METHOD FOR EXTRACTING RESIDUAL METALLIC LITHIUM FROM A COMBINATION OF ONE OR MORE ELECTRICAL STORAGE BATTERY CELLS

Abstract

The invention relates to a method for safely extracting residual lithium from an assembly of one or more energy storage battery cells, specifically electrochemical cells, containing residual solid lithium metal, as well as an integrated method for extracting lithium from an assembly of one or more energy storage battery cells, specifically electrochemical cells, containing residual lithium metal, performing the method of extracting residual lithium. The invention also relates to an apparatus for extracting residual lithium performing this method of extracting residual lithium.

Description

Method for extracting residual metallic lithium from a set of electrical energy storage cell(s)

[0001] The present invention relates to a method for extracting residual lithium from a set of electrical energy storage cell(s), in particular an electric battery, comprising residual solid metallic lithium, in a safe manner, as well as to an integral method for extracting lithium from a set of electrical energy storage cell(s), in particular an electric battery, comprising solid metallic lithium implementing said method for extracting residual lithium. It also relates to a residual lithium extraction unit implementing said method for extracting residual lithium.

[0002] The field of the invention is the field of solid lithium metal batteries, and in particular Lithium-Metal-Polymer batteries, and even more particularly the field of recycling these batteries. State of the art

[0003] Batteries based on solid lithium metal are known, such as Lithium-Metal-Polymer (LMP®) batteries. Safer and more energy-dense, these batteries are increasingly used, for example in the electric mobility and renewable energy storage sectors. As a result, the number of batteries based on solid lithium metal has been steadily increasing for several years, as has the number of batteries reaching the end of their life. However, even at the end of their life, a battery still contains solid lithium metal, which can be reused in other batteries or in other areas, and whose value is not negligible.

[0004] Today, the treatment of end-of-life lithium batteries has become a regulatory requirement. The new European battery regulation stipulates, among other things, the recycling of at least 65% of the battery's weight by 2026 and the recovery of at least 50% of the lithium contained in these batteries.

[0005] Also, recycling the valuable metals contained in these batteries, particularly metallic lithium, has become economically favorable due to the surge in the price of these metals. This price increase is due to the strong demand in the battery market for these energy transition metals.

[0006] In this context, there are currently very few techniques for recovering metallic lithium from an all-solid-state battery (i.e., recovering lithium at zero oxidation state present in an all-solid-state battery, particularly in the negative electrode). These rare techniques involve heating the battery to a temperature greater than or equal to the melting temperature of metallic lithium to recover the lithium in the liquid state. Other techniques involve grinding the battery in a controlled atmosphere (CO2, Ar, etc.) or in cryogenic conditions (e.g., at -150°C) to avoid the reaction of metallic lithium during grinding. However, these techniques present a risk of battery fire and the processing conditions are expensive and restrictive from an industrial point of view.Other methods are described for separating different metals (including lithium) present in positive electrode active materials of lithium-ion batteries. However, these methods are long and complex and involve lithium-ion batteries that have very different structures / materials and behaviors from those of lithium metal batteries. In particular, lithium metal in all-solid-state batteries behaves differently from lithium ion in lithium-ion batteries.

[0007] From international application WO2020 / 161339 A1 is known a method for recovering metallic lithium in an assembly of at least one electric battery cell comprising solid metallic lithium, said method comprising an extraction phase comprising the following steps: positioning said assembly in an orientation in which a first edge of said assembly from which one or more negative electrodes protrude is located below a second edge of said assembly, opposite said first edge, and from which one or more positive electrodes protrude; and heating said assembly to a temperature, called a treatment temperature, greater than or equal to the temperature of melting of said solid metallic lithium. The metallic lithium, once melted, is evacuated, all or part, naturally from each cell, under the effect of the force of gravity.

[0008] This solution is not entirely satisfactory, however, as the extraction of metallic lithium is not optimized. In particular, the batteries obtained include lithium residues that remain stuck to the battery components at the end of this operation. Thus, the battery cells resulting from this process cannot be treated by conventional battery recycling processes and the cathode contained in the cells cannot be recovered.

[0009] An aim of the present invention is to remedy this drawback.

[0010] Another aim of the invention is to propose a method for recovering residual solid metallic lithium in an assembly of at least one electrical energy storage cell, in a simple manner.

[0011] Another aim of the invention is to propose a method for recovering residual solid metallic lithium in an assembly of at least one electrical energy storage cell, in an efficient manner by limiting and controlling the effect of potential short circuits during recycling.

[0012] Another aim of the invention is to propose a method for recovering residual solid metallic lithium in a set of at least one electrical energy storage cell while guaranteeing recycling of all or part of the liquids and solids used in said method. Statement of the invention

[0013] The first subject of the invention is a method for extracting residual lithium from a set of electrical energy storage cell(s) comprising residual solid metallic lithium, said method comprising at least the following steps: i) immersion of said set in an aqueous composition, ii) separation of the solids (and / or solid residues) from the aqueous composition, Hi) adding at least one acid or one of its precursors capable of forming at least one lithium salt insoluble in the aqueous composition, and iv) recovering the lithium salt.

[0014] The method according to the invention proposes to recover the residual solid metallic lithium from a set of electrical energy storage cell(s), by treating the cell(s) of said set individually or together.

[0015] In the present invention, the term "solid metallic lithium" or "solid metal lithium" means solid lithium with zero oxidation state.

[0016] Furthermore, the method according to the invention proposes to recover, in the form of at least one salt, the residual solid metallic lithium from a set of electrical storage cell(s), by immersing said set in an aqueous composition in order to dissolve the residual solid metallic lithium, then by reacting said dissolved lithium with an acid to form a salt insoluble in the aqueous composition which can then be easily recovered.

[0017] Thus, the method according to the invention allows a simple and uncomplicated recovery of residual solid metallic lithium.

[0018] Furthermore, the method according to the invention provides reuse of the aqueous composition for one or more subsequent closed-loop residual solid metallic lithium recovery processes.

[0019] In the present application, each electrical energy storage cell of the set of cell(s) preferably comprises residual solid metallic lithium.

[0020] In the present application, the expression "each cell comprises residual solid metallic lithium" means that each electrical energy storage cell implemented in step i) is at least partially delithiated.

[0021] According to a preferred embodiment, each electrical energy storage cell comprises: - residual solid metallic lithium, in the form of a layer and / or debris, in particular from the negative electrode, - a positive electrode, in particular in the form of a layer, - a solid or quasi-solid electrolyte comprising a lithium salt, in particular in the form of a layer, said solid or quasi-solid electrolyte being arranged next to the positive electrode, and - a current collector associated with and / or next to the positive electrode. In other words, said assembly preferably comprises residual solid metallic lithium (from a plurality of negative electrode films or layers), and a plurality of solid or quasi-solid electrolyte films or layers, positive electrodes, and current collectors.

