Device, system and method for discharging batteries

Abstract

The present invention relates to a device, system and method for safely discharging batteries. The device comprises a chamber for containing batteries, inlets and outlets for inert gas, a control system, and a horizontal surface designed to receive at least one battery, which divides the chamber horizontally and forms a receptacle together with the base of the chamber, wherein the receptacle contains a plurality of micronised conductive particles.

Description

[0001]

[0002] DEVICE, SYSTEM AND PROCEDURE FOR BATTERY DISCHARGE

[0003] TECHNICAL SECTOR

[0004] The invention described herein provides a device, a system and a method for discharging batteries safely and quickly.

[0005] BACKGROUND OF THE INVENTION

[0006] The extraction and recovery of valuable metals from degraded lithium-ion batteries is considered an effective solution to mitigate the shortage of critical materials for battery manufacturing. However, spent batteries destined for recycling often retain a residual amount of usable energy. Simply dismantling and shredding these batteries directly could lead to hazardous situations inherent in the stored residual electrochemical energy. Therefore, it is essential to perform a controlled discharge pretreatment (deactivation) before dismantling and shredding spent batteries to ensure process safety and effective recovery of valuable materials.

[0007] The most commonly used discharge method in battery recycling plants is regenerative discharge, which involves connecting the battery pack terminals to equipment designed to reuse the energy supplied by the batteries during the discharge process. This same method can be applied non-regeneratively by connecting resistors to both terminals of the battery pack, closing the electrical circuit and allowing the dissipation of the residual energy contained in the battery.

[0008] There are cases where regenerative deactivation cannot be carried out due to the impossibility of connecting the discharge terminals to the battery pack (i.e., lack of knowledge of the battery communication protocol, defective battery, non-operational electronics, etc.). In this scenario, deactivation can be performed non-regeneratively by various methods, including electrochemical deactivation in brine baths, freezing in liquid nitrogen followed by grinding processes, and deactivation by puncture in controlled atmospheres.

[0009] Another alternative for battery deactivation is to subject it to a puncture test in an inert, low-temperature environment. However, this method is only suitable for small batches of spent lithium-ion batteries and is not appropriate for large-scale industrial processes. The puncture method poses the potential risk of inducing thermal escalation reactions that can lead to fires or explosions, emitting harmful gases.

[0010] One of these methods is immersion in saline solution for discharge, also known as electrochemical discharge in a conductive solution. This type of discharge presents risks associated with the generation of aqueous waste and emissions of volatile organic compounds and halogenated compounds (most notably hydrofluoric acid and / or hydrochloric acid) and requires wastewater treatment after electrochemical discharge in a conductive solution. Additionally, this method suffers from thermal runaway reactions induced by the sudden heating of the battery, induced by the rapid discharge process.

[0011] An alternative to brine bath discharge is solids-contact discharge. However, this method presents technical limitations on an industrial scale due to the difficulty of regulating the battery discharge rate due to contact with solids. As described above, rapid discharge is associated with a sudden increase in battery temperature, which could induce thermal runaway reactions, which are the source of waste and emissions. Similarly, at high discharge rates (resulting from a high discharge current), there is also a rebound effect in the resulting battery voltage once the conductive medium has been removed. This results in an increase in the resulting battery voltage once the discharge is complete, making it difficult to reach voltages close to zero volts under conditions where the discharge rate is not controllable or adaptable.

[0012] The present invention solves the problems posed by known battery discharge methods. The invention allows for a simple and low-cost process, avoids the generation of waste and emissions, is environmentally friendly, and enables safe and rapid discharge of used batteries.

[0013] EXPLANATION OF THE INVENTION

[0014] The present invention provides a device, a system and a method for discharging used batteries for subsequent recycling in a safe manner.

[0015] In its first aspect, the invention relates to a device for discharging batteries characterized in that it comprises a chamber configured to receive at least one battery, a door configured to access the interior of the chamber, at least one inert gas inlet to the chamber, at least one inert gas outlet to the chamber, a control system, a horizontal surface configured to receive at least one battery that horizontally divides the chamber and forms a receptacle together with the base of the chamber, and where the receptacle comprises inside a plurality of micronized conductive particles, where the separating surface allows the passage of the micronized conductive particles and where the inert gas inlet and outlet are configured to introduce a flow of inert gas into the chamber at a speed sufficient to fluidize the plurality of micronized conductive particles.

