Apparatus for extracting lithium from batteries comprising solid metallic lithium

Abstract

The invention relates to a method (300) for extracting lithium from an assembly of at least one battery cell of a battery comprising solid metallic lithium, such as a lithium-metal-polymer battery, said method (300) comprising an extraction phase (306) comprising the following steps:-positioning (308) said assembly in an orientation in which said assembly is oriented in a direction in which said assembly is oriented in a direction in which said assembly is oriented in a direction in which said assembly is oriented in a direction in which said assembly is oriented in a direction in which said assembly is oriented in a direction in which said assembly is oriented in a direction in which said assembly is oriented in a direction in which said assembly is oriented in a direction in which said assembly is oriented; a first edge of the assembly is located below a second edge of the assembly opposite the first edge, one or more negative electrodes extend from the first edge, and one or more positive electrodes extend from the second edge; and-heating (310) the assembly to a processing temperature greater than or equal to the melting temperature of the solid metallic lithium. The invention also relates to a device for implementing such a method.

Description

[0001] This application is a divisional application, and its original application is a PCT application with the application number PCT / EP2020 / 053209, the filing date of February 7, 2020, and it entered the Chinese national phase on August 5, 2021, with the application number 202080012795.1 and the title "Method for Extracting Lithium from Batteries Comprising Solid Metallic Lithium". Technical Field

[0002] The present invention relates to a method and an apparatus for extracting lithium from a battery comprising solid metallic lithium.

[0003] The field of the present invention is the field of batteries based on solid metallic lithium, and in particular the field of lithium-metal-polymer batteries, and more particularly the field of recycling of these batteries. Background Art

[0004] Batteries based on solid metallic lithium, such as lithium-metal-polymer batteries, are known. These batteries are increasingly used, for example, in electric vehicles or charging stations. Thus, the number of batteries has been continuously increasing over the years.

[0005] The service life of a battery is not infinite, and it seems necessary to recycle these batteries. Now, even at the end of their service life, the batteries still contain solid metallic lithium, which can be reused in other batteries or other fields and whose value cannot be underestimated.

[0006] However, there is currently no technology that allows solid metallic lithium to be recovered from batteries satisfactorily.

[0007] The object of the present invention is to overcome this drawback.

[0008] Another object of the present invention is to propose a method for recovering solid metallic lithium from components of at least one electrical energy storage unit.

[0009] Another object of the present invention is to propose a method for recovering solid metallic lithium from components of at least one electrical energy storage unit in a simple manner.

[0010] Another object of the present invention is to propose a method for recovering solid metallic lithium from components of at least one electrical energy storage unit in an efficient manner while limiting and managing the potential short-circuit effects during recovery. Summary of the Invention

[0011] The first solution proposed by the present invention

[0012] According to a first solution, the present invention makes it possible to achieve at least one of these objects by a method for extracting lithium from the components of at least one cell of a battery comprising solid metallic lithium, such as a lithium-metal-polymer battery, said method comprising an extraction phase, which extraction phase comprises the following steps:

[0013] - Positioning the component in such an orientation that a first edge of the component is located below a second edge of the component opposite the first edge, from which first edge one or more negative electrodes extend and from which second edge one or more positive electrodes extend.

[0014] - Heating the component to a temperature greater than or equal to the melting temperature of the solid metallic lithium, which temperature is referred to as the treatment temperature.

[0015] The method according to the invention proposes to recover lithium from a battery comprising solid lithium by treating the cells constituting the battery either individually or together.

[0016] Furthermore, the method according to the invention proposes to recover metallic lithium, preferably solid metallic lithium, from the components of at least one cell in which the lithium is in a liquid state by heating the components of the cell to a treatment temperature greater than the melting temperature of solid-state metallic lithium. Once the metallic lithium has melted, the metallic lithium will drain naturally, in whole or in part, from each cell under the action of gravity.

[0017] Thus, the method according to the invention allows for a simple and not very complex recovery of solid metallic lithium.

[0018] Furthermore, the method according to the invention proposes a specific orientation for each cell, each cell having a minimum inclination angle such that a first edge from which the negative electrode extends is located below the level of a second edge opposite the first edge from which the positive electrode extends. This orientation of each cell makes it possible, on the one hand, to facilitate the outflow of molten lithium from the cell by gravity and, on the other hand, to avoid contact between the molten lithium and the positive electrode 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.

[0019] In the present application, an "electric energy storage cell" means a component comprising at least:

[0020] - A negative electrode formed of or comprising a layer of solid metallic lithium;

[0021] - A positive electrode,

[0022] - A solid electrolyte, which particularly comprises a lithium salt, which is arranged between the positive electrode and the negative electrode, and

[0023] - A current collector on the positive electrode side.

[0024] In the present application, "solid metallic lithium" can include:

[0025] - Pure metallic lithium; or

[0026] - A combination of at least one metallic lithium alloy; or

[0027] - A combination of pure metallic lithium and at least one metallic lithium alloy.

[0028] When "solid metallic lithium" includes a combination of different forms of lithium (such as those described above) having different melting temperatures, the heating step heats the components of the battery cell to a processing temperature greater than or equal to the following temperature:

[0029] - The lowest of the different melting temperatures; and

[0030] - Preferably, the highest of the different melting temperatures.

