Battery processing method

Abstract

Provided is a battery processing method capable of efficiently recovering lithium from a lithium ion battery. A battery processing method for processing a lithium ion battery including a positive electrode material and a negative electrode material includes a first lithium deposition step for depositing lithium on the negative electrode material by performing pulse charging while cooling the lithium ion battery.

Description

Technical Field

[0001] This invention relates to a battery processing method and a battery processing system. Background Technology

[0002] In recent years, the adoption of lithium-ion batteries as onboard batteries for electric vehicles, including electric cars and hybrid vehicles, has been expanding. Lithium-ion batteries contain valuable lithium. The aim is to achieve resource recycling by reusing the valuable lithium from already used lithium-ion batteries.

[0003] Patent document 1 discloses a method for recovering lithium from a cathode material after increasing the amount of lithium contained in the cathode material by discharging an already used lithium-ion battery.

[0004] Existing technical documents

[0005] Patent documents

[0006] Patent document 1: Japanese Patent Application Publication No. 2022-049831.

[0007] The technical problem that the invention aims to solve

[0008] Cathode materials are generally constructed by forming a positive electrode active material using current-collecting foils such as aluminum. For example, in the case of a ternary (NMC) system, the positive electrode active material contains valuable substances such as nickel, manganese, and cobalt. To recover these valuable substances from the positive electrode active material, the material is calcined together with a reducing agent, then pulverized and screened for black lumps containing the positive electrode active material. Next, the black lumps are subjected to staged solvent extraction to sequentially extract manganese, cobalt, and nickel, and finally lithium. Therefore, lithium recovery, in particular, requires considerable effort. Summary of the Invention

[0009] The technical problem of the present invention is to provide a battery processing method and battery processing system that can efficiently recover lithium from lithium-ion batteries.

[0010] Technical means for solving technical problems

[0011] This invention provides a battery processing method.

[0012] This is a battery processing method for processing lithium-ion batteries containing positive electrode materials and negative electrode materials, comprising:

[0013] A first lithium deposition process in which lithium is deposited on the negative electrode material while the lithium-ion battery is being cooled and pulsed charged.

[0014] The effects of the invention

[0015] According to the present invention, lithium can be efficiently recovered from the negative electrode of a lithium-ion battery. Attached Figure Description

[0016] Figure 1 This is a block diagram schematically representing the recycling system involved in the first embodiment.

[0017] Figure 2 This is a three-dimensional diagram showing the general structure of a lithium-ion battery.

[0018] Figure 3 It is a cross-sectional view showing the general structure of a single battery cell.

[0019] Figure 4 It is a flowchart that roughly represents the process of reusing lithium-ion batteries.

[0020] Figure 5 This is a schematic diagram that represents an example of the cooling device according to the first embodiment.

[0021] Figure 6 It is a graph showing the relationship between the charging rate relative to the state of charge (SOC) and the ease of lithium deposition at each cooling temperature.

[0022] Symbol Explanation

[0023] 1 Lithium-ion battery

[0024] 3 battery cells

[0025] 4 battery components

[0026] 10 Reuse Department

[0027] 12 charging devices

[0028] 20 Recycling Department

[0029] 21 Dismantling Device

[0030] 22 Extraction device

[0031] 23 Recycling Unit

[0032] 31 Cathode Material

[0033] 34 partitions

[0034] 35 Anode Material

[0035] 38-layer stacked electrode body

[0036] 39 Electrolyte

[0037] 40 housing

[0038] 200 Reuse System

[0039] 201 Cooling device. Detailed Implementation

[0040] In order to efficiently recover lithium from lithium-ion batteries, the inventors of this invention conducted in-depth research and discovered that intentionally generating undesirable lithium deposition (e.g., dendrites) in the negative electrode material during the normal charging reaction enables efficient lithium recovery from lithium-ion batteries. Based on this insight, the inventors of this invention have completed a battery processing method capable of efficiently recovering lithium from lithium-ion batteries.

[0041] A method for reusing lithium-ion batteries according to one embodiment of the present invention.

