Method for recycling rechargeable batteries and rechargeable battery processing system

Abstract

The invention relates to a method for recycling rechargeable batteries (10), in particular lithium rechargeable batteries (10) and / or sodium rechargeable batteries, which each consist of at least one galvanic element, each having two poles, and contain a conducting salt dissolved in a conducting salt solvent, comprising the steps of short-circuiting the rechargeable batteries (10) until at least 75% of the galvanic elements have a regeneration cell voltage of at most 0.3 volts, in particular at most 0.2 volts, and subsequently comminuting the rechargeable batteries (10) such that comminution material (18) is obtained.

Description

[0001] Process for recycling batteries and battery processing plant

[0002] The invention relates to a method for recycling accumulators, in particular lithium accumulators or sodium accumulators, which contain a conducting salt dissolved in a conducting salt solvent. The accumulators preferably each consist of at least one galvanic element, each having two poles, and containing a conducting salt dissolved in a conducting salt solvent. In particular, the accumulators consist of a plurality of galvanic elements.

[0003] According to a second aspect, the invention relates to a battery processing plant, in particular a lithium battery and / or sodium battery processing plant, comprising a battery crushing plant for crushing the batteries so that crushed material is obtained, and (b) a washing device for washing the crushed material with a washing solvent so that washing liquid is obtained.

[0004] Batteries that cannot be reused should be recycled. Recycling involves separating the substances or chemical elements present in the batteries so that they can be reused to manufacture batteries or for other purposes.

[0005] It is desirable that reuse, also known as recycling, produces as few unwanted byproducts as possible. In particular, it is desirable that recycling produces as few greenhouse gases as possible, because one of the reasons for the increased use of batteries is the desire to reduce the amount of greenhouse gases produced in the energy supply. Numerous processes are known for recycling batteries, especially lithium batteries, but they have a comparatively large carbon footprint.

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

[0007] The invention is based on the object of improving the recycling of accumulators.

[0008] The invention solves the problem by a method for recycling accumulators, in particular lithium accumulators and / or sodium accumulators, each consisting of at least one galvanic element, each having two poles, and containing a conducting salt dissolved in a conducting salt solvent, comprising the steps of (a) short-circuiting the accumulators until at least 75%, in particular at least 90%, of the galvanic elements have a regeneration cell voltage of at most 0.3 volts, in particular at most 0.2 volts, and (b) then comminuting the accumulators so that comminution material is obtained.

[0009] According to a second aspect, the invention solves the problem by means of an accumulator processing plant comprising (a) an optional accumulator comminution plant for comminuting the accumulators to obtain comminution material, and (b) a high-boiler washing device for washing out conductive salt solvent, in particular a high-boiler fraction of the conductive salt solvent, from the comminution material by means of a high-boiler fraction solvent, to obtain a high-boiler solvent mixture and low-high-boiler comminution material.

[0010] The invention further solves the problem by a method comprising the steps of (a) comminuting the accumulators to obtain comminution material, (b) washing out the conducting salt solvent using a high-boiling fraction solvent, in particular using a low-boiling fraction of the conducting salt solvent, (c) then drying the comminution material, the high-boiling fraction of which has been washed out using 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 a pressure of at most 300 hPa, in particular at most 100 hPa, preferably at most 10 hPa, and (d) then separating plastic parts, in particular plastic film parts, and / or metal foil parts. In this way, the formation of significant amounts of hydrogen fluoride is prevented and the separation of the plastic parts and / or metal foil parts is facilitated.The reason for this is that the high-boiling fraction bonds the plastic parts and / or the metal foil parts to other components, in particular graphite particles and / or particles containing metal components, making separation more difficult. This process preferably comprises step (a) of claim 1. Preferred embodiments mentioned for the other aspects of the invention also apply to this invention. In particular, the pressures do not have to be continuously below the specified pressures.

[0011] For the purposes of this description, the binder refers specifically to the binder of the cathode. The cathode of the accumulator is the cathode during discharge.

[0012] An alkali metal battery is a battery in which an alkali metal, particularly sodium or lithium, or a compound of an alkali metal migrates from one electrode to the other when releasing electrical energy. It is possible, but not necessary, that the oxidation and / or charge of the alkali metal change in the process.

[0013] An alkali metal battery is also known as an alkali metal accumulator. An accumulator is a rechargeable battery. A lithium battery is also known as a lithium accumulator, i.e., a rechargeable battery.

[0014] Examples of alkali metal batteries are lithium-ion batteries such as the lithium cobalt dioxide battery, the lithium polymer battery, the lithium manganese battery, the lithium nickel cobalt manganese battery, the lithium iron phosphate battery, the lithium iron yttrium phosphate battery, the lithium titanate battery, the lithium metal polymer battery and lithium batteries with metallic lithium, as well as the lithium air battery, the lithium sulfur battery, the sodium nickel chloride high-temperature battery, the sodium sulfur battery and the sodium ion battery.

[0015] The crushing material is understood to be the material that is created by crushing the alkali metal batteries.

[0016] When we talk about leaching a conductive salt, we also mean removing the anion of the conductive salt. Instead of leaching the conductive salt, we can also talk about leaching the anion of the conductive salt.

