechanical energy. For example, the acceleration comprises stirring, shaking and / or ultrasonic treatment.

[0082] In a subsequent step (b), the binder-solvent mixture is removed, for example by filtering, suction, centrifugation or introduction of a fluid. The fluid may be, for example, a solvent for the binder.

[0083] Steps (a) and (b) are preferably repeated at least once, in particular two, three, four or more times.

[0084] Alternatively or additionally, the removal of the binder and the high boiling fraction can be carried out continuously. In this case, the binder solvent is added continuously and the binder-solvent mixture is removed.

[0085] If the binder solvent is regenerated, as provided for in a preferred embodiment, the high-boiling fraction of the conductive salt solvent is also separated off in addition to the binder. The regeneration is preferably carried out by vacuum distillation.

[0086] After washing out the binder, the conductive salt is preferably washed out as described above, and / or the graphite fraction is separated from the metal compound particle fraction. For example, after washing out the binder, flotation is performed so that the conductive salt or its anions are washed out and, in addition, the graphite fraction is separated from the metal compound particle fraction. The flotation is preferably performed with an aqueous flotation liquid.

[0087] The rechargeable battery processing system according to the present invention can also be called a rechargeable battery recycling system or a rechargeable battery reprocessing system. The rechargeable battery processing system according to the present invention is designed to perform the method of the present invention. It preferably has a device for each of the above-mentioned preferred method steps, and the device is designed to perform the method steps.

[0088] The separation device comprises, for example, a classifier, in particular a fine classifier or an air classifier, or a flotation device, for example a froth flotation device.

[0089] Preferably, the adhesive washing device has a recovery device for recovering the adhesive solvent. For this purpose, the recovery device has, for example, a suction filter, a filter or a distillation device, in particular a vacuum distillation device. The recovered adhesive solvent is reused for washing out the adhesive.

[0090] The rechargeable battery processing system preferably has a high boiling point fraction washing out device, which is arranged before the binder washing out device in the material flow direction and after the rechargeable battery pulverizing system, and is designed to wash out the high boiling point fraction in the conductive salt solvent of the rechargeable battery with the help of a high boiling point fraction solvent, thereby obtaining a high boiling point substance-solvent mixture and a pulverized material with a small amount of high boiling point substances.

[0091] If the rechargeable battery processing system is designed to wash out high boiling point fractions and binders in separate steps, as provided in a preferred embodiment, the high boiling point fraction washing device is preferably arranged before the dryer and before the plastic separator viewed in the material flow direction.

[0092] It is advantageous if the rechargeable battery treatment system has a regeneration device for regenerating the high-boiling fraction solvent. In particular, the regeneration device is also designed to separate the high-boiling fraction. The regeneration device can be, for example, a distillation device, in particular a vacuum distillation device. The regenerated high-boiling fraction solvent is reused for washing out. In other words, the high-boiling fraction solvent is recovered. Excess high-boiling fraction solvent is extracted and used, for example, to produce new rechargeable batteries. BRIEF DESCRIPTION OF THE DRAWINGS

[0093] The present invention is explained in more detail below with reference to the accompanying drawings.

[0094] Figure 1 A flow chart showing a method according to a first embodiment of the present invention is shown.

[0095] Figure 2 A flow chart showing a method according to a second embodiment of the present invention is shown.

[0096] Figure 3 A flow chart showing a method according to a third embodiment of the present invention is shown.

[0097] Figure 4 A flow chart showing a method according to a fourth embodiment of the present invention is shown.

[0098] Figure 5 A schematic diagram showing a rechargeable battery handling system according to the present invention is shown. DETAILED DESCRIPTION

[0099] Figure 1 The flowchart of the process according to the invention and the schematic structure of the rechargeable battery processing system 8 according to the invention are shown. First, in step S1, the rechargeable battery to be recycled (rechargeable battery 10 shown in the figure) is short-circuited by means of a discharger 14, and the rechargeable battery consists of primary cells 12.i (i=1, 2, ...). For this purpose, the negative electrode 15.1 and the positive electrode 15.2 are connected to each other by means of a discharger with a resistance preferably less than 10 ohms. Only when the regenerated battery voltage U of the primary cell 12.i isreg Lower than U reg =0.3V, the discharge will be terminated.

[0100] Afterwards, according to step S2, the rechargeable battery 10 is pulverized in the rechargeable battery pulverization system 16, thereby obtaining the pulverized material 18. The pulverized material 18 enters the high boiling point fraction washing device 22 from the pulverization system 16 through a preferably dust-proof pipe 20. In the high boiling point fraction washing device 22, the conductive salt solvent, in particular the high boiling point fraction 24, is washed out according to step S3. For this purpose, the high boiling point fraction solvent 26 is added to the pulverized material 18. The high boiling point fraction washing device 22 may, but need not, have a circulation device, such as a stirrer.