[0042] This is a battery processing method for processing lithium-ion batteries containing positive electrode materials and negative electrode materials, comprising:

[0043] In the first lithium deposition process, lithium is deposited on the negative electrode material while the lithium-ion battery is being cooled and pulse-charged.

[0044] [First Implementation Method]

[0045] Hereinafter, a lithium-ion battery recycling system according to the first embodiment of the present invention will be described with reference to the accompanying drawings. Figure 1 This is a schematic block diagram illustrating a recycling system 200 for a lithium-ion battery 1. (See diagram for example.) Figure 1 As shown, the reuse system 200 includes, for example, a reuse unit 10 for reusing a lithium-ion battery 1 after its first use in an electric vehicle and a recovery unit 20 for recovering lithium from the reused lithium-ion battery 1.

[0046] The reuse unit 10 reuses the lithium-ion battery 1 after its first use as an energy storage device. Generally, the degradation status of lithium-ion batteries used in electric vehicles is determined based on their State of Health (SOH), which indicates, for example, their capacity when fully charged compared to when they were new. When the lithium-ion battery 1 is determined to be unsuitable for use in an electric vehicle based on its degradation level, it is removed from the vehicle and used in the reuse unit 10 as an energy storage device for various secondary uses, such as storage of renewable energy sources like solar power and wind power, or as a backup power source during disasters. For example, if the SOH is below 70%, it may be determined that the battery is unsuitable for primary use, i.e., unsuitable for use in an electric vehicle.

[0047] The reuse unit 10 includes a lithium-ion battery 1 that is reused as an energy storage device, a charging device 12, and a cooling device 201. The charging device 12 is configured to adjust the voltage and current to intermittently charge the lithium-ion battery 1 with a specified voltage and current (also known as pulse charging). The upper limit of the charging voltage of the charging device 12 is below the withstand voltage of the lithium-ion battery 1, for example, below 4.3V.

[0048] The cooling device 201 is not limited and can be any type of cooling device. In this embodiment, a constant temperature bath is used as the cooling device 201.

[0049] The recycling unit 20 includes: a disassembly device 21, which, after a lithium-ion battery 1 is determined to be unsuitable for secondary use based on, for example, the state of oxygen (SOH), disassembles the lithium-ion battery 1 into positive electrode material 31 and negative electrode material 35, etc., through a lithium deposition process described later; an extraction device 22, which extracts lithium from the disassembled negative electrode material 35; and a recycling device 23, which recovers the extracted lithium. For example, it is also possible that if the SOH is below 40%, it is determined that the battery 1 is unsuitable for secondary use.

[0050] Figure 2 This diagram roughly illustrates a lithium-ion battery 1 installed in an electric vehicle. The battery assembly 4 of the lithium-ion battery 1 has functions such as a charging / discharging circuit and a cooling mechanism, and multiple battery assemblies 4 are interconnected to form a battery pack housed in a casing. The battery assembly 4 is composed of multiple individual battery cells 3 connected in series or parallel, and is adjusted to the desired capacity and voltage.

[0051] Lithium-ion battery 1 is a rechargeable lithium-ion secondary battery. In this specification, unless otherwise stated, the terms "cell battery," "cell battery assembly," and "cell battery pack" are sometimes collectively referred to as "lithium-ion battery."

[0052] Figure 3 This is a schematic cross-sectional view of battery cell 3. (e.g.) Figure 3 As shown, the battery cell 3 involved in this embodiment is a stacked type. The battery cell 3 has a stacked 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 housing 40 that houses the stacked electrode body 38.

[0053] In this embodiment, the stacked electrode body 38 is formed by stacking multiple sets of positive electrode material 31, separator 34, and negative electrode material 35 in the stacking direction A. The stacked electrode body 38 has a width direction B (in the direction of width) orthogonal to the stacking direction A. Figure 3 One end of the middle (in the left-right direction) (in) Figure 3 The positive current collector end 32a (left side) is connected to multiple positive current collectors 32, and at the other end (in... Figure 3 The negative electrode current collector end 36a (right side, middle) is connected to multiple negative electrode current collectors 36. Viewed from the stacking direction A, the battery cell 3 is a slender rectangular shape in the width direction B.