[0016] The device enables the micronized conductive particles, once they are in a fluid state, i.e., fluidized, to complete the circuit by establishing direct contact between the positive and negative poles of the battery. This contact guarantees an uninterrupted flow of electric current, in which the degree of fluidization of the particles (particle concentration for a given volume) allows the battery discharge rate to be adapted based on the resulting voltage and temperature of said battery. Additionally, the device of the invention prevents thermal runaway and the rebound effect in the resulting battery voltage once the conductive medium has been removed.

[0017] In its second aspect, the invention relates to the use of the device of the first aspect for discharging batteries.

[0018] In its third aspect, the invention relates to a system for discharging batteries using the device of the first aspect of the invention. In its fourth aspect, the invention relates to a battery discharge method comprising the following steps: a) generating an inert atmosphere inside a chamber according to the first aspect of the invention by means of an inert gas; b) defining a voltage value of the battery; c) introducing at least one partially charged battery into the chamber of the previous stage; d) introducing a flow of inert gas into the discharge chamber of the previous stage, where the flow of inert gas fluidizes the micronized conductive particles; e) keeping the battery in the chamber until its residual voltage is lower than the voltage value previously set by the user in step b); f) stopping the flow of inert gas; and g) removing the fully or partially discharged battery from the chamber.

[0019] BRIEF DESCRIPTION OF THE DRAWINGS

[0020] To complement the description being made and in order to help better understand the characteristics of the invention, a set of drawings is attached as an integral part of said description, in which the following has been represented for illustrative and non-limiting purposes:

[0021] Figure 1.- Diagram of the preferred embodiment of the battery discharge chamber of the invention.

[0022] Figure 2.- Diagram of the preferred embodiment of the battery discharge system of the invention.

[0023] List of references:

[0024] 10. Download device

[0025] 11. Horizontal surface

[0026] 12. Camera

[0027] 13. Conductive micronized particles

[0028] 14. Gate

[0029] 15. Micronized conductive particle repository A. Inert gas inlet

[0030] B. Inert gas outlet

[0031] 20, 22. Conveyor belts

[0032] 21. Gas compressor

[0033] 23. Battery entry pre-chamber

[0034] 24. Battery discharge device

[0035] 25. Heat exchanger

[0036] 26. Gas scrubber

[0037] 27. Gas filter system

[0038] 28. Temperature control loop

[0039] 29. Voltage control loop

[0040] PREFERRED EMBODIMENT OF THE INVENTION

[0041] The present invention provides a device, a system and a method for discharging used batteries for subsequent recycling in a safe manner.

[0042] In its first aspect, the invention relates to a device for discharging batteries characterized in that it comprises a chamber configured to receive at least one battery, a door configured to access the interior of the chamber, at least one inert gas inlet to the chamber, at least one inert gas outlet to the chamber, a control system, a horizontal surface configured to receive at least one battery that horizontally divides the chamber and forms a receptacle together with the base of the chamber, and where the receptacle comprises inside a plurality of micronized conductive particles, where the separating surface allows the passage of the micronized conductive particles and where the inert gas inlet and outlet are configured to introduce a flow of inert gas into the chamber at a speed sufficient to fluidize the plurality of micronized conductive particles.

[0043] The term "battery" refers to a device that supplies electrical energy obtained by direct transformation of chemical energy, provided with internal or external storage and consisting of one or more cells. The term "cell" refers to the basic functional unit of a battery composed of electrodes, electrolyte, container, terminals, and separators, and containing active materials whose reaction generates electrical energy. The term "battery module" refers to the set of cells connected to each other (in series and / or parallel), usually enclosed within an outer casing, and intended to be used independently or in combination with other modules. The term "battery pack" refers to a set of cells or modules connected in series and / or parallel to form a voltage and capacity value (in Ampere-hours) defined by the total number of cells connected in series and parallel, respectively.In the context of the present invention, the term “battery” encompasses its different variants such as “cell”, “battery module” or “battery pack”.

[0044] The term "fluidization" refers to the physical phenomenon that occurs when a quantity of a particulate solid substance (usually present in a containment vessel) is placed under appropriate conditions to cause a solid / fluid mixture to behave like a fluid. This can be achieved by introducing a pressurized fluid, such as an inert gas, through the particulate medium.

[0045] In a preferred embodiment of the device of the first aspect, the plurality of micronized conductive particles consists of a mixture of non-metallic particles and metallic particles. In a preferred embodiment of the device of the invention, the mixture of the non-metallic particles and metallic particles is in a ratio in the range of 5 to 1, preferably in a ratio of 2 to 1. In a preferred embodiment of the invention, the plurality of micronized conductive particles have an electrical resistivity between 1*10' 4 and 1,7*10' 8 Q cm.