[0101] The high boiling point fraction solvent 26 is, for example, a conductive salt solvent, with the aid of which a conductive salt is dissolved in the rechargeable battery 10. The solution of the conductive salt solvent and the conductive salt forms an electrolyte of the rechargeable battery 10.

[0102] The high boiling point fraction solvent 26 dilutes the electrolyte of the rechargeable battery 10 and thereby enriches itself with the high boiling point fraction, i.e., the conductive salt solvent having a boiling point higher than the separation boiling point T S,t For example, T S,t =150℃.

[0103] For example, the high-boiling fraction wash-off device 22 has a container 28 in which the comminuted material 18 is mixed with the high-boiling fraction solvent 26. This produces a high-boiling-point substance-solvent mixture 30, which can be fed to a regeneration device 32. In the regeneration device 32, the high-boiling-point fraction solvent 26 is separated from the high-boiling-point fraction 24, for example by vacuum distillation. In this way, a comminuted material 18' with a low high-boiling-point substance content is obtained.

[0104] The comminuted material 18' with a low high boiler content is fed in particular via a dust-proof, preferably gas-tight conduit 34 to a dryer 36. In step S4, the low-boiling comminuted material 18' is dried at a temperature of at most 80°C, in the present case 50°C, at a pressure of, for example, 50 hPa. Drying is optional.

[0105] After drying, the dried comminuted material 18 ″ enters an optional plastic separator 38 , wherein a plastic component 40 is separated according to optional step S5 . The plastic component 40 is, for example, a part of a plastic housing or a part of a plastic film, in particular a membrane. Furthermore, preferably a metal film part is separated.

[0106] In this way, the black substance 42 is obtained.

[0107] The black substance 42 enters the binder washing device 44, where a binder solvent 46 is added to the black substance 42. The binder solvent 46 may be, for example, dimethyl sulfoxide. The temperature T in the washing container 48 of the binder washing device 44 is 48 Preferably below T 48 = 80° C. A binder-solvent mixture 50 is produced by washing the binder out of the black substance 42 according to step S6 using the binder solvent 46. The binder-solvent mixture 50 is either disposed of or fed to a recovery system 52 that separates the binder solvent 46 from the binder 54 by use, filtration and / or distillation.

[0108] Optionally, in a subsequent step S7, the binder solvent 46 can be washed out with the aid of an auxiliary solvent 56. This is done, for example, in the container 58, but can also be done in the wash-out container 48.

[0109] The auxiliary solvent 56 has a lower boiling point than the binder solvent 46. Preferably, the boiling points differ by at least 10 Kelvin. For example, the boiling point T of the auxiliary solvent 56 at standard pressure is 56 Below 120° C., in particular below 100° C., particularly preferably below 80° C. Adding auxiliary solvent 56 to low-binder black mass 42 ′ results in mixture 60 . Auxiliary solvent 56 and binder solvent 46 are separated from one another, for example, by means of a distillation device 62 .

[0110] As the binder solvent 46, a substance of a conductive salt solvent can be used, in particular a low boiling point fraction. In this case, the temperature T48 is preferably higher than T48=80°C, for example T48≥100°C. A high temperature is advantageous in order to wash out the binder 54 as effectively as possible. In one embodiment, therefore, the washing out of the binder 54 is carried out under positive pressure so that the washing out can be carried out at a temperature higher than the boiling point of the binder solvent. For example, for a pressure p in the washing out container 48 48 , p 48 ≥1500hPa.

[0111] In optional step S8, the black mass 42' is dried. This is preferably done at a temperature of at most 80°C and a pressure of at most 300 hPa, for example at most 100 hPa. A dryer 36 can be used for this.

[0112] Subsequently, in an optional conductive salt washing out system 64, according to optional step S9, the conductive salt or anions of the conductive salt are washed out of the black mass 42' by means of an aqueous liquid 66. In this way, a black mass having a low fluorine content and in particular a low binder content is obtained.

[0113] Due to the low binder content, the graphite fraction 70 of the black matter 42' can be easily separated from the metal compound particle fraction 72 in the separation device 68 in step S10. The metal compound particle fraction 72 is composed of particles in which the metal compound is concentrated. For example, NMC (nickel manganese cobalt) particles are rich in the metal compound particle fraction 72.

[0114] The metal components in the metal compound particle fraction 72 are preferably extracted by hydrometallurgical methods, such as by precipitation or solvent extraction.

