Method for disassembling a lithium battery

Abstract

A method for disassembling a lithium battery comprises: - a step (S1) of preparing a lithium battery; - a step (S2) of cutting the lithium battery by a jet of a cutting fluid under pressure, wherein the cutting fluid comprises at least one component in a liquid state and the cutting fluid does not contain water; - a step (S4) of separating the components of the cut battery from the cutting fluid. The component comprises a first component in a liquid state for cutting the lithium battery, for example carbon dioxide. The component can comprise at least a second component selected from ethylene glycol, propylene glycol, or a mixture of ethylene glycol and propylene glycol.

Description

Technical Field

[0001] The present invention relates to a method for disassembling a lithium battery.

Background Art

[0002] The electric mobility market is booming, and the number of batteries in use is increasing remarkably. The number of batteries in use will increase in the coming years along with a significant increase in the total number of vehicles. It is clear that battery recycling will become a major issue both environmentally and economically.

[0003] When the battery shows a state compatible with reuse, the battery can be reinserted into a new usage cycle. On the other hand, when the battery is in a state incompatible with reuse, the battery needs to be recycled, that is, disassembled to disassemble various components of the battery.

[0004] To recycle batteries, various methods are known, especially for recycling low-capacity lithium-ion batteries used, for example, to power mobile phones, laptops, or portable power tools. Among the numerous methods designed to recycle batteries, in particular, US Patent No. 7,820,317 and EP1,733,451 exemplify methods used to perform battery recycling industrially.

[0005] The higher the charge remaining in the battery, the greater the risk. To be able to work safely, it is important to electrically test the battery individually before recycling. However, when the battery has a defect, it is not always easy to perform an electrical test. As the battery capacity increases, the amount of accumulated charge may increase, and the amount of lithium also increases, so the risk associated with recycling increases.

[0006] In the conventional method, battery recycling requires accessing the internal components, so the battery needs to be disassembled. Automotive batteries weigh 180 - 400 kg, and each manufacturer has its own integrated system. Some batteries are assembled using nuts and bolts, while others are welded or joined. Given the very high degree of non-uniformity in battery design and form, it is very difficult, if not impossible, to devise and implement an automated strategy for disassembling the battery. Furthermore, in the event of an accident, the battery may be deformed, making disassembly impossible or difficult.

[0007] In that case, a shift in policy to mechanical manual disassembly is necessary, which is a risky operation as a significant amount of lithium may carry a charge that cannot be ignored. This risk is even greater as there is a possibility that the battery may accidentally develop holes when opened, releasing solvents and / or fluorine compounds.

Summary of the Invention

Problems to be Solved by the Invention

[0008] One object of the present invention is to provide a method for disassembling a lithium battery that is simple to implement and reduces the risks associated with battery opening operations.

Means for Solving the Problems

[0009] According to one aspect of the present invention, there is provided a method for disassembling a lithium battery, comprising: - providing a lithium battery; - cutting the lithium battery by a jet of cutting fluid under pressure, wherein the cutting fluid comprises at least one component in a liquid state and the cutting fluid does not contain water; - separating the components of the cut battery from the cutting fluid. A method is proposed that includes these steps.

[0010] Advantageously, the component comprises at least a first component in a liquid state for disconnecting a lithium battery, and the at least first component is formed by at least one molecule that becomes gaseous when at a temperature equal to 20 °C and under a pressure equal to 1013 hPa. The method further comprises a conversion of the first component from a liquid state to a gaseous state before separating the components of the disconnected battery from the cutting fluid.

[0011] According to a preferred embodiment of the invention, the component consists of at least the first component only.

[0012] Preferably, the at least first component comprises carbon dioxide.

[0013] In an advantageous embodiment, the at least first component mainly comprises carbon dioxide in the volume.

[0014] Preferably, the separation is performed dry.

[0015] According to a preferred feature of the invention, the method comprises recovering at least the first component in a gaseous state after cutting the lithium battery, and compressing at least the first component to a liquid state for cutting a new lithium battery.

[0016] Advantageously, the battery is inserted into a chamber filled with a first gas. The first component in a gaseous state has a higher density than the first gas.

[0017] In a specific configuration, the cutting fluid does not contain liquid nitrogen.

[0018] In an advantageous development, the component comprises at least a second component selected from ethylene glycol, propylene glycol, or a mixture of ethylene glycol and propylene glycol.

[0019] Preferably, the liquid jet is a liquid jet with a pressure of 200 to 500 MPa.