[0031] According to a non-limiting example of an embodiment, the processing temperature is greater than or equal to 180.5 °C.

[0032] According to an example of an embodiment, the processing temperature is less than or equal to the highest temperature, for example 300 °C.

[0033] The component can include a single or only one battery cell.

[0034] The component can include a plurality of battery cells assembled or in particular stacked in an assembly direction. The component direction can be perpendicular to the plane formed by each battery cell.

[0035] In particular, the component can correspond to a battery in which the battery cells are connected in series.

[0036] According to a preferred embodiment, the positioning step can perform a vertical positioning of the battery cell component, with the first edge located below.

[0037] Thus, the gravitational flow of the molten lithium flowing out of each battery cell is improved.

[0038] In addition, the risk of contact between the molten lithium and one or more positive electrodes is reduced or zero.

[0039] Preferably, the step of heating the battery cell component can be carried out under an inert gas.

[0040] Thus, the method according to the present invention reduces the risk of accidents, in particular the risk of fire.

[0041] Furthermore, the method according to the invention makes it possible to avoid the formation of contaminating compounds generated by unwanted or uncontrolled physical and chemical reactions during lithium extraction.

[0042] According to a non-limiting example, the inert gas can be or include any of the following gases: helium (He), neon (Ne), argon (Ar), krypton (Kr), xenon (Xe), and radon (Rn).

[0043] According to another embodiment, the step of heating the battery cell assembly can be carried out under vacuum.

[0044] According to a particularly advantageous feature, the method according to the invention can also include the step of charging the battery cell assembly before the extraction phase, said extraction phase being applied to the charged assembly.

[0045] The fact of charging one or more battery cells and carrying out an extraction phase on the charged battery cells makes it possible to increase the lithium extraction yield. In fact, the charging of the battery cells makes it possible to shift the lithium ions towards the negative electrode, which allows an increase in the recoverable amount of lithium.

[0046] Each battery cell can be charged individually or by charging the battery cell assembly.

[0047] According to a particularly advantageous embodiment, the extraction phase can also include the step of compressing the battery cell assembly.

[0048] Thus, the molten lithium is forced out of each battery cell, which increases the amount of lithium recovered.

[0049] The compression step can be carried out continuously throughout the extraction phase. In this case, throughout the duration of the extraction phase, each battery cell is subjected to partial or total compression.

[0050] Alternatively, the compression step can be carried out one or more times individually during the extraction phase. In this case, the extraction phase includes moments when the battery cell assembly is not subjected to compression.

[0051] Advantageously, the compression step can apply compression to the surface of the assembly by sweeping the surface of the battery cell assembly from a second edge to a first edge. Thus, the molten lithium is progressively conveyed / guided towards the first edge from which one or more negative electrodes extend, which increases the amount of lithium recovered and reduces the risk of contact between the lithium and one or more positive electrodes.

[0052] For example, the compression step can be carried out by passing the battery cell assembly between two rollers.

[0053] According to another example, the compressing step can be performed by pressing the battery cell assembly against a bearing surface by means of compression rollers.

[0054] The compression can be applied by continuous passes, each pass sweeping the surface of the battery cell assembly from the second edge to the first edge.

[0055] The gap between the compression rollers, or the gap between a compression roller and the bearing surface, can correspond to the thickness of the battery cell assembly minus the thickness of one or more solid metallic lithium layers. This allows compression to be applied while solid lithium remains in the battery cell assembly.

[0056] The gap between the two compression rollers or between a compression roller and the bearing surface can be reduced with successive passes in order to still apply compression to the battery cell assembly.

[0057] The speed of passage between the compression rollers, or the speed of one compression roller, and more generally the sweeping speed, can be from a few millimeters to several tens of millimeters per second.

[0058] Furthermore, the method according to the invention can include the step of removing at least one electrical connector (also called a "crimp connector") from at least one battery cell before the extraction phase.

[0059] This allows for the handling of the battery cell assembly to be facilitated.

[0060] Furthermore, the method according to the invention can include, before the extraction phase, the step of removing excess material at at least one edge of the battery cell assembly, and in particular at the level of each edge.

[0061] According to another aspect of the invention, there is provided a device for extracting lithium from an assembly of at least one battery cell of a battery comprising solid metallic lithium (such as a lithium-metal-polymer battery), the device comprising:

[0062] - means for positioning the assembly in an orientation in which a first edge of the assembly is located below a second edge of the assembly opposite the first edge, one or more negative electrodes extending from the first edge and one or more positive electrodes extending from the second edge; and

[0063] - heating means configured to heat the assembly to a processing temperature greater than or equal to the melting temperature of the solid metallic lithium.

[0064] Generally, the device includes means configured to implement any combination of at least one of the above features, which are not described in detail here for the sake of brevity.

[0065] In particular, the heating means can include an oven.

[0066] Advantageously, the oven can be filled with an inert gas or placed under vacuum.

[0067] The device according to the invention can also comprise means for compressing the battery cell assembly.

[0068] The compressing means can comprise at least one roller.