[0115] Figure 2 A schematic diagram of a rechargeable battery processing system 8 and method according to the invention is shown. After short-circuiting according to step S1, at least one rechargeable battery 10 is comminuted in step S2 to form comminuted material 18. This is dried in a dryer 36. Thereafter, the plastic component 40, in particular the plastic film fraction and / or the metal film fraction, is separated, thereby obtaining a black substance 42. The conductive salt solvent, in particular the high boiling point fraction, is then washed out from the black substance 42. Thereafter, the binder is washed out. Optionally, the binder solvent is then washed out. Subsequently, the black substance is dried and the conductive salt is washed out with an aqueous liquid. Thereafter, the graphite fraction 70 and the metal compound particle fraction 72 are separated again.

[0116] Figure 3 A schematic diagram of a rechargeable battery processing system 8 and method according to the present invention is shown, wherein, after short-circuiting and crushing the rechargeable battery, the conductive salt solvent, in particular the high-boiling fraction, is first washed out. Afterwards, the crushed material is dried so that the plastic component 40 can be separated more easily in a subsequent step.

[0117] Afterwards, the conductive salt is washed out of the resulting black substance 42 using an aqueous liquid, and the black substance 42 is then optionally dried. Since the black substance 42 contains hardly any conductive salt, drying can also be performed at a drying temperature exceeding 100° C. This causes the aqueous liquid to evaporate. The binder is then washed out, and optionally, the binder solvent is removed by washing out. After drying, the graphite fraction 70 can then be separated from the metal compound particle fraction 72.

[0118] Figure 4 A schematic diagram of a rechargeable battery processing system 8 and method according to the present invention is shown, wherein after short-circuiting and pulverizing the rechargeable battery and drying the pulverized material, the plastic fraction, in particular the plastic film fraction and / or the metal film fraction is separated. Thereafter, the conductive salt solvent is washed out and the black matter is then dried. Thereafter, the conductive salt is washed out, the black matter is dried if necessary, and then the binder is washed out. Optionally, the binder solvent is then washed out and dried if necessary, and then the graphite fraction 70 and the metal compound particle fraction 72 are separated.

[0119] Figure 5A further embodiment of the process according to the invention is shown, in which, after discharge, optionally short-circuiting, according to step (a) of claim 1, at least one rechargeable battery is comminuted. The comminuted material 18 is then dried and the plastic film fraction is separated from the dried comminuted material obtained in this way. Drying is preferably carried out at a pressure of at most 300 hPa, in particular 100 hPa, preferably at most 10 hPa. The temperature during drying is preferably at most 70°, in particular at most 60°, preferably at most 50°.

[0120] Afterwards, the binder and the conductive salt solvent are washed out together. This can be done, for example, with the aid of a low-boiling fraction of the conductive salt solvent of the rechargeable battery at a temperature of at least 70° C., preferably at least 80° C., particularly preferably at least 90° C., in particular at least 100° C., for example at least 110° C. The temperature is below the boiling point at the corresponding pressure. The pressure can be standard pressure, i.e. ambient pressure, or positive pressure. For example, the pressure is at least 1.5 bar, in particular at least 2 bar, for example at least 3 bar. The pressure is typically less than 150 bar, in particular 100 bar. Alternatively, the binder and the conductive salt solvent are washed out using an organic solvent that is not part of the conductive salt solvent, for example using dimethyl sulfoxide.

[0121] The black substance can then be dried, but this is not necessary. In a subsequent step, the conductive salt is washed out using an aqueous liquid. The graphite fraction and the metal compound particle fraction are then separated from each other.

[0122] Reference numerals list

[0123] 8 Rechargeable battery handling system

[0124] 10. Rechargeable battery

[0125] 12 Primary battery

[0126] 14 Discharger

[0127] 16 Rechargeable Battery Crushing System

[0128] 18 Crushed materials

[0129] 20 Pipe

[0130] 22 High boiling point fraction washing device

[0131] 24 High boiling point fraction

[0132] 26 High boiling point fraction solvent

[0133] 28 Container

[0134] 30 High boiling point substance-solvent mixture

[0135] 32 Regeneration device

[0136] 34 Pipe

[0137] 36 Dryer

[0138] 38 Plastic separator

[0139] 40 Plastic components

[0140] 42 Black Matter

[0141] 44 Adhesive washing device

[0142] 46 Adhesive solvent

[0143] 48 Wash out container

[0144] 50 Adhesive-Solvent Mixture

[0145] 52 Recycling System

[0146] 54 Adhesive

[0147] 56 Auxiliary solvent

[0148] 58 Container

[0149] 60 Mixture

[0150] 62 Distillation Unit

[0151] 64 Conductive salt washing system

[0152] 66 Aqueous Liquid

[0153] 68 Dryer

[0154] 70 Graphite fraction

[0155] 72 Metal compound particle fraction

[0156] T S,t Separate boiling point.

