Battery processing method and battery processing system

Abstract

This invention provides a battery processing method and a battery processing system that can efficiently recover lithium from lithium-ion batteries. [Solution] A battery processing method for processing a lithium-ion battery comprising a positive electrode material and a negative electrode material, wherein the positive electrode material and the negative electrode material are stacked in a stacking direction, and gas is present inside, the method comprising: a gas extrusion step of pushing the gas toward the peripheral edge of the lithium-ion battery in a plane perpendicular to the stacking direction; and a cooling and charging step of charging the lithium-ion battery while cooling it to deposit lithium on the negative electrode material.

Description

Technical Field

[0001] The present invention relates to a battery processing method and a battery processing system.

Background Art

[0002] In recent years, the adoption of lithium-ion batteries as in-vehicle batteries for electric vehicles such as electric vehicles and hybrid vehicles has been expanding. Lithium-ion batteries contain valuable substances containing lithium. It is required to recycle resources by recycling valuable substances from used lithium-ion batteries.

[0003] Patent Document 1 discloses a method of recovering lithium from a positive electrode material after increasing the amount of lithium contained in the positive electrode material by discharging a used lithium-ion battery.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] The positive electrode material is generally composed of forming a positive electrode active material on a current collector foil such as aluminum. The positive electrode active material contains valuable substances such as nickel, manganese, and cobalt in the case of, for example, a ternary system (NMC). In order to recover valuable substances from the positive electrode active material, the positive electrode material is baked with a reducing agent, pulverized, and then black mass containing the positive electrode active material is sorted. Next, manganese, cobalt, and nickel are sequentially extracted by stepwise solvent extraction of the black mass, and finally lithium is extracted. Therefore, it has been particularly laborious to recover lithium.

[0006] The object of this invention is to provide a battery processing method and a battery processing system that can efficiently recover lithium from lithium-ion batteries. [Means for solving the problem]

[0007] The present invention A battery processing method for a lithium-ion battery comprising a positive electrode material and a negative electrode material, wherein the positive electrode material and the negative electrode material are stacked in a stacking direction, and gas is present inside the battery, A gas extrusion step in which the gas is pushed toward the peripheral edge of the lithium-ion battery in a plane perpendicular to the stacking direction, A cooling and charging process in which the lithium-ion battery is charged while being cooled, thereby depositing lithium on the negative electrode material. A battery processing method, including the following. [Effects of the Invention]

[0008] According to the present invention, lithium can be efficiently recovered from the negative electrode of a lithium-ion battery. [Brief explanation of the drawing]

[0009] [Figure 1] A schematic block diagram illustrating the reuse system according to the first embodiment. [Figure 2] A perspective view showing the schematic configuration of a lithium-ion battery. [Figure 3] A cross-sectional view showing the general configuration of a battery cell. [Figure 4] A flowchart illustrating the general process of reusing lithium-ion batteries. [Figure 5A] A schematic diagram illustrating an example of a gas extrusion apparatus according to the first embodiment. [Figure 5B] A schematic diagram illustrating an example of a gas extrusion apparatus according to the first embodiment. [Figure 5C] A schematic diagram illustrating an example of a gas extrusion apparatus according to the first embodiment. [Figure 5D] A schematic diagram illustrating an example of a gas extrusion apparatus according to the first embodiment. [Figure 5E] Schematic diagram schematically showing an example of a gas extrusion device according to the first embodiment. [Figure 6] Schematic diagram schematically showing an example of a cooling device according to the first embodiment. [Figure 7] Schematic diagram schematically showing an example of a cooling device and a gas extrusion device according to the first embodiment. [Figure 8] Graph showing the relationship between the charging rate with respect to SOC and the ease of lithium precipitation for each cooling temperature. [Embodiments for Carrying Out the Invention]

[0010] The present inventors have conducted intensive research to efficiently recover lithium from a lithium-ion battery, and have found that lithium precipitation (for example, dendrites), which is not desirable in a normal charging reaction, can be intentionally caused on the negative electrode material, and lithium can be efficiently recovered from the lithium-ion battery. Based on this finding, the present inventors have completed a battery processing method capable of efficiently recovering lithium from a lithium-ion battery.

[0011] A method for recycling a lithium-ion battery according to an embodiment of the present invention is a battery processing method for processing a lithium-ion battery including a positive electrode material, a negative electrode material, and an electrolytic solution, wherein the positive electrode material and the negative electrode material are laminated in a stacking direction, and a gas extrusion step of extruding gas generated in the lithium-ion battery toward a peripheral portion of the lithium-ion battery in a plane direction perpendicular to the stacking direction, and cooling charge of charging while cooling the lithium-ion battery to precipitate lithium on the negative electrode material and includes.

