Rechargeable battery recycling method and rechargeable battery processing system

Abstract

The present invention relates to a method for recycling accumulators (10), in particular lithium rechargeable batteries (10) and / or sodium rechargeable batteries (10), each consisting of at least one galvanic element, each having two poles and containing a conductive salt dissolved in a conductive salt solvent, comprising the steps of short-circuiting the accumulator (10) until at least 75% of the galvanic elements have a regenerated cell voltage of at most 0.3 volts, in particular at most 0.2 volts, and grinding the accumulator (10) to obtain a grinding material (18).

Description

[Technical field]

[0001] The present invention relates to a method for recycling rechargeable batteries, in particular lithium or sodium batteries, containing a conductive salt dissolved in a conductive salt solvent, preferably each battery consisting of at least one galvanic element having two poles and containing a conductive salt dissolved in a conductive salt solvent. In particular, rechargeable batteries consist of a plurality of galvanic elements.

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

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

[0004] It is desirable for the recycling process, also known as recycling, to produce as few unwanted by-products as possible, particularly since the increased use of rechargeable batteries is in part due to a desire to reduce the amount of greenhouse gases produced by energy supplies.

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

[0006] In particular, it is desirable to recycle as many of the components of a rechargeable battery as possible so that they can be reused in the manufacture of rechargeable batteries, which has proven difficult. Summary of the Invention

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

[0008] The present invention solves this problem by a method for recycling rechargeable batteries, in particular lithium and / or sodium rechargeable batteries, each consisting of at least one galvanic element, having two poles and containing a conductive salt dissolved in a conductive salt solvent, comprising the steps of: (a) short-circuiting the rechargeable battery until at least 75%, in particular at least 90%, of the galvanic elements have a regenerated cell voltage of less than or equal to 0.3 volts, in particular less than or equal to 0.2 volts; and (b) grinding the rechargeable battery to obtain ground material.

[0009] According to a second aspect, the present invention solves this problem by a rechargeable battery treatment system comprising (a) an optional rechargeable battery grinding system for grinding rechargeable batteries to obtain ground material, and (b) a high boiler cleaning device for cleaning the conductive salt solvent, in particular the high boiler fraction of the conductive salt solvent, from the ground material with a high boiler fraction solvent, so as to obtain a high boiler / solvent mixture and ground material with less high boiler.

[0010] The invention also solves this problem by a method comprising the steps of (a) grinding the rechargeable battery to obtain a ground material, (b) washing the conductive salt solvent with a high boiler fraction solvent, in particular with a low boiler fraction of the conductive salt, (c) then drying the ground material from which the high boiler fraction has been washed with the high boiler fraction solvent at a temperature below 70° C., preferably below 60° C., in particular below 50° C., and at a pressure below 300 hPa, in particular below 100 hPa, preferably below 10 hPa, and (d) then separating the plastic parts, in particular the plastic foil parts and / or the metal foil parts. In this way, the formation of large amounts of hydrogen fluoride is prevented and the separation of the plastic parts and / or the metal foil parts is facilitated, since the high boiler fraction causes the plastic parts and / or the metal foil parts to adhere to other components, in particular graphite particles and / or particles containing metal components, making the separation difficult. The process preferably comprises the step (a) according to claim 1. The preferred embodiments mentioned for the other aspects of the invention also apply to the present invention. In particular, the pressures indicated do not always have to be below these values.

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

[0012] An alkali metal battery is understood to be a battery in which an alkali metal, in particular sodium or lithium, or a compound of an alkali metal, is transferred from one electrode to the other during the release of electrical energy. It is possible, but not necessarily, that the oxidation and / or charge of the alkali metal changes during the process.

[0013] Alkali metal batteries are also understood to mean, in particular, alkali metal storage batteries. Storage batteries are understood to mean, in particular, rechargeable batteries. Lithium batteries are understood to mean, in particular, lithium rechargeable batteries, i.e. batteries.

[0014] Examples of alkali metal batteries are lithium ion rechargeable batteries, e.g. lithium cobalt dioxide rechargeable batteries, lithium polymer rechargeable batteries, lithium manganese rechargeable batteries, lithium nickel cobalt manganese rechargeable batteries, lithium iron phosphate rechargeable batteries, lithium iron yttrium phosphate rechargeable batteries, lithium titanate rechargeable batteries, lithium metal polymer rechargeable batteries, and lithium rechargeable batteries having 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] Ground material is understood to be material produced by grinding alkali metal batteries.

[0016] When referring to washing the conductive salt, it is understood that the anions of the conductive salt are also removed. Instead of washing the conductive salt, it can also be said that the anions of the conductive salt are washed.

[0017] Whenever graphite is mentioned, other carbon configurations may also be included in the generalization of the present invention.

[0018] The conductive salt solvent preferably comprises methyl ethyl ester of carbonic acid, ie ethyl methyl carbonate (EMC), and / or dimethyl ester of carbonic acid, ie dimethyl carbonate (DMC), and / or ethylene carbonate.

