Safe method for extracting lithium from an electric battery containing lithium.

Abstract

The invention relates to a method (300) for extracting lithium from an electric battery comprising metallic lithium, said method (300) comprising a lithium extraction phase (302), said extraction phase (302) comprising the following steps carried out, at least in part, within a chamber: heating (304) of said battery to a temperature, referred to as the processing temperature, greater than or equal to the melting point of metallic lithium; compression (306) of said battery to remove the molten lithium from the battery; characterized in that the heating step (304) is carried out by circulating, within said chamber, a hot stream, referred to as the heating stream, in contact with said battery. It also relates to a system implementing such a method. Figure: Fig. 3

Description

Title of the invention: Safe method for extracting lithium from an electric battery containing lithium.

[0001] The present invention relates to a method for the safe extraction of lithium from an electric battery comprising lithium, in particular metallic lithium. It further relates to a system implementing such a method.

[0002] The field of the invention is the field of recycling lithium found in electric batteries comprising lithium, in particular metallic lithium, and in particular metallic lithium-based batteries, and even more particularly Lithium-Metal-Polymer batteries. State of the art

[0003] Lithium-based batteries, particularly metallic lithium batteries, are known, such as Lithium-Metal-Polymer (LMP) batteries (LMP®), which comprise a metallic lithium anode, a cathode consisting of a polymer-based layer and active material, an aluminum current collector, and, between the anode and cathode, an electrolyte comprising a mixture of polymer and lithium salts. These batteries are increasingly used, for example, in electric vehicles or in power stations. Thus, the number of lithium-based batteries has been steadily increasing for several years, and the example of LMP batteries, given purely as an illustration, is by no means limiting.

[0004] The lifespan of lithium-containing batteries is not infinite. Even at the end of its life, such a battery still contains valuable lithium that can be reused and whose value is significant, not to mention the regulatory obligation to recover said lithium.

[0005] For example, a process for recovering metallic lithium from a battery is known, described in the international application published under number WO2020 / 161339 AL. This process is very efficient and allows for the safe recovery of almost all of the lithium present in a battery cell by heating, to a temperature greater than or equal to the melting temperature of metallic Li, and then compression.

[0006] However, the inventors have observed that heating and / or compressing a lithium battery results in the emission of a significant amount of volatile organic compounds, VOCs. These VOCs can cause a fire, particularly at the battery processing temperatures. This can make the recovery of metallic lithium and the industrial-scale recycling of these end-of-life batteries challenging.

[0007] One object of the present invention is to remedy this drawback.

[0008] Another object of the invention is to provide a safer and less restrictive method for recovering lithium from a battery on an industrial scale. Description of the invention

[0009] The invention makes it possible to achieve at least one of these objectives by a process for extracting lithium from an electric battery comprising metallic lithium, said process comprising a lithium extraction phase, said extraction phase comprising the following steps carried out, at least in part, in an enclosure: - heating said battery to a temperature, called processing temperature, greater than or equal to the melting point of metallic lithium; - compression of said battery to evacuate the molten lithium out of the battery; characterized in that the heating stage is carried out by circulation, in said enclosure, of a hot flow, called heating flow, coming into contact with said battery.

[0010] The inventors of the present invention have observed that the lithium extraction phase generates VOCs released by the battery. These VOCs are flammable and present a risk of ignition or fire during the lithium extraction phase, which can compromise the industrial recycling of these batteries.

[0011] To remedy this situation, the invention proposes heating the battery by circulating a heating flow within the enclosure. This heating flow heats the battery. Furthermore, the heating flow circulating within the enclosure removes some or all of the VOCs from the enclosure. Thus, the invention makes it possible to remove some or all of the VOCs released by the battery from the enclosure during the heating and / or compression stages. Consequently, the invention allows for a safer extraction of lithium from a lithium battery.

[0012] The processing temperature is greater than or equal to the melting point of lithium, and in particular of metallic lithium.

[0013] In particular, the processing temperature is greater than or equal to 185°C.

[0014] According to one embodiment, the treatment temperature may be less than or equal to a maximum temperature, for example 300°C.

[0015] The heating flow can be a gaseous flow.

[0016] The heating flow can be an air flow, in particular dry air.

[0017] The heating flux can be a neutral gas flux, such as argon (Ar).

[0018] The heating flux may be at a temperature greater than or equal to the processing temperature. For example, the heating flux may be at a temperature of 185°C, or 200°C.

[0019] According to embodiments, the temperature of the heating flow can be variable and in particular adjustable.

[0020] The battery may comprise a single cell, or several cells.

[0021] Generally, the battery may include a first border from which the negative electrodes of the cells protrude and a second border, opposite said first border, from which the positive electrodes of the cells protrude.

[0022] According to the invention, part or all of the extraction phase can be carried out in one or more enclosures.

[0023] According to embodiments, the heating step and the compression step can be carried out in the same common enclosure.

[0024] In this case, the heating flow is circulated in said single enclosure.

[0025] In this case, the heating flow can only be put into circulation when the heating stage. Alternatively, the heating flow can be circulated during the heating stage, but also during part or all of the compression stage, to remove the VOCs released by the battery during said compression stage.

[0026] According to embodiments, the heating step can be carried out in an enclosure, called a heating enclosure.

[0027] The compression step can be carried out in an enclosure, called a compression enclosure.

[0028] In particular, the heating stage and the compression stage can be carried out in separate enclosures.

[0029] The heating and compression chambers can be glued together. Alternatively, the heating and compression chambers can be spaced apart.

[0030] According to some embodiments, the heating chamber can be used to heat several batteries simultaneously. Indeed, the heating stage is longer than the compression stage, making it possible to heat several batteries at the same time.

