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, the method including: a first step in which the lithium ion battery is charged while being cooled, and lithium is deposited in the negative electrode material; a second step for raising the temperature of the lithium ion battery; and a third step in which the lithium ion battery is charged while being cooled again and lithium is deposited in the negative electrode material.

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] One aspect of the present invention provides a battery processing method for processing a lithium-ion battery containing a positive electrode material and a negative electrode material, comprising:

[0012] A first step in which lithium is deposited on the negative electrode material while the lithium-ion battery is being cooled and charged.

[0013] The second step of returning the lithium-ion battery to room temperature; and

[0014] The third step involves charging the lithium-ion battery while it is being cooled again, thereby depositing lithium on the negative electrode material.

[0015] The effects of the invention

[0016] According to the present invention, lithium can be efficiently recovered from the negative electrode of a lithium-ion battery. Attached Figure Description

[0017] Figure 1 This is a block diagram schematically representing the recycling system involved in the first embodiment.

[0018] Figure 2 This is a three-dimensional diagram showing the general structure of a lithium-ion battery.

[0019] Figure 3 It is a cross-sectional view showing the general structure of a single battery cell.

[0020] Figure 4 It is a flowchart that roughly represents the process of reusing lithium-ion batteries.

[0021] Figure 5 This is a schematic diagram that represents an example of the cooling device according to the first embodiment.

[0022] 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.

[0023] Symbol Explanation

[0024] 1 Lithium-ion battery

[0025] 3 battery cells

[0026] 4 battery components

[0027] 10 Reuse Department

[0028] 12 charging devices

[0029] 20 Recycling Department

[0030] 21 Dismantling Device

[0031] 22 Extraction device

[0032] 23 Recycling Unit

[0033] 31 Cathode Material

[0034] 34 partitions

[0035] 35 Anode Material

[0036] 38-layer stacked electrode body

[0037] 39 Electrolyte

[0038] 40 housing

[0039] 200 Reuse System

[0040] 201 Cooling and heating device. Detailed Implementation

[0041] 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 have completed a battery processing method capable of efficiently recovering lithium from lithium-ion batteries.

[0042] A method for reusing lithium-ion batteries according to one embodiment of the present invention.

[0043] This is a battery processing method for processing lithium-ion batteries containing positive electrode materials and negative electrode materials, comprising:

[0044] A first step in which lithium is deposited on the negative electrode material while the lithium-ion battery is being cooled and charged.

[0045] The second step of returning the lithium-ion battery to room temperature; and

[0046] The third step involves charging the lithium-ion battery while it is being cooled again, thereby depositing lithium on the negative electrode material.

[0047] [First Implementation Method]

[0048] 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 the 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.

[0049] 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.

[0050] 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 and heating device 201. The charging device 12 is configured to charge the lithium-ion battery 1 in any charging mode by adjusting the voltage and current. For example, it can continuously charge the lithium-ion battery 1 with a specified voltage and current, and it can 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.

[0051] 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.

[0052] Figure 2 This diagram schematically represents 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.

[0053] 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."

[0054] 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.

[0055] In this embodiment, the stacked electrode body 38 is composed of multiple sets of positive electrode material 31, separator 34 and negative electrode material 35 stacked in the stacking direction A. Viewed from the stacking direction A, the battery cell 3 has a slender rectangular shape in the width direction B.

[0056] The positive electrode material 31 has a positive current collector 32 and a positive active material 33 disposed 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).

[0057] The negative electrode material 35 has 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. 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.

[0058] 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.

[0059] 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.

[0060] 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.

[0061] 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.

[0062] 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 unsuitable for use in the electric vehicle based on, for example, the State of Health (SOH), a recycling process (step S1) is performed. In the recycling process S1, the lithium-ion battery 1 is removed from the electric vehicle and reused in the recycling unit 10.