[0019] Short-circuiting a rechargeable battery facilitates recovery of the conductive salt or the anion of the conductive salt and / or lithium. Why this is the case is not fully understood. Presumably, a regeneration cell voltage significantly above 0 V can cause a local increase in temperature during grinding, which can promote decomposition of the conductive salt and / or formation of hydrogen fluoride. Also, after a long period of short circuiting, the maximum amount of lithium is present in metallic form rather than as ions.

[0020] It should be noted that only deep discharge does not lead to a regenerated cell voltage of up to 0.2 V. Deep discharge is understood to mean the discharge of current from a rechargeable battery until its capacity is almost completely depleted, in particular below the final discharge voltage. After deep discharge, the energy content of a rechargeable battery is very low, because on the one hand the cell voltage drops significantly and on the other hand the achievable discharge current is very low. Therefore, only deep discharge is performed in modern processes.

[0021] However, it has been found that even after deep discharge, the energy content is high enough to result in the formation of hydrogen fluoride. The amount of hydrogen fluoride produced during grinding of a deeply discharged but not shorted rechargeable battery is relatively small. However, it has been found that even small amounts of impurities of the electrolyte with conductive salts and / or decomposition products can impair the manufacturability of new rechargeable batteries.

[0022] It has also been shown, unexpectedly, that deep discharge can facilitate the extraction of lithium, if present, since lithium (usually present in ionic form) is rarely or unintentionally removed during process steps to remove other components.

[0023] The regenerated cell voltage is the cell voltage present at each galvanic element after a certain regeneration time when the poles of the rechargeable battery are electrically disconnected. Electrically disconnecting the poles of the rechargeable battery means that the poles are insulated from each other, i.e. in particular that there is a resistance of 1 megohm or more between the two poles. In other words, no electrical energy is extracted from the galvanic element during the regeneration time. In particular, the poles of the galvanic element of the rechargeable battery are not electrically connected during the regeneration time.

[0024] During the regeneration time, the cell voltage will increase. Even if a rechargeable battery is discharged below the final charge voltage, say 0.2V, it will still result in a regenerated cell voltage above 0.2V unless it is discharged or shorted for a long enough period of time.

[0025] A Samsung INR18650-25R rechargeable battery manufactured in February 2022 was determined to have a cell voltage of 0V after 1 hour of short circuiting. The regenerated cell voltage was 1V. After 3 hours of short circuiting, the cell voltage was 0V and the regenerated cell voltage was 0.6V. After 24 hours of short circuiting, the cell voltage was 0V and the regenerated cell voltage was 0.2V.

[0026] Short-circuiting a rechargeable battery for an extended period of time such that the regenerated cell voltage is below 0.4 V, particularly below 0.3 V, particularly below 0.2 V, particularly preferably below 0.1 V, is also referred to as regenerated short-circuit resistant. It is therefore preferred to crush the rechargeable battery only after short-circuiting in a regenerated short-circuit resistant manner.

[0027] Whether or not regeneration short circuit resistance has been achieved can be determined by storing the corresponding rechargeable battery for the regeneration time without an external electrical load, in particular without short circuit at 1013 hPa and 23 °C. In other words, even if the rechargeable battery is crushed or otherwise treated by the end of the regeneration time, a short circuit of the rechargeable battery can occur, provided that more than 75% of the galvanic elements have the specified maximum regeneration cell voltage. The only issue is whether the rechargeable battery has been short circuited in such a way that the specified regeneration cell voltage is not exceeded after the regeneration time has elapsed.

[0028] The regeneration time is 12 hours. Note that this is not a statement of how long the rechargeable battery is shorted. In particular, if a rechargeable battery is shorted for 12 hours, the regenerated cell voltage may exceed 0.2 volts.

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

[0030] Preferably, the grinding is carried out so that at least 90 mol %, in particular at least 95 mol %, preferably at least 99 mol % of the fluorine content of the rechargeable battery remains in the ground material. In particular, it is preferred that no substances, in particular water, which release fluorine as gaseous compounds are added.

[0031] The short circuit is preferably effected by a metallic conductor, which connects the poles of the rechargeable battery, i.e. the negative and positive poles, without a load. This means that the metallic conductor does not connect the poles of the rechargeable battery to an electrical resistance or any other electrical load. In particular, it is preferred that the connection between the negative and positive poles is not effected by a liquid, in particular a salt solution.

[0032] Preferably, in the case of a short circuit, the electrical resistance between the positive terminal of the rechargeable battery and the negative terminal of the rechargeable battery is 10 ohms or less, in particular 1 ohm or less, preferably 0.3 ohms or less. After the rechargeable battery has withstood the regenerative short circuit, it is possible, but not necessarily, to be transported over a distance of, in particular, 1 km or more, in particular 5 km or more. Due to the regenerative short circuit resistance, the risk of fire and environmental hazard from the rechargeable battery due to fire is particularly low. Since transportation over a distance of more than 1 km may pose a safety risk, it is preferred that the rechargeable battery is not transported over such a distance after the regenerative short circuit resistance.

[0033] Preferably, the method comprises, after the short circuit and according to one embodiment before washing out the conductive salt solvent, a step of drying the ground 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 as to obtain a dry ground material.