[0022] In the present application, the "residual solid metallic lithium" may comprise: residual pure metallic lithium; or at least one residual metallic lithium alloy; or a combination of residual pure metallic lithium and at least one residual metallic lithium alloy.

[0023] The assembly implemented in step i) may comprise a single electrical energy storage cell or several electrical energy storage cells.

[0024] When the assembly comprises several cells (e.g. at least two cells), they are preferably assembled, or in particular stacked, in an assembly direction. The assembly direction may be perpendicular to the plane formed by each electrical energy storage cell.

[0025] The assembly implemented in step i) preferably corresponds to an electric battery, and particularly preferably in which several cells are connected in series.

[0026] The assembly implemented in step i) comprises residual solid metallic lithium. According to a preferred embodiment of the invention, the residual solid metallic lithium represents in the assembly of cell(s) implemented in step i) at most 20% by mass, preferably at most 15% by mass, and particularly preferably at most plus approximately 10% by mass, relative to the total mass of solid metallic lithium present in a set of non-delithiated cell(s).

[0027] Step i): immersion of said assembly in an aqueous composition

[0028] This step dissolves the residual solid metallic lithium in the aqueous composition. It is also referred to as the residual solid metallic lithium dissolution step.

[0029] The assembly is immersed in the aqueous composition. In other words, the amount of aqueous composition is such that it completely covers said assembly. When the assembly comprises several electrical energy storage cells, all the cells are preferably immersed in the aqueous composition.

[0030] The aqueous composition preferably comprises at least 90% by mass of water, and particularly preferably at least 95% by mass of water, relative to the total mass of aqueous composition. More particularly preferably, the aqueous composition consists solely of water.

[0031] The aqueous composition before immersion (i.e. before step i)) preferably has a neutral pH, i.e. ranging from 6.5 to 7.5, and particularly preferably is close to 7.

[0032] Step i) may be carried out by means of a container or soaking tank comprising the aqueous composition. During step i), the set of electrical storage cell(s) is then in the tank or soaking container, and covered by the aqueous composition.

[0033] Step i) preferably lasts at least 30 min, and preferably 1 to 2 hours. The duration of step i) will depend on the number of cells in the set and / or the size of the cells, and in particular on the presence or absence of prior steps of cutting and / or grinding the cells as described below. Dissolution is favored when the size of the cells used in the aqueous composition is reduced.

[0034] The method may further comprise, during step i), stirring the aqueous composition. This thus makes it possible to improve the kinetics of delithiation. Mechanical agitation may be used. Step i) may be carried out with one or more agitation means, such as a shaft equipped with a mechanical agitation rotor.

[0035] The method may further comprise, during step i), heating the aqueous composition. This thus makes it possible to improve the delithiation kinetics. Step i) may be carried out with one or more heating means, such as, for example, a reactor equipped with a double wall through which a fluid circulates to heat the aqueous composition. The heating may be carried out at a temperature ranging from approximately 40°C to approximately 70°C. The heating may be started before immersing the assembly, i.e. before step i).

[0036] Step i) preferentially leads to the delamination of the film(s) / layer(s) of solid or quasi-solid electrolyte, positive electrode and current collector. In other words, this step i) also allows the delamination of the layers or films of the different cells forming the assembly. Thus, the layers or films of the different cells forming the assembly separate during step i).

[0037] Step ii) solid / liquid separation

[0038] The method comprises, between steps i) and iii), a step ii) of separating the solids (and / or solid residues) from the aqueous composition. This step ii) makes it possible to avoid overconsumption of acid during the following step iii). Furthermore, at the end of step i), the positive electrode of the cell is not soluble in the aqueous composition and must be separated from the aqueous composition before step iii) in order to avoid contaminating the lithium salts with positive electrode residues and complicating the recovery of the lithium salts during step iv).

[0039] In step ii), solids (and / or solid residues) are separated from the aqueous composition, in particular solids (and / or solid residues) are removed or taken out of the soaking tank or container. Step ii) may be carried out with one or more means for separating the solids and / or solid residues from the aqueous composition, such as filtration, e.g. using a filter press, or centrifugation, e.g. using a centrifuge.

[0040] Step ii) may comprise or be followed by a step ii') of washing said solids (and / or solid residues), preferably with water. Washing ii') is preferably carried out above the aqueous composition, and in particular above the soaking tank or container. This thus makes it possible to improve the yield of the process in recovered lithium salts. Alternatively, washing step ii') may be carried out by injecting clean water during filtration and in particular into the filter press. Step ii') may therefore be concomitant with step ii).

[0041] Indeed, at the end of step i), the aqueous composition comprises insoluble particles and / or solid elements (called solids and / or solid residues) in the aqueous composition (active material of positive electrode, current collector, etc.). Step ii) then makes it possible to eliminate these solids. These solids are preferably active materials of positive electrodes and / or current collectors. In other words, during this step ii), at least the active materials of positive electrodes and / or the current collectors (also called "black mass") are separated as solids from the aqueous composition. The resulting aqueous composition then comprises the dissolved residual lithium and optionally one or more polymers of the dissolved electrolyte.

[0042] Step ii) (and step ii') if it exists) thus makes it possible to obtain an aqueous composition free of solids, and to guarantee that all the residual lithium is present in said aqueous composition.

[0043] Step iii): addition of at least one acid or one of its precursors capable of forming at least one lithium salt insoluble in the aqueous composition

[0044] Step iii) consists of reacting the residual solid metallic lithium dissolved in the aqueous composition with said acid to form a lithium salt insoluble in the aqueous composition. This step iii) thus makes it possible to promote the following step iv) of recovery of the lithium salt.

[0045] Preferably, the acid or one of its precursors is chosen from mineral acids, such as for example phosphoric acid or carbonic, carboxylic acids, such as acetic acid, and a mixture thereof.

[0046] In step i), immersion of the assembly in the aqueous composition leads to the dissolution of the lithium and an increase in the pH of the aqueous composition (which may reach a pH greater than or equal to 13). In step iii), the pH of the aqueous composition decreases. Preferably, the acid or one of its precursors is added in sufficient quantities to precipitate all of the lithium present in the aqueous composition.

[0047] According to a preferred embodiment of the invention, the aqueous composition at the end of step iii) has a neutral pH, i.e. ranging from 6.4 to 7.6, and particularly preferably from 6.5 to 7.5, and more particularly preferably close to 7. This thus makes it possible to reuse this aqueous composition for soaking a new set of cells. The aqueous composition can thus be used in a closed loop.

[0048] In step iii), the aqueous composition is analyzed, for example by ICP-AES, to measure the mass concentration of Li (in g / L). The mass concentration of Li in the aqueous composition is adjusted. It can range from 2 to 30 g / L (depending on the quantity of cells immersed), and preferably from 5 to 20 g / L.

[0049] The acid or its precursor is added to the aqueous composition at a rate of at least 10 g / L, and particularly preferably from 10 g / L to 500 g / L of aqueous composition (depending on the acid used).