[0031] According to embodiments, the process according to the invention may include a circulation of a flow, called evacuation flow, during the compression step, in particular to evacuate at least part of the volatile organic compounds, VOCs, released by the battery during said compression step.

[0032] Thus, the VOCs released by the battery during the compression stage are vented outside the enclosure. The inventors noted that the battery releases a quantity A significant amount of VOCs is released during the compression stage. Specifically, during compression, the battery releases a greater quantity of VOCs than during the heating stage. Therefore, removing VOCs from the chamber during compression further enhances the safety of lithium extraction from a lithium battery.

[0033] According to some embodiments, the exhaust flow may be part or all of the heating flow. In this case, the heating flow used for heating the coil may be used as the exhaust flow during the compression stage. In this case: - the heating and compression stages can be carried out in the same chamber; or - the heating and compression stages can be carried out in separate chambers.

[0034] Depending on the embodiment, the exhaust flow may be different from the heating flow. In this case, a flow other than the heating flow may be used for the exhaust of VOCs during the compression step. In this case: - the heating and compression stages can be carried out in the same chamber; or - the heating and compression stages can be carried out in separate chambers.

[0035] The exhaust flow can be a gaseous flow.

[0036] The exhaust flow can be an air flow, in particular dry air.

[0037] The exhaust flow can be a neutral gas flow, such as argon (Ar).

[0038] The exhaust flow can be at ambient temperature.

[0039] Preferably, the exhaust flow can be at a temperature higher than the ambient temperature so as not to cool the battery.

[0040] According to embodiments, the temperature of the evacuation flow can be variable and in particular adjustable.

[0041] According to a non-limiting example of an embodiment, the evacuation flow can be at a temperature of around 60° or 65°C.

[0042] According to a non-limiting example of an embodiment, the evacuation flow may be at the processing temperature so as not to cool the battery during its compression.

[0043] According to embodiments, the process according to the invention may further include a measurement of the concentration of at least one volatile organic compound in the enclosure, during the extraction phase.

[0044] The measurement can be carried out during the heating stage.

[0045] Alternatively, or in addition, the measurement can be carried out during the step of compression.

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[0058] The measurement can be carried out in the common area, if necessary. The measurement can be carried out in the heating chamber, and / or in the compression chamber, as appropriate. The measured concentration can be used for: - adjust the heating flow rate, and / or - where applicable, the flow rate of the evacuation flow. Alternatively, or in addition, the measured concentration can be used for: - to trigger or stop the flow of the evacuation stream; and / or - if necessary, start or stop the flow of the evacuation; used during the compression stage. Alternatively, or in addition, the measured concentration can be used to trigger an alert, or an emergency stop of the heating stage, and / or the compression stage, more generally of the extraction phase. Depending on embodiments, the method according to the invention may further include an adjustment: - the flow rate of the heating stream, and / or - where applicable, the flow rate of the evacuation flow. This flow rate adjustment can be made based on various parameters, such as the temperature in the enclosure, the number of batteries in the enclosure, etc. Following an example implementation, this flow rate adjustment can be made based on a measured VOC concentration, as described above. Depending on embodiments, the process according to the invention may further include a temperature adjustment: - of the heating flow, and / or - where applicable, of the evacuation flow. This temperature adjustment can be made based on various parameters, such as the temperature inside the enclosure, the number of batteries in the enclosure, etc. Following an example implementation, this temperature adjustment can be made based on a VOC concentration measured in the enclosure, as described above. According to embodiments, the process according to the invention may include recovering at least part of the heat from at least one outgoing flow of the enclosure to heat at least one incoming flow into said enclosure, or into another of the enclosures used during the extraction phase. As described above, the invention uses a heating flow to heat the battery during the heating stage.

[0059] Furthermore, according to an optional feature, the invention can use an exhaust flow during the compression step to evacuate the VOCs released by the battery during said compression step.

[0060] Thus, the heating flow, and respectively the exhaust flow, exiting the enclosure each contain waste heat that can be recovered in the process according to the invention, for example, to preheat the heating flow and / or the exhaust flow before its introduction into the enclosure. The invention may thus comprise a heat exchange between: - an outgoing flow from the enclosure, namely the common enclosure, the heating enclosure, or the compression enclosure; and - an incoming flow into said enclosure or into another enclosure used during the extraction phase, namely the common enclosure, the heating enclosure or the compression enclosure; to heat said incoming flow.

[0061] This makes it possible to reduce the energy consumed during the overall process, and to reduce the energy and environmental footprint of lithium extraction.

[0062] In addition, the heating flow, respectively the exhaust flow, exiting the enclosure is loaded with VOCs.

[0063] The invention may include the oxidation, and / or combustion, and more generally the recovery, of at least a portion of the VOCs present in an outgoing stream from the enclosure, namely the common enclosure, the heating enclosure, or the compression enclosure. This recovery makes it possible, on the one hand, to eliminate said VOCs so that they no longer present a fire risk. On the other hand, this exothermic combustion makes it possible to generate heat that can be used to heat an incoming stream from the enclosure, namely the common enclosure, the heating enclosure, or the compression enclosure.

[0064] This reduces the energy consumed during the overall process, and decreases the energy and environmental footprint of lithium extraction, while further securing lithium extraction.

[0065] According to embodiments, the process according to the invention may include reusing at least part of a flow exiting an enclosure, to reuse it as a flow entering said enclosure, or at least one of the enclosures, used during the extraction phase.

[0066] In this case, the process according to the invention may further include the removal of at least a portion of the VOCs in said outgoing stream. According to one embodiment, the removal of the VOCs may be carried out, for example, by combustion. According to another example, the removal of the VOCs may be carried out, for example, by trapping, or filtering, of said VOCs by a carbon filter / column through which said outgoing flow passes.

