Battery processing method

Abstract

Provided is a battery processing method for efficiently recovering lithium from a lithium ion battery. A battery processing method for processing a lithium ion battery (1) including a positive electrode material (31) and a negative electrode material (35) includes a lithium deposition step (S2) for depositing lithium on the negative electrode material (35) by performing pulse charging on the lithium ion battery (1) while cooling, in which a charging stage (Fc) and a charging stop stage (Fs) are alternately performed during the pulse charging, and the charging stage (Fc) is performed at least multiple times, and in the charging stage (Fc), the charging stop stage (Fs) is performed at least multiple times, and in the charging stop stage (Fs), the charging stop stage (Fs) is performed at least multiple times. The lithium ion battery (1) is cooled.

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 materials, including lithium. Therefore, it is necessary to recycle these valuable materials from used lithium-ion batteries to achieve resource recycling.

[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 a used lithium-ion battery.

[0004] Existing technical documents

[0005] Patent documents

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

[0007] The problem that the invention aims to solve

[0008] Cathode materials are typically constructed by forming a positive electrode active material on a current-collecting foil such as aluminum. This positive electrode active material, for example in the case of a ternary (NMC) system, contains valuable elements such as nickel, manganese, and cobalt. To recover these valuable elements from the positive electrode active material, the material needs to be calcined together with a reducing agent, and after pulverization, the black powder containing the positive electrode active material is sorted. Next, the black powder undergoes staged solvent extraction, sequentially extracting manganese, cobalt, and nickel, and finally lithium. Therefore, lithium recovery, in particular, is very laborious. Summary of the Invention

[0009] The objective of this invention is to provide a battery processing method and system capable of efficiently recovering lithium from lithium-ion batteries.

[0010] One aspect of the present invention is a battery processing method for processing a lithium-ion battery comprising a positive electrode material and a negative electrode material, wherein,

[0011] The process includes a lithium deposition step, in which lithium is deposited on the negative electrode material by pulse charging of the lithium-ion battery under cooling.

[0012] In the pulse charging, charging phases and charging pause phases are alternately performed, and the charging phases are performed at least multiple times.

[0013] During the charging phase, the lithium-ion battery is cooled.

[0014] Another aspect of the present invention is a battery processing system for processing lithium-ion batteries containing positive electrode materials and negative electrode materials, comprising:

[0015] A charging device that performs pulse charging on the lithium-ion battery, the pulse charging having alternating charging phases and charging pause phases, and having at least multiple charging phases; and

[0016] A cooling device that cools the lithium-ion battery during the charging phase.

[0017] The effects of the invention

[0018] According to the present invention, lithium can be efficiently recovered from the negative electrode of a lithium-ion battery. Attached Figure Description

[0019] Figure 1 This is a block diagram schematically representing the recycling system involved in the first embodiment.

[0020] Figure 2 It is a three-dimensional diagram showing the general structure of a lithium-ion battery.

[0021] Figure 3 It is a cross-sectional view showing the approximate structure of a single battery cell.

[0022] Figure 4 It is a flowchart that roughly represents the process of reusing lithium-ion batteries.

[0023] Figure 5 This is a graph showing the relationship between the charge rate relative to the state of charge (SOC) and the ease of lithium deposition at each cooling temperature.

[0024] Figure 6 This is a schematic diagram illustrating pulse charging.

[0025] Figure 7 It is a block diagram schematically representing the reuse section involved in the modified example.

[0026] Figure 8A This is a schematic diagram illustrating the pulse charging involved in the modified example.

[0027] Figure 8B This is a schematic diagram illustrating the pulse charging involved in other variations.

[0028] Figure 9 This is a block diagram schematically illustrating the reuse system involved in the second embodiment.

[0029] Figure 10 This is a diagram showing the general structure of the pressing device.

[0030] Figure 11 This is a flowchart that schematically illustrates the reuse process involved in the fourth embodiment.

[0031] Figure 12A This is a diagram that roughly represents an example of the operation of a pressing device.

[0032] Figure 12B It is a general representation of the continuation Figure 12A A diagram illustrating an example of the operation of the subsequent pressing device.

[0033] Figure 13A These are diagrams that roughly represent other examples of the action of a pressing device.

[0034] Figure 13B It is a general representation of the continuation Figure 13A The following diagram shows other examples of the operation of the pressing device.

[0035] Figure 13C It is a general representation of the continuation Figure 13B The following diagram shows other examples of the operation of the pressing device.

[0036] Figure 14 This is a schematic diagram that represents an example of the cooling device according to the first embodiment.

[0037] Symbol Explanation

[0038] 1. Lithium-ion battery

[0039] 3. Battery cells

[0040] 4 Battery Modules

[0041] 10 Reuse Department

[0042] 12 charging devices

[0043] 20 Recycling Department

[0044] 21 Disassembly Device

[0045] 22 Extraction device

[0046] 23 Recycling Unit

[0047] 31 Cathode Material

[0048] 34 diaphragm

[0049] 35 Anode Material

[0050] 38-layer stacked electrode body

[0051] 39 Electrolyte

[0052] 40 housing

[0053] 100 Reuse System

[0054] 201 Cooling device

[0055] 301 Pressing device. Detailed Implementation

[0056] The inventors of this application conducted in-depth research to efficiently recover lithium from lithium-ion batteries and discovered that lithium can be efficiently recovered from lithium-ion batteries by intentionally inducing lithium deposition (e.g., dendrites) on the negative electrode material, which is undesirable in normal charging reactions. Based on this insight, the inventors of this application completed a battery processing method capable of efficiently recovering lithium from lithium-ion batteries.

