Recovery method for positive electrode active material and / or current collector, positive electrode active material material, and current collector material
Laser irradiation at controlled temperature and power density facilitates efficient separation of current collectors and positive electrode active materials in lithium-ion batteries, achieving high-purity recovery and recycling of valuable metals.
Patent Information
- Authority / Receiving Office
- WO · WO
- Patent Type
- Applications
- Current Assignee / Owner
- MATSUDA SANGYO
- Filing Date
- 2024-11-13
- Publication Date
- 2026-05-21
AI Technical Summary
Existing methods for separating current collectors and positive electrode active materials in lithium-ion batteries are inefficient and result in materials with high impurity content, making recycling difficult and costly.
A method involving laser irradiation of the positive electrode material at controlled temperature and power density to separate the current collector and positive electrode active material, followed by sieving, which allows for efficient recovery of high-purity positive electrode active material.
Effectively separates current collectors and positive electrode active materials with low impurity content, enabling efficient recycling and reuse of valuable metals.
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Abstract
Description
Method for recovering positive electrode active material and / or current collector, positive electrode active material, current collector material
[0001] This disclosure relates to a method for recovering positive electrode active material and / or current collector, positive electrode active material material, and current collector material.
[0002] Lithium-ion batteries have been used as batteries for small mobile devices such as mobile phones, laptop computers, and video cameras. In recent years, as electric vehicles have become more widespread as part of decarbonization efforts, large lithium-ion batteries for automotive use are being produced in large quantities. Nowadays, research is actively being conducted on the development of new materials for the negative and positive electrodes, as well as on solid electrolytes, in order to improve safety and volumetric energy density.
[0003] Generally, lithium-ion batteries consist of a positive electrode material, a negative electrode material, a separator, and an electrolyte. The positive electrode uses aluminum foil (current collector) coated with positive electrode active materials such as lithium cobalt oxide, lithium nickel oxide, or lithium manganese oxide along with an adhesive (binder). The negative electrode uses copper foil (current collector) coated with negative electrode active materials such as carbon or graphite along with an adhesive. These components are housed in a metal casing.
[0004] Lithium-ion batteries contain valuable metals such as lithium, cobalt, nickel, and manganese. Therefore, after repeated charging and discharging and use, the positive electrode active material and other valuable metals are separated and recovered. Regarding recovery methods, for example, Patent Document 1 describes a method in which the lithium-ion battery positive electrode material is crushed into granules while being wrinkled, separating it into a current collector and a positive electrode active material, and the current collector is recovered on the upper side of the sieve and the positive electrode active material on the lower side of the sieve.
[0005] Patent Document 2 discloses a technique for separating and recovering lightweight aluminum-based materials and heavy copper-based materials by coarsely crushing the positive electrode material and negative electrode material, removing resins and magnetic deposits from the coarse crushed mixture, then performing secondary crushing, sieving the secondary crushed material, and separating it by specific gravity. Patent Document 3 describes heating the lithium-ion secondary battery to 600°C to 1200°C before crushing. Patent Document 4 describes applying a high-voltage pulse to the positive electrode of the lithium-ion battery. Patent Document 5 describes separating the current collector by performing ultrasonic treatment.
[0006] Japanese Patent No. 5667232, Japanese Patent No. 3634927, Japanese Patent No. 6984055, Japanese Unexamined Patent Publication No. 2023-166763, Japanese Unexamined Patent Publication No. 2022-106024
[0007] This disclosure aims to provide a technology that can efficiently separate the current collector and positive electrode active material contained in lithium-ion batteries. Furthermore, this disclosure aims to provide a positive electrode active material with low impurities that can be reused as a positive electrode active material.