[0067] The compression step forces the molten lithium to evacuate from the battery.

[0068] The compression step can be carried out continuously throughout the extraction phase. In this case, the battery is subjected to compression, in part or in full, throughout the extraction phase, and in particular during the heating step.

[0069] Alternatively, the compression step can be carried out after the heating step, i.e. when the heating step is completed.

[0070] The compression step can apply compression to the surface of the battery by sweeping the surface of said battery from the second edge where the positive electrodes of said battery protrude, towards the first edge where the negative electrodes of said battery protrude. Thus, the molten lithium is gradually brought / guided towards the first edge where the negative electrodes protrude, which increases the amount of lithium recovered and reduces the risk of contact (or short circuit) between the lithium and the positive electrodes.

[0071] For example, the compression step can be carried out by passing the battery between two rollers, in particular two heated rollers.

[0072] Following another example, the compression step can be carried out by a compression roller, in particular heated, compressing the battery against a support surface, in particular heated.

[0073] Compression can be applied by successive passes, each pass sweeping the surface of the battery starting from the second edge towards the first edge.

[0074] The space between the compression rollers, or between the compression roller and the bearing surface, can correspond to the thickness of the battery minus the thickness of the metallic lithium layers. This allows compression to be applied as long as metallic lithium remains in the battery.

[0075] The space between the two compression rollers, respectively between the compression roller and the bearing surface, can be reduced with successive passes, so as to always apply compression to the battery.

[0076] 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 and a few tens of mm per second.

[0077] According to embodiments, the process according to the invention may further include, before the extraction phase, an electrical charging step of the battery, said extraction phase being applied to said charged battery.

[0078] Electrically charging the battery and performing the extraction phase on the electrically charged battery increases the lithium extraction yield. Indeed, the electrical charging of a cell allows lithium ions to move towards the negative electrode, thus increasing the amount of lithium that can be recovered.

[0079] In the case where the battery comprises several cells, the method according to the invention may further include a step of breaking the electrical connection between the positive electrodes of at least two, and in particular of all, the cells of said battery. Thus, the electrical connection between the cells is broken, which reduces the risk of fire or ignition.

[0080] According to one embodiment, the cutting step can perform a cutting of connecting wires between the positive electrodes along a cutting line located at the level, and in particular at the limit, of the second border, on the side of said electrical connecting wires.

[0081] This embodiment makes it possible to retain, or not remove, solid metallic lithium from the battery, when the electrical connections are cut off, which makes it possible to improve the lithium recovery efficiency.

[0082] In this embodiment, the cutting of the connecting wires must be sufficiently close to the second edge, so that after the cutting, there is no longer any contact between the different positive electrodes.

[0083] According to another embodiment, the cutting step can perform a cutting of the cells along a cutting line located at the level, and in particular at the limit, of the second border, on the side of the cells.

[0084] In this embodiment, in order to reduce the amount of lithium lost, the cut must be in the immediate vicinity of the second edge.

[0085] For example, the cut can be made at a distance "d" from the second edge less than or equal to 2mm, or less than or equal to 1% of the cell dimension between the first and second edges of the battery.

[0086] The cutting step can be carried out by cutting. In this case, the battery can be inserted into a cutter of suitable size and power.

[0087] The switching step can be carried out before the heating step.

[0088] In addition, the method according to the invention may include, before the extraction phase, a step of removing at least one electrical connector from the battery, also called a "crimp" in English.

[0089] This makes battery processing easier.

[0090] For example, the step of removing at least one electrical connector from the battery may include a step of removing at least one negative connector, also called "crimp anode". This facilitates / improves the flow of molten lithium out of the cell.

[0091] For example, the step of removing at least one electrical connector from the battery may include a step of removing at least one positive connector, also called "crimp cathode".

[0092] In addition, the process according to the invention may include, before the extraction phase, a step of removing excess material at the level of at least one, and particularly each, edge of the battery.

[0093] According to embodiments, the method according to the invention may further include a step of positioning the battery in an orientation in which the first border is below the second border.

[0094] Such an orientation of the battery, and therefore of each cell of the battery, 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 an electrical short circuit or an electric arc, such a short circuit being able to cause a fire.

[0095] According to a preferred embodiment of this first version, the positioning step can achieve a vertical positioning of the battery, in which the first edge is at the bottom.

[0096] Thus, the flow of molten lithium out of each cell, by gravity, is improved.

[0097] Furthermore, the risk of contact between the molten lithium and the positive electrode(s) is reduced, or even eliminated.

[0098] According to another aspect of the same invention, a lithium extraction system is proposed for an electric battery comprising lithium, said system comprising: - at least one heating means, in an enclosure, configured to heat said battery to a temperature, said processing temperature, greater than or equal to the melting temperature of said metallic lithium; - at least one means of compressing said battery to evacuate the molten lithium out of the battery; characterized in that the heating means includes a first means of circulation, in said enclosure, of a hot flow, said heating flow, coming into contact with said battery.

[0099] Generally, the system according to the invention may include, in terms of technical means, or hardware configuration and / or software configuration, at least one, or any combination of at least two, of the optional features described above with reference to the method according to the invention.