[0054] The positive electrode material 31 has a positive current collector 32 and a positive active material 33 stacked on the surface of the positive current collector 32 facing the separator 34. The plurality of positive current collectors 32 have one end in the width direction B orthogonal to the stacking direction. Figure 3 The positive electrode current collector 32a is connected to the positive electrode on the left side of the image. The positive electrode current collector 32 can preferably be made of a metal foil suitable for the positive electrode. The positive electrode active material 33 can be a material used as the positive electrode active material in lithium-ion secondary batteries. 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).

[0055] The negative electrode material 35 has a negative electrode current collector 36 and a negative electrode active material 37 stacked on the surface of the negative electrode current collector 36 facing the separator 34. The plurality of negative electrode current collectors 36 have another end in the width direction B. Figure 3 The negative electrode current collector 36a is connected to the negative electrode on the right side of the image. The negative electrode current collector 36 can preferably be made of a metal foil suitable for a negative electrode. The negative electrode active material 37 can be a material used as a negative electrode active material in lithium-ion secondary batteries. 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) containing a layered structure.

[0056] 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 in 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 contains lithium hexafluoride phosphate (LiPF6) at a concentration of 1 mol / L.

[0057] A separator 34 is disposed between the positive electrode material 31 and the negative electrode material 35, physically and electrically separating them. The separator 34 can be a porous body with multiple tiny pores through which lithium ions can pass. In this embodiment, the separator 34 is a porous membrane made of polyolefin.

[0058] The housing 40 has a first housing 41 and a second housing 42 arranged in pairs on both sides of the stacking direction A of the stacked electrode body 38. The first housing 41 and the second housing 42 are formed in a cap-shaped cross-section. The first housing 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 protruding in the stacking direction A in a direction away from the second housing 42. Similarly, the second housing 42 has a pair of flange portions 42a and a main body portion 42b protruding in a direction away from the first housing 41.

[0059] The first housing 41 and the second housing 42 are joined together with the positive electrode current collector 32a and the negative electrode current collector 36a sandwiched between their respective flanges 41a and 42a, thereby forming the housing 40. That is, with the stacked electrode body 38 housed in the housing 40, the positive electrode current collector 32a and the negative electrode current collector 36a are sandwiched between a pair of flanges 41a and 42a, and the remaining portion of the stacked electrode body 38 is housed in a space defined between a pair of main body portions 41b and 42b. With the stacked electrode body 38 housed in the housing 40, it is pressed together with a predetermined pressure in the stacking direction A by the pair of main body portions 41b and 42b. The portion of the battery cell 3 sandwiched between a pair of flanges 41a and 42a constitutes an example of the tab 43 (Japanese: タブ) according to the present invention.

[0060] Next, the reuse of lithium-ion battery 1 will be explained. Figure 4 This is a flowchart that roughly represents the process of reusing lithium-ion battery 1. For example... Figure 4 As shown, when the lithium-ion battery 1 installed in the electric vehicle is determined to be in a deteriorated state that is not suitable for use in the electric vehicle based on, for example, SOH, a recycling process (step S1) is carried out to remove the lithium-ion battery 1 from the electric vehicle and reuse it in the recycling unit 10.

[0061] When the lithium-ion battery 1 is used for secondary recycling as an energy storage device 11 and is determined to be in a predetermined deterioration state, it is then reused in the recycling unit 10, where a lithium deposition process (step S2) is performed to deposit lithium on the negative electrode material 35. In the lithium deposition process S2, lithium is deposited on the negative electrode material 35. In the lithium deposition process S2, the lithium-ion battery 1 is pulse-charged while being cooled to cause lithium to be deposited on the negative electrode material 35.