[0057] One embodiment of the present invention relates to a lithium-ion battery recycling method, which is a battery processing method for processing lithium-ion batteries containing positive electrode materials and negative electrode materials, wherein...

[0058] The process includes a lithium deposition step, in which lithium is deposited on the negative electrode material by pulse charging of the lithium-ion battery under cooling.

[0059] In the pulse charging, charging phases and charging pause phases are alternately performed, and the charging phases are performed at least multiple times.

[0060] During the charging phase, the lithium-ion battery is cooled.

[0061] Furthermore, one embodiment of the present invention relates to a battery processing system for processing lithium-ion batteries, which is a battery processing system for processing lithium-ion batteries containing positive electrode materials and negative electrode materials, and includes:

[0062] A charging device that performs pulse charging on the lithium-ion battery, the pulse charging having alternating charging phases and charging pause phases, and having at least multiple charging phases; and

[0063] A cooling device that cools the lithium-ion battery during the charging phase.

[0064] [First Implementation Method]

[0065] 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 lithium-ion battery 1 recycling system 100. (See diagram for example.) Figure 1 As shown, the reuse system 100 includes: a reuse unit 10 for example, reusing a lithium-ion battery 1 that has been used once in an electric vehicle; and a recovery unit 20 for recovering lithium from the reused lithium-ion battery 1.

[0066] The reuse unit 10 reuses the previously used lithium-ion battery 1 as an energy storage device. Generally, the degradation state of lithium-ion batteries used in electric vehicles is determined based on their State of Health (SOH), which indicates the capacity of the battery when fully charged 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 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 storing renewable energy sources like solar and wind power, or as a backup power source during disasters. For example, if the SOH is below 70%, it can be determined that it is unsuitable for primary use, i.e., unsuitable for use in an electric vehicle.

[0067] The reuse unit 10 includes a lithium-ion battery 1 that is reused as an energy storage device, and a charging device 12. 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 charge the lithium-ion battery 1 continuously with a specified voltage and current, or it can charge it intermittently 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.

[0068] The recycling unit 10 also includes a cooling device 201 capable of cooling the lithium-ion battery 1. The type of cooling device 201 is not limited; it can be any type of cooling device. In this embodiment, a constant temperature bath is used as the cooling device 201. For example, the cooling device 201 can also be configured as a cooling chamber capable of internal cooling, and the lithium-ion battery 1 can be cooled by housing it within the cooling chamber. Figure 14 As shown, however, the cooling devices 201 are arranged in pairs on both sides of the stacking direction A of the battery cells 3.

[0069] The recycling unit 20 includes: a dismantling device 21, which dismantles the lithium-ion battery 1 into positive electrode material 31 and negative electrode material 35, etc., through a lithium deposition process described later, when the lithium-ion battery 1 is determined, for example, to be unsuitable for secondary use based on the state of oxygen (SOH); an extraction device 22, which extracts lithium from the dismantled negative electrode material 35; and a recycling device 23, which recovers the extracted lithium. For example, it can be determined that the battery cannot be suitable for secondary use when the SOH is below 40%.

[0070] Figure 2This diagram schematically illustrates a lithium-ion battery 1 mounted in an electric vehicle. The lithium-ion battery 1 constitutes a battery pack, in which battery modules 4 integrate functions such as charging and discharging circuits and cooling mechanisms, and multiple battery modules 4 are interconnected and housed within a casing. The battery modules 4 are constructed by connecting multiple individual battery cells 3 in series or parallel, and are adjusted to the desired capacity and voltage.

[0071] Lithium-ion battery 1 is a rechargeable lithium-ion secondary battery. In this specification, unless otherwise specified, the term lithium-ion battery may be used collectively to refer to battery cell, battery module, and battery pack.

[0072] 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 laminated type. The battery cell 3 has a laminated electrode body 38 formed by sequentially stacking a positive electrode material 31, a separator 34, and a negative electrode material 35 in the stacking direction A; and a housing 40 that houses the laminated electrode body 38.

[0073] In this embodiment, the stacked electrode body 38 is composed of multiple sets of positive electrode materials 31, separators 34, and negative electrode materials 35 stacked in the stacking direction A. When viewed from the stacking direction A, the battery cell 3 has an elongated rectangular shape in the width direction B.

[0074] The positive electrode material 31 has 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. One end of the plurality of positive electrode current collectors 32 in the width direction B perpendicular to the stacking direction (at...) Figure 3 The cathode (left side) has interconnected positive current collector ends 32a. The positive current collector 32 can preferably be a metal foil suitable for the positive electrode. The positive active material 33 can be a material used as a positive active material in lithium-ion secondary batteries. In this embodiment, the positive current collector 32 is made of aluminum, and the positive active material 33 is made of NMC (nickel, manganese, cobalt).