[0063] When the lithium-ion battery 1 is used as a storage device for secondary use and is determined to be in a specified deterioration state, it is then reused in the recycling unit 10, where a lithium deposition process (step S2) is performed. 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 charged to deposit lithium on the negative electrode material 35. The lithium deposition process S2 includes:

[0064] The first process involves cooling the lithium-ion battery 1 while charging it, and depositing lithium on the negative electrode material 35.

[0065] The second process of heating up lithium-ion battery 1; and

[0066] The third step involves charging the lithium-ion battery 1 while it is being cooled again, and lithium is deposited on the negative electrode material 35.

[0067] Figure 5 This is a schematic diagram showing the cooling and heating device 201. Figure 5 In the text, the battery cell 3, which is cooled or heated by a cooling and heating device, is shown in a general sense. For example... Figure 5 As shown, the cooling and heating devices 201 are arranged in pairs on both sides of the stacking direction A of the battery cell 3. Alternatively, one side of each pair of cooling and heating devices 201 can also be arranged such that a single cooling and heating element covers the entire width direction B of the battery cell 3, as shown. Figure 5As shown, the battery cell 3 can also be divided into multiple sets of cooling and heating elements 202 along the width direction B. In this embodiment, it has a central cooling and heating element pair 202A for cooling the central portion 3a of the battery cell 3, and a side cooling and heating element pair 202B and a side cooling and heating element pair 202C for cooling the two side portions 3b and 3c of the battery cell 3. Figure 5 As 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 and heating elements 202 are divided, they are not limited to being divided into three groups; they can also be divided into two or more groups. For example, by cooling the battery cell 3 using only the central cooling and heating element 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 and heating 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).

[0068] The cooling and heating device 201 is not limited and can be any type of cooling and heating device. For example, a constant temperature bath can be used as the cooling and heating device 201. Alternatively, the cooling and heating device 201 can be a separate device that includes both a cooling device and a heating device. Alternatively, for example, cooling can be performed in a constant temperature bath and heating can be performed in an oven.

[0069] In the first process, the lithium-ion battery 1 is cooled and charged simultaneously under specified cooling conditions by the cooling and heating device 201. Figure 6 The graph shows the relationship between the charging rate relative to SOC (State of Charge) and the ease of lithium deposition at each temperature. 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.

[0070] Therefore, in the first process, the lithium-ion battery 1 is charged in the negative electrode material 35 according to the charging rate of lithium deposition and the cooling temperature.

[0071] The cooling temperature varies depending on the operating environment and type of the lithium-ion battery 1. However, 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 -50°C or above -40°C. In one embodiment, the cooling temperature can be from -40°C to 10°C.

[0072] The cooling rate can be, for example, from 0.1°C / min to 10°C / min. From the viewpoint of reducing the non-uniformity of lithium deposition sites, the cooling rate is preferably from 1°C / min to 10°C / min. Furthermore, in this invention, "cooling rate" and "heating rate" are parameters based on the internal temperature of the battery, not the ambient temperature.

[0073] Therefore, in the first process, the lithium-ion battery 1 is charged while being cooled.

[0074] As a result, even without high-rate charging, lithium can be deposited in a portion of the negative electrode material 35, which can suppress the charging current and thus save energy.

[0075] Here, in the lithium deposition process S2, charging can be performed as long as the lithium-ion battery 1 is in a cooled state. The cooling of the lithium-ion battery 1 by the cooling and heating device 201 and the charging of the lithium-ion battery 1 by the charging device 12 can start simultaneously, or either one can start first. That is, after the cooling performed by the cooling and heating device 201 is performed, the charging device 12 can be used to charge the battery while maintaining the cooled state performed by the cooling and heating device 201.

[0076] On the other hand, in the first process, if the charging performed while only a portion of the lithium-ion battery 1 is cooled is not a high-rate charge, there is a concern that lithium deposition in the cooled portion could be suppressed by performing a normal charging reaction in the non-cooled portion. Therefore, charging can also be performed at a high rate.

[0077] Furthermore, in this specification, high-rate charging refers to charging in which a large current of lithium is intentionally generated in the negative electrode material 35 during charging.

