Method for recycling alkali metal batteries and battery processing system

Abstract

The invention relates to a method for recycling alkali metal batteries (12), in particular Li batteries or Na batteries, which have an active material, a carrier foil on which the active material is arranged, binder by means of which the active material is bound to the carrier foil, a liquid electrolyte, conducting salt (38) and a housing that encloses the active material, carrier foil and binder, with the step of comminuting the alkali metal batteries (12) such that the comminuted material, the black matter (30), which contains the active material and the binder, is produced, with the steps of washing the comminuted material with a washing solvent (36) such that conducting salt (38) is washed out and the binder is not washed out such that low- conducting-salt comminuted material and a washing liquid (40) are obtained, regenerating the washing solvent (36) from the washing liquid (40), and in particular by distilling, and washing the comminuted material with at least some of the regenerated washing solvent (36). The invention also relates to a battery preparation system for recycling alkali metal batteries (12), in particular Li batteries or Na batteries.

Description

[0001] Process for recycling alkali metal batteries and battery processing plant

[0002] The invention relates to a method for recycling alkali metal batteries, in particular Li batteries or Na batteries, which comprise (a) an active material, in particular graphite or silicon, (b) a carrier foil on which the active material is arranged, (c) a binder with which the active material is bonded to the carrier foil, (d) an electrolyte, in particular a liquid one, and (e) a conductive salt. The alkali metal battery preferably also comprises a housing, but it can also be housing-free. The method comprises the step of comminuting the alkali metal batteries to produce comminution material containing the active material and the binder.

[0003] According to a second aspect, the invention relates to a battery processing plant for recycling alkali metal batteries, in particular Li batteries or Na batteries, comprising (a) a comminution plant for comminuting the alkali metal batteries.

[0004] Alkali metal batteries are being used extensively and increasingly to power electrical devices. In particular, alkali metal batteries are used as traction batteries in electric vehicles. Electric vehicles are being increasingly used because they can lead to fewer CO2 emissions during use. To reduce the carbon footprint of electric vehicles, the most efficient and resource-saving recycling of alkali metal batteries is desirable.

[0005] CN 103 825 064 A describes a process in which the electrolyte is washed out of intact batteries. After distilling the electrolyte, a portion of the distillate is reused to wash out the electrolyte. After removing the electrolyte, the housing is sawn open at the top, and the electrodes are removed. The electrodes are unwound and separated into the positive electrode, separator, and negative electrode. Such a process is complex and technically very demanding, especially when processing a large number of differently constructed batteries.

[0006] CN 110 380 150 A describes a process in which the battery is first disassembled. The electrolyte is then washed out using an organic solvent and an organosiloxane, and the resulting mixture is heated so that the conductive salt reacts with the organosiloxane and precipitates. This makes recovery of the conductive salt difficult.

[0007] A process is known from CN 113 322 380 A in which batteries are discharged and crushed. The electrolyte is separated from the crushed material by filtration and mixed with lime milk, so that fluorine components precipitate as calcium fluoride.

[0008] WO 2014 / 208597 A1 describes a process in which the electrolyte is washed out of intact batteries. The resulting solution is mixed with water or acid and evaporated under vacuum, so that fluorine components are expelled as hydrogen fluoride.

[0009] The invention is based on the object of improving the recycling of alkali metal batteries.

[0010] The invention solves the problem by a generic method comprising the steps of (ii) washing the comminution material with a washing solvent so that conductive salt is washed out and the binder is not washed out, so that comminution material with a low content of conductive salt and a washing liquid are obtained, (iii) regenerating the washing solvent from the washing liquid and (iv) washing the comminution material with at least a portion of the regenerated washing solvent.According to a second aspect, the invention solves the problem by a generic battery processing plant having (b) a washing device which is designed and arranged to wash at least a fraction of the comminution material, in particular black mass, with a washing solvent, so that comminution material low in conductive salt and a washing liquid are obtained, and (c) a regenerator which (i) is designed to automatically regenerate washing solvent from the washing liquid, (ii) a supply line which is connected to the washing device for conducting washing liquid from the washing device to the regenerator, and (iii) a return line which is connected to the washing device for conducting washing solvent from the regenerator to the washing device.

[0011] An advantage of the invention is that the conducting salt can usually be recovered on a large scale. The recovered conducting salt can be reused in alkali metal batteries. For this purpose, it may be advantageous to separate the conducting salt from the washing liquid or a fraction of the washing liquid. It may also be advantageous to subsequently purify the conducting salt, for example, by crystallization and / or refining.

[0012] Preferably, the washing of the comminution material and / or the regeneration of the washing solvent is carried out such that the at least one conducting salt and / or the anion of the at least one conducting salt or the anions of the at least one conducting salt remain unchanged to an extent of at least 50 mol%, in particular at least 70 mol%, in particular at least 80 mol%, preferably at least 90 mol%, particularly preferably at least 95 mol%, and is particularly separated during regeneration. For example, preferably so little water and / or so little acid is added to the electrolyte and / or the comminution material that the conducting salt and / or the anion of the conducting salt remains unchanged to an extent of at least 80 mol%, preferably at least 90 mol%, particularly preferably at least 95 mol%.

[0013] Another advantage is that the process can generally be carried out, and according to a preferred embodiment, is carried out, in such a way that essentially no hydrogen fluoride is formed during the washing out of the conducting salt and / or during regeneration. As a result, according to a preferred embodiment, the fluorine bound in the conducting salt can be recovered to a large extent, preferably to at least 95 percent by weight, in particular at least 97 percent by weight, and particularly preferably at least 99 percent by weight.

[0014] The feature that essentially no hydrogen fluoride is formed is understood in particular to mean that during washing out of the conducting salt and / or during regeneration, at most 5 mol%, in particular at most 2 mol%, preferably at most 1 mol%, particularly preferably at most 0.1 mol%, particularly particularly preferably at most 0.05 mol%, of the fluorine in the alkali metal batteries reacts to form hydrogen fluoride.

[0015] The electrolyte is understood in particular to be a solution of a conducting salt solvent and conducting salt dissolved therein.

[0016] Another advantage is that the electrolyte can often be recovered at a comparatively high level of purity. It has been shown that electrolyte can be recovered at such a high purity that it can be reused for the production of alkali metal batteries, and is used according to a preferred embodiment.

[0017] For the purposes of this description, 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 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.

[0018] 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.

[0019] 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.

[0020] The crushing material is understood to be the material that is created by crushing the alkali metal batteries.

[0021] The term "black mass" refers, in particular, to the graphite- and / or silicon-containing fraction of the comminution material. In particular, black mass contains at least 30 percent by weight, especially at least 40 percent by weight, of graphite. The black mass preferably comprises at least 10 percent by weight of transition metals and / or their compounds. For example, the black mass contains at least 5 percent by weight of nickel and / or 3 percent by weight of cobalt, but this is not necessary. This weight specification refers to the weight of the nickel or cobalt and corresponds to the proportion in weight percent that would be obtained if all nickel or cobalt atoms were present in elemental form, i.e., not in compounds.

[0022] The black mass is, in particular, the material obtained by separating plastic particles, in particular shredded casing and / or shredded separator foils from alkali metal batteries, from the shredded material. A separator foil is understood to be a foil that separates the anode from the cathode.

[0023] Washing the comminution material means that either the comminution material itself or a fraction of the comminution material, in particular the black mass, is brought into contact with the washing solvent in such a way that the conducting salt is at least partially dissolved by the washing solvent. Dissolving the conducting salt converts the washing solvent into the washing liquid.

[0024] The feature that conductive salt is washed out is understood in particular to mean that at least a part, in particular at least half (in mol percent, in particular at least 60 mol percent, particularly preferably at least 70 mol percent, particularly preferably at least 80 mol percent, particularly preferably at least 90 mol percent), of the anions of the conductive salt are removed. The regeneration of the washing solvent from the washing liquid is understood in particular to mean that the washing liquid is treated in such a way that washing solvent is obtained again. In particular, the regeneration comprises a separation of conductive salt from the washing solvent.

[0025] The feature that the washing solvent is a component of the electrolyte is understood in particular to mean that it is the same substance. Preferably, at least a portion of the washing solvent was previously contained in an alkali metal battery that was comminuted during the process. At the beginning of the process according to the invention, washing solvent is preferably used that is not contained in an alkali metal battery or was contained and recovered. During the course of the process, conductive salt solvent is washed out of the comminution material and partially regenerated as washing solvent. Since preferably a portion of the conductive salt solvent is removed during regeneration, the proportion of conductive salt solvent in the washing solvent increases continuously.

[0026] In other words, the crushing material is preferably washed with a component of its own conducting salt solvent.