[0062] Figure 5 This is a schematic diagram showing the cooling device 201. Figure 5 In the image, the battery cell 3, cooled by the cooling device, is shown in a general sense. For example... Figure 5 As shown, cooling devices 201 are arranged in pairs on both sides of the stacking direction A of the battery cell 3. Alternatively, one side of a pair of cooling devices 201 can also be arranged such that a single cooling element covers the entire width direction B of the battery cell 3, as shown. Figure 5 As shown, the battery cell 3 can also be divided into multiple sets of cooling elements 202 along the width direction B. In this embodiment, it has a central cooling element pair 202A for cooling the central portion 3a of the battery cell 3 and side cooling element pairs 202B and 202C for cooling the two side portions 3b and 3c of the battery cell 3. Figure 5As shown, the electrode portion within the area enclosed by the dashed line and the side of the battery cell 3 is the central portion 3a, and the electrode portions on both sides of this area are the side portions 3b and 3c. When the cooling element pair 202 is divided, it is not limited to being divided into three groups; it can also be divided into two or more groups. For example, by cooling the battery cell 3 using only the central cooling element pair 202A, lithium preferentially deposits in the negative electrode material 35 located in the central portion relative to the end in the width direction B. Furthermore, the cooling elements are not limited to a pair; for example, they can be disposed only on one side in the stacking direction A. Figure 5 (The upper or lower side of the middle).

[0063] In the lithium deposition process S2, the lithium-ion battery 1 is cooled and charged simultaneously by the cooling device 201 under specified cooling conditions. Figure 6 The graph shows the relationship between the charging rate and the ease of lithium deposition at each temperature relative to SOC (State of Charge). Specifically, if charging is performed in the region above the SOC at each temperature, lithium is more easily deposited on the negative electrode material. SOC is an indicator of the battery's state of charge and represents the battery capacity when fully charged (100%) and fully discharged (0%). Figure 6 As shown, the higher the SOC and / or the lower the temperature, the easier it is for lithium-ion battery 1 to produce lithium.

[0064] In the lithium deposition process S2, cooling to the temperature at which lithium deposition begins is preferably performed. Here, "the temperature at which lithium deposition begins" refers to the temperature determined by the SOC and charging rate of the lithium-ion battery 1, for example, in... Figure 6 In this study, a curve (hereinafter referred to as the "temperature curve") is used to represent the relationship between State of Charge (SOC) and charging rate when the "temperature at which lithium begins to deposit" is 0°C, -10°C, or -20°C. For example, if the measured SOC of the lithium-ion battery 1 to be reused is set as X, and the charging rate in any chosen lithium deposition process is set as Y, then... Figure 6 As shown, the intersection of X and Y lies between -10℃ and -20℃. In this case, -20℃ to -10℃ is the "temperature at which lithium begins to deposit". There is no particular limitation on the method for determining the SOC of the lithium-ion battery 1; known methods can be used. For example, an SOC-open-circuit voltage (OCV) curve can be derived based on a known battery model of the lithium-ion battery 1, and then the OCV of the battery can be measured and calculated by fitting the SOC-OCV curve.

[0065] The cooling temperature varies depending on the operating environment and type of the lithium-ion battery 1. For example, in the case of a so-called capacity-type (also known as energy-type) lithium-ion battery 1 used in electric vehicles, the temperature can be below 20°C, below 10°C, below 0°C, below -5°C, below -10°C, below -20°C, or below -30°C; or above -50°C, above -40°C, above -30°C, above -25°C, or above -20°C. From the viewpoint of reliably depositing lithium in the cooling section, a temperature below 10°C is preferred. Furthermore, to prevent lithium deposition throughout the lithium-ion battery 1 due to overcooling, the cooling temperature is preferably above -40°C. In one embodiment, the cooling temperature can be from -40°C to 10°C.

[0066] Although not bound by theory, by setting the cooling temperature within the aforementioned range, lithium seed crystals can be deposited from an earlier stage in the lithium deposition process S2, which can lead to the deposition of more lithium after the lithium deposition process S2 is completed.