[0050] Step iii) preferably lasts at least 10 minutes, and preferably from 10 to 60 minutes. The duration of step iii) will depend on the quantity of residual lithium to be reacted with the acid or its precursor, the acid used, the volume of the aqueous composition and / or the temperature of the mixture.

[0051] The method may further comprise, during step iii), stirring the aqueous composition. This thus makes it possible to improve the kinetics of formation of the lithium salts. Mechanical stirring may be used. The stirring means may be those as described for step i).

[0052] The method may further comprise, during step iii), heating the aqueous composition. This thus makes it possible to improve the kinetics of formation of the lithium salts and the recovery yield of the salts. The heating may be started before adding the acid or its precursor, i.e. before step iii). The heating may be carried out using a reactor as described for step i) above. In particular, the heating makes it possible to reduce the solubility of the Li salts in the aqueous composition and thus improve the recovery yield of the dissolved Li.

[0053] Heating may be carried out at a temperature ranging from about 50°C to about 100°C, and preferably between 70°C and 90°C.

[0054] At the end of step iii), the aqueous composition comprises at least one lithium salt insoluble therein. In other words, the lithium salt is in a solid form in the aqueous composition (i.e. in the form of solid particles dispersed in the aqueous composition). The solid aspect can be detected visually or by a spectroscopic method such as for example by the absorption of UV-Visible light.

[0055] Step iv): recovery of the lithium salt(s)

[0056] Step iv) can be carried out by filtration or centrifugation. At the end of step iv), the lithium salts are separated from the aqueous composition.

[0057] Step iv) may be carried out with one or more solid / liquid separation means, such as a filter press or a centrifuge.

[0058] Thanks to steps i), ii), iii) and iv), it is possible to recover the residual solid metallic lithium initially present in the set of cell(s), in the form of salts. Furthermore, at the end of step iv), the lithium salt(s) are separated from the aqueous composition, which makes it possible to reuse the aqueous composition in a new process for extracting residual solid metallic lithium, and in particular during a new step i).

[0059] Step v) washing the lithium salts

[0060] The method may further comprise a step v) of washing the lithium salt(s) obtained at the end of step iv). The rinsing or washing can be carried out with water. Washing is preferably carried out above the aqueous composition, and in particular above the soaking tank or container. Alternatively, step v) of washing can be carried out by injecting clean water during filtration, and in particular into the filter press. Step v) makes it possible in particular to improve the purity of the lithium salts obtained.

[0061] Step vi) drying of lithium salts

[0062] The method may further comprise a step vi) of drying the lithium salt(s) obtained at the end of step iv) or v). The drying may be carried out at a temperature ranging from approximately 60°C to approximately 100°C. Step vi) may be carried out with one or more means for drying the lithium salts, such as an oven or a heating tunnel.

[0063] Steps a) and b) of cutting and grinding the cells before step i)

[0064] The method may further comprise, before step i), a step a) of cutting the set of cell(s), and preferably all the cells in the set. This thus makes it possible to reduce the dissolution time of the lithium during step i) and to improve the following step ii) of separating the solids from the aqueous composition. According to this embodiment, step i) is then carried out with a set of cut cell(s) or with one or more cut cell(s). Step a) may be carried out with one or more cutting means, such as a metal cutter, a laser cutting machine, or an ultrasonic cutting machine. The cutting step a) is a dry cutting step.

[0065] The method may further comprise, before step i), a step b) of grinding the set of cell(s), and preferably all the cells in the set. This thus makes it possible to reduce the dissolution time of the lithium during step i) and to improve the following step ii) of separating the solids from the aqueous composition. According to this embodiment, step i) is then carried out with a set of ground cell(s) or with one or more ground cell(s). Step b) may be carried out with one or more grinding means, such as a jaw crusher or a disc crusher. The grinding means may be equipped with a system of cooling to prevent the material from heating up during grinding in order to reduce industrial risk. Grinding step b) is a dry grinding step.

[0066] Step b) is preferably carried out after step a). According to this embodiment, step i) is then carried out with a set of cut and ground cell(s) or with one or more cut and ground cell(s).

[0067] Step c) of oxidation of residual lithium from the cells before step i)

[0068] The process may further comprise, before step i), a step c) of oxidation of the residual lithium to lithium oxide (U2O). This thus makes it possible to avoid the generation of too large a quantity of hydrogen during step i). In particular, step c) makes it possible to reduce the reactivity of the lithium before implementing step i), and thus to reduce the industrial risk.

[0069] Step c) may be carried out by heating the cell assembly(s), preferably to a temperature ranging from about 300°C to about 400°C. Step c) may be carried out with one or more heating means, such as an oven, a furnace or a heating tunnel.

[0070] Step c) can last from about 30 minutes to about 2 hours.

[0071] Step c) can be carried out without prior steps a) and / or b), or in association with steps a) and / or b). Preferably, step c) is carried out after a grinding step b), in particular in order to accelerate the oxidation kinetics of the metallic lithium.

[0072] The process, and in particular steps i), i'), ii), ii'), iii) and iv), can be repeated with other sets of cells, preferably with the aqueous composition from step iv) of the previous process. This allows it to be recycled. The process is preferably carried out at atmospheric pressure, and in ambient air. In other words, inert atmosphere conditions are not necessary.

[0073] Step d) purification of the aqueous composition

[0074] The method may further comprise a step d) during which the aqueous composition comprising dissolved lithium is purified. This thus makes it possible to eliminate all the soluble compounds in the aqueous composition resulting from step ii) or ii'), except lithium. Among these soluble compounds, mention may be made of the solid or quasi-solid electrolyte or its derivatives. In particular, at the end of step ii) or ii'), the solid or quasi-solid electrolyte is at least partly dissolved in the aqueous composition. An aqueous composition is then obtained comprising the solid electrolyte or one of its derivatives, and the residual lithium.

[0075] Step d) is preferably carried out by solid / liquid separation. Particularly preferably, step d) is carried out by hot filtration or hot centrifugation, and more particularly preferably at a temperature ranging from approximately 70°C to approximately 90°C. During step d), the solid or quasi-solid electrolyte becomes insoluble in the aqueous composition when hot and can be easily separated by filtration from the lithium still soluble in the aqueous composition. Step d) can be carried out with one or more solid / liquid separation means, such as a filter press or a centrifuge.

[0076] Step d) makes it possible to avoid overconsumption of acid or one of its precursors during step iii), and also to improve the purity of the salts obtained in step iv).

[0077] The method may further comprise, after step i) and before step ii), a step i') of adding at least one anti-foaming agent to the aqueous composition. Indeed, the immersion step i) may lead to the formation of a thick foam which may itself lead to liquid overflows and require stopping step i). The use of the anti-foaming agent makes it possible to avoid this. Different types of anti-foaming agents may be used, such as alcohol- and fatty acid-based anti-foaming agents such as the anti-foaming agent marketed under the reference "RM 761" (manufactured by Karcher) or polydimethylsiloxane-based anti-foaming agents such as the anti-foaming agents marketed under the references "CQ-232", "CQ-233", "CQ-234" (manufactured by NANHUI NEW MATERIAL CO., LTD).