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[0110] [YES] The first means of circulation may include a means of blowing and / or a means of suction. According to embodiments, the system according to the invention may include a common enclosure in which the heating and compression of the battery are carried out. According to embodiments, the system according to the invention may include a separate enclosure, called a heating enclosure, in which the heating of the battery is carried out. According to embodiments, the system according to the invention may include a separate enclosure, called a compression enclosure, in which the compression of the battery is carried out. Depending on the embodiment, the heating chamber can be used to heat several batteries at once. According to embodiments, the system according to the invention may include a heating chamber for several compression chambers. In this case, at least two batteries heated in the same heating chamber can be compressed in different compression chambers. According to embodiments, the system according to the invention may include a second means of circulating a flow, called evacuation flow, during the compression of the battery, in particular to evacuate at least part of the VOCs released by the battery. This second circulation method can correspond, at least in part, to the first circulation method. In this case, the exhaust flow can be the heating flow. Also in this case, heating and compression of the coil can be achieved: - within a common enclosure, or - in separate enclosures. This second circulation method may be, at least in part, different from the first circulation method. In this case, the exhaust flow is not the heating flow. Also in this case, heating and compression of the coil can be achieved: - within a common enclosure, or - in separate enclosures. The second means of circulation may include a means of blowing and / or a means of suction. Depending on the embodiment, the first means of circulation may be adjustable / controllable to adjust: - the flow rate, and / or

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[0122] - the temperature; of the heating flow. The adjustment can be made based on a measured temperature, or a measured concentration of VOCs. Depending on the embodiment, the second means of circulation may be adjustable / controllable to adjust: - the flow rate, and / or - the temperature; of the evacuation flow. The adjustment can be made based on a measured temperature, or a measured concentration of VOCs. According to embodiments, the system according to the invention may include at least one gas sensor for measuring the concentration of at least one volatile organic compound, VOC. When heating and compression of the battery are carried out in a common enclosure, at least one measuring means may be disposed in said common enclosure, or at least equip said common enclosure. When the heating and compression of the battery are carried out in separate enclosures, namely a heating enclosure and a compression enclosure, then the system according to the invention may include - at least one sensor fitted to the heating chamber, and / or - at least one sensor fitted to the compression chamber. The system according to the invention may further include at least one means of recovering at least a portion of the energy from at least one outgoing flow from an enclosure of the system according to the invention, to heat at least one incoming flow into said enclosure, or into at least one enclosure, of the system according to the invention. Such a recovery method may include a heat exchanger to recover some of the waste heat from the outgoing stream. Such a recovery method may include a means of combustion, or oxidation, and more generally of valorization, to burn the VOCs present in the outgoing stream and thus generate usable heat to heat the incoming stream. The system according to the invention may further include at least one means for recirculating at least a part of a flow exiting an enclosure of the system according to the invention, for reuse as a flow entering said enclosure, or at least one of the enclosures, of the system according to the invention. In this case, the system according to the invention may further include at least one means for removing VOCs from said outgoing stream. According to one embodiment, the removal of VOCs may be achieved, for example, by combustion. Following another example, the elimination of VOCs can be achieved for example by trapping, or by filtering, said VOCs by a carbon filter / column through which said outgoing flow passes.

[0123] The compression means can be in any form.

[0124] According to embodiments, the compression means may include at least one roller, in particular a heated one.

[0125] In particular, the compression means may comprise a single roller, in particular a heated roller, compressing the battery against a support surface, in particular a heated surface. The support surface may be heated to accelerate the temperature rise of the battery.

[0126] Alternatively, the compression means may comprise two rollers, in particular heated rollers, between which the battery is passed.

[0127] In general, the compression means can be configured to apply continuous compression throughout the extraction phase.

[0128] Alternatively, the compression means can be configured to apply compression discretely over time, once or several times, during the extraction phase. In this case, the extraction phase includes moments when the battery is not subjected to compression.

[0129] Advantageously, the compression means can be configured to apply compression, of constant or variable value, progressively or by sweeping across the surface of the battery, from the second edge to the first edge. Thus, the molten lithium is gradually brought / guided towards the first edge, which is in the lower position, thereby increasing the amount of lithium recovered and reducing the risk of contact between the lithium and the positive electrodes.

[0130] When using one or two compression rollers, compression can be applied to the battery in successive passes. Each pass applies sweeping compression to the battery surface, from the second edge to the first edge. At the end of each pass, compression can be stopped by moving the rollers apart or by moving the roller away from the support surface, returning to the second edge to begin a new pass.

[0131] The distance between the rollers, respectively between the compression roller and the bearing surface, can be decreased as the passes progress, and in particular between two successive passes.

[0132] According to embodiments, the system according to the invention may further include a means for breaking the electrical connection between the positive electrodes of at least two, and in particular of all the cells of said battery.

[0133] For example, the cutting means may include a guillotine. Description of the figures and methods of implementation

[0134] Other advantages and features will become apparent upon examination of the detailed description of non-limiting embodiments and the accompanying drawings, in which: - [Fig.1] is a schematic representation of a non-limiting example embodiment of a cell within the meaning of the present invention; - [Fig.2] is a schematic representation of a non-limiting example of a battery within the meaning of the present invention; - the [Fig.3]-5 are schematic representations of non-limiting examples of embodiments of a process according to the invention; - FIGURES 6a-6c are schematic representations of a non-limiting example embodiment of a system according to the present invention; - Figures 7a-7c are schematic representations of another, non-limiting embodiment of a system according to the present invention; and Figures 8a-8c are schematic representations of another, non-limiting embodiment of a system according to the present invention.

[0135] It is understood that the embodiments described below are in no way limiting. In particular, variants of the invention may be conceived comprising only a selection of features described below, isolated from the other features described, if this selection of features is sufficient to confer a technical advantage or to differentiate the invention from the prior art. This selection includes at least one preferably functional feature without structural details, or with only a portion of the structural details if this portion is sufficient solely to confer a technical advantage or to differentiate the invention from the prior art.

[0136] In the figures, the elements common to several figures retain the same reference.