[0017] When graphite is mentioned, other carbon configurations can always be meant in a generalization of the invention.

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

[0019] Short-circuiting the batteries makes it easier to recover the conductive salt or the anion of the conductive salt and / or the lithium. The reason for this is not entirely clear. Presumably, a regeneration cell voltage significantly above 0 V causes local heat generation during crushing, which can promote the decomposition of the conductive salt and / or the formation of hydrogen fluoride. Furthermore, after a prolonged short-circuit, the maximum amount of lithium is present in metallic form rather than as an ion.

[0020] It should be noted that deep discharge alone does not result in a regeneration cell voltage of 0.2 V or less. Deep discharge refers to the withdrawal of current from the accumulator until its capacity is almost completely depleted, in particular below the cut-off voltage. The energy content of the accumulator is very low after deep discharge, because, on the one hand, the cell voltage has dropped significantly and, on the other hand, the achievable discharge current is very small. Therefore, state-of-the-art processes only perform deep discharge. However, it has been shown that even after deep discharge, the energy content is sufficiently high to lead to the formation of hydrogen fluoride.Although the amounts of hydrogen fluoride produced when crushing deeply discharged but not short-circuited batteries are comparatively small, it has been found that even small contamination of the conducting salt and / or the electrolyte with decomposition products can impair the suitability for the production of new batteries.

[0021] It has also been surprisingly shown that deep discharge makes lithium, if present, easier to extract. This is because lithium (which is usually in ionic form) is rarely or never inadvertently removed during the process steps for removing other components.

[0022] The regeneration cell voltage is the cell voltage present at the respective galvanic element after a specified regeneration period, during which the battery's terminals are electrically unconnected. The characteristic that the battery's terminals are electrically unconnected means that the terminals are insulated from each other, i.e., in particular, that there is a resistance of at least 1 megaohm between the two terminals. In other words, no electrical energy is drawn from the galvanic element during the regeneration period. In particular, the terminals of the battery's galvanic elements are electrically unconnected during the regeneration period.

[0023] During the regeneration period, the cell voltage increases. Even discharging a battery to a final charge voltage of, for example, below 0.2 V will result in a regeneration cell voltage of more than 0.2 V if the discharge or short-circuiting is not carried out for a sufficiently long time.

[0024] It was determined that a Samsung INR18650-25R battery, manufactured in February 2022, had a cell voltage of 0 V after a 1-hour short-circuit. The regeneration cell voltage was 1 V. After a 3-hour short-circuit, the cell voltage was 0 V, and the regeneration cell voltage was 0.8 V. After a 5-hour short-circuit, the cell voltage was 0 V, and the regeneration cell voltage was 0.6 V. After a 24-hour short-circuit, the cell voltage was 0 V, and the regeneration cell voltage was 0.2 V.

[0025] Short-circuiting the batteries for such a long time that the regeneration cell 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, can also be referred to as regeneration-safe short-circuiting. It is therefore advantageous if the batteries are shredded only after they have been short-circuited in a regeneration-safe manner.

[0026] Whether a regeneration-safe short-circuit has occurred can be determined by storing the respective battery for the regeneration period without external electrical load, and in particular without a short circuit, at 1013 hPa and 23°C. In other words, a short-circuit of the batteries can occur until at least 75% of the galvanic elements have reached the specified maximum regeneration cell voltage, even if the batteries are crushed or otherwise processed before the end of the regeneration period. The only relevant factor is whether they were short-circuited in such a way that they would not exceed the specified regeneration cell voltage after the regeneration period has expired.

[0027] The regeneration time is 12 hours. Please note that this does not indicate how long the batteries will be short-circuited. In particular, short-circuiting the batteries for 12 hours can still result in the regeneration cell voltage being above 0.2 volts.

[0028] Preferably, the accumulators are short-circuited for a short-circuit time of at least 8 hours, in particular at least 10 hours, preferably at least 12 hours, especially at least 15 hours, especially at least 18 hours. A short-circuit time of at least 20 hours, for example 24 hours, is particularly favorable. The short-circuit time is preferably less than 120 hours. In this way, it can be achieved that—as provided according to a preferred embodiment—at least 90 percent by weight, in particular at least 95 percent by weight, of the conductive salt of the accumulator does not decompose during comminution.

[0029] Preferably, comminution is carried out in such a way that at least 90 mol percent, in particular at least 95 mol percent, and preferably at least 99 mol percent, of the fluorine components of the accumulators remain in the comminution material. In particular, no substance, especially no water, that expels fluorine as a gaseous compound is preferably added.

[0030] It is advantageous if the short-circuit is carried out using a metallic conductor. The metallic conductor connects the battery terminals, i.e., the negative and positive terminals, without any load. This means that the metallic conductor does not connect the battery terminals to an electrical resistor or other electrical load. It is especially advantageous if the negative and positive terminals are not connected using a liquid, especially a saline solution.

[0031] When short-circuiting, an electrical resistance between the positive pole of the accumulator and a negative pole of the accumulator is preferably at most 10 ohms, in particular at most 1 ohm, preferably at most 0.3 ohms.

