How to disassemble a chemical battery

Abstract

This invention provides a method for recovering valuable metals from chemical batteries, achieving a recovery rate of 95% or more for cobalt and nickel, and 80% or more for lithium, while also providing a method for decomposing chemical batteries that does not require roasting, suppresses the generation of carbon dioxide, and does not reduce the processing efficiency of the chemical battery decomposition. [Solution] A method for disassembling a chemical battery includes a cutting step in which the chemical battery is cut with a cutting blade; a chip removal step in which the cutting blade is brought into contact with a chip removal device and chips are removed from the cutting blade; an ultrasonic application step in which ultrasonic waves are applied to the cutting blade through a liquid; and a collection step in which the liquid containing the chips is collected.

Description

Technical Field

[0001] The present invention relates to a method for disassembling chemical batteries. Background Art

[0002] With the popularization of lithium-ion batteries, competition for securing valuable metals used as raw materials for lithium-ion batteries has intensified. Not only is there concern about the depletion of valuable metal resources, but in resource-rich countries, natural destruction due to excessive mining development and forced labor are also concerns. In countries with scarce natural resources, there are concerns over securing stable volumes and fluctuations in procurement prices. In order to reduce the burden on the global environment caused by excessive mining development, waste disposal, and other activities, methods for recovering valuable metals such as cobalt, nickel, manganese, and lithium from spent lithium-ion batteries and reusing them as materials for new lithium-ion batteries are being studied. In recent years, the perspective of recycling rate of lithium-ion batteries has also become important, and not only valuable metals such as cobalt, nickel, and lithium contained in positive electrode materials, but also carbon and copper contained in negative electrode materials, and even the separators themselves are targeted for recovery. In Europe, a battery regulation that requires a recovery rate of 95% or more for cobalt and nickel in lithium-ion batteries, and 80% or more for lithium by 2031 entered into force on August 17, 2023.

[0003] Furthermore, the environmental impact of lithium-ion battery recycling has also attracted attention. Moving toward a decarbonized society, the recycling industry is required to avoid greenhouse gas emissions.

[0004] Furthermore, a new method, in which the casing of a lithium-ion battery is cut, and the positive electrode foil, separator, and negative electrode foil are taken out from the casing, so that aluminum derived from the casing is separated before the valuable metals are recovered, has also attracted attention.

[0005] Patent Document 1 discloses a system for discharging used lithium-ion batteries or lithium-ion batteries discarded as defective products during the manufacturing process, then subjecting them to heat treatment (roasting), crushing them with a crusher such as a hammer mill or jaw crusher, removing the housing, current collector, etc. that make up the waste lithium-ion batteries by sieving (classification) to obtain active material powder, and recovering lithium by processing the active material powder. [Prior art documents] [Patent Documents]

[0006] [Patent Document 1] Patent No. 7060899 [Overview of the project] [Problems that the invention aims to solve]

[0007] The lithium recovery system from waste lithium-ion batteries disclosed in Patent Document 1 has a problem in that, as a result of valuable metals remaining on the sieve during sieving, more than 5% of cobalt and nickel are lost, and the recycling rate stipulated in the aforementioned battery regulations cannot be achieved. Furthermore, carbon powder and organic matter are roasted in conventional waste lithium-ion battery recycling methods in order to obtain active material powder, resulting in the generation of carbon dioxide. Therefore, there has been a need for a method of recovering valuable metals from chemical batteries that can recover cobalt and nickel at a rate of 95% or more, and lithium at a rate of 80% or more. There has also been a need for a waste lithium-ion battery recycling method that can obtain active material powder without roasting.

[0008] Furthermore, in new chemical battery disassembly methods that separate the casing, cutting debris adheres to and welds to the blade used to cut the casing, resulting in a decrease in the blade's cutting ability. This increases the cycle time involved in the chemical battery disassembly process, significantly reducing processing efficiency. Moreover, valuable metals in the chemical battery remain on the blade as cutting debris, resulting in a significant decrease in the recovery efficiency of valuable metals. Therefore, there has been a strong demand for a chemical battery disassembly method that does not reduce the efficiency of cutting the casing.