[0137] Fig. 1 is a schematic representation of a non-limiting example embodiment of a cell within the meaning of the present invention.

[0138] The cell 100, shown in [Fig.1], includes a negative electrode 102. According to a non-limiting embodiment, the negative electrode 102 is formed by, or comprises, a layer of solid metallic lithium.

[0139] The cell 100 further comprises a positive electrode 104. According to a non-limiting embodiment, the positive electrode 104 is formed by a polymer-based layer and active material.

[0140] A layer 106 of electrolyte is disposed between the negative electrode 102 and the positive electrode 104. According to a non-limiting embodiment, this solid electrolyte layer 106 may, for example, comprise lithium salts.

[0141] The cell 100 further includes a current collector 108, on the side of the positive electrode 104. According to a non-limiting embodiment, the current collector 108 can be made of aluminum.

[0142] According to a non-limiting architecture, in the example of [Fig.1], the negative electrode 102 of the cell 100 protrudes from the other elements of the cell 100 on the side of a first border 110 of the cell 100. Also according to the non-limiting architecture of [Fig.1], the positive electrode 104, and / or the collector 108, of the cell 100 protrudes from the other elements of the cell 100 on the side of a second border 112, opposite to the first border 110.

[0143] Of course, cell 100 shown in [Fig. 1] is a very simplified embodiment, given by way of non-limiting illustration. The cell within the meaning of the present invention may comprise a multitude or a succession of several anode / electrolyte / cathode layers, or at least one other layer than those indicated, or at least one layer whose composition differs from the composition given here by way of non-limiting example.

[0144] Fig. 2 is a schematic representation of a non-limiting example embodiment of a battery within the meaning of the present invention.

[0145] A battery according to the present invention may comprise one or more cells, and in particular one or more cells 100 of the [Fig.1].

[0146] In the example shown in [Fig.2], the battery 200 comprises n cells 100r 100n, with n>l.

[0147] All 100r100n cells can be identical.

[0148] The cells 100i-100n are assembled along a direction 202 perpendicular to the plane of each cell 100;.

[0149] Each cell 100;, with l <i<n, peut être identique à la cellule 100 de la [Fig.l].

[0150] Of course, the battery 200 may include other components than those shown in [Fig.2] which gives a simplified schematic representation of a battery.

[0151] In the following, and without loss of generality, the battery is considered to comprise several cells assembled along an assembly direction.

[0152] Fig. 3 is a schematic representation of a non-limiting example of an embodiment of a method according to the present invention.

[0153] The process 300 of [Fig.3] can be used to recover lithium from a battery comprising lithium, in particular metallic lithium, and even more particularly from battery 200 of [Fig.2].

[0154] The process 300 includes a phase 302 of lithium extraction from the battery by heating and compression of the battery.

[0155] To do this, the extraction phase 302 includes a step 304 of heating the battery.

[0156] In the embodiment shown in [Fig. 3], the heating of the battery is carried out in a chamber, referred to as a heating chamber. More specifically, the battery is placed in a closed heating chamber in which a heating gas flow is circulated.

[0157] In practice, a hot heating gas flow is introduced into the chamber, circulates within the chamber, and comes into contact with the battery to heat it, then exits the chamber. This circulation of the heating gas flow within the heating chamber is carried out for a sufficient duration, for example, on the order of 1 hour 20 minutes, to bring the battery to a treatment temperature of 185°C or higher. At this temperature, the metallic lithium in the battery begins to melt and is ready to flow out of the battery. Of course, the duration indicated above is purely indicative and in no way limiting.

[0158] The inventors of the present invention have observed that the heating step 304 causes the release of VOCs from the battery. These VOCs then accumulate in the enclosure where the battery heating takes place and constitute a potential source of fire.

[0159] The invention proposes to address this problem by achieving, during the heating stage, the evacuation of VOCs from the enclosure using the heating flow circulating within the enclosure. Indeed, heating the coil by circulating a heating flow within the enclosure also allows for the evacuation of the VOCs released by said coil during said heating stage, from said enclosure, by said heating flow circulating within the enclosure. In other words, the heating gas flow, in addition to heating the coil, also ventilates the interior of the enclosure and carries the VOCs out of the enclosure during the heating stage.

[0160] The exhaust gas stream may be at a temperature greater than or equal to the processing temperature, in particular 185°C. The heating gas stream may consist of air, in particular dry air, or of an inert gas, such as argon.

[0161] The extraction phase 302 includes a step 306 of compressing the heated battery to force the molten metallic lithium, contained in the heated battery, to evacuate out of said battery.

[0162] In the embodiment shown in [Fig. 3], the battery compression is carried out in a chamber, referred to as a compression chamber. More specifically, the battery, heated to at least 185°C, is placed in a compression chamber comprising means compression. It is then compressed perpendicularly to the plane of the cells to force the molten lithium out of the battery. The molten lithium is collected, for example in a tray or container, positioned under the battery.

[0163] The battery compression can be achieved in various ways. According to a non-limiting embodiment, the heated battery is passed between two rollers, particularly heated ones, which apply compression to the surface of the battery by sweeping across its surface, for example, from the second edge 112 to the first edge 110, from which the negative electrodes 102 of the battery cells protrude. Thus, the molten lithium is gradually brought / guided towards the first edge and then exits the battery through the first edge.

[0164] The inventors of the present invention have observed that the compression step 306 causes the release of VOCs from the battery. These VOCs then accumulate in the enclosure and constitute a potential source of fire.

[0165] In the non-limiting example of [Fig.3], the extraction phase 302 further includes an optional step 310 for removing VOCs during the compression step 306. This removal of VOCs can be carried out during the entire duration of the compression step, or only part of the compression step 306, or just after the compression step.