[0034] 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 electrolyte solvent 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 electrolyte solvent is removed.

[0035] After the grinding step and, if appropriate, after the drying step, the method according to an embodiment comprises a step of separating the plastic part, in particular the plastic foil part and / or the metal foil part. This is carried out, for example, by mechanical separation. The mechanical separation is, for example, classification. The metal foil part is understood to be, in particular, the aluminum foil part and / or the copper foil part. Preferably, at least 50 weight percent, in particular at least 65 weight percent, most preferably at least 80 weight percent of the plastic part is separated.

[0036] The process preferably comprises washing the conductive salt solvent with a high boiler fraction solvent, which 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 refers to standard pressure (1013 hPa).

[0037] Preferably, the high boiler fraction solvent is selected so as not to react with the conductive salt during washing. In one embodiment, the high boiler fraction solvent is selected so as not to form compounds with lithium during washing.

[0038] The purpose of washing the conductive salt solvent is in particular to wash the high boiler fraction of the conductive salt solvent. Therefore, when talking about washing the conductive salt solvent, it can also be said that the high boiler fraction is washed.

[0039] According to a preferred embodiment, the high boiler fraction solvent contains at least 80% by weight, in particular at least 90% by weight, of substances contained in the conductive salt solvent and having a boiling point above the separation boiling point, for example the high boiler fraction contains ethylene carbonate and / or propylene carbonate.

[0040] The high boiler fraction solvent is preferably obtained by distillation, in particular vacuum distillation, of the conductive salt solvent, in which the temperature does not exceed 80°C, in particular 70°C, preferably 60°C, particularly preferably 50°C, in particular 45°C.

[0041] In particular, it is preferred that the high boiler fraction solvent is regenerated and / or recycled: the high boiler fraction is removed from the high boiler fraction solvent, for example by distillation, and the remaining low boiler fraction is used as the high boiler fraction solvent.

[0042] By the high boiler fraction solvent is regenerated it is meant in particular that the regenerated high boiler fraction solvent is at least partially reintroduced into the grinding material in order to wash the high boiler fraction, in other words the high boiler fraction solvent is at least partially recycled.

[0043] When the conductive salt solvent component is used to wash the conductive salt solvent, the high boilers are removed to a very high extent, in particular up to 90 weight percent or more, preferably almost completely, in particular up to 97 weight percent or more. The high boilers have a separation boiling point T S,t It is a conductive salt solvent material having a boiling point above

[0044] Alternatively, a solvent that is not a low boiling fraction and is not part of the conductive salt solvent can be used to wash the conductive salt solvent. In this case, it is advantageous for the solvent to have a boiling point at standard pressure of 150° C. or less, in particular 110° C. or less. Acetone is suitable, for example.

[0045] Preferably, no alkaline earth metal hydroxides are used when washing the conductive salt solvent, in particular, no more than 1 weight percent of the lithium reacts with alkaline earth metal hydroxides.

[0046] Preferably, washing the conductive salt solvent is performed such that up to one third (by weight percent) of the conductive salt is washed out. In other words, the high boiler fraction solvent does not extract the conductive salt. Alternatively or additionally, washing the conductive salt solvent is preferably performed such that up to one third (by mole percent) of the anions of the conductive salt are washed out.

[0047] In one embodiment, the conductive salt is not removed with the high boiler fraction. In this case, the ratio Q of the weight of the high boiler to the weight of the conductive salt in the rechargeable battery is AK is the ratio Q in the high boiler fraction SF Preferably, the ratio is at least two times, particularly at least three times. In other words, during washing of the conductive salt solvent, the high boiler in the conductive salt solvent is largely removed from the ground material.

[0048] The high boiler fraction solvent is preferably an organic solvent. In particular, the high boiler fraction solvent is preferably substantially free of water, meaning that the water content is 1 weight percent or less.

[0049] The process preferably comprises the steps of (a) introducing a low boiler fraction into the ground material to form a low boiler / solvent mixture, i.e. a mixture of low boiler and solvent, (b) optionally introducing mechanical energy into the ground material, for example by stirring, vibration or ultrasound, (c) removing the low boiler / solvent mixture, and (d) forming a high boiler fraction by producing a low boiler fraction by distillation. The low boiler fraction is used as a high boiler fraction solvent. The excess low boiler fraction is removed and can be reused for the manufacture of rechargeable batteries, optionally after purification, for example by distillation. The high boiler fraction is removed and can be reused for the manufacture of rechargeable batteries, optionally after purification, for example by distillation, crystallization or solvent extraction.

[0050] The process preferably comprises a step of drying the ground material at a temperature of 80° C. or less and a pressure of 300 hPa or less, in particular 100 hPa or less, preferably 10 hPa or less, after washing the conductive salt solvent, in order to obtain a ground material with a low content of high boilers. The drying process removes a large part of the high boiler fraction solvent, in particular the low boiler fraction of the conductive salt solvent, in particular 80 weight percent or more, preferably 90 weight percent or more, particularly preferably 95 weight percent or more. This reduces adhesion between the individual particles of the ground material, facilitating further processing, for example any subsequent separation.