[0075] 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 other end of the plurality of negative electrode current collectors 36 in the width direction B (at...) Figure 3 The negative electrode current collector 36a (located on the right side) is interconnected with the negative electrode current collector. The negative electrode current collector 36 can preferably be 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.

[0076] Both 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 hexafluorophosphate (LiPF6) at a concentration of 1 mol / L.

[0077] A separator 34 is disposed between the positive electrode material 31 and the negative electrode material 35, physically and electrically separating the two. The separator 34 can be a porous body having multiple tiny pores through which lithium ions can pass. In this embodiment, the separator 34 is a porous membrane made of polyolefin.

[0078] The housing 40 has a pair of first housings 41 and second housings 42 disposed on both sides of the stacking direction A of the stacked electrode body 38. The first housings 41 and second housings 42 are formed with 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 bulging away from the second housing 42 in the stacking direction A. Similarly, the second housing 42 has a pair of flange portions 42a and a main body portion 42b bulging away from the first housing 41.

[0079] The first housing 41 and the second housing 42 are joined together, with the positive current collector end 32a and the negative current collector end 36a sandwiched between their respective flange portions 41a and 42a, thereby forming the housing 40. That is, with the stacked electrode body 38 housed in the housing 40, the positive current collector end 32a and the negative current collector end 36a are sandwiched between a pair of flange portions 41a and 42a, and the remaining portion of the stacked electrode body 38 is housed in the 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 by a pair of main body portions 41b and 42b with a predetermined pressure in the stacking direction A. In the battery cell 3, the portion sandwiched by a pair of flange portions 41a and 42a constitutes an example of the tab 43 involved in the present invention.

[0080] 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 an electric vehicle is determined to be in a deteriorated state unsuitable for use in an electric vehicle based on, for example, SOH (State of Health), 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.

[0081] After the lithium-ion battery 1 is used as an energy storage device for secondary use, if it is determined to be in a specified deterioration state, a lithium deposition process (step S2) is performed in the recycling unit 10 after secondary use. 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.

[0082] In the lithium deposition process S2, the lithium-ion battery 1 is cooled by the cooling device 201 under specified cooling conditions and then charged. Here, Figure 5 The graph shows the relationship between SOC (State of Charge) and the charging rate (charging current) at which lithium begins to deposit at each temperature. Specifically, lithium readily deposits on the negative electrode material 35 when charging is performed on the curves at each temperature and in the region above those curves. SOC is an indicator of the battery's state of charge, representing the battery capacity when fully charged (100%) and fully discharged (0%). Figure 5 As shown, the higher the SOC and / or the lower the temperature of lithium-ion battery 1, the easier it is for lithium to be deposited.

[0083] Therefore, in the lithium deposition process S2, the current rate (also called the charge rate) Ch for lithium deposition is set relative to the cooling temperature (refer to...). Figure 6 The lithium-ion battery 1 is charged. Let the charging current rate during normal use be Cn (refer to...). Figure 6 In the lithium deposition process S2, the current rate Ch is greater than or equal to the current rate Cn. For example, the lithium-ion battery 1 can be charged at the current rate at which lithium deposition begins, which allows for more energy-efficient deposition of lithium on the negative electrode material 35. For example, by cooling the lithium-ion battery 1, lithium can be deposited on the negative electrode material 35 even with a low charging rate.

[0084] As for the charging method in the lithium deposition process S2, intermittent pulse charging is adopted. Specifically, such as... Figure 6 As shown, pulse charging includes a charging phase Fc in which lithium is deposited, and a charging pause phase Fs in which the charging is stopped, and these phases are repeated multiple times. At least the charging phase Fc is performed multiple times. In addition, preferably, cooling based on the cooling device 201 is performed only in the charging phase Fc and not in the charging pause phase Fs.

[0085] Here, as lithium is deposited on the negative electrode material 35, the number of lithium ions present in the vicinity of the negative electrode active material 37 (at least in the region adjacent to the negative electrode active material) decreases. As a result, the lithium ion concentration in the electrolyte 39 decreases near the negative electrode active material 37, making it difficult to effectively deposit lithium on the negative electrode material 35 even with continued charging. Therefore, according to this embodiment, during the charging pause phase Fs of pulse charging, lithium ions around the negative electrode active material 37 tend to accumulate near the negative electrode active material 37, which can alleviate the decrease in lithium ion concentration near the negative electrode active material 37. Therefore, after the decrease in lithium ion concentration is alleviated, lithium can be effectively deposited on the negative electrode material 35 by performing the charging phase Fc.

[0086] For example, the charging phase Fc is performed until the lithium ion concentration in the electrolyte 39 near the negative electrode active material 37 falls below a first concentration, for example, for 30 seconds. The first concentration is the concentration at which lithium is difficult to deposit on the negative electrode material 35. The charging pause phase Fs is performed until the lithium ion concentration in the electrolyte 39 near the negative electrode active material 37 reaches a second concentration or higher, for example, for 30 seconds. The second concentration is the concentration at which lithium is easily deposited on the negative electrode material 35.