[0166] Step 310 removes VOCs from the enclosure by circulating an exhaust gas flow within said enclosure. This exhaust gas flow thus ventilates the interior of the enclosure and carries the VOCs out of the enclosure.

[0167] The exhaust gas stream can be the heating gas stream used during heating step 304.

[0168] Alternatively, the exhaust gas stream may be a different stream than the heating gas stream. In this case, the exhaust gas stream may be at ambient temperature. Alternatively, the exhaust gas stream may be at a temperature higher than ambient temperature, for example, 60°C. The exhaust gas stream may consist of air, in particular dry air, or of an inert gas, such as argon.

[0169] Without limitation, the heating and compression chambers may be separate: in this case, these chambers may be in contact with each other, or at a distance from each other. Alternatively, the heating and compression chambers may be a single, common chamber.

[0170] The invention is not limited to any particular enclosure architecture.

[0171] According to a feature not shown, the extraction phase 302 may include a measurement of the VOC concentration in the heating chamber. By

[0172]

[0173]

[0174]

[0175]

[0176]

[0177]

[0178]

[0179]

[0180] For example, this measurement can be performed at a fixed frequency or continuously. The measured concentration can be used for: - to start or stop heating step 304, - adjust the flow rate, and / or temperature, of the heating flow, and / or - an emergency stop. Depending on a feature not shown, extraction phase 302 may include a measurement of the VOC concentration in the compression chamber. For example, this measurement may be performed at a fixed frequency or continuously. The measured concentration may be used for: - to start or stop compression step 306, - adjust the flow rate, and / or temperature, of the evacuation flow, and / or - an emergency stop. Figure 4 is a schematic representation of another non-limiting example of an embodiment of a method according to the present invention. The 400 process of [Fig.4] can be used to recover lithium from a battery containing lithium, in particular metallic lithium, and even more particularly from battery 200 of [Fig.2]. Process 400 of [Fig.4] includes a lithium extraction phase 402 comprising all the steps of extraction phase 302 of process 300 of [Fig.3], except step 310 of VOC removal during the compression step. Figure 5 is a schematic representation of another non-limiting example of an embodiment of a method according to the present invention. The 500 process of [Fig.5] can be used to recover lithium from a battery containing lithium, in particular metallic lithium, and even more particularly from battery 200 of [Fig.2]. Process 500 includes an optional step 502, which performs electrical recharging of the battery. The battery can be partially or fully charged. Electrically charging the battery increases the amount of lithium available for extraction because the recharging process causes lithium ions to migrate from the negative electrode of each battery cell. Process 500 includes an optional step 504 of breaking the electrical connection between the positive electrodes of at least two, and in particular all, of the cells of said battery. Thus, the electrical connection between the cells is broken, which reduces the risk of fire or ignition. Process 500 includes an optional step 506 for removing electrical connectors, and in particular current concentrators, also known as "crimps." Specifically, step 506 removes the anode crimps for Facilitating the flow of molten lithium from each cell, and optionally the removal of cathode crimps. Optionally, step 506 can also remove excess material, particularly solid metallic lithium, from each lateral edge of the battery.

[0181] The process 500 further includes an optional but highly advantageous step 508 for positioning the battery in an orientation in which the first edge, 110 in the example of battery 200, from which the negative electrodes protrude, is at a lower level than the second edge, 112 in the example of battery 200, from which the positive electrodes and collectors protrude. In particular, step 508 positions the battery in a vertical orientation, that is, parallel to the gravity vector, with the first edge at the bottom. Preferably, but not exclusively, the battery is maintained in this orientation throughout the extraction phase.

[0182] Next, the process 500 includes an extraction phase 510, such as, for example, the extraction phase 302 or 402 described with reference to FIGURES 3 and 4.

[0183] FIGURES 6a-6c are schematic representations of a non-limiting example embodiment of a system according to the present invention.

[0184] The 600 system of FIGURES 6a-6c can be used to extract and recover lithium from a battery comprising lithium, in particular metallic lithium, and even more particularly from battery 200 of [Fig.2].

[0185] System 600 can be used to implement a process according to the invention, for example any one of the processes 300, 400 or 500.

[0186] The system 600 includes a heating chamber 602 in which the battery 200 is heated, a compression chamber 604 in which the battery 200 is compressed, and optionally a cooling chamber 606 for the battery 200 after lithium extraction.

[0187] In [Fig.6a], battery 200 is located in the heating chamber 602, in [Fig.6b] battery 200 is located in the compression chamber 604 and in [Fig.6c] battery 200 is located in the optional cooling chamber 606.

[0188] During its processing in the system 600, the battery 200 can optionally be placed on a support 608.

[0189] The support 608 allows the battery 200 to be positioned and held in an orientation in which the first edge 110, from which the negative electrodes protrude, is below the level of the second edge 112, from which the positive electrodes protrude. In the example in FIGURE 6, the support 608 holds the battery 200 in a vertical position with the first edge 110 at the bottom and the second edge 112 at the top.

[0190] In addition, the support 608 can be equipped with a receptacle 610 for receiving the molten lithium metal. In particular, the molten lithium metal exiting the battery 200 flows out of said battery 200 and then towards the receptacle 610 under the effect of gravity and is collected in said receptacle 610.

[0191] In embodiments, the support 608 and the receptacle 610 can be formed from a single piece, or a single component.

