Method for dismantling a lithium battery

Abstract

The invention relates to a method for dismantling a lithium battery, the method comprising: - providing (S1) a lithium battery; - cutting (S2) the lithium battery by means of a jet of pressurised cutting liquid, the cutting liquid comprising at least one component that is in the liquid state; the cutting liquid being free of water; - separating (S4) constituents of the cut battery and the cutting liquid. The component comprises a first component in the liquid state for cutting the lithium battery, for example carbon dioxide. The component can comprise at least one second component chosen from among ethylene glycol, propylene glycol or a mixture thereof.

Description

METHOD FOR DISMANTLING A LITHIUM BATTERY

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

[0002] The electric mobility market is booming, resulting in a dramatic increase in the number of batteries in use. The number of batteries in use will grow with the significant increase in the vehicle fleet in the coming years. It appears that battery recycling will become a major issue from both an environmental and economic perspective.

[0003] When the battery is in a condition that is compatible with reuse, it will be possible to reintroduce it into a new cycle of use. On the other hand, when the battery is in a condition that is incompatible with its reuse, it will be necessary to recycle the battery, that is to say to dismantle it in order to separate the different components of the battery.

[0004] Multiple processes are known for recycling batteries, particularly for recycling low-capacity lithium-ion batteries such as those used to power a telephone, a laptop or portable power tools. Among the many processes for recycling batteries, documents US7,820,317 and EP1733451 illustrate processes used industrially in battery recycling.

[0005] The greater the electrical charge remaining in the battery, the greater the risks. To ensure safety, it is important to electrically and individually test the battery before recycling it. However, when the battery is defective, it is not always easy to perform the electrical test. The greater the battery capacity, the greater the risks associated with recycling, as the amount of stored electrical charge can be significant and the amount of lithium is increased.

[0006] Conventionally, battery recycling requires access to the internal components, which means disassembling the battery. Automotive batteries weigh between 180 and 400 kg, and each manufacturer has its own integration scheme. Some batteries are assembled with screws and nuts, while others are welded or glued. Due to the great inhomogeneity in battery design and shape, it is very difficult, if not impossible, to implement an automated disassembly strategy. Furthermore, in the event of an accident, the battery may be deformed, making it impossible or difficult to disassemble.

[0007] It is then necessary to resort to manual mechanical disassembly which is a risky operation because the quantity of lithium is very large with an electrical charge that can be significant. This risk is all the greater because when opening the battery, there may be an unintentional piercing of the battery with the emission of solvents and / or fluorinated compounds. Subject of the invention

[0008] An object of the invention is to provide a method for dismantling a lithium battery which is simple to implement and which reduces the risks associated with battery opening operations.

[0009] According to one aspect of the invention, there is provided a method for dismantling a lithium battery which comprises the following steps:- providing a lithium battery;- cutting the lithium battery by means of a jet of pressurized cutting fluid, the cutting fluid comprising at least one component which is in the liquid state; the cutting fluid being free of water;- separating constituents of the cut battery and the cutting fluid.

[0010] Advantageously, the component comprises at least one first component in the liquid state for cutting the lithium battery, the at least one first component being formed by at least one molecule which is in the gaseous state when the at least one molecule is at a temperature equal to 20°C and at a pressure equal to 1013hPa and in which the method further comprises a transformation of the first component from the liquid state to the gaseous state before separating the constituents of the cut battery and the cutting liquid.

[0011] According to a preferred embodiment of the invention, the component is only made up of at least one first component.

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

[0013] In an advantageous embodiment, the at least one first component comprises predominantly carbon dioxide by volume.

[0014] Preferably, the separation is carried out dry.

[0015] According to a preferred aspect of the invention, the method comprises, after cutting the lithium battery, recovery of at least one first component in the gaseous state and compression of the at least one first component to place it in the liquid state for cutting a new lithium battery.

[0016] Advantageously, the battery is introduced into a chamber filled with a first gas. The first component in the gaseous state is denser than the first gas.

[0017] In a particular configuration, the cutting fluid is free of liquid nitrogen.

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

[0019] Preferably, the liquid jet is a liquid jet at a pressure between 200 and 500 MPa.

[0020] According to one embodiment, the liquid jet comprises polyetheramines to neutralize battery acid.