[0020] According to one embodiment, the liquid jet comprises a polyetheramine for neutralizing the acid of the battery.

[0021] In an advantageous development, the cutting fluid comprises abrasive particles selected from silicon carbide and preferably copper slag having a firelight base, in addition to the components in the liquid state.

[0022] Preferably, the mass ratio (m liquid / m particles ) between the components in the liquid state and the abrasive particles is 2 to 4.

[0023] In another advantageous development, the lithium battery is a lithium-ion battery.

[0024] Other advantages and features are given for illustrative purposes only and will become more clearly apparent from the following description of specific embodiments and embodiments of the invention represented in the accompanying drawings.

Brief Description of the Drawings

[0025]

Figure 1

Figure 2

Modes for Carrying Out the Invention

[0026] The method of disassembling the lithium battery shown in FIG. 1 comprises a first step S1 of preparing the lithium battery, followed by a step S2 of cutting the lithium battery by means of a liquid jet under pressure. The purpose of step S2 of cutting the lithium battery is to open the lithium battery to access the internal components of the battery and separate the different components. By accessing the components of the battery, it becomes possible, for example, to separate lithium from other components of the battery, such as polymer compounds, precious metals, and iron or steel assemblies. This also makes it possible to extract the solvent from the battery.

[0027] The method comprises a step S4 consisting of separating the components of the cut battery from the cutting liquid following the cutting of the battery.

[0028] As shown in FIG. 2, the cutting of the battery 1 is carried out within the cutting chamber 2. The nozzle 3 is supplied via a tank 4 containing the liquid. The high-pressure delivery means is configured to supply high-pressure liquid to the nozzle 3 and provide a jet 5 of high-pressure liquid capable of cutting the battery.

[0029] Step S2 of cutting the battery uses a high-pressure liquid jet. The liquid comprises at least one component in a liquid state. Depending on the embodiment, the liquid may or may not contain abrasive particles.

[0030] The liquid used to cut the battery can comprise a single component in a liquid state or can comprise a mixture of several components in a liquid state. The liquid is water-free. Water is a compound that reacts with one or more components of the battery. This reaction is exothermic and may pose a risk of combustion or explosion. Also, water can damage one or more components of the battery. Therefore, in order to avoid damaging the various components of the battery, it is particularly advantageous not to use water to cut the battery. By cutting the battery, it is no longer necessary to use a mechanical manual release. It is also advantageous to ensure that the cutting fluid does not contain an ionic liquid.

[0031] In a particularly advantageous way, the liquid used to cut the battery comprises only liquid components that do not react with lithium, and in a more preferred way, it comprises only liquid components that do not react with the components of the battery. One or more components of the cutting fluid are preferably inert with respect to lithium and more preferably inert with respect to the other components of the battery.

[0032] In a particularly advantageous embodiment, the component comprises at least a first component in a liquid state for cutting a lithium battery. The at least first component is formed by at least one molecule that becomes gaseous when at a temperature equal to 20 °C and a pressure equal to 101,325 Pa.

[0033] In other words, when the cutting operation is performed, the first component is in a liquid state, but the first component may be in a gaseous state under temperature and pressure conditions that are not considered harmful to the components of the battery. For example, the first component is selected to be gaseous under standard temperature and pressure conditions (0 °C, 101,325 Pa). However, it is advantageous that the first component is selected to be gaseous at a temperature equal to 20 °C and a pressure equal to 101,325 Pa, which corresponds to working conditions that are not uncomfortable for the operator.

[0034] When using a component that is likely to be in a gaseous state, after step S3 of phase-changing the first component from a liquid phase to a solid phase, it becomes easier to recover at least a part of the cutting fluid.

[0035] In an even more advantageous embodiment, the liquid-phase component is composed of at least only the first component. By doing so, when an operator performs a battery cutting operation in the chamber and recovers the components after the cutting operation, since the cutting fluid is completely converted into a gas, the operator can recover the elements not wetted by the cutting fluid.

[0036] To facilitate the separation between the cutting fluid and the battery, the disassembly method includes the conversion of the first liquid component, whereby after the lithium battery is cut, the first liquid component changes to a gaseous state.

[0037] When using a first component that can be in a gaseous state under temperature and pressure conditions such that most or all of the components of the battery are in a liquid state or a solid state, the decomposition between the liquid component or most of the liquid components of the phase-changed cutting fluid and the components of the battery becomes easier.