[0012] [First Embodiment] Hereinafter, a lithium-ion battery reuse system according to a first embodiment of the present invention will be described with reference to the accompanying drawings. FIG. 1 is a block diagram schematically showing a reuse system 200 for a lithium-ion battery 1. As shown in FIG. 1, the reuse system 200 includes a reuse unit 10 that secondarily uses the lithium-ion battery 1 that has been primarily used, for example, in an electric vehicle, and a recycling unit 20 that recovers lithium from the secondarily used lithium-ion battery 1.

[0013] The reuse unit 10 reuses the once-used lithium-ion battery 1 as a power storage device. Generally, the state of deterioration of a lithium-ion battery for an electric vehicle is determined based on the SOH (State Of Health) indicating how much capacity it has at full charge compared to, for example, when it is new. When the lithium-ion battery 1 is determined to be unsuitable for use in an electric vehicle based on the degree of deterioration, it is removed from the vehicle and used in the reuse unit 10 as a power storage device for various secondary uses such as storing renewable energy such as solar power generation and wind power generation, or as a backup power source during disasters. For example, when the SOH becomes 70% or less, it may be determined that it is not suitable for primary use, that is, for use in an electric vehicle.

[0014] The reuse unit 10 includes a lithium-ion battery 1 that is secondarily used as a power storage device, a charging device 12, a cooling device 201, and a gas extrusion device 301. The charging device 12 is configured to be able to charge the lithium-ion battery 1 with an arbitrary charging pattern by adjusting the voltage and current. For example, the lithium-ion battery 1 can be continuously charged with a predetermined voltage and current, and can also be charged intermittently with a predetermined voltage and current (also referred to as pulse charging). The upper limit of the charging voltage by the charging device 12 is below the withstand voltage of the lithium-ion battery 1, for example, 4.3V or less. The cooling device 201 and the gas extrusion device 301 will be described in detail after the structure of the lithium-ion battery 1 is described.

[0015] The recycling unit 20 includes a dismantling device 21 that dismantles the lithium-ion battery 1 into positive electrode material 31 and negative electrode material 35, etc., through a lithium deposition process described later, if it is determined that the lithium-ion battery 1 cannot be properly reused even in the above secondary reuse, for example, based on SOH; an extraction device 22 that extracts lithium from the dismantled negative electrode material 35; and a recovery device 23 that recovers the extracted lithium. For example, it may be determined that the battery cannot be properly reused even in secondary reuse if the SOH is 40% or less.

[0016] Figure 2 schematically shows a lithium-ion battery 1 installed in an electric vehicle. The lithium-ion battery 1 is a battery pack in which multiple battery modules 4, each incorporating functions such as a charge / discharge circuit and a cooling mechanism, are connected to each other and housed in a case. The battery module 4 is composed of multiple battery cells 3 connected to each other in series or parallel, and is adjusted to the desired capacity and voltage.

[0017] Lithium-ion battery 1 is a rechargeable lithium-ion secondary battery. In this specification, unless otherwise specified, the term lithium-ion battery may collectively refer to battery cells, battery modules, and battery packs.

[0018] Figure 3 is a schematic cross-sectional view of the battery cell 3. As shown in Figure 3, the battery cell 3 according to this embodiment is of the laminated type. The battery cell 3 has a laminated electrode body 38 in which a positive electrode material 31, a separator 34, and a negative electrode material 35 are stacked in this order in the stacking direction A, and a case 40 in which the laminated electrode body 38 is housed.

[0019] In this embodiment, the laminated electrode body 38 is constructed by stacking multiple sets of positive electrode material 31, separator 34, and negative electrode material 35 in the stacking direction A. The battery cell 3 is elongated rectangular in the width direction B when viewed from the stacking direction A.

[0020] The positive electrode material 31 comprises a positive electrode current collector 32 and a positive electrode active material 33 disposed on the surface of the positive electrode current collector 32 facing the separator 34. Multiple positive electrode current collectors 32 have positive electrode current collector ends 32a that are connected to each other at one end (left side in Figure 3) in the width direction B perpendicular to the stacking direction. Suitable metal foils for positive electrodes can be preferably used for the positive electrode current collector 32. Materials used as positive electrode active materials for lithium-ion secondary batteries can be used for the positive electrode active material 33. In this embodiment, the positive electrode current collector 32 is made of aluminum, and the positive electrode active material 33 is made of NMC (nickel, manganese, cobalt).