[0067] In this specification, "capacity type" for lithium-ion battery 1 refers to a capacity of 600 Wh / L or higher. Additionally, "high output type" for lithium-ion battery 1 refers to an output density (kW / kg or kW / L) of 4000 kW / L or higher.

[0068] The cooling rate can be, for example, from 0.1°C / min to 50°C / min. From the viewpoint of reducing the non-uniformity of lithium deposition sites, the cooling rate is preferably from 1°C / min to 50°C / min. Furthermore, in this invention, the "cooling rate" is a parameter based on the internal temperature of the battery, not the ambient temperature.

[0069] Furthermore, in the lithium deposition process S2, the lithium-ion battery 1 is pulse-charged while being cooled, and lithium is deposited on the negative electrode material 35. By cooling the lithium-ion battery 1 in the lithium deposition process S2, lithium seed crystals can be deposited on the negative electrode material 35 from a relatively early stage during the pulse charging in this process. Further pulse charging causes lithium to be deposited sequentially on these seed crystals, resulting in seed crystal growth. Therefore, starting the deposition of lithium seed crystals on the negative electrode material 35 from an early stage can lead to the deposition of more lithium after the lithium deposition process S2 is completed.

[0070] Furthermore, in the lithium deposition process S2, the lithium-ion battery 1 is pulse-charged. Normal charging (also known as continuous charging) via non-pulse charging can also produce a normal charging reaction along with lithium deposition. On the other hand, if the lithium-ion battery 1 is subjected to pulse charging, which has a higher instantaneous output compared to continuous charging, more energy is consumed due to the high-energy lithium deposition reaction, thus allowing for more efficient lithium deposition compared to the usual charging reaction.

[0071] The conditions for pulse charging vary depending on the usage environment and type of the lithium-ion battery 1. For example, in the case of a so-called capacity-type lithium-ion battery 1 used in an electric vehicle, the pulse charging frequency can be 0.1 to 100 Hz, preferably 0.1 to 10 Hz, and more preferably 0.1 to 1 Hz. In addition, the pulse charging voltage can be 3.8 to 4.3 V.

[0072] Pulse charging is preferably performed using high-rate pulse charging. Furthermore, in this specification, high-rate pulse charging refers to charging that intentionally generates a large current, similar to that required for lithium, in the negative electrode material 35 during pulse charging. For example, in this embodiment, high-rate pulse charging is performed with a current exceeding that required to fully charge the lithium-ion battery 1 within two hours.

[0073] For example, when the lithium-ion battery 1 is a capacity-type battery, it is preferable to perform pulse charging with a current of, for example, 2C or higher. Furthermore, when the lithium-ion battery 1 is a so-called high-output type (also called a power type) battery used in hybrid electric vehicles, it is preferable to perform pulse charging with a current of, for example, 10C or higher. Here, 1C refers to the current required to fully charge each lithium-ion battery within one hour. By using high-rate pulse charging and continuously charging within a specified time, lithium can be deposited more efficiently on the negative electrode material 35.

[0074] If the charging current caused by high-rate pulse charging is too large, undesirable side reactions may occur, such as vaporization of the electrolyte 39 due to heat generation, deformation and damage to various components. From an energy-saving point of view, excessive charging current is also undesirable. For example, when 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, when 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.

[0075] Here, in the lithium deposition process S2, charging can be performed while the lithium-ion battery 1 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 can start simultaneously, or either can start first. That is, after cooling by the cooling device 201, charging can be performed by the charging device 12 while maintaining the cooling state of the cooling device 201. From the viewpoint of depositing lithium seed crystals at the earliest possible stage, it is preferable to start cooling first.

[0076] Next, the lithium-ion battery 1 is removed from the recycling section 10 and subjected to a battery dismantling process using the dismantling device 21 (step S3). In the battery dismantling process, the lithium-ion battery 1 is dismantled into components such as the positive electrode material 31, the separator 34, the negative electrode material 35, and the casing 40. Furthermore, if only lithium is intended for recycling, at least the negative electrode material 35 can be dismantled. The dismantling device 21 can be any device that automatically dismantles the lithium-ion battery 1. Alternatively, the lithium-ion battery 1 can be dismantled manually using tools or the like without using the dismantling device 21.