[0069] In particular, the compressing means can comprise a single roller that presses the battery cell assembly against a bearing surface. The bearing surface can be heated to accelerate the temperature rise of the battery cell assembly.

[0070] Alternatively, the compressing means can comprise two rollers through which the battery cell assembly passes between them.

[0071] Generally, the compressing means can be configured to apply continuous compression throughout the extraction phase.

[0072] Alternatively, the compressing means can be configured to apply one or more compressions discontinuously over time during the extraction phase. In this case, the extraction phase includes moments when the battery cell assembly is not subjected to compression.

[0073] Advantageously, the compressing step can be configured to apply compression stepwise from a second edge to a first edge or by sweeping across the surface of the battery cell assembly with a constant or variable value. Thus, the molten lithium is gradually conveyed / guided towards the first edge located at a lower position, which increases the amount of lithium recovered and reduces the risk of contact between the lithium and one or more positive electrodes.

[0074] In the case of using one or two compression rollers, compression can be applied to the battery cell assembly by successive passes. Each pass applies compression by sweeping across the surface of the battery cell assembly from the second edge to the first edge. At the end of each pass, compression can be stopped by withdrawing the roller or by withdrawing the roller from the bearing surface to return to the second edge to start a new pass.

[0075] The distance between the rollers, or the distance between the compression roller and the bearing surface, can decrease with successive passes, particularly between two successive passes.

[0076] The method according to the invention can be implemented to process a plurality of battery cell assemblies, particularly when a plurality of battery cell assemblies form a battery pack and are connected in parallel within said battery pack.

[0077] At least two battery cell assemblies can be aligned side by side without overlapping, for example, in a direction parallel to the first edge.

[0078] In this case, compression can be applied to at least two battery cell assemblies by means of one and the same compression device, namely a set of rollers, or a single roller cooperating with a bearing surface.

[0079] The second solution proposed by the present invention

[0080] According to the second solution, the present invention enables at least one of these objects to be achieved by a method for extracting lithium from an assembly of at least one cell of a battery comprising solid metallic lithium, such as a lithium-metal-polymer battery, said method comprising an extraction phase which includes the following steps:

[0081] - Positioning the assembly in such an orientation that a first edge of the assembly is located above a second edge of the assembly opposite the first edge, from which one or more negative electrodes extend, and from which one or more positive electrodes extend from the second edge.

[0082] - Immersing the battery cell assembly in a liquid having a density greater than that of liquid lithium and being electrically insulating; and

[0083] - Heating the assembly to a temperature greater than or equal to the melting temperature of the solid metallic lithium, said temperature being referred to as the treatment temperature.

[0084] The method according to the present invention proposes to recover lithium from a battery comprising lithium by treating the battery cells constituting the battery either individually or together.

[0085] Furthermore, the method according to the present invention proposes to recover metallic lithium from an assembly of at least one cell in which lithium is in a liquid state by heating the assembly of the battery cells to a treatment temperature greater than the melting temperature of solid metallic lithium. Once molten, the metallic lithium will naturally drain from each cell under the influence of the density difference. Thus, the method according to the present invention allows for a simple and not very complex recovery of solid metallic lithium.

[0086] Furthermore, the method according to the present invention proposes a specific orientation for each battery cell, each battery cell having a minimum inclination angle such that a first edge from which a negative electrode extends is located above the level of a second edge opposite the first edge from which a positive electrode extends. This orientation of each battery cell enables on the one hand the promotion of the outflow of molten lithium from the battery cell by the density difference and on the other hand the avoidance of contact between the molten lithium and the positive electrode or the current collector of the positive electrode, such contact being able to cause an electrical short circuit, such a short circuit being able to cause a fire. Furthermore, immersing the battery cell assembly in a liquid enables the improvement of the dissipation of heat from the battery cell, particularly during a short circuit, and thus significantly limits its effects.

[0087] In the present application, an "electric energy storage battery unit" refers to a component that at least includes the following:

[0088] - A negative electrode formed of or including a solid metallic lithium layer;

[0089] - A positive electrode,

[0090] - A solid electrolyte, which particularly includes a lithium salt and is disposed between the positive electrode and the negative electrode, and

[0091] - A current collector on the positive electrode side.

[0092] In the present application, "density" refers to the ratio between the mass density of the liquid under discussion and the mass density of water.

[0093] In the present application, "solid metallic lithium" can include:

[0094] - Pure metallic lithium; or

[0095] - A combination of at least one metallic lithium alloy; or

[0096] - A combination of pure metallic lithium and at least one metallic lithium alloy.

[0097] When "solid metallic lithium" includes a combination of different forms of lithium (such as those mentioned above) having different melting temperatures, the heating step heats the components of the battery unit to a processing temperature greater than or equal to the following temperature:

[0098] - The lowest of the different melting temperatures; or preferably, the lowest of the different melting temperatures, or

[0099] - A combination of different temperatures, for example, or a temperature gradient extending from a first edge to a second edge.

[0100] According to a non-limiting example of an embodiment, in the case of using pure metallic lithium, the processing temperature is greater than or equal to 180.5 °C.

[0101] According to an example of an embodiment, the processing temperature is less than or equal to the highest temperature, for example, 300 °C.