[0021] The negative electrode material 35 comprises a negative electrode current collector 36 and a negative electrode active material 37 disposed on the surface of the negative electrode current collector 36 facing the separator 34. Multiple negative electrode current collectors 36 have negative electrode current collector ends 36a that are connected to each other at their other ends (right side in Figure 3) in the width direction B. A metal foil suitable for a negative electrode can preferably be used for the negative electrode current collector 36. A material used as a negative electrode active material for lithium-ion secondary batteries can be used for the negative electrode active material 37. In this embodiment, the negative electrode current collector 36 is made of copper, and the negative electrode active material 37 is a carbon material (graphite) with a layered structure.

[0022] The positive electrode active material 33 and the negative electrode active material 37 contain an electrolyte 39. The electrolyte 39 is, for example, an organic solvent on which lithium ions can move. In this embodiment, the electrolyte 39 contains dimethyl carbonate (DMC), ethylene carbonate (EC), and diethyl carbonate (DEC) in a volume ratio of 1:1:1, and lithium hexafluoride phosphate (LiPF6) at a concentration of 1 mol / L.

[0023] The separator 34 is positioned between the positive electrode material 31 and the negative electrode material 35, physically and electrically separating them. The separator 34 may be a porous material having multiple minute pores through which lithium ions can pass. In this embodiment, the separator 34 is a porous membrane made of polyolefin.

[0024] Case 40 has a pair of first cases 41 and second cases 42 provided on both sides of the stacking direction A of the stacked electrode body 38. The first case 41 and the second case 42 are formed in a hat-shaped cross section. The first case 41 has a pair of flange portions 41a located at both ends in the width direction B, and a main body portion 41b located between the pair of flange portions 41a and bulging in a direction away from the second case 42 in the stacking direction A. Similarly, the second case 42 has a pair of flange portions 42a and a main body portion 42b bulging in a direction away from the first case 41.

[0025] Case 40 is formed by joining a first case 41 and a second case 42 with the positive electrode current collector end 32a and the negative electrode current collector end 36a sandwiched between their respective flange portions 41a and 42a. That is, with the laminated electrode body 38 housed in case 40, the positive electrode current collector end 32a and the negative electrode current collector end 36a are sandwiched between the pair of flange portions 41a and 42a, and the remaining portion of the laminated electrode body 38 is housed in the space defined between the pair of main body portions 41b and 42b. With the laminated electrode body 38 housed in case 40, it is pressed against the pair of main body portions 41b and 42b at a predetermined pressure in the stacking direction A. An example of the tab 43 according to the present invention is formed by the portion of the battery cell 3 sandwiched between the pair of flange portions 41a and 42a.

[0026] In this embodiment, it is assumed that gas is generated inside the lithium-ion battery 1, which is deemed unsuitable for proper reuse. When gas is generated inside the lithium-ion battery 1, the outside of the lithium-ion battery 1 swells, so the generation of gas can be confirmed by the appearance of the lithium-ion battery 1. In addition, since the internal pressure of the lithium-ion battery 1 fluctuates due to the generation of gas, the generation of gas can also be confirmed by the fluctuation in the pressing force of the gas extrusion device 301 described later.

[0027] Generally, when gas is generated within the lithium-ion battery 1, the movement of electrons between the positive electrode material 31 and the negative electrode material 35 is inhibited by the gas, making it difficult for charge-discharge reactions to occur. This gas is a by-product generated from the electrolyte 39 during the charge-discharge reactions in the primary and secondary use of the lithium-ion battery 1. This gas is, for example, methane and / or carbon dioxide.

[0028] Next, the gas extrusion device 301 will be described. The gas extrusion device 301 is a device that presses the battery cells 3 in the stacking direction A with a predetermined pressing force. The gas extrusion device 301 may be installed in the lithium-ion battery 1 that has been primarily used in an electric vehicle in order to generate a charge-discharge reaction within the lithium-ion battery 1, or it may be installed in the lithium-ion battery 1 that has been secondarily used in the reuse section 10. Alternatively, a separate gas extrusion device that can adjust the pressing force automatically or manually may be provided. The gas extrusion device 301 is not particularly limited, and any actuator such as a hydraulic cylinder or a pneumatic cylinder can be used.

[0029] Figures 5A to 5E schematically show the gas extruder 301. Figures 5A to 5E also schematically show the battery cells 3 that are pressed by the gas extruder 301. As shown in Figure 5A, the gas extruder 301 has a pair of presser pairs 302, which are provided on both sides of the stacking direction A of the battery cells 3 and are divided in the width direction B of the battery cells 3. In this embodiment, the gas extruder 301 has a central presser pair 302A located in the center of the width direction B, a side presser pair 302B located on one side of the width direction B (left side in Figure 5A), and a other side presser pair 302C located on the other side of the width direction B (right side in Figure 5A). The presser pairs 302 are not limited to three, but may be divided into two or four or more.