[0027] Comminution is understood, in particular, as comminution in the sense of mechanical process engineering. In particular, comminution is understood to mean shifting the object size distribution into a finer size range. Comminution is, in particular, an irreversible reduction in the size of the object, for example, alkali metal batteries. Comminution is, in particular, a breaking down of the material bond of the object, which does not occur along a joint. In particular, comminution is not disassembly.

[0028] The comminution is preferably (a) pressure comminution, in which the object is crushed between two tool surfaces, (b) impact comminution, in which the object rests on a tool surface and is shattered by impact with a second movable tool, (c) friction comminution, in which the object is stressed by two oppositely moving tool surfaces, (d) cutting comminution, in which the object is cut into two parts by means of at least two cutting edges and / or (e) impact comminution, in which the object is thrown against a wall, bounces against a moving tool or in which two objects are brought into collision.

[0029] Comminution, in particular cutting and comminution, has the advantage that the proportion of very small plastic particles created during comminution of the housing is comparatively low. Cutting and comminution is preferably carried out in such a way that the weight proportion (in pieces, i.e., in particular not in weight percent) of plastic particles created during comminution of the housing with a weight less than one-tenth of the median weight of the plastic particles created during comminution of the housing amounts to at most one-third, in particular at most one-tenth, of the weight proportion of plastic particles created during comminution of the housing and having a weight above the median weight. Machining and comminution processes, such as sawing, produce many small plastic particles that are often difficult to separate in the subsequent process.

[0030] Comminution is preferably carried out using a solid comminution tool. This has the advantage of reducing contamination of the comminution material. Using a liquid comminution tool, such as water in waterjet cutting, will result in contamination of the comminution material.

[0031] Preferably, at least half (in weight percent), in particular at least 90 weight percent, of the electrodes are severed during comminution.

[0032] Cutting the electrodes typically results in the mixing of materials that were previously separated in the battery, particularly the cathode and anode coatings. However, it has surprisingly been found that such extensive separation of the individual components is possible that the mixing is a tolerable disadvantage.

[0033] During comminution, at least half (in number), in particular at least 90 percent, of the carrier films and / or the separator films are preferably severed, in particular cut, at least once. Smaller carrier film particles are heavier than the other components of the comminution material. In particular, the comminution material contains both crushed electrodes and particles of crushed housing and / or crushed separator film. The housing is the structure that surrounds the electrodes and shields them from the environment. The housing is preferably crushed using the same comminution system and / or at the same time as the other components of the alkali metal battery. The housing and the carrier film are preferably crushed simultaneously, i.e. using the same tool and at the same time.In particular, the housing and the carrier film are cut, whereby both the housing and / or the separator film and the carrier film are cut during the cutting processes.

[0034] Alternatively or additionally, the regeneration may, for example, comprise separating the conducting salt by lowering the temperature.

[0035] The feature of washing the comminution material with at least a portion of the regenerated washing solvent means that the regenerated washing solvent is at least partially recombined with the comminution material to wash out the conductive salt. In other words, the washing solvent is at least partially recirculated.

[0036] Preferably, the comminution material is washed with the washing solvent at a temperature of at most 80°C, in particular at most 70°C, preferably at most 60°C, particularly preferably at most 55°C, particularly preferably at most 50°C, particularly preferably at most 45°C, particularly at most 40°C. Although low temperatures slow the leaching of the conductive salt, they significantly reduce the decomposition of the conductive salt and / or the formation of hydrogen fluoride.

[0037] The electrolyte contains a conducting salt solvent for dissolving the conducting salt. The conducting salt solvent can be a pure substance. Alternatively, the conducting salt solvent is a mixture of at least two pure substances. The electrolyte also contains the conducting salt. The electrolyte is understood to be a liquid or solid containing ions, namely those of the conducting salt.

[0038] A conducting salt is a compound composed of an anion and a cation, dissolved in the conducting salt solvent. The anion is typically an alkali metal anion, which is released or absorbed by the cathode and / or by the anode during charging and discharging. Alkali metal batteries may contain multiple substances that act as a conducting salt. In this case, the conducting salt refers to the sum of all these substances.

[0039] The conducting salt solvent preferably contains ethyl methyl carbonate, i.e. ethyl methyl carbonate (EMC), and / or dimethyl carbonate, i.e. dimethyl carbonate (DMC).

[0040] If—as provided in a preferred embodiment—the comminution material is washed in batch operation, the comminution material is preferably washed at least twice, in particular at least three times, preferably at least four times, in particular at least five times, each time with a new washing solvent. Preferably, the washing is carried out no more than one thousand times.

[0041] It has been found that washing at least once often leads to unsatisfactory purities of the recovered graphite and / or conductive salt.

[0042] If - as provided according to an alternative preferred embodiment - the comminution material is washed continuously or semi-continuously, the washing solvent is preferably supplied in such a way that at the end of the washing, a concentration of conductive salt in the washing solvent is as high as it would be if the comminution material had been washed at least twice, in particular at least three times, preferably at least four times, in particular at least five times, each time with new washing solvent in batch operation.

[0043] According to a preferred embodiment, the method comprises the step of separating the black mass from a residual fraction, in particular by sifting or sieving. The black mass obtained is preferably washed with the washing solvent. Alternatively or additionally, the separation of the black mass can also comprise froth flotation. Again alternatively or additionally, the separation can comprise preparing a suspension and centrifuging the suspension. Since black mass should consist of as high a proportion as possible of graphite, with which the anode is usually coated, this graphite usually consists of particles that are small compared to the particles of the housing and / or the carrier film, sieving, in particular air jet sieving, has proven advantageous.

[0044] The step of separating the black mass from the residual fraction is carried out on the, in particular dried, comminution material. The residual fraction is the material remaining after the black mass has been separated. In particular, the residual fraction and the black mass form the, in particular dried, comminution material. The residual fraction preferably contains particles of comminuted casing and / or comminuted separator foils and / or particles of comminuted carrier foils.

[0045] Preferably, the separation of the black mass from the residual fraction is carried out in such a way that the plastic weight fraction of plastic particles in the black mass amounts to at most one-fifth of the plastic weight fraction in the residual fraction. This ensures that when washing the shredded material, especially the black mass, the washing solvent comes into little or no contact with plastic, i.e., plastic or paper. The otherwise frequently occurring swelling of the plastic and / or contamination of the washing solvent with plastic or plastic components is avoided. Swelling can make plastic stickier, making it more difficult to separate the black mass from the plastic after washing.

[0046] In particular, the separation of the black mass from the residual fraction includes or is a separation of the black mass from plastic particles. The plastic particles include, in particular, particles that were created during the comminution of the alkali metal batteries by crushing the casing.

[0047] The separation of the comminution material, in particular the black mass, from the washing solvent takes place, for example, by filtering. Therefore, a process comprising the steps of (i) comminution of the alkali metal batteries to produce comminution material containing black mass, active material, and binder, (ii) subsequent separation of the black mass, in particular by sifting or sieving, from the comminution material, (iii) washing the black mass of the comminution material with a washing solvent to remove the conductive salt and not remove the binder, thus obtaining a low-conductive salt black mass and a washing liquid, (iv) regenerating the washing solvent from the washing liquid, in particular by distillation, and (v) washing the black mass with at least a portion of the regenerated washing solvent. In this way, the conductive salt can generally be recovered with particularly high purity.The preferred embodiments mentioned in this description also apply to this invention. This method preferably comprises the steps mentioned for the other methods according to the invention.

[0048] The washing solvent is preferably a component of the electrolyte. The washing solvent preferably consists of at least 50 percent by weight, preferably at least 70 percent by weight, more preferably at least 85 percent by weight, especially preferably at least 95 percent by weight, and particularly preferably at least 98 percent by weight, of a compound or compounds that are a component of the electrolyte.

[0049] It is advantageous if the washing solvent contains at least substantially no thinner. This means, in particular, that no more than 20 percent by weight, in particular no more than 15 percent by weight, particularly preferably no more than 10 percent by weight, and preferably no more than 5 percent by weight of the washing solvent consists of substances that are not simultaneously present in the electrolyte of the alkali metal batteries.

[0050] It is advantageous if the washing solvent is essentially not brought into contact with water. The feature that the washing solvent is essentially not brought into contact with water is understood in particular to mean that contact with water that leads to a reaction of at least 5 mol%, in particular more than 1 mol%, particularly preferably more than 0.1 mol%, of the conducting salt does not occur. In particular, no water is added to the washing solvent.

[0051] It is advantageous if the washing solvent contains at least two different solvents. This increases the solubility of the conducting salt.