[0008] The gist of this disclosure is as follows: [1] A method for recovering positive electrode active material and / or a current collector, comprising the steps of: irradiating a positive electrode material contained in a lithium-ion battery with a laser; separating the current collector and the positive electrode active material, or sieving them apart during or after separation, recovering the current collector on the sieve, and recovering the positive electrode active material below the sieve. [2] The method for recovering positive electrode active material and / or a current collector according to [1], characterized in that the laser is irradiated at an intensity such that the temperature of the positive electrode material is 300°C or higher and 660°C or lower. [3] The method for recovering positive electrode active material and / or a current collector according to [2], characterized in that the laser irradiation time is greater than 0 seconds and 200 seconds or less. [4] The average power density of the laser is 2 W / cm². ２ Above, 13W / cm ２ A method for recovering a positive electrode active material and / or current collector according to any one of [1] to [3] above, characterized in that: [5] The integrated illuminance of the laser is set to 0 J / cm ２ Super 1000J / cm ２A method for recovering positive electrode active material and / or current collector according to any one of [1] to [4] above, characterized in that it includes a step of crushing the positive electrode material of the lithium-ion battery before the step of irradiating with a laser. [7] A positive electrode active material characterized by being recovered using the method according to any one of [1] to [6] above. [8] A positive electrode active material according to [7] above, characterized by containing one or more of nickel, cobalt, manganese, and lithium, with nickel being 0 wt% to 50 wt%, cobalt being 0 wt% to 50 wt%, manganese being 0 wt% to 30 wt%, and lithium being 0 wt% to 10 wt%. [9] A positive electrode active material according to [8] above, characterized in that the aluminum content is 1 wt% or less.
[10] A current collector material characterized by being recovered using the recovery method according to any one of [1] to [6] above.
[11] The current collector material according to
[10] above, characterized in that the aluminum content is 70 wt% or more.
[0009] According to this disclosure, it is possible to effectively separate the current collector and the positive electrode active material contained in a lithium-ion battery. Furthermore, it is possible to provide a positive electrode active material with few impurities that can be reused as a positive electrode active material.
[0010] (Regarding raw materials) Generally, lithium-ion batteries consist of a positive electrode material, a negative electrode material, a separator, an electrolyte, etc. Embodiments of this disclosure use the positive electrode material contained in lithium-ion batteries as the raw material. The positive electrode material is made by bonding a positive electrode active material (lithium cobalt oxide, lithium nickel oxide, lithium manganese oxide, etc.) to a current collector (aluminum foil). Since the main purpose of this disclosure is recycling, the positive electrode material contained in used lithium-ion batteries can be used as the recovered raw material, but materials obtained from unused lithium-ion batteries or scraps generated from the battery manufacturing process may also be used as the recovered raw material.
[0011] Lithium-ion batteries include those for automotive and stationary use. The dimensions of the cathode material used as raw material vary; for automotive batteries, a width of about 20 cm is common, but for dry cell type batteries, a width of about 3 cm is also possible, and there are also those with a width of about 1 m. The length ranges from about 1 m to several hundred meters, and there are no particular limitations on the dimensions of the cathode material used as raw material. Furthermore, there are wound and laminated types of cathode / negative electrode structures, and cathode materials of various shapes and dimensions are distributed in a mixed state packed in flexible containers (bags). In this embodiment, the shape of the cathode material used as raw material is not particularly limited and may be in the shape of a strip, laminate, or various other shapes.
[0012] (Crushing process: Optional) In order to effectively perform the laser irradiation in the next process, it is preferable to crush the cathode material to the desired size. However, depending on the dimensions and shape of the raw material, crushing may not be necessary, and the crushing process is optional. There are no particular restrictions on the crushing method; for example, shear crushing using a cutter mill or shredder, or impact crushing using a hammer mill can be used. It is preferable to adjust the crushing method and conditions, taking into consideration the shape of the raw material, to produce a size suitable for laser irradiation. There are no particular restrictions on the method of feeding the raw material into the crusher, but for example, a vibratory feeder with a hopper can be used.
[0013] (Laser Irradiation Process) In positive electrode materials, the positive electrode active material is coated onto a current collector such as aluminum using an adhesive (such as fluororesin), making it extremely difficult to separate the current collector from the positive electrode active material. For this reason, methods such as heat treatment to decompose the adhesive are used, as described in Patent Document 3, but heat treatment has the problem of high energy costs. In addition, methods such as electrical pulse treatment and ultrasonic treatment, as described in Patent Documents 4 and 5, have been considered, but the recovered positive electrode materials differ in thickness and adhesive strength, and they are sometimes packed in overlapping layers in flexible containers, making it difficult to process them all at once. Furthermore, ultrasound causes significant damage to the aluminum foil (current collector). The embodiment of this disclosure irradiates the positive electrode material with a laser to facilitate the peeling of the positive electrode active material from the current collector. In particular, positive electrode active material has a high absorption rate of infrared light and is opaque, making it compatible with laser light. There are no particular restrictions on the laser light, but for example, one with a wavelength of 960 to 985 nm can be used.