[0009] The problem that this invention aims to solve is to provide a method for decomposing a chemical battery that contributes to a method for recovering valuable metals from a chemical battery, such as recovering cobalt and nickel at a recovery rate of 95% or more, and lithium at a recovery rate of 80% or more. Furthermore, another problem that this invention aims to solve is to provide a method for decomposing a chemical battery that does not require roasting and suppresses the generation of carbon dioxide. Furthermore, another problem that this invention aims to solve is to provide a method for decomposing a chemical battery that does not reduce the processing efficiency involved in the decomposition of the chemical battery. [Means for solving the problem]

[0010] In view of the above problems, the inventors have conducted extensive research and found that a method for disassembling a chemical battery, comprising a cutting step in which the chemical battery is cut with a cutting blade, a cutting debris removal step in which the cutting blade is brought into contact with a cutting debris removal device and cutting debris is removed from the cutting blade, an ultrasonic application step in which ultrasonic waves are applied to the cutting blade through a liquid, and a collection step in which the liquid containing the cutting debris is collected, contributes to a method for disassembling a chemical battery that achieves the recycling rate stipulated in the aforementioned battery regulations, suppresses the generation of carbon dioxide without requiring roasting, and does not reduce the processing efficiency related to the disassembly of the chemical battery. The present invention was completed based on these findings.

[0011] The present invention relates to a method for disassembling a chemical battery, comprising: a cutting step in which the chemical battery is cut with a cutting blade; a chip removal step in which the cutting blade is brought into contact with a chip removal device and chips are removed from the cutting blade; an ultrasonic application step in which ultrasonic waves are applied to the cutting blade through a liquid; and a collection step in which the liquid containing the chips is collected. Preferably, the method further includes a recovery step in which the cutting chips collected in the collection step are recovered by specific gravity separation according to their raw material. Preferably, the method further includes a liquid removal step in which the liquid adhering to the cutting blade after the ultrasonic application step is removed. The aforementioned chemical battery is preferably a secondary battery. The secondary battery is preferably a lithium-ion battery. The method for disassembling the chemical battery preferably further includes a pretreatment step in which the lithium-ion battery is discharged and the electrolyte in the lithium-ion battery is removed; an electrode separation step in which the electrode body is pushed out from inside the lithium-ion battery and removed; and a peeling step in which the positive electrode, separator, and negative electrode constituting the electrode body are peeled off. The present invention relates to a chemical battery disassembly apparatus, comprising: a cutting unit for cutting the chemical battery with a cutting blade; a cutting debris removal unit for bringing the cutting blade into contact with a cutting debris removal device and removing cutting debris from the cutting blade; an ultrasonic application unit for applying ultrasonic waves to the cutting blade via a liquid; and a collection unit for collecting the liquid containing the cutting debris. [Effects of the Invention]

[0012] The present invention provides a method for decomposing a chemical battery that contributes to the recovery of valuable metals from a chemical battery, achieving a recovery rate of 95% or more for cobalt and nickel, and 80% or more for lithium. Furthermore, the present invention provides a method for decomposing a chemical battery that does not require roasting and suppresses the generation of carbon dioxide. Moreover, the present invention provides a method for decomposing a chemical battery that does not reduce the cutting efficiency of the casing. [Brief explanation of the drawing]

[0013] [Figure 1] An explanatory diagram showing the configuration of one embodiment of the method for decomposing a chemical battery according to the present invention. [Figure 2] A cross-sectional view of chemical battery 1, which is one embodiment of a chemical battery. [Figure 3] An explanatory diagram showing a first embodiment of the cutting step. [Figure 4] An explanatory diagram showing one embodiment of the ultrasonic application step. [Figure 5] An explanatory diagram showing one embodiment of the recovery step. Mode for Carrying Out the Invention

[0014] The present invention will be described in further detail below. Furthermore, in the description of the drawings, the same elements are denoted by the same reference numerals, and repeated descriptions are omitted. In addition, the dimensional ratios in the drawings are exaggerated for convenience of description, and may differ from the actual ratios.

[0015] The method for disassembling a chemical battery of the present invention may include a discharging step (STEP A in FIG. 1) of discharging the chemical battery to reduce residual charge. Said chemical battery generates electricity through an internal chemical reaction and extracts the electrical energy, and is classified into three types: primary batteries, secondary batteries, and fuel cells. Said preferable chemical battery is a secondary battery, and said more preferable chemical battery is a lithium-ion battery. Said chemical battery may include at least one selected from the group consisting of spent chemical batteries and chemical batteries discarded as defective products in the manufacturing step. It is desirable that said residual charge is as small as possible.