[0030] Next, the cooling device 201 will be described. Figure 6 is a schematic diagram of the cooling device 201. Figure 6 also schematically shows the battery cell 3 that is cooled by the cooling device. As shown in Figure 6, the cooling device 201 is provided in pairs on both sides of the stacking direction A of the battery cell 3. Alternatively, one side of the pair of cooling devices 201 may be in a form in which a single cooler covers the entire width direction B of the battery cell 3, or, as shown in Figure 6, it may be in a form of multiple pairs of coolers 202 divided in the width direction B of the battery cell 3. In this embodiment, there is a central cooler pair 202A that cools the central part 3a of the battery cell 3, and cooler pairs 202B and 202C that cool both sides 3b and 3c of the battery cell 3. When the cooler pairs 202 are divided, they may be divided into two or four or more, not just three, but it is preferable to divide them into three or more from the viewpoint of controlling the cooling area according to the deterioration state of the battery. For example, by cooling the battery cell 3 using only the central cooler pair 202A, lithium is preferentially deposited in the negative electrode material 35 located in the central part rather than at the edges in the width direction B. Furthermore, the coolers are not limited to a pair configuration and may be arranged only on one side of the stacking direction A (the upper or lower side in Figure 6).

[0031] The cooling device 201 is not limited and may be any type of cooling device. In this embodiment, a constant temperature bath is used as the cooling device 201.

[0032] Furthermore, the cooling device 201 may be positioned in contact with the gas extruder 301. For example, as shown in Figure 7, the cooling device 201 and the gas extruder 301 may be provided as a pair on both sides of the stacking direction A of the battery cell 3, with the cooling device 201 positioned on the outside. Alternatively, the cooling device 201 and the gas extruder 301 may be provided as a pair on both sides of the stacking direction A of the battery cell 3, with the cooling device 201 positioned between the battery cell 3 and the gas extruder 301.

[0033] Next, the reuse of the lithium-ion battery 1 will be explained. Figure 4 is a flowchart that schematically shows the reuse process of the lithium-ion battery 1. As shown in Figure 4, if the lithium-ion battery 1 that was installed in the electric vehicle is determined to be in a deteriorated state that is unsuitable for use in the electric vehicle, for example based on the State of Health (SOH), a reuse process (step S1) is carried out. In reuse process S1, the lithium-ion battery 1 is removed from the electric vehicle and put to secondary use in the reuse unit 10.

[0034] When a lithium-ion battery 1 is used for secondary purposes and is used as an energy storage device, and is determined to be in a predetermined state of degradation, the reuse section 10 performs a lithium deposition process (step S2) following the secondary use. In the lithium deposition process, lithium is deposited on the negative electrode material 35. The lithium deposition process includes a gas extrusion process S21, in which gas is pushed toward the peripheral edge of the lithium-ion battery in a plane perpendicular to the stacking direction, and a cooling and charging process S22, in which the lithium-ion battery is charged while being cooled, thereby depositing lithium on the negative electrode material 35.

[0035] In the gas extrusion process S21, the gas generated inside the battery cell 3 is pushed out toward the peripheral edge 3z by sequentially operating the presser pairs 302 of multiple sets of presser pairs 302 from one end 3b to the other end 3c in the width direction B, or sequentially operating them from the central part 3a in the width direction B to both sides 3b and 3c in the width direction B. Therefore, the battery processing method of this embodiment further includes a gas extrusion process in which the gas is pushed toward the peripheral edge 3z of the battery cell 3 in an in-plane direction perpendicular to the stacking direction A.

[0036] In the gas extrusion step S21, the battery cell 3 is pressed with a pressing force sufficient to allow the gas inside the battery cell 3 to move. In the subsequent cooling and charging step S22, the pressing force is, for example, 10 kPa or more and 1 MPa or less in order to generate a charge-discharge reaction inside the lithium-ion battery 1.

[0037] For example, as shown in Figure 5A, the central part 3a in the width direction B of the battery cell 3 may be pressed first, and then, as shown in Figure 5B, the sides 3b and 3c in the width direction B may be pressed as well. As a result, the gas is pushed out from the central part 3a side to the sides 3b and 3c side of the battery cell 3 in the width direction B. Note that the parts 3a, 3b, and 3c of the battery cell 3 remain pressed to prevent the pushed-out gas from flowing back into the central part 3a, etc. of the battery cell 3.