[0038] When the battery is cut, the cutting fluid is ejected from the nozzle under temperature and pressure conditions that ensure that the first component is in a liquid state at the outlet from the nozzle and reaches the battery in a liquid state. In a preferred manner, to ensure that the cutting fluid is kept in a liquid state, the cutting fluid is ejected from the nozzle at a high pressure and, in some cases, at a low temperature. It is advantageous to eject a liquid at a temperature composed between -56 °C and -80 °C at 1,013 hPa.

[0039] In certain embodiments, the cutting of the battery is performed within the chamber under temperature and pressure conditions corresponding to at least the first component being in a gaseous state. By doing so, the first liquid is ejected from the nozzle in a liquid state and impinges on the battery in a liquid state with sufficient energy to cut the battery. When heating the cutting fluid during battery cutting, at least a portion of the first component can be changed to a gaseous state. The first component that changes to a gaseous state when cutting is performed preferably remains in a gaseous state within the chamber. This configuration means that the thermal and mechanical stresses on the cutting chamber are limited. The first component in a liquid state reaching the wall of the cutting chamber can, depending on the configuration, remain in a liquid state or change to a gaseous state.

[0040] By doing so, as the battery is cut, the first liquid component is gradually at least partially converted to a gas that contacts the battery, thereby preferably at least partially or fully filling the atmosphere of the chamber with a gas inert to the components of the battery.

[0041] When the battery is cut, for example, for portions that were not sufficiently heated when the battery was cut, the step of converting the first component from a liquid state to a gaseous state is performed. The conversion can be achieved by increasing the temperature and / or decreasing the pressure within the chamber. In a preferred manner, the pressure within the chamber is decreased to balance, depending on altitude and weather conditions, preferably with an external pressure of the chamber of 90,000 Pa to 110,000 Pa, preferably with an atmospheric pressure of about 101,325 Pa. It is also possible to increase the temperature within the chamber, preferably not exceeding 50°C.

[0042] In a preferred manner, before starting the cutting operation, preferably when the battery is placed within the cutting chamber, the cutting chamber is filled with a first gas, a pure gas, or a gas mixture. It is particularly advantageous for the first component in a gaseous state to have a higher density than the first gas in order to surround the parts of the battery resulting from the cutting operation.

[0043] In a preferred manner, at least the first component comprises carbon dioxide. Since carbon dioxide does not interact with lithium, degradation of carbon, such as combustion of lithium, does not occur. The interaction between carbon dioxide and other components of the battery is weak or non-existent, thereby facilitating battery recycling. Preferably, at least the first component mainly comprises carbon dioxide in volume, or at least the first component comprises only carbon dioxide. In an advantageous embodiment, the first component is selected from carbon dioxide, argon, and helium. Carbon dioxide is preferred because it is less expensive.

[0044] In a preferred manner, the first component does not contain dinitrogen or other molecules that can form liquid nitrogen under the application conditions of the liquid jet. It has been observed that nitrogen can form highly reactive compounds with lithium particles, such as lithium azide (LiN3) and lithium nitride (Li3N). Lithium azide can decompose violently during heating of the liquid phase and may produce toxic compounds. The same is true for lithium nitride.

[0045] In a preferred manner, the method of disassembling a lithium battery comprises recovering at least the first component in a gaseous state and compressing at least the first component to a liquid state in a tank for a new cutting cycle of a new lithium battery. Thus, the material used for cutting the battery is converted to a gaseous state, decomposed from the battery components, then compressed to a liquid state, and reused in a new battery, thereby reducing the consumption of the first component.

[0046] It is particularly advantageous to use a first component that is denser than air, for example carbon dioxide. When the conversion from the liquid phase to the gas phase occurs, this makes it possible to immerse the components of the battery in an atmosphere that is less reactive than air compared to air. Carbon dioxide pushes oxygen and other gases capable of reacting with lithium to the upper part of the chamber, thus reducing the risk of reaction between lithium and the gases present in the atmosphere of the chamber. This embodiment is particularly advantageous when the atmosphere of the chamber does not change before the cutting step, for example when the atmosphere of the chamber is air at the start of the cutting operation by a liquid jet. "Air" means a gas mixture containing at least 75% nitrogen and 20% oxygen.

[0047] Preferably, the cutting of the lithium battery is carried out in a chamber and the chamber does not contain oxygen before starting the cutting operation. Preferably, the cutting of the lithium battery is carried out in a chamber and the chamber does not contain nitrogen before starting the cutting operation.

[0048] At the end of the cutting step by a liquid jet, the chamber is mainly filled with a first component in the gaseous state.