[0078] The second subject of the invention is a method for the complete extraction of lithium from a set of electrical energy storage cells comprising solid metallic lithium, said method comprising: A) a first method for extracting lithium from a set of electrical energy storage cells, each cell comprising a negative electrode containing solid metallic lithium, a positive electrode, a solid or quasi-solid electrolyte, and optionally a current collector, said set of cells comprising a first edge from which the negative electrode(s) of said cell(s) protrude and a second edge, opposite said first edge, and from which the positive electrode(s) protrude, said method comprising an extraction phase comprising the following steps: - positioning said assembly in an orientation in which one of said first and second edges is below the other of said first and second edges, and - heating said assembly to a temperature, called treatment temperature, greater than or equal to the melting temperature of said solid metallic lithium, said first extraction method leading to a set of electrical energy storage cell(s) comprising residual solid metallic lithium, and B) a second method for extracting residual lithium in accordance with the first subject of the invention.

[0079] The first method according to A)

[0080] When the assembly comprises several cells (i.e. at least two cells), each cell comprises a positive electrode, a negative electrode containing solid metallic lithium, a solid or quasi-solid electrolyte, and possibly a current collector, said assembly comprising a first border from which the negative electrodes of said cells protrude and a second border, opposite said first border, and from which the positive electrodes protrude. In this embodiment embodiment, said first method preferably further comprises a step of cutting the electrical connection between the positive electrodes of at least two, and in particular of all, the cells of said assembly.

[0081] Each electrical energy storage cell preferably comprises: - a negative electrode containing solid metallic lithium, in particular in the form of a layer, - a positive electrode, in particular in the form of a layer, - a solid or quasi-solid electrolyte comprising a lithium salt, in particular in the form of a layer, said solid electrolyte being arranged between the positive electrode and the negative electrode, and - a current collector associated with and / or next to the positive electrode.

[0082] In the first method according to A), the “solid metallic lithium” may comprise: pure metallic lithium; or at least one metallic lithium alloy; or a combination of pure metallic lithium and at least one metallic lithium alloy.

[0083] The assembly implemented may comprise a single or single electrical energy storage cell or several electrical energy storage cells, preferably assembled, or in particular stacked, in an assembly direction. The assembly direction may be perpendicular to the plane formed by each electrical energy storage cell.

[0084] According to a preferred embodiment of the invention, the assembly corresponds to an electric battery, and particularly preferably in which the cells are connected in series.

[0085] The assembly used in the method according to A) comprises solid metallic lithium. According to a preferred embodiment of the invention, the solid metallic lithium represents in the assembly of cell(s) used in the method according to A) at least 80% by mass, preferably at least 85% by mass, and particularly preferably at least approximately 90% by mass, relative to the total mass of solid metallic lithium present in a set of undelithiated cell(s).

[0086] The first method according to A) makes it possible to extract the vast majority of the solid metallic lithium from the set of cell(s) so as to leave only residual solid metallic lithium. The second method according to B) is in accordance with the first object of the invention and makes it possible to extract all of the residual solid metallic lithium.

[0087] Where the “solid metallic lithium” comprises a combination of different forms of lithium, such as those indicated above, having different melting temperatures, then the step of heating the assembly of cell(s) is carried out at a processing temperature greater than or equal to: - the lowest of said different melting temperatures; and - preferably, the highest of said different melting temperatures.

[0088] Thus, the first method according to A) proposes to recover the solid metallic lithium from an assembly by heating said assembly to a treatment temperature greater than or equal to the melting temperature of the solid metallic lithium. The metallic lithium, once melted, is evacuated, in whole or in part, naturally from each cell. Thus, the first method according to A) allows a simple and uncomplicated recovery of the vast majority of the solid metallic lithium.

[0089] Furthermore, the first method according to A) proposes a specific orientation of each cell, the latter being, at a minimum, inclined. Such an orientation of each cell makes it possible to facilitate the flow of molten lithium out of the cell by gravity.

[0090] Furthermore, and above all, the first method according to A) preferably provides for cutting the connection between the positive electrodes of at least two, more preferably, of all the cells of the assembly. In other words, the cutting step makes it possible to break the electrical connection between the positive electrodes of the cells of the assembly. Thus, after the cutting step, the assembly comprises a plurality of cells which are no longer electrically connected to each other, which reduces the reactivity of the assembly, and therefore the risk of fires during lithium recovery.

[0091] The first border can be characterized by the fact that it defines the side through which the lithium, once in the liquid state, must flow.

[0092] The first method according to A) can be implemented to treat several sets of cell(s), in particular several sets of cell(s) forming a battery pack and connected to each other in parallel within said battery pack.

[0093] At least two sets of cell(s) can be aligned side by side, without overlapping, for example in a direction parallel to the first border.

[0094] Heating

[0095] According to a non-limiting example of embodiment, the treatment temperature is greater than or equal to 180.5°C.

[0096] According to an exemplary embodiment, the treatment temperature is less than or equal to a maximum temperature, for example 300°C.

[0097] Heating can be done using hot plates or a heating enclosure.

[0098] Cut

[0099] The cutting step can be performed: - by cutting connecting wires between the positive electrodes along a cutting line located at the level, and in particular at the limit, of the second edge, on the side of said electrical connecting wires; or - by cutting the cells along a cutting line located at the level, and in particular at the limit, of the second border, on the side of said cells.

[0100] The first alternative allows solid metallic lithium to be retained, or not removed, from the assembly when the bonds are cut. electrical, which improves lithium recovery efficiency.

[0101] In this first alternative, the cutting of the connecting wires must be close enough to the second edge so that after cutting there is no longer any contact between the different positive electrodes.

[0102] In the second alternative, in order to reduce the amount of lithium lost, the cut must be in the immediate vicinity of the second edge.

[0103] For example, the cut can be made at a distance “d” from the second edge less than or equal to 2 mm, or less than or equal to 1% of the dimension of the cells between the first and second edges of the battery.

[0104] The cutting step can be done by guillotine.

[0105] In this case, the assembly is inserted into a paper cutter of suitable size and power.

[0106] The cutting step can be carried out before the start of the heating step or after the start of the heating step. In the latter case, preferably, the cutting step can be carried out before the solid lithium metal begins to melt.

[0107] The cutting step can be performed before the positioning step, after the positioning step, or during the positioning step.

[0108] Electric charging

[0109] According to a particularly advantageous characteristic, the first method according to A) can further comprise, before the extraction phase, a step of electrically charging the set of cell(s), said extraction phase being applied to said charged set.

[0110] Electrically charging the cell assembly and performing the extraction phase on the electrically charged cells increases the lithium extraction yield. Indeed, electrically charging a cell moves the lithium ions towards the negative electrode, which increases the amount of recoverable lithium.