[0032] It is possible, but not necessary, for the battery to be transported after regeneration-safe short-circuiting, in particular over a distance of at least 1 km, especially at least 5 km. Regeneration-safe short-circuiting minimizes the risk of fire and thus environmental hazards from the battery. Preferably, the battery should not be transported over a distance of more than 1 km after regeneration-safe short-circuiting, as even such transport can pose a safety risk.

[0033] Preferably, after short-circuiting and—according to one embodiment—before any washing out of conducting salt solvent, the method comprises the step of drying the comminution material 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 dried comminution material is obtained.

[0034] Preferably, at least 40 wt.%, in particular at least 50 wt.%, preferably at least 60 wt.%, particularly preferably at least 70 wt.% of the electrolyte solvent is removed by drying. Preferably, at most 95 wt.% of the electrolyte solvent is removed, in particular at most 90 wt.%, particularly preferably at most 85 wt.%.

[0035] After comminution—and optionally after drying—the method according to one embodiment comprises the step of separating plastic parts, in particular plastic film parts, and / or metal foil parts. This is done, for example, by mechanical separation. Mechanical separation is, for example, screening. The metal foil parts are understood to mean, in particular, aluminum foil parts and / or copper foil parts. Preferably, at least 50 percent by weight, in particular at least 65 percent by weight, particularly preferably at least 80 percent by weight, of the plastic parts are separated.

[0036] The process preferably comprises the step of washing out the conducting 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 a cut-off boiling point. The cut-off boiling point is preferably between 120°C and 150°C, in particular 150°C. The cut-off boiling point refers to atmospheric pressure (1013 hPa).

[0037] Preferably, the high-boiling fraction solvent is selected such that it does not react with the conducting salt during washing. In one embodiment, the high-boiling fraction solvent is selected such that it does not form a compound with lithium during washing.

[0038] The goal of leaching the conducting salt solvent is, in particular, to leach a high-boiling fraction of the conducting salt solvent. Therefore, when speaking of leaching the conducting salt solvent, one could also speak of leaching the high-boiling fraction. According to a preferred embodiment, the high-boiling fraction solvent contains at least 80 wt.%, in particular at least 90 wt.%, substances present in the conducting salt solvent that have a boiling point above the cut-off boiling point. For example, the high-boiling fraction includes ethylene carbonate and / or propylene carbonate.

[0039] The high-boiling fraction solvent is preferably obtained by distillation, in particular vacuum distillation, of conducting salt solvent. During vacuum distillation, a temperature of 80°C, in particular 70°C, preferably 60°C, particularly preferably 50°C, in particular 45°C, is preferably not exceeded.

[0040] In particular, it is preferred that the high-boiling fraction solvent be regenerated and / or recycled. The high-boiling fraction is removed from the high-boiling fraction solvent, for example by distillation, and the remaining low-boiling fraction is used as the high-boiling fraction solvent.

[0041] The feature that the high-boiling fraction solvent is regenerated means, in particular, that the regenerated high-boiling fraction solvent is at least partially recombined with the comminution material to wash out the high-boiling fraction. In other words, the high-boiling fraction solvent is at least partially recycled.

[0042] If components of the conducting salt solvent are used to wash out the conducting salt solvent, the high boilers are removed to a very large extent, in particular to at least 90 percent by weight, preferably almost completely, in particular to at least 97 percent by weight. High boilers are substances in the conducting salt solvent with a boiling point above the cut-off boiling point Ts.t.

[0043] Alternatively, a solvent that is not part of the conducting salt solvent can be used to wash out the low-boiling fraction of the conducting salt solvent. In this case, it is advantageous if the solvent has a boiling point at atmospheric pressure of no more than 150°C, especially no more than 110°C. Acetone, for example, is suitable.

[0044] Preferably, no alkaline earth metal hydroxide is used when leaching the conducting salt solvent. In particular, no more than one percent by weight of the lithium reacts with alkaline earth metal hydroxide.

[0045] Preferably, the leaching of the conducting salt solvent is carried out such that at most one-third of the conducting salt is leached out (in weight percent). In other words, the high-boiling fraction solvent extracts essentially no conducting salt. Alternatively or additionally, the leaching of the conducting salt solvent is preferably carried out such that at most one-third of the conducting salt anion (in mole percent) is leached out.

[0046] In one embodiment, the conductive salt is not removed together with the high-boiling fraction. In this case, the ratio QA of the weight of the high-boiling component to the weight of the conductive salt in the accumulators is preferably at least twice as large, in particular at least three times as large, as the ratio QSF in the high-boiling component. In other words, during washing with the conductive salt solvent, the high boilers in the conductive salt solvent are predominantly removed from the crushed material.

[0047] The high-boiling fraction solvent is preferably an organic solvent. In particular, the high-boiling fraction solvent is preferably essentially anhydrous. This means that the water content is at most 1 percent by weight.