[0049] The method of disassembling a lithium battery comprises a step S3 of recovering the components of the battery, and the components of the battery are dried after the battery is cut and opened. Since the first component is in the gaseous state, the components of the battery are immediately available for the next recycling step. If the liquid component comprises only the first component, by converting the first component from the liquid state to the gaseous state, dry sorting of the components of the battery becomes possible. If the cutting fluid contains abrasive particles, there is a dry sorting between the abrasive particles and the components of the battery.

[0050] In advantageous embodiments, the component in the liquid state comprises at least a second component that is in the liquid state under standard temperature and pressure conditions and / or at 20 °C and 101,325 Pa. Preferably, the boiling point of the second component is higher than 120 °C, advantageously higher than 150 °C. The second component is designed to be mainly or exclusively in the liquid state until the battery components are recovered throughout the cutting step.

[0051] It is also advantageous to select a second component that exhibits a low saturation vapor pressure of less than 50 Pa, for example, at 20 °C. The second component, of course, has low or no reactivity with the battery components.

[0052] It is also advantageous to select a second component with a self-ignition temperature higher than 300 °C, more preferably higher than 350 °C.

[0053] Depending on the configuration, the component comprises only the first component, only the second component, or a mixture of the first and second components. In a more preferred way, when the battery is cut simultaneously by the first and second components, the first component is delivered by the first nozzle and the second component is delivered by the second nozzle.

[0054] It is particularly advantageous to select the second component from alkyl glycols. In advantageous embodiments, the component comprises at least a second component selected from ethylene glycol, propylene glycol, or a mixture of ethylene glycol and propylene glycol. These components are particularly attractive because they do not react with lithium or most of the battery components. In this case, it is possible to cut the battery without the risk of damaging the lithium. The use of alkyl glycols is attractive because they can reduce the trace amount of water present in the atmosphere, thereby reducing the risk of reaction between the trace amount of water and the lithium salt, and thus reducing the risk of formation of hydrofluoric acid.

[0055] In an advantageous manner, in order to obtain a rapid and efficient cutting of the battery, in particular of its outer casing, it is preferable to have a liquid jet pressure greater than 5 MPa, more preferably greater than 15 MPa, even more preferably greater than 50 MPa. When the component is mainly formed by the first component, the liquid jet is preferably a liquid jet with a pressure of 200 - 500 MPa. It is also possible to use this pressure range for the second component.

[0056] In a preferred embodiment, the liquid jet comprises a polyetheramine for neutralizing the acid of the battery. Possible polyetheramines for neutralizing the acid are sold under the trade name Jeffamine® by Huntsman International Corporation. It is advantageous to use the polyetheramine in combination with the first component and / or the second component. The use of polyetheramine is particularly advantageous when the battery comprises a lithium hexafluorophosphate salt. It is particularly advantageous to use a polyetheramine having a saturated vapor pressure of less than 50 Pa at 20°C and a flash point temperature higher than the temperature of the second component, preferably higher than 110°C, or even higher than 150°C.

[0057] Since the properties of the polyetheramine do not impair the performance of the alkyl glycol, it is particularly advantageous to use the polyetheramine in combination with a second component selected from alkyl glycols.

[0058] In order to increase the cutting force of the liquid jet on the battery component, preferably the outer casing of the battery, it is advantageous for the liquid used to form the liquid jet to comprise abrasive particles in addition to the component in the liquid state. Advantageously, the abrasive particles are made of a material that does not chemically react with lithium, preferably a material that does not chemically react with the other components of the battery.

[0059] Since steel and / or garnet may react with lithium, it is particularly advantageous for the abrasive particles not to contain these materials. Garnet means a group of silicates of the A3B2(SiO4)3 type, where A consists of calcium (Ca), iron (Fe), magnesium (Mg), and manganese (Mn), and B relates to aluminum (Al) or chromium (Cr)-based inclusions. Depending on the origin of the sediment, trace amounts of beryllium (Be), molybdenum (Mo), cobalt (Co), nickel (Ni), zinc (Zn), cadmium (Cd), and arsenic (As) are detected.

[0060] In a preferred manner, the abrasive particles are selected from silicon carbide and preferably copper slag having a fayalite base.