[0111] Each cell can be charged individually, or by electrically charging the entire cell(s).

[0112] Compression

[0113] According to a particularly advantageous embodiment, the extraction phase may further comprise a step of compressing the set of cell(s).

[0114] This forces the molten lithium out of each cell, increasing the amount of lithium recovered.

[0115] The compression step can be carried out continuously throughout the extraction phase; or discretely, one or more times, during the extraction phase. In the first case, each cell is subjected to compression, in part or in full, for the entire duration of the extraction phase. In the second case, the extraction phase includes moments when the set of cell(s) is not subjected to compression.

[0116] Advantageously, the compression step may apply compression to the surface of the cell assembly(s) by sweeping the surface of the cell assembly(s) from the second edge to the first edge. Thus, the molten lithium is gradually brought / guided to the first edge from which one or more negative electrode(s) protrude, which increases the amount of lithium recovered and reduces the risk of contact between the lithium and the positive electrode(s).

[0117] For example, the compression step can be carried out by passing the set of cell(s) between two rollers or by means of a compression roller compressing the set of cell(s) against a support surface.

[0118] Compression can be applied in successive passes, each pass sweeping the surface of the cell assembly(s) starting from the second edge toward the first edge.

[0119] The space between the compression rollers, respectively between the compression roller and the support surface, may correspond to the thickness of the cell assembly(s) minus the thickness of the solid lithium metal layers. This allows compression to be applied, as long as there is still solid lithium in the cell assembly(s).

[0120] The space between the two compression rollers, respectively between the compression roller and the support surface, can be reduced with successive passes, so as to always apply compression to the entire cell(s).

[0121] The speed of passage between the compression rollers, respectively of the compression roller, and more generally the scanning speed, can be between a few mm to a few tens of mm, per second.

[0122] Removal of connectors and overflows

[0123] Furthermore, the first method according to A) may comprise, before the extraction phase, a step of removing at least one electrical connector from the set of cell(s), also called a “crimp” in English. This makes it easier to process the set of cell(s).

[0124] Furthermore, the first method according to A) may comprise, before the extraction phase, a step of removing the overflows of material at the level of at least one, and particularly each, edge of the set of cell(s).

[0125] Positioning

[0126] According to a first version, the positioning step can perform a positioning of the set of cell(s) in an orientation in which the first border of the set of cell(s) is located below the second border of the set of cell(s).

[0127] Such an orientation of the cell assembly(s), and therefore of each cell of the cell assembly(s), makes it possible on the one hand to facilitate the flow of molten lithium out of the cell by gravity, and on the other hand to avoid contact between the molten lithium and the positive electrodes or the current collector of the positive electrode, such contact being able to cause a short- electrical circuit or an electric arc, such a short circuit being able to cause a fire.

[0128] According to a preferred embodiment of this first version, the positioning step can achieve a vertical positioning of the set of cell(s), in which the first border is located downwards.

[0129] This improves the flow of molten lithium out of each cell by gravity.

[0130] In addition, the risk of contact between the molten lithium and the positive electrode(s) is reduced, or even zero.

[0131] Preferably, in this first version, the step of heating the entire cell(s) can be carried out under inert gas. Thus, the method according to the invention reduces the risk of accidents, in particular the risk of fire. In addition, the formation of polluting compounds which can be generated by unwanted, or even uncontrolled, physicochemical reactions during lithium extraction is avoided.

[0132] According to a non-limiting exemplary embodiment, the inert gas may be, or comprise, any of the following gases: helium (He), neon (Ne), argon (Ar), krypton (Kr), xenon (Xe) and radon (Rn).

[0133] According to another embodiment of this first version, the step of heating the assembly of cell(s) can be carried out under vacuum.

[0134] According to another embodiment of this first version, the step of heating the assembly of cell(s) can be carried out in dry air, in particular containing less than 0.002% by mass of H2O.

[0135] According to a second version, the positioning step can carry out a positioning of the set of cells in an orientation in which the first edge of the set of cells is located above the second edge of the set of cells. In this case, the extraction phase further comprises, before the heating step, a step of immersing the set of cells in a liquid, called a treatment liquid, denser than liquid lithium and electrically insulating.

[0136] This second version proposes a specific orientation of each cell, the latter being at least inclined, so that the first edge from which the negative electrode(s) protrude is located above the level of the second edge, opposite the first edge, from which the positive electrode(s) protrude. Such an orientation of each cell makes it possible, on the one hand, to facilitate the flow of molten lithium out of the cell by difference in density, and on the other hand to avoid contact between the molten lithium and the positive electrodes or the current collectors of the positive electrodes, such contact being able to cause an electrical short circuit, such a short circuit being able to cause a fire. In addition, immersing the entire cell(s) in a liquid makes it possible to improve the dissipation of calories from the cell, in particular during a short circuit and therefore to greatly limit its effect.

[0137] In this application, "density" means the ratio between the density of the liquid considered and the density of water.

[0138] According to a preferred embodiment of this second version, the positioning step can bring about a vertical positioning of the set of cell(s), in which the second border is located downwards.

[0139] Thus, the flow of molten lithium out of each cell, due to the difference in density, is improved.

[0140] In addition, the risk of contact between molten lithium and the positive electrodes is reduced, or even zero.

[0141] Preferably, the immersion step can be carried out by immersing the entire cell(s) completely in the treatment liquid.

[0142] The liquid can be a natural or synthetic oil, with the following physicochemical properties: - hydrophobic and non-reactive towards lithium, - electrical insulator, - having a density greater than that of lithium, - thermally stable beyond the melting temperature of lithium, i.e. 180.5°C, - a flash point, as well as an auto-ignition point, as high as possible.

[0143] The invention also has as a third subject a unit for extracting residual lithium from a set of electrical energy storage cell(s) comprising residual solid metallic lithium, characterized in that it comprises: - a tank for soaking the entire cell(s) in an aqueous composition; - one or more means for separating solids (and / or solid residues) from the aqueous composition; - a means of adding acid or one of its precursors to the aqueous composition; and - one or more means of solid / liquid separation for the recovery of the lithium salt(s).

[0144] The extraction unit in accordance with the third object makes it possible to implement the method in accordance with the first object of the invention.

[0145] The means of adding acid or one of its precursors to the aqueous composition may be a diaphragm metering pump. This allows the introduction of a precise volume of the acid solution or its precursors, previously prepared in a tank, depending on the concentration of lithium present in the aqueous composition.

[0146] The solid / liquid separation means for the recovery of lithium salts may be as defined in the first subject of the invention.

[0147] The residual lithium extraction unit may further comprise a heating means and / or a means of stirring the aqueous composition as defined in the first subject of the invention.

[0148] The residual lithium extraction unit may further comprise a means for washing the lithium salts and / or a means for washing the entire cell(s) to implement the washing steps described above of the method in accordance with the first subject of the invention.