[0021] In an advantageous development, the cutting fluid comprises, in addition to the component in the liquid state, abrasive particles chosen from silicon carbide and a copper slag which preferably has a fayalite base.

[0022] Preferably, a mass ratio between the component in the liquid state and the abrasive particles (m liquide / mparticles) is between 2 and 4.

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

[0024] Other advantages and characteristics will emerge more clearly from the following description of particular embodiments and implementations of the invention given as non-limiting examples and represented in the appended drawings, in which:

[0025] : schematically illustrates a block diagram of a method for dismantling a lithium battery according to the invention;

[0026] : schematically illustrates a cutting chamber equipped with a battery and a cutting fluid injection nozzle.

[0027] The method for dismantling a lithium battery illustrated in comprises a first step S1 of supplying the lithium battery followed by a step S2 of cutting the lithium battery using a pressurized liquid jet. The purpose of step S2 of cutting the lithium battery is to open the lithium battery in order to allow access to the internal components of the battery to separate the different components. Access to the battery components allows, for example, the separation of lithium from other constituents of the battery, for example polymer compounds, noble metals, iron or steel assembly parts. This also allows solvents to be extracted from the battery.

[0028] Following the cutting of the battery, the process has a step S3 which consists of separating the constituents of the cut battery and the cutting liquid.

[0029] As illustrated in, the cutting of the battery 1 is carried out in a cutting chamber 2. A nozzle 3 is supplied by a reservoir 4 which contains the liquid. High pressure supply means are configured to supply the nozzle 3 with high pressure liquid and provide a jet 5 of high pressure liquid capable of cutting the battery.

[0030] The battery cutting step S2 uses a high-pressure liquid jet. The liquid comprises at least one component that is in a liquid state. Depending on the embodiments, the liquid may comprise abrasive particles or be free of abrasive particles.

[0031] The liquid used for cutting the battery may contain a single component in the liquid state or it may contain a mixture of several components in the liquid state. The liquid is water-free. Water is a compound that will react with one or more components of the battery. This reaction can be exothermic, which leads to risks of burns or explosion. Water can also degrade one or more components of the battery. It is therefore particularly advantageous not to use water to cut the battery to avoid damaging the multiple components of the battery. Cutting the battery eliminates the need for manual mechanical opening. It is also advantageous to ensure that the cutting fluid is free of ionic liquid.

[0032] Particularly advantageously, the liquid used for cutting the battery only comprises liquid components which do not react with lithium and even more preferably than liquid components which do not react with the constituents of the battery. The component(s) of the cutting liquid are preferably inert with lithium and even more preferably inert with the other constituents of the battery.

[0033] In a particularly advantageous embodiment, the component comprises at least one first component in the liquid state for cutting the lithium battery. The at least one first component is formed by at least one molecule which is in the gaseous state when the at least one molecule is at a temperature equal to 20°C and at a pressure equal to 101325Pa.

[0034] In other words, during the cutting operation, the first component is in the liquid state, but the first component can also be in the gaseous state under temperature and pressure conditions that are not considered detrimental to the battery constituents. For example, the first component is chosen to be in the gaseous state under normal temperature and pressure conditions (0°C, 101325Pa). However, it is advantageous for the first component to be chosen to be in the gaseous state at a temperature equal to 20°C and a pressure equal to 101325Pa, which corresponds to non-traumatic working conditions for an operator.

[0035] The use of a component which can easily be in the gaseous state makes it possible, after a step S4 of phase change of the first component from the liquid phase to the solid phase, to facilitate the recovery of at least part of the cutting fluid.

[0036] In an even more advantageous embodiment, the liquid phase component is only made up of at least one first component. Thus, when the operator intervenes in the chamber which carries out the cutting of the battery to recover the constituents after the cutting operation, the operator can recover elements which are not wetted by the cutting liquid because the latter is completely transformed into gas.

[0037] In order to facilitate the separation between the cutting fluid and the battery, the dismantling process involves a transformation of the first liquid component so that the first liquid component changes to a gaseous state after cutting the lithium battery.

[0038] The use of a first component which may be in the gaseous state under temperature and pressure conditions such that the majority or all of the constituents of the battery are in the liquid or solid state makes it possible to facilitate the dissociation between the liquid component or the majority liquid component of the cutting fluid which has changed phase and the constituents of the battery.