Claims

1. A method for recycling rechargeable batteries (10), in particular lithium rechargeable batteries (10) and / or sodium rechargeable batteries, each battery consisting of at least one galvanic cell, each galvanic cell having two poles and containing a conductive salt dissolved in a conductive salt solvent, the method comprising the following steps: (a) short-circuiting the rechargeable battery (10) until at least 75% of the primary cells have a regenerated cell voltage of at most 0.3 volts, in particular at most 0.2 volts, and (b) The rechargeable battery (10) is then pulverized to obtain pulverized material (18).

2. The method according to claim 1, characterized by the following steps: (a) washing out the conductive salt solvent with the aid of a high boiling point fraction solvent (26), in particular with the aid of a low boiling point fraction of the conductive salt solvent, (b) wherein the washing out is carried out at a temperature of up to 80°C.

3. The method according to any one of the preceding claims, characterized by the following steps: (a) drying the pulverized material (18) at a temperature of at most 80° C. and a pressure of at most 300 hPa after washing out the conductive salt solvent to obtain a pulverized material (18) having a low content of high boiling substances, and (b) separating a plastic component (40) from the comminuted material (18) having the low content of high boiling substances.

4. The method according to any one of the preceding claims, characterized by the following steps: After washing out the conductive salt solvent, the binder (54) is removed with the aid of a binder solvent (46).

5. The method according to claim 4, characterized in that (a) the binder solvent (46) contains at least 50% by weight of a substance that is a component of the conductive salt solvent, and / or (b) The washing out of the binder (54) is performed at a temperature of at least 80°C, in particular at least 90°C.

6. The method according to any one of the preceding claims, characterized by the following steps: After the binder (54) has been removed, the conductive salt is washed out with the aid of an aqueous washing solvent.

7. The method according to any one of the preceding claims, characterized by the following steps: After the binder (54) has been removed, in particular after the conductive salt has been washed out, the graphite and metal compound particle fractions are separated.

8. The method according to any one of the preceding claims, characterized by the following steps: (a) drying the pulverized material (18) at a temperature of at most 80° C. and a pressure of at most 300 hPa (so as to obtain a dried pulverized material (18)), (b) subsequently separating the plastic component (40) so as to obtain a black substance (42), and (c) The binder (54) and the high boiling point fraction (24) are then removed with the aid of the binder solvent (46).

9. A rechargeable battery processing system (8), comprising: (a) a rechargeable battery pulverizing system (16), the rechargeable battery pulverizing system being used to pulverize the rechargeable battery (10) to obtain pulverized material (18), (b) a binder washing device, which is arranged downstream of the rechargeable battery pulverizing system (16) in the material flow direction and is designed to wash out the binder (54) from the pulverized material (18) with the aid of a binder solvent (46), thereby obtaining a pulverized material (18) with a low binder content, and (c) a separation device configured to separate a graphite fraction from a metal compound particle fraction (72) of the pulverized material (18).

10. The rechargeable battery processing system (8) according to claim 9, characterized in that: (a) a high boiling point fraction washing device (22), which is arranged upstream of the binder washing device (44) and downstream of the rechargeable battery pulverization system (16) in the material flow direction, and is designed to wash out the high boiling point fraction (24) of the conductive salt solvent of the rechargeable battery (10) with the help of a high boiling point fraction solvent (26), thereby obtaining a high boiling point substance-solvent mixture (30) and a pulverized material (18) with a low content of high boiling points, (b) A high boiling point fraction eluting device (22), the high boiling point fraction eluting device having a regenerating device (32) for regenerating the high boiling point fraction solvent (26).

11. The rechargeable battery processing system (8) according to claim 10, characterized in that: (a) a dryer (36) arranged downstream of the high boiling point fraction washing device (22) in the material flow direction, and (b) A plastic separator (38) which is arranged downstream of the dryer (36) and upstream of the binder wash-out device for separating plastic parts, in particular plastic film parts.

12. The rechargeable battery processing system (8) according to any one of claims 9 to 11, characterized in that: A conductive salt washing system (64) is used to wash out the conductive salt by means of an aqueous liquid, and is arranged downstream of the binder washing device (44) and upstream of the separation device in the material flow direction.

13. The rechargeable battery processing system (8) according to claim 9, characterized in that: (a) a dryer (36) arranged downstream of the rechargeable battery comminution system (16) in the material flow direction, the dryer being designed for drying at a temperature of at most 60° C. and a pressure of at most 300 hPa, (b) a plastic separator (38) which is arranged downstream of the dryer (36) and upstream of the binder washing-out device (44) in the material flow direction, (c) A conductive salt washing system (64) arranged downstream of the binder washing device (44) and upstream of the separation device in the material flow direction for washing out conductive salt.

14. The rechargeable battery processing system (8) according to any one of claims 9 to 13, characterized in that: A wet chemical treatment system is arranged downstream of the separation device in the material flow direction for wet chemical extraction of at least one metal component from the metal compound fraction.

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