[0102] The component can include a single or only one battery unit.

[0103] The component can include a plurality of battery units assembled or particularly stacked in the assembly direction. The component direction can be perpendicular to the plane formed by each battery unit.

[0104] In particular, the component can correspond to a battery in which the battery units are connected in series.

[0105] According to a preferred embodiment, the positioning step enables the vertical positioning of the battery cell assembly, with the first edge positioned upward.

[0106] Thus, the flow of molten lithium flowing out of each battery cell through the density difference is improved.

[0107] Furthermore, the risk of contact between the molten lithium and one or more positive electrodes is reduced or zero.

[0108] Preferably, the immersion step is carried out by completely immersing the battery cell assembly in a liquid.

[0109] Thus, the method according to the invention reduces the risk of accidents, especially the risk of fire. In addition, the method according to the invention makes it possible to avoid the formation of contaminating compounds generated by unwanted or uncontrolled physico-chemical reactions during the extraction of lithium, in particular by controlling the treatment temperature and the density of the liquid so that only lithium or a lithium alloy can be extracted.

[0110] According to a particularly advantageous feature, the method according to the invention can also include a step of charging the battery cell assembly before the extraction phase, said extraction phase being applied to the charged assembly.

[0111] The fact of charging one or more battery cells and performing an extraction phase on the charged battery cells makes it possible to increase the lithium extraction yield. In fact, the charging of the battery cells makes it possible to shift the lithium ions towards the negative electrode, which allows an increase in the recoverable amount of lithium.

[0112] Each battery cell can be charged individually or by charging the battery cell assembly.

[0113] According to a particularly advantageous embodiment, the extraction phase can also include a step of compressing the battery cell assembly.

[0114] Thus, the molten lithium is forced out of each battery cell, which increases the amount of lithium recovered and improves the kinetics of the process.

[0115] The compression step can be carried out continuously throughout the extraction phase. In this case, throughout the duration of the extraction phase, each battery cell is subjected to partial or total compression.

[0116] Alternatively, the compression step can be carried out one or more times individually during the extraction phase. In this case, the extraction phase includes moments when the battery cell assembly is not subjected to compression.

[0117] Advantageously, the compressing step can apply compression to the surface of the battery cell assembly by sweeping the surface of the battery cell assembly from the second edge to the first edge. Thus, the molten lithium is gradually conveyed / guided towards the first edge from which one or more negative electrodes extend, which increases the amount of lithium recovered and reduces the risk of contact between the lithium or lithium alloy and one or more positive electrodes.

[0118] For example, the compressing step can be carried out by passing the battery cell assembly between two rollers.

[0119] According to another example, the compressing step can be carried out by pressing the battery cell assembly against a bearing surface by a compression roller.

[0120] The compressing step can be applied by continuous passing, each pass starting from the second edge and sweeping the surface of the battery cell assembly to the first edge.

[0121] The gap between the compression rollers, or the gap between the compression roller and the bearing surface, can correspond to the thickness of the battery cell assembly minus the thickness of one or more solid metallic lithium layers. This enables compression to be applied while solid lithium remains in the battery cell assembly.

[0122] The gap between two compression rollers or between the compression roller and the bearing surface (also called a platen) can be reduced with successive passes in order to still apply compression to the battery cell assembly.

[0123] The passing speed between the compression rollers, or the speed of the compression roller cooperating with the platen, and more generally the sweeping speed, can be from a few millimeters to several tens of millimeters per second.

[0124] Furthermore, the method according to the invention can include the step of removing at least one electrical connector (also called a "crimp connector") from the battery cell before the extraction phase.

[0125] This enables the handling of the battery cell assembly to be facilitated.

[0126] Furthermore, the method according to the invention can include, before the extraction phase, the step of removing excess material at at least one edge of the battery cell assembly, and in particular at the level of each edge.

[0127] According to another aspect of the same invention, there is provided a device for extracting lithium from an assembly of at least one battery cell (such as a lithium-metal-polymer battery) comprising solid metallic lithium, the device comprising:

[0128] - A device for positioning the component in an orientation in which a first edge of the component is above a second edge of the component opposite the first edge, with one or more negative electrodes extending from the first edge and one or more positive electrodes extending from the second edge;

[0129] - An oven filled with a liquid that is denser than liquid lithium and electrically insulating; and

[0130] - A heating device configured to heat the component to a processing temperature greater than or equal to the melting temperature of solid metallic lithium.

[0131] Generally, the device includes means configured to implement any combination of at least one of the above features, which are not described in detail here for the sake of brevity.

[0132] The liquid can be a natural or synthetic oil, which includes the following physicochemical properties:

[0133] · Hydrophobic and non-reactive with respect to lithium,

[0134] · Electrically insulating,

[0135] · Its density is greater than the density of lithium,

[0136] · Thermally stable above the melting temperature of lithium (i.e., 180.5 °C),

[0137] · As high a flash point and autoignition point as possible.

[0138] The device according to the invention can also include means for compressing the battery cell assembly.

[0139] The compressing means can include at least one roller.