[0039] When cutting the battery, the cutting fluid is ejected from the nozzle under temperature and pressure conditions that ensure that the first component is in the liquid state at the nozzle outlet and that it reaches the battery in the liquid state. Preferably, the cutting fluid is ejected from the nozzle at high pressure and possibly at low temperature to ensure that it remains in the liquid state. It is advantageous to eject a liquid whose temperature is between -56°C and -80°C at 1013hPa.

[0040] In a particular embodiment, the cutting of the battery is carried out in a chamber whose temperature and pressure conditions correspond to at least one first component in the gaseous state. In this way, the first liquid is ejected from the nozzle in the liquid state, it strikes the battery in the liquid state with sufficient energy to cut the battery. The heating of the cutting liquid during the cutting of the battery allows at least a portion of the first component to pass into the gaseous state. The first component which has passed into the gaseous state during the cutting advantageously remains in the gaseous state in the chamber. This configuration makes it possible to limit the thermal and mechanical stresses on the cutting chamber. Depending on the configurations, the first component in the liquid state which reaches the walls of the cutting chamber can remain in the liquid state or can pass into the gaseous state.

[0041] In this way, as the battery is cut, the first liquid component transforms at least partially into gas upon contact with the battery, which preferably makes it possible to partially or completely fill the atmosphere of the chamber with a gas which is inert with respect to the constituents of the battery.

[0042] Once the battery has been cut, a transformation step from the liquid state to the gaseous state of the first component is carried out, for example for the portion that has not heated up enough during the cutting of the battery. The transformation can be obtained with an increase in temperature and / or a decrease in pressure in the chamber. Preferably, the pressure in the chamber is reduced in order to balance with the pressure outside the chamber and which is preferably between 90000Pa and 110000Pa, preferably atmospheric pressure, approximately 101325Pa depending on the altitude and weather conditions. It is also possible to increase the temperature inside the chamber and it is preferable not to exceed 50°C.

[0043] Preferably, the cutting chamber is filled with a first gas, a pure gas or a gas mixture before starting the cutting operation and preferably when introducing the battery into the cutting chamber. It is particularly advantageous if the first component in the gaseous state is denser than the first gas in order to surround the battery parts resulting from the cutting.

[0044] Preferably, the at least one first component comprises carbon dioxide. Carbon dioxide does not interact with lithium so that it will not cause carbon degradation, for example, the combustion of lithium. The interaction of carbon dioxide with the other constituents of the battery is low or zero, which facilitates the recycling of the latter. Preferably, the at least one first component comprises mainly carbon dioxide by volume, or even the at least one first component comprises exclusively carbon dioxide. In an advantageous embodiment, the first component is chosen from carbon dioxide, argon and helium. Carbon dioxide is preferred because it is cheaper.

[0045] Preferably, the first component is free of nitrogen or any other molecule capable of forming liquid nitrogen under the conditions of application of the liquid jet. It has been observed that nitrogen can form very reactive compounds with lithium particles such as lithium azides (LiN3) and lithium nitrides (Li3N). Lithium azides decompose violently when the liquid phase is heated and can give rise to toxic compounds. The same is true for lithium nitrides.

[0046] Preferably, the method for dismantling a lithium battery comprises, after cutting the lithium battery, recovery of at least one first component in the gaseous state and compression of the at least one first component to place it in the liquid state in the reservoir for a new cutting cycle of a new lithium battery. Thus, the material used to cut the battery is passed into the gaseous state in order to be dissociated from the constituents of the battery and then is compressed to pass into the liquid state and be reused for a new battery, which reduces the consumption of the first component.

[0047] It is particularly advantageous to use a first component that is denser than air, for example carbon dioxide. During the transformation from the liquid phase to the gaseous phase, this allows the battery components to be bathed in an atmosphere that is less reactive than air towards them. The carbon dioxide pushes oxygen and other gases that can react with the lithium to the top of the chamber, which reduces the risks of reaction between the lithium and the gases present in the chamber atmosphere. This embodiment is particularly advantageous when the chamber atmosphere is not replaced before the cutting step, for example when the chamber atmosphere is air at the start of the liquid jet cutting operation. By "air" is meant a gas mixture that contains at least 75% nitrogen and 20% oxygen.

[0048] Preferably, the cutting of the lithium battery is carried out in a chamber, the chamber being devoid of oxygen before initiating the cutting. Preferably, the cutting of the lithium battery is carried out in a chamber, the chamber being devoid of nitrogen before initiating the cutting.