[0038] Furthermore, as shown in Figure 5C, after pressing one end 3b in the width direction B of the battery cell 3, the central part 3a in the width direction may be additionally pressed as shown in Figure 5D, and the other end 3c in the width direction B may be additionally pressed as shown in Figure 5E. As a result, the gas is pushed out from the end 3b side to the other end 3c side in the width direction B. Note that the parts 3a, 3b, and 3c of the battery cell 3 remain pressed to prevent the pushed-out gas from flowing back into the central part 3a, etc. of the battery cell 3.

[0039] While parts 3a, 3b, and 3c of the battery cell 3 are being pressed by the gas extrusion process S21, a cooling and charging process (step S22) is performed to deposit lithium on the negative electrode material 35. In the cooling and charging process S22, the lithium-ion battery 1 is charged in such a way that lithium is generated on the negative electrode material 35.

[0040] In the gas extrusion process S21, the battery cell 3 is locally pressed by activating at least some of the presser pairs 302 of the multiple presser pairs 302. Therefore, in the gas extrusion process S21, the battery cell 3 is pressed with an increased pressing force in the stacking direction A in at least a portion of it compared to the rest. Generally, in order to generate a charge-discharge reaction within the lithium-ion battery 1, the battery cell 3 needs to be pressed (i.e., constrained) in the stacking direction. In the gas extrusion process S21, the battery cell 3 is pressed with a pressing force that is at least necessary for the charge-discharge reaction to occur. For example, this pressing force is between 10 kPa and 1 MPa.

[0041] After the completion of the gas extrusion process S21 and before being subjected to the cooling and charging process S22, the pressure on the battery cell 3 may be maintained or released. In a preferred embodiment, after the completion of the gas extrusion process S21 and before being subjected to the cooling and charging process S22, the pressure on the battery cell 3 is released.

[0042] Next, in the cooling and charging process 22, the lithium-ion battery 1 is charged while being cooled by the cooling device 201 under predetermined cooling conditions. Here, the graph in Figure 7 shows the relationship between the charging rate (charging current) at which lithium begins to deposit and the State of Charge (SOC) for each temperature. Specifically, lithium is more likely to deposit on the negative electrode material 35 when charging is performed on or above the curves for each temperature. SOC is an index that indicates the charge state of the battery, and represents the battery capacity when the fully charged state is 100% and the completely discharged state is 0%. As shown in Figure 8, lithium is more likely to deposit in the lithium-ion battery 1 as the SOC increases and / or as the temperature decreases.

[0043] The cooling temperature varies depending on the operating environment and type of the lithium-ion battery 1. For example, if the lithium-ion battery 1 is a so-called capacity type (also called energy type) installed in an electric vehicle, the cooling temperature may be 20°C or lower, 10°C or lower, 0°C or lower, -5°C or lower, -10°C or lower, -20°C or lower, or -30°C or lower, and may be -50°C or higher, -40°C or higher, -30°C or higher, -25°C or higher, or -20°C or higher. From the viewpoint of reliably depositing lithium in the cooling portion, a temperature of -10°C or lower is preferred. In addition, to prevent lithium from depositing throughout the entire lithium-ion battery 1 due to excessive cooling, a cooling temperature of -50°C or higher, or -40°C or higher, is preferred. In one embodiment, the cooling temperature may be between -40°C and 10°C.

[0044] The cooling rate during cooling may be, for example, 0.1°C / min to 50°C / min. From the viewpoint of unevenly distributing lithium deposition, a cooling rate of 1°C / min to 50°C / min is preferable. In this disclosure, "cooling rate" is a parameter based on the temperature inside the battery, not the ambient temperature.

[0045] Therefore, in the cooling and charging process 22, the lithium-ion battery 1 is charged while being cooled. As a result, lithium can be deposited on a portion of the negative electrode material 35 even without high-rate charging, and the charging current can be reduced, thus saving energy.

[0046] On the other hand, in the cooling and charging process 22, if the charging while cooling only a portion of the lithium-ion battery 1 is not high-rate charging, the normal charging reaction may proceed in the uncooled portion, which may suppress lithium deposition in the cooled portion. Therefore, charging may be performed using high-rate charging.

[0047] In the cooling and charging process 22, the lithium-ion battery 1 only needs to be charged while it is cooled. The cooling of the lithium-ion battery 1 by the cooling device 201 and the charging of the lithium-ion battery 1 by the charging device 12 may start simultaneously, or one of them may start first. That is, after cooling by the cooling device 201 is performed, charging by the charging device 12 may be performed while the cooling state by the cooling device 201 is maintained.

[0048] In this specification, high-rate charging refers to charging with a large current that intentionally generates lithium in the negative electrode material 35 during charging.