[0149] The residual lithium extraction unit may further comprise one or more means for recovering the aqueous composition to reinject it into the soaking tank (in order to implement a new process in accordance with the first subject of the invention). This thus makes it possible to recycle the aqueous composition in a closed circuit.

[0150] Generally, the residual lithium extraction unit may comprise means configured to implement any combination of at least one of the characteristics described in the first subject of the invention, and which are not repeated here in detail for the sake of brevity.

[0151] The fourth subject of the invention is an integral installation for extracting lithium from a set of electrical energy storage cell(s), each cell comprising a positive electrode, a negative electrode comprising solid metallic lithium, a solid or quasi-solid electrolyte, and possibly a current collector, said assembly comprising a first edge from which the negative electrode(s) of said cell(s) protrude and a second edge, opposite said first edge, and from which the positive electrode(s) protrude, said extraction installation comprising: * a lithium extraction unit leading to a set of cell(s) comprising residual solid metallic lithium, said lithium extraction unit containing: - means for positioning said assembly in an orientation in which one of said first and second edges is below the other of said first and second edges; and - a heating means configured to heat said assembly to a temperature, called treatment temperature, greater than or equal to the melting temperature of said solid metallic lithium, and * a residual lithium extraction unit in accordance with the third subject of the invention.

[0152] Said lithium extraction unit may further comprise a means for cutting the electrical connection between the positive electrodes of at least two, and in particular of all, the cells of said assembly.

[0153] Generally, the installation may comprise means configured to implement any combination of at least one of the characteristics described in the second subject of the invention, and which are not repeated here in detail for the sake of conciseness.

[0154] For example, the cutting means may include a paper cutter.

[0155] In particular, the heating means may comprise an oven (heating enclosure) or heating plates.

[0156] Advantageously, the oven can be filled with an inert gas, dry air or be placed under vacuum, or even be filled with a treatment liquid denser than liquid lithium.

[0157] Said lithium extraction unit may further comprise a means for compressing said assembly.

[0158] The compression means may comprise at least one roller.

[0159] In particular, the compression means may comprise a single roller compressing the assembly of cell(s) against a bearing surface. The bearing surface may be heated to accelerate the temperature rise of the assembly of cell(s).

[0160] Alternatively, the compression means may comprise two rollers between which the set of cell(s) is passed.

[0161] Generally, the compression means can be configured to apply continuous compression throughout the extraction phase.

[0162] Alternatively, the compression means may be configured to apply compression discretely in time, one or more times, during the extraction phase. In this case, the extraction phase includes times when the set of cell(s) is not subjected to compression.

[0163] Advantageously, the compression means may be configured to apply compression, of constant or variable value, progressively or by sweeping over the surface of the set of cell(s), from the second edge to the first edge. Thus, the molten lithium is gradually brought / guided towards the first edge in the lower position, which increases the quantity of lithium recovered and reduces the risk of contact between the lithium and the positive electrodes.

[0164] When using one or two compression rollers, compression may be applied to the assembly in successive passes. Each pass applies sweeping compression across the surface of the assembly, from the second edge to the first edge. At the end of each pass, compression may be stopped by moving the rollers apart or the roller away from the support surface, and then returned to the second edge for a new pass.

[0165] The distance between the rollers, respectively between the compression roller and the support surface, can be reduced as the passes progress, and in particular between two successive passes.

[0166] Compression may be applied to at least two sets of cell(s) by the same compression means, namely a set of rollers, or a roller cooperating with a bearing surface. Description of figures and examples

[0167] Other advantages and characteristics will appear on examining the detailed description of embodiments which are in no way limiting, and the appended drawings in which: Figure 1 is a schematic representation of a first example of embodiment of the method in accordance with the first subject of the invention; Figure 2 is a schematic representation of a second exemplary embodiment of the method according to the first subject of the invention; Figure 3 is a schematic representation of an exemplary embodiment of a method according to the second subject of the invention.

[0168] It is understood that the embodiments which will be described below are in no way limiting. In particular, it will be possible to imagine variants of the invention comprising only a selection of characteristics described below, isolated from the other characteristics described, if this selection of characteristics is sufficient to confer a technical advantage or to differentiate the invention compared to the state of the prior art. This selection includes at least one preferably functional characteristic without structural detail, or with only a part of the structural details if this part is only sufficient to confer a technical advantage or to differentiate the invention compared to the state of the prior art.

[0169] In the figures, elements common to several figures retain the same reference.

[0170] The method according to the first subject of the invention, shown in Figure 1, comprises a first step i), of immersing in an aqueous composition, preferably water, a set of cell(s), each cell comprising residual solid metallic lithium, a positive electrode, a current collector associated with the positive electrode, and a solid or quasi-solid electrolyte. This step i) makes it possible to dissolve the residual solid metallic lithium in the aqueous composition. The method may further comprise a step i') of adding at least one antifoaming agent to the aqueous composition. Step i') is as defined in the invention. Once the dissolution is complete, a step ii) of solid / liquid separation is carried out to separate the solids and solid residues from the aqueous composition. The solids and solid residues are for example removed or taken out of the aqueous composition.Step ii) may also comprise a step ii') of washing or rinsing said solids (or solid residues), preferably with water. Washing is preferably carried out above. of the aqueous composition, and in particular above the soaking tank. This thus makes it possible to improve the yield of the process in recovered lithium salt(s). Once the solids and solid residues have been removed from the aqueous composition, an acid such as phosphoric acid or a stream of CO2 (carbonic acid precursor) is added to the aqueous composition according to a step iii), so as to form one or more lithium salts insoluble in the aqueous composition. The following step iv) consists of recovering the lithium salts formed, by solid / liquid separation, preferably by filtration.

[0171] The method according to the first subject of the invention, shown in Figure 2, comprises the aforementioned steps i), i'), ii), ii'), iii) and iv) as described above for Figure 1 and further comprises, prior to step i), any one of steps a), b), c) or a combination of at least two of steps a), b), c). These steps are optional. According to Figure 2, a set of cell(s), each cell comprising residual solid metallic lithium, a positive electrode, a current collector associated with the positive electrode, and a solid or quasi-solid electrolyte, is cut according to a step a), so as to obtain lamellae or pieces of cell(s) and to improve the dissolution of the lithium in the aqueous composition during step i).Step a) may be followed by a step b) during which the cut assembly is ground, so as to obtain a set of ground cell(s) and to further improve the dissolution of lithium in the aqueous composition during step i). Step b) may be followed by a step c) of heating the assembly in order to oxidize the residual lithium. This step c) avoids the generation of too large a quantity of hydrogen during step i). The method may further comprise step i') of adding at least one anti-foaming agent to the aqueous composition. Step i') is optional and is as defined in the invention.

[0172] The process of Figure 2 then comprises step i) as described for Figure 1, then optionally step i'), followed by steps ii) of solid / liquid separation and ii') of washing as described for Figure 1.