[0049] At the end of the liquid jet cutting step, the chamber is mostly filled in volume with the first component in the gaseous state.

[0050] The lithium battery dismantling process includes a step S3 of recovering the battery parts, the battery parts being dry after cutting the battery. Since the first component has been transformed into a gas, the battery components are immediately usable for the next recycling step. When the liquid component only contains the first component, the transformation of the first component from the liquid state to the gaseous state allows for dry sorting of the battery components. When the cutting fluid contains abrasive particles, there is dry sorting between the abrasive particles and the battery components.

[0051] In an advantageous embodiment, the component in the liquid state comprises at least one second component which is in the liquid state under normal temperature and pressure conditions and / or at 20°C and 101325Pa. Preferably, the second component has a boiling point greater than 120°C, advantageously greater than 150°C. The second component is intended to be predominantly or exclusively in the liquid state throughout the cutting step and until the recovery of the battery constituents.

[0052] It is also advantageous to choose a second component that has a low saturated vapor pressure, for example less than 50 Pa at 20°C. Of course, the second component has little or no reactivity with the battery constituents.

[0053] It is also advantageous to choose a second component which has an auto-ignition temperature above 300°C, more preferably above 350°C.

[0054] Depending on the configurations, the component comprises only the first component, only the second component or a mixture of the first component and the second component. Even more preferably, if the battery is cut simultaneously using the first component and the second component, the first component is sent by means of a first nozzle and the second component is sent by means of a second nozzle.

[0055] It is particularly advantageous to choose the second component from alkyl glycols. In an advantageous embodiment, the component comprises at least one second component chosen from ethylene glycol, propylene glycol or a mixture thereof. These components are particularly advantageous because they do not react with lithium, nor with the majority of the battery constituents. It is then possible to cut the battery without fear of deterioration of the lithium. The use of alkyl glycol is advantageous because it allows the absorption of traces of water present in the atmosphere, which reduces the risks of reaction between the traces of water and the lithium salts, which reduces the risks of formation of hydrofluoric acid.

[0056] Advantageously, to obtain rapid and efficient cutting of the battery and in particular of its external casing, it is preferable to have a liquid jet pressure which is greater than 5Mpa, more preferably greater than 15Mpa, even more preferably greater than 50Mpa. When the component is mainly formed by the first constituent, the liquid jet is preferably a liquid jet at a pressure of between 200 and 500MPa. It is also possible to use this pressure range for the second component.

[0057] In a preferred embodiment, the liquid jet comprises polyetheramines, for neutralizing battery acid. A possible polyetheramine for neutralizing acid is marketed by Huntsman International under the name Jeffamine®. The use of a polyetheramine is advantageous in combination with the first and / or second component. The use of polyetheramines is particularly advantageous when the battery comprises a lithium hexafluorophosphate salt. It is particularly advantageous to use a polyetheramines which has a saturated vapor pressure of less than 50 Pa at 20°C and a flash point temperature which is higher than the temperature of the second component, preferably higher than 110°C or even higher than 150°C.

[0058] The use of polyetheramines is particularly advantageous in combination with the second component chosen from alkyl glycols because the properties of polyetheramines do not degrade the performance of alkyl glycols.

[0059] In order to increase the cutting power of the liquid jet relative to the constituents of the battery, preferably relative to the external casing of the battery, it is advantageous for the liquid used to form the liquid jet to comprise, in addition to the component in the liquid state, abrasive particles. Advantageously, the abrasive particles are made of a material which does not react chemically with lithium and preferably which does not react chemically with the other constituents of the battery.

[0060] It is particularly advantageous if the abrasive particles are free of steel and / or garnet, as these materials can react with lithium. Garnet refers to a silicate group of type A3B2(SiO4)3, in which A is composed of calcium (Ca), iron (Fe), magnesium (Mg), and manganese (Mn), and B is aluminum (Al) and chromium (Cr) inclusions. Depending on the origin of the deposits, traces of beryllium (Be), molybdenum (Mo), cobalt (Co), nickel (Ni), Zn, cadmium (Cd), and arsenic (As) are detected.

[0061] Preferably, the abrasive particles are chosen from silicon carbide and copper slag and preferably based on fayalite.