[0052] The washing solvent preferably contains at least 5 weight percent, in particular at least 10 weight percent, more preferably at least 15 weight percent, more preferably at least 20 weight percent, most preferably at least 25 weight percent, of a first pure substance (first washing solvent pure substance) and at least 5 weight percent, in particular at least 10 weight percent, more preferably at least 15 weight percent, more preferably at least 20 weight percent, most preferably at least 25 weight percent, of a second pure substance (second washing solvent pure substance). The first pure substance is preferably ethyl methyl carbonate. The second pure substance is preferably dimethyl carbonate.

[0053] Preferably, a washing solvent main component concentration of the main component of the washing solvent (measured in percent by weight) deviates from a conducting salt solvent main component concentration of the main component of the conducting salt solvent by a factor of at most 10, in particular a factor of at most 9, in particular a factor of at most 8, in particular a factor of at most 7, in particular a factor of at most 6, in particular a factor of at most 5, in particular a factor of at most 4, in particular a factor of at most 3, in particular a factor of at most 2.

[0054] The factor is calculated by determining the maximum from the amount containing the concentration of the main component of the washing solvent and the concentration of the main component of the conducting salt solvent. The factor is the quotient of this maximum (as the numerator) and the minimum of the specified amount (as the denominator). The main component is the pure substance that has the largest proportion by weight of the washing solvent or the conducting salt solvent. The conducting salt solvent is optimized to dissolve the conducting salt as well as possible. The washing solvent is therefore generally able to dissolve the conducting salt particularly well if its main component matches the main component of the conducting salt solvent as closely as possible.

[0055] Preferably, the concentration of the secondary main component of the washing solvent (measured in percent by weight) differs from the concentration of the secondary main component of the conducting salt solvent by a factor of at most 10, in particular by a factor of at most 9, in particular by a factor of at most 8, in particular by a factor of at most 7, in particular by a factor of at most 6, in particular by a factor of at most 5, in particular by a factor of at most 4, in particular by a factor of at most 3, in particular by a factor of at most 2. The secondary main component is the pure substance that has the second-largest proportion in the washing solvent or the conducting salt solvent in percent by weight. This further improves the solubility of the conducting salt in the washing solvent.

[0056] Preferably, the washing solvent is chosen so that it does not react with the conductive salt during washing.

[0057] Preferably, the washing solvent is selected so that it does not form a compound with lithium during washing.

[0058] Preferably, when washing the comminution material, in particular the black mass, the comminution material, in particular the black mass, is moved, for example stirred or rotated in a rotatable drum.

[0059] Washing can be carried out continuously, discontinuously (i.e. in batch mode) or semi-continuously.

[0060] The washing of the comminution material, in particular the black mass, is preferably carried out until at least 70 percent by weight, in particular at least 75 percent by weight, in particular at least 80 percent by weight, in particular at least 85 percent by weight, in particular at least 90 percent by weight, in particular at least 95 percent by weight, of the conductive salt has been removed. This can be determined, for example, by taking samples of the comminution material, in particular the black mass, at regular intervals and determining the conductive salt content. This can be done, for example, using nuclear magnetic resonance (NMR) measurements.

[0061] Alternatively, the concentration of conducting salt in the washing liquid is continuously monitored, for example, also using (NMR) measurement. This concentration follows an extraction curve in which the concentration of conducting salt is plotted against the total amount of washing solvent used. The extraction curve is strictly monotonically decreasing. The measured values ​​are fitted using a parameterized model function (curve fitting), with the parameters of the model function selected so that the original concentration can be determined from them. From this model function, the concentration at which the specified proportion of conducting salt is removed is calculated. If a measured value is lower than this concentration, the washing process is terminated.

[0062] Alternatively, preliminary tests can be carried out to determine how often and / or for how long washing solvent must be added and removed in order to remove the specified amount of conductive salt.

[0063] According to a preferred embodiment, the regeneration of the washing solvent comprises distilling, in particular vacuum distilling, the washing liquid.

[0064] Vacuum distillation takes place at a regeneration temperature. The regeneration temperature is preferably at most 100°C, in particular at most 80°C, in particular at most 70°C, in particular at most 60°C, in particular at most 55°C, in particular at most 52°C, in particular at most 50°C, in particular at most 48°C, in particular at most 45°C.

[0065] Preferably, the regeneration of the washing solvent is carried out such that the conducting salt, in particular lithium hexafluorophosphate, and / or the anion of the conducting salt, does not decompose and / or does not chemically react to an extent of at least 80 mol%, in particular to an extent of at least 90 mol%. In particular, essentially no calcium compound is added and / or fluorine is not precipitated as calcium fluoride. The feature that essentially no calcium compound is added is understood in particular to mean that at most 5% by weight, in particular at most 1% by weight, particularly preferably at most 0.1% by weight, of a calcium compound is added to the washing solvent.

[0066] Preferably, the regeneration of the washing solvent is carried out in such a way that the conducting salt is recovered. Alternatively or additionally, the regeneration of the washing solvent is carried out in such a way that at least 80 mol%, in particular at least 85 mol%, particularly preferably at least 90 mol%, particularly preferably at least 95 mol%, of the anions of the conducting salt are deposited unchanged in a compound. In other words, a substance is preferably deposited during regeneration that contains the same anion as the conducting salt, but possibly, but not necessarily, a different cation.

[0067] The regeneration temperature is the highest temperature in the vacuum distillator at a point that comes into contact with conductive salt (dissolved or undissolved).

[0068] Vacuum distillation is preferably carried out at a pressure below the vapor pressure of the washing solvent at the regeneration temperature.

[0069] According to a preferred embodiment, the distillation pressure p42 is selected such that both ethyl methyl carbonate (EMC, ethyl methyl carbonate) and dimethyl carbonate (DMC, dimethyl carbonate) evaporate.

[0070] Preferably, the distillation pressure p42 is selected so that no substances evaporate whose boiling point at atmospheric pressure (1013 hPa) lies above a cut-off boiling point Tsepar. Substances with a boiling point that corresponds at most to the cut-off boiling point Tsepar are called low-boiling substances.

[0071] The higher the separation boiling point Tsepar, the more components of the alkali metal battery electrolyte are part of the washing solvent. The separation boiling point Tsepar is preferably chosen so that a maximum of five components, in particular a maximum of four components, preferably a maximum of three components, and particularly preferably a maximum of two components, of the electrolyte evaporate.

[0072] Preferably, the separation boiling point Tsepar is chosen so that at least one component, in particular at least two components, preferably at least three components, particularly preferably at least four components, of the electrolyte evaporate.

[0073] One component of the electrolyte is a pure substance whose proportion in the electrolyte of the alkali metal batteries is at least 0.5 mol%.

[0074] Preferably Ttrenn > 108°C, for example Ttrenn = 110°C.

[0075] The process preferably comprises the step of separating the conducting salt from the scrubbing liquid. Regeneration of the scrubbing solvent produces a separation residue. If the regeneration involves vacuum distillation, a distillation bottoms product is formed. Preferably, the conducting salt is separated from the separation residue, in particular the distillation bottoms. For example, the conducting salt is separated by crystallization.

[0076] It is advantageous if the separated conducting salt is used to produce new alkali metal batteries.

[0077] Preferably, the washing solvent consists of at least 50 percent by weight of a compound or compounds that are part of the electrolyte. It is advantageous if the process comprises the step of withdrawing washing solvent from a washing solvent circuit in which the washing solvent is conveyed.

[0078] It is advantageous if the extracted washing solvent is used to produce new alkali metal batteries.

[0079] According to a preferred embodiment, the method comprises the step of grinding the low-conductive salt comminution material. This can be done, for example, using a turbo mill, an impact mill, or a ball mill. The low-conductive salt comminution material preferably still contains foil components, in particular parts of the carrier foil and / or metal foil components. The low-conductive salt comminution material preferably contains at least one-third of the proportion by weight of metal foil components in the comminution material immediately after comminution; in particular, all metal foil components are still present.

[0080] After grinding, the black mass is preferably sieved. The black mass represents the fraction with the smallest grain size. Components, particularly copper and / or aluminum foil particles, are preferably separated from the remaining fraction. This is done, for example, using a fluidized-bed separator or a classifier. The binder is preferably extracted from the resulting black mass using a binder solvent, as described below.

[0081] According to a preferred embodiment, the method comprises the step of removing, in particular dissolving, the binder from the low-conducting salt comminution material, in particular the low-conducting salt black mass, using a binder solvent, so that low-binder comminution material, in particular low-binder black mass, is obtained. The binder solvent is in particular not the washing solvent. In order to be able to reuse the active material, in particular the graphite, for the production of alkali metal batteries, it must have a high purity. It has been found that this purity is easier to achieve if the binder is dissolved out.