[0078] For example, when the lithium-ion battery 1 is a capacity-type battery, it is preferable to charge it 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 charge it 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 charging at a high rate and by continuously charging within a specified time, lithium can be deposited more efficiently on the negative electrode material 35.

[0079] 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.

[0080] If the charging current is too high due to high-rate charging, undesirable side reactions may occur, such as electrolyte vaporization due to heat generation, deformation and damage to various components. From an energy-saving perspective, excessive charging current is also undesirable. For example, when the lithium-ion battery 1 is a capacity-type battery, it is preferable to set the upper limit of the charging current to around 3C. On the other hand, when the lithium-ion battery 1 is a high-output type battery, it is preferable to set the upper limit of the charging current to around 20C.

[0081] Next, in the second step, the lithium-ion battery 1 is heated to a predetermined temperature by the cooling and heating device 201. In the first step, the lithium deposited in the negative electrode material 35 is ionized by the heating and absorbed by the negative electrode active material 37 (e.g., graphite) in the negative electrode material 35. At this time, due to the decrease in viscosity of the electrolyte 39 and the increase in the mobility of lithium ions associated with the heating, a larger portion of the negative electrode active material 37 is preferentially absorbed by lithium ions. Therefore, after the second step, a portion of the negative electrode active material 37 can be in a state where it has absorbed a greater amount of lithium ions than before the first step.

[0082] In the second step, it is preferable to raise the temperature to room temperature. Furthermore, in this specification, room temperature refers to a temperature within the range of 5°C to 35°C. Therefore, in the second step, the lithium-ion battery 1 can be heated to 5°C to 35°C, preferably to 15°C to 25°C.

[0083] In the second step, the temperature can be increased by placing the lithium-ion battery 1 in a room temperature environment for a certain period of time, or by heating. There is no particular limitation on the heating method, and it can be carried out by known methods such as hot water baths or ovens.

[0084] The heating rate can be, for example, from 0.1°C / min to 20°C / min. From the viewpoint of reducing the inhomogeneity of the final lithium deposition site, the heating rate is preferably from 1°C / min to 10°C / min.

[0085] Furthermore, in the second step, heating can be performed simultaneously with discharging. By discharging while heating, the efficiency of charging in the subsequent third step can be improved. At this time, the discharge rate is not particularly limited; for example, it can be discharged at the same rate as charging in the first step. Also, discharging is not limited to occurring simultaneously with heating; for example, discharging can be performed first in the second step followed by heating, or discharging can be performed after heating. From the viewpoint of enabling the normal discharge reaction in the lithium-ion battery 1 to occur, discharging simultaneously with or after heating is preferable.

[0086] Next, in the third process, the lithium-ion battery 1 is cooled again while being charged, and lithium is deposited on the negative electrode material 35.

[0087] The charging and cooling conditions in the third process can be any of the conditions listed in the first process. Alternatively, the charging and cooling conditions in the third process can be set differently from those in the first process, depending on the battery's degradation state and the lithium-ion absorption state in the negative electrode active material 37. For example, in the third process, from the viewpoint of precipitating more lithium than in the first process, the cooling temperature can be 1°C, 2°C, 3°C, 5°C, 7°C, or 10°C lower than in the first process.

[0088] Since the portion of the negative electrode active material 37 that absorbed more lithium at the end of the second process is cooled in the third process, the amount of lithium deposited in this portion of the negative electrode active material 37 at the end of the third process is greater than the amount of lithium deposited at the end of the first process. Therefore, through the above-described first to third processes, lithium can be deposited in the entire negative electrode material 35 while a portion of the negative electrode material 35 has a greater amount of lithium deposited than other portions.

[0089] Next, the lithium-ion battery 1 is removed from the recycling section 10 and subjected to a battery dismantling process (step S3) using the dismantling device 21. 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 manually dismantled using tools or the like without using the dismantling device 21.

[0090] Next, a lithium extraction process (step S4) is performed to extract lithium from the disassembled negative electrode material 35. In the lithium extraction process, the negative electrode material 35 is filtered after being percolated with water to remove the negative electrode current collector 36 and the negative electrode active material 37 from the negative electrode material 35, and an aqueous solution containing lithium ions is extracted.