[0049] If the charging current becomes excessive due to high-rate charging, undesirable side reactions may occur, such as gasification of the electrolyte 39 due to heat generation, deformation and damage to each component, and excessive charging current is undesirable from the standpoint of energy saving. For example, if the lithium-ion battery 1 is a capacity type, it is preferable to set the upper limit of the charging current to about 3C. On the other hand, if the lithium-ion battery 1 is a high-output type, it is preferable to set the upper limit of the charging current to about 20C.

[0050] For example, if the lithium-ion battery 1 is a capacity type, it is preferable to charge it with a current of, for example, 2C or more. Also, if the lithium-ion battery 1 is a so-called high-output type (also called a power type) installed in a hybrid vehicle, it is preferable to charge it with a current of, for example, 10C or more. Here, a current of 1C means the current required to fully charge each lithium-ion battery in one hour. High-rate charging allows for more efficient deposition of lithium on the negative electrode material 35 by continuously charging over a predetermined period of time.

[0051] Furthermore, in the cooling and charging process 22, charging may be performed by pulse charging. In normal charging (also called continuous charging) rather than pulse charging, normal charging reactions may occur along with lithium deposition. On the other hand, when the lithium-ion battery 1 is subjected to pulse charging, which has a higher instantaneous output compared to continuous charging, more energy is expended in the lithium deposition reaction, which requires high energy, so more lithium can be deposited efficiently compared to a normal charging reaction.

[0052] The conditions for pulse charging vary depending on the operating environment and type of the lithium-ion battery 1. For example, if the lithium-ion battery 1 is a so-called capacitive type used in electric vehicles, the frequency can be 0.1 to 100 Hz, preferably 0.1 to 10 Hz, and more preferably 0.1 to 1 Hz. The pulse charging voltage can be 3.8 to 4.3 V.

[0053] Pulse charging is preferably performed using high-rate pulse charging. In this specification, high-rate pulse charging means charging with a large current that intentionally generates lithium in the negative electrode material 35 during pulse charging.

[0054] For example, if the lithium-ion battery 1 is a capacity type, it is preferable to pulse charge it with a current of, for example, 2C or more. Also, if the lithium-ion battery 1 is a so-called high-output type (also called a power type) installed in a hybrid vehicle, it is preferable to pulse charge it with a current of, for example, 10C or more. Here, a current of 1C means the current required to fully charge each lithium-ion battery in one hour. High-rate pulse charging allows for more efficient deposition of lithium on the negative electrode material 35 by intermittently charging over a predetermined period of time.

[0055] If the charging current due to high-rate pulse charging becomes excessive, undesirable side reactions may occur, such as gasification of the electrolyte 39 due to heat generation, deformation and damage to each component, and excessive charging current is undesirable from the standpoint of energy saving. For example, if the lithium-ion battery 1 is a capacity type, it is preferable to set the upper limit of the charging current to about 3C. On the other hand, if the lithium-ion battery 1 is a high-output type, it is preferable to set the upper limit of the charging current to about 20C.

[0056] Next, the lithium-ion battery 1 is removed from the reuse section 10 and the battery dismantling process (step S3) is performed by the dismantling device 21. In the battery dismantling process, the lithium-ion battery 1 is dismantled into its constituent components, such as the positive electrode material 31, separator 34, negative electrode material 35, and case 40. If the intention is to recover only lithium, at least the negative electrode material 35 may be dismantled.

[0057] Next, a lithium extraction process (step S4) is carried out. In lithium extraction process S4, lithium is extracted from the disassembled negative electrode material 35. In lithium extraction process S4, the negative electrode current collector 36 and negative electrode active material 37 are removed from the negative electrode material 35 by the extraction device 22, after which the negative electrode material 35 is leached with water and filtered, and an aqueous solution containing lithium ions is extracted.

[0058] Alternatively, lithium may be efficiently extracted by preferentially providing the portion of the disassembled negative electrode material 35 that has a larger amount of lithium deposited in the lithium deposition step S2 or the lithium deposition step S12 described later to the lithium extraction step S4.

[0059] Finally, a lithium recovery process (step S5) is carried out to recover lithium from the aqueous solution containing lithium ions. In the lithium recovery process, the lithium is dissolved in carbonated water by the recovery device 23 and then filtered to recover the lithium as lithium carbonate.

[0060] In other words, the battery processing method according to this embodiment is A battery processing method for processing a lithium-ion battery 1 comprising a positive electrode material 31 and a negative electrode material 35, A lithium deposition step S2 is performed in which lithium is deposited onto the negative electrode material 35 by charging the lithium-ion battery 1, Battery dismantling process S3 involves dismantling at least the negative electrode material 35 from the lithium-ion battery 1, A lithium recovery process S5 is performed to extract lithium from the negative electrode material 35. It includes.