[0082] While complete removal of the binder is theoretically desirable, it is not complete in practice. Preferably, at least 50 weight percent, in particular at least 60 weight percent, in particular at least 70 weight percent, in particular at least 80 weight percent, in particular at least 90 weight percent, of the binder is removed. Preferably, at most 99 weight percent of the binder is removed. Alternatively, the binder solvent is a component of the conducting salt solvent. Although the conducting salt solvent obviously does not dissolve the binder at operating temperature, it has surprisingly been found that the conducting salt solvent can dissolve the binder, particularly at high temperatures.

[0083] Alternatively or additionally, the method preferably comprises the step of dissolving a solid electrolyte from the low-conducting salt comminution material, in particular the low-conducting salt black mass, with a solvent, so that low-solid electrolyte comminution material, in particular low-solid electrolyte black mass, is obtained.

[0084] The binder solvent is preferably 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.

[0085] Preferably, the binder is dissolved out using at least one diluent. The diluent is preferably γ-butyrolactone (GBL), dimethyl sulfoxide (DMSO), 3-heptanone, or 3-octanone. The diluent is used together with the binder solvent to dissolve out the binder. For example, the binder solvent is mixed with the diluent. However, a diluent is not required.

[0086] The dissolution of the binder and / or the solid-state electrolyte preferably takes place at at least 70°C, in particular at least 90°C, in particular at least 110°C, in particular at least 130°C, in particular at least 150°C, in particular at least 175°C, in particular at least 200°C, in particular at least 240°C, in particular at least 260°C, in particular at least 280°C, in particular at least 290°C.

[0087] This temperature is preferably lower than the boiling point of the binder solvent at the pressure used. It is advantageous if the binder is dissolved out at a temperature that is at most 30 Kelvin, in particular at most 20 Kelvin, and preferably at most 10 Kelvin, below the boiling point of the binder solvent at the respective process pressure.

[0088] Preferably, the binder is extracted under overpressure, for example at least 100 hPa overpressure, in particular at least 200 hPa overpressure, at least 500 hPa overpressure, at least 1000 hPa overpressure, at least 2000 hPa overpressure, at least 3000 hPa overpressure. Preferably, the overpressure is at most 10 MPa. This overpressure is the process pressure.

[0089] Before the binder is dissolved out, the low-conducting salt crushing material, in particular the low-conducting salt black mass, is preferably not pyrometallurgically oxidized and / or not heated to a temperature of more than 300°C, in particular not to more than 250°C.

[0090] Before dissolving the binder, the low-conducting salt crushing material, especially the low-conducting salt black mass, is preferably not heated in a hydrogen-containing atmosphere.

[0091] According to a preferred embodiment, the process comprises the step of post-washing the low-binder comminution material, in particular the low-binder black mass, with a post-wash solvent so that the binder solvent is washed out. The post-wash solvent is preferably an organic solvent. The boiling point of the post-wash solvent is preferably below the boiling point of the binder solvent, preferably below 100°C at atmospheric pressure, in particular below 90°C, in particular below 80°C, preferably below 70°C. For example, the post-wash solvent is acetone.

[0092] The process preferably comprises the step of regenerating the post-wash solvent. This can be done, for example, by distillation, in particular vacuum distillation. The regeneration separates the post-wash solvent from the binder solvent, which is preferably reused for post-washing. The wash solvent preferably contains at most 5% by weight, preferably at most 3% by weight, particularly preferably at most 1% by weight, in particular essentially no alkaline earth metal hydroxide. The feature that essentially no alkaline earth metal hydroxide is present is understood in particular to mean that any amount of alkaline earth metal hydroxide present can be neglected.

[0093] Preferably, the washing solvent is selected such that, during washing, at most 20 mol%, at most 10 mol%, more preferably at most 5 mol%, and most preferably at most 1 mol% of the lithium reacts to form lithium hydroxide. Preferably, the washing solvent is selected such that no lithium hydroxide is formed during washing.

[0094] Before the binder is removed, the low-conducting salt crushing material, in particular the low-conducting salt black mass, is not digested, i.e. it has not been treated with a mineral acid.

[0095] According to a preferred embodiment, the method comprises the step of separating, in particular classifying, the low-binder comminution material, in particular the low-binder black mass, so that a graphite fraction and a transition metal fraction in which at least one transition metal is enriched compared to the graphite fraction are obtained.

[0096] However, it is not necessary that the separation is carried out on low-binder crushing material.

[0097] According to one embodiment, the method first comprises step (i) according to claim 1, then pre-drying, then separation of plastic particles, in particular of particles from comminuted casing and / or comminuted carrier film, so that black mass is obtained, then steps (ii), (iii), (iv) according to claim 1, then optionally drying the black mass and then sifting the, optionally dried, black mass. In this case, the drying is preferably carried out such that at least 70 percent by weight, in particular at least 80 percent by weight, particularly preferably at least 90 percent by weight, in particular at least 95 percent by weight, of the washing solvent contained in the black mass is removed.

[0098] Alternatively or additionally, the pre-drying is preferably carried out such that at least 50 percent by weight, in particular at least 60 percent by weight, preferably at least 70 percent by weight, particularly preferably at least 80 percent by weight, particularly preferably at least 90 percent by weight, of the electrolyte and / or the electrolyte solvent are removed.

[0099] A transition metal refers to elements that have an incomplete d-subshell or form ions with an incomplete d-subshell. In particular, cobalt and / or nickel are enriched in the transition metal fraction compared to the graphite fraction, preferably by at least an enrichment factor of 3 (meaning that the concentration of the corresponding transition metal in the transition metal fraction is at least three times greater than the concentration of the corresponding transition metal in the graphite fraction), in particular an enrichment factor of 4, in particular an enrichment factor of 5, preferably an enrichment factor of 6.

[0100] It has been found that a high enrichment factor is particularly easy to achieve when as much binder as possible is removed. The exact reason for this is not entirely known. It is assumed that the binder bonds individual graphite particles to each other and to particles containing transition metal or a transition metal salt, thus making separation possible.

[0101] Separation may also involve or involve flotation, particularly froth flotation. However, it has been shown that a higher enrichment factor can be achieved through screening.

[0102] Preferably, the screening is a fine screening process. It is advantageous if the screening is carried out using a fine screener with a screening wheel. The screening wheel can also be referred to as a classifying wheel. The screening 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, and particularly preferably at most 10 mm.

[0103] 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.

[0104] 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.

[0105] 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.

[0106] According to a preferred embodiment, the method comprises the step: after washing the comminution material, in particular the black mass, with the washing solvent, drying the comminution material with a low conducting salt content, in particular the black mass with a low conducting salt content. This drying preferably takes place at a maximum of 80°C, in particular a maximum of 70°C, in particular a maximum of 60°C, in particular a maximum of 50°C, preferably a maximum of 45°C. In this way, the formation of hydrogen fluoride is substantially prevented. The feature that the formation of hydrogen fluoride is substantially prevented is understood in particular to mean that during drying in the gas atmosphere, a hydrogen fluoride concentration of at most 1 mg / m 3 amounts.

[0107] Alternatively, drying is carried out at a temperature above the boiling point of the washing solvent. This is advantageous if washing with the washing solvent is carried out for such a long time that the content of conductive salt is so low that at least essentially no hydrogen fluoride is formed during subsequent drying. For example, drying is carried out at a temperature of at least 80°C, in particular at least 100°C, in particular at least 120°C.

[0108] The process preferably comprises the step of: after drying, washing the low-conducting salt comminution material, in particular the low-conducting salt black mass, with a second solvent whose boiling point is lower than the boiling point of the washing solvent. If the washing solvent contains two or more components, the second solvent preferably has a lower boiling point than all components of the washing solvent. Preferably, the thus-treated comminution material, in particular the black mass, is then dried again.

[0109] After drying, especially pre-drying, film components, in particular plastic and / or metal foil components and / or particles from shredded casing, are preferably separated. This occurs in particular before the binder is removed. The separation is preferably carried out such that the film weight fraction of film components after separation amounts to at most one-fifth of the film weight fraction before separation. As a result, the binder solvent hardly comes into contact with the plastic or metal foils during the binder removal process.

[0110] Preferably, the low-binder comminution material, in particular the low-binder black mass, is dried before dissolving the binder. Drying is preferably carried out at a pressure of no more than 300 hPa, in particular no more than 10 hPa. This reduces contamination of the binder solvent.

[0111] It is advantageous if the graphite from the graphite fraction is used to produce new alkali metal batteries.