[0048] The process preferably comprises the steps of (a) introducing the low-boiling fraction into the comminution material to form a low-boiling-solvent mixture, (b) optionally introducing mechanical energy, for example by stirring, shaking, or ultrasound, into the comminution material, (c) removing the low-boiling-solvent mixture, and (d) producing the low-boiling fraction by distillation to form a high-boiling fraction. The low-boiling fraction is used as the high-boiling fraction solvent. Any excess low-boiling fraction is removed and can be reused to produce accumulators, optionally after purification, for example by distillation. The high-boiling fraction is removed and can be reused to produce accumulators, optionally also after purification, for example by distillation, crystallization, or solvent extraction.

[0049] The process preferably comprises the step of: after washing out the conducting salt solvent, in particular the high-boiling fraction of the conducting salt solvent, drying the comminution material at a temperature of at most 80°C and a pressure of at most 300 hPa, in particular at most 100 hPa, particularly preferably at most 10 hPa, so that comminution material with a low high-boiling content is obtained. Drying largely removes the high-boiling fraction solvent, in particular the low-boiling fraction of the conducting salt solvent, in particular at least 80% by weight, preferably at least 90% by weight, particularly preferably at least 95% by weight. This reduces the binding of the individual particles of the comminution material to one another, which facilitates further processing, for example any subsequent separation.

[0050] In one embodiment of the process, no water is added to the crushed material until this drying process. This prevents a reaction of the conductive salt and / or other components of the electrolyte with water.

[0051] The process preferably comprises the step of separating plastic components, in particular plastic film components, and / or metal foil components from the low-boiling shredded material. This increases the concentration of valuable components, in particular graphite and heavy metals. Furthermore, the plastic components do not dissolve during any subsequent binder removal and thus contaminate the separated binder.

[0052] The reused accumulators contain a binder by means of which graphite particles are bonded to one another and to an electrode, in particular the anode. After washing out the conducting salt solvent and optionally after separating plastic components, in particular plastic film parts and / or metal foil parts, the binder is preferably washed out using a binder solvent. In one embodiment, the binder is washed 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, for the binder to be washed out under excess pressure. It is advantageous that the binder can be recovered undecomposed.

[0053] In one embodiment, the binder solvent contains hydrogen fluoride-precipitating substances, or the binder solvent is contacted with a hydrogen fluoride-precipitating substance. Preferably, no alkaline earth metal hydroxide is used in the leaching of the binder. In particular, at most one percent by weight of the lithium reacts with alkaline earth metal hydroxide.

[0054] It has surprisingly been found that the conducting salt solvent or substances of the conducting salt solvent, such as the low-boiling fraction, are suitable for leaching the binder at sufficiently high temperatures, for example at least 80°C. The binder solvent preferably consists of 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 substances that are constituents of the conducting salt solvent. In particular, the binder solvent is obtained by leaching from the comminution material.

[0055] According to the invention, therefore, a method for recycling accumulators, in particular lithium accumulators and / or sodium accumulators, each consisting of at least one galvanic element, each having two poles, and containing a conducting salt dissolved in a conducting salt solvent, comprising the steps

[0056] (a) crushing the accumulators to obtain crushed material and

[0057] (b) Washing out binder from the comminution material using a binder solvent which consists of 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 substances that are constituents of the conducting salt solvent, preferably belonging to the low-boiling fraction. Preferred embodiments mentioned in connection with other aspects of the invention also apply to this process.

[0058] The binder solvent may also contain or consist of a protic, in particular a protic-polar solvent. The binder solvent preferably consists of at least 70 percent by weight, in particular at least 80 percent by weight, and particularly preferably at least 90 percent by weight, of dimethyl sulfoxide.

[0059] If a protic solvent is used, the binder is washed out in one embodiment 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 prevents the formation of hydrogen fluoride to a significant extent. It is possible, but not necessary, for the binder to be washed out under excess pressure. The feature that the formation of hydrogen fluoride is significantly altered is understood in particular to mean that at most 3 mol percent, in particular at most 1 mol percent, of the fluorine reacts to form hydrogen fluoride during the binder washing out.

[0060] The binder solvent is alternatively or additionally acetone, γ-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), octanoic acid methyl ester, supercritical carbon dioxide or a mixture of two, three, four or more of the chemical compounds mentioned.

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

[0062] Preferably, the binder solvent is circulated and regenerated by removing dissolved binder. For example, the process comprises the steps of (i) supplying the binder solvent to the comminution material, particularly one with a low boiler content, (ii) withdrawing the binder-solvent mixture, and (iii) separating the binder solvent and returning it to the comminution material, particularly one with a low boiler content.

[0063] The separation of the binder solvent occurs, for example, by evaporation. Alternatively or additionally, the separation of the binder solvent occurs by separating the binder. This, in turn, occurs, for example, by reducing the temperature and subsequent filtration, centrifugation, or sedimentation. The binder is removed, and the remaining binder solvent is either reused to wash out the binder or is also removed.

[0064] After washing out the binder, the crushed material or 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 a maximum of 100 hPa, and particularly preferably a maximum of 50 hPa. Since the fluorine content in the crushed material or black mass is often sufficiently low after removal of the binder, drying can also be carried out at higher temperatures without generating excessive amounts of hydrogen fluoride.

[0065] When washing out the binder, preferably no water is added. Preferably, no water and / or aqueous liquid is added to the crushed material until the binder is removed.