[0087] Next, the lithium-ion battery 1 is removed from the recycling section 10, and the battery disassembly process (step S3) is performed by the disassembly device 21. In the battery disassembly process S3, the lithium-ion battery 1 is broken down 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 planned to be recycled, at least the negative electrode material 35 can be disassembled. The disassembly device 21 can be any device capable of automatically disassembling the lithium-ion battery 1. Alternatively, the lithium-ion battery 1 can be manually disassembled using tools or the like without using the disassembly device 21.

[0088] Next, a lithium extraction process (step S4) is performed. In the lithium extraction process S4, lithium is extracted from the disassembled negative electrode material 35. In the lithium extraction process S4, the negative electrode material 35 is leached with water by 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.

[0089] Finally, the lithium recovery process (step S5) is implemented. In the lithium recovery process S5, lithium is recovered from an aqueous solution containing lithium ions. In the lithium recovery process S5, the lithium is soluble in carbonated water by the recovery device 23, and then filtered to recover lithium as lithium carbonate.

[0090] That is, the battery processing method involved in this embodiment is a battery processing method for processing a lithium-ion battery 1 containing a positive electrode material 31 and a negative electrode material 35, including a lithium deposition step S2, wherein lithium is deposited on the negative electrode material 35 by pulse charging of the lithium-ion battery 1 under cooling, wherein a charging phase Fc and a charging rest phase Fs are alternately performed in the pulse charging, and at least the charging phase Fc is performed multiple times, wherein the lithium-ion battery 1 is cooled in the charging phase Fc.

[0091] Furthermore, the recycling system (battery processing system) 100 according to this embodiment is a battery processing system for processing a lithium-ion battery 1 containing a positive electrode material 31 and a negative electrode material 35, and includes: a charging device 12 that performs pulse charging on the lithium-ion battery 1, the pulse charging having alternating charging phases Fc and charging pause phases Fs, and having at least multiple charging phases; and a cooling device 201 that cools the lithium-ion battery 1 during the charging phase.

[0092] As a result, lithium can be deposited on the negative electrode material 35 without high-rate charging by charging under cooling conditions. Therefore, the charging current can be suppressed, thereby saving energy.

[0093] Furthermore, during the charging pause phase in pulse charging, the decrease in lithium-ion concentration near the negative electrode active material 37 is mitigated. Therefore, the decrease in lithium-ion concentration near the negative electrode active material 37 caused by lithium deposition on the negative electrode material 35 during the charging phase is alleviated during the charging pause phase, thus facilitating effective lithium deposition on the negative electrode material 35 in subsequent charging phases. Compared to continuous charging, intermittent charging via pulse charging allows for more effective lithium deposition on the negative electrode material 35.

[0094] Furthermore, cooling of the lithium-ion battery 1 is only implemented during the charging phase. In other words, cooling of the lithium-ion battery 1 ceases during the charging pause phase.

[0095] As a result, by halting cooling during the charging pause phase, the electrolyte 39 is difficult to maintain at a low temperature, thus suppressing the decrease in viscosity of the electrolyte 39. Consequently, lithium ions in the electrolyte 39 become more mobile, thus facilitating their movement towards the vicinity of the negative electrode active material 37. Therefore, it is easier to mitigate the decrease in lithium ion concentration at the negative electrode active material 37.

[0096] Figure 7This refers to the recycling section 110 involved in the modified example. In the modified example, the recycling section 110 also includes a discharge device 111. The discharge device 111 discharges the lithium-ion battery 1 with a predetermined voltage and current. By including the discharge device 111, the lithium-ion battery 1 can also be discharged during the charging pause phase Fs. In other words, the charging pause phase Fs can also be configured as a discharge phase Fd. Other examples of providing the discharge phase Fd include, for example... Figure 8A As shown, a discharge phase Fd can be added between the charging phase Fc and the charging pause phase Fs, or as... Figure 8B As shown, a discharge phase Fd can be added during the charging rest phase Fs.

[0097] By adding a discharge stage Fd, lithium ions are actively attracted to the negative electrode active material 37, making it easier for them to move to the vicinity. As a result, the lithium ion concentration near the negative electrode active material 37 is easily increased, thus making it easier to deposit lithium more efficiently on the negative electrode material 35 during the subsequent charging stage Fc.

[0098] In the above embodiments, although the type of lithium-ion battery 1 is not specifically limited, it is preferable that the lithium-ion battery 1 is more of a high-output type (also known as a power type) than a capacity type (also known as an energy type). Compared with the capacity type lithium-ion battery, the high-output type lithium-ion battery has a lower density of negative electrode active material 37, thus exhibiting better adsorption of lithium ions into the negative electrode active material 37. Therefore, during the charging pause phase Fs in pulse charging, lithium ions can be more efficiently absorbed into the negative electrode active material 37, thereby making it easier to more efficiently deposit lithium on the negative electrode material 35 during the subsequent charging phase Fc. That is, when the lithium-ion battery 1 is a high-output type, the effects of the present invention can be more appropriately exerted.

[0099] In this specification, "high-output type" of lithium-ion battery 1 refers to an output density of 4000 kW / L or higher. On the other hand, "capacity type" of lithium-ion battery 1 refers to an energy density of 600 Wh / L or higher.