[0062] It is particularly advantageous to use silicon carbide because silicon carbide is very stable in the pH range between 1 and 13 while having a high hardness which makes it suitable for cutting the battery without chemically degrading upon contact with the various constituents of the battery. Silicon carbide can be used in the α form which crystallizes in a hexagonal system or in its β form which crystallizes in a face-centered cubic system. These two forms are stable in the aforementioned temperature range. It also appears that these two forms are chemically stable in a temperature range from -100°C to +1000°C. Silicon carbide has great qualities for forming abrasive particles in a liquid jet cutting operation.

[0063] The abrasive particles may also be particles from a copper slag. The copper slag particles are obtained from the melting of copper ore. The particles have a mass content of iron oxide Fe2O3 greater than 40%, a mass content of silicon oxide SiO2 greater than 30%, a mass content of aluminum oxide Al2O3 less than 10% and a mass content of calcium oxide less than 10%, preferably less than 5%.

[0064] It is particularly advantageous that the abrasive particles contain copper trapped as a sulfide in an amorphous glassy matrix. This prevents the copper from leaching out in a soluble ionic form.

[0065] Advantageously, the abrasive particles comprise olivine particles and more preferably fayalite particles, i.e. Fe2SiO4 particles. Even more preferably, the abrasive particles comprise (Mg, Fe)2SiO4 type particles.

[0066] Like silicon carbide particles, copper slag particles have significant chemical stability over a pH range of 2 to 12 and good thermal stability between -100°C and +1000°C.

[0067] In an advantageous embodiment, a mass ratio between the component and the abrasive particles (m liquide / particles) is between 2 and 4, when the battery is cut by the liquid.

[0068] The process of dismantling a lithium battery is particularly advantageous when the lithium battery is a lithium-ion battery.

[0069] The process of dismantling a lithium battery is particularly advantageous when the lithium battery is a battery of an electric vehicle, for example an electric car.

Claims

Method for dismantling a lithium battery comprising the following steps:- providing (S1) a lithium battery;- cutting (S2) the lithium battery by means of a jet of pressurized cutting fluid, the cutting fluid comprising at least one component which is in the liquid state with at least a first component in the liquid state; the cutting fluid being free of water;- transforming the first component from the liquid state to the gaseous state before separating (S4) the constituents of the cut battery and the cutting fluid. Method for dismantling a lithium battery according to claim 1 wherein the at least one first component is formed by at least one molecule which is in the gaseous state when the at least one molecule is at a temperature equal to 20°C and at a pressure equal to 1013hPa. Method for dismantling a lithium battery according to claim 2 wherein the component consists solely of at least one first component. Method for dismantling a lithium battery according to one of claims 2 and 3 in which the at least one first component comprises carbon dioxide. Method for dismantling a lithium battery according to claim 4 in which the at least one first component comprises predominantly carbon dioxide by volume. Method for dismantling a lithium battery according to one of claims 1 to 5 in which the separation (S4) is carried out dry. Method for dismantling a lithium battery according to claim 6 comprising, after cutting the lithium battery, recovery of the at least one first component in the gaseous state and compression of the at least one first component to place it in the liquid state for cutting a new lithium battery. Method for dismantling a lithium battery according to one of claims 2 to 7 in which the battery is introduced into a chamber filled with a first gas and in which the first component in the gaseous state is denser than the first gas. Method for dismantling a lithium battery according to one of claims 1 to 8 in which the cutting fluid is free of liquid nitrogen. Method for dismantling a lithium battery according to one of claims 1 to 9, in which the component comprises at least one second component chosen from ethylene glycol, propylene glycol or a mixture thereof. Method for dismantling a lithium battery according to one of claims 1 to 10 in which the liquid jet is a liquid jet at a pressure of between 200 and 500 MPa. Method for dismantling a lithium battery according to one of claims 1 to 11 in which the liquid jet comprises polyetheramines to neutralize an acid of the battery. Method for dismantling a lithium battery according to one of claims 1 to 12 in which the cutting liquid comprises, in addition to the component in the liquid state, abrasive particles chosen from silicon carbide and a copper slag which preferably has a fayalite base. A method of dismantling a lithium battery according to claim 13 wherein a mass ratio between the component in the liquid state and the abrasive particles (m liquide / mparticles) is between 2 and 4. A method of dismantling 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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