[0016] <Cutting Step> The method for disassembling a chemical battery of the present invention includes a cutting step in which the casing and the current collector are cut. FIG. 2 is a cross-sectional view of chemical battery 1, which is one embodiment of a chemical battery. The chemical battery 1 includes a casing 2, an electrode assembly 3, electrode terminal plates 4 (a positive electrode 4a and a negative electrode 4b), and current collectors 5 (a positive electrode-side current collector 5a and a negative electrode-side current collector 5b), wherein the electrode assembly 3 and the electrode terminal plates 4 are covered by the casing 2. Furthermore, the electrode assembly 3 and the electrode terminal plates 4 are electrically connected via the current collectors 5. The method for disassembling a chemical battery of the present invention includes a cutting step in which the casing and the current collector are cut by a cutting blade provided in a cutting unit.

[0017] FIG. 3 is an explanatory diagram showing one embodiment of the cutting step. The casing 2 is box-shaped, and the casing 2 and the current collector 5 are cut in a direction perpendicular to the surface to which the electrode terminal plate 4 is attached. The cutting position is at least one selected from the group consisting of the positive electrode 4a side (the broken line on the left side of FIG. 3) and the negative electrode 4b side (the broken line on the right side of FIG. 3). The cutting blade may be, for example, a bandsaw whose blade rotates in one direction.

[0018] <Cutting chip removing step> The method for disassembling a chemical battery according to the present invention may include a cutting chip removing step in which the cutting blade is brought into contact with a cutting chip removing implement (8 in FIG. 4) to remove cutting chips from the cutting blade. After the cutting step, the cutting blade to which the cutting chips have adhered and been welded is brought into contact with the cutting chip removing implement provided in a cutting chip removing unit, whereby the cutting chips are removed. The cutting chip removing implement is, for example, a wheel brush.

[0019] The cutting chips may include, for example, at least one selected from the group consisting of aluminum chips, copper chips, and resin chips derived from the casing and the current collector, and are preferably at least one selected from the group consisting of aluminum chips, copper chips, and resin chips.

[0020] <Ultrasonic wave applying step> The present invention provides a method for decomposing a chemical battery, which includes an ultrasonic application step in which ultrasonic waves are applied to the cutting blade via a liquid. In the cutting step, the temperature of the cutting blade rises due to frictional heat between the cutting blade and the chemical battery, and cutting debris is welded to the cutting blade. In the ultrasonic application step, the temperature of the cutting blade decreases as it comes into contact with the liquid. Furthermore, by applying ultrasonic waves to the cutting blade via the liquid using an ultrasonic application unit, the cutting debris adhering to and welded to the cutting blade is removed. In existing methods, when cutting a chemical battery with a cutting blade, the cutting ability is reduced because cutting debris originating from the chemical battery adheres to and welds to the cutting blade. By providing the removal step and the ultrasonic application step, it is possible to prevent the cutting debris from remaining on the cutting blade and suppress the decrease in the cutting ability of the chemical battery. This suppresses the decrease in processing efficiency due to an increase in the cycle time related to the decomposition process of the chemical battery. Furthermore, it is possible to prevent valuable metals in the chemical battery from remaining on the cutting blade as cutting debris and suppress the decrease in the recovery efficiency of valuable metals. The liquid comprises at least one selected from the group consisting of water, oil, and a mixture of water and oil, and is preferably a mixture of water and oil. The oil is preferably a cutting oil.

[0021] Figure 4 is an explanatory diagram showing one embodiment of the ultrasonic application step. The cutting blade 7, to which cutting debris is attached and welded, comes into contact with the liquid 9a, and ultrasonic waves are applied through the liquid 9a. The ultrasonic waves are generated by an ultrasonic transducer 9b that comes into contact with the liquid tank 9 containing the liquid 9a.

[0022] <Collection Steps> The present invention provides a method for disassembling a chemical battery, which includes a collection step in which the liquid containing the cutting debris is collected. The cutting debris removed from the cutting blade in the cutting debris removal step falls into the liquid and is collected by a collection unit. The cutting debris collected by the collection unit may include, in addition to the cutting debris removed from the cutting blade in the cutting debris removal step, cutting debris detached from the cutting blade in the ultrasonic application step, and cutting debris that falls from the cutting site when the casing and current collector are cut in the cutting step. Since valuable metals contained in the chemical battery are collected in the collection step, the method for disassembling a chemical battery of the present invention can achieve the recovery rate specified in the battery regulations.