[0112] It is advantageous if the process includes the following step: before washing the shredded material, separating film portions from the shredded material. The resulting shredded material, which can also be referred to as low-film shredded material, can be easily washed with the washing solvent. The films can be carrier films, in particular plastic films and / or metal foils. For example, they are parts of the separator film and / or aluminum foil and / or copper foil.

[0113] According to a preferred embodiment, the method includes the following step: after comminution, preferably after separating film parts or before separating film parts and / or particles from the comminuted casing, and before washing the comminution material, pre-drying the comminution material. The pre-drying is preferably carried out such that at least 50 percent by weight, in particular at least 60 percent by weight, preferably at least 70 percent by weight, particularly preferably at least 80 percent by weight, particularly preferably at least 90 percent by weight, of the electrolyte and / or the electrolyte solvent is removed. The pre-drying can also be generally referred to as drying.

[0114] In particular, the method comprises the steps of (a) drying the comminution material to produce dried comminution material, (b) separating plastic particles, in particular particles of comminution of casing and / or comminution of carrier film and / or comminution of separator films, from the dried comminution material to obtain black mass, and (c) washing the black mass with the washing solvent. The plastic particles are preferably not washed with the washing solvent. This prevents contamination of the washing solvent with components from the plastic. Furthermore, swelling of the plastic particles is prevented.

[0115] Preferably, the pre-drying is carried out at a pressure of at most 300 hPa and / or a temperature of at most 70°C, in particular at most 60°C, in particular at most 50°C. Preferably, the pre-drying is carried out at such a low temperature that at most 5 mol percent, in particular at most 1 mol%, of the fluorine in the comminution material reacts to form hydrogen fluoride.

[0116] According to a preferred embodiment, the method comprises the step: prior to comminution, short-circuiting the batteries until at least 75% of the galvanic elements have a regeneration cell voltage of at most 0.4 volts, in particular at most 0.3 V, preferably at most 0.2 volts, in particular at most 0.15 volts, particularly preferably at most 0.1 volts, in particular at most 0.05 V.

[0117] Short-circuiting the batteries allows the conductive salt to be recovered with particularly high purity. Why this short-circuiting increases the purity of the recovered conductive salt is not fully understood. 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.

[0118] 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 battery until its capacity is almost completely depleted, particularly below the cut-off voltage. The cut-off voltage can be, for example, 0.1 volts. The energy content of the batteries 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 low. Therefore, state-of-the-art processes only perform deep discharge.

[0119] However, it has been found that the energy content is sufficiently high even after deep discharge 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 shown that even small contamination of the conducting salt with decomposition products can impair the suitability of the conducting salt and / or the electrolyte for the production of new batteries.

[0120] The regeneration cell voltage is the cell voltage present at the respective galvanic element after a specified regeneration period, during which the battery poles are electrically unconnected. The characteristic that the battery poles are electrically unconnected means that the poles are insulated from each other, i.e., in particular, that there is a resistance of at least 1 megaohm between the two poles. In other words, no electrical energy is drawn from the galvanic element during the regeneration period. In particular, the poles of the battery's galvanic elements are electrically unconnected during the regeneration period.

[0121] During the regeneration period, the cell voltage increases. Even discharging a battery to a cell end voltage of, for example, below 0.2 V, such as 0 V, results in a regeneration cell voltage higher than the cell end voltage.

[0122] 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 regeneration cell voltage was 0.8 V. After a 5-hour short-circuit, the regeneration cell voltage was 0.6 V. After a 24-hour short-circuit, the regeneration cell voltage was 0.2 V.

[0123] Short-circuiting the batteries for such a long time that the regeneration cell voltage is at most 0.2 V, especially at most 0.15 V, especially 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 the batteries have been short-circuited in a regeneration-safe manner.

[0124] Whether a regeneration-safe short-circuit has occurred can be determined by storing the battery in question for the regeneration period without external electrical load, and in particular without a short circuit, at 1013 hPa and 23°C, and then measuring the cell voltage. In other words, short-circuiting 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.

[0125] The regeneration time is 12 hours. Please note that this does not specify how long the batteries are short-circuited. Rather, the regeneration time is the time the batteries remain in a non-contact, or in particular non-short-circuited, state after discharging, especially after short-circuiting. In particular, short-circuiting the batteries for 12 hours can result in the regeneration cell voltage still being above 0.2 volts.

[0126] Preferably, the batteries 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 is possible—as provided in a preferred embodiment—to ensure that at least 90 percent by weight, in particular at least 95 percent by weight, of the conducting salt of the batteries does not decompose during comminution.

[0127] Preferably, the steps prior to washing the black mass are carried out in such a way that the conducting salt of the alkali metal batteries decomposes to a maximum of 10% by weight, in particular to a maximum of 5% by weight, in particular to a maximum of 3% by weight, in particular to a maximum of 1% by weight, in particular to a maximum of 0.5% by weight, in particular to a maximum of 0.1% by weight.

[0128] 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.

[0129] During short-circuiting, the electrical resistance between the positive pole of the battery and a negative pole of the battery is preferably at most 10 ohms, in particular at most 1 ohm, preferably at most 0.3 ohms, particularly preferably at most 0.1 ohms. It is possible, but not necessary, for the battery to be transported after the regeneration-safe short-circuiting, in particular over a distance of at least 1 km, in particular at least 5 km. The regeneration-safe short-circuiting particularly lows the risk of fire and thus of environmental hazards posed by the battery. Preferably, the battery is not transported over a distance of more than 1 km after the regeneration-safe short-circuiting, as such transport can also pose a safety risk.

[0130] According to a preferred embodiment, the comminution material is essentially not brought into contact with water prior to washing. The feature that the comminution material is essentially not brought into contact with water is understood in particular to mean that contact with water, which leads to a reaction of at least 5 mol%, in particular more than 1 mol%, particularly preferably more than 0.1 mol%, of the conductive salt, does not occur. In particular, comminution is carried out without introducing water, in particular not by waterjet cutting.

[0131] Preferably, the comminution material contains at least substantially no organic cations. This is understood, in particular, to mean that the content of substances containing organic cations is at most 0.1 percent by weight. Particularly preferably, the comminution material contains no organic cations and / or no double-layer capacitors.

[0132] Preferably, the active material and / or the electrolyte are substantially not brought into contact with water before and during comminution. This specifically means that there is no contact with water that would lead to a reaction of more than 5 mol%, in particular more than 1 mol%, in particular more than 0.1 mol% of the conductive salt or the electrolyte.

[0133] During washing, the active material and / or the electrolyte are preferably not brought into contact with water. This particularly means that there is no contact with water that would lead to a reaction of more than 5 mol%, in particular more than 1 mol%, in particular more than 0.1 mol% of the conductive salt or the electrolyte. Preferably, the comminution is carried out at a temperature so low that at most 2.5 mol%, in particular at most 1 mol%, and particularly preferably at most 0.5 mol%, of the fluorine, based on the comminution material, decomposes.

[0134] Preferably, the low-binder crushing material, especially the low-binder black mass, is digested with concentrated sulfuric acid and then leached. Because it contains almost no binder, sulfuric acid consumption is low. This provides a simple method for obtaining graphite low in metal ions. This can, if necessary, be reused for the production of alkali metal batteries.

[0135] The battery processing plant according to the invention preferably comprises a separation device designed and arranged to separate black mass from the residual fraction. For example, the separation device is a sifter or a sieve.

[0136] In summary, the invention also provides the following process for recycling alkali metal batteries, in particular Li batteries or Na batteries, which

[0137] (a) an active material, in particular graphite,

[0138] (b) a carrier film on which the active material is arranged,

[0139] (c) Binder with which the active material is bonded to the carrier film,

[0140] (d) a liquid electrolyte,

[0141] (e) Conductive salt and

[0142] (f) a housing surrounding the active material, carrier film and binder, characterized by the steps

[0143] (i) optionally discharging and short-circuiting so that the regeneration voltage is below 0.2 V, in particular 0.1 V,

[0144] (ii) crushing the alkali metal batteries to produce crushing material containing black mass, active material and binder, and

[0145] (iii) optionally drying the shredded material, in particular at below 70°C and / or at a maximum pressure of 300 hPa,

[0146] (iv) optionally separating the black mass, in particular by sifting, (v) washing the comminution material, in particular the black mass, with a washing solvent so that the conductive salt is washed out and the binder is not washed out, so that comminution material with a low conductive salt content, in particular black mass with a low conductive salt content, is obtained, wherein the washing solvent is a component of the electrolyte, wherein washing is preferably carried out until at most 10% by weight, in particular at most 5% by weight, particularly preferably at most 1%, in particular at most 1% by weight, in particular at most 0.1%, in particular at most 0.1% by weight, in particular at most 1%, in particular at most 0.1% by weight, in particular at most 0.1% of the conductive salt remains, the washing solvent is recovered, the conductive salt and / or a substance having the same anion as the conductive salt is separated from the residue resulting from the recovery of the washing solvent,at least one solvent which is an electrolyte component and not the washing solvent is separated from the residue and is reused in particular for recycling in new batteries,

[0147] (vi) optionally drying the low-conducting salt crushing material, in particular the low-conducting salt black mass (which can be carried out at a temperature above the boiling point of the washing solvent, preferably below the binder decomposition temperature), optionally washing with a second washing solvent with a lower boiling point than the washing solvent,

[0148] (vii) optionally dissolving the binder from the low-conducting salt black mass with a binder solvent (which is not the washing solvent) so that low-binder comminution material is obtained,

[0149] (viii) optionally drying the low-binder crushing material and

[0150] (ix) optionally separating, in particular classifying, the low-binder comminution material so as to obtain a graphite fraction and a transition metal fraction in which at least one transition metal is enriched compared to the graphite fraction, (x) optionally producing new batteries, in particular alkali metal batteries, from graphite of the graphite fraction and / or the washing solvent and / or the deposited conducting salt.