[0100] In the above embodiment, the example described is the case where the lithium-ion battery 1 is supplied to the recycling process S1 in the form of a battery pack, followed by the lithium deposition process S2, but it is not limited to this. The lithium-ion battery 1 may also be supplied to the recycling process S1 and / or the lithium deposition process S2 in the form of a battery module 4 or a battery cell 3.

[0101] [Second Implementation]

[0102] In the second embodiment, a second lithium deposition process S12 is used instead of the lithium deposition process S2 involved in the first embodiment (see reference). Figure 4This is different. In the second lithium deposition process S12, based on the lithium deposition process S2, during pulse charging, the lithium-ion battery 1 is also pressed in the stacking direction A under specified pressing conditions.

[0103] Figure 9 This is a block diagram schematically illustrating the reuse system 300 according to the second embodiment. For example... Figure 9 As shown, the reuse system 300 differs from the reuse system 100 of the first embodiment in that the lithium-ion battery 1 is supplied to the reuse unit 10 in the form of a battery cell 3 and the reuse unit 10 is equipped with a pressing device 301 for pressing the battery cell 3 in the stacking direction A.

[0104] In the second embodiment, it can be envisioned that the degradation of the lithium-ion battery 1 has not progressed significantly, and the electrolyte 39 is distributed throughout the battery cell 3.

[0105] The pressing device 301 is a device that presses the battery cell 3 in the stacking direction A with a predetermined pressing force. The pressing device 301 can be a device for a primary lithium-ion battery 1 installed in an electric vehicle to initiate a charge-discharge reaction within the lithium-ion battery 1, or it can be a device for a secondary lithium-ion battery 1 installed in the recycling section 10. Alternatively, a pressing device capable of automatically or manually adjusting the pressing force can also be provided separately. There are no particular limitations on the pressing device 301, and any actuator such as a hydraulic cylinder or a pneumatic cylinder can be used.

[0106] Figure 10 This is a schematic diagram of the pressing device 301. Figure 10 The image also schematically shows the battery cell 3 being pressed by the pressing device 301. (For example...) Figure 10 As shown, the battery cell 3 has multiple sets of pressing element pairs 302 divided along the width direction B, and each set of pressing element pairs 302 is arranged in pairs on both sides along the stacking direction A of the battery cell 3. In this embodiment, it has: a central pressing element pair 302A located at the center of the width direction B; and a pressing element pair 302A located on one side of the width direction B (in... Figure 10 The pressing element on one side (left side) of 302B; and the pressing element on the other side (in the width direction B) of 302B. Figure 10 The pressing element pair 302C is located on the other side of the middle (right side). The pressing element pair 302 is not limited to three sets; it can also be divided into two or more sets. Additionally, in... Figure 10 In the middle, the electrode portion located in the area enclosed by the dotted line and the side of the battery cell 3 is the central part 3a, and the electrode portions outside this area are the remaining parts, namely the two side parts 3b and 3c.

[0107] In the second lithium deposition process S12, the battery cell 3 is charged while partially pressed by activating at least a portion of the multiple sets of pressing elements 302. Therefore, in the second lithium deposition process S12, charging is performed while increasing the pressing force in the stacking direction A relative to the remaining portion of at least a portion of the battery cell 3. Typically, in order to initiate a charge-discharge reaction within the lithium-ion battery 1, it is necessary to press (i.e., constrain) the battery cell 3 in the stacking direction. In the second lithium deposition process S12, the battery cell 3 is pressed at least by the pressing force required to initiate this charge-discharge reaction. For example, this pressing force is 10 kPa or more and 1 MPa or less.

[0108] As a result, in addition to the effects of pulse charging under cooling, the following effects are also achieved: When charging the lithium-ion battery 1, by increasing the pressing pressure at least in a certain area, a (concentrated) charging reaction can be promoted at the corresponding negative electrode material 35. Consequently, the charging current is concentrated at the site where the charging reaction is promoted, resulting in high-rate charging locally and facilitating localized lithium deposition. For example, charging can be performed while sequentially changing the locations where the pressing pressure is increased, thereby causing lithium to deposit on the entire surface of the negative electrode material 35. Furthermore, by increasing the pressing pressure at the sites with residual electrolyte, lithium can be efficiently deposited at these sites.

[0109] "Increasing the pressing force in the stacking direction A relative to at least a portion of the remaining portion" also includes the case where the pressing force at the remaining portion is reduced while the entire battery cell 3 is being uniformly pressed. For example, in the lithium-ion battery 1 that is being reused in the recycling section 10 and is uniformly pressed as a whole, partially reducing or releasing the pressing force is also included in the second lithium deposition process S12. In this way, when the second lithium deposition process S12 is performed using the pressing device provided on the reused lithium-ion battery 1, compared to the case where the pressing device is separately installed on the lithium-ion battery 1 to perform the second lithium deposition process S12, the installation is not troublesome, and the operation can be more efficient.