[0091] Furthermore, by selectively supplying the portion of the disassembled negative electrode material 35 that has a higher lithium deposition rate than other portions in the third step of the lithium deposition process S2 to the lithium extraction process S4, lithium can be extracted efficiently.

[0092] Finally, a lithium recovery process (step S5) is performed to recover lithium from an aqueous solution containing lithium ions. In the lithium recovery process, after the lithium is soluble in carbonated water, it is recovered as lithium carbonate by filtration.

[0093] As a result, the negative electrode material 35 is typically constructed by layering graphite in the form of current collector foil, such as copper, and therefore contains fewer valuable substances compared to the positive electrode material 31, which contains multiple valuable substances such as cobalt, nickel, and manganese. Therefore, unlike the staged extraction of multiple valuable metals required when recovering lithium from the positive electrode material 31, lithium can be recovered from the negative electrode material 35 efficiently.

[0094] 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.

[0095] [Second Implementation]

[0096] In the second embodiment, the difference lies in the use of a second lithium deposition process S12 instead of the lithium deposition process S2 involved in the first embodiment. The second lithium deposition process S12 includes the first to third processes in the same way as the lithium deposition process S2, and also includes the following fourth process: after the third process, the process of heating the lithium-ion battery to room temperature and then charging while cooling is repeated at least once to deposit lithium on the negative electrode material.

[0097] In the fourth step, heating, cooling, and charging can be performed under the same conditions as those listed in the first to third steps. Furthermore, similar to the second step, discharging can be performed while heating is in progress. Additionally, during heating, discharging can be performed either during or before / after heating, similar to the second step.

[0098] In the fourth process, heating, cooling, and charging are performed at least once. From the viewpoint of ensuring that more lithium is deposited in the negative electrode material 35 after the fourth process, the number of repetitions of heating, cooling, and 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 heating, cooling, and charging increases, the amount of lithium ions that the negative electrode active material 37 can absorb during heating converges to a certain value; therefore, excessive repetitions 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.

[0099] Through the heating in the fourth process, the re-ionized lithium is absorbed in the region (active region) of the negative electrode active material 37 where there is still capacity for lithium ion absorption. By subsequently 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, thus 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 fourth process, more lithium can be deposited in the negative electrode material 35 compared to only performing the third process.

[0100] Furthermore, by selectively supplying the portion of the disassembled negative electrode material 35 that has a higher lithium deposition rate than other portions in the third or fourth step of the lithium deposition step S2 to the lithium extraction step S4, lithium can be extracted efficiently.

[0101] In the second embodiment described above, the case where the lithium-ion battery 1 is provided to the recycling process S1 as a single cell 3, followed by the implementation of the second lithium deposition process S12, has been used as an example, but the method is not limited to this. In the recycling process S1 and / or the second lithium deposition process S12, the lithium-ion battery 1 may also be provided as a battery pack or battery assembly 4. In this case, a cooling and heating device 201 may be pre-installed inside the battery pack or battery assembly 4.

[0102] 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.

[0103] 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.

[0104] Although described on a per-unit basis, it can also be implemented on a per-module basis or a per-battery pack basis. In the case of implementation on a per-battery pack basis, pressing devices, cooling devices, etc., can also be pre-installed inside the battery pack.

[0105] [Postscript]

[0106] The lithium-ion battery 1 recycling system 200 according to the present invention provides the following method.

[0107] [Method 1]

[0108] A battery processing method is a battery processing method for processing lithium-ion batteries containing positive electrode materials and negative electrode materials, comprising:

[0109] A first step in which lithium is deposited on the negative electrode material while the lithium-ion battery is being cooled and charged.

[0110] The second step of heating the lithium-ion battery; and

[0111] The third step involves charging the lithium-ion battery while it is being cooled again, thereby depositing lithium on the negative electrode material.