[0014] In this embodiment, it is preferable to use a heating laser that can irradiate a wide area, rather than a so-called focused laser. Specifically, the laser is irradiated at an intensity that raises the temperature of the positive electrode material to 300°C or more and 660°C or less. If the temperature is below 300°C, the adhesive will not decompose sufficiently, and the positive electrode active material may not peel off from the current collector. On the other hand, if the temperature exceeds 660°C, the aluminum foil, which is the current collector, may melt, so the temperature should be between 300°C and 660°C. Preferably, it is between 450°C and 550°C. As long as the material can be heated to the above temperature, there are no particular restrictions on the irradiation time, but for example, it can be more than 0 seconds and 200 seconds or less. Irradiating the laser for more than 200 seconds will be costly, so it is not preferable to continue irradiation beyond that. Also, once the above temperature is reached, it may be 1 second or less. The peelability is best when the irradiation time is around 40 to 100 seconds.
[0015] Once the aforementioned temperature is reached, there are no particular restrictions on the power of the irradiated laser, but for example, an average power density of 2 W / cm² is recommended. ２ Above, 13W / cm ２ The following is possible: The positive electrode material is 400 cm².２ Then, it can be set to about 1 to 5 kW. 5 W / cm ２ Then, it reaches 500 °C in about 3 seconds. Without heat dissipation to the base, it will heat up faster, so it may reach about 500 °C even within 1 second. Also, the integrated irradiation intensity can be, for example, 0 J / cm ２ over 1000 J / cm ２ or less. Preferably 15 J / cm ２ or more, and more preferably 200 J / cm ２ or more. Also, preferably 500 J / cm ２ or less. The method of laser irradiation is not particularly limited. For example, a positive electrode material moving on a conveyor can be irradiated with a laser.
[0016] (Peeling process) After laser irradiation, the positive electrode material is separated into a current collector and a positive electrode active material. As the peeling method, impact, grinding, brushing, kneading, high-pressure water or gas spraying, etc. can be used. For example, a ball mill, a hammer mill, a disk mill, etc. can be used, and a vibrator with tapping balls can also be used. Since the laser energy is absorbed inside the positive electrode material as an electromagnetic wave, the heating efficiency is high, and in the subsequent peeling process, the current collector and the positive electrode active material can be peeled off extremely easily and simply.
[0017] (Sieving process) Sieving is performed after peeling or simultaneously with peeling. The material on the sieve is aluminum as the current collector, and the material under the sieve is recovered as the positive electrode active material. The recovered positive electrode active material may be purified into a valuable metal by another refining process, or may be reused as a positive electrode active material for a lithium-ion battery. Also, the recovered aluminum has a high grade of 70 wt% or more and can be further purified or reused.
[0018] As the positive electrode active material, a ternary oxide material of nickel, cobalt, and manganese can be used. Alternatively, materials other than ternary systems, such as cobalt-based (lithium cobalt oxide), nickel-based (lithium nickel oxide), manganese-based (lithium manganese oxide), NCA-based (nickel, cobalt, aluminum), and iron phosphate-based (lithium, iron, phosphorus), may also be used. The recycled positive electrode active material may contain one or more of nickel, cobalt, manganese, and lithium, and may contain 0 wt% to 50 wt% nickel, 0 wt% to 55 wt% cobalt, 0 wt% to 30 wt% manganese, and 0 wt% to 10 wt% lithium. The positive electrode active material may also contain aluminum in an amount of 0 wt% to 4 wt%. Preferably, the aluminum content is 1 wt% or less, and more preferably 0.1 wt% or less.
[0019] Next, examples and comparative examples of the present invention will be described. Note that the following examples are representative examples, and the present invention is not limited to these examples; it should be interpreted within the scope of the technical concept described in the specification.