[0140] In particular, the compressing means can include a single roller that presses the battery cell assembly against a bearing surface. The bearing surface can be heated to accelerate the temperature rise of the battery cell assembly.

[0141] Alternatively, the compressing means can include two rollers through which the battery cell assembly passes.

[0142] Generally, the compressing step can be configured to apply continuous compression throughout the extraction phase.

[0143] Alternatively, the compressing means can be configured to apply one or more compressions discontinuously over time during the extraction phase. In this case, the extraction phase includes moments when the battery cell assembly is not subjected to compression.

[0144] Advantageously, the compressing device can be configured to apply compression step by step from a second edge to a first edge, or by sweeping across the surface of the battery cell assembly, with a constant or variable value. Thus, the molten lithium is gradually conveyed / guided towards the first edge located at a lower position, which increases the amount of lithium recovered and reduces the risk of contact between the lithium and one or more positive electrodes.

[0145] In the case of using one or two compression rollers, compression can be applied to the battery cell assembly by continuous passes. Each pass applies compression by sweeping across the surface of the battery cell assembly from the second edge to the first edge. At the end of each pass, compression can be stopped by withdrawing the roller or by withdrawing the roller from the bearing surface, to return to the second edge in order to start a new pass.

[0146] The distance between the rollers, or the distance between the compression roller and the bearing surface, can be reduced with continuous passes, and in particular between two consecutive passes.

[0147] The method according to the present invention can be implemented to process a plurality of battery cell assemblies, in particular a plurality of battery cell assemblies form a battery pack and are connected in parallel within the battery pack.

[0148] At least two battery cell assemblies can be aligned side by side, without overlapping, for example, in a direction parallel to the first edge.

[0149] In this case, compression can be applied to at least two battery cell assemblies by one and the same compressing device, namely a set of rollers, or a single roller cooperating with the bearing surface. Description of the Drawings

[0150] Other advantages and features will become apparent by reading the detailed description of non - limiting embodiments and the drawings, in which:

[0151] - Figure 1 is a schematic view of a non - limiting example of a battery cell within the meaning of the present invention;

[0152] - Figure 2 is a schematic view of a non - limiting example of a battery cell assembly within the meaning of the present invention;

[0153] - Figure 3 is a schematic view of a first non - limiting example of a method according to the present invention following the proposed first solution;

[0154] - Figure 4 is a schematic view of a second non - limiting example of a method according to the present invention following the proposed second solution; and

[0155] - Figure 5Schematic diagram of a non - limiting example of an apparatus according to the invention that follows the proposed first solution;

[0156] - Figure 6 Schematic diagram of a first non - limiting example of a method according to the invention that follows the proposed second solution;

[0157] - Figure 7 Schematic diagram of a second non - limiting example of a method according to the invention that follows the proposed second solution;

[0158] - Figure 8 Schematic diagram of a non - limiting example of an apparatus according to the invention that follows the proposed second solution. Detailed implementation mode

[0159] It should be understood that the embodiments described herein are in no way restrictive. If the selection of features is sufficient to confer a technical advantage or to distinguish the invention from the state of the art, variants of the invention can be envisaged that include only the selection of the features described below, the selection of which is independent of the other features described. This selection includes at least one preferably functional feature without structural details or with only some structural details, provided that this part of the structural details alone is sufficient to confer a technical advantage or to distinguish the invention from the prior art.

[0160] In the drawings, elements common to several drawings are denoted by the same reference numerals.

[0161] In this application, "density" refers to the ratio between the mass density of the liquid in question and the mass density of water.

[0162] The liquid can be a natural or synthetic oil, which includes the following physicochemical properties:

[0163] · Hydrophobic and non - reactive with respect to lithium,

[0164] · Electrically insulating,

[0165] · Its density is greater than the density of lithium,

[0166] · Thermally stable above the melting temperature of lithium (i.e., 180.5 °C),

[0167] · As high a flash point and auto - ignition point as possible.

[0168] Figure 1 Schematic diagram of a non - limiting example of a battery cell within the meaning of the invention, regardless of which of the two proposed solutions is implemented.

[0169] Figure 1The battery cell 100 shown in [the figure] includes a negative electrode 102, which is formed of or includes a solid metallic lithium layer.

[0170] The battery cell 100 further includes a positive electrode 104. The positive electrode 104 is generally formed of a composite material layer based on a polymer and an active material.

[0171] A solid electrolyte layer 106 is disposed between the negative electrode 102 and the positive electrode 104. The solid electrolyte layer 106 can include, for example, a lithium salt.

[0172] The battery cell 100 further includes a current collector 108 on the side of the positive electrode 104. The current collector 108 is generally made of aluminum.

[0173] Conventionally, the negative electrode 102 of the battery cell 100 extends beyond the other elements of the battery cell 100 on one side of the first edge 110 of the battery cell 100, here extending to the right side of the figure; and the positive electrode 104 and / or the current collector 108 (the current collector 108 being connected to the positive electrode 104) of the battery cell 100 extend beyond the other elements of the battery cell 100 on one side of the second edge 112 opposite the first edge 110. In the example shown, only the current collector 108 extends beyond the assembly 100 on the second edge 112 of the assembly, here extending to the left side of the figure. In other examples, the extension can involve only the positive electrode 104, or can also involve the positive electrode 104 and the current collector 108.