[0077] Next, a lithium extraction process (step S4) is performed. In lithium extraction step S4, lithium is extracted from the disassembled negative electrode material 35. In lithium extraction step S4, the negative electrode material 35 is percolated with water through the extraction device 22 and then filtered to remove the negative electrode current collector 36 and the negative electrode active material 37 from the negative electrode material 35, thereby extracting an aqueous solution containing lithium ions.

[0078] In addition, lithium can be extracted efficiently by preferentially supplying the portion of the disassembled negative electrode material 35 that has a higher lithium deposition amount than other portions in the lithium deposition process S2 or the second lithium deposition process S22 described later to the lithium extraction process S4.

[0079] Finally, a lithium recovery process (step S5) is performed. In lithium recovery step S5, lithium is recovered from an aqueous solution containing lithium ions. In lithium recovery step S5, after the lithium is soluble in carbonated water by the recovery device 23, it is recovered as lithium carbonate by filtration.

[0080] The negative electrode material 35 is typically constructed by laminating graphite in layers of current-collecting foil, such as copper. Therefore, compared to the positive electrode material 31, which contains multiple valuable substances such as cobalt, nickel, and manganese, it contains fewer valuable substances. Consequently, unlike the process of extracting multiple valuable metals in stages when recovering lithium from the positive electrode material 31, lithium can be recovered from the negative electrode material 35 efficiently.

[0081] In the first embodiment described above, the case in which the lithium-ion battery 1 is provided to the recycling process S1 in the form of a battery pack, and then the lithium deposition process S2 is performed, has been described as an example, but it is not limited to this. In the recycling process S1 and / or the lithium deposition process S2, the lithium-ion battery 1 may also be provided in the form of a battery module 4 or a battery cell 3.

[0082] [Second Implementation]

[0083] In the second embodiment, a lithium deposition process S12 is performed instead of the lithium deposition process S2 described in the first embodiment. The difference in the lithium deposition process S12 is that, in addition to the lithium deposition process S2 described in the first embodiment, a second lithium deposition process S22 is also employed. The second lithium deposition process S22 is a process in which lithium-ion battery 1 is discharged at least once, followed by pulse charging, to deposit lithium onto the negative electrode material 35.

[0084] In the discharge process of the second lithium deposition step S22, the discharge rate is not particularly limited; for example, it can be discharged at the same rate as the charging rate performed in the lithium deposition step S2. Furthermore, the discharge can be a pulsed discharge or a continuous discharge, but continuous discharge is preferred.

[0085] Reference Figure 1 The discharge in the second lithium deposition process S22 can be performed by the recycling system 200 including a discharge device, or by using a discharge-capable device as a charging device 12. This discharge device can adjust the voltage and current to continuously discharge at a specified voltage and current. Alternatively, it can be configured to discharge intermittently at a specified voltage and current. The upper limit of the discharge voltage of the discharge device is below the withstand voltage of the lithium-ion battery 1, for example, below 4.3V.

[0086] The cooling conditions in the second lithium deposition process S22 can be any of the conditions listed in the description of the lithium deposition process S2. Alternatively, the cooling conditions in the second lithium deposition process S22 can be set differently from those in the lithium deposition process S2, depending on factors such as the battery's degradation state and the lithium ion absorption state in the negative electrode active material 37. For example, in the second lithium deposition process S22, from the viewpoint of depositing more lithium seed crystals than in the lithium deposition process S2, the cooling temperature can be 1°C, 2°C, 3°C, or 5°C lower than that in the lithium deposition process S2.

[0087] The pulse charging conditions in the second lithium deposition process S22 can be any of the conditions listed in the description of the lithium deposition process S2. Alternatively, the cooling conditions in the second lithium deposition process S22 can be set differently from those in the lithium deposition process S2, depending on factors such as the battery's degradation state. For example, in the second lithium deposition process S22, from the viewpoint of depositing more lithium than in the lithium deposition process S2, pulse charging can be performed at a higher rate than in the lithium deposition process S2.