[0066] According to a preferred embodiment, the conducting salt or hexafluorophosphate compounds are washed out using an aqueous washing solvent. This preferably occurs after washing out the conducting salt solvent and / or after washing out the binder.

[0067] The washing solvent may contain an acid, for example an organic acid. For example, the organic acid is acetic acid or formic acid. Alternatively, the washing solvent can be basic. The pH is preferably at least 8. For example, the washing solvent contains ammonia or an ammonium compound. Many rechargeable batteries contain a mixture of graphite and metal compound particles, for example NMC (nickel-manganese-cobalt) particles. These can be bonded together by the binder. By removing the binder, the bonds between the graphite and the metal compound particles are reduced to such an extent that the graphite can be separated from the metal compound particles much more easily. The graphite fraction is separated from the metal compound particle fraction, for example, by screening or flotation.For example, sifting is a fine sifting process in which a sifter with a sifting wheel is used.

[0068] The classifying wheel can also be referred to as a grading wheel. The classifying wheel has recesses, in particular slots. The recesses preferably have 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, particularly preferably at most 10 mm.

[0069] Preferably, the fine classifier is designed to rotate the classifying wheel at a classifying wheel rotation frequency between 500 and 20,000 revolutions per second. The higher the classifying wheel rotation frequency, the smaller the aerodynamic diameter of the removed fraction.

[0070] Preferably, the recesses and the rotation frequency are selected such that the graphite fraction has a graphite fraction particle size distribution, wherein 80 volume percent of the graphite has a particle size of less than 20 pm.

[0071] Alternatively or additionally, the recesses and the rotation frequency are selected such that the transition metal fraction has a transition metal fraction particle size distribution, with 90% of the particles having a particle size of less than 35 pm, in particular less than 30 pm. Preferably, at least 50% of the particles have a particle size of less than 25 pm, in particular less than 20 pm. It has been found that a particularly high enrichment factor can be achieved in this way. The particle size is determined according to DIN ISO 13320:2009.

[0072] In the graphite fraction, graphite is enriched by at least a factor of 2, preferably at least a factor of 3, particularly preferably at least a factor of 4, compared to the metal compound particle fraction. In other words, the graphite concentration in the graphite fraction is twice, three times, or four times as high as in the metal compound particle fraction.

[0073] It is possible, but often not necessary, to purify the graphite fraction, which can be done, for example, with sulfuric acid.

[0074] According to a preferred embodiment, at least one metal component is extracted from the metal compound particle fraction, preferably hydrometallurgically. This can be done using a mineral acid, for example, sulfuric acid, for example concentrated sulfuric acid.

[0075] However, it is not necessary for the conducting salt solvent, in particular the high-boiling fraction, to be washed out before separating plastic film parts. According to one embodiment, the method therefore comprises the steps

[0076] (a) Drying the crushed material at a temperature of not more than 80°C and a pressure of not more than 300 hPa, in particular not more than 100 hPa, particularly preferably not more than 10 hPa. The product thus obtained can be called dried crushed material. Thereafter,

[0077] (b) separating plastic components, in particular plastic film components, and / or metal foil components. In particular, these components are separated from the dried shredded material. The product thus obtained can be called black mass. This is followed by

[0078] (c) removal of binder and the high-boiling fraction using the binder solvent. The pressure and temperature ranges specified above, as well as suitable binder solvents, also apply to this embodiment.

[0079] It has surprisingly been found that the more binder solvent used, the less hydrogen fluoride is formed, even when the temperature is above, for example, 80°C. Preferably, therefore, at least 1 liter, preferably at least 2 liters, particularly preferably at least 3 liters, of binder solvent are added per kilogram of black mass. It is possible for the binder and the high-boiling fraction to be removed in batch mode. In this case, the process preferably comprises the steps of (a) adding the binder solvent to the black mass, in particular with the above-mentioned amount of binder solvent. The mixture of binder solvent and black mass can be accelerated to better dissolve the binder. This acceleration is an introduction of mechanical energy. For example, the acceleration comprises stirring, shaking and / or applying ultrasound.

[0080] In a subsequent step (b), the binder-solvent mixture is removed, for example by filtration, suction filtration, centrifugation, or by introducing a fluid. The fluid can be, for example, binder-solvent.

[0081] Steps (a) and (b) are preferably repeated at least once, in particular twice, three times, four times or more.

[0082] Alternatively or additionally, the removal of the binder and the high-boiling fraction can be carried out continuously. In this case, binder solvent is continuously added and the binder-solvent mixture is withdrawn.

[0083] If the binder solvent is regenerated, as provided in a preferred embodiment, the high-boiling fraction of the conducting salt solvent is also separated in addition to the binder. Regeneration is preferably carried out by vacuum distillation.

[0084] After washing out the binder, the conducting 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 both the conducting salt and its anion are washed out and the graphite fraction is separated from the metal compound particle fraction. The flotation is preferably carried out using an aqueous flotation liquid.

[0085] A rechargeable battery processing plant according to the invention could also be called a rechargeable battery reuse plant or rechargeable battery recycling plant. The rechargeable battery processing plant according to the invention is designed to carry out a method according to the invention. It preferably has a device for each of the above-mentioned preferred method steps, which is designed to carry out this method step.