[0061] As a result, since the negative electrode material 35 is generally constructed by laminating graphite in layers on a current collector foil made of, for example, copper, it contains fewer valuable substances compared to the positive electrode material 31, which contains multiple types of valuable substances such as cobalt, nickel, and manganese. Therefore, lithium can be efficiently recovered from the negative electrode material 35 without the need for stepwise solvent extraction of multiple types of valuable metals, as is required when recovering lithium from the positive electrode material 31.

[0062] In the first embodiment described above, the case in which the lithium-ion battery 1 is provided to the reuse process S1 in the form of a battery pack and then the lithium deposition process is carried out was described as an example, but the invention is not limited to this. The lithium-ion battery 1 may be provided to the reuse process S1 and / or the lithium deposition process in the form of a battery module 4 or a battery cell 3.

[0063] [Second Embodiment] The second embodiment differs in that a second lithium deposition step S12 is used instead of the lithium deposition step S2 in the first embodiment. In the second lithium deposition step S12, a second cooling and charging step S23 is used instead of the cooling and charging step S22.

[0064] The second cooling and charging step S23 may further include a plurality of cooling areas in a plane perpendicular to the stacking direction, and cooling and charging may be performed sequentially for each cooling area. In this embodiment, the lithium-ion battery 1 is cooled sequentially for each cooling area. In this disclosure, "cooling area" refers to a part of the lithium-ion battery 1 that is being cooled.

[0065] In the second cooling and charging step 23, cooling may be performed under different conditions for each cooling area depending on the deterioration state of the cooling area. For example, in the second cooling and charging step 23, the pressing force in the stacking direction may be increased for the cooling area compared to the remaining cooling areas. The increase in pressing force at the cooling area can be achieved by the presser pair 302 attached to the cooler pair 202, as shown in Figure 7. By subjecting the area of ​​the negative electrode material 35 where more lithium is to be deposited to cooling and pressing, lithium can be deposited efficiently. For example, if the deterioration state of the central part 3a of the battery cell 3 is more severe than that of the side parts 3b and 3c, lithium deposition may preferentially occur in the central part 3a by cooling while pressing the central part 3a in the second cooling and charging step 23.

[0066] The reuse system 200 according to the second embodiment, as shown in Figure 1, is equipped with a cooling device 201 and an extrusion device 301, similar to the reuse system 200 according to the first embodiment, and the lithium-ion battery 1 is supplied to the reuse section 10 in the form of a battery cell 3.

[0067] In the second embodiment described above, the lithium-ion battery 1 is provided in the form of a battery cell 3 in the reuse process S1, and then the second lithium deposition process S12 is carried out as an example, but the invention is not limited to this. The lithium-ion battery 1 may be provided in the form of a battery pack or battery module 4 in the reuse process S1 and / or the second lithium deposition process S12. In this case, a cooling device 201 may be pre-built inside the battery pack or battery module 4.

[0068] The lithium-ion battery 1 reuse system 200 relating to this disclosure is not limited to the configuration described in the above embodiment, and various modifications are possible.

[0069] In the above embodiment, a laminated lithium-ion battery was described as an example, but it is not limited to this. For example, a cylindrical or rectangular lithium-ion battery may be used, which is constructed by winding a strip-shaped laminated electrode body, in which a strip-shaped positive electrode material, a strip-shaped separator, and a strip-shaped negative electrode material are stacked in the stacking direction A, into a cylindrical or rectangular shape. In the case of cylindrical and rectangular types, the stacking direction corresponds to the radial direction perpendicular to the winding direction.

[0070] Although the explanation was given on a cell-by-cell basis, it can also be done on a module-by-module or battery pack-by-battery basis. If done on a battery pack basis, a gas extrusion device, cooling device, etc. may be pre-installed inside the battery pack.

[0071] [Note] According to the lithium-ion battery 1 reuse system 200 relating to this disclosure, the following aspects are provided.

[0072] [Aspect 1] A battery processing method for a lithium-ion battery comprising a positive electrode material and a negative electrode material, wherein the positive electrode material and the negative electrode material are stacked in a stacking direction, and gas is present inside the battery, A gas extrusion step in which the gas is pushed toward the peripheral edge of the lithium-ion battery in a plane perpendicular to the stacking direction, A cooling and charging process in which the lithium-ion battery is charged while being cooled, thereby depositing lithium on the negative electrode material. A battery processing method, including the following.