[0051] In one embodiment of the method, water is not added to the ground material until it is dry, which avoids reaction of the conductive salt and / or other components of the electrolyte with water.

[0052] The process preferably includes a step of separating the plastic components, in particular the plastic and / or metal foil fractions, of the low boiling point ground material, which results in a high concentration of valuable components, in particular graphite and heavy metals, and the plastic components do not dissolve during the subsequent debinding and therefore do not contaminate the separated binder.

[0053] The rechargeable battery to be reused contains a binder used to bind the graphite particles to each other and to the electrodes, in particular the anode. After washing of the conductive salt and, if necessary, after separating the plastic components, in particular the plastic foil part and / or the metal foil part, the binder is preferably washed with a binder solvent. In one embodiment, the washing of the binder is carried out at a temperature of 80° C. or more, in particular 90° C. or more, preferably 100° C. or more. The washing of the binder can be carried out under positive pressure, but this is not necessary. Advantageously, the binder can be recovered without decomposition.

[0054] In one embodiment, the binder solvent contains or is contacted with a hydrogen fluoride precipitating material. Preferably, no alkaline earth metal hydroxide is used to wash the binder. In particular, only up to 1 weight percent of lithium reacts with alkaline earth metal hydroxide.

[0055] Surprisingly, the conductive salt solvent or the material of the conductive salt solvent, for example the low boiler fraction, is suitable for washing the binder at sufficiently high temperatures, for example above 80° C. Preferably, the binder solvent is composed of at least 50 weight percent, in particular at least 70 weight percent, preferably at least 80 weight percent, particularly preferably at least 90 weight percent of the material which is a component of the conductive salt solvent. In particular, the binder solvent is obtained by washing the ground material.

[0056] Therefore, according to the invention, a method for recycling rechargeable batteries, in particular lithium and / or sodium rechargeable batteries, each composed of at least one galvanic element, each having two poles and containing a conductive salt dissolved in a conductive salt solvent, comprises the steps of: (a) crushing rechargeable batteries to obtain crushed material; and (b) washing the binder from the ground material with a binder solvent, preferably consisting of substances that are components of the conductive salt solvent, preferably belonging to the low boiling fraction, to the extent of 50% by weight or more, in particular 60% by weight or more, particularly preferably 70% by weight or more, preferably 80% by weight or more, particularly preferably 90% by weight or more. The preferred embodiments mentioned in connection with the other aspects of the invention also apply to this process.

[0057] The binder solvent may contain or consist of a protic solvent, particularly a protic polar solvent, preferably consisting of at least 70 weight percent, particularly at least 80 weight percent, most preferably at least 90 weight percent dimethylsulfoxide.

[0058] When a protic solvent is used, in an embodiment, washing the binder is carried out at 90° C. or less, in particular 80° C. or less, preferably 70° C. or less, particularly preferably 60° C. or less, for example 50° C. or less. This largely prevents the formation of hydrogen fluoride. Washing the binder can be, but is not required to be, carried out under positive pressure. By significantly reduced hydrogen fluoride formation is meant in particular that only up to 3 mol %, in particular up to 1 mol %, of fluorine reacts to form hydrogen fluoride during washing the binder.

[0059] The binder solvent may alternatively or additionally be acetone, gamma butyrolactone (GBL), diethyl carbonate (DEC), dimethylacetamide (DMA), N,N-dimethylformamide (DMF), dimethylsulfoxide (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 aforementioned chemical compounds.

[0060] Preferably, the binder is washed until at least 50 weight percent, especially at least 60 weight percent, preferably at least 70 weight percent, and even more preferably at least 80 weight percent of the binder has been removed.

[0061] Preferably, the binder solvent is recycled and regenerated by removing the dissolved binder. For example, the process may comprise the steps of: (i) supplying binder solvent to the low-boiler ground material; (ii) removing the binder / solvent mixture; and (iii) separating the binder solvent and returning it to the low-boiler ground material.

[0062] The binder solvent is separated, for example, by evaporation. Alternatively or additionally, the binder solvent is separated by separating the binder, for example, by lowering the temperature and subsequent filtration, centrifugation, or sedimentation. The binder is removed and the remaining binder solvent is reused to wash the binder or removed.

[0063] After washing of the binder, the ground material or black mass is preferably dried. Drying is preferably carried out at a temperature of up to 80° C. and / or up to 300 hPa, in particular up to 100 hPa, most preferably up to 50 hPa. Since the fluorine content in the ground material or black mass is often significantly lower after removal of the binder, drying can also be carried out at higher temperatures without forming excessive amounts of hydrogen fluoride.

[0064] It is preferred that no water is added when washing off the binder. It is preferred that no water and / or aqueous liquids are added to the ground material until the binder has been removed.

[0065] According to a preferred embodiment, the conductive salt or hexafluorophosphate compound is washed with an aqueous washing solvent, preferably after washing with the conductive salt solvent and / or after washing with the binder.

[0066] 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 basic. Preferably, the pH is 8 or higher. For example, the washing solvent contains ammonia or an ammonium compound.