[0110] Here, in the second lithium deposition process S12, the lithium-ion battery 1 can be charged as long as it is in a pressed state. The pressing of the lithium-ion battery 1 by the pressing device 301 and the charging of the lithium-ion battery 1 by the charging device 12 can start simultaneously, or one of them can start first. That is, after the pressing based on the pressing device 301 is performed, the charging based on the charging device 12 can be performed while maintaining the pressing state based on the pressing device 301.

[0111] Furthermore, in the lithium extraction step S4, lithium is selectively extracted from the portion of the disassembled negative electrode material 35 from which lithium was partially deposited in the second lithium deposition step S12. That is, lithium is selectively extracted from the portion of the negative electrode material 35 corresponding to the portion pressed during the second lithium deposition step S12. Which portion corresponds to this step among the disassembled multiple negative electrode materials 35 can be determined visually or based on the portion pressed during the second lithium deposition step S12. This allows for more efficient lithium extraction.

[0112] In the above embodiment, the case in which the pressing element 302 is divided in the width direction B of the battery cell 3 is described as an example. However, it can also be divided in the height direction C, which is orthogonal to the stacking direction A and the width direction B of the battery cell 3. It can also be divided in both the width direction B and the height direction C at the same time.

[0113] [Third Implementation Method]

[0114] In the third embodiment, a third lithium deposition process S13 is used instead of the lithium deposition process S2 involved in the first embodiment (see reference). Figure 4 This is different. In the third lithium deposition process S13, based on the lithium deposition process S2, the battery cell 3 is pressed in the stacking direction A at the center of the width direction B and / or height direction C under specified pressing conditions, and is charged.

[0115] In the third embodiment, it is conceivable that the degradation of the lithium-ion battery 1 will progress more than that of the lithium-ion battery 1 involved in the second embodiment, especially that the electrolyte 39 will dry out at the periphery 3z of the battery cell 3.

[0116] Reference Figure 9 The recycling system 400 of the third embodiment is similar to the recycling system 300 of the second embodiment in that it includes a pressing device 301, and the lithium-ion battery 1 is supplied to the recycling unit 10 in the form of a battery cell 3.

[0117] like Figure 10 As shown, in the third lithium deposition process S13, charging is performed by activating only the central pressing element 302A located at the center of the width direction B and / or height direction C of the battery cell 3 among the multiple sets of pressing elements 302, thereby charging only in the state of pressing the central portion 3a in the width direction B of the battery cell 3. Therefore, in the third lithium deposition process S13, the central portion 3a of the battery cell 3 in the plane perpendicular to the stacking direction A is charged with increased pressing force in the stacking direction A compared to the remaining portions 3b and 3c.

[0118] For example, when the pressing element pair 302 is arranged in a configuration of four that are approximately equally divided in the width direction B, only the two pressing element pairs 302 located on the inner side of the width direction B can be activated. Furthermore, when the pressing element pair 302 is arranged in a configuration of five that are approximately equally divided in the width direction B, only the three pressing element pairs 302 located on the inner side of the width direction B can be activated, or only the pressing element pair 302 located at the center of the width direction B can be activated. That is, in the third lithium deposition process S13, the portion including the central portion 3a of the battery cell 3 but excluding the peripheral portion 3z can be pressed.

[0119] As a result, in addition to the effect of pulse charging under cooling, the following effects are also achieved: In the two side portions 3b and 3c of the battery cell 3, the electrolyte easily escapes from the peripheral portion 3z to the outside, resulting in liquid drying. On the other hand, in the central portion 3a, since it is far from the peripheral portion 3z, the electrolyte 39 easily remains. Therefore, by increasing the pressing pressure at the central portion 3a where the electrolyte 39 easily remains, lithium can be efficiently deposited on the negative electrode material 35 corresponding to the central portion 3a.

[0120] Here, in the third lithium deposition process S13, as long as the lithium-ion battery 1 is in a pressed state, it can be charged. The pressing process of the pressing device 301 on the lithium-ion battery 1 and the charging process of the charging device 12 on the lithium-ion battery 1 can start simultaneously, or one of them can start first. That is, the charging process based on the charging device 12 can be performed after the pressing process based on the pressing device 301 is implemented, while maintaining the pressing state based on the pressing device 301.

[0121] [Fourth Implementation Method]

[0122] Figure 11 This is a flowchart that schematically illustrates the process of reusing the lithium-ion battery 1 according to the fourth embodiment. For example... Figure 11 As shown, in the fourth embodiment, a gas extrusion step S14 is performed before the lithium deposition step S2. In the gas extrusion step S14, based on the premise that gas is generated inside the lithium-ion battery 1, the gas is extruded to the peripheral portion 3z side of the lithium-ion battery 1 by pressing sequentially in the stacking direction A under specified pressing conditions.

[0123] When gas is generated inside the lithium-ion battery 1, the appearance of the lithium-ion battery 1 will expand, so the generation of gas can be confirmed by the appearance of the lithium-ion battery 1. In addition, since the generation of gas causes a change in the internal pressure of the lithium-ion battery 1, the generation of gas can also be confirmed by the change in the pressing force of the pressing device 301 described later.