[0088] In the second lithium deposition process S22, discharge and pulse charging are performed at least once. From the viewpoint of ensuring that more lithium is deposited in the negative electrode material 35 after the second lithium deposition process S22, the number of repetitions of discharge and pulse charging can be 2 or more, 3 or more, 5 or more, 7 or more, 8 or more, or 10 or more, preferably 3 or more. Furthermore, as the number of repetitions of discharge and pulse charging increases, the amount of lithium that can be deposited in the negative electrode material 35 converges to a certain value, therefore, excessive repetitions will lead to energy loss. Therefore, the number of repetitions can be 30 or less, 25 or less, 20 or less, 15 or less, 10 or less, or 8 or less, preferably 10 or less.

[0089] By heating in the second lithium deposition process S22, the re-ionized lithium is absorbed in the region (active region) of the negative electrode active material 37 where lithium ion absorption capacity still remains. Through subsequent cooling and charging, lithium is deposited again, and by further heating, lithium ions are repeatedly absorbed in the active region of the negative electrode active material 37, thereby converging the overall lithium ion absorption capacity of the negative electrode active material 37 to a certain upper limit. Therefore, by repeating the heating, cooling, and charging process an appropriate number of times in the second lithium deposition process S22, more lithium can be deposited in the negative electrode material 35 compared to the case where only the second lithium deposition process S22 is performed.

[0090] In the second embodiment described above, the case where the second lithium deposition process S22 is performed after the lithium-ion battery 1 is provided to the recycling process S1 as a single cell 3 is used as an example, but it is not limited to this. In the recycling process S1 and / or the second lithium deposition process S22, the lithium-ion battery 1 may also be provided as a battery pack or battery assembly 4. In this case, a cooling device 201 may be pre-built inside the battery pack or battery assembly 4.

[0091] The lithium-ion battery 1 recycling system 200 of the present invention is not limited to the structure described in the above embodiments, and various modifications can be made.

[0092] In the above embodiments, a stacked type lithium-ion battery was described as an example, but it is not limited to this. For example, as a lithium-ion battery, a cylindrical or square type can also be used, which is formed by winding a strip-shaped stacked electrode body, in which strip-shaped positive electrode material, strip-shaped separator, and strip-shaped negative electrode material are stacked along the stacking direction A, into a cylindrical or square shape. In the case of cylindrical or square type, the stacking direction is equivalent to the radial direction orthogonal to the winding direction.

[0093] Although described on a single-unit basis, it can also be implemented on a module-by-module or battery pack-by-pack basis. When implemented on a battery pack-by-pack basis, pressing devices, cooling devices, etc., can be pre-installed within the battery pack.

[0094] [Postscript]

[0095] The lithium-ion battery 1 recycling system 200 according to the present invention provides the following method.

[0096] [Method 1]

[0097] A battery processing method is a battery processing method for processing lithium-ion batteries containing positive electrode materials and negative electrode materials, comprising:

[0098] A first lithium deposition process in which lithium is deposited on the negative electrode material while the lithium-ion battery is being cooled and pulsed charged.

[0099] [Method 2]

[0100] According to the battery processing method described in Method 1,

[0101] In the first lithium deposition process, the temperature is cooled to the temperature at which lithium begins to deposit.

[0102] [Method 3]

[0103] According to the battery processing method described in method 1 or 2,

[0104] In the first lithium deposition process, the lithium-ion battery is cooled to a range of -40°C to 10°C.

[0105] [Method 4]

[0106] According to any one of the battery processing methods described in methods 1 to 3

[0107] In the first lithium deposition process, the pulse charging is performed using a high-rate pulse charging method.

[0108] [Method 5]

[0109] According to any one of the battery processing methods described in methods 1 to 4

[0110] In the first lithium deposition process, the pulse charging is performed at a pulse charging frequency of 0.1Hz to 100Hz.