[0067] Many rechargeable batteries contain a mixture of graphite and metal compound particles, such as NMC (nickel manganese cobalt) particles. These may be bonded together using a binder. By removing the binder, the adhesion between the graphite and the metal compound particles is reduced to such an extent that the graphite can be separated from the metal compound particles much more easily. The graphite fraction may then be separated from the metal compound particle fraction, for example by classification or flotation. Classification may be a fine classification process using a classifier wheel.

[0068] The classifier wheel may also be referred to as a sizing wheel. The classifier wheel has recesses, in particular slots. The recesses preferably have a gap width, in particular a slot width, of 0.1 mm or more, in particular 1 mm or less, and / or 25 mm or less, in particular 15 mm or less, particularly preferably 10 mm or less.

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

[0070] Suitably, the recess and the number of revolutions 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 less than 20 μm.

[0071] Alternatively or additionally, the recess and the number of revolutions are selected so 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, more than 50% of the particles have a particle size of less than 25 μm, in particular less than 20 μm. It has been found that in this way, particularly high concentration factors can be achieved. The particle size is determined according to DIN ISO13320:2009.

[0072] In the graphite fraction, graphite is enriched by a factor of at least 2, preferably at least 3, more preferably at least 4, relative to the metal compound particle fraction, i.e. the concentration of graphite in the graphite fraction is 2, 3 or 4 times higher than in the metal compound particle fraction.

[0073] The production of a graphite fraction, which can be carried out for example by sulfuric acid, is possible but in many cases is not necessary.

[0074] According to a preferred embodiment, at least one metal component is extracted from the metal compound particle fraction by hydrometallurgical means, which may be carried out by means of a mineral acid, such as sulfuric acid, for example concentrated sulfuric acid.

[0075] However, it is not essential that the conductive salt solvent, especially the high boiler fraction, is washed off before separation of the plastic foil portion. Thus, according to one embodiment, the process comprises the following steps: (a) drying the ground material at a temperature of 80° C. or less and a pressure of 300 hPa or less, in particular 100 hPa or less, most preferably 10 hPa or less. The product thus obtained may be called dried ground material. Then follows: (b) Separating the plastic components, in particular the plastic foil fraction, and / or the metal foil fraction. In particular, these components are separated from the dried ground material. The product thus obtained may be called black mass. Then follows: (c) Removing the binder and high boiler fractions with a binder solvent. The pressure and temperature ranges and the use of a suitable binder solvent described above also apply to this embodiment.

[0076] Surprisingly, it has been found that the use of more binder solvent results in less hydrogen fluoride formation, even at temperatures above 80° C., for example. Therefore, at least 1 liter, preferably at least 2 liters, particularly preferably at least 3 liters of binder solvent is added per kilogram of black mass.

[0077] The removal of the binder and the high boiler fractions can be carried out in a batch operation. In this case, the process preferably comprises (a) adding a binder solvent, in particular the above-mentioned amount of binder solvent, to the black mass. The mixing of the binder solvent with the black mass can be accelerated to better dissolve the binder. This acceleration is the introduction of mechanical energy. For example, the acceleration includes stirring, vibration and / or ultrasonication.

[0078] In a subsequent step (b), the binder solvent mixture is removed, for example by filtration, suction, centrifugation or by the introduction of a fluid, which may for example be the binder solvent.

[0079] Steps (a) and (b) are preferably repeated at least once, in particular 2, 3, 4 or more times.

[0080] Alternatively or additionally, removal of the binder and high boiler fraction may be carried out continuously, in which case binder solvent is continuously added and the binder / solvent mixture is removed.

[0081] When the binder solvent is regenerated as described in the preferred embodiment, the high boiler fraction of the conductive salt solvent is also separated in addition to the binder. Regeneration is preferably performed by vacuum distillation.

[0082] After washing the binder, the conductive salt is preferably washed and / or the graphite fraction is separated from the metal compound particle fraction, as described above. For example, after washing the binder, flotation is performed so that the conductive salt or its anion is washed and the graphite fraction is separated from the metal compound particle fraction. The flotation is preferably performed with an aqueous flotation liquid.

[0083] The rechargeable battery processing system according to the present invention may also be called a rechargeable battery recycling system or a rechargeable iontophoretic reprocessing system. The rechargeable battery processing system according to the present invention is designed to carry out the process according to the present invention. Preferably, for each of the preferred process steps described above, there is an apparatus designed to carry out this process step.

[0084] The separation device comprises, for example, a classifier, in particular a fine or air classifier, or a flotation plant, for example a froth flotation plant.

[0085] The binder leaching device preferably comprises a recovery plant for recovering the binder solvent, for example a Nutsche filter, a filter or a distillation device, in particular a vacuum distillation device, which is reused to wash the binder.

[0086] The rechargeable battery treatment system preferably has a heavy boiler fraction washing device arranged in the material flow direction before the binder washing device and after the rechargeable battery grinding system and designed to wash the heavy boiler fraction of the conductive salt solvent of the rechargeable battery with a heavy boiler fraction solvent, thereby obtaining a heavy boiler / solvent mixture and a ground material with less heavy boiler.