[0061] Silicon carbide is very stable in the pH range of 1 to 13 and is particularly advantageous to use because it is hard enough to cut the battery without being chemically damaged even when in contact with various components of the battery. Silicon carbide can be used in the α-form that crystallizes in the hexagonal system or the β-form that crystallizes in the face-centered cubic system. These two forms are stable in the temperature range described above. It is also clear that these two forms are chemically stable in the temperature range of -100 °C to +1,000 °C. Silicon carbide exhibits excellent properties for forming abrasive particles in liquid jet cutting operations.

[0062] The abrasive particles can also be particles derived from copper slag. Copper slag particles result from the refining of copper minerals. The particles comprise iron oxide Fe2O3 with a mass fraction exceeding 40%, silicon oxide SiO2 with a mass fraction exceeding 30%, aluminum oxide Al2O3 with a mass fraction less than 10%, and calcium oxide with a mass fraction less than 10%, preferably less than 5%.

[0063] It is particularly advantageous for the abrasive particles to comprise copper trapped in the form of sulfide in an amorphous glassy matrix. This prevents copper from leaching out in the form of soluble ions.

[0064] Advantageously, the abrasive particles comprise olivine particles and more preferably fayalite particles, i.e., particles of Fe2SiO4. Even more preferably, the abrasive particles comprise (Mg, Fe)2SiO4 type particles.

[0065] Similar to silicon carbide particles, copper slag particles have high chemical stability over a pH range of 2 to 12 and good thermal stability at -100°C to +1,000°C.

[0066] In an advantageous embodiment, when the battery is cut by a liquid, the mass ratio (m liquid / m particles ) between the component and the abrasive particles is 2 to 4.

[0067] The method for disassembling a lithium battery is particularly advantageous when the lithium battery is a lithium ion battery.

[0068] The method for disassembling a lithium battery is particularly advantageous when the lithium battery is a battery of an electric vehicle, such as an electric motor vehicle.

Claims

1. A method for disassembling a lithium battery, comprising: - a step (S1) of preparing a lithium battery; - a step (S2) of cutting the lithium battery by means of a jet of a cutting fluid under pressure, wherein the cutting fluid comprises at least one component in a liquid state, at least a first component is in a liquid state, and the cutting fluid does not contain water; - a step of converting the first component from a liquid state to a gaseous state before a step (S4) of separating the components of the cut battery from the cutting fluid A method for disassembling a lithium battery.

2. The method for disassembling a lithium battery according to claim 1, wherein the at least first component is formed by at least one molecule that is in a gaseous state when at a temperature equal to 20 °C and under a pressure equal to 1013 hPa.

3. The method for disassembling a lithium battery according to claim 2, wherein the component consists only of the at least first component.

4. The method for disassembling a lithium battery according to any one of claims 2 and 3, wherein the at least first component comprises carbon dioxide.

5. The method for disassembling a lithium battery according to claim 4, wherein the at least first component mainly comprises carbon dioxide in volume.

6. The method for disassembling a lithium battery according to any one of claims 1 to 5, wherein the separating step (S4) is performed in a dry manner.

7. The method for disassembling a lithium battery according to claim 6, comprising recovering the at least first component in a gaseous state after the lithium battery is cut, and compressing the at least first component to a liquid state for cutting a new lithium battery.

8. The method for disassembling a lithium battery according to any one of claims 2 to 7, wherein the battery is inserted into a chamber filled with a first gas, and the first component in a gaseous state has a higher density than the first gas.

9. The method for disassembling a lithium battery according to any one of claims 1 to 8, wherein the cutting fluid does not contain liquid nitrogen.

10. The method for disassembling a lithium battery according to any one of claims 1 to 9, wherein the component comprises at least a second component selected from ethylene glycol, propylene glycol, or a mixture of ethylene glycol and propylene glycol.

11. The method for disassembling a lithium battery according to any one of claims 1 to 10, wherein the liquid jet is a liquid jet having a pressure of 200 to 500 MPa.

12. The method for disassembling a lithium battery according to any one of claims 1 to 11, wherein the liquid jet comprises a polyetheramine for neutralizing the acid of the battery.

13. The method for disassembling a lithium battery according to any one of claims 1 to 12, wherein the cutting fluid comprises abrasive particles selected from silicon carbide and copper slag having preferably a firelight base, in addition to the components in a liquid state.

14. The mass ratio (m ｌｉｑｕｉｄ / m ｐａｒｔｉｃｌｅｓ ) between the component in the liquid state and the abrasive particles is 2 to 4, the method for disassembling a lithium battery according to claim 13.

15. The method for disassembling a lithium battery according to any one of claims 1 to 14, wherein the lithium battery is a lithium-ion battery.

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