[0112] [Method 2]

[0113] According to the battery processing method described in Method 1,

[0114] In the first step and / or the third step, cooling is performed at a rate of 0.1°C / min to 10°C / min.

[0115] [Method 3]

[0116] According to the battery processing method described in method 1 or 2,

[0117] In the second step, the temperature is increased by heating.

[0118] [Method 4]

[0119] According to the battery processing method described in Method 3,

[0120] In the second process, the temperature is increased at a rate of 0.1℃ / min to 20℃ / min.

[0121] [Method 5]

[0122] According to any one of the battery processing methods described in methods 1 to 4

[0123] In the second process, the temperature is increased while the discharge is carried out.

[0124] [Method 6]

[0125] According to any one of the battery processing methods described in methods 1 to 5

[0126] In the first step and / or the third step, charging is performed by high-rate charging.

[0127] [Method 7]

[0128] According to any one of the battery processing methods described in methods 1 to 6,

[0129] It also includes the following fourth step: after the third step, the process of heating the lithium-ion battery to a specified temperature and then charging it while cooling is repeated at least once to deposit lithium on the negative electrode material.

[0130] [Method 8]

[0131] The battery processing method according to any one of methods 1 to 7 further includes:

[0132] At least a battery disassembly process for disassembling the negative electrode material from the lithium-ion battery; and

[0133] The lithium extraction process for extracting lithium from the negative electrode material.

[0134] [Method 9]

[0135] According to the battery processing method described in Method 8,

[0136] In the lithium extraction process, lithium is selectively extracted from the part of the negative electrode material where the lithium deposition is most abundant.

[0137] [Method 10]

[0138] A battery processing system is used to process lithium-ion batteries containing positive electrode materials and negative electrode materials, comprising:

[0139] A cooling device capable of cooling the lithium-ion battery and controlling its cooling and non-cooling states; and

[0140] A charging device that charges the battery.

[0141] [Method 11]

[0142] According to the battery processing system described in Method 10,

[0143] It also includes a heating device that can heat up the lithium-ion battery.

[0144] [Method 12]

[0145] According to the battery processing method described in Method 1,

[0146] The lithium-ion battery is formed by stacking the positive electrode material and the negative electrode material along the stacking direction.

[0147] In the first and third steps, 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.

[0148] [Method 13]

[0149] According to the battery processing method described in Method 12,

[0150] 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.

[0151] [Method 14]

[0152] According to the battery processing method described in Method 1,

[0153] In the second step, the lithium-ion battery is heated by placing it in a room temperature environment for a certain period of time.

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 step in which lithium is deposited on the negative electrode material while the lithium-ion battery is being cooled and charged. The second step of heating the lithium-ion battery; and The third step involves charging the lithium-ion battery while it is being cooled again, thereby depositing lithium on the negative electrode material.

2. The battery processing method according to claim 1, characterized in that, In the first step and / or the third step, cooling is performed at a rate of 0.1°C / min to 10°C / min.

3. The battery processing method according to claim 1, characterized in that, In the second step, the temperature is increased by heating.

4. The battery processing method according to claim 3, characterized in that, In the second process, the temperature is increased at a rate of 0.1℃ / min to 20℃ / min.

5. The battery processing method according to claim 1, characterized in that, In the second process, the temperature is increased while the discharge is carried out.

6. The battery processing method according to claim 1, characterized in that, In the first step and / or the third step, charging is performed by high-rate charging.

7. The battery processing method according to claim 1, characterized in that, It also includes the following fourth step: after the third step, the process of heating the lithium-ion battery to a specified temperature and then charging it while cooling is repeated at least once to deposit lithium on the negative electrode material.

8. 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.

9. The battery processing method according to claim 8, characterized in that, In the lithium extraction process, lithium is selectively extracted from the part of the negative electrode material where the lithium deposition is most abundant.

10. 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 and third steps, 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.

11. The battery processing method according to claim 10, 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.

12. The battery processing method according to claim 1, characterized in that, In the second step, the lithium-ion battery is heated by placing it in a room temperature environment for a certain period of time.

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