[0087] If the rechargeable battery treatment system is designed to wash the high boiler fraction and binder in separate steps, as described in the preferred embodiment, the high boiler fraction washing device is preferably located before the dryer and before the plastic separator in the material flow direction.

[0088] It is advantageous for the rechargeable battery processing system to have a regeneration device for regenerating the high boiler fraction solvent. In particular, the regeneration device is also designed to separate the high boiler fraction. The regeneration device can be, for example, a distillation device, in particular a vacuum distillation device. The regenerated high boiler fraction solvent is reused for cleaning. In other words, the high boiler fraction solvent is recycled. The excess high boiler fraction solvent is removed and used, for example, in the manufacture of new rechargeable batteries.

[0089] The present invention will now be described in detail with reference to the accompanying drawings. [Brief description of the drawings]

[0090] [Figure 1] FIG. 1 shows a flow diagram of a process according to the present invention according to a first embodiment. [Diagram 2] FIG. 2 shows a flow diagram of the process according to the present invention according to a second embodiment. [Diagram 3] FIG. 3 shows a flow diagram of the process according to the present invention according to a third embodiment. [Figure 4] 4 shows a flow chart of the method according to the present invention according to a fourth embodiment. [Diagram 5] 1 shows a schematic diagram of a rechargeable battery processing system according to the present invention; DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0091] FIG. 1 shows a flow diagram of the process according to the invention and a schematic structure of a rechargeable battery treatment system 8 according to the invention. First, the rechargeable battery to be recycled, shown as a rechargeable battery 10 composed of galvanic elements 12.i (i=1, 2, . . . ), is short-circuited in step S1 by a discharger 14. For that purpose, the negative pole 15.1 and the positive pole 15.2 are connected to each other by a discharger preferably having a resistance of less than 10 Ohms. The discharge is performed in such a way that the galvanic elements 12.i are connected to each other by a discharger 14 having a resistance of U reg = Regenerated cell voltage U below 0.3V reg The process ends only if the

[0092] The rechargeable battery 10 is then crushed in a rechargeable battery crushing system 16 according to step S2 to obtain crushed material 18. The crushed material 18 travels from the crushing plant 16, preferably through a dust-proof conduit 20, to a high boiler fraction washer 22. In the high boiler fraction washer 22, the conductive salt solvent, in particular the high boiler fraction 24, is washed according to step S3. For that purpose, a high boiler fraction solvent 26 is added to the crushed material 18. The high boiler fraction solvent washer 22 can, but does not have to, have a circulation device, for example an agitator.

[0093] The high boiler fraction solvent 26 may be, for example, a conductive salt solvent that dissolves a conductive salt in the rechargeable battery 10. The conductive salt solvent and conductive salt solution form the electrolyte of the rechargeable battery 10.

[0094] The high boiler fraction solvent 26 dilutes the electrolyte of the rechargeable battery 10 to provide a high boiler fraction of itself, i.e., a separation boiling point T S,t Enrich the conductive salt solvent with a boiling point above T. S,t = 150°C.

[0095] For example, the high boiler fraction wash apparatus 22 includes a vessel 28 in which the ground material 18 is mixed with a high boiler fraction solvent 26. This produces a high boiler / solvent mixture 30 that can be fed to a regenerator 32. In the regenerator 32, the high boiler fraction solvent 26 is separated from the high boiler fraction 24, for example by vacuum distillation. In this manner, a ground material 18' having a reduced high boiler content is obtained.

[0096] The ground material 18' with a low high boiler content is fed through a particularly dust-tight, preferably airtight, line 34 to a dryer 36. In step S4, the low boiling ground material 18' is dried at a temperature below 80° C., in this case 50° C., for example under a pressure of 50 hPa. Drying is optional.

[0097] After drying, the dried ground material 18″ moves into an optional plastic separator 38 where the plastic components 40 are separated according to optional step S5. The plastic components 40 may be, for example, part of a plastic housing or part of a plastic film, in particular a separator film. Also preferably, the metal foil portion is separated.

[0098] In this way, a black mass 42 is obtained.

[0099] The black mass 42 moves into a binder washer 44 where a binder solvent 46 is added to the black mass 42. The binder solvent 46 may be, for example, dimethyl sulfoxide. 48 is preferably T 48 = 80°C. A binder solvent mixture 50 is produced by washing the binder from the black mass 42 according to step S6 using the binder solvent 46. The binder / solvent mixture 50 is either discarded or fed to a recovery system 52 which separates the binder solvent 46 from the binder 54 using filtration and / or distillation.

[0100] Optionally, in a subsequent step S7, the binder solvent 46 can be washed off by an auxiliary solvent 56. This is done, for example, in a vessel 58, but may also be done in a washing vessel 48.

[0101] The co-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 T56 of the co-solvent 56 is less than 120° C., in particular less than 100° C., and particularly preferably less than 80° C. at standard pressure. The co-solvent 56 is added to the low-binder black mass 42′ to produce a mixture 60. The co-solvent 56 and the binder solvent 46 are separated from each other, for example by a distillation apparatus 62.