[0046] The term “metallic particles” refers to particles composed of materials commonly classified as metallic components, for example, copper, aluminum, silver, etc. The term also includes particles composed of metallic alloys.

[0047] The term “non-metallic particles” refers to particles composed of non-metallic elements, for example, compounds such as graphite or graphene, salts and mixtures thereof, such as mica or silicon oxide, or elements such as silicon or germanium. In the preferred embodiment of the device of the invention, the non-metallic particles are selected from carbon, mica, graphite, graphite, calcium or silicon oxides, silicon, or mixtures thereof, and the metallic particles are selected from copper, aluminum, zinc, silver, nickel, or mixtures thereof. Additionally, the non-metallic particles may comprise a binder, for example, polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), styrene butadiene rubber (SBR), modified cellulose, or carbon black.In the most preferred embodiment of the invention, the non-metallic particles consist of graphite-PVDF, with PVDF being the binder. In the most preferred embodiment of the first aspect of the invention, the micronized conductive particles consist of a mixture of graphite-PVDF particles and copper particles.

[0048] In a preferred embodiment of the device of the invention, the plurality of micronized conductive particles have a particle size between 50 and 5000 microns analyzed by sieving, preferably between 200 and 1500 microns.

[0049] In the preferred embodiment of the device of the invention, the non-metallic micronized conductive particles have a particle size between 50 and 2000 microns and where the metallic micronized conductive particles have a particle size between 50 and 5000 microns analyzed by sieving, preferably the metallic micronized conductive particles have a particle size between 200 and 1000 microns and the non-metallic micronized conductive particles have a particle size between 200 and 1500 microns.

[0050] In another preferred embodiment of the device of the invention, the control system is configured to modulate the inlet speed of the inert gas flow between 0.5 and 30 m / s, preferably between 0.5 and 6 m / s.

[0051] In another preferred embodiment of the device of the invention, the ratio between the total volume of the battery to be discharged and the plurality of micronized conductive particles is between 1:0.5 and 1:5. In another preferred embodiment of the device of the invention, the inert gas is selected from nitrogen, argon or mixtures thereof, preferably the inert gas is nitrogen.

[0052] In the most preferred embodiment of the device of the invention, the control system comprises a temperature and voltage control loop. The temperature control loop limits the temperature inside the chamber to less than 35°C, and if the temperature is exceeded, it allows the control system to modify the inert gas flow to control the degree of porosity of the bed of conductive solid particles in a fluidized state and thus limit contact of the particles with the battery, thereby reducing the discharge rate and effectively containing the temperature increase inside the chamber. The voltage control loop determines the battery voltage during the discharge process. The temperature and voltage control loops comprise at least one temperature sensor and at least one voltage sensor. The sensors used are common sensors known in the state of the art.

[0053] The battery discharge chamber has a horizontal surface (11) configured to receive the battery located above the base of the chamber, this horizontal surface is permeable to micronized conductive particles and can be constituted, for example, by a perforated tray or a grid. This horizontal surface that horizontally divides the chamber allows the fluidized conductive particles to be deposited in the lower part of the discharge chamber, in the receptacle (15), once the flow of inert gas is stopped. The horizontal surface (11) together with the base of the chamber (12) forms a receptacle (15), this receptacle (15) allows the storage of micronized conductive particles.

[0054] In another preferred embodiment of the device of the invention, the chamber configured to receive a battery is a sealed chamber, preferably a sealed chamber with containment walls. In another preferred embodiment, the chamber additionally comprises an insulating external casing, preferably this insulator is a plastic material, such as polytetrafluoroethylene, commonly known as Teflon®. In its most preferred embodiment, the device for discharging batteries comprises a grille at the gas outlet, which is located in the upper part of the chamber. This grille prevents the entry of conductive micronized particles into the inert gas systems.

[0055] In its second aspect, the invention relates to the use of the device of the first aspect for discharging at least one battery. In a preferred embodiment, the second aspect relates to the use of the device of the first aspect for discharging at least one lithium-ion, sodium-ion, or lead-acid battery. Some of the batteries may be, for example, lithium-ion batteries with a nickel-cobalt-aluminum (NCA) cathode, lithium-iron phosphate (LiFP), lithium-cobalt-oxide (LCO), nickel-manganese-cobalt (NMC), or mixtures thereof.

[0056] In its third aspect, the invention relates to a system for discharging batteries comprising the device of the first aspect of the invention.

[0057] In the preferred embodiment of the system of the invention, the system has a pre-chamber (23) before the device that allows the introduction of at least one battery into the device of the invention without breaking the inert atmosphere.