[0174] Of course, Figure 1 the battery cell 100 shown in [the figure] is a very simplified version of an implementation, given in a non-limiting illustrative manner. A battery cell within the meaning of the present invention can include layers different from those shown, or more layers, or layers having a composition different from the composition given here as a non-limiting example.

[0175] Figure 2 is a schematic diagram of a non-limiting example embodiment of a battery cell assembly within the meaning of the present invention, regardless of which of the two proposed solutions is implemented.

[0176] Figure 2 The battery cell assembly 200 shown in [the figure] includes one or more battery cells within the meaning of the present invention.

[0177] In particular, the battery cell assembly 200 includes a plurality of identical battery cells 1001 - 100n, which are assembled in a direction 202 perpendicular to the plane of each battery cell 100i layer.

[0178] Each battery cell 100i can be Figure 1 the same as the battery cell 100 in [the figure].

[0179] In addition, a positive electrode 204i and a current collector 206i connected thereto are disposed between two adjacent battery cells 100i-100i+1 where i < n.

[0180] Example of an embodiment according to the first proposed solution

[0181] Figure 3 is a schematic view of a first non-limiting example of an embodiment of a method according to the invention following the first proposed solution;

[0182] Figure 3 The method 300 shown therein includes a first optional step 302 during which the electrical connectors of the battery cell assembly are removed, and in particular the current concentrators (also referred to as "crimp connectors").

[0183] During the optional step 304, the excess material, in particular solid metallic lithium, is removed at each lateral edge level of the battery cell assembly.

[0184] Then, the method 300 includes a stage 306 of extracting metallic lithium from the battery cells.

[0185] The extraction stage 306 includes a step 308 which positions the battery cell assembly in an orientation in which a first edge from which one or more negative electrodes extend is at a lower level than a second edge from which one or more positive electrodes and current collectors extend. In particular, step 308 positions the battery cell assembly in the vertical direction, i.e., parallel to the gravity vector, such that one or more negative electrodes extend downward from their edges. Preferably, but by no means restrictively, the battery cell assembly remains in this orientation throughout the extraction stage 306.

[0186] The extraction stage 306 further includes a step 310 which heats the battery cell assembly to a treatment temperature greater than or equal to the melting temperature of the solid metallic lithium present in the battery cell assembly, for example a temperature of 180.5 °C. This temperature will cause the solid metallic lithium to melt and be extracted from each battery cell by natural drainage under the action of gravity. Preferably, but by no means restrictively, the battery cell assembly is maintained at this temperature throughout the extraction stage 306.

[0187] Advantageously, the heating step is carried out in a closed enclosure filled with an inert gas.

[0188] The extraction stage 306 can also include an optional step 312 that compresses the cell stack to flush molten lithium out of each cell. The compression can be carried out continuously throughout all or part of the extraction stage 306. Alternatively, the compression step 312 can be iterated discontinuously multiple times during the extraction stage 306. Preferably, the compression step 312 starts from the second edge from which one or more positive electrodes extend and moves towards the first edge from which one or more negative electrodes extend, applying compression gradually or by sweeping across the surface of the cell stack.

[0189] Figure 4 is a schematic illustration of another non-limiting example embodiment of a method according to the invention following the proposed first solution.

[0190] Figure 4 The method 400 shown in Figure 3 includes all the steps of method 300 in

[0191] Prior to the steps of method 300, method 400 also includes a step 402 of recharging the processed cells.

[0192] Each cell can be recharged partially or fully.

[0193] The fact of charging each cell makes it possible to increase the amount of lithium available for extraction, since recharging causes lithium ions to migrate to the negative electrode of the cell.

[0194] Figure 5 is a schematic illustration of a non-limiting example embodiment of a device according to the invention following the proposed first solution.

[0195] Figure 5 The device 500 shown in Figure 3 and 4 can be used to implement the methods according to the invention, and in particular

[0196] The device 500 makes it possible to extract and recover part or all of the lithium from cells comprising solid metallic lithium (such as Figure 1 the cell 100 in Figure 2 or from a cell stack (such as

[0197] The device 500 includes an oven 502 filled with an inert gas or placed under vacuum, which is configured to heat the cells to a processing temperature greater than or equal to the melting temperature of the solid metallic lithium present in the cells, such as 180.5 °C or 181 °C.

[0198] Device 500 includes a pair of clamps 504 for holding the battery cell 100 or the battery cell assembly 200 in a vertical or at least inclined position in which the first edge 110 is positioned horizontally below the second edge 112. Each clamp 504 is movably mounted on a vertical rail 506 so as to vertically displace the battery cell or the battery cell assembly 200.

[0199] Device 500 further includes a pair of rollers 508, the gap between which corresponds to the thickness of the battery cell 100 or the battery cell assembly 200 minus the thickness of the solid lithium metal layer. The pair of rollers is positioned such that when the clamps 504 are displaced upward, the battery cell 100, the battery cell assembly 200 respectively pass between the rollers 508 starting from the second edge 112. Thus, the rollers move from the second edge 112 and toward the first edge 110 to gradually apply compression to the battery cell 100, the battery cell assembly 200 respectively.