[0086] The separation device comprises, for example, a classifier, in particular a fine classifier or an air classifier, or a flotation system, for example a froth flotation system.

[0087] The binder leaching device preferably has a recovery system for recovering binder solvent. For this purpose, the recovery system has, for example, a suction filter, a filter, or a distillation device, in particular a vacuum distillation device. The recovered binder solvent is reused to leach the binder.

[0088] The accumulator processing plant preferably has a high-boiling fraction washing device arranged in the material flow direction upstream of the binder washing device and downstream of the accumulator comminution plant, which is designed to wash out a high-boiling fraction of the conductive salt solvent of the accumulators by means of the high-boiling fraction solvent, so that a high-boiling solvent mixture and low-high-boiling comminution material are obtained.

[0089] If the accumulator processing plant - as provided according to a preferred embodiment - is designed to wash out the high-boiling fraction and the binder in separate steps, the high-boiling fraction washing device is preferably arranged in the material flow direction upstream of a dryer and upstream of the plastic separation device.

[0090] It is advantageous if the accumulator treatment plant 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. In other words, the high-boiling fraction solvent is circulated. Excess high-boiling fraction solvent is removed and used, for example, for the production of new accumulators.

[0091] The invention is explained in more detail below with reference to the accompanying drawings.

[0092] Figure 1 is a flowchart of a method according to the invention according to a first embodiment,

[0093] Figure 2 shows a flow diagram of a method according to the invention according to a second embodiment,

[0094] Figure 3 is a flowchart of a method according to the invention according to a third embodiment,

[0095] Figure 4 is a flowchart of a method according to the invention according to a fourth embodiment,

[0096] Figure 5 is a schematic representation of an accumulator processing plant according to the invention.

[0097] Figure 1 shows a flowchart of a generic method and the schematic structure of a rechargeable battery processing plant 8 according to the invention. First, the rechargeable batteries to be recycled, of which rechargeable battery 10 is shown, which is composed of galvanic elements 12.i (I = 1, 2, ...), are short-circuited in a step S1 using a discharger 14. For this purpose, a negative pole 15.1 and a positive pole 15.2 are connected to each other by means of the discharger with a resistance of preferably less than 10 ohms. Discharge is only terminated when the galvanic elements 12.1 have a regeneration cell voltage Ureg below Ureg = 0.3 V.

[0098] The accumulator 10 is then crushed in an accumulator crushing system 16 according to a step S2, thus obtaining crushed material 18. The crushed material 18 passes through a preferably dust-tight line 20 from the crushing system 16 into a high-boiler fraction washing device 22. In the high-boiler fraction washing device 22, conductive salt solvent, in particular a high-boiler fraction 24, is washed out according to a step S3. For this purpose, high-boiler fraction solvent 26 is added to the crushed material 18. It is possible, but not necessary, for the high-boiler fraction washing device 22 to have a circulation device, for example, a stirrer.

[0099] The high-boiling fraction solvent 26 is, for example, a conducting salt solvent, by means of which a conducting salt is dissolved in the accumulators 10. The solution of conducting salt solvent and conducting salt forms the electrolyte of the accumulator 10.

[0100] The high-boiling fraction solvent 26 dilutes the electrolyte of the accumulator 10 and thus enriches it with the high-boiling fraction, i.e., with those substances in the conducting salt solvent that have a boiling point above a cut-off boiling point Ts,t. For example, Ts,t = 150 °C.

[0101] For example, the high-boiling fraction washing device 22 has a container 28 in which the comminution material 20 is mixed with the high-boiling fraction solvent 26. This creates a high-boiling fraction solvent mixture 30, which can be fed to a regeneration device 32. In the regeneration device 32, the high-boiling fraction solvent 26 is separated from the high-boiling fraction 24, for example, by vacuum distillation. In this way, low-high-boiling fraction comminution material 18' is obtained.

[0102] The low-boiling comminution material 18' is fed to a dryer 36, in particular through a dust-tight, preferably gas-tight, line 34. In a step S4, the low-boiling comminution material 18' is dried at a temperature of at most 80°C, in the present case at 50°C, under a pressure of, for example, 50 hPa. Drying is optional.

[0103] After drying, the dried shredded material 18" enters an optional plastic separation device 38, in which, according to an optional step S5, plastic components 40 are separated. The plastic components 40 are, for example, parts of a plastic housing or parts of plastic films, in particular separator films. In addition, metal foil parts are preferably separated. In this way, black mass 42 is obtained.

[0104] The black mass 42 enters a binder washout device 44, in which a binder solvent 46 is added to the black mass 42. The binder solvent 46 can be, for example, dimethyl sulfoxide. A temperature T48 in a washout container 48 of the binder washout device 44 is preferably below T48 = 80°C. By washing out binder from the black mass 42 according to a step S6 using the binder solvent 46, a binder-solvent mixture 50 is formed. The binder-solvent mixture 50 is either disposed of or fed to a recovery system 52, which separates the binder solvent 46 from the binder 54 by utilization, filtering, and / or distillation.