[0124] Typically, when gas is generated within the lithium-ion battery 1, this gas hinders the movement of electrons between the positive electrode material 31 and the negative electrode material 35, making the charge-discharge reaction difficult to occur. This gas is a byproduct generated from the electrolyte 39 during the charge-discharge reactions of the lithium-ion battery 1 in both primary and secondary uses. The gas is, for example, methane and / or carbon dioxide.

[0125] Reference Figure 9 The recycling system 500 of the fourth embodiment also includes a pressing device 301, just like the recycling system 300 of the second embodiment, and the lithium-ion battery 1 is supplied to the recycling unit 10 in the form of a battery cell 3.

[0126] In the gas extrusion step S14, the gas generated within the battery cell 3 is extruded to the peripheral portion 3z by sequentially operating the pressing elements 302 of the multiple sets of pressing elements 302 from one side 3b to the other side 3c in the width direction B, or sequentially operating from the central portion 3a in the width direction B to both sides 3b and 3c in the width direction B. Therefore, when gas is generated in the battery cell 3, before the lithium deposition step S2, a gas extrusion step is included to extrude the gas toward the peripheral portion 3z of the negative electrode material 35 in an in-plane direction perpendicular to the stacking direction A.

[0127] For example, such as Figure 12A As shown, it is also possible to press the central portion 3a of the width direction B of the battery cell 3 first, as shown in the figure. Figure 12B As shown, the two sides 3b and 3c in the width direction B are further pressed. As a result, gas is squeezed from the central part 3a side of the battery cell 3 in the width direction B to the two sides 3b and 3c sides. In addition, in order to prevent the squeezed gas from flowing back to the central part 3a, etc. of the battery cell 3, each part 3a, 3b, and 3c of the battery cell 3 remains in a pressed state.

[0128] In addition, such as Figure 13A As shown, it is also possible to press one side 3b of the battery cell 3 in the width direction B, as... Figure 13B As shown, add a central portion 3a in the width direction, and then... Figure 13C As shown, the other side 3c in the width direction B is further pressed. As a result, gas is squeezed from the side 3b in the width direction B to the other side 3c. Furthermore, in order to prevent the squeezed gas from flowing back to the central part 3a, etc. of the battery cell 3, each part 3a, 3b, 3c of the battery cell 3 remains in a pressed state.

[0129] As a result, in addition to the effect of pulse charging under cooling, the following effects are also achieved: By expelling the gas towards the peripheral portion 3z, the electrolyte 39 is easily present around the negative electrode material 35. Consequently, even in battery cells 3 where gas has been generated, a charging reaction can be initiated at the negative electrode material 35. Therefore, even in battery cells 3 where gas has been generated, the charging reaction can be promoted through high-rate charging or charging under cooling, or through charging in a locally pressed state. As a result, lithium deposition occurs at sites where the charging reaction in the negative electrode material 35 is easily promoted.

[0130] In the second to fourth embodiments described above, the case where the lithium-ion battery 1 is supplied to the recycling process S1 as a single cell 3 and then subjected to the lithium deposition process is illustrated, but the method is not limited to this. The lithium-ion battery 1 may also be supplied to the recycling process S1 and / or the lithium deposition process as a battery pack or battery module 4. In this case, a pressing device 301 may be pre-installed inside the battery pack or battery module 4.

[0131] The lithium-ion battery 1 recycling system disclosed herein is not limited to the configuration described in the above embodiments, and various modifications can be made.

[0132] In the above embodiments, a laminated lithium-ion battery was used as an example, but the method is not limited to this. For example, a cylindrical or square shape can also be used, which is formed by winding a strip-shaped laminated electrode body, which is formed by stacking strip-shaped positive electrode material, strip-shaped separator, and strip-shaped negative electrode material in the stacking direction A, into a cylindrical or square shape. In the case of cylindrical and square shapes, the stacking direction is equivalent to the radial direction orthogonal to the winding direction.

[0133] Although described on a single-unit basis, it can also be implemented on a module basis or a battery pack basis. When implemented on a battery pack basis, pressing devices, cooling devices, etc., can be pre-installed within the battery pack.

[0134] [Postscript]

[0135] According to the lithium-ion battery 1 recycling system 100, 300, 400, 500 involved in this disclosure, the following methods are provided.

[0136] [Method 1]

[0137] A battery processing method for processing lithium-ion batteries containing positive electrode materials and negative electrode materials.

[0138] The process includes a lithium deposition step, in which lithium is deposited on the negative electrode material by pulse charging of the lithium-ion battery under cooling.

[0139] In the pulse charging, charging phases and charging pause phases are alternately performed, and the charging phases are performed at least multiple times.

[0140] During the charging phase, the lithium-ion battery is cooled.

[0141] [Method 2]

[0142] In the battery processing method described in Method 1

[0143] The lithium-ion battery with an output density of 4000 kW / L or higher is taken as the example.

[0144] [Method 3]

[0145] In the battery processing method described in method 1 or 2

[0146] The lithium-ion battery further includes an electrolyte and is configured such that the positive electrode material and the negative electrode material are stacked in the stacking direction.

[0147] The battery processing method further includes a gas extrusion step, wherein, when the lithium-ion battery generates gas, prior to the lithium deposition step, the gas is extruded from the center of the lithium-ion battery toward the periphery in an in-plane direction perpendicular to the stacking direction.