[0151] The process preferably comprises the step of washing out the binder solvent. This is done, for example, with an organic solvent, which can be called a binder washout solvent. The binder washout solvent preferably has a boiling point lower than that of the binder solvent. The boiling point at atmospheric pressure is preferably below 100°C, in particular below 90°C, in particular below 80°C, in particular below 70°C, in particular below 60°C.

[0152] In a battery processing plant according to the invention, the regenerator is preferably a vacuum distiller which is designed to automatically distill off a low-boiling fraction of the washing liquid, wherein the low-boiling fraction forms the washing liquid.

[0153] The battery processing plant preferably has a binder removal plant designed to automatically remove binder from the low-conductive salt comminution material, in particular the low-conductive salt black mass, using a binder solvent. The binder removal plant is preferably arranged downstream of the washing device in the material flow direction. It is possible, but not necessary, for a dryer and / or a separating device to be arranged upstream of the binder removal plant in the material flow direction. The binder removal plant is preferably designed to heat the low-conductive salt comminution material, in particular the low-conductive salt black mass, to a temperature above a binder decomposition temperature TBZ. The binder decomposition temperature TBZ is the temperature at which half of the binder has decomposed after 30 minutes.In this way, residues of the binder are further reduced, so that the subsequent separation leads to a higher enrichment factor.

[0154] Preferably, the battery processing plant has a binder removal plant which is designed to automatically remove binder from the comminution material, in particular the black mass, which is in particular low in conductive salt, by means of a binder solvent.

[0155] If a binder removal system is present, the battery processing system preferably has a post-washer which is designed to wash out the binder solvent from the low-binder comminution material, in particular the low-binder black mass, with a post-wash solvent.

[0156] The invention is explained in more detail below with reference to the accompanying drawings.

[0157] Figure 1 is a flow diagram of a battery processing plant according to the invention,

[0158] Figure 2 shows a flow diagram of a battery processing plant according to the invention according to a second embodiment,

[0159] Figure 3 is a flow diagram of a battery processing system according to the invention according to a third embodiment and

[0160] Figure 4 is a flow diagram of a battery processing system according to the invention according to a fourth embodiment.

[0161] Figure 1 shows a battery processing system 10 according to the invention for recycling alkali metal batteries 12, in this case lithium in the form of lithium-ion accumulators. The alkali metal batteries 12 are first discharged preferably, but not necessarily, using a discharge device 14. The electrical energy can be fed into a power grid, for example, the public power grid, but this is not necessary.

[0162] After discharging, the alkali metal batteries 12 are preferably, but not necessarily, short-circuited. In other words, a positive pole 16 and a negative pole 18 are connected to each other. The electrical resistance between the positive pole 16 and a negative pole 18 is preferably less than one-fifth, in particular one-tenth, of the internal resistance of the corresponding alkali metal battery. The short-circuiting is carried out over a short-circuit time TK. The short-circuit time TK is selected to be long enough to ensure a regeneration cell voltage llreg is below llreg = 0.15 V. For example, Ts = 12 hours.

[0163] The alkali metal batteries 12 are crushed in a crushing system 20 to produce crushed material 22. The crushing system 20 is preferably designed such that no more than 5 percent by mass of the crushed material 22 has a spherical diameter of more than 4 cm. The spherical diameter is the diameter of an imaginary sphere of minimal diameter that completely surrounds the respective object.

[0164] The shredded material 22 is conveyed to an optional separating device 26 via a preferably gas-tight line 24.1. It is possible, but not necessary, for a lock 28.1 to be arranged between the shredding system 20 and the separating device in the material flow direction M. The separating device 26 separates the black mass 30 from a residual fraction 32. The residual fraction 32 comprises, for example, plastic components of a possibly present housing or separator.

[0165] The separation device 26 is shown as a sifter, but it can - very generally and not only related to the embodiment according to D1 - also be a screening system, a combination of a screening system and a sifter or a separation device based on another separation principle.

[0166] The black mass 30 (or the comminution material 22 if no separation device 26 is present) passes through a preferably gas-tight line 24.2 into a washing device 34, where it is brought into contact with a washing solvent 36. The washing solvent 36 dissolves conductive salt 38 from the black mass 30, producing a washing liquid 40.

[0167] The washing liquid 40 enters a regenerator 42, which—as in the present case—can be designed as a vacuum distiller. Instead of "vacuum distiller," the term "vacuum distillation device" can also be used. The regenerator 42 has a temperature control device 43 and separates the washing liquid 40 into at least a low-boiling fraction, which forms the washing solvent 36, and a high-boiling fraction 44.

[0168] The highest temperature prevailing in the vacuum distiller 42 at a point in contact with the conducting salt is referred to as the regeneration temperature Tr. Preferably, Tr < 60°C, for example, Tr = 50°C. The temperature control device 43 sets the regeneration temperature Tr.

[0169] A distillation pressure p42 prevails in the vacuum distillator 42. The distillation pressure p42 is preferably selected so that both ethyl methyl carbonate (EMC, ethyl methyl carbonate) and dimethyl carbonate (DMC, dimethyl carbonate) evaporate.

[0170] Preferably, the distillation pressure p42 is selected so that no substances evaporate whose boiling point at atmospheric pressure (1013 hPa) is above a separation boiling point Tsepar. Preferably, Tsepar > 108°C, for example, Tsepar = 110°C.

[0171] In the present embodiment, the gaseous EMC and DMC are condensed by means of a condenser 46 and returned to the scrubbing device 34 as scrubbing solvent 36. In the gas flow direction G, upstream of the condenser 46, a temperature in the range of the separation boiling point Tsepar prevails. It is advantageous to monitor this temperature using a thermometer 47.

[0172] A portion of the washing solvent 36 can be withdrawn, for example, via a drain line 48.1, and fed to an electrolyte container 50. The washing solvent 36 can be used, optionally after further processing, to produce new alkali metal batteries.

[0173] The high-boiling fraction 44, which contains the conducting salt, remains in the vacuum distiller 42. The components of the high-boiling fraction 44 have a boiling point above the separation boiling point Tsepar. The high-boiling fraction 44 is withdrawn, for example, via a second withdrawal line 48.2, and can be fed to a transport container 52. The distillation pressure p42 is preferably less than 286 hPa, in particular less than 233 hPa, particularly preferably less than 188 hPa, in particular less than 150 hPa.

[0174] In the present embodiment, the low-boiling fraction contains substances whose boiling point at atmospheric pressure is between 85°C, in particular 88°C and 109°C. If the alkali metal batteries are lithium-ion accumulators, the low-boiling fraction contains, in particular, dimethyl carbonate and ethyl methyl carbonate.

[0175] In the present embodiment, the high boiler fraction 44 contains substances whose boiling point at atmospheric pressure is above 110°C.

[0176] In the present embodiment, the washing device 34 is operated in batch mode. Washing is carried out until the conducting salt concentration in the washing liquid 40 falls below a predetermined limit concentration C limit. The black mass 30 is then referred to as the low-conducting-salt black mass 30'. The limit concentration C limit is preferably selected such that at least 95 percent by weight of the conducting salt has been washed out of the black mass 30.

[0177] The low-conducting salt black mass 30' passes through an optional lock 28.3 into an optional dryer 54. The dryer 54 can be designed as a vacuum dryer, as in the present case, but this is not necessary. The dryer pressure ps4 in the dryer 54 is then, for example, ps4 < 300 hPa. A dryer temperature T54 in the dryer 54 is preferably below T54 = 60°C. The washing solvent 36 present in the low-conducting salt black mass 30' is thus evaporated and condensed in a condenser 56.