[0020] (Example 1) A positive electrode material sample (20 cm x 20 cm) was irradiated with a laser at 2 kW for 40 seconds over a 20 cm square area. Then, the current collector and positive electrode active material were separated and sieved using a vibrating sieve with tapping balls. The content of each metal on and under the sieve is shown in Table 1. The recovery rate of the positive electrode active material was 88.5 wt%, which is a high recovery rate. The impurity (aluminum) content in the recovered positive electrode active material was 0.06 wt%.
[0021] (Comparative Example 1) Using the same positive electrode material sample as in Example 1, we attempted to separate and screen the current collector and positive electrode active material using a vibrating screen with tapping balls, without heating. As shown in Table 1, the vibrating screen alone was insufficient to separate the current collector and positive electrode active material.
[0022] (Comparative Example 2) Using the same positive electrode material sample as in Example 1, a laser was irradiated under the same conditions as in Example 1, and then the current collector and positive electrode active material were sieved using a sieve (mesh size: 1 mm). As shown in Table 1, only a very small amount of positive electrode active material, about 10 wt%, could be recovered.
[0023] (Comparative Example 3) Using the same positive electrode material sample as in Example 1, the sample was uniaxially crushed (crushing conditions: Horai cutter mill, screen diameter 9 mm), and then the current collector and positive electrode active material were separated and screened using a vibrating screen (screen size: 1 mm). As shown in Table 1, the recovery rate of the positive electrode active material was 76 wt%. The impurity (aluminum) content in the recovered positive electrode active material was 4.12 wt%.
[0024] (Comparative Example 4) A positive electrode material sample similar to that in Example 1 was heated in an electric furnace at 500°C for 2 hours, then uniaxially crushed (crushing conditions: Horai cutter mill, screen diameter 9 m), and the current collector and positive electrode active material were separated and screened using a vibrating screen (screen size: 1 mm). As shown in Table 1, the recovery rate of the positive electrode active material was 80 wt%. The impurity (aluminum) content in the recovered positive electrode active material was 1.6 wt%.
[0025]
[0026] According to this disclosure, the current collector and positive electrode active material contained in lithium-ion batteries can be effectively separated and recovered. This disclosure is useful for recycling used or unused lithium-ion batteries, as well as positive electrode scraps generated from the manufacturing process of lithium-ion batteries.
Claims
1. A method for recovering positive electrode active material and / or a current collector, characterized by comprising the steps of: irradiating a positive electrode material contained in a lithium-ion battery with a laser; separating the current collector and the positive electrode active material, or separating them during or after separation, recovering the current collector on the sieve, and recovering the positive electrode active material below the sieve.
2. The method for recovering a positive electrode active material and / or a current collector according to claim 1, characterized in that a laser is irradiated at an intensity such that the temperature of the positive electrode material is 300°C or higher and 660°C or lower.
3. A method for recovering positive electrode active material and / or current collector according to claim 2, characterized in that the laser irradiation time is greater than 0 seconds and 200 seconds or less.
4. The average power density of the laser should be 2 W / cm². ２ Above, 13W / cm ２ The method for recovering positive electrode active material and / or current collector according to claim 2, characterized in that it is as follows:
5. Set the integrated illuminance of the laser to 0 J / cm². ２ Super, 1000J / cm ２ The method for recovering positive electrode active material and / or current collector according to claim 4, characterized in that it is as follows:
6. The method for recovering positive electrode active material and / or current collector according to claim 1, characterized in that it includes a step of crushing the positive electrode material of the lithium-ion battery before the step of irradiating with the laser.
7. A positive electrode active material characterized by being recovered using the recovery method described in any one of claims 1 to 6.
8. The positive electrode active material material according to claim 7, characterized in that it contains one or more of nickel, cobalt, manganese, and lithium, with nickel in amounts of 0 wt% to 50 wt%, cobalt in amounts of 0 wt% to 50 wt%, manganese in amounts of 0 wt% to 30 wt%, and lithium in amounts of 0 wt% to 10 wt%.
9. The positive electrode active material material according to claim 8, characterized in that the aluminum content is 1 wt% or less.
10. A current collector material characterized by being recovered using the recovery method described in any one of claims 1 to 6.
11. The current collector material according to claim 10, characterized in that the aluminum content is 70 wt% or more.