[0102] It is possible to use conductive salt solvent substances, especially low boiling fractions, as binder solvent 46. In this case, the temperature T48 is preferably above T48=80° C., for example T48≧100° C. In order to clean the binder 54 as efficiently as possible, a high temperature is advantageous. Thus, in one embodiment, cleaning of the binder 54 is performed at positive pressure, so that cleaning can take place at a temperature above the boiling point of the binder solvent. For example, the pressure p in the cleaning vessel 48 is 100° C. 48 p 48 ≧1500hPa.

[0103] In an optional step S8, the black mass 42' is dried. This is preferably done at a temperature below 80° C. and at a pressure below 300 hPa, for example below 100 hPa. A dryer 36 may be used for this purpose.

[0104] Thereafter, in an optional conductive salt washing system 64, according to optional step S9, the conductive salts or the anions of the conductive salts are washed from the black mass 42' by an aqueous liquid 66. In this way, a black mass with a low fluorine content and in particular a low binder content is obtained.

[0105] Due to the low binder content, the graphite fraction 70 of the black mass 42' can be easily separated from the metal compound particle fraction 72 in the separator 68 in step S10. The metal compound particle fraction 72 is composed of particles enriched with metal compounds. For example, NMC (nickel manganese cobalt) particles are enriched in the metal compound particle fraction 72.

[0106] The metal components of the metal compound particle fraction 72 are preferentially hydrometallurgically extracted, for example by precipitation or solvent extraction.

[0107] FIG. 2 shows a schematic diagram of a rechargeable battery treatment system 8 and method according to the invention. After the short circuit according to step S1, at least one rechargeable battery 10 is ground in step S2 to form a ground material 18. This is dried in a dryer 36. The plastic component 40, in particular the plastic foil portion and / or the metal foil portion, is then separated to obtain a black mass 42. The conductive salt solvent, in particular the high boiler fraction, is then washed from the black mass 42. The binder is then washed. Optionally, the binder solvent is then washed. The black mass is then dried and the conductive salt is washed with an aqueous liquid. The graphite fraction 70 and the metal compound particle fraction 72 are then separated again.

[0108] 3 shows a schematic diagram of a rechargeable battery processing system 8 and method according to the present invention, in which after short-circuiting and crushing of the rechargeable battery, the conductive salt solvent, especially the high boiler fraction, is first washed off, and then the crushed material is dried so that the plastic part 40 can be more easily separated in the subsequent step.

[0109] The resulting black mass 42 is then washed of the conductive salts using an aqueous liquid, and the black mass 42 is optionally dried. Since the black mass 42 is then substantially free of the conductive salts, drying can be performed at a drying temperature of more than 100° C., which evaporates the aqueous liquid. The binder is then washed, and optionally the binder solvent is removed by washing. After drying, the graphite fraction 70 can be separated from the metal compound particle fraction 72.

[0110] 4 shows a schematic diagram of a rechargeable battery processing system 8 and method according to the invention, in which after short-circuiting of the rechargeable battery and grinding and drying of the ground material, the plastic parts, in particular the plastic foil parts and / or the metal foil parts, are separated. The conductive salt solvent is then washed, followed by drying of the black mass. The conductive salt is then washed, optionally the black mass is dried, followed by washing of the binder. Optionally, the binder solvent is then washed, optionally dried, followed by separation of the graphite fraction 70 and the metal compound particle fraction 72.

[0111] Figure 5 shows a further embodiment of the process according to the invention, in which at least one rechargeable battery is comminuted after discharging, optionally short-circuiting according to step (a) of claim 1. The comminuted material 18 is then dried and the plastic foil portion is separated from the thus obtained dry comminuted material. Drying is preferably performed at a pressure of 300 hPa or less, in particular 100 hPa or less, preferably 10 hPa or less. The temperature during drying is preferably 70°C or less, in particular 60°C or less, preferably 50°C or less.

[0112] The binder and the conductive salt solvent are then washed together. This can be done, for example, with the low boiling fraction of the conductive salt solvent of the rechargeable battery at 70° C. or higher, preferably 80° C. or higher, particularly preferably 90° C. or higher, in particular 100° C. or higher, for example 110° C. or higher. 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 1.5 bar or higher, in particular 2 bar or higher, for example 3 bar or higher. The pressure is usually less than 150 bar, in particular less than 100 bar. Alternatively, the binder and the conductive salt solvent are washed with an organic solvent that is not part of the conductive salt solvent, for example with dimethyl sulfoxide.