[0192] The heating chamber 602 is equipped with a first means for circulating a heating flow within the heating chamber 602 to raise the battery 200 to a processing temperature greater than or equal to the melting point of metallic lithium, for example greater than or equal to 185°C. In the example of FIGURES 6a-6c, the first circulation means comprises: - an inlet duct 614i for the heating flow into the heating chamber 602, - an outlet duct 6142 for the heating flow out of the heating chamber 602, and - a means of driving the heating flow 6143, such as for example a fan, a blower, etc. Thus, the heating flow enters the heating chamber 602 through the inlet duct 614i, sweeps through the heating chamber 602, and in particular the battery 200 located in the chamber to heat said battery 200, and exits through the outlet duct 6142 carrying some or all of the VOCs.

[0193] The heating flux may be a dry air flux or an inert gas flux, such as argon (Ar). The heating flux may be at a temperature higher than the processing temperature, for example greater than or equal to 185°C.

[0194] Optionally, the heating chamber 602 can be equipped with a sensor 616 to measure the VOC concentration within said chamber 602. This sensor 616 can be configured to measure the VOC concentration continuously or at a predetermined frequency. The concentration measured by the sensor 616 can be used to start, stop, or adjust the circulation of the heating flow, either directly or through a control module (not shown). In this case, the drive means 6143 can be controllable / adjustable. The concentration measured by the sensor 616 can be used to adjust the temperature of the heating flow. The concentration measured by the sensor 616 can be used to trigger an emergency shutdown of the system 600, and in particular of the heating system.

[0195] Of course, the heating enclosure 602 may include other component(s) than those described here.

[0196] In the compression chamber 604, the battery 200 is held by the support 608 as described above.

[0197] The compression chamber 604 is equipped with a battery compression means for forcing the molten lithium metal out of said battery 200. In the example shown in FIGURES 6a-6c, the compression means comprises a pair of rollers 622, in particular heated, facing each other. The battery 200 is positioned between the rollers 622 in a vertical orientation in which the first edge 110 is below the second edge 112. The rollers 622 apply compression to the battery 200, for example by successive passes, by sweeping the battery 200 from the second edge 112 to the first edge 110. Thus, the molten lithium metal exits the battery 200 through the first edge 110 and flows into the recovery receptacle 610. This example of a compression means is not limiting, and other variations may be used.

[0198] Optionally, the compression chamber 604 is equipped with a means for venting VOCs from said chamber 604. In the example of FIGURES 6a-6c, said venting means includes a second means for circulating a vent stream within said compression chamber 604. In particular, the second vent gas stream circulation means includes: - an inlet duct 624i for the exhaust flow into the compression chamber 604, - an outlet conduit 6242 for the exhaust flow from the compression chamber 604, and - a means of driving said evacuation flow, such as for example a fan, a blower, etc. Thus, the exhaust flow enters the compression chamber 604 through the inlet duct 624b, sweeps through the compression chamber 604, and in particular the battery 200 located in the chamber, and exits through the outlet duct 6242 carrying some or all of the VOCs located in the compression chamber 604.

[0199] The exhaust flow can be the heating flow.

[0200] Alternatively, the exhaust flow can be a dry air flow or a neutral gas flow, such as argon (Ar). The exhaust flow can be at ambient temperature or at a temperature higher than ambient temperature, for example around 60°C, or even at the processing temperature so as not to cool the battery 200 during its compression.

[0201] Optionally, the compression chamber 604 can be equipped with a sensor 626 for measuring the concentration of VOCs in said chamber 604. This sensor 626 can be configured to measure the concentration of VOCs continuously, or at a predetermined frequency. The concentration measured by sensor 626 can be used to start, stop, or adjust the circulation of the exhaust gas flow in the compression chamber, either directly or via a control module (not shown). In this case, the drive means 6243 can be controlled / adjustable. The concentration measured by sensor 626 can be used to adjust the temperature of the exhaust flow. The concentration measured by sensor 626 can be used to trigger an emergency shutdown of system 600, and in particular, of the compression unit.

[0202] Of course, the compression chamber 604 may include other component(s) than those described here.

[0203] In the optional cooling enclosure 606, the battery 200 can be held by the bracket 608 as described above.

[0204] The cooling of the battery 200 in the cooling enclosure 606 can be achieved in any known or suitable manner, for example by circulating a cooling flow which may be a flow of dry air or a flow of inert gas such as argon. The cooling flow may be at ambient temperature or at a temperature lower than ambient temperature.

[0205] The cooling enclosure 606 can optionally be equipped with: - a means of VOC evacuation (not shown); and / or - a sensor for measuring VOC concentration (not shown); and / or - a temperature measurement sensor to ensure that the cell is properly cooled before it comes out of the machine; in a similar or identical manner to what has just been described for the heating chamber 602 or for the compression chamber 604.

[0206] Of course, the cooling enclosure 606 may include other component(s) than those described here.

[0207] In system 600, the heating chamber 602, the compression chamber 604, and the optional cooling chamber 606 are separate from one another. Of course, the invention is not limited to this embodiment.

[0208] In the example of FIGURES 6a-6c, each of the heating chambers 602 and compression chambers 604 respectively has its own means for circulating the heating flow and the exhaust flow, respectively. Of course, the invention is not limited to this embodiment.

[0209] FIGURES 7a-7c are schematic representations of another non-limiting embodiment of a system according to the present invention.

[0210] The 700 system of FIGURES 7a-7c can be used to extract and recover lithium from a battery comprising lithium, in particular metallic lithium, and even more particularly from battery 200 of [Fig.2].

[0211] System 700 can be used to implement a process according to the invention, for example any one of the processes 300, 400 or 500.

[0212] The system 700 includes, unlike the system 600, a single common enclosure 702 for heating and compressing the battery 200. Optionally, the system 700 may also include the cooling enclosure 606 of the system 600, separate from the common enclosure 702.