[0173] The aqueous composition obtained at the end of steps ii) and ii') can be purified according to a step d), so as to eliminate all the compounds soluble in the aqueous composition, except lithium. This step d) is preferably carried out by solid / liquid separation, and more particularly by hot filtration. During step d), the solid or quasi-solid electrolyte and / or its derivatives become insoluble in the aqueous composition when hot and can be easily separated, by filtration, from the lithium still soluble in the aqueous composition.

[0174] The process of Figure 2 then comprises steps iii) and iv) as described for Figure 1, optionally followed by a step v) of washing the lithium salts. These can optionally be dried according to a step vi).

[0175] The method according to the second subject of the invention, shown in Figure 3, comprises, prior to the method according to the first subject of the invention (method according to B)), shown in Figures 1 and 2, a method for extracting the vast majority of solid metallic lithium from a set of cell(s), each cell comprising a negative electrode comprising solid metallic lithium, a positive electrode, possibly a current collector, and a solid or quasi-solid electrolyte (method according to A)). Such a method according to A) comprises an optional step during which the electrical connectors, and in particular the current concentrators also called "crimps" in English, of the battery, are removed.

[0176] In a subsequent, optional step, excess material, and in particular solid metallic lithium, is removed from each side edge of the assembly.

[0177] Then, the method according to B) of the method according to the second subject of the invention comprises a phase of extracting the metallic lithium from the cells of the assembly. The extraction phase comprises a step of positioning the assembly in an orientation in which the first edge from which the negative electrodes protrude is at a lower level than the second edge from which the positive electrodes and / or the collectors protrude. In particular, the step positions the assembly in a vertical orientation, i.e. parallel to the gravity vector, with the first edge from which the negative electrodes protrude downwards. Preferably, but in no way limiting, the assembly is maintained in this orientation throughout the extraction phase.

[0178] The extraction phase further comprises a step of heating the assembly to a treatment temperature greater than or equal to the melting temperature of the solid metallic lithium present in the assembly, for example 180.5°C. This temperature will cause the solid metallic lithium to melt and be extracted from each cell by natural flow under the effect of gravity. Preferably, but in no way limitingly, the assembly is maintained at this temperature throughout the extraction phase. Advantageously, the heating step is carried out in a closed enclosure filled with inert gas.

[0179] The extraction phase may further comprise an optional step of compressing the assembly in order to expel the molten lithium from each cell of the assembly. The compression may be carried out continuously during all, or part, of the extraction phase. Alternatively, the compression step may be repeated discretely several times during the extraction phase. Preferably, the compression step applies the compression progressively, or by sweeping, over the surface of the battery, starting with the second edge from which the positive electrodes protrude and moving towards the first edge from which the negative electrodes protrude.

[0180] The method comprises a step of cutting the electrical connection between the positive electrodes / current collectors of at least two, and in particular of all, cells of the assembly. Such a cutting step makes it possible to cut the electrical connection between the positive electrodes of the cells of the assembly, which makes it possible to reduce the reactivity of the assembly. Thus, the risks of fire of the assembly during the extraction phase are reduced, so that the recovery of solid metallic lithium can be carried out in a safer and less risky manner.

[0181] In the example shown, the step of cutting the electrical connections is carried out before the extraction phase. Alternatively, the cutting step can be performed during the extraction phase, before, during or after the positioning step, or before, during or after the heating step.

[0182] Furthermore, the invention is not limited to the embodiments described above, but can be applied to solid or quasi-solid electrolyte assemblies or batteries not comprising a polymer at the cathode. The invention can be applied to any battery having solid metallic lithium and a cathode stable up to the melting point temperature of solid metallic lithium.

[0183] Example 1: Preparation of an electric battery comprising residual solid metallic lithium

[0184] A Lithium Metal Polymer (LMP®) battery module was disassembled and a battery cell was removed and used in this embodiment. Then, a step of extracting Li by melting was carried out according to the method as described in document WO2023 / 036741 A2. The resulting lithium metal was weighed. In this example, 91% of the lithium metal initially present in the cell was extracted. Residual solid lithium metal remains trapped in the battery cell.

[0185] Example 2: extraction of residual lithium according to a process in accordance with the invention

[0186] An all-solid-state lithium battery type electrical storage cell comprising residual lithium (approximately 10% by mass relative to the total mass of lithium present in the initial battery) as prepared in Example 1 was immersed in a soaking tank comprising water (as an aqueous composition), so as to cover said battery with water (approximately 18 L of water). After approximately 12 hours of immersion in the aqueous composition (water), the dissolution of the metallic lithium in the water is complete [step i)].

[0187] The tank water (soaking water or aqueous composition) was analyzed by inductively coupled plasma-atomic emission spectrometry (ICP-AES) and inductively coupled plasma spectrometry (ICP-MS) to measure the lithium concentration. The results obtained show that the all of the residual U was dissolved and recovered in the aqueous composition.

[0188] Step i) also leads to delamination of the electrolyte, positive electrode and current collector films. These solids are removed from the tank [step ii)] and rinsed with approximately 2 L of water above the tank [step ii')].

[0189] Then, approximately 2.25 g of phosphoric acid (H3PO4 85%, Sigma Aldrich) were added with mechanical stirring to approximately 1 L of the aqueous composition as prepared above comprising the residual lithium and previously brought to 60°C [step iii)]. After 2 hours of reaction, the aqueous composition is filtered in order to separate the Li salts from the aqueous composition [step iv)]. The lithium salts obtained are then dried at 100°C for 3 hours [step vi)]. A white powder is thus obtained.

[0190] Example 3: extraction of residual lithium according to a process in accordance with the invention

[0191] Three all-solid-state lithium battery type electrical storage cells comprising residual lithium (approximately 10% by mass relative to the total mass of lithium present in the initial battery) were immersed in a soaking tank comprising water (as an aqueous composition), so as to cover said battery with water (approximately 37 L of water). After approximately 20 hours of immersion in water, the dissolution of the metallic lithium in the water is complete [step i)].

[0192] The aqueous composition was analyzed by inductively coupled plasma-atomic emission spectrometry (ICP-AES) and inductively coupled plasma spectrometry (ICP-MS) to measure the lithium concentration. The results obtained show that all the residual Li was dissolved and recovered in the aqueous composition. The results also show that the amount of lithium dissolved in the aqueous composition is proportional to the number of cells immersed in the aqueous composition.

[0193] Step i) also leads to delamination of the electrolyte, positive electrode and current collector films. The solids are removed from the tank [step ii)] and rinsed with approximately 3 L of water above the tank [step ii')].

[0194] The resulting aqueous composition is heated at 95°C for 1 h so that the electrolyte or its polymer components become insoluble. The resulting composition is filtered to yield a purified aqueous composition [step d)].