[0113] The black mass can then be dried, but this is not essential. In a subsequent step, the conductive salt is washed with an aqueous liquid. The graphite fraction and the metal compound particle fraction are then separated from each other. [Explanation of symbols]

[0114] 8 Rechargeable Battery Treatment System 10 rechargeable batteries 12 Galvanic Cell 14 Discharger 16 Rechargeable Battery Crushing System 18 Crushed materials 20 Conduit 22 High boiler fraction cleaning device 24 High boiler fraction 26 High boiler fraction solvent 28 Container 30 High boiler / solvent mixture 32 Playback device 34 Line 36 Dryer 38 Plastic Separator 40 Plastic Components 42 Black Mass 44 Binder Cleaning Equipment 46 Binder Solvent 48 Cleaning container 50 binder / solvent mixture 52 Collection System 54 Binder 56 Co-solvents 58 Container 60 mixture 62 Distillation Unit 64 Conductive Salt Cleaning System 66 Aqueous liquid 68 Dryer 70 Graphite Fraction 72 Metal Compound Particle Fraction T S,t separation boiling point T k Short circuit time U reg Regeneration cell voltage

Claims

1. A method for recycling rechargeable batteries (10), in particular lithium rechargeable batteries (10) and / or sodium rechargeable batteries, each consisting of at least one galvanic element, each having two poles and containing a conductive salt dissolved in a conductive salt solvent, comprising: (a) shorting the rechargeable battery (10) until at least 75% of the galvanic elements have a regenerated cell voltage of 0.3 volts or less, in particular 0.2 volts or less; (b) thereafter, grinding said rechargeable battery (10) to obtain ground material (18); A method for providing the above.

2. (a) washing the conductive salt solvent with a high boiler fraction solvent (26), in particular with a low boiler fraction of said conductive salt solvent; (b) the cleaning is carried out at a temperature of 80° C. or less; The method of claim 1 , comprising:

3. (a) drying the ground material (18) at a temperature of not more than 80° C. and a pressure of not more than 300 hPa, after washing off the conductive salt solvent, so as to obtain the ground material having a low content of high boilers; (b) separating the plastic component (40) of the low high boiler content ground material (18); Method according to one of claims 1 to 2, characterized in that it comprises:

4. After washing away the conductive salt solvent, removing the binder (54) with a binder solvent (46); The method according to one of claims 1 to 3, characterized in that it comprises:

5. (a) the binder solvent (46) is composed of at least 50 weight percent of materials that are components of the conductive salt solvent; and / or (b) the washing of the binder (54) is carried out at a temperature of 80° C. or higher, in particular at a temperature of 90° C. or higher; The method according to claim 4, characterized in that

6. washing the conductive salt with an aqueous washing solvent after removal of the binder (54); The method according to one of claims 1 to 5, characterized in that it comprises:

7. - separating the graphite and metal compound particle fractions after removal of said binder (54), in particular after washing of the conductive salts; The method according to one of claims 1 to 6, characterized in that it comprises:

8. (a) drying the ground material (18) at a temperature of not more than 80° C. and a pressure of not more than 300 hPa (to obtain a dried ground material (18)); (b) thereafter separating the plastic component (40) so as to obtain a black mass (42); (c) thereafter removing the binder (54) and the high boiler fraction (24) with said binder solvent (46); The method according to one of claims 1 to 7, characterized in that it comprises:

9. (a) a rechargeable battery grinding system (16) for grinding a rechargeable battery (10) to obtain a grinding material (18); (b) a binder washing device arranged downstream of the rechargeable battery grinding system (16) in a material flow direction and designed to wash the binder (54) from the ground material (18) by means of a binder solvent (46) so as to obtain ground material (18) having a low content of high boilers; (c) a separation device designed to separate a graphite fraction from a metal compound particle fraction (72) of said ground material (18); A rechargeable battery treatment system (8).

10. (a) a high boiler fraction washing device (22) arranged upstream of the binder washing device (44) and downstream of the rechargeable battery grinding system (16) in the material flow direction, designed for washing a high boiler fraction (24) of a conductive salt solvent of the rechargeable battery (10) with a high boiler fraction solvent (26) so as to obtain a high boiler / solvent mixture (30) and a ground material (18) having a low high boiler content; (b) the high boiler fraction wash apparatus (22) has a regeneration apparatus (32) for regenerating the high boiler fraction solvent (26); A rechargeable battery treatment system (8) according to claim 9, characterized in that

11. (a) a dryer (36) arranged downstream of the high boiling fraction wash unit (22) in the material flow direction; (b) a plastic separator (38) arranged downstream of the dryer (36) and upstream of the binder washing device for separating plastic parts, in particular plastic foil parts; 11. A rechargeable battery treatment system (8) according to claim 10, characterized in that it comprises:

12. 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 the conductive salt with an aqueous liquid; A rechargeable battery treatment system (8) according to one of claims 9 to 11, characterized in that it comprises:

13. (a) a dryer (36) arranged downstream of the rechargeable battery crushing system (16) in the material flow direction and designed for drying at a temperature of not more than 60° C. and a pressure of not more than 300 hPa; (b) a plastic separator (38) arranged downstream of the dryer (36) and upstream of the binder washing 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 conductive salts; 10. A rechargeable battery treatment system (8) according to claim 9, characterized in that it comprises:

14. a wet-chemical processing system arranged downstream of the separation device in the material flow direction for wet-chemically extracting at least one metal component from the metal compound fraction; A rechargeable battery treatment system (8) according to one of claims 9 to 13, characterized in that it comprises:

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