[0200] The device further includes a container 510 for recovering the molten lithium metal flowing out of each battery cell under the action of gravity. The container 510 must be inert with respect to lithium.

[0201] Example of an embodiment according to the proposed second solution

[0202] Figure 6 is a schematic diagram of a non-limiting example of an embodiment of a method according to the invention that follows the proposed second solution.

[0203] Figure 6 The method 600 shown in includes a first optional step 602 during which the electrical connectors of each battery cell, also known as "crimp connectors", are removed.

[0204] During the optional step 604, the excess material at each lateral edge level of the battery cell assembly is removed.

[0205] Then, the method 600 includes a stage 606 of extracting lithium metal from the battery cell.

[0206] The extraction stage 606 includes a step 608 that positions the battery cell assembly in an orientation in which the first edge 110 from which one or more negative electrodes 102 extend is at a higher level in the vertical direction than the second edge 112 from which one or more positive electrodes 104 and the current collector extend. In particular, step 608 positions the battery cell assembly such that in the vertical direction, i.e., parallel to the gravity vector, one or more negative electrodes 102 extend downward from its edge. Preferably, but by no means restrictively, the battery cell assembly remains in this orientation throughout the extraction stage 606.

[0207] The extraction stage 606 includes a step 609 of immersing the battery cell assembly in a liquid 850 (see Figure 8 ). For example, in the embodiment shown in Figure 8 , the liquid 850 is a natural or synthetic oil, such as paraffin oil, which has the following physico-chemical properties:

[0208] · Hydrophobic and non-reactive with respect to lithium,

[0209] · Electrically insulating,

[0210] · Its density is greater than the density of lithium,

[0211] · Thermally stable above the melting temperature of lithium (i.e., 180.5 °C), and

[0212] · The flash point and the autoignition point are as high as possible, for example, the temperature is higher than 600 °C, and at least higher than the processing temperature of the battery cell.

[0213] The immersion step 609 is carried out by immersing the battery cell assembly 200 in the liquid 850 such that the liquid 850 completely covers the battery cell assembly 200.

[0214] This immersion step 609 is particularly advantageous for promoting a significant heat exchange between the battery cell and the liquid 850, which limits the risk of overheating of the battery cell and the dissipation of the heat generated during a short circuit and improves the heating kinetics.

[0215] The extraction stage 606 further includes a step 610 of heating the battery cell assembly to a processing temperature greater than or equal to the melting temperature of the solid metallic lithium present in the battery cell assembly, for example, a temperature of 180.5 °C. In the presented embodiment, the liquid 850 is heated by an oven and the heat is transferred to the battery cell assembly. Once above the melting temperature of lithium, this temperature causes the solid metallic lithium to melt and is extracted from each battery cell by natural drainage under the action of gravity. Preferably, but not exclusively, the battery cell assembly is maintained at this temperature throughout the extraction stage 606. The processing temperature shall not exceed the degradation temperature of the liquid 850 (specific to each liquid 850), above which the liquid 850 degrades. In other words, the liquid 850 changes its properties above a threshold temperature such that the above characteristics are no longer met. Ideally, the degradation temperature of the liquid must be higher than +40 °C (and for example, between +60 °C and +60 °C) with respect to the melting temperature of lithium.

[0216] Thus, the method for extracting lithium from a battery makes it possible to limit the influence of the short-circuit potential by allowing lithium to flow through the first edge 110 from which one or more negative electrodes 102 extend, and makes it possible to control the short circuit by immersing the battery cell assembly in a liquid that does not react with lithium and improving the heat dissipation from the battery cell assembly (especially during a short circuit).

[0217] The extraction phase 606 can also include an optional step 612 that compresses the cell assembly to accelerate the extraction of molten lithium from each cell. The compression can be performed continuously throughout all or part of the extraction phase 606. Alternatively, the compression step 612 can be repeated iteratively discontinuously multiple times during the extraction phase 606. Preferably, the compression step 612 starts from the second edge 112 from which one or more positive electrodes 104 extend and moves towards the first edge 110 from which one or more negative electrodes 102 extend, applying compression stepwise or by sweeping across the surface of the cell assembly.

[0218] Figure 7 is a schematic view of another non-limiting example of an embodiment of a method according to the present invention that follows the proposed second solution.

[0219] Figure 7 The method 700 shown in Figure 6 includes all the steps of the method 600 in

[0220] Before the steps of the method 600, the method 700 further includes a step 702 of recharging one or more of the processed cells.

[0221] Each cell can be recharged partially or fully.

[0222] The fact of charging each cell makes it possible to increase the amount of lithium available for extraction, since recharging causes lithium ions to migrate to the negative electrode of the cell, which improves the amount of lithium extracted and the kinetics of the operation.

[0223] Figure 8 is a schematic view of a non-limiting example of an embodiment of a device according to the present invention that follows the proposed second solution.