[0023] <Recovery Step> The method for disassembling a chemical battery according to the present invention may include a recovery step in which the cutting debris collected in the collection step is recovered separately by specific gravity separation. The raw materials are, for example, aluminum, copper, resin, etc. The raw materials recovered in the recovery step may be reused as resources. Since valuable metals contained in the chemical battery are recovered in the recovery step, the method for disassembling a chemical battery according to the present invention can achieve the recovery rate specified in the battery regulations.

[0024] Figure 5 is an explanatory diagram showing one embodiment of the recovery step. The liquid containing the cutting debris collected in the collection step is separated into the cutting debris and the liquid by a recovery device 10 connected to the liquid tank 9, for example, and the cutting debris is recovered by specific gravity separation according to its raw material. The recovery device 10 is, for example, a classifier filter. The liquid may be discharged outside the system or may be circulated within the system and reused in the ultrasonic application step.

[0025] <Liquid Removal Step> The method for disassembling a chemical battery according to the present invention may include a liquid removal step in which the liquid adhering to the cutting blade after the ultrasonic application step is removed. In the liquid removal step, the liquid is removed by applying a liquid removal device (11 in Figure 4) to the cutting blade to which the liquid is adhering. The liquid removal device is, for example, a liquid adsorption roll or an air blower.

[0026] <Electrode separation step> The method for disassembling a chemical battery according to the present invention may include an electrode separation step (STEP 1 in Figure 1) in which the casing of the chemical battery is cut and the electrode body is removed from inside the casing. The chemical battery is a battery that generates electricity through an internal chemical reaction and extracts that electrical energy, and is classified into three types: primary batteries, secondary batteries, and fuel cells. The preferred chemical battery is a secondary battery, and the more preferred chemical battery is a lithium-ion battery. The chemical battery may include at least one selected from the group consisting of used chemical batteries and chemical batteries discarded as defective products in the manufacturing step.

[0027] The electrode body constituting the chemical battery is covered by the casing. In the electrode body separation step, the casing is cut and the electrode body is removed from inside the casing. The electrode body separation step allows for the separation of aluminum derived from the casing, which is unnecessary as active material powder. In existing methods, aluminum was crushed together with the electrode body, sieved, and separated. In that case, the valuable metal remained on the sieve, reducing the recovery rate of the valuable metal. This inconvenience is resolved in the electrode body separation step, thus suppressing the reduction in the recovery rate of the valuable metal. Furthermore, since the separated casing is not mixed with other materials, it can be recycled as an aluminum resource as is. After the casing is cut in the electrode body separation step, the electrolyte inside the casing is recovered as a resource.

[0028] <First peeling step> The electrode body comprises a positive electrode foil, a separator, and a negative electrode foil. The positive electrode foil, separator, and negative electrode foil constituting the electrode body are all in the form of film. The positive electrode foil is placed on one side of the separator, and the negative electrode foil is placed on the other side of the separator. These are wound, folded, or otherwise arranged to form a single unit. The ends of the separator are fixed by fastening means such as tape, adhesive, or crimping. In Figures 2-4, the ends of the separator are fixed with tape 6.

[0029] If the positive electrode foil and the negative electrode foil can be separated, the method for disassembling a chemical battery of the present invention may include a first peeling step (STEP 2 in Figure 1) in which the fixed portion of the electrode body obtained in the electrode body separation step is peeled off. In the first peeling step, the fixed portion is peeled off by a peeling unit. The peeling unit is not limited to a specific peeling unit. Examples of the peeling unit include a brush, a cutting unit, a roller, an application of tape remover, a scraper, etc. Conventionally, the peeling off of the fixed portion had not been considered, but in the method for disassembling a chemical battery of the present invention, the automation of the peeling off of the fixed portion has been considered. Note that the first peeling step is not performed manually but is performed by the peeling unit. The ends of the separator on which the positive electrode foil and the ends of the separator on which the negative electrode foil are placed, peeled off in the first peeling step, become the starting points for winding in the second peeling step, which will be described later.

[0030] <Second peeling step> The method for disassembling a chemical battery of the present invention may include a second peeling step (STEP 3 in Figure 1) in which the positive electrode foil, separator, and negative electrode foil constituting the electrode body are each peeled off. After the adhesive portion is peeled off, the positive electrode foil, separator, and negative electrode foil, which were wound together and integrated, are each peeled off. The peeled positive electrode foil, separator, and negative electrode foil may each be wound together.