[0148] [Method 4]

[0149] In any one of the battery processing methods 1 to 3

[0150] The pulse charging also includes a discharge phase that discharges the lithium-ion battery.

[0151] [Method 5]

[0152] In any one of the battery processing methods 1 to 4

[0153] The lithium-ion battery further includes an electrolyte and is configured such that the positive electrode material and the negative electrode material are stacked in the stacking direction.

[0154] In the lithium deposition process, the pressure applied in the central portion of the plane perpendicular to the stacking direction is increased compared to the remaining portion.

[0155] [Method 6]

[0156] In any one of the battery processing methods 1 to 5

[0157] The battery processing method further includes a lithium extraction step of extracting lithium from the negative electrode material.

[0158] The lithium extraction process includes leaching and filtering the negative electrode material.

[0159] [Method 7]

[0160] In the battery processing method described in Method 6

[0161] The battery processing method further includes a lithium recovery process performed after the lithium extraction process.

[0162] The lithium recovery process includes immersing the extracted lithium in carbonated water and then filtering it to recover it as lithium carbonate.

[0163] [Method 8]

[0164] A battery processing system for processing lithium-ion batteries containing positive electrode materials and negative electrode materials, comprising:

[0165] A charging device that performs pulse charging on the lithium-ion battery, the pulse charging having alternating charging phases and charging pause phases, and having at least multiple charging phases; and

[0166] A cooling device that cools the lithium-ion battery during the charging phase.

[0167] [Method 9]

[0168] In the battery processing method described in Method 1

[0169] The lithium-ion battery is configured such that the positive electrode material and the negative electrode material are stacked in the stacking direction.

[0170] The cooling is performed by a cooling device arranged in pairs on both sides of the stacking direction of the lithium-ion battery.

[0171] [Method 10]

[0172] In the battery processing method described in Method 9

[0173] In the gas extrusion process, the gas is extruded by a pressing device that presses the lithium-ion battery along the stacking direction with a specified pressing force.

[0174] [Method 11]

[0175] In the battery processing method described in method 10

[0176] In the lithium deposition process, the lithium-ion battery is pressed by a pressing device having multiple sets of pressing member pairs divided in the width direction of the lithium-ion battery, with each set of pressing member pairs arranged in pairs on both sides of the stacking direction of the lithium-ion battery.

[0177] In the lithium deposition process, only a portion of the multiple sets of pressing elements are activated.

Claims

1. A battery processing method for processing lithium-ion batteries containing positive electrode materials and negative electrode materials, characterized in that, The process includes a lithium deposition step, in which the lithium-ion battery is pulse-charged under cooling to deposit lithium on the negative electrode material. During the pulse charging, charging phases and charging pause phases are alternately performed, and the charging phases are performed at least multiple times. During the charging phases, the lithium-ion battery is cooled.

2. The battery processing method according to claim 1, characterized in that, The lithium-ion battery with an output density of 4000 kW / L or higher is taken as the example.

3. The battery processing method according to claim 1, characterized in that, The lithium-ion battery further includes an electrolyte and is configured such that the positive electrode material and the negative electrode material are stacked in the stacking direction. The battery processing method further includes a gas extrusion step, wherein, when the lithium-ion battery generates gas, prior to the lithium deposition step, the gas is extruded from the center of the lithium-ion battery toward the periphery in an in-plane direction perpendicular to the stacking direction.

4. The battery processing method according to claim 1, characterized in that, The pulse charging also includes a discharge phase that discharges the lithium-ion battery.

5. The battery processing method according to claim 1, characterized in that, The lithium-ion battery further includes an electrolyte and is configured such that the positive electrode material and the negative electrode material are stacked in the stacking direction. In the lithium deposition process, the pressing pressure in the stacking direction is increased in the central portion of the plane perpendicular to the stacking direction compared to the remaining portion.

6. The battery processing method according to claim 1, characterized in that, The battery processing method further includes a lithium extraction step of extracting lithium from the negative electrode material. The lithium extraction process includes leaching and filtering the negative electrode material.

7. The battery processing method according to claim 6, characterized in that, The battery processing method further includes a lithium recovery process performed after the lithium extraction process. The lithium recovery process includes immersing the extracted lithium in carbonated water and then filtering it to recover it as lithium carbonate.

8. The battery processing method according to claim 1, characterized in that, The lithium-ion battery is configured such that the positive electrode material and the negative electrode material are stacked in the stacking direction. The cooling is performed by a cooling device arranged in pairs on both sides of the stacking direction of the lithium-ion battery.

9. The battery processing method according to claim 3, characterized in that, In the gas extrusion process, the gas is extruded by a pressing device that presses the lithium-ion battery along the stacking direction with a specified pressing force.

10. The battery processing method according to claim 5, characterized in that, In the lithium deposition process, the lithium-ion battery is pressed by a pressing device having multiple sets of pressing member pairs divided in the width direction of the lithium-ion battery, with each set of pressing member pairs arranged in pairs on both sides of the stacking direction of the lithium-ion battery. In the lithium deposition process, only a portion of the pressing elements in the multiple sets of pressing elements are activated.

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