[0178] The dryer 54 preferably has a mixer 57 to improve the contact between the washing solvent 36 and the black mass 30 and thus the discharge of conductive salt and electrolyte components that do not form the washing solvent 36. A binder removal system 58 is arranged downstream of the washing device 34 in the material flow direction M, and in the present case downstream of the dryer 54. The black mass 30', which is low in conductive salt, passes through a preferably gas-tight line 24.4 and optionally a lock 28.4 into the binder removal system 58, where it is mixed with a binder solvent 60, for example, dimethyl sulfoxide.

[0179] If the binder solvent 60 contains supercritical carbon dioxide, as provided in a preferred embodiment, the temperature and pressure in the binder removal system are selected such that the carbon dioxide is supercritical.

[0180] Preferably, a binder removal temperature Tss in the binder removal system 58 is as high as possible, in particular close to the boiling point Ts.eo of the binder solvent 60. Preferably, the binder removal temperature is at least Ts.eo = 170°C. Preferably, Ts.eo = < 400°C, in particular

[0181] Ts, 60 = < 375°C. To achieve the highest possible binder removal temperature, it is advantageous if the process pressure pss in the binder removal system 58 is greater than the ambient pressure. Preferably, pss > 1200 hPa, especially pss > 2000 hPa. In particular, pss is 12 MPa.

[0182] The binder removal system 58 preferably has a stirrer 60 for introducing mechanical energy into the low-conducting salt black mass 30'. It is advantageous if the pH value in the binder removal system 58 is at most 9.

[0183] The binder removal system 58 is operated, for example, in batch mode. The binder solvent 60 is exchanged frequently until at least 40%, preferably at least 50%, of the binder has been removed from the low-conducting salt black mass 30'. The low-binder black mass 30' thus produced is then dried, for example, via a line 24.5, in a dryer 54.2. It is possible, but not necessary, for a temperature T54.2 in the second dryer to be above a binder decomposition temperature TBZ. Any resulting off-gas 62 is purified by an off-gas purification system 64, in particular from hydrogen fluoride, and then released into the environment. The low-binder black mass 30'' enters a separation device 66, which in this case is designed as a fine classifier. The fine classifier 66 has a classifying wheel 68, which is brought by means of a motor 70 to a classifying wheel rotation frequency fes of, for example, fes = 150 1 / s.

[0184] A coarse fraction 74 leaves the fine classifier 66 through a coarse fraction outlet 72, and a fine fraction 78 leaves the fine classifier 66 through a fine fraction outlet 76. The coarse fraction 74 contains significantly more graphite than the fine fraction 78 and can therefore also be referred to as the graphite fraction. The fine fraction 78, on the other hand, contains significantly more transition metal than the coarse fraction 74 and can therefore also be referred to as the transition metal fraction.

[0185] Figure 2 shows a second embodiment of a battery reprocessing plant according to the invention, in which the vacuum distillator 42 is designed as a rectifier, i.e. as a device for fractional distillation.

[0186] In this case, it is advantageous if the fraction with the lowest boiling point is used as washing solvent 36 or has the highest proportion in weight percent of washing solvent 36.

[0187] Figure 3 shows a third embodiment of a battery reprocessing system 10 according to the invention for recycling alkali metal batteries 12, in particular Li batteries or Na batteries, comprising (a) a comminution system 20 for comminution of the batteries, so that comminution material 22 is obtained, which contains black mass 30, wherein the black mass contains in particular the active material and the binder, (b) a washing device 34, which is arranged downstream of the comminution system 20 in the material flow direction and is designed to wash at least a fraction of the comminution material 22, in particular black mass 30, with a washing solvent 36, so that comminution material 22 with a low content of conductive salt and a washing liquid 40 are obtained, and (c) a regenerator 42, which (i) is designed to automatically regenerate washing solvent 36 from the washing liquid 40, (ii) a supply line,which is connected to the washing device 34 for conducting washing liquid 40 from the washing device 34 to the regenerator 42, and (iii) a return line connected to the washing device 34 for conducting washing solvent 36 from the regenerator 42 to the washing device 34.

[0188] The battery processing plant 10 has a pre-dryer 80, which is arranged downstream of the shredding plant 20 and upstream of a separating device 26 in the material flow direction M. In the pre-dryer, a pressure ps4' of a maximum of 300 hPa prevails, for example, p54 = 100 hPa. This negative pressure is generated by a vacuum pump 82.

[0189] A condenser 56' for condensing conductive salt solvent 86 can optionally be arranged upstream (or alternatively downstream) of the vacuum pump 82 in the gas flow direction G. The conductive salt solvent 84 can be used, for example, as washing solvent 36 or reused directly.

[0190] A particulate filter 88 can optionally be arranged upstream of the condenser 84 in the gas flow direction G. An activated carbon filter 90 can optionally be arranged downstream of the vacuum pump 82 in the gas flow direction G. The gases thus purified can then be further purified or released directly into the environment.

[0191] The pre-dryer 80 can be connected to the separating device 26 by means of a lock 28.5 and a preferably particle-tight line 24.6.

[0192] In the separation device 26, the black mass 30 is separated from the residual fraction 32. The residual fraction includes, in particular, heavy material, i.e., particles resulting from the shredding of the housing, as well as shredded carrier foil and / or shredded separator foils. The washing device 34, which washes out the conductive salt and washing solvent 36, is arranged downstream of the separation device 26 in the direction of material flow.

[0193] The battery processing plant 10 can optionally comprise the dryer 54, which is arranged behind the washing device 34 in the material flow direction.

[0194] The battery processing plant 10 can optionally comprise the binder removal plant 58, which is arranged downstream of the washing device 34 in the material flow direction, in particular, if present, downstream of the dryer 54. If the battery processing plant 10 comprises a binder removal plant 58, it can optionally comprise a post-scrubber 92, by means of which the binder solvent 60 is washed out of the low-binder black mass 30" with a binder washout solvent 94, thus obtaining wash solution 96. Preferably, the battery processing plant has a wash solution regenerator 98 for separating binder washout solvent 94 from the wash solution 96.

[0195] Optionally, the battery processing plant 10 has a classifier, in particular a fine classifier 66, for producing a graphic fraction and a transition metal fraction from the optionally low-binder black mass 30'".

[0196] Optionally, the battery processing system 10 has the discharge device 14.

[0197] The battery processing system 10 may include all of the components shown in Figure 3, but this is not necessary.

[0198] Figure 4 shows a further embodiment of a battery processing plant 10 according to the invention for recycling alkali metal batteries 12, in particular Li batteries or Na batteries, comprising (a) a comminution plant 20 for comminution of the batteries, so that comminution material 22 is obtained, the black mass 30 containing the active material and the binder, (b) a washing device 34, which is arranged downstream of the comminution plant 20 in the material flow direction and is designed to wash at least a fraction of the comminution material 22, in particular black mass 30, with a washing solvent 36, so that comminution material 22 with a low conductive salt content and a washing liquid 40 are obtained, and (c) a regenerator 42, which (i) is designed to automatically regenerate washing solvent 36 from the washing liquid 40, (ii) a feed line,which is connected to the washing device 34 for conducting washing liquid 40 from the washing device 34 to the regenerator 42, and (iii) a return line connected to the washing device 34 for conducting washing solvent 36 from the regenerator 42 to the washing device 34. Furthermore, the battery reconditioning system 10 has a dryer 54 arranged downstream of the washing device 34 in the material flow direction M. The dryer 54 can be a vacuum dryer in which a process pressure ps4 of, for example, at most ps4 = 300 hPa and / or a dryer temperature T54 of, for example, at most T54 = 70 °C prevails. The preferred dryer temperatures specified above also apply here.

[0199] Alternatively, the dryer 54 can operate at atmospheric pressure or overpressure and / or a dryer temperature T54 of above 70°C, in particular above 80°C, for example above 90°C. For example, the dryer temperature is above the boiling point Ts, 36 of the washing solvent 36.

[0200] The separating device 26, in which the black mass 30 is separated from the residual fraction 32, is arranged downstream of the dryer 54 in the material flow direction. The residual fraction includes, in particular, heavy material, i.e., particles resulting from the shredding of the housing, as well as shredded carrier film and / or shredded separator films.

[0201] Optionally, the battery processing plant 10 has a binder removal system 58, in which binder solvent 60 is used to dissolve binder in the black mass 30. Optionally, the battery processing plant 10 has another dryer 54.2 for drying the low-binder black mass 30.