[0195] Then, approximately 9 g of phosphoric acid (H3PO4 85%, Sigma Aldrich) were added with mechanical stirring to approximately 1 L of the aqueous composition as prepared above comprising the residual lithium and previously brought to 60°C [step iii)]. After 2 hours of reaction, the aqueous composition is filtered in order to separate the Li salts from the aqueous composition [step iv)]. The lithium salts obtained are then dried at 100°C for 3 hours [step vi)]. A white powder is thus obtained.

[0196] X-ray diffraction (XRD) analyses performed on a sample of the white powder obtained show diffraction peaks corresponding to the U3PO4 phase. No other crystallographic phases could be observed. This result indicates the formation of a product composed mainly of U3PO4.

[0197] The aqueous composition remaining at the end of step iv) has a pH of 7.6. It can therefore be reused in a new process in accordance with the invention as the aqueous composition used in step i).

[0198] The solid residues recovered at the end of step ii') are crushed and analyzed by X-ray diffraction (XRD). The analysis results showed that the solids are composed only of LiFePC which is used as the positive electrode active material, and aluminum which is used as the current collector. This result confirms that the solids separated from the aqueous composition at the end of step ii') are free of metallic lithium or its derivatives, such as lithium hydroxide, LiOH.

[0199] Example 4: extraction of residual lithium according to a process in accordance with the invention

[0200] Example 2 was reproduced using a CO2 stream in the aqueous composition instead of phosphoric acid. Passing the CO2 stream into the aqueous composition leads to the formation of carbonic acid H2CO3 and the precipitation of U2CO3 salts. The recovery efficiency of U2CO3 is improved by heating the solution before CO2 injection due to the lower solubility of U2CO3 in hot water.

[0201] The CO2 flow is maintained until an aqueous composition with a pH of 7 is obtained.

[0202] Example 5: extraction of residual lithium according to a process in accordance with the invention

[0203] Example 2 was reproduced by performing a cutting step [step a)] prior to step i).

[0204] To do this, the cell was cut lengthwise into 5 strips. The 5 strips were then placed in a tank containing approximately 18 L of water (as the aqueous composition) [step i)]. After only 2 hours, the dissolution of the metallic lithium was complete and the films were completely delaminated. The other steps were identical to those described in Example 2.

[0205] Cutting the cell reduces the dissolution time of residual Li.

[0206] Of course, the number of strips is only an indicative example, the dissolution time was improved regardless of the number of strips. It is also possible to cut the cell(s) into other shapes (e.g. into pieces).

[0207] Example 6: Separation of the active material from the current collector

[0208] The solids obtained in Example 3 containing LiFePO4 and aluminum were used: approximately 700 g of the solids were previously ground using a Shini SG-1628N (2.2 kW) knife mill equipped with a 160 x 280 mm cutting chamber with 2 fixed blades and 3 x 4 offset moving blades. Using a calibration grid, the final particle size is between 5 mm and 10 mm. The resulting powder was then passed through an ECS-40 eddy current separator. Two fractions were obtained, one rich in aluminum and the other containing mainly active material, also called Black Mass. The process according to the invention allows the complete recycling of lithium, the active material, the current collector metal as well as the aqueous composition used in step i).

Claims

CLAIMS 1. Method for extracting residual lithium from an assembly of electrical energy storage cell(s) comprising residual solid metallic lithium, said method comprising at least the following steps: i) immersing said assembly in an aqueous composition, ii) separating the solids from the aqueous composition, the solids being active materials of positive electrodes and / or current collectors, iii) adding at least one acid or one of its precursors capable of forming at least one lithium salt insoluble in the aqueous composition, and iv) recovering the lithium salt.

2. Method according to claim 1, characterized in that the aqueous composition comprises at least 90% by mass of water, relative to the total mass of aqueous composition.

3. Method according to claim 1 or 2, characterized in that the acid or one of its precursors is chosen from mineral acids, carboxylic acids, and one of their mixtures.

4. Method according to any one of the preceding claims, characterized in that the acid or one of its precursors is added to the aqueous composition at a rate of at least 10 g / L of aqueous composition.

5. Process according to any one of the preceding claims, characterized in that the aqueous composition at the end of step iii) has a neutral pH.

6. Method according to any one of the preceding claims, characterized in that step ii) comprises or is followed by a step ii') of washing said solids.

7. Method according to any one of the preceding claims, characterized in that it further comprises, before step i), a step a) of cutting the set of cell(s).

8. Method according to any one of the preceding claims, characterized in that it further comprises, before step i), a step b) of grinding the set of cell(s).

9. Method according to any one of the preceding claims, characterized in that it further comprises, before step i), a step c) of oxidation of the residual lithium to lithium oxide.

10. Method according to any one of the preceding claims, characterized in that it further comprises a step d) during which the aqueous composition comprising dissolved lithium is purified.

11. Method for the complete extraction of lithium from a set of electrical energy storage cells comprising solid metallic lithium, said method comprising: A) a first method for extracting lithium from a set of electrical energy storage cells, each cell comprising a negative electrode containing solid metallic lithium, a positive electrode, a solid or quasi-solid electrolyte, and optionally a current collector, said set of cells comprising a first edge from which the negative electrode(s) of said cell(s) protrude and a second edge, opposite said first edge, and from which the positive electrode(s) protrude, said method comprising an extraction phase comprising the following steps: - positioning said assembly in an orientation in which one of said first and second edges is below the other of said first and second edges, and - heating said assembly to a temperature, called treatment temperature, greater than or equal to the melting temperature of said solid metallic lithium, said first extraction method leading to a set of electrical energy storage cell(s) comprising residual solid metallic lithium, and B) a second method of extracting residual lithium as defined in any one of the preceding claims.

12. Method according to claim 11, characterized in that it further comprises a step of cutting the electrical connection between the positive electrodes of at least two, and in particular of all, the cells of said assembly.

13. Unit for extracting residual lithium from a set of electrical energy storage cell(s) comprising residual solid metallic lithium, characterized in that it comprises: - a tank for soaking the entire cell(s) in an aqueous composition; - one or more means for separating solids from the aqueous composition; - a means of adding acid or one of its precursors to the aqueous composition; and - one or more means of solid / liquid separation for the recovery of the lithium salt(s).

14. Integral installation for extracting lithium from a set of electrical energy storage cell(s), each cell comprising a positive electrode, a negative electrode comprising solid metallic lithium, a solid or quasi-solid electrolyte, and possibly a current collector, said assembly comprising a first edge from which the negative electrode(s) of said cell(s) protrude and a second edge, opposite said first edge, and from which the positive electrode(s) protrude, said extraction installation comprising: * a lithium extraction unit leading to a set of cell(s) comprising residual solid metallic lithium, said lithium extraction unit containing: - means for positioning said assembly in an orientation in which one of said first and second edges is below the other of said first and second edges; and - a heating means configured to heat said assembly to a temperature, called treatment temperature, greater than or equal to the melting temperature of said solid metallic lithium, and * a residual lithium extraction unit as defined in claim 13.

Images