[0058] In the preferred embodiment of the system of the invention, the system incorporates a heat exchanger (25) that receives the inert gases from the device (24). Next, the inert gas from the heat exchanger (25) passes through a gas cleaner (26) and, finally, is subjected to a filtration process in a gas filter (27). The gas cleaner (26) may consist, for example, of a liquid trap to adsorb any volatile organic compounds generated during the battery discharge process. The gas filtration may consist of one or more filters, for example, activated carbon or aluminosilicate filters. The gas cleaner (26) and the gas filter (27) may be adapted as deemed necessary by means of devices or methods known in the state of the art.

[0059] In the preferred embodiment of the system of the invention, the system has a temperature control loop (28) that allows monitoring the temperature inside the device (24) and a voltage loop (29) that allows monitoring the battery voltage, the evolution of the discharge process, as well as stopping the discharge once the voltage is reduced below a defined threshold.

[0060] In the preferred embodiment of the third aspect of the invention, the system comprises a gas compressor (21) configured to introduce the inert gases into the device (24) at the pressure necessary for fluidizing the particles. The inert gases are selected from nitrogen, argon or mixtures thereof, preferably the inert gas is nitrogen. The inert gases are introduced at a temperature between 0 and 45°C, preferably between 10-20°C.

[0061] In the preferred embodiment of the third aspect of the invention, a feed mechanism is used to introduce the used battery into the discharge device, preferably the system has a first conveyor belt to introduce the used batteries into the discharge device and a second conveyor belt to extract the discharged batteries from the device (24). In another embodiment, the first and second conveyor belts are replaced by a single conveyor belt (20) that performs both functions.

[0062] In its fourth aspect, the invention relates to a method for discharging batteries using the device of the first aspect of the invention.

[0063] The battery discharge method comprises the following steps: a) generating an inert atmosphere inside a chamber according to the first aspect of the invention by means of an inert gas; b) defining a voltage value of the battery; c) introducing at least one partially charged battery into the chamber of the previous step; d) introducing a flow of inert gas into the discharge chamber of the previous step, where the flow of inert gas fluidizes the micronized conductive particles; e) keeping the battery in the chamber until its residual voltage is lower than the voltage value previously set by the user in step b); f) stopping the flow of inert gas; and g) removing the fully or partially discharged battery from the chamber.

[0064] The method of the invention is suitable for discharging all types of batteries. In a preferred implementation of the battery discharge method, the battery or batteries to be discharged may be, for example, lithium-ion, sodium-ion, or lead-acid batteries. Preferably, they are lithium-ion batteries, for example, nickel-cobalt-aluminum (NCA), lithium-iron-phosphate (LiFP), lithium-cobalt-oxide (LCO), nickel-manganese-cobalt (NMC) batteries, or mixtures thereof. In another preferred embodiment of the method, multiple batteries are introduced into the discharge chamber for simultaneous discharge.

[0065] In another preferred embodiment of the battery discharge method, the inert gas is selected from nitrogen, argon, or mixtures thereof. In its most preferred embodiment, the inert gas is nitrogen. Implementing the discharge method in an inert atmosphere is highly safe, as it effectively prevents the possibility of explosions or fires in the batteries. This ensures a controlled environment that minimizes the risks associated with handling and discharging all types of batteries.

[0066] The voltage value selected in step b) will vary depending on the type of battery being discharged, i.e., whether the battery is being discharged as battery packs, modules, or cells. The chemical nature of the battery will also influence the voltage selection; for example, it will vary depending on whether the battery being discharged is a lead, sodium, or lithium battery. The voltage value per cell selected in step b) is preferably between 0.5 and 3.5 V.

[0067] In a preferred embodiment of the battery discharge method, the battery is kept in the discharge chamber until its residual voltage is lower than the voltage value previously selected in step b).

[0068] In a preferred embodiment of the battery discharge method, the inlet velocity of the inert gas flow is between 0.5 and 30 m / s. In the most preferred embodiment, the inlet velocity of the inert gas flow is between 0.5 and 6 m / s.

[0069] In a preferred embodiment of the battery discharge method, the porosity of the fluidized bed of conductive solid particles is between 0.5 and 0.95. In the most preferred embodiment, the porosity of the fluidized bed of conductive solid particles is between 0.7 and 0.9. The porosity of the fluidized bed of conductive solid particles is determined from the ratio of the volume of the void spaces (pores) between the solid particles to the total chamber volume.

[0070] In a preferred embodiment of the battery discharge method, step d) during which the battery is kept in the discharge chamber lasts less than 24 hours, preferably between 10 minutes and 24 hours. In the most preferred embodiment, step d) lasts between 30 minutes and 3 hours.