[0105] It is optionally possible to wash out the binder solvent 46 using an auxiliary solvent 56 in a subsequent step S7. This is done, for example, in a container 58, but can also be done in the washout container 48.

[0106] The auxiliary solvent 56 has a lower boiling point than the binder solvent 46. The boiling points preferably differ by at least 10 Kelvin. For example, the boiling point Tse of the auxiliary solvent 56 at atmospheric pressure is below 120°C, in particular below 100°C, and particularly preferably below 80°C. Adding the auxiliary solvent 56 to the low-binder black mass 42' creates a mixture 60. The auxiliary solvent 56 and the binder solvent 46 are separated from one another, for example, by means of a distillation device 62.

[0107] It is possible to use a substance from the conducting salt solvent, in particular the low-boiling fraction, as the binder solvent 46. In this case, the temperature T48 is preferably above T48 = 80°C, for example, T48 = 100°C. In order to wash out the binder 54 as efficiently as possible, high temperatures are advantageous. In one embodiment, the binder 54 is therefore washed out at an overpressure, so that the washing out can be carried out at a temperature above the boiling point of the binder solvent. For example, the pressure p48 in the washing tank 48 is p48 = 1500 hPa. In an optional step S8, black mass 42' is dried. This preferably takes place at a temperature of at most 80°C and under a pressure of at most 300 hPa, for example, at most 100 hPa. The dryer 36 can be used for this purpose.

[0108] Subsequently, in an optional conducting salt leaching system 64, according to an optional step S9, conducting salt or the anion of the conducting salt is leached from the black mass 42' using an aqueous liquid 66. This yields a low-fluorine, particularly low-binder, black mass.

[0109] Due to the low binder content, a graphite fraction 70 of the black mass 42' is easily separated from a metal compound particle fraction 72 in a separation device 68 in a step S10. The metal compound particle fraction 72 consists of particles enriched in metal compounds. For example, NMC (nickel-manganese-cobalt) particles are enriched in metal compound particle fraction 70.

[0110] The metal components of the metal compound particle fraction 72 are preferably extracted hydrometallurgically, for example by precipitation or by solvent extraction.

[0111] Figure 2 shows a schematic view of a rechargeable battery processing plant 8 according to the invention and a method according to the invention. After short-circuiting in step S1, the at least one rechargeable battery 10 is crushed in step S2 to produce the crushed material 18. This is dried in the dryer 36. The plastic components 40, in particular plastic film parts and / or metal foil parts, are then separated to obtain the black mass 42. The conducting salt solvent, in particular the high-boiling fraction, is then washed out of the black mass 42. The binder is then washed out. Optionally, the binder solvent is then washed out. The black mass is then optionally dried, and the conducting salt is washed out with the aqueous liquid. The graphite fraction 70 and the metal compound particle fraction 72 are then separated again.Figure 3 shows a schematic view of an accumulator processing plant 8 according to the invention and of a method according to the invention, in which, after short-circuiting and crushing the accumulators, the conducting salt solvent, in particular the high-boiling fraction, is first washed out.

[0112] The shredded material is then dried to make it easier to separate the plastic parts 40 in the next step.

[0113] The conductive salt is then washed out of the resulting black mass 42 with an aqueous liquid, and the black mass 42 is optionally dried. Since the black mass 42 then contains hardly any conductive salt, drying can also be carried out at a drying temperature of more than 100 °C. This causes the aqueous liquid to evaporate. The binder is then washed out, and optionally the binder solvent is removed by washing. After drying, the graphite fraction 70 can then be separated from the metal compound particle fraction 72.

[0114] Figure 4 shows a schematic view of a rechargeable battery processing plant 8 according to the invention and a method according to the invention, in which, after short-circuiting and comminuting the rechargeable batteries and drying the comminution material, the plastic parts, in particular plastic film parts, and / or metal foil parts, are separated. The conducting salt solvent is then washed out, and the black mass is then dried. The conducting salt is then washed out, the black mass is optionally dried, and then the binder is washed out. Optionally, the binder solvent is then washed out, dried if necessary, and then the graphite fraction 70 and metal compound particle fraction 72 are separated.

[0115] Figure 5 shows a further embodiment of a method according to the invention, in which after discharging, optionally short-circuiting according to step (a) of claim 1, the at least one rechargeable battery is shredded. The shredding material 18 is then dried, and the plastic film pieces are separated from the dried shredding material thus obtained. 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°C, in particular at most 60°C, preferably at most 50°C. The binder and the conducting salt solvent are then washed out together. This can be done, for example, using the low-boiling fraction of the conducting salt solvent of the rechargeable batteries 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 normal pressure, i.e., corresponding to ambient pressure, or overpressure. 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 generally less than 150 bar, in particular 100 bar. Alternatively, the binder and the conducting salt solvent are washed out using an organic solvent that is not a component of the conducting salt solvent, for example, dimethyl sulfoxide.

[0116] The black mass 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.