[0111] [Method 6]

[0112] According to any one of the battery processing methods described in methods 1 to 5

[0113] It also includes a second lithium deposition process: after the first lithium deposition process, the lithium-ion battery is discharged at least once, followed by a pulse charge to deposit lithium on the negative electrode material.

[0114] [Method 7]

[0115] The battery processing method according to any one of methods 1 to 6 further includes:

[0116] At least a battery disassembly process for disassembling the negative electrode material from the lithium-ion battery; and

[0117] The lithium extraction process for extracting lithium from the negative electrode material.

[0118] [Method 8]

[0119] A battery processing system for processing lithium-ion batteries containing positive electrode materials and negative electrode materials includes: a cooling device capable of cooling the lithium-ion battery; and a charging device capable of pulse charging the lithium-ion battery.

[0120] [Method 9]

[0121] According to the battery processing system described in Method 8,

[0122] It also includes a discharge device that enables the lithium-ion battery to discharge.

[0123] [Method 10]

[0124] According to the battery processing method described in Method 1,

[0125] In the first lithium deposition process, the pulse charging is performed intermittently with a specified voltage and current by a charging device that adjusts the voltage and current.

[0126] [Method 11]

[0127] According to the battery processing method described in Method 1,

[0128] The lithium-ion battery is formed by stacking the positive electrode material and the negative electrode material along the stacking direction.

[0129] In the first lithium deposition process, the lithium-ion battery is cooled by a cooling device, which is arranged in pairs on both sides of the lithium-ion battery in the stacking direction.

[0130] [Method 12]

[0131] According to the battery processing method described in Method 11,

[0132] The cooling device has a central cooling element pair for cooling the central portion of the lithium-ion battery and a pair of side cooling elements for cooling the two sides of the lithium-ion battery.

[0133] [Method 13]

[0134] According to the battery processing method described in Method 4,

[0135] The high-rate charging refers to charging with a current greater than that required to fully charge the lithium-ion battery in two hours.

Claims

1. A battery processing method for processing a lithium-ion battery containing a positive electrode material and a negative electrode material, characterized in that, Include: A first lithium deposition process in which lithium is deposited on the negative electrode material while the lithium-ion battery is being cooled and pulsed charged.

2. The battery processing method according to claim 1, characterized in that, In the first lithium deposition process, the temperature is cooled to the temperature at which lithium begins to deposit.

3. The battery processing method according to claim 1, characterized in that, In the first lithium deposition process, the lithium-ion battery is cooled to a range of -40°C to 10°C.

4. The battery processing method according to claim 1, characterized in that, In the first lithium deposition process, the pulse charging is performed using a high-rate pulse charging method.

5. The battery processing method according to claim 1, characterized in that, In the first lithium deposition process, the pulse charging is performed at a pulse charging frequency of 0.1Hz to 100Hz.

6. The battery processing method according to claim 1, characterized in that, It also includes a second lithium deposition process: after the first lithium deposition process, the lithium-ion battery is discharged at least once, followed by a pulse charge to deposit lithium on the negative electrode material.

7. The battery processing method according to claim 1, characterized in that, Also includes: At least a battery disassembly process for disassembling the negative electrode material from the lithium-ion battery; and The lithium extraction process for extracting lithium from the negative electrode material.

8. The battery processing method according to claim 1, characterized in that, In the first lithium deposition process, the pulse charging is performed intermittently with a specified voltage and current by a charging device that adjusts the voltage and current.

9. The battery processing method according to claim 1, characterized in that, The lithium-ion battery is formed by stacking the positive electrode material and the negative electrode material along the stacking direction. In the first lithium deposition process, the lithium-ion battery is cooled by a cooling device, which is arranged in pairs on both sides of the lithium-ion battery in the stacking direction.

10. The battery processing method according to claim 9, characterized in that, The cooling device has a central cooling element pair for cooling the central portion of the lithium-ion battery and a pair of side cooling elements for cooling the two sides of the lithium-ion battery.

11. The battery processing method according to claim 4, characterized in that, The high-rate charging refers to charging with a current greater than that required to fully charge the lithium-ion battery in two hours.

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