[0071] Additionally, the battery discharge procedure incorporates a stage prior to stage f) for the recovery of conductive micronized particles. This particle recovery stage comprises the reversal of the direction of the inert gas flow to transport the mixture of solid particles from the discharge chamber to the repository (15). For example, the reversal of the inert gas flow is executed by opening inlet B and closing inlet A as well as the valve that leads to the gas treatment section (25, 26).

Claims

CLAIMS 1 . Device for discharging batteries (10) characterized in that it comprises a chamber (12) configured for receiving at least one battery, a door (14) configured to access the interior of the chamber, at least one inert gas inlet (A) to the chamber, at least one inert gas outlet (B) to the chamber, a control system (28,29), a horizontal surface (11) configured for receiving at least one battery that horizontally divides the chamber (12) and together with the base of the chamber (12) forms a receptacle (15), and where the receptacle (15) comprises inside it a plurality of micronized conductive particles (13), where the separating surface (11) allows the passage of the micronized conductive particles (13) and where the inert gas inlet (A) and outlet (B) are configured to introduce a flow of inert gas into the chamber at a speed sufficient to fluidize the plurality of micronized conductive particles.

2. The device according to the preceding claim wherein the plurality of micronized conductive particles (13) consist of a mixture of non-metallic particles and metallic particles.

3. The device according to the preceding claim wherein the non-metallic particles are selected from carbon, mica, graphite, silicon or mixtures thereof, and the metallic particles are selected from copper, aluminum, zinc, silver, nickel or mixtures thereof.

4. The device according to any of the preceding claims wherein the plurality of micronized conductive particles have a particle size between 50 and 5000 microns analyzed by sieving, preferably between 200 and 1500 microns.

5. The device according to any of the preceding claims wherein the non-metallic micronized conductive particles have a particle size between 50 and 2000 microns and where the metallic micronized conductive particles They have a particle size between 50 and 5000 microns analyzed by sieving, preferably the metallic micronized conductive particles have a particle size between 200 and 1000 microns and the non-metallic micronized conductive particles have a particle size between 200 and 1500 microns.

6. The device according to any of the preceding claims wherein the control system is configured to modulate the inlet velocity of the inert gas flow between 0.5 and 30 m / s, preferably between 0.5 and 6 m / s.

7. The device according to any of the preceding claims, wherein the plurality of conductive particles are in a proportion in relation to the total volume of the battery to be discharged, where said proportion is in the range of 1:0.5 to 1:5, defined as the ratio between the total volume of the battery to be discharged and the volume of the particles.

8. The device according to any of the claims wherein the inert gas is nitrogen, argon or mixtures thereof, preferably the inert gas is nitrogen.

9. The device according to any of the preceding claims, wherein the control system comprises a temperature and voltage control loop.

10. The device according to any of the preceding claims, wherein the horizontal surface (11) is a perforated tray or grid.

11. The device according to any of the preceding claims, wherein the chamber configured for receiving a battery is a sealed chamber, preferably the chamber is a sealed chamber having containment walls.

12. Use of the device according to any preceding claim for discharging batteries.

13. Battery discharge procedure comprising the following steps: a) generating an inert atmosphere inside a chamber according to any of claims 1 to 11; b) defining a battery voltage value; c) introducing at least one partially charged battery into the chamber of the previous stage; d) introducing a flow of inert gas into the discharge chamber of the previous stage, where the flow of inert gas fluidizes the micronized conductive particles; e) keeping the battery in the chamber until its residual voltage is lower than the voltage value previously set by the user in step b); f) stopping the flow of inert gas; and g) removing the fully or partially discharged battery from the chamber.

14. The battery discharge method according to the preceding claim, wherein the at least one battery is selected from lithium-ion, sodium-ion or lead batteries, preferably lithium-ion batteries, more preferably lithium-ion batteries with a Nickel-Cobalt-Aluminum (NCA) cathode, Lithium-Iron Phosphate (LiFP), Lithium-Cobalt-Oxide (LCO), Nickel-Manganese-Cobalt (NMC) or mixtures thereof.

15. The battery discharge method according to any of claims 13 to 14, wherein the inlet velocity of the inert gas flow is between 0.5 and 30 m / s, preferably between 0.5 and 6 m / s.

16. The battery discharge method according to any of claims 13 to 15, wherein the porosity of the bed of conductive solid particles in a fluidized state is between 0.5 and 0.95, preferably between 0.7 and 0.

9.

17. The battery discharge method according to any of claims 13 to 16, wherein step d) has a duration of less than 24 hours.

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