[0117] List of reference symbols

[0118] 8 Accumulator treatment plant 56 Auxiliary solvent 58 Container

[0119] 10 accumulator 60 mixture

[0120] 12 galvanic cells

[0121] 14 Unloader 62 Distillation device

[0122] 16 Accumulator crushing 64 Conductive salt washing plant 66 aqueous liquid

[0123] 18 Shredding material 68 Dryers

[0124] 20 Line 70 Graphite fraction

[0125] 22 High boiler fraction washout 72 Metal compound particle fraction device

[0126] 24 High-boiling fraction Ts,t Separation boiling point

[0127] 26 High-boiling fraction solvents

[0128] 28 containers

[0129] 30 high-boiling solvents

[0130] mixture

[0131] 32 Regeneration device

[0132] 34 Line

[0133] 36 T dryer

[0134] 38 plastic separator

[0135] 40 plastic components

[0136] 42 Black Mass

[0137] 44 Binder washout device

[0138] 46 Binder solvents

[0139] 48 washout tanks

[0140] 50 Binder-solvent mixture

[0141] 52 recovery plant

[0142] 54 binders

Claims

Patent claims 1. Method for recycling accumulators (10), in particular lithium accumulators (10) and / or sodium accumulators, each consisting of at least one galvanic cell having two poles and containing a conducting salt dissolved in a conducting salt solvent, comprising the steps (a) Short-circuit the accumulators (10) until at least 75% of the galvanic cells have a regeneration cell voltage of not more than 0.3 volts, in particular not more than 0.2 volts, and (b) then crushing the accumulators (10) to obtain crushed material (18).

2. The method according to claim 1, characterized by the steps (a) Washing out of conducting salt solvent using a heavy fraction solvent (26), in particular using a light fraction of the conducting salt solvent, (b) wherein the washing takes place at a temperature of not more than 80°C.

3. Method according to one of the preceding claims, characterized by the steps (a) after washing out the conducting salt solvent, drying the comminution material (18) at a temperature of not more than 80°C and a pressure of not more than 300 hPa, so that low-boiling-point comminution material (18) is obtained and (b) Separation of plastic components (40) from the low-density crushed material (18). A method according to any of the preceding claims, characterized by the step of removing binder (54) by means of a binder solvent (46) after washing out the conducting salt solvent. A method according to claim 4, characterized in that (a) the binder solvent (46) consists of at least 50% by weight of substances that are components of the conducting salt solvent and / or (b) the washing out of the binder (54) is carried out at a temperature of at least 80°C, in particular at least 90°C. A method according to any one of the preceding claims, characterized by the step, after removal of the binder (54), washing out the conducting salt using an aqueous washing solvent. A method according to any one of the preceding claims, characterized by the step, after removal of the binder (54), in particular after washing out the conducting salt, separating graphite and a metal compound particle fraction. A method according to any one of the preceding claims, characterized by the steps (a) Drying the comminution material (18) at a temperature of not more than 80°C and a pressure of not more than 300 hPa (so that dried comminution material (18) is obtained), (b) then separating plastic components (40) to obtain black mass (42)) and (c) then removal of binder (54) and a heavy fraction (24) using the binder solvent (46). Accumulator reprocessing plant (8) with (a) an accumulator crushing plant (16) for crushing the accumulators (10) so that crushed material (18) is obtained, (b) a binder washout device arranged downstream of the accumulator crushing unit (16) in the direction of material flow and configured to wash binder (54) out of the crushed material (18) by means of a binder solvent (46) so that binder-poor crushed material (18) is obtained, and (c) a separation device configured to separate a graphite fraction from a metal compound particle fraction (72) of the comminution material (18). Accumulator processing plant (8) according to claim 9, characterized by (a) a heavy fraction washing device (22) arranged in the material flow direction upstream of the binder washing device (44) and downstream of the accumulator comminution unit (16), which is designed to wash out a heavy fraction (24) of the conducting salt solvent of the accumulators (10) by means of a heavy fraction solvent (26), heavy fraction solvent mixture (30) to obtain low-heavy comminution material (18), (b) wherein the heavy fraction washing device (22) comprises a regeneration device (32) for regenerating the heavy fraction solvent (26).

11. Accumulator processing plant (8) according to claim 10, characterized by (a) a dryer (36) arranged downstream of the heavy fraction washout device (22) in the direction of material flow and (b) a plastic separating device (38) arranged in the direction of material flow behind the dryer (36) and in front of the binder washing device for separating plastic parts, in particular plastic film parts.

12. Accumulator processing plant (8) according to one of claims 9 to 11, characterized by a conducting salt washing plant (64) arranged in the material flow direction behind the binder washing device (44) and in front of the separation device for washing out conducting salt by means of an aqueous liquid.

13. Accumulator processing plant (8) according to claim 9, characterized by (a) a dryer (36) arranged downstream of the accumulator crushing unit (16) in the direction of material flow, which is designed for drying at a temperature of at most 60°C and a pressure of at most 300 hPa (b) a plastic separating device (38) arranged in the direction of material flow downstream of the dryer (36) and upstream of the binder washing device (44), (c) a conducting salt washing system (64) arranged in the direction of material flow downstream of the binder washing device (44) and upstream of the separation device for washing out conducting salt.

14. Accumulator processing plant (8) according to one of claims 9 to 13, characterized by a wet chemical processing plant arranged in the material flow direction behind the separation device for wet chemical extraction of at least one metal component from the metal compound fraction.

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