[0031] The method for disassembling a chemical battery according to the present invention may include a grinding step (STEP 4a in Figure 1) for grinding the positive electrode foil obtained in the second peeling step. The positive electrode foil obtained in the grinding step may be subjected to a step in which the valuable metals are recovered (STEP 4b in Figure 1). Furthermore, the positive electrode foil obtained in the second peeling step may be subjected to a step in which the valuable metals are recovered (STEP 4b in Figure 1) without being ground, and may be reused as the positive electrode foil of a chemical battery as is (STEP 4c in Figure 1). The negative electrode foil obtained in the second peeling step may be subjected to a step in which the valuable metals are recovered (STEP 4b in Figure 1) without being ground.

[0032] If the positive and negative electrode foils cannot be separated, they may be subjected to a step in which they are roasted, the remaining components from which the carbon has been removed are dissolved in an acid solution, and the valuable metals are recovered.

[0033] In Figures 2 and 3, the casing 2 is box-shaped, but the casing 2 may have a shape other than a box, such as a cylinder.

[0034] The present invention's method for disassembling a chemical battery does not include the crushing and sieving steps that were included in conventional methods for recovering valuable metals from waste lithium-ion batteries, which involve crushing the entire chemical battery and sieving the resulting pulverized material. Therefore, the present invention's method for disassembling a chemical battery does not result in the loss of valuable metals that would have been lost in the crushing and sieving steps. As a result, the present invention's method for disassembling a chemical battery contributes to a method for recovering valuable metals from chemical batteries that achieves the recovery rate stipulated in the battery regulations. Furthermore, since the present invention's method for disassembling a chemical battery yields positive electrode foil powder without going through a roasting step, it can suppress the generation of carbon dioxide and contribute to reducing environmental impact. Moreover, since the present invention's method for disassembling a chemical battery removes and peels off cutting debris that has adhered to and welded to the cutting blade used to cut the casing, it can suppress a decrease in processing efficiency related to the disassembly of the chemical battery and contribute to the efficient recovery of valuable metals. [Explanation of Symbols]

[0035] 1...Chemical battery, 2...Casing, 3...Electrode body, 4a...Positive terminal plate, 4b...Negative terminal plate, 5a... Positive electrode current collector, 5b... Negative electrode current collector, 6... Tape, 7...Cutting blade, 8...Cutting chip removal device, 9...Liquid tank, 9a...Liquid, 9b...Ultrasonic transducer, 10...Recovery device, 10a...Aluminum scrap, 10b...Copper scrap, 10c...Resin scrap, 11...Liquid removal device.

Claims

1. A method for disassembling a chemical battery, In the cutting step, the chemical cell is cut with a cutting blade. A cutting blade is brought into contact with a cutting chip removal device, and cutting chips are removed from the cutting blade in a cutting chip removal step. The cutting blade is subjected to an ultrasonic application step in which ultrasonic waves are applied via a liquid, and A method for disassembling a chemical battery, comprising a collection step in which the liquid containing the cutting debris is collected.

2. A method for disassembling a chemical battery as described in claim 1, A method for disassembling a chemical battery, further comprising a recovery step in which the cutting debris collected in the collection step is recovered separately by specific gravity separation.

3. A method for disassembling a chemical battery as described in claim 1, A method for disassembling a chemical battery, further comprising a liquid removal step in which the liquid adhering to the cutting blade after the ultrasonic application step is removed.

4. A method for disassembling a chemical battery according to any one of claims 1 to 3, wherein the chemical battery is a secondary battery.

5. A method for disassembling a chemical battery according to claim 4, wherein the secondary battery is a lithium-ion battery.

6. A method for disassembling a chemical battery as described in claim 5, A pre-treatment step in which the lithium-ion battery is discharged, and then the electrolyte in the lithium-ion battery is removed. An electrode separation step in which the electrode body is pushed out and removed from inside the lithium-ion battery, and A method for disassembling a chemical battery, further comprising a peeling step in which the positive electrode, separator, and negative electrode constituting the electrode body are peeled off.

7. A device for disassembling chemical batteries, A cutting unit that cuts the chemical battery with a cutting blade. A cutting chip removal unit that brings the cutting blade into contact with a cutting chip removal device and removes cutting chips from the cutting blade. An ultrasonic application unit that applies ultrasonic waves to the cutting blade via a liquid, and A chemical battery disassembly apparatus comprising a collection unit for collecting the liquid containing the cutting debris.

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