[0213] The common enclosure 702 is equipped only with the first circulation means 614r6143 described with reference to FIGURES 6a-6c. This first circulation means 614i-6143 circulates the heating flow during the heating stage to heat the battery. In addition, optionally, but preferably, the first circulation means 614r6143 circulates the heating flow during the battery compression stage to remove the VOCs released by the battery during said compression stage.

[0214] Optionally, the common enclosure 702 can be equipped with a sensor for measuring the concentration of VOCs in said common enclosure 702, such as, for example, sensor 616.

[0215] The common enclosure 702 includes a heating zone 704 in which the battery 200 is positioned during the heating stage.

[0216] The common enclosure 702 includes a compression zone 706 comprising a battery compression means 200, for example rollers 622.

[0217] In [Fig.7a], battery 200 is located in the heating zone 704, in [Fig.7b] battery 200 is located in the compression zone 706 and in [Fig.7c] battery 200 is located in the optional cooling enclosure 606.

[0218] FIGURES 8a-8c are schematic representations of another non-limiting embodiment of a system according to the present invention.

[0219] The 800 system of FIGURES 8a-8c can be used to extract and recover lithium from a battery comprising lithium, in particular metallic lithium, and even more particularly from battery 200 of [Fig.2].

[0220] System 800 can be used to implement a process according to the invention, for example any one of the processes 300, 400 or 500.

[0221] System 800 includes all the elements of system 600 in FIGURES 6a-6c except for the differences indicated below.

[0222] In the system 800, the outlet duct 6142 of the heating chamber 602 is connected to the inlet duct 624i of the compression chamber 604. Thus, the heating flow used in the heating chamber 602 is used as the exhaust flow in the compression chamber 604, separate from the heating chamber 602.

[0223] The system 800 comprises only the drive means 6143 and does not include the drive means 6243. The sensor 616 and / or the sensor 626 can act on the drive means 6143, directly or via a control module (not shown).

[0224] Of course, system 600, system 700 or system 800 respectively, may include other components than those described above, such as for example: a means of electrically recharging the 200 battery, and / or a means of removing electrical connectors from said battery 200, and / or a means of breaking the electrical connection between the positive electrodes of the 200 battery, and / or etc.

[0225] Of course, the invention is not limited to the detailed examples above.

Claims

Demands

1. A process (300;400;500) for extracting lithium from an electric battery (200) comprising metallic lithium, said process (300;400;500) comprising a lithium extraction phase (302;402;510), said extraction phase (302;402;510) comprising the following steps carried out, at least in part, in a chamber (602,604;702): - heating (304) of said battery (200) to a temperature, referred to as the processing temperature, greater than or equal to the melting temperature of metallic lithium; - compression (306) of said battery (200) to remove the molten lithium from the battery; characterized in that the heating step (304) is carried out by circulating, in said chamber (602;702), a hot stream, referred to as the heating stream, in contact with said battery (200).

2. Method (300;400;500) according to claim 1, characterized in that the heating step (304) and the compression step (306) are carried out in the same enclosure (702).

3. Method (300;400;500) according to claim 1, characterized in that the heating step (304) and the compression step (306) are carried out in separate enclosures.

4. A method (300;400;500) according to any one of the preceding claims, characterized in that it comprises a circulation (310) of a flow, called the evacuation flow, during the compression step (306), in particular to evacuate at least a part of volatile organic compounds, VOCs, released by the battery (200) during said compression step (306).

5. A process (300;400;500) according to any one of the preceding claims, characterized in that it comprises a measurement of the concentration of at least one volatile organic compound in the enclosure (602,604;702), during the extraction phase (302;402;510).

6. A method (300;400;500) according to any one of the preceding claims, characterized in that it comprises - a flow rate adjustment; and / or - a temperature adjustment; of the heating flow, respectively of the exhaust flow.

7. A method (300;400;500) according to any one of the preceding claims, characterized in that it comprises recovering at least some of the heat from at least one outgoing stream of the enclosure to heat at least one incoming stream into said enclosure.

8. System (600;700;800) for extracting lithium from an electric battery comprising lithium, said system comprising: - at least one heating means, in an enclosure (602;702), configured to heat said battery (200) to a temperature, said processing temperature, greater than or equal to the melting temperature of said metallic lithium; - at least one compression means (622) of said battery (200) to evacuate the molten lithium out of the battery (200); characterized in that the heating means comprises a first circulation means (614i-6143), in said enclosure (602;702), of a hot flow, said heating flow, coming into contact with said battery.

9. System (700) according to claim 8, characterized in that it comprises a common enclosure (702) in which the heating and compression of the battery are carried out.

10. System (600;800) according to claim 8, characterized in that it comprises: - a separate enclosure (602), called a heating enclosure, in which the heating of the battery (200) is carried out, and / or - a separate enclosure (604), called a compression enclosure, in which the compression of the battery (200) is carried out.

11. System according to the preceding claim, characterized in that it comprises a heating chamber for several compression chambers.

12. System (600) according to the preceding claim, characterized in that it comprises a second means (6242-6243) for circulating a flow, called evacuation flow, during the compression of the battery (200), in particular to evacuate at least a part of the VOCs released by the battery (200).

13. System (600;700;800) according to any one of claims 8 to 12, characterized in that it comprises a gas sensor (616,626) for measuring the concentration of at least one volatile organic compound.

14. System (600;700;800) according to any one of claims 8 to 13, characterized in that the first circulation means (614r 6143), respectively the second circulation means (614r614 3), is adjustable / controllable to adjust the flow rate and / or the flow temperature.

15. System according to any one of claims 8 to 14, characterized in that it comprises at least one means for recovering at least a part of the heat from at least one flow exiting an enclosure of said system, to heat at least one flow entering said enclosure, or another enclosure of said system.

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