[0202] If the battery processing plant 10 includes a binder removal plant 58, it may optionally include a post-scrubber 92, by means of which the binder solvent 60 is washed out of the low-binder black mass 30" with a binder washout solvent 94, thereby obtaining wash solution 96. Preferably, the battery processing plant includes a wash solution regenerator 98 for separating binder washout solvent 94 from the wash solution 96.

[0203] Optionally, the battery processing plant 10 has a classifier, in particular a fine classifier 66, for producing a graphic fraction and a transition metal fraction from the optionally low-binder black mass 30'". The battery processing plant 10 can have all the components shown in Figure 4, but this is not necessary.

[0204] For example, the battery processing plant 10 does not have a dryer and / or separation device upstream of the binder removal plant 58 in the material flow direction.

[0205] List of reference symbols

[0206] 10 battery processing plants 50 electrolyte containers

[0207] 12 alkaline metal battery 52 transport container

[0208] 14 Unloading device 54, 54' dryer

[0209] 16 Positive pole 56 Capacitor

[0210] 18 Negative pole 57 Mixer

[0211] 58 Binder removal system

[0212] 20 crushing plant

[0213] 22 comminution material 60 binder solvent

[0214] 24 Line 62 Exhaust

[0215] 26 Separator 64 Exhaust gas purification system

[0216] 28 Lock 66 Fine Sifter

[0217] 68 sight wheel

[0218] 30 black mass

[0219] 32 residual fraction 70 engine

[0220] 34 Washing device 72 Coarse fraction outlet

[0221] 36 Washing solvent 74 Coarse fraction

[0222] 38 Conductive salt 76 Fine fraction outlet

[0223] 78 fine fraction

[0224] 40 Washing liquid

[0225] 42 Regenerator 82 Vacuum pump

[0226] 43 Temperature control device 84 Condenser

[0227] 44 High boiler fraction 86 Conductive salt solvent

[0228] 46 Condenser 88 Particle filter

[0229] 47 Thermometer 90 Activated carbon filter

[0230] 48 Exhaust pipe

[0231] 92 Post-scrubber 94 Binder wash-out solvent

[0232] 96 Washing solution

[0233] Climit Limit concentration fes Classifying wheel rotation frequency

[0234] G Gas flow direction

[0235] M Material flow direction

[0236] P42 Distillation pressure

[0237] P54 Process pressure

[0238] P58 Process pressure in the binder removal system

[0239] Ts, 36 Boiling temperature of the washing solvent

[0240] T54 dryer temperature

[0241] TK short-circuit time

[0242] T r Regeneration temperature

[0243] Ureg regeneration cell voltage

Claims

Process for recycling alkali metal batteries (12), in particular Li-batteries or Na-batteries, which (a) an active material, (b) a carrier film on which the active material is arranged, (c) Binder with which the active material is bonded to the carrier film, (d) a liquid electrolyte, (e) Conductive salt (38) and (f) a housing surrounding the active material, carrier film and binder, comprising the step (i) crushing the alkali metal batteries (12) to produce crushed material containing black mass (30) containing the active material and the binder, characterized by the steps (ii) washing the comminution material with a washing solvent (36) so that conductive salt (38) is washed out and the binder is not washed out, so that comminution material with a low content of conductive salt and a washing liquid (40) are obtained, (iii) regenerating the washing solvent (36) from the washing liquid (40), and in particular by distillation, and (iv) washing the crushed material with at least a portion of the regenerated washing solvent (36), (v) wherein the washing solvent (36) is a component of the electrolyte. Method according to claim 1, characterized by the step of separating the black mass (30) from a residual fraction (32) after comminuting the alkali metal batteries (12), in particular by sifting or sieving, wherein the black mass (30) is washed with the washing solvent (36). Method according to one of the preceding claims, characterized in that a washing solvent main component concentration of a main component of the washing solvent (36), measured in percent by weight, deviates by a factor of at most 10 from a conducting salt solvent main component concentration of a main component of the conducting salt solvent. Method according to one of the preceding claims, characterized in that (a) the washing solvent (36) is not substantially contacted with water and (b) the regeneration of the washing solvent (36) comprises distilling and separating the conducting salt (38) from the washing liquid (40). Method according to claim 4, characterized in that the regeneration of the washing solvent (36) comprises vacuum distillation which is carried out at a regeneration temperature (T r ) of at most 70°C and / or a pressure below the vapor pressure of the washing solvent (36) at the regeneration temperature (Tr). Method according to one of the preceding claims, characterized by the steps (i) drying the crushed material at a temperature not exceeding 60°C and a pressure not exceeding 300 hPa and (ii) separating film components, in particular plastic and / or metal foil components, before washing. Method according to one of the preceding claims, characterized by the step of pre-drying the comminution material after comminution, preferably before or after the separation of film parts, and before washing the comminution material, wherein the pre-drying is carried out in such a way that at least 50 percent by weight of the electrolyte solvent is removed. Method according to one of claims 1 to 6, characterized by the steps (a) drying the crushed material to produce dried crushed material, (b) separating plastic particles, in particular particles of shredded casing and / or shredded carrier film, from the dried shredded material so that black mass is obtained, (c) wherein the black mass is washed with the washing solvent (36). A method according to any one of the preceding claims, characterized by the step of, after washing the comminution material, dissolving the binder from the low-conducting salt comminution material with a binder solvent (60), so that low-binder comminution material is obtained. A method according to any one of the preceding claims, characterized by the step (i) Separating, in particular finely classifying, the comminution material, in particular the low-binder material, so that a graphic fraction and a transition metal fraction in which at least one transition metal is enriched compared to the graphite fraction are obtained. Method according to one of the preceding claims, characterized by the step of short-circuiting the batteries before comminuting the batteries until at least 75% of the galvanic elements have a regeneration cell voltage (llreg) of at most 0.2 volts, in particular at most 0.15 volts. Method according to one of the preceding claims, characterized in that the steps before washing the black mass (30) are carried out such that a conducting salt (38) of the alkali metal batteries (12) decomposes to a maximum of 2 percent by weight. Method according to one of the preceding claims, characterized in that (a) the shredded material (22) is not brought into contact with water before washing, (b) the conducting salt (38) is not decomposed, in particular not brought into contact with water and not heated and does not react with the washing solvent (36), (c) before and during comminution, the active material and / or an electrolyte present in the alkali metal batteries (12) is not brought into contact with water, (d) the alkali metal batteries (12), the crushed material and / or the black mass (30) are not pyrometallurgically treated before washing, in particular are not heated to more than 300°C, and (e) the comminution is carried out at a temperature which is so low that at most 2.5 mol percent of the fluorine, based on the comminution material (22), decomposes. Battery processing plant (10) for recycling alkali metal batteries (12), in particular Li batteries or Na batteries, with (a) a crushing plant (20) for crushing the batteries to obtain crushing material (22) containing black mass (30) containing the active material and the binder, (b) a washing device (34) which is designed and arranged to wash at least a fraction of the comminution material (22), in particular black mass (30), with a washing solvent (36), so that comminution material (22) with a low content of conductive salt and a washing liquid (40) are obtained, and (c) a regenerator (42) which (i) is designed to automatically regenerate washing solvent (36) from the washing liquid (40), (ii) a supply line connected to the washing device (34) for conducting washing liquid (40) from the washing device (34) to the regenerator (42), and (iii) a return line connected to the washing device (34) for conducting washing solvent (36) from the regenerator (42) to the washing device (34). Battery reconditioning system (10) according to claim 14, characterized in that the regenerator (42) is a vacuum distiller designed to automatically distill off a low-boiling fraction of the washing liquid (40), wherein the low-boiling fraction forms the washing liquid (40). Battery reconditioning system (10) according to claim 14 or 15, characterized by (a) a separating device (26) which is designed and arranged to separate black mass (30) from a residual fraction (32), which is arranged downstream of the comminution plant (20) in the material flow direction (M) and / or (b) a dryer (54) arranged downstream of the washing device (34) in the material flow direction (M). Battery processing plant (IO) according to claim 14 or 15, characterized by a pre-dryer (80) arranged downstream of the comminution plant (20) and upstream of the washing device (34) in the material flow direction (M). Battery processing plant (10) according to one of claims 14 to 16, characterized by a binder removal plant (58) arranged downstream of the washing device (34) in the material flow direction (M) and designed to automatically remove binder from the low-conductive salt comminution material (22) using a binder solvent (60). Battery processing plant (10) according to one of claims 14 to 18, characterized by a classifier for classifying the low-binder black mass to produce a graphite fraction and a transition metal fraction in which at least one transition metal is enriched compared to the graphite fraction, wherein the classifier is a fine classifier (66) having a classifying wheel (68).

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