[0224] Figure 8 The device 800 shown in Figure 6 and 7 can be used to implement the methods 600 and 700 in

[0225] The device 800 makes it possible to extract and recover part or all of the lithium from cells comprising solid metallic lithium (such as Figure 1 the cell 100 in Figure 2 or from a cell assembly (such as

[0226] Device 800 includes an oven 802 filled with a liquid 850, which is configured to heat the battery cell to a processing temperature greater than or equal to the melting temperature of the solid metallic lithium present in the battery cell, such as 180.5 °C or 181 °C. In the presented embodiment, the liquid 850 is heated by the oven 802 and transfers heat to the battery cell assembly.

[0227] Device 800 includes a pair of clamps 804 for holding the battery cell 100 or the battery cell assembly 200 in a vertical or at least inclined position, in which the first edge 110 is positioned horizontally above the second edge 112. Each clamp 804 is movably mounted on a vertical rail 806 so as to vertically displace the battery cell 100 or the battery cell assembly 200.

[0228] The liquid 850 completely covers the battery cell assembly such that the first edge 110 is positioned below the level of the liquid 850.

[0229] Device 800 further includes a pair of rollers 808, the gap between which corresponds to the thickness of the battery cell 100 or the battery cell assembly 200 minus the thickness of one or more solid layers of metallic lithium. The pair of rollers is positioned such that when the clamps 804 are displaced upwards, the battery cell 100, the battery cell assembly 200 respectively pass between the rollers 808 starting from the second edge 112. Thus, the rollers move starting from the second edge 112 and towards the first edge 110 to apply compression to the battery cell 100, the battery cell assembly 200 respectively step by step.

[0230] Of course, the present invention is not limited to the examples described in detail above.

[0231] For example, the composition of the battery cell including solid metallic lithium can be different from Figure 1 the composition indicated therein.

[0232] In addition, the device according to the present invention can include devices different from Figure 5 and Figure 7 those shown therein, such as means for cutting off the electrical connectors from the battery cell, means for cutting off the excess parts on one or each edge.

[0233] For example, the clamps 504 and 804 can be fixed, and the rollers 508 and 808 can be movable and can compress the battery cell assembly from top to bottom, or from bottom to top according to this embodiment.

[0234] In addition, a single oven and multiple pairs of rollers dedicated to one battery cell or battery cell assembly can be used.

[0235] A pair of rollers can be operated to process several adjacent battery cell assemblies simultaneously.

[0236] As an example, step 609 can be carried out by submerging the battery cell 100 or the battery cell assembly 200 in the liquid 850, or by filling the oven 802 with the liquid 850 such that the liquid 850 covers the battery cell assembly 200 and the battery cell 100 respectively.

[0237] It should be noted that the orientation of the first edge 110 of the assembly from which one or more negative electrodes 102 extend is a function of the density of the fluid in which the battery cell 100 or the battery cell assembly 200 is submerged. In the case where the fluid is a gas, which is covered by the first solution proposed by the present invention, the first edge 110 will be located below the second edge 112 from which one or more positive electrodes 104 extend, because the density of the gas is lower than that of lithium. In the case where the fluid is a liquid with a density greater than that of lithium, which is covered by the second solution proposed by the present invention, the first edge 110 will be located above the second edge 112.

[0238] In the case where the fluid is a liquid with a density less than that of lithium, the orientation of the first edge 110 will be below the second edge 112, as shown in the first embodiment.

[0239] Furthermore, respectively through the rollers 508 and 808, the compression direction of the battery cell 100 is more conducive to compressing the battery cell from the second edge 112 to the first edge 110. Therefore, depending on the density of the fluid, the compression direction is inconsistent, as can be seen in the examples shown in Figure 5 and Figure 8 as visible.

[0240] The first edge 110 can be characterized in that it defines the side through which lithium must flow once it is in a liquid state.

Claims

1. An apparatus (500) for extracting lithium from a component (200) of at least one cell (100) of a battery comprising solid metallic lithium, the apparatus (500) comprising: - Positioning means (504) configured to position the component in an orientation in which a first edge (110) of the component (200) is located below a second edge (112) of the component opposite the first edge (110), one or more negative electrodes (102) extending from the first edge and one or more positive electrodes (104) extending from the second edge; and - Heating means (502) configured to heat the component (200) to a processing temperature greater than or equal to the melting temperature of the solid metallic lithium.

2. The device (500) according to claim 1, characterized in that, The positioning means (504) is configured for vertical positioning of the component (200) of the cell, wherein the first edge (110) is located below.

3. The device (500) according to claim 1 or 2, characterized in that, The positioning means comprises a pair of clamps for holding the component of the cell.

4. The device (500) according to claim 1 or 2, characterized in that, The heating means comprises an oven (502) filled with an inert gas.

5. The device (500) according to claim 1 or 2, characterized in that, The heating means comprises an oven (502) placed under vacuum.

6. The device (500) according to claim 1 or 2, characterized in that, It comprises compressing means (508) for the component (200) of the cell.

7. The device (500) according to claim 6, wherein, The compressing means comprises a single roller pressing the component of the cell against a bearing surface.

8. The device (500) according to claim 6, characterized in that, The compressing means comprises two rollers (508) through which the component of the cell is passed.

9. The device (500) according to claim 1, wherein, The battery is a lithium-metal-polymer battery.

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