[0073] [Aspect 2] In the gas extrusion step, the gas is extruded from the central part of the lithium-ion battery in the plane. The battery processing method described in Embodiment 1.

[0074] [Aspect 3] The lithium-ion battery further includes a plurality of cooling portions in a plane perpendicular to the stacking direction, The battery processing method according to embodiment 1 or 2, wherein the cooling and charging step is performed sequentially for each cooling part.

[0075] [Aspect 4] The battery processing method according to embodiment 3, wherein in the cooling and charging step, the cooling is performed under different cooling conditions for each cooling part according to the deterioration state of the cooling part.

[0076] [Aspect 5] The battery processing method according to embodiment 3 or 4, wherein during the cooling and charging step, the pressing force applied to the cooling portion in the stacking direction is increased compared to the remaining cooling portion.

[0077] [Aspect 6] The battery processing method according to any one of embodiments 1 to 5, wherein the cooling and charging step is performed by pulse charging.

[0078] [Aspect 7] A battery dismantling step, which involves dismantling at least the negative electrode material from the lithium-ion battery, A lithium extraction step for extracting lithium from the negative electrode material, A battery processing method according to any one of embodiments 1 to 6, further comprising the above.

[0079] [Aspect 8] A battery processing system for processing a lithium-ion battery comprising a positive electrode material, a negative electrode material, and an electrolyte, wherein the positive electrode material and the negative electrode material are stacked in a stacking direction, A gas extrusion device capable of pressing the lithium-ion battery in sections, A cooling device capable of cooling the lithium-ion battery in sections, A charging device capable of recharging the lithium-ion battery and A battery processing system, including a battery processing system.

[0080] [Aspect 9] The battery processing system according to embodiment 8, wherein the gas extrusion device is capable of extruding the gas toward the peripheral edge of the lithium-ion battery by sequentially pressing the gas in the stacking direction under predetermined pressing conditions.

[0081] [Aspect 10] The charging device is a charging device capable of pulse charging. The battery processing system according to embodiment 8 or 9. [Explanation of Symbols]

[0082] 1. Lithium-ion battery 3 battery cells 4 Battery Modules 10. Reuse Department 12 Charging device 20 Recycling Department 21 Demolition equipment 22 Extraction device 23 Recovery device 31 Positive electrode material 34 Separator 35. Negative electrode material 38. Stacked electrode body 39 Electrolyte 40 cases 200 Reuse Systems 201 Cooling device 301 Gas extruder

Claims

1. A battery processing method for a lithium-ion battery comprising a positive electrode material and a negative electrode material, wherein the positive electrode material and the negative electrode material are stacked in a stacking direction, and gas is present inside the battery, A gas extrusion step in which the gas is pushed toward the peripheral edge of the lithium-ion battery in a plane perpendicular to the stacking direction, A cooling and charging process in which the lithium-ion battery is charged while being cooled, thereby depositing lithium on the negative electrode material. A battery processing method, including the following.

2. In the gas extrusion step, the gas is extruded from the central part of the lithium-ion battery in the plane. The battery processing method according to claim 1.

3. The lithium-ion battery further includes a plurality of cooling portions in a plane perpendicular to the stacking direction, The battery processing method according to claim 1, wherein the cooling and charging step is performed sequentially for each of the cooling parts.

4. The battery processing method according to claim 3, wherein the cooling and charging step is performed under different cooling conditions for each cooling part according to the deterioration state of the cooling part.

5. The battery processing method according to claim 3, wherein, during the cooling and charging step, the pressing force applied to the cooling portion in the stacking direction is increased compared to the remaining cooling portion.

6. The battery processing method according to claim 1, wherein the cooling and charging step is performed by pulse charging.

7. A battery dismantling step, which involves dismantling at least the negative electrode material from the lithium-ion battery, A lithium extraction step for extracting lithium from the negative electrode material, The battery processing method according to claim 1, further comprising:

8. A battery processing system for processing a lithium-ion battery comprising a positive electrode material, a negative electrode material, and an electrolyte, wherein the positive electrode material and the negative electrode material are stacked in a stacking direction, A gas extrusion device capable of pressing the lithium-ion battery in sections, A cooling device capable of cooling the lithium-ion battery in sections, A charging device capable of recharging the lithium-ion battery and A battery processing system, including a battery processing system.

9. The battery processing system according to claim 8, wherein the gas extrusion device is capable of extruding the gas inside the battery toward the peripheral edge of the lithium-ion battery by sequentially pressing it in the stacking direction under predetermined pressing conditions.

10. The charging device is a charging device capable of pulse charging. The battery processing system according to claim 8.

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